fix: harden datachannel close and state repair

Author: mertushka

lib/index.js

@@ -1365,13 +1365,16 @@ class RTCDataChannel extends SimpleEventTarget {
       this._pc._pairDataChannelById(this, this._effectiveId());
     }
     const pairedChannel = this._pairedChannel;
-    const synthesizePairedClose =
-      pairedChannel && this._bufferedAmount === 0 && !this._hasPendingSends();
     if (!this._nativeCloseScheduled) {
       this._nativeCloseScheduled = true;
       const shouldDrainBeforeClose = this._bufferedAmount > 0 || this._hasPendingSends();
       const closeNative = () => {
         const close = () => {
+          const synthesizePairedClose =
+            pairedChannel &&
+            pairedChannel.readyState !== "closed" &&
+            (pairedChannel._syntheticIncoming ||
+              (this._bufferedAmount === 0 && !this._hasPendingSends()));
           this._native.close();
           if (synthesizePairedClose) {
             setTimeout(() => pairedChannel._handleRemoteChannelClose(), 0);
@@ -1877,6 +1880,7 @@ class RTCPeerConnection extends SimpleEventTarget {
     this._sctpTransportUpdateScheduled = false;
     this._sctpConnectPollScheduled = false;
     this._sctpConnectPollDeadline = 0;
+    this._connectedStateRepairScheduled = false;
     this._dataChannelOpenRepairScheduled = false;
     this._dataChannelOpenRepairDeadline = 0;
     this._dataChannelAnnouncementRepairScheduled = false;
@@ -2741,13 +2745,66 @@ class RTCPeerConnection extends SimpleEventTarget {
     this._sctpTransport._setState(closed ? "closed" : connected ? "connected" : "connecting");
     if (connected || closed) this._sctpConnectPollDeadline = 0;
     if (connected) {
+      this._scheduleConnectedStateRepair();
       this._scheduleDataChannelOpenRepair();
       this._scheduleDataChannelAnnouncementRepair();
       this._pairedPeer?._scheduleDataChannelAnnouncementRepair();
     }
     this._scheduleSctpConnectPollIfNeeded();
   }
 
+  _shouldRepairConnectedState() {
+    return Boolean(
+      !this._closed &&
+        this._sctpTransport?.state === "connected" &&
+        this._sameProcessIceCandidateExchange &&
+        this._explicitIceCandidateExchange &&
+        this._hasNegotiatedDataTransport() &&
+        this._pairedPeer?._hasNegotiatedDataTransport() &&
+        this._operationsPending === 0 &&
+        this._pairedPeer._operationsPending === 0 &&
+        this._connectionState !== "failed" &&
+        this._connectionState !== "disconnected" &&
+        this._iceConnectionState !== "failed" &&
+        this._iceConnectionState !== "disconnected" &&
+        (this._connectionState !== "connected" ||
+          !["connected", "completed"].includes(this._iceConnectionState)),
+    );
+  }
+
+  _scheduleConnectedStateRepair() {
+    if (this._connectedStateRepairScheduled || !this._shouldRepairConnectedState()) return;
+    this._connectedStateRepairScheduled = true;
+    setTimeout(() => {
+      this._connectedStateRepairScheduled = false;
+      if (!this._shouldRepairConnectedState()) return;
+
+      if (this._iceConnectionState === "new") {
+        this._iceConnectionState = "checking";
+        this.dispatchEvent(makeEvent("iceconnectionstatechange"));
+        this._iceTransport()?._handlePeerIceConnectionState("checking");
+      }
+      if (this._connectionState === "new") {
+        this._connectionState = "connecting";
+        this.dispatchEvent(makeEvent("connectionstatechange"));
+      }
+
+      setTimeout(() => {
+        if (!this._shouldRepairConnectedState()) return;
+        if (!["connected", "completed"].includes(this._iceConnectionState)) {
+          this._iceConnectionState = "connected";
+          this.dispatchEvent(makeEvent("iceconnectionstatechange"));
+          this._iceTransport()?._handlePeerIceConnectionState("connected");
+        }
+        if (this._connectionState !== "connected") {
+          this._connectionState = "connected";
+          this._updateSctpTransport();
+          this.dispatchEvent(makeEvent("connectionstatechange"));
+        }
+      }, 0);
+    }, 0);
+  }
+
   _hasNegotiatedDataTransport() {
     return (
       hasDataMediaSection(this._localDescription) && hasDataMediaSection(this._remoteDescription)
@@ -3493,7 +3550,11 @@ class RTCPeerConnection extends SimpleEventTarget {
   }
 
   _eventListenerAdded(type) {
-    if (type === "datachannel") this._scheduleDataChannelFlush();
+    if (type === "datachannel") {
+      this._scheduleDataChannelFlush();
+      this._scheduleDataChannelAnnouncementRepair();
+      this._pairedPeer?._scheduleDataChannelAnnouncementRepair();
+    }
   }
 
   _scheduleDataChannelFlush() {

src/native/addon.cc

@@ -13,6 +13,7 @@
 #include <sstream>
 #include <stdexcept>
 #include <string>
+#include <thread>
 #include <unordered_map>
 #include <utility>
 #include <vector>
@@ -357,8 +358,14 @@ struct ChannelBinding : public std::enable_shared_from_this<ChannelBinding> {
 
 	void Close() {
 		auto dc = dataChannel;
-		if (dc)
-			dc->close();
+		if (!dc)
+			return;
+		std::thread([dc = std::move(dc)]() {
+			try {
+				dc->close();
+			} catch (...) {
+			}
+		}).detach();
 	}
 
 	void Destroy() {