1 /* 2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef WEBRTC_P2P_BASE_PSEUDOTCP_H_ 12 #define WEBRTC_P2P_BASE_PSEUDOTCP_H_ 13 14 #include <list> 15 16 #include "webrtc/base/basictypes.h" 17 #include "webrtc/base/stream.h" 18 19 namespace cricket { 20 21 ////////////////////////////////////////////////////////////////////// 22 // IPseudoTcpNotify 23 ////////////////////////////////////////////////////////////////////// 24 25 class PseudoTcp; 26 27 class IPseudoTcpNotify { 28 public: 29 // Notification of tcp events 30 virtual void OnTcpOpen(PseudoTcp* tcp) = 0; 31 virtual void OnTcpReadable(PseudoTcp* tcp) = 0; 32 virtual void OnTcpWriteable(PseudoTcp* tcp) = 0; 33 virtual void OnTcpClosed(PseudoTcp* tcp, uint32 error) = 0; 34 35 // Write the packet onto the network 36 enum WriteResult { WR_SUCCESS, WR_TOO_LARGE, WR_FAIL }; 37 virtual WriteResult TcpWritePacket(PseudoTcp* tcp, 38 const char* buffer, size_t len) = 0; 39 40 protected: ~IPseudoTcpNotify()41 virtual ~IPseudoTcpNotify() {} 42 }; 43 44 ////////////////////////////////////////////////////////////////////// 45 // PseudoTcp 46 ////////////////////////////////////////////////////////////////////// 47 48 class PseudoTcp { 49 public: 50 static uint32 Now(); 51 52 PseudoTcp(IPseudoTcpNotify* notify, uint32 conv); 53 virtual ~PseudoTcp(); 54 55 int Connect(); 56 int Recv(char* buffer, size_t len); 57 int Send(const char* buffer, size_t len); 58 void Close(bool force); 59 int GetError(); 60 61 enum TcpState { 62 TCP_LISTEN, TCP_SYN_SENT, TCP_SYN_RECEIVED, TCP_ESTABLISHED, TCP_CLOSED 63 }; State()64 TcpState State() const { return m_state; } 65 66 // Call this when the PMTU changes. 67 void NotifyMTU(uint16 mtu); 68 69 // Call this based on timeout value returned from GetNextClock. 70 // It's ok to call this too frequently. 71 void NotifyClock(uint32 now); 72 73 // Call this whenever a packet arrives. 74 // Returns true if the packet was processed successfully. 75 bool NotifyPacket(const char * buffer, size_t len); 76 77 // Call this to determine the next time NotifyClock should be called. 78 // Returns false if the socket is ready to be destroyed. 79 bool GetNextClock(uint32 now, long& timeout); 80 81 // Call these to get/set option values to tailor this PseudoTcp 82 // instance's behaviour for the kind of data it will carry. 83 // If an unrecognized option is set or got, an assertion will fire. 84 // 85 // Setting options for OPT_RCVBUF or OPT_SNDBUF after Connect() is called 86 // will result in an assertion. 87 enum Option { 88 OPT_NODELAY, // Whether to enable Nagle's algorithm (0 == off) 89 OPT_ACKDELAY, // The Delayed ACK timeout (0 == off). 90 OPT_RCVBUF, // Set the receive buffer size, in bytes. 91 OPT_SNDBUF, // Set the send buffer size, in bytes. 92 }; 93 void GetOption(Option opt, int* value); 94 void SetOption(Option opt, int value); 95 96 // Returns current congestion window in bytes. 97 uint32 GetCongestionWindow() const; 98 99 // Returns amount of data in bytes that has been sent, but haven't 100 // been acknowledged. 101 uint32 GetBytesInFlight() const; 102 103 // Returns number of bytes that were written in buffer and haven't 104 // been sent. 105 uint32 GetBytesBufferedNotSent() const; 106 107 // Returns current round-trip time estimate in milliseconds. 