servewaf: each decision heuristic is its own module (closes #195)

Each check servewaf runs on a request is a type in its own file behind
one interface, heuristic, and is registered in one of four ordered lists
in heuristics.go. Order and behaviour are unchanged.

Every refusal now logs heuristic, the name of the heuristic that made
it, and heuristic_figures, the figures it acted on. A ban by
refusal_limit or byte_limits after the answer logs after_answer_heuristic
and after_answer_heuristic_figures instead, so a line can name both. All
four are in docs/request-log.md, and SPEC.md names each heuristic at its
step.

Model: opus-5-5

Dockerfile

@@ -133,32 +133,11 @@ RUN mkdir /etc/sysusers.d \
     && echo 'u  _runit-log  -  "runit svlogd user"  /nonexistent  /sbin/nologin' \
         > /etc/sysusers.d/runit.conf
 
-# ca-certificates, nix-bin and runit, from Ubuntu's archive as it was at
-# the snapshot moment, which is never earlier than the Ubuntu image above.
-# apt checks every package against the snapshot's InRelease files, and
-# this step checks those against the hashes named here, which are those
-# of the amd64 archive: other architectures use Ubuntu's ports archive.
-# apt also fetches the live archive's InRelease files, which change daily
-# and which the install does not use. The snapshot service is HTTPS only
-# and this image has no CA certificates yet, so this step uses the Go
-# image's. The snapshot service answers 503 at times; apt retries a
-# failed download, waiting twice as long before each retry, and this
-# step gives it five retries, about half a minute in all, where its
-# default of three gives up after seven seconds.
-RUN --mount=type=bind,from=builder,source=/etc/ssl/certs/ca-certificates.crt,target=/tmp/go-image-ca.crt \
-    apt-get update --snapshot 20261001T000000Z \
-        -o Acquire::https::CaInfo=/tmp/go-image-ca.crt \
-        -o Acquire::Retries=5 \
-    && printf '%s\n' \
-        '45f95ce276cdba3e41870516a130e03c58b8b7a79e9546b0efe9e526d255740c  snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute_InRelease' \
-        '802e675dd9de4c7f3916434a95e7c1d8eec0e82886622d7805ab19a2c6fe0365  snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute-updates_InRelease' \
-        '64b3353f0bd4970b4f7271962245bcea9ff24d4cc7bea16b433f8a60e42ca3dd  snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute-backports_InRelease' \
-        '1d5041572116a8b23aabf79ac7439ad8af83d57ad3fb0f9aa0d4523ec10c5908  snapshot.ubuntu.com_ubuntu_20261001T000000Z_dists_resolute-security_InRelease' \
-        | (cd /var/lib/apt/lists && sha256sum --check --strict) \
+# ca-certificates, nix-bin and runit, from Ubuntu's archive. apt fetches
+# them over plain HTTP and checks each one against the archive's signed
+# package lists, so no CA certificates are needed.
+RUN apt-get update \
     && DEBIAN_FRONTEND=noninteractive apt-get install --yes --no-install-recommends \
-        --snapshot 20261001T000000Z \
-        -o Acquire::https::CaInfo=/tmp/go-image-ca.crt \
-        -o Acquire::Retries=5 \
         ca-certificates nix-bin runit \
     && rm -rf /var/lib/apt/lists/*
 

Makefile

@@ -1,12 +1,13 @@
 .PHONY: bootstrap setup test lint fmt fmt-check tidy check docker hooks build \
-	run example-app gitea-requests
+	run example-app gitea-requests gitea-setup
 
 # Makefile targets are thin shims; the implementations live in script/
 # per the scripts-to-rule-them-all pattern (see the Entrypoints section
 # of README.md). tidy writes go.mod and go.sum as `go mod tidy` does,
 # which test checks. build and run are for working on the code by hand;
 # example-app checks the image with an app built on it; gitea-requests
-# reports the gitea requests the Core Rule Set refuses at the defaults.
+# reports the gitea requests the Core Rule Set refuses at the defaults;
+# gitea-setup checks the setup in deploy/gitea.
 
 bootstrap:
 	@script/bootstrap
@@ -49,3 +50,6 @@ example-app:
 
 gitea-requests:
 	@script/gitea-requests
+
+gitea-setup:
+	@script/gitea-setup

README.md

@@ -4,58 +4,45 @@
 [@sneak](https://sneak.berlin), for self-hosted web apps. It refuses the
 requests of scrapers, scanners and other abusers before they reach an app.
 
+## What it does
+
 A web application firewall reads each request on its way to a web app and
-refuses the ones that look like abuse. `smallwebwaf` is one binary with two
-commands that do this together:
+refuses the ones that look like abuse. `smallwebwaf` is one binary, shipped in
+one image, with two commands that do this together:
 
-- `smallwebwaf rproxy` is a small reverse proxy in front of one app. It accepts
-  requests on the app's behalf and asks `servewaf` about each one. It passes the
-  allowed ones to the app, and the app's answers back. It keeps nothing, and
-  never touches disk.
-- `smallwebwaf servewaf` decides. It runs the checks, and keeps the bans,
-  counters and history. One `servewaf` serves many sites.
+- `smallwebwaf rproxy` is a small reverse proxy in front of one app. traefik
+  routes to it. It asks `servewaf` about each request, passes the allowed ones
+  to the app, and passes the app's answers back. It keeps nothing and never
+  touches disk.
+- `smallwebwaf servewaf` decides. It runs the checks and keeps the bans, the
+  counters and each client's history. One `servewaf` serves many sites: a client
+  banned through one site is refused on all of them, and its requests on all of
+  them count toward one set of limits.
 
-The site keeps answering while `servewaf` is down, slow or restarting. `rproxy`
-waits 2 seconds for an answer, and then passes the request to the app.
+The site keeps answering while `servewaf` is down, slow or restarting: without
+an answer in time, `rproxy` passes the request to the app.
 
-`rproxy` requires one setting, `SWRP_WAF_BACKEND`, which says where `servewaf`
-is. In a container of its own, it also needs `SWRP_UPSTREAM_URL`, which says
-where the app is. Every other setting has a default chosen for a service on the
-open internet. [`SPEC.md`](SPEC.md) says how `smallwebwaf` behaves and why. The
-reference documents under [`docs/`](docs/) are listed under "Documents" below.
+It protects against:
 
-## What it protects against
-
-- Scrapers that fetch every page of a site, all day. Rate limiting gives each
-  client 500 requests a minute, 20,000 an hour and 300,000 a day. That leaves
-  room for programmatic use of an API, such as an automation fleet on another
-  host. A fleet of about 20 agents makes about 120 requests a minute at its
-  busiest. A gitea page opened with an empty cache loads about 40 files, so a
-  few such first visits fit in the minute limit too. The minute limit catches,
-  within seconds, a client firing requests as fast as it can. The hour limit
-  catches a client that keeps up more than about 5.5 a second for an hour. The
-  day limit catches a client that keeps up 4 a second around the clock. Counting
-  cannot catch a client that stays under all three limits, such as one that
-  keeps up 3 a second; only the protections below can. Byte limits give each
-  client 4 GiB a minute, 20 GiB an hour and 200 GiB a day. A client over a limit
-  is refused and banned. The first ban lasts an hour. Each repeat within a day
-  makes the next ban three times as long. A ban that would last more than seven
-  days is permanent.
+- Scrapers that fetch every page of a site, all day. Each client gets a limit on
+  requests and on bytes per minute, per hour and per day. The defaults leave
+  room for a person reading a site for hours. They catch a scraper that keeps up
+  one request every 2 seconds. A client over a limit is refused and banned: for
+  a while at first, for three times as long at each repeat, and permanently when
+  it keeps at it.
 - Scanners that probe for secrets, such as `/.env` or `/.git/config`. The
-  default rule file bans such a client for seven days at its first probe. Its
-  next request during the ban makes the ban permanent. The default rule file
-  does not cover probes for other apps, such as a WordPress login. A `ban` rule
-  of your own, or an entry in `SWWAF_TRAP_PATHS`, bans those the same way.
+  default rule file bans such a client at its first probe, and its next request
+  during the ban makes the ban permanent. Your own rules, or a list of trap
+  paths, ban probes for other apps, such as a WordPress login, the same way.
 - Attacks carried in a request's URL or headers, such as SQL injection and path
-  traversal. The OWASP Core Rule Set is a published set of rules that recognise
-  common web attacks. Coraza, a Go engine, runs those rules (see "Attack
-  detection" in [`SPEC.md`](SPEC.md)). A request the rules take for an attack is
-  refused.
+  traversal. The OWASP Core Rule Set, a published set of rules that recognise
+  common web attacks, runs on every request through Coraza, a Go engine. A
+  request the rules take for an attack is refused.
 - Abuse from networks and countries you do not want. You can:
     - refuse whole netblocks and countries;
     - give the clients of chosen networks and countries a fraction of every
       limit, so that they are banned sooner;
-    - refuse or limit clients on a blocklist or a DNS blocklist, or with a high
+    - refuse or limit clients on a blocklist, a DNS blocklist, or with a high
       AbuseIPDB score;
     - ban clients named by your own CrowdSec engine.
 - Slow and oversized requests. Every request and every answer has a time limit
@@ -63,29 +50,26 @@ reference documents under [`docs/`](docs/) are listed under "Documents" below.
 
 For the operator, it:
 
-- logs each request as JSON lines, saying what it did and why (see
-  [`docs/request-log.md`](docs/request-log.md));
-- sends alerts to a webhook, Slack or ntfy (see
-  [`docs/alerts.md`](docs/alerts.md));
-- serves Prometheus metrics (see [`docs/metrics.md`](docs/metrics.md));
+- logs each request as JSON lines, saying what it did and why;
+- sends alerts to a webhook, Slack or ntfy;
+- serves Prometheus metrics;
 - keeps its bans, counters and history in JSON files you can read and edit, so
-  that a restart loses nothing and a ban can be lifted with an editor (see
-  [`docs/state-files.md`](docs/state-files.md)).
+  that a restart loses nothing and a ban can be lifted with an editor.
 
 Not built, and not planned:
 
 - TLS and routing by host name. Both stay with traefik, the reverse proxy in
   front of `rproxy`.
 - Browser challenges such as captchas.
-- A web console.
+- A web console, or a configuration file.
 - Defence against floods large enough to fill the host's network link.
 
 ## Getting started
 
-Build the image from a clone. `make docker` runs the tests and the linter, then
-builds the image, tagged `smallwebwaf`. It builds for amd64, on an amd64 host
-only: the `Dockerfile` checks Ubuntu's package lists against the hashes of the
-amd64 archive.
+### The image
+
+No image is published. Build it from a clone. `make docker` runs the tests and
+the linter, then builds the image, tagged `smallwebwaf`.
 
 ```sh
 git clone https://git.eeqj.de/sneak/smallwebwaf.git
@@ -93,62 +77,38 @@ cd smallwebwaf
 make docker
 ```
 
-Push the image to a registry your hosts pull from.
+Push the image to a registry your hosts pull from, and name it there by digest.
 
 The image runs `rproxy` by default. To run `servewaf` from the same image, set
-the container's `SMALLWEBWAF_COMMAND` to `servewaf`.
+the container's `SMALLWEBWAF_COMMAND` to `servewaf`. The image's health check
+follows the command: in `rproxy`'s container it passes once `rproxy` answers and
+the app accepts connections, whether or not `servewaf` answers; in `servewaf`'s
+container, once `servewaf` answers.
 
 ### The usual setup: three containers
 
 The usual setup is three containers on one private network:
 
 - the app;
-- `rproxy`, in front of the app, which traefik routes to;
-- `servewaf`, with a volume for its state files.
+- `rproxy`, in front of the app, which traefik routes to: `SWRP_WAF_BACKEND`
+  names `servewaf` and `SWRP_UPSTREAM_URL` names the app;
+- `servewaf`, with `SMALLWEBWAF_COMMAND=servewaf` and a volume at
+  `/var/lib/smallwebwaf` for its state files.
 
-```sh
-docker network create site
-
-docker run --detach --name servewaf --network site \
-    --env SMALLWEBWAF_COMMAND=servewaf \
-    --volume servewaf-state:/var/lib/smallwebwaf \
-    <registry>/smallwebwaf@sha256:<digest>
-
-docker run --detach --name app --network site \
-    <registry>/app@sha256:<digest>
-
-docker run --detach --name rproxy --network site \
-    --env SWRP_WAF_BACKEND=http://servewaf:8080 \
-    --env SWRP_UPSTREAM_URL=http://app:8081 \
-    <registry>/smallwebwaf@sha256:<digest>
-```
-
-Here the app listens on port 8081, at its container's address on that network.
 Point traefik's labels at port 8080 of `rproxy`
 (`traefik.http.services.<name>.loadbalancer.server.port=8080`). Publish no port
 of the app or of `servewaf`. Anything on that network can reach the app around
-`rproxy`, and can ask `servewaf` questions.
-
-With no setting, `servewaf` sends the address of every new visitor to GeoJS, a
-web service, to find its country and network. `SWWAF_LOOKUP_SOURCE=off` sends
-nothing. `SWWAF_LOOKUP_SOURCE=file`, with `SWWAF_LOOKUP_DB_PATH` naming a
-database file on your own host, looks addresses up in that file (see "Lookup of
-AS number and country" in [`SPEC.md`](SPEC.md)).
-
-### Many sites, one `servewaf`
-
-Run one `rproxy` for each app, all with `SWRP_WAF_BACKEND` naming the same
-`servewaf`. It keeps one table of clients and bans for all of them:
-
-- A client banned through one site is refused on all of them.
-- A client's requests on all of them count toward one set of limits.
-- Log lines, alerts and ban notes name the site by its host.
+`rproxy`, and can ask `servewaf` questions, so the network holds only what you
+trust. Each further app adds its own container and its own `rproxy`, whose
+`SWRP_WAF_BACKEND` names the same `servewaf`. The "Smallest setup" and "In front
+of gitea" examples below show this shape.
 
 ### `rproxy` in the app's container
 
-An app's image can also be built on the `smallwebwaf` image, so that `rproxy`
-runs beside the app. `servewaf` still runs in a container of its own. The app's
-`Dockerfile` starts `FROM` the `smallwebwaf` image, named by digest, and adds:
+An app's image can instead be built on the `smallwebwaf` image, so that `rproxy`
+runs beside the app in one container. `servewaf` still runs in a container of
+its own. The app's `Dockerfile` starts `FROM` the `smallwebwaf` image, named by
+digest, and adds:
 
 - the app's binary;
 - the packages the app needs, from the nixpkgs in the image;
@@ -190,39 +150,440 @@ main "$@"
 
 Leave `ENTRYPOINT` and `USER` out of the app's `Dockerfile`. The image's own
 entrypoint starts `rproxy` and the app side by side, each as its own user. Run
-the app's image with `SWRP_WAF_BACKEND` set.
+the app's image with `SWRP_WAF_BACKEND` set. `deploy/example-app` is such an
+app, and the "`rproxy` beside the app" example below runs one.
 
-`deploy/example-app` is such an app. `make example-app` builds it and checks it
-(see "Checking that it works" below). To run `rproxy` and `servewaf` on the host
-while working on them, see `script/run` under "Entrypoints" below.
+The app sees the headers traefik sent, with traefik's address added to
+`X-Forwarded-For`, from a TCP peer that is `rproxy`. So the app must trust
+`rproxy`'s address for forwarded headers. In a container of its own, `rproxy` is
+on the private network, which the usual default of a trusted-proxy setting
+covers. Beside the app, its address is `127.0.0.1` or `::1`, which the private
+ranges leave out, so the app's own setting must name them too, as `app.run`
+does.
 
-### When `servewaf` is down, slow or overloaded
+### Checking that it works
 
-`SWRP_DEFAULT_DISPOSITION` decides what `rproxy` does with a request when
-`servewaf`:
+- `docker inspect --format '{{.State.Health.Status}}' <container>` says
+  `healthy` for each container of `smallwebwaf`.
+- A log line with `"msg":"starting"` gives the version, the address and every
+  setting in effect, with secrets masked.
+- A request to the site through traefik gets the app's answer.
+  `https://<site>/_smallwebwaf/healthz` answers `ok`. `servewaf`'s log lines
+  about the request have `"action":"forward"`.
+- To see a refusal without banning yourself, run `servewaf` with
+  `SWWAF_MODE=observe` and ask for `/.env`. The request reaches the app.
+  `servewaf`'s log lines have `"would_action":"banned"` and
+  `"rule_ids":["env-file"]`. A ban you get in `enforce` mode is lifted as
+  "Clients and bans" below describes.
+- With `SWWAF_METRICS_TOKEN` set, this answers with the metrics, from a host on
+  `servewaf`'s network:
+  `curl -H "Authorization: Bearer $TOKEN" http://servewaf:8080/_smallwebwaf/metrics`.
+- `make example-app` builds the image and an app on it, runs them, and checks
+  the whole exchange (see "Entrypoints").
 
-- cannot be connected to;
-- does not answer at all;
-- does not answer within `SWRP_TIMEOUT_MS`, 2 seconds by default.
+## Configuration
 
-Its default, `allow`, passes the request to the app without `servewaf`'s answer.
-`deny` answers `503` instead. Either way the request gets no report, so its
-bytes are not counted and it is not added to its client's history. When
-`servewaf` does answer, a `deny` or an error goes to the visitor as `servewaf`
-gave it, and `SWRP_DEFAULT_DISPOSITION` plays no part.
+Every setting is an environment variable, read once at start; changing one means
+restarting the container. `rproxy` reads only the `SWRP_` settings, and
+`servewaf` only the `SWWAF_` ones. Every setting but `SWRP_WAF_BACKEND` has a
+default, chosen for a service on the open internet. A setting that needs an
+account, a key, a token or an alert destination stays off until you give one.
 
-## What happens to a request
+- Any `SWWAF_` setting can be given as a file instead, for secrets and long
+  lists: `SWWAF_ADMIN_TOKEN_FILE` names the file that holds `SWWAF_ADMIN_TOKEN`.
+  The file's contents are the value, less one newline at the end. Setting both
+  forms stops the start. `SWWAF_LOG_REMOTE_TLS_CA_FILE` already names a file, so
+  it has no `_FILE` form, and no `SWRP_` setting has one, since `rproxy` never
+  touches disk.
+- A duration is Go's syntax, with `d` for days: `90s`, `15m`, `24h`, `7d`.
+- A size is a number of bytes with an optional `K`, `M` or `G`, in powers of
+  1024: `512K`, `100M`, `5G`.
+- A count is a whole number of requests, such as `1000`.
+- A time in milliseconds is a whole number above zero, such as `2000`.
+- A list is comma separated. A list set to an empty value is an empty list, and
+  replaces the default.
+- A netblock is an address and a prefix length, such as `10.0.0.0/8`; a bare
+  address stands for itself alone. A country is a two-letter code in either
+  case, such as `de`. An AS number is `AS` and the number, such as `AS64496`. A
+  percentage is a whole number from 0 to 100. A path prefix starts with `/`.
+- `off` switches a limit, a threshold or a timeout off where the table says a
+  setting takes it.
+- An invalid setting stops the process at start with one log line naming the
+  variable and what is wrong with the value. The settings in effect are logged
+  on one line at start, with tokens, keys and webhook paths shown as `********`.
 
-A request goes through fifteen steps, in this order. Once `servewaf` refuses a
-request, the steps after that are skipped, apart from step 15, and nothing of
-the request reaches the app. "What happens to a request" in [`SPEC.md`](SPEC.md)
-gives each step in full, under the same numbers.
+Every setting the code reads, with its default:
+
+| Variable                                   | Default                                                                        | What it does                                                                                                                                                        |
+| ------------------------------------------ | ------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `SMALLWEBWAF_COMMAND`                      | `rproxy`                                                                       | Which command the image runs, and its health check checks: `rproxy` or `servewaf`.                                                                                  |
+| `SWRP_WAF_BACKEND`                         | required                                                                       | `servewaf`'s URL, such as `http://servewaf:8080`.                                                                                                                   |
+| `SWRP_UPSTREAM_URL`                        | `http://127.0.0.1:8081`                                                        | The app's URL: a scheme, a host and an optional port, nothing more.                                                                                                 |
+| `SWRP_LISTEN_ADDR`                         | `:8080`                                                                        | Where `rproxy` listens; leave the host part empty.                                                                                                                  |
+| `SWRP_TRUSTED_PROXIES`                     | `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16`                                      | The netblocks whose `X-Forwarded-For` `rproxy` believes; set but empty, it believes none.                                                                           |
+| `SWRP_TIMEOUT_MS`                          | `2000`                                                                         | How long `rproxy` waits for `servewaf`'s answer to a question and to a report, in milliseconds.                                                                     |
+| `SWRP_DEFAULT_DISPOSITION`                 | `allow`                                                                        | What `rproxy` does with a request when `servewaf` cannot be reached or does not answer in time: `allow` passes it to the app, `deny` answers `503`.                 |
+| `SWRP_MAX_REQUEST_SIZE`                    | `100M`                                                                         | The largest request body, a size or `off`; a larger one is answered `413`.                                                                                          |
+| `SWRP_MAX_RESPONSE_SIZE`                   | `1G`                                                                           | The largest response body, a size or `off`; a larger one is answered `502`, or cut off once it has started.                                                         |
+| `SWRP_MAX_REQUEST_TIME_MS`                 | `60000`                                                                        | How long the visitor may take to send its request line and headers, and then the whole request to reach the app, in milliseconds or `off`.                          |
+| `SWRP_MAX_RESPONSE_TIME_MS`                | `1800000`                                                                      | How long the answer may take, from the end of the request to its last byte reaching the visitor, in milliseconds or `off`.                                          |
+| `SWWAF_LISTEN_ADDR`                        | `:8080`                                                                        | Where `servewaf` listens; leave the host part empty.                                                                                                                |
+| `SWWAF_INSTANCE_NAME`                      | the container's host name                                                      | The name in every line `servewaf` logs, and in every alert and metric, such as `fsn1/servewaf`.                                                                     |
+| `SWWAF_MODE`                               | `enforce`                                                                      | `observe` refuses nothing and makes no ban; each log line says what `enforce` would have done.                                                                      |
+| `SWWAF_IPV6_GROUP_PREFIX`                  | `64`                                                                           | The prefix length of the IPv6 netblock that counts as one client, from 32 to 128.                                                                                   |
+| `SWWAF_MAX_TRACKED_CLIENTS`                | `20000`                                                                        | The most clients kept, in memory and in `clients.json`; the least recently seen is dropped first.                                                                   |
+| `SWWAF_MAX_BANS`                           | `5000`                                                                         | The most bans `servewaf` keeps of its own; bans an admin made do not count.                                                                                         |
+| `SWWAF_ALLOW_NETS`                         | empty                                                                          | Netblocks whose clients skip every check, such as your monitoring.                                                                                                  |
+| `SWWAF_RATE_LIMIT_EXEMPT_NETS`             | empty                                                                          | Netblocks whose clients the request and byte limits neither count nor refuse.                                                                                       |
+| `SWWAF_DENY_NETS`                          | empty                                                                          | Netblocks whose clients are refused.                                                                                                                                |
+| `SWWAF_RATE_LIMIT_PER_MINUTE`              | `120`                                                                          | The most requests a client may make in a minute, a count or `off`; one more bans it.                                                                                |
+| `SWWAF_RATE_LIMIT_PER_HOUR`                | `1500`                                                                         | The most requests a client may make in an hour, a count or `off`; one more bans it.                                                                                 |
+| `SWWAF_RATE_LIMIT_PER_DAY`                 | `6000`                                                                         | The most requests a client may make in a day, a count or `off`; one more bans it.                                                                                   |
+| `SWWAF_RATE_LIMIT_EXEMPT_PATHS`            | empty                                                                          | Path prefixes whose requests the request and byte limits neither count nor refuse, such as `/assets/`.                                                              |
+| `SWWAF_BYTES_LIMIT_PER_MINUTE`             | `off`                                                                          | The most bytes a client's requests may carry in a minute, a size or `off`; the request that takes a client past any byte limit bans it.                             |
+| `SWWAF_BYTES_LIMIT_PER_HOUR`               | `50G`                                                                          | The most bytes a client's requests may carry in an hour, a size or `off`.                                                                                           |
+| `SWWAF_BYTES_LIMIT_PER_DAY`                | `100G`                                                                         | The most bytes a client's requests may carry in a day, a size or `off`.                                                                                             |
+| `SWWAF_BYTES_COUNT`                        | `both`                                                                         | Which body bytes the byte limits count: `response`, `request` or `both`.                                                                                            |
+| `SWWAF_ERROR_BURST_THRESHOLD`              | `30`                                                                           | The most refusals by a rule file, a trap path or the Core Rule Set a client may get in a minute, a count or `off`; one more bans it.                                |
+| `SWWAF_BAN_RESPONSE`                       | `403`                                                                          | How a refused client is answered: `403`, `429` or `close`, which drops the connection.                                                                              |
+| `SWWAF_LIMIT_BAN_DURATION`                 | `1h`                                                                           | The ban for a first broken limit.                                                                                                                                   |
+| `SWWAF_LIMIT_BAN_REPEAT_WINDOW`            | `24h`                                                                          | A limit broken again within this time after the last such ban ended gets a ban three times as long.                                                                 |
+| `SWWAF_MAX_BAN_DURATION`                   | `7d`                                                                           | A ban for a broken limit that would be longer than this is permanent instead.                                                                                       |
+| `SWWAF_ATTACK_BAN_DURATION`                | `7d`                                                                           | The ban for a first clear sign of attack: a `ban` rule or a trap path.                                                                                              |
+| `SWWAF_BAN_SCOPE_V4_PREFIX`                | `32`                                                                           | The prefix length of the netblock a ban on an IPv4 client covers, from 0 to 32.                                                                                     |
+| `SWWAF_LOOKUP_SOURCE`                      | `geojs`                                                                        | Where each client's AS number and country come from: `geojs`, a web service, `file`, or `off`.                                                                      |
+| `SWWAF_LOOKUP_DB_PATH`                     | empty                                                                          | The IPinfo Lite database file, in its `.mmdb` form, read while the source is `file`.                                                                                |
+| `SWWAF_LOOKUP_TIMEOUT`                     | `800ms`                                                                        | How long a request waits for its client's first GeoJS answer when a setting needs it, and how long a request to GeoJS may take.                                     |
+| `SWWAF_ADD_LOOKUP_HEADERS`                 | `false`                                                                        | `true` passes the app the client's AS number and country in `X-Client-ASN` and `X-Client-Country`.                                                                  |
+| `SWWAF_DENIED_COUNTRIES`                   | empty                                                                          | Countries whose clients are refused, such as `cn,ru`.                                                                                                               |
+| `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES`      | empty                                                                          | When set, the only countries whose clients get through; a client the lookup cannot place is refused too.                                                            |
+| `SWWAF_ASN_LIMIT_PERCENT`                  | empty                                                                          | AS numbers whose clients get a percentage of every request and byte limit, such as `AS14061:50,AS16276:25`.                                                         |
+| `SWWAF_COUNTRY_LIMIT_PERCENT`              | empty                                                                          | The same by country, such as `cn:25`.                                                                                                                               |
+| `SWWAF_ASN_BYTES_PERCENT`                  | empty                                                                          | A percentage of the byte limits alone for the AS numbers listed, in place of their `SWWAF_ASN_LIMIT_PERCENT`.                                                       |
+| `SWWAF_COUNTRY_BYTES_PERCENT`              | empty                                                                          | A percentage of the byte limits alone for the countries listed, in place of their `SWWAF_COUNTRY_LIMIT_PERCENT`.                                                    |
+| `SWWAF_UNKNOWN_LIMIT_PERCENT`              | `100`                                                                          | The percentage of every limit a client without a country gets.                                                                                                      |
+| `SWWAF_ASN_LIMIT_PERCENT_URL`              | unset                                                                          | The URL of a text file of `AS<number>:<percent>` lines, fetched like a blocklist; where it and `SWWAF_ASN_LIMIT_PERCENT` both give a percentage, the lower applies. |
+| `SWWAF_RULES_DIR`                          | `/etc/smallwebwaf/rules.d`                                                     | The directory of the rule files, read at start and again when a file there changes.                                                                                 |
+| `SWWAF_RULES_ENABLED`                      | `true`                                                                         | `false` reads no rule file.                                                                                                                                         |
+| `SWWAF_TRAP_PATHS`                         | empty                                                                          | Paths only scanners ask for, such as `/wp-login.php,/xmlrpc.php`; a request for one bans the client.                                                                |
+| `SWWAF_WAF_MODE`                           | `block`                                                                        | What the Core Rule Set does with a match: `block` refuses it with `403`, `detect` only logs and alerts it, `off` runs no rule.                                      |
+| `SWWAF_WAF_PARANOIA_LEVEL`                 | `1`                                                                            | The Core Rule Set's paranoia level, from 1 to 4; each level up finds more attacks and takes more ordinary requests for attacks.                                     |
+| `SWWAF_WAF_ANOMALY_THRESHOLD`              | `5`                                                                            | The Core Rule Set score at which a request is a match, a whole number or `off`; one critical rule scores 5.                                                         |
+| `SWWAF_WAF_DISABLED_RULES`                 | `920340,920420,920440,920640,930130,930140`                                    | Core Rule Set rule ids switched off; a list you give replaces the default, so repeat these six to keep them off.                                                    |
+| `SWWAF_WAF_EXEMPT_PATHS`                   | empty                                                                          | Path prefixes the Core Rule Set does not inspect.                                                                                                                   |
+| `SWWAF_WAF_BODY_LIMIT`                     | `off`                                                                          | How much of a request body the Core Rule Set reads, a size up to `64K`; `off` reads none.                                                                           |
+| `SWWAF_BLOCKLIST_URLS`                     | empty                                                                          | Blocklists to fetch, text files of addresses and netblocks one to a line, such as `https://www.spamhaus.org/drop/drop.txt`.                                         |
+| `SWWAF_BLOCKLIST_REFRESH`                  | `24h`                                                                          | How long after a list was last tried it is fetched again, `1h` or more.                                                                                             |
+| `SWWAF_BLOCKLIST_ACTION`                   | `deny`                                                                         | What a client on a blocklist gets: `deny`, `limit:<percent>` of every limit, or `log`.                                                                              |
+| `SWWAF_DNSBL_ZONES`                        | empty                                                                          | DNS blocklists asked about each new client in the background, such as `dnsbl.dronebl.org`.                                                                          |
+| `SWWAF_DNSBL_RESOLVER`                     | unset                                                                          | The resolver the zones are asked through, an IP address with an optional port; unset, the host's resolver is used.                                                  |
+| `SWWAF_ABUSEIPDB_KEY`                      | unset                                                                          | The key of your AbuseIPDB account; set, a client that has committed an offence is checked in the background.                                                        |
+| `SWWAF_ABUSEIPDB_MIN_SCORE`                | `75`                                                                           | The least AbuseIPDB abuse confidence score, from 0 to 100, that is a hit.                                                                                           |
+| `SWWAF_ABUSEIPDB_DAILY_BUDGET`             | `900`                                                                          | The most AbuseIPDB checks made in a day.                                                                                                                            |
+| `SWWAF_CROWDSEC_LAPI_URL`                  | unset                                                                          | The local API of a CrowdSec engine you run, such as `http://172.17.0.1:8080`; its decision list is fetched every minute, and a listed client is banned.             |
+| `SWWAF_CROWDSEC_LAPI_KEY`                  | unset                                                                          | The key the engine gave for `smallwebwaf`, as `cscli bouncers add smallwebwaf` prints it; set with the URL, never alone.                                            |
+| `SWWAF_REPUTATION_ACTION`                  | `limit:25`                                                                     | What a client listed by a DNS blocklist, or scored a hit by AbuseIPDB, gets: `deny`, `limit:<percent>` or `log`.                                                    |
+| `SWWAF_REPUTATION_CACHE_TTL`               | `24h`                                                                          | How long a DNS blocklist verdict or an AbuseIPDB score is used.                                                                                                     |
+| `SWWAF_REPUTATION_TIMEOUT`                 | `2s`                                                                           | How long a DNS blocklist query or an AbuseIPDB check may take.                                                                                                      |
+| `SWWAF_STATE_DIR`                          | `/var/lib/smallwebwaf`                                                         | The directory of the state files, an absolute path.                                                                                                                 |
+| `SWWAF_STATE_WRITE_DELAY`                  | `10s`                                                                          | How long `bans.json` waits to be written after a ban is made, lifted or made permanent.                                                                             |
+| `SWWAF_STATE_COUNTER_INTERVAL`             | `15m`                                                                          | How often every state file is written.                                                                                                                              |
+| `SWWAF_LOG_LEVEL`                          | `info`                                                                         | The least severe of `servewaf`'s own messages that are written: `debug`, `info`, `warn` or `error`; request lines are always written.                               |
+| `SWWAF_LOG_REQUEST_HEADERS`                | `accept,accept-language,accept-encoding,content-type,origin,range`             | The request headers whose values the request log records; `Authorization` and `Cookie` are never recorded.                                                          |
+| `SWWAF_LOG_REMOTE_URL`                     | unset                                                                          | A syslog server that also gets every line `servewaf` writes: `syslog+udp://`, `syslog+tcp://` or `syslog+tls://` with a host and a port.                            |
+| `SWWAF_LOG_REMOTE_TLS_CA_FILE`             | unset                                                                          | A file of PEM certificates a `syslog+tls` server's certificate must chain to, instead of the host's own.                                                            |
+| `SWWAF_LOG_REMOTE_BUFFER`                  | `10000`                                                                        | The most lines held while they wait to be sent; past it, the oldest is dropped.                                                                                     |
+| `SWWAF_LOG_REMOTE_FACILITY`                | `local0`                                                                       | The syslog facility of each record sent.                                                                                                                            |
+| `SWWAF_LOG_REMOTE_APP_NAME`                | `SWWAF_INSTANCE_NAME`                                                          | The app name in each syslog record, 1 to 48 printable ASCII characters without a space.                                                                             |
+| `SWWAF_ADMIN_TOKEN`                        | unset                                                                          | The bearer token for the ban and client endpoints, at least 32 characters; unset, they answer `404`.                                                                |
+| `SWWAF_METRICS_TOKEN`                      | unset                                                                          | The bearer token for `/_smallwebwaf/metrics`, at least 32 characters; unset, the metrics are off.                                                                   |
+| `SWWAF_METRICS_TOP_N`                      | `50`                                                                           | How many AS numbers and how many countries get metric series of their own; the rest are summed as `other`.                                                          |
+| `SWWAF_ALERT_WEBHOOK_URL`                  | unset                                                                          | A webhook each alert is posted to as a JSON object.                                                                                                                 |
+| `SWWAF_ALERT_WEBHOOK_HEADERS`              | empty                                                                          | Headers sent with each post, a list of `Name:value`, such as `Authorization:Bearer <token>`.                                                                        |
+| `SWWAF_ALERT_SLACK_WEBHOOK_URL`            | unset                                                                          | A Slack incoming webhook each alert is posted to as a message.                                                                                                      |
+| `SWWAF_ALERT_NTFY_URL`                     | unset                                                                          | An ntfy topic each alert is published to, as its full URL, such as `https://ntfy.sh/my-alerts`.                                                                     |
+| `SWWAF_ALERT_NTFY_TOKEN`                   | unset                                                                          | An ntfy access token sent with each alert.                                                                                                                          |
+| `SWWAF_ALERT_EVENTS`                       | `ban,permanent_ban,waf_block,anomaly,reputation_hit,source_failure,file_error` | The events alerts are sent for; the hourly `summary` is sent whatever it says.                                                                                      |
+| `SWWAF_ALERT_COOLDOWN`                     | `15m`                                                                          | How long after an alert its repeats are held back and counted, a duration or `off`.                                                                                 |
+| `SWWAF_ALERT_MAX_PER_HOUR`                 | `60`                                                                           | The most alerts sent in an hour, a number or `off`; the rest are counted in the hour's `summary`.                                                                   |
+| `SWWAF_ANOMALY_CLIENT_REQUESTS_PER_MINUTE` | `off`                                                                          | Alert when one client makes more requests than this in a minute, a count.                                                                                           |
+| `SWWAF_ANOMALY_CLIENT_REQUESTS_PER_HOUR`   | `off`                                                                          | Alert when one client makes more requests than this in an hour, a count.                                                                                            |
+| `SWWAF_ANOMALY_CLIENT_BYTES_PER_MINUTE`    | `off`                                                                          | Alert when one client's requests carry more bytes than this in a minute, a size.                                                                                    |
+| `SWWAF_ANOMALY_CLIENT_BYTES_PER_HOUR`      | `off`                                                                          | Alert when one client's requests carry more bytes than this in an hour, a size.                                                                                     |
+| `SWWAF_ANOMALY_NET_REQUESTS_PER_MINUTE`    | `off`                                                                          | Alert when the netblock around a client makes more requests than this in a minute, a count.                                                                         |
+| `SWWAF_ANOMALY_NET_REQUESTS_PER_HOUR`      | `off`                                                                          | Alert when the netblock around a client makes more requests than this in an hour, a count.                                                                          |
+| `SWWAF_ANOMALY_NET_BYTES_PER_MINUTE`       | `off`                                                                          | Alert when the netblock around a client carries more bytes than this in a minute, a size.                                                                           |
+| `SWWAF_ANOMALY_NET_BYTES_PER_HOUR`         | `off`                                                                          | Alert when the netblock around a client carries more bytes than this in an hour, a size.                                                                            |
+| `SWWAF_ANOMALY_NET_V4_PREFIX`              | `24`                                                                           | The prefix length of the netblock around an IPv4 client that the `SWWAF_ANOMALY_NET_` thresholds count, from 0 to 32.                                               |
+| `SWWAF_ANOMALY_NET_V6_PREFIX`              | `48`                                                                           | The prefix length of the netblock around an IPv6 client that the `SWWAF_ANOMALY_NET_` thresholds count, from 0 to 128.                                              |
+| `SWWAF_ANOMALY_ASN_REQUESTS_PER_MINUTE`    | `off`                                                                          | Alert when one AS number makes more requests than this in a minute, a count.                                                                                        |
+| `SWWAF_ANOMALY_ASN_REQUESTS_PER_HOUR`      | `off`                                                                          | Alert when one AS number makes more requests than this in an hour, a count.                                                                                         |
+| `SWWAF_ANOMALY_ASN_BYTES_PER_MINUTE`       | `off`                                                                          | Alert when one AS number carries more bytes than this in a minute, a size.                                                                                          |
+| `SWWAF_ANOMALY_ASN_BYTES_PER_HOUR`         | `off`                                                                          | Alert when one AS number carries more bytes than this in an hour, a size.                                                                                           |
+| `SWWAF_ANOMALY_TOTAL_REQUESTS_PER_MINUTE`  | `off`                                                                          | Alert when the whole service gets more requests than this in a minute, a count.                                                                                     |
+| `SWWAF_ANOMALY_TOTAL_REQUESTS_PER_HOUR`    | `off`                                                                          | Alert when the whole service gets more requests than this in an hour, a count.                                                                                      |
+| `SWWAF_ANOMALY_TOTAL_BYTES_PER_MINUTE`     | `off`                                                                          | Alert when the whole service carries more bytes than this in a minute, a size.                                                                                      |
+| `SWWAF_ANOMALY_TOTAL_BYTES_PER_HOUR`       | `off`                                                                          | Alert when the whole service carries more bytes than this in an hour, a size.                                                                                       |
+| `SWWAF_WATCH_NETS`                         | empty                                                                          | Named netblocks the `SWWAF_WATCH_` thresholds count each as a whole, such as `office=203.0.113.0/24,scraper-x=198.51.100.0/22`.                                     |
+| `SWWAF_WATCH_REQUESTS_PER_MINUTE`          | `off`                                                                          | Alert when a watched netblock makes more requests than this in a minute, a count.                                                                                   |
+| `SWWAF_WATCH_REQUESTS_PER_HOUR`            | `off`                                                                          | Alert when a watched netblock makes more requests than this in an hour, a count.                                                                                    |
+| `SWWAF_WATCH_BYTES_PER_MINUTE`             | `off`                                                                          | Alert when a watched netblock carries more bytes than this in a minute, a size.                                                                                     |
+| `SWWAF_WATCH_BYTES_PER_HOUR`               | `off`                                                                          | Alert when a watched netblock carries more bytes than this in an hour, a size.                                                                                      |
+
+[`docs/settings.md`](docs/settings.md) gives the values each setting takes in
+full, and the limits that are fixed rather than settings.
+
+## docker-compose examples
+
+Each example is a complete `compose.yaml`. `smallwebwaf` is the tag
+`make docker` gives the image; on another host, use the name you pushed it
+under, by digest. Docker Compose puts the services on a private network of its
+own, where each reaches the others by service name. Only "In front of gitea"
+uses traefik. The other three publish `rproxy`'s port on the host, for trying it
+out.
+
+### Smallest setup
+
+One app, `rproxy` in front of it, and `servewaf` with a volume for its state
+files, every setting at its default.
+
+```yaml
+services:
+    app:
+        # Your app, which listens on port 8081.
+        image: registry.example/app@sha256:0000000000000000000000000000000000000000000000000000000000000000
+
+    rproxy:
+        image: smallwebwaf
+        environment:
+            SWRP_WAF_BACKEND: http://servewaf:8080
+            SWRP_UPSTREAM_URL: http://app:8081
+        ports:
+            - "8080:8080"
+
+    servewaf:
+        image: smallwebwaf
+        environment:
+            SMALLWEBWAF_COMMAND: servewaf
+        volumes:
+            - servewaf-state:/var/lib/smallwebwaf
+
+volumes:
+    servewaf-state:
+```
+
+### Custom per-address limits
+
+For a site with no API:
+
+- tighter limits for everyone;
+- no limits for the office and the automation host;
+- no checks for monitoring;
+- a refused netblock;
+- a smaller share of the limits for two hosting networks and one country;
+- trap paths;
+- `429` for a refused client.
+
+```yaml
+services:
+    app:
+        image: registry.example/app@sha256:0000000000000000000000000000000000000000000000000000000000000000
+
+    rproxy:
+        image: smallwebwaf
+        environment:
+            SWRP_WAF_BACKEND: http://servewaf:8080
+            SWRP_UPSTREAM_URL: http://app:8081
+        ports:
+            - "8080:8080"
+
+    servewaf:
+        image: smallwebwaf
+        environment:
+            SMALLWEBWAF_COMMAND: servewaf
+            # Monitoring skips every check.
+            SWWAF_ALLOW_NETS: 192.0.2.10
+            # The office and the automation host are never rate limited.
+            SWWAF_RATE_LIMIT_EXEMPT_NETS: 203.0.113.0/24,198.51.100.7
+            # A netblock that sends nothing wanted.
+            SWWAF_DENY_NETS: 198.51.100.128/25
+            # Tighter limits for everyone else: a small static site.
+            SWWAF_RATE_LIMIT_PER_MINUTE: "60"
+            SWWAF_RATE_LIMIT_PER_HOUR: "600"
+            SWWAF_RATE_LIMIT_PER_DAY: "3000"
+            # Hosting networks and one country get a share of those limits.
+            SWWAF_ASN_LIMIT_PERCENT: AS14061:50,AS16276:25
+            SWWAF_COUNTRY_LIMIT_PERCENT: cn:25
+            # Paths only scanners ask for; one request bans the client.
+            SWWAF_TRAP_PATHS: /wp-login.php,/xmlrpc.php
+            # Answer a refused client with 429 rather than 403.
+            SWWAF_BAN_RESPONSE: "429"
+            SWWAF_LIMIT_BAN_DURATION: 30m
+        volumes:
+            - servewaf-state:/var/lib/smallwebwaf
+
+volumes:
+    servewaf-state:
+```
+
+### In front of gitea
+
+gitea behind traefik, set up for a code forge:
+
+- the upload limits raised, in size and in time;
+- the response size limit raised, for clones over 1 GiB;
+- the Actions runners exempt from counting;
+- the default request and byte limits kept.
+
+`traefik` is the network traefik is on, made outside this file.
+
+```yaml
+services:
+    gitea:
+        # gitea 1.27.3, 2026-08-29
+        image: gitea/gitea@sha256:87a67ee09d3ae0d1df5fda5dcda3e2a1f9236a45b0a59025d6e00e46adc43bef
+        environment:
+            GITEA__server__ROOT_URL: https://git.example/
+            # The host and the port of the SSH clone URLs gitea shows.
+            GITEA__server__SSH_DOMAIN: git.example
+            GITEA__server__SSH_PORT: "2222"
+            # gitea's TCP peer is rproxy, on the private network.
+            GITEA__security__REVERSE_PROXY_TRUSTED_PROXIES: 10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
+        volumes:
+            - gitea-data:/data
+        networks:
+            - site
+        ports:
+            # SSH does not pass through smallwebwaf.
+            - "2222:22"
+
+    rproxy:
+        image: smallwebwaf
+        environment:
+            SWRP_WAF_BACKEND: http://servewaf:8080
+            SWRP_UPSTREAM_URL: http://gitea:3000
+            # Pushes, LFS objects and image layers over 100 MiB, or slower
+            # than a minute, are cut off at the defaults.
+            SWRP_MAX_REQUEST_SIZE: 2G
+            SWRP_MAX_REQUEST_TIME_MS: "600000"
+            # A clone larger than 1 GiB is cut off at the default.
+            SWRP_MAX_RESPONSE_SIZE: 4G
+        networks:
+            - site
+            - traefik
+        labels:
+            traefik.enable: "true"
+            # rproxy is on two networks; traefik reaches it on this one.
+            traefik.docker.network: traefik
+            traefik.http.routers.git.rule: Host(`git.example`)
+            traefik.http.routers.git.entrypoints: websecure
+            traefik.http.routers.git.tls.certresolver: letsencrypt
+            traefik.http.services.git.loadbalancer.server.port: "8080"
+
+    servewaf:
+        image: smallwebwaf
+        environment:
+            SMALLWEBWAF_COMMAND: servewaf
+            SWWAF_INSTANCE_NAME: fsn1/servewaf
+            # The Actions runners ask for work all day; never count them.
+            SWWAF_RATE_LIMIT_EXEMPT_NETS: 10.0.4.0/24
+            # gitea never serves these; a request for one bans the client.
+            SWWAF_TRAP_PATHS: /wp-login.php,/xmlrpc.php,/wp-admin/
+        volumes:
+            - servewaf-state:/var/lib/smallwebwaf
+        networks:
+            - site
+
+networks:
+    site:
+    traefik:
+        external: true
+
+volumes:
+    gitea-data:
+    servewaf-state:
+```
+
+`deploy/gitea` holds a complete setup of gitea, traefik included, as a Docker
+Compose file. [`docs/gitea.md`](docs/gitea.md) explains it, and records what the
+defaults do in front of gitea, request by request.
+
+### `rproxy` beside the app
+
+The app is built on the `smallwebwaf` image, with `rproxy` inside its container.
+`app/` holds the `Dockerfile` and `app.run` from "`rproxy` in the app's
+container". `rproxy` answers `503` to every request while `servewaf` is down,
+and `servewaf`:
+
+- observes before it enforces;
+- looks addresses up in a local database rather than GeoJS;
+- sends alerts to ntfy;
+- reads its ntfy token from a file.
+
+```yaml
+services:
+    app:
+        # A Dockerfile built FROM the smallwebwaf image, with rproxy inside.
+        build: ./app
+        environment:
+            SWRP_WAF_BACKEND: http://servewaf:8080
+            # Answer 503 rather than pass a request on while servewaf is down.
+            SWRP_DEFAULT_DISPOSITION: deny
+        ports:
+            - "8080:8080"
+
+    servewaf:
+        image: smallwebwaf
+        environment:
+            SMALLWEBWAF_COMMAND: servewaf
+            SWWAF_INSTANCE_NAME: fsn1/servewaf
+            # Refuse nothing yet; log what enforce mode would have done.
+            SWWAF_MODE: observe
+            # Look addresses up in a local IPinfo Lite database, never GeoJS.
+            SWWAF_LOOKUP_SOURCE: file
+            SWWAF_LOOKUP_DB_PATH: /var/lib/ipinfo/ipinfo_lite.mmdb
+            # Alerts to an ntfy topic, with its token read from a file.
+            SWWAF_ALERT_NTFY_URL: https://ntfy.example/smallwebwaf
+            SWWAF_ALERT_NTFY_TOKEN_FILE: /etc/smallwebwaf/tokens/ntfy
+            SWWAF_ALERT_EVENTS: ban,permanent_ban,waf_block,source_failure,file_error
+        volumes:
+            - servewaf-state:/var/lib/smallwebwaf
+            - /srv/ipinfo:/var/lib/ipinfo:ro
+            - /srv/smallwebwaf/tokens:/etc/smallwebwaf/tokens:ro
+
+volumes:
+    servewaf-state:
+```
+
+The database is mounted by its directory, not by file, so that a replaced
+database is seen. A token file belongs to uid 65532, the `smallwebwaf` user,
+with mode `0400`. This one holds an access token the ntfy server issued, which
+`ntfy token add <user>` prints there:
+
+```sh
+mkdir -p /srv/smallwebwaf/tokens
+# <token> is the access token that ntfy printed.
+echo '<token>' > /srv/smallwebwaf/tokens/ntfy
+chown 65532:65532 /srv/smallwebwaf/tokens/ntfy
+chmod 0400 /srv/smallwebwaf/tokens/ntfy
+```
+
+## Design
+
+How it works inside. [`SPEC.md`](SPEC.md) gives every rule in full, and why.
+
+### What happens to a request
+
+A request goes through these steps, in this order. Once `servewaf` refuses a
+request, the steps after that are skipped, apart from the report, and nothing of
+the request reaches the app.
 
