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>

cmd/hc/firewall.go

@@ -298,6 +298,13 @@ func quotasCmd() *cobra.Command {
 			if err != nil {
 				return err
 			}
+			var addrs []string
+			for _, q := range qs {
+				for _, a := range q.Addresses {
+					addrs = append(addrs, a.Address)
+				}
+			}
+			names := lookupNames(addrs...)
 			return output(qs, func(w io.Writer) {
 				fmt.Fprintln(w, "RULE\tUSED\tOF\tRESETS\tNEXT RESET")
 				for _, q := range qs {
@@ -317,7 +324,7 @@ func quotasCmd() *cobra.Command {
 					}
 					fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", q.Rule, humanBytes(q.Used), of, resets, next)
 					for _, a := range q.Addresses {
-						fmt.Fprintf(w, "  %s\t%s\t\t\t\n", a.Address, humanBytes(a.Used))
+						fmt.Fprintf(w, "  %s\t%s\t\t\t\n", named(names, a.Address, a.Address), humanBytes(a.Used))
 					}
 				}
 			})
@@ -341,6 +348,11 @@ func logCmd() *cobra.Command {
 			var last time.Time
 			print := func(es []api.LogEntry) {
 				sort.Slice(es, func(i, j int) bool { return es[i].Time.Before(es[j].Time) })
+				var addrs []string
+				for _, e := range es {
+					addrs = append(addrs, e.Source, e.Dest)
+				}
+				names := lookupNames(addrs...)
 				for _, e := range es {
 					last = e.Time
 					src, dst := e.Source, e.Dest
@@ -350,6 +362,7 @@ func logCmd() *cobra.Command {
 					if e.DestPort != 0 {
 						dst = joinPort(dst, e.DestPort)
 					}
+					src, dst = named(names, e.Source, src), named(names, e.Dest, dst)
 					what := e.Protocol
 					if e.ICMPType != "" {
 						what += " " + e.ICMPType

cmd/hc/main.go

@@ -46,6 +46,7 @@ var (
 	flagCACert    string
 	flagQuiet     bool
 	flagNoConfirm bool
+	flagNoNames   bool
 	// lastClient is the client the command made (to confirm a change by
 	// itself after it).
 	lastClient *client.Client
@@ -182,6 +183,7 @@ Exit codes: 0 ok, 1 error, 3 not authenticated or not allowed, 4 not found,
 	pf.StringVar(&flagCACert, "ca-cert", "", "PEM file with a CA to trust for the server's certificate")
 	pf.BoolVarP(&flagQuiet, "quiet", "q", false, "print only errors (and IDs of new objects)")
 	pf.BoolVar(&flagNoConfirm, "no-confirm", false, "leave a change on probation instead of confirming it once this client reaches Housecarl again")
+	pf.BoolVar(&flagNoNames, "no-names", false, "show inside addresses without their names (reverse lookups)")
 	pf.Int64VarP(&flagChangeset, "changeset", "C", 0, "stage configuration changes in this changeset instead of applying them (env HOUSECARL_CHANGESET)")
 	root.AddGroup(&cobra.Group{ID: "fw", Title: "Firewall:"}, &cobra.Group{ID: "changes", Title: "Changes:"}, &cobra.Group{ID: "admin", Title: "Administration:"})
 	add := func(group string, cmds ...*cobra.Command) {

cmd/hc/objects.go

@@ -49,6 +49,46 @@ func counters() map[string]api.Counter {
 	return cs.Counters
 }
 
+// lookupNames asks for inside addresses' names, for tables: none with
+// --no-names, another output format, or when they can't be had.
+func lookupNames(addrs ...string) map[string]string {
+	out := map[string]string{}
+	if flagNoNames || flagOutput != "table" {
+		return out
+	}
+	seen := map[string]bool{}
+	var list []string
+	for _, a := range addrs {
+		if a != "" && !seen[a] {
+			seen[a] = true
+			list = append(list, a)
+		}
+	}
+	if len(list) == 0 {
+		return out
+	}
+	c, err := newClient()
+	if err != nil {
+		return out
+	}
+	var ns api.Names
+	if c.Do(ctx(), "POST", "/names", nil, api.NamesInput{Addresses: list}, &ns) != nil {
+		return out
+	}
+	for a, n := range ns.Names {
+		out[a] = strings.SplitN(n, ".", 2)[0]
+	}
+	return out
+}
+
+// named adds an address's name to text (the address, or address:port).
+func named(names map[string]string, addr, text string) string {
+	if n := names[addr]; n != "" {
+		return text + " (" + n + ")"
+	}
+	return text
+}
+
 func hits(c map[string]api.Counter, marks ...string) string {
 	var p uint64
 	found := false

