1 | /*
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2 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without modification,
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6 | * are permitted provided that the following conditions are met:
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7 | *
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8 | * 1. Redistributions of source code must retain the above copyright notice,
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9 | * this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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11 | * this list of conditions and the following disclaimer in the documentation
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12 | * and/or other materials provided with the distribution.
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13 | * 3. The name of the author may not be used to endorse or promote products
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14 | * derived from this software without specific prior written permission.
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15 | *
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16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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17 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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18 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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19 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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20 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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21 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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22 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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23 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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24 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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25 | * OF SUCH DAMAGE.
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26 | *
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27 | * This file is part of the lwIP TCP/IP stack.
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28 | *
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29 | * Author: Adam Dunkels <adam@sics.se>
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30 | *
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31 | */
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32 | #ifndef __LWIP_TCP_H__
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33 | #define __LWIP_TCP_H__
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34 |
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35 | #include "lwip/opt.h"
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36 |
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37 | #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
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38 |
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39 | #include "lwip/mem.h"
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40 | #include "lwip/pbuf.h"
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41 | #include "lwip/ip.h"
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42 | #include "lwip/icmp.h"
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43 | #include "lwip/err.h"
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44 |
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45 | #ifdef __cplusplus
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46 | extern "C" {
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47 | #endif
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48 |
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49 | struct tcp_pcb;
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50 |
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51 | /** Function prototype for tcp accept callback functions. Called when a new
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52 | * connection can be accepted on a listening pcb.
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53 | *
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54 | * @param arg Additional argument to pass to the callback function (@see tcp_arg())
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55 | * @param newpcb The new connection pcb
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56 | * @param err An error code if there has been an error accepting.
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57 | * Only return ERR_ABRT if you have called tcp_abort from within the
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58 | * callback function!
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59 | */
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60 | typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err);
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61 |
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62 | /** Function prototype for tcp receive callback functions. Called when data has
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63 | * been received.
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64 | *
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65 | * @param arg Additional argument to pass to the callback function (@see tcp_arg())
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66 | * @param tpcb The connection pcb which received data
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67 | * @param p The received data (or NULL when the connection has been closed!)
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68 | * @param err An error code if there has been an error receiving
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69 | * Only return ERR_ABRT if you have called tcp_abort from within the
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70 | * callback function!
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71 | */
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72 | typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb,
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73 | struct pbuf *p, err_t err);
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74 |
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75 | /** Function prototype for tcp sent callback functions. Called when sent data has
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76 | * been acknowledged by the remote side. Use it to free corresponding resources.
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77 | * This also means that the pcb has now space available to send new data.
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78 | *
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79 | * @param arg Additional argument to pass to the callback function (@see tcp_arg())
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80 | * @param tpcb The connection pcb for which data has been acknowledged
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81 | * @param len The amount of bytes acknowledged
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82 | * @return ERR_OK: try to send some data by calling tcp_output
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83 | * Only return ERR_ABRT if you have called tcp_abort from within the
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84 | * callback function!
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85 | */
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86 | typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb,
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87 | u16_t len);
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88 |
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89 | /** Function prototype for tcp poll callback functions. Called periodically as
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90 | * specified by @see tcp_poll.
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91 | *
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92 | * @param arg Additional argument to pass to the callback function (@see tcp_arg())
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93 | * @param tpcb tcp pcb
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94 | * @return ERR_OK: try to send some data by calling tcp_output
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95 | * Only return ERR_ABRT if you have called tcp_abort from within the
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96 | * callback function!
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97 | */
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98 | typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb);
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99 |
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100 | /** Function prototype for tcp error callback functions. Called when the pcb
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101 | * receives a RST or is unexpectedly closed for any other reason.
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102 | *
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103 | * @note The corresponding pcb is already freed when this callback is called!