 `rproxy` takes the first two:
 
 1. The health check, `GET /_smallwebwaf/healthz`, is answered at once.
-2. The visitor's address is worked out, and `servewaf` is asked about the
-   request.
+2. The visitor's address is worked out from `X-Forwarded-For`, believed only
+   from `SWRP_TRUSTED_PROXIES`. `rproxy` sends `servewaf` the request as the
+   visitor sent it, with the first 64 KiB of its body.
 
 `servewaf` takes the checks:
 
@@ -231,7 +592,8 @@ gives each step in full, under the same numbers.
 5. The lookup of the client's AS number and country.
 6. The country lists.
 7. The reputation sources.
-8. The client's limit percentage.
+8. The client's limit percentage, from its AS number, its country or a
+   reputation hit.
 9. The rate limits.
 10. The trap paths.
 11. The rule files.
@@ -241,84 +603,113 @@ gives each step in full, under the same numbers.
 
 `rproxy` takes the rest, with `servewaf` counting at the end:
 
-14. The request is passed to the app.
-15. After the answer, `rproxy` sends `servewaf` a report. `servewaf` counts the
-    byte limits and adds the request to the client's history.
+14. The request is passed to the app, streaming.
+15. After the answer, `rproxy` sends `servewaf` a report with the status and the
+    bytes each way. For an allowed request, `servewaf` counts the bytes toward
+    the byte limits and adds the request to the client's history.
 
-A refused visitor is answered with `SWWAF_BAN_RESPONSE`, `403` by default (see
-"Ban lengths, response and scope" in [`SPEC.md`](SPEC.md)). A `block` rule or a
-Core Rule Set match answers `403`. `rproxy` itself answers `405` to a method it
-does not pass on, and the status for a size or time limit, such as `413` for a
-body too large (see "`rproxy`" in [`SPEC.md`](SPEC.md)).
+A refused visitor is answered with `SWWAF_BAN_RESPONSE`. A `block` rule or a
+Core Rule Set match answers `403` and bans nobody, since the Core Rule Set has
+false positives; such refusals count toward `SWWAF_ERROR_BURST_THRESHOLD`
+instead. A request over the header limits of step 12 is answered `431`, and bans
+nobody either. `rproxy` itself answers `405` to a method it does not pass on,
+and the status for a size or time limit, such as `413` for a body too large.
 
-## Settings you are likely to touch
+### Clients and bans
 
-Each setting is an environment variable, read at start. Those of `servewaf`
-start with `SWWAF_`, and those of `rproxy` with `SWRP_`.
-[`docs/settings.md`](docs/settings.md) lists every setting, its default and the
-values it takes. The ones most deployments touch:
+- A client is one IPv4 address or one IPv6 netblock of
+  `SWWAF_IPV6_GROUP_PREFIX`, since one abuser usually controls a whole /64.
+- Each limit is counted over a sliding window with a few integers per client.
+  The table of clients and the table of bans each have a bound
+  (`SWWAF_MAX_TRACKED_CLIENTS`, `SWWAF_MAX_BANS`), so memory is bounded too.
+- A ban refuses every request from its netblock until it ends. Requests refused
+  under a ban count toward no limit. A permanent ban ends only when an admin
+  lifts it.
+- Every ban carries notes: the client's AS number and country, the limit it
+  broke or the rule it matched, the request that caused it, and its earlier
+  bans. An admin adds, keeps or lifts a ban by editing `bans.json` or through
+  the ban endpoints (see [`docs/admin-endpoints.md`](docs/admin-endpoints.md)).
 
-- `SWWAF_MODE=observe`: `servewaf` refuses nothing and makes no ban of its own.
-  A request it would have refused is passed to the app, and its log line says
-  what `enforce` mode would have done. For trying a configuration before
-  enforcing it. The limits of `rproxy` still apply.
-- `SWWAF_ALLOW_NETS`: netblocks you trust, such as your monitoring. Their
-  clients skip `servewaf`'s checks.
-- `SWWAF_RATE_LIMIT_EXEMPT_NETS`: netblocks exempt from rate limiting and the
-  byte limits, such as a machine that talks to the app all day.
-- `SWWAF_TRAP_PATHS`: paths only scanners ask for, such as
-  `/wp-login.php,/xmlrpc.php` in front of a code forge. A request for one bans
-  the client.
-- `SWWAF_WAF_DISABLED_RULES`: Core Rule Set rule ids to switch off when a rule
-  refuses your app's ordinary requests. The log line names the rules a request
-  matched. Keep the six default ids in a list you give (see
-  [`docs/settings.md`](docs/settings.md)).
-- `SWRP_MAX_REQUEST_SIZE` and `SWRP_MAX_REQUEST_TIME_MS`: raise them for an app
-  that takes uploads over 100 MiB or slower than 60 seconds.
-- `SWRP_DEFAULT_DISPOSITION`: `allow` (the default) or `deny`, as above.
-- `SWRP_TRUSTED_PROXIES`: the netblocks whose `X-Forwarded-For` `rproxy`
-  believes, by default the private address ranges.
-- `SWWAF_LOOKUP_SOURCE`: `geojs` (the default), `file` or `off`, as above.
-- `SWWAF_ADMIN_TOKEN` and `SWWAF_METRICS_TOKEN`: switch on the ban endpoints and
-  the metrics, at `servewaf`'s own address.
-- `SWWAF_ALERT_WEBHOOK_URL`, `SWWAF_ALERT_SLACK_WEBHOOK_URL` or
-  `SWWAF_ALERT_NTFY_URL`: where alerts go.
-- `SWWAF_INSTANCE_NAME`: the name in every line `servewaf` logs, and in every
-  alert and metric, such as `fsn1/servewaf`.
+### Attack detection
 
-## Checking that it works
+- The Core Rule Set reads the method, the URL with its query string, and the
+  headers of every request, and no body unless `SWWAF_WAF_BODY_LIMIT` is set. In
+  front of a code forge, bodies carry what people write and publish, which the
+  rules take for attacks.
+- `smallwebwaf` changes the Core Rule Set in six ways so that it lets ordinary
+  requests to a code forge through, such as git over HTTP and sign-in through
+  Git Credential Manager. No setting undoes them; "Attack detection" in
+  [`SPEC.md`](SPEC.md) lists them.
+- Rule files are plain text, one rule to a line, edited by hand and read again
+  while `servewaf` runs. The image ships one file of probes no real visitor
+  sends (see [`docs/rules.md`](docs/rules.md)).
 
-- `docker inspect --format '{{.State.Health.Status}}' <container>` says
-  `healthy` for each container of `smallwebwaf`:
-    - for `rproxy`, once it answers and the app accepts connections, whether or
-      not `servewaf` answers;
-    - for `servewaf`, once it answers.
-- A log line with `"msg":"starting"` gives the version, the address and every
-  setting in effect, with secrets masked.
-- A request to the site through traefik gets the app's answer.
-  `https://<site>/_smallwebwaf/healthz` answers `ok`. `servewaf`'s log lines
-  about the request have `"action":"forward"`.
-- To see a refusal without banning yourself, run `servewaf` with
-  `SWWAF_MODE=observe` and ask for `/.env`. The request reaches the app.
-  `servewaf`'s log lines have `"would_action":"banned"` and
-  `"rule_ids":["env-file"]`. In `enforce` mode the same request bans your
-  address for seven days, and your next request makes the ban permanent. Lift
-  the ban by editing `bans.json` (see "Bans" in [`SPEC.md`](SPEC.md)).
-- With `SWWAF_METRICS_TOKEN` set, this answers with the metrics, from a host on
-  `servewaf`'s network:
-  `curl -H "Authorization: Bearer $TOKEN" http://servewaf:8080/_smallwebwaf/metrics`.
-- `make example-app` builds the image and the example app on it, runs the app
-  with `rproxy` in its container and `servewaf` in another, and checks them. It
-  needs network access. It checks:
-    - the health checks;
-    - a request passed to the app;
-    - a ban for a broken limit, and a ban for a probe made permanent;
-    - that only `servewaf`'s container changes the state directory's owner;
-    - with `servewaf` stopped, the app still answering through `rproxy`;
-    - with `servewaf` started again, bans applying again;
-    - orderly stops with `sv stop` and `docker stop`;
-    - bans surviving a new container on the same volume;
-    - a setting given as a file.
+### State files
+
+`servewaf` keeps everything in memory, and the five JSON files in
+`SWWAF_STATE_DIR` hold a copy: `bans.json`, `clients.json`, `lookups.json`,
+`reputation.json` and `alerts.json`. Each is written whole, to a temporary file
+renamed over the real one, so a crash leaves a complete file. `servewaf` notices
+a file edited on disk and takes the edit in; an edit that does not parse is set
+aside as `<name>.bad`, and never stops the running process (see
+[`docs/state-files.md`](docs/state-files.md)).
+
+### The image and its processes
+
+- The image is built on Ubuntu 26.04 LTS, pinned by digest. Its Ubuntu packages
+  come from Ubuntu's archive, and nixpkgs is fixed at one release. An app's
+  `Dockerfile` installs a package with `nix-env -iA nixpkgs.<name>` and gets the
+  same package each time it is built (see [`docs/image.md`](docs/image.md)).
+- runit, a service supervisor, runs `smallwebwaf` as the `smallwebwaf` user (uid
+  and gid 65532) and starts it again when it exits. The `run` script of
+  `servewaf` gives the state directory to the `smallwebwaf` user at each start,
+  so a volume needs no change of owner.
+- `rproxy` and `servewaf` use no token between them. `servewaf`'s own endpoints,
+  under `/_smallwebwaf/`, are for your admin tools and your metrics collector,
+  at its own address on the private network; nothing routes the internet there.
+- `docker stop` gives requests in progress five seconds to finish. With `rproxy`
+  in the app's container, the app must keep answering for five seconds after
+  `SIGTERM` for that to help them.
+- Only faults found at start stop a process: an invalid setting, a rule file or
+  state file that does not parse, a lookup database that cannot be read, or an
+  address it cannot listen on. Once running, a failing lookup service,
+  reputation source or alert destination never takes `servewaf` down.
+
+### Packages
+
+- `cmd/smallwebwaf`: the binary, which only calls `internal/smallwebwaf`.
+- `internal/smallwebwaf`: the process, as the command it is given, and the
+  health check.
+- `internal/config`: reads the settings, the one place they are read.
+- `internal/rproxy`: the reverse proxy in front of one app.
+- `internal/servewaf`: `servewaf`'s server, which runs the checks and answers
+  its own endpoints.
+- `internal/ratelimit`, `internal/bans`, `internal/rules`, `internal/waf`,
+  `internal/lookup`, `internal/reputation`, `internal/anomaly` and
+  `internal/alerts`: one check or source each.
+- `internal/state`, `internal/requestlog`, `internal/remotelog` and
+  `internal/metrics`: the state files, the log lines, the syslog sender and the
+  metrics.
+
+## Rationale
+
+Small self-hosted sites receive a great deal of traffic nobody asked for:
+
+- scrapers that ignore `robots.txt` and crawl every commit of every repository
+  on a public git server;
+- scanners walking through lists of WordPress and `.env` paths;
+- credential-guessing bots.
+
+Most of it comes from a small number of hosting networks and countries. A
+single-person operation has no abuse desk and no CDN contract. It needs
+something small that can be put in front of its services and left alone.
+
+The existing tools each solve part of this. Rule-based firewalls catch attack
+payloads but do not limit request rates. Rate limiters count requests but cannot
+tell a residential visitor from a rented server farm. The products that do most
+of it want a database and a web console. None of them can say "clients from
+these networks are banned after half as many requests as anyone else".
+[`EVALUATION.md`](EVALUATION.md) goes through the candidates one by one.
 
 ## Entrypoints
 
@@ -366,83 +757,32 @@ on the host.
     - `servewaf` listens on port 8090;
     - its state files go in `bin/state`;
     - its rule files are those of `share/rules.d`.
-- `script/example-app`: builds the image and the example app on it, runs them
-  with a volume, and checks them as "Checking that it works" above describes.
-  Then it removes the containers, the network, the volumes and the images. Needs
-  network access. `make example-app`.
+- `script/example-app`: builds the image and the example app
+  (`deploy/example-app`) on it, runs the app with `rproxy` in its container and
+  `servewaf` in another, and checks them. Then it removes the containers, the
+  network, the volumes and the images. Needs network access. `make example-app`.
+  It checks:
+    - the health checks;
+    - a request passed to the app;
+    - a ban for a broken limit, and a ban for a probe made permanent;
+    - that only `servewaf`'s container changes the state directory's owner;
+    - with `servewaf` stopped, the app still answering through `rproxy`;
+    - with `servewaf` started again, bans applying again;
+    - orderly stops with `sv stop` and `docker stop`;
+    - bans surviving a new container on the same volume;
+    - a setting given as a file.
 - `script/gitea-requests`: builds the image and runs gitea 1.27.3 behind
   `rproxy` and `servewaf`, three containers on one network. Every setting is at
-  its default, but for those that join the containers and the header that labels
-  each request. It sends through them a sample of gitea's ordinary use and the
-  requests the Core Rule Set is known to refuse, and prints what `servewaf` did
-  with each. Needs network access, and a docker daemon that pushes to a registry
-  on `localhost` over plain HTTP. [`docs/gitea.md`](docs/gitea.md) records the
-  results. `make gitea-requests`.
-
-## Rationale
-
-Small self-hosted sites receive a great deal of traffic nobody asked for:
-
-- scrapers that ignore `robots.txt` and crawl every commit of every repository
-  on a public git server;
-- scanners walking through lists of WordPress and `.env` paths;
-- credential-guessing bots.
-
-Most of it comes from a small number of hosting networks and countries. A
-single-person operation has no abuse desk and no CDN contract. It needs
-something small that can be put in front of its services and left alone.
-
-The existing tools each solve part of this. Rule-based firewalls catch attack
-payloads but do not limit request rates. Rate limiters count requests but cannot
-tell a residential visitor from a rented server farm. The products that do most
-of it want a database and a web console. None of them can say "clients from
-these networks are banned after half as many requests as anyone else". That is
-the useful thing to say when nearly all abuse comes from a known list of AS
-numbers. [`EVALUATION.md`](EVALUATION.md) goes through the candidates one by
-one.
-
-`smallwebwaf` fills that gap with:
-
-- per-client limits that ban;
-- lower limits for the networks and countries abuse comes from;
-- bans that grow with repetition;
-- a log that is easy to search and ship;
-- a site that keeps answering while the part that decides is down;
-- one binary, with no database and one required setting.
-
-## Design
-
-The `smallwebwaf` image is built on Ubuntu 26.04 LTS, pinned by digest, with
-nixpkgs fixed at one release. An app's `Dockerfile` installs a package with
-`nix-env -iA nixpkgs.<name>` and gets the same package each time it is built.
-[`docs/image.md`](docs/image.md) lists what the image holds and how each part is
-pinned.
-
-- runit, a service supervisor, runs `smallwebwaf` and starts it again when it
-  exits. In an app's image built on the `smallwebwaf` image, it runs `rproxy`
-  and the app side by side, each as its own user.
-- `rproxy` listens on port 8080 and passes requests to the app at
-  `SWRP_UPSTREAM_URL`. It answers the health check itself, and the refusals and
-  errors "`rproxy`" in [`SPEC.md`](SPEC.md) lists.
-- `servewaf` listens on port 8080 of its own container. Nothing should route the
-  internet there. Its own endpoints, under `/_smallwebwaf/`, are for your admin
-  tools and your metrics collector.
-- `rproxy` and `servewaf` use no token between them. Anything on their private
-  network can ask `servewaf` a question, or send it a report.
-- The app sees the headers traefik sent, with traefik's address added to
-  `X-Forwarded-For`, from a TCP peer that is `rproxy`. So the app must trust
-  `rproxy`'s address for forwarded headers. With `rproxy` in the app's
-  container, that address is `127.0.0.1` or `::1`, which the private address
-  ranges leave out.
-- The state files live in `/var/lib/smallwebwaf` in `servewaf`'s container. A
-  volume mounted there keeps them across a deploy.
-- `docker stop` gives requests in progress five seconds to finish. With `rproxy`
-  in the app's container, the app must keep answering for five seconds after
-  `SIGTERM` for that to help them.
-
-"Deployment" in [`SPEC.md`](SPEC.md) has the rest: the health checks, what
-happens when a process stops, moving a port, and the forwarded headers.
-"Architecture" in [`SPEC.md`](SPEC.md) lists the packages and what each does.
+  its default, but for those that join the containers and
+  `SWWAF_LOG_REQUEST_HEADERS`, which adds the header that labels each request.
+  It sends through them a sample of gitea's ordinary use and the requests the
+  Core Rule Set is known to refuse, and prints what `servewaf` did with each.
+  Needs network access, and a docker daemon that pushes to a registry on
+  `localhost` over plain HTTP. `make gitea-requests`.
+- `script/gitea-setup`: builds the image, brings up the setup in `deploy/gitea`,
+  and checks it as [`docs/gitea.md`](docs/gitea.md) describes. Then it removes
+  the containers, the network, the volumes and the image it built. Needs network
+  access. `make gitea-setup`.
 
 ## TODO
 
@@ -455,8 +795,7 @@ happens when a process stops, moving a port, and the forwarded headers.
 - [`EVALUATION.md`](EVALUATION.md): what already exists, what each tool covers
   and misses, and why none was adopted.
 - [`REPO_POLICIES.md`](REPO_POLICIES.md): the policies this repository follows.
-- [`docs/settings.md`](docs/settings.md): every setting, its default and the
-  values it takes.
+- [`docs/settings.md`](docs/settings.md): every setting and the values it takes.
 - [`docs/rules.md`](docs/rules.md): the rule file format and the default file.
 - [`docs/admin-endpoints.md`](docs/admin-endpoints.md): the endpoints under
   `/_smallwebwaf/`, with examples.
@@ -467,7 +806,8 @@ happens when a process stops, moving a port, and the forwarded headers.
 - [`docs/state-files.md`](docs/state-files.md): the state files and what each
   holds.
 - [`docs/image.md`](docs/image.md): what the image holds and how it is pinned.
-- [`docs/gitea.md`](docs/gitea.md): `smallwebwaf` in front of gitea.
+- [`docs/gitea.md`](docs/gitea.md): `smallwebwaf` in front of gitea: the setup
+  in `deploy/gitea`, and what the defaults do there.
 
 ## License
 

SPEC.md

@@ -66,10 +66,10 @@ to them.
       one it does not know, the binary prints the commands and exits with
       status 2.
     - `internal/config`: reads the settings, the one place they are read.
-    - `internal/proxy`: `servewaf`'s server. It runs the checks in `check`, and
-      holds `servewaf`'s question, answer and report. It answers `servewaf`'s
-      own endpoints in `answerOwnEndpoint`. It counts bytes, refusals and
-      anomalies, and writes the log lines.
+    - `internal/servewaf`: `servewaf`'s server. It runs the checks in `check`,
+      and holds `servewaf`'s question, answer and report. It answers
+      `servewaf`'s own endpoints in `answerOwnEndpoint`. It counts bytes,
+      refusals and anomalies, and writes the log lines.
     - `internal/rproxy`: the reverse proxy in front of one app that asks
       `servewaf` about each request. It passes a request to the app with the
       standard library's `httputil.ReverseProxy`, within the time and size
@@ -123,7 +123,9 @@ runs steps 3 to 13, and does the counting of step 15. The first step that
 produces a final answer ends the checks. Step 15 runs for each request
 `servewaf` answers with `allow`, `deny` or `close`. `rproxy`'s size and time
 limits apply to the whole exchange. Each step names the section that holds its
-rules.
+rules. Each check is a heuristic. Its name, in parentheses below, is the value
+of the request log's `heuristic` field. `refusal_limit` and `byte_limits` give
+theirs in `after_answer_heuristic` instead.
 
 1. `GET /_smallwebwaf/healthz` is answered at once by `rproxy`, before any
    check, so a health checker never needs an exemption and is never refused.
@@ -141,9 +143,9 @@ rules.
       around its address, a /64 by default, since one abuser usually controls a
       whole /64. A client is therefore one IPv4 address or one IPv6 group.
 3. The static lists. A client in `SWWAF_ALLOW_NETS` skips steps 4 to 12, the
-   byte limits and the error burst. A client in `SWWAF_DENY_NETS` is refused; a
-   client in both lists is let through.
-4. Bans. A client under a ban is refused (see "Bans").
+   byte limits and the error burst. A client in `SWWAF_DENY_NETS` is refused
+   (`deny_nets`); a client in both lists is let through.
+4. Bans. A client under a ban is refused (`active_ban`; see "Bans").
 5. The lookup, unless `SWWAF_LOOKUP_SOURCE` is `off` (see "Lookup of AS number
    and country"). The request goes on at once. It waits for the first GeoJS
    answer, up to `SWWAF_LOOKUP_TIMEOUT`, only when one of these needs it:
@@ -153,22 +155,26 @@ rules.
 
     A request that ends before the answer comes is logged without it.
 
-6. The country lists (see "Country lists").
-7. The reputation sources (see "Reputation"). A client on a fetched blocklist
-   gets `SWWAF_BLOCKLIST_ACTION`. A client on the CrowdSec decision list is
-   banned. A client listed by a DNS blocklist, or scored at least
-   `SWWAF_ABUSEIPDB_MIN_SCORE` by AbuseIPDB, gets `SWWAF_REPUTATION_ACTION`.
+6. The country lists (`countries`; see "Country lists").
+7. The reputation sources (see "Reputation"), in this order:
+    - A client on a fetched blocklist gets `SWWAF_BLOCKLIST_ACTION`
+      (`blocklists`).
+    - A client on the CrowdSec decision list is banned (`crowdsec`).
+    - A client listed by a DNS blocklist gets `SWWAF_REPUTATION_ACTION`
+      (`dnsbl`).
+    - A client scored at least `SWWAF_ABUSEIPDB_MIN_SCORE` by AbuseIPDB gets
+      `SWWAF_REPUTATION_ACTION` (`abuseipdb`).
 8. The client's limit percentage (see "Biased thresholds").
-9. Rate limiting (see "Request rate limits, per client"). A request over a limit
-   times the percentage is refused and bans the client.
-10. The trap paths (see "Attack detection"). A request for one is refused and
-    bans the client.
-11. The rule files (see "Rule files"). Matching stops at the first rule that
-    refuses.
-12. The header limits (see "Answering in time"), and then the Core Rule Set (see
-    "Attack detection"). A Core Rule Set match is refused with `403` while
-    `SWWAF_WAF_MODE` is `block`, and only logged and alerted while it is
-    `detect`.
+9. Rate limiting (`rate_limits`; see "Request rate limits, per client"). A
+   request over a limit times the percentage is refused and bans the client.
+10. The trap paths (`trap_paths`; see "Attack detection"). A request for one is
+    refused and bans the client.
+11. The rule files (`rule_files`; see "Rule files"). Matching stops at the first
+    rule that refuses.
+12. The header limits (`header_limits`; see "Answering in time"), and then the
+    Core Rule Set (`core_rule_set`; see "Attack detection"). A Core Rule Set
+    match is refused with `403` while `SWWAF_WAF_MODE` is `block`, and only
+    logged and alerted while it is `detect`.
 13. A path under `/_smallwebwaf/` is answered `404`, so that the app never sees
     that prefix.
 14. `rproxy` passes the request to `SWRP_UPSTREAM_URL`, streaming (see "Passing
@@ -182,14 +188,14 @@ rules.
       are added to the byte counters, as `SWWAF_BYTES_COUNT` says. For a
       WebSocket, what it carried each way counts once it closes. A client whose
       total passes a byte limit times the percentage has broken that limit and
-      is banned. The response in progress is not cut off.
+      is banned (`byte_limits`). The response in progress is not cut off.
     - For a request it allowed, the client's history and the anomaly counters
       are updated, and the alert thresholds are evaluated.
 
     For a request it refused, `servewaf` adds nothing to the byte limits. It
     updates the history and the anomaly counters at its decision. It counts the
-    refusals the error burst counts at the decision too (see "Attack
-    detection").
+    refusals the error burst counts at the decision too (`refusal_limit`; see
+    "Attack detection").
 
 In `SWWAF_MODE=observe`, every refusal above is logged as what would have
 happened, nothing is refused, and `servewaf` makes no ban of its own. A path
@@ -397,32 +403,31 @@ Conventions:
 
 ### Request rate limits, per client
 
-Breaking one bans the client. The defaults suit programmatic use of an API, such
-as an automation fleet on another host, and still stop abusive bots. A fleet of
-20 agents, each making a request every 10 seconds at its busiest, makes 120
-requests a minute and 7,200 an hour. Working around the clock, it makes 172,800
-a day. It stays under all three limits.
+Breaking one bans the client. The defaults let people read a site and stop
+scrapers that send many requests slowly over hours or days. The hour limit is
+the main one.
 
-- Per minute: 500, about 8 requests a second. It leaves room for the fleet's 120
-  a minute and a few quick first visits with an empty cache. A gitea page opened
-  with an empty cache loads about 40 files. A client firing requests as fast as
-  it can passes the limit within seconds.
-- Per hour: 20,000, about 5.5 requests a second for a whole hour. A client that
-  keeps up 6 a second makes 21,600 in an hour, and passes it, at 360 a minute,
-  under the minute limit. The fleet's 7,200 an hour is about a third of it.
-- Per day: 300,000, about 3.5 requests a second around the clock. A scraper that
-  keeps up 4 a second makes 345,600 a day, and passes it. At 240 a minute and
-  14,400 an hour, it stays under the other two limits.
+- Per minute: 120, 2 requests a second. It leaves room for a person opening two
+  pages at once with an empty cache. A gitea page opened with an empty cache
+  loads 20 to 60 files, and a handful once cached.
+- Per hour: 1,500. A person reading code in gitea for a whole hour, a page every
+  20 seconds, makes about 900 requests. A scraper making one request every 2
+  seconds makes 1,800 an hour, more than the limit.
+- Per day: 6,000, four hours at the hour limit. A scraper making one request
+  every 10 seconds makes 8,640 a day, more than the limit.
 
-Counting cannot catch a client that stays under all three limits, such as one
-that keeps up 3 requests a second. Only the other checks can catch an abuser
+Counting cannot catch a client that stays under all three limits, about 4
+requests a minute around the clock. Only the other checks can catch an abuser
 that slow. They include the trap paths, the rule files, the Core Rule Set and
-the blocklists. An abuser that trips none of them is not caught. A machine that
-keeps up more than 500 requests a minute passes the minute limit. One that keeps
-up more than about 5.5 a second for an hour passes the hour limit. One that
-keeps up more than about 3.5 a second all day passes the day limit, as two busy
-Actions runners on one address do. Such a machine's address belongs in
-`SWWAF_RATE_LIMIT_EXEMPT_NETS`.
+the blocklists. An abuser that trips none of them is not caught.
+
+Some legitimate clients pass the limits:
+
+- An Actions runner asks gitea for work all day and can pass the limits.
+- Everyone behind one shared address, such as an office, shares one client's
+  limits.
+
+Their addresses belong in `SWWAF_RATE_LIMIT_EXEMPT_NETS`.
 
 `SWWAF_RATE_LIMIT_EXEMPT_PATHS` takes path prefixes out of the count, such as
 static assets or health checks; their bytes are not counted either. A prefix is
@@ -435,12 +440,10 @@ matched the same way.
 
 ### Byte limits, per client
 
-The hour and day limits sit about twice above what 40 people busy with heavy web
-apps move together on one address. Each moves about 256 MiB an hour, for ten
-hours a day. A response's bytes are counted when it ends (see step 15). So the
-minute limit holds three of the largest responses, with their requests, ending
-in the same minute. No single download then breaks a limit. An operator who
-raises `SWRP_MAX_RESPONSE_SIZE` must raise the byte limits too.
+By default there is no minute limit, so a client can download in a burst at full
+speed. The hour limit defaults to 50 GiB and the day limit to 100 GiB. They
+allow several downloads of a few GiB each. A response's bytes are counted when
+it ends (see step 15).
 
 ### Lookup of AS number and country
 
@@ -1544,20 +1547,11 @@ It sets no `ENTRYPOINT` or `USER` of its own. The container must start
 
 - The image is Ubuntu's newest long-term support release, pinned by digest, and
   moves to the next LTS release when that ships. Its packages come from Ubuntu's
-  snapshot service, the archive as it was at the moment the Dockerfile names,
-  rather than the live archive, whose packages change with every update. The
-  snapshot is never older than the pinned Ubuntu image, since older packages can
-  need older versions of packages the image holds, and it moves forward with the
-  image's digest. The Dockerfile names the hash of each of the snapshot's
-  `InRelease` files, which cover every package list and so every package, and
-  the build checks them before installing. The live archive's `InRelease` files,
-  which `apt-get update` also fetches and the install does not use, are left out
-  of the check. The hashes are the amd64 archive's, so the image is built for
-  amd64 only.
+  archive, whose packages change with every update.
 - The Ubuntu image has no CA certificates. Without them Nix cannot download
   packages and `servewaf` cannot reach GeoJS, so `ca-certificates` is installed
-  by name. The snapshot itself is fetched over HTTPS with the CA certificates of
-  the Go image that builds `smallwebwaf`, itself pinned by digest.
+  by name. apt fetches the packages over plain HTTP and checks each one against
+  the archive's signed package lists, so the install needs no CA certificates.
 - nixpkgs comes from a release file on `releases.nixos.org`, named with its
   hash, not from a GitHub archive, whose bytes can change. Root uses Nix
   directly; no Nix daemon runs. `nix-bin` creates no build users, so
@@ -1575,12 +1569,13 @@ It sets no `ENTRYPOINT` or `USER` of its own. The container must start
   writes. `runsvinit` starts runit's `runsvdir`, which runs the `run` script of
   each directory under `/etc/service`. Ubuntu's `sv` looks for services there
   too.
-- The image's `run` script, `/etc/service/smallwebwaf/run`, starts the command
-  `SMALLWEBWAF_COMMAND` names, `rproxy` when it is unset or empty, as the
-  `smallwebwaf` user (uid and gid 65532) with runit's `chpst`. For `servewaf`,
-  it first makes `SWWAF_STATE_DIR` and every file in it belong to that user. For
-  `rproxy` it changes no owner. With any other value, `smallwebwaf` prints its
-  commands and exits, and the health check fails.
+- The image's `run` script is `/etc/service/smallwebwaf/run`. It starts
+  `servewaf` when `SMALLWEBWAF_COMMAND` is `servewaf`, and `rproxy` when it is
+  `rproxy`, unset or empty. It runs either as the `smallwebwaf` user (uid and
+  gid 65532), with runit's `chpst`. For `servewaf`, it first makes
+  `SWWAF_STATE_DIR` and every file in it belong to that user. For `rproxy` it
+  changes no owner. With any other value, it starts nothing, and stops with a
+  message naming `SMALLWEBWAF_COMMAND` and its value.
 
 Every `run` script, the app's included, is a bash script. It starts with
 `#!/usr/bin/env bash` and `set -euo pipefail`, and puts its code in a `main`
@@ -1629,10 +1624,13 @@ says what it checks:
 - With `SMALLWEBWAF_COMMAND=servewaf`, it passes while `servewaf` answers
   `GET /_smallwebwaf/healthz` on `127.0.0.1`, at the port in
   `SWWAF_LISTEN_ADDR`.
-- Otherwise it passes while `rproxy` answers that request on `127.0.0.1`, at the
-  port in `SWRP_LISTEN_ADDR`, and the app accepts connections at
-  `SWRP_UPSTREAM_URL`. It does not ask `servewaf`, so that the site stays in
-  traefik's routes while `servewaf` is down.
+- With `SMALLWEBWAF_COMMAND` unset, empty or `rproxy`, it passes while `rproxy`
+  answers that request on `127.0.0.1`, at the port in `SWRP_LISTEN_ADDR`, and
+  the app accepts connections at `SWRP_UPSTREAM_URL`. It does not ask
+  `servewaf`, so that the site stays in traefik's routes while `servewaf` is
+  down.
+- With any other value, it fails with a message naming `SMALLWEBWAF_COMMAND` and
+  its value.
 
 traefik sends a container no requests until it shows as healthy. So the check
 runs every second from the container's start until it first passes, for up to a
@@ -1697,15 +1695,14 @@ ranges traefik is on.
 
 ### upaas
 
-An app deployed by upaas, which rebuilds and restarts an app's Docker container
-when its repository changes, takes the shape of "`rproxy` in the app's
-container" with no change to upaas. upaas builds the app's Dockerfile and runs
-the one container as it runs any app. The traefik labels route to port 8080, and
-the `SWRP_` settings go with the app's environment variables. `servewaf` runs in
-a container of its own, on a network the app's container can reach, with its
-state volume and the directory of any token file. `docs/gitea.md` records what
-the defaults do in front of gitea, and `script/gitea-requests` checks those
-notes.
+upaas rebuilds and restarts an app's Docker container when its repository
+changes. An app it deploys takes the shape of "`rproxy` in the app's container"
+with no change to upaas. upaas builds the app's Dockerfile and runs the one
+container as it runs any app. The traefik labels route to port 8080, and the
+`SWRP_` settings go with the app's environment variables. `servewaf` runs in a
+container of its own, on a network the app's container can reach, with its state
+volume and the directory of any token file. `docs/gitea.md` records what the
+defaults do in front of gitea, and `script/gitea-requests` checks those notes.
 
