servewaf always answers rproxy well within its time limit (closes #182)

A question waits on GeoJS at most 800ms, the new default of
SWWAF_LOOKUP_TIMEOUT. It does not wait at all when the checks will refuse
it whatever GeoJS answers. Just before the Core Rule Set, servewaf refuses
more than 50 cookies or 100 header fields with 431.

Shared default changed: SWWAF_LOOKUP_TIMEOUT also applies to smallwebwaf
with no command.
Judgement call: SWWAF_REPUTATION_TIMEOUT stays 2s, since no request waits
on the DNS blocklists or AbuseIPDB.

Model: opus-5-5

internal/proxy/lookup.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"net/http"
 	"net/netip"
+	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/lookup"
 )
@@ -23,17 +24,23 @@ const (
 // SWWAF_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.
-// ctx is the request's own context.
-func (rq *request) lookUp(ctx context.Context) {
+// country list or a biased threshold, a new client's request waits for it,
+// unless servewaf will refuse the request whatever the answer says. 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
 	}
 
-	if rq.h.config.LookupSource == "file" {
-		rq.lookupAnswer = rq.h.lookupFile.LookUp(rq.h.clientGroup(rq.client))
-	} else {
-		rq.lookupAnswer = rq.h.geojs.LookUp(ctx, rq.h.clientGroup(rq.client))
+	client := rq.h.clientGroup(rq.client)
+
+	switch {
+	case rq.h.config.LookupSource == "file":
+		rq.lookupAnswer = rq.h.lookupFile.LookUp(client)
+	case rq.h.answersQuestions() && rq.refusedWhateverTheAnswer(now):
+		rq.lookupAnswer = rq.h.geojs.LookUpWithoutWaiting(ctx, client)
+	default:
+		rq.lookupAnswer = rq.h.geojs.LookUp(ctx, client)
 	}
 
 	rq.lookedUp = true