multi: add dns_hostname_address field

Author: mohamedawnallah

config.go

@@ -330,26 +330,28 @@ 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"`
 
@@ -1579,6 +1581,7 @@ 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
@@ -1602,6 +1605,23 @@ 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.

docs/release-notes/release-notes-0.20.0.md

@@ -63,6 +63,10 @@
 # Technical and Architectural Updates
 ## BOLT Spec Updates
 
+* [Support DNS hostname address in
+  Node Announcement message](https://github.com/lightningnetwork/lnd/pull/9455).
+  See Bolt 07.
+
 ## Testing
 
 ## Database

graph/db/addr.go

@@ -31,6 +31,9 @@ const (
 	// opaqueAddrs denotes an address (or a set of addresses) that LND was
 	// not able to parse since LND is not yet aware of the address type.
 	opaqueAddrs addressType = 4
+
+	// dnsHostnameAddr denotes a DNS hostname address.
+	dnsHostnameAddr addressType = 5
 )
 
 // encodeTCPAddr serializes a TCP address into its compact raw bytes
@@ -147,6 +150,50 @@ func encodeOpaqueAddrs(w io.Writer, addr *lnwire.OpaqueAddrs) error {
 	return err
 }
 
+// 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 complies with bolt 7
+// requirements. Returns an error if any part of the serialization fails.
+func encodeDNSHostnameAddr(w io.Writer, addr *lnwire.DNSHostnameAddress) error {
+	// Ensure the hostname is not empty.
+	if len(addr.Hostname) == 0 {
+		return errors.New("hostname cannot be empty")
+	}
+
+	// Ensure the hostname length complies with Bolt 7 requirements.
+	// The maximum allowed length for a hostname is 255 characters.
+	if len(addr.Hostname) > 255 {
+		return fmt.Errorf("hostname length is %d, exceeds maximum "+
+			"length of 255 characters", len(addr.Hostname))
+	}
+
+	// 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.
@@ -247,6 +294,33 @@ func DeserializeAddr(r io.Reader) (net.Addr, error) {
 			Payload: payload,
 		}
 
+	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
+		n, err := r.Read(port[:])
+		if err != nil {
+			return nil, err
+		}
+		if n != 2 {
+			return nil, fmt.Errorf("expected to read 2 bytes for "+
+				"port, but got %d bytes", n)
+		}
+
+		address = &lnwire.DNSHostnameAddress{
+			Hostname: string(hostname),
+			Port:     int(binary.BigEndian.Uint16(port[:])),
+		}
+
 	default:
 		return nil, ErrUnknownAddressType
 	}
@@ -262,6 +336,8 @@ 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)
 	case *lnwire.OpaqueAddrs:
 		return encodeOpaqueAddrs(w, addr)
 	default: