Adding upstream version 125.0.1.upstream/125.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

15 files changed, 643 insertions, 228 deletions

diff --git a/dom/media/webrtc/jsapi/MediaTransportHandler.cpp b/dom/media/webrtc/jsapi/MediaTransportHandler.cpp
index 3ee95f36f6..cf95ef41d6 100644
--- a/dom/media/webrtc/jsapi/MediaTransportHandler.cpp
+++ b/dom/media/webrtc/jsapi/MediaTransportHandler.cpp
@@ -156,9 +156,9 @@ class MediaTransportHandlerSTS : public MediaTransportHandler,
   using MediaTransportHandler::OnRtcpStateChange;
   using MediaTransportHandler::OnStateChange;
 
-  void OnGatheringStateChange(NrIceCtx* aIceCtx,
-                              NrIceCtx::GatheringState aState);
-  void OnConnectionStateChange(NrIceCtx* aIceCtx,
+  void OnGatheringStateChange(const std::string& aTransportId,
+                              NrIceMediaStream::GatheringState aState);
+  void OnConnectionStateChange(NrIceMediaStream* aIceStream,
                                NrIceCtx::ConnectionState aState);
   void OnCandidateFound(NrIceMediaStream* aStream,
                         const std::string& aCandidate,
@@ -589,8 +589,6 @@ void MediaTransportHandlerSTS::CreateIceCtx(const std::string& aName) {
                                                     __func__);
               }
 
-              mIceCtx->SignalGatheringStateChange.connect(
-                  this, &MediaTransportHandlerSTS::OnGatheringStateChange);
               mIceCtx->SignalConnectionStateChange.connect(
                   this, &MediaTransportHandlerSTS::OnConnectionStateChange);
 
@@ -784,6 +782,8 @@ void MediaTransportHandlerSTS::EnsureProvisionalTransport(
 
           stream->SignalCandidate.connect(
               this, &MediaTransportHandlerSTS::OnCandidateFound);
+          stream->SignalGatheringStateChange.connect(
+              this, &MediaTransportHandlerSTS::OnGatheringStateChange);
         }
 
         // Begins an ICE restart if this stream has a different ufrag/pwd
@@ -1181,31 +1181,31 @@ void MediaTransportHandler::OnAlpnNegotiated(const std::string& aAlpn) {
 }
 
 void MediaTransportHandler::OnGatheringStateChange(
-    dom::RTCIceGatheringState aState) {
+    const std::string& aTransportId, dom::RTCIceGathererState aState) {
   if (mCallbackThread && !mCallbackThread->IsOnCurrentThread()) {
     mCallbackThread->Dispatch(
         // This is being called from sigslot, which does not hold a strong ref.
         WrapRunnable(this, &MediaTransportHandler::OnGatheringStateChange,
-                     aState),
+                     aTransportId, aState),
         NS_DISPATCH_NORMAL);
     return;
   }
 
-  SignalGatheringStateChange(aState);
+  SignalGatheringStateChange(aTransportId, aState);
 }
 
 void MediaTransportHandler::OnConnectionStateChange(
-    dom::RTCIceConnectionState aState) {
+    const std::string& aTransportId, dom::RTCIceTransportState aState) {
   if (mCallbackThread && !mCallbackThread->IsOnCurrentThread()) {
     mCallbackThread->Dispatch(
         // This is being called from sigslot, which does not hold a strong ref.
         WrapRunnable(this, &MediaTransportHandler::OnConnectionStateChange,
-                     aState),
+                     aTransportId, aState),
         NS_DISPATCH_NORMAL);
     return;
   }
 
-  SignalConnectionStateChange(aState);
+  SignalConnectionStateChange(aTransportId, aState);
 }
 
 void MediaTransportHandler::OnPacketReceived(const std::string& aTransportId,
@@ -1583,48 +1583,48 @@ RefPtr<TransportFlow> MediaTransportHandlerSTS::CreateTransportFlow(
   return flow;
 }
 
-static mozilla::dom::RTCIceGatheringState toDomIceGatheringState(
-    NrIceCtx::GatheringState aState) {
+static mozilla::dom::RTCIceGathererState toDomIceGathererState(
+    NrIceMediaStream::GatheringState aState) {
   switch (aState) {
-    case NrIceCtx::ICE_CTX_GATHER_INIT:
-      return dom::RTCIceGatheringState::New;
-    case NrIceCtx::ICE_CTX_GATHER_STARTED:
-      return dom::RTCIceGatheringState::Gathering;
-    case NrIceCtx::ICE_CTX_GATHER_COMPLETE:
-      return dom::RTCIceGatheringState::Complete;
+    case NrIceMediaStream::ICE_STREAM_GATHER_INIT:
+      return dom::RTCIceGathererState::New;
+    case NrIceMediaStream::ICE_STREAM_GATHER_STARTED:
+      return dom::RTCIceGathererState::Gathering;
+    case NrIceMediaStream::ICE_STREAM_GATHER_COMPLETE:
+      return dom::RTCIceGathererState::Complete;
   }
   MOZ_CRASH();
 }
 
 void MediaTransportHandlerSTS::OnGatheringStateChange(
-    NrIceCtx* aIceCtx, NrIceCtx::GatheringState aState) {
-  OnGatheringStateChange(toDomIceGatheringState(aState));
+    const std::string& aTransportId, NrIceMediaStream::GatheringState aState) {
+  OnGatheringStateChange(aTransportId, toDomIceGathererState(aState));
 }
 
-static mozilla::dom::RTCIceConnectionState toDomIceConnectionState(
+static mozilla::dom::RTCIceTransportState toDomIceTransportState(
     NrIceCtx::ConnectionState aState) {
   switch (aState) {
     case NrIceCtx::ICE_CTX_INIT:
-      return dom::RTCIceConnectionState::New;
+      return dom::RTCIceTransportState::New;
     case NrIceCtx::ICE_CTX_CHECKING:
-      return dom::RTCIceConnectionState::Checking;
+      return dom::RTCIceTransportState::Checking;
     case NrIceCtx::ICE_CTX_CONNECTED:
-      return dom::RTCIceConnectionState::Connected;
+      return dom::RTCIceTransportState::Connected;
     case NrIceCtx::ICE_CTX_COMPLETED:
-      return dom::RTCIceConnectionState::Completed;
+      return dom::RTCIceTransportState::Completed;
     case NrIceCtx::ICE_CTX_FAILED:
-      return dom::RTCIceConnectionState::Failed;
+      return dom::RTCIceTransportState::Failed;
     case NrIceCtx::ICE_CTX_DISCONNECTED:
-      return dom::RTCIceConnectionState::Disconnected;
+      return dom::RTCIceTransportState::Disconnected;
     case NrIceCtx::ICE_CTX_CLOSED:
-      return dom::RTCIceConnectionState::Closed;
+      return dom::RTCIceTransportState::Closed;
   }
   MOZ_CRASH();
 }
 
 void MediaTransportHandlerSTS::OnConnectionStateChange(
-    NrIceCtx* aIceCtx, NrIceCtx::ConnectionState aState) {
-  OnConnectionStateChange(toDomIceConnectionState(aState));
+    NrIceMediaStream* aIceStream, NrIceCtx::ConnectionState aState) {
+  OnConnectionStateChange(aIceStream->GetId(), toDomIceTransportState(aState));
 }
 
 // The stuff below here will eventually go into the MediaTransportChild class
diff --git a/dom/media/webrtc/jsapi/MediaTransportHandler.h b/dom/media/webrtc/jsapi/MediaTransportHandler.h
index a776cb6fd7..100eff019e 100644
--- a/dom/media/webrtc/jsapi/MediaTransportHandler.h
+++ b/dom/media/webrtc/jsapi/MediaTransportHandler.h
@@ -12,7 +12,8 @@
 #include "transport/dtlsidentity.h"    // For DtlsDigest
 #include "mozilla/dom/RTCPeerConnectionBinding.h"
 #include "mozilla/dom/RTCConfigurationBinding.h"
-#include "transport/nricectx.h"  // Need some enums
+#include "mozilla/dom/RTCIceTransportBinding.h"  // RTCIceTransportState
+#include "transport/nricectx.h"                  // Need some enums
 #include "common/CandidateInfo.h"
 #include "transport/nr_socket_proxy_config.h"
 #include "RTCStatsReport.h"
@@ -122,8 +123,10 @@ class MediaTransportHandler {
 
   sigslot::signal2<const std::string&, const CandidateInfo&> SignalCandidate;
   sigslot::signal2<const std::string&, bool> SignalAlpnNegotiated;
-  sigslot::signal1<dom::RTCIceGatheringState> SignalGatheringStateChange;
-  sigslot::signal1<dom::RTCIceConnectionState> SignalConnectionStateChange;
+  sigslot::signal2<const std::string&, dom::RTCIceGathererState>
+      SignalGatheringStateChange;
+  sigslot::signal2<const std::string&, dom::RTCIceTransportState>
+      SignalConnectionStateChange;
 
   sigslot::signal2<const std::string&, const MediaPacket&> SignalPacketReceived;
   sigslot::signal2<const std::string&, const MediaPacket&>
@@ -142,8 +145,10 @@ class MediaTransportHandler {
   void OnCandidate(const std::string& aTransportId,
                    const CandidateInfo& aCandidateInfo);
   void OnAlpnNegotiated(const std::string& aAlpn);
-  void OnGatheringStateChange(dom::RTCIceGatheringState aState);
-  void OnConnectionStateChange(dom::RTCIceConnectionState aState);
+  void OnGatheringStateChange(const std::string& aTransportId,
+                              dom::RTCIceGathererState aState);
+  void OnConnectionStateChange(const std::string& aTransportId,
+                               dom::RTCIceTransportState aState);
   void OnPacketReceived(const std::string& aTransportId,
                         const MediaPacket& aPacket);
   void OnEncryptedSending(const std::string& aTransportId,
diff --git a/dom/media/webrtc/jsapi/MediaTransportHandlerIPC.cpp b/dom/media/webrtc/jsapi/MediaTransportHandlerIPC.cpp
index 847e9fd3de..4d13ae0ac0 100644
--- a/dom/media/webrtc/jsapi/MediaTransportHandlerIPC.cpp
+++ b/dom/media/webrtc/jsapi/MediaTransportHandlerIPC.cpp
@@ -406,21 +406,21 @@ mozilla::ipc::IPCResult MediaTransportChild::RecvOnAlpnNegotiated(
 }
 
 mozilla::ipc::IPCResult MediaTransportChild::RecvOnGatheringStateChange(
-    const int& state) {
+    const string& transportId, const int& state) {
   MutexAutoLock lock(mMutex);
   if (mUser) {
-    mUser->OnGatheringStateChange(
-        static_cast<dom::RTCIceGatheringState>(state));
+    mUser->OnGatheringStateChange(transportId,
+                                  static_cast<dom::RTCIceGathererState>(state));
   }
   return ipc::IPCResult::Ok();
 }
 
 mozilla::ipc::IPCResult MediaTransportChild::RecvOnConnectionStateChange(
-    const int& state) {
+    const string& transportId, const int& state) {
   MutexAutoLock lock(mMutex);
   if (mUser) {
     mUser->OnConnectionStateChange(
-        static_cast<dom::RTCIceConnectionState>(state));
+        transportId, static_cast<dom::RTCIceTransportState>(state));
   }
   return ipc::IPCResult::Ok();
 }
diff --git a/dom/media/webrtc/jsapi/MediaTransportParent.cpp b/dom/media/webrtc/jsapi/MediaTransportParent.cpp
index 31d0b9f30f..4bbd75b41c 100644
--- a/dom/media/webrtc/jsapi/MediaTransportParent.cpp
+++ b/dom/media/webrtc/jsapi/MediaTransportParent.cpp
@@ -49,14 +49,16 @@ class MediaTransportParent::Impl : public sigslot::has_slots<> {
     NS_ENSURE_TRUE_VOID(mParent->SendOnAlpnNegotiated(aAlpn));
   }
 
-  void OnGatheringStateChange(dom::RTCIceGatheringState aState) {
-    NS_ENSURE_TRUE_VOID(
-        mParent->SendOnGatheringStateChange(static_cast<int>(aState)));
+  void OnGatheringStateChange(const std::string& aTransportId,
+                              dom::RTCIceGathererState aState) {
+    NS_ENSURE_TRUE_VOID(mParent->SendOnGatheringStateChange(
+        aTransportId, static_cast<int>(aState)));
   }
 
-  void OnConnectionStateChange(dom::RTCIceConnectionState aState) {
-    NS_ENSURE_TRUE_VOID(
-        mParent->SendOnConnectionStateChange(static_cast<int>(aState)));
+  void OnConnectionStateChange(const std::string& aTransportId,
+                               dom::RTCIceTransportState aState) {
+    NS_ENSURE_TRUE_VOID(mParent->SendOnConnectionStateChange(
+        aTransportId, static_cast<int>(aState)));
   }
 
   void OnPacketReceived(const std::string& aTransportId,
diff --git a/dom/media/webrtc/jsapi/PeerConnectionImpl.cpp b/dom/media/webrtc/jsapi/PeerConnectionImpl.cpp
index 985100153a..9afa7e5dd2 100644
--- a/dom/media/webrtc/jsapi/PeerConnectionImpl.cpp
+++ b/dom/media/webrtc/jsapi/PeerConnectionImpl.cpp
@@ -85,6 +85,7 @@
 #include "mozilla/dom/RTCCertificate.h"
 #include "mozilla/dom/RTCSctpTransportBinding.h"  // RTCSctpTransportState
 #include "mozilla/dom/RTCDtlsTransportBinding.h"  // RTCDtlsTransportState
+#include "mozilla/dom/RTCIceTransportBinding.h"   // RTCIceTransportState
 #include "mozilla/dom/RTCRtpReceiverBinding.h"
 #include "mozilla/dom/RTCRtpSenderBinding.h"
 #include "mozilla/dom/RTCStatsReportBinding.h"
@@ -249,19 +250,41 @@ void PeerConnectionAutoTimer::UnregisterConnection(bool aContainedAV) {
 
 bool PeerConnectionAutoTimer::IsStopped() { return mRefCnt == 0; }
 
+// There is not presently an implementation of these for nsTHashMap :(
+inline void ImplCycleCollectionUnlink(
+    PeerConnectionImpl::RTCDtlsTransportMap& aMap) {
+  for (auto& tableEntry : aMap) {
+    ImplCycleCollectionUnlink(*tableEntry.GetModifiableData());
+  }
+  aMap.Clear();
+}
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback,
+    PeerConnectionImpl::RTCDtlsTransportMap& aMap, const char* aName,
+    uint32_t aFlags = 0) {
+  for (auto& tableEntry : aMap) {
+    ImplCycleCollectionTraverse(aCallback, *tableEntry.GetModifiableData(),
+                                aName, aFlags);
+  }
+}
+
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(PeerConnectionImpl)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(PeerConnectionImpl)
   tmp->Close();
   tmp->BreakCycles();
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPCObserver, mWindow, mCertificate,
-                                  mSTSThread, mReceiveStreams, mOperations,
-                                  mSctpTransport, mKungFuDeathGrip)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(
+      mPCObserver, mWindow, mCertificate, mSTSThread, mReceiveStreams,
+      mOperations, mTransportIdToRTCDtlsTransport, mSctpTransport,
+      mLastStableSctpTransport, mLastStableSctpDtlsTransport, mKungFuDeathGrip)
   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(PeerConnectionImpl)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(
       mPCObserver, mWindow, mCertificate, mSTSThread, mReceiveStreams,
-      mOperations, mTransceivers, mSctpTransport, mKungFuDeathGrip)
+      mOperations, mTransceivers, mTransportIdToRTCDtlsTransport,
+      mSctpTransport, mLastStableSctpTransport, mLastStableSctpDtlsTransport,
+      mKungFuDeathGrip)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(PeerConnectionImpl)
@@ -849,6 +872,7 @@ nsresult PeerConnectionImpl::GetDatachannelParameters(
 
   if (!datachannelTransceiver ||
       !datachannelTransceiver->mTransport.mComponents ||
+      !datachannelTransceiver->mTransport.mDtls ||
       !datachannelTransceiver->mSendTrack.GetNegotiatedDetails()) {
     return NS_ERROR_FAILURE;
   }
@@ -1061,7 +1085,7 @@ bool PeerConnectionImpl::CreatedSender(const dom::RTCRtpSender& aSender) const {
   return aSender.IsMyPc(this);
 }
 
-nsresult PeerConnectionImpl::InitializeDataChannel() {
+nsresult PeerConnectionImpl::MaybeInitializeDataChannel() {
   PC_AUTO_ENTER_API_CALL(false);
   CSFLogDebug(LOGTAG, "%s", __FUNCTION__);
 
@@ -1440,6 +1464,16 @@ void PeerConnectionImpl::UpdateNegotiationNeeded() {
       }));
 }
 
