servewaf answers rproxy's question about each request and takes its report (closes #170)

`smallwebwaf servewaf` runs today's checks on the visitor's request each
question carries, answers rproxy, and passes nothing to an app. rproxy reports
every request servewaf answered. A report counts an allowed request's bytes and
writes servewaf's second log line. The table holds a copy of what a report
needs, never the request, so a report cannot reach a request being handled.

Judgement call: a question's body is read before any check; over 64 KiB gets 400.
Judgement call: a report's bytes and durations have ceilings, so they cannot overflow.
Judgement call: a `close` disposition for SWWAF_BAN_RESPONSE=close.

Model: opus-5-5

README.md

@@ -8,8 +8,7 @@ scanners and other abusers before they reach the app.
 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,
+app's answers back.
-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. [`SPEC.md`](SPEC.md) says how `smallwebwaf` behaves and why. The
@@ -18,10 +17,10 @@ reference documents under [`docs/`](docs/) are listed under "Documents" below.
 ## What it protects against
 
 - Scrapers that fetch every page of a site, all day. Rate limiting gives each
-  client 1000 requests a minute, 10,000 an hour and 50,000 a day. Byte limits
+  client 6000 requests a minute, 100,000 an hour and 1,000,000 a day. Byte
-  give it 10 GiB a minute, 20 GiB an hour and 50 GiB a day. A client over a
+  limits give it 4 GiB a minute, 20 GiB an hour and 200 GiB a day. A client over
-  limit is refused and banned. The first ban lasts an hour. Each repeat within a
+  a limit is refused and banned. The first ban lasts an hour. Each repeat within
-  day makes the next ban three times as long. A ban that would last more than
+  a day makes the next ban three times as long. A ban that would last more than
   seven days is permanent.
 - Scanners that probe for secrets, such as `/.env` or `/.git/config`. The
   default rule file bans such a client for seven days at its first probe. Its
@@ -30,8 +29,8 @@ reference 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, runs those rules (step 11 under "What
+  common web attacks. Coraza, a Go engine, runs those rules (see "Attack
-  happens to a request" below). A request the rules take for an attack is
+  detection" in [`SPEC.md`](SPEC.md)). 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;
@@ -142,89 +141,32 @@ while working on it, see "Entrypoints" below.
 
 ## What happens to a request
 
-Two terms recur below. A clear sign of attack is a request that matches a rule
+`smallwebwaf` handles each request in fifteen steps, in this order. Once a step
-whose action is `ban`, or asks for a trap path (steps 9 and 10). An offence is a
+refuses a request, the steps after it are skipped, apart from step 15, and
-request that counts against its client in its history. It is one of:
+nothing of the request reaches the app. "What happens to a request" in
+[`SPEC.md`](SPEC.md) gives each step in full, under the same numbers.
 
-- a clear sign of attack;
+1. The health check, `GET /_smallwebwaf/healthz`, is answered at once.
-- a broken limit;
+2. The client is identified.
-- a refusal by a rule, by the Core Rule Set or for a missing or wrong token.
+3. The static lists, `SWWAF_ALLOW_NETS` and `SWWAF_DENY_NETS`.
+4. The bans.
+5. The lookup of the client's AS number and country.
+6. The country lists.
+7. The reputation sources.
+8. The client's limit percentage.
+9. The rate limits.
+10. The trap paths.
+11. The rule files.
+12. The Core Rule Set.
+13. `smallwebwaf`'s own endpoints, under `/_smallwebwaf/`.
+14. The request is passed to the app.
+15. After the answer: the byte limits, the error burst and the client's history.
 
-`smallwebwaf` handles each request in this order. A request one step refuses
+A refused visitor is answered with `SWWAF_BAN_RESPONSE`, `403` by default (see
-skips the steps after it, apart from step 13. Nothing of a refused request
+"Ban lengths, response and scope" in [`SPEC.md`](SPEC.md)). A `block` rule or a
-reaches the app. "What happens to a request" in [`SPEC.md`](SPEC.md) gives each
+Core Rule Set match answers `403`. A missing or wrong token gets `401`. A
-step in full.
+request over a size or time limit gets the status for that limit, such as `413`
-
+for a body too large (see "Size and time limits" in [`SPEC.md`](SPEC.md)).
-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
 
@@ -233,8 +175,11 @@ Each setting is an environment variable of the app's container, such as
 [`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,
+- `SWWAF_MODE=observe`: `smallwebwaf` makes no ban of its own, and refuses a
-  ban no one. For trying a configuration.
+  request only for a size or time limit or a missing or wrong token. A request
+  it would have refused is passed to the app, and its log line says what
+  `enforce` mode would have done. For trying a configuration before enforcing
+  it.
 - `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
@@ -376,54 +321,41 @@ nixpkgs fixed at one release. An app's `Dockerfile` installs a package with
 [`docs/image.md`](docs/image.md) lists what the image holds and how each part is
 pinned.
 
-- The container's first process is `runsvinit`, which starts runit, a service
+- runit, a service supervisor, runs `smallwebwaf` and the app side by side, each
-  supervisor. runit runs the `run` script of each directory under
+  as its own user, and starts either again when it exits. The app cannot touch
-  `/etc/service`, and runs it again a second after its program exits.
+  the state files or the process of `smallwebwaf`.
-  `smallwebwaf` runs as the `smallwebwaf` user (uid 65532) and the app as a user
+- `smallwebwaf` listens on port 8080 and passes requests to the app on
-  of its own. So the app cannot touch the state files or the process of
+  `127.0.0.1:8081`. The app listens on `127.0.0.1` only, so nothing reaches it
-  `smallwebwaf`.
+  except through `smallwebwaf`. `smallwebwaf`'s own endpoints are under
-- `smallwebwaf` listens on port 8080, on every address. traefik sends the app's
+  `/_smallwebwaf/`, on the same port.
-  requests there. `smallwebwaf` passes them to the app on `127.0.0.1:8081`. The
+- The app sees the headers traefik sent, with traefik's address added to
-  app listens on `127.0.0.1` only, so nothing reaches it except through
+  `X-Forwarded-For`, from a TCP peer on `127.0.0.1`. So the app must trust
-  `smallwebwaf`. The health check, the metrics and the ban management are on the
+  `127.0.0.1` and `::1` for forwarded headers, besides the private address
-  same port, under `/_smallwebwaf/`. A request for that prefix never reaches the
+  ranges.
-  app.
+- Both processes start with the container's environment variables, so every
-- The app sees what it would see from traefik directly: the same `Host`, the
+  setting of `smallwebwaf` starts with `SWWAF_`, and the app can read a token
-  same `X-Forwarded-Proto`, and `X-Forwarded-For` with traefik's address added
+  given as one. A token given as a file that only the `smallwebwaf` user can
-  at the end. The app's TCP peer is `smallwebwaf` on `127.0.0.1`. So the app
+  read is out of its reach (see "Settings given as files" in
-  must trust `127.0.0.1` and `::1` for forwarded headers, besides the private
-  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
-  environment variable is readable by the app. A token given as a file that only
-  the `smallwebwaf` user can read is not (see "Settings given as files" in
   [`docs/settings.md`](docs/settings.md)).
-- The state files live in `/var/lib/smallwebwaf`. Without a volume there, they
+- The state files live in `/var/lib/smallwebwaf`. A volume mounted there keeps
-  survive a restart of the container and are lost when a deploy replaces it. The
+  them across a deploy.
-  `run` script gives that directory and every file in it to the `smallwebwaf`
+- `smallwebwaf servewaf` runs the same checks for the sites that ask it about
-  user at each start, so a host directory mounted there needs no change of
+  each request, and passes nothing to an app (see "`servewaf`" in
-  owner.
+  [`SPEC.md`](SPEC.md)).
-- The image's health check passes while `smallwebwaf` answers
+- `docker stop` stops both processes at once. `smallwebwaf` gives the requests
-  `GET /_smallwebwaf/healthz` and the app accepts connections. traefik sends a
+  in progress five seconds to finish, so the app must keep answering for five
-  container no requests until it is healthy.
-- When `smallwebwaf` or the app exits, runit starts it again a second later. The
-  other process keeps running. While either is down, the client gets `502`. A
-  `smallwebwaf` that stops at start, as on an invalid setting, is started again
-  every second until the cause is fixed, and logs its message each time.
-- `docker stop` has runit send `SIGTERM` to both processes at once.
-  `smallwebwaf` gives the requests in progress five seconds to finish and writes
-  its state files. To let them finish, the app must keep answering for five
   seconds after `SIGTERM`.
 
-"Deployment" in [`SPEC.md`](SPEC.md) has the rest: moving `smallwebwaf` to
+"Deployment" in [`SPEC.md`](SPEC.md) has the rest: the health check, what
-another port, the health check's timing, and the forwarded headers.
+happens when a process stops, moving `smallwebwaf` to another port, and the
-"Architecture" in [`SPEC.md`](SPEC.md) lists the packages and what each does.
+forwarded headers. "Architecture" in [`SPEC.md`](SPEC.md) lists the packages and
+what each does.
 
 ## TODO
 
 - Planned, as "Planned, not built" in [`SPEC.md`](SPEC.md) describes:
+    - `smallwebwaf rproxy`, the reverse proxy in front of each app that asks
+      `smallwebwaf servewaf` about each request;
     - sharing bans between the instances of several apps;
     - sending the log over RELP.
 

docs/admin-endpoints.md

@@ -2,7 +2,8 @@
 
 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.
+and how their tokens work. `smallwebwaf servewaf` answers them at its own
+address, without those checks (see "`servewaf`" in [`SPEC.md`](../SPEC.md)).
 
 - `GET /_smallwebwaf/healthz`: `200` and `ok`, to anyone.
 - `GET /_smallwebwaf/metrics`: the metrics, for `SWWAF_METRICS_TOKEN` (see

docs/alerts.md

@@ -42,7 +42,7 @@ on one line:
     "asn": "",
     "as_name": "",
     "country": "",
-    "reason": "requests per minute over the limit of 1000",
+    "reason": "requests per minute over the limit of 6000",
     "detail": {
         "ban_expires": "2026-10-06T13:00:00.123Z",
         "cause": "limit",
@@ -51,9 +51,9 @@ on one line:
             "as_name": "",
             "country": "",
             "kind": "requests",
-            "limit": 1000,
+            "limit": 6000,
             "window": "minute",
-            "count": 1001,
+            "count": 6001,
             "request": {
                 "time": "2026-10-06T12:00:00.123456789Z",
                 "method": "GET",
@@ -62,7 +62,7 @@ on one line:
                 "status": 403,
                 "user_agent": "scraper/1.0"
             },
-            "requests": 5210,
+            "requests": 8210,
             "refused": 0,
             "earlier_bans": {
                 "limit": 0,
@@ -78,17 +78,21 @@ on one line:
 
 - `instance`: `SWWAF_INSTANCE_NAME`. `time`: when the alert was raised. `event`:
   one of the events above.
+- `host`: the site of the request that raised the alert. Only `servewaf` sends
+  this field, since it serves many sites, and not for `source_failure`,
+  `file_error` and `summary`.
 - `client`: the address whose request raised the alert. Empty for
-  `source_failure` and `file_error`.
+  `source_failure`, `file_error` and `summary`.
-- `netblock`: empty for `source_failure` and `file_error`; otherwise one of:
+- `netblock`: empty for `source_failure`, `file_error` and `summary`; otherwise
+  one of:
     - the ban's netblock;
-    - the netblock an anomaly counted;
+    - 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`.
+  `requests per minute over the limit of 6000` or `listed by a blocklist`.
 - `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));
@@ -97,6 +101,8 @@ on one line:
     - 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`;
+    - 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.
@@ -107,7 +113,7 @@ Slack and ntfy get a message with a title and a text. The title is the instance
 and the event, such as `fsn1app1/gitea: ban`. The text is the `reason`, then one
 line for each of these that the alert has:
 
-- the client, the netblock and the country;
+- the host, the client, the netblock and the country;
 - the file, the source, the error and the mode from `detail`;
 - the suppressed repeats, if any.
 

docs/gitea.md

@@ -11,8 +11,10 @@ checked again when gitea or the Core Rule Set changes version.
 
