mediamtx/internal/protocols/webrtc/peer_connection_test.go

package webrtc

import (
	"net"
	"regexp"
	"sort"
	"strings"
	"testing"
	"time"

	"github.com/pion/ice/v4"
	"github.com/pion/logging"
	"github.com/pion/rtcp"
	"github.com/pion/rtp"
	"github.com/pion/sdp/v3"
	"github.com/pion/webrtc/v4"
	"github.com/stretchr/testify/require"

	"github.com/bluenviron/mediamtx/internal/test"
)

type nilWriter struct{}

func (nilWriter) Write(p []byte) (int, error) {
	return len(p), nil
}

var webrtcNilLogger = logging.NewDefaultLeveledLoggerForScope("", 0, &nilWriter{})

func gatherCodecs(tracks []*InboundTrack) []webrtc.RTPCodecParameters {
	codecs := make([]webrtc.RTPCodecParameters, len(tracks))
	for i, track := range tracks {
		codecs[i] = track.Codec()
	}
	return codecs
}

func gatherTrackIDs(tracks []*InboundTrack) []string {
	ids := make([]string, len(tracks))
	for i, track := range tracks {
		ids[i] = track.track.ID()
	}
	return ids
}

func gatherTrackRIDs(tracks []*InboundTrack) []string {
	rids := make([]string, len(tracks))
	for i, track := range tracks {
		rids[i] = track.track.RID()
	}
	return rids
}

func gatherTrackMIDIndexes(tracks []*InboundTrack) []int {
	mids := make([]int, len(tracks))
	for i, track := range tracks {
		mids[i] = track.midIndex
	}
	return mids
}

func gatherTrackRIDIndexes(tracks []*InboundTrack) []int {
	rids := make([]int, len(tracks))
	for i, track := range tracks {
		rids[i] = track.ridIndex
	}
	return rids
}

func senderHeaderExtensionID(params webrtc.RTPSendParameters, uri string) uint8 {
	for _, ext := range params.HeaderExtensions {
		if ext.URI == uri {
			return uint8(ext.ID)
		}
	}
	return 0
}

func TestPeerConnectionCloseImmediately(t *testing.T) {
	pc := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           false,
		Log:               test.NilLogger,
	}
	err := pc.Start()
	require.NoError(t, err)
	defer pc.Close()
}

func TestPeerConnectionCloseImmediately2(t *testing.T) {
	pc := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           false,
		Log:               test.NilLogger,
	}
	err := pc.Start()
	require.NoError(t, err)
	defer pc.Close()

	_, err = pc.CreatePartialOffer(false)
	require.NoError(t, err)

	// wait for ICE candidates to be generated
	time.Sleep(500 * time.Millisecond)
}

func TestPeerConnectionCandidates(t *testing.T) {
	for _, ca := range []string{
		"udp random",
		"udp",
		"tcp",
		"stun",
		"udp+stun",
		"udp random+stun",
	} {
		t.Run(ca, func(t *testing.T) {
			pc2, err := webrtc.NewPeerConnection(webrtc.Configuration{})
			require.NoError(t, err)
			defer pc2.Close() //nolint:errcheck

			track, err := webrtc.NewTrackLocalStaticRTP(
				webrtc.RTPCodecCapability{
					MimeType:  webrtc.MimeTypeVP8,
					ClockRate: 90000,
				},
				"video",
				"publisher",
			)
			require.NoError(t, err)

			_, err = pc2.AddTrack(track)
			require.NoError(t, err)

			offer, err := pc2.CreateOffer(nil)
			require.NoError(t, err)

			var udpMux ice.UDPMux
			if ca == "udp" || ca == "udp+stun" {
				var ln net.PacketConn
				ln, err = net.ListenPacket("udp", ":3454")
				require.NoError(t, err)
				defer ln.Close()
				udpMux = webrtc.NewICEUDPMux(webrtcNilLogger, ln)
			}

			var tcpMux *TCPMuxWrapper
			if ca == "tcp" {
				var ln net.Listener
				ln, err = net.Listen("tcp", ":3454")
				require.NoError(t, err)
				defer ln.Close()
				tcpMux = &TCPMuxWrapper{
					Mux: webrtc.NewICETCPMux(webrtcNilLogger, ln, 8),
					Ln:  ln,
				}
			}

