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 and a contribution to the lwIP TCP/IP stack.
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28 | *
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29 | * Credits go to Adam Dunkels (and the current maintainers) of this software.
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30 | *
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31 | * Christiaan Simons rewrote this file to get a more stable echo example.
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32 | */
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33 |
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34 | /**
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35 | * @file
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36 | * TCP echo server example using raw API.
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37 | *
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38 | * Echos all bytes sent by connecting client,
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39 | * and passively closes when client is done.
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40 | *
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41 | */
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42 |
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43 | #include "lwip/opt.h"
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44 | #include "lwip/debug.h"
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45 | #include "lwip/stats.h"
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46 | #include "lwip/tcp.h"
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47 | #include "tcpecho_raw.h"
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48 |
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49 | #if LWIP_TCP && LWIP_CALLBACK_API
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50 |
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51 | static struct tcp_pcb *tcpecho_raw_pcb;
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52 |
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53 | enum tcpecho_raw_states
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54 | {
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55 | ES_NONE = 0,
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56 | ES_ACCEPTED,
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57 | ES_RECEIVED,
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58 | ES_CLOSING
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59 | };
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60 |
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61 | struct tcpecho_raw_state
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62 | {
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63 | u8_t state;
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64 | u8_t retries;
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65 | struct tcp_pcb *pcb;
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66 | /* pbuf (chain) to recycle */
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67 | struct pbuf *p;
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68 | };
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69 |
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70 | static void
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71 | tcpecho_raw_free(struct tcpecho_raw_state *es)
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72 | {
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73 | if (es != NULL) {
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74 | if (es->p) {
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75 | /* free the buffer chain if present */
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76 | pbuf_free(es->p);
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77 | }
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78 |
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79 | mem_free(es);
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80 | }
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81 | }
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82 |
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83 | static void
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84 | tcpecho_raw_close(struct tcp_pcb *tpcb, struct tcpecho_raw_state *es)
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85 | {
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86 | tcp_arg(tpcb, NULL);
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87 | tcp_sent(tpcb, NULL);
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88 | tcp_recv(tpcb, NULL);
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89 | tcp_err(tpcb, NULL);
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90 | tcp_poll(tpcb, NULL, 0);
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91 |
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92 | tcpecho_raw_free(es);
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93 |
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94 | tcp_close(tpcb);
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95 | }
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96 |
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97 | static void
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98 | tcpecho_raw_send(struct tcp_pcb *tpcb, struct tcpecho_raw_state *es)
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99 | {
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100 | struct pbuf *ptr;
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101 | err_t wr_err = ERR_OK;
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102 |
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103 | while ((wr_err == ERR_OK) &&
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104 | (es->p != NULL) &&
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105 | (es->p->len <= tcp_sndbuf(tpcb))) {
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106 | ptr = es->p;
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107 |
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108 | /* enqueue data for transmission */
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109 | wr_err = tcp_write(tpcb, ptr->payload, ptr->len, 1);
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110 | if (wr_err == ERR_OK) {
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111 | u16_t plen;
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112 |
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113 | plen = ptr->len;
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114 | /* continue with next pbuf in chain (if any) */
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115 | es->p = ptr->next;
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116 | if(es->p != NULL) {
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117 | /* new reference! */
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118 | pbuf_ref(es->p);
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119 | }
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120 | /* chop first pbuf from chain */
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121 | pbuf_free(ptr);
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122 | /* we can read more data now */
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123 | tcp_recved(tpcb, plen);
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124 | } else if(wr_err == ERR_MEM) {
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125 | /* we are low on memory, try later / harder, defer to poll */
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126 | es->p = ptr;
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127 | } else {
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128 | /* other problem ?? */
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129 | }
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130 | }
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131 | }
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132 |
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133 | static void
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134 | tcpecho_raw_error(void *arg, err_t err)
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135 | {
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136 | struct tcpecho_raw_state *es;
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137 |
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138 | LWIP_UNUSED_ARG(err);
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139 |
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140 | es = (struct tcpecho_raw_state *)arg;
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141 |
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142 | tcpecho_raw_free(es);
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143 | }
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144 |
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145 | static err_t
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146 | tcpecho_raw_poll(void *arg, struct tcp_pcb *tpcb)
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147 | {
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148 | err_t ret_err;
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149 | struct tcpecho_raw_state *es;
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150 |
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151 | es = (struct tcpecho_raw_state *)arg;
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152 | if (es != NULL) {
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153 | if (es->p != NULL) {
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154 | /* there is a remaining pbuf (chain) */
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155 | tcpecho_raw_send(tpcb, es);
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156 | } else {
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157 | /* no remaining pbuf (chain) */
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158 | if(es->state == ES_CLOSING) {
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159 | tcpecho_raw_close(tpcb, es);
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160 | }
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161 | }
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162 | ret_err = ERR_OK;
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163 | } else {
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164 | /* nothing to be done */
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165 | tcp_abort(tpcb);
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166 | ret_err = ERR_ABRT;
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167 | }
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168 | return ret_err;
