From 6e23a692fe7cba6dd4a4c0d1863ff7245a9de9a7 Mon Sep 17 00:00:00 2001
From: Pedro Rodriguez <lodoyun@gmail.com>
Date: Thu, 7 Feb 2019 12:19:40 +0100
Subject: [PATCH] Fix negotiation problems in Single PeerConnection (#1355)

---
 .../erizoClient/src/webrtc-stacks/BaseStack.js      | 13 +++++++++++--
 erizo_controller/erizoJS/models/Connection.js       |  9 +++++++--
 .../erizoJS/models/SessionDescription.js            |  7 +++++++
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/erizo_controller/erizoClient/src/webrtc-stacks/BaseStack.js b/erizo_controller/erizoClient/src/webrtc-stacks/BaseStack.js
index 487a0ca93d..724dfe031d 100644
--- a/erizo_controller/erizoClient/src/webrtc-stacks/BaseStack.js
+++ b/erizo_controller/erizoClient/src/webrtc-stacks/BaseStack.js
@@ -94,7 +94,7 @@ const BaseStack = (specInput) => {
 
   const checkOfferQueue = () => {
     if (!isNegotiating && offerQueue.length > 0) {
-      const args = offerQueue.pop();
+      const args = offerQueue.shift();
       if (args[0] === 'local') {
         that.createOffer(args[1], args[2], args[3]);
       } else {
@@ -145,8 +145,16 @@ const BaseStack = (specInput) => {
       offerQueue.push(['remote', message]);
       return;
     }
-    isNegotiating = true;
     remoteSdp = SemanticSdp.SDPInfo.processString(msg.sdp);
+
+    const sessionVersion = remoteSdp && remoteSdp.origin && remoteSdp.origin.sessionVersion;
+    if (latestSessionVersion >= sessionVersion) {
+      Logger.warning(`message: processOffer discarding old sdp sessionVersion: ${sessionVersion}, latestSessionVersion: ${latestSessionVersion}`);
+      return;
+    }
+    isNegotiating = true;
+    latestSessionVersion = sessionVersion;
+
     SdpHelpers.setMaxBW(remoteSdp, specBase);
     msg.sdp = remoteSdp.toString();
     that.remoteSdp = remoteSdp;
@@ -164,6 +172,7 @@ const BaseStack = (specInput) => {
     remoteSdp = SemanticSdp.SDPInfo.processString(msg.sdp);
     const sessionVersion = remoteSdp && remoteSdp.origin && remoteSdp.origin.sessionVersion;
     if (latestSessionVersion >= sessionVersion) {
+      Logger.warning(`processAnswer discarding old sdp, sessionVersion: ${sessionVersion}, latestSessionVersion: ${latestSessionVersion}`);
       return;
     }
     Logger.info('Set remote and local description');
diff --git a/erizo_controller/erizoJS/models/Connection.js b/erizo_controller/erizoJS/models/Connection.js
index d9cd2a7b40..dc3948bd38 100644
--- a/erizo_controller/erizoJS/models/Connection.js
+++ b/erizo_controller/erizoJS/models/Connection.js
@@ -124,12 +124,17 @@ class Connection extends events.EventEmitter {
     if (!this.wrtc.localDescription) {
       return;
     }
+    this.wrtc.localDescription = new SessionDescription(this.wrtc.getLocalDescription());
     const sdp = this.wrtc.localDescription.getSdp(this.sessionVersion);
-    this.sessionVersion += 1;
     const stream = sdp.getStream(label);
     if (stream && removeStream) {
-      sdp.removeStream(stream);
+      log.info(`resendLastAnswer: StreamId ${streamId} is stream and removeStream, label ${label}, sessionVersion ${this.sessionVersion}`);
+      setTimeout(() => {
+        this._resendLastAnswer(evt, streamId, label, forceOffer, removeStream);
+      }, 50);
+      return;
     }
+    this.sessionVersion += 1;
     let message = sdp.toString();
     message = message.replace(this.options.privateRegexp, this.options.publicIP);
 
diff --git a/erizo_controller/erizoJS/models/SessionDescription.js b/erizo_controller/erizoJS/models/SessionDescription.js
index f052181160..1802f90392 100644
--- a/erizo_controller/erizoJS/models/SessionDescription.js
+++ b/erizo_controller/erizoJS/models/SessionDescription.js
@@ -191,6 +191,13 @@ class SessionDescription {
 
   getSdp(sessionVersion = 0) {
     if (this.sdp) {
+      this.sdp.setOrigin({
+        username: '-',
+        sessionId: 0,
+        sessionVersion,
+        netType: 'IN',
+        ipVer: 4,
+        address: '127.0.0.1' });
       return this.sdp;
     }
     const info = this.connectionDescription;