Files
livekit/pkg/rtc/transportmanager.go
Raja Subramanian 9e0a7e545f Close both peer connections to aid migration. (#4382)
* Close both peer connections to aid migration.

In single peer connection case, that would close publisher peer
connection.

@cnderrauber I don't remember why we only closed subscriber peer
connection. I am thinking it is okay to close both (or the publisher
peer connection in single peer connection mode). Please let me know if I
am missing something.

* log change only
2026-03-24 14:19:46 +05:30

1033 lines
31 KiB
Go

// Copyright 2023 LiveKit, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package rtc
import (
"context"
"io"
"math/bits"
"sync"
"time"
"github.com/pion/rtcp"
"github.com/pion/sctp"
"github.com/pion/sdp/v3"
"github.com/pion/webrtc/v4"
"github.com/pkg/errors"
"go.uber.org/atomic"
"google.golang.org/protobuf/proto"
"github.com/livekit/mediatransportutil/pkg/twcc"
"github.com/livekit/protocol/livekit"
"github.com/livekit/protocol/logger"
"github.com/livekit/protocol/utils"
"github.com/livekit/livekit-server/pkg/config"
"github.com/livekit/livekit-server/pkg/rtc/transport"
"github.com/livekit/livekit-server/pkg/rtc/types"
"github.com/livekit/livekit-server/pkg/sfu"
"github.com/livekit/livekit-server/pkg/sfu/datachannel"
"github.com/livekit/livekit-server/pkg/sfu/interceptor"
"github.com/livekit/livekit-server/pkg/sfu/pacer"
)
const (
failureCountThreshold = 2
preferNextByFailureWindow = time.Minute
// when RR report loss percentage over this threshold, we consider it is a unstable event
udpLossFracUnstable = 25
// if in last 32 times RR, the unstable report count over this threshold, the connection is unstable
udpLossUnstableCountThreshold = 20
)
// -------------------------------
type TransportManagerTransportHandler struct {
transport.Handler
t *TransportManager
logger logger.Logger
}
func (h TransportManagerTransportHandler) OnFailed(isShortLived bool, iceConnectionInfo *types.ICEConnectionInfo) {
if isShortLived {
h.logger.Infow("short ice connection", connectionDetailsFields([]*types.ICEConnectionInfo{iceConnectionInfo})...)
}
h.t.handleConnectionFailed(isShortLived)
h.Handler.OnFailed(isShortLived, iceConnectionInfo)
}
// -------------------------------
type TransportManagerParams struct {
SubscriberAsPrimary bool
UseSinglePeerConnection bool
Config *WebRTCConfig
Twcc *twcc.Responder
ProtocolVersion types.ProtocolVersion
CongestionControlConfig config.CongestionControlConfig
EnabledSubscribeCodecs []*livekit.Codec
EnabledPublishCodecs []*livekit.Codec
SimTracks map[uint32]interceptor.SimulcastTrackInfo
ClientInfo ClientInfo
Migration bool
AllowTCPFallback bool
TCPFallbackRTTThreshold int
AllowUDPUnstableFallback bool
TURNSEnabled bool
AllowPlayoutDelay bool
DataChannelMaxBufferedAmount uint64
DatachannelSlowThreshold int
DatachannelLossyTargetLatency time.Duration
Logger logger.Logger
PublisherHandler transport.Handler
SubscriberHandler transport.Handler
DataChannelStats *BytesTrackStats
UseOneShotSignallingMode bool
FireOnTrackBySdp bool
EnableDataTracks bool
}
type TransportManager struct {
params TransportManagerParams
lock sync.RWMutex
publisher *PCTransport
subscriber *PCTransport
failureCount int
isTransportReconfigured bool
lastFailure time.Time
lastSignalAt time.Time
signalSourceValid atomic.Bool
pendingOfferPublisher *webrtc.SessionDescription
pendingOfferIdPublisher uint32
pendingDataChannelsPublisher []*livekit.DataChannelInfo
iceConfig *livekit.ICEConfig
mediaLossProxy *MediaLossProxy
udpLossUnstableCount uint32
signalingRTT, udpRTT uint32
onICEConfigChanged func(iceConfig *livekit.ICEConfig)
dataChannelSendErrorDroppedBySlowReaderCount atomic.Uint32
dataChannelSendErrorCount atomic.Uint32
}
func NewTransportManager(params TransportManagerParams) (*TransportManager, error) {
if params.Logger == nil {
params.Logger = logger.GetLogger()
}
t := &TransportManager{
params: params,
