Last pass: the sixth README review and the fifth SPEC review

The spec names every fault that stops the start, runs step 15 for every request but the health check, and states each of the fourteen repeated requirements once. docs/alerts.md says which alerts have an empty client and netblock and what a summary's detail holds; docs/settings.md lists the settings that need a lookup and points at step 3 for the two static lists. The README and the spec now travel in one branch, so the README never names a spec section that does not exist yet. Model: fable-5-1
README rewritten from scratch so a newcomer can follow it (closes #154 , closes #155 )
2026-10-22 23:02:00 +00:00 · 2026-10-22 22:54:08 +00:00 · 2026-10-22 22:35:29 +00:00 · 2026-10-22 21:51:39 +00:00 · 2026-10-22 21:08:26 +00:00 · 2026-10-22 20:43:32 +00:00
25 changed files with 1857 additions and 2873 deletions
@@ -9,12 +9,11 @@ A web application firewall reads each request on its way to a web app and
 refuses the ones that look like abuse. `smallwebwaf` is also a reverse proxy: it
 accepts requests on the app's behalf, passes them to the app, and passes the
 app's answers back. A request it does not refuse reaches the app as it came,
-apart from a few headers (see "How it sits in front of the app" below).
+apart from a few headers (see "Design" below).

 It needs no setting. Every setting has a default chosen for a service on the
-open internet. The design is in [`SPEC.md`](SPEC.md). The survey of existing
-tools that led to it is in [`EVALUATION.md`](EVALUATION.md). The reference
-documents under [`docs/`](docs/) are listed under "Documents" below.
+open internet. [`SPEC.md`](SPEC.md) says how `smallwebwaf` behaves and why. The
+reference documents under [`docs/`](docs/) are listed under "Documents" below.

 ## What it protects against

@@ -31,9 +30,9 @@ documents under [`docs/`](docs/) are listed under "Documents" below.
  of your own, or an entry in `SWWAF_TRAP_PATHS`, bans those 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 that runs those rules, inspects each
-  request the earlier checks let through. A request the rules take for an attack
-  is refused.
+  common web attacks. Coraza, a Go engine, runs those rules (step 11 under "What
+  happens to a request" below). 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
@@ -53,7 +52,6 @@ For the operator, it:
 - serves Prometheus metrics (see [`docs/metrics.md`](docs/metrics.md));
 - 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/bans.md`](docs/bans.md) and
  [`docs/state-files.md`](docs/state-files.md)).

 Not built, and not planned:
@@ -134,14 +132,243 @@ docker run --detach --name app \

 With no setting, the address of every new visitor is sent to GeoJS, a web
 service, to find its country and network. `SWWAF_LOOKUP_SOURCE=off` sends
-nothing. `SWWAF_LOOKUP_SOURCE=file` looks addresses up in a database file on
-your own host (see [`docs/lookup.md`](docs/lookup.md)).
+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)).

 `deploy/example-app` is such an app. `make example-app` builds it and checks it
 (see "Checking that it works" below). To run `smallwebwaf` outside the image
-while working on it, see "Developing and testing" below.
+while working on it, see "Entrypoints" below.

-## How it sits in front of the app
+## What happens to a request
+
+Two terms recur below. A clear sign of attack is a request that matches a rule
+whose action is `ban`, or asks for a trap path (steps 9 and 10). An offence is a
+request that counts against its client in its history. It is one of:
+
+- a clear sign of attack;
+- a broken limit;
+- a refusal by a rule, by the Core Rule Set or for a missing or wrong token.
+
+`smallwebwaf` handles each request in this order. Once a step refuses a request,
+the steps after it are skipped, apart from step 13. Nothing of a refused request
+reaches the app. "What happens to a request" in [`SPEC.md`](SPEC.md) gives each
+step in full.
+
+1. `GET /_smallwebwaf/healthz` is answered `200` with `ok` at once, before any
+   check and without asking the app.
+2. The client is worked out. A netblock is a range of addresses, written as an
+   address and a prefix length: `203.0.113.0/24`. `SWWAF_TRUSTED_PROXIES` lists
+   the netblocks traefik comes from, by default the private address ranges. For
+   a TCP peer inside them, `X-Forwarded-For` is read from the right, and the
+   first address outside those netblocks is the client. A peer outside them is
+   the client itself. An IPv6 client is its group: the whole netblock around its
+   address, a /64 by default; `SWWAF_IPV6_GROUP_PREFIX` sets its length.
+3. A client in `SWWAF_ALLOW_NETS` skips steps 4 to 11, the byte limits and the
+   error burst, but still needs a token at step 12. A client in
+   `SWWAF_DENY_NETS` is refused.
+4. A client under a ban is refused. If the ban was made for a clear sign of
+   attack, this request makes it permanent.
+5. The client's AS number and country are looked up, unless
+   `SWWAF_LOOKUP_SOURCE` is `off`. An AS number names the network an address
+   belongs to, such as `AS64496`.
+6. The country lists are checked. A client from a country in
+   `SWWAF_DENIED_COUNTRIES` is refused. When
+   `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` is set, a client from any other country
+   is refused, and so is a client without a country. Such a refusal is not an
+   offence.
+7. The reputation sources are checked: the blocklists, the CrowdSec decision
+   list, the DNS blocklists and AbuseIPDB. A client on the CrowdSec decision
+   list is banned until the decision ends. Any other source refuses the client,
+   lowers its limits or only notes it, as `SWWAF_BLOCKLIST_ACTION` and
+   `SWWAF_REPUTATION_ACTION` say. No request waits for a query.
+8. Rate limiting counts the request, unless the client or the path is exempt. A
+   request that takes the client over a limit is refused and bans the client.
+9. A request for a path in `SWWAF_TRAP_PATHS` is refused and bans the client, as
+   a clear sign of attack.
+10. The rule files are checked. A `log` rule notes the match. A `block` rule
+    refuses the request. A `ban` rule refuses it and bans the client, as a clear
+    sign of attack.
+11. The Core Rule Set inspects the request's method, URL and headers, and, once
+    `SWWAF_WAF_BODY_LIMIT` is set, form, JSON and XML bodies. A request it takes
+    for an attack is refused while `SWWAF_WAF_MODE` is `block`, the default, and
+    let through while it is `detect`. It bans no one by itself.
+12. A request under `/_smallwebwaf/` is answered here by `smallwebwaf`, after
+    its token is checked. Any other request is passed to the app. The app's
+    answer is streamed back within the size and time limits.
+13. Once the answer has ended, a request passed to the app has its bytes counted
+    for the byte limits. If a rule, a trap path, the Core Rule Set or a token
+    check refused the request, the refusal is counted for the error burst. The
+    client's history and the anomaly counters are updated. More than
+    `SWWAF_ERROR_BURST_THRESHOLD` refusals of one client in a minute ban it.
+
+In `observe` mode (`SWWAF_MODE=observe`), `smallwebwaf` makes no ban of its own.
+It refuses a request only for a size or time limit, or for a missing or wrong
+token. A request it would otherwise have refused is passed to the app, and its
+log line says what `enforce` mode would have done. Observe mode is for trying a
+configuration before enforcing it.
+
+What a refused visitor sees:
+
+- `SWWAF_BAN_RESPONSE`, by default `403` with the plain text `Forbidden`. It can
+  be `429` instead, or `close`, which closes the connection, so that traefik
+  answers `502`. It answers:
+    - a ban or a broken rate limit;
+    - a `ban` rule or a trap path;
+    - `SWWAF_DENY_NETS` and the country lists;
+    - a reputation source whose action is `deny`.
+- `403` for a `block` rule and the Core Rule Set.
+- For a size or time limit:
+    - `431` for headers over their limit;
+    - `413` for a body over its limit;
+    - `408` for a client too slow to send its body;
+    - `502` or `504` when the app passes a limit or cannot be reached.
+- `401` from an endpoint of `smallwebwaf`'s own, for a request without its
+  token.
+
+## Settings you are likely to touch
+
+Each setting is an environment variable of the app's container, such as
+`docker run -e SWWAF_MODE=observe ...`, read at start.
+[`docs/settings.md`](docs/settings.md) lists every setting, its default and the
+values it takes. The ones most deployments touch:
+
+- `SWWAF_MODE=observe`: log what would have been refused, refuse almost nothing,
+  ban no one. For trying a configuration.
+- `SWWAF_ALLOW_NETS`: netblocks you trust, such as your monitoring. Their
+  clients are refused only for a size or time limit or a missing or wrong token.
+- `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)).
+- `SWWAF_REQUEST_MAX_BYTES`, `SWWAF_CLIENT_REQUEST_TIMEOUT` and
+  `SWWAF_UPSTREAM_REQUEST_TIMEOUT`: raise them for an app that takes uploads
+  over 100 MiB or slower than 60 seconds.
+- `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. Give them as files to keep them from the app.
+- `SWWAF_ALERT_WEBHOOK_URL`, `SWWAF_ALERT_SLACK_WEBHOOK_URL` or
+  `SWWAF_ALERT_NTFY_URL`: where alerts go.
+- `SWWAF_INSTANCE_NAME`: the name in every log line, alert and metric, such as
+  `fsn1app1/gitea`.
+
+## Checking that it works
+
+- `docker inspect --format '{{.State.Health.Status}}' <container>` says
+  `healthy` once `smallwebwaf` answers and the app accepts connections. 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, and its log line
+  has `"action":"forward"`. `https://<site>/_smallwebwaf/healthz` answers `ok`.
+- To see a refusal without banning yourself, run the container with
+  `SWWAF_MODE=observe` and ask for `/.env`. The request reaches the app. Its log
+  line has `"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,
+  `curl -H "Authorization: Bearer $TOKEN" https://<site>/_smallwebwaf/metrics`
+  answers with the metrics.
+- `make example-app` builds the image and the example app on it, runs the app,
+  and checks it. It needs network access. It checks:
+    - the health check;
+    - a request forwarded to the app;
+    - a ban for a broken limit, and a ban for a probe made permanent;
+    - orderly stops with `sv stop` and `docker stop`;
+    - bans surviving a new container on the same volume;
+    - a setting given as a file.
+
+## Entrypoints
+
+This repository adheres to the
+[Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
+standard. The scripts in `script/` are the entrypoints for working on it, and
+the `Makefile` targets are thin shims that call them. The scripts are POSIX sh.
+The tests and the linter run in Docker, as phases of the `Dockerfile`, and never
+on the host.
+
+- `script/bootstrap`: installs on the host what the other scripts need, with
+  `make bootstrap`:
+    - `make`, `git` and `curl`;
+    - Go, for `gofmt`;
+    - node, yarn and prettier.
+- `script/setup`: readies a fresh clone: `script/bootstrap`, then
+  `script/install-precommit`. `make setup`.
+- `script/projectname`: prints `smallwebwaf`, which the other scripts tag their
+  images with.
+- `script/test`: checks that `go.mod` and `go.sum` are tidy, then runs the
+  tests, as the `test` phase of the `Dockerfile`. `make test`.
+- `script/tidy`: writes `go.mod` and `go.sum` as `go mod tidy` writes them, in
+  the `tidy` stage of the `Dockerfile`. `make tidy`.
+- `script/lint`: runs golangci-lint, as the `lint` phase of the `Dockerfile`.
+  `make lint`.
+- `script/fmt`: formats the Go code with `gofmt` and the Markdown with prettier.
+  `make fmt`.
+- `script/fmt-check`: checks the formatting and changes nothing.
+  `make fmt-check`.
+- `script/check`: runs `script/test`, `script/lint` and `script/fmt-check`.
+  `make check`.
+- `script/docker`: builds the image, whose build runs the tests and the linter
+  first. `make docker`.
+- `script/cibuild`: what CI runs: `script/bootstrap`, `script/check`, then the
+  image build.
+- `script/precommit`: run by the git pre-commit hook; runs `script/check`.
+- `script/install-precommit`: installs that hook. `make hooks`.
+- `script/build`: builds `bin/smallwebwaf` with the Go on your host.
+  `make build`.
+- `script/run`: builds `bin/smallwebwaf` and runs it with the settings in your
+  environment, listening on port 8080 in front of an app at
+  `SWWAF_UPSTREAM_URL`. Its state files go in `bin/state` and its rule files are
+  those of `share/rules.d`, unless `SWWAF_STATE_DIR` and `SWWAF_RULES_DIR` say
+  otherwise. `make run`.
+- `script/example-app`: builds the image and the example app on it, runs it with
+  a volume, and checks it as "Checking that it works" above describes. Then it
+  removes the containers, volumes and images. Needs network access.
+  `make example-app`.
+- `script/gitea-requests`: builds the image and runs gitea 1.27.3 behind it at
+  the defaults. It sends through it a sample of gitea's ordinary use and the
+  requests the Core Rule Set is known to refuse, and prints what `smallwebwaf`
+  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 one service 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 several containers, 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;
+- one binary in the app's own container, with no database and no 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
@@ -165,8 +392,8 @@ pinned.
  same `X-Forwarded-Proto`, and `X-Forwarded-For` with traefik's address added
  at the end. The app's TCP peer is `smallwebwaf` on `127.0.0.1`. So the app
  must trust `127.0.0.1` and `::1` for forwarded headers, besides the private
-  address ranges; left at the usual default, it sees every visitor as
-  `127.0.0.1`. Each request also carries its id in `X-Request-ID`. Any
+  address ranges. An app that keeps its usual trusted proxies sees every visitor
+  as `127.0.0.1`. Each request also carries its id in `X-Request-ID`. Any
  `X-Client-ASN` or `X-Client-Country` header a client sent is removed.
 - Both processes start with the container's environment variables. That is why
  every setting of `smallwebwaf` starts with `SWWAF_`. A token given as an
@@ -192,207 +419,31 @@ pinned.

