gecko/media/mtransport/test_nr_socket.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
*/

/*
Based partially on original code from nICEr and nrappkit.

nICEr copyright:

Copyright (c) 2007, Adobe Systems, Incorporated
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.

* Neither the name of Adobe Systems, Network Resonance nor the names of its
  contributors may be used to endorse or promote products derived from
  this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


nrappkit copyright:

   Copyright (C) 2001-2003, Network Resonance, Inc.
   Copyright (C) 2006, Network Resonance, Inc.
   All Rights Reserved

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
   3. Neither the name of Network Resonance, Inc. nor the name of any
      contributors to this software may be used to endorse or promote
      products derived from this software without specific prior written
      permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   POSSIBILITY OF SUCH DAMAGE.


   ekr@rtfm.com  Thu Dec 20 20:14:49 2001
*/

// Original author: bcampen@mozilla.com [:bwc]

extern "C" {
#include "stun_msg.h" // for NR_STUN_MAX_MESSAGE_SIZE
#include "nr_api.h"
#include "async_wait.h"
#include "nr_socket.h"
#include "nr_socket_local.h"
#include "stun_hint.h"
#include "transport_addr.h"
}

#include "mozilla/RefPtr.h"
#include "test_nr_socket.h"
#include "runnable_utils.h"

namespace mozilla {

static int test_nat_socket_create(void *obj,
                                  nr_transport_addr *addr,
                                  nr_socket **sockp) {
  RefPtr<NrSocketBase> sock = new TestNrSocket(static_cast<TestNat*>(obj));

  int r, _status;

  r = sock->create(addr);
  if (r)
    ABORT(r);

  r = nr_socket_create_int(static_cast<void *>(sock),
                           sock->vtbl(), sockp);
  if (r)
    ABORT(r);

  _status = 0;

  {
    // We will release this reference in destroy(), not exactly the normal
    // ownership model, but it is what it is.
    NrSocketBase *dummy = sock.forget().take();
    (void)dummy;
  }

abort:
  return _status;
}

static int test_nat_socket_factory_destroy(void **obj) {
  TestNat *nat = static_cast<TestNat*>(*obj);
  *obj = nullptr;
  nat->Release();
  return 0;
}

static nr_socket_factory_vtbl test_nat_socket_factory_vtbl = {
  test_nat_socket_create,
  test_nat_socket_factory_destroy
};

bool TestNat::has_port_mappings() const {
  for (TestNrSocket *sock : sockets_) {
    if (sock->has_port_mappings()) {
      return true;
    }
  }
  return false;
}

bool TestNat::is_my_external_tuple(const nr_transport_addr &addr) const {
  for (TestNrSocket *sock : sockets_) {
    if (sock->is_my_external_tuple(addr)) {
      return true;
    }
  }

  return false;
}

bool TestNat::is_an_internal_tuple(const nr_transport_addr &addr) const {
  for (TestNrSocket *sock : sockets_) {
    nr_transport_addr addr_behind_nat;
    if (sock->getaddr(&addr_behind_nat)) {
      MOZ_CRASH("TestNrSocket::getaddr failed!");
    }

    // TODO(bug 1170299): Remove const_cast when no longer necessary
    if (!nr_transport_addr_cmp(const_cast<nr_transport_addr*>(&addr),
                               &addr_behind_nat,
                               NR_TRANSPORT_ADDR_CMP_MODE_ALL)) {
      return true;
    }
  }
  return false;
}

int TestNat::create_socket_factory(nr_socket_factory **factorypp) {
  int r = nr_socket_factory_create_int(this,
                                       &test_nat_socket_factory_vtbl,
                                       factorypp);
  if (!r) {
    AddRef();
  }
  return r;
}

TestNrSocket::TestNrSocket(TestNat *nat)
  : nat_(nat) {
  nat_->insert_socket(this);
}

TestNrSocket::~TestNrSocket() {
  nat_->erase_socket(this);
}

RefPtr<NrSocket> TestNrSocket::create_external_socket(
    const nr_transport_addr &dest_addr) const {
  MOZ_ASSERT(nat_->enabled_);
  MOZ_ASSERT(!nat_->is_an_internal_tuple(dest_addr));

  int r;
  nr_transport_addr nat_external_addr;