+RefPtr<dom::RTCRtpTransceiver> PeerConnectionImpl::GetTransceiver(
+    const std::string& aTransceiverId) {
+  for (const auto& transceiver : mTransceivers) {
+    if (transceiver->GetJsepTransceiverId() == aTransceiverId) {
+      return transceiver;
+    }
+  }
+  return nullptr;
+}
+
 void PeerConnectionImpl::NotifyDataChannel(
     already_AddRefed<DataChannel> aChannel) {
   PC_AUTO_ENTER_API_CALL_NO_CHECK();
@@ -1637,7 +1671,6 @@ JsepSdpType ToJsepSdpType(dom::RTCSdpType aType) {
       return kJsepSdpAnswer;
     case dom::RTCSdpType::Rollback:
       return kJsepSdpRollback;
-    case dom::RTCSdpType::EndGuard_:;
   }
 
   MOZ_CRASH("Nonexistent dom::RTCSdpType");
@@ -1989,10 +2022,14 @@ nsresult PeerConnectionImpl::OnAlpnNegotiated(bool aPrivacyRequested) {
 
 void PeerConnectionImpl::OnDtlsStateChange(const std::string& aTransportId,
                                            TransportLayer::State aState) {
-  auto it = mTransportIdToRTCDtlsTransport.find(aTransportId);
-  if (it != mTransportIdToRTCDtlsTransport.end()) {
-    it->second->UpdateState(aState);
+  nsCString key(aTransportId.data(), aTransportId.size());
+  RefPtr<RTCDtlsTransport> dtlsTransport =
+      mTransportIdToRTCDtlsTransport.Get(key);
+  if (!dtlsTransport) {
+    return;
   }
+
+  dtlsTransport->UpdateState(aState);
   // Whenever the state of an RTCDtlsTransport changes or when the [[IsClosed]]
   // slot turns true, the user agent MUST update the connection state by
   // queueing a task that runs the following steps:
@@ -2024,9 +2061,9 @@ RTCPeerConnectionState PeerConnectionImpl::GetNewConnectionState() const {
   // Would use a bitset, but that requires lots of static_cast<size_t>
   // Oh well.
   std::set<RTCDtlsTransportState> statesFound;
-  for (const auto& [id, dtlsTransport] : mTransportIdToRTCDtlsTransport) {
-    Unused << id;
-    statesFound.insert(dtlsTransport->State());
+  std::set<RefPtr<RTCDtlsTransport>> transports(GetActiveTransports());
+  for (const auto& transport : transports) {
+    statesFound.insert(transport->State());
   }
 
   // failed 	The previous state doesn't apply, and either
@@ -2075,9 +2112,9 @@ RTCPeerConnectionState PeerConnectionImpl::GetNewConnectionState() const {
 bool PeerConnectionImpl::UpdateConnectionState() {
   auto newState = GetNewConnectionState();
   if (newState != mConnectionState) {
-    CSFLogDebug(LOGTAG, "%s: %d -> %d (%p)", __FUNCTION__,
-                static_cast<int>(mConnectionState), static_cast<int>(newState),
-                this);
+    CSFLogInfo(LOGTAG, "%s: %d -> %d (%p)", __FUNCTION__,
+               static_cast<int>(mConnectionState), static_cast<int>(newState),
+               this);
     mConnectionState = newState;
     if (mConnectionState != RTCPeerConnectionState::Closed) {
       return true;
@@ -2569,7 +2606,7 @@ PeerConnectionImpl::Close() {
     transceiver->Close();
   }
 
-  mTransportIdToRTCDtlsTransport.clear();
+  mTransportIdToRTCDtlsTransport.Clear();
 
   mQueuedIceCtxOperations.clear();
 
@@ -2964,18 +3001,25 @@ void PeerConnectionImpl::DoSetDescriptionSuccessPostProcessing(
           InvalidateLastReturnedParameters();
         }
 
+        if (aSdpType == dom::RTCSdpType::Offer &&
+            mSignalingState == RTCSignalingState::Stable) {
+          // If description is of type "offer" and
+          // connection.[[SignalingState]] is "stable" then for each
+          // transceiver in connection's set of transceivers, run the following
+          // steps:
+          SaveStateForRollback();
+        }
+
         // Section 4.4.1.5 Set the RTCSessionDescription:
         if (aSdpType == dom::RTCSdpType::Rollback) {
           // - step 4.5.10, type is rollback
-          RollbackRTCDtlsTransports();
+          RestoreStateForRollback();
         } else if (!(aRemote && aSdpType == dom::RTCSdpType::Offer)) {
           // - step 4.5.9 type is not rollback
           // - step 4.5.9.1 when remote is false
           // - step 4.5.9.2.13 when remote is true, type answer or pranswer
           // More simply: not rollback, and not for remote offers.
-          bool markAsStable = aSdpType == dom::RTCSdpType::Offer &&
-                              mSignalingState == RTCSignalingState::Stable;
-          UpdateRTCDtlsTransports(markAsStable);
+          UpdateRTCDtlsTransports();
         }
 
         // Did we just apply a local description?
@@ -2992,11 +3036,6 @@ void PeerConnectionImpl::DoSetDescriptionSuccessPostProcessing(
         }
 
         if (mJsepSession->GetState() == kJsepStateStable) {
-          if (aSdpType != dom::RTCSdpType::Rollback) {
-            // We need this initted for UpdateTransports
-            InitializeDataChannel();
-          }
-
           // If we're rolling back a local offer, we might need to remove some
           // transports, and stomp some MediaPipeline setup, but nothing further
           // needs to be done.
@@ -3071,6 +3110,10 @@ void PeerConnectionImpl::DoSetDescriptionSuccessPostProcessing(
         // Spec does not actually tell us to do this, but that is probably a
         // spec bug.
         // https://github.com/w3c/webrtc-pc/issues/2817
+        bool gatheringStateChanged = UpdateIceGatheringState();
+
+        bool iceConnectionStateChanged = UpdateIceConnectionState();
+
         bool connectionStateChanged = UpdateConnectionState();
 
         // This only gets populated for remote descriptions
@@ -3104,6 +3147,16 @@ void PeerConnectionImpl::DoSetDescriptionSuccessPostProcessing(
           pcObserver->OnStateChange(PCObserverStateType::SignalingState, jrv);
         }
 
+        if (gatheringStateChanged) {
+          pcObserver->OnStateChange(PCObserverStateType::IceGatheringState,
+                                    jrv);
+        }
+
+        if (iceConnectionStateChanged) {
+          pcObserver->OnStateChange(PCObserverStateType::IceConnectionState,
+                                    jrv);
+        }
+
         if (connectionStateChanged) {
           pcObserver->OnStateChange(PCObserverStateType::ConnectionState, jrv);
         }
@@ -3290,61 +3343,162 @@ void PeerConnectionImpl::SendLocalIceCandidateToContent(
 }
 
 void PeerConnectionImpl::IceConnectionStateChange(
-    dom::RTCIceConnectionState domState) {
+    const std::string& aTransportId, dom::RTCIceTransportState domState) {
+  // If connection.[[IsClosed]] is true, abort these steps.
   PC_AUTO_ENTER_API_CALL_VOID_RETURN(false);
 
-  CSFLogDebug(LOGTAG, "%s: %d -> %d", __FUNCTION__,
-              static_cast<int>(mIceConnectionState),
-              static_cast<int>(domState));
+  CSFLogDebug(LOGTAG, "IceConnectionStateChange: %s %d (%p)",
+              aTransportId.c_str(), static_cast<int>(domState), this);
 
-  if (domState == mIceConnectionState) {
-    // no work to be done since the states are the same.
-    // this can happen during ICE rollback situations.
+  // Let transport be the RTCIceTransport whose state is changing.
+  nsCString key(aTransportId.data(), aTransportId.size());
+  RefPtr<RTCDtlsTransport> dtlsTransport =
+      mTransportIdToRTCDtlsTransport.Get(key);
+  if (!dtlsTransport) {
     return;
   }
+  RefPtr<RTCIceTransport> transport = dtlsTransport->IceTransport();
 
-  mIceConnectionState = domState;
+  if (domState == RTCIceTransportState::Closed) {
+    mTransportIdToRTCDtlsTransport.Remove(key);
+  }
 
