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

webrtc/p2p/base/portallocator.h

 /*
  *  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 59 matching lines @@
   // Wi-Fi network. If a network type is "unknown", it has a cost lower than
   // cellular but higher than Wi-Fi/Ethernet. So if an unknown network exists,
   // cellular networks will not be used to gather candidates and if a Wi-Fi
   // network is present, "unknown" networks will not be usd to gather
   // candidates. Doing so ensures that even if a cellular network type was not
   // detected initially, it would not be used if a Wi-Fi network is present.
   PORTALLOCATOR_DISABLE_COSTLY_NETWORKS = 0x2000,
 
   // When specified, do not collect IPv6 ICE candidates on Wi-Fi.
   PORTALLOCATOR_ENABLE_IPV6_ON_WIFI = 0x4000,
+
+  // When this flag is set, ports will be created not bound to any specific

[pthatcher1, 2017/06/13 19:52:50]

"created not bound" => "created but not bound"

[Taylor Brandstetter, 2017/06/13 22:11:18]

Revised comment.

+  // network interface, in addition to normal ports. Without this flag, these
+  // ports would only be used when network enumeration fails or is disabled.
+  // But under certain conditions, these ports may succeed where others fail,
+  // so they may allow the application to work in a wider variety of
+  // environments, at the expense of having to allocate additional candidates.
+  PORTALLOCATOR_ENABLE_ANY_ADDRESS_PORTS = 0x8000,
 };
 
 // Defines various reasons that have caused ICE regathering.
 enum class IceRegatheringReason { NETWORK_CHANGE, NETWORK_FAILURE, MAX_VALUE };
 
 const uint32_t kDefaultPortAllocatorFlags = 0;
 
 const uint32_t kDefaultStepDelay = 1000;  // 1 sec step delay.
 // As per RFC 5245 Appendix B.1, STUN transactions need to be paced at certain
 // internal. Less than 20ms is not acceptable. We choose 50ms as our default.
@@ skipping 372 matching lines @@
   std::deque<std::unique_ptr<PortAllocatorSession>> pooled_sessions_;
   bool candidate_pool_frozen_ = false;
   bool prune_turn_ports_ = false;
 
   webrtc::MetricsObserverInterface* metrics_observer_ = nullptr;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_PORTALLOCATOR_H_