  // Open the socket on an arbitrary port, on the same address.
  // TODO(bug 1170299): Remove const_cast when no longer necessary
  if ((r = nr_transport_addr_copy(&nat_external_addr,
                                  const_cast<nr_transport_addr*>(&my_addr_)))) {
    r_log(LOG_GENERIC,LOG_CRIT, "%s: Failure in nr_transport_addr_copy: %d",
                                __FUNCTION__, r);
    return nullptr;
  }

  if ((r = nr_transport_addr_set_port(&nat_external_addr, 0))) {
    r_log(LOG_GENERIC,LOG_CRIT, "%s: Failure in nr_transport_addr_set_port: %d",
                                __FUNCTION__, r);
    return nullptr;
  }

  RefPtr<NrSocket> external_socket = new NrSocket;

  if ((r = external_socket->create(&nat_external_addr))) {
    r_log(LOG_GENERIC,LOG_CRIT, "%s: Failure in NrSocket::create: %d",
                                __FUNCTION__, r);
    return nullptr;
  }

  return external_socket;
}

int TestNrSocket::sendto(const void *msg, size_t len,
                         int flags, nr_transport_addr *to) {
  MOZ_ASSERT(my_addr_.protocol != IPPROTO_TCP);
  ASSERT_ON_THREAD(ststhread_);

  if (!nat_->enabled_ || nat_->is_an_internal_tuple(*to)) {
    return NrSocket::sendto(msg, len, flags, to);
  }

  destroy_stale_port_mappings();

  if (to->protocol == IPPROTO_UDP && nat_->block_udp_) {
    // Silently eat the packet
    return 0;
  }

  // Choose our port mapping based on our most selective criteria
  PortMapping *port_mapping = get_port_mapping(*to,
                                               std::max(nat_->filtering_type_,
                                                        nat_->mapping_type_));

  if (!port_mapping) {
    // See if we have already made the external socket we need to use.
    PortMapping *similar_port_mapping =
      get_port_mapping(*to, nat_->mapping_type_);
    RefPtr<NrSocket> external_socket;

    if (similar_port_mapping) {
      external_socket = similar_port_mapping->external_socket_;
    } else {
      external_socket = create_external_socket(*to);
      if (!external_socket) {
        MOZ_ASSERT(false);
        return R_INTERNAL;
      }
    }

    port_mapping = create_port_mapping(*to, external_socket);
    port_mappings_.push_back(port_mapping);

    if (poll_flags() & PR_POLL_READ) {
      // Make sure the new port mapping is ready to receive traffic if the
      // TestNrSocket is already waiting.
      port_mapping->async_wait(NR_ASYNC_WAIT_READ,
                              port_mapping_readable_callback,
                              this,
                              (char*)__FUNCTION__,
                              __LINE__);
    }
  }

  // We probably don't want to propagate the flags, since this is a simulated
  // external IP address.
  return port_mapping->sendto(msg, len, *to);
}

int TestNrSocket::recvfrom(void *buf, size_t maxlen,
                           size_t *len, int flags,
                           nr_transport_addr *from) {
  MOZ_ASSERT(my_addr_.protocol != IPPROTO_TCP);
  ASSERT_ON_THREAD(ststhread_);

  int r;
  bool ingress_allowed = false;

  if (readable_socket_) {
    // If any of the external sockets got data, see if it will be passed through
    r = readable_socket_->recvfrom(buf, maxlen, len, 0, from);
    readable_socket_ = nullptr;
    if (!r) {
      PortMapping *port_mapping_used;
      ingress_allowed = allow_ingress(*from, &port_mapping_used);
      if (ingress_allowed && nat_->refresh_on_ingress_ && port_mapping_used) {
        port_mapping_used->last_used_ = PR_IntervalNow();
      }
    }
  } else {
    // If no external socket has data, see if there's any data that was sent
    // directly to the TestNrSocket, and eat it if it isn't supposed to get
    // through.
    r = NrSocket::recvfrom(buf, maxlen, len, flags, from);
    if (!r) {
      // We do not use allow_ingress() here because that only handles traffic
      // landing on an external port.
      ingress_allowed = (!nat_->enabled_ ||
                         nat_->is_an_internal_tuple(*from));
      if (!ingress_allowed) {
        r_log(LOG_GENERIC, LOG_INFO, "TestNrSocket %s denying ingress from %s: "
                                     "Not behind the same NAT",
                                     my_addr_.as_string,
                                     from->as_string);
      }
    }
  }

