350 lines
7.4 KiB
C
350 lines
7.4 KiB
C
/*
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* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of and a contribution to the lwIP TCP/IP stack.
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*
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* Credits go to Adam Dunkels (and the current maintainers) of this software.
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*
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* Christiaan Simons rewrote this file to get a more stable echo example.
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*/
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/**
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* @file
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* TCP echo server example using raw API.
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*
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* Echos all bytes sent by connecting client,
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* and passively closes when client is done.
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*
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*/
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#include "lwip/debug.h"
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#include "lwip/stats.h"
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#include "lwip/tcp.h"
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static struct tcp_pcb *echo_pcb;
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enum echo_states
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{
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ES_NONE = 0,
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ES_ACCEPTED,
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ES_RECEIVED,
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ES_CLOSING
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};
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struct echo_state
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{
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u8_t state;
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u8_t retries;
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struct tcp_pcb *pcb;
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/* pbuf (chain) to recycle */
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struct pbuf *p;
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};
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err_t echo_accept(void *arg, struct tcp_pcb *newpcb, err_t err);
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err_t echo_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err);
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void echo_error(void *arg, err_t err);
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err_t echo_poll(void *arg, struct tcp_pcb *tpcb);
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err_t echo_sent(void *arg, struct tcp_pcb *tpcb, u16_t len);
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void echo_send(struct tcp_pcb *tpcb, struct echo_state *es);
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void echo_close(struct tcp_pcb *tpcb, struct echo_state *es);
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void
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echo_init(void)
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{
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echo_pcb = tcp_new();
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if (echo_pcb != NULL)
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{
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err_t err;
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err = tcp_bind(echo_pcb, IP_ADDR_ANY, 7);
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if (err == ERR_OK)
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{
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echo_pcb = tcp_listen(echo_pcb);
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tcp_accept(echo_pcb, echo_accept);
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}
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else
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{
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/* abort? output diagnostic? */
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}
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}
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else
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{
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/* abort? output diagnostic? */
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}
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}
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err_t
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echo_accept(void *arg, struct tcp_pcb *newpcb, err_t err)
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{
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err_t ret_err;
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struct echo_state *es;
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/* commonly observed practive to call tcp_setprio(), why? */
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tcp_setprio(newpcb, TCP_PRIO_MIN);
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es = mem_malloc(sizeof(struct echo_state));
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if (es != NULL)
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{
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es->state = ES_ACCEPTED;
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es->pcb = newpcb;
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es->retries = 0;
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es->p = NULL;
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/* pass newly allocated es to our callbacks */
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tcp_arg(newpcb, es);
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tcp_recv(newpcb, echo_recv);
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tcp_err(newpcb, echo_error);
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tcp_poll(newpcb, echo_poll, 0);
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ret_err = ERR_OK;
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}
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else
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{
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ret_err = ERR_MEM;
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}
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return ret_err;
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}
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err_t
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echo_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
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{
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struct echo_state *es;
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err_t ret_err;
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LWIP_ASSERT("arg != NULL",arg != NULL);
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es = arg;
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if (p == NULL)
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{
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/* remote host closed connection */
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es->state = ES_CLOSING;
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if(es->p == NULL)
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{
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/* we're done sending, close it */
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echo_close(tpcb, es);
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}
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else
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{
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/* we're not done yet */
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tcp_sent(tpcb, echo_sent);
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echo_send(tpcb, es);
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}
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ret_err = ERR_OK;
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}
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else if(err != ERR_OK)
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{
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/* cleanup, for unkown reason */
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if (p != NULL)
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{
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es->p = NULL;
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pbuf_free(p);
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}
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ret_err = err;
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}
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else if(es->state == ES_ACCEPTED)
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{
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/* first data chunk in p->payload */
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es->state = ES_RECEIVED;
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/* store reference to incoming pbuf (chain) */
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es->p = p;
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/* install send completion notifier */
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tcp_sent(tpcb, echo_sent);
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echo_send(tpcb, es);
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ret_err = ERR_OK;
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}
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else if (es->state == ES_RECEIVED)
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{
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/* read some more data */
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if(es->p == NULL)
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{
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es->p = p;
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tcp_sent(tpcb, echo_sent);