-  // Would be nice if we had a means of converting one of these dom enums
-  // to a string that wasn't almost as much text as this switch statement...
-  switch (mIceConnectionState) {
-    case RTCIceConnectionState::New:
-      STAMP_TIMECARD(mTimeCard, "Ice state: new");
-      break;
-    case RTCIceConnectionState::Checking:
-      // For telemetry
-      mIceStartTime = TimeStamp::Now();
-      STAMP_TIMECARD(mTimeCard, "Ice state: checking");
-      break;
-    case RTCIceConnectionState::Connected:
-      STAMP_TIMECARD(mTimeCard, "Ice state: connected");
-      StartCallTelem();
-      break;
-    case RTCIceConnectionState::Completed:
-      STAMP_TIMECARD(mTimeCard, "Ice state: completed");
-      break;
-    case RTCIceConnectionState::Failed:
-      STAMP_TIMECARD(mTimeCard, "Ice state: failed");
-      break;
-    case RTCIceConnectionState::Disconnected:
-      STAMP_TIMECARD(mTimeCard, "Ice state: disconnected");
-      break;
-    case RTCIceConnectionState::Closed:
-      STAMP_TIMECARD(mTimeCard, "Ice state: closed");
-      break;
-    default:
-      MOZ_ASSERT_UNREACHABLE("Unexpected mIceConnectionState!");
+  // Let selectedCandidatePairChanged be false.
+  // TODO(bug 1307994)
+
+  // Let transportIceConnectionStateChanged be false.
+  bool transportIceConnectionStateChanged = false;
+
+  // Let connectionIceConnectionStateChanged be false.
+  bool connectionIceConnectionStateChanged = false;
+
+  // Let connectionStateChanged be false.
+  bool connectionStateChanged = false;
+
+  if (transport->State() == domState) {
+    return;
+  }
+
+  // If transport's RTCIceTransportState was changed, run the following steps:
+
+  // Set transport.[[IceTransportState]] to the new indicated
+  // RTCIceTransportState.
+  transport->SetState(domState);
+
+  // Set transportIceConnectionStateChanged to true.
+  transportIceConnectionStateChanged = true;
+
+  // Set connection.[[IceConnectionState]] to the value of deriving a new state
+  // value as described by the RTCIceConnectionState enum.
+  if (UpdateIceConnectionState()) {
+    // If connection.[[IceConnectionState]] changed in the previous step, set
+    // connectionIceConnectionStateChanged to true.
+    connectionIceConnectionStateChanged = true;
+  }
+
+  // Set connection.[[ConnectionState]] to the value of deriving a new state
+  // value as described by the RTCPeerConnectionState enum.
+  if (UpdateConnectionState()) {
+    // If connection.[[ConnectionState]] changed in the previous step, set
+    // connectionStateChanged to true.
+    connectionStateChanged = true;
+  }
+
+  // If selectedCandidatePairChanged is true, fire an event named
+  // selectedcandidatepairchange at transport.
+  // TODO(bug 1307994)
+
+  // If transportIceConnectionStateChanged is true, fire an event named
+  // statechange at transport.
+  if (transportIceConnectionStateChanged) {
+    transport->FireStateChangeEvent();
   }
 
-  bool connectionStateChanged = UpdateConnectionState();
   WrappableJSErrorResult rv;
   RefPtr<PeerConnectionObserver> pcObserver(mPCObserver);
-  pcObserver->OnStateChange(PCObserverStateType::IceConnectionState, rv);
+
+  // If connectionIceConnectionStateChanged is true, fire an event named
+  // iceconnectionstatechange at connection.
+  if (connectionIceConnectionStateChanged) {
+    pcObserver->OnStateChange(PCObserverStateType::IceConnectionState, rv);
+  }
+
+  // If connectionStateChanged is true, fire an event named
+  // connectionstatechange at connection.
   if (connectionStateChanged) {
     pcObserver->OnStateChange(PCObserverStateType::ConnectionState, rv);
   }
 }
 
+RTCIceConnectionState PeerConnectionImpl::GetNewIceConnectionState() const {
+  // closed 	The RTCPeerConnection object's [[IsClosed]] slot is true.
+  if (IsClosed()) {
+    return RTCIceConnectionState::Closed;
+  }
+
+  // Would use a bitset, but that requires lots of static_cast<size_t>
+  // Oh well.
+  std::set<RTCIceTransportState> statesFound;
+  std::set<RefPtr<RTCDtlsTransport>> transports(GetActiveTransports());
+  for (const auto& transport : transports) {
+    RefPtr<dom::RTCIceTransport> iceTransport = transport->IceTransport();
+    CSFLogWarn(LOGTAG, "GetNewIceConnectionState: %p %d", iceTransport.get(),
+               static_cast<int>(iceTransport->State()));
+    statesFound.insert(iceTransport->State());
+  }
+
+  // failed 	 None of the previous states apply and any RTCIceTransports are
+  // in the "failed" state.
+  if (statesFound.count(RTCIceTransportState::Failed)) {
+    return RTCIceConnectionState::Failed;
+  }
+
+  // disconnected 	 None of the previous states apply and any
+  // RTCIceTransports are in the "disconnected" state.
+  if (statesFound.count(RTCIceTransportState::Disconnected)) {
+    return RTCIceConnectionState::Disconnected;
+  }
+
+  // new 	 None of the previous states apply and all RTCIceTransports are
+  // in the "new" or "closed" state, or there are no transports.
+  if (!statesFound.count(RTCIceTransportState::Checking) &&
+      !statesFound.count(RTCIceTransportState::Completed) &&
+      !statesFound.count(RTCIceTransportState::Connected)) {
+    return RTCIceConnectionState::New;
+  }
+
+  // checking   None of the previous states apply and any RTCIceTransports are
+  // in the "new" or "checking" state.
+  if (statesFound.count(RTCIceTransportState::New) ||
+      statesFound.count(RTCIceTransportState::Checking)) {
+    return RTCIceConnectionState::Checking;
+  }
+
+  // completed  None of the previous states apply and all RTCIceTransports are
+  // in the "completed" or "closed" state.
+  if (!statesFound.count(RTCIceTransportState::Connected)) {
+    return RTCIceConnectionState::Completed;
+  }
+
+  // connected 	None of the previous states apply.
+  return RTCIceConnectionState::Connected;
+}
+
+bool PeerConnectionImpl::UpdateIceConnectionState() {
+  auto newState = GetNewIceConnectionState();
+  if (newState != mIceConnectionState) {
+    CSFLogInfo(LOGTAG, "%s: %d -> %d (%p)", __FUNCTION__,
+               static_cast<int>(mIceConnectionState),
+               static_cast<int>(newState), this);
+    mIceConnectionState = newState;
+    if (mIceConnectionState != RTCIceConnectionState::Closed) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void PeerConnectionImpl::OnCandidateFound(const std::string& aTransportId,
                                           const CandidateInfo& aCandidateInfo) {
   if (mStunAddrsRequest && !aCandidateInfo.mMDNSAddress.empty()) {
@@ -3378,18 +3532,82 @@ void PeerConnectionImpl::OnCandidateFound(const std::string& aTransportId,
 }
 
 void PeerConnectionImpl::IceGatheringStateChange(
-    dom::RTCIceGatheringState state) {
+    const std::string& aTransportId, dom::RTCIceGathererState state) {
+  // If connection.[[IsClosed]] is true, abort these steps.
   PC_AUTO_ENTER_API_CALL_VOID_RETURN(false);
 
-  CSFLogDebug(LOGTAG, "%s %d", __FUNCTION__, static_cast<int>(state));
-  if (mIceGatheringState == state) {
+  CSFLogWarn(LOGTAG, "IceGatheringStateChange: %s %d (%p)",
+             aTransportId.c_str(), static_cast<int>(state), this);
+
+  // Let transport be the RTCIceTransport for which candidate gathering
+  // began/finished.
+  nsCString key(aTransportId.data(), aTransportId.size());
+  RefPtr<RTCDtlsTransport> dtlsTransport =
+      mTransportIdToRTCDtlsTransport.Get(key);
+  if (!dtlsTransport) {
+    return;
+  }
+  RefPtr<RTCIceTransport> transport = dtlsTransport->IceTransport();
+
+  if (transport->GatheringState() == state) {
     return;
   }
 
