// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "services/network/p2p/socket_tcp.h"

#include <stddef.h>
#include <utility>

#include "base/bind.h"
#include "base/sys_byteorder.h"
#include "base/threading/thread_task_runner_handle.h"
#include "base/time/time.h"
#include "jingle/glue/fake_ssl_client_socket.h"
#include "net/base/io_buffer.h"
#include "net/base/net_errors.h"
#include "net/socket/client_socket_factory.h"
#include "net/socket/client_socket_handle.h"
#include "net/socket/ssl_client_socket.h"
#include "net/socket/tcp_client_socket.h"
#include "services/network/proxy_resolving_client_socket.h"
#include "services/network/proxy_resolving_client_socket_factory.h"
#include "services/network/public/cpp/p2p_param_traits.h"
#include "third_party/webrtc/media/base/rtp_utils.h"
#include "url/gurl.h"

namespace network {
namespace {

typedef uint16_t PacketLength;
const int kPacketHeaderSize = sizeof(PacketLength);
const int kTcpReadBufferSize = 4096;
const int kPacketLengthOffset = 2;
const int kTurnChannelDataHeaderSize = 4;
const int kTcpRecvSocketBufferSize = 128 * 1024;
const int kTcpSendSocketBufferSize = 128 * 1024;

bool IsTlsClientSocket(P2PSocketType type) {
  return (type == P2P_SOCKET_STUN_TLS_CLIENT || type == P2P_SOCKET_TLS_CLIENT);
}

bool IsPseudoTlsClientSocket(P2PSocketType type) {
  return (type == P2P_SOCKET_SSLTCP_CLIENT ||
          type == P2P_SOCKET_STUN_SSLTCP_CLIENT);
}

}  // namespace

P2PSocketTcp::SendBuffer::SendBuffer() : rtc_packet_id(-1) {}
P2PSocketTcp::SendBuffer::SendBuffer(
    int32_t rtc_packet_id,
    scoped_refptr<net::DrainableIOBuffer> buffer,
    const net::NetworkTrafficAnnotationTag traffic_annotation)
    : rtc_packet_id(rtc_packet_id),
      buffer(buffer),
      traffic_annotation(traffic_annotation) {}
P2PSocketTcp::SendBuffer::SendBuffer(const SendBuffer& rhs) = default;
P2PSocketTcp::SendBuffer::~SendBuffer() = default;

P2PSocketTcpBase::P2PSocketTcpBase(
    Delegate* delegate,
    mojo::PendingRemote<mojom::P2PSocketClient> client,
    mojo::PendingReceiver<mojom::P2PSocket> socket,
    P2PSocketType type,
    ProxyResolvingClientSocketFactory* proxy_resolving_socket_factory)
    : P2PSocket(delegate, std::move(client), std::move(socket), P2PSocket::TCP),
      type_(type),
      proxy_resolving_socket_factory_(proxy_resolving_socket_factory) {}

P2PSocketTcpBase::~P2PSocketTcpBase() = default;

void P2PSocketTcpBase::InitAccepted(const net::IPEndPoint& remote_address,
                                    std::unique_ptr<net::StreamSocket> socket) {
  DCHECK(socket);
  remote_address_.ip_address = remote_address;
  // TODO(ronghuawu): Add FakeSSLServerSocket.
  socket_ = std::move(socket);
  DoRead();
}

void P2PSocketTcpBase::Init(const net::IPEndPoint& local_address,
                            uint16_t min_port,
                            uint16_t max_port,
                            const P2PHostAndIPEndPoint& remote_address) {
  DCHECK(!socket_);

  remote_address_ = remote_address;

  net::HostPortPair dest_host_port_pair;
  // If there is a domain name, let's try it first, it's required by some proxy
  // to only take hostname for CONNECT. If it has been DNS resolved, the result
  // is likely cached and shouldn't cause 2nd DNS resolution in the case of
  // direct connect (i.e. no proxy).
  if (!remote_address.hostname.empty()) {
    dest_host_port_pair = net::HostPortPair(remote_address.hostname,
                                            remote_address.ip_address.port());
  } else {
    DCHECK(!remote_address.ip_address.address().empty());
    dest_host_port_pair =
        net::HostPortPair::FromIPEndPoint(remote_address.ip_address);
  }