 - SSH access to gitea does not pass through `smallwebwaf` and is not protected
   by it.
-- A clone is a response. It fits the defaults of 30 minutes and 5 GiB for all
+- A clone is a response. It fits the defaults of 30 minutes and 1 GiB unless the
-  but the largest repositories and slowest links.
+  repository is large or the link slow. A repository whose clone is larger than
+  1 GiB needs `SWWAF_RESPONSE_MAX_BYTES` raised, and the byte limits with it
+  ("Byte limits, per client" in `SPEC.md`).
 - A push is a request, and so is every other upload:
     - a git push;
     - an LFS object;
@@ -30,12 +32,13 @@ checked again when gitea or the Core Rule Set changes version.
   request limits do most of the work there.
 - An Actions runner that reaches gitea through `smallwebwaf` sends requests all
   day. One older than version 0.4 (April 2026) asks for work every 2 seconds,
-  43,200 requests a day, and reports a running job's log and state every second.
+  43,200 requests a day. While it runs a job, it reports the job's log and state
-  So it passes the day limit of 50,000 after about an hour and a quarter of
+  every second instead, two requests a second. So one runner busy all day sends
-  jobs. It is then banned, the job it is running fails, and each repeat within a
+  172,800 requests, under the request limits. Six such runners on one address,
-  day makes the ban longer. Newer runners ask less often, but a busy one, or
+  each busy all day, pass the day limit of 1,000,000 within two days; five stay
-  several on one address, can still pass it. Put the runners' addresses in
+  under it. Their address is then banned, their running jobs fail, and each
-  `SWWAF_RATE_LIMIT_EXEMPT_NETS`.
+  repeat within a day makes the ban longer. Newer runners ask for work less
+  often. Put the runners' addresses in `SWWAF_RATE_LIMIT_EXEMPT_NETS`.
 
 ## What the Core Rule Set lets through
 

docs/metrics.md

@@ -1,8 +1,17 @@
 # The metrics
 
-The metrics `GET /_smallwebwaf/metrics` answers with, as "Metrics endpoint" in
+What `GET /_smallwebwaf/metrics` answers with. "Metrics endpoint" in
-[`SPEC.md`](../SPEC.md) describes it. Prometheus keeps the `instance` label as
+[`SPEC.md`](../SPEC.md) describes the endpoint. Prometheus keeps the `instance`
-`exported_instance` unless the scrape sets `honor_labels: true`.
+label as `exported_instance` unless the scrape sets `honor_labels: true`.
+
+`smallwebwaf servewaf` counts a denied request at its decision. It counts an
+allowed request when its report comes, with the status, bytes and times the
+report gives. These are not counted:
+
+- a report itself;
+- an allowed request whose report never comes;
+- a question refused with `400`;
+- a question whose body stopped arriving.
 
 ## Traffic
 

docs/request-log.md

@@ -117,3 +117,65 @@ All in milliseconds:
   connection;
 - `duration_upstream_first_byte`: until the first byte of the answer;
 - `duration_upstream_total`: until the end of the answer.
+
+## `servewaf`'s lines
+
+`smallwebwaf servewaf` writes two lines for each question it answers, joined by
+`request_id`. The field `servewaf_line` says which of the two a line is:
+
+- `decision`: the line it writes once it has answered the question;
+- `report`: the line it writes when `rproxy`'s report comes, with everything
+  known. The repetition is intended.
+
+A request to its own endpoints writes one line, without `servewaf_line`. A
+report writes no line but the `report` line of the request it names.
+
+These questions write no line:
+
+- a question refused with `400` (see "The question" under "`servewaf`" in
+  [`SPEC.md`](../SPEC.md));
+- a question whose body stopped arriving, which gets no answer.
+
+### The `decision` line
+
+It has the fields above, with these meanings where they differ:
+
+- `client_ip`: `X-Smallwebwaf-Client`.
+- `peer_ip`: `X-Smallwebwaf-Peer`.
+- `host`: the site the visitor asked for.
+- `protocol`: the question's own, `HTTP/1.1`.
+- `content_length`: `X-Smallwebwaf-Content-Length`.
+- `request_id`: the question's `X-Request-ID`.
+- `status`: what `servewaf` answered: `200` for `allow`, the status of `deny`,
+  or `0` for `close`, as the visitor is then sent nothing.
+- `request_bytes`: how much of the question's body the Core Rule Set read.
+- `response_bytes`: the body of `servewaf`'s answer.
+- `action`: `forward` for `allow`, and `admin` for the `404` for a path under
+  `/_smallwebwaf/`.
+- `aborted`: true when `rproxy` went away before the answer.
+- `duration_total`: from the question's headers being read to the line.
+
+The line leaves out `upstream_status`, `websocket` and the
+`duration_upstream_...` fields, since `servewaf` passes nothing to the app.
+
+The bytes of an allowed request are counted when its report comes. So `counts`
+holds the client's bytes without this request's.
+
+### The `report` line
+
+It has every field of the `decision` line, and `time` stays when the request
+arrived. These fields say what the report says:
+
+- `status`: what the visitor got, `0` if nothing;
+- `request_bytes` and `response_bytes`: the body bytes each way, with what a
+  WebSocket carried each way;
+- `duration_total`: from the request's headers being read by `rproxy` to the end
+  of the answer;
+- `duration_upstream_total`: from the hand-over to the app to the end of the
+  answer, for an allowed request.
+
+For an allowed request, the report's counting also changes these fields:
+
+- `counts`: the byte totals now include this request's;
+- `limit_hit`, `offence` and `ban_expires`: set when the report's bytes broke a
+  byte limit.

docs/settings.md

@@ -4,6 +4,23 @@ 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.
 
+## `servewaf`
+
+`smallwebwaf servewaf` uses every setting here but these, which it ignores:
+
+- `SWWAF_UPSTREAM_URL` and `SWWAF_TRUSTED_PROXIES`;
+- the five timeouts under "Size and time limits";
+- `SWWAF_CLIENT_REQUEST_HEADER_MAX_BYTES`, `SWWAF_REQUEST_MAX_BYTES` and
+  `SWWAF_RESPONSE_MAX_BYTES`.
+
+An invalid value of one of these still stops the start, and the line of settings
+at start still shows them.
+
+`SWWAF_ADD_LOOKUP_HEADERS` puts the headers on the answer to `rproxy`, not on a
+request to an app. `SWWAF_WAF_BODY_LIMIT` has an effect up to 64 KiB less one
+byte, whatever its value. A question carries no more of a body than 64 KiB (see
+"`servewaf`" in [`SPEC.md`](../SPEC.md)).
+
 ## Forms of values
 
 - A duration is Go's syntax, with `d` for days: `90s`, `15m`, `24h`, `7d`. Zero
@@ -91,24 +108,24 @@ that take `off`, the `_FILE` form, and what each group does and why.
 ## Static lists
 
 - `SWWAF_ALLOW_NETS` (default empty): netblocks you trust, such as your
-  monitoring. Their clients are refused only for a size or time limit or a
+  monitoring (see step 3 in [`SPEC.md`](../SPEC.md)).
-  missing or wrong token.
 - `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 always refused.
+- `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`
+- `SWWAF_RATE_LIMIT_PER_MINUTE` (default `6000`), `SWWAF_RATE_LIMIT_PER_HOUR`
-  (default `10000`) and `SWWAF_RATE_LIMIT_PER_DAY` (default `50000`): the most
+  (default `100000`) and `SWWAF_RATE_LIMIT_PER_DAY` (default `1000000`): the
-  requests a client may make in each window. A count or `off`.
+  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`
+- `SWWAF_BYTES_LIMIT_PER_MINUTE` (default `4G`), `SWWAF_BYTES_LIMIT_PER_HOUR`
-  (default `20G`) and `SWWAF_BYTES_LIMIT_PER_DAY` (default `50G`): the most
+  (default `20G`) and `SWWAF_BYTES_LIMIT_PER_DAY` (default `200G`): 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`.
@@ -131,12 +148,18 @@ that take `off`, the `_FILE` form, and what each group does and why.
   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
+- `SWWAF_RESPONSE_MAX_BYTES` (default `1G`): the largest response body. A size
   or `off`.
 
 ## Lookup of AS number and country
 
-- `SWWAF_LOOKUP_SOURCE` (default `geojs`): `geojs`, `file` or `off`.
+- `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
@@ -190,8 +213,7 @@ that take `off`, the `_FILE` form, and what each group does and why.
 - `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
+  in a minute (see "Attack detection" in `SPEC.md`). A count or `off`.
-  token check. A count or `off`.
 