  // Kinda lame that we are forced to give the app a readable callback and then
  // say "Oh, never mind...", but the alternative is to totally decouple the
  // callbacks from STS and the callbacks the app sets. On the bright side, this
  // speeds up unit tests where we are verifying that ingress is forbidden,
  // since they'll get a readable callback and then an error, instead of having
  // to wait for a timeout.
  if (!ingress_allowed) {
    *len = 0;
    r = R_WOULDBLOCK;
  }

  return r;
}

bool TestNrSocket::allow_ingress(const nr_transport_addr &from,
                                 PortMapping **port_mapping_used) const {
  *port_mapping_used = nullptr;
  if (!nat_->enabled_)
    return true;

  if (nat_->is_an_internal_tuple(from))
    return true;

  *port_mapping_used = get_port_mapping(from, nat_->filtering_type_);
  if (!(*port_mapping_used)) {
    r_log(LOG_GENERIC, LOG_INFO, "TestNrSocket %s denying ingress from %s: "
                                 "Filtered",
                                 my_addr_.as_string,
                                 from.as_string);
    return false;
  }

  if (is_port_mapping_stale(**port_mapping_used)) {
    r_log(LOG_GENERIC, LOG_INFO, "TestNrSocket %s denying ingress from %s: "
                                 "Stale port mapping",
                                 my_addr_.as_string,
                                 from.as_string);
    return false;
  }

  if (!nat_->allow_hairpinning_ && nat_->is_my_external_tuple(from)) {
    r_log(LOG_GENERIC, LOG_INFO, "TestNrSocket %s denying ingress from %s: "
                                 "Hairpinning disallowed",
                                 my_addr_.as_string,
                                 from.as_string);
    return false;
  }

  return true;
}

int TestNrSocket::connect(nr_transport_addr *addr) {
  ASSERT_ON_THREAD(ststhread_);

  if (connect_invoked_ || !port_mappings_.empty()) {
    MOZ_CRASH("TestNrSocket::connect() called more than once!");
    return R_INTERNAL;
  }

  if (!nat_->enabled_
      || addr->protocol==IPPROTO_UDP  // Horrible hack to allow default address
                                      // discovery to work. Only works because
                                      // we don't normally connect on UDP.
      || nat_->is_an_internal_tuple(*addr)) {
    // This will set connect_invoked_
    return NrSocket::connect(addr);
  }

  RefPtr<NrSocket> external_socket(create_external_socket(*addr));
  if (!external_socket) {
    return R_INTERNAL;
  }

  PortMapping *port_mapping = create_port_mapping(*addr, external_socket);
  port_mappings_.push_back(port_mapping);
  port_mapping->external_socket_->connect(addr);
  port_mapping->last_used_ = PR_IntervalNow();

  if (poll_flags() & PR_POLL_READ) {
    port_mapping->async_wait(NR_ASYNC_WAIT_READ,
                             port_mapping_tcp_passthrough_callback,
                             this,
                             (char*)__FUNCTION__,
                             __LINE__);
  }

  return 0;
}

int TestNrSocket::write(const void *msg, size_t len, size_t *written) {
  ASSERT_ON_THREAD(ststhread_);

  if (port_mappings_.empty()) {
    // The no-nat case, just pass call through.
    r_log(LOG_GENERIC, LOG_INFO, "TestNrSocket %s writing",
          my_addr().as_string);

    return NrSocket::write(msg, len, written);
  } else {
    // This is TCP only
    MOZ_ASSERT(port_mappings_.size() == 1);
    r_log(LOG_GENERIC, LOG_INFO,
          "PortMapping %s -> %s writing",
          port_mappings_.front()->external_socket_->my_addr().as_string,
          port_mappings_.front()->remote_address_.as_string);

