discovery+lnwire: add support for DNS host name in NodeAnnouncement msg

cmd/commands/peersrpc_active.go

@@ -69,6 +69,10 @@ var updateNodeAnnouncementCommand = cli.Command{
 			Name:  "color",
 			Usage: "the new color for this node, e.g. #c42a81",
 		},
+		cli.StringFlag{
+			Name:  "dns_hostname_address",
+			Usage: "the new dns hostname address for this node",
+		},
 		cli.Int64SliceFlag{
 			Name: "feature_bit_add",
 			Usage: "a feature bit index that needs to be enabled. " +
@@ -124,6 +128,11 @@ func updateNodeAnnouncement(ctx *cli.Context) error {
 		req.Color = ctx.String("color")
 	}
 
+	if ctx.IsSet("dns_hostname_address") {
+		change = true
+		req.DnsHostnameAddress = ctx.String("dns_hostname_address")
+	}
+
 	if ctx.IsSet("feature_bit_add") {
 		change = true
 		for _, feature := range ctx.Int64Slice("feature_bit_add") {

config.go

@@ -325,26 +325,28 @@ type Config struct {
 	// loadConfig function. We need to expose the 'raw' strings so the
 	// command line library can access them.
 	// Only the parsed net.Addrs should be used!
-	RawRPCListeners   []string `long:"rpclisten" description:"Add an interface/port/socket to listen for RPC connections"`
-	RawRESTListeners  []string `long:"restlisten" description:"Add an interface/port/socket to listen for REST connections"`
-	RawListeners      []string `long:"listen" description:"Add an interface/port to listen for peer connections"`
-	RawExternalIPs    []string `long:"externalip" description:"Add an ip:port to the list of local addresses we claim to listen on to peers. If a port is not specified, the default (9735) will be used regardless of other parameters"`
-	ExternalHosts     []string `long:"externalhosts" description:"Add a hostname:port that should be periodically resolved to announce IPs for. If a port is not specified, the default (9735) will be used."`
-	RPCListeners      []net.Addr
-	RESTListeners     []net.Addr
-	RestCORS          []string `long:"restcors" description:"Add an ip:port/hostname to allow cross origin access from. To allow all origins, set as \"*\"."`
-	Listeners         []net.Addr
-	ExternalIPs       []net.Addr
-	DisableListen     bool          `long:"nolisten" description:"Disable listening for incoming peer connections"`
-	DisableRest       bool          `long:"norest" description:"Disable REST API"`
-	DisableRestTLS    bool          `long:"no-rest-tls" description:"Disable TLS for REST connections"`
-	WSPingInterval    time.Duration `long:"ws-ping-interval" description:"The ping interval for REST based WebSocket connections, set to 0 to disable sending ping messages from the server side"`
-	WSPongWait        time.Duration `long:"ws-pong-wait" description:"The time we wait for a pong response message on REST based WebSocket connections before the connection is closed as inactive"`
-	NAT               bool          `long:"nat" description:"Toggle NAT traversal support (using either UPnP or NAT-PMP) to automatically advertise your external IP address to the network -- NOTE this does not support devices behind multiple NATs"`
-	AddPeers          []string      `long:"addpeer" description:"Specify peers to connect to first"`
-	MinBackoff        time.Duration `long:"minbackoff" description:"Shortest backoff when reconnecting to persistent peers. Valid time units are {s, m, h}."`
-	MaxBackoff        time.Duration `long:"maxbackoff" description:"Longest backoff when reconnecting to persistent peers. Valid time units are {s, m, h}."`
-	ConnectionTimeout time.Duration `long:"connectiontimeout" description:"The timeout value for network connections. Valid time units are {ms, s, m, h}."`
+	RawRPCListeners               []string `long:"rpclisten" description:"Add an interface/port/socket to listen for RPC connections"`
+	RawRESTListeners              []string `long:"restlisten" description:"Add an interface/port/socket to listen for REST connections"`
+	RawListeners                  []string `long:"listen" description:"Add an interface/port to listen for peer connections"`
+	RawExternalIPs                []string `long:"externalip" description:"Add an ip:port to the list of local addresses we claim to listen on to peers. If a port is not specified, the default (9735) will be used regardless of other parameters"`
+	RawExternalDNSHostnameAddress string   `long:"external-dns-hostname" description:"Specify a DNS hostname for the node's external address. If no port is provided, the default (9735) is used."`
+	ExternalHosts                 []string `long:"externalhosts" description:"Add a hostname:port that should be periodically resolved to announce IPs for. If a port is not specified, the default (9735) will be used."`
+	RPCListeners                  []net.Addr
+	RESTListeners                 []net.Addr
+	RestCORS                      []string `long:"restcors" description:"Add an ip:port/hostname to allow cross origin access from. To allow all origins, set as \"*\"."`
+	Listeners                     []net.Addr
+	ExternalIPs                   []net.Addr
+	ExternalDNSHostnameAddress    *lnwire.DNSHostnameAddress
+	DisableListen                 bool          `long:"nolisten" description:"Disable listening for incoming peer connections"`
+	DisableRest                   bool          `long:"norest" description:"Disable REST API"`
+	DisableRestTLS                bool          `long:"no-rest-tls" description:"Disable TLS for REST connections"`
+	WSPingInterval                time.Duration `long:"ws-ping-interval" description:"The ping interval for REST based WebSocket connections, set to 0 to disable sending ping messages from the server side"`
+	WSPongWait                    time.Duration `long:"ws-pong-wait" description:"The time we wait for a pong response message on REST based WebSocket connections before the connection is closed as inactive"`
+	NAT                           bool          `long:"nat" description:"Toggle NAT traversal support (using either UPnP or NAT-PMP) to automatically advertise your external IP address to the network -- NOTE this does not support devices behind multiple NATs"`
+	AddPeers                      []string      `long:"addpeer" description:"Specify peers to connect to first"`
+	MinBackoff                    time.Duration `long:"minbackoff" description:"Shortest backoff when reconnecting to persistent peers. Valid time units are {s, m, h}."`
+	MaxBackoff                    time.Duration `long:"maxbackoff" description:"Longest backoff when reconnecting to persistent peers. Valid time units are {s, m, h}."`
+	ConnectionTimeout             time.Duration `long:"connectiontimeout" description:"The timeout value for network connections. Valid time units are {ms, s, m, h}."`
 