 ## Ban lengths, response and scope
 
@@ -286,7 +308,7 @@ 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 a lookup source.
+- `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
@@ -322,4 +344,5 @@ A few limits are fixed rather than settings:
 - 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;
 - at most 20,000 anomaly counters are kept;
-- each alert destination's queue holds at most 1,000 alerts.
+- each alert destination's queue holds at most 1,000 alerts;
+- `servewaf` holds at most 10,000 answered requests awaiting their reports.

internal/alerts/alerts.go

@@ -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
+// SWWAF_ALERT_WEBHOOK_URL names, each as one JSON object, as "The JSON
-// webhook schema" section of SPEC.md describes, to the Slack incoming
+// 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
@@ -149,15 +149,17 @@ 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,
+// with the fields of "The JSON object" in docs/alerts.md. ASN, ASName and
-// ASName and Country are, for a ban, the client's as the ban's notes give
+// Country are, for a ban, the client's as the ban's notes give them. Host is
-// them.
+// the site of the request that raised the alert, while one servewaf serves
+// many sites, and "" otherwise.
 //
-//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"`
 	Event    string       `json:"event"`
+	Host     string       `json:"host,omitempty"`
 	Client   netip.Addr   `json:"client"`
 	Netblock netip.Prefix `json:"netblock"`
 	ASN      string       `json:"asn"`
@@ -900,12 +902,16 @@ func title(alert *Alert) string {
 }
 
 // text returns the text of alert in Slack and ntfy: its reason, then a
-// line for each of its client, netblock and country, the file, source,
+// line for each of its host, client, netblock and country, the file,
-// error and mode its detail gives, and its suppressed repeats, that it
+// source, error and mode its detail gives, and its suppressed repeats, that
-// has.
+// it has.
 func text(alert *Alert) string {
 	lines := []string{alert.Reason}
 
+	if alert.Host != "" {
+		lines = append(lines, "host: "+alert.Host)
+	}
+
 	if alert.Client.IsValid() {
 		lines = append(lines, "client: "+alert.Client.String())
 	}

internal/alerts/alerts_test.go

@@ -1284,9 +1284,11 @@ func anAlertForEachEvent() []eventMessage {
 				Event: alerts.EventWAFBlock, Client: netip.MustParseAddr("192.0.2.1"),
 				Netblock: netip.MustParsePrefix("192.0.2.1/32"),
 				Reason:   "refused by the Core Rule Set",
+				Host:     "app.example",
 			},
 			"fsn1app1/gitea: waf_block", "default shield",
-			"refused by the Core Rule Set\nclient: 192.0.2.1\nnetblock: 192.0.2.1/32",
+			"refused by the Core Rule Set\nhost: app.example\nclient: 192.0.2.1\n" +
+				"netblock: 192.0.2.1/32",
 		},
 		{
 			alerts.Alert{

internal/anomaly/anomaly.go

@@ -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
+// threshold, as "Anomaly thresholds" under "Settings" in SPEC.md
-// SPEC.md describes. It refuses and bans nothing. At most 20,000 counters
+// 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
@@ -103,6 +103,8 @@ type Counter struct {
 
 // Request is a request that has ended, as the counters count it.
 type Request struct {
+	// Host is the site the alert names, "" for none.
+	Host string
 	// Client is the client's address, and ClientGroup the client it is
 	// counted as: its IPv4 address, or the IPv6 netblock of
 	// SWWAF_IPV6_GROUP_PREFIX its address is in.
@@ -396,6 +398,7 @@ func alertFor(r Request, k key, o overThreshold) alerts.Alert {
 
 	return alerts.Alert{
 		Event:    alerts.EventAnomaly,
+		Host:     r.Host,
 		Client:   r.Client,
 		Netblock: k.netblock,
 		ASN:      r.ASN,

internal/config/config.go

@@ -502,17 +502,17 @@ func FromEnvironment(lookupEnv func(string) (string, bool)) (*Config, error) {
 		UpstreamRequestTimeout:  env.duration("SWWAF_UPSTREAM_REQUEST_TIMEOUT", "60s"),
 		UpstreamResponseTimeout: env.duration("SWWAF_UPSTREAM_RESPONSE_TIMEOUT", "30m"),
 		RequestMaxBytes:         env.size("SWWAF_REQUEST_MAX_BYTES", "100M"),
-		ResponseMaxBytes:        env.size("SWWAF_RESPONSE_MAX_BYTES", "5G"),
+		ResponseMaxBytes:        env.size("SWWAF_RESPONSE_MAX_BYTES", "1G"),
 		AllowNets:               env.netblocks("SWWAF_ALLOW_NETS", ""),
 		RateLimitExemptNets:     env.netblocks("SWWAF_RATE_LIMIT_EXEMPT_NETS", ""),
 		DenyNets:                env.netblocks("SWWAF_DENY_NETS", ""),
-		RateLimitPerMinute:      env.count("SWWAF_RATE_LIMIT_PER_MINUTE", "1000"),
+		RateLimitPerMinute:      env.count("SWWAF_RATE_LIMIT_PER_MINUTE", "6000"),
-		RateLimitPerHour:        env.count("SWWAF_RATE_LIMIT_PER_HOUR", "10000"),
+		RateLimitPerHour:        env.count("SWWAF_RATE_LIMIT_PER_HOUR", "100000"),
-		RateLimitPerDay:         env.count("SWWAF_RATE_LIMIT_PER_DAY", "50000"),
+		RateLimitPerDay:         env.count("SWWAF_RATE_LIMIT_PER_DAY", "1000000"),
 		RateLimitExemptPaths:    env.pathPrefixes("SWWAF_RATE_LIMIT_EXEMPT_PATHS", ""),
-		BytesLimitPerMinute:     env.size("SWWAF_BYTES_LIMIT_PER_MINUTE", "10G"),
+		BytesLimitPerMinute:     env.size("SWWAF_BYTES_LIMIT_PER_MINUTE", "4G"),
 		BytesLimitPerHour:       env.size("SWWAF_BYTES_LIMIT_PER_HOUR", "20G"),
-		BytesLimitPerDay:        env.size("SWWAF_BYTES_LIMIT_PER_DAY", "50G"),
+		BytesLimitPerDay:        env.size("SWWAF_BYTES_LIMIT_PER_DAY", "200G"),
 		BytesCount:              env.bytesCount("SWWAF_BYTES_COUNT", "both"),
 		LookupSource:            env.lookupSource("SWWAF_LOOKUP_SOURCE", "geojs"),
 		LookupDBPath:            env.value("SWWAF_LOOKUP_DB_PATH", ""),

internal/config/config_test.go

@@ -261,10 +261,10 @@ func TestDefaults(t *testing.T) {
 		UpstreamRequestTimeout:      time.Minute,
 		UpstreamResponseTimeout:     30 * time.Minute,
 		RequestMaxBytes:             100 << 20,
-		ResponseMaxBytes:            5 << 30,
+		ResponseMaxBytes:            1 << 30,
-		RateLimitPerMinute:          1000,
+		RateLimitPerMinute:          6000,
-		RateLimitPerHour:            10000,
+		RateLimitPerHour:            100000,
-		RateLimitPerDay:             50000,
+		RateLimitPerDay:             1000000,
 		BanResponse:                 403,
 		LimitBanDuration:            time.Hour,
 		LimitBanRepeatWindow:        24 * time.Hour,
@@ -284,8 +284,8 @@ func TestDefaults(t *testing.T) {
 		LookupSource: defaultLookupSource, LookupTimeout: time.Second,
 	})
 	wantByteLimitSettings(t, cfg, config.Config{
-		BytesLimitPerMinute: 10 << 30, BytesLimitPerHour: 20 << 30,
+		BytesLimitPerMinute: 4 << 30, BytesLimitPerHour: 20 << 30,
-		BytesLimitPerDay: 50 << 30, BytesCount: "both",
+		BytesLimitPerDay: 200 << 30, BytesCount: "both",
 	})
 
 	if cfg.UpstreamURL.String() != "http://127.0.0.1:8081" {
@@ -2371,17 +2371,17 @@ func TestLogsEachSettingWithItsValue(t *testing.T) {
 		upstreamRequestTimeout:  "60s",
 		upstreamResponseTimeout: "30m",
 		requestMaxBytes:         "100M",
-		responseMaxBytes:        "5G",
+		responseMaxBytes:        "1G",
 		allowNets:               "",
 		rateLimitExemptNets:     "",
 		denyNets:                "",
-		rateLimitPerMinute:      "1000",
+		rateLimitPerMinute:      "6000",
-		rateLimitPerHour:        "10000",
+		rateLimitPerHour:        "100000",
-		rateLimitPerDay:         "50000",
+		rateLimitPerDay:         "1000000",
 		rateLimitExemptPaths:    "",
-		bytesLimitPerMinute:     "10G",
+		bytesLimitPerMinute:     "4G",
 		bytesLimitPerHour:       "20G",
-		bytesLimitPerDay:        "50G",
+		bytesLimitPerDay:        "200G",
 		bytesCount:              "both",
 		lookupSource:            defaultLookupSource,
 		lookupDBPath:            "",

internal/metrics/metrics.go

@@ -1,6 +1,7 @@
-// Package metrics keeps smallwebwaf's Prometheus metrics, as the "Metrics
+// Package metrics keeps smallwebwaf's Prometheus metrics, as
-// endpoint" section of SPEC.md lists them, and serves them in the
+// docs/metrics.md lists them, and serves them in the Prometheus text
-// Prometheus text format. No metric carries a client's address.
+// format, as the "Metrics endpoint" section of SPEC.md requires. No
+// metric carries a client's address.
 package metrics
 
 import (
@@ -402,28 +403,21 @@ func (m *Metrics) RequestEnded(
 	line *requestlog.Line, limit string, duration, upstreamDuration time.Duration,
 ) {
 	m.inFlight.Dec()
+	m.count(line, limit, duration, upstreamDuration)
+}
 
-	class := statusClass(line.Status)
+// RequestAllowed counts a question of rproxy's, answered allow, as no longer
-	m.requests.WithLabelValues(class, line.Action).Inc()
+// under way. RequestReported counts the request it was about.
-	m.requestBytes.WithLabelValues(class, line.Action).Add(float64(line.RequestBytes))
+func (m *Metrics) RequestAllowed() {
-	m.responseBytes.WithLabelValues(class, line.Action).Add(float64(line.ResponseBytes))
+	m.inFlight.Dec()
-	m.requestDuration.Observe(duration.Seconds())
+}
 
-	if upstreamDuration > 0 {
+// RequestReported counts a request rproxy passed to the app, as RequestEnded
-		m.upstreamDuration.Observe(upstreamDuration.Seconds())
+// does, from what its report says, which line holds.
-	}
+func (m *Metrics) RequestReported(
-
+	line *requestlog.Line, duration, upstreamDuration time.Duration,
-	if limit != "" {
+) {
-		m.sizeAndTimeLimitHits.WithLabelValues(limit).Inc()
+	m.count(line, "", duration, upstreamDuration)
-	}
-
-	if line.Country != "" {
-		m.countries.add(line.Country, line)
-	}
-
-	if line.ASN != "" {
-		m.asns.add(line.ASN, line)
-	}
 }
 
 // LimitHit counts a request that broke a rate limit, a byte limit or the
@@ -492,6 +486,33 @@ func (m *Metrics) StateFileEditSetAside(name string) {
 	m.stateFileEditsSetAside.WithLabelValues(name).Inc()
 }
 
+// count counts a request that has ended, as RequestEnded describes.
+func (m *Metrics) count(
+	line *requestlog.Line, limit string, duration, upstreamDuration time.Duration,
+) {
+	class := statusClass(line.Status)
+	m.requests.WithLabelValues(class, line.Action).Inc()
+	m.requestBytes.WithLabelValues(class, line.Action).Add(float64(line.RequestBytes))
+	m.responseBytes.WithLabelValues(class, line.Action).Add(float64(line.ResponseBytes))
+	m.requestDuration.Observe(duration.Seconds())
+
+	if upstreamDuration > 0 {
+		m.upstreamDuration.Observe(upstreamDuration.Seconds())
+	}
+
+	if limit != "" {
+		m.sizeAndTimeLimitHits.WithLabelValues(limit).Inc()
+	}
+
+	if line.Country != "" {
+		m.countries.add(line.Country, line)
+	}
+
+	if line.ASN != "" {
+		m.asns.add(line.ASN, line)
+	}
+}
+
 // addReputationQueries adds the counter of the queries to source, a DNSBL
 // zone, or of the checks of clients with AbuseIPDB, which count tells.
 func (m *Metrics) addReputationQueries(source prometheus.Labels, count func() int) {

internal/proxy/admin.go

@@ -41,6 +41,15 @@ var (
 	errNotAddress = errors.New("is not an address, such as 203.0.113.9")
 )
 