 "Deployment" in [`SPEC.md`](SPEC.md) has the rest: moving `smallwebwaf` to
 another port, the health check's timing, and the forwarded headers.
-
-## What happens to a request
-
-Two terms recur below. A clear sign of attack is a request that matches a rule
-whose action is `ban`, or asks for a trap path (steps 9 and 10). An offence is a
-request that counts against its client in its history. It is one of:
-
- a clear sign of attack;
- a broken limit;
- a refusal by a rule, by the Core Rule Set or for a missing or wrong token.
-
-`smallwebwaf` handles each request in this order. The first step that refuses it
-ends the handling. Nothing of a refused request reaches the app.
-
-1. `GET /_smallwebwaf/healthz` is answered `200` with `ok` at once, before any
-   check and without asking the app.
-2. The client is worked out. A netblock is a range of addresses, written as an
-   address and a prefix length: `203.0.113.0/24`. `SWWAF_TRUSTED_PROXIES` lists
-   the netblocks traefik comes from, by default the private address ranges. For
-   a TCP peer inside them, `X-Forwarded-For` is read from the right, and the
-   first address outside those netblocks is the client. A peer outside them is
-   the client itself. An IPv6 client is its group: the whole netblock around its
-   address, a /64 by default; `SWWAF_IPV6_GROUP_PREFIX` sets its length.
-3. A client in `SWWAF_ALLOW_NETS` skips steps 4 to 11 and the byte limits, but
-   still needs a token at step 12. A client in `SWWAF_DENY_NETS` is refused.
-4. A client under a ban is refused. If the ban was made for a clear sign of
-   attack, this request makes it permanent.
-5. The client's AS number and country are looked up, unless
-   `SWWAF_LOOKUP_SOURCE` is `off`. An AS number names the network an address
-   belongs to, such as `AS64496`.
-6. The country lists are checked. A client from a country in
-   `SWWAF_DENIED_COUNTRIES` is refused. When
-   `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` is set, a client from any other country
-   is refused, and so is a client without a country. Such a refusal is not an
-   offence.
-7. The reputation sources are checked: the blocklists, the CrowdSec decision
-   list, the DNS blocklists and AbuseIPDB. A source the client is on refuses it,
-   lowers its limits, or only notes it, as `SWWAF_BLOCKLIST_ACTION` and
-   `SWWAF_REPUTATION_ACTION` say. No request waits for a query.
-8. Rate limiting counts the request, unless the client or the path is exempt. A
-   request that takes the client over a limit is refused and bans the client.
-9. A request for a path in `SWWAF_TRAP_PATHS` is refused and bans the client, as
-   a clear sign of attack.
-10. The rule files are checked. A `log` rule notes the match. A `block` rule
-    refuses the request. A `ban` rule refuses it and bans the client, as a clear
-    sign of attack.
-11. The Core Rule Set inspects the request's method, URL and headers, and the
-    body too once `SWWAF_WAF_BODY_LIMIT` is set. A request it takes for an
-    attack is refused while `SWWAF_WAF_MODE` is `block`, the default, and let
-    through while it is `detect`. It bans no one by itself.
-12. A request under `/_smallwebwaf/` is answered here by `smallwebwaf`, after
-    its token is checked. Any other request is passed to the app. The app's
-    answer is streamed back within the size and time limits.
-13. Once the answer has ended, the request's bytes are counted for the byte
-    limits, and its refusal, if any, for the error burst. The client's history
-    and the anomaly counters are updated. More than
-    `SWWAF_ERROR_BURST_THRESHOLD` refusals of one client in a minute ban it.
-
-In `observe` mode (`SWWAF_MODE=observe`), `smallwebwaf` makes no ban of its own.
-It refuses a request only for a size or time limit, or for a missing or wrong
-token. A request it would otherwise have refused is passed to the app, and its
-log line says what `enforce` mode would have done. Observe mode is for trying a
-configuration before enforcing it.
-
-What a refused visitor sees:
-
- `SWWAF_BAN_RESPONSE`, by default `403` with the plain text `Forbidden`. It can
-  be `429` instead, or `close`, which closes the connection without an answer.
-  It answers:
-    - a ban or a broken rate limit;
-    - a `ban` rule or a trap path;
-    - `SWWAF_DENY_NETS` and the country lists;
-    - a reputation source whose action is `deny`.
- `403` for a `block` rule and the Core Rule Set.
- `413`, `408`, `504` or `502` for a size or time limit, by which side passed
-  it.
- `401` from an endpoint of `smallwebwaf`'s own, for a request without its
-  token.
-
-## Settings you are likely to touch
-
-Every setting is an environment variable whose name starts with `SWWAF_`. Every
-setting has a default, so none has to be set. Settings are read once, at start;
-to change one, restart the container. A setting set to a value it cannot take
-stops the start with a log line naming the variable and what is wrong.
-[`docs/settings.md`](docs/settings.md) describes every setting, its default and
-the values it takes. The ones most deployments touch:
-
- `SWWAF_MODE=observe`: log what would have been refused, refuse almost nothing,
-  ban no one. For trying a configuration.
- `SWWAF_ALLOW_NETS`: netblocks that skip every check, such as your monitoring.
- `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.
- `SWWAF_REQUEST_MAX_BYTES`, `SWWAF_CLIENT_REQUEST_TIMEOUT` and
-  `SWWAF_UPSTREAM_REQUEST_TIMEOUT`: raise them for an app that takes uploads
-  over 100 MiB or slower than 60 seconds.
- `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. Give them as files to keep them from the app.
- `SWWAF_ALERT_WEBHOOK_URL`, `SWWAF_ALERT_SLACK_WEBHOOK_URL` or
-  `SWWAF_ALERT_NTFY_URL`: where alerts go.
- `SWWAF_INSTANCE_NAME`: the name in every log line, alert and metric, such as
-  `fsn1app1/gitea`.
-
-## Checking that it works
-
- `docker inspect --format '{{.State.Health.Status}}' <container>` says
-  `healthy` once `smallwebwaf` answers and the app accepts connections. 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, and its log line
-  has `"action":"forward"`. `https://<site>/_smallwebwaf/healthz` answers `ok`.
- To see a refusal without banning yourself, run the container with
-  `SWWAF_MODE=observe` and ask for `/.env`. The request reaches the app. Its log
-  line has `"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` or through the
-  ban endpoint (see [`docs/bans.md`](docs/bans.md)).
- With `SWWAF_METRICS_TOKEN` set,
-  `curl -H "Authorization: Bearer $TOKEN" https://<site>/_smallwebwaf/metrics`
-  answers with the metrics.
- `make example-app` builds the image and the example app on it, runs the app,
-  and checks it. It needs network access. It checks:
-    - the health check;
-    - a request forwarded to the app;
-    - a ban for a broken limit, and a ban for a probe made permanent;
-    - orderly stops with `sv stop` and `docker stop`;
-    - bans surviving a new container on the same volume;
-    - a setting given as a file.
-
-## Developing and testing
-
-This repository adheres to the
-[Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
-standard. The scripts in `script/` are the entrypoints for working on it, and
-the `Makefile` targets are thin shims that call them. The tests and the linter
-run in Docker, as phases of the `Dockerfile`, and never on the host.
-
- `make bootstrap`: installs what the other scripts need on the host: `make`,
-  `git` and `curl`; Go, for `gofmt`; node, yarn and prettier. `make setup` also
-  installs the git pre-commit hook, which runs `make check`.
- `make check`: `make test` (tidy `go.mod` and `go.sum`, then the tests),
-  `make lint` (golangci-lint) and `make fmt-check`. `make fmt` formats the Go
-  code with `gofmt` and the Markdown with prettier.
- `make docker`: builds the image, whose build runs the tests and the linter
-  first. `make tidy` rewrites `go.mod` and `go.sum` in the image's `tidy` stage.
- `make build`: builds `bin/smallwebwaf` with the Go on your host. `make run`
-  builds it and runs it with the settings in your environment, listening on port
-  8080 in front of an app at `SWWAF_UPSTREAM_URL`. Its state files go in
-  `bin/state` and its rule files are those of `share/rules.d`, unless
-  `SWWAF_STATE_DIR` and `SWWAF_RULES_DIR` say otherwise.
- `make example-app`: builds and checks the example app, then removes the
-  containers, volumes and images it made. Needs network access.
- `make gitea-requests`: builds the image and runs gitea 1.27.3 behind it at the
-  defaults. It sends through it a sample of gitea's ordinary use and the
-  requests the Core Rule Set is known to refuse, and prints what `smallwebwaf`
-  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.
- `script/cibuild`: what CI runs: `script/bootstrap`, `script/check`, then the
-  image build.
-
 "Architecture" in [`SPEC.md`](SPEC.md) lists the packages and what each does.

 ## TODO

- Everything `SPEC.md` describes is built.
- Two points `SPEC.md` defers until there is experience to go on: sharing bans
-  between the instances of several apps, and sending the log over RELP.
+- Planned, as "Planned, not built" in [`SPEC.md`](SPEC.md) describes:
+    - sharing bans between the instances of several apps;
+    - sending the log over RELP.

 ## Documents

- [`SPEC.md`](SPEC.md): the design.
+- [`SPEC.md`](SPEC.md): how `smallwebwaf` behaves, and why.
 - [`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/bans.md`](docs/bans.md): how bans are made, how long they last, and how
-  to lift or make one.
- [`docs/rules.md`](docs/rules.md): the rule files.
- [`docs/core-rule-set.md`](docs/core-rule-set.md): what the Core Rule Set
-  inspects and how it scores a request.
+- [`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/`.
- [`docs/request-log.md`](docs/request-log.md): the request log's fields, and
-  sending the log to a syslog server.
- [`docs/alerts.md`](docs/alerts.md): the alert events, their contents and
-  destinations.
+  `/_smallwebwaf/`, with examples.
+- [`docs/request-log.md`](docs/request-log.md): the request log's fields.
+- [`docs/alerts.md`](docs/alerts.md): the alert events and what each destination
+  gets.
 - [`docs/metrics.md`](docs/metrics.md): the metrics.
- [`docs/state-files.md`](docs/state-files.md): the state files and editing
-  them.
- [`docs/lookup.md`](docs/lookup.md): GeoJS and the lookup database.
- [`docs/reputation.md`](docs/reputation.md): blocklists, DNS blocklists,
-  AbuseIPDB and CrowdSec.
+- [`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.

@@ -1,26 +1,20 @@
 # Admin endpoints

-`smallwebwaf` answers these requests itself, on the app's own address and
-through traefik like any other request. Apart from the health check, each needs
-a token, sent as `Authorization: Bearer <token>`, and goes through every check
-any other request goes through. It is answered where another request would be
-passed to the app: a banned client stays refused, and each request counts toward
-rate limiting. A missing or wrong token is answered `401`, in `observe` mode
-too. Such a refusal counts toward the error burst, so a client guessing tokens
-is soon banned. While a token is unset, its endpoints answer `404`.
+The endpoints under `/_smallwebwaf/`, what each takes and what each answers.
+"Admin endpoints" in [`SPEC.md`](../SPEC.md) says which checks they go through
+and how their tokens work.

- `GET /_smallwebwaf/healthz`: `200` and `ok`, to anyone, before any check and
-  without asking the app.
+- `GET /_smallwebwaf/healthz`: `200` and `ok`, to anyone.
 - `GET /_smallwebwaf/metrics`: the metrics, for `SWWAF_METRICS_TOKEN` (see
  [`metrics.md`](metrics.md)).
 - `GET /_smallwebwaf/bans`: every ban held, under `bans`, each as `bans.json`
  lists it. Needs `SWWAF_ADMIN_TOKEN`, as do the three below.
 - `POST /_smallwebwaf/bans`: bans a netblock. The body is a JSON object of
  `netblock`, `duration` and, if you like, `reason`. `netblock` is a netblock
-  such as `203.0.113.0/24`, or a client's address. A client's address bans its
-  IPv4 netblock (`SWWAF_BAN_SCOPE_V4_PREFIX`) or its IPv6 group. `duration` is a
-  duration such as `1h` or `7d`, or `permanent`. The ban starts at once, with
-  the cause `admin`. A bad body is answered `400`, saying what is wrong:
+  such as `203.0.113.0/24`, or a client's address, which bans its IPv4 netblock
+  (`SWWAF_BAN_SCOPE_V4_PREFIX`) or its IPv6 group. `duration` is a duration such
+  as `1h` or `7d`, or `permanent`. A bad body is answered `400`, saying what is
+  wrong:
    - one that is not such an object, or has another field;
    - one longer than 4 KiB;
    - one that names an IPv4-mapped netblock, or an address with a zone.
@@ -28,8 +22,27 @@ is soon banned. While a token is unset, its endpoints answer `404`.
  address `<client>`. It answers `404` when none is active.
 - `GET /_smallwebwaf/clients/<ip>`: what `smallwebwaf` knows of the client.
  Under `client`, its counters and history as `clients.json` holds them, or
-  `null` when it has never been seen. Under `bans`, every ban covering the
-  address, with its notes.
+  `null` when `clients.json` does not hold it. Under `bans`, every ban covering
+  the address, with its notes.

-An admin whose own address is banned lifts that ban by editing `bans.json` (see
-[`bans.md`](bans.md)).
+## Examples
+
+With `SWWAF_ADMIN_TOKEN` set, and the token in `$TOKEN`:
+
+```sh
+# Every ban.
+curl -H "Authorization: Bearer $TOKEN" https://app.example/_smallwebwaf/bans
+
+# Ban 203.0.113.0/24 for seven days.
+curl -H "Authorization: Bearer $TOKEN" \
+    --json '{"netblock": "203.0.113.0/24", "duration": "7d", "reason": "probes for logins"}' \
+    https://app.example/_smallwebwaf/bans
+
+# Lift the bans on 203.0.113.9.
+curl -H "Authorization: Bearer $TOKEN" -X DELETE \
+    https://app.example/_smallwebwaf/bans/203.0.113.9
+
+# What smallwebwaf knows of 203.0.113.9.
+curl -H "Authorization: Bearer $TOKEN" \
+    https://app.example/_smallwebwaf/clients/203.0.113.9
+```
@@ -1,17 +1,17 @@
 # Alerts

-Each alert goes to each destination you name. `SWWAF_ALERT_WEBHOOK_URL` gets it
-as one JSON object. `SWWAF_ALERT_SLACK_WEBHOOK_URL` and `SWWAF_ALERT_NTFY_URL`
-get a message made from it. The settings are under "Alert destinations" in
-[`settings.md`](settings.md). An alert is one of these events, and is sent when
-its event is in `SWWAF_ALERT_EVENTS`:
+The alert events, the JSON object the webhook gets, and the messages Slack and
+ntfy get. "Alerting" in [`SPEC.md`](../SPEC.md) says when an alert is sent, held
+back or dropped.
+
+## Events

 - `ban`: a ban `smallwebwaf` made.
 - `permanent_ban`: a permanent ban it made, or an existing ban made permanent by
  a request.
- `waf_block`: the Core Rule Set scored a request at or over the threshold. In
-  `block` mode the request was refused. In `detect` mode it was not, and the
-  alert's `detail` gives `mode`.
+- `waf_block`: the Core Rule Set scored a request at or over the threshold. The
+  request was refused unless the alert's `detail` gives `mode`: `detect` or
+  `observe`.
 - `anomaly`: a count over an anomaly threshold.
 - `reputation_hit`: a request from a client on a blocklist, the CrowdSec
  decision list or a DNS blocklist, or with an AbuseIPDB score that is a hit.
@@ -25,12 +25,7 @@ its event is in `SWWAF_ALERT_EVENTS`:
    - a rule file or state file edit with an error;
    - a state file that cannot be written;
    - a replacement lookup database that cannot be read.
- `summary`: the hourly summary described under "Repeats and the hourly cap"
-  below.
-
-The bans you make raise no alert. In `observe` mode, a request that would have
-made a ban still raises the ban's alert, with `mode` set to `observe` in its
-`detail`.
+- `summary`: the hourly summary of alerts held back.