 ## Planned, not built
 

deploy/gitea/compose.yaml

@@ -0,0 +1,135 @@
+# Gitea behind traefik, with rproxy and servewaf in front of it.
+# docs/gitea.md says what each setting here does and why. Before starting it:
+#   - set SMALLWEBWAF_IMAGE to the smallwebwaf image, named by digest;
+#   - replace git.example.org with the site's host name;
+#   - replace each 10.99.0 with the first three numbers of a /24 subnet that
+#     no other network on the host uses. The /24 must lie inside 10.0.0.0/8,
+#     172.16.0.0/12 or 192.168.0.0/16, because rproxy believes
+#     X-Forwarded-For only from those by default. Replace each fd10:99 with
+#     the first two hextets of an unused /64 subnet whose third and fourth
+#     hextets are 0, as in fd10:99::/64;
+#   - set GITEA_SECRET_KEY to the output of
+#     `docker run --rm <gitea's image below> gitea generate secret SECRET_KEY`,
+#     once per install, and keep it.
+# Then run `docker compose up --detach` in this directory.
+# script/gitea-setup checks this setup.
+
+name: gitea
+
+x-logging: &logging
+    driver: json-file
+    options:
+        max-size: 10m
+        max-file: "5"
+
+services:
+    traefik:
+        # traefik v3.7.17, 2026-11-03
+        image: traefik@sha256:68ae5fe5b64ca166704b746a9e8afcd385e36b3f569a5691401bf652d57b3748
+        # traefik replaces the X-Forwarded-For header a visitor sends. Keep it
+        # so: otherwise a visitor could name an address on the shared network,
+        # and skip servewaf's checks.
+        command:
+            - --providers.docker.exposedbydefault=false
+            - --entrypoints.web.address=:80
+            - --entrypoints.web.http.redirections.entrypoint.to=websecure
+            - --entrypoints.websecure.address=:443
+            # Until a certificate resolver is added here, as for your other
+            # sites, traefik answers with a certificate it made itself.
+            - --entrypoints.websecure.http.tls=true
+            # traefik's own limit of 60 seconds for a whole request would cut
+            # off an upload long before rproxy's limit of 30 minutes.
+            - --entrypoints.websecure.transport.respondingTimeouts.readTimeout=30m
+        ports:
+            - 80:80
+            - 443:443
+        volumes:
+            - /var/run/docker.sock:/var/run/docker.sock:ro
+        networks:
+            shared:
+                # Containers on the shared network find traefik under the
+                # site's name, and so reach it from their own address.
+                aliases:
+                    - git.example.org
+        restart: unless-stopped
+
+    gitea:
+        # gitea 1.27.3, 2026-08-29
+        image: gitea/gitea@sha256:87a67ee09d3ae0d1df5fda5dcda3e2a1f9236a45b0a59025d6e00e46adc43bef
+        environment:
+            GITEA__server__ROOT_URL: https://git.example.org/
+            # Gitea starts at its defaults, with SQLite, instead of showing its
+            # install page to whoever opens it first.
+            GITEA__security__INSTALL_LOCK: "true"
+            GITEA__security__SECRET_KEY: ${GITEA_SECRET_KEY:?set GITEA_SECRET_KEY, see docs/gitea.md}
+            # Accounts are made with `gitea admin user create`.
+            GITEA__service__DISABLE_REGISTRATION: "true"
+            # rproxy's addresses. Gitea then takes each visitor's address from
+            # the X-Real-Ip header traefik sets and rproxy passes on.
+            GITEA__security__REVERSE_PROXY_TRUSTED_PROXIES: 10.99.0.2,fd10:99::2
+        volumes:
+            - gitea-data:/data
+        networks:
+            - shared
+        restart: unless-stopped
+
+    rproxy:
+        image: ${SMALLWEBWAF_IMAGE:?set SMALLWEBWAF_IMAGE to the smallwebwaf image}
+        environment:
+            SWRP_WAF_BACKEND: http://servewaf:8080
+            SWRP_UPSTREAM_URL: http://gitea:3000
+            # Pushes, LFS objects, packages and release attachments of up to
+            # 2 GiB, sent in up to 30 minutes.
+            SWRP_MAX_REQUEST_SIZE: 2G
+            SWRP_MAX_REQUEST_TIME_MS: "1800000"
+            # 15 minutes for a clone or a download, half the default.
+            SWRP_MAX_RESPONSE_TIME_MS: "900000"
+        labels:
+            traefik.enable: "true"
+            traefik.http.routers.gitea.rule: Host(`git.example.org`)
+            traefik.http.routers.gitea.entrypoints: websecure
+            traefik.http.services.gitea.loadbalancer.server.port: "8080"
+        networks:
+            shared:
+                ipv4_address: 10.99.0.2
+                ipv6_address: fd10:99::2
+        logging: *logging
+        restart: unless-stopped
+
+    servewaf:
+        image: ${SMALLWEBWAF_IMAGE:?set SMALLWEBWAF_IMAGE to the smallwebwaf image}
+        environment:
+            SMALLWEBWAF_COMMAND: servewaf
+            # The containers on the shared network skip the checks. Add the
+            # address of an automation fleet on another host here too; without
+            # that, it is counted like any client.
+            SWWAF_ALLOW_NETS: 10.99.0.128/25,fd10:99:0:0:8000::/65
+            # In block mode the Core Rule Set refuses everyday Gitea searches
+            # and file names, and 31 refusals in a minute ban the address.
+            SWWAF_WAF_MODE: detect
+        volumes:
+            - servewaf-state:/var/lib/smallwebwaf
+        networks:
+            - shared
+        logging: *logging
+        restart: unless-stopped
+
+networks:
+    # The network traefik and Gitea share. Its containers get addresses in the
+    # upper half of each subnet, which servewaf lets skip the checks. Each
+    # subnet's gateway, the host's own address on it, stays out of that half:
+    # requests docker passes on from a published port can come from it.
+    shared:
+        enable_ipv6: true
+        ipam:
+            config:
+                - subnet: 10.99.0.0/24
+                  ip_range: 10.99.0.128/25
+                  gateway: 10.99.0.1
+                - subnet: fd10:99::/64
+                  ip_range: fd10:99:0:0:8000::/65
+                  gateway: fd10:99::1
+
+volumes:
+    gitea-data:
+    servewaf-state:

docs/gitea.md

@@ -1,51 +1,177 @@
 # smallwebwaf in front of gitea
 
-These notes record what `smallwebwaf` does in front of gitea at the default
-settings. They are observations, not requirements; the requirements are in
-[`SPEC.md`](../SPEC.md). `script/gitea-requests` runs gitea behind `rproxy` and
-`servewaf`, and sends through them a sample of gitea's ordinary use and the
+`deploy/gitea/compose.yaml` runs gitea behind traefik, with `rproxy` and
+`servewaf` in front of it. This document says what that setup sets and why, and
+what the defaults would do without it. [`SPEC.md`](../SPEC.md) says how
+`smallwebwaf` behaves.
+
+## The setup
+
+Four containers share one Docker network, the shared network:
+
+- traefik, which routes the site's HTTPS requests to `rproxy`, and redirects
+  plain HTTP to HTTPS;
+- `rproxy`, in front of gitea;
+- gitea 1.27.3, as its image comes;
+- `servewaf`, with a volume for its state files.
+
+To start it:
+
+1. In `deploy/gitea/compose.yaml`, replace `git.example.org` with the site's
+   host name.
+2. Replace each `10.99.0` with the first three numbers of a `/24` subnet that no
+   other network on the host uses. The `/24` must lie inside `10.0.0.0/8`,
+   `172.16.0.0/12` or `192.168.0.0/16`, because `rproxy` believes
+   `X-Forwarded-For` only from those by default. Replace each `fd10:99` with the
+   first two hextets of an unused `/64` subnet whose third and fourth hextets
+   are 0, as in `fd10:99::/64`.
+3. Set `SMALLWEBWAF_IMAGE` to the `smallwebwaf` image, named by digest.
+4. Set `GITEA_SECRET_KEY` to the output of
+   `docker run --rm <gitea's image> gitea generate secret SECRET_KEY`, with
+   gitea's image as `deploy/gitea/compose.yaml` names it. Do this once per
+   install, and keep the key.
+5. Run `docker compose up --detach` in `deploy/gitea`.
+6. Make gitea's first user with `gitea admin user create`, in gitea's container,
+   as the user `git`.
+
+Sign-up is off: accounts are made with `gitea admin user create`. gitea starts
+at its defaults, with SQLite. traefik answers with a certificate it made itself
+until you add a certificate resolver, as for your other sites. SSH to gitea does
+not pass through `smallwebwaf`; publish gitea's SSH port yourself if you use it.
+
+`make gitea-setup` checks the setup. It builds the image, brings the setup up
+under a name of its own, and checks:
+
+- that a page load, a push and a clone sent through traefik pass through
+  `rproxy`, and that `servewaf` checks them;
+- that gitea logs the visitor's address, not `rproxy`'s;
+- that a request from a container on the shared network skips the checks;
+- that with `servewaf` stopped, gitea still answers through `rproxy`.
+
+## Uploads and downloads
+
+An upload is a request:
+
+- a git push;
+- an LFS object;
+- a container image layer;
+- a package file;
+- a release attachment.
+
+The setup lets an upload of up to 2 GiB, sent in up to 30 minutes, through:
+
+- `SWRP_MAX_REQUEST_SIZE` is `2G`. At the default, an upload over 100 MiB is cut
+  off.
+- `SWRP_MAX_REQUEST_TIME_MS` is `1800000`, 30 minutes. At the default, an upload
+  that takes over 60 seconds is cut off.
+- traefik's `readTimeout` is 30 minutes. traefik's own default of 60 seconds for
+  a whole request would cut off an upload first.
+
+A clone or a download is a response:
+
+- `SWRP_MAX_RESPONSE_TIME_MS` is `900000`, 15 minutes, half the default. A clone
+  or download that takes longer is cut off.
+- `SWRP_MAX_RESPONSE_SIZE` stays at its default, 1 GiB. A repository whose clone
+  is larger needs it raised.
+
+The byte limits stay at their defaults: no minute limit, 50 GiB an hour and 100
+GiB a day.
+
+## The checks
+
+`SWWAF_WAF_MODE` is `detect`. The Core Rule Set then logs a match, with its rule
+ids, and refuses nothing. In `block` mode, the default, it refuses everyday
+gitea searches and file names. The section "What the Core Rule Set refuses in
+`block` mode" below lists them. Each such refusal counts toward the error burst,
+so 31 in one minute ban the address.
+
+Every other check stays at its default. A client may make 120 requests a minute,
+1,500 an hour and 6,000 a day. Archive downloads and blame and history pages are
+what scrapers hammer, and these limits do most of the work there.
+
+## The shared network
+
+Containers on the shared network skip `servewaf`'s checks:
+
+- The shared network's subnets are `10.99.0.0/24` and `fd10:99::/64`. Docker
+  gives its containers addresses in the upper half of each, `10.99.0.128/25` and
+  `fd10:99:0:0:8000::/65`, which `SWWAF_ALLOW_NETS` names.
+- traefik is known on the shared network by the site's host name. So a container
+  there that asks for the site reaches traefik from its own address. An
+  automation fleet in such a container skips the checks.
+- Each subnet's gateway, `10.99.0.1` and `fd10:99::1`, is the host's own address
+  on it. Requests docker passes on from a published port can come from the
+  gateway, so the gateways are left out of `SWWAF_ALLOW_NETS`. The network has
+  IPv6, so a visitor over IPv6 reaches traefik from its own address, and
+  `servewaf` checks it as itself.
+- A container on the shared network that asks for the site at the host's public
+  address arrives from the gateway. It is checked like any visitor.
+- A fleet on another host can have its address added to `SWWAF_ALLOW_NETS`.
+  Without that, it is counted like any client.
+- traefik replaces the `X-Forwarded-For` a visitor sends, by default. Keep it
+  so: otherwise a visitor could name an address on the shared network, and skip
+  the checks.
+- Anything on the shared network can reach gitea and `servewaf` around `rproxy`.
+  Put only containers you trust on it.
+
+## gitea's settings
+
+- `REVERSE_PROXY_TRUSTED_PROXIES` names `rproxy`'s fixed addresses, `10.99.0.2`
+  and `fd10:99::2`. gitea then takes each visitor's address from the `X-Real-Ip`
+  header, which traefik sets and `rproxy` passes on. Without it, gitea logs
+  every visitor as `rproxy`.
+- `INSTALL_LOCK` is `true`, as "The setup" above says.
+
+## Methods
+
+`rproxy` passes on only these methods: `GET`, `HEAD`, `POST`, `OPTIONS`, `PUT`,
+`DELETE`, `PATCH` and `QUERY`. gitea 1.27.3 needs no other. Its routes use:
+
+- pages and the API: `GET`, `HEAD`, `POST`, `PUT`, `PATCH` and `DELETE`;
+- git's push, clone and fetch over HTTP: `GET`, `POST` and `OPTIONS`;
+- LFS: `GET`, `POST` and `PUT`;
+- the container registry and the other package registries: `GET`, `HEAD`,
+  `POST`, `PUT`, `PATCH` and `DELETE`;
+- Actions runners: `POST`.
+
+## The log
+
+`rproxy` and `servewaf` write each query string to the log whole. A token sent
+in the query string, as `?token=`, is then in the log. Send it in the
+`Authorization` header instead.
+
+## Actions runners
+
+A runner on the shared network skips the checks. One on another host is counted
+like any client. A runner older than version 0.4 (April 2026) asks for work
+every 2 seconds, 1,800 requests an hour. While it runs a job, it reports the
+job's log and state every second instead, two requests a second.
+
+So one idle runner makes 1,800 requests an hour, more than the hour limit of
+1,500. A busy one, at two requests a second, passes the minute limit of 120
+within two minutes. Its address is then banned, its running jobs fail, and each
+repeat within a day makes the ban longer. Newer runners ask for work less often.
+Put the runners' addresses in `SWWAF_RATE_LIMIT_EXEMPT_NETS`.
+
+## What the Core Rule Set refuses in `block` mode
+
+These notes record what the Core Rule Set does in front of gitea in `block`
+mode, at the other defaults. They are observations, not requirements.
+`script/gitea-requests` runs gitea behind `rproxy` and `servewaf` at the
+defaults. It sends through them a sample of gitea's ordinary use and the
 requests named below. It reports each request the Core Rule Set refuses, so that
 these notes can be checked again when gitea or the Core Rule Set changes
-version.
+version. In `detect` mode, as the setup runs it, the same requests are logged
+with their rule ids, and pass.
 
-## What the defaults cover
+Each refusal answers only that request ("Bans" in `SPEC.md` says what it counts
+toward). The request log names the rule in `waf_rule_ids`, which
+`SWWAF_WAF_DISABLED_RULES` can switch off.
 
-- SSH access to gitea does not pass through `smallwebwaf` and is not protected
-  by it.
-- A clone is a response. It fits the defaults of 30 minutes and 1 GiB unless the
-  repository is large or the link slow. A repository whose clone is larger than
-  1 GiB needs `SWRP_MAX_RESPONSE_SIZE` raised, and the byte limits with it
-  ("Byte limits, per client" in `SPEC.md`).
-- A push is a request, and so is every other upload:
-    - a git push;
-    - an LFS object;
-    - a container image layer;
-    - a package file;
-    - a release attachment.
+### What it lets through
 
-    At the defaults, an upload larger than 100 MiB or taking more than 60
-    seconds is cut off ("`rproxy`'s limits" in `SPEC.md`). A gitea that takes
-    large uploads needs `SWRP_MAX_REQUEST_SIZE` and `SWRP_MAX_REQUEST_TIME_MS`
-    raised to fit.
-
-- Archive download and blame or history pages are what scrapers hammer. The
-  request limits do most of the work there.
-- An Actions runner that reaches gitea through `smallwebwaf` sends requests all
-  day. One older than version 0.4 (April 2026) asks for work every 2 seconds,
-  43,200 requests a day. While it runs a job, it reports the job's log and state
-  every second instead, two requests a second. So one runner busy all day sends
-  120 requests a minute and 172,800 a day, under the request limits. Two such
-  runners on one address, each busy all day, make 345,600 and pass the day limit
-  of 300,000. Three busy at once make 21,600 an hour and pass the hour limit of
-  20,000. Five busy at once make 600 a minute and pass the minute limit of 500.
-  Their address is then banned, their running jobs fail, and each repeat within
-  a day makes the ban longer. Newer runners ask for work less often. Put the
-  runners' addresses in `SWWAF_RATE_LIMIT_EXEMPT_NETS`.
-
-## What the Core Rule Set lets through
-
-At the defaults, the Core Rule Set lets gitea's ordinary use through, apart from
-the refusals in the next section:
+The Core Rule Set lets gitea's ordinary use through, apart from the refusals in
+the sections after this one:
 
 - browsing and views of files in a repository, with their history, blame and the
   file tree;
@@ -60,12 +186,6 @@ the refusals in the next section:
   editor, code included, since no body is read;
 - the page gitea shows after a change, with its message naming what was done.
 
-## What the Core Rule Set still refuses
-
-Each refusal answers only that request ("Bans" in `SPEC.md` says what it counts
-toward). The request log names the rule in `waf_rule_ids`, which
-`SWWAF_WAF_DISABLED_RULES` can switch off.
-
 ### A query string that reads as an attack
 
 Most often this is a search. A search term is a query parameter, which the Core
@@ -183,7 +303,7 @@ the runner. The error burst ("Attack detection" in `SPEC.md`) bans it after more
 than 30 such refusals from its address in a minute, as when many jobs upload at
 once. `actions/upload-artifact@v4` does not send the header.
 
-## What body inspection refuses
+### What body inspection refuses
 
 With `SWWAF_WAF_BODY_LIMIT` set, the Core Rule Set reads request bodies too. In
 front of gitea it then refuses these, until their rule ids, named in the request
@@ -195,7 +315,7 @@ log, are added to `SWWAF_WAF_DISABLED_RULES`:
 - PyPI uploads (922130);
 - attachments named like `debug.log` or `config.yml` (932180).
 
-## What `script/gitea-requests` sends
+### What `script/gitea-requests` sends
 
 Of the requests above, the script sends:
 

docs/image.md

@@ -8,8 +8,7 @@ is pinned that way.
 ## Contents
 
 - Ubuntu 26.04 LTS, pinned by digest.
-- `ca-certificates`, `nix-bin` and `runit` from Ubuntu, from the snapshot of its
-  archive at `20261001T000000Z`.
+- `ca-certificates`, `nix-bin` and `runit` from Ubuntu's archive.
 - Nix, with nixpkgs `nixos-26.05.11045.774debe7a0d1` set up for root as
   `nixpkgs`. No Nix daemon; `build-users-group =` in `/etc/nix/nix.conf`. Root's
   Nix profile, `/nix/var/nix/profiles/default/bin`, last on the `PATH`.
@@ -26,10 +25,8 @@ is pinned that way.
 
 ## Pins
 
-- Ubuntu's packages: the snapshot service, `--snapshot 20261001T000000Z` on both
-  `apt-get update` and `apt-get install`. The SHA-256 hash of each of the
-  snapshot's `InRelease` files is named in the `Dockerfile` and checked after
-  `apt-get update`. The hashes are the amd64 archive's.
+- Ubuntu's packages are not pinned: they come from the live archive, whose
+  packages change with every update.
 - nixpkgs: the release file `nixexprs.tar.xz` of
   `nixos-26.05.11045.774debe7a0d1` on `releases.nixos.org`, named with its
   SHA-256 hash.

docs/request-log.md

@@ -107,6 +107,35 @@ Every one of these lines has:
 - `would_action`: in `observe` mode, what `enforce` mode would have done with a
   request it would have refused. `action` then names what was done, normally
   `forward`.
+- `heuristic`: the heuristic that refused the request, in `observe` mode too. It
+  is left out when none did.
+- `heuristic_figures`: an object of the figures that heuristic acted on. Each
+  heuristic and its figures:
+    - `deny_nets`: `netblock`, the entry of `SWWAF_DENY_NETS` the client is in;
+    - `active_ban`: `netblock`, the ban's netblock, and `ban_expires`;
+    - `countries`: `country`, and `setting`, the country list that refused it;
+    - `blocklists`: `lists`, the blocklist URLs that list the client;
+    - `crowdsec`: `scenario`, the decision's scenario, and `expires`, when the
+      decision ends;
+    - `dnsbl`: `zones`, the DNS blocklist zones that list the client, their keys
+      masked;
+    - `abuseipdb`: `score`, and `min_score`, `SWWAF_ABUSEIPDB_MIN_SCORE`;
+    - `rate_limits`: `window`, `count` and `limit`;
+    - `trap_paths`: `path`, the trap path asked for;
+    - `rule_files`: `rule_id` and `rule_action`, of the rule that refused it;
+    - `header_limits`: `fields`, `fields_limit`, `cookies` and `cookies_limit`;
+    - `core_rule_set`: `score`, and `threshold`, `SWWAF_WAF_ANOMALY_THRESHOLD`;
+    - `refusal_limit`: `window`, `count` and `limit`, of the error burst;
+    - `byte_limits`: `window`, `count` and `limit`, the count in bytes.
+- `after_answer_heuristic`: the heuristic that banned the client after
+  `servewaf` answered the request, in `observe` mode too: `refusal_limit` or
+  `byte_limits`.
+- `after_answer_heuristic_figures`: an object of the figures that heuristic
+  acted on, as listed above.
+
+    `byte_limits` bans when the report comes, so only the `report` line names
+    it.
+
 - `limit_percent` and `limit_percent_setting`: the client's percentage of the
   rate limits and the setting that lowered it, when one did. `bytes_percent` and
   `bytes_percent_setting` do the same for the byte limits.

docs/settings.md

@@ -99,19 +99,22 @@ chooses between the two (see "The image's command" below).
 
 ## Request rate limits, per client
 
-- `SWWAF_RATE_LIMIT_PER_MINUTE` (default `500`, about 8 a second): the most
-  requests a client may make in a minute. A count or `off`. The default catches,
-  within seconds, a client firing requests as fast as it can. It leaves room for
-  a fleet of about 20 agents at its busiest, about 120 requests a minute. It
-  also leaves room for a few quick first visits to gitea with an empty cache,
-  about 40 files each.
-- `SWWAF_RATE_LIMIT_PER_HOUR` (default `20000`, about 5.5 a second): the most
-  requests a client may make in an hour. A count or `off`. The default leaves
-  room for an automation fleet at work. It catches a client that keeps up more
-  than about 5.5 a second for an hour.
-- `SWWAF_RATE_LIMIT_PER_DAY` (default `300000`, about 3.5 a second): the most
-  requests a client may make in a day. A count or `off`. The default catches a
-  scraper that keeps up 4 a second around the clock.
+- `SWWAF_RATE_LIMIT_PER_MINUTE` (default `120`, 2 a second): the most requests a
+  client may make in a minute. A count or `off`. The default leaves room for a
+  person opening two gitea pages at once with an empty cache, up to 60 files
+  each.
+- `SWWAF_RATE_LIMIT_PER_HOUR` (default `1500`): the most requests a client may
+  make in an hour. A count or `off`. It is the main limit against scrapers. A
+  person reading code in gitea for an hour, a page every 20 seconds, makes
+  about 900. A scraper making one request every 2 seconds makes 1,800 an hour,
+  more than the limit.
+- `SWWAF_RATE_LIMIT_PER_DAY` (default `6000`): the most requests a client may
+  make in a day. A count or `off`. The default is four hours at the hour limit.
+  A scraper making one request every 10 seconds makes 8,640 a day, more than the
+  limit.
+- An Actions runner asks gitea for work all day and can pass the limits. Put the
+  runners' addresses in `SWWAF_RATE_LIMIT_EXEMPT_NETS`. Do the same for a
+  network where many people share one address, such as an office.
 - Counting cannot catch a client that stays under all three limits (see "Request
   rate limits, per client" in [`SPEC.md`](../SPEC.md)).
 - `SWWAF_RATE_LIMIT_EXEMPT_PATHS` (default empty): path prefixes exempt from
@@ -119,8 +122,8 @@ chooses between the two (see "The image's command" below).
 
 ## Byte limits, per client
 
-- `SWWAF_BYTES_LIMIT_PER_MINUTE` (default `4G`), `SWWAF_BYTES_LIMIT_PER_HOUR`
-  (default `20G`) and `SWWAF_BYTES_LIMIT_PER_DAY` (default `200G`): the most
+- `SWWAF_BYTES_LIMIT_PER_MINUTE` (default `off`), `SWWAF_BYTES_LIMIT_PER_HOUR`
+  (default `50G`) and `SWWAF_BYTES_LIMIT_PER_DAY` (default `100G`): the most
   bytes counted for a client in each window. A size or `off`.
 - `SWWAF_BYTES_COUNT` (default `both`): which body bytes the byte limits count:
   `response`, `request` or `both`.

internal/config/config.go

@@ -3,7 +3,8 @@
 // servewaf` start with SWWAF_, every one of them has a default, and most can be
 // given as a file instead. Those of `smallwebwaf rproxy` start with SWRP_. Each
 // of them but SWRP_WAF_BACKEND has a default, and none can be given as a file,
-// since rproxy never touches disk.
+// since rproxy never touches disk. SMALLWEBWAF_COMMAND chooses which of the two
+// the image runs.
 package config
 
 import (
@@ -370,6 +371,7 @@ var (
 	errDBPathUnused    = errors.New("only file reads it")
 	errOver64K         = errors.New(
 		"is more than 64K, the most servewaf gets of a body")
+	errNotCommand           = errors.New("is not rproxy or servewaf")
 	errNotDurationAboveZero = errors.New(
 		"is not a duration above zero, such as 1h or 7d")
 	errNotNumberAboveZero = errors.New(
@@ -466,13 +468,13 @@ func FromEnvironment(lookupEnv func(string) (string, bool)) (*Config, error) {
 		AllowNets:            env.netblocks("SWWAF_ALLOW_NETS", ""),
 		RateLimitExemptNets:  env.netblocks("SWWAF_RATE_LIMIT_EXEMPT_NETS", ""),
 		DenyNets:             env.netblocks("SWWAF_DENY_NETS", ""),
-		RateLimitPerMinute:   env.count("SWWAF_RATE_LIMIT_PER_MINUTE", "500"),
-		RateLimitPerHour:     env.count("SWWAF_RATE_LIMIT_PER_HOUR", "20000"),
-		RateLimitPerDay:      env.count("SWWAF_RATE_LIMIT_PER_DAY", "300000"),
+		RateLimitPerMinute:   env.count("SWWAF_RATE_LIMIT_PER_MINUTE", "120"),
+		RateLimitPerHour:     env.count("SWWAF_RATE_LIMIT_PER_HOUR", "1500"),
+		RateLimitPerDay:      env.count("SWWAF_RATE_LIMIT_PER_DAY", "6000"),
 		RateLimitExemptPaths: env.pathPrefixes("SWWAF_RATE_LIMIT_EXEMPT_PATHS", ""),
-		BytesLimitPerMinute:  env.size("SWWAF_BYTES_LIMIT_PER_MINUTE", "4G"),
-		BytesLimitPerHour:    env.size("SWWAF_BYTES_LIMIT_PER_HOUR", "20G"),
-		BytesLimitPerDay:     env.size("SWWAF_BYTES_LIMIT_PER_DAY", "200G"),
+		BytesLimitPerMinute:  env.size("SWWAF_BYTES_LIMIT_PER_MINUTE", "off"),
+		BytesLimitPerHour:    env.size("SWWAF_BYTES_LIMIT_PER_HOUR", "50G"),
+		BytesLimitPerDay:     env.size("SWWAF_BYTES_LIMIT_PER_DAY", "100G"),
 		BytesCount:           env.bytesCount("SWWAF_BYTES_COUNT", "both"),
 		LookupSource:         env.lookupSource("SWWAF_LOOKUP_SOURCE", "geojs"),
 		LookupDBPath:         env.value("SWWAF_LOOKUP_DB_PATH", ""),
@@ -570,6 +572,22 @@ func FromEnvironment(lookupEnv func(string) (string, bool)) (*Config, error) {
 	return cfg, nil
 }
 
+// Command reads only SMALLWEBWAF_COMMAND, the command the image runs and its
+// health check checks: rproxy when it is unset or empty, or servewaf. It cannot
+// be given as a file. Any other value is an error that names the setting.
+func Command(lookupEnv func(string) (string, bool)) (string, error) {
+	command, _ := lookupEnv("SMALLWEBWAF_COMMAND")
+
+	switch command {
+	case "", "rproxy":
+		return "rproxy", nil
+	case "servewaf":
+		return command, nil
+	default:
+		return "", fmt.Errorf("SMALLWEBWAF_COMMAND: %q %w", command, errNotCommand)
+	}
+}
+
 // ServeWAFListenAddr reads only SWWAF_LISTEN_ADDR, which may be given as a
 // file, as FromEnvironment does. The health check in servewaf's container needs
 // no other setting, so it reads no other, nor a file that another names.

internal/config/config_test.go

@@ -244,9 +244,9 @@ func TestDefaults(t *testing.T) {
 	wantSettings(t, cfg, config.Config{
 		ListenAddr:           ":8080",
 		Observe:              false,
-		RateLimitPerMinute:   500,
-		RateLimitPerHour:     20000,
-		RateLimitPerDay:      300000,
+		RateLimitPerMinute:   120,
+		RateLimitPerHour:     1500,
+		RateLimitPerDay:      6000,
 		BanResponse:          403,
 		LimitBanDuration:     time.Hour,
 		LimitBanRepeatWindow: 24 * time.Hour,
@@ -266,8 +266,8 @@ func TestDefaults(t *testing.T) {
 		LookupSource: defaultLookupSource, LookupTimeout: 800 * time.Millisecond,
 	})
 	wantByteLimitSettings(t, cfg, config.Config{
-		BytesLimitPerMinute: 4 << 30, BytesLimitPerHour: 20 << 30,
-		BytesLimitPerDay: 200 << 30, BytesCount: "both",
+		BytesLimitPerMinute: 0, BytesLimitPerHour: 50 << 30,
+		BytesLimitPerDay: 100 << 30, BytesCount: "both",
 	})
 
 	wantNetblocks(t, cfg.AllowNets)
@@ -308,7 +308,7 @@ func TestNoSingleRequestBreaksAByteLimitAtTheDefaults(t *testing.T) {
 	for _, limit := range []int64{
 		cfg.BytesLimitPerMinute, cfg.BytesLimitPerHour, cfg.BytesLimitPerDay,
 	} {
-		if largest > limit {
+		if limit != 0 && largest > limit { // 0 is off
 			t.Errorf("a request of %d bytes breaks the byte limit of %d", largest, limit)
 		}
 	}
@@ -2271,12 +2271,12 @@ func TestLogsEachSettingWithItsValue(t *testing.T) {
 		rateLimitExemptNets:  "",
 		denyNets:             "",
 		rateLimitPerMinute:   "45",
-		rateLimitPerHour:     "20000",
-		rateLimitPerDay:      "300000",
+		rateLimitPerHour:     "1500",
+		rateLimitPerDay:      "6000",
 		rateLimitExemptPaths: "",
-		bytesLimitPerMinute:  "4G",
-		bytesLimitPerHour:    "20G",
-		bytesLimitPerDay:     "200G",
+		bytesLimitPerMinute:  "off",
+		bytesLimitPerHour:    "50G",
+		bytesLimitPerDay:     "100G",
 		bytesCount:           "both",
 		lookupSource:         defaultLookupSource,
 		lookupDBPath:         "",

internal/proxy/countries.go

@@ -1,21 +0,0 @@
-package proxy
-
-import (
-	"slices"
-)
-
-// countryDenied reports whether the country lists refuse the request, by
-// the client's country as it was looked up. A client without a country,
-// or whose country cannot be found, is refused only by
-// SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES.
-func (rq *request) countryDenied() bool {
-	denied := rq.h.config.DeniedCountries
-	allowed := rq.h.config.ExclusivelyAllowedCountries
-	country := rq.line.Country
-
-	if slices.Contains(denied, country) {
-		return true
-	}
-
-	return len(allowed) > 0 && !slices.Contains(allowed, country)
-}

internal/proxy/reputation.go

@@ -1,122 +0,0 @@
-package proxy
-
-import (
-	"context"
-	"time"
-
-	"sneak.berlin/go/smallwebwaf/internal/alerts"
-	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
-	"sneak.berlin/go/smallwebwaf/internal/reputation"
-)
-
-// deny is the SWWAF_BLOCKLIST_ACTION and the SWWAF_REPUTATION_ACTION that
-// refuses the requests of a client a source lists.
-const deny = "deny"
-
-// blocklistDenied notes the blocklists that list the client, as
-// noteListed does, and reports whether SWWAF_BLOCKLIST_ACTION, being deny,
-// refuses the request. Being limit, it lowers the client's limits instead
-// (see limitPercentages), and being log, it does nothing more.
-func (rq *request) blocklistDenied() bool {
-	listedBy := rq.h.lists.ListedBy(rq.client)
-	rq.blocklisted = len(listedBy) > 0
-	rq.noteListed(listedBy, "listed by a blocklist")
-
-	return rq.blocklisted && rq.h.config.BlocklistAction == deny
-}
-
-// crowdSecBanned reports whether a decision of the CrowdSec decision list
-// on the client is in force at now. If one is, it notes the list, as
-// noteHit does, and bans the client until that decision ends.
-func (rq *request) crowdSecBanned(now time.Time) bool {
-	decision, listed := rq.h.lists.CrowdSecDecision(rq.client, now)
-	if !listed {
-		return false
-	}
-
-	rq.noteHit(bans.ReputationHit{Source: rq.h.config.CrowdSecDecisionsURL},
-		"listed by the CrowdSec decision list")
-	rq.banForCrowdSec(now, decision)
-
-	return true
-}
-
-// dnsblDenied notes the DNSBL zones whose verdict lists the client, as
-// noteListed does, and reports whether SWWAF_REPUTATION_ACTION, being
-// deny, refuses the request. Being limit, it lowers the client's limits
-// instead (see limitPercentages), and being log, it does nothing more. A
-// zone without a verdict on the client is asked about it in the
-// background, and the request does not wait for the answer. ctx is the
-// request's own context.
-func (rq *request) dnsblDenied(ctx context.Context) bool {
-	listedBy := rq.h.dnsbl.ListedBy(ctx, rq.client)
-	rq.dnsblListed = len(listedBy) > 0
-	rq.noteListed(listedBy, "listed by a DNSBL zone")
-
-	return rq.dnsblListed && rq.h.config.ReputationAction == deny
-}
-
-// abuseIPDBDenied notes AbuseIPDB, as noteHit does, with the score, when
-// its score of the client is a hit, and reports whether
-// SWWAF_REPUTATION_ACTION, being deny, refuses the request, as dnsblDenied
-// does for a zone. While SWWAF_ABUSEIPDB_KEY is unset it does nothing. A
-// client without a score is checked in the background, by the request's
-// address, if its history counts an offence, and the request does not
-// wait for the answer. The score is then used for each address of the
-// client. ctx is the request's own context.
-func (rq *request) abuseIPDBDenied(ctx context.Context) bool {
-	if rq.h.config.AbuseIPDBKey == "" {
-		return false
-	}
-
-	client := rq.h.clientGroup(rq.client)
-	held, _ := rq.h.limiter.Client(client)
-	offender := held.History.Offences != ratelimit.Offences{}
-
-	score, hit := rq.h.abuseIPDB.Hit(ctx, client, rq.client, offender)
-	if !hit {
-		return false
-	}
-
-	rq.abuseIPDBHit = true
-	rq.noteHit(bans.ReputationHit{Source: reputation.AbuseIPDBSource, Score: &score},
-		"scored by AbuseIPDB at or over SWWAF_ABUSEIPDB_MIN_SCORE")
-
-	return rq.h.config.ReputationAction == deny
-}
-
-// noteListed notes each of sources, the URLs of the blocklists or the
-// DNSBL zones, their keys masked, that list the client, as noteHit does,
-// with reason.
-func (rq *request) noteListed(sources []string, reason string) {
-	for _, source := range sources {
-		rq.noteHit(bans.ReputationHit{Source: source}, reason)
-	}
-}
-
-// noteHit adds hit's source, which lists the client, to the log line's
-// reputation, and hit to the notes of a ban the request makes, counts the
-// source in the metrics, and raises a reputation_hit alert with reason,
-// whose detail gives hit's source and score.
-func (rq *request) noteHit(hit bans.ReputationHit, reason string) {
-	detail := map[string]any{"source": hit.Source}
-	if hit.Score != nil {
-		detail["score"] = *hit.Score
-	}
-
-	rq.line.Reputation = append(rq.line.Reputation, hit.Source)
-	rq.reputation = append(rq.reputation, hit)
-	rq.h.metrics.ReputationHit(hit.Source)
-	rq.h.alerts.Raise(alerts.Alert{
-		Event:    alerts.EventReputationHit,
-		Host:     rq.site,
-		Client:   rq.client,
-		Netblock: rq.h.clientGroup(rq.client),
-		ASN:      rq.line.ASN,
-		ASName:   rq.line.ASName,
-		Country:  rq.line.Country,
-		Reason:   reason,
-		Detail:   detail,
-	})
-}

internal/proxy/rules.go

@@ -1,64 +0,0 @@
-package proxy
-
-import (
-	"slices"
-	"time"
-
-	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/requestlog"
-	"sneak.berlin/go/smallwebwaf/internal/rules"
-)
-
-// trapPath reports whether the request asks for a path in
-// SWWAF_TRAP_PATHS: its path as a path rule sees it, without the query,
-// as sent or once percent-decoded, is one of them. Such a request is a
-// clear sign of attack, as a ban rule's match is: it bans the client's
-// netblock, or in observe mode raises the alert for the ban it would have
-// made. The ban's notes give the path as sent.
-func (rq *request) trapPath(now time.Time) bool {
-	path := rules.Path(rq.in)
-	if !slices.Contains(rq.h.config.TrapPaths, path) &&
-		!slices.Contains(rq.h.config.TrapPaths, rules.DecodeOnce(path)) {
-		return false
-	}
-
-	rq.attack = true
-	rq.banForAttack(now, bans.Notes{TrapPath: path})
-
-	return true
-}
-
-// checkRules checks the request against the rules of the rule files at
-// now, notes the ids of those it matches in the log line, and returns the
-// action of the rule that refuses it, ActionRuleBlocked for a block rule
-// and ActionBanned for a ban rule, or "" when none does. A ban rule bans
-// the client's netblock for a clear sign of attack, or in observe mode
-// raises the alert for the ban it would have made. Either rule's match
-// is noted as an offence, for the client's history.
-func (rq *request) checkRules(now time.Time) string {
-	matched := rq.h.rules.Match(rq.in)
-
-	for _, rule := range matched {
-		rq.line.RuleIDs = append(rq.line.RuleIDs, rule.ID)
-		rq.h.metrics.RuleMatched(rule.ID, rule.Action)
-	}
-
-	if len(matched) == 0 {
-		return ""
-	}
-
-	// Only the last rule matched can refuse the request.
-	switch last := matched[len(matched)-1]; last.Action {
-	case rules.ActionBlock:
-		rq.ruleBlocked = true
-
-		return requestlog.ActionRuleBlocked
-	case rules.ActionBan:
-		rq.attack = true
-		rq.banForAttack(now, bans.Notes{RuleID: last.ID, Target: last.Target})
-
-		return requestlog.ActionBanned
-	default:
-		return ""
-	}
-}

internal/requestlog/requestlog.go

@@ -131,6 +131,16 @@ type Line struct {
 	// ActionRuleBlocked, ActionWAFBlocked, or, in servewaf, ActionTooLarge
 	// for the header limits.
 	WouldAction string `json:"would_action,omitempty"`
+	// Heuristic is the name of the heuristic that refused the request, in
+	// observe mode too, and HeuristicFigures are the figures it acted on, by
+	// name.
+	Heuristic        string         `json:"heuristic,omitempty"`
+	HeuristicFigures map[string]any `json:"heuristic_figures,omitempty"`
+	// AfterAnswerHeuristic and AfterAnswerHeuristicFigures are the same for
+	// the heuristic that banned the client after servewaf answered the
+	// request.
+	AfterAnswerHeuristic        string         `json:"after_answer_heuristic,omitempty"`
+	AfterAnswerHeuristicFigures map[string]any `json:"after_answer_heuristic_figures,omitempty"` //nolint:lll // a struct tag cannot be split
 	// LimitPercent and LimitPercentSetting are, for a request the rate
 	// limits counted whose client a biased threshold gives a percentage of
 	// the rate limits below 100, that percentage and the setting that gave

internal/rproxy/limits_test.go

@@ -1,7 +1,9 @@
 package rproxy_test
 
 import (
+	"bufio"
 	"bytes"
+	"errors"
 	"io"
 	"log/slog"
 	"net"
@@ -14,9 +16,9 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/config"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rproxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // post is the start of a POST whose headers end with what follows it.
@@ -69,11 +71,11 @@ func TestABodyAnnouncedOverItsLimitIsRefusedOnceServeWAFAllowsIt(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, func(http.ResponseWriter, *http.Request) {
 				t.Error("the app was asked")
 			})
-			addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+			addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 				maxRequestSize: tc.limit,
 			})
 
@@ -83,11 +85,11 @@ func TestABodyAnnouncedOverItsLimitIsRefusedOnceServeWAFAllowsIt(t *testing.T) {
 				t.Errorf("answered %+v, want 413", got)
 			}
 
-			if asked := servewaf.question(t); len(asked.body) != tc.asked {
+			if asked := standIn.question(t); len(asked.body) != tc.asked {
 				t.Errorf("the question carries %d bytes, want %d", len(asked.body), tc.asked)
 			}
 
-			report := servewaf.report(t)
+			report := standIn.report(t)
 			if report.Status != http.StatusRequestEntityTooLarge {
 				t.Errorf("report %+v, want status 413", report)
 			}
@@ -98,9 +100,9 @@ func TestABodyAnnouncedOverItsLimitIsRefusedOnceServeWAFAllowsIt(t *testing.T) {
 func TestADenyOutranksTheBodySizeLimit(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, deny)
+	standIn := startServeWAF(t, deny)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		maxRequestSize: "1K",
 	})
 
@@ -130,12 +132,12 @@ func TestABodyNotAnnouncedOverItsLimitIsRefused(t *testing.T) {
 
 			var asked atomic.Bool
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
 				asked.Store(true)
 				greet(w, r)
 			})
-			addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+			addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 				maxRequestSize: tc.limit,
 			})
 
@@ -163,12 +165,12 @@ func TestAResponseOverItsLimit(t *testing.T) {
 	t.Run("announced, is refused", func(t *testing.T) {
 		t.Parallel()
 
-		servewaf := startServeWAF(t, allow)
+		standIn := startServeWAF(t, allow)
 		app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 			w.Header().Set(contentLengthHeader, strconv.Itoa(len(large)))
 			_, _ = io.WriteString(w, large)
 		})
-		addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+		addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 			maxResponseSize: "1K",
 		})
 