+// answerHealth answers a request for the health endpoint.
+func (rq *request) answerHealth() {
+	rq.line.Action = requestlog.ActionAdmin
+	// Set here rather than left to Go's server, which would set it only
+	// after the log line has taken the response's headers.
+	rq.out.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	_, _ = io.WriteString(rq.out, "ok\n")
+}
+
 // answerAdmin answers a request for smallwebwaf itself, under
 // /_smallwebwaf/, once it has passed the checks. Each endpoint needs a
 // token, sent as Authorization: Bearer <token>: the metrics

internal/proxy/anomaly_internal_test.go

@@ -15,9 +15,11 @@ func TestWithEveryAnomalyThresholdOffARequestIsNotCounted(t *testing.T) {
 	// anomaly counters, nor a clock, and the request no response: reading
 	// any of them to count the request panics.
 	rq := &request{
-		h:        &handler{config: &config.Config{LookupSource: "geojs"}},
+		decision: decision{
-		client:   netip.MustParseAddr("203.0.113.9"),
+			client:   netip.MustParseAddr("203.0.113.9"),
-		lookedUp: true,
+			lookedUp: true,
+		},
+		h: &handler{config: &config.Config{LookupSource: "geojs"}},
 	}
 
 	defer func() {

internal/proxy/bans.go

@@ -323,6 +323,7 @@ func (rq *request) alertBan(ban bans.Ban) {
 
 	rq.h.alerts.Raise(alerts.Alert{
 		Event:    event,
+		Host:     rq.site,
 		Client:   rq.client,
 		Netblock: ban.Netblock,
 		ASN:      ban.Notes.ASN,
@@ -339,11 +340,11 @@ func (rq *request) alertBan(ban bans.Ban) {
 func (rq *request) noted(now time.Time, status int) bans.Request {
 	return bans.Request{
 		Time:      now,
-		Method:    rq.in.Method,
+		Method:    rq.line.Method,
-		Host:      rq.in.Host,
+		Host:      rq.line.Host,
-		Path:      rq.in.URL.RequestURI(),
+		Path:      rq.requestURI,
 		Status:    status,
-		UserAgent: rq.in.UserAgent(),
+		UserAgent: rq.line.UserAgent,
 	}
 }
 

internal/proxy/bans_test.go

@@ -25,6 +25,8 @@ const (
 	userAgent = "ban-test/1.0"
 	// permanent is the log line's ban_expires for a permanent ban.
 	permanent = "permanent"
+	// banResponseClose is the SWWAF_BAN_RESPONSE that closes the connection.
+	banResponseClose = "close"
 )
 
 func TestBrokenLimitBansTheClient(t *testing.T) {
@@ -237,7 +239,7 @@ func TestBanResponseAnswersEveryRefusalButTheSizeLimits(t *testing.T) {
 		{"", http.StatusForbidden},
 		{"403", http.StatusForbidden},
 		{"429", http.StatusTooManyRequests},
-		{"close", 0},
+		{banResponseClose, 0},
 	} {
 		t.Run(banResponse+"="+tc.setting, func(t *testing.T) {
 			t.Parallel()

internal/proxy/coreruleset.go

@@ -113,6 +113,7 @@ func (rq *request) alertWAFBlock(result waf.Result) {
 
 	rq.h.alerts.Raise(alerts.Alert{
 		Event:    alerts.EventWAFBlock,
+		Host:     rq.site,
 		Client:   rq.client,
 		Netblock: rq.h.clientGroup(rq.client),
 		ASN:      rq.line.ASN,

internal/proxy/metrics_test.go

@@ -207,7 +207,7 @@ func TestMetricsCountLimitsAndBans(t *testing.T) {
 		rateLimitPerMinute:  "1",
 		rateLimitExemptNets: scraper,
 		denyNets:            denied,
-		banResponse:         "close",
+		banResponse:         banResponseClose,
 		limitBanDuration:    "1h",
 		maxBanDuration:      "2h",
 	})

internal/proxy/proxy.go

@@ -1,6 +1,8 @@
-// Package proxy passes each request to the app and the app's answer back,
+// Package proxy runs the checks on each request and writes its request log
-// unchanged, within the size and time limits, and writes one request log
+// line. New passes each request it lets through to the app and the app's
-// line for each request.
+// answer back, unchanged, within the size and time limits. NewServeWAF instead
+// answers rproxy's question about each request, and takes rproxy's report once
+// the visitor's answer has ended, which writes the request a second log line.
 package proxy
 
 import (
@@ -11,6 +13,8 @@ import (
 	"strings"
 	"time"
 
+	lru "github.com/hashicorp/golang-lru/v2"
+
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
 	"sneak.berlin/go/smallwebwaf/internal/anomaly"
 	"sneak.berlin/go/smallwebwaf/internal/bans"
@@ -19,7 +23,6 @@ import (
 	"sneak.berlin/go/smallwebwaf/internal/metrics"
 	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
-	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 	"sneak.berlin/go/smallwebwaf/internal/rules"
 	"sneak.berlin/go/smallwebwaf/internal/waf"
 )
@@ -53,7 +56,8 @@ const ClientsPath = "/_smallwebwaf/clients/"
 // Params are what New needs.
 type Params struct {
 	Config *config.Config
-	// RequestLog receives one JSON line per request.
+	// RequestLog receives one JSON line per request, and from servewaf a second
+	// when the request's report comes.
 	RequestLog io.Writer
 	// ProcessLog receives the process's own messages.
 	ProcessLog *slog.Logger
@@ -109,6 +113,23 @@ type Server struct {
 // SWWAF_CLIENT_REQUEST_TIMEOUT while the headers arrive; the proxy
 // applies the timeouts and size limits from then on.
 func New(params Params) *Server {
+	h := newHandler(params)
+
+	return h.server(&http.Server{
+		Handler:           h,
+		ReadHeaderTimeout: params.Config.ClientRequestTimeout,
+		// Off is an IdleTimeout of 0, which Go's server replaces with
+		// ReadTimeout: no limit, as long as ReadTimeout stays unset.
+		IdleTimeout: params.Config.ClientIdleTimeout,
+		// Go's server reads 4 KiB past MaxHeaderBytes before it
+		// refuses, so the limit a client meets is the setting.
+		MaxHeaderBytes: int(params.Config.ClientRequestHeaderMaxBytes - 4<<10),
+	})
+}
+
+// newHandler returns the handler with what every request shares, as the
+// settings in params make it.
+func newHandler(params Params) *handler {
 	errorLog := slog.NewLogLogger(params.ProcessLog.Handler(), slog.LevelWarn)
 	m := metrics.New(params.Config.MetricsTopN, params.Config.InstanceName)
 	lists, dnsbl, abuseIPDB := newReputation(params, m)
@@ -171,29 +192,7 @@ func New(params Params) *Server {
 	m.AddBansAndClients(h.ledger, h.limiter, params.Now)
 	m.AddRules(params.Rules)
 
-	return &Server{
+	return h
-		Server: &http.Server{
-			Addr:              params.Config.ListenAddr,
-			Handler:           h,
-			ReadHeaderTimeout: params.Config.ClientRequestTimeout,
-			// Off is an IdleTimeout of 0, which Go's server replaces with
-			// ReadTimeout: no limit, as long as ReadTimeout stays unset.
-			IdleTimeout: params.Config.ClientIdleTimeout,
-			// Go's server reads 4 KiB past MaxHeaderBytes before it
-			// refuses, so the limit a client meets is the setting.
-			MaxHeaderBytes: int(params.Config.ClientRequestHeaderMaxBytes - 4<<10),
-			ErrorLog:       errorLog,
-		},
-		Ledger:     h.ledger,
-		Limiter:    h.limiter,
-		GeoJS:      h.geojs,
-		Anomalies:  h.anomalies,
-		LookupFile: h.lookupFile,
-		Lists:      h.lists,
-		DNSBL:      h.dnsbl,
-		AbuseIPDB:  h.abuseIPDB,
-		Metrics:    m,
-	}
 }
 
 // newReputation returns the lists fetched from URLs, the DNSBL zones'
@@ -274,6 +273,10 @@ type handler struct {
 	rules       *rules.Files
 	coreRuleSet *waf.CoreRuleSet
 	alerts      *alerts.Queue
+	// awaitingReport holds, in servewaf, the decision on each answered
+	// question by its id until its report comes, and nil for a question still
+	// being handled.
+	awaitingReport *lru.Cache[string, *decision]
 }
 
 // newTransport returns what carries requests to the app. It never goes
@@ -299,11 +302,7 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	// The health endpoint is answered at once, before any check, so that
 	// a health checker is never refused. It does not ask the app.
 	if r.Method == http.MethodGet && r.URL.Path == HealthPath {
-		rq.line.Action = requestlog.ActionAdmin
+		rq.answerHealth()
-		// Set here rather than left to Go's server, which would set it only
-		// after the log line has taken the response's headers.
-		rq.out.Header().Set("Content-Type", "text/plain; charset=utf-8")
-		_, _ = io.WriteString(rq.out, "ok\n")
 
 		return
 	}
@@ -339,3 +338,23 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 	rq.forward(r.Context())
 }
+
+// server returns the Server of h, which listens at SWWAF_LISTEN_ADDR and
+// logs through h, with what httpServer sets.
+func (h *handler) server(httpServer *http.Server) *Server {
+	httpServer.Addr = h.config.ListenAddr
+	httpServer.ErrorLog = h.errorLog
+
+	return &Server{
+		Server:     httpServer,
+		Ledger:     h.ledger,
+		Limiter:    h.limiter,
+		GeoJS:      h.geojs,
+		Anomalies:  h.anomalies,
+		LookupFile: h.lookupFile,
+		Lists:      h.lists,
+		DNSBL:      h.dnsbl,
+		AbuseIPDB:  h.abuseIPDB,
+		Metrics:    h.metrics,
+	}
+}

internal/proxy/proxy_test.go

@@ -284,6 +284,16 @@ func newProxy(
 ) (*proxy.Server, *output, *alerts.Queue) {
 	t.Helper()
 