mediaLossProxy: NewMediaLossProxy(MediaLossProxyParams{Logger: params.Logger}),
iceConfig: &livekit.ICEConfig{},
}
t.mediaLossProxy.OnMediaLossUpdate(t.onMediaLossUpdate)
lgr := LoggerWithPCTarget(params.Logger, livekit.SignalTarget_PUBLISHER)
publisher, err := NewPCTransport(TransportParams{
ProtocolVersion: params.ProtocolVersion,
Config: params.Config,
Twcc: params.Twcc,
DirectionConfig: params.Config.Publisher,
CongestionControlConfig: params.CongestionControlConfig,
EnabledCodecs: params.EnabledPublishCodecs,
Logger: lgr,
SimTracks: params.SimTracks,
ClientInfo: params.ClientInfo,
IsSendSide: params.UseOneShotSignallingMode || params.UseSinglePeerConnection,
AllowPlayoutDelay: params.AllowPlayoutDelay,
Transport: livekit.SignalTarget_PUBLISHER,
Handler: TransportManagerTransportHandler{params.PublisherHandler, t, lgr},
UseOneShotSignallingMode: params.UseOneShotSignallingMode,
DataChannelMaxBufferedAmount: params.DataChannelMaxBufferedAmount,
DatachannelSlowThreshold: params.DatachannelSlowThreshold,
DatachannelLossyTargetLatency: params.DatachannelLossyTargetLatency,
FireOnTrackBySdp: params.FireOnTrackBySdp,
EnableDataTracks: params.EnableDataTracks,
})
if err != nil {
return nil, err
}
t.publisher = publisher
if !t.params.UseOneShotSignallingMode && !t.params.UseSinglePeerConnection {
lgr := LoggerWithPCTarget(params.Logger, livekit.SignalTarget_SUBSCRIBER)
subscriber, err := NewPCTransport(TransportParams{
ProtocolVersion: params.ProtocolVersion,
Config: params.Config,
DirectionConfig: params.Config.Subscriber,
CongestionControlConfig: params.CongestionControlConfig,
EnabledCodecs: params.EnabledSubscribeCodecs,
Logger: lgr,
ClientInfo: params.ClientInfo,
IsOfferer: true,
IsSendSide: true,
AllowPlayoutDelay: params.AllowPlayoutDelay,
DataChannelMaxBufferedAmount: params.DataChannelMaxBufferedAmount,
DatachannelSlowThreshold: params.DatachannelSlowThreshold,
DatachannelLossyTargetLatency: params.DatachannelLossyTargetLatency,
Transport: livekit.SignalTarget_SUBSCRIBER,
Handler: TransportManagerTransportHandler{params.SubscriberHandler, t, lgr},
FireOnTrackBySdp: params.FireOnTrackBySdp,
EnableDataTracks: params.EnableDataTracks,
})
if err != nil {
return nil, err
}
t.subscriber = subscriber
}
if !t.params.Migration && t.params.SubscriberAsPrimary {
if err := t.createDataChannelsForSubscriber(nil); err != nil {
return nil, err
}
}
t.signalSourceValid.Store(true)
return t, nil
}
func (t *TransportManager) Close() {
if t.publisher != nil {
t.publisher.Close()
}
if t.subscriber != nil {
t.subscriber.Close()
}
}
func (t *TransportManager) HasPublisherEverConnected() bool {
return t.publisher.HasEverConnected()
}
func (t *TransportManager) IsPublisherEstablished() bool {
return t.publisher.IsEstablished()
}
func (t *TransportManager) GetPublisherRTT() (float64, bool) {
return t.publisher.GetRTT()
}
func (t *TransportManager) GetPublisherMid(rtpReceiver *webrtc.RTPReceiver) string {
return t.publisher.GetMid(rtpReceiver)
}
func (t *TransportManager) GetPublisherRTPTransceiver(mid string) *webrtc.RTPTransceiver {
return t.publisher.GetRTPTransceiver(mid)
}
func (t *TransportManager) GetPublisherRTPReceiver(mid string) *webrtc.RTPReceiver {
return t.publisher.GetRTPReceiver(mid)
}
func (t *TransportManager) WritePublisherRTCP(pkts []rtcp.Packet) error {
return t.publisher.WriteRTCP(pkts)
}
func (t *TransportManager) GetSubscriberRTT() (float64, bool) {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
return t.publisher.GetRTT()
} else {
return t.subscriber.GetRTT()
}
}
func (t *TransportManager) HasSubscriberEverConnected() bool {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
return t.publisher.HasEverConnected()
} else {
return t.subscriber.HasEverConnected()
}
}
func (t *TransportManager) AddTrackLocal(
trackLocal webrtc.TrackLocal,
params types.AddTrackParams,
enabledCodecs []*livekit.Codec,
rtcpFeedbackConfig RTCPFeedbackConfig,
