feat: advertise DNS services to peers

Author: tinyzimmer

pkg/cmd/nodecmd/global/global.go

@@ -234,6 +234,8 @@ func (o *Options) Overlay(opts ...any) error {
 				}
 			}
 			if primaryEndpoint.IsValid() {
+				// Determine the raft and wireguard ports so we can set our
+				// advertise addresses.
 				var raftPort, wireguardPort uint16
 				for _, inOpts := range opts {
 					if vopt, ok := inOpts.(*raft.Options); ok {
@@ -321,7 +323,20 @@ func (o *Options) Overlay(opts ...any) error {
 					v.TURN.PublicIP = primaryEndpoint.String()
 				}
 			}
-
+			if v.MeshDNS.Enabled && v.MeshDNS.ListenUDP != "" && !o.DisableFeatureAdvertisement {
+				// Set the advertise DNS port
+				dnsAddr, err := netip.ParseAddrPort(v.MeshDNS.ListenUDP)
+				if err != nil {
+					return fmt.Errorf("failed to parse listen address: %w", err)
+				}
+				for _, inOpts := range opts {
+					if vopt, ok := inOpts.(*mesh.Options); ok {
+						if vopt.Mesh.DNSPort == 0 {
+							vopt.Mesh.DNSPort = int(dnsAddr.Port())
+						}
+					}
+				}
+			}
 		}
 	}
 	return nil

pkg/mesh/mesh_join.go

@@ -137,6 +137,7 @@ func (s *meshStore) joinWithConn(ctx context.Context, c *grpc.ClientConn, featur
 		PublicKey:          key.PublicKey().String(),
 		RaftPort:           int32(s.raft.ListenPort()),
 		GrpcPort:           int32(s.opts.Mesh.GRPCPort),
+		MeshdnsPort:        int32(s.opts.Mesh.DNSPort),
 		PrimaryEndpoint:    s.opts.Mesh.PrimaryEndpoint,
 		WireguardEndpoints: s.opts.WireGuard.Endpoints,
 		ZoneAwarenessId:    s.opts.Mesh.ZoneAwarenessID,

pkg/mesh/options_mesh.go

@@ -33,6 +33,7 @@ const (
 	MaxJoinRetriesEnvVar         = "MESH_MAX_JOIN_RETRIES"
 	JoinTimeoutEnvVar            = "MESH_JOIN_TIMEOUT"
 	GRPCAdvertisePortEnvVar      = "MESH_GRPC_PORT"
+	DNSAdvertisePortEnvVar       = "MESH_DNS_PORT"
 	PrimaryEndpointEnvVar        = "MESH_PRIMARY_ENDPOINT"
 	NodeRoutesEnvVar             = "MESH_ROUTES"
 	NodeDirectPeersEnvVar        = "MESH_DIRECT_PEERS"
@@ -64,6 +65,8 @@ type MeshOptions struct {
 	DirectPeers []string `json:"direct-peers,omitempty" yaml:"direct-peers,omitempty" toml:"direct-peers,omitempty"`
 	// GRPCPort is the port to advertise for gRPC.
 	GRPCPort int `json:"grpc-port,omitempty" yaml:"grpc-port,omitempty" toml:"grpc-port,omitempty"`
+	// DNSPort is the port to advertise for DNS.
+	DNSPort int `json:"dns-port,omitempty" yaml:"dns-port,omitempty" toml:"dns-port,omitempty"`
 	// NoIPv4 disables IPv4 usage.
 	NoIPv4 bool `json:"no-ipv4,omitempty" yaml:"no-ipv4,omitempty" toml:"no-ipv4,omitempty"`
 	// NoIPv6 disables IPv6 usage.
@@ -121,6 +124,8 @@ func (o *MeshOptions) BindFlags(fl *flag.FlagSet) {
 		"Join the cluster as a voter. Default behavior is to join as an observer.")
 	fl.IntVar(&o.GRPCPort, "mesh.grpc-port", util.GetEnvIntDefault(GRPCAdvertisePortEnvVar, 8443),
 		"GRPC advertise port.")
+	fl.IntVar(&o.DNSPort, "mesh.dns-port", util.GetEnvIntDefault(DNSAdvertisePortEnvVar, 0),
+		"DNS advertise port. This is set automatically when advertising is enabled and the mesh-dns server is running. Default is 0 (disabled).")
 	fl.StringVar(&o.PrimaryEndpoint, "mesh.primary-endpoint", util.GetEnvDefault(PrimaryEndpointEnvVar, ""),
 		`The primary endpoint to broadcast when joining a cluster.
 This is only necessary if the node intends on being publicly accessible.`)

pkg/meshdb/peers/peers.go

@@ -314,11 +314,8 @@ func (p *peers) ListByFeature(ctx context.Context, feature v1.Feature) ([]Node,
 	}
 	out := make([]Node, 0)
 	for _, node := range nodes {
-		for _, f := range node.Features {
-			if f == feature {
-				out = append(out, node)
-				break
-			}
+		if node.HasFeature(feature) {
+			out = append(out, node)
 		}
 	}
 	return out, nil

pkg/net/inspect/inspect.go

@@ -408,6 +408,9 @@ func (s *Server) Join(ctx context.Context, req *v1.JoinRequest) (*v1.JoinRespons
 		log.Warn("could not lookup DNS servers", slog.String("error", err.Error()))
 	} else {
 		for _, peer := range dnsServers {
+			if peer.ID == req.GetId() {
+				continue
+			}
 			switch {
 			// Prefer the IPv4 address
 			case peer.PrivateDNSAddrV4().IsValid():
@@ -437,6 +440,9 @@ func (s *Server) Join(ctx context.Context, req *v1.JoinRequest) (*v1.JoinRespons
 			return nil, status.Errorf(codes.Internal, "failed to list peers by ICE feature: %v", err)
 		}
 		for _, peer := range peers {
+			if peer.ID == req.GetId() {
+				continue
+			}
 			// We only return peers that are publicly accessible for now.
 			// This should be configurable in the future.
 			publicAddr := peer.PublicRPCAddr()