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169 | }
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170 |
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171 | static err_t
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172 | tcpecho_raw_sent(void *arg, struct tcp_pcb *tpcb, u16_t len)
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173 | {
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174 | struct tcpecho_raw_state *es;
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175 |
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176 | LWIP_UNUSED_ARG(len);
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177 |
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178 | es = (struct tcpecho_raw_state *)arg;
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179 | es->retries = 0;
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180 |
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181 | if(es->p != NULL) {
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182 | /* still got pbufs to send */
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183 | tcp_sent(tpcb, tcpecho_raw_sent);
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184 | tcpecho_raw_send(tpcb, es);
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185 | } else {
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186 | /* no more pbufs to send */
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187 | if(es->state == ES_CLOSING) {
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188 | tcpecho_raw_close(tpcb, es);
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189 | }
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190 | }
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191 | return ERR_OK;
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192 | }
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193 |
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194 | static err_t
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195 | tcpecho_raw_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
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196 | {
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197 | struct tcpecho_raw_state *es;
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198 | err_t ret_err;
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199 |
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200 | LWIP_ASSERT("arg != NULL",arg != NULL);
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201 | es = (struct tcpecho_raw_state *)arg;
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202 | if (p == NULL) {
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203 | /* remote host closed connection */
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204 | es->state = ES_CLOSING;
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205 | if(es->p == NULL) {
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206 | /* we're done sending, close it */
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207 | tcpecho_raw_close(tpcb, es);
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208 | } else {
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209 | /* we're not done yet */
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210 | tcpecho_raw_send(tpcb, es);
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211 | }
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212 | ret_err = ERR_OK;
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213 | } else if(err != ERR_OK) {
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214 | /* cleanup, for unknown reason */
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215 | if (p != NULL) {
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216 | pbuf_free(p);
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217 | }
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218 | ret_err = err;
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219 | }
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220 | else if(es->state == ES_ACCEPTED) {
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221 | /* first data chunk in p->payload */
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222 | es->state = ES_RECEIVED;
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223 | /* store reference to incoming pbuf (chain) */
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224 | es->p = p;
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225 | tcpecho_raw_send(tpcb, es);
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226 | ret_err = ERR_OK;
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227 | } else if (es->state == ES_RECEIVED) {
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228 | /* read some more data */
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229 | if(es->p == NULL) {
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230 | es->p = p;
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231 | tcpecho_raw_send(tpcb, es);
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232 | } else {
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233 | struct pbuf *ptr;
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234 |
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235 | /* chain pbufs to the end of what we recv'ed previously */
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236 | ptr = es->p;
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237 | pbuf_cat(ptr,p);
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238 | }
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239 | ret_err = ERR_OK;
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240 | } else {
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241 | /* unkown es->state, trash data */
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242 | tcp_recved(tpcb, p->tot_len);
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243 | pbuf_free(p);
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244 | ret_err = ERR_OK;
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245 | }
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246 | return ret_err;
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247 | }
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248 |
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249 | static err_t
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250 | tcpecho_raw_accept(void *arg, struct tcp_pcb *newpcb, err_t err)
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251 | {
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252 | err_t ret_err;
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253 | struct tcpecho_raw_state *es;
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254 |
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255 | LWIP_UNUSED_ARG(arg);
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256 | if ((err != ERR_OK) || (newpcb == NULL)) {
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257 | return ERR_VAL;
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258 | }
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259 |
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260 | /* Unless this pcb should have NORMAL priority, set its priority now.
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261 | When running out of pcbs, low priority pcbs can be aborted to create
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262 | new pcbs of higher priority. */
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263 | tcp_setprio(newpcb, TCP_PRIO_MIN);
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264 |
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265 | es = (struct tcpecho_raw_state *)mem_malloc(sizeof(struct tcpecho_raw_state));
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266 | if (es != NULL) {
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267 | es->state = ES_ACCEPTED;
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268 | es->pcb = newpcb;
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269 | es->retries = 0;
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270 | es->p = NULL;
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271 | /* pass newly allocated es to our callbacks */
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272 | tcp_arg(newpcb, es);
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273 | tcp_recv(newpcb, tcpecho_raw_recv);
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274 | tcp_err(newpcb, tcpecho_raw_error);
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275 | tcp_poll(newpcb, tcpecho_raw_poll, 0);
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276 | tcp_sent(newpcb, tcpecho_raw_sent);
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277 | ret_err = ERR_OK;
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278 | } else {
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279 | ret_err = ERR_MEM;
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280 | }
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281 | return ret_err;
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282 | }
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283 |
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284 | void
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285 | tcpecho_raw_init(void)
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286 | {
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287 | tcpecho_raw_pcb = tcp_new_ip_type(IPADDR_TYPE_ANY);
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288 | if (tcpecho_raw_pcb != NULL) {
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289 | err_t err;
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290 |
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291 | err = tcp_bind(tcpecho_raw_pcb, IP_ANY_TYPE, 7);
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292 | if (err == ERR_OK) {
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293 | tcpecho_raw_pcb = tcp_listen(tcpecho_raw_pcb);
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294 | tcp_accept(tcpecho_raw_pcb, tcpecho_raw_accept);
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295 | } else {
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296 | /* abort? output diagnostic? */
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297 | }
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298 | } else {
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299 | /* abort? output diagnostic? */
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300 | }
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301 | }
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302 |
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303 | #endif /* LWIP_TCP && LWIP_CALLBACK_API */
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