/* -*- 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/. */

// Original author: ekr@rtfm.com

/*
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
*/
#include "logging.h"
#include "mozilla/Scoped.h"
#include "databuffer.h"

extern "C" {
#include "nr_api.h"
#include "async_wait.h"
#include "async_timer.h"
#include "nr_socket.h"
#include "nr_socket_local.h"
#include "transport_addr.h"
#include "addrs.h"
#include "local_addr.h"
#include "stun_util.h"
#include "registry.h"
}

#include "stunserver.h"

#include <string>

MOZ_MTLOG_MODULE("stunserver");

namespace mozilla {

// Wrapper nr_socket which allows us to lie to the stun server about the
// IP address.
struct nr_socket_wrapped {
  nr_socket *sock_;
  nr_transport_addr addr_;
};

static int nr_socket_wrapped_destroy(void **objp) {
  if (!objp || !*objp)
    return 0;

  nr_socket_wrapped *wrapped = static_cast<nr_socket_wrapped *>(*objp);
  *objp = 0;

  delete wrapped;

  return 0;
}

static int nr_socket_wrapped_sendto(void *obj, const void *msg, size_t len, int flags,
    nr_transport_addr *addr) {
  nr_socket_wrapped *wrapped = static_cast<nr_socket_wrapped *>(obj);

  return nr_socket_sendto(wrapped->sock_, msg, len, flags, &wrapped->addr_);
}

static int nr_socket_wrapped_recvfrom(void *obj, void * restrict buf, size_t maxlen,
    size_t *len, int flags, nr_transport_addr *addr) {
  MOZ_CRASH();
}

static int nr_socket_wrapped_getfd(void *obj, NR_SOCKET *fd) {
  MOZ_CRASH();
}

static int nr_socket_wrapped_getaddr(void *obj, nr_transport_addr *addrp) {
  nr_socket_wrapped *wrapped = static_cast<nr_socket_wrapped *>(obj);

  return nr_socket_getaddr(wrapped->sock_, addrp);
}

static int nr_socket_wrapped_close(void *obj) {
  MOZ_CRASH();
}

static int nr_socket_wrapped_set_send_addr(nr_socket *sock, nr_transport_addr *addr) {
  nr_socket_wrapped *wrapped = static_cast<nr_socket_wrapped *>(sock->obj);

  return nr_transport_addr_copy(&wrapped->addr_, addr);
}

static nr_socket_vtbl nr_socket_wrapped_vtbl = {
  1,
  nr_socket_wrapped_destroy,
  nr_socket_wrapped_sendto,
  nr_socket_wrapped_recvfrom,
  nr_socket_wrapped_getfd,
  nr_socket_wrapped_getaddr,
  0,
  0,
  0,
  nr_socket_wrapped_close
};

int nr_socket_wrapped_create(nr_socket *inner, nr_socket **outp) {
  ScopedDeletePtr<nr_socket_wrapped> wrapped(new nr_socket_wrapped());

  wrapped->sock_ = inner;

  int r = nr_socket_create_int(wrapped.get(), &nr_socket_wrapped_vtbl, outp);
  if (r)
    return r;

  wrapped.forget();
  return 0;
}


// Instance static.
// Note: Calling Create() at static init time is not going to be safe, since
// we have no reason to expect this will be initted to a nullptr yet.
TestStunServer* TestStunServer::instance;
uint16_t TestStunServer::instance_port = 3478;

TestStunServer::~TestStunServer() {
  // TODO(ekr@rtfm.com): Put this on the right thread.

