protocol/rtcp: wrote test for SourceDescription.Bytes() and made modifiations to make it pass.

protocol/rtcp/rtcp.go

@@ -8,7 +8,13 @@ import (
 
 // RTCP packet types.
 const (
-	typeReceiverReport = 201
+	typeReceiverReport    = 201
+	typeSourceDescription = 202
+)
+
+// SDES Item types.
+const (
+	typeCName = 1
 )
 
 const (
@@ -18,6 +24,7 @@ const (
 type ReceiverReport struct {
 	Header
 
+	SenderSSRC uint32
 	Blocks     []ReportBlock
 	Extensions [][4]byte
 }
@@ -28,6 +35,7 @@ func (r *ReceiverReport) Bytes() []byte {
 
 	l = 1 + reportBlockSize*len(r.Blocks) + len(r.Extensions)
 	r.writeHeader(buf, l)
+	binary.BigEndian.PutUint32(buf[4:], r.SenderSSRC)
 
 	idx := 8
 	for _, b := range r.Blocks {
@@ -62,10 +70,14 @@ type SourceDescription struct {
 
 func (d *SourceDescription) Bytes() []byte {
 	bodyLen := d.bodyLen()
-	l := 8 + bodyLen
+	rem := bodyLen % 4
+	if rem != 0 {
+		bodyLen += 4 - rem
+	}
+	l := 4 + bodyLen
 	buf := make([]byte, l)
 	d.writeHeader(buf, bodyLen/4)
-	idx := 8
+	idx := 4
 	for _, c := range d.Chunks {
 		binary.BigEndian.PutUint32(buf[idx:], c.SSRC)
 		idx += 4
@@ -90,11 +102,10 @@ func (d *SourceDescription) bodyLen() int {
 }
 
 type Header struct {
-	Version     uint8  // RTCP version.
-	Padding     bool   // Padding indicator.
-	ReportCount uint8  // Number of reports contained.
-	Type        uint8  // Type of RTCP packet.
-	SenderSSRC  uint32 // Source identifier.
+	Version     uint8 // RTCP version.
+	Padding     bool  // Padding indicator.
+	ReportCount uint8 // Number of reports contained.
+	Type        uint8 // Type of RTCP packet.
 }
 
 type ReportBlock struct {
@@ -129,7 +140,6 @@ func (h Header) writeHeader(buf []byte, l int) {
 	buf[0] = h.Version<<6 | asByte(h.Padding)<<5 | 0x1f&h.ReportCount
 	buf[1] = h.Type
 	binary.BigEndian.PutUint16(buf[2:], uint16(l))
-	binary.BigEndian.PutUint32(buf[4:], h.SenderSSRC)
 }
 
 func asByte(b bool) byte {

protocol/rtcp/rtcp_test.go

@@ -24,8 +24,8 @@ func TestReceiverReportBytes(t *testing.T) {
 			Padding:     false,
 			ReportCount: 1,
 			Type:        typeReceiverReport,
-			SenderSSRC:  3605043418,
 		},
+		SenderSSRC: 3605043418,
 		Blocks: []ReportBlock{
 			ReportBlock{
 				SSRC:            1873625286,
@@ -49,5 +49,37 @@ func TestReceiverReportBytes(t *testing.T) {
 }
 
 func TestSourceDescriptionBytes(t *testing.T) {
+	expect := []byte{
+		0x81, 0xca, 0x00, 0x04,
+		0xd6, 0xe0, 0x98, 0xda,
+		0x01, 0x08, 0x73, 0x61,
+		0x78, 0x6f, 0x6e, 0x2d,
+		0x70, 0x63, 0x00, 0x00,
+	}
 
+	description := SourceDescription{
+		Header: Header{
+			Version:     2,
+			Padding:     false,
+			ReportCount: 1,
+			Type:        typeSourceDescription,
+		},
+		Chunks: []Chunk{
+			Chunk{
+				SSRC: 3605043418,
+				Items: []SDESItem{
+					SDESItem{
+						Type: typeCName,
+						Text: []byte("saxon-pc"),
+					},
+				},
+			},
+		},
+	}
+	got := description.Bytes()
+	t.Logf("Got: %v\n", got)
+	t.Logf("Expect: %v\n", expect)
+	if !bytes.Equal(got, expect) {
+		t.Errorf("Did not get expected result.\nGot: %v\n Want: %v\n", got, expect)
+	}
 }