			pc := &PeerConnection{
				LocalRandomUDP:        (ca == "udp random" || ca == "udp random+stun"),
				ICEUDPMux:             udpMux,
				ICETCPMux:             tcpMux,
				SupportsIPv6:          true,
				IPsFromInterfaces:     true,
				IPsFromInterfacesList: []string{"lo"},
				Log:                   test.NilLogger,
			}

			if ca == "stun" || ca == "udp+stun" || ca == "udp random+stun" {
				pc.ICEServers = []webrtc.ICEServer{{
					URLs: []string{"stun:stun.l.google.com:19302"},
				}}
			}

			err = pc.Start()
			require.NoError(t, err)
			defer pc.Close()

			answer, err := pc.CreateFullAnswer(&offer, false)
			require.NoError(t, err)

			n := len(regexp.MustCompile("(?m)^a=candidate:.+? udp .+? typ host").FindAllString(answer.SDP, -1))
			if ca == "udp" || ca == "udp random" || ca == "udp+stun" || ca == "udp random+stun" {
				require.Equal(t, 2, n)
			} else {
				require.Equal(t, 0, n)
			}

			n = len(regexp.MustCompile("(?m)^a=candidate:.+? tcp .+? typ host tcptype passive").FindAllString(answer.SDP, -1))
			if ca == "tcp" {
				require.Equal(t, 2, n)
			} else {
				require.Equal(t, 0, n)
			}

			n = len(regexp.MustCompile("(?m)^a=candidate:.+? udp .+? typ srflx").FindAllString(answer.SDP, -1))
			if ca == "stun" || ca == "udp+stun" || ca == "udp random+stun" {
				require.Equal(t, 2, n)
			} else {
				require.Equal(t, 0, n)
			}
		})
	}
}

func TestPeerConnectionCandidatesIPv6Disabled(t *testing.T) {
	pc2, err := webrtc.NewPeerConnection(webrtc.Configuration{})
	require.NoError(t, err)
	defer pc2.Close() //nolint:errcheck

	track, err := webrtc.NewTrackLocalStaticRTP(
		webrtc.RTPCodecCapability{
			MimeType:  webrtc.MimeTypeVP8,
			ClockRate: 90000,
		},
		"video",
		"publisher",
	)
	require.NoError(t, err)

	_, err = pc2.AddTrack(track)
	require.NoError(t, err)

	offer, err := pc2.CreateOffer(nil)
	require.NoError(t, err)

	pc := &PeerConnection{
		SupportsIPv6:          false,
		IPsFromInterfaces:     true,
		IPsFromInterfacesList: []string{"lo"},
		Log:                   test.NilLogger,
	}

	err = pc.Start()
	require.NoError(t, err)
	defer pc.Close()

	answer, err := pc.CreateFullAnswer(&offer, false)
	require.NoError(t, err)

	require.NotContains(t, answer.SDP, " udp6 ")
	require.NotContains(t, answer.SDP, " tcp6 ")
}

func TestPeerConnectionConnectivity(t *testing.T) {
	for _, mode := range []string{
		"passive udp",
		"passive tcp",
		"active udp",
		"active udp + stun",
	} {
		for _, ip := range []string{
			"from interfaces",
			"additional hosts",
		} {
			// LocalRandomUDP doesn't work with AdditionalHosts
			// we don't care since we are not currently using them together
			if mode == "active udp" && ip == "additional hosts" {
				continue
			}

			t.Run(mode+"_"+ip, func(t *testing.T) {
				var iceServers []webrtc.ICEServer

				if mode == "active udp + stun" {
					iceServers = []webrtc.ICEServer{{
						URLs: []string{"stun:stun.l.google.com:19302"},
					}}
				}

				clientPC := &PeerConnection{
					LocalRandomUDP:        (mode == "passive udp" || mode == "active udp"),
					IPsFromInterfaces:     true,
					IPsFromInterfacesList: []string{"lo"},
					ICEServers:            iceServers,
					Log:                   test.NilLogger,
				}
				err := clientPC.Start()
				require.NoError(t, err)
				defer clientPC.Close()

				var udpMux ice.UDPMux
				var tcpMux *TCPMuxWrapper

				switch mode {
				case "passive udp":
					var ln net.PacketConn
					ln, err = net.ListenPacket("udp4", ":4458")
					require.NoError(t, err)
					defer ln.Close()
					udpMux = webrtc.NewICEUDPMux(webrtcNilLogger, ln)

				case "passive tcp":
					var ln net.Listener
					ln, err = net.Listen("tcp4", ":4458")
					require.NoError(t, err)
					defer ln.Close()
					tcpMux = &TCPMuxWrapper{
						Mux: webrtc.NewICETCPMux(webrtcNilLogger, ln, 8),
						Ln:  ln,
					}
				}

