Ping the premier connection on each network with higher priority.

webrtc/base/firewallsocketserver.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 23 matching lines @@
         SetError(EHOSTUNREACH);
         return SOCKET_ERROR;
       }
     }
     return AsyncSocketAdapter::Connect(addr);
   }
   int Send(const void* pv, size_t cb) override {
     return SendTo(pv, cb, GetRemoteAddress());
   }
   int SendTo(const void* pv, size_t cb, const SocketAddress& addr) override {
-    if (type_ == SOCK_DGRAM) {
-      if (!server_->Check(FP_UDP, GetLocalAddress(), addr)) {
-        LOG(LS_VERBOSE) << "FirewallSocket outbound UDP packet from "
-                        << GetLocalAddress().ToSensitiveString() << " to "
-                        << addr.ToSensitiveString() << " dropped";
-        return static_cast<int>(cb);
-      }
+    RTC_DCHECK(type_ == SOCK_DGRAM || type_ == SOCK_STREAM);
+    FirewallProtocol protocol = (type_ == SOCK_DGRAM) ? FP_UDP : FP_TCP;

[honghaiz3, 2016/10/03 21:28:33]

This is needed so that TCP traffic can be filtered in the middle of a call. 

+    if (!server_->Check(protocol, GetLocalAddress(), addr)) {
+      LOG(LS_VERBOSE) << "FirewallSocket outbound packet with type " << type_
+                      << " from " << GetLocalAddress().ToSensitiveString()
+                      << " to " << addr.ToSensitiveString() << " dropped";
+      return static_cast<int>(cb);
     }
     return AsyncSocketAdapter::SendTo(pv, cb, addr);
   }
   int Recv(void* pv, size_t cb, int64_t* timestamp) override {
     SocketAddress addr;
     return RecvFrom(pv, cb, &addr, timestamp);
   }
   int RecvFrom(void* pv,
                size_t cb,
                SocketAddress* paddr,
@@ skipping 183 matching lines @@
 
 void FirewallManager::ClearRules() {
   CritScope scope(&crit_);
   for (std::vector<FirewallSocketServer*>::const_iterator it =
       servers_.begin(); it != servers_.end(); ++it) {
     (*it)->ClearRules();
   }
 }
 
 }  // namespace rtc