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104 | *
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105 | * @param arg Additional argument to pass to the callback function (@see tcp_arg())
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106 | * @param err Error code to indicate why the pcb has been closed
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107 | * ERR_ABRT: aborted through tcp_abort or by a TCP timer
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108 | * ERR_RST: the connection was reset by the remote host
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109 | */
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110 | typedef void (*tcp_err_fn)(void *arg, err_t err);
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111 |
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112 | /** Function prototype for tcp connected callback functions. Called when a pcb
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113 | * is connected to the remote side after initiating a connection attempt by
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114 | * calling tcp_connect().
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115 | *
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116 | * @param arg Additional argument to pass to the callback function (@see tcp_arg())
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117 | * @param tpcb The connection pcb which is connected
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118 | * @param err An unused error code, always ERR_OK currently ;-) TODO!
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119 | * Only return ERR_ABRT if you have called tcp_abort from within the
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120 | * callback function!
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121 | *
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122 | * @note When a connection attempt fails, the error callback is currently called!
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123 | */
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124 | typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err);
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125 |
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126 | enum tcp_state {
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127 | CLOSED = 0,
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128 | LISTEN = 1,
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129 | SYN_SENT = 2,
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130 | SYN_RCVD = 3,
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131 | ESTABLISHED = 4,
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132 | FIN_WAIT_1 = 5,
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133 | FIN_WAIT_2 = 6,
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134 | CLOSE_WAIT = 7,
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135 | CLOSING = 8,
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136 | LAST_ACK = 9,
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137 | TIME_WAIT = 10
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138 | };
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139 |
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140 | #if LWIP_CALLBACK_API
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141 | /* Function to call when a listener has been connected.
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142 | * @param arg user-supplied argument (tcp_pcb.callback_arg)
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143 | * @param pcb a new tcp_pcb that now is connected
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144 | * @param err an error argument (TODO: that is current always ERR_OK?)
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145 | * @return ERR_OK: accept the new connection,
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146 | * any other err_t abortsthe new connection
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147 | */
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148 | #define DEF_ACCEPT_CALLBACK tcp_accept_fn accept;
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149 | #else /* LWIP_CALLBACK_API */
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150 | #define DEF_ACCEPT_CALLBACK
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151 | #endif /* LWIP_CALLBACK_API */
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152 |
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153 | /**
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154 | * members common to struct tcp_pcb and struct tcp_listen_pcb
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155 | */
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156 | #define TCP_PCB_COMMON(type) \
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157 | type *next; /* for the linked list */ \
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158 | void *callback_arg; \
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159 | /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
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160 | DEF_ACCEPT_CALLBACK \
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161 | enum tcp_state state; /* TCP state */ \
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162 | u8_t prio; \
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163 | /* ports are in host byte order */ \
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164 | u16_t local_port
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165 |
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166 |
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167 | /* the TCP protocol control block */
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168 | struct tcp_pcb {
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169 | /** common PCB members */
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170 | IP_PCB;
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171 | /** protocol specific PCB members */
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172 | TCP_PCB_COMMON(struct tcp_pcb);
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173 |
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174 | /* ports are in host byte order */
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175 | u16_t remote_port;
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176 |
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177 | u8_t flags;
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178 | #define TF_ACK_DELAY ((u8_t)0x01U) /* Delayed ACK. */
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179 | #define TF_ACK_NOW ((u8_t)0x02U) /* Immediate ACK. */
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180 | #define TF_INFR ((u8_t)0x04U) /* In fast recovery. */
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181 | #define TF_TIMESTAMP ((u8_t)0x08U) /* Timestamp option enabled */
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182 | #define TF_RXCLOSED ((u8_t)0x10U) /* rx closed by tcp_shutdown */
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183 | #define TF_FIN ((u8_t)0x20U) /* Connection was closed locally (FIN segment enqueued). */
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184 | #define TF_NODELAY ((u8_t)0x40U) /* Disable Nagle algorithm */
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185 | #define TF_NAGLEMEMERR ((u8_t)0x80U) /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
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186 |
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187 | /* the rest of the fields are in host byte order
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188 | as we have to do some math with them */
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189 |
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190 | /* Timers */
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191 | u8_t polltmr, pollinterval;
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192 | u8_t last_timer;
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193 | u32_t tmr;