				serverPC := &PeerConnection{
					LocalRandomUDP: (mode == "active udp"),
					ICEUDPMux:      udpMux,
					ICETCPMux:      tcpMux,
					ICEServers:     iceServers,
					Publish:        true,
					OutboundTracks: []*OutboundTrack{{
						Caps: webrtc.RTPCodecCapability{
							MimeType:  webrtc.MimeTypeAV1,
							ClockRate: 90000,
						},
					}},
					Log: test.NilLogger,
				}

				if ip == "from interfaces" {
					serverPC.IPsFromInterfaces = true
					serverPC.IPsFromInterfacesList = []string{"lo"}
				} else {
					serverPC.AdditionalHosts = []string{"127.0.0.1"}
				}

				err = serverPC.Start()
				require.NoError(t, err)
				defer serverPC.Close()

				offer, err := clientPC.CreatePartialOffer(false)
				require.NoError(t, err)

				answer, err := serverPC.CreateFullAnswer(offer, false)
				require.NoError(t, err)

				require.Equal(t, 2, strings.Count(answer.SDP, "a=candidate:"))

				err = clientPC.SetAnswer(answer)
				require.NoError(t, err)

				go func() {
					for {
						select {
						case cd := <-clientPC.NewLocalCandidate():
							err2 := serverPC.AddRemoteCandidate(cd)
							require.NoError(t, err2)

						case <-clientPC.Failed():
							return
						}
					}
				}()

				err = serverPC.WaitUntilConnected(10 * time.Second)
				require.NoError(t, err)
			})
		}
	}
}

func TestPeerConnectionRead(t *testing.T) {
	pub, err := webrtc.NewPeerConnection(webrtc.Configuration{})
	require.NoError(t, err)
	defer pub.Close() //nolint:errcheck

	videoTrack, err := webrtc.NewTrackLocalStaticRTP(
		webrtc.RTPCodecCapability{
			MimeType:  webrtc.MimeTypeVP8,
			ClockRate: 90000,
		},
		"video",
		"publisher")
	require.NoError(t, err)

	videoSender, err := pub.AddTrack(videoTrack)
	require.NoError(t, err)

	audioTrack, err := webrtc.NewTrackLocalStaticRTP(
		webrtc.RTPCodecCapability{
			MimeType:  webrtc.MimeTypeOpus,
			ClockRate: 48000,
		},
		"audio",
		"publisher")
	require.NoError(t, err)

	audioSender, err := pub.AddTrack(audioTrack)
	require.NoError(t, err)

	reader := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           false,
		Log:               test.NilLogger,
	}
	err = reader.Start()
	require.NoError(t, err)
	defer reader.Close()

	offer, err := pub.CreateOffer(nil)
	require.NoError(t, err)

	err = pub.SetLocalDescription(offer)
	require.NoError(t, err)

	answer, err := reader.CreateFullAnswer(&offer, false)
	require.NoError(t, err)

	err = pub.SetRemoteDescription(*answer)
	require.NoError(t, err)

	err = reader.WaitUntilConnected(10 * time.Second)
	require.NoError(t, err)

	go func() {
		time.Sleep(100 * time.Millisecond)

		err2 := audioTrack.WriteRTP(&rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         true,
				PayloadType:    111,
				SequenceNumber: 1123,
				Timestamp:      45343,
				SSRC:           563424,
			},
			Payload: []byte{5, 2},
		})
		require.NoError(t, err2)

		err2 = videoTrack.WriteRTP(&rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         true,
				PayloadType:    111,
				SequenceNumber: 1123,
				Timestamp:      45343,
				SSRC:           563424,
			},
			Payload: []byte{5, 2},
		})
		require.NoError(t, err2)
	}()

	err = reader.GatherInboundTracks(2 * time.Second)
	require.NoError(t, err)

	require.Equal(t, []string{"video", "audio"}, gatherTrackIDs(reader.InboundTracks()))
	require.Equal(t, []int{0, 1}, gatherTrackMIDIndexes(reader.InboundTracks()))

	codecs := gatherCodecs(reader.InboundTracks())

	sort.Slice(codecs, func(i, j int) bool {
		return codecs[i].PayloadType < codecs[j].PayloadType
	})

