lwip-contrib-mac/ports/unix/proj/minimal/echo.c

351 lines
7.5 KiB
C

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