1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/*
* libjingle
* Copyright 2004--2005, Google Inc.
*
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#ifndef __PSEUDOTCP_H__
#define __PSEUDOTCP_H__
#include <list>
#include "talk/base/basictypes.h"
namespace cricket {
//////////////////////////////////////////////////////////////////////
// IPseudoTcpNotify
//////////////////////////////////////////////////////////////////////
class PseudoTcp;
class IPseudoTcpNotify {
public:
// Notification of tcp events
virtual void OnTcpOpen(PseudoTcp * tcp) = 0;
virtual void OnTcpReadable(PseudoTcp * tcp) = 0;
virtual void OnTcpWriteable(PseudoTcp * tcp) = 0;
virtual void OnTcpClosed(PseudoTcp * tcp, uint32 nError) = 0;
// Write the packet onto the network
enum WriteResult { WR_SUCCESS, WR_TOO_LARGE, WR_FAIL };
virtual WriteResult TcpWritePacket(PseudoTcp * tcp, const char * buffer, size_t len) = 0;
};
//////////////////////////////////////////////////////////////////////
// PseudoTcp
//////////////////////////////////////////////////////////////////////
class PseudoTcp {
public:
static uint32 Now();
PseudoTcp(IPseudoTcpNotify * notify, uint32 conv);
virtual ~PseudoTcp();
int Connect();
int Recv(char * buffer, size_t len);
int Send(const char * buffer, size_t len);
void Close(bool force);
int GetError();
enum TcpState { TCP_LISTEN, TCP_SYN_SENT, TCP_SYN_RECEIVED, TCP_ESTABLISHED, TCP_CLOSED };
TcpState State() const { return m_state; }
// Call this when the PMTU changes.
void NotifyMTU(uint16 mtu);
// Call this based on timeout value returned from GetNextClock.
// It's ok to call this too frequently.
void NotifyClock(uint32 now);
// Call this whenever a packet arrives.
// Returns true if the packet was processed successfully.
bool NotifyPacket(const char * buffer, size_t len);
// Call this to determine the next time NotifyClock should be called.
// Returns false if the socket is ready to be destroyed.
bool GetNextClock(uint32 now, long& timeout);
protected:
enum SendFlags { sfNone, sfDelayedAck, sfImmediateAck };
enum {
// Note: can't go as high as 1024 * 64, because of uint16 precision
kRcvBufSize = 1024 * 60,
// Note: send buffer should be larger to make sure we can always fill the
// receiver window
kSndBufSize = 1024 * 90
};
struct Segment {
uint32 conv, seq, ack;
uint8 flags;
uint16 wnd;
const char * data;
uint32 len;
uint32 tsval, tsecr;
};
struct SSegment {
uint32 seq, len;
//uint32 tstamp;
uint8 xmit;
bool bCtrl;
SSegment(uint32 s, uint32 l, bool c) : seq(s), len(l), /*tstamp(0),*/ xmit(0), bCtrl(c) { }
};
typedef std::list<SSegment> SList;
struct RSegment {
uint32 seq, len;
};
uint32 queue(const char * data, uint32 len, bool bCtrl);
IPseudoTcpNotify::WriteResult packet(uint32 seq, uint8 flags, const char * data, uint32 len);
bool parse(const uint8 * buffer, uint32 size);
void attemptSend(SendFlags sflags = sfNone);
void closedown(uint32 err = 0);
bool clock_check(uint32 now, long& nTimeout);
bool process(Segment& seg);
bool transmit(const SList::iterator& seg, uint32 now);
void adjustMTU();
private:
IPseudoTcpNotify * m_notify;
enum Shutdown { SD_NONE, SD_GRACEFUL, SD_FORCEFUL } m_shutdown;
int m_error;
// TCB data
TcpState m_state;
uint32 m_conv;
bool m_bReadEnable, m_bWriteEnable, m_bOutgoing;
uint32 m_lasttraffic;
// Incoming data
typedef std::list<RSegment> RList;
RList m_rlist;
char m_rbuf[kRcvBufSize];
uint32 m_rcv_nxt, m_rcv_wnd, m_rlen, m_lastrecv;
// Outgoing data
SList m_slist;
char m_sbuf[kSndBufSize];
uint32 m_snd_nxt, m_snd_wnd, m_slen, m_lastsend, m_snd_una;
// Maximum segment size, estimated protocol level, largest segment sent
uint32 m_mss, m_msslevel, m_largest, m_mtu_advise;
// Retransmit timer
uint32 m_rto_base;
// Timestamp tracking
uint32 m_ts_recent, m_ts_lastack;
// Round-trip calculation
uint32 m_rx_rttvar, m_rx_srtt, m_rx_rto;
// Congestion avoidance, Fast retransmit/recovery, Delayed ACKs
uint32 m_ssthresh, m_cwnd;
uint8 m_dup_acks;
uint32 m_recover;
uint32 m_t_ack;
};
//////////////////////////////////////////////////////////////////////
} // namespace cricket
#endif // __PSEUDOTCP_H__
|
