Files
smallwebwaf/internal/discriminator/lookup.go
T
clawbot 1f1e97cb4e
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Request tags, with refusing and limits per tag (closes #175)
Each request gets sorted tags from the lookup, new address lists, the
reputation sources and the rule matches, logged as `tags`. New settings:
`SWW_TAG_LISTS`, `SWW_TAG_DENY`, `SWW_TAG_LIMIT_PERCENT`. They replace
`SWW_ASN_LIMIT_PERCENT`, `SWW_COUNTRY_LIMIT_PERCENT` and
`SWW_DENIED_COUNTRIES`. New heuristics `tag_lists` and `tag_deny`; the
latter runs before the rate limits and again after the Core Rule Set.

Model: opus-5-5
2026-11-09 00:39:59 +00:00

109 lines
3.3 KiB
Go

package discriminator
import (
"context"
"net/http"
"net/netip"
"strings"
"time"
"sneak.berlin/go/smallwebwaf/internal/lookup"
)
// The headers in which an answer of allow gives rproxy the client's AS number
// and country, for the app, while SWW_ADD_LOOKUP_HEADERS is set. Go writes
// every header name in this form, as it sends it and as it receives it, so
// X-Client-ASN arrives as X-Client-Asn; header names are not case-sensitive.
const (
asnHeader = "X-Client-Asn"
countryHeader = "X-Client-Country"
)
// lookUp looks up the client's AS number and country, in the lookup
// database or through GeoJS, and notes them for the log line and as the
// request's asn= and country= tags, unless
// SWW_LOOKUP_SOURCE is off or the client is on a private, loopback or
// link-local address, which no lookup can place. The lookup database
// answers at once. With GeoJS, while a setting needs the answer, such as a
// country list or a biased threshold, a new client's request waits for it,
// unless refusedWhateverTheAnswer reports true. ctx is the request's own
// context.
func (rq *request) lookUp(ctx context.Context, now time.Time) {
if rq.h.config.LookupSource == "off" || !canBePlaced(rq.client) {
return
}
client := rq.h.clientGroup(rq.client)
switch {
case rq.h.config.LookupSource == "file":
rq.lookupAnswer = rq.h.lookupFile.LookUp(client)
case rq.refusedWhateverTheAnswer(now):
rq.lookupAnswer = rq.h.geojs.LookUpWithoutWaiting(ctx, client)
rq.skippedLookupWait = rq.lookupAnswer.Answered.IsZero()
default:
rq.lookupAnswer = rq.h.geojs.LookUp(ctx, client)
}
rq.lookedUp = true
rq.line.ASN = rq.lookupAnswer.ASN
rq.line.ASName = rq.lookupAnswer.ASName
rq.line.Country = rq.lookupAnswer.Country
if tag := asnTag(rq.line.ASN); tag != "" {
rq.addTag(tag)
}
if tag := countryTag(rq.line.Country); tag != "" {
rq.addTag(tag)
}
}
// asnTag returns the tag of asn, an AS number as the lookup gives it, such as
// asn=64496 for AS64496, or "" for no AS number.
func asnTag(asn string) string {
if asn == "" {
return ""
}
return "asn=" + strings.TrimPrefix(asn, "AS")
}
// countryTag returns the tag of country, a code as the lookup gives it, such
// as country=de for DE, or "" for no country.
func countryTag(country string) string {
if country == "" {
return ""
}
return "country=" + strings.ToLower(country)
}
// addLookup adds answer, an answer about a client from the lookup
// database or GeoJS, to the client's history, and to the notes of the bans
// on its netblock that have no AS number, AS name or country yet.
func (h *handler) addLookup(answer lookup.Answer) {
h.limiter.AddLookup(answer.Client, answer.Answered,
answer.ASN, answer.ASName, answer.Country)
h.ledger.AddLookup(h.netblock(answer.Client.Addr()),
answer.ASN, answer.ASName, answer.Country)
}
// setLookupHeaders sets the headers that give the client's AS number and
// country, leaving out one that is unknown.
func setLookupHeaders(header http.Header, asn, country string) {
if asn != "" {
header.Set(asnHeader, asn)
}
if country != "" {
header.Set(countryHeader, country)
}
}
// canBePlaced reports whether a lookup can place addr: private, loopback
// and link-local addresses have no AS number or country.
func canBePlaced(addr netip.Addr) bool {
return !addr.IsPrivate() && !addr.IsLoopback() && !addr.IsLinkLocalUnicast()
}