-  mIceGatheringState = state;
+  // Set transport.[[IceGathererState]] to gathering.
+  // or
+  // Set transport.[[IceGathererState]] to complete.
+  transport->SetGatheringState(state);
+
+  // Set connection.[[IceGatheringState]] to the value of deriving a new state
+  // value as described by the RTCIceGatheringState enum.
+  //
+  // Let connectionIceGatheringStateChanged be true if
+  // connection.[[IceGatheringState]] changed in the previous step, otherwise
+  // false.
+  bool gatheringStateChanged = UpdateIceGatheringState();
+
+  // Do not read or modify state beyond this point.
+
+  // Fire an event named gatheringstatechange at transport.
+  transport->FireGatheringStateChangeEvent();
+
+  // If connectionIceGatheringStateChanged is true, fire an event named
+  // icegatheringstatechange at connection.
+  if (gatheringStateChanged) {
+    // NOTE: If we're in the "complete" case, our JS code will fire a null
+    // icecandidate event after firing the icegatheringstatechange event.
+    // Fire an event named icecandidate using the RTCPeerConnectionIceEvent
+    // interface with the candidate attribute set to null at connection.
+    JSErrorResult rv;
+    mPCObserver->OnStateChange(PCObserverStateType::IceGatheringState, rv);
+  }
+}
+
+bool PeerConnectionImpl::UpdateIceGatheringState() {
+  // If connection.[[IsClosed]] is true, abort these steps.
+  if (IsClosed()) {
+    return false;
+  }
+
+  // Let newState be the value of deriving a new state value as
+  // described by the RTCIceGatheringState enum.
+  auto newState = GetNewIceGatheringState();
+
+  // If connection.[[IceGatheringState]] is equal to newState, abort
+  // these steps.
+  if (newState == mIceGatheringState) {
+    return false;
+  }
+
+  CSFLogInfo(LOGTAG, "UpdateIceGatheringState: %d -> %d (%p)",
+             static_cast<int>(mIceGatheringState), static_cast<int>(newState),
+             this);
+  // Set connection.[[IceGatheringState]] to newState.
+  mIceGatheringState = newState;
 
-  // Would be nice if we had a means of converting one of these dom enums
-  // to a string that wasn't almost as much text as this switch statement...
+  // Would be nice if we had a means of converting one of these dom
+  // enums to a string that wasn't almost as much text as this switch
+  // statement...
   switch (mIceGatheringState) {
     case RTCIceGatheringState::New:
       STAMP_TIMECARD(mTimeCard, "Ice gathering state: new");
@@ -3404,8 +3622,42 @@ void PeerConnectionImpl::IceGatheringStateChange(
       MOZ_ASSERT_UNREACHABLE("Unexpected mIceGatheringState!");
   }
 
-  JSErrorResult rv;
-  mPCObserver->OnStateChange(PCObserverStateType::IceGatheringState, rv);
+  return true;
+}
+
+RTCIceGatheringState PeerConnectionImpl::GetNewIceGatheringState() const {
+  // new 	Any of the RTCIceTransports are in the "new" gathering state
+  // and none of the transports are in the "gathering" state, or there are no
+  // transports.
+
+  // NOTE! This derives the RTCIce**Gathering**State from the individual
+  // RTCIce**Gatherer**State of the transports. These are different enums.
+  // But they have exactly the same values, in the same order.
+  // ¯\_(ツ)_/¯
+  bool foundComplete = false;
+  std::set<RefPtr<RTCDtlsTransport>> transports(GetActiveTransports());
+  for (const auto& transport : transports) {
+    RefPtr<dom::RTCIceTransport> iceTransport = transport->IceTransport();
+    switch (iceTransport->GatheringState()) {
+      case RTCIceGathererState::New:
+        break;
+      case RTCIceGathererState::Gathering:
+        // gathering 	Any of the RTCIceTransports are in the "gathering"
+        // state.
+        return RTCIceGatheringState::Gathering;
+      case RTCIceGathererState::Complete:
+        foundComplete = true;
+        break;
+    }
+  }
+
+  if (!foundComplete) {
+    return RTCIceGatheringState::New;
+  }
+
+  // This could change depending on the outcome in
+  // https://github.com/w3c/webrtc-pc/issues/2914
+  return RTCIceGatheringState::Complete;
 }
 
 void PeerConnectionImpl::UpdateDefaultCandidate(
@@ -3878,11 +4130,8 @@ void PeerConnectionImpl::StunAddrsHandler::OnStunAddrsAvailable(
   pcw.impl()->mStunAddrs = addrs.Clone();
   pcw.impl()->mLocalAddrsRequestState = STUN_ADDR_REQUEST_COMPLETE;
   pcw.impl()->FlushIceCtxOperationQueueIfReady();
-  // If parent process returns 0 STUN addresses, change ICE connection
-  // state to failed.
-  if (!pcw.impl()->mStunAddrs.Length()) {
-    pcw.impl()->IceConnectionStateChange(dom::RTCIceConnectionState::Failed);
-  }
+  // If this fails, ICE cannot succeed, but we need to still go through the
+  // motions.
 }
 
 void PeerConnectionImpl::InitLocalAddrs() {
@@ -3952,109 +4201,120 @@ void PeerConnectionImpl::EnsureTransports(const JsepSession& aSession) {
   GatherIfReady();
 }
 
-void PeerConnectionImpl::UpdateRTCDtlsTransports(bool aMarkAsStable) {
+void PeerConnectionImpl::UpdateRTCDtlsTransports() {
+  // We use mDataConnection below, make sure it is initted if necessary
+  MaybeInitializeDataChannel();
+
+  // Make sure that the SCTP transport is unset if we do not see a DataChannel.
+  // We'll restore this if we do see a DataChannel.
+  RefPtr<dom::RTCSctpTransport> oldSctp = mSctpTransport.forget();
+
   mJsepSession->ForEachTransceiver(
-      [this, self = RefPtr<PeerConnectionImpl>(this)](
-          const JsepTransceiver& jsepTransceiver) {
+      [this, self = RefPtr<PeerConnectionImpl>(this),
+       oldSctp](const JsepTransceiver& jsepTransceiver) {
         std::string transportId = jsepTransceiver.mTransport.mTransportId;
-        if (transportId.empty()) {
-          return;
+        RefPtr<dom::RTCDtlsTransport> dtlsTransport;
+        if (!transportId.empty()) {
+          nsCString key(transportId.data(), transportId.size());
+          dtlsTransport = mTransportIdToRTCDtlsTransport.GetOrInsertNew(
+              key, GetParentObject());
         }
-        if (!mTransportIdToRTCDtlsTransport.count(transportId)) {
-          mTransportIdToRTCDtlsTransport.emplace(
-              transportId, new RTCDtlsTransport(GetParentObject()));
+
+        if (jsepTransceiver.GetMediaType() == SdpMediaSection::kApplication) {
+          // Spec says we only update the RTCSctpTransport when negotiation
+          // completes. This is probably a spec bug.
+          // https://github.com/w3c/webrtc-pc/issues/2898
+          if (!dtlsTransport || !mDataConnection) {
+            return;
+          }
+
+          // Why on earth does the spec use a floating point for this?
+          double maxMessageSize =
+              static_cast<double>(mDataConnection->GetMaxMessageSize());
+          Nullable<uint16_t> maxChannels;
+
+          if (!oldSctp) {
+            mSctpTransport = new RTCSctpTransport(
+                GetParentObject(), *dtlsTransport, maxMessageSize, maxChannels);
+          } else {
+            // Restore the SCTP transport we had before this function was called
+            oldSctp->SetTransport(*dtlsTransport);
+            oldSctp->SetMaxMessageSize(maxMessageSize);
+            oldSctp->SetMaxChannels(maxChannels);
+            mSctpTransport = oldSctp;
+          }
+        } else {
+          RefPtr<dom::RTCRtpTransceiver> domTransceiver =
+              GetTransceiver(jsepTransceiver.GetUuid());
+          if (domTransceiver) {
+            domTransceiver->SetDtlsTransport(dtlsTransport);
+          }
         }
       });
+}
 
-  for (auto& transceiver : mTransceivers) {
-    std::string transportId = transceiver->GetTransportId();
-    if (transportId.empty()) {
-      continue;
-    }
-    if (mTransportIdToRTCDtlsTransport.count(transportId)) {
-      transceiver->SetDtlsTransport(mTransportIdToRTCDtlsTransport[transportId],
-                                    aMarkAsStable);
-    }
+void PeerConnectionImpl::SaveStateForRollback() {
+  // This could change depending on the outcome in
+  // https://github.com/w3c/webrtc-pc/issues/2899
+  if (mSctpTransport) {
+    // We have to save both of these things, because the DTLS transport could
+    // change without the SCTP transport changing.
+    mLastStableSctpTransport = mSctpTransport;
+    mLastStableSctpDtlsTransport = mSctpTransport->Transport();
+  } else {
+    mLastStableSctpTransport = nullptr;
+    mLastStableSctpDtlsTransport = nullptr;
   }
 
-  // Spec says we only update the RTCSctpTransport when negotiation completes
+  for (auto& transceiver : mTransceivers) {
+    transceiver->SaveStateForRollback();
+  }
 }
 