+	return newServerWith(t, proxy.New, appURL, geojsURL, now, env)
+}
+
+// newServerWith is newProxy for the server build makes.
+func newServerWith(
+	t *testing.T, build func(proxy.Params) *proxy.Server,
+	appURL, geojsURL string, now func() time.Time, env map[string]string,
+) (*proxy.Server, *output, *alerts.Queue) {
+	t.Helper()
+
 	settings := map[string]string{
 		"SWWAF_UPSTREAM_URL": appURL, rulesDir: t.TempDir(), instanceName: "app",
 		wafMode: off,
@@ -334,7 +344,7 @@ func newProxy(
 		}
 	}
 
-	server := proxy.New(proxy.Params{
+	server := build(proxy.Params{
 		Config:       cfg,
 		RequestLog:   out,
 		ProcessLog:   processLog,

internal/proxy/reputation.go

@@ -110,6 +110,7 @@ func (rq *request) noteHit(hit bans.ReputationHit, reason string) {
 	rq.h.metrics.ReputationHit(hit.Source)
 	rq.h.alerts.Raise(alerts.Alert{
 		Event:    alerts.EventReputationHit,
+		Host:     rq.site,
 		Client:   rq.client,
 		Netblock: rq.h.clientGroup(rq.client),
 		ASN:      rq.line.ASN,

internal/proxy/request.go

@@ -39,20 +39,20 @@ type refusal struct {
 	limit  string
 }
 
-// request is one request on its way through smallwebwaf, from the moment
+// decision is what the checks note of a request: its log line, and what
-// its headers have been read to its log line.
+// counting the request needs once it has ended. servewaf keeps a copy of it
-type request struct {
+// until the request's report comes. It holds no credentials, since the log line
-	h  *handler
+// never does, and neither the request's objects nor their bodies.
-	in *http.Request
+type decision struct {
-	// rc sets the deadlines of the connection to the client.
+	line   requestlog.Line
-	rc   *http.ResponseController
+	client netip.Addr
-	out  *responseWriter
+	// requestURI is the path with the query, as a ban's notes keep it.
-	body *requestBody // nil for a request without a body
+	requestURI string
-	line requestlog.Line
+	// site is, in servewaf, the host the visitor asked for, which the
-
+	// alerts name, since one servewaf serves many sites. It is "" otherwise.
-	client      netip.Addr
+	site string
-	peer        netip.Addr
+	// allowed is true for a question answered with DispositionAllow.
-	peerTrusted bool
+	allowed bool
 	// lookedUp is true once the client's AS number and country have been
 	// looked up, whether or not an answer was there, and lookupAnswer is
 	// what the lookup gave then, the zero Answer while GeoJS had given none.
@@ -65,18 +65,37 @@ type request struct {
 	counted                    bool
 	limitPercent, bytesPercent percentage
 	// attack is true for a request that matched a ban rule or asked for a
-	// trap path, ruleBlocked for one a block rule refused, wafBlocked for
+	// trap path, ruleBlocked for one a block rule refused, and wafBlocked for
-	// one the Core Rule Set refused, and tokenRefused for one refused for a
+	// one the Core Rule Set refused, each an offence its client's history
-	// missing or wrong token, each an offence its client's history counts.
+	// counts.
-	attack, ruleBlocked, wafBlocked, tokenRefused bool
+	attack, ruleBlocked, wafBlocked bool
+	// reputation is the reputation sources that list the client, for the
+	// notes of a ban the request makes.
+	reputation []bans.ReputationHit
+}
+
+// request is one request on its way through smallwebwaf, from the moment
+// its headers have been read to its log line.
+type request struct {
+	decision
+
+	h  *handler
+	in *http.Request
+	// rc sets the deadlines of the connection to the client.
+	rc   *http.ResponseController
+	out  *responseWriter
+	body *requestBody // nil for a request without a body
+
+	peer        netip.Addr
+	peerTrusted bool
+	// tokenRefused is true for a request refused for a missing or wrong
+	// token, an offence its client's history counts.
+	tokenRefused bool
 	// blocklisted is true once a blocklist is found to list the client,
 	// dnsblListed once a DNSBL zone's verdict is, and abuseIPDBHit once
 	// AbuseIPDB's score of it is a hit.
 	blocklisted, dnsblListed, abuseIPDBHit bool
-	// reputation is the reputation sources that list the client, for the
+	start                                  time.Time
-	// notes of a ban the request makes.
-	reputation []bans.ReputationHit
-	start      time.Time
 	// checked is when the checks were done, and upstreamStart when the
 	// request was handed to the app.
 	checked       time.Time
@@ -108,50 +127,62 @@ type request struct {
 	answerStarted time.Time
 }
 
-// newRequest starts handling r: it notes the time, counts the request as
+// newRequest starts handling r: it works out the client from the TCP peer
-// under way, works out the client, and starts the log line with what is
+// and X-Forwarded-For, and goes on as startRequest does.
-// known of the request.
 func (h *handler) newRequest(w http.ResponseWriter, r *http.Request) *request {
+	peer := peerAddress(r)
+	trusted := h.config.TrustedProxies
+	client := clientAddress(peer, r.Header.Values("X-Forwarded-For"), trusted)
+
+	return h.startRequest(w, r, client, peer, isInside(peer, trusted))
+}
+
+// startRequest starts handling r from client, which came through peer: it
+// notes the time, counts the request as under way, and starts the log line
+// with what is known of the request. peerTrusted says whether to believe
+// the request's id and scheme, which r's headers give.
+func (h *handler) startRequest(
+	w http.ResponseWriter, r *http.Request, client, peer netip.Addr, peerTrusted bool,
+) *request {
 	h.metrics.RequestStarted()
 
 	start := time.Now()
-	peer := peerAddress(r)
-	trusted := h.config.TrustedProxies
-	peerTrusted := isInside(peer, trusted)
 	forwardedFor := r.Header.Values("X-Forwarded-For")
-	client := clientAddress(peer, forwardedFor, trusted)
 
 	rq := &request{
+		decision: decision{
+			client:     client,
+			requestURI: r.URL.RequestURI(),
+			line: requestlog.Line{
+				Time:             requestlog.FormatTime(start),
+				Instance:         h.config.InstanceName,
+				ClientIP:         client.String(),
+				Method:           r.Method,
+				Scheme:           scheme(r, peerTrusted),
+				Host:             r.Host,
+				Path:             rules.Path(r),
+				Query:            r.URL.RawQuery,
+				Protocol:         r.Proto,
+				Referer:          r.Referer(),
+				UserAgent:        r.UserAgent(),
+				RequestID:        requestID(r, peerTrusted),
+				PeerIP:           peer.String(),
+				ForwardedFor:     strings.Join(forwardedFor, ", "),
+				ClientGroup:      h.clientGroup(client).String(),
+				ContentType:      r.Header.Get("Content-Type"),
+				RequestHeaders:   requestHeaders(r, h.config.LogRequestHeaders),
+				HasAuthorization: len(r.Header.Values("Authorization")) > 0,
+				HasCookie:        len(r.Header.Values("Cookie")) > 0,
+				Action:           requestlog.ActionForward,
+			},
+		},
 		h:           h,
 		in:          r,
 		rc:          http.NewResponseController(w),
 		out:         &responseWriter{ResponseWriter: w},
-		client:      client,
 		peer:        peer,
 		peerTrusted: peerTrusted,
 		start:       start,
-		line: requestlog.Line{
-			Time:             requestlog.FormatTime(start),
-			Instance:         h.config.InstanceName,
-			ClientIP:         client.String(),
-			Method:           r.Method,
-			Scheme:           scheme(r, peerTrusted),
-			Host:             r.Host,
-			Path:             rules.Path(r),
-			Query:            r.URL.RawQuery,
-			Protocol:         r.Proto,
-			Referer:          r.Referer(),
-			UserAgent:        r.UserAgent(),
-			RequestID:        requestID(r, peerTrusted),
-			PeerIP:           peer.String(),
-			ForwardedFor:     strings.Join(forwardedFor, ", "),
-			ClientGroup:      h.clientGroup(client).String(),
-			ContentType:      r.Header.Get("Content-Type"),
-			RequestHeaders:   requestHeaders(r, h.config.LogRequestHeaders),
-			HasAuthorization: len(r.Header.Values("Authorization")) > 0,
-			HasCookie:        len(r.Header.Values("Cookie")) > 0,
-			Action:           requestlog.ActionForward,
-		},
 	}
 
 	// A length of -1 is a body whose length was not announced.
@@ -569,10 +600,20 @@ func (rq *request) finish() {
 	}
 
 	// Counted before the log line is written, so that the metrics count
-	// every request whose line is out.
+	// every request whose line is out. An allowed request is the exception:
-	rq.h.metrics.RequestEnded(line, limit, duration, upstreamDuration)
+	// its report gives the status, bytes and times the metrics count.
+	if rq.allowed {
+		rq.h.metrics.RequestAllowed()
+	} else {
+		rq.h.metrics.RequestEnded(line, limit, duration, upstreamDuration)
+	}
 
-	err := requestlog.Write(rq.h.requestLog, line)
+	rq.writeLine()
+}
+
+// writeLine writes the request's log line.
+func (rq *request) writeLine() {
+	err := requestlog.Write(rq.h.requestLog, &rq.line)
 	if err != nil {
 		rq.h.processLog.Error("writing the request log failed", "error", err.Error())
 	}
@@ -634,6 +675,7 @@ func (rq *request) countAnomalies() {
 	answer, _ := rq.answerAtTheEnd()
 
 	rq.h.anomalies.Count(rq.h.now(), anomaly.Request{
+		Host:        rq.site,
 		Client:      rq.client,
 		ClientGroup: rq.h.clientGroup(rq.client),
 		ASN:         answer.ASN,

