snapshot of https://github.com/pion/webrtc.git (main, 2026-09-15; blobs > 131072B omitted)

sdpsemantics_test.go

@@ -0,0 +1,385 @@
+// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+//go:build !js
+
+package webrtc
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/pion/sdp/v3"
+	"github.com/pion/transport/v4/test"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSDPSemantics_String(t *testing.T) {
+	testCases := []struct {
+		value          SDPSemantics
+		expectedString string
+	}{
+		{SDPSemanticsUnifiedPlanWithFallback, "unified-plan-with-fallback"},
+		{SDPSemanticsPlanB, "plan-b"},
+		{SDPSemanticsUnifiedPlan, "unified-plan"},
+	}
+
+	assert.Equal(t,
+		ErrUnknownType.Error(),
+		SDPSemantics(42).String(),
+	)
+
+	for i, testCase := range testCases {
+		assert.Equal(t,
+			testCase.expectedString,
+			testCase.value.String(),
+			"testCase: %d %v", i, testCase,
+		)
+		assert.Equal(t,
+			testCase.value,
+			newSDPSemantics(testCase.expectedString),
+			"testCase: %d %v", i, testCase,
+		)
+	}
+}
+
+func TestSDPSemantics_JSON(t *testing.T) {
+	testCases := []struct {
+		value SDPSemantics
+		JSON  []byte
+	}{
+		{SDPSemanticsUnifiedPlanWithFallback, []byte("\"unified-plan-with-fallback\"")},
+		{SDPSemanticsPlanB, []byte("\"plan-b\"")},
+		{SDPSemanticsUnifiedPlan, []byte("\"unified-plan\"")},
+	}
+
+	for i, testCase := range testCases {
+		res, err := json.Marshal(testCase.value)
+		assert.NoError(t, err)
+		assert.Equal(t,
+			testCase.JSON,
+			res,
+			"testCase: %d %v", i, testCase,
+		)
+
+		var v SDPSemantics
+		err = json.Unmarshal(testCase.JSON, &v)
+		assert.NoError(t, err)
+		assert.Equal(t, v, testCase.value)
+	}
+}
+
+// The following tests are for non-standard SDP semantics
+// (i.e. not unified-unified)
+
+func getMdNames(sdp *sdp.SessionDescription) []string {
+	mdNames := make([]string, 0, len(sdp.MediaDescriptions))
+	for _, media := range sdp.MediaDescriptions {
+		mdNames = append(mdNames, media.MediaName.Media)
+	}
+
+	return mdNames
+}
+
+func extractSsrcList(md *sdp.MediaDescription) []string {
+	ssrcMap := map[string]struct{}{}
+	for _, attr := range md.Attributes {
+		if attr.Key == sdp.AttrKeySSRC {
+			ssrc := strings.Fields(attr.Value)[0]
+			ssrcMap[ssrc] = struct{}{}
+		}
+	}
+	ssrcList := make([]string, 0, len(ssrcMap))
+	for ssrc := range ssrcMap {
+		ssrcList = append(ssrcList, ssrc)
+	}
+
+	return ssrcList
+}
+
+func TestSDPSemantics_PlanBOfferTransceivers(t *testing.T) {
+	report := test.CheckRoutines(t)
+	defer report()
+
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	opc, err := NewPeerConnection(Configuration{
+		SDPSemantics: SDPSemanticsPlanB,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeVideo, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionSendrecv,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeVideo, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionSendrecv,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeAudio, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionSendrecv,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeAudio, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionSendrecv,
+	})
+	assert.NoError(t, err)
+
+	offer, err := opc.CreateOffer(nil)
+	assert.NoError(t, err)
+
+	mdNames := getMdNames(offer.parsed)
+	assert.ObjectsAreEqual(mdNames, []string{"video", "audio", "data"})
+
+	// Verify that each section has 2 SSRCs (one for each transceiver)
+	for _, section := range []string{"video", "audio"} {
+		for _, media := range offer.parsed.MediaDescriptions {
+			if media.MediaName.Media == section {
+				assert.Len(t, extractSsrcList(media), 2)
+			}
+		}
+	}
+
+	apc, err := NewPeerConnection(Configuration{
+		SDPSemantics: SDPSemanticsPlanB,
+	})
+	assert.NoError(t, err)
+
+	assert.NoError(t, apc.SetRemoteDescription(offer))
+
+	answer, err := apc.CreateAnswer(nil)
+	assert.NoError(t, err)
+
+	mdNames = getMdNames(answer.parsed)
+	assert.ObjectsAreEqual(mdNames, []string{"video", "audio", "data"})
+
+	closePairNow(t, apc, opc)
+}
+
+func TestSDPSemantics_PlanBAnswerSenders(t *testing.T) {
+	report := test.CheckRoutines(t)
+	defer report()
+
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	opc, err := NewPeerConnection(Configuration{