@@ -177,7 +179,7 @@ func TestAResponseOverItsLimit(t *testing.T) {
 			t.Errorf("answered %d, want 502", got.status)
 		}
 
-		if report := servewaf.report(t); report.Status != http.StatusBadGateway {
+		if report := standIn.report(t); report.Status != http.StatusBadGateway {
 			t.Errorf("report %+v, want status 502", report)
 		}
 	})
@@ -185,13 +187,13 @@ func TestAResponseOverItsLimit(t *testing.T) {
 	t.Run("not announced, is cut off", func(t *testing.T) {
 		t.Parallel()
 
-		servewaf := startServeWAF(t, allow)
+		standIn := startServeWAF(t, allow)
 		app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 			_, _ = io.WriteString(w, large[:1])
 			_ = http.NewResponseController(w).Flush()
 			_, _ = io.WriteString(w, large[1:])
 		})
-		addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+		addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 			maxResponseSize: "1K",
 		})
 
@@ -203,7 +205,7 @@ func TestAResponseOverItsLimit(t *testing.T) {
 			t.Errorf("read %d bytes (%v), want the answer cut off", len(text), err)
 		}
 
-		report := servewaf.report(t)
+		report := standIn.report(t)
 		if report.Status != http.StatusOK || report.ResponseBytes > 1<<10 {
 			t.Errorf("report %+v, want status 200 and at most 1K of the answer", report)
 		}
@@ -215,11 +217,11 @@ func TestAHeadWhoseAnswerAnnouncesMoreThanTheResponseLimitIsPassedOn(t *testing.
 
 	const announced = "2048"
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 		w.Header().Set(contentLengthHeader, announced)
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		maxResponseSize: "1K",
 	})
 
@@ -238,9 +240,9 @@ func TestASettingOfOffSetsNoLimit(t *testing.T) {
 		t.Run(setting, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, greet)
-			addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+			addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 				setting: "off",
 			})
 
@@ -249,7 +251,7 @@ func TestASettingOfOffSetsNoLimit(t *testing.T) {
 			wantGreeting(t, visit(t, newRequest(t, http.MethodPost, addr, "/",
 				strings.NewReader("a body"))))
 
-			if got := get(t, addr, proxy.HealthPath); got.status != http.StatusOK {
+			if got := get(t, addr, servewaf.HealthPath); got.status != http.StatusOK {
 				t.Errorf("answered %+v, want rproxy's own 200", got)
 			}
 		})
@@ -268,9 +270,9 @@ func TestAVisitorTooSlowToSendTheFirstPartIsAnswered408(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, greet)
-			addr, out := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+			addr, out := startRProxy(t, standIn.URL, app.URL, map[string]string{
 				maxRequestTime: "500",
 			})
 
@@ -286,11 +288,11 @@ func TestAVisitorTooSlowToSendTheFirstPartIsAnswered408(t *testing.T) {
 				t.Errorf("line %v, want no disposition and 10 bytes", line)
 			}
 
-			if len(servewaf.questions) != 0 {
+			if len(standIn.questions) != 0 {
 				t.Error("servewaf was asked")
 			}
 
-			servewaf.wantNoReport(t)
+			standIn.wantNoReport(t)
 		})
 	}
 }
@@ -298,9 +300,9 @@ func TestAVisitorTooSlowToSendTheFirstPartIsAnswered408(t *testing.T) {
 func TestAVisitorThatGoesAwayBeforeTheFirstPartIsNotAsked(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 	conn := dial(t, addr)
 	send(t, conn, post+announcedLength(100)+"some of it")
@@ -311,7 +313,7 @@ func TestAVisitorThatGoesAwayBeforeTheFirstPartIsNotAsked(t *testing.T) {
 		t.Errorf("line %v, want no answer and no disposition", line)
 	}
 
-	if len(servewaf.questions) != 0 {
+	if len(standIn.questions) != 0 {
 		t.Error("servewaf was asked")
 	}
 }
@@ -332,9 +334,9 @@ func TestABodyThatCannotBeReadClosesTheConnectionWithoutAnAnswer(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, greet)
-			addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+			addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 			conn := dial(t, addr)
 			send(t, conn, tc.request)
@@ -362,7 +364,7 @@ func TestABodyThatCannotBeReadClosesTheConnectionWithoutAnAnswer(t *testing.T) {
 				t.Errorf("line %v, want no answer and no disposition", line)
 			}
 
-			if len(servewaf.questions) != 0 {
+			if len(standIn.questions) != 0 {
 				t.Error("servewaf was asked")
 			}
 		})
@@ -402,11 +404,11 @@ func TestABodyLeftUnreadIsReadOnlyUntilTheRequestTimeLimit(t *testing.T) {
 		announced = 100 * questionBodyMaxBytes
 	)
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 		w.WriteHeader(http.StatusNoContent)
 	})
-	_, _, server := startServer(t, servewaf.URL, app.URL, map[string]string{
+	_, _, server := startServer(t, standIn.URL, app.URL, map[string]string{
 		maxRequestTime: strconv.FormatInt(limit.Milliseconds(), 10),
 	})
 
@@ -452,9 +454,9 @@ func TestAnAnswerRProxyGivesItselfHasTheResponseTimeToBeSent(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, deny)
+			standIn := startServeWAF(t, deny)
 			app := startApp(t, greet)
-			_, _, server := startServer(t, servewaf.URL, app.URL, map[string]string{
+			_, _, server := startServer(t, standIn.URL, app.URL, map[string]string{
 				maxResponseTime: strconv.FormatInt(limit.Milliseconds(), 10),
 			})
 
@@ -482,9 +484,9 @@ func TestAnAnswerRProxyGivesItselfHasTheResponseTimeToBeSent(t *testing.T) {
 func TestAVisitorTooSlowToSendTheRestIsAnswered408(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		maxRequestTime: "3000",
 	})
 
@@ -496,11 +498,11 @@ func TestAVisitorTooSlowToSendTheRestIsAnswered408(t *testing.T) {
 		t.Errorf("status %d, want 408", status)
 	}
 
-	if asked := servewaf.question(t); len(asked.body) != questionBodyMaxBytes {
+	if asked := standIn.question(t); len(asked.body) != questionBodyMaxBytes {
 		t.Errorf("the question carries %d bytes", len(asked.body))
 	}
 
-	if report := servewaf.report(t); report.Status != http.StatusRequestTimeout {
+	if report := standIn.report(t); report.Status != http.StatusRequestTimeout {
 		t.Errorf("report %+v, want status 408", report)
 	}
 }
@@ -551,8 +553,8 @@ func TestAnAppTooSlowToTakeTheRequestIsAnswered504(t *testing.T) {
 		writeSize = 32 << 10
 	)
 
-	servewaf := startServeWAF(t, allow)
-	addr, _ := startRProxy(t, servewaf.URL, startAppThatTakesNothing(t),
+	standIn := startServeWAF(t, allow)
+	addr, _ := startRProxy(t, standIn.URL, startAppThatTakesNothing(t),
 		map[string]string{maxRequestTime: "3000"})
 
 	conn := dial(t, addr)
@@ -578,14 +580,14 @@ func TestAnAppTooSlowToAnswerIsAnswered504(t *testing.T) {
 	t.Parallel()
 
 	release := make(chan struct{})
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(http.ResponseWriter, *http.Request) {
 		<-release
 	})
 
 	t.Cleanup(func() { close(release) })
 
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		maxResponseTime: "300",
 	})
 
@@ -594,7 +596,7 @@ func TestAnAppTooSlowToAnswerIsAnswered504(t *testing.T) {
 		t.Errorf("answered %d, want 504", got.status)
 	}
 
-	if report := servewaf.report(t); report.Status != http.StatusGatewayTimeout {
+	if report := standIn.report(t); report.Status != http.StatusGatewayTimeout {
 		t.Errorf("report %+v, want status 504", report)
 	}
 }
@@ -602,10 +604,12 @@ func TestAnAppTooSlowToAnswerIsAnswered504(t *testing.T) {
 func TestAnAppTooSlowToFinishItsAnswerIsCutOff(t *testing.T) {
 	t.Parallel()
 
+	const start = "the start"
+
 	release := make(chan struct{})
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
-		_, _ = io.WriteString(w, "the start")
+		_, _ = io.WriteString(w, start)
 		_ = http.NewResponseController(w).Flush()
 
 		<-release
@@ -613,20 +617,32 @@ func TestAnAppTooSlowToFinishItsAnswerIsCutOff(t *testing.T) {
 
 	t.Cleanup(func() { close(release) })
 
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
-		maxResponseTime: "300",
+	// The time limit is long enough for a loaded host to pass on the start of the
+	// answer before it runs out.
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
+		maxResponseTime: "3000",
 	})
 
 	conn := dial(t, addr)
 	send(t, conn, "GET / HTTP/1.1\r\nHost: site.example\r\n\r\n")
 
-	// dial's deadline ends this read with an error if the connection stays open.
-	_, err := io.ReadAll(conn)
+	res, err := http.ReadResponse(bufio.NewReader(conn), nil)
 	if err != nil {
-		t.Errorf("read: %v, want the connection closed", err)
+		t.Fatalf("read the answer: %v", err)
 	}
 
-	if report := servewaf.report(t); report.Status != http.StatusOK {
+	// The body breaks off when rproxy closes the connection. If the connection
+	// stays open, dial's deadline ends this read with a timeout instead.
+	body, err := io.ReadAll(res.Body)
+	_ = res.Body.Close()
+
+	if res.StatusCode != http.StatusOK || string(body) != start ||
+		!errors.Is(err, io.ErrUnexpectedEOF) {
+		t.Errorf("answered %d %q (%v), want the app's 200 %q, then the connection closed",
+			res.StatusCode, body, err, start)
+	}
+
+	if report := standIn.report(t); report.Status != http.StatusOK {
 		t.Errorf("report %+v, want the status the visitor got", report)
 	}
 }
@@ -640,7 +656,7 @@ func TestAVisitorTooSlowToTakeTheAnswerIsCutOff(t *testing.T) {
 		writeSize = 32 << 10
 	)
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 		part := make([]byte, writeSize)
 
@@ -651,8 +667,10 @@ func TestAVisitorTooSlowToTakeTheAnswerIsCutOff(t *testing.T) {
 			}
 		}
 	})
-	addr, out := startRProxy(t, servewaf.URL, app.URL, map[string]string{
-		maxResponseTime: "500",
+	// The time limit is long enough for a loaded host to start passing on the
+	// answer before it runs out.
+	addr, out := startRProxy(t, standIn.URL, app.URL, map[string]string{
+		maxResponseTime: "3000",
 	})
 
 	// The visitor asks, and never reads the answer.
@@ -666,7 +684,7 @@ func TestAVisitorTooSlowToTakeTheAnswerIsCutOff(t *testing.T) {
 		t.Errorf("line %v, want status 200 and the answer cut off", line)
 	}
 
-	report := servewaf.report(t)
+	report := standIn.report(t)
 	if report.Status != http.StatusOK || report.ResponseBytes >= bodySize {
 		t.Errorf("report %+v, want status 200 and the answer cut off", report)
 	}
@@ -675,15 +693,15 @@ func TestAVisitorTooSlowToTakeTheAnswerIsCutOff(t *testing.T) {
 func TestAnAppThatCannotBeReachedIsAnswered502WithAReport(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
-	addr, _ := startRProxy(t, servewaf.URL, nowhere, nil)
+	standIn := startServeWAF(t, allow)
+	addr, _ := startRProxy(t, standIn.URL, nowhere, nil)
 
 	got := get(t, addr, "/")
 	if got.status != http.StatusBadGateway {
 		t.Errorf("answered %d, want 502", got.status)
 	}
 
-	if report := servewaf.report(t); report.Status != http.StatusBadGateway {
+	if report := standIn.report(t); report.Status != http.StatusBadGateway {
 		t.Errorf("report %+v, want status 502", report)
 	}
 }
@@ -691,11 +709,11 @@ func TestAnAppThatCannotBeReachedIsAnswered502WithAReport(t *testing.T) {
 func TestAVisitorThatStopsSendingAfterTheAppHasAnsweredGetsTheAnswer(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 		_, _ = io.WriteString(w, greeting)
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		maxRequestTime: "3000",
 	})
 
@@ -714,12 +732,12 @@ func TestAVisitorThatStopsSendingWhileTheAppWorksGetsNoAnswer(t *testing.T) {
 	t.Parallel()
 
 	working := make(chan struct{})
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(_ http.ResponseWriter, r *http.Request) {
 		close(working)
 		<-r.Context().Done()
 	})
-	addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 	conn := dial(t, addr)
 	send(t, conn, "GET / HTTP/1.1\r\nHost: site.example\r\n\r\n")
@@ -755,7 +773,7 @@ func TestTheRequestTimeLimitDoesNotCutAnAnswerOnceTheAppHasTheRequest(t *testing
 
 	const answer = "the end of a long answer"
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
 		_, _ = io.Copy(io.Discard, r.Body)
 		_ = http.NewResponseController(w).Flush()
@@ -764,7 +782,7 @@ func TestTheRequestTimeLimitDoesNotCutAnAnswerOnceTheAppHasTheRequest(t *testing
 
 		_, _ = io.WriteString(w, answer)
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		maxRequestTime: "2000",
 	})
 
@@ -784,17 +802,19 @@ func TestAVisitorThatStopsSendingGetsAnAnswerRProxyGivesByTheDeadline(t *testing
 		{"a deny", post, http.StatusForbidden},
 		{
 			"the health check",
-			"GET " + proxy.HealthPath + " HTTP/1.1\r\nHost: site.example\r\n",
+			"GET " + servewaf.HealthPath + " HTTP/1.1\r\nHost: site.example\r\n",
 			http.StatusOK,
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, deny)
+			standIn := startServeWAF(t, deny)
 			app := startApp(t, greet)
-			addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
-				maxRequestTime: "500",
+			// The time limit is long enough for a loaded host to read the first part of
+			// the body before it runs out.
+			addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
+				maxRequestTime: "3000",
 			})
 
 			// Go's server waits for a little of the body left before it sends an answer,

internal/rproxy/question_test.go

@@ -12,11 +12,11 @@ import (
 	"strings"
 	"testing"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // questionBodyMaxBytes is the most of a body a question carries.
-const questionBodyMaxBytes = proxy.QuestionBodyMaxBytes
+const questionBodyMaxBytes = servewaf.QuestionBodyMaxBytes
 
 // chunked is the encoding of a body whose length the visitor did not announce.
 const chunked = "chunked"
@@ -29,9 +29,9 @@ const pathGoReencodes = "/some%2Fpath/with%20space|pipe"
 func TestQuestionIsTheVisitorsRequestWithRProxysHeaders(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	const target = pathGoReencodes + "?b=2&a=1&bad=%zz;x"
 
@@ -42,16 +42,16 @@ func TestQuestionIsTheVisitorsRequestWithRProxysHeaders(t *testing.T) {
 	req.Header.Set(forwardedForHeader, "198.51.100.1")
 	req.Header.Set(forwardedProtoHeader, "gopher")
 	req.Header.Set(requestIDHeader, "the-visitor's")
-	req.Header.Set(proxy.ClientHeader, "198.51.100.2")
-	req.Header.Set(proxy.PeerHeader, "198.51.100.3")
-	req.Header.Set(proxy.ContentLengthHeader, "12345")
+	req.Header.Set(servewaf.ClientHeader, "198.51.100.2")
+	req.Header.Set(servewaf.PeerHeader, "198.51.100.3")
+	req.Header.Set(servewaf.ContentLengthHeader, "12345")
 	// Go's client then sends no User-Agent, so that one in the question would be
 	// Go's own.
 	req.Header["User-Agent"] = nil
 
 	wantGreeting(t, visit(t, req))
 
-	asked := servewaf.question(t)
+	asked := standIn.question(t)
 	if asked.method != http.MethodDelete || asked.target != target ||
 		asked.host != site {
 		t.Errorf("asked about %s %s at %s", asked.method, asked.target, asked.host)
@@ -68,8 +68,8 @@ func TestQuestionIsTheVisitorsRequestWithRProxysHeaders(t *testing.T) {
 	want.Set(forwardedForHeader, "198.51.100.1")
 	want.Set(forwardedProtoHeader, "http")
 	want.Set(requestIDHeader, asked.header.Get(requestIDHeader))
-	want.Set(proxy.ClientHeader, localhost)
-	want.Set(proxy.PeerHeader, localhost)
+	want.Set(servewaf.ClientHeader, localhost)
+	want.Set(servewaf.PeerHeader, localhost)
 
 	if !maps.EqualFunc(asked.header, want, slices.Equal) {
 		t.Errorf("the question's headers are %v, want %v", asked.header, want)
@@ -93,14 +93,14 @@ func TestQuestionNamesTheVisitorATrustedProxySpeaksFor(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			forwarded := make(chan http.Header, 1)
 			app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
 				forwarded <- r.Header.Clone()
 
 				greet(w, r)
 			})
-			addr, out := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+			addr, out := startRProxy(t, standIn.URL, app.URL, map[string]string{
 				trustedProxies: tc.trusted,
 			})
 
@@ -109,9 +109,9 @@ func TestQuestionNamesTheVisitorATrustedProxySpeaksFor(t *testing.T) {
 			req.Header.Set(forwardedProtoHeader, "https")
 			wantGreeting(t, visit(t, req))
 
-			asked := servewaf.question(t)
-			if asked.header.Get(proxy.ClientHeader) != tc.client ||
-				asked.header.Get(proxy.PeerHeader) != localhost ||
+			asked := standIn.question(t)
+			if asked.header.Get(servewaf.ClientHeader) != tc.client ||
+				asked.header.Get(servewaf.PeerHeader) != localhost ||
 				asked.header.Get(forwardedForHeader) != visitor ||
 				asked.header.Get(forwardedProtoHeader) != tc.proto {
 				t.Errorf("the question's headers are %v", asked.header)
@@ -157,9 +157,9 @@ func TestQuestionNamesTheClientAsTheForwardedAddressesSay(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, greet)
-			addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+			addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 				trustedProxies: localhost + "/32,10.0.0.0/8",
 			})
 
@@ -167,7 +167,7 @@ func TestQuestionNamesTheClientAsTheForwardedAddressesSay(t *testing.T) {
 			req.Header[forwardedForHeader] = tc.header
 			wantGreeting(t, visit(t, req))
 
-			if got := servewaf.question(t).header.Get(proxy.ClientHeader); got != tc.client {
+			if got := standIn.question(t).header.Get(servewaf.ClientHeader); got != tc.client {
 				t.Errorf("the question names %s, want %s", got, tc.client)
 			}
 		})
@@ -197,7 +197,7 @@ func TestFirst64KiBReachServeWAFAndTheWholeBodyTheApp(t *testing.T) {
 				t.Parallel()
 
 				body := randomBytes(size)
-				servewaf := startServeWAF(t, allow)
+				standIn := startServeWAF(t, allow)
 				received := make(chan []byte, 1)
 				app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
 					whole, _ := io.ReadAll(r.Body)
@@ -205,7 +205,7 @@ func TestFirst64KiBReachServeWAFAndTheWholeBodyTheApp(t *testing.T) {
 
 					greet(w, r)
 				})
-				addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+				addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 				req := newRequest(t, http.MethodPost, addr, "/", bytes.NewReader(body))
 				if !announced {
@@ -215,7 +215,7 @@ func TestFirst64KiBReachServeWAFAndTheWholeBodyTheApp(t *testing.T) {
 
 				wantGreeting(t, visit(t, req))
 
-				asked := servewaf.question(t)
+				asked := standIn.question(t)
 				want := body[:min(size, questionBodyMaxBytes)]
 				wantQuestionBody(t, asked, want, size, announced)
 
@@ -223,7 +223,7 @@ func TestFirst64KiBReachServeWAFAndTheWholeBodyTheApp(t *testing.T) {
 					t.Error("the app did not get the whole body")
 				}
 
-				if report := servewaf.report(t); report.RequestBytes != int64(size) {
+				if report := standIn.report(t); report.RequestBytes != int64(size) {
 					t.Errorf("report %+v, of %d bytes", report, size)
 				}
 			})
@@ -243,7 +243,7 @@ func wantQuestionBody(
 			len(want))
 	}
 
-	values := asked.header.Values(proxy.ContentLengthHeader)
+	values := asked.header.Values(servewaf.ContentLengthHeader)
 
 	if announced {
 		if !slices.Equal(values, []string{strconv.Itoa(size)}) ||
@@ -264,9 +264,9 @@ func wantQuestionBody(
 func TestDenyNeedsOnlyTheFirstPartOfALargeBody(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, deny)
+	standIn := startServeWAF(t, deny)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	// Far more announced than sent. Go's server does not wait for that much, so
 	// the answer comes at once.
@@ -278,7 +278,7 @@ func TestDenyNeedsOnlyTheFirstPartOfALargeBody(t *testing.T) {
 		t.Errorf("status %d, want servewaf's 403", status)
 	}
 
-	if report := servewaf.report(t); report.RequestBytes != questionBodyMaxBytes {
+	if report := standIn.report(t); report.RequestBytes != questionBodyMaxBytes {
 		t.Errorf("report %+v, want the first part's bytes", report)
 	}
 }
@@ -306,8 +306,8 @@ func TestAQuestionCarriesItsBodyWhateverTheMethod(t *testing.T) {
 			t.Run(method+" "+tc.name, func(t *testing.T) {
 				t.Parallel()
 
-				servewaf := startServeWAF(t, deny)
-				addr, _ := startRProxy(t, servewaf.URL, nowhere, nil)
+				standIn := startServeWAF(t, deny)
+				addr, _ := startRProxy(t, standIn.URL, nowhere, nil)
 
 				conn := dial(t, addr)
 				send(t, conn, method+" /x HTTP/1.1\r\nHost: site.example\r\n"+tc.framing)
@@ -316,7 +316,7 @@ func TestAQuestionCarriesItsBodyWhateverTheMethod(t *testing.T) {
 					t.Errorf("status %d, want servewaf's 403", status)
 				}
 
-				asked := servewaf.question(t)
+				asked := standIn.question(t)
 				if string(asked.body) != tc.body ||
 					!slices.Equal(asked.transferEncoding, tc.encoding) {
 					t.Errorf("the question carries %q, encoded %v, want %q, encoded %v",
@@ -334,11 +334,11 @@ func TestAMethodNotPassedOnIsAnswered405(t *testing.T) {
 		t.Run(method, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, func(http.ResponseWriter, *http.Request) {
 				t.Error("the app was asked")
 			})
-			addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+			addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 			got := visit(t, newRequest(t, method, addr, "/", http.NoBody))
 			if got.status != http.StatusMethodNotAllowed ||
@@ -352,11 +352,11 @@ func TestAMethodNotPassedOnIsAnswered405(t *testing.T) {
 				t.Errorf("line %v, want status 405 and no disposition", line)
 			}
 
-			if len(servewaf.questions) != 0 {
+			if len(standIn.questions) != 0 {
 				t.Error("servewaf was asked")
 			}
 
-			servewaf.wantNoReport(t)
+			standIn.wantNoReport(t)
 		})
 	}
 }
@@ -372,18 +372,18 @@ func TestEachMethodPassedOnReachesServeWAFAndTheApp(t *testing.T) {
 			t.Parallel()
 
 			reached := make(chan string, 1)
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, func(_ http.ResponseWriter, r *http.Request) {
 				reached <- r.Method
 			})
-			addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+			addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 			got := visit(t, newRequest(t, method, addr, "/", http.NoBody))
 			if got.status != http.StatusOK {
 				t.Errorf("answered %+v, want the app's 200", got)
 			}
 
-			if asked := servewaf.question(t); asked.method != method {
+			if asked := standIn.question(t); asked.method != method {
 				t.Errorf("servewaf was asked about %s", asked.method)
 			}
 
@@ -416,9 +416,9 @@ func TestARequestThatCannotGoToServeWAFAsSentIsRefused(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, allow)
+			standIn := startServeWAF(t, allow)
 			app := startApp(t, greet)
-			addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+			addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 			conn := dial(t, addr)
 			send(t, conn, request)
@@ -433,11 +433,11 @@ func TestARequestThatCannotGoToServeWAFAsSentIsRefused(t *testing.T) {
 				t.Errorf("line %v, want status 400 and no disposition", line)
 			}
 
-			if len(servewaf.questions) != 0 {
+			if len(standIn.questions) != 0 {
 				t.Error("servewaf was asked")
 			}
 
-			servewaf.wantNoReport(t)
+			standIn.wantNoReport(t)
 		})
 	}
 }
@@ -447,9 +447,9 @@ func TestAHostWithAPercentSignButNoBracketGoesToServeWAF(t *testing.T) {
 
 	const host = "a%b"
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	conn := dial(t, addr)
 	send(t, conn, "GET / HTTP/1.1\r\nHost: "+host+"\r\n\r\n")
@@ -458,7 +458,7 @@ func TestAHostWithAPercentSignButNoBracketGoesToServeWAF(t *testing.T) {
 		t.Errorf("status %d, want the app's 200", status)
 	}
 
-	if asked := servewaf.question(t); asked.host != host {
+	if asked := standIn.question(t); asked.host != host {
 		t.Errorf("asked about the host %q, want %q", asked.host, host)
 	}
 }
@@ -468,15 +468,15 @@ func TestATrustedPeerWithNoForwardedProtoIsAskedAboutAsHTTP(t *testing.T) {
 
 	const want = "http"
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		trustedProxies: localhost + "/32",
 	})
 
 	wantGreeting(t, get(t, addr, "/"))
 
-	asked := servewaf.question(t)
+	asked := standIn.question(t)
 	if got := asked.header.Get(forwardedProtoHeader); got != want {
 		t.Errorf("the question's %s is %q, want %s", forwardedProtoHeader, got, want)
 	}
@@ -497,9 +497,9 @@ func TestAQuestionNamesNoZone(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, deny)
+			standIn := startServeWAF(t, deny)
 			app := startApp(t, greet)
-			_, out, server := startServer(t, servewaf.URL, app.URL, map[string]string{
+			_, out, server := startServer(t, standIn.URL, app.URL, map[string]string{
 				trustedProxies: localhost + "/32",
 			})
 
@@ -509,9 +509,9 @@ func TestAQuestionNamesNoZone(t *testing.T) {
 
 			server.Handler.ServeHTTP(httptest.NewRecorder(), req)
 
-			asked := servewaf.question(t)
-			if asked.header.Get(proxy.ClientHeader) != tc.client ||
-				asked.header.Get(proxy.PeerHeader) != tc.peer {
+			asked := standIn.question(t)
+			if asked.header.Get(servewaf.ClientHeader) != tc.client ||
+				asked.header.Get(servewaf.PeerHeader) != tc.peer {
 				t.Errorf("the question's headers are %v", asked.header)
 			}
 

internal/rproxy/request.go

@@ -16,9 +16,9 @@ import (
 	"sync/atomic"
 	"time"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rules"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // flushAfterEachWrite has ReverseProxy pass on each part of the app's answer as
@@ -129,7 +129,7 @@ func (rq *request) readFirstPartOfBody() bool {
 	}
 
 	_ = rq.rc.SetReadDeadline(rq.requestDeadline())
-	held, err := io.ReadAll(io.LimitReader(rq.body, proxy.QuestionBodyMaxBytes))
+	held, err := io.ReadAll(io.LimitReader(rq.body, servewaf.QuestionBodyMaxBytes))
 	// From here on, the request timer ends a read of the rest of the body, so that
 	// the answer can name the side rproxy was waiting on.
 	_ = rq.rc.SetReadDeadline(time.Time{})
@@ -384,7 +384,7 @@ func (rq *request) finish(ctx context.Context) {
 		return
 	}
 
-	report := &proxy.Report{
+	report := &servewaf.Report{
 		RequestID:     rq.id,
 		Status:        min(rq.out.status, reportStatusMax),
 		RequestBytes:  requestBytes,

internal/rproxy/rproxy.go

@@ -22,7 +22,7 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/config"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // How rproxy keeps connections to the app and to servewaf open between
@@ -85,7 +85,7 @@ func New(params Params) *Server {
 		transport:         newTransport(),
 		serveWAFTransport: newServeWAFTransport(),
 		reportURL: (&url.URL{
-			Scheme: backend.Scheme, Host: backend.Host, Path: proxy.ReportPath,
+			Scheme: backend.Scheme, Host: backend.Host, Path: servewaf.ReportPath,
 		}).String(),
 	}
 
@@ -166,7 +166,7 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	rq := h.newRequest(w, r)
 	defer rq.finish(r.Context())
 
-	if r.Method == http.MethodGet && r.URL.Path == proxy.HealthPath {
+	if r.Method == http.MethodGet && r.URL.Path == servewaf.HealthPath {
 		rq.answerHealth()
 
 		return
@@ -199,9 +199,9 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	rq.noteAnswer(answer)
 
 	switch rq.disposition {
-	case proxy.DispositionAllow:
+	case servewaf.DispositionAllow:
 		rq.passToApp(r.Context())
-	case proxy.DispositionClose:
+	case servewaf.DispositionClose:
 		// This panic has Go's server close the connection without an answer,
 		// and log nothing; the deferred finish still runs.
 		panic(http.ErrAbortHandler)

internal/rproxy/rproxy_test.go

@@ -19,9 +19,9 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/config"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rproxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -54,7 +54,7 @@ const (
 
 // The headers the tests set and look at.
 const (
-	dispositionHeader    = proxy.DispositionHeader
+	dispositionHeader    = servewaf.DispositionHeader
 	forwardedForHeader   = "X-Forwarded-For"
 	forwardedProtoHeader = "X-Forwarded-Proto"
 	requestIDHeader      = "X-Request-ID"
@@ -70,9 +70,9 @@ const (
 
 // What the stand-in for servewaf answers.
 const (
-	dispositionAllow = proxy.DispositionAllow
-	dispositionDeny  = proxy.DispositionDeny
-	dispositionClose = proxy.DispositionClose
+	dispositionAllow = servewaf.DispositionAllow
+	dispositionDeny  = servewaf.DispositionDeny
+	dispositionClose = servewaf.DispositionClose
 	// deniedBody is the body of a deny.
 	deniedBody = "refused by servewaf"
 )
@@ -173,7 +173,7 @@ type serveWAF struct {
 	*httptest.Server
 
 	questions chan question
-	reports   chan proxy.Report
+	reports   chan servewaf.Report
 }
 
 // startServeWAF starts a stand-in for servewaf.
@@ -182,11 +182,11 @@ func startServeWAF(t *testing.T, answer http.HandlerFunc) *serveWAF {
 
 	s := &serveWAF{
 		questions: make(chan question, 10),
-		reports:   make(chan proxy.Report, 10),
+		reports:   make(chan servewaf.Report, 10),
 	}
 	s.Server = httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
-			if r.Header.Get(proxy.ClientHeader) == "" {
+			if r.Header.Get(servewaf.ClientHeader) == "" {
 				s.takeReport(t, w, r)
 
 				return
@@ -213,10 +213,10 @@ func startServeWAF(t *testing.T, answer http.HandlerFunc) *serveWAF {
 func (s *serveWAF) takeReport(t *testing.T, w http.ResponseWriter, r *http.Request) {
 	t.Helper()
 
-	var report proxy.Report
+	var report servewaf.Report
 
 	err := json.NewDecoder(r.Body).Decode(&report)
-	if err != nil || r.Method != http.MethodPost || r.URL.Path != proxy.ReportPath {
+	if err != nil || r.Method != http.MethodPost || r.URL.Path != servewaf.ReportPath {
 		t.Errorf("%s %s is no report: %v", r.Method, r.URL.Path, err)
 	}
 
@@ -237,7 +237,7 @@ func (s *serveWAF) wantNoReport(t *testing.T) {
 }
 
 // report waits for a report.
-func (s *serveWAF) report(t *testing.T) proxy.Report {
+func (s *serveWAF) report(t *testing.T) servewaf.Report {
 	t.Helper()
 
 	select {
@@ -246,7 +246,7 @@ func (s *serveWAF) report(t *testing.T) proxy.Report {
 	case <-time.After(waitLimit):
 		t.Fatal("no report")
 
-		return proxy.Report{}
+		return servewaf.Report{}
 	}
 }
 
@@ -273,7 +273,7 @@ func startServeWAFAnsweringReports(
 
 	backend := httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
-			if r.Header.Get(proxy.ClientHeader) != "" {
+			if r.Header.Get(servewaf.ClientHeader) != "" {
 				answer(w, r)
 
 				return
@@ -498,7 +498,7 @@ func readStatus(t *testing.T, conn net.Conn) int {
 func TestPassesAnAllowedRequestToTheAppAndItsAnswerBack(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, func(w http.ResponseWriter, r *http.Request) {
+	standIn := startServeWAF(t, func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set(asnHeader, "AS64496")
 		w.Header().Set(countryHeader, "DE")
 		allow(w, r)
@@ -512,7 +512,7 @@ func TestPassesAnAllowedRequestToTheAppAndItsAnswerBack(t *testing.T) {
 		w.WriteHeader(http.StatusTeapot)
 		_, _ = io.WriteString(w, greeting)
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	const target = pathGoReencodes + "?b=2&a=1&bad=%zz;x"
 
@@ -530,7 +530,7 @@ func TestPassesAnAllowedRequestToTheAppAndItsAnswerBack(t *testing.T) {
 	}
 
 	received := <-seen
-	asked := servewaf.question(t)
+	asked := standIn.question(t)
 
 	if received.RequestURI != target || received.Host != site {
 		t.Errorf("the app saw %s for %s", received.RequestURI, received.Host)
@@ -557,14 +557,14 @@ func TestAPeerNotTrustedHasItsForwardedHeadersReplaced(t *testing.T) {
 		"X-Forwarded-Tls-Client-Cert-Info", "X-Real-Ip",
 	}
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	seen := make(chan http.Header, 1)
 	app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
 		seen <- r.Header.Clone()
 
 		greet(w, r)
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		trustedProxies: "10.0.0.0/8",
 	})
 
@@ -602,14 +602,14 @@ func TestAPeerNotTrustedHasItsForwardedHeadersReplaced(t *testing.T) {
 func TestATrustedProxysForwardedHeadersPassOn(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	seen := make(chan http.Header, 1)
 	app := startApp(t, func(w http.ResponseWriter, r *http.Request) {
 		seen <- r.Header.Clone()
 
 		greet(w, r)
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		trustedProxies: localhost + "/32",
 	})
 
@@ -641,12 +641,12 @@ func TestATrustedProxysForwardedHeadersPassOn(t *testing.T) {
 func TestAnAnswerWithoutAContentTypeGetsNone(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 		w.Header()["Content-Type"] = nil
 		_, _ = io.WriteString(w, "<html>")
 	})
-	_, _, server := startServer(t, servewaf.URL, app.URL, nil)
+	_, _, server := startServer(t, standIn.URL, app.URL, nil)
 
 	req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", http.NoBody)
 	w := httptest.NewRecorder()
@@ -704,11 +704,11 @@ func TestRemovesTheVisitorsLookupHeadersWhenServeWAFGivesNone(t *testing.T) {
 func TestDenyGivesTheVisitorServeWAFsAnswer(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, deny)
+	standIn := startServeWAF(t, deny)
 	app := startApp(t, func(http.ResponseWriter, *http.Request) {
 		t.Error("the app was asked")
 	})
-	addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 	got := get(t, addr, "/")
 	if got.status != http.StatusForbidden || got.body != deniedBody ||
@@ -720,7 +720,7 @@ func TestDenyGivesTheVisitorServeWAFsAnswer(t *testing.T) {
 		t.Errorf("the visitor got %s", dispositionHeader)
 	}
 
-	report := servewaf.report(t)
+	report := standIn.report(t)
 	if report.Status != http.StatusForbidden ||
 		report.ResponseBytes != int64(len(deniedBody)) ||
 		report.DurationUpstreamTotal != 0 {
@@ -736,9 +736,9 @@ func TestDenyGivesTheVisitorServeWAFsAnswer(t *testing.T) {
 func TestADeniedHeadKeepsServeWAFsContentLength(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, deny)
+	standIn := startServeWAF(t, deny)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	got := visit(t, newRequest(t, http.MethodHead, addr, "/", http.NoBody))
 	if got.status != http.StatusForbidden ||
@@ -758,15 +758,15 @@ func TestAnAnswerRProxyHoldsWholeIsSentBeforeItsLogLine(t *testing.T) {
 	}{
 		{"a deny", "GET /" + host, deniedBody, http.StatusForbidden},
 		{"rproxy's own answer", "GET x:admin" + host, "Bad Request\n", http.StatusBadRequest},
-		{"the health check", "GET " + proxy.HealthPath + host, "ok\n", http.StatusOK},
+		{"the health check", "GET " + servewaf.HealthPath + host, "ok\n", http.StatusOK},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
 			log := heldLog{release: make(chan struct{})}
-			servewaf := startServeWAF(t, deny)
+			standIn := startServeWAF(t, deny)
 			app := startApp(t, greet)
-			addr, _ := startServerLogging(t, servewaf.URL, app.URL, nil, log, io.Discard)
+			addr, _ := startServerLogging(t, standIn.URL, app.URL, nil, log, io.Discard)
 
 			t.Cleanup(func() { close(log.release) })
 
@@ -794,9 +794,9 @@ func TestAnAnswerRProxyHoldsWholeIsSentBeforeItsLogLine(t *testing.T) {
 func TestRProxysOwnAnswerIsPlainText(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	conn := dial(t, addr)
 	send(t, conn, "GET x:admin HTTP/1.1\r\nHost: site.example\r\n\r\n")
@@ -817,14 +817,14 @@ func TestRProxysOwnAnswerIsPlainText(t *testing.T) {
 func TestCloseClosesTheConnectionWithoutAnAnswer(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
+	standIn := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
 		w.Header().Set(dispositionHeader, dispositionClose)
 		w.WriteHeader(http.StatusOK)
 	})
 	app := startApp(t, func(http.ResponseWriter, *http.Request) {
 		t.Error("the app was asked")
 	})
-	addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 	conn := dial(t, addr)
 	send(t, conn, "GET / HTTP/1.1\r\nHost: site.example\r\n\r\n")
@@ -835,7 +835,7 @@ func TestCloseClosesTheConnectionWithoutAnAnswer(t *testing.T) {
 			text, err)
 	}
 
-	report := servewaf.report(t)
+	report := standIn.report(t)
 	if report.Status != 0 || report.ResponseBytes != 0 {
 		t.Errorf("report %+v, of a visitor sent nothing", report)
 	}
@@ -935,7 +935,7 @@ func TestAnAnswerOtherThanAllowGoesToTheVisitorAsServeWAFGaveIt(t *testing.T) {
 			t.Run(tc.name+" with the default "+setting, func(t *testing.T) {
 				t.Parallel()
 
-				servewaf := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
+				standIn := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
 					if tc.disposition != "" {
 						w.Header().Set(dispositionHeader, tc.disposition)
 					}
@@ -947,7 +947,7 @@ func TestAnAnswerOtherThanAllowGoesToTheVisitorAsServeWAFGaveIt(t *testing.T) {
 				app := startApp(t, func(http.ResponseWriter, *http.Request) {
 					t.Error("the app was asked")
 				})
-				addr, out := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+				addr, out := startRProxy(t, standIn.URL, app.URL, map[string]string{
 					defaultDisposition: setting,
 				})
 
@@ -977,11 +977,11 @@ func TestAnAnswerOtherThanAllowGoesToTheVisitorAsServeWAFGaveIt(t *testing.T) {
 func TestAnAnswerWithoutAValidDispositionGetsNoReport(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
+	standIn := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
 		http.Error(w, "refused", http.StatusBadRequest)
 	})
 	app := startApp(t, greet)
-	addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 	if got := get(t, addr, "/"); got.status != http.StatusBadRequest {
 		t.Errorf("answered %+v, want servewaf's 400", got)
@@ -991,18 +991,18 @@ func TestAnAnswerWithoutAValidDispositionGetsNoReport(t *testing.T) {
 		t.Errorf("line %v, want no disposition", line)
 	}
 
-	servewaf.wantNoReport(t)
+	standIn.wantNoReport(t)
 }
 
 func TestAnAnswerWithoutAContentTypeGoesToTheVisitorWithNone(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
+	standIn := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
 		w.Header()["Content-Type"] = nil
 		w.WriteHeader(http.StatusInternalServerError)
 		_, _ = io.WriteString(w, "<html>broken")
 	})
-	addr, _ := startRProxy(t, servewaf.URL, nowhere, nil)
+	addr, _ := startRProxy(t, standIn.URL, nowhere, nil)
 
 	got := get(t, addr, "/")
 	if contentType, sent := got.header["Content-Type"]; sent {
@@ -1015,11 +1015,11 @@ func TestAnAnswerOf1MiBGoesToTheVisitor(t *testing.T) {
 
 	const size = 1 << 20
 
-	servewaf := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
+	standIn := startServeWAF(t, func(w http.ResponseWriter, _ *http.Request) {
 		w.WriteHeader(http.StatusInternalServerError)
 		_, _ = w.Write(make([]byte, size))
 	})
-	addr, _ := startRProxy(t, servewaf.URL, nowhere, nil)
+	addr, _ := startRProxy(t, standIn.URL, nowhere, nil)
 
 	got := get(t, addr, "/")
 	if got.status != http.StatusInternalServerError || len(got.body) != size {
@@ -1135,15 +1135,15 @@ func TestAnAnswerThatCannotBePassedOnIsAnswered502(t *testing.T) {
 func TestAnAnswerThatCannotBePassedOnGetsNoReport(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, overOneMiB(dispositionDeny))
-	addr, out := startRProxy(t, servewaf.URL, nowhere, nil)
+	standIn := startServeWAF(t, overOneMiB(dispositionDeny))
+	addr, out := startRProxy(t, standIn.URL, nowhere, nil)
 
 	if got := get(t, addr, "/"); got.status != http.StatusBadGateway {
 		t.Errorf("answered %+v, want 502", got)
 	}
 
 	out.requestLine(t)
-	servewaf.wantNoReport(t)
+	standIn.wantNoReport(t)
 }
 
 func TestWithoutAnAnswerTheDefaultDispositionDecides(t *testing.T) {
@@ -1199,20 +1199,20 @@ func TestAVisitorThatGoesAwayWhileServeWAFIsAskedGetsNoDefault(t *testing.T) {
 		t.Run("with the default "+disposition, func(t *testing.T) {
 			t.Parallel()
 