    return port_mappings_.front()->external_socket_->write(msg, len, written);
  }
}

int TestNrSocket::read(void *buf, size_t maxlen, size_t *len) {
  ASSERT_ON_THREAD(ststhread_);

  if (port_mappings_.empty()) {
    return NrSocket::read(buf, maxlen, len);
  } else {
    MOZ_ASSERT(port_mappings_.size() == 1);
    return port_mappings_.front()->external_socket_->read(buf, maxlen, len);
  }
}

int TestNrSocket::async_wait(int how, NR_async_cb cb, void *cb_arg,
                             char *function, int line) {
  ASSERT_ON_THREAD(ststhread_);

  // Make sure we're waiting on the socket for the internal address
  int r = NrSocket::async_wait(how, cb, cb_arg, function, line);

  if (r) {
    return r;
  }

  r_log(LOG_GENERIC, LOG_DEBUG, "TestNrSocket %s waiting for %s",
                                my_addr_.as_string,
                                how == NR_ASYNC_WAIT_READ ? "read" : "write");

  if (is_tcp_connection_behind_nat()) {
    // Bypass all port-mapping related logic
    return 0;
  }

  if (my_addr_.protocol == IPPROTO_TCP) {
    // For a TCP connection through a simulated NAT, these signals are
    // just passed through.
    MOZ_ASSERT(port_mappings_.size() == 1);

    return port_mappings_.front()->async_wait(
        how,
        port_mapping_tcp_passthrough_callback,
        this,
        function,
        line);
  } else if (how == NR_ASYNC_WAIT_READ) {
    // For UDP port mappings, we decouple the writeable callbacks
    for (PortMapping *port_mapping : port_mappings_) {
      // Be ready to receive traffic on our port mappings
      r = port_mapping->async_wait(how,
                                   port_mapping_readable_callback,
                                   this,
                                   function,
                                   line);
      if (r) {
        return r;
      }
    }
  }

  return 0;
}

void TestNrSocket::cancel_port_mapping_async_wait(int how) {
  for (PortMapping *port_mapping : port_mappings_) {
    port_mapping->cancel(how);
  }
}

int TestNrSocket::cancel(int how) {
  ASSERT_ON_THREAD(ststhread_);

  r_log(LOG_GENERIC, LOG_DEBUG, "TestNrSocket %s stop waiting for %s",
        my_addr_.as_string,
        how == NR_ASYNC_WAIT_READ ? "read" : "write");

  // Writable callbacks are decoupled except for the TCP case
  if (how == NR_ASYNC_WAIT_READ || my_addr_.protocol == IPPROTO_TCP) {
    cancel_port_mapping_async_wait(how);
  }

  return NrSocket::cancel(how);
}

bool TestNrSocket::has_port_mappings() const {
  return !port_mappings_.empty();
}

bool TestNrSocket::is_my_external_tuple(const nr_transport_addr &addr) const {
  for (PortMapping *port_mapping : port_mappings_) {
    nr_transport_addr port_mapping_addr;
    if (port_mapping->external_socket_->getaddr(&port_mapping_addr)) {
      MOZ_CRASH("NrSocket::getaddr failed!");
    }

    // TODO(bug 1170299): Remove const_cast when no longer necessary
    if (!nr_transport_addr_cmp(const_cast<nr_transport_addr*>(&addr),
                               &port_mapping_addr,
                               NR_TRANSPORT_ADDR_CMP_MODE_ALL)) {
      return true;
    }
  }
  return false;
}

bool TestNrSocket::is_port_mapping_stale(
    const PortMapping &port_mapping) const {
  PRIntervalTime now = PR_IntervalNow();
  PRIntervalTime elapsed_ticks = now - port_mapping.last_used_;
  uint32_t idle_duration = PR_IntervalToMilliseconds(elapsed_ticks);
  return idle_duration > nat_->mapping_timeout_;
}