internal/proxy/servewaf.go

@@ -0,0 +1,464 @@
+package proxy
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/netip"
+	"strconv"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	lru "github.com/hashicorp/golang-lru/v2"
+
+	"sneak.berlin/go/smallwebwaf/internal/requestlog"
+)
+
+// The headers of rproxy's question and of servewaf's answer, as
+// "servewaf" in SPEC.md gives them.
+const (
+	// ClientHeader marks a request as rproxy's question, and gives the
+	// visitor's address.
+	ClientHeader = "X-Smallwebwaf-Client"
+	// PeerHeader gives the address of rproxy's own TCP peer.
+	PeerHeader = "X-Smallwebwaf-Peer"
+	// ContentLengthHeader gives the body length the visitor announced.
+	ContentLengthHeader = "X-Smallwebwaf-Content-Length"
+	// DispositionHeader gives servewaf's answer.
+	DispositionHeader = "X-Smallwebwaf-Disposition"
+)
+
+// The values of DispositionHeader.
+const (
+	// DispositionAllow tells rproxy to pass the request to the app.
+	DispositionAllow = "allow"
+	// DispositionDeny tells rproxy to give the visitor the answer's status,
+	// headers and body.
+	DispositionDeny = "deny"
+	// DispositionClose tells rproxy to close the visitor's connection
+	// without an answer, which SWWAF_BAN_RESPONSE asks for when it is close.
+	// servewaf closing the question's connection instead would read as
+	// servewaf being down, and rproxy would then let the request through.
+	DispositionClose = "close"
+)
+
+// ReportPath is where rproxy sends the report of each request servewaf
+// answered.
+const ReportPath = "/_smallwebwaf/report"
+
+// QuestionBodyMaxBytes is the most of a visitor's body a question carries.
+const QuestionBodyMaxBytes = 64 << 10
+
+const (
+	// maxAwaitingReport is the most answered requests held until their
+	// reports come. Past it, the request answered longest ago is dropped.
+	maxAwaitingReport = 10000
+	// maxRequestIDBytes is the longest id a question may give.
+	maxRequestIDBytes = 128
+	// reportBodyMaxBytes is the most of a report's body that is read. It is
+	// far above any report's.
+	reportBodyMaxBytes = 1 << 20
+	// maxHTTPStatus is the highest status a report may give.
+	maxHTTPStatus = 599
+	// maxReportedBytes is the most bytes a report may give for each way, 1
+	// PiB, so that adding them up cannot overflow.
+	maxReportedBytes = 1 << 50
+	// maxReportedMilliseconds is the longest duration a report may give,
+	// about 31 years, so that it fits a time.Duration.
+	maxReportedMilliseconds = 1e12
+	// serveWAFTimeout bounds how long a request to servewaf takes to arrive,
+	// and its answer to leave, and serveWAFIdleTimeout how long a kept-open
+	// connection waits for its next request.
+	serveWAFTimeout     = 60 * time.Second
+	serveWAFIdleTimeout = 120 * time.Second
+)
+
+var (
+	errReportFieldMissing = errors.New("a field is missing")
+	errReportValue        = errors.New("a value is out of range")
+)
+
+// Report is the JSON object rproxy posts to ReportPath once the visitor's
+// answer has ended, its fields named as the request log's of the same
+// meaning. RequestID is the question's id. Status is what the visitor got, 0
+// if nothing. The durations are in milliseconds.
+//
+//nolint:tagliatelle // docs/request-log.md names the fields in snake_case
+type Report struct {
+	RequestID             string  `json:"request_id"`
+	Status                int     `json:"status"`
+	RequestBytes          int64   `json:"request_bytes"`
+	ResponseBytes         int64   `json:"response_bytes"`
+	DurationTotal         float64 `json:"duration_total"`
+	DurationUpstreamTotal float64 `json:"duration_upstream_total"`
+}
+
+// NewServeWAF returns the server `smallwebwaf servewaf` runs. It answers
+// rproxy's questions with the checks New runs, takes rproxy's reports and
+// answers its own endpoints. It passes nothing to an app. rproxy applies
+// the size and time limits to the visitor, so their settings do not apply
+// here. Go's default limit on a request's line and headers, 1 MiB, stays:
+// it is far above rproxy's, and a question refused for its size would have
+// rproxy let the request through.
+func NewServeWAF(params Params) *Server {
+	cfg := *params.Config
+	cfg.RequestMaxBytes = 0
+	cfg.ClientRequestTimeout = serveWAFTimeout
+	// The server's WriteTimeout does this. It sets a new deadline for each
+	// request, where a deadline a handler sets stays on a kept-open
+	// connection, and would run out under a later request's answer.
+	cfg.ClientResponseTimeout = 0
+	// A question's body of QuestionBodyMaxBytes may be cut short, and the
+	// Core Rule Set does not read a JSON or XML body over its limit.
+	cfg.WAFBodyLimit = min(cfg.WAFBodyLimit, QuestionBodyMaxBytes-1)
+	params.Config = &cfg
+
+	h := newHandler(params)
+
+	awaitingReport, err := lru.New[string, *decision](maxAwaitingReport)
+	if err != nil {
+		panic(err) // New fails only for a size below one
+	}
+
+	h.awaitingReport = awaitingReport
+
+	return h.server(&http.Server{
+		Handler:      http.HandlerFunc(h.serveWAF),
+		ReadTimeout:  serveWAFTimeout,
+		WriteTimeout: serveWAFTimeout,
+		IdleTimeout:  serveWAFIdleTimeout,
+	})
+}
+
+// serveWAF handles one request to servewaf: a request carrying
+// ClientHeader is rproxy's question, and any other is for servewaf itself.
+func (h *handler) serveWAF(w http.ResponseWriter, r *http.Request) {
+	if len(r.Header.Values(ClientHeader)) > 0 {
+		h.answerQuestion(w, r)
+
+		return
+	}
+
+	h.answerOwnEndpoint(w, r)
+}
+
+// answerQuestion runs the checks on the visitor's request a question
+// carries, and answers rproxy what to do with it. A denied request's counting
+// is finished here, and an allowed one's by its report.
+func (h *handler) answerQuestion(w http.ResponseWriter, r *http.Request) {
+	client, body, ok := h.readQuestion(w, r)
+	if !ok {
+		return
+	}
+
+	// One that cannot be read leaves the log line's peer_ip invalid.
+	peer, _ := netip.ParseAddr(r.Header.Get(PeerHeader))
+
+	rq := h.startRequest(w, asTheVisitorSentIt(r, body), client.Unmap(), peer.Unmap(),
+		true)
+	// The last deferred runs first, so that what is held has the finished log
+	// line. Go's server sends the answer only once this function has
+	// returned, so the report cannot come before it is held.
+	defer rq.holdForReport()
+	defer rq.finish()
+
+	rq.site = r.Host
+	rq.line.ServeWAFLine = requestlog.ServeWAFLineDecision
+	refused := rq.check(r.Context())
+	rq.checked = time.Now()
+	underOwnPrefix := strings.HasPrefix(r.URL.Path, adminPrefix)
+
+	if refused == nil && !underOwnPrefix {
+		// In observe mode, what enforce mode would have refused counts here.
+		defer rq.countRefusal()
+
+		rq.allow()
+
+		return
+	}
+
+	// The last deferred runs first, as in ServeHTTP.
+	defer rq.addToHistory()
+	defer rq.countAnomalies()
+	defer rq.countRefusal()
+
+	if refused != nil {
+		rq.deny(*refused)
+
+		return
+	}
+
+	// The app never sees this prefix. servewaf's own endpoints are at its
+	// own address, so this answers as a path with no endpoint does.
+	rq.line.Action = requestlog.ActionAdmin
+	rq.out.Header().Set(DispositionHeader, DispositionDeny)
+	http.Error(rq.out, http.StatusText(http.StatusNotFound), http.StatusNotFound)
+}
+
+// readQuestion returns the visitor's address and the body a question carries,
+// and whether servewaf takes the question. It answers a question it does not
+// take with 400 and no disposition, which rproxy treats as it treats no
+// answer. The id of a question it takes is held from here on, without a
+// decision yet, so that another question with that id is refused while this
+// one is being handled.
+//
+// The body is read before any check, since Go's server does not send an answer
+// until it has read the body. A question whose body stops arriving gets no
+// answer, and is not looked at.
+func (h *handler) readQuestion(
+	w http.ResponseWriter, r *http.Request,
+) (netip.Addr, []byte, bool) {
+	client, err := netip.ParseAddr(r.Header.Get(ClientHeader))
+	if err != nil || client.Zone() != "" {
+		h.refuseQuestion(w, ClientHeader+" is not an address without a zone")
+
+		return netip.Addr{}, nil, false
+	}
+
+	id := r.Header.Get(requestIDHeader)
+	if id == "" || len(id) > maxRequestIDBytes || !utf8.ValidString(id) {
+		h.refuseQuestion(w, requestIDHeader+" is not a valid id")
+
+		return netip.Addr{}, nil, false
+	}
+
+	body, err := io.ReadAll(http.MaxBytesReader(w, r.Body, QuestionBodyMaxBytes))
+
+	if _, tooLarge := errors.AsType[*http.MaxBytesError](err); tooLarge {
+		h.refuseQuestion(w, "the body is over 64 KiB")
+
+		return netip.Addr{}, nil, false
+	}
+
+	if err != nil {
+		h.processLog.Warn("a question's body stopped arriving", "error", err.Error())
+		// This panic has Go's server close the connection without an answer,
+		// and log nothing.
+		panic(http.ErrAbortHandler)
+	}
+
+	held, _ := h.awaitingReport.ContainsOrAdd(id, nil)
+	if held {
+		h.refuseQuestion(w, requestIDHeader+" is the id of a request servewaf holds")
+
+		return netip.Addr{}, nil, false
+	}
+
+	return client, body, true
+}
+
+// refuseQuestion answers a question servewaf does not take, for reason.
+func (h *handler) refuseQuestion(w http.ResponseWriter, reason string) {
+	h.processLog.Warn("a question is refused", "reason", reason)
+	http.Error(w, reason, http.StatusBadRequest)
+}
+
+// asTheVisitorSentIt returns a copy of r, a question, as the checks and the
+// log line are to see it: without the headers rproxy adds for servewaf, with
+// body, which has been read of r, and with the length the visitor announced,
+// as -1 when it announced none. The question's own length covers only the part
+// of the body it carries.
+func asTheVisitorSentIt(r *http.Request, body []byte) *http.Request {
+	sent := r.Clone(r.Context())
+	announced := sent.Header.Get(ContentLengthHeader)
+
+	sent.Header.Del(ClientHeader)
+	sent.Header.Del(PeerHeader)
+	sent.Header.Del(ContentLengthHeader)
+	sent.Header.Del("Content-Length")
+
+	sent.ContentLength = -1
+
+	length, err := strconv.ParseInt(announced, 10, 64)
+	if err == nil && length >= 0 {
+		sent.ContentLength = length
+		sent.Header.Set("Content-Length", announced)
+	}
+
+	sent.Body = http.NoBody
+	if len(body) > 0 {
+		sent.Body = io.NopCloser(bytes.NewReader(body))
+	}
+
+	return sent
+}
+
+// allow answers a question with DispositionAllow and, while
+// SWWAF_ADD_LOOKUP_HEADERS is set, the client's AS number and country.
+func (rq *request) allow() {
+	rq.allowed = true
+
+	header := rq.out.Header()
+	header.Set(DispositionHeader, DispositionAllow)
+
+	if rq.h.config.AddLookupHeaders {
+		setLookupHeaders(header, rq.line.ASN, rq.line.Country)
+	}
+
+	rq.out.WriteHeader(http.StatusOK)
+}
+
+// holdForReport holds a copy of what the report's steps need, by the request's
+// id. A report only ever reaches that copy, never the request being handled.
+func (rq *request) holdForReport() {
+	held := rq.decision
+	rq.h.awaitingReport.Add(rq.line.RequestID, &held)
+}
+
+// deny answers a question with what the visitor is to get for r.
+func (rq *request) deny(r refusal) {
+	if r.status == 0 {
+		// SWWAF_BAN_RESPONSE is close. Written past rq.out, since the log line's
+		// status stays 0: the visitor is sent nothing.
+		rq.refused.CompareAndSwap(nil, &r)
+		rq.out.Header().Set(DispositionHeader, DispositionClose)
+		rq.out.ResponseWriter.WriteHeader(http.StatusOK)
+
+		return
+	}
+
+	rq.out.Header().Set(DispositionHeader, DispositionDeny)
+	rq.answer(r)
+}
+
+// answerOwnEndpoint answers a request to servewaf's own address. No check
+// runs on it: the address is on the private network, where the peers are
+// rproxy and the admin's tools, not visitors.
+func (h *handler) answerOwnEndpoint(w http.ResponseWriter, r *http.Request) {
+	if r.Method == http.MethodPost && r.URL.Path == ReportPath {
+		h.takeReport(w, r)
+
+		return
+	}
+
+	peer := peerAddress(r)
+
+	rq := h.startRequest(w, r, peer, peer, false)
+	defer rq.finish()
+
+	if r.Method == http.MethodGet && r.URL.Path == HealthPath {
+		rq.answerHealth()
+
+		return
+	}
+
+	rq.answerAdmin()
+}
+
+// takeReport answers POST ReportPath: it finishes the request the report
+// names, if it holds that request's decision, and ignores the report
+// otherwise.
+func (h *handler) takeReport(w http.ResponseWriter, r *http.Request) {
+	report, err := readReport(w, r)
+	if err != nil {
+		h.processLog.Warn("a report is refused", "error", err.Error())
+		http.Error(w, "the body is not a report", http.StatusBadRequest)
+
+		return
+	}
+
+	held, found := h.awaitingReport.Peek(report.RequestID)
+	// Remove reports true to one report only, of several that name the id.
+	if found && held != nil && h.awaitingReport.Remove(report.RequestID) {
+		h.finishWith(held, report)
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// readReport reads a report from r's body, which must be one JSON object with
+// all of Report's fields, in the ranges SPEC.md gives.
+func readReport(w http.ResponseWriter, r *http.Request) (Report, error) {
+	var report Report
+
+	body, err := io.ReadAll(http.MaxBytesReader(w, r.Body, reportBodyMaxBytes))
+	if err != nil {
+		return report, fmt.Errorf("read the body: %w", err)
+	}
+
+	var fields map[string]json.RawMessage
+
+	err = json.Unmarshal(body, &fields)
+	if err != nil {
+		return report, fmt.Errorf("decode the body: %w", err)
+	}
+
+	for _, name := range []string{
+		"request_id", "status", "request_bytes", "response_bytes",
+		"duration_total", "duration_upstream_total",
+	} {
+		value, there := fields[name]
+		if !there || string(value) == "null" {
+			return report, fmt.Errorf("%w: %s", errReportFieldMissing, name)
+		}
+	}
+
+	err = json.Unmarshal(body, &report)
+	if err != nil {
+		return report, fmt.Errorf("decode the body: %w", err)
+	}
+
+	return report, report.checkRanges()
+}
+
+// checkRanges returns an error for a value of the report that cannot be true.
+func (report *Report) checkRanges() error {
+	switch {
+	case report.Status != 0 &&
+		(report.Status < http.StatusContinue || report.Status > maxHTTPStatus):
+		return fmt.Errorf("%w: status", errReportValue)
+	case report.RequestBytes < 0 || report.RequestBytes > maxReportedBytes:
+		return fmt.Errorf("%w: request_bytes", errReportValue)
+	case report.ResponseBytes < 0 || report.ResponseBytes > maxReportedBytes:
+		return fmt.Errorf("%w: response_bytes", errReportValue)
+	case report.DurationTotal < 0 || report.DurationTotal > maxReportedMilliseconds:
+		return fmt.Errorf("%w: duration_total", errReportValue)
+	case report.DurationUpstreamTotal < 0 ||
+		report.DurationUpstreamTotal > maxReportedMilliseconds:
+		return fmt.Errorf("%w: duration_upstream_total", errReportValue)
+	}
+
+	return nil
+}
+
+// finishWith finishes a request with what its report says, and writes the
+// request's last log line, which holds its decision's fields and the report's.
+// For an allowed request it first takes the steps ServeHTTP takes once a
+// request passed to the app has ended, with the status and bytes of the report
+// in place of those it would have seen. A denied request's counting was
+// finished at its decision.
+func (h *handler) finishWith(held *decision, report Report) {
+	rq := &request{
+		decision: *held,
+		h:        h,
+		out:      &responseWriter{status: report.Status, bytes: report.ResponseBytes},
+		body:     &requestBody{},
+	}
+	rq.body.bytes.Store(report.RequestBytes)
+
+	rq.line.ServeWAFLine = requestlog.ServeWAFLineReport
+	rq.line.Status = report.Status
+	rq.line.RequestBytes = report.RequestBytes
+	rq.line.ResponseBytes = report.ResponseBytes
+	rq.line.DurationTotal = report.DurationTotal
+
+	if rq.allowed {
+		rq.line.DurationUpstreamTotal = &report.DurationUpstreamTotal
+		// addToHistory goes by this for whether the request reached the app.
+		rq.upstreamStart = time.Now()
+
+		rq.countBytes()
+		rq.countAnomalies()
+		rq.addToHistory()
+
+		rq.h.metrics.RequestReported(&rq.line,
+			time.Duration(report.DurationTotal*float64(time.Millisecond)),
+			time.Duration(report.DurationUpstreamTotal*float64(time.Millisecond)))
+	}
+
+	rq.writeLine()
+}