) (*webrtc.RTPSender, *webrtc.RTPTransceiver, error) {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
return t.publisher.AddTrack(trackLocal, params, enabledCodecs, rtcpFeedbackConfig)
} else {
return t.subscriber.AddTrack(trackLocal, params, enabledCodecs, rtcpFeedbackConfig)
}
}
func (t *TransportManager) AddTransceiverFromTrackLocal(
trackLocal webrtc.TrackLocal,
params types.AddTrackParams,
enabledCodecs []*livekit.Codec,
rtcpFeedbackConfig RTCPFeedbackConfig,
) (*webrtc.RTPSender, *webrtc.RTPTransceiver, error) {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
return t.publisher.AddTransceiverFromTrack(trackLocal, params, enabledCodecs, rtcpFeedbackConfig)
} else {
return t.subscriber.AddTransceiverFromTrack(trackLocal, params, enabledCodecs, rtcpFeedbackConfig)
}
}
func (t *TransportManager) RemoveTrackLocal(sender *webrtc.RTPSender) error {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
return t.publisher.RemoveTrack(sender)
} else {
return t.subscriber.RemoveTrack(sender)
}
}
func (t *TransportManager) WriteSubscriberRTCP(pkts []rtcp.Packet) error {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
return t.publisher.WriteRTCP(pkts)
} else {
return t.subscriber.WriteRTCP(pkts)
}
}
func (t *TransportManager) GetSubscriberPacer() pacer.Pacer {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
return t.publisher.GetPacer()
} else {
return t.subscriber.GetPacer()
}
}
func (t *TransportManager) AddSubscribedTrack(subTrack types.SubscribedTrack) {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
t.publisher.AddTrackToStreamAllocator(subTrack)
} else {
t.subscriber.AddTrackToStreamAllocator(subTrack)
}
}
func (t *TransportManager) RemoveSubscribedTrack(subTrack types.SubscribedTrack) {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
t.publisher.RemoveTrackFromStreamAllocator(subTrack)
} else {
t.subscriber.RemoveTrackFromStreamAllocator(subTrack)
}
}
func (t *TransportManager) SendDataMessage(kind livekit.DataPacket_Kind, data []byte) error {
// downstream data is sent via primary peer connection
return t.handleSendDataResult(t.getTransport(true).SendDataMessage(kind, data), kind.String(), len(data))
}
func (t *TransportManager) SendDataMessageUnlabeled(data []byte, useRaw bool, sender livekit.ParticipantIdentity) error {
// downstream data is sent via primary peer connection
return t.handleSendDataResult(
t.getTransport(true).SendDataMessageUnlabeled(data, useRaw, sender),
"unlabeled",
len(data),
)
}
func (t *TransportManager) handleSendDataResult(err error, kind string, size int) error {
if err != nil {
if !utils.ErrorIsOneOf(
err,
io.ErrClosedPipe,
sctp.ErrStreamClosed,
ErrTransportFailure,
ErrDataChannelUnavailable,
context.DeadlineExceeded,
datachannel.ErrDataDroppedByHighBufferedAmount,
) {
if errors.Is(err, datachannel.ErrDataDroppedBySlowReader) {
droppedBySlowReaderCount := t.dataChannelSendErrorDroppedBySlowReaderCount.Inc()
if (droppedBySlowReaderCount-1)%100 == 0 {
t.params.Logger.Infow(
"drop data message by slow reader",
"error", err,
"kind", kind,
"count", droppedBySlowReaderCount,
)
}
} else {
count := t.dataChannelSendErrorCount.Inc()
if (count-1)%100 == 0 {
t.params.Logger.Infow(
"send data message error",
"error", err,
"kind", kind,
"count", count,
)
}
}
}
if utils.ErrorIsOneOf(err, sctp.ErrStreamClosed, io.ErrClosedPipe) {
if t.params.SubscriberAsPrimary {
t.params.SubscriberHandler.OnDataSendError(err)
} else {
t.params.PublisherHandler.OnDataSendError(err)
}
}
} else {
t.params.DataChannelStats.AddBytes(uint64(size), true)
}
return err
}
func (t *TransportManager) createDataChannelsForSubscriber(pendingDataChannels []*livekit.DataChannelInfo) error {
var (
reliableID, lossyID, dataTrackID uint16
reliableIDPtr, lossyIDPtr, dataTrackIDPtr *uint16
)
//
// For old version migration clients, they don't send subscriber data channel info
// so we need to create data channels with default ID and don't negotiate as client already has
// data channels with default ID.