+		SDPSemantics: SDPSemanticsPlanB,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeVideo, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionRecvonly,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeAudio, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionRecvonly,
+	})
+	assert.NoError(t, err)
+
+	offer, err := opc.CreateOffer(nil)
+	assert.NoError(t, err)
+
+	assert.ObjectsAreEqual(getMdNames(offer.parsed), []string{"video", "audio", "data"})
+
+	apc, err := NewPeerConnection(Configuration{
+		SDPSemantics: SDPSemanticsPlanB,
+	})
+	assert.NoError(t, err)
+
+	video1, err := NewTrackLocalStaticSample(RTPCodecCapability{
+		MimeType:    MimeTypeH264,
+		SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f",
+	}, "1", "1")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(video1)
+	assert.NoError(t, err)
+
+	video2, err := NewTrackLocalStaticSample(RTPCodecCapability{
+		MimeType:    MimeTypeH264,
+		SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f",
+	}, "2", "2")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(video2)
+	assert.NoError(t, err)
+
+	audio1, err := NewTrackLocalStaticSample(RTPCodecCapability{MimeType: MimeTypeOpus}, "3", "3")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(audio1)
+	assert.NoError(t, err)
+
+	audio2, err := NewTrackLocalStaticSample(RTPCodecCapability{MimeType: MimeTypeOpus}, "4", "4")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(audio2)
+	assert.NoError(t, err)
+
+	assert.NoError(t, apc.SetRemoteDescription(offer))
+
+	answer, err := apc.CreateAnswer(nil)
+	assert.NoError(t, err)
+
+	assert.ObjectsAreEqual(getMdNames(answer.parsed), []string{"video", "audio", "data"})
+
+	// Verify that each section has 2 SSRCs (one for each sender)
+	for _, section := range []string{"video", "audio"} {
+		for _, media := range answer.parsed.MediaDescriptions {
+			if media.MediaName.Media == section {
+				assert.Lenf(t, extractSsrcList(media), 2, "%q should have 2 SSRCs in Plan-B mode", section)
+			}
+		}
+	}
+
+	closePairNow(t, apc, opc)
+}
+
+func TestSDPSemantics_UnifiedPlanWithFallback(t *testing.T) {
+	report := test.CheckRoutines(t)
+	defer report()
+
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	opc, err := NewPeerConnection(Configuration{
+		SDPSemantics: SDPSemanticsPlanB,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeVideo, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionRecvonly,
+	})
+	assert.NoError(t, err)
+
+	_, err = opc.AddTransceiverFromKind(RTPCodecTypeAudio, RTPTransceiverInit{
+		Direction: RTPTransceiverDirectionRecvonly,
+	})
+	assert.NoError(t, err)
+
+	offer, err := opc.CreateOffer(nil)
+	assert.NoError(t, err)
+
+	assert.ObjectsAreEqual(getMdNames(offer.parsed), []string{"video", "audio", "data"})
+
+	apc, err := NewPeerConnection(Configuration{
+		SDPSemantics: SDPSemanticsUnifiedPlanWithFallback,
+	})
+	assert.NoError(t, err)
+
+	video1, err := NewTrackLocalStaticSample(RTPCodecCapability{
+		MimeType:    MimeTypeH264,
+		SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f",
+	}, "1", "1")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(video1)
+	assert.NoError(t, err)
+
+	video2, err := NewTrackLocalStaticSample(RTPCodecCapability{
+		MimeType:    MimeTypeH264,
+		SDPFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f",
+	}, "2", "2")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(video2)
+	assert.NoError(t, err)
+
+	audio1, err := NewTrackLocalStaticSample(RTPCodecCapability{MimeType: MimeTypeOpus}, "3", "3")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(audio1)
+	assert.NoError(t, err)
+
+	audio2, err := NewTrackLocalStaticSample(RTPCodecCapability{MimeType: MimeTypeOpus}, "4", "4")
+	assert.NoError(t, err)
+
+	_, err = apc.AddTrack(audio2)
+	assert.NoError(t, err)
+
+	assert.NoError(t, apc.SetRemoteDescription(offer))
+
+	answer, err := apc.CreateAnswer(nil)
+	assert.NoError(t, err)
+
+	assert.ObjectsAreEqual(getMdNames(answer.parsed), []string{"video", "audio", "data"})
+
+	extractSsrcList := func(md *sdp.MediaDescription) []string {
+		ssrcMap := map[string]struct{}{}
+		for _, attr := range md.Attributes {
+			if attr.Key == sdp.AttrKeySSRC {
+				ssrc := strings.Fields(attr.Value)[0]
+				ssrcMap[ssrc] = struct{}{}
+			}
+		}
+		ssrcList := make([]string, 0, len(ssrcMap))
+		for ssrc := range ssrcMap {
+			ssrcList = append(ssrcList, ssrc)
+		}
+
+		return ssrcList
+	}
+	// Verify that each section has 2 SSRCs (one for each sender).