  // TODO(mallinath) - We are ignoring local_address altogether. We should
  // find a way to inject this into ProxyResolvingClientSocket. This could be
  // a problem on multi-homed host.

  socket_ = proxy_resolving_socket_factory_->CreateSocket(
      GURL("https://" + dest_host_port_pair.ToString()),
      IsTlsClientSocket(type_));

  if (IsPseudoTlsClientSocket(type_)) {
    socket_ =
        std::make_unique<jingle_glue::FakeSSLClientSocket>(std::move(socket_));
  }

  int status = socket_->Connect(
      base::BindOnce(&P2PSocketTcpBase::OnConnected, base::Unretained(this)));
  if (status != net::ERR_IO_PENDING)
    OnConnected(status);
}

void P2PSocketTcpBase::OnConnected(int result) {
  DCHECK_NE(result, net::ERR_IO_PENDING);

  if (result != net::OK) {
    LOG(WARNING) << "Error from connecting socket, result=" << result;
    OnError();
    return;
  }

  OnOpen();
}

void P2PSocketTcpBase::OnOpen() {
  // Setting socket send and receive buffer size.
  if (net::OK != socket_->SetReceiveBufferSize(kTcpRecvSocketBufferSize)) {
    LOG(WARNING) << "Failed to set socket receive buffer size to "
                 << kTcpRecvSocketBufferSize;
  }

  if (net::OK != socket_->SetSendBufferSize(kTcpSendSocketBufferSize)) {
    LOG(WARNING) << "Failed to set socket send buffer size to "
                 << kTcpSendSocketBufferSize;
  }

  if (!DoSendSocketCreateMsg())
    return;

  DoRead();
}

bool P2PSocketTcpBase::DoSendSocketCreateMsg() {
  DCHECK(socket_.get());

  net::IPEndPoint local_address;
  int result = socket_->GetLocalAddress(&local_address);
  if (result < 0) {
    LOG(ERROR) << "P2PSocketTcpBase::OnConnected: unable to get local"
               << " address: " << result;
    OnError();
    return false;
  }

  VLOG(1) << "Local address: " << local_address.ToString();

  net::IPEndPoint remote_address;

  // GetPeerAddress returns ERR_NAME_NOT_RESOLVED if the socket is connected
  // through a proxy.
  result = socket_->GetPeerAddress(&remote_address);
  if (result < 0 && result != net::ERR_NAME_NOT_RESOLVED) {
    LOG(ERROR) << "P2PSocketTcpBase::OnConnected: unable to get peer"
               << " address: " << result;
    OnError();
    return false;
  }

  if (!remote_address.address().empty()) {
    VLOG(1) << "Remote address: " << remote_address.ToString();
    if (remote_address_.ip_address.address().empty()) {
      // Save |remote_address| if address is empty.
      remote_address_.ip_address = remote_address;
    }
  } else {
    VLOG(1) << "Remote address is unknown since connection is proxied";
  }

  // If we are not doing TLS, we are ready to send data now.
  // In case of TLS SignalConnect will be sent only after TLS handshake is
  // successful. So no buffering will be done at socket handlers if any
  // packets sent before that by the application.
  client_->SocketCreated(local_address, remote_address);
  return true;
}

void P2PSocketTcpBase::DoRead() {
  while (true) {
    if (!read_buffer_.get()) {
      read_buffer_ = base::MakeRefCounted<net::GrowableIOBuffer>();
      read_buffer_->SetCapacity(kTcpReadBufferSize);
    } else if (read_buffer_->RemainingCapacity() < kTcpReadBufferSize) {
      // Make sure that we always have at least kTcpReadBufferSize of
      // remaining capacity in the read buffer. Normally all packets
      // are smaller than kTcpReadBufferSize, so this is not really
      // required.
      read_buffer_->SetCapacity(read_buffer_->capacity() + kTcpReadBufferSize -
                                read_buffer_->RemainingCapacity());
    }
    const int result = socket_->Read(
        read_buffer_.get(), read_buffer_->RemainingCapacity(),
        base::BindOnce(&P2PSocketTcp::OnRead, base::Unretained(this)));
    if (result == net::ERR_IO_PENDING || !HandleReadResult(result))
      return;
  }
}

void P2PSocketTcpBase::OnRead(int result) {
  if (HandleReadResult(result))
    DoRead();
}