-void PeerConnectionImpl::RollbackRTCDtlsTransports() {
+void PeerConnectionImpl::RestoreStateForRollback() {
   for (auto& transceiver : mTransceivers) {
     transceiver->RollbackToStableDtlsTransport();
   }
+
+  mSctpTransport = mLastStableSctpTransport;
+  if (mSctpTransport) {
+    mSctpTransport->SetTransport(*mLastStableSctpDtlsTransport);
+  }
 }
 
-void PeerConnectionImpl::RemoveRTCDtlsTransportsExcept(
-    const std::set<std::string>& aTransportIds) {
-  for (auto iter = mTransportIdToRTCDtlsTransport.begin();
-       iter != mTransportIdToRTCDtlsTransport.end();) {
-    if (!aTransportIds.count(iter->first)) {
-      iter = mTransportIdToRTCDtlsTransport.erase(iter);
-    } else {
-      ++iter;
+std::set<RefPtr<dom::RTCDtlsTransport>>
+PeerConnectionImpl::GetActiveTransports() const {
+  std::set<RefPtr<dom::RTCDtlsTransport>> result;
+  for (const auto& transceiver : mTransceivers) {
+    if (transceiver->GetDtlsTransport()) {
+      result.insert(transceiver->GetDtlsTransport());
     }
   }
+
+  if (mSctpTransport && mSctpTransport->Transport()) {
+    result.insert(mSctpTransport->Transport());
+  }
+  return result;
 }
 
 nsresult PeerConnectionImpl::UpdateTransports(const JsepSession& aSession,
                                               const bool forceIceTcp) {
   std::set<std::string> finalTransports;
-  Maybe<std::string> sctpTransport;
   mJsepSession->ForEachTransceiver(
       [&, this, self = RefPtr<PeerConnectionImpl>(this)](
           const JsepTransceiver& transceiver) {
-        if (transceiver.GetMediaType() == SdpMediaSection::kApplication &&
-            transceiver.HasTransport()) {
-          sctpTransport = Some(transceiver.mTransport.mTransportId);
-        }
-
         if (transceiver.HasOwnTransport()) {
           finalTransports.insert(transceiver.mTransport.mTransportId);
           UpdateTransport(transceiver, forceIceTcp);
         }
       });
 
-  // clean up the unused RTCDtlsTransports
-  RemoveRTCDtlsTransportsExcept(finalTransports);
-
   mTransportHandler->RemoveTransportsExcept(finalTransports);
 
   for (const auto& transceiverImpl : mTransceivers) {
     transceiverImpl->UpdateTransport();
   }
 
-  if (sctpTransport.isSome()) {
-    auto it = mTransportIdToRTCDtlsTransport.find(*sctpTransport);
-    if (it == mTransportIdToRTCDtlsTransport.end()) {
-      // What?
-      MOZ_ASSERT(false);
-      return NS_ERROR_FAILURE;
-    }
-    if (!mDataConnection) {
-      // What?
-      MOZ_ASSERT(false);
-      return NS_ERROR_FAILURE;
-    }
-    RefPtr<RTCDtlsTransport> dtlsTransport = it->second;
-    // Why on earth does the spec use a floating point for this?
-    double maxMessageSize =
-        static_cast<double>(mDataConnection->GetMaxMessageSize());
-    Nullable<uint16_t> maxChannels;
-
-    if (!mSctpTransport) {
-      mSctpTransport = new RTCSctpTransport(GetParentObject(), *dtlsTransport,
-                                            maxMessageSize, maxChannels);
-    } else {
-      mSctpTransport->SetTransport(*dtlsTransport);
-      mSctpTransport->SetMaxMessageSize(maxMessageSize);
-      mSctpTransport->SetMaxChannels(maxChannels);
-    }
-  } else {
-    mSctpTransport = nullptr;
-  }
-
   return NS_OK;
 }
 
@@ -4141,6 +4401,9 @@ nsresult PeerConnectionImpl::UpdateMediaPipelines() {
 
 void PeerConnectionImpl::StartIceChecks(const JsepSession& aSession) {
   MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mJsepSession->GetState() == kJsepStateStable);
+
+  auto transports = GetActiveTransports();
 
   if (!mCanRegisterMDNSHostnamesDirectly) {
     for (auto& pair : mMDNSHostnamesToRegister) {
@@ -4472,32 +4735,31 @@ std::string PeerConnectionImpl::GetTransportIdMatchingSendTrack(
 }
 
 void PeerConnectionImpl::SignalHandler::IceGatheringStateChange_s(
-    dom::RTCIceGatheringState aState) {
+    const std::string& aTransportId, dom::RTCIceGathererState aState) {
   ASSERT_ON_THREAD(mSTSThread);
-
   GetMainThreadSerialEventTarget()->Dispatch(
       NS_NewRunnableFunction(__func__,
-                             [handle = mHandle, aState] {
+                             [handle = mHandle, aTransportId, aState] {
                                PeerConnectionWrapper wrapper(handle);
                                if (wrapper.impl()) {
                                  wrapper.impl()->IceGatheringStateChange(
-                                     aState);
+                                     aTransportId, aState);
                                }
                              }),
       NS_DISPATCH_NORMAL);
 }
 
 void PeerConnectionImpl::SignalHandler::IceConnectionStateChange_s(
-    dom::RTCIceConnectionState aState) {
+    const std::string& aTransportId, dom::RTCIceTransportState aState) {
   ASSERT_ON_THREAD(mSTSThread);
 
   GetMainThreadSerialEventTarget()->Dispatch(
       NS_NewRunnableFunction(__func__,
-                             [handle = mHandle, aState] {
+                             [handle = mHandle, aTransportId, aState] {
                                PeerConnectionWrapper wrapper(handle);
                                if (wrapper.impl()) {
                                  wrapper.impl()->IceConnectionStateChange(
-                                     aState);
+                                     aTransportId, aState);
                                }
                              }),
       NS_DISPATCH_NORMAL);
diff --git a/dom/media/webrtc/jsapi/PeerConnectionImpl.h b/dom/media/webrtc/jsapi/PeerConnectionImpl.h
index 085658b206..d7b54ad721 100644
--- a/dom/media/webrtc/jsapi/PeerConnectionImpl.h
+++ b/dom/media/webrtc/jsapi/PeerConnectionImpl.h
@@ -16,6 +16,7 @@
 #include "nsPIDOMWindow.h"
 #include "nsIUUIDGenerator.h"
 #include "nsIThread.h"
+#include "nsTHashSet.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/Attributes.h"
 
@@ -217,8 +218,10 @@ class PeerConnectionImpl final
   virtual const std::string& GetName();
 
   // ICE events
-  void IceConnectionStateChange(dom::RTCIceConnectionState state);
-  void IceGatheringStateChange(dom::RTCIceGatheringState state);
+  void IceConnectionStateChange(const std::string& aTransportId,
+                                dom::RTCIceTransportState state);
+  void IceGatheringStateChange(const std::string& aTransportId,
+                               dom::RTCIceGathererState state);
   void OnCandidateFound(const std::string& aTransportId,
                         const CandidateInfo& aCandidateInfo);
   void UpdateDefaultCandidate(const std::string& defaultAddr,
@@ -411,7 +414,7 @@ class PeerConnectionImpl final
 
   void RecordEndOfCallTelemetry();
 
-  nsresult InitializeDataChannel();
+  nsresult MaybeInitializeDataChannel();
 
   NS_IMETHODIMP_TO_ERRORRESULT_RETREF(nsDOMDataChannel, CreateDataChannel,
                                       ErrorResult& rv, const nsAString& aLabel,
@@ -481,6 +484,9 @@ class PeerConnectionImpl final
     aTransceiversOut = mTransceivers.Clone();
   }
 
+  RefPtr<dom::RTCRtpTransceiver> GetTransceiver(
+      const std::string& aTransceiverId);
+
   // Gets the RTC Signaling State of the JSEP session
   dom::RTCSignalingState GetSignalingState() const;
 
@@ -499,6 +505,12 @@ class PeerConnectionImpl final
   dom::RTCPeerConnectionState GetNewConnectionState() const;
   // Returns whether we need to fire a state change event
   bool UpdateConnectionState();
+  dom::RTCIceConnectionState GetNewIceConnectionState() const;
+  // Returns whether we need to fire a state change event
+  bool UpdateIceConnectionState();
+  dom::RTCIceGatheringState GetNewIceGatheringState() const;
+  // Returns whether we need to fire a state change event
+  bool UpdateIceGatheringState();
 