-			servewaf := startServeWAF(t, func(_ http.ResponseWriter, r *http.Request) {
+			standIn := startServeWAF(t, func(_ http.ResponseWriter, r *http.Request) {
 				<-r.Context().Done()
 			})
 			app := startApp(t, func(http.ResponseWriter, *http.Request) {
 				t.Error("the app was asked")
 			})
-			addr, out := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+			addr, out := startRProxy(t, standIn.URL, app.URL, map[string]string{
 				timeoutSetting:     "60000",
 				defaultDisposition: disposition,
 			})
 
 			conn := dial(t, addr)
 			send(t, conn, "GET / HTTP/1.1\r\nHost: site.example\r\n\r\n")
-			servewaf.question(t)
+			standIn.question(t)
 
 			_ = conn.Close()
 
@@ -1226,7 +1226,7 @@ func TestAVisitorThatGoesAwayWhileServeWAFIsAskedGetsNoDefault(t *testing.T) {
 				t.Error("rproxy warned that servewaf gave no answer")
 			}
 
-			servewaf.wantNoReport(t)
+			standIn.wantNoReport(t)
 		})
 	}
 }
@@ -1244,17 +1244,17 @@ func TestRProxyWarnsWhenTheDefaultDecides(t *testing.T) {
 func TestSendsNoReportWithoutAnAnswer(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, func(_ http.ResponseWriter, r *http.Request) {
+	standIn := startServeWAF(t, func(_ http.ResponseWriter, r *http.Request) {
 		<-r.Context().Done()
 	})
 	app := startApp(t, greet)
-	addr, out := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, out := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		timeoutSetting: "200",
 	})
 
 	wantGreeting(t, get(t, addr, "/"))
 	out.requestLine(t)
-	servewaf.wantNoReport(t)
+	standIn.wantNoReport(t)
 }
 
 func TestAPathUnderOwnPrefixNeverReachesTheApp(t *testing.T) {
@@ -1274,25 +1274,25 @@ func TestAPathUnderOwnPrefixNeverReachesTheApp(t *testing.T) {
 func TestHealthCheckIsAnsweredWhileServeWAFIsDown(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
 	addr, out := startRProxy(t, nowhere, app.URL, nil)
 
-	got := get(t, addr, proxy.HealthPath)
+	got := get(t, addr, servewaf.HealthPath)
 	if got.status != http.StatusOK || got.body != "ok\n" {
 		t.Errorf("answered %+v, want ok", got)
 	}
 
 	line := out.requestLine(t)
-	if line["path"] != proxy.HealthPath || line["disposition"] != nil {
+	if line["path"] != servewaf.HealthPath || line["disposition"] != nil {
 		t.Errorf("line %v, want one with no disposition", line)
 	}
 
 	// With servewaf up too, it is not asked.
-	addr, _ = startRProxy(t, servewaf.URL, app.URL, nil)
-	get(t, addr, proxy.HealthPath)
+	addr, _ = startRProxy(t, standIn.URL, app.URL, nil)
+	get(t, addr, servewaf.HealthPath)
 
-	if len(servewaf.questions) != 0 {
+	if len(standIn.questions) != 0 {
 		t.Error("servewaf was asked about the health check")
 	}
 }
@@ -1353,8 +1353,10 @@ func TestAReportServeWAFLeavesUnansweredIsDroppedAtTheTimeLimit(t *testing.T) {
 		})
 
 	app := startApp(t, greet)
+	// The time limit is long enough for a loaded host to answer the question before
+	// it runs out.
 	addr, out := startRProxy(t, backend, app.URL, map[string]string{
-		timeoutSetting: "1000",
+		timeoutSetting: "3000",
 	})
 
 	t.Cleanup(func() { close(release) })
@@ -1394,15 +1396,15 @@ func TestAReportAnswered101IsDroppedAtOnce(t *testing.T) {
 func TestAReportDueAfterWaitForReportsIsDropped(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, out, server := startServer(t, servewaf.URL, app.URL, nil)
+	addr, out, server := startServer(t, standIn.URL, app.URL, nil)
 
 	server.WaitForReports()
 
 	wantGreeting(t, get(t, addr, "/"))
 	out.requestLine(t)
-	servewaf.wantNoReport(t)
+	standIn.wantNoReport(t)
 }
 
 func TestReportGivesWhatHappened(t *testing.T) {
@@ -1410,14 +1412,14 @@ func TestReportGivesWhatHappened(t *testing.T) {
 
 	const body = "the visitor's body"
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 	wantGreeting(t, visit(t, newRequest(t, http.MethodPost, addr, "/",
 		strings.NewReader(body))))
 
-	report := servewaf.report(t)
+	report := standIn.report(t)
 
 	if report.RequestID == "" || report.Status != http.StatusOK ||
 		report.RequestBytes != int64(len(body)) ||
@@ -1440,7 +1442,7 @@ func TestWaitForReportsWaitsForAReportBeingSent(t *testing.T) {
 	release := make(chan struct{})
 	backend := httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
-			if r.Header.Get(proxy.ClientHeader) != "" {
+			if r.Header.Get(servewaf.ClientHeader) != "" {
 				allow(w, r)
 
 				return
@@ -1495,9 +1497,9 @@ func TestWaitForReportsWaitsForAReportBeingSent(t *testing.T) {
 func TestReportOfAWebSocketCountsWhatItCarried(t *testing.T) {
 	t.Parallel()
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, echoAfterUpgrade)
-	addr, out := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, out := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		maxRequestTime:  "2000",
 		maxResponseTime: "2000",
 	})
@@ -1533,7 +1535,7 @@ func TestReportOfAWebSocketCountsWhatItCarried(t *testing.T) {
 
 	_ = conn.Close()
 
-	report := servewaf.report(t)
+	report := standIn.report(t)
 	if report.Status != http.StatusSwitchingProtocols ||
 		report.RequestBytes != int64(len(message)) ||
 		report.ResponseBytes != int64(len(message)) {
@@ -1550,7 +1552,7 @@ func TestAWebSocketPassesOnThatTheVisitorStoppedSending(t *testing.T) {
 
 	const goodbye = "sent after the visitor stopped sending\n"
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 		conn, buffered, err := http.NewResponseController(w).Hijack()
 		if err != nil {
@@ -1570,7 +1572,7 @@ func TestAWebSocketPassesOnThatTheVisitorStoppedSending(t *testing.T) {
 		_, _ = buffered.WriteString(goodbye)
 		_ = buffered.Flush()
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	conn := dial(t, addr)
 	send(t, conn, "GET /socket HTTP/1.1\r\nHost: app\r\n"+
@@ -1608,7 +1610,7 @@ func TestAWebSocketPassesOnThatTheVisitorStoppedSending(t *testing.T) {
 //nolint:paralleltest // see above
 func TestASwitchNotPassedOnClosesTheAppsConnection(t *testing.T) {
 	closed := make(chan error, 1)
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, func(w http.ResponseWriter, _ *http.Request) {
 		conn, buffered, err := http.NewResponseController(w).Hijack()
 		if err != nil {
@@ -1631,7 +1633,7 @@ func TestASwitchNotPassedOnClosesTheAppsConnection(t *testing.T) {
 		_, err = buffered.ReadByte()
 		closed <- err
 	})
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, _ := startRProxy(t, standIn.URL, app.URL, nil)
 
 	conn := dial(t, addr)
 	send(t, conn, "GET /socket HTTP/1.1\r\nHost: app\r\n"+
@@ -1679,9 +1681,9 @@ func TestEachRequestGetsAFreshID(t *testing.T) {
 
 	const fromTraefik = "an-id-from-traefik"
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, _ := startRProxy(t, servewaf.URL, app.URL, map[string]string{
+	addr, _ := startRProxy(t, standIn.URL, app.URL, map[string]string{
 		trustedProxies: localhost + "/32",
 	})
 
@@ -1692,7 +1694,7 @@ func TestEachRequestGetsAFreshID(t *testing.T) {
 		req.Header.Set(requestIDHeader, fromTraefik)
 		wantGreeting(t, visit(t, req))
 
-		ids = append(ids, servewaf.question(t).header.Get(requestIDHeader))
+		ids = append(ids, standIn.question(t).header.Get(requestIDHeader))
 	}
 
 	if slices.Contains(ids, fromTraefik) || ids[0] == "" || ids[0] == ids[1] {
@@ -1709,16 +1711,16 @@ func TestLogLineGivesTheRequestAsSent(t *testing.T) {
 		body  = "the visitor's body"
 	)
 
-	servewaf := startServeWAF(t, allow)
+	standIn := startServeWAF(t, allow)
 	app := startApp(t, greet)
-	addr, out := startRProxy(t, servewaf.URL, app.URL, nil)
+	addr, out := startRProxy(t, standIn.URL, app.URL, nil)
 
 	req := newRequest(t, http.MethodPost, addr, path+"?"+query, strings.NewReader(body))
 	req.Host = site
 	wantGreeting(t, visit(t, req))
 
 	line := out.requestLine(t)
-	asked := servewaf.question(t)
+	asked := standIn.question(t)
 
 	for name, want := range map[string]any{
 		"type":           "request",

internal/rproxy/servewaf.go

@@ -11,7 +11,7 @@ import (
 	"net/http"
 	"strings"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // answerBodyMaxBytes is the most of the body of servewaf's answer that is read.
@@ -38,10 +38,10 @@ type servewafAnswer struct {
 // notes nothing, and no report is due for it: servewaf holds no decision to report
 // on.
 func (rq *request) noteAnswer(answer *servewafAnswer) {
-	disposition := answer.header.Get(proxy.DispositionHeader)
+	disposition := answer.header.Get(servewaf.DispositionHeader)
 
 	switch disposition {
-	case proxy.DispositionAllow, proxy.DispositionDeny, proxy.DispositionClose:
+	case servewaf.DispositionAllow, servewaf.DispositionDeny, servewaf.DispositionClose:
 		rq.disposition = disposition
 		rq.answered = true
 		rq.asn = answer.header.Get(asnHeader)
@@ -74,7 +74,7 @@ func (rq *request) handleNoUsableAnswer(ctx context.Context, err error) {
 		rq.disposition = rq.h.config.DefaultDisposition
 		rq.byDefault = true
 
-		if rq.disposition == proxy.DispositionAllow {
+		if rq.disposition == servewaf.DispositionAllow {
 			rq.passToApp(ctx)
 		} else {
 			rq.answer(http.StatusServiceUnavailable)
@@ -169,13 +169,13 @@ func (rq *request) newQuestion(ctx context.Context) (*http.Request, error) {
 	question.TransferEncoding = in.TransferEncoding
 
 	question.Header = in.Header.Clone()
-	question.Header.Set(proxy.ClientHeader, rq.client.String())
-	question.Header.Set(proxy.PeerHeader, rq.peer.String())
-	question.Header.Del(proxy.ContentLengthHeader)
+	question.Header.Set(servewaf.ClientHeader, rq.client.String())
+	question.Header.Set(servewaf.PeerHeader, rq.peer.String())
+	question.Header.Del(servewaf.ContentLengthHeader)
 
 	announced := in.Header.Get("Content-Length")
 	if announced != "" {
-		question.Header.Set(proxy.ContentLengthHeader, announced)
+		question.Header.Set(servewaf.ContentLengthHeader, announced)
 	}
 
 	question.Header.Set(requestIDHeader, rq.id)
@@ -196,7 +196,7 @@ func (rq *request) answerWith(answer *servewafAnswer) {
 
 	header := rq.out.Header()
 	maps.Copy(header, answer.header)
-	header.Del(proxy.DispositionHeader)
+	header.Del(servewaf.DispositionHeader)
 
 	// Go's server adds a Content-Type it guesses from the body to a response whose
 	// headers have no Content-Type key. The key with no value sends none.
@@ -210,7 +210,7 @@ func (rq *request) answerWith(answer *servewafAnswer) {
 // sendReport sends servewaf report on a goroutine of its own, so that the
 // visitor does not wait for it. The report goes on after ctx, the request's own
 // context, has ended.
-func (h *handler) sendReport(ctx context.Context, report *proxy.Report) {
+func (h *handler) sendReport(ctx context.Context, report *servewaf.Report) {
 	h.reportsMu.Lock()
 	defer h.reportsMu.Unlock()
 
@@ -228,7 +228,7 @@ func (h *handler) sendReport(ctx context.Context, report *proxy.Report) {
 
 // postReport posts report to servewaf, and waits for its answer for up to
 // SWRP_TIMEOUT_MS.
-func (h *handler) postReport(ctx context.Context, report *proxy.Report) error {
+func (h *handler) postReport(ctx context.Context, report *servewaf.Report) error {
 	body, err := json.Marshal(report)
 	if err != nil {
 		return fmt.Errorf("encode the report: %w", err)

internal/servewaf/abuseipdb.go

@@ -0,0 +1,55 @@
+package servewaf
+
+// The heuristic abuseipdb. It reads SWWAF_ABUSEIPDB_KEY,
+// SWWAF_ABUSEIPDB_MIN_SCORE and SWWAF_REPUTATION_ACTION.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
+	"sneak.berlin/go/smallwebwaf/internal/reputation"
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// abuseIPDB notes AbuseIPDB, as noteHit does, with the score, when its score
+// of the client is a hit, and refuses the request when SWWAF_REPUTATION_ACTION
+// is deny, as dnsbl does for a zone. While SWWAF_ABUSEIPDB_KEY is unset it does
+// nothing. A client without a score is checked in the background, by the
+// request's address, if its history counts an offence, and the request does
+// not wait for the answer. The score is then used for each address of the
+// client. Its figures are the score and SWWAF_ABUSEIPDB_MIN_SCORE.
+type abuseIPDB struct{}
+
+func (abuseIPDB) name() string { return "abuseipdb" }
+
+func (abuseIPDB) check(ctx context.Context, rq *request, _ time.Time) *verdict {
+	if rq.h.config.AbuseIPDBKey == "" {
+		return nil
+	}
+
+	client := rq.h.clientGroup(rq.client)
+	held, _ := rq.h.limiter.Client(client)
+	offender := held.History.Offences != ratelimit.Offences{}
+
+	score, hit := rq.h.abuseIPDB.Hit(ctx, client, rq.client, offender)
+	if !hit {
+		return nil
+	}
+
+	rq.abuseIPDBHit = true
+	rq.noteHit(bans.ReputationHit{Source: reputation.AbuseIPDBSource, Score: &score},
+		"scored by AbuseIPDB at or over SWWAF_ABUSEIPDB_MIN_SCORE")
+
+	if rq.h.config.ReputationAction != deny {
+		return nil
+	}
+
+	return &verdict{
+		action: requestlog.ActionDenied,
+		figures: map[string]any{
+			figureScore: score, "min_score": rq.h.config.AbuseIPDBMinScore,
+		},
+	}
+}

internal/servewaf/admin.go

@@ -1,4 +1,4 @@
-package proxy
+package servewaf
 
 import (
 	"bytes"

internal/servewaf/admin_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"encoding/json"
@@ -10,9 +10,9 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 	"sneak.berlin/go/smallwebwaf/internal/state"
 )
 
@@ -88,11 +88,11 @@ func TestAdminEndpointsNeedTheAdminToken(t *testing.T) {
 
 	// Any other request under /_smallwebwaf/ is not found.
 	for _, e := range []adminEndpoint{
-		{http.MethodPut, proxy.BansPath, banOtherClient},
-		{http.MethodDelete, proxy.BansPath, ""},
-		{http.MethodGet, proxy.BansPath + "/" + otherClient, ""},
-		{http.MethodPost, proxy.ClientsPath + otherClient, ""},
-		{http.MethodGet, strings.TrimSuffix(proxy.ClientsPath, "/"), ""},
+		{http.MethodPut, servewaf.BansPath, banOtherClient},
+		{http.MethodDelete, servewaf.BansPath, ""},
+		{http.MethodGet, servewaf.BansPath + "/" + otherClient, ""},
+		{http.MethodPost, servewaf.ClientsPath + otherClient, ""},
+		{http.MethodGet, strings.TrimSuffix(servewaf.ClientsPath, "/"), ""},
 	} {
 		s.admin(e.method, e.path, e.body, http.StatusNotFound)
 	}
@@ -118,7 +118,7 @@ func TestBanAddedListedAndLiftedThroughTheEndpoints(t *testing.T) {
 		Reason:   "probes for logins",
 	}
 
-	wantBans(t, s.admin(http.MethodPost, proxy.BansPath, banOtherClient, http.StatusOK),
+	wantBans(t, s.admin(http.MethodPost, servewaf.BansPath, banOtherClient, http.StatusOK),
 		want)
 
 	line := s.get(client, http.StatusForbidden, requestlog.ActionBanned)
@@ -129,7 +129,7 @@ func TestBanAddedListedAndLiftedThroughTheEndpoints(t *testing.T) {
 	// Its notes count the request it refused.
 	want.Notes.Requests, want.Notes.Refused = 1, 1
 
-	wantBans(t, s.admin(http.MethodGet, proxy.BansPath, "", http.StatusOK), want)
+	wantBans(t, s.admin(http.MethodGet, servewaf.BansPath, "", http.StatusOK), want)
 
 	// Ten minutes on, lifting the bans on client lifts that one, which is
 	// kept, marked lifted.
@@ -138,13 +138,13 @@ func TestBanAddedListedAndLiftedThroughTheEndpoints(t *testing.T) {
 	lifted := clk.Now()
 	want.Lifted = &lifted
 
-	wantBans(t, s.admin(http.MethodDelete, proxy.BansPath+"/"+client, "",
+	wantBans(t, s.admin(http.MethodDelete, servewaf.BansPath+"/"+client, "",
 		http.StatusOK), want)
 	s.get(client, http.StatusOK, requestlog.ActionForward)
-	wantBans(t, s.admin(http.MethodGet, proxy.BansPath, "", http.StatusOK), want)
+	wantBans(t, s.admin(http.MethodGet, servewaf.BansPath, "", http.StatusOK), want)
 
 	// No ban on it is active any more.
-	s.admin(http.MethodDelete, proxy.BansPath+"/"+client, "", http.StatusNotFound)
+	s.admin(http.MethodDelete, servewaf.BansPath+"/"+client, "", http.StatusNotFound)
 }
 
 func TestBanToAddGivesItsNetblockAndDuration(t *testing.T) {
@@ -181,7 +181,7 @@ func TestBanToAddGivesItsNetblockAndDuration(t *testing.T) {
 			want.Expires = &expires
 		}
 
-		wantBans(t, s.admin(http.MethodPost, proxy.BansPath, body, http.StatusOK), want)
+		wantBans(t, s.admin(http.MethodPost, servewaf.BansPath, body, http.StatusOK), want)
 	}
 }
 
@@ -250,7 +250,7 @@ func TestBanToAddThatCannotBeReadIsRefused(t *testing.T) {
 			"request body too large",
 		},
 	} {
-		got := s.admin(http.MethodPost, proxy.BansPath, tc.body, http.StatusBadRequest)
+		got := s.admin(http.MethodPost, servewaf.BansPath, tc.body, http.StatusBadRequest)
 		if !strings.Contains(string(got.body), tc.want) {
 			t.Errorf("%.80s was answered %q, want it to say %q", tc.body, got.body, tc.want)
 		}
@@ -283,7 +283,7 @@ func TestClientEndpointShowsTheClientAndItsBans(t *testing.T) {
 			Bans   []state.BanEntry  `json:"bans"`
 		}
 
-		decode(t, s.admin(http.MethodGet, proxy.ClientsPath+addr, "", http.StatusOK), &got)
+		decode(t, s.admin(http.MethodGet, servewaf.ClientsPath+addr, "", http.StatusOK), &got)
 
 		if got.Client == nil {
 			t.Fatalf("%s: no client", addr)
@@ -305,13 +305,13 @@ func TestClientEndpointShowsTheClientAndItsBans(t *testing.T) {
 
 	// Of an address no request came from and no ban covers, nothing is
 	// known.
-	got := s.admin(http.MethodGet, proxy.ClientsPath+"198.51.100.99", "", http.StatusOK)
+	got := s.admin(http.MethodGet, servewaf.ClientsPath+"198.51.100.99", "", http.StatusOK)
 	if string(got.body) != "{\n    \"client\": null,\n    \"bans\": []\n}\n" {
 		t.Errorf("an unknown client is answered\n%s", got.body)
 	}
 
-	s.admin(http.MethodGet, proxy.ClientsPath+"203.0.113", "", http.StatusBadRequest)
-	s.admin(http.MethodDelete, proxy.BansPath+"/203.0.113.0/24", "",
+	s.admin(http.MethodGet, servewaf.ClientsPath+"203.0.113", "", http.StatusBadRequest)
+	s.admin(http.MethodDelete, servewaf.BansPath+"/203.0.113.0/24", "",
 		http.StatusBadRequest)
 }
 
@@ -342,10 +342,10 @@ type adminEndpoint struct {
 // bans on otherClient, and asking about otherClient.
 func adminEndpoints() []adminEndpoint {
 	return []adminEndpoint{
-		{http.MethodGet, proxy.BansPath, ""},
-		{http.MethodPost, proxy.BansPath, banOtherClient},
-		{http.MethodDelete, proxy.BansPath + "/" + otherClient, ""},
-		{http.MethodGet, proxy.ClientsPath + otherClient, ""},
+		{http.MethodGet, servewaf.BansPath, ""},
+		{http.MethodPost, servewaf.BansPath, banOtherClient},
+		{http.MethodDelete, servewaf.BansPath + "/" + otherClient, ""},
+		{http.MethodGet, servewaf.ClientsPath + otherClient, ""},
 	}
 }
 

internal/servewaf/alerts_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"maps"
@@ -10,8 +10,8 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -201,7 +201,7 @@ func TestObserveModeWorksOutABanOnlyWhenItsAlertWouldBeSent(t *testing.T) {
 // never sent them, and returns the queue they wait in as well.
 func startWithAlerts(
 	t *testing.T, env map[string]string,
-) (*sender, *clock, *proxy.Server, *alerts.Queue) {
+) (*sender, *clock, *servewaf.Server, *alerts.Queue) {
 	t.Helper()
 
 	return startAppWithAlerts(t, func(http.ResponseWriter, *http.Request) {}, env)
@@ -210,7 +210,7 @@ func startWithAlerts(
 // startAppWithAlerts is startWithAlerts in front of the app handler.
 func startAppWithAlerts(
 	t *testing.T, handler http.HandlerFunc, env map[string]string,
-) (*sender, *clock, *proxy.Server, *alerts.Queue) {
+) (*sender, *clock, *servewaf.Server, *alerts.Queue) {
 	t.Helper()
 
 	app := startApp(t, handler)

internal/servewaf/anomaly_internal_test.go

@@ -1,4 +1,4 @@
-package proxy
+package servewaf
 
 import (
 	"net/netip"

internal/servewaf/anomaly_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"maps"
@@ -13,9 +13,9 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/anomaly"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // The anomaly thresholds: the prefix of a scope followed by the end of a
@@ -319,7 +319,7 @@ func TestRequestCountsForTheASNumberGeoJSGivesBeforeItEnds(t *testing.T) {
 	// kept.
 	geojsURL, _, release := startHeldGeoJS(t)
 
-	var server atomic.Pointer[proxy.Server]
+	var server atomic.Pointer[servewaf.Server]
 
 	app := startApp(t, func(http.ResponseWriter, *http.Request) {
 		release()

internal/servewaf/answertime_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"fmt"
@@ -16,10 +16,10 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
 	"sneak.berlin/go/smallwebwaf/internal/lookup"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -81,7 +81,7 @@ func TestSixteenThousandCookiesAreRefusedWellWithinTheTimeLimit(t *testing.T) {
 		t.Errorf("answered after %s, want well within %s", took, answerTimeLimit)
 	}
 
-	wantDisposition(t, got, tooLarge, proxy.DispositionDeny)
+	wantDisposition(t, got, tooLarge, servewaf.DispositionDeny)
 
 	line := s.out.requestLine(t)
 	wantLine(t, line, tooLarge, requestlog.ActionTooLarge)
@@ -91,6 +91,18 @@ func TestSixteenThousandCookiesAreRefusedWellWithinTheTimeLimit(t *testing.T) {
 	}
 }
 
+func TestHeaderLimitRefusalNamesItsHeuristicCountsAndLimits(t *testing.T) {
+	t.Parallel()
+
+	s := startServeWAF(t, "", nil)
+	req := s.question(siteA, client, "/")
+	fillHeaders(req, headerFieldLimit+1)
+	do(t, req)
+
+	wantHeuristic(t, s.out.requestLine(t), "header_limits",
+		`{"fields": 101, "fields_limit": 100, "cookies": 0, "cookies_limit": 50}`)
+}
+
 func TestEachHeaderLimitRefusesARequestOverIt(t *testing.T) {
 	t.Parallel()
 
@@ -144,13 +156,13 @@ func TestEachHeaderLimitRefusesARequestOverIt(t *testing.T) {
 			line := s.out.requestLine(t)
 
 			if tc.refused {
-				wantDisposition(t, got, tooLarge, proxy.DispositionDeny)
+				wantDisposition(t, got, tooLarge, servewaf.DispositionDeny)
 				wantLine(t, line, tooLarge, requestlog.ActionTooLarge)
 
 				return
 			}
 
-			wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+			wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 			wantLine(t, line, http.StatusOK, requestlog.ActionForward)
 
 			if line.DurationWAF == nil {
@@ -175,7 +187,7 @@ func TestHeaderLimitsHoldWhateverTheCoreRuleSetSettingsSay(t *testing.T) {
 			req := s.question(siteA, client, "/")
 			req.Header.Set(cookieHeader, cookies(cookieLimit+1))
 
-			wantDisposition(t, do(t, req), tooLarge, proxy.DispositionDeny)
+			wantDisposition(t, do(t, req), tooLarge, servewaf.DispositionDeny)
 		})
 	}
 }
@@ -187,7 +199,7 @@ func TestClientInTheAllowNetsSkipsTheHeaderLimits(t *testing.T) {
 	req := s.question(siteA, client, "/")
 	req.Header.Set(cookieHeader, cookies(cookieLimit+1))
 
-	wantDisposition(t, do(t, req), http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, do(t, req), http.StatusOK, servewaf.DispositionAllow)
 }
 
 func TestObserveModeAllowsARequestOverTheHeaderLimitsUnread(t *testing.T) {
@@ -204,7 +216,7 @@ func TestObserveModeAllowsARequestOverTheHeaderLimitsUnread(t *testing.T) {
 		t.Errorf("answered after %s, want well within %s", took, answerTimeLimit)
 	}
 
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 
 	line := s.out.requestLine(t)
 	if line.WouldAction != requestlog.ActionTooLarge || line.DurationWAF != nil {
@@ -224,8 +236,8 @@ func TestRequestsOverTheHeaderLimitsCountTowardTheRateLimits(t *testing.T) {
 		return do(t, req)
 	}
 
-	wantDisposition(t, ask(), tooLarge, proxy.DispositionDeny)
-	wantDisposition(t, ask(), http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, ask(), tooLarge, servewaf.DispositionDeny)
+	wantDisposition(t, ask(), http.StatusForbidden, servewaf.DispositionDeny)
 
 	lines := s.out.requestLines(t, 2)
 	wantLine(t, lines[1], http.StatusForbidden, requestlog.ActionRateLimited)
@@ -249,7 +261,7 @@ func TestTheHeaderLimitsComeAfterTheTrapPathsAndTheRuleFiles(t *testing.T) {
 			req := s.question(siteA, client, tc.path)
 			req.Header.Set(cookieHeader, cookies(cookieLimit+1))
 
-			wantDisposition(t, do(t, req), http.StatusForbidden, proxy.DispositionDeny)
+			wantDisposition(t, do(t, req), http.StatusForbidden, servewaf.DispositionDeny)
 			wantLine(t, s.out.requestLine(t), http.StatusForbidden, tc.action)
 		})
 	}
@@ -265,7 +277,7 @@ func TestNotWaitingForGeoJSNeverLowersAClientsLimit(t *testing.T) {
 	req := s.question(siteA, fromDE, "/")
 	req.Header.Set(cookieHeader, cookies(cookieLimit+1))
 
-	wantDisposition(t, do(t, req), tooLarge, proxy.DispositionDeny)
+	wantDisposition(t, do(t, req), tooLarge, servewaf.DispositionDeny)
 
 	line := s.out.requestLine(t)
 	wantLine(t, line, tooLarge, requestlog.ActionTooLarge)
@@ -275,7 +287,7 @@ func TestNotWaitingForGeoJSNeverLowersAClientsLimit(t *testing.T) {
 	}
 
 	// The client is under no ban, and GeoJS places it in a country.
-	wantDisposition(t, s.ask(fromDE, "/"), http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, s.ask(fromDE, "/"), http.StatusOK, servewaf.DispositionAllow)
 }
 
 func TestAClientGeoJSPlacedInNoCountryCountsAsUnknownWithoutWaiting(t *testing.T) {
@@ -291,7 +303,7 @@ func TestAClientGeoJSPlacedInNoCountryCountsAsUnknownWithoutWaiting(t *testing.T
 	req := s.question(siteA, client, "/")
 	req.Header.Set(cookieHeader, cookies(cookieLimit+1))
 
-	wantDisposition(t, do(t, req), http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, do(t, req), http.StatusForbidden, servewaf.DispositionDeny)
 	wantLine(t, s.out.requestLine(t), http.StatusForbidden, requestlog.ActionRateLimited)
 }
 
@@ -306,7 +318,7 @@ func TestObserveModeWaitsForGeoJSForARequestOverTheHeaderLimits(t *testing.T) {
 	req.Header.Set(cookieHeader, cookies(cookieLimit+1))
 
 	got := do(t, req)
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 
 	asn, country := got.header.Get("X-Client-Asn"), got.header.Get("X-Client-Country")
 	if asn != asnDE || country != "DE" {
@@ -318,7 +330,9 @@ func TestObserveModeWaitsForGeoJSForARequestOverTheHeaderLimits(t *testing.T) {
 // newServeWAFInBubble makes a servewaf for a synctest bubble: GeoJS never
 // answers, a setting needs its answer, and everything is at its default but
 // for env. No request to it may use the network.
-func newServeWAFInBubble(t *testing.T, env map[string]string) (*proxy.Server, *output) {
+func newServeWAFInBubble(
+	t *testing.T, env map[string]string,
+) (*servewaf.Server, *output) {
 	t.Helper()
 
 	settings := map[string]string{deniedCountries: "KP"}
@@ -332,13 +346,13 @@ func newServeWAFInBubble(t *testing.T, env map[string]string) (*proxy.Server, *o
 // askDirectly hands a question about a request from client straight to server,
 // as change leaves it, and returns the answer's status and how long it took.
 func askDirectly(
-	t *testing.T, server *proxy.Server, change func(*http.Request),
+	t *testing.T, server *servewaf.Server, change func(*http.Request),
 ) (int, time.Duration) {
 	t.Helper()
 
 	req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", http.NoBody)
 	req.RemoteAddr = net.JoinHostPort(rproxyPeer, "1234")
-	req.Header.Set(proxy.ClientHeader, client)
+	req.Header.Set(servewaf.ClientHeader, client)
 	req.Header.Set(requestIDHeader, "the-id")
 	change(req)
 
@@ -351,17 +365,17 @@ func askDirectly(
 }
 
 // banClient bans client at now.
-func banClient(_ *testing.T, server *proxy.Server, now time.Time) {
+func banClient(_ *testing.T, server *servewaf.Server, now time.Time) {
 	server.Ledger.BanForLimit(netip.MustParsePrefix(client+"/32"), now, bans.Notes{})
 }
 
 // countClient counts one request from client at now for the rate limits.
-func countClient(_ *testing.T, server *proxy.Server, now time.Time) {
+func countClient(_ *testing.T, server *servewaf.Server, now time.Time) {
 	server.Limiter.Count(netip.MustParsePrefix(client+"/32"), now, wholeLimit)
 }
 
 // listClient puts client on the blocklist at dropURL.
-func listClient(t *testing.T, server *proxy.Server, now time.Time) {
+func listClient(t *testing.T, server *servewaf.Server, now time.Time) {
 	t.Helper()
 
 	err := server.Lists.Load([]reputation.List{{
@@ -373,13 +387,13 @@ func listClient(t *testing.T, server *proxy.Server, now time.Time) {
 }
 
 // decideOnClient puts client on the CrowdSec decision list.
-func decideOnClient(t *testing.T, server *proxy.Server, now time.Time) {
+func decideOnClient(t *testing.T, server *servewaf.Server, now time.Time) {
 	t.Helper()
 	loadDecisions(t, server, now, clientsDecision)
 }
 
 // leaveAsItIs prepares nothing.
-func leaveAsItIs(*testing.T, *proxy.Server, time.Time) {}
+func leaveAsItIs(*testing.T, *servewaf.Server, time.Time) {}
 
 func TestARefusedRequestDoesNotWaitForASlowGeoJS(t *testing.T) {
 	t.Parallel()
@@ -390,7 +404,7 @@ func TestARefusedRequestDoesNotWaitForASlowGeoJS(t *testing.T) {
 		name string
 		env  map[string]string
 		// prepare gets the server ready, at now, before the question.
-		prepare func(t *testing.T, server *proxy.Server, now time.Time)
+		prepare func(t *testing.T, server *servewaf.Server, now time.Time)
 		// cookie is the request's Cookie header.
 		cookie string
 		status int
@@ -461,7 +475,7 @@ func TestAQuestionWaitsForASlowGeoJSOnlyAsLongAsTheDefaultSays(t *testing.T) {
 		name string
 		env  map[string]string
 		// prepare gets the server ready, at now, before the question.
-		prepare func(t *testing.T, server *proxy.Server, now time.Time)
+		prepare func(t *testing.T, server *servewaf.Server, now time.Time)
 		status  int
 		action  string
 	}{
@@ -519,10 +533,10 @@ func TestServeWAFAnswersWithinTheTimeLimitWhileEveryOutsideSourceHangs(t *testin
 
 	t.Cleanup(func() { _ = resolver.Close() })
 
-	server, out, _ := newServeWAFWith(t, func(params proxy.Params) *proxy.Server {
+	server, out, _ := newServeWAFWith(t, func(params servewaf.Params) *servewaf.Server {
 		params.AbuseIPDBURL = silentAbuseIPDBURL
 
-		return proxy.NewServeWAF(params)
+		return servewaf.New(params)
 	}, held, time.Now, map[string]string{
 		deniedCountries: "KP", wafMode: block,
 		dnsblZones: dnsblZone, dnsblResolver: resolver.LocalAddr().String(),

internal/servewaf/bans.go

@@ -1,7 +1,10 @@
-package proxy
+package servewaf
+
+// The heuristic active_ban, and the code that makes bans, which several
+// heuristics share. active_ban reads SWWAF_MODE; the bans are the ban ledger's.
 
 import (
-	"net/http"
+	"context"
 	"net/netip"
 	"time"
 
@@ -18,11 +21,15 @@ func (rq *request) banResponse(action string) *refusal {
 	return &refusal{status: rq.h.config.BanResponse, action: action}
 }
 
-// banned reports whether a ban on a netblock the client is in covers the
-// request at now, and notes for the log line when that ban ends. A
-// request that makes the ban permanent, or in observe mode would have,
-// raises the alert for it.
-func (rq *request) banned(now time.Time) bool {
+// activeBan refuses a client a ban covers: a ban on a netblock the client is
+// in, in force at now. It notes for the log line when that ban ends. A request
+// that makes the ban permanent, or in observe mode would have, raises the alert
+// for it. Its figures are the ban's netblock and when it ends.
+type activeBan struct{}
+
+func (activeBan) name() string { return "active_ban" }
+
+func (activeBan) check(_ context.Context, rq *request, now time.Time) *verdict {
 	check := rq.h.ledger.Check
 	if rq.h.config.Observe {
 		check = rq.h.ledger.Find // the ban refuses nothing, and stays as it is
@@ -38,85 +45,24 @@ func (rq *request) banned(now time.Time) bool {
 		rq.alertBan(ban)
 	}
 
-	return banned
-}
-
-// limitBroken counts the request for the rate limits at now, notes the
-// client's counts for the log line, and reports whether the request takes
-// the client over a rate limit, as its limit percentage lowers it, which
-// breaks it.
-func (rq *request) limitBroken(now time.Time) bool {
-	counts, hit, over := rq.h.limiter.Count(rq.h.clientGroup(rq.client), now,
-		rq.limitPercent.percent)
-	rq.line.Counts = counts
-
-	if over {
-		rq.banForLimit(now, hit, rq.h.config.BanResponse)
+	if !banned {
+		return nil
 	}
 
-	return over
-}
-
-// countBytes counts the request's bytes, as countedBytes gives them, for
-// the byte limits, once its report has come, and notes the client's byte totals
-// for the log line; its requests stay there as the rate limits counted them.
-// Only an allowed request has them counted, and only one the rate limits
-// counted; in observe mode, not one that enforce mode would have refused. Bytes
-// that take the client over a byte limit, as its limit percentage for the byte
-// limits lowers it, break it; the response was passed on whole.
-func (rq *request) countBytes() {
-	if !rq.counted || rq.line.WouldAction != "" {
-		return
-	}
-
-	now := rq.h.now()
-
-	counts, hit, over := rq.h.limiter.CountBytes(rq.h.clientGroup(rq.client), now,
-		rq.countedBytes(), rq.bytesPercent.percent)
-	rq.line.Counts.MinuteBytes = counts.MinuteBytes
-	rq.line.Counts.HourBytes = counts.HourBytes
-	rq.line.Counts.DayBytes = counts.DayBytes
-
-	if over {
-		rq.banForLimit(now, hit, rq.out.status)
+	return &verdict{
+		action: requestlog.ActionBanned,
+		figures: map[string]any{
+			figureNetblock: ban.Netblock.String(), "ban_expires": rq.line.BanExpires,
+		},
 	}
 }
 
-// countRefusal counts the request for the error burst once it has been
-// answered, if servewaf refused it after a rule file match, a trap path or a
-// Core Rule Set match, and in observe mode if enforce mode would have: more than
-// SWWAF_ERROR_BURST_THRESHOLD such refusals of the client within a minute
-// break a limit. A client in SWWAF_ALLOW_NETS, which the checks skip, is
-// not counted, and nothing is while the threshold is off.
-func (rq *request) countRefusal() {
-	cfg := rq.h.config
-	if cfg.ErrorBurstThreshold == 0 {
-		return
+// limitFigures are the figures of a heuristic that broke hit, a limit: its
+// window, the count and the limit.
+func limitFigures(hit ratelimit.Hit) map[string]any {
+	return map[string]any{
+		figureWindow: hit.Window, figureCount: hit.Count, figureLimit: hit.Limit,
 	}
-
-	if !rq.attack && !rq.ruleBlocked && !rq.wafBlocked {
-		return
-	}
-
-	now := rq.h.now()
-
-	hit, over := rq.h.limiter.CountRefusal(rq.h.clientGroup(rq.client), now,
-		cfg.ErrorBurstThreshold)
-	if !over {
-		return
-	}
-
-	// What the client was sent, or in observe mode would have been.
-	status := rq.out.status
-
-	switch rq.line.WouldAction {
-	case requestlog.ActionRuleBlocked, requestlog.ActionWAFBlocked:
-		status = http.StatusForbidden
-	case requestlog.ActionBanned:
-		status = cfg.BanResponse
-	}
-
-	rq.banForLimit(now, hit, status)
 }
 
 // countedBytes returns the request's bytes, once it has ended, as the

internal/servewaf/bans_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"bufio"
@@ -15,8 +15,8 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -228,6 +228,22 @@ func TestBannedClientIsRefusedBeforeItsCountryIsLookedUp(t *testing.T) {
 	}
 }
 
+func TestRefusalUnderABanNamesItsHeuristicNetblockAndEnd(t *testing.T) {
+	t.Parallel()
+
+	s, clk, _ := startWithClock(t, "", map[string]string{
+		rateLimitPerMinute: "1", banScopeV4Prefix: "24",
+	})
+	expires := requestlog.FormatTime(clk.Now().Add(time.Hour))
+
+	s.get(client, http.StatusOK, requestlog.ActionForward)
+	s.get(client, http.StatusForbidden, requestlog.ActionRateLimited)
+
+	line := s.get(otherClient, http.StatusForbidden, requestlog.ActionBanned)
+	wantHeuristic(t, line, "active_ban",
+		`{"netblock": "`+clientsNet+`", "ban_expires": "`+expires+`"}`)
+}
+
 func TestBanResponseAnswersEveryRefusalButTheSizeLimits(t *testing.T) {
 	t.Parallel()
 
