Names beside inside addresses

Reverse lookups (internal/names, POST /names) put a name beside each
inside address in connections, the log, quota usage, the dashboard's
quotas and the statistics' devices and blocked sources, in the web UI
and hc (--no-names to leave them out). Only inside addresses are looked
up: an inside zone's networks, and private ones outside the external
zones'. Names are cached (names.cache, 10m) and never stored;
names.resolver picks the DNS server.

Also: hc stats top devices listed each device twice; the dashboard's
quotas named the rule's ID twice.

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

internal/server/server_test.go

@@ -12,6 +12,7 @@ import (
 	"net/http/httptest"
 	"net/netip"
 	"os"
+	"reflect"
 	"strings"
 	"sync"
 	"testing"
@@ -21,6 +22,7 @@ import (
 	"housecarl/internal/auth"
 	"housecarl/internal/engine"
 	"housecarl/internal/model"
+	"housecarl/internal/names"
 	"housecarl/internal/nft"
 	"housecarl/internal/render"
 	"housecarl/internal/stats"
@@ -982,6 +984,41 @@ func TestConnections(t *testing.T) {
 	}
 }
 
+// TestNames: names only for inside addresses (an inside zone's network,
+// or private outside the external zones'), under the address as asked.
+func TestNames(t *testing.T) {
+	var asked []string
+	var mu sync.Mutex
+	e := newEnvWith(t, Config{Names: names.NewFunc(func(_ context.Context, a string) ([]string, error) {
+		mu.Lock()
+		asked = append(asked, a)
+		mu.Unlock()
+		return []string{"host-" + strings.ReplaceAll(a, ".", "-") + ".example.net."}, nil
+	}, time.Hour)})
+	e.call(e.token, "POST", "/zones", model.Zone{Name: "wan", Interfaces: []string{"wan"}, External: true}, nil)
+	e.call(e.token, "POST", "/zones", model.Zone{Name: "lan", Interfaces: []string{"eth1"}}, nil)
+	var out api.Names
+	e.call(e.token, "POST", "/names", api.NamesInput{Addresses: []string{"10.0.10.5", "::ffff:10.0.10.5", "192.168.7.7", "217.155.8.194", "8.8.8.8", "fe80::1", "nonsense"}}, &out)
+	want := map[string]string{"10.0.10.5": "host-10-0-10-5.example.net", "::ffff:10.0.10.5": "host-10-0-10-5.example.net", "192.168.7.7": "host-192-168-7-7.example.net"}
+	if !out.Enabled || !reflect.DeepEqual(out.Names, want) {
+		t.Errorf("names: %+v", out)
+	}
+	if len(asked) != 2 {
+		t.Errorf("looked up %v, want the two inside addresses once each", asked)
+	}
+	var tok api.Token
+	e.call(e.token, "POST", "/me/tokens", api.TokenInput{Name: "monitor", Role: "log"}, &tok)
+	var one, none api.Names
+	if code := e.call(tok.Secret, "POST", "/names", api.NamesInput{Addresses: []string{"10.0.10.5"}}, &one); code != 200 || len(one.Names) != 1 {
+		t.Errorf("with log:read: %d %+v", code, one)
+	}
+	off := newEnv(t)
+	off.call(off.token, "POST", "/names", api.NamesInput{Addresses: []string{"10.0.10.5"}}, &none)
+	if none.Enabled || len(none.Names) != 0 {
+		t.Errorf("names off: %+v", none)
+	}
+}
+
 // TestTrace: a trace runs with the filter's table, collects packets named
 // after Housecarl's objects, and stops when asked; one at a time.
 func TestTrace(t *testing.T) {