   // initialize telemetry for when calls start
   void StartCallTelem();
@@ -585,6 +597,9 @@ class PeerConnectionImpl final
 
   void BreakCycles();
 
+  using RTCDtlsTransportMap =
+      nsTHashMap<nsCStringHashKey, RefPtr<dom::RTCDtlsTransport>>;
+
  private:
   virtual ~PeerConnectionImpl();
   PeerConnectionImpl(const PeerConnectionImpl& rhs);
@@ -805,10 +820,10 @@ class PeerConnectionImpl final
   // Ensure ICE transports exist that we might need when offer/answer concludes
   void EnsureTransports(const JsepSession& aSession);
 
-  void UpdateRTCDtlsTransports(bool aMarkAsStable);
-  void RollbackRTCDtlsTransports();
-  void RemoveRTCDtlsTransportsExcept(
-      const std::set<std::string>& aTransportIds);
+  void UpdateRTCDtlsTransports();
+  void SaveStateForRollback();
+  void RestoreStateForRollback();
+  std::set<RefPtr<dom::RTCDtlsTransport>> GetActiveTransports() const;
 
   // Activate ICE transports at the conclusion of offer/answer,
   // or when rollback occurs.
@@ -861,9 +876,12 @@ class PeerConnectionImpl final
   std::set<std::pair<std::string, std::string>> mLocalIceCredentialsToReplace;
 
   nsTArray<RefPtr<dom::RTCRtpTransceiver>> mTransceivers;
-  std::map<std::string, RefPtr<dom::RTCDtlsTransport>>
-      mTransportIdToRTCDtlsTransport;
+  RTCDtlsTransportMap mTransportIdToRTCDtlsTransport;
   RefPtr<dom::RTCSctpTransport> mSctpTransport;
+  // This is similar to [[LastStableStateSender/ReceiverTransport]], but for
+  // DataChannel.
+  RefPtr<dom::RTCSctpTransport> mLastStableSctpTransport;
+  RefPtr<dom::RTCDtlsTransport> mLastStableSctpDtlsTransport;
 
   // Used whenever we need to dispatch a runnable to STS to tweak something
   // on our ICE ctx, but are not ready to do so at the moment (eg; we are
@@ -924,8 +942,10 @@ class PeerConnectionImpl final
     void ConnectSignals();
 
     // ICE events
-    void IceGatheringStateChange_s(dom::RTCIceGatheringState aState);
-    void IceConnectionStateChange_s(dom::RTCIceConnectionState aState);
+    void IceGatheringStateChange_s(const std::string& aTransportId,
+                                   dom::RTCIceGathererState aState);
+    void IceConnectionStateChange_s(const std::string& aTransportId,
+                                    dom::RTCIceTransportState aState);
     void OnCandidateFound_s(const std::string& aTransportId,
                             const CandidateInfo& aCandidateInfo);
     void AlpnNegotiated_s(const std::string& aAlpn, bool aPrivacyRequested);
diff --git a/dom/media/webrtc/jsapi/RTCDtlsTransport.cpp b/dom/media/webrtc/jsapi/RTCDtlsTransport.cpp
index 243f06d2f1..83e0aeee82 100644
--- a/dom/media/webrtc/jsapi/RTCDtlsTransport.cpp
+++ b/dom/media/webrtc/jsapi/RTCDtlsTransport.cpp
@@ -9,7 +9,8 @@
 
 namespace mozilla::dom {
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED(RTCDtlsTransport, DOMEventTargetHelper)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(RTCDtlsTransport, DOMEventTargetHelper,
+                                   mIceTransport)
 
 NS_IMPL_ADDREF_INHERITED(RTCDtlsTransport, DOMEventTargetHelper)
 NS_IMPL_RELEASE_INHERITED(RTCDtlsTransport, DOMEventTargetHelper)
@@ -19,7 +20,9 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(RTCDtlsTransport)
 NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
 
 RTCDtlsTransport::RTCDtlsTransport(nsPIDOMWindowInner* aWindow)
-    : DOMEventTargetHelper(aWindow), mState(RTCDtlsTransportState::New) {}
+    : DOMEventTargetHelper(aWindow),
+      mState(RTCDtlsTransportState::New),
+      mIceTransport(new RTCIceTransport(aWindow)) {}
 
 JSObject* RTCDtlsTransport::WrapObject(JSContext* aCx,
                                        JS::Handle<JSObject*> aGivenProto) {
diff --git a/dom/media/webrtc/jsapi/RTCDtlsTransport.h b/dom/media/webrtc/jsapi/RTCDtlsTransport.h
index 3800502154..3e744b5112 100644
--- a/dom/media/webrtc/jsapi/RTCDtlsTransport.h
+++ b/dom/media/webrtc/jsapi/RTCDtlsTransport.h
@@ -6,6 +6,7 @@
 #define _RTCDtlsTransport_h_
 
 #include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/dom/RTCIceTransport.h"
 #include "mozilla/RefPtr.h"
 #include "js/RootingAPI.h"
 #include "transport/transportlayer.h"
@@ -30,6 +31,7 @@ class RTCDtlsTransport : public DOMEventTargetHelper {
                        JS::Handle<JSObject*> aGivenProto) override;
   IMPL_EVENT_HANDLER(statechange)
   RTCDtlsTransportState State() const { return mState; }
+  RefPtr<RTCIceTransport> IceTransport() { return mIceTransport; }
 
   void UpdateStateNoEvent(TransportLayer::State aState);
   void UpdateState(TransportLayer::State aState);
@@ -38,6 +40,7 @@ class RTCDtlsTransport : public DOMEventTargetHelper {
   virtual ~RTCDtlsTransport() = default;
 
   RTCDtlsTransportState mState;
+  RefPtr<RTCIceTransport> mIceTransport;
 };
 
 }  // namespace mozilla::dom
diff --git a/dom/media/webrtc/jsapi/RTCIceTransport.cpp b/dom/media/webrtc/jsapi/RTCIceTransport.cpp
new file mode 100644
index 0000000000..4c5e6eef4f
--- /dev/null
+++ b/dom/media/webrtc/jsapi/RTCIceTransport.cpp
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "RTCIceTransport.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/EventBinding.h"
+#include "mozilla/dom/RTCIceTransportBinding.h"
+
+namespace mozilla::dom {
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(RTCIceTransport, DOMEventTargetHelper)
+
+NS_IMPL_ADDREF_INHERITED(RTCIceTransport, DOMEventTargetHelper)
+NS_IMPL_RELEASE_INHERITED(RTCIceTransport, DOMEventTargetHelper)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(RTCIceTransport)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
+
+RTCIceTransport::RTCIceTransport(nsPIDOMWindowInner* aWindow)
+    : DOMEventTargetHelper(aWindow),
+      mState(RTCIceTransportState::New),
+      mGatheringState(RTCIceGathererState::New) {}
+
+JSObject* RTCIceTransport::WrapObject(JSContext* aCx,
+                                      JS::Handle<JSObject*> aGivenProto) {
+  return RTCIceTransport_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void RTCIceTransport::SetState(RTCIceTransportState aState) { mState = aState; }
+
+void RTCIceTransport::SetGatheringState(RTCIceGathererState aState) {
+  mGatheringState = aState;
+}
+
+void RTCIceTransport::FireStateChangeEvent() {
+  EventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+
+  RefPtr<Event> event = Event::Constructor(this, u"statechange"_ns, init);
+
+  DispatchTrustedEvent(event);
+}
+
+void RTCIceTransport::FireGatheringStateChangeEvent() {
+  EventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+
+  RefPtr<Event> event =
+      Event::Constructor(this, u"gatheringstatechange"_ns, init);
+
+  DispatchTrustedEvent(event);
+}
+
+}  // namespace mozilla::dom
diff --git a/dom/media/webrtc/jsapi/RTCIceTransport.h b/dom/media/webrtc/jsapi/RTCIceTransport.h
new file mode 100644
index 0000000000..931aa66bac
--- /dev/null
+++ b/dom/media/webrtc/jsapi/RTCIceTransport.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_DOM_MEDIA_WEBRTC_JSAPI_RTCICETRANSPORT_H_
+#define MOZILLA_DOM_MEDIA_WEBRTC_JSAPI_RTCICETRANSPORT_H_
+
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/RefPtr.h"
+#include "js/RootingAPI.h"
+#include "transport/transportlayer.h"
+
+class nsPIDOMWindowInner;
+
+namespace mozilla::dom {
+
+enum class RTCIceTransportState : uint8_t;
+enum class RTCIceGathererState : uint8_t;
+
+class RTCIceTransport : public DOMEventTargetHelper {
+ public:
+  explicit RTCIceTransport(nsPIDOMWindowInner* aWindow);
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(RTCIceTransport,
+                                           DOMEventTargetHelper)
+
+  // webidl
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+  IMPL_EVENT_HANDLER(statechange)
+  IMPL_EVENT_HANDLER(gatheringstatechange)
+  RTCIceTransportState State() const { return mState; }
+  RTCIceGathererState GatheringState() const { return mGatheringState; }
+
+  void SetState(RTCIceTransportState aState);
+  void SetGatheringState(RTCIceGathererState aState);
+
+  void FireStateChangeEvent();
+  void FireGatheringStateChangeEvent();
+
+ private:
+  virtual ~RTCIceTransport() = default;
+
+  RTCIceTransportState mState;
+  RTCIceGathererState mGatheringState;
+};
+
+}  // namespace mozilla::dom
+#endif  // MOZILLA_DOM_MEDIA_WEBRTC_JSAPI_RTCICETRANSPORT_H_
diff --git a/dom/media/webrtc/jsapi/RTCRtpReceiver.cpp b/dom/media/webrtc/jsapi/RTCRtpReceiver.cpp
index efe83fb782..96db9fc312 100644
--- a/dom/media/webrtc/jsapi/RTCRtpReceiver.cpp
+++ b/dom/media/webrtc/jsapi/RTCRtpReceiver.cpp
@@ -709,9 +709,9 @@ void RTCRtpReceiver::UpdateTransport() {
     // Add unique payload types as a last-ditch fallback
     auto uniquePts = GetJsepTransceiver()
                          .mRecvTrack.GetNegotiatedDetails()
-                         ->GetUniquePayloadTypes();
+                         ->GetUniqueReceivePayloadTypes();
     for (unsigned char& uniquePt : uniquePts) {
-      filter->AddUniquePT(uniquePt);
+      filter->AddUniqueReceivePT(uniquePt);
     }
   }
 