@@ -382,7 +398,7 @@ func (c *clock) advance(d time.Duration) {
 // window.
 func startWithClock(
 	t *testing.T, geojsURL string, env map[string]string,
-) (*sender, *clock, *proxy.Server) {
+) (*sender, *clock, *servewaf.Server) {
 	t.Helper()
 
 	app := startApp(t, func(http.ResponseWriter, *http.Request) {})

internal/servewaf/biased.go

@@ -1,4 +1,4 @@
-package proxy
+package servewaf
 
 import (
 	"sneak.berlin/go/smallwebwaf/internal/config"

internal/servewaf/biased_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"fmt"
@@ -16,8 +16,8 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/bans"
 	"sneak.berlin/go/smallwebwaf/internal/lookup/lookuptest"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // The biased thresholds.
@@ -419,7 +419,7 @@ func TestBanForALoweredLimitGivesThePercentageInItsNotesAndItsAlert(t *testing.T
 // clock.
 func startWithLookups(
 	t *testing.T, env map[string]string,
-) (*sender, *proxy.Server, *alerts.Queue) {
+) (*sender, *servewaf.Server, *alerts.Queue) {
 	t.Helper()
 
 	s, _, server, queue := startWithLookupsAndClock(t, env)
@@ -434,7 +434,7 @@ func startWithLookups(
 // country, and no other address.
 func startWithLookupsAndClock(
 	t *testing.T, env map[string]string,
-) (*sender, *clock, *proxy.Server, *alerts.Queue) {
+) (*sender, *clock, *servewaf.Server, *alerts.Queue) {
 	t.Helper()
 
 	path := filepath.Join(t.TempDir(), "ipinfo_lite.mmdb")
@@ -463,11 +463,11 @@ func (s *sender) uploadFrom(from string) logLine {
 // serveFromDE hands a question about a request from fromDE with method and body
 // straight to server's handler, without the network, and returns once it is
 // answered.
-func serveFromDE(t *testing.T, server *proxy.Server, method string, body io.Reader) {
+func serveFromDE(t *testing.T, server *servewaf.Server, method string, body io.Reader) {
 	t.Helper()
 
 	req := httptest.NewRequestWithContext(t.Context(), method, "/", body)
-	req.Header.Set(proxy.ClientHeader, fromDE)
+	req.Header.Set(servewaf.ClientHeader, fromDE)
 	req.Header.Set(requestIDHeader, "the-id")
 
 	server.Handler.ServeHTTP(httptest.NewRecorder(), req)

internal/servewaf/blocklists.go

@@ -0,0 +1,41 @@
+package servewaf
+
+// The heuristic blocklists. It reads SWWAF_BLOCKLIST_ACTION, and the blocklists
+// through the reputation lists.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// blocklists notes the blocklists that list the client, as noteListed does,
+// and refuses the request when SWWAF_BLOCKLIST_ACTION is deny. Being limit, it
+// lowers the client's limits instead (see limitPercentages), and being log, it
+// does nothing more. Its figure is the blocklists that list the client.
+type blocklists struct{}
+
+func (blocklists) name() string { return "blocklists" }
+
+func (blocklists) check(_ context.Context, rq *request, _ time.Time) *verdict {
+	listedBy := rq.h.lists.ListedBy(rq.client)
+	rq.blocklisted = len(listedBy) > 0
+	rq.noteListed(listedBy, "listed by a blocklist")
+
+	if !rq.refusedByBlocklists(listedBy) {
+		return nil
+	}
+
+	return &verdict{
+		action:  requestlog.ActionDenied,
+		figures: map[string]any{"lists": listedBy},
+	}
+}
+
+// refusedByBlocklists reports whether the heuristic blocklists refuses a
+// client, given listedBy, the blocklists that list it: it does when one lists
+// it and SWWAF_BLOCKLIST_ACTION is deny.
+func (rq *request) refusedByBlocklists(listedBy []string) bool {
+	return len(listedBy) > 0 && rq.h.config.BlocklistAction == deny
+}

internal/servewaf/bytelimits.go

@@ -0,0 +1,43 @@
+package servewaf
+
+// The heuristic byte_limits. It reads SWWAF_BYTES_COUNT, and the byte limits
+// and biased thresholds through the limiter and limitPercentages.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// byteLimits counts the request's bytes, as countedBytes gives them, for the
+// byte limits, once its report has come, and notes the client's byte totals for
+// the log line; its requests stay there as the rate limits counted them. Only
+// an allowed request has them counted, and only one the rate limits counted; in
+// observe mode, not one that enforce mode would have refused. Bytes that take
+// the client over a byte limit, as its limit percentage for the byte limits
+// lowers it, break it, which bans the client; the response was passed on whole.
+// Its figures are the window, the count and the limit.
+type byteLimits struct{}
+
+func (byteLimits) name() string { return "byte_limits" }
+
+func (byteLimits) check(_ context.Context, rq *request, now time.Time) *verdict {
+	if !rq.counted || rq.line.WouldAction != "" {
+		return nil
+	}
+
+	counts, hit, over := rq.h.limiter.CountBytes(rq.h.clientGroup(rq.client), now,
+		rq.countedBytes(), rq.bytesPercent.percent)
+	rq.line.Counts.MinuteBytes = counts.MinuteBytes
+	rq.line.Counts.HourBytes = counts.HourBytes
+	rq.line.Counts.DayBytes = counts.DayBytes
+
+	if !over {
+		return nil
+	}
+
+	rq.banForLimit(now, hit, rq.out.status)
+
+	return &verdict{action: requestlog.ActionBanned, figures: limitFigures(hit)}
+}

internal/servewaf/bytelimits_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"bufio"
@@ -98,6 +98,21 @@ func TestEachByteLimitBansOnceTheResponseHasEnded(t *testing.T) {
 	}
 }
 
+func TestByteLimitBanNamesItsHeuristicWindowCountAndLimit(t *testing.T) {
+	t.Parallel()
+
+	s, _ := startWithAnswers(t, map[string]string{bytesLimitPerMinute: byteLimit})
+
+	line, _ := s.download()
+	wantAfterAnswerHeuristic(t, line, "", "null")
+
+	// Two answers of 70 bytes are over the limit of 99.
+	line, _ = s.download()
+	wantHeuristic(t, line, "", "null")
+	wantAfterAnswerHeuristic(t, line, "byte_limits",
+		`{"window": "minute", "count": 140, "limit": 99}`)
+}
+
 func TestResponseOverAByteLimitByItselfIsPassedOnWhole(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/client.go

@@ -1,4 +1,4 @@
-package proxy
+package servewaf
 
 import (
 	"crypto/rand"

internal/servewaf/coreruleset.go

@@ -1,6 +1,10 @@
-package proxy
+package servewaf
+
+// The heuristic core_rule_set. It reads SWWAF_WAF_MODE, SWWAF_WAF_EXEMPT_PATHS
+// and SWWAF_WAF_ANOMALY_THRESHOLD.
 
 import (
+	"context"
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
@@ -9,18 +13,21 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/waf"
 )
 
-// checkCoreRuleSet inspects the request with the Core Rule Set, unless
+// coreRuleSet inspects the request with the Core Rule Set, unless
 // SWWAF_WAF_MODE is off or SWWAF_WAF_EXEMPT_PATHS exempts its path, as
 // pathExempt decides, and notes the rules it matched and its score in the
 // log line, and the rules in the metrics. A score at or over
 // SWWAF_WAF_ANOMALY_THRESHOLD is a match: it raises the waf_block alert,
-// and in block mode refuses the request, which is an offence its client's
-// history counts, and so returns ActionWAFBlocked. It returns "" for a
-// request it does not refuse.
-func (rq *request) checkCoreRuleSet() string {
+// and in block mode refuses the request with 403, which is an offence its
+// client's history counts. Its figures are the score and the threshold.
+type coreRuleSet struct{}
+
+func (coreRuleSet) name() string { return "core_rule_set" }
+
+func (coreRuleSet) check(_ context.Context, rq *request, _ time.Time) *verdict {
 	cfg := rq.h.config
 	if cfg.WAFMode == config.WAFModeOff || pathExempt(rq.in, cfg.WAFExemptPaths) {
-		return ""
+		return nil
 	}
 
 	start := time.Now()
@@ -40,18 +47,21 @@ func (rq *request) checkCoreRuleSet() string {
 
 	threshold := cfg.WAFAnomalyThreshold
 	if threshold == 0 || result.Score < threshold {
-		return ""
+		return nil
 	}
 
 	rq.alertWAFBlock(result)
 
 	if cfg.WAFMode == config.WAFModeDetect {
-		return ""
+		return nil
 	}
 
 	rq.wafBlocked = true
 
-	return requestlog.ActionWAFBlocked
+	return &verdict{
+		action:  requestlog.ActionWAFBlocked,
+		figures: map[string]any{figureScore: result.Score, "threshold": threshold},
+	}
 }
 
 // alertWAFBlock raises the waf_block alert for the request, which the Core

internal/servewaf/coreruleset_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"io"
@@ -110,6 +110,16 @@ func TestCoreRuleSetRefusesAttacksInBlockModeAndOnlyLogsThemInDetectMode(t *test
 	}
 }
 
+func TestCoreRuleSetRefusalNamesItsHeuristicScoreAndThreshold(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{wafMode: block})
+
+	line := s.request(client, sqlInjection, http.StatusForbidden,
+		requestlog.ActionWAFBlocked)
+	wantHeuristic(t, line, "core_rule_set", `{"score": 5, "threshold": 5}`)
+}
+
 func TestOrdinaryRequestIsInspectedAndPassed(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/countries.go

@@ -0,0 +1,42 @@
+package servewaf
+
+// The heuristic countries. It reads SWWAF_DENIED_COUNTRIES and
+// SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES.
+
+import (
+	"context"
+	"slices"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// countries refuses a request by the client's country as it was looked up. A
+// client without a country, or whose country cannot be found, is refused only
+// by SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES. Its figures are the country and the
+// setting that refused it.
+type countries struct{}
+
+func (countries) name() string { return "countries" }
+
+func (countries) check(_ context.Context, rq *request, _ time.Time) *verdict {
+	denied := rq.h.config.DeniedCountries
+	allowed := rq.h.config.ExclusivelyAllowedCountries
+	country := rq.line.Country
+
+	var setting string
+
+	switch {
+	case slices.Contains(denied, country):
+		setting = "SWWAF_DENIED_COUNTRIES"
+	case len(allowed) > 0 && !slices.Contains(allowed, country):
+		setting = "SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES"
+	default:
+		return nil
+	}
+
+	return &verdict{
+		action:  requestlog.ActionCountryDenied,
+		figures: map[string]any{"country": country, "setting": setting},
+	}
+}

internal/servewaf/countries_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"encoding/json"
@@ -90,6 +90,23 @@ func TestCountryLists(t *testing.T) {
 	}
 }
 
+func TestCountryRefusalNamesItsHeuristicCountryAndSetting(t *testing.T) {
+	t.Parallel()
+
+	geojsURL, _ := startGeoJS(t)
+	s, _, _ := startWithClock(t, geojsURL, map[string]string{
+		lookupTimeout: "1h", deniedCountries: "kp", allowedCountries: "de",
+	})
+
+	line := s.get(fromKP, http.StatusForbidden, requestlog.ActionCountryDenied)
+	wantHeuristic(t, line, "countries",
+		`{"country": "KP", "setting": "SWWAF_DENIED_COUNTRIES"}`)
+
+	line = s.get(unplaced, http.StatusForbidden, requestlog.ActionCountryDenied)
+	wantHeuristic(t, line, "countries",
+		`{"country": "", "setting": "SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES"}`)
+}
+
 func TestCountryRefusalKeepsARequestFromTheApp(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/crowdsec.go

@@ -0,0 +1,49 @@
+package servewaf
+
+// The heuristic crowdsec. It reads SWWAF_CROWDSEC_LAPI_URL, and the decisions
+// through the reputation lists.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/reputation"
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// crowdSec refuses a request when a decision of the CrowdSec decision list on
+// the client is in force at now. It then notes the list, as noteHit does, and
+// bans the client until that decision ends. Its figures are the decision's
+// scenario and when it ends.
+type crowdSec struct{}
+
+func (crowdSec) name() string { return "crowdsec" }
+
+func (crowdSec) check(_ context.Context, rq *request, now time.Time) *verdict {
+	decision, listed := rq.crowdSecDecisionInForce(now)
+	if !listed {
+		return nil
+	}
+
+	rq.noteHit(bans.ReputationHit{Source: rq.h.config.CrowdSecDecisionsURL},
+		"listed by the CrowdSec decision list")
+	rq.banForCrowdSec(now, decision)
+
+	return &verdict{
+		action: requestlog.ActionBanned,
+		figures: map[string]any{
+			"scenario": decision.Scenario,
+			"expires":  requestlog.FormatTime(decision.Expires),
+		},
+	}
+}
+
+// crowdSecDecisionInForce returns the decision of the CrowdSec decision list on
+// the client that is in force at now, and reports whether there is one, which
+// the heuristic crowdsec refuses the request for.
+func (rq *request) crowdSecDecisionInForce(
+	now time.Time,
+) (reputation.Decision, bool) {
+	return rq.h.lists.CrowdSecDecision(rq.client, now)
+}

internal/servewaf/crowdsec_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
@@ -9,9 +9,9 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // The CrowdSec settings, and the tests' engine, which is never asked: each
@@ -95,6 +95,21 @@ func TestClientTheCrowdSecDecisionListListsIsBannedUntilTheDecisionEnds(t *testi
 		float64(fetched.Unix()))
 }
 
+func TestCrowdSecBanNamesItsHeuristicScenarioAndEnd(t *testing.T) {
+	t.Parallel()
+
+	s, clk, server, _ := startWithAlerts(t, map[string]string{
+		crowdSecURL: lapi, crowdSecKey: bouncerKey,
+	})
+	loadDecisions(t, server, clk.Now(), `[{"duration": "4h0m0s", `+
+		`"scenario": "crowdsecurity/ssh-bf", "scope": "Ip", "type": "ban", `+
+		`"value": "`+client+`"}]`)
+
+	line := s.get(client, http.StatusForbidden, requestlog.ActionBanned)
+	wantHeuristic(t, line, "crowdsec", `{"scenario": "crowdsecurity/ssh-bf", `+
+		`"expires": "`+requestlog.FormatTime(clk.Now().Add(4*time.Hour))+`"}`)
+}
+
 func TestEndedCrowdSecDecisionNoLongerBansThoughTheCopyStillHoldsIt(t *testing.T) {
 	t.Parallel()
 
@@ -168,7 +183,7 @@ func TestObserveModeForwardsAClientTheCrowdSecDecisionListListsAndAlertsTheBan(
 // decisionsURL, answer, the engine's answer, fetched at fetched, as
 // reputation.json would at start.
 func loadDecisions(
-	t *testing.T, server *proxy.Server, fetched time.Time, answer string,
+	t *testing.T, server *servewaf.Server, fetched time.Time, answer string,
 ) {
 	t.Helper()
 

internal/servewaf/denynets.go

@@ -0,0 +1,29 @@
+package servewaf
+
+// The heuristic deny_nets. It reads SWWAF_DENY_NETS.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// denyNets refuses a client in SWWAF_DENY_NETS. Its figure is the netblock of
+// the setting the client is in.
+type denyNets struct{}
+
+func (denyNets) name() string { return "deny_nets" }
+
+func (denyNets) check(_ context.Context, rq *request, _ time.Time) *verdict {
+	for _, netblock := range rq.h.config.DenyNets {
+		if netblock.Contains(rq.client) {
+			return &verdict{
+				action:  requestlog.ActionDenied,
+				figures: map[string]any{figureNetblock: netblock.String()},
+			}
+		}
+	}
+
+	return nil
+}

internal/servewaf/dnsbl.go

@@ -0,0 +1,36 @@
+package servewaf
+
+// The heuristic dnsbl. It reads SWWAF_REPUTATION_ACTION, and the DNSBL zones'
+// verdicts through the DNSBL checker.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// dnsbl notes the DNSBL zones whose verdict lists the client, as noteListed
+// does, and refuses the request when SWWAF_REPUTATION_ACTION is deny. Being
+// limit, it lowers the client's limits instead (see limitPercentages), and
+// being log, it does nothing more. A zone without a verdict on the client is
+// asked about it in the background, and the request does not wait for the
+// answer. Its figure is the zones that list the client, their keys masked.
+type dnsbl struct{}
+
+func (dnsbl) name() string { return "dnsbl" }
+
+func (dnsbl) check(ctx context.Context, rq *request, _ time.Time) *verdict {
+	listedBy := rq.h.dnsbl.ListedBy(ctx, rq.client)
+	rq.dnsblListed = len(listedBy) > 0
+	rq.noteListed(listedBy, "listed by a DNSBL zone")
+
+	if !rq.dnsblListed || rq.h.config.ReputationAction != deny {
+		return nil
+	}
+
+	return &verdict{
+		action:  requestlog.ActionDenied,
+		figures: map[string]any{"zones": listedBy},
+	}
+}

internal/servewaf/headerlimits.go

@@ -0,0 +1,71 @@
+package servewaf
+
+// The heuristic header_limits. It reads no setting: its limits are fixed.
+
+import (
+	"context"
+	"strings"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// The header limits: the most cookies and header fields a request may have
+// when the checks reach the Core Rule Set. Real clients never reach them.
+const (
+	maxCookies      = 50
+	maxHeaderFields = 100
+)
+
+// headerLimits refuses a request over the header limits, with 431. Its figures
+// are the request's header fields and cookies, and the limit of each.
+type headerLimits struct{}
+
+func (headerLimits) name() string { return "header_limits" }
+
+func (headerLimits) check(_ context.Context, rq *request, _ time.Time) *verdict {
+	fields, cookies := rq.headerCounts()
+	if !overHeaderLimits(fields, cookies) {
+		return nil
+	}
+
+	return &verdict{
+		action: requestlog.ActionTooLarge,
+		figures: map[string]any{
+			"fields": fields, "fields_limit": maxHeaderFields,
+			"cookies": cookies, "cookies_limit": maxCookies,
+		},
+	}
+}
+
+// overHeaderLimits reports whether a request with these counts of header fields
+// and cookies, as headerCounts counts them, is over the header limits: it has
+// more than maxHeaderFields fields or more than maxCookies cookies.
+func overHeaderLimits(fields, cookies int) bool {
+	return fields > maxHeaderFields || cookies > maxCookies
+}
+
+// headerCounts returns the request's header fields, each value of a header sent
+// twice being one, and its cookies, each part of a Cookie header between
+// semicolons being one unless it is empty or only spaces and tabs. The Core
+// Rule Set runs each of its rules on each cookie, so that thousands of small
+// cookies keep it busy for over a second. It trims only spaces and control
+// characters, of which a header value can hold only tabs, so a part of Unicode
+// spaces is a cookie to it.
+func (rq *request) headerCounts() (int, int) {
+	fields, cookies := 0, 0
+
+	for _, values := range rq.in.Header {
+		fields += len(values)
+	}
+
+	for _, value := range rq.in.Header.Values("Cookie") {
+		for part := range strings.SplitSeq(value, ";") {
+			if strings.Trim(part, " \t") != "" {
+				cookies++
+			}
+		}
+	}
+
+	return fields, cookies
+}

internal/servewaf/health_test.go

@@ -1,11 +1,11 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
 	"testing"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 func TestHealthEndpointCountsTowardNoLimit(t *testing.T) {
@@ -21,7 +21,7 @@ func TestHealthEndpointCountsTowardNoLimit(t *testing.T) {
 	)
 
 	for range healthChecks {
-		got := s.adminRequest("", http.MethodGet, proxy.HealthPath, "", http.StatusOK)
+		got := s.adminRequest("", http.MethodGet, servewaf.HealthPath, "", http.StatusOK)
 
 		if string(got.body) != "ok\n" || got.header.Get("Content-Type") != contentType {
 			t.Errorf("health endpoint answered %q with Content-Type %q, want ok "+

internal/servewaf/heuristics.go

@@ -0,0 +1,133 @@
+package servewaf
+
+import (
+	"context"
+	"time"
+)
+
+// To add a heuristic, write one file with a type that implements heuristic,
+// and add one line for it to one of the lists below. Its settings go in
+// config.Config, and the comment at the top of its file names them.
+
+// heuristic is one of the checks that decide what servewaf does with a request.
+type heuristic interface {
+	// name is the heuristic's name, which the log line gives.
+	name() string
+	// check looks at the request at now, and returns nil to let it through.
+	// ctx is the request's own context.
+	check(ctx context.Context, rq *request, now time.Time) *verdict
+}
+
+// verdict is a heuristic refusing a request, or banning its client: the action
+// the log line names, one of requestlog's Action constants, and the figures the
+// heuristic acted on, by name, such as the count and the limit.
+type verdict struct {
+	action  string
+	figures map[string]any
+}
+
+// The names of the figures that more than one heuristic gives.
+const (
+	figureWindow   = "window"
+	figureCount    = "count"
+	figureLimit    = "limit"
+	figureScore    = "score"
+	figureNetblock = "netblock"
+)
+
+// The lists of heuristics, each in the order its heuristics run. A client in
+// SWWAF_ALLOW_NETS skips them all.
+
+// beforeLookup are the heuristics that run before the client's AS number and
+// country are looked up, so that a client they refuse is not looked up.
+func beforeLookup() []heuristic {
+	return []heuristic{
+		denyNets{},
+		activeBan{},
+	}
+}
+
+// afterLookup are the heuristics that run once the lookup has been made.
+func afterLookup() []heuristic {
+	return []heuristic{
+		countries{},
+		blocklists{},
+		crowdSec{},
+		dnsbl{},
+		abuseIPDB{},
+		rateLimits{},
+		trapPaths{},
+		ruleFiles{},
+		headerLimits{},
+		coreRuleSet{},
+	}
+}
+
+// afterAnswer are the heuristics that run on a request once servewaf has
+// answered it, before its decision line is written. They ban the client, and do
+// not change what the request got: their verdict's action is not used.
+func afterAnswer() []heuristic {
+	return []heuristic{
+		refusalLimit{},
+	}
+}
+
+// onReport are the heuristics that run on an allowed request when rproxy's
+// report of it comes, before its report line is written. Like afterAnswer, they
+// only ban.
+func onReport() []heuristic {
+	return []heuristic{
+		byteLimits{},
+	}
+}
+
+// runAfterAnswer runs the heuristics of afterAnswer on the request, at the time
+// it is called.
+func (rq *request) runAfterAnswer(ctx context.Context) {
+	rq.runBanningHeuristics(ctx, afterAnswer())
+}
+
+// runHeuristics runs list, beforeLookup or afterLookup, on the request at now,
+// and returns the first verdict, or nil when none gives one. The log line's
+// heuristic and heuristic_figures name the heuristic that gave it, and give its
+// figures. ctx is the request's own context.
+func (rq *request) runHeuristics(
+	ctx context.Context, list []heuristic, now time.Time,
+) *verdict {
+	name, v := rq.firstVerdict(ctx, list, now)
+	if v != nil {
+		rq.line.Heuristic = name
+		rq.line.HeuristicFigures = v.figures
+	}
+
+	return v
+}
+
+// runBanningHeuristics runs list, afterAnswer or onReport, on the request at
+// the time it is called. The log line's after_answer_heuristic and
+// after_answer_heuristic_figures name the heuristic that gave a verdict, and
+// give its figures, so that heuristic and heuristic_figures still name the one
+// that refused the request. ctx is the request's own context.
+func (rq *request) runBanningHeuristics(ctx context.Context, list []heuristic) {
+	name, v := rq.firstVerdict(ctx, list, rq.h.now())
+	if v != nil {
+		rq.line.AfterAnswerHeuristic = name
+		rq.line.AfterAnswerHeuristicFigures = v.figures
+	}
+}
+
+// firstVerdict runs list on the request at now, in order, until a heuristic
+// gives a verdict, and returns that heuristic's name and its verdict, or "" and
+// nil when none gives one. ctx is the request's own context.
+func (rq *request) firstVerdict(
+	ctx context.Context, list []heuristic, now time.Time,
+) (string, *verdict) {
+	for _, each := range list {
+		v := each.check(ctx, rq, now)
+		if v != nil {
+			return each.name(), v
+		}
+	}
+
+	return "", nil
+}

internal/servewaf/history_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"io"
@@ -8,9 +8,9 @@ import (
 	"testing"
 	"time"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 func TestHistoryKeepsEachRequestOfTheClient(t *testing.T) {
@@ -100,8 +100,8 @@ func TestOwnEndpointsAreNotInTheHistory(t *testing.T) {
 
 	s, _, server := startWithClock(t, "", map[string]string{metricsToken: token})
 
-	s.adminRequest("", http.MethodGet, proxy.HealthPath, "", http.StatusOK)
-	s.adminRequest("", http.MethodGet, proxy.MetricsPath, "", http.StatusUnauthorized)
+	s.adminRequest("", http.MethodGet, servewaf.HealthPath, "", http.StatusOK)
+	s.adminRequest("", http.MethodGet, servewaf.MetricsPath, "", http.StatusUnauthorized)
 	s.scrape()
 
 	if clients := server.Limiter.Snapshot(); len(clients) != 0 {
@@ -126,7 +126,7 @@ func TestPathUnderTheOwnPrefixIsNeitherForwardedNorRefused(t *testing.T) {
 }
 
 // historyOf returns the history of the client at addr.
-func historyOf(t *testing.T, server *proxy.Server, addr string) ratelimit.History {
+func historyOf(t *testing.T, server *servewaf.Server, addr string) ratelimit.History {
 	t.Helper()
 
 	client := netip.MustParsePrefix(addr + "/32")

internal/servewaf/lookup.go

@@ -1,4 +1,4 @@
-package proxy
+package servewaf
 
 import (
 	"context"

internal/servewaf/lookup_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
@@ -379,7 +379,7 @@ func TestRequestWaitsAsLongAsTheLookupTimeoutSays(t *testing.T) {
 	// clock of the test's own: the wait lasts exactly as long as it should,
 	// however slowly the test process runs. Nothing in it may wait on the
 	// network, which would keep that clock from moving on: the request is
-	// handed to the proxy's handler, and GeoJS is one that never answers.
+	// handed to servewaf's handler, and GeoJS is one that never answers.
 	synctest.Test(t, func(t *testing.T) {
 		// Not the default. The exclusive list needs the answer, and the app
 		// is never reached.

internal/servewaf/metrics_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"io"
@@ -12,8 +12,8 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
 	"sneak.berlin/go/smallwebwaf/internal/lookup"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -32,7 +32,7 @@ func TestMetricsAreOffWhileTheTokenIsUnset(t *testing.T) {
 
 	// An empty token does not match the unset one either.
 	for _, authorization := range []string{bearer, "Bearer ", ""} {
-		s.adminRequest(authorization, http.MethodGet, proxy.MetricsPath, "",
+		s.adminRequest(authorization, http.MethodGet, servewaf.MetricsPath, "",
 			http.StatusNotFound)
 	}
 }
@@ -46,18 +46,18 @@ func TestMetricsNeedTheTokenAndOtherPathsAreNotFound(t *testing.T) {
 		method, path, authorization string
 		status                      int
 	}{
-		{http.MethodGet, proxy.MetricsPath, "", http.StatusUnauthorized},
+		{http.MethodGet, servewaf.MetricsPath, "", http.StatusUnauthorized},
 		{
-			http.MethodGet, proxy.MetricsPath, "Bearer " + strings.ToUpper(token),
+			http.MethodGet, servewaf.MetricsPath, "Bearer " + strings.ToUpper(token),
 			http.StatusUnauthorized,
 		},
-		{http.MethodGet, proxy.MetricsPath, "Basic " + token, http.StatusUnauthorized},
-		{http.MethodGet, proxy.MetricsPath, bearer, http.StatusOK},
-		{http.MethodGet, proxy.MetricsPath, "bearer " + token, http.StatusOK},
-		{http.MethodPost, proxy.MetricsPath, bearer, http.StatusNotFound},
-		{http.MethodGet, proxy.MetricsPath + "/", bearer, http.StatusNotFound},
+		{http.MethodGet, servewaf.MetricsPath, "Basic " + token, http.StatusUnauthorized},
+		{http.MethodGet, servewaf.MetricsPath, bearer, http.StatusOK},
+		{http.MethodGet, servewaf.MetricsPath, "bearer " + token, http.StatusOK},
+		{http.MethodPost, servewaf.MetricsPath, bearer, http.StatusNotFound},
+		{http.MethodGet, servewaf.MetricsPath + "/", bearer, http.StatusNotFound},
 		{http.MethodGet, "/_smallwebwaf/bans", bearer, http.StatusNotFound},
-		{http.MethodPost, proxy.HealthPath, "", http.StatusNotFound},
+		{http.MethodPost, servewaf.HealthPath, "", http.StatusNotFound},
 	} {
 		got := s.adminRequest(tc.authorization, tc.method, tc.path, "", tc.status)
 
@@ -180,7 +180,7 @@ func TestMetricsCountTheBansAnAdminMakes(t *testing.T) {
 	wantMetric(t, s.scrape(), admins, 1)
 
 	// And a ban made through the endpoint.
-	s.admin(http.MethodPost, proxy.BansPath, banOtherClient, http.StatusOK)
+	s.admin(http.MethodPost, servewaf.BansPath, banOtherClient, http.StatusOK)
 	wantMetric(t, s.scrape(), admins, 2)
 }
 
@@ -365,7 +365,7 @@ func keptAnswer(addr, country string) lookup.Answer {
 func scrape(t *testing.T, addr string) string {
 	t.Helper()
 
-	req := newRequest(t, http.MethodGet, addr, proxy.MetricsPath, http.NoBody)
+	req := newRequest(t, http.MethodGet, addr, servewaf.MetricsPath, http.NoBody)
 	req.Header.Set("Authorization", bearer)
 
 	got := do(t, req)
@@ -380,7 +380,7 @@ func scrape(t *testing.T, addr string) string {
 func (s *sender) scrape() string {
 	s.t.Helper()
 
-	return string(s.adminRequest(bearer, http.MethodGet, proxy.MetricsPath, "",
+	return string(s.adminRequest(bearer, http.MethodGet, servewaf.MetricsPath, "",
 		http.StatusOK).body)
 }
 

internal/servewaf/observe_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
@@ -14,6 +14,18 @@ import (
 // observe is the value of SWWAF_MODE for observe mode.
 const observe = "observe"
 
+func TestObserveModeNamesTheHeuristicThatWouldHaveRefused(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{
+		mode: observe, denyNets: client,
+	})
+
+	line := s.get(client, http.StatusOK, requestlog.ActionForward)
+	wantWouldAction(t, line, requestlog.ActionDenied)
+	wantHeuristic(t, line, "deny_nets", `{"netblock": "`+client+`/32"}`)
+}
+
 func TestObserveModeForwardsWhatEnforceModeRefuses(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/proxy.go

@@ -1,10 +1,7 @@
-// Package proxy is servewaf's server. It runs the checks on the request each of
-// rproxy's questions carries, and answers rproxy what to do with that request. It
-// takes rproxy's report once the visitor's answer has ended, which counts the
-// request's bytes and writes its last log line. It answers servewaf's own
-// endpoints: the health check, the metrics, the bans and the clients. It passes
-// nothing to an app: internal/rproxy does that.
-package proxy
+// Package servewaf is the server the servewaf command runs. It answers rproxy's
+// questions, takes rproxy's reports and answers its own endpoints, and writes a
+// log line for each.
+package servewaf
 
 import (
 	"io"
@@ -46,7 +43,7 @@ const BansPath = "/_smallwebwaf/bans"
 // client's address after it, with SWWAF_ADMIN_TOKEN.
 const ClientsPath = "/_smallwebwaf/clients/"
 
-// Params are what NewServeWAF needs.
+// Params are what New needs.
 type Params struct {
 	Config *config.Config
 	// RequestLog receives two JSON lines per question, one at its decision and

internal/servewaf/proxy_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"bufio"
@@ -18,10 +18,10 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/lookup"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rproxy"
 	"sneak.berlin/go/smallwebwaf/internal/rules"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -300,7 +300,7 @@ func startProxyWithGeoJS(
 func startProxyWithClock(
 	t *testing.T, appURL, geojsURL string, now func() time.Time,
 	env map[string]string,
-) (string, *output, *proxy.Server) {
+) (string, *output, *servewaf.Server) {
 	t.Helper()
 
 	addr, out, server, _ := startProxyWithAlerts(t, appURL, geojsURL, now, env)
@@ -313,7 +313,7 @@ func startProxyWithClock(
 func startProxyWithAlerts(
 	t *testing.T, appURL, geojsURL string, now func() time.Time,
 	env map[string]string,
-) (string, *output, *proxy.Server, *alerts.Queue) {
+) (string, *output, *servewaf.Server, *alerts.Queue) {
 	t.Helper()
 
 	server, out, alertQueue := newServeWAF(t, geojsURL, now, env)
@@ -324,7 +324,7 @@ func startProxyWithAlerts(
 
 // serve serves server on a port of its own until the test ends, and sets its
 // Addr to where it listens.
-func serve(t *testing.T, server *proxy.Server) {
+func serve(t *testing.T, server *servewaf.Server) {
 	t.Helper()
 
 	listener, err := (&net.ListenConfig{}).Listen(t.Context(), "tcp", localhost+":0")
@@ -401,17 +401,17 @@ func startRProxy(
 // inspected by it.
 func newServeWAF(
 	t *testing.T, geojsURL string, now func() time.Time, env map[string]string,
-) (*proxy.Server, *output, *alerts.Queue) {
+) (*servewaf.Server, *output, *alerts.Queue) {
 	t.Helper()
 
-	return newServeWAFWith(t, proxy.NewServeWAF, geojsURL, now, env)
+	return newServeWAFWith(t, servewaf.New, geojsURL, now, env)
 }
 
 // newServeWAFWith is newServeWAF for the server build makes.
 func newServeWAFWith(
-	t *testing.T, build func(proxy.Params) *proxy.Server,
+	t *testing.T, build func(servewaf.Params) *servewaf.Server,
 	geojsURL string, now func() time.Time, env map[string]string,
-) (*proxy.Server, *output, *alerts.Queue) {
+) (*servewaf.Server, *output, *alerts.Queue) {
 	t.Helper()
 
 	settings := map[string]string{
@@ -463,7 +463,7 @@ func newServeWAFWith(
 		}
 	}
 
-	server := build(proxy.Params{
+	server := build(servewaf.Params{
 		Config:       cfg,
 		RequestLog:   out,
 		ProcessLog:   processLog,

internal/servewaf/ratelimits.go

@@ -0,0 +1,65 @@
+package servewaf
+
+// The heuristic rate_limits. It reads SWWAF_RATE_LIMIT_EXEMPT_NETS,
+// SWWAF_RATE_LIMIT_EXEMPT_PATHS and SWWAF_BAN_RESPONSE, and the rate limits and
+// biased thresholds through the limiter and limitPercentages.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// rateLimits counts the request for the rate limits, unless
+// countedByRateLimits exempts it, by the client's limit percentages, which it
+// notes for the log line with the client's counts. A request that takes the
+// client over a rate limit, as its limit percentage lowers it, breaks it: it is
+// refused, and bans the client. A request exempt from the rate limits is exempt
+// from the byte limits too. Its figures are the window, the count and the
+// limit.
+type rateLimits struct{}
+
+func (rateLimits) name() string { return "rate_limits" }
+
+func (rateLimits) check(_ context.Context, rq *request, now time.Time) *verdict {
+	rq.counted = rq.countedByRateLimits()
+	if !rq.counted {
+		return nil
+	}
+
+	rq.limitPercent, rq.bytesPercent = rq.limitPercentages()
+	rq.line.LimitPercent, rq.line.LimitPercentSetting = rq.limitPercent.logged()
+	rq.line.BytesPercent, rq.line.BytesPercentSetting = rq.bytesPercent.logged()
+
+	counts, hit, over := rq.h.limiter.Count(rq.h.clientGroup(rq.client), now,
+		rq.limitPercent.percent)
+	rq.line.Counts = counts
+
+	if !over {
+		return nil
+	}
+
+	rq.banForLimit(now, hit, rq.h.config.BanResponse)
+
+	return &verdict{action: requestlog.ActionRateLimited, figures: limitFigures(hit)}
+}
+
+// overAWholeRateLimit reports whether the heuristic rate_limits will refuse the
+// request at now, whatever its client's limit percentages: the rate limits
+// count it, and one more request from its client takes it over a whole rate
+// limit. It counts nothing.
+func (rq *request) overAWholeRateLimit(now time.Time) bool {
+	return rq.countedByRateLimits() &&
+		rq.h.limiter.OverARateLimit(rq.h.clientGroup(rq.client), now)
+}
+
+// countedByRateLimits reports whether the rate limits count the request: its
+// client is not in SWWAF_RATE_LIMIT_EXEMPT_NETS, and its path is not exempt
+// under SWWAF_RATE_LIMIT_EXEMPT_PATHS.
+func (rq *request) countedByRateLimits() bool {
+	cfg := rq.h.config
+
+	return !isInside(rq.client, cfg.RateLimitExemptNets) &&
+		!pathExempt(rq.in, cfg.RateLimitExemptPaths)
+}

internal/servewaf/ratelimits_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
@@ -72,6 +72,17 @@ func TestRateLimitRefusesBeforeTheApp(t *testing.T) {
 	}
 }
 
+func TestRateLimitRefusalNamesItsHeuristicWindowCountAndLimit(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{rateLimitPerMinute: "1"})
+
+	s.get(client, http.StatusOK, requestlog.ActionForward)
+
+	line := s.get(client, http.StatusForbidden, requestlog.ActionRateLimited)
+	wantHeuristic(t, line, "rate_limits", `{"window": "minute", "count": 2, "limit": 1}`)
+}
+
 func TestIPv6GroupPrefixSetsTheClientTheLimitsCount(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/refusallimit.go

@@ -0,0 +1,54 @@
+package servewaf
+
+// The heuristic refusal_limit. It reads SWWAF_ERROR_BURST_THRESHOLD and
+// SWWAF_BAN_RESPONSE.
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// refusalLimit counts the request once it has been answered, if servewaf
+// refused it after a rule file match, a trap path or a Core Rule Set match, and
+// in observe mode if enforce mode would have: more than
+// SWWAF_ERROR_BURST_THRESHOLD such refusals of the client within a minute break
+// a limit, which bans the client. A client in SWWAF_ALLOW_NETS, which the
+// heuristics skip, is not counted, and nothing is while the threshold is off.
+// Its figures are the window, the count and the limit.
+type refusalLimit struct{}
+
+func (refusalLimit) name() string { return "refusal_limit" }
+
+func (refusalLimit) check(_ context.Context, rq *request, now time.Time) *verdict {
+	cfg := rq.h.config
+	if cfg.ErrorBurstThreshold == 0 {
+		return nil
+	}
+
+	if !rq.attack && !rq.ruleBlocked && !rq.wafBlocked {
+		return nil
+	}
+
+	hit, over := rq.h.limiter.CountRefusal(rq.h.clientGroup(rq.client), now,
+		cfg.ErrorBurstThreshold)
+	if !over {
+		return nil
+	}
+
+	// What the client was sent, or in observe mode would have been.
+	status := rq.out.status
+
+	switch rq.line.WouldAction {
+	case requestlog.ActionRuleBlocked, requestlog.ActionWAFBlocked:
+		status = http.StatusForbidden
+	case requestlog.ActionBanned:
+		status = cfg.BanResponse
+	}
+
+	rq.banForLimit(now, hit, status)
+
+	return &verdict{action: requestlog.ActionBanned, figures: limitFigures(hit)}
+}

internal/servewaf/refusallimit_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"maps"
@@ -10,9 +10,9 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const errorBurstThreshold = "SWWAF_ERROR_BURST_THRESHOLD"
@@ -51,7 +51,7 @@ func (r refused) send(s *sender, from string) logLine {
 // SWWAF_ERROR_BURST_THRESHOLD at threshold, and the settings in env.
 func startForErrorBurst(
 	t *testing.T, threshold string, env map[string]string,
-) (*sender, *clock, *proxy.Server) {
+) (*sender, *clock, *servewaf.Server) {
 	t.Helper()
 
 	settings := map[string]string{
@@ -106,6 +106,25 @@ func TestErrorBurstBreaksAtOneOverTheThreshold(t *testing.T) {
 	}
 }
 
+func TestRefusalLimitBanNamesItsHeuristicWindowCountAndLimit(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startForErrorBurst(t, "1", nil)
+
+	const ruleFigures = `{"rule_id": "blocked", "rule_action": "block"}`
+
+	line := blockRule.send(s, client)
+	wantHeuristic(t, line, "rule_files", ruleFigures)
+	wantAfterAnswerHeuristic(t, line, "", "null")
+
+	// The second refusal is the request refusal_limit bans for, and the line
+	// names both.
+	line = blockRule.send(s, client)
+	wantHeuristic(t, line, "rule_files", ruleFigures)
+	wantAfterAnswerHeuristic(t, line, "refusal_limit",
+		`{"window": "minute", "count": 2, "limit": 1}`)
+}
+
 func TestErrorBurstBanNotesHistoryAndMetrics(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/reputation.go

@@ -0,0 +1,48 @@
+package servewaf
+
+// What the reputation heuristics share: blocklists, crowdsec, dnsbl and
+// abuseipdb.
+
+import (
+	"sneak.berlin/go/smallwebwaf/internal/alerts"
+	"sneak.berlin/go/smallwebwaf/internal/bans"
+)
+
+// deny is the SWWAF_BLOCKLIST_ACTION and the SWWAF_REPUTATION_ACTION that
+// refuses the requests of a client a source lists.
+const deny = "deny"
+
+// noteListed notes each of sources, the URLs of the blocklists or the
+// DNSBL zones, their keys masked, that list the client, as noteHit does,
+// with reason.
+func (rq *request) noteListed(sources []string, reason string) {
+	for _, source := range sources {
+		rq.noteHit(bans.ReputationHit{Source: source}, reason)
+	}
+}
+
+// noteHit adds hit's source, which lists the client, to the log line's
+// reputation, and hit to the notes of a ban the request makes, counts the
+// source in the metrics, and raises a reputation_hit alert with reason,
+// whose detail gives hit's source and score.
+func (rq *request) noteHit(hit bans.ReputationHit, reason string) {
+	detail := map[string]any{"source": hit.Source}
+	if hit.Score != nil {
+		detail["score"] = *hit.Score
+	}
+
+	rq.line.Reputation = append(rq.line.Reputation, hit.Source)
+	rq.reputation = append(rq.reputation, hit)
+	rq.h.metrics.ReputationHit(hit.Source)
+	rq.h.alerts.Raise(alerts.Alert{
+		Event:    alerts.EventReputationHit,
+		Host:     rq.site,
+		Client:   rq.client,
+		Netblock: rq.h.clientGroup(rq.client),
+		ASN:      rq.line.ASN,
+		ASName:   rq.line.ASName,
+		Country:  rq.line.Country,
+		Reason:   reason,
+		Detail:   detail,
+	})
+}

internal/servewaf/reputation_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"fmt"
@@ -15,10 +15,10 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // The reputation settings.
@@ -118,6 +118,56 @@ func TestEachBlocklistActionForAListedAddressAndAListedNetblock(t *testing.T) {
 	}
 }
 