//
// For new version migration clients, we create data channels with new ID and negotiate with client
//
for _, dc := range pendingDataChannels {
switch dc.Label {
case ReliableDataChannel:
// pion use step 2 for auto generated ID, so we need to add 6 to avoid conflict
reliableID = uint16(dc.Id) + 6
reliableIDPtr = &reliableID
case LossyDataChannel:
lossyID = uint16(dc.Id) + 6
lossyIDPtr = &lossyID
case DataTrackDataChannel:
dataTrackID = uint16(dc.Id) + 6
dataTrackIDPtr = &dataTrackID
}
}
ordered := true
negotiated := t.params.Migration && reliableIDPtr == nil
if err := t.subscriber.CreateDataChannel(ReliableDataChannel, &webrtc.DataChannelInit{
Ordered: &ordered,
ID: reliableIDPtr,
Negotiated: &negotiated,
}); err != nil {
return err
}
ordered = false
retransmits := uint16(0)
negotiated = t.params.Migration && lossyIDPtr == nil
if err := t.subscriber.CreateDataChannel(LossyDataChannel, &webrtc.DataChannelInit{
Ordered: &ordered,
MaxRetransmits: &retransmits,
ID: lossyIDPtr,
Negotiated: &negotiated,
}); err != nil {
return err
}
negotiated = t.params.Migration && dataTrackIDPtr == nil
if err := t.subscriber.CreateDataChannel(DataTrackDataChannel, &webrtc.DataChannelInit{
Ordered: &ordered,
MaxRetransmits: &retransmits,
ID: dataTrackIDPtr,
Negotiated: &negotiated,
}); err != nil {
return err
}
return nil
}
func (t *TransportManager) GetUnmatchMediaForOffer(parsedOffer *sdp.SessionDescription, mediaType string) (unmatched []*sdp.MediaDescription, err error) {
var lastMatchedMid string
if lastAnswer := t.publisher.CurrentLocalDescription(); lastAnswer != nil {
parsedAnswer, err1 := lastAnswer.Unmarshal()
if err1 != nil {
// should not happen
t.params.Logger.Errorw("failed to parse last answer", err1)
return unmatched, err1
}
for i := len(parsedAnswer.MediaDescriptions) - 1; i >= 0; i-- {
media := parsedAnswer.MediaDescriptions[i]
if media.MediaName.Media == mediaType {
lastMatchedMid, _ = media.Attribute(sdp.AttrKeyMID)
break
}
}
}
for i := len(parsedOffer.MediaDescriptions) - 1; i >= 0; i-- {
media := parsedOffer.MediaDescriptions[i]
if media.MediaName.Media == mediaType {
mid, _ := media.Attribute(sdp.AttrKeyMID)
if mid == lastMatchedMid {
break
}
unmatched = append(unmatched, media)
}
}
return
}
func (t *TransportManager) LastPublisherOffer() *webrtc.SessionDescription {
return t.publisher.CurrentRemoteDescription()
}
func (t *TransportManager) LastPublisherOfferPending() *webrtc.SessionDescription {
return t.publisher.PendingRemoteDescription()
}
func (t *TransportManager) HandleOffer(offer webrtc.SessionDescription, offerId uint32, shouldPend bool) error {
t.lock.Lock()
if shouldPend {
t.pendingOfferPublisher = &offer
t.pendingOfferIdPublisher = offerId
t.lock.Unlock()
return nil
}
t.lock.Unlock()
return t.publisher.HandleRemoteDescription(offer, offerId)
}
func (t *TransportManager) GetAnswer() (webrtc.SessionDescription, uint32, error) {
return t.publisher.GetAnswer()
}
func (t *TransportManager) GetPublisherICESessionUfrag() (string, error) {
return t.publisher.GetICESessionUfrag()
}
func (t *TransportManager) HandleICETrickleSDPFragment(sdpFragment string) error {
return t.publisher.HandleICETrickleSDPFragment(sdpFragment)
}