diff --git a/dom/media/webrtc/jsapi/RTCRtpSender.cpp b/dom/media/webrtc/jsapi/RTCRtpSender.cpp
index 4ba0491521..da198c62e4 100644
--- a/dom/media/webrtc/jsapi/RTCRtpSender.cpp
+++ b/dom/media/webrtc/jsapi/RTCRtpSender.cpp
@@ -1502,7 +1502,6 @@ Maybe<RTCRtpSender::VideoConfig> RTCRtpSender::GetNewVideoConfig() {
 
       case dom::MediaSourceEnum::Microphone:
       case dom::MediaSourceEnum::AudioCapture:
-      case dom::MediaSourceEnum::EndGuard_:
         MOZ_ASSERT(false);
         break;
     }
diff --git a/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp b/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp
index b219619f87..6b7b456e46 100644
--- a/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp
+++ b/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp
@@ -239,7 +239,6 @@ SdpDirectionAttribute::Direction ToSdpDirection(
     case dom::RTCRtpTransceiverDirection::Inactive:
     case dom::RTCRtpTransceiverDirection::Stopped:
       return SdpDirectionAttribute::Direction::kInactive;
-    case dom::RTCRtpTransceiverDirection::EndGuard_:;
   }
   MOZ_CRASH("Invalid transceiver direction!");
 }
@@ -279,12 +278,13 @@ void RTCRtpTransceiver::Init(const RTCRtpTransceiverInit& aInit,
   mDirection = aInit.mDirection;
 }
 
-void RTCRtpTransceiver::SetDtlsTransport(dom::RTCDtlsTransport* aDtlsTransport,
-                                         bool aStable) {
+void RTCRtpTransceiver::SetDtlsTransport(
+    dom::RTCDtlsTransport* aDtlsTransport) {
   mDtlsTransport = aDtlsTransport;
-  if (aStable) {
-    mLastStableDtlsTransport = mDtlsTransport;
-  }
+}
+
+void RTCRtpTransceiver::SaveStateForRollback() {
+  mLastStableDtlsTransport = mDtlsTransport;
 }
 
 void RTCRtpTransceiver::RollbackToStableDtlsTransport() {
@@ -366,12 +366,17 @@ void RTCRtpTransceiver::InitConduitControl() {
 }
 
 void RTCRtpTransceiver::Close() {
-  // Called via PCImpl::Close -> PCImpl::CloseInt -> PCImpl::ShutdownMedia ->
-  // PCMedia::SelfDestruct.  Satisfies step 7 of
+  // Called via PCImpl::Close
+  // Satisfies steps 7 and 9 of
   // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-close
+  // No events are fired for this.
   mShutdown = true;
   if (mDtlsTransport) {
     mDtlsTransport->UpdateStateNoEvent(TransportLayer::TS_CLOSED);
+    // Might not be set if we're cycle-collecting
+    if (mDtlsTransport->IceTransport()) {
+      mDtlsTransport->IceTransport()->SetState(RTCIceTransportState::Closed);
+    }
   }
   StopImpl();
 }
@@ -401,9 +406,9 @@ void RTCRtpTransceiver::Unlink() {
 // TODO: Only called from one place in PeerConnectionImpl, synchronously, when
 // the JSEP engine has successfully completed an offer/answer exchange. This is
 // a bit squirrely, since identity validation happens asynchronously in
-// PeerConnection.jsm. This probably needs to happen once all the "in parallel"
-// steps have succeeded, but before we queue the task for JS observable state
-// updates.
+// PeerConnection.sys.mjs. This probably needs to happen once all the "in
+// parallel" steps have succeeded, but before we queue the task for JS
+// observable state updates.
 nsresult RTCRtpTransceiver::UpdateTransport() {
   if (!mHasTransport) {
     return NS_OK;
@@ -439,9 +444,9 @@ void RTCRtpTransceiver::ResetSync() { mSyncGroup = std::string(); }
 // TODO: Only called from one place in PeerConnectionImpl, synchronously, when
 // the JSEP engine has successfully completed an offer/answer exchange. This is
 // a bit squirrely, since identity validation happens asynchronously in
-// PeerConnection.jsm. This probably needs to happen once all the "in parallel"
-// steps have succeeded, but before we queue the task for JS observable state
-// updates.
+// PeerConnection.sys.mjs. This probably needs to happen once all the "in
+// parallel" steps have succeeded, but before we queue the task for JS
+// observable state updates.
 nsresult RTCRtpTransceiver::SyncWithMatchingVideoConduits(
     nsTArray<RefPtr<RTCRtpTransceiver>>& transceivers) {
   if (mStopped) {
diff --git a/dom/media/webrtc/jsapi/RTCRtpTransceiver.h b/dom/media/webrtc/jsapi/RTCRtpTransceiver.h
index afa6142d35..4fa7ef157c 100644
--- a/dom/media/webrtc/jsapi/RTCRtpTransceiver.h
+++ b/dom/media/webrtc/jsapi/RTCRtpTransceiver.h
@@ -119,7 +119,8 @@ class RTCRtpTransceiver : public nsISupports, public nsWrapperCache {
   void SyncFromJsep(const JsepSession& aSession);
   std::string GetMidAscii() const;
 
-  void SetDtlsTransport(RTCDtlsTransport* aDtlsTransport, bool aStable);
+  void SetDtlsTransport(RTCDtlsTransport* aDtlsTransport);
+  void SaveStateForRollback();
   void RollbackToStableDtlsTransport();
 
   std::string GetTransportId() const {
diff --git a/dom/media/webrtc/jsapi/moz.build b/dom/media/webrtc/jsapi/moz.build
index 78a6241cd6..05920fc151 100644
--- a/dom/media/webrtc/jsapi/moz.build
+++ b/dom/media/webrtc/jsapi/moz.build
@@ -31,6 +31,7 @@ UNIFIED_SOURCES += [
     "RTCEncodedAudioFrame.cpp",
     "RTCEncodedFrameBase.cpp",
     "RTCEncodedVideoFrame.cpp",
+    "RTCIceTransport.cpp",
     "RTCRtpReceiver.cpp",
     "RTCRtpScriptTransform.cpp",
     "RTCRtpScriptTransformer.cpp",
@@ -50,6 +51,7 @@ EXPORTS.mozilla.dom += [
     "RTCEncodedAudioFrame.h",
     "RTCEncodedFrameBase.h",
     "RTCEncodedVideoFrame.h",
+    "RTCIceTransport.h",
     "RTCRtpReceiver.h",
     "RTCRtpScriptTransform.h",
     "RTCRtpScriptTransformer.h",