bool P2PSocketTcpBase::OnPacket(std::vector<int8_t> data) {
  if (!connected_) {
    P2PSocket::StunMessageType type;
    bool stun = GetStunPacketType(reinterpret_cast<uint8_t*>(&*data.begin()),
                                  data.size(), &type);
    if (stun && IsRequestOrResponse(type)) {
      connected_ = true;
    } else if (!stun || type == STUN_DATA_INDICATION) {
      LOG(ERROR) << "Received unexpected data packet from "
                 << remote_address_.ip_address.ToString()
                 << " before STUN binding is finished. "
                 << "Terminating connection.";
      OnError();
      return false;
    }
  }

  client_->DataReceived(
      remote_address_.ip_address, data,
      base::TimeTicks() + base::TimeDelta::FromNanoseconds(rtc::TimeNanos()));

  delegate_->DumpPacket(
      base::make_span(reinterpret_cast<const uint8_t*>(&data[0]), data.size()),
      true);

  return true;
}

void P2PSocketTcpBase::WriteOrQueue(SendBuffer& send_buffer) {
  IncrementTotalSentPackets();
  if (write_buffer_.buffer.get()) {
    write_queue_.push(send_buffer);
    IncrementDelayedPackets();
    IncrementDelayedBytes(send_buffer.buffer->size());
    return;
  }

  write_buffer_ = send_buffer;
  DoWrite();
}

void P2PSocketTcpBase::DoWrite() {
  while (!write_pending_ && write_buffer_.buffer.get()) {
    int result = socket_->Write(
        write_buffer_.buffer.get(), write_buffer_.buffer->BytesRemaining(),
        base::BindOnce(&P2PSocketTcp::OnWritten, base::Unretained(this)),
        net::NetworkTrafficAnnotationTag(write_buffer_.traffic_annotation));

    if (result == net::ERR_IO_PENDING) {
      write_pending_ = true;
    } else if (!HandleWriteResult(result)) {
      break;
    }
  }
}

void P2PSocketTcpBase::OnWritten(int result) {
  DCHECK(write_pending_);
  DCHECK_NE(result, net::ERR_IO_PENDING);

  write_pending_ = false;

  if (HandleWriteResult(result))
    DoWrite();
}

bool P2PSocketTcpBase::HandleWriteResult(int result) {
  DCHECK(write_buffer_.buffer.get());

  if (result < 0) {
    ReportSocketError(result, "WebRTC.ICE.TcpSocketWriteErrorCode");

    LOG(ERROR) << "Error when sending data in TCP socket: " << result;
    OnError();
    return false;
  }

  write_buffer_.buffer->DidConsume(result);
  if (write_buffer_.buffer->BytesRemaining() == 0) {
    int64_t send_time_ms = rtc::TimeMillis();
    client_->SendComplete(
        P2PSendPacketMetrics(0, write_buffer_.rtc_packet_id, send_time_ms));
    if (write_queue_.empty()) {
      write_buffer_.buffer = nullptr;
      write_buffer_.rtc_packet_id = -1;
    } else {
      write_buffer_ = write_queue_.front();
      write_queue_.pop();
      // Update how many bytes are still waiting to be sent.
      DecrementDelayedBytes(write_buffer_.buffer->size());
    }
  }
  return true;
}

bool P2PSocketTcpBase::HandleReadResult(int result) {
  if (result < 0) {
    LOG(ERROR) << "Error when reading from TCP socket: " << result;
    OnError();
    return false;
  } else if (result == 0) {
    LOG(WARNING) << "Remote peer has shutdown TCP socket.";
    OnError();
    return false;
  }

  read_buffer_->set_offset(read_buffer_->offset() + result);
  char* head = read_buffer_->StartOfBuffer();  // Purely a convenience.
  int pos = 0;
  while (pos <= read_buffer_->offset()) {
    size_t bytes_consumed = 0;
    if (!ProcessInput(head + pos, read_buffer_->offset() - pos,
                      &bytes_consumed)) {
      return false;
    }
    if (!bytes_consumed)
      break;
    pos += bytes_consumed;
  }
  // We've consumed all complete packets from the buffer; now move any remaining
  // bytes to the head of the buffer and set offset to reflect this.
  if (pos && pos <= read_buffer_->offset()) {
    memmove(head, head + pos, read_buffer_->offset() - pos);
    read_buffer_->set_offset(read_buffer_->offset() - pos);
  }