void TestNrSocket::destroy_stale_port_mappings() {
  for (auto i = port_mappings_.begin(); i != port_mappings_.end();) {
    auto temp = i;
    ++i;
    if (is_port_mapping_stale(**temp)) {
      r_log(LOG_GENERIC, LOG_INFO,
            "TestNrSocket %s destroying port mapping %s -> %s",
            my_addr_.as_string,
            (*temp)->external_socket_->my_addr().as_string,
            (*temp)->remote_address_.as_string);

      port_mappings_.erase(temp);
    }
  }
}

void TestNrSocket::port_mapping_readable_callback(void *ext_sock_v,
                                                  int how,
                                                  void *test_sock_v) {
  TestNrSocket *test_socket = static_cast<TestNrSocket*>(test_sock_v);
  NrSocket *external_socket = static_cast<NrSocket*>(ext_sock_v);

  test_socket->on_port_mapping_readable(external_socket);
}

void TestNrSocket::on_port_mapping_readable(NrSocket *external_socket) {
  if (!readable_socket_) {
    readable_socket_ = external_socket;
  }

  // None of our port mappings should be waiting for readable callbacks
  // if nobody is waiting for readable callbacks from us.
  MOZ_ASSERT(poll_flags() & PR_POLL_READ);

  fire_readable_callback();
}

void TestNrSocket::fire_readable_callback() {
  MOZ_ASSERT(poll_flags() & PR_POLL_READ);
  // Stop listening on all mapped sockets; we will start listening again
  // if the app starts listening to us again.
  cancel_port_mapping_async_wait(NR_ASYNC_WAIT_READ);
  r_log(LOG_GENERIC, LOG_DEBUG, "TestNrSocket %s ready for read",
        my_addr_.as_string);
  fire_callback(NR_ASYNC_WAIT_READ);
}

void TestNrSocket::port_mapping_writeable_callback(void *ext_sock_v,
                                                   int how,
                                                   void *test_sock_v) {
  TestNrSocket *test_socket = static_cast<TestNrSocket*>(test_sock_v);
  NrSocket *external_socket = static_cast<NrSocket*>(ext_sock_v);

  test_socket->write_to_port_mapping(external_socket);
}

void TestNrSocket::write_to_port_mapping(NrSocket *external_socket) {
  MOZ_ASSERT(my_addr_.protocol != IPPROTO_TCP);

  int r = 0;
  for (PortMapping *port_mapping : port_mappings_) {
    if (port_mapping->external_socket_ == external_socket) {
      // If the send succeeds, or if there was nothing to send, we keep going
      r = port_mapping->send_from_queue();
      if (r) {
        break;
      }
    }
  }

  if (r == R_WOULDBLOCK) {
    // Re-register for writeable callbacks, since we still have stuff to send
    NR_ASYNC_WAIT(external_socket,
                  NR_ASYNC_WAIT_WRITE,
                  &TestNrSocket::port_mapping_writeable_callback,
                  this);
  }
}

void TestNrSocket::port_mapping_tcp_passthrough_callback(void *ext_sock_v,
                                                         int how,
                                                         void *test_sock_v) {
  TestNrSocket *test_socket = static_cast<TestNrSocket*>(test_sock_v);
  r_log(LOG_GENERIC, LOG_INFO,
        "TestNrSocket %s firing %s callback",
        test_socket->my_addr().as_string,
        how == NR_ASYNC_WAIT_READ ? "readable" : "writeable");


  test_socket->fire_callback(how);
}

bool TestNrSocket::is_tcp_connection_behind_nat() const {
  return my_addr_.protocol == IPPROTO_TCP && port_mappings_.empty();
}

TestNrSocket::PortMapping* TestNrSocket::get_port_mapping(
    const nr_transport_addr &remote_address,
    TestNat::NatBehavior filter) const {
  int compare_flags;
  switch (filter) {
    case TestNat::ENDPOINT_INDEPENDENT:
      compare_flags = NR_TRANSPORT_ADDR_CMP_MODE_PROTOCOL;
      break;
    case TestNat::ADDRESS_DEPENDENT:
      compare_flags = NR_TRANSPORT_ADDR_CMP_MODE_ADDR;
      break;
    case TestNat::PORT_DEPENDENT:
      compare_flags = NR_TRANSPORT_ADDR_CMP_MODE_ALL;
      break;
  }

  for (PortMapping *port_mapping : port_mappings_) {
    // TODO(bug 1170299): Remove const_cast when no longer necessary
    if (!nr_transport_addr_cmp(const_cast<nr_transport_addr*>(&remote_address),
                               &port_mapping->remote_address_,
                               compare_flags))
      return port_mapping;
  }
  return nullptr;
}