func (t *TransportManager) HandleICERestartSDPFragment(sdpFragment string) (string, error) {
return t.publisher.HandleICERestartSDPFragment(sdpFragment)
}
func (t *TransportManager) ProcessPendingPublisherOffer() {
t.lock.Lock()
pendingOffer := t.pendingOfferPublisher
t.pendingOfferPublisher = nil
pendingOfferId := t.pendingOfferIdPublisher
t.pendingOfferIdPublisher = 0
t.lock.Unlock()
if pendingOffer != nil {
t.HandleOffer(*pendingOffer, pendingOfferId, false)
}
}
func (t *TransportManager) HandleAnswer(answer webrtc.SessionDescription, answerId uint32) {
t.subscriber.HandleRemoteDescription(answer, answerId)
}
// AddICECandidate adds candidates for remote peer
func (t *TransportManager) AddICECandidate(candidate webrtc.ICECandidateInit, target livekit.SignalTarget) {
switch target {
case livekit.SignalTarget_PUBLISHER:
if t.publisher != nil {
t.publisher.AddICECandidate(candidate)
} else {
t.params.Logger.Warnw("ice candidate for publisher, but no peer connection", nil, "candidate", candidate)
}
case livekit.SignalTarget_SUBSCRIBER:
if t.subscriber != nil {
t.subscriber.AddICECandidate(candidate)
} else {
t.params.Logger.Warnw("ice candidate for subscriber, but no peer connection", nil, "candidate", candidate)
}
default:
err := errors.New("unknown signal target")
t.params.Logger.Errorw("ice candidate for unknown signal target", err, "target", target)
}
}
func (t *TransportManager) NegotiateSubscriber(force bool) {
if t.subscriber != nil {
t.subscriber.Negotiate(force)
} else {
t.publisher.Negotiate(force)
}
}
func (t *TransportManager) HandleClientReconnect(reason livekit.ReconnectReason) {
var (
isShort bool
duration time.Duration
resetShortConnection bool
)
switch reason {
case livekit.ReconnectReason_RR_PUBLISHER_FAILED:
if t.publisher != nil {
resetShortConnection = true
isShort, duration = t.publisher.IsShortConnection(time.Now())
}
case livekit.ReconnectReason_RR_SUBSCRIBER_FAILED:
if t.subscriber != nil {
resetShortConnection = true
isShort, duration = t.subscriber.IsShortConnection(time.Now())
}
}
if isShort {
t.lock.Lock()
t.resetTransportConfigureLocked(false)
t.lock.Unlock()
t.params.Logger.Infow("short connection by client ice restart", "duration", duration, "reason", reason)
t.handleConnectionFailed(isShort)
}
if resetShortConnection {
if t.publisher != nil {
t.publisher.ResetShortConnOnICERestart()
}
if t.subscriber != nil {
t.subscriber.ResetShortConnOnICERestart()
}
}
}
func (t *TransportManager) ICERestart(iceConfig *livekit.ICEConfig) error {
t.SetICEConfig(iceConfig)
if t.subscriber != nil {
return t.subscriber.ICERestart()
}
return nil
}
func (t *TransportManager) OnICEConfigChanged(f func(iceConfig *livekit.ICEConfig)) {
t.lock.Lock()
t.onICEConfigChanged = f
t.lock.Unlock()
}
func (t *TransportManager) SetICEConfig(iceConfig *livekit.ICEConfig) {
if iceConfig != nil {
t.configureICE(iceConfig, true)
}
}
func (t *TransportManager) GetICEConfig() *livekit.ICEConfig {
t.lock.RLock()
defer t.lock.RUnlock()
if t.iceConfig == nil {
return nil
}
return utils.CloneProto(t.iceConfig)
}
func (t *TransportManager) resetTransportConfigureLocked(reconfigured bool) {
t.failureCount = 0
t.isTransportReconfigured = reconfigured
t.udpLossUnstableCount = 0