	require.Equal(t, []webrtc.RTPCodecParameters{
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{
				MimeType:     webrtc.MimeTypeVP8,
				ClockRate:    90000,
				RTCPFeedback: codecs[0].RTCPFeedback,
			},
			PayloadType: 96,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{
				MimeType:     webrtc.MimeTypeOpus,
				ClockRate:    48000,
				Channels:     2,
				SDPFmtpLine:  "minptime=10;useinbandfec=1",
				RTCPFeedback: codecs[1].RTCPFeedback,
			},
			PayloadType: 111,
		},
	}, codecs)

	reader.StartReading()

	pkts, _, err := videoSender.ReadRTCP()
	require.NoError(t, err)
	require.Equal(t, []rtcp.Packet{
		&rtcp.ReceiverReport{
			SSRC: pkts[0].(*rtcp.ReceiverReport).SSRC,
			Reports: []rtcp.ReceptionReport{{
				SSRC:               uint32(videoSender.GetParameters().Encodings[0].SSRC),
				LastSequenceNumber: pkts[0].(*rtcp.ReceiverReport).Reports[0].LastSequenceNumber,
				LastSenderReport:   pkts[0].(*rtcp.ReceiverReport).Reports[0].LastSenderReport,
				Delay:              pkts[0].(*rtcp.ReceiverReport).Reports[0].Delay,
			}},
			ProfileExtensions: []byte{},
		},
	}, pkts)

	pkts, _, err = audioSender.ReadRTCP()
	require.NoError(t, err)
	require.Equal(t, []rtcp.Packet{
		&rtcp.ReceiverReport{
			SSRC: pkts[0].(*rtcp.ReceiverReport).SSRC,
			Reports: []rtcp.ReceptionReport{{
				SSRC:               uint32(audioSender.GetParameters().Encodings[0].SSRC),
				LastSequenceNumber: pkts[0].(*rtcp.ReceiverReport).Reports[0].LastSequenceNumber,
				LastSenderReport:   pkts[0].(*rtcp.ReceiverReport).Reports[0].LastSenderReport,
				Delay:              pkts[0].(*rtcp.ReceiverReport).Reports[0].Delay,
			}},
			ProfileExtensions: []byte{},
		},
	}, pkts)
}

func TestPeerConnectionReadSimulcast(t *testing.T) {
	pub, err := webrtc.NewPeerConnection(webrtc.Configuration{})
	require.NoError(t, err)
	defer pub.Close() //nolint:errcheck

	videoTrackL, err := webrtc.NewTrackLocalStaticRTP(
		webrtc.RTPCodecCapability{
			MimeType:  webrtc.MimeTypeVP8,
			ClockRate: 90000,
		},
		"video", "publisher",
		webrtc.WithRTPStreamID("l"),
	)
	require.NoError(t, err)

	videoTrackM, err := webrtc.NewTrackLocalStaticRTP(
		webrtc.RTPCodecCapability{
			MimeType:  webrtc.MimeTypeVP8,
			ClockRate: 90000,
		},
		"video", "publisher",
		webrtc.WithRTPStreamID("m"),
	)
	require.NoError(t, err)

	videoTrackH, err := webrtc.NewTrackLocalStaticRTP(
		webrtc.RTPCodecCapability{
			MimeType:  webrtc.MimeTypeVP8,
			ClockRate: 90000,
		},
		"video", "publisher",
		webrtc.WithRTPStreamID("h"),
	)
	require.NoError(t, err)

	transceiver, err := pub.AddTransceiverFromTrack(videoTrackL, webrtc.RTPTransceiverInit{
		Direction: webrtc.RTPTransceiverDirectionSendonly,
		SendEncodings: []webrtc.RTPEncodingParameters{
			{RTPCodingParameters: webrtc.RTPCodingParameters{RID: "l"}},
			{RTPCodingParameters: webrtc.RTPCodingParameters{RID: "m"}},
			{RTPCodingParameters: webrtc.RTPCodingParameters{RID: "h"}},
		},
	})
	require.NoError(t, err)

	err = transceiver.Sender().AddEncoding(videoTrackM)
	require.NoError(t, err)

	err = transceiver.Sender().AddEncoding(videoTrackH)
	require.NoError(t, err)

	reader := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           false,
		Log:               test.NilLogger,
	}
	err = reader.Start()
	require.NoError(t, err)
	defer reader.Close()

	offer, err := pub.CreateOffer(nil)
	require.NoError(t, err)

	err = pub.SetLocalDescription(offer)
	require.NoError(t, err)

	answer, err := reader.CreateFullAnswer(&offer, false)
	require.NoError(t, err)

