Adding PortAllocator option to support cases where sockets can't be bound.

webrtc/p2p/client/basicportallocator.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 537 matching lines @@
   // If the adapter enumeration is disabled, we'll just bind to any address
   // instead of specific NIC. This is to ensure the same routing for http
   // traffic by OS is also used here to avoid any local or public IP leakage
   // during stun process.
   if (flags() & PORTALLOCATOR_DISABLE_ADAPTER_ENUMERATION) {
     network_manager->GetAnyAddressNetworks(&networks);
   } else {
     network_manager->GetNetworks(&networks);
     // If network enumeration fails, use the ANY address as a fallback, so we
     // can at least try gathering candidates using the default route chosen by
-    // the OS.
-    if (networks.empty()) {
+    // the OS. Or, if the PORTALLOCATOR_ENABLE_ANY_ADDRESS_PORTS flag is
+    // set, we'll use ANY address candidates either way.
+    if (networks.empty() || flags() & PORTALLOCATOR_ENABLE_ANY_ADDRESS_PORTS) {
       network_manager->GetAnyAddressNetworks(&networks);
     }
   }
   networks.erase(std::remove_if(networks.begin(), networks.end(),
                                 [this](rtc::Network* network) {
                                   return allocator_->network_ignore_mask() &
                                          network->type();
                                 }),
                  networks.end());
 
@@ skipping 957 matching lines @@
   ServerAddresses servers;
   for (size_t i = 0; i < relays.size(); ++i) {
     if (relays[i].type == turn_type && SupportsProtocol(relays[i], type)) {
       servers.insert(relays[i].ports.front().address);
     }
   }
   return servers;
 }
 
 }  // namespace cricket