t.lastFailure = time.Time{}
}
func (t *TransportManager) configureICE(iceConfig *livekit.ICEConfig, reset bool) {
t.lock.Lock()
isEqual := proto.Equal(t.iceConfig, iceConfig)
if reset || !isEqual {
t.resetTransportConfigureLocked(!reset)
}
if isEqual {
t.lock.Unlock()
return
}
t.params.Logger.Infow("setting ICE config", "iceConfig", logger.Proto(iceConfig))
onICEConfigChanged := t.onICEConfigChanged
t.iceConfig = iceConfig
t.lock.Unlock()
if iceConfig.PreferenceSubscriber != livekit.ICECandidateType_ICT_NONE {
t.mediaLossProxy.OnMediaLossUpdate(nil)
}
if t.publisher != nil {
t.publisher.SetPreferTCP(iceConfig.PreferencePublisher == livekit.ICECandidateType_ICT_TCP)
}
if t.subscriber != nil {
t.subscriber.SetPreferTCP(iceConfig.PreferenceSubscriber == livekit.ICECandidateType_ICT_TCP)
}
if onICEConfigChanged != nil {
onICEConfigChanged(iceConfig)
}
}
func (t *TransportManager) SubscriberAsPrimary() bool {
return t.params.SubscriberAsPrimary
}
func (t *TransportManager) GetICEConnectionInfo() []*types.ICEConnectionInfo {
infos := make([]*types.ICEConnectionInfo, 0, 2)
for _, pc := range []*PCTransport{t.publisher, t.subscriber} {
if pc == nil {
continue
}
info := pc.GetICEConnectionInfo()
if info.HasCandidates() {
infos = append(infos, info)
}
}
return infos
}
func (t *TransportManager) GetDataTrackTransport() types.DataTrackTransport {
return t.getTransport(true)
}
func (t *TransportManager) getTransport(isPrimary bool) *PCTransport {
switch {
case t.publisher == nil:
return t.subscriber
case t.subscriber == nil:
return t.publisher
default:
pcTransport := t.publisher
if (isPrimary && t.params.SubscriberAsPrimary) || (!isPrimary && !t.params.SubscriberAsPrimary) {
pcTransport = t.subscriber
}
return pcTransport
}
}
func (t *TransportManager) getLowestPriorityConnectionType() types.ICEConnectionType {
switch {
case t.publisher == nil:
return t.subscriber.GetICEConnectionType()
case t.subscriber == nil:
return t.publisher.GetICEConnectionType()
default:
ctype := t.publisher.GetICEConnectionType()
if stype := t.subscriber.GetICEConnectionType(); stype > ctype {
ctype = stype
}
return ctype
}
}
func (t *TransportManager) handleConnectionFailed(isShortLived bool) {
if !t.params.AllowTCPFallback || t.params.UseOneShotSignallingMode {
return
}
t.lock.Lock()
if t.isTransportReconfigured {
t.lock.Unlock()
return
}
lastSignalSince := time.Since(t.lastSignalAt)
signalValid := t.signalSourceValid.Load()
if !t.hasRecentSignalLocked() || !signalValid {
// the failed might cause by network interrupt because signal closed or we have not seen any signal in the time window,
// so don't switch to next candidate type
t.params.Logger.Debugw(
"ignoring prefer candidate check by ICE failure because signal connection interrupted",
"lastSignalSince", lastSignalSince,
"signalValid", signalValid,
)
t.failureCount = 0
t.lastFailure = time.Time{}
t.lock.Unlock()
return
}
lowestPriorityConnectionType := t.getLowestPriorityConnectionType()
//
// Checking only `PreferenceSubscriber` field although any connection failure (PUBLISHER OR SUBSCRIBER) will
// flow through here.
//
// As both transports are switched to the same type on any failure, checking just subscriber should be fine.