  // Unhook callback from our listen socket.
  if (listen_sock_) {
    NR_SOCKET fd;
    if (!nr_socket_getfd(listen_sock_, &fd)) {
      NR_ASYNC_CANCEL(fd, NR_ASYNC_WAIT_READ);
    }
  }

  // Free up stun context and network resources
  nr_stun_server_ctx_destroy(&stun_server_);
  nr_socket_destroy(&listen_sock_);
  nr_socket_destroy(&send_sock_);

  // Make sure we aren't still waiting on a deferred response timer to pop
  if (timer_handle_)
    NR_async_timer_cancel(timer_handle_);

  delete response_addr_;
}

int TestStunServer::TryOpenListenSocket(nr_local_addr* addr, uint16_t port) {

    if (nr_transport_addr_set_port(&addr->addr, port)) {
      MOZ_MTLOG(ML_ERROR, "Couldn't set port");
      return R_INTERNAL;
    }

    if (nr_transport_addr_fmt_addr_string(&addr->addr)) {
      MOZ_MTLOG(ML_ERROR, "Couldn't re-set addr string");
      return R_INTERNAL;
    }

    if (nr_socket_local_create(&addr->addr, &listen_sock_)) {
      MOZ_MTLOG(ML_ERROR, "Couldn't create listen socket");
      return R_ALREADY;
    }

    return 0;
}

TestStunServer* TestStunServer::Create() {
  NR_reg_init(NR_REG_MODE_LOCAL);

  ScopedDeletePtr<TestStunServer> server(new TestStunServer());

  nr_local_addr addrs[100];
  int addr_ct;
  int r;

  r = nr_stun_find_local_addresses(addrs, 100, &addr_ct);
  if (r) {
    MOZ_MTLOG(ML_ERROR, "Couldn't retrieve addresses");
    return nullptr;
  }

  if (addr_ct < 1) {
    MOZ_MTLOG(ML_ERROR, "No local addresses");
    return nullptr;
  }

  NR_SOCKET fd;
  int tries = 100;
  while (tries--) {
    // Bind to the first address (arbitrarily) on configured port (default 3478)
    r = server->TryOpenListenSocket(&addrs[0], instance_port);
    // We interpret R_ALREADY to mean the addr is probably in use. Try another.
    // Otherwise, it either worked or it didn't, and we check below.
    if (r != R_ALREADY) {
      break;
    }
    ++instance_port;
  }

  if (r) {
    return nullptr;
  }

  r = nr_socket_getfd(server->listen_sock_, &fd);
  if (r) {
    MOZ_MTLOG(ML_ERROR, "Couldn't get fd");
    return nullptr;
  }

  r = nr_socket_wrapped_create(server->listen_sock_, &server->send_sock_);
  if (r) {
    MOZ_MTLOG(ML_ERROR, "Couldn't create send socket");
    return nullptr;
  }

  r = nr_stun_server_ctx_create(const_cast<char *>("Test STUN server"),
                                server->send_sock_,
                                &server->stun_server_);
  if (r) {
    MOZ_MTLOG(ML_ERROR, "Couldn't create STUN server");
    return nullptr;
  }

  // Cache the address and port.
  char addr_string[INET6_ADDRSTRLEN];
  r = nr_transport_addr_get_addrstring(&addrs[0].addr, addr_string,
                                       sizeof(addr_string));
  if (r) {
    MOZ_MTLOG(ML_ERROR, "Failed to convert listen addr to a string representation");
    return nullptr;
  }

  server->listen_addr_ = addr_string;
  server->listen_port_ = instance_port;

  NR_ASYNC_WAIT(fd, NR_ASYNC_WAIT_READ, &TestStunServer::readable_cb, server.get());

  return server.forget();
}

void TestStunServer::ConfigurePort(uint16_t port) {
  instance_port = port;
}

TestStunServer* TestStunServer::GetInstance() {
  if (!instance)
    instance = Create();

  MOZ_ASSERT(instance);
  return instance;
}

void TestStunServer::ShutdownInstance() {
  delete instance;

  instance = nullptr;
}


struct DeferredStunOperation {
  DeferredStunOperation(TestStunServer *server,
                        const char *data, size_t len,
                        nr_transport_addr *addr) :
      server_(server),
      buffer_(reinterpret_cast<const uint8_t *>(data), len) {
    nr_transport_addr_copy(&addr_, addr);
  }