 	DebugLevel string `short:"d" long:"debuglevel" description:"Logging level for all subsystems {trace, debug, info, warn, error, critical} -- You may also specify <global-level>,<subsystem>=<level>,<subsystem2>=<level>,... to set the log level for individual subsystems -- Use show to list available subsystems"`
 
@@ -1555,6 +1557,7 @@ func ValidateConfig(cfg Config, interceptor signal.Interceptor, fileParser,
 		ltndLog.Infof("Listening on the p2p interface is disabled!")
 		cfg.Listeners = nil
 		cfg.ExternalIPs = nil
+		cfg.ExternalDNSHostnameAddress = nil
 	} else {
 
 		// Add default port to all listener addresses if needed and remove
@@ -1578,6 +1581,23 @@ func ValidateConfig(cfg Config, interceptor signal.Interceptor, fileParser,
 			return nil, err
 		}
 
+		// Add default port to external dnsh hostname address if needed.
+		if cfg.RawExternalDNSHostnameAddress != "" {
+			addr, err := parseAddr(
+				cfg.RawExternalDNSHostnameAddress, cfg.net,
+			)
+			if err != nil {
+				return nil, err
+			}
+			dnsAddr, ok := addr.(*lnwire.DNSHostnameAddress)
+			if !ok {
+				return nil, fmt.Errorf("failed to cast "+
+					"address to lnwire.DNSHostnameAddr: "+
+					"got %T", addr)
+			}
+			cfg.ExternalDNSHostnameAddress = dnsAddr
+		}
+
 		// For the p2p port it makes no sense to listen to an Unix socket.
 		// Also, we would need to refactor the brontide listener to support
 		// that.

