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/validate/validate.go

@@ -11,6 +11,7 @@ package validate
 
 import (
 	"fmt"
+	"net/netip"
 	"sort"
 	"strings"
 
@@ -37,6 +38,9 @@ type Problem struct {
 	Zone       string   `json:"zone,omitempty"`
 	View       string   `json:"view,omitempty"`
 	Name       string   `json:"name,omitempty"`
+	// Acknowledged is set when an exposure finding was accepted on
+	// purpose (it is then info, not a warning).
+	Acknowledged *model.Acknowledgement `json:"acknowledged,omitempty"`
 }
 
 // Key identifies a problem independently of object IDs, so problems can be
@@ -67,6 +71,10 @@ type Options struct {
 	// ExternalKeysUnknown is set when an included file could not be read,
 	// so references to unknown keys are not reported.
 	ExternalKeysUnknown bool
+	// LocalAddrs are this host's addresses: a server without views is
+	// public when named listens on one that isn't private
+	// (docs/exposure.md).
+	LocalAddrs []netip.Addr
 }
 
 // Result holds the problems found.
@@ -140,8 +148,10 @@ func State(s *model.State, opts Options) []Problem {
 	c.checkZones()
 	c.checkOptions()
 	c.checkSecurity()
+	c.checkExposure()
 	c.checkDNSSEC()
 	c.checkBlocking()
+	c.applyAcks()
 	sortProblems(c.problems)
 	return c.problems
 }