fix parsing of transport headers with empty source (https://github.com/aler9/rtsp-simple-server/issues/986)

pkg/headers/transport.go

@@ -144,25 +144,29 @@ func (h *Transport) Read(v base.HeaderValue) error {
 			h.Delivery = &v
 
 		case "source":
-			ip := net.ParseIP(v)
-			if ip == nil {
-				addrs, err := net.LookupHost(v)
-				if err != nil {
-					return fmt.Errorf("invalid source (%v)", v)
-				}
-				ip = net.ParseIP(addrs[0])
+			if v != "" {
+				ip := net.ParseIP(v)
 				if ip == nil {
-					return fmt.Errorf("invalid source (%v)", v)
+					addrs, err := net.LookupHost(v)
+					if err != nil {
+						return fmt.Errorf("invalid source (%v)", v)
+					}
+					ip = net.ParseIP(addrs[0])
+					if ip == nil {
+						return fmt.Errorf("invalid source (%v)", v)
+					}
 				}
+				h.Source = &ip
 			}
-			h.Source = &ip
 
 		case "destination":
-			ip := net.ParseIP(v)
-			if ip == nil {
-				return fmt.Errorf("invalid destination (%v)", v)
+			if v != "" {
+				ip := net.ParseIP(v)
+				if ip == nil {
+					return fmt.Errorf("invalid destination (%v)", v)
+				}
+				h.Destination = &ip
 			}
-			h.Destination = &ip
 
 		case "interleaved":
 			ports, err := parsePorts(v)

pkg/headers/transport_test.go

@@ -198,6 +198,24 @@ var casesTransport = []struct {
 			}(),
 		},
 	},
+	{
+		"empty source",
+		base.HeaderValue{`RTP/AVP/UDP;unicast;source=;client_port=32560-32561;server_port=3046-3047;ssrc=45dcb578`},
+		base.HeaderValue{`RTP/AVP;unicast;client_port=32560-32561;server_port=3046-3047;ssrc=45DCB578`},
+		Transport{
+			Protocol: TransportProtocolUDP,
+			Delivery: func() *TransportDelivery {
+				v := TransportDeliveryUnicast
+				return &v
+			}(),
+			SSRC: func() *uint32 {
+				v := uint32(0x45dcb578)
+				return &v
+			}(),
+			ClientPorts: &[2]int{32560, 32561},
+			ServerPorts: &[2]int{3046, 3047},
+		},
+	},
 }
 
 func TestTransportRead(t *testing.T) {