 ## The JSON object

@@ -81,24 +76,32 @@ on one line:
 }
 ```

- `instance` is `SWWAF_INSTANCE_NAME`. `time` is when the alert was raised.
-  `event` is one of the events above.
- `client` is the address whose request raised the alert. `netblock` is the
-  ban's netblock, the netblock an anomaly counted, or the client's group. Both
-  are empty for `source_failure` and `file_error`. `asn`, `as_name` and
-  `country` are the client's as known when the alert was raised. They are empty
-  when GeoJS had not answered yet.
- `reason` is a short sentence, such as
+- `instance`: `SWWAF_INSTANCE_NAME`. `time`: when the alert was raised. `event`:
+  one of the events above.
+- `client`: the address whose request raised the alert. Empty for
+  `source_failure`, `file_error` and `summary`.
+- `netblock`: empty for `source_failure`, `file_error` and `summary`; otherwise
+  one of:
+    - the ban's netblock;
+    - the netblock an anomaly counted, empty in the `asn` and `total` scopes;
+    - for the other events, the client as rate limiting counts it: an IPv4
+      address as a /32, or an IPv6 group.
+- `asn`, `as_name` and `country`: the client's, as known when the alert was
+  raised. They are empty when GeoJS had not answered yet.
+- `reason`: a short sentence, such as
  `requests per minute over the limit of 1000` or `listed by a blocklist`.
- `detail` is what is particular to the event:
-    - for a ban, its `cause`, `ban_expires` and `notes` (see
-      [`bans.md`](bans.md) for the notes);
+- `detail`: what is particular to the event:
+    - for a ban, its `cause`, `ban_expires` and `notes` (the notes are listed
+      under `bans.json` in [`state-files.md`](state-files.md));
    - for an anomaly, the `scope`, `window`, `kind`, `count` and `threshold`;
    - for a reputation hit, the `source` and, for AbuseIPDB, the `score`;
    - for a Core Rule Set match, the `rule_ids`, `score`, `method` and `path`;
    - for a source failure, the `source` and `error`;
-    - for a file error, the `file` and `error`.
- `suppressed_repeats` is how many repeats the cooldown held back before this
+    - for a file error, the `file` and `error`;
+    - for a summary, the `hour` it covers, the `count` of alerts held back, and
+      that count by event in `events`;
+    - `mode`, when the request was not refused: `detect` or `observe`.
+- `suppressed_repeats`: how many repeats the cooldown held back before this
  alert.

 ## Slack and ntfy
@@ -128,22 +131,3 @@ The priority and tag by event:
 - `reputation_hit`: priority `low`, tag `label`.
 - `source_failure` and `file_error`: priority `high`, tag `warning`.
 - `summary`: priority `default`, tag `bar_chart`.
-
-## Repeats and the hourly cap
-
-A repeat is an alert for the same event on the same netblock, source, file or
-thing counted, less than `SWWAF_ALERT_COOLDOWN` after the last. It is held back
-and counted, and the next alert sent gives the count. Past
-`SWWAF_ALERT_MAX_PER_HOUR` alerts in an hour, the rest are held back and counted
-by event. Once the hour ends, one alert with the event `summary` gives those
-counts. It also counts the repeats that a cooldown held back and that no later
-alert reported.
-
-## Sending
-
-Each destination has a queue of at most 1000 alerts, sent one at a time, so a
-slow destination holds up nothing. A `2xx` answer takes an alert. A `4xx` other
-than `408` and `429` refuses it, and it is dropped. Anything else is a failure:
-the alert is sent again a second later, and twice as long after each further
-failure, up to a minute. `alerts.json` keeps the queues and cooldowns across a
-restart (see [`state-files.md`](state-files.md)).
@@ -1,84 +0,0 @@
-# Bans
-
-How bans are made, what they cover and how long they last is under "Bans" in
-[`SPEC.md`](../SPEC.md); the settings are under "How long bans last and what
-they cover" in [`settings.md`](settings.md). This file says what a ban's notes
-hold, and how to make, keep or lift a ban.
-
-## The notes
-
-Each ban carries notes for deciding whether to lift it, drawn from what
-`smallwebwaf` already knows. Nothing is looked up to fill them:
-
- the AS number, AS name and country, added when the lookup answers (empty when
-  lookups are off);
- what was broken: the rule id and target that matched, or the trap path, or the
-  limit, its window and the count reached;
- the client's percentage of the limit, with the setting that gave it;
- the reputation sources the client is on;
- the request that caused the ban: time, method, host, path with its query
-  string, status and user agent, each text cut to 256 bytes;
- the netblock's requests since it was first seen, and how many this ban has
-  refused so far, kept up to date while the ban lasts;
- how many earlier bans the netblock had, by cause.
-
-## Managing bans by editing `bans.json`
-
-`bans.json` in the state directory holds every ban, indented to be read. A
-permanent ban's `expires` is `null`. `smallwebwaf` watches the file and takes in
-an edit as soon as it is saved (see [`state-files.md`](state-files.md)).
-
-To ban a netblock, add an entry with its `netblock`, `start` and `expires`.
-`expires` is `null` for a ban that never ends. `reason`, `notes` and `cause` may
-be left out; the cause is then `admin`:
-
-```json
-{
-    "version": 1,
-    "bans": [
-        {
-            "netblock": "203.0.113.0/24",
-            "start": "2026-10-06T12:00:00Z",
-            "expires": null,
-            "reason": "probes for logins"
-        }
-    ]
-}
-```
-
-To keep a ban `smallwebwaf` made, so that it is never dropped, set its `cause`
-to `admin`. To lift a ban, add `"lifted"` with the time you lift it, such as
-`"lifted": "2026-10-06T13:00:00Z"`. The ban then refuses nothing and does not
-make the netblock's next ban longer. It is kept with its notes. To forget a ban,
-delete its entry. A ban whose cause is `attack` becomes permanent at the first
-request it refuses. One whose cause is `admin` or `crowdsec` does not.
-
-An edit that cannot be read does not stop the running `smallwebwaf`. It keeps
-what it holds. At the file's next write it renames your file to `bans.json.bad`,
-writes the file again from memory, and logs and alerts the error. Mend the
-`.bad` file and move it back.
-
-## Managing bans through the admin endpoints
-
-With `SWWAF_ADMIN_TOKEN` set, and the token in `$TOKEN`:
-
-```sh
-# Every ban.
-curl -H "Authorization: Bearer $TOKEN" https://app.example/_smallwebwaf/bans
-
-# Ban 203.0.113.0/24 for seven days.
-curl -H "Authorization: Bearer $TOKEN" \
-    --json '{"netblock": "203.0.113.0/24", "duration": "7d", "reason": "probes for logins"}' \
-    https://app.example/_smallwebwaf/bans
-
-# Lift the bans on 203.0.113.9.
-curl -H "Authorization: Bearer $TOKEN" -X DELETE \
-    https://app.example/_smallwebwaf/bans/203.0.113.9
-
-# What smallwebwaf knows of 203.0.113.9.
-curl -H "Authorization: Bearer $TOKEN" \
-    https://app.example/_smallwebwaf/clients/203.0.113.9
-```
-
-See [`admin-endpoints.md`](admin-endpoints.md) for what each answers. An admin
-whose own address is banned lifts that ban by editing `bans.json`.
@@ -1,31 +0,0 @@
-# The Core Rule Set
-
-The OWASP Core Rule Set 4.25.0 runs on each request after the rule files, unless
-`SWWAF_WAF_MODE` is `off`. It reads the method, the URL with its query, and the
-headers. Once `SWWAF_WAF_BODY_LIMIT` is set, it also reads a body that is form
-data, multipart, JSON or XML. No answer is inspected. The settings are under
-"Attack detection" in [`settings.md`](settings.md). The same section of
-[`SPEC.md`](../SPEC.md) says why bodies are not read by default, and gives the
-six changes `smallwebwaf` makes to the Core Rule Set, with the reason for each.
-
-Each rule that matches adds to the request's score. A score at or over
-`SWWAF_WAF_ANOMALY_THRESHOLD` is a match. A match is refused with `403` while
-`SWWAF_WAF_MODE` is `block`, and let through while it is `detect`. Either way
-the log line gives the rule ids and the score, and a `waf_block` alert is sent.
-A request with more than 1000 query parameters or body fields adds 5 to its
-score, since Coraza reads only the first 1000. The Core Rule Set inspects only a
-request that every earlier check let through. It skips a path under
-`SWWAF_WAF_EXEMPT_PATHS` and a client in `SWWAF_ALLOW_NETS`. An engine error on
-a request forwards the request, and is logged and counted.
-
-Body inspection suits apps whose forms carry no code. In front of a code forge
-it refuses issue and comment text, wiki pages and files saved in the web editor
-that hold shell commands or code. The log line names the rule ids, which
-`SWWAF_WAF_DISABLED_RULES` can switch off. A body the Core Rule Set cannot parse
-adds 5 to the score. So does a multipart body cut by the limit in the middle of
-a part's header. The client has until `SWWAF_CLIENT_REQUEST_TIMEOUT` runs out to
-send the part that is read. Any other body, such as a git push, reaches the app
-uninspected.
-
-[`gitea.md`](gitea.md) records what the Core Rule Set still refuses in front of
-gitea, with and without body inspection.
@@ -13,16 +13,19 @@ checked again when gitea or the Core Rule Set changes version.
  by it.
 - A clone is a response. It fits the defaults of 30 minutes and 5 GiB for all
  but the largest repositories and slowest links.
- A push is a request, and so is every other upload: a git push, an LFS object,
-  a container image layer, a package file or a release attachment. At the
-  defaults, an upload larger than 100 MiB or taking more than 60 seconds is cut
-  off. The client is answered `413` for a body that is too large, before
-  anything reaches gitea when the request announces its size. It is answered
-  `408` for a body it sends too slowly, or `504` if gitea is too slow to take
-  it. The upload fails, and no one is banned for it. A gitea that takes large
-  uploads needs `SWWAF_REQUEST_MAX_BYTES`, `SWWAF_CLIENT_REQUEST_TIMEOUT` and
-  `SWWAF_UPSTREAM_REQUEST_TIMEOUT` raised to fit. The Core Rule Set does not
-  read an upload's body, which streams through without being held in memory.
+- 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.
+
+    At the defaults, an upload larger than 100 MiB or taking more than 60
+    seconds is cut off ("Size and time limits" in `SPEC.md`). A gitea that takes
+    large uploads needs `SWWAF_REQUEST_MAX_BYTES`,
+    `SWWAF_CLIENT_REQUEST_TIMEOUT` and `SWWAF_UPSTREAM_REQUEST_TIMEOUT` 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
@@ -32,8 +35,7 @@ checked again when gitea or the Core Rule Set changes version.
  jobs. It is then banned, the job it is running fails, and each repeat within a
  day makes the ban longer. Newer runners ask less often, but a busy one, or
  several on one address, can still pass it. Put the runners' addresses in
-  `SWWAF_RATE_LIMIT_EXEMPT_NETS`. That takes them out of the request and byte
-  limits, while the error burst, attack detection and bans still apply.
+  `SWWAF_RATE_LIMIT_EXEMPT_NETS`.

 ## What the Core Rule Set lets through

@@ -55,22 +57,21 @@ the refusals in the next section:

 ## What the Core Rule Set still refuses

-Each refusal answers only that request, with `403`, and bans no one by itself.
-It counts toward the error burst, which a person does not reach this way. The
-request log names the rule in `waf_rule_ids`, which `SWWAF_WAF_DISABLED_RULES`
-can switch off.
+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. Every query parameter is checked against the Core
-Rule Set's lists of system files and commands, except the ten named under
-"Attack detection" in `SPEC.md`. A release attachment uploaded through the API
-as `docker-compose.yml` is refused the same way. Examples:
+Most often this is a search. A search term is a query parameter, which the Core
+Rule Set checks against its lists of system files and commands (see the fourth
+change under "Attack detection" in `SPEC.md`). A release attachment uploaded
+through the API as `docker-compose.yml` is refused the same way. Examples:

 - a name on those lists, such as `package.json`, `.gitignore` or
  `docker-compose.yml`;
- text that starts with a command name, or whose first word has one right after
-  a `/`, such as `python3`, `ssh key` or `feat/docker-support`;
+- text that starts with a command name, such as `python3` or `ssh key`, or has
+  one right after a `/` in its first word, such as `feat/docker-support`;
 - a shell command with its options or a system path (`ls -la`, `sed -i`,
  `/bin/sh`), or a command in backticks;
 - script code (`fetch(`, `${VAR}`, `process.env`), HTML (`<img src=`) or an SQL
@@ -80,15 +81,15 @@ as `docker-compose.yml` is refused the same way. Examples:
 ### A branch, tag or file name that starts with a command name

 The Core Rule Set's list of commands (932260) holds names such as `docker-`,
-`python3`, `ansible`, `base64` and `whoami`. A branch, tag or file name that
-starts with one is refused. So is one that has such a name right after a `/`,
-such as `feat/docker-support`, `fix/docker-build` or
+`python3`, `ansible`, `base64` and `whoami`. A query parameter holding a branch,
+tag or file name that starts with one is refused. So is one that has such a name
+right after a `/`, such as `feat/docker-support`, `fix/docker-build` or
 `renovate/docker-build-push-action-6.x`. gitea's own pages send the name in a
 query parameter that 930120, 932160 and 932260 still check:

- `refSubUrl`, the branch or tag of a directory listing. It is sent when the
-  listing asks for its entries' last commits in a second request, which it does
-  whenever gitea takes more than a second to work them out;
+- `refSubUrl`, the branch or tag of a directory listing. A listing sends it when
+  it asks for its entries' last commits in a second request. It does so whenever
+  gitea takes more than a second to work them out;
 - `name`, when a branch is deleted or restored on the branches page;
 - `tag`, when a release is started from a tag;
 - `template`, the file of an issue template, when an issue is opened from it;
@@ -109,9 +110,9 @@ What a visitor sees, for a branch named `docker-build`:
 ### A file name in a query parameter that trips the code rules

 The Core Rule Set's rules for Java, script, PowerShell and SQL find what they
-look for in some file names. This holds in the parameters `smallwebwaf` leaves
-out of 930120, 932160 and 932260 too (see the changes to the Core Rule Set under
-"Attack detection" in `SPEC.md`). Examples:
+look for in some file names. This holds too in the ten query parameters that
+930120, 932160 and 932260 do not check (see the fourth change under "Attack
+detection" in `SPEC.md`). Examples:

 - `runtime` in OpenJDK's `src/java.base/share/classes/java/lang/Runtime.java`
  (944110);
@@ -128,9 +129,9 @@ For such a file, these requests are refused:
 - the API's call for the contents of files that names it in its query (`body`);
 - the commit graph of that file alone (`file`);
 - the hidden lines of its diff (`path`), which stay hidden;
- the sign-in page gitea sends a visitor to on the way to a page of the file
-  that needs signing in, such as its edit page (`redirect_to`). The visitor can
-  still sign in by opening the sign-in page itself.
+- the sign-in page, for a visitor who opens a page of the file that needs
+  signing in, such as its edit page (`redirect_to`). The visitor can still sign
+  in by opening the sign-in page itself.

 ### A path

@@ -142,25 +143,30 @@ For such a file, these requests are refused:
  `process.env.d.ts` does.
 - A path with a directory named `...` (930100, 930110), such as `.../notes.txt`.

-For such a file, the page of the file, its raw file, its history, its blame and
-its edit page are refused. The directory that holds it lists it, and a clone
-carries it.
+For such a file, these are refused:
+
+- the page of the file;
+- its raw file;
+- its history and its blame;
+- its edit page.
+
+The directory that holds it lists it, and a clone carries it.

 ### A container image push that reuses a layer

 A push can reuse a layer of an image docker has pushed to that gitea before.
 docker then asks gitea to take the layer from that image, naming it in the query
 parameter `from`, which 932260 checks. The request is refused when the image's
-owner, or its name after the owner, starts with an entry on the list of
-commands. Examples are `owner/python3-app`, `owner/docker-base`, and any image
-of an owner named `ansible` or `docker-team`.
+owner starts with an entry on the list of commands. It is refused too when the
+image's name after the owner starts with one. Examples are `owner/python3-app`,
+`owner/docker-base`, and any image of an owner named `ansible` or `docker-team`.

 What happens next depends on docker's image store. A docker that keeps its
 images in containerd's image store fails the push, and fails each new try the
 same way. A new install of Docker Engine 29 does this. A docker that keeps them
 in its own older image store uploads the layer instead. The push then succeeds
 after one refusal for each layer it reuses, and each of those refusals counts
-toward the error burst.
+toward the error burst ("Attack detection" in `SPEC.md`).

 ### Artifact uploads from `actions/upload-artifact@v3`

@@ -168,9 +174,9 @@ This action sends the header `Content-Range`, which the Core Rule Set refuses
 (920450). The action sends two files at a time, does not retry a `403`, and
 sends no further file once one is refused. So an upload is refused once or
 twice, however many files it holds, and the step fails. One upload does not ban
-the runner. More than 30 such refusals from its address within a minute, as when
-many jobs upload at once, ban it through the error burst.
-`actions/upload-artifact@v4` does not send the header.
+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

@@ -192,8 +198,7 @@ Of the requests above, the script sends:
  code rules", the API's list of its commits;
 - for `Runtime.java` alone, the commit graph of that file, the hidden lines of
  its diff, and the API's call for the contents of files that names it;
- the sign-in page gitea sends a visitor to on the way to the edit page of
-  `document.write.js`;
+- the sign-in page for a visitor who opens the edit page of `document.write.js`;
 - the pages of `java.lang.String.md`,
  `META-INF/services/org.apache.commons.logging.LogFactory`, `process.env.d.ts`
  and `.../notes.txt`;
@@ -1,56 +1,37 @@
 # What the image holds

-The `smallwebwaf` image is the base of each app's own image. The requirements
-are under "Deployment" in [`SPEC.md`](../SPEC.md); this file lists what the
-image holds, how each part is pinned, and why.
+The contents of the `smallwebwaf` image, and how each part is pinned.
+"Deployment" in [`SPEC.md`](../SPEC.md) says why each part is there and why it
+is pinned that way.

 ## Contents

- Ubuntu 26.04 LTS, the newest long-term support release of Ubuntu, pinned by
-  digest. The image moves to the next LTS release when that ships.
- `ca-certificates`, `nix-bin` and `runit` from Ubuntu, installed from a dated
-  snapshot of its archive and checked by hash. The Ubuntu image has no CA
-  certificates; without them Nix cannot download packages and `smallwebwaf`
-  cannot reach GeoJS.
- Nix and nixpkgs, fixed at one release. Root uses Nix directly; no Nix daemon
-  runs. `nix-bin` creates no build users, so `build-users-group =` in
-  `/etc/nix/nix.conf` lets root build without them.
- runit, and `runsvinit` as the entrypoint, as the owner's code style guide asks
-  for service containers. No package carries `runsvinit`, so the image builds it
-  from its archived source (`github.com/peterbourgon/runsvinit`, unchanged
-  since 2015) at a fixed commit hash, with a `go.mod` the build writes.
-  `runsvinit` starts runit's `runsvdir`, which runs the `run` script of each
-  directory under `/etc/service` and runs it again whenever it exits. Ubuntu's
-  `sv` looks for services there too.
- The `smallwebwaf` binary, and a user of its own, `smallwebwaf` (uid and gid
-  65532).
- The service directory `/etc/service/smallwebwaf`. Its `run` script waits one
-  second (`sleep 1`), makes `SWWAF_STATE_DIR` and every file in it belong to the
-  `smallwebwaf` user, and starts `smallwebwaf` as that user with runit's
-  `chpst`.
- The directory `/var/lib/smallwebwaf` for the state files, and
-  `/etc/smallwebwaf/rules.d` with the default rule file.
- Port 8080 declared (`EXPOSE 8080`), and the health check (`HEALTHCHECK`) that
-  "The health check" in `SPEC.md` describes.
+- Ubuntu 26.04 LTS, pinned by digest.
+- `ca-certificates`, `nix-bin` and `runit` from Ubuntu, from the snapshot of its
+  archive at `20261001T000000Z`.
+- 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`.
+  Unpacked, nixpkgs takes about 500 MiB.
+- `runsvinit` as the entrypoint, built from `github.com/peterbourgon/runsvinit`
+  at a fixed commit hash.
+- The `smallwebwaf` binary, and the user `smallwebwaf` (uid and gid 65532).
+- The service directory `/etc/service/smallwebwaf`, with the `run` script
+  `share/smallwebwaf.run`.
+- `/var/lib/smallwebwaf` for the state files, and `/etc/smallwebwaf/rules.d`
+  with the default rule file `share/rules.d/00-default.rules`.
+- `EXPOSE 8080`, and the `HEALTHCHECK` that runs `smallwebwaf healthcheck`.

-## Pinning
+## Pins

- Ubuntu's packages come from Ubuntu's snapshot service, the archive as it was
-  at the moment the Dockerfile names (`--snapshot 20261001T000000Z`), never
-  earlier than the pinned Ubuntu image's date. The Dockerfile names the SHA-256
-  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
-  hashes are the amd64 archive's, so the image is built for amd64 only. The
-  snapshot is fetched over HTTPS with the CA certificates of the Go image that
-  builds `smallwebwaf`, itself pinned by digest, since the Ubuntu image has
-  none.
- nixpkgs comes from a release file on `releases.nixos.org` (`nixexprs.tar.xz`
-  of `nixos-26.05.11045.774debe7a0d1`), named with its SHA-256 hash, not from a
-  GitHub archive, whose bytes can change. It is set up for root as `nixpkgs`.
-  Root's Nix profile, `/nix/var/nix/profiles/default/bin`, is last on the
-  `PATH`, so that no package hides the image's own commands; busybox's `sv`, for
-  one, looks for services elsewhere. Unpacked, nixpkgs takes about 500 MiB.
- An app built on the image gets the same packages each time it is built.
-  Security fixes from Ubuntu and nixpkgs come with a newer `smallwebwaf` image,
-  which an app takes by changing the digest in its `FROM` line. The image moves
-  to each new nixpkgs release, every six months.
+- 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.
+- nixpkgs: the release file `nixexprs.tar.xz` of
+  `nixos-26.05.11045.774debe7a0d1` on `releases.nixos.org`, named with its
+  SHA-256 hash.
+- `runsvinit`: the archived repository, unchanged since 2015, at its last commit
+  (`b4b2c78`, eight commits after `v2.0.0`), by commit hash, with a `go.mod` the
+  build writes.
+- The Go image that builds `smallwebwaf`: by digest.
@@ -1,79 +0,0 @@
-# GeoJS and the lookup database
-
-`smallwebwaf` looks up each client's AS number and country, through GeoJS by
-default or in a database file on your own host. The settings are under "Looking
-up the AS number and country" in [`settings.md`](settings.md); the reasons for
-the defaults are under "Lookup of AS number and country" in
-[`SPEC.md`](../SPEC.md).
-
-## GeoJS
-
-By default `smallwebwaf` asks GeoJS, a free web service that needs no account,
-about every new visitor's address. It asks whether or not a setting uses the
-answer, since the log line, the history, the ban notes and the metrics carry the
-AS number and country. These addresses are never sent:
-
- one in `SWWAF_ALLOW_NETS` or `SWWAF_DENY_NETS`;
- one under a ban;
- a private, loopback or link-local address, which no source can place.
-
-For an IPv6 visitor, GeoJS is asked about the first address of its group.
-Addresses are asked about together, up to 200 in one request
-(`https://get.geojs.io/v1/ip/geo.json?ip=a,b,c`), one request at a time. Each
-answer's `country_code`, `asn` and `organization_name` are read. An answer
-without a `country_code`, or with the `asn` `64512`, counts as unknown. Each
-answer is kept for seven days, in memory and in `lookups.json`, separately from
-the table of clients. Up to 100,000 answers are kept; past that, the answer used
-longest ago goes first.
-
-A request waits for its client's first answer only when a setting needs the
-answer before the request goes on. It waits up to `SWWAF_LOOKUP_TIMEOUT`. The
-settings that make it wait:
-
- a country list;
- `SWWAF_ADD_LOOKUP_HEADERS`;
- any setting under "Lower limits by AS number and country" in
-  [`settings.md`](settings.md).
-
-Otherwise the request goes on at once, logged without the answer. The answer
-reaches the client's history and ban notes when it comes. A client whose answer
-has not come in time counts as from an unknown country until it comes, and its
-later requests do not wait. While GeoJS fails, new visitors count as from an
-unknown country, which `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` refuses. GeoJS is
-then left alone for a second, and twice as long after each further failure, up
-to five minutes, and one `source_failure` alert is sent per cooldown.
-
-## The database file
-
-To keep your visitors' addresses on your own host, set
-`SWWAF_LOOKUP_SOURCE=off`, or set it to `file`. `file` looks every client up in
-the free IPinfo Lite database (`ipinfo_lite.mmdb`) at `SWWAF_LOOKUP_DB_PATH`,
-reading its `asn`, `as_name` and `country_code` fields. You download the
-database with an IPinfo account and mount it into the container; `smallwebwaf`
-never fetches it and holds no account or token for it. It answers at once, with
-nothing sent off the host. A client whose address it does not hold counts as
-from an unknown country.
-
-`smallwebwaf` reads the whole file at start. It reads the file again once it has
-gone 2 seconds without a change after you replace it. A replacement it cannot
-read is logged and alerted, and the file read before stays in use. Mount the
-directory that holds the file, not the file itself. Many editors and download
-tools save a file by replacing it, and a container keeps seeing the old file
-when only the file is mounted.
-
-IPinfo updates the database daily, and releases it under the Creative Commons
-Attribution-ShareAlike 4.0 licence. It asks for a link to IPinfo on the site
-that uses it, such as "IP address data is powered by IPinfo".
-
-## A client without a country
-
-A client the lookup cannot place has an unknown country and AS number. That is
-one of:
-
- a client on a private address;
- one GeoJS or the database does not know;
- one whose GeoJS answer has not come in time.
-
-`SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` refuses such a client, and the lower
-limits give it `SWWAF_UNKNOWN_LIMIT_PERCENT`. Nothing else treats it
-differently.
@@ -1,10 +1,8 @@
 # The metrics

-`GET /_smallwebwaf/metrics` answers in the Prometheus text format. The
-requirements are under "Metrics endpoint" in [`SPEC.md`](../SPEC.md); this file
-lists the metrics. Every metric carries the label `instance`, set to
-`SWWAF_INSTANCE_NAME`; Prometheus keeps it as `exported_instance` unless the
-scrape sets `honor_labels: true`. No metric carries a client's address.
+What `GET /_smallwebwaf/metrics` answers with. "Metrics endpoint" in
+[`SPEC.md`](../SPEC.md) describes the endpoint. Prometheus keeps the `instance`
+label as `exported_instance` unless the scrape sets `honor_labels: true`.

 ## Traffic

@@ -1,113 +0,0 @@
-# Reputation sources
-
-A reputation source judges a client by what others saw it do. None is on by
-default. The settings are under "Reputation sources" in
-[`settings.md`](settings.md); the reasons for the defaults are under
-"Reputation" in [`SPEC.md`](../SPEC.md). The sources are checked in this order,
-and a source the client is on refuses it, lowers its limits, or only notes it,
-as `SWWAF_BLOCKLIST_ACTION` and `SWWAF_REPUTATION_ACTION` say.
-
-## Blocklists
-
-`SWWAF_BLOCKLIST_URLS` lists text files of addresses and netblocks, one to a
-line, as the Spamhaus DROP list is written. Anything after a `;` or `#` is left
-out. An IPv4-mapped address such as `::ffff:192.0.2.0/120` is read as the IPv4
-netblock it stands for.
-
-Each list is fetched again `SWWAF_BLOCKLIST_REFRESH` after its last try, one
-list at a time. The file of `SWWAF_ASN_LIMIT_PERCENT_URL` is too.
-`reputation.json` keeps when each was last tried, so a restart does not fetch a
-list again before its time. A fetch fails when:
-
- the server answers other than `200`;
- the fetch does not finish within a minute;
- the list is longer than 16 MiB;
- a line is not an address or netblock, or, for the AS number file, not
-  `AS<number>:<percent>`.
-
-The copy fetched before stays in use, comment lines included. The failure is
-logged and raised as a `source_failure` alert. The log, the alerts, the ban
-notes and the metrics name each list by its URL, so keep a secret out of it.
-
-The Spamhaus DROP list is The Spamhaus Project's. Its terms, and what they mean
-for `SWWAF_BLOCKLIST_REFRESH` and for several instances on one host, are under
-"Reputation" in [`SPEC.md`](../SPEC.md). The copy in `reputation.json` keeps the
-list's date and copyright lines.
-
-## CrowdSec
-
-While `SWWAF_CROWDSEC_LAPI_URL` is set to the local API of a CrowdSec engine you
-run, `smallwebwaf` fetches its decision list every minute. It sends
-`SWWAF_CROWDSEC_LAPI_KEY` in the `X-Api-Key` header. The list is kept as a
-blocklist is kept. The decisions of the type `ban` on an address or a netblock
-are used. Any other, such as a captcha or a country, is left out. A decision
-lasts for the `duration` it had left when the engine answered.
-
-A request is refused when a decision still in force names its client. The
-client's netblock is banned until the decision ends, with the cause `crowdsec`.
-Only a client that sends a request is banned, so a long list does not fill
-`bans.json`. Such a ban is never made permanent, and does not lengthen the
-netblock's next ban for a broken limit. If you lift a ban while the decision is
-in force, the client's next request makes another. Delete the decision in
-CrowdSec first, such as with `cscli decisions delete --ip 203.0.113.9`, and lift
-the ban once the list has been fetched again. A fetch fails when:
-
- the engine answers other than `200`, a redirect included;
- the fetch does not finish within a minute;
- the answer is longer than 16 MiB;
- the answer is not a list of decisions.
-
-## DNS blocklists
-
-Each zone in `SWWAF_DNSBL_ZONES` is asked about a client's own address in the
-background, the first time the client is seen. The request goes on at once, and
-so does every request from the client until the zone has answered. The name
-asked about is the one RFC 5782 gives: the numbers of an IPv4 address reversed,
-or the 32 hex digits of an IPv6 address reversed. `192.0.2.99` is asked about as
-`99.2.0.192.dnsbl.dronebl.org`. An answer in `127.0.0.0/8` lists the client, but
-one in `127.255.255.0/24` is Spamhaus refusing the query. A name that does not
-exist does not list the client. These are failures:
-
- an answer in `127.255.255.0/24`;
- an answer outside `127.0.0.0/8`;
- a resolver error;
- no answer within `SWWAF_REPUTATION_TIMEOUT`.
-
-A failure is logged and alerted, and the zone is not asked again for a minute.
-Each verdict is kept for `SWWAF_REPUTATION_CACHE_TTL`, in memory and in
-`reputation.json`. Up to 100,000 verdicts are kept; past that, the one fetched
-longest ago goes first. At most 1,000 queries are under way at once.
-
-The key of a Spamhaus zone under `dq.spamhaus.net` is its first label.
-`smallwebwaf` shows `********` in its place wherever it names the zone. Only
-`reputation.json` keeps the zone with its key.
-
-## AbuseIPDB
-
-While `SWWAF_ABUSEIPDB_KEY` is set, `smallwebwaf` asks AbuseIPDB's check
-endpoint for the abuse confidence score of a client, from 0 to 100. Only a
-client that has committed an offence is checked. An offence is one of:
-
- a broken limit;
- a `ban` rule match or a trap path;
- a refusal by a `block` rule, the Core Rule Set or a token check.
-
-The check runs in the background, at the client's first request after the
-offence that no ban refuses, so no request waits. The score applies to the
-client's later requests. For an IPv6 client, AbuseIPDB is asked about the
-address of the request that set off the check, and the score is used for the
-whole group. A score at or over `SWWAF_ABUSEIPDB_MIN_SCORE` is a hit, and
-`SWWAF_REPUTATION_ACTION` says what is done. Each score is kept for
-`SWWAF_REPUTATION_CACHE_TTL`, up to 100,000 scores.
-
-At most `SWWAF_ABUSEIPDB_DAILY_BUDGET` checks are made in a day, counted in UTC
-and kept in `reputation.json`. A restart does not make the budget whole again.
-The check that spends the last of the budget is logged and alerted. No client is
-checked until the day ends. A check fails when:
-
- AbuseIPDB answers other than `200`;
- the answer gives no score;
- no answer comes within `SWWAF_REPUTATION_TIMEOUT`.
-
-A failure is logged and alerted, and no client is checked for a minute. The key
-is sent in the `Key` header and nowhere else, and is never logged.
@@ -1,8 +1,8 @@
 # The request log's fields

-`smallwebwaf` writes one JSON object per line on stdout for every request. The
-requirements are under "Request log" in [`SPEC.md`](../SPEC.md); this file lists
-the fields. A field that does not apply to a request is left out.
+The fields of the JSON object `smallwebwaf` writes for each request. "Request
+log" in [`SPEC.md`](../SPEC.md) says when a line is written and how the log is
+sent to a syslog server. A field that does not apply to a request is left out.

 ## Example

@@ -10,6 +10,16 @@ the fields. A field that does not apply to a request is left out.
 {"type":"request","time":"2026-10-03T12:00:00.123Z","instance":"fsn1app1/gitea","client_ip":"203.0.113.9","method":"GET","scheme":"https","host":"app.example","path":"/","query":"","protocol":"HTTP/1.1","status":200,"request_bytes":0,"response_bytes":5120,"referer":"","user_agent":"curl/8.9.1","request_id":"7Q2NHZ4KJ3VXW5YB6R3MEFTD2A","peer_ip":"172.18.0.2","forwarded_for":"203.0.113.9","client_group":"203.0.113.9/32","asn":"AS64496","as_name":"Example Net","country":"DE","request_headers":{"accept":"*/*"},"response_content_type":"text/html; charset=utf-8","upstream_status":200,"action":"forward","counts":{"minute":1,"hour":12,"day":40,"minute_bytes":5120,"hour_bytes":61440,"day_bytes":204800},"duration_total":3.217,"duration_checks":0.041,"duration_upstream_connect":0.052,"duration_upstream_first_byte":2.874,"duration_upstream_total":3.104}
 ```

+## Every line
+
+Every line has:
+
+- `type`: `request` (the process's own messages have `process`);
+- the standard web log fields;
+- `request_id`, `peer_ip` and `client_group`;
+- `asn`, `as_name` and `country`;
+- `action` and `duration_total`.
+
 ## Standard web log fields

 - `time`: when the request arrived, RFC 3339 with milliseconds, in UTC;
@@ -22,7 +32,7 @@ the fields. A field that does not apply to a request is left out.
 ## Request detail

 - `request_id`: the `X-Request-ID` a trusted proxy sent, or a new random one of
-  26 letters and digits. It goes to the app in `X-Request-ID`.
+  26 letters and digits.
 - `peer_ip`: the TCP peer, normally traefik.
 - `forwarded_for`: the `X-Forwarded-For` header as received.
 - `client_group`: the client as rate limiting counts it, an IPv4 address as a
@@ -66,15 +76,23 @@ the fields. A field that does not apply to a request is left out.
 - `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.
- `counts`: the client's requests in the minute, hour and day as rate limiting
-  counts them, this request included, as `minute`, `hour` and `day`; its bytes
-  as `minute_bytes`, `hour_bytes` and `day_bytes`. A count can have a fraction,
-  since each window is counted in two buckets with the earlier one weighted.
-  `counts` is left out when rate limiting did not count the request.
- `limit_hit`: the limit broken: `minute`, `hour` or `day` for a rate limit;
-  `minute_bytes`, `hour_bytes` or `day_bytes` for a byte limit; or
-  `error_burst`. A request whose bytes broke a limit was passed on whole, so its
-  `action` stays `forward`.
+- `counts`: the client's totals as rate limiting counts them, this request
+  included. It is left out when rate limiting did not count the request. It
+  holds:
+    - `minute`, `hour` and `day`: requests;
+    - `minute_bytes`, `hour_bytes` and `day_bytes`: bytes.
+
+    A count can have a fraction (see "Counting method" in
+    [`SPEC.md`](../SPEC.md)).
+
+- `limit_hit`: the limit broken:
+    - `minute`, `hour` or `day` for a rate limit;
+    - `minute_bytes`, `hour_bytes` or `day_bytes` for a byte limit;
+    - `error_burst`.
+
+    A request whose bytes broke a limit was passed on whole, so its `action`
+    stays `forward`.
+
 - `rule_ids`: the rule file rules that matched, in order, up to the one that
  refused.
 - `waf_score` and `waf_rule_ids`: the Core Rule Set's score and the rules that
@@ -84,7 +102,7 @@ the fields. A field that does not apply to a request is left out.
    - the CrowdSec decision list's URL;
    - DNS blocklist zones;
    - `abuseipdb`.
- `offence`: the kind of offence recorded, when one was.
+- `offence`: `limit`, for a request that broke a limit.
 - `ban_expires`: when the client's ban ends, for a request that made one or was
  refused under one: a time, or `permanent`.

@@ -99,30 +117,3 @@ All in milliseconds:
  connection;
 - `duration_upstream_first_byte`: until the first byte of the answer;
 - `duration_upstream_total`: until the end of the answer.
-
-## Every line
-
-Every line has `type`, the standard web log fields, `request_id`, `peer_ip`,
-`client_group`, `asn`, `as_name`, `country`, `action` and `duration_total`. The
-process's own messages share the stream with `"type":"process"`; request lines
-carry `"type":"request"`.
-
-## Sending the log to a syslog server
-
-While `SWWAF_LOG_REMOTE_URL` is set, every line on stdout is also sent to that
-server, as the message of an RFC 5424 syslog record. Over UDP each record is one
-datagram. Over TCP and TLS each record follows its length in bytes and a space.
-stdout is unchanged. The record carries:
-
- the facility from `SWWAF_LOG_REMOTE_FACILITY`;
- the severity informational;
- the time;
- the host's name;
- the app name from `SWWAF_LOG_REMOTE_APP_NAME`.
-
-Lines wait in a buffer of `SWWAF_LOG_REMOTE_BUFFER` lines, so a server that is
-slow or down never holds up a request. When the buffer is full, the oldest line
-is dropped. A failed connection is tried again a second later, and twice as long
-after each further failure, up to a minute. A line too long for one UDP datagram
-is dropped alone. As `smallwebwaf` stops, it spends at most two seconds sending
-the lines still waiting, and drops the rest. stdout has carried them.
@@ -1,10 +1,8 @@
 # Rule files

-`smallwebwaf` reads every `*.rules` file in `SWWAF_RULES_DIR`, in the order of
-their names, and checks each request against their rules in that order, unless
-the client is in `SWWAF_ALLOW_NETS`. The requirements the files meet are under
-"Rule files" in [`SPEC.md`](../SPEC.md). A file whose name starts with `.`, such
-as an editor's lock file, is not a rule file.
+The format of a rule file, and the default file the image ships. "Rule files" in
+[`SPEC.md`](../SPEC.md) says how the files are read, watched and mounted, and
+what each action leads to.

