106 lines
2.4 KiB
Go
106 lines
2.4 KiB
Go
package main
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import (
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"bytes"
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"encoding/binary"
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"encoding/hex"
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"io"
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"log"
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"net"
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)
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// RTPRelay holds information on the relaying stream listener
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type RTPRelay struct {
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close bool
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targetIP net.IP
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targetPort int
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}
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// CreateRTPRelay creates a UDP listener that handles live data
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// from the camera and forwards it as an RTP stream
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func CreateRTPRelay(targetAddress net.IP, targetPort int) RTPRelay {
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conn, err := net.ListenPacket("udp", ":6669")
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if err != nil {
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log.Printf("ERROR: %s\n", err)
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}
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relay := RTPRelay{
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targetIP: targetAddress,
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targetPort: targetPort,
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}
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if err != nil {
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log.Printf("ERROR: %s\n", err)
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}
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go handleCameraStream(relay, conn)
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return relay
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}
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func handleCameraStream(relay RTPRelay, conn net.PacketConn) {
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buffer := make([]byte, 2048)
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header := StreamHeader{}
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var payload []byte
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rtpTarget := net.UDPAddr{
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IP: relay.targetIP,
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Port: relay.targetPort,
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}
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rtpSource, _ := net.ResolveUDPAddr("udp", "127.0.0.1:5000")
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rtpConn, _ := net.DialUDP("udp", rtpSource, &rtpTarget)
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var sequenceNumber uint16
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var elapsed uint32
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frameBuffer := []byte{}
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for {
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conn.ReadFrom(buffer)
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packetReader := bytes.NewReader(buffer)
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binary.Read(packetReader, binary.BigEndian, &header)
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if header.Magic != 0xBCDE {
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log.Printf("Received message with invalid magic (%x).", header.Magic)
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break
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}
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if header.Length > 0 {
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payload = make([]byte, header.Length)
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bytesRead, err := io.ReadFull(packetReader, payload)
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if err != nil {
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log.Printf("Read Error: %s, %d bytes\n", err, bytesRead)
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break
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}
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} else {
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payload = []byte{}
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}
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switch header.MessageType {
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case 0x0001: // H.264 Data
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frameBuffer = append(frameBuffer, payload...)
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case 0x0002: // Time
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packet := bytes.Buffer{}
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packet.Write([]byte{0x80, 0x63})
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binary.Write(&packet, binary.BigEndian, sequenceNumber)
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binary.Write(&packet, binary.BigEndian, (uint32)(elapsed*90))
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binary.Write(&packet, binary.BigEndian, (uint64(0)))
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packet.Write(frameBuffer)
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rtpConn.Write(packet.Bytes())
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frameBuffer = []byte{}
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sequenceNumber++
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elapsed = binary.LittleEndian.Uint32(payload[12:])
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//log.Printf("Elapsed: %d (%x)\n", elapsed, payload[12:])
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default:
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log.Printf("Received Unknown Message: %+v\n", header)
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log.Printf("Payload:\n%s\n", hex.Dump(payload))
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}
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if relay.close {
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break
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}
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}
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}
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// Stop stops listening for packets
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func (r *RTPRelay) Stop() {
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r.close = true
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}
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