Don't crash if STUN error message is missing ERROR-CODE attribute.

webrtc/p2p/base/stun.cc

 /*
  *  Copyright 2004 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 97 matching lines @@
 
 const StunByteStringAttribute* StunMessage::GetByteString(int type) const {
   return static_cast<const StunByteStringAttribute*>(GetAttribute(type));
 }
 
 const StunErrorCodeAttribute* StunMessage::GetErrorCode() const {
   return static_cast<const StunErrorCodeAttribute*>(
       GetAttribute(STUN_ATTR_ERROR_CODE));
 }
 
+int StunMessage::GetErrorCodeValue() const {
+  const StunErrorCodeAttribute* error_attribute = GetErrorCode();
+  return error_attribute ? error_attribute->code() : STUN_ERROR_GLOBAL_FAILURE;
+}
+
 const StunUInt16ListAttribute* StunMessage::GetUnknownAttributes() const {
   return static_cast<const StunUInt16ListAttribute*>(
       GetAttribute(STUN_ATTR_UNKNOWN_ATTRIBUTES));
 }
 
 // Verifies a STUN message has a valid MESSAGE-INTEGRITY attribute, using the
 // procedure outlined in RFC 5389, section 15.4.
 bool StunMessage::ValidateMessageIntegrity(const char* data, size_t size,
                                            const std::string& password) {
   // Verifying the size of the message.
@@ skipping 790 matching lines @@
       digest, sizeof(digest));
   if (size == 0) {
     return false;
   }
 
   *hash = std::string(digest, size);
   return true;
 }
 
 }  // namespace cricket