 ## The format

@@ -18,7 +16,7 @@ env-file       path        ban     (?i)^/\.env(\.[a-z]+)?$
 scanner-agent  user_agent  ban     (?i)\b(sqlmap|nikto|nuclei|wpscan)\b
 ```

- The id is letters, digits, `-` and `_`. No two rules share one. The log line,
+- The id is letters, digits, `-` and `_`, unique across all files. The log line,
  the metrics, the alerts and a ban's notes name the rule by it.
 - The target is what the regex is matched against:
    - `path`: the path without the query;
@@ -26,42 +24,10 @@ scanner-agent  user_agent  ban     (?i)\b(sqlmap|nikto|nuclei|wpscan)\b
    - `query`: the query as sent;
    - `method`, `host`, `user_agent` and `referer`;
    - `header:<Name>`: any one request header but `Host` and
-      `Transfer-Encoding`, which Go's HTTP server takes out of every request.
-
-    `path` and `uri` are matched both as sent and once percent-decoded, so that
-    an encoded probe does not slip past. A header sent more than once is matched
-    with its values joined by `, `. A header not sent is empty text. No body is
-    read; reading bodies is the Core Rule Set's job, once `SWWAF_WAF_BODY_LIMIT`
-    switches it on.
-
- The action is `log`, `block` or `ban`. `log` only notes the match in the log
-  line. `block` refuses the request with `403` and bans no one; the refusal
-  counts toward the error burst. `ban` refuses it and bans the client, as a
-  clear sign of attack. Matching stops at the first rule that refuses. Keep
-  `ban` for requests no real visitor sends. Anchor a path at the site root with
-  `^/`: a file of the same name deeper in a site can be ordinary content.
- The regex is in Go's syntax, RE2. It has no backreferences or lookaround, and
-  takes time linear in the text it reads, so no rule can be made to stall the
-  proxy. It matches anywhere in the target unless anchored with `^` and `$`.
-  `(?i)` at its front makes it ignore case.
-
-## Errors
-
-These stop the start, with a message naming the file and line:
-
- a line that is not a rule;
- a bad `header:` name, or a rule for `Host` or `Transfer-Encoding`;
- a regex that does not compile;
- an id used twice.
-
-So does a `SWWAF_RULES_DIR` that does not exist. An empty directory is not an
-error: the log says that no rules were loaded.
-
-While it runs, `smallwebwaf` watches the directory. It reads the files again
-once the directory has had no change for 2 seconds, so that a file still being
-written is read whole. If the files then hold such an error, the rules stay as
-they were. The log and a `file_error` alert name the file and line. Once the
-file is fixed, it is read again.
+      `Transfer-Encoding`.
+- The action is `log`, `block` or `ban`.
+- The regex is in Go's syntax, RE2. It matches anywhere in the target unless
+  anchored with `^` and `$`. `(?i)` at its front makes it ignore case.

 ## The default file

@@ -86,13 +52,10 @@ path-traversal   uri         block   (\.\./){2,}
 empty-agent      user_agent  log     ^$
 ```