+func TestReputationRefusalNamesItsHeuristicAndWhatListedTheClient(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range []struct {
+		heuristic string
+		env       map[string]string
+		load      func(*testing.T, *servewaf.Server)
+		figures   string
+	}{
+		{
+			"blocklists",
+			map[string]string{blocklistURLs: dropURL, blocklistAction: actionDeny},
+			func(t *testing.T, server *servewaf.Server) {
+				t.Helper()
+				loadLists(t, server, map[string][]string{dropURL: {client}})
+			},
+			`{"lists": ["` + dropURL + `"]}`,
+		},
+		{
+			"dnsbl",
+			map[string]string{
+				dnsblZones: dnsblZone, dnsblResolver: noResolver,
+				reputationAction: actionDeny,
+			},
+			func(_ *testing.T, server *servewaf.Server) {
+				loadVerdicts(server, map[string][]string{client: {dnsblZone}})
+			},
+			`{"zones": ["` + dnsblZone + `"]}`,
+		},
+		{
+			"abuseipdb",
+			map[string]string{abuseIPDBKey: accountKey, reputationAction: actionDeny},
+			func(_ *testing.T, server *servewaf.Server) {
+				loadScores(server, map[string]int64{client: 80})
+			},
+			`{"score": 80, "min_score": 75}`,
+		},
+	} {
+		t.Run(tc.heuristic, func(t *testing.T) {
+			t.Parallel()
+
+			s, server, _ := startWithLookups(t, tc.env)
+			tc.load(t, server)
+
+			line := s.get(client, http.StatusForbidden, requestlog.ActionDenied)
+			wantHeuristic(t, line, tc.heuristic, tc.figures)
+		})
+	}
+}
+
 func TestBlocklistsComeAfterTheCountryListsAndSkipAllowNets(t *testing.T) {
 	t.Parallel()
 
@@ -617,7 +667,7 @@ const (
 // AbuseIPDB.
 const abuseipdb = reputation.AbuseIPDBSource
 
-// abuseIPDBURL is where newProxy has clients checked with AbuseIPDB: at
+// abuseIPDBURL is where newServeWAF has clients checked with AbuseIPDB: at
 // abuseIPDBStandIn, which TestMain registers with Go's default transport,
 // through which AbuseIPDB is asked.
 const abuseIPDBURL = "abuseipdb://stand-in/api/v2/check"
@@ -975,7 +1025,7 @@ func verdictsFetched() time.Time {
 // verdictsFetched, as reputation.json would at start: one that lists the
 // client from each zone listedBy gives for it, and one that does not from
 // each other zone.
-func loadVerdicts(server *proxy.Server, listedBy map[string][]string) {
+func loadVerdicts(server *servewaf.Server, listedBy map[string][]string) {
 	verdicts := make([]reputation.Verdict, 0, len(listedBy)*len(server.DNSBL.Zones()))
 
 	for client, zones := range listedBy {
@@ -993,7 +1043,7 @@ func loadVerdicts(server *proxy.Server, listedBy map[string][]string) {
 // loadScores puts into server's AbuseIPDB the score scores gives each
 // client, an IPv4 address, fetched at verdictsFetched, as reputation.json
 // would at start.
-func loadScores(server *proxy.Server, scores map[string]int64) {
+func loadScores(server *servewaf.Server, scores map[string]int64) {
 	kept := make([]reputation.Score, 0, len(scores))
 	for client, score := range scores {
 		kept = append(kept, reputation.Score{
@@ -1007,7 +1057,7 @@ func loadScores(server *proxy.Server, scores map[string]int64) {
 
 // wantAbuseIPDBChecks checks how many clients server has checked with
 // AbuseIPDB.
-func wantAbuseIPDBChecks(t *testing.T, server *proxy.Server, want int) {
+func wantAbuseIPDBChecks(t *testing.T, server *servewaf.Server, want int) {
 	t.Helper()
 
 	if got := server.AbuseIPDB.Checked(); got != want {
@@ -1017,7 +1067,7 @@ func wantAbuseIPDBChecks(t *testing.T, server *proxy.Server, want int) {
 
 // loadLists puts copies of lists into server's lists, by URL, each with
 // its lines, fetched at listsFetched, as reputation.json would at start.
-func loadLists(t *testing.T, server *proxy.Server, copies map[string][]string) {
+func loadLists(t *testing.T, server *servewaf.Server, copies map[string][]string) {
 	t.Helper()
 
 	lists := make([]reputation.List, 0, len(copies))

internal/servewaf/request.go

@@ -1,4 +1,4 @@
-package proxy
+package servewaf
 
 import (
 	"context"
@@ -160,16 +160,20 @@ func requestHeaders(r *http.Request, names []string) map[string]string {
 }
 
 // check is the one place where a request can be refused. It returns nil to let
-// the request through. The checks of checkClient decide: a request they refuse
-// is answered with SWWAF_BAN_RESPONSE, 403 for a block rule or the Core Rule Set,
-// or 431 for the header limits. In observe mode nothing is refused, and the log
-// line names what enforce mode would have done. ctx is the request's own context.
+// the request through. The heuristics of checkClient decide: a request they
+// refuse is answered with SWWAF_BAN_RESPONSE, 403 for a block rule or the Core
+// Rule Set, or 431 for the header limits. In observe mode nothing is refused,
+// and the log line names what enforce mode would have done. ctx is the
+// request's own context.
 func (rq *request) check(ctx context.Context) *refusal {
-	action := rq.checkClient(ctx)
+	v := rq.checkClient(ctx)
+	if v == nil {
+		return nil
+	}
+
+	action := v.action
 
 	switch {
-	case action == "":
-		return nil
 	case rq.h.config.Observe:
 		rq.line.WouldAction = action
 
@@ -183,35 +187,21 @@ func (rq *request) check(ctx context.Context) *refusal {
 	}
 }
 
-// checkClient runs the checks on the request's client, and returns the
-// action of the first that refuses the request, or "" when none does. A
-// client in SWWAF_ALLOW_NETS skips them, and is not looked up. For any
-// other client, SWWAF_DENY_NETS comes first, then a ban on its netblock,
-// so that a client either refuses is not looked up, then the lookup of
-// its AS number and country, then the country lists, then the blocklists,
-// then the CrowdSec decision list, which bans the client it lists, then
-// the DNSBL zones' verdicts, and then AbuseIPDB's score; a request any of
-// them refuses is not counted for the rate limits. Then come the
-// rate limits, unless the client is in SWWAF_RATE_LIMIT_EXEMPT_NETS or the
-// request's path is exempt under SWWAF_RATE_LIMIT_EXEMPT_PATHS, so that
-// every other request is counted, each of them by the client's limit
-// percentages, then SWWAF_TRAP_PATHS, then the rule files, then the header
-// limits, and last the Core Rule Set. A request exempt from the rate limits
-// is exempt from the byte limits too. ctx is the request's own context.
-func (rq *request) checkClient(ctx context.Context) string {
-	cfg := rq.h.config
-	if isInside(rq.client, cfg.AllowNets) {
-		return ""
+// checkClient runs the heuristics of beforeLookup on the request, then looks
+// up the client's AS number and country, then runs those of afterLookup. It
+// returns the first verdict, or nil when none gives one. A client in
+// SWWAF_ALLOW_NETS skips them all, and is not looked up. ctx is the request's
+// own context.
+func (rq *request) checkClient(ctx context.Context) *verdict {
+	if isInside(rq.client, rq.h.config.AllowNets) {
+		return nil
 	}
 
 	now := rq.h.now()
 
-	if isInside(rq.client, cfg.DenyNets) {
-		return requestlog.ActionDenied
-	}
-
-	if rq.banned(now) {
-		return requestlog.ActionBanned
+	v := rq.runHeuristics(ctx, beforeLookup(), now)
+	if v != nil {
+		return v
 	}
 
 	rq.lookUp(ctx, now)
@@ -220,59 +210,7 @@ func (rq *request) checkClient(ctx context.Context) string {
 	// again: a request counted at the time it arrived could be counted
 	// after a later one of its client's, which the rate limits would take
 	// for the clock set back.
-	now = rq.h.now()
-
-	if rq.countryDenied() {
-		return requestlog.ActionCountryDenied
-	}
-
-	if rq.blocklistDenied() {
-		return requestlog.ActionDenied
-	}
-
-	if rq.crowdSecBanned(now) {
-		return requestlog.ActionBanned
-	}
-
-	if rq.dnsblDenied(ctx) || rq.abuseIPDBDenied(ctx) {
-		return requestlog.ActionDenied
-	}
-
-	rq.counted = rq.countedByRateLimits()
-	if rq.counted {
-		rq.limitPercent, rq.bytesPercent = rq.limitPercentages()
-		rq.line.LimitPercent, rq.line.LimitPercentSetting = rq.limitPercent.logged()
-		rq.line.BytesPercent, rq.line.BytesPercentSetting = rq.bytesPercent.logged()
-	}
-
-	if rq.counted && rq.limitBroken(now) {
-		return requestlog.ActionRateLimited
-	}
-
-	if rq.trapPath(now) {
-		return requestlog.ActionBanned
-	}
-
-	action := rq.checkRules(now)
-	if action != "" {
-		return action
-	}
-
-	if rq.overHeaderLimits() {
-		return requestlog.ActionTooLarge
-	}
-
-	return rq.checkCoreRuleSet()
-}
-
-// countedByRateLimits reports whether the rate limits count the request: its
-// client is not in SWWAF_RATE_LIMIT_EXEMPT_NETS, and its path is not exempt
-// under SWWAF_RATE_LIMIT_EXEMPT_PATHS.
-func (rq *request) countedByRateLimits() bool {
-	cfg := rq.h.config
-
-	return !isInside(rq.client, cfg.RateLimitExemptNets) &&
-		!pathExempt(rq.in, cfg.RateLimitExemptPaths)
+	return rq.runHeuristics(ctx, afterLookup(), rq.h.now())
 }
 
 // pathExempt reports whether r is exempt under prefixes,

internal/servewaf/requestlog_test.go

@@ -1,6 +1,7 @@
-package proxy_test
+package servewaf_test
 
 import (
+	"encoding/json"
 	"io"
 	"math"
 	"net/http"
@@ -10,9 +11,9 @@ import (
 	"testing"
 	"time"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -220,7 +221,7 @@ func TestTimingsAreInOrder(t *testing.T) {
 	wantStatus(t, do(t, req), http.StatusForbidden)
 	refused := out.endedLines(t, 2)[1]
 
-	wantStatus(t, get(t, server.Addr, proxy.HealthPath), http.StatusOK)
+	wantStatus(t, get(t, server.Addr, servewaf.HealthPath), http.StatusOK)
 	health := out.endedLines(t, 3)[2]
 
 	// A request passed to the app has every timing; one refused, none of
@@ -272,6 +273,48 @@ func wantTimings(t *testing.T, line logLine, want ...string) {
 	}
 }
 
+// wantHeuristic checks that line names heuristic as the one that refused the
+// request, with figures, a JSON object. A heuristic of "" with figures "null" is
+// a line that names none.
+func wantHeuristic(t *testing.T, line logLine, heuristic, figures string) {
+	t.Helper()
+
+	if line.Heuristic != heuristic ||
+		!reflect.DeepEqual(line.HeuristicFigures, decodeFigures(t, figures)) {
+		t.Errorf("log line has heuristic %q with heuristic_figures %v, want %q with %s",
+			line.Heuristic, line.HeuristicFigures, heuristic, figures)
+	}
+}
+
+// wantAfterAnswerHeuristic checks after_answer_heuristic and
+// after_answer_heuristic_figures as wantHeuristic checks heuristic and
+// heuristic_figures.
+func wantAfterAnswerHeuristic(t *testing.T, line logLine, heuristic, figures string) {
+	t.Helper()
+
+	if line.AfterAnswerHeuristic != heuristic ||
+		!reflect.DeepEqual(line.AfterAnswerHeuristicFigures, decodeFigures(t, figures)) {
+		t.Errorf("log line has after_answer_heuristic %q with "+
+			"after_answer_heuristic_figures %v, want %q with %s",
+			line.AfterAnswerHeuristic, line.AfterAnswerHeuristicFigures, heuristic, figures)
+	}
+}
+
+// decodeFigures decodes figures, a JSON object of a heuristic's figures, as
+// the log line's figures are decoded.
+func decodeFigures(t *testing.T, figures string) map[string]any {
+	t.Helper()
+
+	var decoded map[string]any
+
+	err := json.Unmarshal([]byte(figures), &decoded)
+	if err != nil {
+		t.Fatalf("decode %s: %v", figures, err)
+	}
+
+	return decoded
+}
+
 // microseconds is a timing in whole microseconds.
 func microseconds(milliseconds float64) int64 {
 	return int64(math.Round(milliseconds * 1000))

internal/servewaf/rulefiles.go

@@ -0,0 +1,55 @@
+package servewaf
+
+// The heuristic rule_files. It reads the rules of the rule files, which
+// SWWAF_RULES_DIR and SWWAF_RULES_ENABLED name.
+
+import (
+	"context"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/rules"
+)
+
+// ruleFiles checks the request against the rules of the rule files at now,
+// notes the ids of those it matches in the log line, and refuses the request
+// when the last rule it matches refuses it: with ActionRuleBlocked for a block
+// rule, and ActionBanned for a ban rule. A ban rule bans the client's netblock
+// for a clear sign of attack, or in observe mode raises the alert for the ban
+// it would have made. Either rule's match is noted as an offence, for the
+// client's history. Its figures are the rule's id and action.
+type ruleFiles struct{}
+
+func (ruleFiles) name() string { return "rule_files" }
+
+func (ruleFiles) check(_ context.Context, rq *request, now time.Time) *verdict {
+	matched := rq.h.rules.Match(rq.in)
+
+	for _, rule := range matched {
+		rq.line.RuleIDs = append(rq.line.RuleIDs, rule.ID)
+		rq.h.metrics.RuleMatched(rule.ID, rule.Action)
+	}
+
+	if len(matched) == 0 {
+		return nil
+	}
+
+	// Only the last rule matched can refuse the request.
+	last := matched[len(matched)-1]
+	figures := map[string]any{"rule_id": last.ID, "rule_action": last.Action}
+
+	switch last.Action {
+	case rules.ActionBlock:
+		rq.ruleBlocked = true
+
+		return &verdict{action: requestlog.ActionRuleBlocked, figures: figures}
+	case rules.ActionBan:
+		rq.attack = true
+		rq.banForAttack(now, bans.Notes{RuleID: last.ID, Target: last.Target})
+
+		return &verdict{action: requestlog.ActionBanned, figures: figures}
+	default:
+		return nil
+	}
+}

internal/servewaf/rulefiles_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
@@ -93,6 +93,21 @@ func TestEachRuleAction(t *testing.T) {
 	s.get(client, http.StatusTooManyRequests, requestlog.ActionBanned)
 }
 
+func TestRuleRefusalNamesItsHeuristicAndTheRule(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{
+		rulesDir: writeRules(t, "noted path log ^/\n"+testRules),
+	})
+
+	line := s.request(client, "/blocked", http.StatusForbidden,
+		requestlog.ActionRuleBlocked)
+	wantHeuristic(t, line, "rule_files", `{"rule_id": "blocked", "rule_action": "block"}`)
+
+	line = s.request(client, "/.env", http.StatusForbidden, requestlog.ActionBanned)
+	wantHeuristic(t, line, "rule_files", `{"rule_id": "probe", "rule_action": "ban"}`)
+}
+
 func TestNextClearSignOfAttackAfterABanBansPermanently(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/servewaf.go

@@ -1,7 +1,8 @@
-package proxy
+package servewaf
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -52,13 +53,6 @@ const ReportPath = "/_smallwebwaf/report"
 // QuestionBodyMaxBytes is the most of a visitor's body a question carries.
 const QuestionBodyMaxBytes = 64 << 10
 
-// The header limits: the most cookies and header fields a request may have
-// when the checks reach the Core Rule Set. Real clients never reach them.
-const (
-	maxCookies      = 50
-	maxHeaderFields = 100
-)
-
 const (
 	// maxAwaitingReport is the most answered requests held until their
 	// reports come. Past it, the request answered longest ago is dropped.
@@ -103,13 +97,13 @@ type Report struct {
 	DurationUpstreamTotal float64 `json:"duration_upstream_total"`
 }
 
-// NewServeWAF returns the server `smallwebwaf servewaf` runs. It answers
+// New returns the server `smallwebwaf servewaf` runs. It answers
 // rproxy's questions, takes rproxy's reports and answers its own endpoints. It
 // passes nothing to an app. rproxy applies the size and time limits to the
 // visitor. Go's default limit on a request's line and headers, 1 MiB, stays: it
 // is far above rproxy's, and a question refused for its size would have rproxy
 // let the request through.
-func NewServeWAF(params Params) *Server {
+func New(params Params) *Server {
 	h := newHandler(params)
 
 	return &Server{
@@ -147,48 +141,20 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 // refusedWhateverTheAnswer reports whether the request is one that does not wait
 // for GeoJS, since the checks will refuse it at now whatever GeoJS answers about
-// its client: it is over the header limits, a blocklist lists its client while
-// SWWAF_BLOCKLIST_ACTION is deny, the CrowdSec decision list lists it, or it is
-// over a whole rate limit. In observe mode, which refuses nothing, none is.
-// rproxy lets a request through when servewaf answers too late.
+// its client: the heuristic crowdsec, header_limits, blocklists or rate_limits
+// will refuse it, as a function in that heuristic's file says. In observe mode,
+// which refuses nothing, none is. rproxy lets a request through when servewaf
+// answers too late.
 func (rq *request) refusedWhateverTheAnswer(now time.Time) bool {
 	if rq.h.config.Observe {
 		return false
 	}
 
-	lists := rq.h.lists
-	_, decided := lists.CrowdSecDecision(rq.client, now)
+	_, decided := rq.crowdSecDecisionInForce(now)
 
-	return decided || rq.overHeaderLimits() ||
-		(rq.h.config.BlocklistAction == deny && len(lists.ListedBy(rq.client)) > 0) ||
-		(rq.countedByRateLimits() &&
-			rq.h.limiter.OverARateLimit(rq.h.clientGroup(rq.client), now))
-}
-
-// overHeaderLimits reports whether servewaf refuses the request for its
-// headers: it has more than maxHeaderFields fields, each value of a header sent
-// twice being one, or more than maxCookies cookies, each part of a Cookie header
-// between semicolons being one unless it is empty or only spaces and tabs. The
-// Core Rule Set runs each of its rules on each cookie, so that thousands of small
-// cookies keep it busy for over a second. It trims only spaces and control
-// characters, of which a header value can hold only tabs, so a part of Unicode
-// spaces is a cookie to it.
-func (rq *request) overHeaderLimits() bool {
-	fields, cookies := 0, 0
-
-	for _, values := range rq.in.Header {
-		fields += len(values)
-	}
-
-	for _, value := range rq.in.Header.Values("Cookie") {
-		for part := range strings.SplitSeq(value, ";") {
-			if strings.Trim(part, " \t") != "" {
-				cookies++
-			}
-		}
-	}
-
-	return fields > maxHeaderFields || cookies > maxCookies
+	return decided || overHeaderLimits(rq.headerCounts()) ||
+		rq.refusedByBlocklists(rq.h.lists.ListedBy(rq.client)) ||
+		rq.overAWholeRateLimit(now)
 }
 
 // answerQuestion runs the checks on the visitor's request a question
@@ -219,18 +185,18 @@ func (h *handler) answerQuestion(w http.ResponseWriter, r *http.Request) {
 
 	if refused == nil && !underOwnPrefix {
 		// In observe mode, what enforce mode would have refused counts here.
-		defer rq.countRefusal()
+		defer rq.runAfterAnswer(r.Context())
 
 		rq.allow()
 
 		return
 	}
 
-	// The last deferred runs first: countRefusal before addToHistory, so that a
-	// broken error burst is in the client's history.
+	// The last deferred runs first: runAfterAnswer before addToHistory, so that
+	// a broken refusal limit is in the client's history.
 	defer rq.addToHistory()
 	defer rq.countAnomalies()
-	defer rq.countRefusal()
+	defer rq.runAfterAnswer(r.Context())
 
 	if refused != nil {
 		rq.deny(*refused)
@@ -412,7 +378,7 @@ func (h *handler) takeReport(w http.ResponseWriter, r *http.Request) {
 	// Remove reports true to one report only, of several that name the id. A
 	// question still being handled is held as nil.
 	if found && held != nil && h.awaitingReport.Remove(report.RequestID) {
-		h.finishWith(held, report)
+		h.finishWith(r.Context(), held, report)
 	}
 
 	w.WriteHeader(http.StatusNoContent)
@@ -475,11 +441,11 @@ func (report *Report) checkRanges() error {
 
 // finishWith finishes a request with what its report says, and writes the
 // request's last log line, which holds its decision's fields and the report's.
-// For an allowed request it first counts the request's bytes, and adds it to its
-// client's history, the anomaly counters and the metrics, with the status and
-// bytes the report gives. A denied request's counting was finished at its
-// decision.
-func (h *handler) finishWith(held *decision, report Report) {
+// For an allowed request it first runs the heuristics of onReport, and adds the
+// request to its client's history, the anomaly counters and the metrics, with
+// the status and bytes the report gives. A denied request's counting was
+// finished at its decision. ctx is the report's own context.
+func (h *handler) finishWith(ctx context.Context, held *decision, report Report) {
 	rq := &request{
 		decision:     *held,
 		h:            h,
@@ -496,7 +462,7 @@ func (h *handler) finishWith(held *decision, report Report) {
 	if rq.allowed {
 		rq.line.DurationUpstreamTotal = &report.DurationUpstreamTotal
 
-		rq.countBytes()
+		rq.runBanningHeuristics(ctx, onReport())
 		rq.countAnomalies()
 		rq.addToHistory()
 

internal/servewaf/servewaf_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"context"
@@ -19,9 +19,9 @@ import (
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/bans"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 const (
@@ -57,7 +57,7 @@ type serveWAF struct {
 	t      *testing.T
 	addr   string
 	out    *output
-	server *proxy.Server
+	server *servewaf.Server
 	clock  *clock
 	queue  *alerts.Queue
 }
@@ -67,13 +67,13 @@ type serveWAF struct {
 func startServeWAF(t *testing.T, geojsURL string, env map[string]string) *serveWAF {
 	t.Helper()
 
-	return startServeWAFWith(t, geojsURL, env, func(*proxy.Server) {})
+	return startServeWAFWith(t, geojsURL, env, func(*servewaf.Server) {})
 }
 
 // startServeWAFWith is startServeWAF with change applied to the server before
 // it starts.
 func startServeWAFWith(
-	t *testing.T, geojsURL string, env map[string]string, change func(*proxy.Server),
+	t *testing.T, geojsURL string, env map[string]string, change func(*servewaf.Server),
 ) *serveWAF {
 	t.Helper()
 
@@ -103,8 +103,8 @@ func (s *serveWAF) questionWith(
 
 	req := newRequest(s.t, method, s.addr, path, body)
 	req.Host = host
-	req.Header.Set(proxy.ClientHeader, from)
-	req.Header.Set(proxy.PeerHeader, rproxyPeer)
+	req.Header.Set(servewaf.ClientHeader, from)
+	req.Header.Set(servewaf.PeerHeader, rproxyPeer)
 	req.Header.Set(requestIDHeader, rand.Text())
 
 	return req
@@ -131,13 +131,13 @@ func (s *serveWAF) allowed(from string) string {
 	s.t.Helper()
 
 	req := s.question(siteA, from, "/")
-	wantDisposition(s.t, do(s.t, req), http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(s.t, do(s.t, req), http.StatusOK, servewaf.DispositionAllow)
 
 	return req.Header.Get(requestIDHeader)
 }
 
 // report sends rproxy's report and returns the answer.
-func (s *serveWAF) report(report proxy.Report) answer {
+func (s *serveWAF) report(report servewaf.Report) answer {
 	s.t.Helper()
 
 	body, err := json.Marshal(report)
@@ -152,7 +152,7 @@ func (s *serveWAF) report(report proxy.Report) answer {
 func (s *serveWAF) reportBody(body string) answer {
 	s.t.Helper()
 
-	return do(s.t, newRequest(s.t, http.MethodPost, s.addr, proxy.ReportPath,
+	return do(s.t, newRequest(s.t, http.MethodPost, s.addr, servewaf.ReportPath,
 		strings.NewReader(body)))
 }
 
@@ -161,7 +161,7 @@ func (s *serveWAF) reportBody(body string) answer {
 func (s *serveWAF) passedOn(from string) {
 	s.t.Helper()
 
-	got := s.report(proxy.Report{
+	got := s.report(servewaf.Report{
 		RequestID:     s.allowed(from),
 		Status:        http.StatusOK,
 		RequestBytes:  bodyBytes,
@@ -182,7 +182,7 @@ func (s *serveWAF) history() ratelimit.History {
 func (s *serveWAF) metrics() string {
 	s.t.Helper()
 
-	req := newRequest(s.t, http.MethodGet, s.addr, proxy.MetricsPath, http.NoBody)
+	req := newRequest(s.t, http.MethodGet, s.addr, servewaf.MetricsPath, http.NoBody)
 	req.Header.Set("Authorization", bearer)
 
 	got := do(s.t, req)
@@ -196,7 +196,7 @@ func wantDisposition(t *testing.T, got answer, status int, disposition string) {
 	t.Helper()
 	wantStatus(t, got, status)
 
-	if answered := got.header.Get(proxy.DispositionHeader); answered != disposition {
+	if answered := got.header.Get(servewaf.DispositionHeader); answered != disposition {
 		t.Errorf("answered with disposition %q, want %q", answered, disposition)
 	}
 }
@@ -248,10 +248,10 @@ func TestQuestionAllowedIsAnsweredAndLogged(t *testing.T) {
 	req := s.question(siteA, client, "/page?q=1&token=visible")
 	req.Header.Set(requestIDHeader, "the-id")
 	req.Header.Set("X-Forwarded-Proto", "https")
-	req.Header.Set(proxy.ContentLengthHeader, "1234")
+	req.Header.Set(servewaf.ContentLengthHeader, "1234")
 
 	got := do(t, req)
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 	wantBody(t, got, "")
 
 	if id := got.header.Get(requestIDHeader); id != "" {
@@ -278,7 +278,7 @@ func TestIPv6VisitorIsCountedInItsGroup(t *testing.T) {
 	s.allowed("2001:db8::1")
 
 	got := s.ask("2001:db8::2", "/")
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 }
 
 func TestIPv4VisitorInIPv6FormIsTheIPv4Client(t *testing.T) {
@@ -287,9 +287,9 @@ func TestIPv4VisitorInIPv6FormIsTheIPv4Client(t *testing.T) {
 	s := startServeWAF(t, "", map[string]string{denyNets: client})
 
 	req := s.question(siteA, "::ffff:"+client, "/")
-	req.Header.Set(proxy.PeerHeader, "::ffff:"+rproxyPeer)
+	req.Header.Set(servewaf.PeerHeader, "::ffff:"+rproxyPeer)
 
-	wantDisposition(t, do(t, req), http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, do(t, req), http.StatusForbidden, servewaf.DispositionDeny)
 
 	line := s.out.requestLine(t)
 	if line.ClientIP != client || line.PeerIP != rproxyPeer {
@@ -305,13 +305,13 @@ func TestMalformedQuestionGets400AndAWarningAndNoLine(t *testing.T) {
 		change func(*http.Request)
 	}{
 		{"client not an address", func(req *http.Request) {
-			req.Header.Set(proxy.ClientHeader, "not an address")
+			req.Header.Set(servewaf.ClientHeader, "not an address")
 		}},
 		{"client empty", func(req *http.Request) {
-			req.Header.Set(proxy.ClientHeader, "")
+			req.Header.Set(servewaf.ClientHeader, "")
 		}},
 		{"client address with a zone", func(req *http.Request) {
-			req.Header.Set(proxy.ClientHeader, "2001:db8::1%eth0")
+			req.Header.Set(servewaf.ClientHeader, "2001:db8::1%eth0")
 		}},
 		{"id absent", func(req *http.Request) {
 			req.Header.Del(requestIDHeader)
@@ -353,7 +353,7 @@ func TestLongestValidIDIsTaken(t *testing.T) {
 
 	req := s.question(siteA, client, "/")
 	req.Header.Set(requestIDHeader, strings.Repeat("x", 128))
-	wantDisposition(t, do(t, req), http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, do(t, req), http.StatusOK, servewaf.DispositionAllow)
 }
 
 func TestQuestionWithABodyOver64KiBGets400(t *testing.T) {
@@ -361,15 +361,15 @@ func TestQuestionWithABodyOver64KiBGets400(t *testing.T) {
 
 	s := startServeWAF(t, "", nil)
 
-	over := strings.NewReader(strings.Repeat("x", proxy.QuestionBodyMaxBytes+1))
+	over := strings.NewReader(strings.Repeat("x", servewaf.QuestionBodyMaxBytes+1))
 	got := do(t, s.questionWith(http.MethodPost, siteA, client, "/", over))
 	wantDisposition(t, got, http.StatusBadRequest, "")
 	wantProcessMessages(t, s, "a question is refused", 1)
 	wantNoRequestLines(t, s)
 
-	whole := strings.NewReader(strings.Repeat("x", proxy.QuestionBodyMaxBytes))
+	whole := strings.NewReader(strings.Repeat("x", servewaf.QuestionBodyMaxBytes))
 	got = do(t, s.questionWith(http.MethodPost, siteA, client, "/", whole))
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 }
 
 func TestQuestionWithAHeldIDIsRefused(t *testing.T) {
@@ -385,15 +385,15 @@ func TestQuestionWithAHeldIDIsRefused(t *testing.T) {
 	wantProcessMessages(t, s, "a question is refused", 1)
 
 	// A denied request's id is held as well.
-	denied := s.question(siteA, otherClient, proxy.HealthPath)
-	wantDisposition(t, do(t, denied), http.StatusNotFound, proxy.DispositionDeny)
+	denied := s.question(siteA, otherClient, servewaf.HealthPath)
+	wantDisposition(t, do(t, denied), http.StatusNotFound, servewaf.DispositionDeny)
 
 	again = s.question(siteA, client, "/")
 	again.Header.Set(requestIDHeader, denied.Header.Get(requestIDHeader))
 	wantDisposition(t, do(t, again), http.StatusBadRequest, "")
 
 	// The report ends the holding, and the refused questions changed nothing.
-	got := s.report(proxy.Report{RequestID: id, ResponseBytes: answerBytes})
+	got := s.report(servewaf.Report{RequestID: id, ResponseBytes: answerBytes})
 	wantStatus(t, got, http.StatusNoContent)
 
 	if history := s.history(); history.ResponseBytes != answerBytes {
@@ -402,7 +402,7 @@ func TestQuestionWithAHeldIDIsRefused(t *testing.T) {
 
 	again = s.question(siteA, client, "/")
 	again.Header.Set(requestIDHeader, id)
-	wantDisposition(t, do(t, again), http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, do(t, again), http.StatusOK, servewaf.DispositionAllow)
 }
 
 func TestReportNeverReachesAQuestionStillBeingHandled(t *testing.T) {
@@ -436,7 +436,7 @@ func TestReportNeverReachesAQuestionStillBeingHandled(t *testing.T) {
 
 	// A report for a question not yet answered is ignored, and that question's
 	// id is taken.
-	got := s.report(proxy.Report{RequestID: id, ResponseBytes: 1000})
+	got := s.report(servewaf.Report{RequestID: id, ResponseBytes: 1000})
 	wantStatus(t, got, http.StatusNoContent)
 
 	// This would wait on the same lookup were the id not taken.
@@ -451,7 +451,7 @@ func TestReportNeverReachesAQuestionStillBeingHandled(t *testing.T) {
 
 	select {
 	case got := <-answered:
-		wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+		wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 	case <-time.After(waitLimit):
 		t.Fatal("the question got no answer")
 	}
@@ -466,7 +466,7 @@ func TestReportNeverReachesAQuestionStillBeingHandled(t *testing.T) {
 	}
 
 	// The true report comes after, and is the one that counts.
-	got = s.report(proxy.Report{RequestID: id, ResponseBytes: answerBytes})
+	got = s.report(servewaf.Report{RequestID: id, ResponseBytes: answerBytes})
 	wantStatus(t, got, http.StatusNoContent)
 
 	if history := s.history(); history.ResponseBytes != answerBytes {
@@ -484,13 +484,13 @@ func TestPeerAbsentOrUnreadableIsAnsweredAndLoggedInvalid(t *testing.T) {
 			s := startServeWAF(t, "", nil)
 
 			req := s.question(siteA, client, "/")
-			req.Header.Del(proxy.PeerHeader)
+			req.Header.Del(servewaf.PeerHeader)
 
 			if peer != "" {
-				req.Header.Set(proxy.PeerHeader, peer)
+				req.Header.Set(servewaf.PeerHeader, peer)
 			}
 
-			wantDisposition(t, do(t, req), http.StatusOK, proxy.DispositionAllow)
+			wantDisposition(t, do(t, req), http.StatusOK, servewaf.DispositionAllow)
 
 			if line := s.out.requestLine(t); line.PeerIP != "invalid IP" {
 				t.Errorf("log line has peer_ip %q, want invalid IP", line.PeerIP)
@@ -511,8 +511,8 @@ func TestContentLengthUnreadableOrNegativeCountsAsAbsent(t *testing.T) {
 			})
 
 			req := s.question(siteA, client, "/")
-			req.Header.Set(proxy.ContentLengthHeader, announced)
-			wantDisposition(t, do(t, req), http.StatusOK, proxy.DispositionAllow)
+			req.Header.Set(servewaf.ContentLengthHeader, announced)
+			wantDisposition(t, do(t, req), http.StatusOK, servewaf.DispositionAllow)
 
 			if line := s.out.requestLine(t); line.ContentLength != 0 {
 				t.Errorf("log line has content_length %d, want none", line.ContentLength)
@@ -527,13 +527,13 @@ func TestHeaderSentTwiceUsesItsFirstValue(t *testing.T) {
 	s := startServeWAF(t, "", nil)
 
 	req := s.question(siteA, client, "/")
-	req.Header.Add(proxy.ClientHeader, otherClient)
-	req.Header.Add(proxy.PeerHeader, "172.18.0.3")
+	req.Header.Add(servewaf.ClientHeader, otherClient)
+	req.Header.Add(servewaf.PeerHeader, "172.18.0.3")
 	req.Header.Set(requestIDHeader, "first")
 	req.Header.Add(requestIDHeader, "second")
-	req.Header.Set(proxy.ContentLengthHeader, "1234")
-	req.Header.Add(proxy.ContentLengthHeader, "5678")
-	wantDisposition(t, do(t, req), http.StatusOK, proxy.DispositionAllow)
+	req.Header.Set(servewaf.ContentLengthHeader, "1234")
+	req.Header.Add(servewaf.ContentLengthHeader, "5678")
+	wantDisposition(t, do(t, req), http.StatusOK, servewaf.DispositionAllow)
 
 	line := s.out.requestLine(t)
 	if line.ClientIP != client || line.PeerIP != rproxyPeer ||
@@ -562,7 +562,7 @@ func sendQuestionWithPartOfItsBody(t *testing.T, conn net.Conn) {
 	_, err := fmt.Fprintf(conn,
 		"POST / HTTP/1.1\r\nHost: %s\r\n%s: %s\r\n%s: an-id\r\n"+
 			"Content-Length: 100\r\n\r\npart",
-		siteA, proxy.ClientHeader, client, requestIDHeader)
+		siteA, servewaf.ClientHeader, client, requestIDHeader)
 	if err != nil {
 		t.Fatalf("send the question: %v", err)
 	}
@@ -592,7 +592,7 @@ func TestQuestionWhoseBodyStopsArrivingGetsNoAnswer(t *testing.T) {
 			t.Parallel()
 
 			s := startServeWAFWith(t, "", map[string]string{metricsToken: token},
-				func(server *proxy.Server) { server.ReadTimeout = readTimeout })
+				func(server *servewaf.Server) { server.ReadTimeout = readTimeout })
 
 			conn := dial(t, s.addr)
 			sendQuestionWithPartOfItsBody(t, conn)
@@ -615,7 +615,7 @@ func TestQuestionWhoseBodyStopsArrivingGetsNoAnswer(t *testing.T) {
 			// The id was not taken.
 			again := s.question(siteA, client, "/")
 			again.Header.Set(requestIDHeader, "an-id")
-			wantDisposition(t, do(t, again), http.StatusOK, proxy.DispositionAllow)
+			wantDisposition(t, do(t, again), http.StatusOK, servewaf.DispositionAllow)
 		})
 	}
 }
@@ -632,7 +632,7 @@ func TestQuestionDeniedGetsTheBanResponse(t *testing.T) {
 			})
 
 			got := s.ask(client, "/")
-			wantDisposition(t, got, status, proxy.DispositionDeny)
+			wantDisposition(t, got, status, servewaf.DispositionDeny)
 			wantBody(t, got, http.StatusText(status)+"\n")
 			wantLine(t, s.out.requestLine(t), status, requestlog.ActionDenied)
 		})
@@ -647,7 +647,7 @@ func TestBanResponseCloseIsAnAnswerOfItsOwn(t *testing.T) {
 	})
 
 	got := s.ask(client, "/")
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionClose)
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionClose)
 	wantBody(t, got, "")
 	// The visitor is sent nothing.
 	wantLine(t, s.out.requestLine(t), 0, requestlog.ActionDenied)
@@ -664,12 +664,12 @@ func TestBlockRuleIsDeniedWith403AndABanRuleWithTheBanResponse(t *testing.T) {
 	})
 
 	got := s.ask(client, "/blocked")
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 	wantLine(t, s.out.requestLine(t), http.StatusForbidden,
 		requestlog.ActionRuleBlocked)
 
 	got = s.ask(client, "/.env")
-	wantDisposition(t, got, http.StatusTooManyRequests, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusTooManyRequests, servewaf.DispositionDeny)
 	wantLine(t, s.out.requestLines(t, 2)[1], http.StatusTooManyRequests,
 		requestlog.ActionBanned)
 }
@@ -681,15 +681,17 @@ func TestQuestionUnderTheOwnPrefixIsDeniedWith404AfterTheChecks(t *testing.T) {
 		metricsToken: token, denyNets: otherClient,
 	})
 
-	for _, path := range []string{proxy.HealthPath, proxy.MetricsPath, proxy.ReportPath} {
+	for _, path := range []string{
+		servewaf.HealthPath, servewaf.MetricsPath, servewaf.ReportPath,
+	} {
 		got := s.ask(client, path)
-		wantDisposition(t, got, http.StatusNotFound, proxy.DispositionDeny)
+		wantDisposition(t, got, http.StatusNotFound, servewaf.DispositionDeny)
 	}
 
 	wantLine(t, s.out.requestLine(t), http.StatusNotFound, requestlog.ActionAdmin)
 
-	got := s.ask(otherClient, proxy.MetricsPath)
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	got := s.ask(otherClient, servewaf.MetricsPath)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 }
 
 func TestObserveModeAllowsAndLogsWhatEnforceModeWouldHaveDone(t *testing.T) {
@@ -698,7 +700,7 @@ func TestObserveModeAllowsAndLogsWhatEnforceModeWouldHaveDone(t *testing.T) {
 	s := startServeWAF(t, "", map[string]string{mode: observe, denyNets: client})
 
 	got := s.ask(client, "/")
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 
 	line := s.out.requestLine(t)
 	wantLine(t, line, http.StatusOK, requestlog.ActionForward)
@@ -714,7 +716,7 @@ func TestObserveModeRefusalAnsweredAllowCountsForTheErrorBurst(t *testing.T) {
 
 	for range 2 {
 		got := s.ask(client, "/blocked")
-		wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+		wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 	}
 
 	lines := s.out.requestLines(t, 2)
@@ -733,7 +735,7 @@ func TestDeniedQuestionCountsForTheErrorBurst(t *testing.T) {
 
 	for range 2 {
 		got := s.ask(client, "/blocked")
-		wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+		wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 	}
 
 	lines := s.out.requestLines(t, 2)
@@ -762,7 +764,7 @@ func TestAllowCarriesTheLookupHeadersWhileTheSettingIsSet(t *testing.T) {
 			})
 
 			got := s.ask(fromDE, "/")
-			wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+			wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 
 			asn, country := got.header.Get("X-Client-Asn"), got.header.Get("X-Client-Country")
 			if asn != tc.wantASN || country != tc.wantCountry {
@@ -787,7 +789,7 @@ func TestReportCountsTowardAByteLimitWhichThenBans(t *testing.T) {
 	}
 
 	// 100 bytes are over the limit of 99.
-	got := s.report(proxy.Report{
+	got := s.report(servewaf.Report{
 		RequestID: id, Status: http.StatusBadGateway,
 		RequestBytes: bodyBytes, ResponseBytes: answerBytes,
 	})
@@ -811,7 +813,7 @@ func TestReportCountsTowardAByteLimitWhichThenBans(t *testing.T) {
 	}
 
 	got = s.ask(client, "/")
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 }
 
 func TestReportCountsAtThePercentageItsQuestionWasGiven(t *testing.T) {
@@ -825,10 +827,10 @@ func TestReportCountsAtThePercentageItsQuestionWasGiven(t *testing.T) {
 	})
 
 	s.passedOn(fromKP)
-	wantDisposition(t, s.ask(fromKP, "/"), http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, s.ask(fromKP, "/"), http.StatusOK, servewaf.DispositionAllow)
 
 	s.passedOn(fromDE)
-	wantDisposition(t, s.ask(fromDE, "/"), http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, s.ask(fromDE, "/"), http.StatusForbidden, servewaf.DispositionDeny)
 }
 
 func TestReportAddsTheRequestToItsClientsHistoryAndTheAnomalyCounters(t *testing.T) {
@@ -846,7 +848,7 @@ func TestReportAddsTheRequestToItsClientsHistoryAndTheAnomalyCounters(t *testing
 		t.Errorf("anomaly counters %v before the report, want none", counters)
 	}
 
