Send back ping response if the ping comes from an unknown address.

webrtc/p2p/base/port.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 549 matching lines @@
           << "Received a remote ping with high retransmit count: "
           << retransmit_attr->value();
     }
   }
 
   response.AddAttribute(
       new StunXorAddressAttribute(STUN_ATTR_XOR_MAPPED_ADDRESS, addr));
   response.AddMessageIntegrity(password_);
   response.AddFingerprint();
 
-  // The fact that we received a successful request means that this connection
-  // (if one exists) should now be receiving.
-  Connection* conn = GetConnection(addr);
-
   // Send the response message.
   rtc::ByteBuffer buf;
   response.Write(&buf);
   rtc::PacketOptions options(DefaultDscpValue());
   auto err = SendTo(buf.Data(), buf.Length(), addr, options, false);
   if (err < 0) {
     LOG_J(LS_ERROR, this)
         << "Failed to send STUN ping response"
         << ", to=" << addr.ToSensitiveString()
         << ", err=" << err
         << ", id=" << rtc::hex_encode(response.transaction_id());
   } else {
     // Log at LS_INFO if we send a stun ping response on an unwritable
     // connection.
+    Connection* conn = GetConnection(addr);
     rtc::LoggingSeverity sev = (conn && !conn->writable()) ?
         rtc::LS_INFO : rtc::LS_VERBOSE;
     LOG_JV(sev, this)
         << "Sent STUN ping response"
         << ", to=" << addr.ToSensitiveString()
         << ", id=" << rtc::hex_encode(response.transaction_id());
   }
-
-  ASSERT(conn != NULL);
-  if (conn)
-    conn->ReceivedPing();
 }
 
 void Port::SendBindingErrorResponse(StunMessage* request,
                                     const rtc::SocketAddress& addr,
                                     int error_code, const std::string& reason) {
   ASSERT(request->type() == STUN_BINDING_REQUEST);
 
   // Fill in the response message.
   StunMessage response;
   response.SetType(STUN_BINDING_ERROR_RESPONSE);
@@ skipping 308 matching lines @@
     // If this is a STUN request, then update the receiving bit and respond.
     // If this is a STUN response, then update the writable bit.
     // Log at LS_INFO if we receive a ping on an unwritable connection.
     rtc::LoggingSeverity sev = (!writable() ? rtc::LS_INFO : rtc::LS_VERBOSE);
     switch (msg->type()) {
       case STUN_BINDING_REQUEST:
         LOG_JV(sev, this) << "Received STUN ping"
                           << ", id=" << rtc::hex_encode(msg->transaction_id());
 
         if (remote_ufrag == remote_candidate_.username()) {
-          // Check for role conflicts.
-          if (!port_->MaybeIceRoleConflict(addr, msg.get(), remote_ufrag)) {
-            // Received conflicting role from the peer.
-            LOG(LS_INFO) << "Received conflicting role from the peer.";
-            return;
-          }
-
-          // Incoming, validated stun request from remote peer.
-          // This call will also set the connection receiving.
-          port_->SendBindingResponse(msg.get(), addr);
-
-          // If timed out sending writability checks, start up again
-          if (!pruned_ && (write_state_ == STATE_WRITE_TIMEOUT))
-            set_write_state(STATE_WRITE_INIT);
-
-          if (port_->GetIceRole() == ICEROLE_CONTROLLED) {
-            const StunByteStringAttribute* use_candidate_attr =
-                msg->GetByteString(STUN_ATTR_USE_CANDIDATE);
-            if (use_candidate_attr) {
-              set_nominated(true);
-              SignalNominated(this);
-            }
-          }
+          HandleBindingRequest(msg.get());
         } else {
           // The packet had the right local username, but the remote username
           // was not the right one for the remote address.
           LOG_J(LS_ERROR, this)
             << "Received STUN request with bad remote username "
             << remote_ufrag;
           port_->SendBindingErrorResponse(msg.get(), addr,
                                           STUN_ERROR_UNAUTHORIZED,
                                           STUN_ERROR_REASON_UNAUTHORIZED);
 
@@ skipping 19 matching lines @@
         ReceivedPing();
         break;
 
       default:
         ASSERT(false);
         break;
     }
   }
 }
 
+void Connection::HandleBindingRequest(IceMessage* msg) {
+  // This connection should now be receiving.
+  ReceivedPing();
+
+  const rtc::SocketAddress& addr(remote_candidate_.address());
+  const std::string& remote_ufrag = remote_candidate_.username();

[pthatcher1, 2015/11/11 01:19:12]

Nit: to be consistent, the first line should be:

const rtc::SocketAddress remote_addr = remote_candidate_.address();

[honghaiz3, 2015/11/11 19:28:09]

Done. I kept the reference to avoid a copy. 

+  // Check for role conflicts.
+  if (!port_->MaybeIceRoleConflict(addr, msg, remote_ufrag)) {
+    // Received conflicting role from the peer.
+    LOG(LS_INFO) << "Received conflicting role from the peer.";
+    return;
+  }
+
+  // This is a validated stun request from remote peer.
+  port_->SendBindingResponse(msg, addr);
+
+  // If it timed out on writing check, start up again
+  if (!pruned_ && write_state_ == STATE_WRITE_TIMEOUT) {
+    set_write_state(STATE_WRITE_INIT);
+  }
+
+  if (port_->GetIceRole() == ICEROLE_CONTROLLED) {
+    const StunByteStringAttribute* use_candidate_attr =
+        msg->GetByteString(STUN_ATTR_USE_CANDIDATE);
+    if (use_candidate_attr) {
+      set_nominated(true);
+      SignalNominated(this);
+    }
+  }
+}
+
 void Connection::OnReadyToSend() {
   if (write_state_ == STATE_WRITABLE) {
     SignalReadyToSend(this);
   }
 }
 
 void Connection::Prune() {
   if (!pruned_ || active()) {
     LOG_J(LS_VERBOSE, this) << "Connection pruned";
     pruned_ = true;
@@ skipping 415 matching lines @@
     ASSERT(sent < 0);
     error_ = port_->GetError();
     sent_packets_discarded_++;
   } else {
     send_rate_tracker_.AddSamples(sent);
   }
   return sent;
 }
 
 }  // namespace cricket