-It is kept short and limited to patterns that are wrong for every app, with its
-path rules anchored at the site root. In front of gitea, `/.env` is a probe,
-while `/<owner>/<repo>/src/branch/main/.env.example` is a file in a repository
-that any visitor may open. Anything app-specific belongs in a file the app's
-`Dockerfile` adds or the deployer mounts. A request for `/wp-login.php`, for
-example, is a clear sign of attack in front of gitea and an ordinary login in
-front of WordPress. Such a rule goes in a file named to sort after the default:
+## A file of your own
+
+An app's `Dockerfile` adds rules of its own in a file named to sort after the
+default, such as `50-gitea.rules`:

 ```
 # 50-gitea.rules: WordPress probes, which gitea never serves
@@ -102,13 +65,3 @@ wp-probe         path        ban     (?i)^/(wp-login\.php|xmlrpc\.php|wp-admin/)
 ```dockerfile
 COPY 50-gitea.rules /etc/smallwebwaf/rules.d/50-gitea.rules
 ```
-
-## Mounting rule files
-
-A directory mounted over `/etc/smallwebwaf/rules.d` replaces the default file;
-single files mounted into it add to it. Many editors save a file by replacing
-it, and a container keeps seeing the old one when the file alone is mounted. So
-rules to be edited while `smallwebwaf` runs belong in a mounted directory, with
-a copy of the default file if the defaults are to stay. The lookup database is
-mounted the same way, for the same reason. To run without rules, mount an empty
-directory or set `SWWAF_RULES_ENABLED=false`.
@@ -1,27 +1,18 @@
 # Settings

-Every setting is an environment variable whose name starts with `SWWAF_`. Every
-setting has a default, so none has to be set. Settings are read once, at start.
-To change one, restart the container.
+Every setting, its default and the values it takes, in the groups of "Settings"
+in [`SPEC.md`](../SPEC.md). That section gives the conventions, the settings
+that take `off`, the `_FILE` form, and what each group does and why.

-A setting that is set to a value it cannot take stops the start. The process
-writes one line, `"type":"process"` with `"msg":"invalid setting"`, naming the
-variable and what is wrong with the value. It exits with status 1, and runit
-starts it again every second until the value is fixed. The entries below say
-which values each setting takes. Any other value stops the start. At start, the
-settings in effect are logged on one line. Tokens, keys and the paths of
-webhooks are shown as `********`.
-
-The forms of values:
+## Forms of values

 - A duration is Go's syntax, with `d` for days: `90s`, `15m`, `24h`, `7d`. Zero
  and negative durations are refused.
 - A size is a number of bytes with an optional `K`, `M` or `G`, which are powers
-  of 1024: `1K` is 1024 bytes, `512K`, `100M`, `5G`.
+  of 1024, so `1K` is 1024 bytes. Examples: `512K`, `100M`, `5G`.
 - A count is a whole number of requests, such as `1000`.
- `off` switches a setting off, where its entry below says it takes `off`.
 - A list is comma separated, with spaces around items ignored. An empty item is
-  refused. A list set but empty is an empty list, and replaces the default.
+  refused.
 - 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 of ISO 3166-1, in either case: `de` and `DE`
@@ -31,337 +22,59 @@ The forms of values:
 - A percentage is a whole number from 0 to 100.
 - A path prefix starts with `/`, such as `/assets/`.

-## Where it listens and what it protects
+## Core

- `SWWAF_LISTEN_ADDR` (default `:8080`): where `smallwebwaf` listens, an
-  optional host and a port. Keep the host empty: `:9000`, never
-  `127.0.0.1:9000`. The app must not listen on that port. The health check
-  follows the setting, and traefik's label must name the port.
 - `SWWAF_UPSTREAM_URL` (default `http://127.0.0.1:8081`): the app. An `http` or
-  `https` URL with a host and an optional port, and nothing more: no path, user
-  or query.
- `SWWAF_INSTANCE_NAME` (default: the container's host name, the first 12
-  characters of the container's id): the `instance` name in every log line,
-  alert and metric. Set it to a name that survives deploys and tells instances
-  apart, such as `fsn1app1/gitea`. It must be valid UTF-8. While
-  `SWWAF_ALERT_NTFY_URL` is set, it may hold no control character. While
-  `SWWAF_LOG_REMOTE_URL` is set and `SWWAF_LOG_REMOTE_APP_NAME` is not, it must
-  be 1 to 48 printable ASCII characters without a space.
- `SWWAF_MODE` (default `enforce`): `enforce`, or `observe` to ban no one and
-  log what `enforce` would have done. Observe mode still refuses a request over
-  a size or time limit, and one without the right token.
- `SWWAF_TRUSTED_PROXIES` (default `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16`,
-  the private address ranges): the netblocks whose `X-Forwarded-For` is
-  believed, normally where traefik comes from. Set but empty, it trusts nothing:
-  every TCP peer is then the client.
- `SWWAF_IPV6_GROUP_PREFIX` (default `64`): the length of the netblock that is
-  one IPv6 client, from 32 to 128. After a change, each IPv6 client starts
-  afresh. Existing bans keep refusing their netblocks until they end.
- `SWWAF_MAX_TRACKED_CLIENTS` (default `20000`): the most clients kept in memory
-  and in `clients.json`, a whole number above zero. Past it, the least recently
-  seen client is dropped first.
+  `https` URL with a host and an optional port, and nothing more.
+- `SWWAF_LISTEN_ADDR` (default `:8080`): where `smallwebwaf` listens: `:` and a
+  port, such as `:9000`. Leave the host out (see "Ports" in
+  [`SPEC.md`](../SPEC.md)).
+- `SWWAF_INSTANCE_NAME` (default: the container's host name): the `instance`
+  name in every log line, alert and metric, such as `fsn1app1/gitea`. Valid
+  UTF-8. No control character while `SWWAF_ALERT_NTFY_URL` is set. 1 to 48
+  printable ASCII characters without a space while `SWWAF_LOG_REMOTE_URL` is set
+  and `SWWAF_LOG_REMOTE_APP_NAME` is not.
+- `SWWAF_MODE` (default `enforce`): `enforce` or `observe`.
+- `SWWAF_TRUSTED_PROXIES` (default `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16`):
+  the netblocks whose `X-Forwarded-For` is believed. Set but empty, it trusts
+  nothing.
+- `SWWAF_IPV6_GROUP_PREFIX` (default `64`): the prefix length of an IPv6
+  client's group, from 32 to 128.
+- `SWWAF_MAX_TRACKED_CLIENTS` (default `20000`): the most clients kept, a whole
+  number above zero.
+- `SWWAF_MAX_BANS` (default `5000`): how many of its own bans `smallwebwaf`
+  keeps, a whole number above zero.

-## Time and size limits
+## Tokens

-Each request has limits on both sides: between the client and `smallwebwaf`, and
-between `smallwebwaf` and the app. Bodies stream through in both directions,
-except the part the Core Rule Set reads while `SWWAF_WAF_BODY_LIMIT` is set.
+- `SWWAF_ADMIN_TOKEN` (default unset): the token for the ban endpoints and
+  `/_smallwebwaf/clients/<ip>`. At least 32 characters.
+- `SWWAF_METRICS_TOKEN` (default unset): the token for `/_smallwebwaf/metrics`.
+  At least 32 characters.

- `SWWAF_CLIENT_REQUEST_TIMEOUT` (default `60s`): how long a client may take to
-  send its request line and headers, and then, from the end of the headers, its
-  body. A duration or `off`.
- `SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES` (default `32K`): the largest request
-  line and headers. A size over `4K`. It cannot be `off`: Go's HTTP server
-  always has such a limit.
- `SWWAF_CLIENT_IDLE_TIMEOUT` (default `120s`): how long a kept-open connection
-  may wait for its next request before it is closed. A duration or `off`. The
-  default is longer than the 90 seconds after which traefik closes an unused
-  connection, so traefik closes first.
- `SWWAF_CLIENT_RESPONSE_TIMEOUT` (default `30m`): how long the answer may take
-  to reach the client, from the end of the request to the last byte. A duration
-  or `off`.
- `SWWAF_UPSTREAM_REQUEST_TIMEOUT` (default `60s`): how long connecting to the
-  app and sending it the whole request may take. A duration or `off`.
- `SWWAF_UPSTREAM_RESPONSE_TIMEOUT` (default `30m`): how long the app may take
-  to send its whole answer. A duration or `off`.
- `SWWAF_REQUEST_MAX_BYTES` (default `100M`): the largest request body. A size
-  or `off`. A request that announces a larger body is refused before anything
-  reaches the app.
- `SWWAF_RESPONSE_MAX_BYTES` (default `5G`): the largest response body. A size
-  or `off`.
-
-In front of a code forge, a clone is a response and a push is a request. At the
-defaults, an upload over 100 MiB or slower than 60 seconds is cut off. A forge
-that takes large uploads needs `SWWAF_REQUEST_MAX_BYTES`,
-`SWWAF_CLIENT_REQUEST_TIMEOUT` and `SWWAF_UPSTREAM_REQUEST_TIMEOUT` raised to
-fit.
-
-What the client gets when a limit is passed is under "Size and time limits" in
-[`SPEC.md`](../SPEC.md).
-
-## Netblock lists
-
- `SWWAF_ALLOW_NETS` (default empty): netblocks whose clients skip every check,
-  such as your monitoring or your own network. The size and time limits still
-  apply to them. They are not looked up. They still need a token for the admin
-  endpoints.
- `SWWAF_RATE_LIMIT_EXEMPT_NETS` (default empty): netblocks whose clients are
-  exempt from rate limiting and the byte limits, such as a machine that talks to
-  the app all day. Everything else still applies to them.
- `SWWAF_DENY_NETS` (default empty): netblocks whose clients are always refused.
-  A client in both lists is let through.
-
-## Rate limiting and byte limits
-
- `SWWAF_RATE_LIMIT_PER_MINUTE` (default `1000`), `SWWAF_RATE_LIMIT_PER_HOUR`
-  (default `10000`) and `SWWAF_RATE_LIMIT_PER_DAY` (default `50000`): the most
-  requests a client may make in each window. A count or `off`. The defaults are
-  several times what one busy person produces. A browser loading a heavy page
-  makes a few hundred requests, and several people often share one address.
- `SWWAF_RATE_LIMIT_EXEMPT_PATHS` (default empty): path prefixes exempt from
-  rate limiting, such as `/assets/`. Their bytes are not counted either. The
-  path is matched exactly as sent, without the query, and is not
-  percent-decoded. `/assets/` matches `/assets/app.js`. It does not match
-  `/Assets/app.js`, `/%61ssets/app.js` or `/static/assets/app.js`. There are no
-  wildcards. A path holding `..`, a backslash or an encoded slash (`%2F`) is
-  never exempt, since the app may read it as a path outside the prefix.
- `SWWAF_BYTES_LIMIT_PER_MINUTE` (default `10G`), `SWWAF_BYTES_LIMIT_PER_HOUR`
-  (default `20G`) and `SWWAF_BYTES_LIMIT_PER_DAY` (default `50G`): the most
-  bytes a client may have counted in each window. A size or `off`. Bytes are
-  counted once the answer has ended, so a byte limit never cuts an answer short.
-  The client's next request is refused instead. Each default is above the
-  largest request and answer together, so at the defaults no single download
-  breaks a limit.
- `SWWAF_BYTES_COUNT` (default `both`): which body bytes the byte limits count:
-  `response`, `request` or `both`. For a WebSocket, what it carried each way
-  counts once it closes.
-
-## Looking up the AS number and country
-
- `SWWAF_LOOKUP_SOURCE` (default `geojs`): `geojs`, `file` or `off`. `geojs`
-  asks the GeoJS web service, which is then told the address of every new
-  visitor. `file` looks clients up in the IPinfo Lite database file at
-  `SWWAF_LOOKUP_DB_PATH`, and sends nothing off the host. `off` looks up no
-  client. With `off`, a setting that needs lookups stops the start:
-    - a country list;
-    - `SWWAF_ADD_LOOKUP_HEADERS`;
-    - an entry in `SWWAF_ASN_LIMIT_PERCENT`, `SWWAF_COUNTRY_LIMIT_PERCENT`,
-      `SWWAF_ASN_BYTES_PERCENT` or `SWWAF_COUNTRY_BYTES_PERCENT`;
-    - `SWWAF_UNKNOWN_LIMIT_PERCENT` below 100;
-    - `SWWAF_ASN_LIMIT_PERCENT_URL`;
-    - an anomaly threshold per AS number.
- `SWWAF_LOOKUP_DB_PATH` (default empty): the IPinfo Lite database file, in its
-  `.mmdb` form, for `SWWAF_LOOKUP_SOURCE=file`. `file` without it stops the
-  start, and so does setting it with any other source. A file that is missing or
-  cannot be read stops the start too.
- `SWWAF_LOOKUP_TIMEOUT` (default `1s`): how long a request waits for its
-  client's first answer from GeoJS when a setting needs it, and how long a
-  request to GeoJS may take. A duration; it cannot be `off`.
- `SWWAF_ADD_LOOKUP_HEADERS` (default `false`): `true` passes the app the
-  client's AS number in `X-Client-ASN` and its country in `X-Client-Country`. A
-  header whose value is unknown is left out. Whatever this setting says, any
-  such header the client sent is removed.
-
-See [`lookup.md`](lookup.md) for what each source sends where, and how long
-answers are kept.
-
-## Country lists
-
- `SWWAF_DENIED_COUNTRIES` (default empty): countries whose clients are refused,
-  such as `cn,ru,kp`.
- `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` (default empty): when set, the only
-  countries whose clients get through, such as `us,de`. A client whose country
-  cannot be found is refused too. Otherwise every new client would be let in
-  whenever GeoJS stops answering. A client on a private address has no country,
-  so it is refused unless it is in `SWWAF_ALLOW_NETS`.
-
-A country on both lists stops the start. What a refused request gets, and why
-the lists are empty by default, is under "Country lists" in
-[`SPEC.md`](../SPEC.md).
-
-## Lower limits by AS number and country
-
-Clients of the AS numbers and countries listed here get a percentage of every
-rate limit and byte limit. A lowered limit is rounded down. "Biased thresholds"
-in [`SPEC.md`](../SPEC.md) says why the lists are empty by default and why no
-budget is shared by a whole AS number or country.
-
- `SWWAF_ASN_LIMIT_PERCENT` (default empty): a list of AS numbers, each with `:`
-  and a percentage, such as `AS14061:50,AS16276:50,AS45102:25`. An AS number
-  listed twice is refused.
- `SWWAF_COUNTRY_LIMIT_PERCENT` (default empty): the same by country, such as
-  `cn:25,ru:50`.
- `SWWAF_ASN_BYTES_PERCENT` and `SWWAF_COUNTRY_BYTES_PERCENT` (default empty):
-  the same for the byte limits alone. For the AS numbers and countries they
-  list, they take the place of the two settings above.
- `SWWAF_UNKNOWN_LIMIT_PERCENT` (default `100`): the percentage of every limit
-  for a client without a country:
-    - one the lookup cannot place;
-    - one on a private address;
-    - one whose answer from GeoJS has not come in time.
- `SWWAF_ASN_LIMIT_PERCENT_URL` (default unset): the `http` or `https` URL of a
-  text file of such entries, one to a line, such as `AS14061:50`. One list can
-  then serve several instances. It is fetched and kept as a blocklist is. Where
-  it and `SWWAF_ASN_LIMIT_PERCENT` both give a percentage, the lower applies. A
-  URL that is also in `SWWAF_BLOCKLIST_URLS` stops the start.
-
-A client to which several percentages apply gets the lowest. The log line of
-each counted request, and the notes of each ban, say which setting lowered the
-limit.
-
-## Reputation sources
-
-None is on by default. A reputation source judges a client by what others saw it
-do. The defaults judge it by what it does to your service.
-
- `SWWAF_BLOCKLIST_URLS` (default empty): blocklists to fetch, such as
-  `https://www.spamhaus.org/drop/drop.txt`. Each is an `http` or `https` URL
-  without a user or a fragment. A URL listed twice is refused.
- `SWWAF_BLOCKLIST_REFRESH` (default `24h`): how long a list waits after its
-  last fetch, or failed try, before it is fetched again. A duration of `1h` or
-  more; it cannot be `off`. The Spamhaus lists may be fetched no more than once
-  an hour.
- `SWWAF_BLOCKLIST_ACTION` (default `deny`): what is done with a client on a
-  blocklist. `deny` refuses its requests. `limit:<percent>`, such as `limit:25`,
-  gives it that percentage of every limit. `log` only notes the list in the log
-  line and raises an alert.
- `SWWAF_DNSBL_ZONES` (default empty): the DNS blocklists to ask about each
-  client, such as `dnsbl.dronebl.org`. A DNS blocklist answers a DNS query for a
-  name made from an address, and so says whether the address is on it. A zone is
-  a DNS name of at most 189 characters. A Spamhaus zone carries its key, as in
-  `<key>.xbl.dq.spamhaus.net`, and is shown with the key masked. A zone listed
-  twice is refused, whatever its case or key. Do not name a zone meant for mail:
-  such a zone holds the residential addresses ordinary visitors come from.
- `SWWAF_DNSBL_RESOLVER` (default unset): the resolver to ask the zones through,
-  such as `192.0.2.53` or `[2001:db8::53]:5353`. An IP address with an optional
-  port, 53 when none is given. Unset, the host's resolver is used. Several zones
-  refuse queries that come through a public resolver.
- `SWWAF_ABUSEIPDB_KEY` (default unset): the key of your AbuseIPDB account.
-  While it is set, a client that has committed an offence is checked. A control
-  character in it is refused.
- `SWWAF_ABUSEIPDB_MIN_SCORE` (default `75`): the least abuse confidence score,
-  from 0 to 100, that is a hit.
- `SWWAF_ABUSEIPDB_DAILY_BUDGET` (default `900`): the most checks made in a day,
-  in UTC, a whole number above zero. AbuseIPDB's free accounts may make 1,000.
- `SWWAF_CROWDSEC_LAPI_URL` (default unset): the local API of a CrowdSec engine
-  you run, such as `http://172.17.0.1:8080`. An `http` or `https` URL without a
-  user or a fragment. Its decision list is at `v1/decisions` under that URL, and
-  is fetched every minute. Set without the key, it stops the start. So does a
-  decision list URL that is also in `SWWAF_BLOCKLIST_URLS`, or that is
-  `SWWAF_ASN_LIMIT_PERCENT_URL`.
- `SWWAF_CROWDSEC_LAPI_KEY` (default unset): the key the engine gave for
-  `smallwebwaf`, as `cscli bouncers add smallwebwaf` prints it. Set without the
-  URL, it stops the start.
- `SWWAF_REPUTATION_ACTION` (default `limit:25`): what is done with a client on
-  a DNS blocklist, or one whose AbuseIPDB score is a hit. `deny`,
-  `limit:<percent>` or `log`, as for `SWWAF_BLOCKLIST_ACTION`. Such a verdict is
-  less certain than the Spamhaus DROP list, so by default the client gets a
-  quarter of every limit.
- `SWWAF_REPUTATION_CACHE_TTL` (default `24h`): how long a zone's verdict or
-  AbuseIPDB's score is used. A duration; it cannot be `off`.
- `SWWAF_REPUTATION_TIMEOUT` (default `2s`): how long a query to a zone or a
-  check with AbuseIPDB may take. A duration; it cannot be `off`.
-
-See [`reputation.md`](reputation.md) for how each source is asked and what it
-does with the answer.
-
-## Attack detection
-
- `SWWAF_RULES_DIR` (default `/etc/smallwebwaf/rules.d`): the directory of the
-  rule files (see [`rules.md`](rules.md)). A directory that cannot be read stops
-  the start. An empty one is no error.
- `SWWAF_RULES_ENABLED` (default `true`): `false` reads no rule file.
- `SWWAF_TRAP_PATHS` (default empty): paths the app never serves and only
-  scanners ask for, such as `/wp-login.php,/xmlrpc.php` in front of a code
-  forge. A request for one bans the client, as a `ban` rule does. Each starts
-  with `/` and holds no `?`. A trap path is matched whole, without the query,
-  against the path as sent and once percent-decoded. `/wp-login.php` matches
-  `/wp-login.php?x=1` and `/%77p-login.php`. It does not match `/wp-login.php/`
-  or `/blog/wp-login.php`.
- `SWWAF_WAF_MODE` (default `block`): what the Core Rule Set does with a request
-  it takes for an attack. `block` refuses it with `403`. `detect` lets it
-  through, logged and alerted. `off` inspects no request.
- `SWWAF_WAF_PARANOIA_LEVEL` (default `1`): the Core Rule Set's paranoia level,
-  from 1 to 4. Each level up runs more rules. Those find more attacks, and take
-  more ordinary requests for attacks.
- `SWWAF_WAF_ANOMALY_THRESHOLD` (default `5`): the score at which a request is a
-  match. Each rule that matches adds to the request's score, and a rule rated
-  critical adds 5. So by default one such rule is enough. A whole number above
-  zero, or `off`. With `off` no request is a match, and scores are still logged.
- `SWWAF_WAF_DISABLED_RULES` (default
-  `920340,920420,920440,920640,930130,930140`): the ids of Core Rule Set rules
-  to switch off. The log line names the rules a request matched, so a rule that
-  refuses your app's ordinary requests can be found there. "Attack detection" in
-  [`SPEC.md`](../SPEC.md) says what the six default ids refuse and why they are
-  off. A list you give replaces the default, so name these six ids in it to keep
-  them off. An id must be a whole number above zero. An id from 900000 to 900999
-  is refused: those are the rules that set the Core Rule Set up, and
-  `smallwebwaf`'s own.
- `SWWAF_WAF_EXEMPT_PATHS` (default empty): path prefixes the Core Rule Set does
-  not inspect, matched as `SWWAF_RATE_LIMIT_EXEMPT_PATHS` is.
- `SWWAF_WAF_BODY_LIMIT` (default `off`): `off` reads no request body. A size,
-  at most `1G`, switches body inspection on. The Core Rule Set then reads a form
-  data or multipart body up to that size, and the rest streams on to the app. It
-  reads a JSON or XML body no larger than that size, since those cannot be read
-  in part. Any other body, such as a git push, reaches the app uninspected. See
-  [`core-rule-set.md`](core-rule-set.md).
- `SWWAF_ERROR_BURST_THRESHOLD` (default `30`): the most refusals of one client
-  in a minute for a rule match, a trap path, a Core Rule Set match or a failed
-  token check. One more bans the client, as a broken rate limit does. A count or
-  `off`. The app's own `401` and `404` answers are not counted.
-
-## How long bans last and what they cover
-
- `SWWAF_BAN_RESPONSE` (default `403`): how a refused client is answered: `403`,
-  `429`, or `close` to close the connection without an answer. A `block` rule
-  and the Core Rule Set always answer `403`.
- `SWWAF_LIMIT_BAN_DURATION` (default `1h`): the ban for a first broken rate
-  limit, byte limit or error burst. A duration; it cannot be `off`.
- `SWWAF_LIMIT_BAN_REPEAT_WINDOW` (default `24h`): a client that breaks a limit
-  again within this time after its ban ended is banned three times as long. A
-  duration; it cannot be `off`.
- `SWWAF_MAX_BAN_DURATION` (default `7d`): a ban for a broken limit that would
-  be longer is permanent instead. A duration; it cannot be `off`.
- `SWWAF_ATTACK_BAN_DURATION` (default `7d`): the ban for a first clear sign of
-  attack. A duration; it cannot be `off`.
- `SWWAF_MAX_BANS` (default `5000`): the most bans `smallwebwaf` made that are
-  kept, whether past, active or permanent. A whole number above zero. Bans whose
-  cause is `admin` are kept besides and never dropped (see
-  [`bans.md`](bans.md)).
- `SWWAF_BAN_SCOPE_V4_PREFIX` (default `32`): the length of the netblock around
-  an IPv4 client that a ban covers, from 0 to 32. `24` bans the surrounding /24.
-  An IPv6 ban covers the client's group.
-
-## Where and how often the state files are written
+## State files

 - `SWWAF_STATE_DIR` (default `/var/lib/smallwebwaf`): the directory of the state
-  files, an absolute path. A directory that does not exist or cannot be written
-  stops the start.
+  files, an absolute path that exists and can be written.
 - `SWWAF_STATE_WRITE_DELAY` (default `10s`): how long `bans.json` waits to be
-  written after a ban is made, lifted or made permanent. Every change in between
-  goes into the same write. A duration; it cannot be `off`.
+  written after a ban is made, lifted or made permanent. A duration.
 - `SWWAF_STATE_COUNTER_INTERVAL` (default `15m`): how often every state file is
-  written. A duration; it cannot be `off`.
+  written. A duration.

 ## Logging

+- `SWWAF_LOG_LEVEL` (default `info`): the least severe of `smallwebwaf`'s own
+  messages that are written: `debug`, `info`, `warn` or `error`.
 - `SWWAF_LOG_REQUEST_HEADERS` (default
  `accept,accept-language,accept-encoding,content-type,origin,range`): the
-  request headers to record in the log line, in either case. `Authorization`,
-  `Cookie` and `Set-Cookie` are never logged, even if listed. `Host` and
-  `Transfer-Encoding` are refused: Go's HTTP server takes them out of the
-  request. The host is the field `host`.
- `SWWAF_LOG_LEVEL` (default `info`): the least severe of `smallwebwaf`'s own
-  messages that are written: `debug`, `info`, `warn` or `error`. No message is
-  at `debug`. It holds back no request log line. `warn` and `error` hold back
-  the line of settings at start.
- `SWWAF_LOG_REMOTE_URL` (default unset): a syslog server every line on stdout
-  is also sent to, such as `syslog+tls://logs.example:6514`. The forms are
-  `syslog+udp://`, `syslog+tcp://` and `syslog+tls://`, each with a host and a
-  port and nothing more.
+  request headers recorded in the log line, in either case. `Host` and
+  `Transfer-Encoding` are refused; the host is the field `host`.
+- `SWWAF_LOG_REMOTE_URL` (default unset): a syslog server that also gets every
+  line written to stdout: `syslog+udp://`, `syslog+tcp://` or `syslog+tls://`,
+  each with a host and a port and nothing more.
 - `SWWAF_LOG_REMOTE_TLS_CA_FILE` (default unset): a file of PEM certificates
  that a `syslog+tls` server's certificate must chain to, instead of the host's
-  own. A file that cannot be read, or holds no certificate, stops the start.
+  own. A file that cannot be read, or holds no certificate, is refused.
 - `SWWAF_LOG_REMOTE_BUFFER` (default `10000`): the most lines held while they
  wait to be sent, a whole number above zero.
 - `SWWAF_LOG_REMOTE_FACILITY` (default `local0`): the syslog facility: `kern`,
@@ -370,53 +83,200 @@ does with the answer.
 - `SWWAF_LOG_REMOTE_APP_NAME` (default: `SWWAF_INSTANCE_NAME`): the app name in
  each syslog record, 1 to 48 printable ASCII characters without a space.

-## Tokens and metrics
+## Metrics

- `SWWAF_ADMIN_TOKEN` (default unset): the token for the ban endpoints and
-  `/_smallwebwaf/clients/<ip>`. A long random value of at least 32 characters.
-  Unset, those endpoints are off. Give it as a file to keep it from the app (see
-  "Settings given as files" below).
- `SWWAF_METRICS_TOKEN` (default unset): the token a scraper sends for
-  `/_smallwebwaf/metrics`, at least 32 characters. Unset, the metrics are off.
-  It is separate from the admin token, so a scraper cannot manage bans.
 - `SWWAF_METRICS_TOP_N` (default `50`): how many AS numbers and how many
-  countries get series of their own in the metrics. The rest count as `other`. A
-  whole number above zero.
+  countries get series of their own. A whole number above zero.

-## Alert destinations
+## Static lists
+
+- `SWWAF_ALLOW_NETS` (default empty): netblocks you trust, such as your
+  monitoring (see step 3 in [`SPEC.md`](../SPEC.md)).
+- `SWWAF_RATE_LIMIT_EXEMPT_NETS` (default empty): netblocks whose clients are
+  exempt from rate limiting and the byte limits.
+- `SWWAF_DENY_NETS` (default empty): netblocks whose clients are refused (see
+  step 3 in [`SPEC.md`](../SPEC.md)).
+
+## Request rate limits, per client
+
+- `SWWAF_RATE_LIMIT_PER_MINUTE` (default `1000`), `SWWAF_RATE_LIMIT_PER_HOUR`
+  (default `10000`) and `SWWAF_RATE_LIMIT_PER_DAY` (default `50000`): the most
+  requests a client may make in each window. A count or `off`.
+- `SWWAF_RATE_LIMIT_EXEMPT_PATHS` (default empty): path prefixes exempt from
+  rate limiting and the byte limits, such as `/assets/`.
+
+## Byte limits, per client
+
+- `SWWAF_BYTES_LIMIT_PER_MINUTE` (default `10G`), `SWWAF_BYTES_LIMIT_PER_HOUR`
+  (default `20G`) and `SWWAF_BYTES_LIMIT_PER_DAY` (default `50G`): 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`.
+
+## Size and time limits
+
+- `SWWAF_CLIENT_REQUEST_TIMEOUT` (default `60s`): how long a client may take to
+  send its request line and headers, and then, from the end of the headers, its
+  body. A duration or `off`.
+- `SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES` (default `32K`): the largest request
+  line and headers. A size over `4K`; never `off`.
+- `SWWAF_CLIENT_IDLE_TIMEOUT` (default `120s`): how long a kept-open connection
+  may wait for its next request before it is closed. A duration or `off`.
+- `SWWAF_CLIENT_RESPONSE_TIMEOUT` (default `30m`): how long the answer may take
+  to reach the client, from the end of the request to the last byte. A duration
+  or `off`.
+- `SWWAF_UPSTREAM_REQUEST_TIMEOUT` (default `60s`): how long connecting to the
+  app and sending it the whole request may take. A duration or `off`.
+- `SWWAF_UPSTREAM_RESPONSE_TIMEOUT` (default `30m`): how long the app may take
+  to send its whole answer. A duration or `off`.
+- `SWWAF_REQUEST_MAX_BYTES` (default `100M`): the largest request body. A size
+  or `off`.
+- `SWWAF_RESPONSE_MAX_BYTES` (default `5G`): the largest response body. A size
+  or `off`.
+
+## Lookup of AS number and country
+
+- `SWWAF_LOOKUP_SOURCE` (default `geojs`): `geojs`, `file` or `off`. `off` stops
+  the start while a setting that needs a lookup is set:
+    - the two country lists;
+    - `SWWAF_ADD_LOOKUP_HEADERS`;
+    - the four biased threshold lists and `SWWAF_ASN_LIMIT_PERCENT_URL`;
+    - `SWWAF_UNKNOWN_LIMIT_PERCENT` below `100`;
+    - an anomaly threshold per AS number.
+- `SWWAF_LOOKUP_DB_PATH` (default empty): the IPinfo Lite database file, in its
+  `.mmdb` form, for `SWWAF_LOOKUP_SOURCE=file`.
+- `SWWAF_LOOKUP_TIMEOUT` (default `1s`): how long a request waits for its
+  client's first answer from GeoJS, and how long a request to GeoJS may take. A
+  duration; never `off`.
+- `SWWAF_ADD_LOOKUP_HEADERS` (default `false`): `true` passes the app the
+  client's AS number in `X-Client-ASN` and its country in `X-Client-Country`.
+
+## Country lists
+
+- `SWWAF_DENIED_COUNTRIES` (default empty): countries whose clients are refused,
+  such as `cn,ru,kp`.
+- `SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES` (default empty): when set, the only
+  countries whose clients get through, such as `us,de`. A country on both lists
+  stops the start.
+
+## Biased thresholds
+
+- `SWWAF_ASN_LIMIT_PERCENT` (default empty): a list of AS numbers, each with `:`
+  and a percentage, such as `AS14061:50,AS16276:50,AS45102:25`. An AS number
+  listed twice is refused.
+- `SWWAF_COUNTRY_LIMIT_PERCENT` (default empty): the same by country, such as
+  `cn:25,ru:50`.
+- `SWWAF_ASN_BYTES_PERCENT` and `SWWAF_COUNTRY_BYTES_PERCENT` (default empty):
+  the same, for the byte limits alone.
+- `SWWAF_UNKNOWN_LIMIT_PERCENT` (default `100`): the percentage for a client the
+  lookup cannot place.
+- `SWWAF_ASN_LIMIT_PERCENT_URL` (default unset): the `http` or `https` URL of a
+  text file with one AS number and percentage on each line, such as
+  `AS64496:50`. A URL that is also in `SWWAF_BLOCKLIST_URLS` is refused.
+
+## Attack detection
+
+- `SWWAF_RULES_DIR` (default `/etc/smallwebwaf/rules.d`): the directory of the
+  rule files.
+- `SWWAF_RULES_ENABLED` (default `true`): `false` reads no rule file.
+- `SWWAF_TRAP_PATHS` (default empty): paths only scanners ask for, such as
+  `/wp-login.php,/xmlrpc.php`. Each starts with `/` and holds no `?`.
+- `SWWAF_WAF_MODE` (default `block`): `off`, `detect` or `block`.
+- `SWWAF_WAF_PARANOIA_LEVEL` (default `1`): the Core Rule Set's paranoia level,
+  from 1 to 4.
+- `SWWAF_WAF_ANOMALY_THRESHOLD` (default `5`): the score at which a request is a
+  match. A whole number above zero, or `off`.
+- `SWWAF_WAF_DISABLED_RULES` (default
+  `920340,920420,920440,920640,930130,930140`): the ids of Core Rule Set rules
+  to switch off. Each a whole number above zero. An id from 900000 to 900999 is
+  refused: those are the rules that set the Core Rule Set up, and
+  `smallwebwaf`'s own.
+- `SWWAF_WAF_EXEMPT_PATHS` (default empty): path prefixes the Core Rule Set does
+  not inspect.
+- `SWWAF_WAF_BODY_LIMIT` (default `off`): `off`, or how much of a request body
+  the Core Rule Set reads, a size of at most `1G`.
+- `SWWAF_ERROR_BURST_THRESHOLD` (default `30`): the most refusals of one client
+  in a minute for a rule match, a trap path, a Core Rule Set match or a failed
+  token check. A count or `off`.
+
+## Ban lengths, response and scope
+
+- `SWWAF_BAN_RESPONSE` (default `403`): `403`, `429` or `close`.
+- `SWWAF_LIMIT_BAN_DURATION` (default `1h`): the ban for a first broken limit. A
+  duration.
+- `SWWAF_LIMIT_BAN_REPEAT_WINDOW` (default `24h`): the time after a ban ends
+  within which breaking a limit again lengthens the next ban. A duration.
+- `SWWAF_MAX_BAN_DURATION` (default `7d`): the longest ban for a broken limit;
+  one that would be longer is permanent. A duration.
+- `SWWAF_ATTACK_BAN_DURATION` (default `7d`): the ban for a first clear sign of
+  attack. A duration.
+- `SWWAF_BAN_SCOPE_V4_PREFIX` (default `32`): how much a ban on an IPv4 client
+  covers: the prefix length of its netblock, from 0 to 32.
+
+## Reputation
+
+- `SWWAF_BLOCKLIST_URLS` (default empty): blocklists to fetch, such as
+  `https://www.spamhaus.org/drop/drop.txt`. Each an `http` or `https` URL
+  without a user or a fragment. A URL listed twice is refused.
+- `SWWAF_BLOCKLIST_REFRESH` (default `24h`): how long a list waits after its
+  last try before it is fetched again. A duration of `1h` or more.
+- `SWWAF_BLOCKLIST_ACTION` (default `deny`): `deny`, `limit:<percent>` or `log`.
+- `SWWAF_DNSBL_ZONES` (default empty): the DNS blocklists to ask, such as
+  `dnsbl.dronebl.org`. Each a DNS name of at most 189 characters. A Spamhaus
+  zone carries its key, as in `<key>.xbl.dq.spamhaus.net`. A zone listed twice
+  is refused, whatever its case or key.
+- `SWWAF_DNSBL_RESOLVER` (default unset): the resolver to ask the zones through,
+  such as `192.0.2.53` or `[2001:db8::53]:5353`. An IP address with an optional
+  port, 53 when none is given. Unset, the host's resolver is used.
+- `SWWAF_ABUSEIPDB_KEY` (default unset): the key of your AbuseIPDB account. A
+  control character in it is refused.
+- `SWWAF_ABUSEIPDB_MIN_SCORE` (default `75`): the least abuse confidence score,
+  from 0 to 100, that is a hit.
+- `SWWAF_ABUSEIPDB_DAILY_BUDGET` (default `900`): the most checks made in a day,
+  a whole number above zero. AbuseIPDB's free accounts may make 1,000.
+- `SWWAF_CROWDSEC_LAPI_URL` (default unset): the local API of a CrowdSec engine
+  you run, such as `http://172.17.0.1:8080`. An `http` or `https` URL without a
+  user or a fragment; its decision list is at `v1/decisions` under it. Set
+  without the key, it is refused. So is a decision list URL that is also in
+  `SWWAF_BLOCKLIST_URLS`, or that is `SWWAF_ASN_LIMIT_PERCENT_URL`.
+- `SWWAF_CROWDSEC_LAPI_KEY` (default unset): the key the engine gave for
+  `smallwebwaf`, as `cscli bouncers add smallwebwaf` prints it. Set without the
+  URL, it is refused.
+- `SWWAF_REPUTATION_ACTION` (default `limit:25`): `deny`, `limit:<percent>` or
+  `log`, for DNS blocklist and AbuseIPDB hits.
+- `SWWAF_REPUTATION_CACHE_TTL` (default `24h`): how long a zone's verdict or
+  AbuseIPDB's score is used. A duration.
+- `SWWAF_REPUTATION_TIMEOUT` (default `2s`): how long a query to a zone or a
+  check with AbuseIPDB may take. A duration.
+
+## Alerting

 - `SWWAF_ALERT_WEBHOOK_URL` (default unset): the webhook that receives each
  alert as a JSON object. An `http` or `https` URL without a user or a fragment.
-  The settings logged at start show its path and query as `********`, since many
-  webhooks carry their secret there.
 - `SWWAF_ALERT_WEBHOOK_HEADERS` (default empty): headers sent with each post,
  such as `Authorization:Bearer 0123456789abcdef`. A list of name, `:` and
  value. A value cannot hold a comma.
 - `SWWAF_ALERT_SLACK_WEBHOOK_URL` (default unset): the Slack incoming webhook
-  that receives each alert as a message. It is checked and masked as the webhook
-  URL is.
+  that receives each alert as a message, checked as the webhook URL is.
 - `SWWAF_ALERT_NTFY_URL` (default unset): the ntfy topic that receives each
-  alert, as the topic's full URL, such as `https://ntfy.sh/my-alerts`. It is
-  checked and masked as the webhook URL is.
- `SWWAF_ALERT_NTFY_TOKEN` (default unset): an ntfy access token, sent as
-  `Authorization: Bearer <token>`. A control character in it is refused.
+  alert, as the topic's full URL, such as `https://ntfy.sh/my-alerts`, checked
+  as the webhook URL is.
+- `SWWAF_ALERT_NTFY_TOKEN` (default unset): an ntfy access token. A control
+  character in it is refused.
 - `SWWAF_ALERT_EVENTS` (default
  `ban,permanent_ban,waf_block,anomaly,reputation_hit,source_failure,file_error`):
-  the events alerts are sent for. Any other name is refused.
- `SWWAF_ALERT_COOLDOWN` (default `15m`): how long a repeat of an alert is held
-  back. A duration or `off`.
- `SWWAF_ALERT_MAX_PER_HOUR` (default `60`): the most alerts sent in an hour.
-  The rest are rolled into one summary. A whole number above zero, or `off`.
-
-See [`alerts.md`](alerts.md) for the events and what each destination gets.
+  the event types alerts are sent for, from those in [`alerts.md`](alerts.md)
+  but `summary`. Any other name is refused.
+- `SWWAF_ALERT_COOLDOWN` (default `15m`): how long after an alert is sent its
+  repeats are held back. A duration or `off`.
+- `SWWAF_ALERT_MAX_PER_HOUR` (default `60`): the most alerts sent in an hour. A
+  whole number above zero, or `off`.

 ## Anomaly thresholds

-These only alert. They refuse and ban nothing. Each scope has four thresholds:
-the most requests and the most bytes counted in a minute and in an hour.
-Requests are counts, bytes are sizes. Each is `off` by default. What is unusual
-depends on each service's normal traffic, which the metrics show. The four
-thresholds per client are:
+Each scope has four thresholds: the most requests and the most bytes counted in
+a minute and in an hour. Requests are counts, bytes are sizes. Each is `off` by
+default. The four thresholds per client are:

 - `SWWAF_ANOMALY_CLIENT_REQUESTS_PER_MINUTE`;
 - `SWWAF_ANOMALY_CLIENT_REQUESTS_PER_HOUR`;
@@ -432,30 +292,17 @@ as `REQUESTS_PER_MINUTE`:
      client;
    - `SWWAF_ANOMALY_NET_V6_PREFIX` (default `48`, from 0 to 128) for an IPv6
      client.
- `SWWAF_ANOMALY_ASN_...`: per AS number. Needs lookups on.
+- `SWWAF_ANOMALY_ASN_...`: per AS number.
 - `SWWAF_ANOMALY_TOTAL_...`: the whole service.
 - `SWWAF_WATCH_...`: each netblock in `SWWAF_WATCH_NETS`, as a whole.
  `SWWAF_WATCH_NETS` (default empty) is a list of name, `=` and netblock, such
  as `office=203.0.113.0/24,scraper-x=198.51.100.0/22`. An item without `=` or a
  name, or with a bad netblock, is refused. So is a name used twice.

-Every request but the health check is counted, whatever was done with it,
-clients in `SWWAF_ALLOW_NETS` included. At most 20,000 counters are kept.
-`alerts.json` keeps them across a restart.
-
 ## Settings given as files

-Any setting may be given as a file holding its value. Add `_FILE` to the
-setting's name: `SWWAF_METRICS_TOKEN_FILE` names the file that holds
-`SWWAF_METRICS_TOKEN`. The file's contents are the value, less one newline at
-the end. They are checked as the value itself would be. Setting both forms stops
-the start, and so does naming a file that cannot be read.
-`SWWAF_LOG_REMOTE_TLS_CA_FILE` already holds a file name, so it has no `_FILE`
-form.
-
-A token given as a file is out of the app's reach only while the `smallwebwaf`
-user alone can read the file. Make it on the host, owned by uid 65532 with mode
-`0400`:
+To give a token as a file, as "Tokens" under "Deployment" in
+[`SPEC.md`](../SPEC.md) describes, make the file on the host:

 ```sh
 mkdir -p /srv/app/tokens
@@ -464,7 +311,7 @@ chown 65532:65532 /srv/app/tokens/metrics
 chmod 0400 /srv/app/tokens/metrics
 ```

-Mount its directory into the container read-only, and name the file:
+Then mount its directory into the container read-only, and name the file:

 ```sh
 docker run \
@@ -477,7 +324,8 @@ docker run \

 A few limits are fixed rather than settings:

- at most 100,000 GeoJS answers are kept, for 7 days each;
+- at most 100,000 GeoJS answers are kept;
 - at most 100,000 DNS blocklist verdicts and 100,000 AbuseIPDB scores are kept;
 - at most 1,000 DNS blocklist queries are under way at once;
- the CrowdSec decision list is fetched again a minute after the last fetch.
+- at most 20,000 anomaly counters are kept;
+- each alert destination's queue holds at most 1,000 alerts.
@@ -1,102 +1,104 @@
 # State files

-`smallwebwaf` keeps its state in memory, and a copy of it in five JSON files in
-`SWWAF_STATE_DIR`. The files are meant for people as well: you can read or edit
-them at any time, and the running `smallwebwaf` takes the edit in. The
-requirements they meet are under "Persistent state" in [`SPEC.md`](../SPEC.md).
-
-## The files
-
+The five JSON files in `SWWAF_STATE_DIR`, and what each holds. "Persistent
+state" in [`SPEC.md`](../SPEC.md) says how they are written, read and edited.
 Each has a top-level `version` of 1.

- `bans.json`: active and past bans, up to `SWWAF_MAX_BANS` that `smallwebwaf`
-  made and every ban you made, indented to be read. Per entry:
-    - the netblock, start and expiry (`null` for permanent);
-    - the cause: `attack`, `limit`, `admin` or `crowdsec`;
-    - a short reason;
-    - when it was lifted, if you lifted it;
-    - the notes (see [`bans.md`](bans.md)).
- `clients.json`: per client, its minute, hour and day counters and its history
-  since it was first seen, one client per line, so `grep` shows everything about
-  one. The history holds:
-    - the first and last time seen;
-    - the AS number, AS name and country last looked up, and when;
-    - total requests, and how many were forwarded and how many refused;
-    - bytes in each direction;
-    - responses by status class;
-    - offences by kind: `limit`, `attack`, `rule_blocked`, `waf_blocked` and
-      `token_refused`.
+## `bans.json`

-    Clients that were never banned are kept too, so every client's history
-    survives a restart.
+Active and past bans: every ban an admin made, and up to `SWWAF_MAX_BANS` of
+those `smallwebwaf` made. Per entry:

- `lookups.json`: GeoJS answers, one per line: the AS number, AS name and
-  country, when GeoJS was asked and when the answer was last used.
- `reputation.json`:
-    - the last good copy of each list fetched from a URL, with when it was last
-      tried;
-    - each DNS blocklist verdict still in use;
-    - AbuseIPDB's scores, and the checks spent today.
- `alerts.json`:
-    - the anomaly counters;
-    - the alert cooldowns: for each event and netblock, source, file or thing
-      counted, when it was last sent and the count of repeats held back since;
-    - the alerts sent and held back in the current hour;
-    - the alerts waiting for each destination.
+- `netblock`, `start` and `expires` (`null` for a permanent ban);
+- `cause`: `attack`, `limit`, `admin` or `crowdsec`;
+- `reason`: a short reason;
+- `lifted`: when an admin lifted it, if one did;
+- `notes`: the notes below.