  return true;
}

void P2PSocketTcpBase::Send(
    const std::vector<int8_t>& data,
    const P2PPacketInfo& packet_info,
    const net::MutableNetworkTrafficAnnotationTag& traffic_annotation) {
  // Renderer should use this socket only to send data to |remote_address_|.
  if (data.size() > kMaximumPacketSize ||
      !(packet_info.destination == remote_address_.ip_address)) {
    NOTREACHED();
    OnError();
    return;
  }

  if (!connected_) {
    P2PSocket::StunMessageType type = P2PSocket::StunMessageType();
    bool stun = GetStunPacketType(
        reinterpret_cast<const uint8_t*>(&*data.begin()), data.size(), &type);
    if (!stun || type == STUN_DATA_INDICATION) {
      LOG(ERROR) << "Page tried to send a data packet to "
                 << packet_info.destination.ToString()
                 << " before STUN binding is finished.";
      OnError();
      return;
    }
  }

  DoSend(packet_info.destination, data, packet_info.packet_options,
         net::NetworkTrafficAnnotationTag(traffic_annotation));
}

void P2PSocketTcpBase::SetOption(P2PSocketOption option, int32_t value) {
  switch (option) {
    case P2P_SOCKET_OPT_RCVBUF:
      socket_->SetReceiveBufferSize(value);
      break;
    case P2P_SOCKET_OPT_SNDBUF:
      socket_->SetSendBufferSize(value);
      break;
    case P2P_SOCKET_OPT_DSCP:
      return;  // For TCP sockets DSCP setting is not available.
    default:
      NOTREACHED();
      return;
  }
}

P2PSocketTcp::P2PSocketTcp(
    Delegate* delegate,
    mojo::PendingRemote<mojom::P2PSocketClient> client,
    mojo::PendingReceiver<mojom::P2PSocket> socket,
    P2PSocketType type,
    ProxyResolvingClientSocketFactory* proxy_resolving_socket_factory)
    : P2PSocketTcpBase(delegate,
                       std::move(client),
                       std::move(socket),
                       type,
                       proxy_resolving_socket_factory) {
  DCHECK(type == P2P_SOCKET_TCP_CLIENT || type == P2P_SOCKET_SSLTCP_CLIENT ||
         type == P2P_SOCKET_TLS_CLIENT);
}

P2PSocketTcp::~P2PSocketTcp() {}

bool P2PSocketTcp::ProcessInput(char* input,
                                int input_len,
                                size_t* bytes_consumed) {
  *bytes_consumed = 0;
  if (input_len < kPacketHeaderSize)
    return true;

  int packet_size = base::NetToHost16(*reinterpret_cast<uint16_t*>(input));
  if (input_len < packet_size + kPacketHeaderSize)
    return true;

  char* cur = input + kPacketHeaderSize;
  *bytes_consumed = kPacketHeaderSize + packet_size;

  return OnPacket(std::vector<int8_t>(cur, cur + packet_size));
}

void P2PSocketTcp::DoSend(
    const net::IPEndPoint& to,
    const std::vector<int8_t>& data,
    const rtc::PacketOptions& options,
    const net::NetworkTrafficAnnotationTag traffic_annotation) {
  int size = kPacketHeaderSize + data.size();
  SendBuffer send_buffer(options.packet_id,
                         base::MakeRefCounted<net::DrainableIOBuffer>(
                             base::MakeRefCounted<net::IOBuffer>(size), size),
                         traffic_annotation);
  *reinterpret_cast<uint16_t*>(send_buffer.buffer->data()) =
      base::HostToNet16(data.size());
  memcpy(send_buffer.buffer->data() + kPacketHeaderSize, &data[0], data.size());

  cricket::ApplyPacketOptions(
      reinterpret_cast<uint8_t*>(send_buffer.buffer->data()) +
          kPacketHeaderSize,
      send_buffer.buffer->BytesRemaining() - kPacketHeaderSize,
      options.packet_time_params, rtc::TimeMicros());

