graph/db+chanbackup: dns add encoding/decoding for persistence

graph/db/addr.go

@@ -31,8 +31,36 @@ 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
+
+	// dnsAddr denotes a DNS address type.
+	dnsAddr addressType = 5
 )
 
+// encodeDNSAddr encodes a DNS address.
+func encodeDNSAddr(w io.Writer, addr *lnwire.DNSAddress) error {
+	if _, err := w.Write([]byte{byte(dnsAddr)}); err != nil {
+		return err
+	}
+
+	// Write the length of the hostname.
+	hostLen := len(addr.Hostname)
+	if _, err := w.Write([]byte{byte(hostLen)}); err != nil {
+		return err
+	}
+
+	if _, err := w.Write([]byte(addr.Hostname)); err != nil {
+		return err
+	}
+
+	var port [2]byte
+	byteOrder.PutUint16(port[:], addr.Port)
+	if _, err := w.Write(port[:]); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // encodeTCPAddr serializes a TCP address into its compact raw bytes
 // representation.
 func encodeTCPAddr(w io.Writer, addr *net.TCPAddr) error {
@@ -230,6 +258,30 @@ func DeserializeAddr(r io.Reader) (net.Addr, error) {
 			Port:         port,
 		}
 
+	case dnsAddr:
+		// Read the length of the hostname.
+		var hostLen [1]byte
+		if _, err := r.Read(hostLen[:]); err != nil {
+			return nil, err
+		}
+
+		// Read the hostname.
+		hostname := make([]byte, hostLen[0])
+		if _, err := r.Read(hostname); err != nil {
+			return nil, err
+		}
+
+		// Read the port.
+		var port [2]byte
+		if _, err := r.Read(port[:]); err != nil {
+			return nil, err
+		}
+
+		address = &lnwire.DNSAddress{
+			Hostname: string(hostname),
+			Port:     binary.BigEndian.Uint16(port[:]),
+		}
+
 	case opaqueAddrs:
 		// Read the length of the payload.
 		var l [2]byte
@@ -264,6 +316,8 @@ func SerializeAddr(w io.Writer, address net.Addr) error {
 		return encodeOnionAddr(w, addr)
 	case *lnwire.OpaqueAddrs:
 		return encodeOpaqueAddrs(w, addr)
+	case *lnwire.DNSAddress:
+		return encodeDNSAddr(w, addr)
 	default:
 		return ErrUnknownAddressType
 	}