-Times are RFC 3339 UTC. Durations and sizes are plain numbers, with the unit in
-the field name. `bans.json`, `reputation.json` and `alerts.json` are indented;
-`clients.json` and `lookups.json` put each entry on one line.
+An entry an admin adds needs `netblock`, `start` and `expires`; `reason`,
+`notes` and `cause` may be left out, and the cause is then `admin`:
+
+```json
+{
+    "version": 1,
+    "bans": [
+        {
+            "netblock": "203.0.113.0/24",
+            "start": "2026-10-06T12:00:00Z",
+            "expires": null,
+            "reason": "probes for logins"
+        }
+    ]
+}
+```
+
+"Bans" in [`SPEC.md`](../SPEC.md) says how an edit lifts, keeps or forgets a
+ban. The notes:
+
+- `asn`, `as_name` and `country`: the client's, added when the lookup answers
+  (empty when lookups are off);
+- for a broken limit, `kind` (`requests`, `bytes` or `refusals`), `limit`,
+  `window` and `count`: what the limit was on, the limit, its window and the
+  count reached;
+- `limit_percent` and `limit_percent_setting`: the client's percentage of that
+  limit and the setting that gave it, when a setting lowered it;
+- for a clear sign of attack, `rule_id` and `target`, or `trap_path`;
+- `reputation`: the sources the client was on, each with its `source` and, for
+  AbuseIPDB, its `score`;
+- `request`: the request that caused the ban, each text cut to 256 bytes:
+    - `time`, `method` and `host`;
+    - `path`, with its query string;
+    - `status` and `user_agent`;
+- `requests` and `refused`: the netblock's requests since it was first seen, and
+  how many this ban has refused so far, kept up to date while the ban lasts;
+- `earlier_bans`: how many earlier bans the netblock had, by cause.
+
+## `clients.json`
+
+Per client, one per line: its minute, hour and day counters, and its history
+since it was first seen:
+
+- the first and last time seen;
+- the AS number, AS name and country last looked up, and when;
+- total requests, and how many were forwarded and how many refused;
+- bytes in each direction;
+- responses by status class;
+- offences by kind: `limit`, `attack`, `rule_blocked`, `waf_blocked` and
+  `token_refused`.
+
+## `lookups.json`
+
+GeoJS answers, one per line:
+
+- `client`;
+- `asn`, `as_name` and `country`;
+- `answered`: when GeoJS answered;
+- `used`: when the answer was last used.
+
+## `reputation.json`
+
+- the last good copy of each list fetched from a URL, with when it was last
+  tried;
+- each DNS blocklist verdict still in use;
+- AbuseIPDB's scores, and the checks spent today.
+
+## `alerts.json`
+
+- the anomaly counters;
+- the alert cooldowns: for each event and netblock, source, file or anomaly
+  scope, when it was last sent and the count of repeats held back since;
+- the alerts sent and held back in the current hour;
+- the alerts waiting for each destination.

 ## Sizes

-`clients.json` takes about 1 KiB per client, about 20 MiB at the default
-`SWWAF_MAX_TRACKED_CLIENTS`. Written every 15 minutes, that is under 2 GiB of
-disk writes a day. `bans.json` takes about 1.2 KiB per ban, at most about 2.5
-KiB, so about 6 MiB at the default `SWWAF_MAX_BANS`. With a full file, a hundred
-new bans a day come to about 600 MiB of writes. `lookups.json` takes about 150
-bytes per answer, under 1.5 GiB of writes a day when full. The other two files
-are usually a few MiB or less.
-
-## Writing
-
-`bans.json` is written `SWWAF_STATE_WRITE_DELAY` after a ban is made, lifted or
-made permanent. Every file is written every `SWWAF_STATE_COUNTER_INTERVAL`, and
-when `smallwebwaf` stops. Each write goes to a temporary file that then replaces
-the file, so a crash leaves the old file or the new one, whole. Before writing a
-file, `smallwebwaf` takes in any edit you made to it, so your edit is not
-overwritten. A write that fails is logged, raised as a `file_error` alert, and
-tried again at the next write. A hard kill loses what changed since the last
-write:
-
- ban changes from the last `SWWAF_STATE_WRITE_DELAY` (10 seconds);
- everything else from the last `SWWAF_STATE_COUNTER_INTERVAL` (15 minutes):
-    - counts and history, and the counts in ban notes;
-    - GeoJS answers;
-    - reputation verdicts and the AbuseIPDB count;
-    - anomaly counters and alert cooldowns.
-
-## Reading at start
-
-The files are read back. Each client keeps its counts, so a restart gives no one
-a fresh allowance. Each ban keeps refusing until it ends. Counter buckets and
-cache entries whose time has passed are discarded. A missing file is empty
-state. These stop the start, with a message naming the file and the place:
-
- a file that does not parse, or has another `version`;
- an entry without a field it needs;
- a ban whose `cause` is not `limit`, `attack`, `admin` or `crowdsec`;
- a ban whose `expires` is not after its `start`.
-
-## Editing while it runs
-
-`smallwebwaf` watches the directory and takes in your edit of a file as soon as
-you save it. What the file then holds replaces what `smallwebwaf` held for it.
-It tells its own writes from yours by comparing the file with what it last read
-or wrote. A change it made after you opened the file, such as a new ban, is lost
-when you save over it; most editors warn when a file changed on disk while it
-was open. An edit with an error that would stop the start does not stop the
-running `smallwebwaf`. It keeps what it holds. At the file's next write it
-renames your file to `<name>.bad`, writes the file again from memory, and logs
-and alerts the file and the place of the error. Mend the `.bad` file and move it
-back. A file you remove is written again at its next write.
+- `clients.json`: about 1 KiB per client, about 20 MiB at the default
+  `SWWAF_MAX_TRACKED_CLIENTS`. Written every 15 minutes, that is under 2 GiB of
+  disk writes a day.
+- `bans.json`: about 1.2 KiB per ban, at most about 2.5 KiB, so about 6 MiB at
+  the default `SWWAF_MAX_BANS`. Written every 15 minutes, a full file comes to
+  about 600 MiB of writes a day, and a hundred new bans a day add about 600 MiB
+  more.
+- `lookups.json`: about 150 bytes per answer, under 1.5 GiB of writes a day when
+  full.
+- `reputation.json` and `alerts.json`: usually a few MiB or less.
@@ -1,8 +1,8 @@
 // Package alerts sends alerts on bans, on traffic over an anomaly
 // threshold, on a source that fails and on a file with an error to each
 // destination set: to the webhook
-// SWWAF_ALERT_WEBHOOK_URL names, each as one JSON object, as the "Alert
-// webhook schema" section of SPEC.md describes, to the Slack incoming
+// SWWAF_ALERT_WEBHOOK_URL names, each as one JSON object, as "The JSON
+// object" in docs/alerts.md describes, to the Slack incoming
 // webhook SWWAF_ALERT_SLACK_WEBHOOK_URL names, as a message, and to the
 // ntfy topic SWWAF_ALERT_NTFY_URL names. A repeat within
 // SWWAF_ALERT_COOLDOWN is held back, and so is an alert past
@@ -149,11 +149,10 @@ type Params struct {
 }

 // Alert is one alert, as the webhook is sent it and alerts.json holds it,
-// with the fields of the "Alert webhook schema" section of SPEC.md. ASN,
-// ASName and Country are, for a ban, the client's as the ban's notes give
-// them.
+// with the fields of "The JSON object" in docs/alerts.md. ASN, ASName and
+// Country are, for a ban, the client's as the ban's notes give them.
 //
-//nolint:tagliatelle // SPEC.md's alert webhook schema names its fields in snake_case
+//nolint:tagliatelle // docs/alerts.md names the alert's fields in snake_case
 type Alert struct {
 	Instance string       `json:"instance"`
 	Time     time.Time    `json:"time"`
@@ -1,8 +1,8 @@
 // Package anomaly counts requests and bytes over a minute and an hour, per
 // client, per surrounding netblock, per AS number, for the whole service
 // and per named netblock, and raises an anomaly alert for a count over its
-// threshold, as "Anomaly thresholds" under "Configuration surface" in
-// SPEC.md describes. It refuses and bans nothing. At most 20,000 counters
+// threshold, as "Anomaly thresholds" under "Settings" in SPEC.md
+// describes. It refuses and bans nothing. At most 20,000 counters
 // are kept, in memory, and written to alerts.json and read from it by the
 // state package.
 package anomaly
@@ -1,6 +1,7 @@
-// Package metrics keeps smallwebwaf's Prometheus metrics, as the "Metrics
-// endpoint" section of SPEC.md lists them, and serves them in the
-// Prometheus text format. No metric carries a client's address.
+// Package metrics keeps smallwebwaf's Prometheus metrics, as
+// docs/metrics.md lists them, and serves them in the Prometheus text
+// format, as the "Metrics endpoint" section of SPEC.md requires. No
+// metric carries a client's address.
 package metrics

 import (
@@ -206,7 +206,7 @@ type Hit struct {
 // Counts are a client's requests and bytes in the minute, the hour and
 // the day that end at a request, that request's included.
 //
-//nolint:tagliatelle // SPEC.md's request log names its fields in snake_case
+//nolint:tagliatelle // docs/request-log.md names the fields in snake_case
 type Counts struct {
 	Minute      float64 `json:"minute"`
 	Hour        float64 `json:"hour"`
@@ -64,11 +64,10 @@ const LimitHitErrorBurst = "error_burst"
 const timeLayout = "2006-01-02T15:04:05.000Z07:00"

 // Line is one request's line in the request log. The field names, and
-// their order, are those of the "Request log" section of SPEC.md. A field
-// that may not apply to a request is left out of its line when it does
-// not.
+// their order, are those of docs/request-log.md. A field that may not
+// apply to a request is left out of its line when it does not.
 //
-//nolint:tagliatelle // SPEC.md's request log names its fields in snake_case
+//nolint:tagliatelle // docs/request-log.md names the fields in snake_case
 type Line struct {
 	Type string `json:"type"`

@@ -1,5 +1,6 @@
 // Package state keeps smallwebwaf's state in JSON files in
-// SWWAF_STATE_DIR, as the "Persistent state" section of SPEC.md describes:
+// SWWAF_STATE_DIR, as the "Persistent state" section of SPEC.md requires
+// and docs/state-files.md lists them:
 // bans.json holds the bans, clients.json each client's counters and
 // history, lookups.json GeoJS's answers, reputation.json the last try and
 // last good copy of each list fetched from a URL, the DNSBL zones'
@@ -1019,8 +1019,8 @@ func TestEditJustBeforeAScheduledWriteSurvivesIt(t *testing.T) {
 		edit(t, dir, bansJSON, permanentBansJSON)

 		// The write takes the edit in first, and writes it back. The second
-		// ban, made after the admin opened the file, is lost, as "Edits
-		// while running" in SPEC.md says.
+		// ban, made after the admin opened the file, is lost, as the
+		// "Persistent state" section of SPEC.md says.
 		time.Sleep(time.Nanosecond)
 		synctest.Wait()

@@ -1,8 +1,8 @@
 // Package waf runs the OWASP Core Rule Set 4.25.0, through Coraza, on the
 // method, the URL with its query and the headers of a request, and on its
 // body while SWWAF_WAF_BODY_LIMIT is set, with the six changes smallwebwaf
-// makes to it, as "Attack detection" under "Configuration surface" in
-// SPEC.md describes them. It reads no response.
+// makes to it, as "Attack detection" under "Settings" in SPEC.md describes
+// them. It reads no response.
 //
 // smallwebwaf writes only to its state directory, so Coraza is built with
 // its no_fs_access tag, as the Dockerfile and script/build build it: of a
@@ -87,7 +87,7 @@ start_container() {
 # start_moved_container: run the app's container with the state files on
 # a new volume at /srv/state, which SWWAF_STATE_DIR_FILE names in a file
 # only the smallwebwaf user can read, as under "Settings given as files"
-# in README.md, and wait until it is healthy. smallwebwaf can write the
+# in docs/settings.md, and wait until it is healthy. smallwebwaf can write the
 # new volume only once the run script has given it to that user.
 start_moved_container() {
    docker volume create "$MOVED_VOLUME" >/dev/null
@@ -2,11 +2,12 @@
 # script/gitea-requests: build the image and run gitea 1.27.3 behind it,
 # with every setting of smallwebwaf at its default but SWWAF_UPSTREAM_URL,
 # which names gitea's container. Then send through it the gitea requests
-# that reading gitea's source found the Core Rule Set refuses, and a short
-# sample of gitea's ordinary use: signing in, pages of files and commits,
-# a diff, the API, a push, clone and fetch over HTTP, and two container
-# image pushes. Last, print each request smallwebwaf logged, with what it
-# did with it and the ids of the Core Rule Set's rules that matched it.
+# that reading gitea's source found the Core Rule Set refuses, which
+# docs/gitea.md records, and a short sample of gitea's ordinary use:
+# signing in, pages of files and commits, a diff, the API, a push, clone
+# and fetch over HTTP, and two container image pushes. Last, print each
+# request smallwebwaf logged, with what it did with it and the ids of the
+# Core Rule Set's rules that matched it.
 # Every request comes from one client, docker's gateway, so more than
 # SWWAF_ERROR_BURST_THRESHOLD, 30, refusals in a minute would ban it, and
 # the requests after would show as banned. The containers, the network,
Author	SHA1	Message	Date
sneak	a62909dbf4	Last pass: the sixth README review and the fifth SPEC review check / check (push) Canceled after 0s Details The spec names every fault that stops the start, runs step 15 for every request but the health check, and states each of the fourteen repeated requirements once. docs/alerts.md says which alerts have an empty client and netblock and what a summary's detail holds; docs/settings.md lists the settings that need a lookup and points at step 3 for the two static lists. The README and the spec now travel in one branch, so the README never names a spec section that does not exist yet. Model: fable-5-1	2026-10-22 23:02:00 +00:00
sneak	ef03d15ee2	README rewritten from scratch so a newcomer can follow it (closes #154 , closes #155 ) The old README opened with project history and one list of a hundred settings. The new one leads with what smallwebwaf is, what it protects against, how to build and deploy it, what happens to a request, the settings most deployments touch, how to check it works, the entrypoints, the rationale and the design, as REPO_POLICIES.md requires. The reference lists, every setting, the rule file format, the endpoints, the request log's fields, the alert events, the metrics, the state files, the image and the gitea notes, move to files under docs/, each linked from the README, with SPEC.md as the one place for behaviour. Every statement was checked against the code on next. Model: fable-5-1	2026-10-22 22:54:08 +00:00
sneak	23908b0e33	SPEC: false statements fixed, repeats removed, dropped requirements restored check / check (push) Canceled after 0s Details The bounds sentence, the blocklist URL sentence, the deny list sentence, the limit action's scope and the observe mode sentence now say what the code does. Each of the twenty-one requirements the fourth review found twice is stated once, with a link from the other place. The request id header, redirect_uri's case, change 4's reason and the live archive's InRelease files are back. The biased thresholds are defined where they are introduced. The docs files apply the fifth README review's findings and stay identical to the README branch. Model: fable-5-1	2026-10-22 22:35:29 +00:00
sneak	4ea0a975c8	SPEC: the one place for behaviour and reasons; docs/ as lookup lists only check / check (push) Canceled after 0s Details docs/core-rule-set.md, docs/lookup.md, docs/reputation.md and docs/bans.md restated the spec and are folded back into it and removed. The remaining docs files hold only lists: settings with their defaults and value forms, the request log's fields, the metrics, the endpoints, the state files and their contents, the rule file format and default file, the alert events and messages, the image's contents and pins, and the gitea notes. Every behaviour each of them held moves to the spec, said once. The settings groups have the same names in both files. Stale comments in internal/state and script/example-app point at the right places. Model: fable-5-1	2026-10-22 21:51:39 +00:00
sneak	d712bb1496	SPEC: requirements and reasons only, reference material in docs/ check / check (push) Canceled after 0s Details docs/settings.md is now the one settings reference; the spec keeps the conventions, the off list and each group's requirements and reasons, and links to it for the per-setting entries. The endpoint list, the ban notes, the state file contents, the rule file format and the alert object likewise live in docs/ and are linked from the spec. The package list from the README's Design section joins "Architecture". The nine docs files are byte-identical to those on the README branch. Package comments that named "Alert webhook schema", "Request log" and "Metrics endpoint" for their field lists now name the docs files. Model: fable-5-1	2026-10-22 21:08:26 +00:00
sneak	eff99f0b13	SPEC: each requirement once, lists moved to docs/, repeats and sections dropped check / check (push) Canceled after 0s Details Every requirement the second review found in two to five places is now stated once, with links from the other places. "Risks the design has to handle", "Rollout per service" and most of "Architecture" are gone, their two points of their own moved to "Attack detection" and "Anomaly thresholds". The request log's fields, the metrics and the image's contents move to docs/request-log.md, docs/metrics.md and docs/image.md, each linked from the spec. The off rule names SWWAF_LOOKUP_SOURCE and SWWAF_WAF_MODE, the reputation bound is given, and the six Core Rule Set changes are a numbered list. Model: fable-5-1	2026-10-22 20:43:32 +00:00
sneak	e44ba7ee5e	SPEC rework after review: each requirement once, gitea notes to docs/ check / check (push) Canceled after 0s Details Every requirement is stated once, where it belongs, and linked from elsewhere. The notes on gitea move to docs/gitea.md, which script/gitea-requests points at. The list of settings that take off is exact, the non-goal that contradicted the planned item is gone, and the sentences the review named are split or reordered. The package comments in internal/waf and internal/anomaly point at the renamed sections. Model: fable-5-1	2026-10-22 19:43:03 +00:00
sneak	7fb8662e69	SPEC rewritten from scratch, short and plain, built and planned apart (closes #156 ) check / check (push) Canceled after 0s Details The old SPEC opened with a draft status and milestone narrative, said several requirements twice, and ended with a build order that is all built. The new one keeps every requirement the old one states, said once, in short sentences with bulleted lists in place of comma chains. What the code on next does is in the main sections; the two points the old SPEC deferred, sharing bans between instances and RELP, are in a last section, "Planned, not built", each marked as planned. The status line, the milestones and the build order are dropped as history. Where the old SPEC disagreed with the code, the new one follows the code; the PR body lists each such point. Model: fable-5-1	2026-10-22 18:52:51 +00:00