cmd/hc/stats.go

@@ -283,6 +283,7 @@ func statsTopCmd() *cobra.Command {
 				for _, l := range [][]statEntry{down, up} {
 					for _, e := range l {
 						if _, ok := out[e.Key]; !ok {
+							out[e.Key] = [2]int64{}
 							order = append(order, e.Key)
 						}
 					}
@@ -297,10 +298,11 @@ func statsTopCmd() *cobra.Command {
 					v[1] = e.Count
 					out[e.Key] = v
 				}
+				names := lookupNames(order...)
 				return output(map[string]any{"up": up, "down": down}, func(w io.Writer) {
 					fmt.Fprintln(w, "DEVICE\tRECEIVED\tSENT")
 					for _, k := range order {
-						fmt.Fprintf(w, "%s\t%s\t%s\n", k, humanBytes(out[k][0]), humanBytes(out[k][1]))
+						fmt.Fprintf(w, "%s\t%s\t%s\n", named(names, k, k), humanBytes(out[k][0]), humanBytes(out[k][1]))
 					}
 				})
 			case "blocked", "tried":
@@ -309,10 +311,14 @@ func statsTopCmd() *cobra.Command {
 				if err != nil {
 					return err
 				}
+				var names map[string]string
+				if args[0] == "blocked" {
+					names = lookupNames(keys(es)...)
+				}
 				return output(es, func(w io.Writer) {
 					fmt.Fprintln(w, map[string]string{"blocked": "SOURCE", "tried": "WHAT"}[args[0]]+"\tPACKETS")
 					for _, e := range es {
-						fmt.Fprintf(w, "%s\t%d\n", e.Key, e.Count)
+						fmt.Fprintf(w, "%s\t%d\n", named(names, e.Key, e.Key), e.Count)
 					}
 				})
 			case "quota":
@@ -323,10 +329,11 @@ func statsTopCmd() *cobra.Command {
 				if err != nil {
 					return err
 				}
+				names := lookupNames(keys(es)...)
 				return output(es, func(w io.Writer) {
 					fmt.Fprintln(w, "ADDRESS\tUSED")
 					for _, e := range es {
-						fmt.Fprintf(w, "%s\t%s\n", e.Key, humanBytes(e.Count))
+						fmt.Fprintf(w, "%s\t%s\n", named(names, e.Key, e.Key), humanBytes(e.Count))
 					}
 				})
 			}
@@ -338,6 +345,15 @@ func statsTopCmd() *cobra.Command {
 	return cmd
 }
 
+// keys are a top list's keys.
+func keys(es []statEntry) []string {
+	var out []string
+	for _, e := range es {
+		out = append(out, e.Key)
+	}
+	return out
+}
+
 func statsRulesCmd() *cobra.Command {
 	var since string
 	var unused bool

cmd/hc/traffic.go

@@ -38,10 +38,16 @@ rules as it stands.
 			if err != nil {
 				return err
 			}
+			var addrs []string
+			for _, c := range cs {
+				addrs = append(addrs, c.Source, c.Destination)
+			}
+			names := lookupNames(addrs...)
 			return output(cs, func(w io.Writer) {
 				fmt.Fprintln(w, "PROTO\tFROM\tTO\tNAT\tSTATE\tEXPIRES")
 				for _, c := range cs {
-					fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\n", c.Protocol, hostPort(c.Source, c.SourcePort), hostPort(c.Destination, c.DestinationPort), natText(c), c.State, fmtSeconds(c.Timeout))
+					fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\n", c.Protocol, named(names, c.Source, hostPort(c.Source, c.SourcePort)),
+						named(names, c.Destination, hostPort(c.Destination, c.DestinationPort)), natText(c), c.State, fmtSeconds(c.Timeout))
 				}
 			})
 		},

cmd/housecarld/main.go

@@ -32,6 +32,7 @@ import (
 	"housecarl/internal/jarl"
 	"housecarl/internal/linkwatch"
 	"housecarl/internal/model"
+	"housecarl/internal/names"
 	"housecarl/internal/nflog"
 	"housecarl/internal/nft"
 	"housecarl/internal/render"
@@ -176,11 +177,15 @@ func serveCmd() *cobra.Command {
 				acme = certs.New(ctx, certs.Config{ACME: a.cfg.TLS.ACME, Version: version.Short()}, jc, a.store, a.log)
 				go acme.Run(ctx)
 			}
+			var resolver *names.Resolver
+			if a.cfg.Names.Enabled {
+				resolver = names.New(a.cfg.Names.Resolver, time.Duration(a.cfg.Names.Cache))
+			}
 			srv := server.New(server.Config{
 				Listen: a.cfg.Listen, TLSCertFile: a.cfg.TLS.CertFile, TLSKeyFile: a.cfg.TLS.KeyFile, TrustedProxies: a.cfg.Proxies(),
 				SessionLifetime: time.Duration(a.cfg.Session.Lifetime), SessionIdle: time.Duration(a.cfg.Session.IdleTimeout),
 				CookieSecure: a.cfg.Session.CookieSecure, Socket: a.cfg.Socket, ACME: acme,
-				Shadow: a.cfg.Shadow.Enabled, ShadowPosition: a.cfg.Shadow.Position,
+				Shadow: a.cfg.Shadow.Enabled, ShadowPosition: a.cfg.Shadow.Position, Names: resolver,
 			}, eng, fw, host, a.log, web.FS())
 			// Put the ruleset in force: what was on probation when
 			// housecarld stopped is rolled back first. An empty