mirror of https://bitbucket.org/ausocean/av.git
151 lines
3.2 KiB
Go
151 lines
3.2 KiB
Go
package rtp
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import (
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"fmt"
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"net"
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)
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const (
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RTP_VERSION = 2
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)
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const (
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hasRtpPadding = 1 << 2
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hasRtpExt = 1 << 3
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)
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// Packet as per https://tools.ietf.org/html/rfc1889#section-5.1
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//
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// 0 1 2 3
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// |V=2|P|X| CC |M| PT | sequence number |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | timestamp |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | synchronization source (SSRC) identifier |
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// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
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// | contributing source (CSRC) identifiers |
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// | .... |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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type RtpPacket struct {
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Version byte
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Padding bool
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Ext bool
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Marker bool
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PayloadType byte
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SequenceNumber uint
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Timestamp uint
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SyncSource uint
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CSRC []uint
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ExtHeader uint
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ExtData []byte
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Payload []byte
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}
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type Session struct {
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Rtp net.PacketConn
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Rtcp net.PacketConn
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RtpChan <-chan RtpPacket
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RtcpChan <-chan []byte
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rtpChan chan<- RtpPacket
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rtcpChan chan<- []byte
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}
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func New(rtp, rtcp net.PacketConn) *Session {
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rtpChan := make(chan RtpPacket, 10)
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rtcpChan := make(chan []byte, 10)
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s := &Session{
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Rtp: rtp,
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Rtcp: rtcp,
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RtpChan: rtpChan,
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RtcpChan: rtcpChan,
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rtpChan: rtpChan,
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rtcpChan: rtcpChan,
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}
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go s.HandleRtpConn(rtp)
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go s.HandleRtcpConn(rtcp)
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return s
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}
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func toUint(arr []byte) (ret uint) {
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for i, b := range arr {
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ret |= uint(b) << (8 * uint(len(arr)-i-1))
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}
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return ret
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}
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func (s *Session) HandleRtpConn(conn net.PacketConn) {
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buf := make([]byte, 4096)
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for {
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n, _, err := conn.ReadFrom(buf)
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if err != nil {
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panic(err)
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}
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cpy := make([]byte, n)
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copy(cpy, buf)
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go s.handleRtp(cpy)
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}
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}
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func (s *Session) HandleRtcpConn(conn net.PacketConn) {
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buf := make([]byte, 4096)
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for {
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n, _, err := conn.ReadFrom(buf)
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if err != nil {
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panic(err)
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}
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cpy := make([]byte, n)
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copy(cpy, buf)
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go s.handleRtcp(cpy)
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}
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}
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func (s *Session) handleRtp(buf []byte) {
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packet := RtpPacket{
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Version: buf[0] & 0x03,
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Padding: buf[0]&hasRtpPadding != 0,
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Ext: buf[0]&hasRtpExt != 0,
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CSRC: make([]uint, buf[0]>>4),
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Marker: buf[1]&1 != 0,
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PayloadType: buf[1] >> 1,
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SequenceNumber: toUint(buf[2:4]),
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Timestamp: toUint(buf[4:8]),
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SyncSource: toUint(buf[8:12]),
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}
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if packet.Version != RTP_VERSION {
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fmt.Printf("version: %v\n", packet.Version)
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}
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i := 12
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for j := range packet.CSRC {
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packet.CSRC[j] = toUint(buf[i : i+4])
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i += 4
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}
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if packet.Ext {
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packet.ExtHeader = toUint(buf[i : i+2])
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length := toUint(buf[i+2 : i+4])
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i += 4
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if length > 0 {
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packet.ExtData = buf[i : i+int(length)*4]
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i += int(length) * 4
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}
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}
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packet.Payload = buf[i:]
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s.rtpChan <- packet
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}
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func (s *Session) handleRtcp(buf []byte) {
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// TODO: implement rtcp
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}
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