Relanding Generate localhost candidate when no STUN/TURN and portallocator has the right flag spefi…

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 544 matching lines @@
     if ((filter & CF_REFLEXIVE) && !c.address().IsPrivateIP()) {
       // We allow host candidates if the filter allows server-reflexive
       // candidates and the candidate is a public IP. Because we don't generate
       // server-reflexive candidates if they have the same IP as the host
       // candidate (i.e. when the host candidate is a public IP), filtering to
       // only server-reflexive candidates won't work right when the host
       // candidates have public IPs.
       return true;
     }
 
+    // If PORTALLOCATOR_ENABLE_LOCALHOST_CANDIDATE is specified and it's
+    // loopback address, we should allow it as it's for demo page connectivity
+    // when no TURN/STUN specified.
+    if (c.address().IsLoopbackIP() &&
+        (flags() & PORTALLOCATOR_ENABLE_LOCALHOST_CANDIDATE) != 0) {
+      return true;
+    }
+
     // This is just to prevent the case when binding to any address (all 0s), if
     // somehow the host candidate address is not all 0s. Either because local
     // installed proxy changes the address or a packet has been sent for any
     // reason before getsockname is called.
     if (flags() & PORTALLOCATOR_DISABLE_ADAPTER_ENUMERATION) {
       LOG(LS_WARNING) << "Received non-0 host address: "
                       << c.address().ToString()
                       << " when adapter enumeration is disabled";
       return false;
     }
@@ skipping 242 matching lines @@
 
 void AllocationSequence::CreateUDPPorts() {
   if (IsFlagSet(PORTALLOCATOR_DISABLE_UDP)) {
     LOG(LS_VERBOSE) << "AllocationSequence: UDP ports disabled, skipping.";
     return;
   }
 
   // TODO(mallinath) - Remove UDPPort creating socket after shared socket
   // is enabled completely.
   UDPPort* port = NULL;
+  bool emit_localhost_for_anyaddress =
+    IsFlagSet(PORTALLOCATOR_ENABLE_LOCALHOST_CANDIDATE);
   if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET) && udp_socket_) {
-    port = UDPPort::Create(session_->network_thread(),
-                           session_->socket_factory(), network_,
-                           udp_socket_.get(),
-                           session_->username(), session_->password(),
-                           session_->allocator()->origin());
+    port = UDPPort::Create(
+        session_->network_thread(), session_->socket_factory(), network_,
+        udp_socket_.get(), session_->username(), session_->password(),
+        session_->allocator()->origin(), emit_localhost_for_anyaddress);
   } else {
-    port = UDPPort::Create(session_->network_thread(),
-                           session_->socket_factory(),
-                           network_, ip_,
-                           session_->allocator()->min_port(),
-                           session_->allocator()->max_port(),
-                           session_->username(), session_->password(),
-                           session_->allocator()->origin());
+    port = UDPPort::Create(
+        session_->network_thread(), session_->socket_factory(), network_, ip_,
+        session_->allocator()->min_port(), session_->allocator()->max_port(),
+        session_->username(), session_->password(),
+        session_->allocator()->origin(), emit_localhost_for_anyaddress);
   }
 
   if (port) {
     // If shared socket is enabled, STUN candidate will be allocated by the
     // UDPPort.
     if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET)) {
       udp_port_ = port;
       port->SignalDestroyed.connect(this, &AllocationSequence::OnPortDestroyed);
 
       // If STUN is not disabled, setting stun server address to port.
@@ skipping 275 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