	err = pub.SetRemoteDescription(*answer)
	require.NoError(t, err)

	err = reader.WaitUntilConnected(10 * time.Second)
	require.NoError(t, err)

	params := transceiver.Sender().GetParameters()
	midExtID := senderHeaderExtensionID(params, sdp.SDESMidURI)
	ridExtID := senderHeaderExtensionID(params, sdp.SDESRTPStreamIDURI)
	require.NotZero(t, midExtID)
	require.NotZero(t, ridExtID)

	mid := transceiver.Mid()

	go func() {
		time.Sleep(200 * time.Millisecond)

		layers := []struct {
			track  *webrtc.TrackLocalStaticRTP
			rid    string
			ssrc   uint32
			seqNum uint16
		}{
			{videoTrackL, "l", 100001, 1000},
			{videoTrackM, "m", 100002, 2000},
			{videoTrackH, "h", 100003, 3000},
		}

		for i, layer := range layers {
			pkt := &rtp.Packet{
				Header: rtp.Header{
					Version:        2,
					Marker:         true,
					PayloadType:    96,
					SequenceNumber: layer.seqNum,
					Timestamp:      45343,
					SSRC:           layer.ssrc,
				},
				Payload: []byte{5, 2},
			}

			pkt.ExtensionProfile = 0xBEDE
			require.NoError(t, pkt.SetExtension(midExtID, []byte(mid)))
			require.NoError(t, pkt.SetExtension(ridExtID, []byte(layer.rid)))

			err2 := layer.track.WriteRTP(pkt)
			if err2 != nil {
				return
			}
			layers[i].seqNum++
		}
	}()

	err = reader.GatherInboundTracks(5 * time.Second)
	require.NoError(t, err)

	tracks := reader.InboundTracks()
	codecs := gatherCodecs(tracks)

	require.Equal(t, 3, len(codecs))

	for _, codec := range codecs {
		require.Equal(t, webrtc.RTPCodecCapability{
			MimeType:     webrtc.MimeTypeVP8,
			ClockRate:    90000,
			RTCPFeedback: codec.RTCPFeedback,
		}, codec.RTPCodecCapability)
	}

	require.Equal(t, []string{"l", "m", "h"}, gatherTrackRIDs(tracks))
	require.Equal(t, []int{0, 1, 2}, gatherTrackRIDIndexes(tracks))
}

func TestPeerConnectionStripIncomingTWCC(t *testing.T) {
	pub, err := webrtc.NewPeerConnection(webrtc.Configuration{})
	require.NoError(t, err)
	defer pub.Close() //nolint:errcheck

	videoTrack, err := webrtc.NewTrackLocalStaticRTP(
		webrtc.RTPCodecCapability{
			MimeType:  webrtc.MimeTypeVP8,
			ClockRate: 90000,
		},
		"video", "publisher",
		webrtc.WithRTPStreamID("l"),
	)
	require.NoError(t, err)

	videoSender, err := pub.AddTrack(videoTrack)
	require.NoError(t, err)

	reader := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           false,
		Log:               test.NilLogger,
	}
	err = reader.Start()
	require.NoError(t, err)
	defer reader.Close()

	offer, err := pub.CreateOffer(nil)
	require.NoError(t, err)

	err = pub.SetLocalDescription(offer)
	require.NoError(t, err)

	answer, err := reader.CreateFullAnswer(&offer, false)
	require.NoError(t, err)

	err = pub.SetRemoteDescription(*answer)
	require.NoError(t, err)

	err = reader.WaitUntilConnected(10 * time.Second)
	require.NoError(t, err)

	params := videoSender.GetParameters()
	twccExtID := senderHeaderExtensionID(params, twccExtensionURI)
	require.NotZero(t, twccExtID)

	go func() {
		time.Sleep(200 * time.Millisecond)

		pkt := &rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         true,
				PayloadType:    96,
				SequenceNumber: 55421,
				Timestamp:      45343,
				SSRC:           124123,
			},
			Payload: []byte{5, 2},
		}

		pkt.ExtensionProfile = 0xBEDE
		require.NoError(t, pkt.SetExtension(twccExtID, []byte{0x12, 0x34}))

		err2 := videoTrack.WriteRTP(pkt)
		if err2 != nil {
			return
		}
	}()

	err = reader.GatherInboundTracks(5 * time.Second)
	require.NoError(t, err)

	tracks := reader.InboundTracks()
	require.Len(t, tracks, 1)

	done := make(chan struct{})

	tracks[0].OnPacketRTP = func(p *rtp.Packet) {
		require.False(t, p.Extension)
		require.Empty(t, p.Extensions)
		close(done)
	}

	reader.StartReading()