  TestStunServer *server_;
  DataBuffer buffer_;
  nr_transport_addr addr_;
};

void TestStunServer::Process(const uint8_t *msg, size_t len, nr_transport_addr *addr) {
  // Set the wrapped address so that the response goes to the right place.
  nr_socket_wrapped_set_send_addr(send_sock_, addr);
  nr_stun_server_process_request(stun_server_, send_sock_,
                                 const_cast<char *>(reinterpret_cast<const char *>(msg)),
                                 len,
                                 response_addr_ ?
                                 response_addr_ : addr,
                                 NR_STUN_AUTH_RULE_OPTIONAL);
}

void TestStunServer::process_cb(NR_SOCKET s, int how, void *cb_arg) {
  DeferredStunOperation *op = static_cast<DeferredStunOperation *>(cb_arg);
  op->server_->timer_handle_ = nullptr;
  op->server_->Process(op->buffer_.data(), op->buffer_.len(), &op->addr_);

  delete op;
}

void TestStunServer::readable_cb(NR_SOCKET s, int how, void *cb_arg) {
  TestStunServer* server = static_cast<TestStunServer*>(cb_arg);

  char message[4096];
  size_t message_len;
  nr_transport_addr addr;

  int r = nr_socket_recvfrom(server->listen_sock_, message, sizeof(message),
    &message_len, 0, &addr);

  if (r) {
    MOZ_MTLOG(ML_ERROR, "Couldn't read STUN message");
    return;
  }

  MOZ_MTLOG(ML_DEBUG, "Received data of length " << message_len);

  // Re-arm.
  NR_ASYNC_WAIT(s, NR_ASYNC_WAIT_READ, &TestStunServer::readable_cb, server);


  // If we have initial dropping set, check at this point.
  std::string key(addr.as_string);

  if (server->received_ct_.count(key) == 0) {
    server->received_ct_[key] = 0;
  }

  ++server->received_ct_[key];

  if (!server->active_ || (server->received_ct_[key] <= server->initial_ct_)) {
    MOZ_MTLOG(ML_DEBUG, "Dropping message #"
              << server->received_ct_[key] << " from " << key);
    return;
  }

  if (server->delay_ms_) {
    NR_ASYNC_TIMER_SET(server->delay_ms_,
                       process_cb,
                       new DeferredStunOperation(
                           server,
                           message, message_len,
                           &addr),
                       &server->timer_handle_);
  } else {
    server->Process(reinterpret_cast<const uint8_t *>(message), message_len, &addr);
  }
}

void TestStunServer::SetActive(bool active) {
  active_ = active;
}

void TestStunServer::SetDelay(uint32_t delay_ms) {
  delay_ms_ = delay_ms;
}

void TestStunServer::SetDropInitialPackets(uint32_t count) {
  initial_ct_ = count;
}

nsresult TestStunServer::SetResponseAddr(nr_transport_addr *addr) {
  delete response_addr_;

  response_addr_ = new nr_transport_addr();

  int r = nr_transport_addr_copy(response_addr_, addr);
  if (r)
    return NS_ERROR_FAILURE;

  return NS_OK;
}

nsresult TestStunServer::SetResponseAddr(const std::string& addr,
                                         uint16_t port) {
  nr_transport_addr addr2;

  int r = nr_ip4_str_port_to_transport_addr(addr.c_str(),
                                            port, IPPROTO_UDP,
                                            &addr2);
  if (r)
    return NS_ERROR_FAILURE;

  return SetResponseAddr(&addr2);
}

void TestStunServer::Reset() {
  delay_ms_ = 0;
  if (timer_handle_) {
    NR_async_timer_cancel(timer_handle_);
    timer_handle_ = nullptr;
  }
  delete response_addr_;
  response_addr_ = nullptr;
}

}  // close namespace