+	for _, section := range []string{"video", "audio"} {
+		for _, media := range answer.parsed.MediaDescriptions {
+			if media.MediaName.Media == section {
+				assert.Lenf(t, extractSsrcList(media), 2, "%q should have 2 SSRCs in Plan-B fallback mode", section)
+			}
+		}
+	}
+
+	closePairNow(t, apc, opc)
+}
+
+// Assert that we can catch Remote SessionDescription that don't match our Semantics.
+func TestSDPSemantics_SetRemoteDescription_Mismatch(t *testing.T) {
+	//nolint:lll
+	planBOffer := "v=0\r\no=- 4648475892259889561 3 IN IP4 127.0.0.1\r\ns=-\r\nt=0 0\r\na=group:BUNDLE video audio\r\na=ice-ufrag:1hhfzwf0ijpzm\r\na=ice-pwd:jm5puo2ab1op3vs59ca53bdk7s\r\na=fingerprint:sha-256 40:42:FB:47:87:52:BF:CB:EC:3A:DF:EB:06:DA:2D:B7:2F:59:42:10:23:7B:9D:4C:C9:58:DD:FF:A2:8F:17:67\r\nm=video 9 UDP/TLS/RTP/SAVPF 96\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=setup:passive\r\na=mid:video\r\na=sendonly\r\na=rtcp-mux\r\na=rtpmap:96 H264/90000\r\na=rtcp-fb:96 nack\r\na=rtcp-fb:96 goog-remb\r\na=fmtp:96 packetization-mode=1;profile-level-id=42e01f\r\na=ssrc:1505338584 cname:10000000b5810aac\r\na=ssrc:1 cname:trackB\r\nm=audio 9 UDP/TLS/RTP/SAVPF 111\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=setup:passive\r\na=mid:audio\r\na=sendonly\r\na=rtcp-mux\r\na=rtpmap:111 opus/48000/2\r\na=ssrc:697641945 cname:10000000b5810aac\r\n"
+	//nolint:lll
+	unifiedPlanOffer := "v=0\r\no=- 4648475892259889561 3 IN IP4 127.0.0.1\r\ns=-\r\nt=0 0\r\na=group:BUNDLE 0 1\r\na=ice-ufrag:1hhfzwf0ijpzm\r\na=ice-pwd:jm5puo2ab1op3vs59ca53bdk7s\r\na=fingerprint:sha-256 40:42:FB:47:87:52:BF:CB:EC:3A:DF:EB:06:DA:2D:B7:2F:59:42:10:23:7B:9D:4C:C9:58:DD:FF:A2:8F:17:67\r\nm=video 9 UDP/TLS/RTP/SAVPF 96\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=setup:passive\r\na=mid:0\r\na=sendonly\r\na=rtcp-mux\r\na=rtpmap:96 H264/90000\r\na=rtcp-fb:96 nack\r\na=rtcp-fb:96 goog-remb\r\na=fmtp:96 packetization-mode=1;profile-level-id=42e01f\r\na=ssrc:1505338584 cname:10000000b5810aac\r\nm=audio 9 UDP/TLS/RTP/SAVPF 111\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=setup:passive\r\na=mid:1\r\na=sendonly\r\na=rtcp-mux\r\na=rtpmap:111 opus/48000/2\r\na=ssrc:697641945 cname:10000000b5810aac\r\n"
+
+	report := test.CheckRoutines(t)
+	defer report()
+
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	t.Run("PlanB", func(t *testing.T) {
+		pc, err := NewPeerConnection(Configuration{
+			SDPSemantics: SDPSemanticsUnifiedPlan,
+		})
+		assert.NoError(t, err)
+
+		err = pc.SetRemoteDescription(SessionDescription{SDP: planBOffer, Type: SDPTypeOffer})
+		assert.NoError(t, err)
+
+		_, err = pc.CreateAnswer(nil)
+		assert.True(t, errors.Is(err, ErrIncorrectSDPSemantics))
+
+		assert.NoError(t, pc.Close())
+	})
+
+	t.Run("UnifiedPlan", func(t *testing.T) {
+		pc, err := NewPeerConnection(Configuration{
+			SDPSemantics: SDPSemanticsPlanB,
+		})
+		assert.NoError(t, err)
+
+		err = pc.SetRemoteDescription(SessionDescription{SDP: unifiedPlanOffer, Type: SDPTypeOffer})
+		assert.NoError(t, err)
+
+		_, err = pc.CreateAnswer(nil)
+		assert.True(t, errors.Is(err, ErrIncorrectSDPSemantics))
+
+		assert.NoError(t, pc.Close())
+	})
+}