Fixing off-by-one error with max SCTP id.

webrtc/api/datachannel.cc

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 13 matching lines @@
 static size_t kMaxQueuedSendDataBytes = 16 * 1024 * 1024;
 
 enum {
   MSG_CHANNELREADY,
 };
 
 bool SctpSidAllocator::AllocateSid(rtc::SSLRole role, int* sid) {
   int potential_sid = (role == rtc::SSL_CLIENT) ? 0 : 1;
   while (!IsSidAvailable(potential_sid)) {
     potential_sid += 2;
-    if (potential_sid > static_cast<int>(cricket::kMaxSctpSid)) {
+    if (potential_sid >= static_cast<int>(cricket::kMaxSctpStreams)) {

[pthatcher1, 2016/08/22 23:09:30]

I liked the way it read before: "if sid > maxSid { return false; }".  

[Taylor Brandstetter, 2016/08/23 00:53:14]

Done.

       return false;
     }
   }
 
   *sid = potential_sid;
   used_sids_.insert(potential_sid);
   return true;
 }
 
 bool SctpSidAllocator::ReserveSid(int sid) {
   if (!IsSidAvailable(sid)) {
     return false;
   }
   used_sids_.insert(sid);
   return true;
 }
 
 void SctpSidAllocator::ReleaseSid(int sid) {
   auto it = used_sids_.find(sid);
   if (it != used_sids_.end()) {
     used_sids_.erase(it);
   }
 }
 
 bool SctpSidAllocator::IsSidAvailable(int sid) const {
-  if (sid < 0 || sid > static_cast<int>(cricket::kMaxSctpSid)) {
+  if (sid < 0 || sid >= static_cast<int>(cricket::kMaxSctpStreams)) {
     return false;
   }
   return used_sids_.find(sid) == used_sids_.end();
 }
 
 DataChannel::PacketQueue::PacketQueue() : byte_count_(0) {}
 
 DataChannel::PacketQueue::~PacketQueue() {
   Clear();
 }
@@ skipping 560 matching lines @@
     QueueControlMessage(buffer);
   } else {
     LOG(LS_ERROR) << "Closing the DataChannel due to a failure to send"
                   << " the CONTROL message, send_result = " << send_result;
     Close();
   }
   return retval;
 }
 
 }  // namespace webrtc