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194 |
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195 | /* receiver variables */
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196 | u32_t rcv_nxt; /* next seqno expected */
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197 | u16_t rcv_wnd; /* receiver window available */
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198 | u16_t rcv_ann_wnd; /* receiver window to announce */
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199 | u32_t rcv_ann_right_edge; /* announced right edge of window */
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200 |
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201 | /* Retransmission timer. */
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202 | s16_t rtime;
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203 |
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204 | u16_t mss; /* maximum segment size */
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205 |
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206 | /* RTT (round trip time) estimation variables */
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207 | u32_t rttest; /* RTT estimate in 500ms ticks */
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208 | u32_t rtseq; /* sequence number being timed */
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209 | s16_t sa, sv; /* @todo document this */
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210 |
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211 | s16_t rto; /* retransmission time-out */
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212 | u8_t nrtx; /* number of retransmissions */
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213 |
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214 | /* fast retransmit/recovery */
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215 | u8_t dupacks;
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216 | u32_t lastack; /* Highest acknowledged seqno. */
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217 |
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218 | /* congestion avoidance/control variables */
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219 | u16_t cwnd;
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220 | u16_t ssthresh;
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221 |
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222 | /* sender variables */
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223 | u32_t snd_nxt; /* next new seqno to be sent */
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224 | u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last
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225 | window update. */
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226 | u32_t snd_lbb; /* Sequence number of next byte to be buffered. */
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227 | u16_t snd_wnd; /* sender window */
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228 | u16_t snd_wnd_max; /* the maximum sender window announced by the remote host */
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229 |
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230 | u16_t acked;
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231 |
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232 | u16_t snd_buf; /* Available buffer space for sending (in bytes). */
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233 | #define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3)
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234 | u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
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235 |
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236 | #if TCP_OVERSIZE
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237 | /* Extra bytes available at the end of the last pbuf in unsent. */
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238 | u16_t unsent_oversize;
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239 | #endif /* TCP_OVERSIZE */
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240 |
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241 | /* These are ordered by sequence number: */
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242 | struct tcp_seg *unsent; /* Unsent (queued) segments. */
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243 | struct tcp_seg *unacked; /* Sent but unacknowledged segments. */
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244 | #if TCP_QUEUE_OOSEQ
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245 | struct tcp_seg *ooseq; /* Received out of sequence segments. */
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246 | #endif /* TCP_QUEUE_OOSEQ */
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247 |
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248 | struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
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249 |
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250 | #if LWIP_CALLBACK_API
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251 | /* Function to be called when more send buffer space is available. */
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252 | tcp_sent_fn sent;
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253 | /* Function to be called when (in-sequence) data has arrived. */
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254 | tcp_recv_fn recv;
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255 | /* Function to be called when a connection has been set up. */
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256 | tcp_connected_fn connected;
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257 | /* Function which is called periodically. */
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258 | tcp_poll_fn poll;
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259 | /* Function to be called whenever a fatal error occurs. */
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260 | tcp_err_fn errf;
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261 | #endif /* LWIP_CALLBACK_API */
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262 |
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263 | #if LWIP_TCP_TIMESTAMPS
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264 | u32_t ts_lastacksent;
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265 | u32_t ts_recent;
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266 | #endif /* LWIP_TCP_TIMESTAMPS */
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267 |
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268 | /* idle time before KEEPALIVE is sent */
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269 | u32_t keep_idle;
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270 | #if LWIP_TCP_KEEPALIVE
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271 | u32_t keep_intvl;
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272 | u32_t keep_cnt;
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273 | #endif /* LWIP_TCP_KEEPALIVE */
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274 |
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275 | /* Persist timer counter */
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276 | u8_t persist_cnt;
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277 | /* Persist timer back-off */
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278 | u8_t persist_backoff;
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279 |
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280 | /* KEEPALIVE counter */
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281 | u8_t keep_cnt_sent;
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282 | };
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283 |
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284 | struct tcp_pcb_listen {
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285 | /* Common members of all PCB types */
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286 | IP_PCB;