discovery/gossiper.go

@@ -1988,6 +1988,7 @@ func (d *AuthenticatedGossiper) addNode(msg *lnwire.NodeAnnouncement,
 		HaveNodeAnnouncement: true,
 		LastUpdate:           timestamp,
 		Addresses:            msg.Addresses,
+		DNSHostnameAddress:   msg.DNSHostnameAddress,
 		PubKeyBytes:          msg.NodeID,
 		Alias:                msg.Alias.String(),
 		AuthSigBytes:         msg.Signature.ToSignatureBytes(),

graph/db/addr.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"net"
 
+	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/tor"
 )
 
@@ -26,6 +27,9 @@ const (
 
 	// v3OnionAddr denotes a version 3 Tor (prop224) onion service address.
 	v3OnionAddr addressType = 3
+
+	// dnsHostnameAddr denotes a DNS hostname address.
+	dnsHostnameAddr addressType = 4
 )
 
 // encodeTCPAddr serializes a TCP address into its compact raw bytes
@@ -121,6 +125,47 @@ func encodeOnionAddr(w io.Writer, addr *tor.OnionAddr) error {
 	return nil
 }
 
+// encodeDNSHostnameAddr serializes a DNS hostname address into its compact raw
+// bytes representation. It writes the address type, hostname length, hostname,
+// and port (in big-endian order) to the writer. The function validates that the
+// hostname is non-empty and does not exceed 255 characters. Returns an error if
+// any part of the serialization fails.
+func encodeDNSHostnameAddr(w io.Writer, addr *lnwire.DNSHostnameAddress) error {
+	// Validate the hostname.
+	if len(addr.Hostname) == 0 {
+		return errors.New("hostname cannot be empty")
+	}
+	if len(addr.Hostname) > 255 {
+		return errors.New("hostname exceeds maximum length of 255 " +
+			"characters")
+	}
+
+	// Write the address type.
+	if _, err := w.Write([]byte{byte(dnsHostnameAddr)}); err != nil {
+		return err
+	}
+
+	// Write the length of the hostname.
+	hostnameLen := byte(len(addr.Hostname))
+	if _, err := w.Write([]byte{hostnameLen}); err != nil {
+		return err
+	}
+
+	// Write the hostname bytes.
+	if _, err := w.Write([]byte(addr.Hostname)); err != nil {
+		return err
+	}
+
+	// Write the port in big-endian order.
+	var port [2]byte
+	binary.BigEndian.PutUint16(port[:], uint16(addr.Port))
+	if _, err := w.Write(port[:]); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // DeserializeAddr reads the serialized raw representation of an address and
 // deserializes it into the actual address. This allows us to avoid address
 // resolution within the channeldb package.
@@ -200,6 +245,29 @@ func DeserializeAddr(r io.Reader) (net.Addr, error) {
 			OnionService: onionService,
 			Port:         port,
 		}
+
+	case dnsHostnameAddr:
+		var hostnameLen byte
+		err := binary.Read(r, binary.BigEndian, &hostnameLen)
+		if err != nil {
+			return nil, err
+		}
+
+		hostname := make([]byte, hostnameLen)
+		if _, err := r.Read(hostname); err != nil {
+			return nil, err
+		}
+
+		var port [2]byte
+		if _, err := r.Read(port[:]); err != nil {
+			return nil, err
+		}
+
+		address = &lnwire.DNSHostnameAddress{
+			Hostname: string(hostname),
+			Port:     int(binary.BigEndian.Uint16(port[:])),
+		}
+
 	default:
 		return nil, ErrUnknownAddressType
 	}
@@ -215,6 +283,8 @@ func SerializeAddr(w io.Writer, address net.Addr) error {
 		return encodeTCPAddr(w, addr)
 	case *tor.OnionAddr:
 		return encodeOnionAddr(w, addr)
+	case *lnwire.DNSHostnameAddress:
+		return encodeDNSHostnameAddr(w, addr)
 	default:
 		return ErrUnknownAddressType
 	}

graph/db/graph.go

@@ -3972,13 +3972,20 @@ func putLightningNode(nodeBucket kvdb.RwBucket, aliasBucket kvdb.RwBucket, // no
 		return err
 	}
 
