| /* |
| * Copyright 2013 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. |
| */ |
| |
| #include "p2p/base/async_stun_tcp_socket.h" |
| |
| #include <errno.h> |
| #include <stdint.h> |
| #include <string.h> |
| |
| #include "api/transport/stun.h" |
| #include "rtc_base/byte_order.h" |
| #include "rtc_base/checks.h" |
| #include "rtc_base/network/sent_packet.h" |
| #include "rtc_base/third_party/sigslot/sigslot.h" |
| #include "rtc_base/time_utils.h" |
| |
| namespace cricket { |
| |
| static const size_t kMaxPacketSize = 64 * 1024; |
| |
| typedef uint16_t PacketLength; |
| static const size_t kPacketLenSize = sizeof(PacketLength); |
| static const size_t kPacketLenOffset = 2; |
| static const size_t kBufSize = kMaxPacketSize + kStunHeaderSize; |
| static const size_t kTurnChannelDataHdrSize = 4; |
| |
| inline bool IsStunMessage(uint16_t msg_type) { |
| // The first two bits of a channel data message are 0b01. |
| return (msg_type & 0xC000) ? false : true; |
| } |
| |
| // AsyncStunTCPSocket |
| // Binds and connects `socket` and creates AsyncTCPSocket for |
| // it. Takes ownership of `socket`. Returns NULL if bind() or |
| // connect() fail (`socket` is destroyed in that case). |
| AsyncStunTCPSocket* AsyncStunTCPSocket::Create( |
| rtc::Socket* socket, |
| const rtc::SocketAddress& bind_address, |
| const rtc::SocketAddress& remote_address) { |
| return new AsyncStunTCPSocket( |
| AsyncTCPSocketBase::ConnectSocket(socket, bind_address, remote_address)); |
| } |
| |
| AsyncStunTCPSocket::AsyncStunTCPSocket(rtc::Socket* socket) |
| : rtc::AsyncTCPSocketBase(socket, /*listen=*/false, kBufSize) {} |
| |
| int AsyncStunTCPSocket::Send(const void* pv, |
| size_t cb, |
| const rtc::PacketOptions& options) { |
| if (cb > kBufSize || cb < kPacketLenSize + kPacketLenOffset) { |
| SetError(EMSGSIZE); |
| return -1; |
| } |
| |
| // If we are blocking on send, then silently drop this packet |
| if (!IsOutBufferEmpty()) |
| return static_cast<int>(cb); |
| |
| int pad_bytes; |
| size_t expected_pkt_len = GetExpectedLength(pv, cb, &pad_bytes); |
| |
| // Accepts only complete STUN/ChannelData packets. |
| if (cb != expected_pkt_len) |
| return -1; |
| |
| AppendToOutBuffer(pv, cb); |
| |
| RTC_DCHECK(pad_bytes < 4); |
| char padding[4] = {0}; |
| AppendToOutBuffer(padding, pad_bytes); |
| |
| int res = FlushOutBuffer(); |
| if (res <= 0) { |
| // drop packet if we made no progress |
| ClearOutBuffer(); |
| return res; |
| } |
| |
| rtc::SentPacket sent_packet(options.packet_id, rtc::TimeMillis()); |
| SignalSentPacket(this, sent_packet); |
| |
| // We claim to have sent the whole thing, even if we only sent partial |
| return static_cast<int>(cb); |
| } |
| |
| void AsyncStunTCPSocket::ProcessInput(char* data, size_t* len) { |
| rtc::SocketAddress remote_addr(GetRemoteAddress()); |
| // STUN packet - First 4 bytes. Total header size is 20 bytes. |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // |0 0| STUN Message Type | Message Length | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| // TURN ChannelData |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // | Channel Number | Length | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| while (true) { |
| // We need at least 4 bytes to read the STUN or ChannelData packet length. |
| if (*len < kPacketLenOffset + kPacketLenSize) |
| return; |
| |
| int pad_bytes; |
| size_t expected_pkt_len = GetExpectedLength(data, *len, &pad_bytes); |
| size_t actual_length = expected_pkt_len + pad_bytes; |
| |
| if (*len < actual_length) { |
| return; |
| } |
| |
| SignalReadPacket(this, data, expected_pkt_len, remote_addr, |
| rtc::TimeMicros()); |
| |
| *len -= actual_length; |
| if (*len > 0) { |
| memmove(data, data + actual_length, *len); |
| } |
| } |
| } |
| |
| void AsyncStunTCPSocket::HandleIncomingConnection(rtc::Socket* socket) { |
| SignalNewConnection(this, new AsyncStunTCPSocket(socket)); |
| } |
| |
| size_t AsyncStunTCPSocket::GetExpectedLength(const void* data, |
| size_t len, |
| int* pad_bytes) { |
| *pad_bytes = 0; |
| PacketLength pkt_len = |
| rtc::GetBE16(static_cast<const char*>(data) + kPacketLenOffset); |
| size_t expected_pkt_len; |
| uint16_t msg_type = rtc::GetBE16(data); |
| if (IsStunMessage(msg_type)) { |
| // STUN message. |
| expected_pkt_len = kStunHeaderSize + pkt_len; |
| } else { |
| // TURN ChannelData message. |
| expected_pkt_len = kTurnChannelDataHdrSize + pkt_len; |
| // From RFC 5766 section 11.5 |
| // Over TCP and TLS-over-TCP, the ChannelData message MUST be padded to |
| // a multiple of four bytes in order to ensure the alignment of |
| // subsequent messages. The padding is not reflected in the length |
| // field of the ChannelData message, so the actual size of a ChannelData |
| // message (including padding) is (4 + Length) rounded up to the nearest |
| // multiple of 4. Over UDP, the padding is not required but MAY be |
| // included. |
| if (expected_pkt_len % 4) |
| *pad_bytes = 4 - (expected_pkt_len % 4); |
| } |
| return expected_pkt_len; |
| } |
| |
| } // namespace cricket |