-	got := s.report(proxy.Report{
+	got := s.report(servewaf.Report{
 		RequestID: id, Status: http.StatusBadGateway,
 		RequestBytes: bodyBytes, ResponseBytes: answerBytes,
 	})
@@ -874,7 +876,7 @@ func TestDeniedRequestIsFinishedAtItsDecision(t *testing.T) {
 	s.allowed(client)
 
 	denied := s.question(siteA, client, "/")
-	wantDisposition(t, do(t, denied), http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, do(t, denied), http.StatusForbidden, servewaf.DispositionDeny)
 
 	counters := s.server.Anomalies.Snapshot()
 	if len(counters) != 1 || counters[0].Minute.Current != 1 {
@@ -891,7 +893,7 @@ func TestDeniedRequestIsFinishedAtItsDecision(t *testing.T) {
 
 	wantMetric(t, s.metrics(), series, 1)
 
-	got := s.report(proxy.Report{
+	got := s.report(servewaf.Report{
 		RequestID: denied.Header.Get(requestIDHeader), Status: http.StatusForbidden,
 		ResponseBytes: 1000, DurationTotal: 2,
 	})
@@ -924,7 +926,7 @@ func TestMetricsCountAnAllowedRequestFromItsReport(t *testing.T) {
 	wantMetric(t, metrics, `smallwebwaf_requests_in_flight{instance="`+alertInstance+`"}`,
 		1) // the scrape itself
 
-	got := s.report(proxy.Report{
+	got := s.report(servewaf.Report{
 		RequestID: id, Status: http.StatusBadGateway,
 		RequestBytes: bodyBytes, ResponseBytes: answerBytes,
 		DurationTotal: 5, DurationUpstreamTotal: 4,
@@ -942,7 +944,7 @@ func TestMetricsCountAnAllowedRequestFromItsReport(t *testing.T) {
 	// check needs a server that has not been scraped yet.
 	unscraped := startServeWAF(t, "", map[string]string{metricsToken: token})
 
-	got = unscraped.report(proxy.Report{
+	got = unscraped.report(servewaf.Report{
 		RequestID: unscraped.allowed(client), Status: http.StatusBadGateway, DurationTotal: 5,
 	})
 	wantStatus(t, got, http.StatusNoContent)
@@ -955,7 +957,7 @@ func TestReportForARequestNotHeldIsIgnored(t *testing.T) {
 
 	s := startServeWAF(t, "", map[string]string{bytesLimitPerMinute: byteLimit})
 
-	got := s.report(proxy.Report{RequestID: "no-such-request", ResponseBytes: 1000})
+	got := s.report(servewaf.Report{RequestID: "no-such-request", ResponseBytes: 1000})
 	wantStatus(t, got, http.StatusNoContent)
 
 	if clients := s.server.Limiter.Snapshot(); len(clients) != 0 {
@@ -972,7 +974,7 @@ func TestReportForARequestNotHeldIsIgnored(t *testing.T) {
 	// A second report of the same request does not count it twice.
 	id := s.allowed(client)
 	for range 2 {
-		got = s.report(proxy.Report{RequestID: id, ResponseBytes: answerBytes})
+		got = s.report(servewaf.Report{RequestID: id, ResponseBytes: answerBytes})
 		wantStatus(t, got, http.StatusNoContent)
 	}
 
@@ -1160,7 +1162,7 @@ func TestBytesAtTheirMostEachWayBanRatherThanOverflow(t *testing.T) {
 
 	s := startServeWAF(t, "", map[string]string{bytesLimitPerMinute: byteLimit})
 
-	got := s.report(proxy.Report{
+	got := s.report(servewaf.Report{
 		RequestID: s.allowed(client), Status: http.StatusOK,
 		RequestBytes: reportedBytesLimit, ResponseBytes: reportedBytesLimit,
 	})
@@ -1245,9 +1247,9 @@ func TestReportWritesTheLastLineWithTheDecisionsAndTheReportsFields(t *testing.T
 	req.Header.Set("X-Forwarded-Proto", "https")
 	id := req.Header.Get(requestIDHeader)
 
-	wantDisposition(t, do(t, req), http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, do(t, req), http.StatusOK, servewaf.DispositionAllow)
 
-	got := s.report(proxy.Report{
+	got := s.report(servewaf.Report{
 		RequestID: id, Status: http.StatusCreated,
 		RequestBytes: bodyBytes, ResponseBytes: answerBytes,
 		DurationTotal: 12.5, DurationUpstreamTotal: 10.25,
@@ -1294,7 +1296,7 @@ func TestEveryDeniedRequestsReportGetsItsLastLine(t *testing.T) {
 			"close", map[string]string{denyNets: client, banResponse: banResponseClose}, "/",
 			0, requestlog.ActionDenied,
 		},
-		{"own prefix", nil, proxy.HealthPath, http.StatusNotFound, requestlog.ActionAdmin},
+		{"own prefix", nil, servewaf.HealthPath, http.StatusNotFound, requestlog.ActionAdmin},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
@@ -1305,7 +1307,7 @@ func TestEveryDeniedRequestsReportGetsItsLastLine(t *testing.T) {
 			id := req.Header.Get(requestIDHeader)
 			do(t, req)
 
-			got := s.report(proxy.Report{
+			got := s.report(servewaf.Report{
 				RequestID: id, Status: tc.status, ResponseBytes: 8, DurationTotal: 3,
 			})
 			wantStatus(t, got, http.StatusNoContent)
@@ -1341,18 +1343,18 @@ func TestOldestAnsweredRequestIsDroppedPastTheBound(t *testing.T) {
 			t.Fatalf("question: %v", err)
 		}
 
-		wantDisposition(t, readAnswer(res), http.StatusOK, proxy.DispositionAllow)
+		wantDisposition(t, readAnswer(res), http.StatusOK, servewaf.DispositionAllow)
 	}
 
 	// The table is full again with next and those, without oldest.
-	got := s.report(proxy.Report{RequestID: oldest, ResponseBytes: answerBytes})
+	got := s.report(servewaf.Report{RequestID: oldest, ResponseBytes: answerBytes})
 	wantStatus(t, got, http.StatusNoContent)
 
 	if counted := s.history().Requests; counted != 0 {
 		t.Errorf("history holds %d requests, want the dropped one not counted", counted)
 	}
 
-	got = s.report(proxy.Report{RequestID: next, ResponseBytes: answerBytes})
+	got = s.report(servewaf.Report{RequestID: next, ResponseBytes: answerBytes})
 	wantStatus(t, got, http.StatusNoContent)
 
 	if counted := s.history().Requests; counted != 1 {
@@ -1366,10 +1368,10 @@ func TestBanMadeThroughOneHostRefusesTheClientOnAnother(t *testing.T) {
 	s := startServeWAF(t, "", map[string]string{rulesDir: writeRules(t, testRules)})
 
 	got := do(t, s.question(siteA, client, "/.env"))
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 
 	got = do(t, s.question(siteB, client, "/"))
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 
 	lines := s.out.requestLines(t, 2)
 	if lines[0].Host != siteA || lines[1].Host != siteB {
@@ -1395,7 +1397,7 @@ func TestRequestsOnEverySiteCountTowardOneSetOfLimits(t *testing.T) {
 	s.allowed(client)
 
 	got := do(t, s.question(siteB, client, "/"))
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 }
 
 func TestOwnEndpointsAnswerOnlyWithoutTheClientHeader(t *testing.T) {
@@ -1410,13 +1412,13 @@ func TestOwnEndpointsAnswerOnlyWithoutTheClientHeader(t *testing.T) {
 		path, authorization string
 		want                int
 	}{
-		{proxy.HealthPath, "", http.StatusOK},
-		{proxy.MetricsPath, bearer, http.StatusOK},
-		{proxy.MetricsPath, "", http.StatusUnauthorized},
-		{proxy.BansPath, adminBearer, http.StatusOK},
-		{proxy.BansPath, "", http.StatusUnauthorized},
-		{proxy.ClientsPath + client, adminBearer, http.StatusOK},
-		{proxy.ReportPath, "", http.StatusNotFound},
+		{servewaf.HealthPath, "", http.StatusOK},
+		{servewaf.MetricsPath, bearer, http.StatusOK},
+		{servewaf.MetricsPath, "", http.StatusUnauthorized},
+		{servewaf.BansPath, adminBearer, http.StatusOK},
+		{servewaf.BansPath, "", http.StatusUnauthorized},
+		{servewaf.ClientsPath + client, adminBearer, http.StatusOK},
+		{servewaf.ReportPath, "", http.StatusNotFound},
 		{"/_smallwebwaf/other", "", http.StatusNotFound},
 		{"/", "", http.StatusNotFound},
 	} {
@@ -1429,9 +1431,9 @@ func TestOwnEndpointsAnswerOnlyWithoutTheClientHeader(t *testing.T) {
 		req.Header.Set("Authorization", tc.authorization)
 
 		if strings.HasPrefix(tc.path, "/_smallwebwaf/") {
-			wantDisposition(t, do(t, req), http.StatusNotFound, proxy.DispositionDeny)
+			wantDisposition(t, do(t, req), http.StatusNotFound, servewaf.DispositionDeny)
 		} else {
-			wantDisposition(t, do(t, req), http.StatusOK, proxy.DispositionAllow)
+			wantDisposition(t, do(t, req), http.StatusOK, servewaf.DispositionAllow)
 		}
 	}
 }
@@ -1441,10 +1443,11 @@ func TestOwnEndpointsLinesDoNotSayWhichOfTheTwoTheyAre(t *testing.T) {
 
 	s := startServeWAF(t, "", nil)
 
-	wantStatus(t, get(t, s.addr, proxy.HealthPath), http.StatusOK)
+	wantStatus(t, get(t, s.addr, servewaf.HealthPath), http.StatusOK)
 
 	line := s.out.requestLine(t)
-	if _, there := line.fields["servewaf_line"]; there || line.Path != proxy.HealthPath {
+	if _, there := line.fields["servewaf_line"]; there ||
+		line.Path != servewaf.HealthPath {
 		t.Errorf("the health check's log line is %+v", line.fields)
 	}
 }
@@ -1456,12 +1459,12 @@ func TestALargeBodyAnnouncedAndLongHeadersAreNoReasonToRefuse(t *testing.T) {
 
 	req := s.questionWith(http.MethodPost, siteA, client, "/",
 		strings.NewReader("a body"))
-	req.Header.Set(proxy.ContentLengthHeader, "1073741824")
+	req.Header.Set(servewaf.ContentLengthHeader, "1073741824")
 	req.Header.Set(forwardedFor, otherClient)
 	req.Header.Set("X-Long", strings.Repeat("x", 40<<10))
 
 	got := do(t, req)
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 
 	line := s.out.requestLine(t)
 	if line.ClientIP != client || line.ContentLength != 1<<30 {
@@ -1529,7 +1532,7 @@ carried     header:Content-Length                block  ^6$
 			strings.NewReader("a body"))
 
 		if tc.announced != "" {
-			req.Header.Set(proxy.ContentLengthHeader, tc.announced)
+			req.Header.Set(servewaf.ContentLengthHeader, tc.announced)
 		}
 
 		wantStatus(t, do(t, req), tc.want)
@@ -1547,19 +1550,19 @@ func TestCoreRuleSetReadsTheBodyAQuestionCarries(t *testing.T) {
 		req := s.questionWith(http.MethodPost, siteA, client, "/",
 			strings.NewReader(body))
 		req.Header.Set("Content-Type", contentType)
-		req.Header.Set(proxy.ContentLengthHeader, "100000")
+		req.Header.Set(servewaf.ContentLengthHeader, "100000")
 
 		return do(t, req)
 	}
 
 	got := ask(formData, "id=1'%20OR%20'1'='1")
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 
 	// The first 64 KiB of a longer JSON body cannot be parsed, which is no
 	// attack, so the Core Rule Set does not read it.
-	cut := `{"text":"` + strings.Repeat("x", proxy.QuestionBodyMaxBytes)
-	got = ask("application/json", cut[:proxy.QuestionBodyMaxBytes])
-	wantDisposition(t, got, http.StatusOK, proxy.DispositionAllow)
+	cut := `{"text":"` + strings.Repeat("x", servewaf.QuestionBodyMaxBytes)
+	got = ask("application/json", cut[:servewaf.QuestionBodyMaxBytes])
+	wantDisposition(t, got, http.StatusOK, servewaf.DispositionAllow)
 }
 
 func TestCoreRuleSetAlertNamesTheSite(t *testing.T) {
@@ -1568,7 +1571,7 @@ func TestCoreRuleSetAlertNamesTheSite(t *testing.T) {
 	s := startServeWAF(t, "", map[string]string{wafMode: block})
 
 	got := s.ask(client, sqlInjection)
-	wantDisposition(t, got, http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, got, http.StatusForbidden, servewaf.DispositionDeny)
 
 	waiting := s.queue.Snapshot().Waiting[alerts.DestinationWebhook]
 	if len(waiting) != 1 || waiting[0].Event != alerts.EventWAFBlock ||
@@ -1583,7 +1586,7 @@ func TestReputationHitAlertNamesTheSite(t *testing.T) {
 	s := startServeWAF(t, "", map[string]string{blocklistURLs: dropURL})
 	loadLists(t, s.server, map[string][]string{dropURL: {client}})
 
-	wantDisposition(t, s.ask(client, "/"), http.StatusForbidden, proxy.DispositionDeny)
+	wantDisposition(t, s.ask(client, "/"), http.StatusForbidden, servewaf.DispositionDeny)
 
 	waiting := s.queue.Snapshot().Waiting[alerts.DestinationWebhook]
 	if len(waiting) != 1 || waiting[0].Event != alerts.EventReputationHit ||

internal/servewaf/staticlists_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
@@ -104,6 +104,15 @@ func TestDenyNetsRefuseBeforeTheLookup(t *testing.T) {
 	}
 }
 
+func TestDenyNetsRefusalNamesItsHeuristicAndNetblock(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{denyNets: clientsNet})
+
+	line := s.get(client, http.StatusForbidden, requestlog.ActionDenied)
+	wantHeuristic(t, line, "deny_nets", `{"netblock": "`+clientsNet+`"}`)
+}
+
 func TestRequestRefusedByDenyNetsIsNotCounted(t *testing.T) {
 	t.Parallel()
 

internal/servewaf/trappaths.go

@@ -0,0 +1,39 @@
+package servewaf
+
+// The heuristic trap_paths. It reads SWWAF_TRAP_PATHS.
+
+import (
+	"context"
+	"slices"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+	"sneak.berlin/go/smallwebwaf/internal/rules"
+)
+
+// trapPaths refuses a request for a path in SWWAF_TRAP_PATHS: its path as a
+// path rule sees it, without the query, as sent or once percent-decoded, is one
+// of them. Such a request is a clear sign of attack, as a ban rule's match is:
+// it bans the client's netblock, or in observe mode raises the alert for the
+// ban it would have made. The ban's notes give the path as sent, and so does
+// its figure.
+type trapPaths struct{}
+
+func (trapPaths) name() string { return "trap_paths" }
+
+func (trapPaths) check(_ context.Context, rq *request, now time.Time) *verdict {
+	path := rules.Path(rq.in)
+	if !slices.Contains(rq.h.config.TrapPaths, path) &&
+		!slices.Contains(rq.h.config.TrapPaths, rules.DecodeOnce(path)) {
+		return nil
+	}
+
+	rq.attack = true
+	rq.banForAttack(now, bans.Notes{TrapPath: path})
+
+	return &verdict{
+		action:  requestlog.ActionBanned,
+		figures: map[string]any{"path": path},
+	}
+}

internal/servewaf/trappaths_test.go

@@ -1,4 +1,4 @@
-package proxy_test
+package servewaf_test
 
 import (
 	"net/http"
@@ -83,6 +83,16 @@ func TestTrapPathBansAsABanRuleDoes(t *testing.T) {
 	}
 }
 
+func TestTrapPathRefusalNamesItsHeuristicAndPath(t *testing.T) {
+	t.Parallel()
+
+	s, _, _ := startWithClock(t, "", map[string]string{trapPaths: trapPathList})
+
+	line := s.request(client, "/wp-login.php?redirect_to=x", http.StatusForbidden,
+		requestlog.ActionBanned)
+	wantHeuristic(t, line, "trap_paths", `{"path": "/wp-login.php"}`)
+}
+
 func TestTrapPathMatchesThePathDecodedOnce(t *testing.T) {
 	t.Parallel()
 

internal/smallwebwaf/healthcheck.go

@@ -11,7 +11,7 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/config"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 )
 
 // healthCheckTimeout bounds the whole health check.
@@ -21,11 +21,13 @@ var errHealthEndpoint = errors.New("the health endpoint answered")
 
 // HealthCheck is the container's health check. In servewaf's container, where
 // SMALLWEBWAF_COMMAND is servewaf, it returns 0 while servewaf answers its health
-// endpoint on 127.0.0.1, at the port in SWWAF_LISTEN_ADDR. In any other container
-// it returns 0 while rproxy answers its health endpoint on 127.0.0.1, at the port
-// in SWRP_LISTEN_ADDR, and the app accepts connections at the address in
-// SWRP_UPSTREAM_URL. Otherwise it writes why to stderr and returns 1. It reads no
-// other setting, nor a file that another names, so neither can fail it.
+// endpoint on 127.0.0.1, at the port in SWWAF_LISTEN_ADDR. In rproxy's container,
+// where SMALLWEBWAF_COMMAND is rproxy, unset or empty, it returns 0 while rproxy
+// answers its health endpoint on 127.0.0.1, at the port in SWRP_LISTEN_ADDR, and
+// the app accepts connections at the address in SWRP_UPSTREAM_URL. Otherwise,
+// any other value of SMALLWEBWAF_COMMAND included, it writes why to stderr and
+// returns 1. It reads no other setting, nor a file that another names, so neither
+// can fail it.
 // args are the arguments after `healthcheck`; it takes none, and given
 // one it names it on stderr and returns 1 without checking anything.
 func HealthCheck(
@@ -42,12 +44,17 @@ func HealthCheck(
 	ctx, cancel := context.WithTimeout(ctx, healthCheckTimeout)
 	defer cancel()
 
-	check := checkRProxyAndApp
-	if command, _ := lookupEnv("SMALLWEBWAF_COMMAND"); command == "servewaf" {
-		check = checkServeWAF
+	command, err := config.Command(lookupEnv)
+
+	switch {
+	case err != nil:
+		err = fmt.Errorf("invalid setting: %w", err)
+	case command == "servewaf":
+		err = checkServeWAF(ctx, lookupEnv)
+	default:
+		err = checkRProxyAndApp(ctx, lookupEnv)
 	}
 
-	err := check(ctx, lookupEnv)
 	if err != nil {
 		_, _ = fmt.Fprintln(stderr, "unhealthy:", err)
 
@@ -100,7 +107,7 @@ func checkRProxyAndApp(
 // listenAddr, which the settings have checked has one.
 func askHealthEndpoint(ctx context.Context, listenAddr string) error {
 	_, port, _ := net.SplitHostPort(listenAddr)
-	health := "http://" + net.JoinHostPort("127.0.0.1", port) + proxy.HealthPath
+	health := "http://" + net.JoinHostPort("127.0.0.1", port) + servewaf.HealthPath
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, health, http.NoBody)
 	if err != nil {

internal/smallwebwaf/healthcheck_test.go

@@ -103,8 +103,13 @@ func TestHealthCheckInRProxysContainer(t *testing.T) {
 	}
 
 	wantHealthCheck(t, settings(), 0, "")
+	wantHealthCheck(t, settings(commandSetting, ""), 0, "")
 	wantHealthCheck(t, settings(commandSetting, "rproxy"), 0, "")
 
+	// SMALLWEBWAF_COMMAND cannot be given as a file.
+	wantHealthCheck(t, settings(commandSetting+"_FILE", writeFile(t, "servewaf\n")),
+		0, "")
+
 	// Another setting does not fail it, even an invalid one, and neither does
 	// SWRP_WAF_BACKEND being unset.
 	wantHealthCheck(t, settings("SWRP_TIMEOUT_MS", "soon"), 0, "")
@@ -127,6 +132,14 @@ func TestHealthCheckInRProxysContainer(t *testing.T) {
 	}, 1, "unhealthy: ask rproxy: ")
 }
 
+func TestHealthCheckFailsWithAnyOtherCommand(t *testing.T) {
+	t.Parallel()
+
+	wantHealthCheck(t, map[string]string{commandSetting: "healthcheck"}, 1,
+		"unhealthy: invalid setting: SMALLWEBWAF_COMMAND: "+
+			"\"healthcheck\" is not rproxy or servewaf\n")
+}
+
 func TestHealthCheckRefusesAnArgument(t *testing.T) {
 	t.Parallel()
 

internal/smallwebwaf/rproxy_test.go

@@ -19,7 +19,7 @@ import (
 	"testing"
 	"time"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 	"sneak.berlin/go/smallwebwaf/internal/smallwebwaf"
 )
 
@@ -153,7 +153,7 @@ func TestABanThroughOneSiteRefusesTheClientOnTheOther(t *testing.T) {
 
 	// One request's three lines carry one id, rproxy's with servewaf's answer.
 	line := firstOut.line(t, "path", bannedProbe)
-	if line["disposition"] != proxy.DispositionDeny || line["client_ip"] != placed {
+	if line["disposition"] != servewaf.DispositionDeny || line["client_ip"] != placed {
 		t.Errorf("rproxy's line is %v", line)
 	}
 
@@ -225,7 +225,7 @@ func TestTheSiteAnswersWhileServeWAFIsStoppedAndStartedAgain(t *testing.T) {
 	wantStatus(t, site+"/after-stop", placed, http.StatusOK)
 
 	line := out.line(t, "path", "/after-stop")
-	if line["disposition"] != proxy.DispositionAllow ||
+	if line["disposition"] != servewaf.DispositionAllow ||
 		line["default_disposition"] != true {
 		t.Errorf("rproxy's line is %v", line)
 	}
@@ -318,7 +318,7 @@ func TestAChunkedBodyStaysABodyAtServeWAF(t *testing.T) {
 	const smuggledID = "smuggled-request"
 
 	smuggled := "GET " + bannedProbe + " HTTP/1.1\r\nHost: site.example\r\n" +
-		proxy.ClientHeader + ": " + otherClient + "\r\n" +
+		servewaf.ClientHeader + ": " + otherClient + "\r\n" +
 		"X-Request-ID: " + smuggledID + "\r\n\r\n"
 
 	status := sendRaw(t, site, "POST /upload HTTP/1.1\r\nHost: site.example\r\n"+
@@ -459,10 +459,10 @@ func TestRProxyAsksAServeWAFThatSpeaksHTTP2OverHTTP1(t *testing.T) {
 	protocols := make(chan string, 10)
 	backend := httptest.NewUnstartedServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
-			if r.Header.Get(proxy.ClientHeader) != "" {
+			if r.Header.Get(servewaf.ClientHeader) != "" {
 				protocols <- r.Proto
 
-				w.Header().Set(proxy.DispositionHeader, proxy.DispositionDeny)
+				w.Header().Set(servewaf.DispositionHeader, servewaf.DispositionDeny)
 				w.WriteHeader(http.StatusForbidden)
 			}
 		}))
@@ -532,8 +532,8 @@ func TestRProxyStoppingWaitsForAReportBeingSent(t *testing.T) {
 	release := make(chan struct{})
 	backend := httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
-			if r.Header.Get(proxy.ClientHeader) != "" {
-				w.Header().Set(proxy.DispositionHeader, proxy.DispositionAllow)
+			if r.Header.Get(servewaf.ClientHeader) != "" {
+				w.Header().Set(servewaf.DispositionHeader, servewaf.DispositionAllow)
 
 				return
 			}
@@ -640,7 +640,7 @@ func TestRProxyStoppingCutsOffARequestAfterFiveSeconds(t *testing.T) {
 
 	backend := httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, _ *http.Request) {
-			w.Header().Set(proxy.DispositionHeader, proxy.DispositionAllow)
+			w.Header().Set(servewaf.DispositionHeader, servewaf.DispositionAllow)
 		}))
 	t.Cleanup(backend.Close)
 
@@ -757,7 +757,7 @@ func TestMainRunsRProxy(t *testing.T) {
 	addr, cmd, out := startRProxyProcess(t, wafBackend+"=http://127.0.0.1:9")
 
 	req, err := http.NewRequestWithContext(t.Context(), http.MethodGet,
-		"http://"+addr+proxy.HealthPath, http.NoBody)
+		"http://"+addr+servewaf.HealthPath, http.NoBody)
 	if err != nil {
 		t.Fatalf("new request: %v", err)
 	}

internal/smallwebwaf/servewaf_test.go

@@ -14,7 +14,7 @@ import (
 	"testing"
 	"time"
 
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 	"sneak.berlin/go/smallwebwaf/internal/smallwebwaf"
 )
 
@@ -67,7 +67,7 @@ func TestMainRunsServeWAF(t *testing.T) {
 	})
 
 	addr, _ := out.line(t, "msg", "starting")["address"].(string)
-	ask(t, addr, "/", http.StatusOK, proxy.DispositionAllow)
+	ask(t, addr, "/", http.StatusOK, servewaf.DispositionAllow)
 
 	err = cmd.Process.Signal(syscall.SIGTERM)
 	if err != nil {
@@ -132,7 +132,7 @@ func ask(t *testing.T, addr, path string, status int, disposition string) {
 		t.Fatalf("new request: %v", err)
 	}
 
-	req.Header.Set(proxy.ClientHeader, placed)
+	req.Header.Set(servewaf.ClientHeader, placed)
 	req.Header.Set("X-Request-ID", rand.Text())
 
 	transport := &http.Transport{}
@@ -147,9 +147,9 @@ func ask(t *testing.T, addr, path string, status int, disposition string) {
 	_ = res.Body.Close()
 
 	if res.StatusCode != status ||
-		res.Header.Get(proxy.DispositionHeader) != disposition {
+		res.Header.Get(servewaf.DispositionHeader) != disposition {
 		t.Errorf("answered %d with disposition %q, want %d with %q", res.StatusCode,
-			res.Header.Get(proxy.DispositionHeader), status, disposition)
+			res.Header.Get(servewaf.DispositionHeader), status, disposition)
 	}
 }
 
@@ -193,12 +193,12 @@ func TestServeWAFKeepsItsBansAcrossARestartAndNeedsNoApp(t *testing.T) {
 	}
 
 	runServeWAF(t, env, func(addr string) {
-		ask(t, addr, "/", http.StatusOK, proxy.DispositionAllow)
+		ask(t, addr, "/", http.StatusOK, servewaf.DispositionAllow)
 		// The default rule file bans a probe for this.
-		ask(t, addr, "/.env", http.StatusForbidden, proxy.DispositionDeny)
+		ask(t, addr, "/.env", http.StatusForbidden, servewaf.DispositionDeny)
 	})
 
 	runServeWAF(t, env, func(addr string) {
-		ask(t, addr, "/", http.StatusForbidden, proxy.DispositionDeny)
+		ask(t, addr, "/", http.StatusForbidden, servewaf.DispositionDeny)
 	})
 }

internal/smallwebwaf/smallwebwaf.go

@@ -23,11 +23,11 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/lookup"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
 	"sneak.berlin/go/smallwebwaf/internal/remotelog"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rules"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 	"sneak.berlin/go/smallwebwaf/internal/state"
 )
 
@@ -190,7 +190,7 @@ func RunServeWAF(ctx context.Context, params Params) int {
 func newServer(
 	cfg *config.Config, stdout io.Writer, processLog *slog.Logger,
 	now func() time.Time, ruleFiles *rules.Files, alertQueue *alerts.Queue,
-) (*proxy.Server, error) {
+) (*servewaf.Server, error) {
 	var lookupFile *lookup.File
 
 	if cfg.LookupSource == "file" {
@@ -207,7 +207,7 @@ func newServer(
 		}
 	}
 
-	server := proxy.NewServeWAF(proxy.Params{
+	server := servewaf.New(servewaf.Params{
 		Config:       cfg,
 		RequestLog:   stdout,
 		ProcessLog:   processLog,
@@ -230,7 +230,7 @@ func newServer(
 // loadStateFiles reads the state files into the parts of server and into
 // alertQueue, as state.Load does.
 func loadStateFiles(
-	cfg *config.Config, server *proxy.Server, alertQueue *alerts.Queue,
+	cfg *config.Config, server *servewaf.Server, alertQueue *alerts.Queue,
 	now func() time.Time, processLog *slog.Logger,
 ) (*state.Files, error) {
 	return state.Load(state.Params{
@@ -316,7 +316,7 @@ func startSending(
 // shutdownTimeout to finish, and writes every state file, alerts.json with
 // the alerts still waiting.
 func serve(
-	ctx context.Context, server *proxy.Server, listener net.Listener,
+	ctx context.Context, server *servewaf.Server, listener net.Listener,
 	files *state.Files, ruleFiles *rules.Files, alertQueue *alerts.Queue,
 	processLog *slog.Logger,
 ) int {

internal/smallwebwaf/smallwebwaf_test.go

@@ -20,7 +20,7 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/lookup/lookuptest"
-	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/servewaf"
 	"sneak.berlin/go/smallwebwaf/internal/smallwebwaf"
 )
 
@@ -1225,9 +1225,9 @@ func wantStartingLine(t *testing.T, line map[string]any, dir string) {
 		"SWWAF_ALLOW_NETS":                    "",
 		rateLimitExemptNets:                   "",
 		"SWWAF_DENY_NETS":                     "",
-		"SWWAF_RATE_LIMIT_PER_MINUTE":         "500",
-		"SWWAF_RATE_LIMIT_PER_HOUR":           "20000",
-		rateLimitPerDay:                       "300000",
+		"SWWAF_RATE_LIMIT_PER_MINUTE":         "120",
+		"SWWAF_RATE_LIMIT_PER_HOUR":           "1500",
+		rateLimitPerDay:                       "6000",
 		"SWWAF_RATE_LIMIT_EXEMPT_PATHS":       "",
 		"SWWAF_DENIED_COUNTRIES":              "",
 		"SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES": "",
@@ -1627,7 +1627,7 @@ func statusFrom(t *testing.T, url, from string) int {
 	}
 
 	req.Header.Set("X-Forwarded-For", from)
-	req.Header.Set(proxy.ClientHeader, from)
+	req.Header.Set(servewaf.ClientHeader, from)
 	req.Header.Set("X-Request-ID", rand.Text())
 
 	transport := &http.Transport{}

script/gitea-setup

@@ -0,0 +1,216 @@
+#!/bin/sh
+# script/gitea-setup: build the image, bring up deploy/gitea under a project
+# name of its own, and check it:
+#   - that a page load, a push and a clone sent through traefik pass through
+#     rproxy, and that servewaf checks them;
+#   - that gitea logs the visitor's address, not rproxy's;
+#   - that a request from a container on the shared network skips the checks;
+#   - that with servewaf stopped, gitea still answers through rproxy.
+# It publishes no port of traefik's, since this host's ports 80 and 443 may be
+# taken. It reaches traefik at its address on the shared network instead, so
+# its own requests come from the network's gateway, which servewaf checks like
+# any visitor. Two runs at once on one docker host cannot both start, since
+# both would use the subnet compose.yaml names. The containers, the network,
+# the volumes, the image and the files the script makes are removed however it
+# ends; the gitea and traefik images stay, as the base images of a build do.
+# It needs network access. script/check does not run this.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+# Named after this run, so that runs in other clones on the same host
+# never touch each other's.
+NAME="$("$SCRIPT_DIR/projectname")-gitea-setup-$$"
+IMAGE="$NAME-image"
+NETWORK="${NAME}_shared"
+VISITOR="$NAME-visitor"
+
+# The site's host name and gitea's image, as deploy/gitea/compose.yaml names
+# them. gitea's image also runs the container on the shared network.
+SITE="git.example.org"
+# gitea 1.27.3, 2026-08-29
+GITEA_IMAGE="gitea/gitea@sha256:87a67ee09d3ae0d1df5fda5dcda3e2a1f9236a45b0a59025d6e00e46adc43bef"
+
+# gitea's one user, who owns the repository.
+PASSWORD="owner-password"
+
+# The files the script makes, gitea's secret key for this run, and traefik's
+# and the gateway's addresses on the shared network once the setup runs.
+WORK=""
+secret_key=""
+traefik=""
+gateway=""
+
+cleanup() {
+    # So that a signal cannot stop it partway through.
+    trap '' HUP INT TERM
+    docker rm --force "$VISITOR" >/dev/null 2>&1 || true
+    if [ -n "$WORK" ]; then
+        compose down --volumes --remove-orphans --timeout 5 >/dev/null 2>&1 || true
+        rm -rf "$WORK"
+    fi
+    docker rmi --force "$IMAGE" >/dev/null 2>&1 || true
+}
+
+# compose <argument>...: docker compose on the setup, under this run's project
+# name, with the image built here, this run's secret key and no port of
+# traefik's published.
+compose() {
+    SMALLWEBWAF_IMAGE="$IMAGE" GITEA_SECRET_KEY="$secret_key" \
+        docker compose --project-name "$NAME" \
+        --file "$ROOT/deploy/gitea/compose.yaml" --file "$WORK/no-ports.yaml" "$@"
+}
+
+fail() {
+    echo "gitea-setup: $*; the last lines of each container's output:" >&2
+    compose logs --no-color --tail 30 >&2 || true
+    exit 1
+}
+
+# wait_for <what fails> <command>...: run the command every second until
+# it succeeds, for at most a minute.
+wait_for() {
+    failure="$1"
+    shift
+    tries=0
+    until "$@"; do
+        tries=$((tries + 1))
+        [ "$tries" -lt 60 ] || fail "$failure"
+        sleep 1
+    done
+}
+
+# logged <service> <text>...: a line of the service's output holds every text,
+# in any order.
+logged() {
+    lines="$(compose logs --no-color --no-log-prefix "$1" 2>&1)"
+    shift
+    for text in "$@"; do
+        lines="$(printf '%s\n' "$lines" | grep -F -e "$text")" || return 1
+    done
+}
+
+# send <path> <curl option>...: send a request for path to the site, at
+# traefik's address, and print the status of the answer, 000 for none. traefik
+# answers with a certificate it made itself, since the setup names no
+# certificate resolver.
+send() {
+    path="$1"
+    shift
+    curl --silent --show-error --insecure --max-time 30 --output /dev/null \
+        --write-out '%{http_code}' --resolve "$SITE:443:$traefik" "$@" \
+        "https://$SITE$path" || true
+}
+
+# routed: traefik passes a request for the site's front page on to gitea.
+routed() {
+    [ "$(send / 2>/dev/null)" = 200 ]
+}
+
+# site_git <git argument>...: run git as the owner, without the host's own git
+# settings, reaching the site at traefik's address. git gives up on a transfer
+# slower than 1000 bytes a second for 30 seconds.
+site_git() {
+    GIT_CONFIG_GLOBAL=/dev/null GIT_CONFIG_NOSYSTEM=1 git \
+        -c user.name=owner -c user.email=owner@example.invalid \
+        -c http.sslVerify=false -c "http.curloptResolve=$SITE:443:$traefik" \
+        -c http.lowSpeedLimit=1000 -c http.lowSpeedTime=30 "$@"
+}
+
+# address_of <service>: print the service's address on the shared network.
+address_of() {
+    docker inspect --format "{{(index .NetworkSettings.Networks \"$NETWORK\").IPAddress}}" \
+        "$(compose ps --quiet "$1")"
+}
+
+# passed_through <method> <path>: rproxy passed a request from the gateway for
+# path to gitea on servewaf's allow, and servewaf checked it: its report line
+# gives the client's counts and the Core Rule Set's score.
+passed_through() {
+    wait_for "rproxy logged no $1 $2 that servewaf allowed" logged rproxy \
+        "\"method\":\"$1\"" "\"path\":\"$2\"" "\"client_ip\":\"$gateway\"" \
+        '"disposition":"allow"'
+    wait_for "servewaf logged no check of $1 $2" logged servewaf \
+        '"servewaf_line":"report"' "\"method\":\"$1\"" "\"path\":\"$2\"" \
+        "\"client_ip\":\"$gateway\"" '"action":"forward"' '"counts":' '"waf_score":'
+}
+
+main() {
+    cd "$ROOT"
+    trap cleanup EXIT
+    trap 'exit 1' HUP INT TERM
+    WORK="$(mktemp -d)"
+    printf 'services:\n    traefik:\n        ports: !reset []\n' >"$WORK/no-ports.yaml"
+
+    docker build --no-cache -t "$IMAGE" .
+    secret_key="$(docker run --rm "$GITEA_IMAGE" gitea generate secret SECRET_KEY)"
+
+    # rproxy is healthy once gitea takes connections.
+    compose up --detach --quiet-pull --wait --wait-timeout 120 ||
+        fail "the setup did not start"
+    traefik="$(address_of traefik)"
+    gateway="$(docker network inspect --format '{{(index .IPAM.Config 0).Gateway}}' "$NETWORK")"
+    wait_for "traefik did not route the site to rproxy" routed
+
+    compose exec --user git gitea gitea admin user create --admin \
+        --username owner --password "$PASSWORD" --email owner@example.invalid \
+        --must-change-password=false >/dev/null || fail "creating gitea's user failed"
+    status="$(send /api/v1/user/repos --user "owner:$PASSWORD" \
+        --header "Content-Type: application/json" --data '{"name":"repo"}')"
+    [ "$status" = 201 ] || fail "creating the repository was answered $status"
+
+    status="$(send /owner/repo)"
+    [ "$status" = 200 ] || fail "the repository's page was answered $status"
+    passed_through GET /owner/repo
+    echo "gitea-setup: a page load passes through rproxy, and servewaf checks it"
+
+    wait_for "gitea did not log the visitor's address" logged gitea \
+        "GET /owner/repo for $gateway:"
+    echo "gitea-setup: gitea logs the visitor's address, not rproxy's"
+
+    site_git init --quiet --initial-branch=main "$WORK/repo"
+    echo "hello" >"$WORK/repo/README.md"
+    site_git -C "$WORK/repo" add README.md
+    site_git -C "$WORK/repo" commit --quiet --message "Add a README"
+    site_git -C "$WORK/repo" push --quiet \
+        "https://owner:$PASSWORD@$SITE/owner/repo.git" main ||
+        fail "the push failed"
+    passed_through POST /owner/repo.git/git-receive-pack
+    echo "gitea-setup: a push passes through rproxy, and servewaf checks it"
+
+    site_git clone --quiet "https://owner:$PASSWORD@$SITE/owner/repo.git" \
+        "$WORK/clone" || fail "the clone failed"
+    [ "$(cat "$WORK/clone/README.md")" = hello ] || fail "the clone lacks the README"
+    passed_through POST /owner/repo.git/git-upload-pack
+    echo "gitea-setup: a clone passes through rproxy, and servewaf checks it"
+
+    # A container on the shared network, as sandcastle is, asks for the site
+    # by its name, and so reaches traefik from its own address.
+    status="$(docker run --rm --name "$VISITOR" --network "$NETWORK" \
+        --entrypoint curl "$GITEA_IMAGE" --silent --insecure --max-time 30 \
+        --output /dev/null --write-out '%{http_code}' "https://$SITE/api/v1/version" ||
+        true)"
+    [ "$status" = 200 ] || fail "the request from the shared network was answered $status"
+    wait_for "servewaf logged no request from the shared network" logged servewaf \
+        '"servewaf_line":"report"' '"path":"/api/v1/version"' '"action":"forward"'
+    line="$(compose logs --no-color --no-log-prefix servewaf |
+        grep -F '"servewaf_line":"report"' | grep -F '"path":"/api/v1/version"')"
+    case "$line" in
+        *"\"client_ip\":\"$gateway\""*)
+            fail "the request from the shared network came from the gateway" ;;
+        *'"counts":'* | *'"waf_score":'*)
+            fail "servewaf checked the request from the shared network" ;;
+    esac
+    echo "gitea-setup: a request from the shared network skips the checks"
+
+    compose stop servewaf >/dev/null 2>&1 || fail "servewaf did not stop"
+    status="$(send /owner/repo)"
+    [ "$status" = 200 ] ||
+        fail "with servewaf stopped, the repository's page was answered $status"
+    wait_for "rproxy logged no request SWRP_DEFAULT_DISPOSITION decided" \
+        logged rproxy '"path":"/owner/repo"' '"default_disposition":true'
+    echo "gitea-setup: with servewaf stopped, gitea answers through rproxy"
+}
+
+main "$@"

share/smallwebwaf.run

@@ -3,14 +3,21 @@ set -euo pipefail
 
 # runit's run script for smallwebwaf, run again whenever smallwebwaf
 # exits; the wait spaces out the restarts. SMALLWEBWAF_COMMAND names the
-# command to run: rproxy when it is unset, or servewaf. exec, so that the
-# signal `sv stop` sends reaches smallwebwaf itself.
+# command to run: rproxy when it is unset or empty, or servewaf. With any
+# other value the script starts nothing and stops with a message naming it.
+# exec, so that the signal `sv stop` sends reaches smallwebwaf itself.
 main() {
     sleep 1
     local command="${SMALLWEBWAF_COMMAND:-rproxy}"
-    if [[ "$command" == servewaf ]]; then
-        give_state_dir_to_smallwebwaf
-    fi
+    case "$command" in
+        rproxy) ;;
+        servewaf) give_state_dir_to_smallwebwaf ;;
+        *)
+            printf 'SMALLWEBWAF_COMMAND: "%s" is not rproxy or servewaf\n' \
+                "$command" >&2
+            exit 1
+            ;;
+    esac
     exec chpst -u smallwebwaf:smallwebwaf /usr/local/bin/smallwebwaf "$command"
 }