-	numAddresses := uint16(len(node.Addresses))
+	var allAddresses []net.Addr
+	var numAddresses uint16
+	if node.DNSHostnameAddress != nil {
+		allAddresses = append(allAddresses, node.DNSHostnameAddress)
+		numAddresses += 1
+	}
+	allAddresses = append(allAddresses, node.Addresses...)
+	numAddresses += uint16(len(node.Addresses))
 	byteOrder.PutUint16(scratch[:2], numAddresses)
 	if _, err := b.Write(scratch[:2]); err != nil {
 		return err
 	}
 
-	for _, address := range node.Addresses {
+	for _, address := range allAddresses {
 		if err := SerializeAddr(&b, address); err != nil {
 			return err
 		}
@@ -4171,14 +4178,20 @@ func deserializeLightningNode(r io.Reader) (models.LightningNode, error) {
 	numAddresses := int(byteOrder.Uint16(scratch[:2]))
 
 	var addresses []net.Addr
+	var dnsHostnameAddress *lnwire.DNSHostnameAddress
 	for i := 0; i < numAddresses; i++ {
 		address, err := DeserializeAddr(r)
 		if err != nil {
 			return models.LightningNode{}, err
 		}
-		addresses = append(addresses, address)
+		if dnsAddr, ok := address.(*lnwire.DNSHostnameAddress); ok {
+			dnsHostnameAddress = dnsAddr
+		} else {
+			addresses = append(addresses, address)
+		}
 	}
 	node.Addresses = addresses
+	node.DNSHostnameAddress = dnsHostnameAddress
 
 	node.AuthSigBytes, err = wire.ReadVarBytes(r, 0, 80, "sig")
 	if err != nil {

graph/db/models/node.go

@@ -32,6 +32,9 @@ type LightningNode struct {
 	// Address is the TCP address this node is reachable over.
 	Addresses []net.Addr
 
+	// DNSHostnameAddress is the DNS hostname address for this node.
+	DNSHostnameAddress *lnwire.DNSHostnameAddress
+
 	// Color is the selected color for the node.
 	Color color.RGBA
 
@@ -109,13 +112,14 @@ func (l *LightningNode) NodeAnnouncement(signed bool) (*lnwire.NodeAnnouncement,
 	}
 
 	nodeAnn := &lnwire.NodeAnnouncement{
-		Features:        l.Features.RawFeatureVector,
-		NodeID:          l.PubKeyBytes,
-		RGBColor:        l.Color,
-		Alias:           alias,
-		Addresses:       l.Addresses,
-		Timestamp:       uint32(l.LastUpdate.Unix()),
-		ExtraOpaqueData: l.ExtraOpaqueData,
+		Features:           l.Features.RawFeatureVector,
+		NodeID:             l.PubKeyBytes,
+		RGBColor:           l.Color,
+		Alias:              alias,
+		Addresses:          l.Addresses,
+		DNSHostnameAddress: l.DNSHostnameAddress,
+		Timestamp:          uint32(l.LastUpdate.Unix()),
+		ExtraOpaqueData:    l.ExtraOpaqueData,
 	}
 
 	if !signed {

lnrpc/devrpc/dev.swagger.json

@@ -235,6 +235,10 @@
             "format": "byte"
           },
           "description": "Custom node announcement tlv records."
+        },
+        "dns_hostname_address": {
+          "$ref": "#/definitions/lnrpcNodeAddress",
+          "description": "The DNS hostname address of the node, if available."
         }
       },
       "description": "An individual vertex/node within the channel graph. A node is\nconnected to other nodes by one or more channel edges emanating from it. As the\ngraph is directed, a node will also have an incoming edge attached to it for\neach outgoing edge."