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echo_send(tpcb, es);
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}
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else
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{
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struct pbuf *ptr;
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/* chain pbufs to the end of what we recv'ed previously */
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ptr = es->p;
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pbuf_chain(ptr,p);
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}
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ret_err = ERR_OK;
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}
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else if(es->state == ES_CLOSING)
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{
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/* odd case, remote side closing twice, trash data */
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tcp_recved(tpcb, p->tot_len);
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es->p = NULL;
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pbuf_free(p);
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ret_err = ERR_OK;
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}
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else
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{
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/* unkown es->state, trash data */
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tcp_recved(tpcb, p->tot_len);
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es->p = NULL;
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pbuf_free(p);
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ret_err = ERR_OK;
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}
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return ret_err;
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}
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void
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echo_error(void *arg, err_t err)
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{
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struct echo_state *es;
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es = arg;
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if (es != NULL)
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{
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mem_free(es);
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}
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}
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err_t
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echo_poll(void *arg, struct tcp_pcb *tpcb)
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{
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err_t ret_err;
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struct echo_state *es;
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es = arg;
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if (es != NULL)
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{
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if (es->p != NULL)
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{
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/* there is a remaining pbuf (chain) */
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tcp_sent(tpcb, echo_sent);
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echo_send(tpcb, es);
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}
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else
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{
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/* no remaining pbuf (chain) */
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if(es->state == ES_CLOSING)
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{
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echo_close(tpcb, es);
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}
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}
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ret_err = ERR_OK;
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}
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else
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{
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/* nothing to be done */
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tcp_abort(tpcb);
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ret_err = ERR_ABRT;
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}
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return ret_err;
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}
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err_t
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echo_sent(void *arg, struct tcp_pcb *tpcb, u16_t len)
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{
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struct echo_state *es;
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es = arg;
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es->retries = 0;
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if(es->p != NULL)
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{
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/* still got pbufs to send */
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tcp_sent(tpcb, echo_sent);
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echo_send(tpcb, es);
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}
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else
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{
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/* no more pbufs to send */
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if(es->state == ES_CLOSING)
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{
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echo_close(tpcb, es);
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}
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}
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return ERR_OK;
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}
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void
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echo_send(struct tcp_pcb *tpcb, struct echo_state *es)
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{
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struct pbuf *ptr;
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err_t wr_err = ERR_OK;
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while ((wr_err == ERR_OK) &&
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(es->p != NULL) &&
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(es->p->len <= tcp_sndbuf(tpcb)))
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{
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ptr = es->p;
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/* enqueue data for transmission */
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wr_err = tcp_write(tpcb, ptr->payload, ptr->len, 1);
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if (wr_err == ERR_OK)
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{
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u16_t plen;
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u8_t freed;
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plen = ptr->len;
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/* continue with next pbuf in chain (if any) */
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es->p = ptr->next;
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if(es->p != NULL)
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{
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/* new reference! */
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pbuf_ref(es->p);
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}
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/* chop first pbuf from chain */
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do
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{
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/* try hard to free pbuf */
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freed = pbuf_free(ptr);
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}
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while(freed == 0);
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/* we can read more data now */
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tcp_recved(tpcb, plen);
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}
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else if(wr_err == ERR_MEM)
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{
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/* we are low on memory, try later / harder, defer to poll */
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es->p = ptr;
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}
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else
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{
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/* other problem ?? */
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}
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}
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}
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void
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echo_close(struct tcp_pcb *tpcb, struct echo_state *es)
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{
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tcp_arg(tpcb, NULL);
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tcp_sent(tpcb, NULL);
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tcp_recv(tpcb, NULL);
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tcp_err(tpcb, NULL);
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tcp_poll(tpcb, NULL, 0);
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if (es != NULL)
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{
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mem_free(es);
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}
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tcp_close(tpcb);
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}
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