108 uint32 GetRoundTripTimeEstimateMs() const; 109 110 protected: 111 enum SendFlags { sfNone, sfDelayedAck, sfImmediateAck }; 112 113 struct Segment { 114 uint32 conv, seq, ack; 115 uint8 flags; 116 uint16 wnd; 117 const char * data; 118 uint32 len; 119 uint32 tsval, tsecr; 120 }; 121 122 struct SSegment { SSegmentSSegment123 SSegment(uint32 s, uint32 l, bool c) 124 : seq(s), len(l), /*tstamp(0),*/ xmit(0), bCtrl(c) { 125 } 126 uint32 seq, len; 127 //uint32 tstamp; 128 uint8 xmit; 129 bool bCtrl; 130 }; 131 typedef std::list<SSegment> SList; 132 133 struct RSegment { 134 uint32 seq, len; 135 }; 136 137 uint32 queue(const char* data, uint32 len, bool bCtrl); 138 139 // Creates a packet and submits it to the network. This method can either 140 // send payload or just an ACK packet. 141 // 142 // |seq| is the sequence number of this packet. 143 // |flags| is the flags for sending this packet. 144 // |offset| is the offset to read from |m_sbuf|. 145 // |len| is the number of bytes to read from |m_sbuf| as payload. If this 146 // value is 0 then this is an ACK packet, otherwise this packet has payload. 147 IPseudoTcpNotify::WriteResult packet(uint32 seq, uint8 flags, 148 uint32 offset, uint32 len); 149 bool parse(const uint8* buffer, uint32 size); 150 151 void attemptSend(SendFlags sflags = sfNone); 152 153 void closedown(uint32 err = 0); 154 155 bool clock_check(uint32 now, long& nTimeout); 156 157 bool process(Segment& seg); 158 bool transmit(const SList::iterator& seg, uint32 now); 159 160 void adjustMTU(); 161 162 protected: 163 // This method is used in test only to query receive buffer state. 164 bool isReceiveBufferFull() const; 165 166 // This method is only used in tests, to disable window scaling 167 // support for testing backward compatibility. 168 void disableWindowScale(); 169 170 private: 171 // Queue the connect message with TCP options. 172 void queueConnectMessage(); 173 174 // Parse TCP options in the header. 175 void parseOptions(const char* data, uint32 len); 176 177 // Apply a TCP option that has been read from the header. 178 void applyOption(char kind, const char* data, uint32 len); 179 180 // Apply window scale option. 181 void applyWindowScaleOption(uint8 scale_factor); 182 183 // Resize the send buffer with |new_size| in bytes. 184 void resizeSendBuffer(uint32 new_size); 185 186 // Resize the receive buffer with |new_size| in bytes. This call adjusts 187 // window scale factor |m_swnd_scale| accordingly. 188 void resizeReceiveBuffer(uint32 new_size); 189 190 IPseudoTcpNotify* m_notify; 191 enum Shutdown { SD_NONE, SD_GRACEFUL, SD_FORCEFUL } m_shutdown; 192 int m_error; 193 194 // TCB data 195 TcpState m_state; 196 uint32 m_conv; 197 bool m_bReadEnable, m_bWriteEnable, m_bOutgoing; 198 uint32 m_lasttraffic; 199 200 // Incoming data 201 typedef std::list<RSegment> RList; 202 RList m_rlist; 203 uint32 m_rbuf_len, m_rcv_nxt, m_rcv_wnd, m_lastrecv; 204 uint8 m_rwnd_scale; // Window scale factor. 205 rtc::FifoBuffer m_rbuf; 206 207 // Outgoing data 208 SList m_slist; 209 uint32 m_sbuf_len, m_snd_nxt, m_snd_wnd, m_lastsend, m_snd_una; 210 uint8 m_swnd_scale; // Window scale factor. 211 rtc::FifoBuffer m_sbuf; 212 213 // Maximum segment size, estimated protocol level, largest segment sent 214 uint32 m_mss, m_msslevel, m_largest, m_mtu_advise; 215 // Retransmit timer 216 uint32 m_rto_base; 217 218 // Timestamp tracking 219 uint32 m_ts_recent, m_ts_lastack; 220 221 // Round-trip calculation 222 uint32 m_rx_rttvar, m_rx_srtt, m_rx_rto; 223 224 // Congestion avoidance, Fast retransmit/recovery, Delayed ACKs 225 uint32 m_ssthresh, m_cwnd; 226 uint8 m_dup_acks; 227 uint32 m_recover; 228 uint32 m_t_ack; 229 230 // Configuration options 231 bool m_use_nagling; 232 uint32 m_ack_delay; 233 234 // This is used by unit tests to test backward compatibility of 235 // PseudoTcp implementations that don't support window scaling. 236 bool m_support_wnd_scale; 237 }; 238 239 } // namespace cricket 240 241 #endif // WEBRTC_P2P_BASE_PSEUDOTCP_H_ 242