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287 | /* Protocol specific PCB members */
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288 | TCP_PCB_COMMON(struct tcp_pcb_listen);
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289 |
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290 | #if TCP_LISTEN_BACKLOG
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291 | u8_t backlog;
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292 | u8_t accepts_pending;
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293 | #endif /* TCP_LISTEN_BACKLOG */
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294 | };
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295 |
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296 | #if LWIP_EVENT_API
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297 |
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298 | enum lwip_event {
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299 | LWIP_EVENT_ACCEPT,
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300 | LWIP_EVENT_SENT,
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301 | LWIP_EVENT_RECV,
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302 | LWIP_EVENT_CONNECTED,
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303 | LWIP_EVENT_POLL,
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304 | LWIP_EVENT_ERR
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305 | };
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306 |
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307 | err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
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308 | enum lwip_event,
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309 | struct pbuf *p,
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310 | u16_t size,
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311 | err_t err);
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312 |
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313 | #endif /* LWIP_EVENT_API */
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314 |
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315 | /* Application program's interface: */
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316 | struct tcp_pcb * tcp_new (void);
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317 |
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318 | void tcp_arg (struct tcp_pcb *pcb, void *arg);
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319 | void tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept);
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320 | void tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv);
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321 | void tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent);
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322 | void tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval);
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323 | void tcp_err (struct tcp_pcb *pcb, tcp_err_fn err);
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324 |
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325 | #define tcp_mss(pcb) (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12) : (pcb)->mss)
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326 | #define tcp_sndbuf(pcb) ((pcb)->snd_buf)
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327 | #define tcp_sndqueuelen(pcb) ((pcb)->snd_queuelen)
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328 | #define tcp_nagle_disable(pcb) ((pcb)->flags |= TF_NODELAY)
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329 | #define tcp_nagle_enable(pcb) ((pcb)->flags &= ~TF_NODELAY)
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330 | #define tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0)
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331 |
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332 | #if TCP_LISTEN_BACKLOG
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333 | #define tcp_accepted(pcb) do { \
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334 | LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \
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335 | (((struct tcp_pcb_listen *)(pcb))->accepts_pending--); } while(0)
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336 | #else /* TCP_LISTEN_BACKLOG */
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337 | #define tcp_accepted(pcb) LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", \
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338 | (pcb)->state == LISTEN)
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339 | #endif /* TCP_LISTEN_BACKLOG */
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340 |
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341 | void tcp_recved (struct tcp_pcb *pcb, u16_t len);
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342 | err_t tcp_bind (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
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343 | u16_t port);
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344 | err_t tcp_connect (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
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345 | u16_t port, tcp_connected_fn connected);
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346 |
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347 | struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
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348 | #define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
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349 |
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350 | void tcp_abort (struct tcp_pcb *pcb);
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351 | err_t tcp_close (struct tcp_pcb *pcb);
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352 | err_t tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx);
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353 |
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354 | /* Flags for "apiflags" parameter in tcp_write */
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355 | #define TCP_WRITE_FLAG_COPY 0x01
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356 | #define TCP_WRITE_FLAG_MORE 0x02
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357 |
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358 | err_t tcp_write (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
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359 | u8_t apiflags);
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360 |
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361 | void tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
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362 |
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363 | #define TCP_PRIO_MIN 1
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364 | #define TCP_PRIO_NORMAL 64
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365 | #define TCP_PRIO_MAX 127
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366 |
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367 | err_t tcp_output (struct tcp_pcb *pcb);
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368 |
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369 |
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370 | const char* tcp_debug_state_str(enum tcp_state s);
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371 |
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372 |
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373 | #ifdef __cplusplus
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374 | }
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375 | #endif
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376 |
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377 | #endif /* LWIP_TCP */
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378 |
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379 | #endif /* __LWIP_TCP_H__ */
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