Internet exposure checks and response rate limiting

Jarl works out which views are reachable from the internet (match-clients
ending in a catch-all, not private-looking addresses: an internal view of a
global IPv6 prefix is still yours; a server without views: open allow-query
and a non-private listen address), with a per-view override (schema 9), and
checks public ones: rate limiting, open resolver, minimal-any, cache
snooping, open NOTIFY and transfers, version and host name, management
interfaces. Fixes are staged like any change, including rate limiting from
ISC's example in log-only mode with the secondaries exempt, then enforcing.
named logs what rate limiting limits (or would, in log-only mode, where its
counters don't move) as query-errors; Jarl routes those lines to its log
and counts them (rrl breakdown, ratelimited top lists, Prometheus
jarl_ratelimit_logged_total), shown on the new Exposure page.

A change that newly opens a public view up must be confirmed (accept_risk,
--accept-risk, a checkbox on the Changes page; 409 confirm_risk
otherwise). Findings can be acknowledged with a reason and stay visible as
info. GET /exposure, POST /exposure/fix|ack|unack, jarl exposure,
docs/exposure.md.

Also fixes query statistics skipping TSIG-signed queries ("IP#port/key
NAME" in named's log).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/stats/parse_test.go

@@ -1,6 +1,7 @@
 package stats
 
 import (
+	"net/netip"
 	"testing"
 	"time"
 )
@@ -42,3 +43,44 @@ func TestParseResponse(t *testing.T) {
 		}
 	}
 }
+
+func TestParseRateLimit(t *testing.T) {
+	loc := time.UTC
+	for _, tc := range []struct {
+		line  string
+		want  RateLimit
+		views bool
+	}{
+		{line: "12-Oct-2026 09:56:35.996 client @0x70a247adf000 127.0.0.2#59296 (www.rrl.test): would rate limit slip response to 127.0.0.0/24 for www.rrl.test IN A  (0ce833a4)",
+			want: RateLimit{Would: true, Action: "slip", Prefix: "127.0.0.0/24", Name: "www.rrl.test", Type: "A"}},
+		{line: "12-Oct-2026 09:56:38.303 client @0x7eee390df000 127.0.0.2#35687 (www.rrl.test): rate limit drop response to 127.0.0.0/24 for www.rrl.test IN A  (0ce833a4)",
+			want: RateLimit{Action: "drop", Prefix: "127.0.0.0/24", Name: "www.rrl.test", Type: "A"}},
+		{line: "12-Oct-2026 09:56:38.303 client @0x7eee390df000 2001:db8::7#35687 (Adbraun.lol): view external: rate limit drop response to 2001:db8::/56 for adbraun.lol IN ANY  (0ce833a4)",
+			want: RateLimit{View: "external", Action: "drop", Prefix: "2001:db8::/56", Name: "adbraun.lol", Type: "ANY"}},
+	} {
+		rl, ok := ParseRateLimit(tc.line, loc)
+		rl.Time, rl.Client = time.Time{}, netip.Addr{}
+		if !ok || rl != tc.want {
+			t.Errorf("%s:\n got %+v %v\nwant %+v", tc.line, rl, ok, tc.want)
+		}
+	}
+	if _, ok := ParseRateLimit("12-Oct-2026 09:56:35.996 rate-limit: info: would limit responses to 127.0.0.0/24 for www.rrl.test IN A  (0ce833a4)", loc); ok {
+		t.Error("the start-of-limiting line counted as a response")
+	}
+}
+
+// Signed queries have "/key NAME" after the client's port.
+func TestParseSigned(t *testing.T) {
+	loc := time.UTC
+	ev, ok := ParseResponse("12-Oct-2026 10:11:06.490 client @0x7a22f754b000 127.0.0.1#34745/key jarl-view-external (ns1.adbraun.test): view external: response: ns1.adbraun.test IN A NOERROR 1 0 2 +E(0)SK (127.0.0.1)", loc)
+	if !ok || ev.View != "external" || ev.Name != "ns1.adbraun.test" || ev.Port != "34745" {
+		t.Errorf("signed response = %+v %v", ev, ok)
+	}
+	rl, ok := ParseRateLimit("12-Oct-2026 10:11:06.599 client @0x7a22f754b000 127.0.0.1#34856/key jarl-view-external (ns1.adbraun.test): view external: would rate limit slip response to 127.0.0.0/24 for ns1.adbraun.test IN A  (e777e288)", loc)
+	if !ok || rl.View != "external" || !rl.Would || rl.Action != "slip" || rl.Prefix != "127.0.0.0/24" {
+		t.Errorf("signed rate limit = %+v %v", rl, ok)
+	}
+	if _, ok := ParseRewrite("09-Oct-2026 23:49:13.089 client @0x7bd607320000 127.0.0.1#56905/key k1 (x.ads.example): view internal: rpz QNAME NXDOMAIN rewrite x.ads.example/A/IN via x.ads.example.rules.jarl.invalid", loc); !ok {
+		t.Error("signed rewrite not parsed")
+	}
+}