Add a flag to filter out high-cost networks.

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 43 matching lines @@
   // interface as seen by regular http traffic and the HOST candidate associated
   // with the default local interface.
   PORTALLOCATOR_DISABLE_ADAPTER_ENUMERATION = 0x400,
   // When specified along with PORTALLOCATOR_DISABLE_ADAPTER_ENUMERATION, the
   // default local candidate mentioned above will not be allocated. Only the
   // STUN candidate will be.
   PORTALLOCATOR_DISABLE_DEFAULT_LOCAL_CANDIDATE = 0x800,
   // Disallow use of UDP when connecting to a relay server. Since proxy servers
   // usually don't handle UDP, using UDP will leak the IP address.
   PORTALLOCATOR_DISABLE_UDP_RELAY = 0x1000,
+
+  // When multiple networks exist, gather candidates only on the one with
+  // the lowest cost. So if both Wifi and Cellular networks exist, gather

[pthatcher1, 2016/05/17 20:44:28]

Cellular => cellular 
Wifi => wifi (or Wi-Fi)

[honghaiz3, 2016/05/18 05:55:02]

Done.

+  // only on the Wifi network. If a network type is "unknown", it has a cost
+  // lower than Cellular but higher than Wifi/Ethernet. So if an unknown network
+  // exists, Cellular networks will not be gathered on and if a Wifi network is

[pthatcher1, 2016/05/17 20:44:28]

gathered on => gathered on it

[honghaiz3, 2016/05/18 05:55:02]

Revised this.

+  // present, "unknown" networks will not be gathered on. Doing so ensures that

[pthatcher1, 2016/05/17 20:44:28]

networks will not be gathered on => networks will not be used for gathering

[honghaiz3, 2016/05/18 05:55:02]

Done.

+  // even if a cellular network type was not detected initially, it would not be
+  // gathered on if a Wifi network is present.
+  PORTALLOCATOR_GATHER_LOW_COST_NETWORK_ONLY = 0x2000,

[pthatcher1, 2016/05/17 20:44:28]

Following the existing naming scheme, would this be
PORTALLOCATOR_DISABLE_COSTLY_NETWORKS?

[honghaiz3, 2016/05/18 05:55:02]

Done.

 };
 
 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.
 const uint32_t kMinimumStepDelay = 50;
 
 // CF = CANDIDATE FILTER
@@ skipping 259 matching lines @@
   int target_pooled_session_count_ = 0;
   // This variable represents the total number of pooled sessions
   // both owned by this class and taken by TakePooledSession.
   int allocated_pooled_session_count_ = 0;
   std::deque<std::unique_ptr<PortAllocatorSession>> pooled_sessions_;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_PORTALLOCATOR_H_