//
getNext := func(ic *livekit.ICEConfig) livekit.ICECandidateType {
switch lowestPriorityConnectionType {
case types.ICEConnectionTypeUDP:
// try ICE/TCP if ICE/UDP failed
if ic.PreferenceSubscriber == livekit.ICECandidateType_ICT_NONE {
if t.params.ClientInfo.SupportsICETCP() && t.canUseICETCP() {
return livekit.ICECandidateType_ICT_TCP
} else if t.params.TURNSEnabled {
// fallback to TURN/TLS if TCP is not supported
return livekit.ICECandidateType_ICT_TLS
}
}
case types.ICEConnectionTypeTCP:
// try TURN/TLS if ICE/TCP failed,
// the configuration could have been ICT_NONE or ICT_TCP,
// in either case, fallback to TURN/TLS
if t.params.TURNSEnabled {
return livekit.ICECandidateType_ICT_TLS
} else {
// keep the current config
return ic.PreferenceSubscriber
}
case types.ICEConnectionTypeTURN:
// TURN/TLS is the most permissive option, if that fails there is nowhere to go to
// the configuration could have been ICT_NONE or ICT_TLS,
// keep the current config
return ic.PreferenceSubscriber
}
return livekit.ICECandidateType_ICT_NONE
}
var preferNext livekit.ICECandidateType
if isShortLived {
preferNext = getNext(t.iceConfig)
} else {
t.failureCount++
lastFailure := t.lastFailure
t.lastFailure = time.Now()
if t.failureCount < failureCountThreshold || time.Since(lastFailure) > preferNextByFailureWindow {
t.lock.Unlock()
return
}
preferNext = getNext(t.iceConfig)
}
if preferNext == t.iceConfig.PreferenceSubscriber {
t.lock.Unlock()
return
}
t.isTransportReconfigured = true
t.lock.Unlock()
switch preferNext {
case livekit.ICECandidateType_ICT_TCP:
t.params.Logger.Debugw("prefer TCP transport on both peer connections")
case livekit.ICECandidateType_ICT_TLS:
t.params.Logger.Debugw("prefer TLS transport both peer connections")
case livekit.ICECandidateType_ICT_NONE:
t.params.Logger.Debugw("allowing all transports on both peer connections")
}
// irrespective of which one fails, force prefer candidate on both as the other one might
// fail at a different time and cause another disruption
t.configureICE(&livekit.ICEConfig{
PreferenceSubscriber: preferNext,
PreferencePublisher: preferNext,
}, false)
}
func (t *TransportManager) SetMigrateInfo(
previousOffer *webrtc.SessionDescription,
previousAnswer *webrtc.SessionDescription,
dataChannels []*livekit.DataChannelInfo,
) {
t.lock.Lock()
t.pendingDataChannelsPublisher = make([]*livekit.DataChannelInfo, 0, len(dataChannels))
pendingDataChannelsSubscriber := make([]*livekit.DataChannelInfo, 0, len(dataChannels))
for _, dci := range dataChannels {
if dci.Target == livekit.SignalTarget_SUBSCRIBER {
pendingDataChannelsSubscriber = append(pendingDataChannelsSubscriber, dci)
} else {
t.pendingDataChannelsPublisher = append(t.pendingDataChannelsPublisher, dci)
}
}
t.lock.Unlock()
if t.params.SubscriberAsPrimary {
if err := t.createDataChannelsForSubscriber(pendingDataChannelsSubscriber); err != nil {
t.params.Logger.Errorw("create subscriber data channels during migration failed", err)
}
}
if t.params.UseSinglePeerConnection {
t.publisher.SetPreviousSdp(previousAnswer, previousOffer)
} else {
t.subscriber.SetPreviousSdp(previousOffer, previousAnswer)
}
}
func (t *TransportManager) ProcessPendingPublisherDataChannels() {
t.lock.Lock()
pendingDataChannels := t.pendingDataChannelsPublisher
t.pendingDataChannelsPublisher = nil
t.lock.Unlock()
ordered := true
negotiated := true
for _, ci := range pendingDataChannels {
var (
dcLabel string
dcID uint16
dcExisting bool
err error
)
switch ci.Label {
case ReliableDataChannel:
id := uint16(ci.GetId())
dcLabel, dcID, dcExisting, err = t.publisher.CreateDataChannelIfEmpty(ReliableDataChannel, &webrtc.DataChannelInit{
Ordered: &ordered,
Negotiated: &negotiated,
ID: &id,
})
case LossyDataChannel:
ordered = false
retransmits := uint16(0)
id := uint16(ci.GetId())
dcLabel, dcID, dcExisting, err = t.publisher.CreateDataChannelIfEmpty(LossyDataChannel, &webrtc.DataChannelInit{
Ordered: &ordered,