TestNrSocket::PortMapping* TestNrSocket::create_port_mapping(
    const nr_transport_addr &remote_address,
    const RefPtr<NrSocket> &external_socket) const {
  r_log(LOG_GENERIC, LOG_INFO, "TestNrSocket %s creating port mapping %s -> %s",
        my_addr_.as_string,
        external_socket->my_addr().as_string,
        remote_address.as_string);

  return new PortMapping(remote_address, external_socket);
}

TestNrSocket::PortMapping::PortMapping(
    const nr_transport_addr &remote_address,
    const RefPtr<NrSocket> &external_socket) :
  external_socket_(external_socket) {
  // TODO(bug 1170299): Remove const_cast when no longer necessary
  nr_transport_addr_copy(&remote_address_,
                         const_cast<nr_transport_addr*>(&remote_address));
}

int TestNrSocket::PortMapping::send_from_queue() {
  MOZ_ASSERT(remote_address_.protocol != IPPROTO_TCP);
  int r = 0;

  while (!send_queue_.empty()) {
    UdpPacket &packet = *send_queue_.front();
    r_log(LOG_GENERIC, LOG_INFO,
          "PortMapping %s -> %s sending from queue to %s",
          external_socket_->my_addr().as_string,
          remote_address_.as_string,
          packet.remote_address_.as_string);

    r = external_socket_->sendto(packet.buffer_->data(),
                                 packet.buffer_->len(),
                                 0,
                                 &packet.remote_address_);

    if (r) {
      if (r != R_WOULDBLOCK) {
        r_log(LOG_GENERIC, LOG_ERR, "%s: Fatal error %d, stop trying",
              __FUNCTION__, r);
        send_queue_.clear();
      } else {
        r_log(LOG_GENERIC, LOG_INFO, "Would block, will retry later");
      }
      break;
    }

    send_queue_.pop_front();
  }

  return r;
}

int TestNrSocket::PortMapping::sendto(const void *msg,
                                      size_t len,
                                      const nr_transport_addr &to) {
  MOZ_ASSERT(remote_address_.protocol != IPPROTO_TCP);
  r_log(LOG_GENERIC, LOG_INFO,
        "PortMapping %s -> %s sending to %s",
        external_socket_->my_addr().as_string,
        remote_address_.as_string,
        to.as_string);

  last_used_ = PR_IntervalNow();
  int r = external_socket_->sendto(msg, len, 0,
      // TODO(bug 1170299): Remove const_cast when no longer necessary
      const_cast<nr_transport_addr*>(&to));

  if (r == R_WOULDBLOCK) {
    r_log(LOG_GENERIC, LOG_INFO, "Enqueueing UDP packet to %s", to.as_string);
    send_queue_.push_back(RefPtr<UdpPacket>(new UdpPacket(msg, len, to)));
    return 0;
  } else if (r) {
    r_log(LOG_GENERIC,LOG_ERR, "Error: %d", r);
  }

  return r;
}

int TestNrSocket::PortMapping::async_wait(int how, NR_async_cb cb, void *cb_arg,
                                          char *function, int line) {
  r_log(LOG_GENERIC, LOG_DEBUG,
        "PortMapping %s -> %s waiting for %s",
        external_socket_->my_addr().as_string,
        remote_address_.as_string,
        how == NR_ASYNC_WAIT_READ ? "read" : "write");

  return external_socket_->async_wait(how, cb, cb_arg, function, line);
}

int TestNrSocket::PortMapping::cancel(int how) {
  r_log(LOG_GENERIC, LOG_DEBUG,
        "PortMapping %s -> %s stop waiting for %s",
        external_socket_->my_addr().as_string,
        remote_address_.as_string,
        how == NR_ASYNC_WAIT_READ ? "read" : "write");

  return external_socket_->cancel(how);
}

} // namespace mozilla