	<-done
}

func TestPeerConnectionPublishRead(t *testing.T) {
	pc1 := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           false,
		Log:               test.NilLogger,
	}
	err := pc1.Start()
	require.NoError(t, err)
	defer pc1.Close()

	pc2 := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           true,
		OutboundTracks: []*OutboundTrack{
			{
				Caps: webrtc.RTPCodecCapability{
					MimeType:  webrtc.MimeTypeH264,
					ClockRate: 90000,
				},
			},
			{
				Caps: webrtc.RTPCodecCapability{
					MimeType:  webrtc.MimeTypeOpus,
					ClockRate: 48000,
					Channels:  2,
				},
			},
		},
		Log: test.NilLogger,
	}
	err = pc2.Start()
	require.NoError(t, err)
	defer pc2.Close()

	offer, err := pc1.CreatePartialOffer(false)
	require.NoError(t, err)

	answer, err := pc2.CreateFullAnswer(offer, false)
	require.NoError(t, err)

	err = pc1.SetAnswer(answer)
	require.NoError(t, err)

	err = pc1.WaitUntilConnected(10 * time.Second)
	require.NoError(t, err)

	err = pc2.WaitUntilConnected(10 * time.Second)
	require.NoError(t, err)

	for _, track := range pc2.OutboundTracks {
		err = track.WriteRTP(&rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         true,
				PayloadType:    111,
				SequenceNumber: 1123,
				Timestamp:      45343,
				SSRC:           563424,
			},
			Payload: []byte{5, 2},
		})
		require.NoError(t, err)
	}

	err = pc1.GatherInboundTracks(2 * time.Second)
	require.NoError(t, err)

	codecs := gatherCodecs(pc1.InboundTracks())

	sort.Slice(codecs, func(i, j int) bool {
		return codecs[i].PayloadType < codecs[j].PayloadType
	})

	require.Equal(t, []webrtc.RTPCodecParameters{
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{
				MimeType:     webrtc.MimeTypeH264,
				ClockRate:    90000,
				SDPFmtpLine:  "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f",
				RTCPFeedback: codecs[0].RTCPFeedback,
			},
			PayloadType: 105,
		},
		{
			RTPCodecCapability: webrtc.RTPCodecCapability{
				MimeType:     webrtc.MimeTypeOpus,
				ClockRate:    48000,
				Channels:     2,
				SDPFmtpLine:  "minptime=10;useinbandfec=1;stereo=1;sprop-stereo=1",
				RTCPFeedback: codecs[1].RTCPFeedback,
			},
			PayloadType: 111,
		},
	}, codecs)
}

// test that an audio codec is present regardless of the fact that an audio track is.
func TestPeerConnectionFallbackCodecs(t *testing.T) {
	pc1 := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           false,
		Log:               test.NilLogger,
	}
	err := pc1.Start()
	require.NoError(t, err)
	defer pc1.Close()

	pc2 := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           true,
		OutboundTracks: []*OutboundTrack{{
			Caps: webrtc.RTPCodecCapability{
				MimeType:  webrtc.MimeTypeAV1,
				ClockRate: 90000,
			},
		}},
		Log: test.NilLogger,
	}
	err = pc2.Start()
	require.NoError(t, err)
	defer pc2.Close()

	offer, err := pc1.CreatePartialOffer(false)
	require.NoError(t, err)

	answer, err := pc2.CreateFullAnswer(offer, false)
	require.NoError(t, err)

	var s sdp.SessionDescription
	err = s.Unmarshal([]byte(answer.SDP))
	require.NoError(t, err)

	require.Equal(t, []*sdp.MediaDescription{
		{
			MediaName: sdp.MediaName{
				Media:   "video",
				Port:    sdp.RangedPort{Value: 9},
				Protos:  []string{"UDP", "TLS", "RTP", "SAVPF"},
				Formats: []string{"97"},
			},
			ConnectionInformation: s.MediaDescriptions[0].ConnectionInformation,
			Attributes:            s.MediaDescriptions[0].Attributes,
		},
		{
			MediaName: sdp.MediaName{
				Media:   "audio",
				Port:    sdp.RangedPort{Value: 9},
				Protos:  []string{"UDP", "TLS", "RTP", "SAVPF"},
				Formats: []string{"0"},
			},
			ConnectionInformation: s.MediaDescriptions[1].ConnectionInformation,
			Attributes:            s.MediaDescriptions[1].Attributes,
		},
	}, s.MediaDescriptions)
}

func TestPeerConnectionPublishDataChannel(t *testing.T) {
	pc1, err := webrtc.NewPeerConnection(webrtc.Configuration{})
	require.NoError(t, err)
	defer pc1.Close() //nolint:errcheck