internal/ratelimit/ratelimit.go

@@ -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"`

internal/requestlog/requestlog.go

@@ -1,6 +1,6 @@
 // Package requestlog writes the lines smallwebwaf prints on stdout: one
-// JSON object per request, marked "type":"request", and the process's own
+// JSON object per request, or two from servewaf, marked "type":"request", and
-// messages as JSON lines marked "type":"process".
+// the process's own messages as JSON lines marked "type":"process".
 package requestlog
 
 import (
@@ -60,17 +60,29 @@ const OffenceLimit = "limit"
 // that broke the error burst.
 const LimitHitErrorBurst = "error_burst"
 
+// The servewaf_line a request line names, which says which of servewaf's two
+// lines about a question it is.
+const (
+	// ServeWAFLineDecision is servewaf's line at its decision.
+	ServeWAFLineDecision = "decision"
+	// ServeWAFLineReport is servewaf's line when rproxy's report comes, with
+	// the decision's fields and the report's together.
+	ServeWAFLineReport = "report"
+)
+
 // timeLayout is RFC 3339 with milliseconds.
 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
+// their order, are those of docs/request-log.md. A field that may not
-// that may not apply to a request is left out of its line when it does
+// apply to a request is left out of its line when it does not.
-// 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"`
+	// ServeWAFLine is ServeWAFLineDecision or ServeWAFLineReport on servewaf's
+	// two lines about a question.
+	ServeWAFLine string `json:"servewaf_line,omitempty"`
 
 	// The standard web log fields. Scheme is how the client reached
 	// smallwebwaf, or the trusted proxy in front of it.

internal/smallwebwaf/healthcheck_test.go

@@ -60,8 +60,19 @@ func TestHealthCheck(t *testing.T) {
 		}, 0, "")
 	}
 
-	app.Close()
+	// Another test can take a closed server's port at once, so the app's
-	wantHealthCheck(t, env, 1, "unhealthy: connect to the app: ")
+	// address here is a multicast address, to which TCP cannot connect.
+	wantHealthCheck(t, map[string]string{
+		listenAddr:  ":" + port,
+		upstreamURL: "http://224.0.0.1",
+	}, 1, "unhealthy: connect to the app: ")
+
+	// Listening on port 0 takes any free port, so nothing listens on port 0
+	// itself.
+	wantHealthCheck(t, map[string]string{listenAddr: ":0"}, 1,
+		"unhealthy: ask smallwebwaf: ")
+	wantHealthCheck(t, map[string]string{listenAddr: "8080"}, 1,
+		"unhealthy: invalid setting: SWWAF_LISTEN_ADDR: ")
 
 	stop()
 
@@ -70,10 +81,6 @@ func TestHealthCheck(t *testing.T) {
 	case <-time.After(waitLimit):
 		t.Fatal("still running after being told to stop")
 	}
-
-	wantHealthCheck(t, env, 1, "unhealthy: ask smallwebwaf: ")
-	wantHealthCheck(t, map[string]string{listenAddr: "8080"}, 1,
-		"unhealthy: invalid setting: SWWAF_LISTEN_ADDR: ")
 }
 