  WriteOrQueue(send_buffer);
}

// P2PSocketStunTcp
P2PSocketStunTcp::P2PSocketStunTcp(
    Delegate* delegate,
    mojo::PendingRemote<mojom::P2PSocketClient> client,
    mojo::PendingReceiver<mojom::P2PSocket> socket,
    P2PSocketType type,
    ProxyResolvingClientSocketFactory* proxy_resolving_socket_factory)
    : P2PSocketTcpBase(delegate,
                       std::move(client),
                       std::move(socket),
                       type,
                       proxy_resolving_socket_factory) {
  DCHECK(type == P2P_SOCKET_STUN_TCP_CLIENT ||
         type == P2P_SOCKET_STUN_SSLTCP_CLIENT ||
         type == P2P_SOCKET_STUN_TLS_CLIENT);
}

P2PSocketStunTcp::~P2PSocketStunTcp() {}

bool P2PSocketStunTcp::ProcessInput(char* input,
                                    int input_len,
                                    size_t* bytes_consumed) {
  *bytes_consumed = 0;
  if (input_len < kPacketHeaderSize + kPacketLengthOffset)
    return true;

  int pad_bytes;
  int packet_size = GetExpectedPacketSize(
      reinterpret_cast<const uint8_t*>(input), input_len, &pad_bytes);

  if (input_len < packet_size + pad_bytes)
    return true;

  // We have a complete packet. Read through it.
  char* cur = input;
  *bytes_consumed = packet_size + pad_bytes;
  return OnPacket(std::vector<int8_t>(cur, cur + packet_size));
}

void P2PSocketStunTcp::DoSend(
    const net::IPEndPoint& to,
    const std::vector<int8_t>& data,
    const rtc::PacketOptions& options,
    const net::NetworkTrafficAnnotationTag traffic_annotation) {
  // Each packet is expected to have header (STUN/TURN ChannelData), where
  // header contains message type and and length of message.
  if (data.size() < kPacketHeaderSize + kPacketLengthOffset) {
    NOTREACHED();
    OnError();
    return;
  }

  int pad_bytes;
  size_t expected_len = GetExpectedPacketSize(
      reinterpret_cast<const uint8_t*>(&data[0]), data.size(), &pad_bytes);

  // Accepts only complete STUN/TURN packets.
  if (data.size() != expected_len) {
    NOTREACHED();
    OnError();
    return;
  }

  // Add any pad bytes to the total size.
  int size = data.size() + pad_bytes;

  SendBuffer send_buffer(options.packet_id,
                         base::MakeRefCounted<net::DrainableIOBuffer>(
                             base::MakeRefCounted<net::IOBuffer>(size), size),
                         traffic_annotation);
  memcpy(send_buffer.buffer->data(), &data[0], data.size());

  cricket::ApplyPacketOptions(
      reinterpret_cast<uint8_t*>(send_buffer.buffer->data()), data.size(),
      options.packet_time_params, rtc::TimeMicros());

  if (pad_bytes) {
    char padding[4] = {0};
    DCHECK_LE(pad_bytes, 4);
    memcpy(send_buffer.buffer->data() + data.size(), padding, pad_bytes);
  }

  // WriteOrQueue may free the memory, so dump it first.
  delegate_->DumpPacket(
      base::make_span(reinterpret_cast<uint8_t*>(send_buffer.buffer->data()),
                      data.size()),
      false);

  WriteOrQueue(send_buffer);
}

int P2PSocketStunTcp::GetExpectedPacketSize(const uint8_t* data,
                                            int len,
                                            int* pad_bytes) {
  DCHECK_LE(kTurnChannelDataHeaderSize, len);
  // Both stun and turn had length at offset 2.
  int packet_size = base::NetToHost16(
      *reinterpret_cast<const uint16_t*>(data + kPacketLengthOffset));

  // Get packet type (STUN or TURN).
  uint16_t msg_type =
      base::NetToHost16(*reinterpret_cast<const uint16_t*>(data));

  *pad_bytes = 0;
  // Add heder length to packet length.
  if ((msg_type & 0xC000) == 0) {
    packet_size += kStunHeaderSize;
  } else {
    packet_size += kTurnChannelDataHeaderSize;
    // Calculate any padding if present.
    if (packet_size % 4)
      *pad_bytes = 4 - packet_size % 4;
  }
  return packet_size;
}

}  // namespace network