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/* |
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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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/** |
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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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|
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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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|
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#if LWIP_TCP |
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|
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static struct tcp_pcb *echo_pcb; |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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LWIP_UNUSED_ARG(arg); |
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LWIP_UNUSED_ARG(err); |
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|
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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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|
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es = (struct echo_state *)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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|
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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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|
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LWIP_ASSERT("arg != NULL",arg != NULL); |
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es = (struct echo_state *)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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|
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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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|
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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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|
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LWIP_UNUSED_ARG(err); |
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|
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es = (struct echo_state *)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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|
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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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|
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es = (struct echo_state *)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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|
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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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|
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LWIP_UNUSED_ARG(len); |
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|
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es = (struct echo_state *)arg; |
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es->retries = 0; |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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#endif /* LWIP_TCP */ |