MaxRetransmits: &retransmits,
Negotiated: &negotiated,
ID: &id,
})
case DataTrackDataChannel:
ordered = false
retransmits := uint16(0)
id := uint16(ci.GetId())
dcLabel, dcID, dcExisting, err = t.publisher.CreateDataChannelIfEmpty(DataTrackDataChannel, &webrtc.DataChannelInit{
Ordered: &ordered,
MaxRetransmits: &retransmits,
Negotiated: &negotiated,
ID: &id,
})
}
if err != nil {
t.params.Logger.Errorw("create migrated data channel failed", err, "label", ci.Label)
} else if dcExisting {
t.params.Logger.Debugw("existing data channel during migration", "label", dcLabel, "id", dcID)
} else {
t.params.Logger.Debugw("create migrated data channel", "label", dcLabel, "id", dcID)
}
}
}
func (t *TransportManager) HandleReceiverReport(dt *sfu.DownTrack, report *rtcp.ReceiverReport) {
t.mediaLossProxy.HandleMaxLossFeedback(dt, report)
}
func (t *TransportManager) onMediaLossUpdate(loss uint8) {
if t.params.TCPFallbackRTTThreshold == 0 || !t.params.AllowUDPUnstableFallback {
return
}
t.lock.Lock()
t.udpLossUnstableCount <<= 1
if loss >= uint8(255*udpLossFracUnstable/100) {
t.udpLossUnstableCount |= 1
if bits.OnesCount32(t.udpLossUnstableCount) >= udpLossUnstableCountThreshold {
if t.udpRTT > 0 && t.signalingRTT < uint32(float32(t.udpRTT)*1.3) && int(t.signalingRTT) < t.params.TCPFallbackRTTThreshold && t.hasRecentSignalLocked() {
t.udpLossUnstableCount = 0
t.lock.Unlock()
t.params.Logger.Infow("udp connection unstable, switch to tcp", "signalingRTT", t.signalingRTT)
if t.params.UseSinglePeerConnection {
t.params.PublisherHandler.OnFailed(true, t.publisher.GetICEConnectionInfo())
} else {
t.params.SubscriberHandler.OnFailed(true, t.subscriber.GetICEConnectionInfo())
}
return
}
}
}
t.lock.Unlock()
}
func (t *TransportManager) UpdateSignalingRTT(rtt uint32) {
t.lock.Lock()
t.signalingRTT = rtt
t.lock.Unlock()
if t.publisher != nil {
t.publisher.SetSignalingRTT(rtt)
}
if t.subscriber != nil {
t.subscriber.SetSignalingRTT(rtt)
}
// TODO: considering using tcp rtt to calculate ice connection cost, if ice connection can't be established
// within 5 * tcp rtt(at least 5s), means udp traffic might be block/dropped, switch to tcp.
// Currently, most cases reported is that ice connected but subsequent connection, so left the thinking for now.
}
func (t *TransportManager) UpdateMediaRTT(rtt uint32) {
t.lock.Lock()
if t.udpRTT == 0 {
t.udpRTT = rtt
} else {
t.udpRTT = uint32(int(t.udpRTT) + (int(rtt)-int(t.udpRTT))/2)
}
t.lock.Unlock()
}
func (t *TransportManager) UpdateLastSeenSignal() {
t.lock.Lock()
t.lastSignalAt = time.Now()
t.lock.Unlock()
}
func (t *TransportManager) SinceLastSignal() time.Duration {
t.lock.RLock()
defer t.lock.RUnlock()
return time.Since(t.lastSignalAt)
}
func (t *TransportManager) LastSeenSignalAt() time.Time {
t.lock.RLock()
defer t.lock.RUnlock()
return t.lastSignalAt
}
func (t *TransportManager) canUseICETCP() bool {
return t.params.TCPFallbackRTTThreshold == 0 || int(t.signalingRTT) < t.params.TCPFallbackRTTThreshold
}
func (t *TransportManager) SetSignalSourceValid(valid bool) {
t.signalSourceValid.Store(valid)
t.params.Logger.Debugw("signal source valid", "valid", valid)
}
func (t *TransportManager) SetSubscriberAllowPause(allowPause bool) {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
t.publisher.SetAllowPauseOfStreamAllocator(allowPause)
} else {
t.subscriber.SetAllowPauseOfStreamAllocator(allowPause)
}
}
func (t *TransportManager) SetSubscriberChannelCapacity(channelCapacity int64) {
if t.params.UseOneShotSignallingMode || t.params.UseSinglePeerConnection {
t.publisher.SetChannelCapacityOfStreamAllocator(channelCapacity)
} else {
t.subscriber.SetChannelCapacityOfStreamAllocator(channelCapacity)
}
}
func (t *TransportManager) hasRecentSignalLocked() bool {
return time.Since(t.lastSignalAt) < PingTimeoutSeconds*time.Second
}
func (t *TransportManager) RTPStreamPublished(ssrc uint32, mid, rid string) {
t.publisher.RTPStreamPublished(ssrc, mid, rid)
}