 func TestHealthCheckRefusesAnArgument(t *testing.T) {

internal/smallwebwaf/servewaf_test.go

@@ -0,0 +1,210 @@
+package smallwebwaf_test
+
+import (
+	"context"
+	"crypto/rand"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"syscall"
+	"testing"
+	"time"
+
+	"sneak.berlin/go/smallwebwaf/internal/proxy"
+	"sneak.berlin/go/smallwebwaf/internal/smallwebwaf"
+)
+
+// commandForMain, while set in the environment, has this test binary run Main
+// with the command it gives, in place of the tests, so that a test can run
+// Main in a process of its own.
+const commandForMain = "SMALLWEBWAF_TEST_COMMAND"
+
+func TestMain(m *testing.M) {
+	command, set := os.LookupEnv(commandForMain)
+	if !set {
+		os.Exit(m.Run())
+	}
+
+	os.Args = strings.Fields("smallwebwaf " + command)
+
+	os.Exit(smallwebwaf.Main(testVersion))
+}
+
+func TestMainAnswersQuestionsOnlyAsServeWAF(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range []struct {
+		command, disposition string
+	}{
+		{"servewaf", proxy.DispositionAllow},
+		{"", ""},
+	} {
+		t.Run("command "+tc.command, func(t *testing.T) {
+			t.Parallel()
+
+			binary, err := os.Executable()
+			if err != nil {
+				t.Fatalf("find the test binary: %v", err)
+			}
+
+			ctx, cancel := context.WithTimeout(t.Context(), 3*waitLimit)
+			defer cancel()
+
+			out := &output{}
+			cmd := exec.CommandContext(ctx, binary) //nolint:gosec // this test binary
+			cmd.Stdout = out
+
+			cmd.Env = append(os.Environ(),
+				commandForMain+"="+tc.command,
+				listenAddr+"="+localhost+":0",
+				upstreamURL+"="+startApp(t),
+				stateDir+"="+t.TempDir(),
+				rulesDir+"="+t.TempDir(),
+				lookupSource+"=off")
+
+			err = cmd.Start()
+			if err != nil {
+				t.Fatalf("start: %v", err)
+			}
+
+			t.Cleanup(func() {
+				_ = cmd.Process.Kill()
+				_ = cmd.Wait()
+			})
+
+			addr, _ := out.line(t, "msg", "starting")["address"].(string)
+			ask(t, addr, "/", http.StatusOK, tc.disposition)
+
+			err = cmd.Process.Signal(syscall.SIGTERM)
+			if err != nil {
+				t.Fatalf("signal: %v", err)
+			}
+
+			err = cmd.Wait()
+			if err != nil {
+				t.Errorf("exit: %v; output:\n%s", err, out.text())
+			}
+		})
+	}
+}
+
+// ask sends servewaf at addr rproxy's question about a request for path from
+// placed, checks the answer's status and disposition, and closes it.
+func ask(t *testing.T, addr, path string, status int, disposition string) {
+	t.Helper()
+
+	req, err := http.NewRequestWithContext(t.Context(), http.MethodGet,
+		"http://"+addr+path, http.NoBody)
+	if err != nil {
+		t.Fatalf("new request: %v", err)
+	}
+
+	req.Header.Set(proxy.ClientHeader, placed)
+	req.Header.Set("X-Request-ID", rand.Text())
+
+	transport := &http.Transport{}
+	defer transport.CloseIdleConnections()
+
+	res, err := (&http.Client{Transport: transport}).Do(req)
+	if err != nil {
+		t.Fatalf("question: %v", err)
+	}
+
+	_, _ = io.Copy(io.Discard, res.Body)
+	_ = res.Body.Close()
+
+	if res.StatusCode != status ||
+		res.Header.Get(proxy.DispositionHeader) != disposition {
+		t.Errorf("answered %d with disposition %q, want %d with %q", res.StatusCode,
+			res.Header.Get(proxy.DispositionHeader), status, disposition)
+	}
+}
+
+// runServeWAF runs `smallwebwaf servewaf` with the settings in env, has use
+// send it requests at the address it listens on, stops it as SIGTERM does, and
+// checks that it stopped in order.
+func runServeWAF(t *testing.T, env map[string]string, use func(addr string)) {
+	t.Helper()
+
+	ctx, stop := context.WithCancel(t.Context())
+	out := &output{}
+	exited := make(chan int, 1)
+
+	go func() {
+		exited <- runAs(ctx, true, env, out)
+	}()
+
+	addr, _ := out.line(t, "msg", "starting")["address"].(string)
+	use(addr)
+	stop()
+
+	select {
+	case status := <-exited:
+		if status != 0 {
+			t.Fatalf("exit status %d, want 0; output:\n%s", status, out.text())
+		}
+	case <-time.After(waitLimit):
+		t.Fatal("still running after being told to stop")
+	}
+
+	out.line(t, "msg", "stopped")
+}
+
+func TestServeWAFKeepsItsBansAcrossARestartAndNeedsNoApp(t *testing.T) {
+	t.Parallel()
+
+	env := map[string]string{
+		listenAddr: localhost + ":0",
+		stateDir:   t.TempDir(),
+		rulesDir:   filepath.Join("..", "..", "share", "rules.d"),
+	}
+
+	runServeWAF(t, env, func(addr string) {
+		ask(t, addr, "/", http.StatusOK, proxy.DispositionAllow)
+		// The default rule file bans a probe for this.
+		ask(t, addr, "/.env", http.StatusForbidden, proxy.DispositionDeny)
+	})
+
+	runServeWAF(t, env, func(addr string) {
+		ask(t, addr, "/", http.StatusForbidden, proxy.DispositionDeny)
+	})
+}
+
+func TestWithoutACommandTheClientHeaderIsNoQuestion(t *testing.T) {
+	t.Parallel()
+
+	runUntilStopped(t, map[string]string{
+		listenAddr:  localhost + ":0",
+		upstreamURL: startApp(t),
+		stateDir:    t.TempDir(),
+		rulesDir:    t.TempDir(),
+	}, func(url string) {
+		req, err := http.NewRequestWithContext(t.Context(), http.MethodGet, url,
+			http.NoBody)
+		if err != nil {
+			t.Fatalf("new request: %v", err)
+		}
+
+		req.Header.Set(proxy.ClientHeader, placed)
+
+		transport := &http.Transport{}
+		defer transport.CloseIdleConnections()
+
+		res, err := (&http.Client{Transport: transport}).Do(req)
+		if err != nil {
+			t.Fatalf("request: %v", err)
+		}
+
+		body, err := io.ReadAll(res.Body)
+		_ = res.Body.Close()
+
+		if err != nil || string(body) != greeting ||
+			res.Header.Get(proxy.DispositionHeader) != "" {
+			t.Errorf("answered %q (%v) with disposition %q, want the app's greeting",
+				body, err, res.Header.Get(proxy.DispositionHeader))
+		}
+	})
+}

internal/smallwebwaf/smallwebwaf.go

@@ -1,7 +1,8 @@
 // Package smallwebwaf runs the smallwebwaf process: it reads the settings,
 // the rule files, the lookup database and the state files, serves requests
 // until it is told to stop, and then stops in an orderly way, writing the
-// state files.
+// state files. It serves them in front of an app, or, as `smallwebwaf
+// servewaf`, by answering rproxy's questions about them.
 package smallwebwaf
 
 import (
@@ -45,11 +46,15 @@ type Params struct {
 	LookupEnv func(string) (string, bool)
 	// Stdout receives the request log and the process's own messages.
 	Stdout io.Writer
+	// ServeWAF makes it `smallwebwaf servewaf`, which answers rproxy's
+	// questions, rather than the proxy in front of an app.
+	ServeWAF bool
 }
 
 // Main runs smallwebwaf until SIGTERM or SIGINT, and returns the
-// process's exit status. Run as `smallwebwaf healthcheck`, it is the
+// process's exit status. Run as `smallwebwaf servewaf`, it answers
-// container's health check instead.
+// rproxy's questions rather than pass requests to an app. Run as
+// `smallwebwaf healthcheck`, it is the container's health check instead.
 func Main(version string) int {
 	if len(os.Args) > 1 && os.Args[1] == "healthcheck" {
 		return HealthCheck(context.Background(), os.Args[2:], os.LookupEnv, os.Stderr)
@@ -63,6 +68,7 @@ func Main(version string) int {
 		Version:   version,
 		LookupEnv: os.LookupEnv,
 		Stdout:    os.Stdout,
+		ServeWAF:  len(os.Args) > 1 && os.Args[1] == "servewaf",
 	})
 }
 
@@ -117,7 +123,12 @@ func Run(ctx context.Context, params Params) int {
 		return 1
 	}
 
-	server, err := newServer(cfg, stdout, processLog, now, ruleFiles, alertQueue)
+	newProxy := proxy.New
+	if params.ServeWAF {
+		newProxy = proxy.NewServeWAF
+	}
+
+	server, err := newServer(newProxy, cfg, stdout, processLog, now, ruleFiles, alertQueue)
 	if err != nil {
 		processLog.Error("cannot use the lookup database", "error", err.Error())
 
@@ -151,10 +162,12 @@ func Run(ctx context.Context, params Params) int {
 	return serve(ctx, server, listener, files, ruleFiles, alertQueue, processLog)
 }
 
-// newServer returns the server smallwebwaf runs, with the metrics of the
+// newServer returns the server smallwebwaf runs, which newProxy makes, with
-// alerts, after reading the lookup database while SWWAF_LOOKUP_SOURCE is
+// the metrics of the alerts, after reading the lookup database while
-// file. A lookup database that cannot be read is an error.
+// SWWAF_LOOKUP_SOURCE is file. A lookup database that cannot be read is an
+// error.
 func newServer(
+	newProxy func(proxy.Params) *proxy.Server,
 	cfg *config.Config, stdout io.Writer, processLog *slog.Logger,
 	now func() time.Time, ruleFiles *rules.Files, alertQueue *alerts.Queue,
 ) (*proxy.Server, error) {
@@ -174,7 +187,7 @@ func newServer(
 		}
 	}
 
-	server := proxy.New(proxy.Params{
+	server := newProxy(proxy.Params{
 		Config:       cfg,
 		RequestLog:   stdout,
 		ProcessLog:   processLog,

internal/smallwebwaf/smallwebwaf_test.go

@@ -113,6 +113,13 @@ func (o *output) text() string {
 // returns its exit status. SWWAF_LOOKUP_SOURCE is off unless env sets it,
 // so that no test sends GeoJS its clients' addresses.
 func run(ctx context.Context, env map[string]string, out *output) int {
+	return runAs(ctx, false, env, out)
+}
+
+// runAs is run as `smallwebwaf servewaf` while serveWAF is true.
+func runAs(
+	ctx context.Context, serveWAF bool, env map[string]string, out *output,
+) int {
 	return smallwebwaf.Run(ctx, smallwebwaf.Params{
 		Version: testVersion,
 		LookupEnv: func(name string) (string, bool) {
@@ -123,7 +130,8 @@ func run(ctx context.Context, env map[string]string, out *output) int {
 
 			return value, ok
 		},
-		Stdout: out,
+		Stdout:   out,
+		ServeWAF: serveWAF,
 	})
 }
 
@@ -1240,13 +1248,13 @@ func wantStartingLine(t *testing.T, line map[string]any, appURL, dir string) {
 		"SWWAF_UPSTREAM_REQUEST_TIMEOUT":        "60s",
 		"SWWAF_UPSTREAM_RESPONSE_TIMEOUT":       "30m",
 		"SWWAF_REQUEST_MAX_BYTES":               "100M",
-		"SWWAF_RESPONSE_MAX_BYTES":              "5G",
+		"SWWAF_RESPONSE_MAX_BYTES":              "1G",
 		"SWWAF_ALLOW_NETS":                      "",
 		rateLimitExemptNets:                     "",
 		"SWWAF_DENY_NETS":                       "",
-		"SWWAF_RATE_LIMIT_PER_MINUTE":           "1000",
+		"SWWAF_RATE_LIMIT_PER_MINUTE":           "6000",
-		"SWWAF_RATE_LIMIT_PER_HOUR":             "10000",
+		"SWWAF_RATE_LIMIT_PER_HOUR":             "100000",
-		rateLimitPerDay:                         "50000",
+		rateLimitPerDay:                         "1000000",
 		"SWWAF_RATE_LIMIT_EXEMPT_PATHS":         "",
 		"SWWAF_DENIED_COUNTRIES":                "",
 		"SWWAF_EXCLUSIVELY_ALLOWED_COUNTRIES":   "",

internal/state/state.go

@@ -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'

internal/state/state_test.go

@@ -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
+		// ban, made after the admin opened the file, is lost, as the
-		// while running" in SPEC.md says.
+		// "Persistent state" section of SPEC.md says.
 		time.Sleep(time.Nanosecond)
 		synctest.Wait()
 

internal/waf/waf.go

@@ -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
+// makes to it, as "Attack detection" under "Settings" in SPEC.md describes
-// SPEC.md describes them. It reads no response.
+// 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

script/gitea-requests

@@ -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
+# that reading gitea's source found the Core Rule Set refuses, which
-# sample of gitea's ordinary use: signing in, pages of files and commits,
+# docs/gitea.md records, and a short sample of gitea's ordinary use:
-# a diff, the API, a push, clone and fetch over HTTP, and two container
+# signing in, pages of files and commits, a diff, the API, a push, clone
-# image pushes. Last, print each request smallwebwaf logged, with what it
+# and fetch over HTTP, and two container image pushes. Last, print each
-# did with it and the ids of the Core Rule Set's rules that matched it.
+# 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,