	_, err = pc1.CreateDataChannel("", nil)
	require.NoError(t, err)

	dataChanOpened := make(chan struct{})
	dataReceived := make(chan struct{})

	pc1.OnDataChannel(func(dc *webrtc.DataChannel) {
		dc.OnOpen(func() {
			close(dataChanOpened)
		})

		dc.OnMessage(func(msg webrtc.DataChannelMessage) {
			require.Equal(t, []byte("test data"), msg.Data)
			close(dataReceived)
		})
	})

	offer, err := pc1.CreateOffer(nil)
	require.NoError(t, err)

	err = pc1.SetLocalDescription(offer)
	require.NoError(t, err)

	pc2 := &PeerConnection{
		LocalRandomUDP:    true,
		IPsFromInterfaces: true,
		Publish:           true,
		OutboundDataChannels: []*OutboundDataChannel{
			{
				Label: "test-channel",
			},
		},
		Log: test.NilLogger,
	}
	err = pc2.Start()
	require.NoError(t, err)
	defer pc2.Close()

	outboundDataChanOpened := make(chan struct{})

	pc2.OutboundDataChannels[0].dataChan.OnOpen(func() {
		close(outboundDataChanOpened)
	})

	answer, err := pc2.CreateFullAnswer(&offer, false)
	require.NoError(t, err)

	err = pc1.SetRemoteDescription(*answer)
	require.NoError(t, err)

	err = pc2.WaitUntilConnected(10 * time.Second)
	require.NoError(t, err)

	<-outboundDataChanOpened
	<-dataChanOpened

	err = pc2.OutboundDataChannels[0].dataChan.Send([]byte("test data"))
	require.NoError(t, err)

	<-dataReceived
}

func TestPeerConnectionAdditionalHostsUnresolvable(t *testing.T) {
	// A host in AdditionalHosts that can't be resolved server-side - for
	// instance air-gapped networks without DNS, or split-horizon / overlay
	// DNS names that only resolve on the client - must be skipped instead of
	// aborting the session; the other (valid) entries must still produce
	// candidates.
	clientPC := &PeerConnection{
		LocalRandomUDP:        true,
		IPsFromInterfaces:     true,
		IPsFromInterfacesList: []string{"lo"},
		Log:                   test.NilLogger,
	}
	err := clientPC.Start()
	require.NoError(t, err)
	defer clientPC.Close()

	ln, err := net.ListenPacket("udp4", ":0")
	require.NoError(t, err)
	defer ln.Close()
	udpMux := webrtc.NewICEUDPMux(webrtcNilLogger, ln)

	serverPC := &PeerConnection{
		ICEUDPMux:       udpMux,
		AdditionalHosts: []string{"127.0.0.1", "unresolvable.invalid"},
		Publish:         true,
		OutboundTracks: []*OutboundTrack{{
			Caps: webrtc.RTPCodecCapability{
				MimeType:  webrtc.MimeTypeAV1,
				ClockRate: 90000,
			},
		}},
		Log: test.NilLogger,
	}
	err = serverPC.Start()
	require.NoError(t, err)
	defer serverPC.Close()

	offer, err := clientPC.CreatePartialOffer(false)
	require.NoError(t, err)

	answer, err := serverPC.CreateFullAnswer(offer, false)
	require.NoError(t, err)

	require.Contains(t, answer.SDP, "127.0.0.1")
	require.NotContains(t, answer.SDP, "unresolvable.invalid")
}

func TestPeerConnectionRecomputeSequenceNumber(t *testing.T) {
	for _, ca := range []struct {
		name          string
		packets       []*rtp.Packet
		expectedCount int
		check         func(t *testing.T, seqNums []uint16)
	}{
		{
			name: "skip empty packets",
			packets: []*rtp.Packet{
				{
					Header: rtp.Header{
						Version:        2,
						Marker:         true,
						PayloadType:    96,
						SequenceNumber: 1000,
						Timestamp:      45343,
						SSRC:           124123,
					},
					Payload: []byte{5, 2},
				},
				{
					Header: rtp.Header{
						Version:        2,
						Marker:         true,
						PayloadType:    96,
						SequenceNumber: 1001,
						Timestamp:      45343,
						SSRC:           124123,
					},
					Payload: []byte{},
				},
				{
					Header: rtp.Header{
						Version:        2,
						Marker:         true,
						PayloadType:    96,
						SequenceNumber: 1002,
						Timestamp:      45343,
						SSRC:           124123,
					},
					Payload: []byte{5, 2},
				},
				{
					Header: rtp.Header{
						Version:        2,
						Marker:         true,
						PayloadType:    96,
						SequenceNumber: 1003,
						Timestamp:      45343,
						SSRC:           124123,
					},
					Payload: []byte{},
				},
				{
					Header: rtp.Header{
						Version:        2,
						Marker:         true,
						PayloadType:    96,
						SequenceNumber: 1004,
						Timestamp:      45343,
						SSRC:           124123,
					},
					Payload: []byte{5, 2},
				},
			},
			expectedCount: 3,
			check: func(t *testing.T, seqNums []uint16) {
				require.Len(t, seqNums, 3)
				require.Equal(t, seqNums[1], seqNums[0]+1)
				require.Equal(t, seqNums[2], seqNums[1]+1)
			},
		},
		{
			name: "preserve real gaps",
			packets: func() []*rtp.Packet {
				packets := []*rtp.Packet{{
					Header: rtp.Header{
						Version:        2,
						Marker:         true,
						PayloadType:    96,
						SequenceNumber: 1000,
						Timestamp:      45343,
						SSRC:           124123,
					},
					Payload: []byte{5, 2},
				}}

				for i := uint16(1002); i <= 1065; i++ {
					packets = append(packets, &rtp.Packet{
						Header: rtp.Header{
							Version:        2,
							Marker:         true,
							PayloadType:    96,
							SequenceNumber: i,
							Timestamp:      45343,
							SSRC:           124123,
						},
						Payload: []byte{5, 2},
					})
				}

				return packets
			}(),
			expectedCount: 2,
			check: func(t *testing.T, seqNums []uint16) {
				require.Len(t, seqNums, 2)
				require.Equal(t, seqNums[1], seqNums[0]+2)
			},
		},
	} {
		t.Run(ca.name, func(t *testing.T) {
			pub, err := webrtc.NewPeerConnection(webrtc.Configuration{})
			require.NoError(t, err)
			defer pub.Close() //nolint:errcheck

			videoTrack, err := webrtc.NewTrackLocalStaticRTP(
				webrtc.RTPCodecCapability{
					MimeType:  webrtc.MimeTypeVP8,
					ClockRate: 90000,
				},
				"video", "publisher",
			)
			require.NoError(t, err)

			_, err = pub.AddTrack(videoTrack)
			require.NoError(t, err)

			reader := &PeerConnection{
				LocalRandomUDP:    true,
				IPsFromInterfaces: true,
				Publish:           false,
				Log:               test.NilLogger,
			}
			err = reader.Start()
			require.NoError(t, err)
			defer reader.Close()

			offer, err := pub.CreateOffer(nil)
			require.NoError(t, err)

			err = pub.SetLocalDescription(offer)
			require.NoError(t, err)

			answer, err := reader.CreateFullAnswer(&offer, false)
			require.NoError(t, err)

			err = pub.SetRemoteDescription(*answer)
			require.NoError(t, err)

			err = reader.WaitUntilConnected(10 * time.Second)
			require.NoError(t, err)

			go func() {
				time.Sleep(200 * time.Millisecond)

				for _, pkt := range ca.packets {
					err2 := videoTrack.WriteRTP(pkt)
					if err2 != nil {
						return
					}
				}
			}()

			err = reader.GatherInboundTracks(5 * time.Second)
			require.NoError(t, err)

			tracks := reader.InboundTracks()
			require.Len(t, tracks, 1)

			received := make(chan []uint16, 1)
			var seqNums []uint16

			tracks[0].OnPacketRTP = func(p *rtp.Packet) {
				require.NotEmpty(t, p.Payload)
				seqNums = append(seqNums, p.SequenceNumber)
				if len(seqNums) == ca.expectedCount {
					received <- append([]uint16(nil), seqNums...)
				}
			}

			reader.StartReading()

			select {
			case seqs := <-received:
				ca.check(t, seqs)

			case <-time.After(2 * time.Second):
				require.FailNow(t, "timeout waiting for packets")
			}
		})
	}
}