tcp.c

lwip在ucos上的移植源码

/*
 * Copyright (c) 2001, 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. Neither the name of the Institute nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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 the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <[e-mail]>
 *
 * $Id: tcp.c,v 1.1 2003/05/21 10:37:40 chenyu Exp $
 */

/*-----------------------------------------------------------------------------------*/
/* tcp.c
 *
 * This file contains common functions for the TCP implementation, such as functinos
 * for manipulating the data structures and the TCP timer functions. TCP functions
 * related to input and output is found in tcp_input.c and tcp_output.c respectively.
 *
 */
/*-----------------------------------------------------------------------------------*/

#include "lwip/debug.h"

#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/memp.h"

#include "lwip/tcp.h"

/* Incremented every coarse grained timer shot
   (typically every 500 ms, determined by TCP_COARSE_TIMEOUT). */
u32_t tcp_ticks;
const u8_t tcp_backoff[13] =
    { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };

/* The TCP PCB lists. */
struct tcp_pcb_listen *tcp_listen_pcbs;  /* List of all TCP PCBs in LISTEN state. */
struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
				 state in which they accept or send
				 data. */
struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */

struct tcp_pcb *tcp_tmp_pcb;

#define MIN(x,y) (x) < (y)? (x): (y)

#if MEMP_RECLAIM
static u8_t tcp_memp_reclaim(void *arg, memp_t type);
#endif
#if MEM_RECLAIM
static mem_size_t tcp_mem_reclaim(void *arg, mem_size_t size);
#endif

static u8_t tcp_timer;

/*-----------------------------------------------------------------------------------*/
/*
 * tcp_init():
 *
 * Initializes the TCP layer.
 */
/*-----------------------------------------------------------------------------------*/
void
tcp_init(void)
{
  /* Clear globals. */
  tcp_listen_pcbs = NULL;
  tcp_active_pcbs = NULL;
  tcp_tw_pcbs = NULL;
  tcp_tmp_pcb = NULL;
  
  /* Register memory reclaim function */
#if MEM_RECLAIM
  mem_register_reclaim((mem_reclaim_func)tcp_mem_reclaim, NULL);
#endif /* MEM_RECLAIM */

#if MEMP_RECLAIM
  memp_register_reclaim(MEMP_PBUF, (memp_reclaim_func)tcp_memp_reclaim, NULL);
  memp_register_reclaim(MEMP_TCP_SEG, (memp_reclaim_func)tcp_memp_reclaim, NULL);
  memp_register_reclaim(MEMP_TCP_PCB, (memp_reclaim_func)tcp_memp_reclaim, NULL);
#endif /* MEMP_RECLAIM */

  /* initialize timer */
  tcp_ticks = 0;
  tcp_timer = 0;
  
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_tmr():
 *
 * Called periodically to dispatch TCP timers.
 *
 */
/*-----------------------------------------------------------------------------------*/
void
tcp_tmr()
{
  ++tcp_timer;
  if(tcp_timer == 10) {
    tcp_timer = 0;
  }
  
  if(tcp_timer & 1) {
    /* Call tcp_fasttmr() every 200 ms, i.e., every other timer
       tcp_tmr() is called. */
    tcp_fasttmr();
  }
  if(tcp_timer == 0 || tcp_timer == 5) {
    /* Call tcp_slowtmr() every 500 ms, i.e., every fifth timer
       tcp_tmr() is called. */
    tcp_slowtmr();
  }
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_close():
 *
 * Closes the connection held by the PCB.
 *
 */
/*-----------------------------------------------------------------------------------*/
err_t
tcp_close(struct tcp_pcb *pcb)
{
  err_t err;

#if TCP_DEBUG
  DEBUGF(TCP_DEBUG, ("tcp_close: closing in state "));
  tcp_debug_print_state(pcb->state);
  DEBUGF(TCP_DEBUG, ("\n"));
#endif /* TCP_DEBUG */
  switch(pcb->state) {
  case LISTEN:
    err = ERR_OK;
    tcp_pcb_remove((struct tcp_pcb **)&tcp_listen_pcbs, pcb);
    memp_free(MEMP_TCP_PCB_LISTEN, pcb);
    pcb = NULL;
    break;
  case SYN_SENT:
    err = ERR_OK;
    tcp_pcb_remove(&tcp_active_pcbs, pcb);
    memp_free(MEMP_TCP_PCB, pcb);
    pcb = NULL;
    break;
  case SYN_RCVD:
    err = tcp_send_ctrl(pcb, TCP_FIN);
    if(err == ERR_OK) {
      pcb->state = FIN_WAIT_1;
    }
    break;
  case ESTABLISHED:
    err = tcp_send_ctrl(pcb, TCP_FIN);
    if(err == ERR_OK) {
      pcb->state = FIN_WAIT_1;
    }
    break;
  case CLOSE_WAIT:
    err = tcp_send_ctrl(pcb, TCP_FIN);
    if(err == ERR_OK) {
      pcb->state = LAST_ACK;
    }
    break;
  default:
    /* Has already been closed, do nothing. */
    err = ERR_OK;
    pcb = NULL;
    break;
  }

  if(pcb != NULL && err == ERR_OK) {
    err = tcp_output(pcb);
  }
  return err;
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_abort()
 *
 * Aborts a connection by sending a RST to the remote host and deletes
 * the local protocol control block. This is done when a connection is
 * killed because of shortage of memory.
 *
 */
/*-----------------------------------------------------------------------------------*/
void
tcp_abort(struct tcp_pcb *pcb)
{
  u32_t seqno, ackno;
  u16_t remote_port, local_port;
  struct ip_addr remote_ip, local_ip;
  void (* errf)(void *arg, err_t err);
  void *errf_arg;

  
  /* Figure out on which TCP PCB list we are, and remove us. If we
     are in an active state, call the receive function associated with
     the PCB with a NULL argument, and send an RST to the remote end. */
  if(pcb->state == TIME_WAIT) {
    tcp_pcb_remove(&tcp_tw_pcbs, pcb);
    memp_free(MEMP_TCP_PCB, pcb);
  } else if(pcb->state == LISTEN) {
    tcp_pcb_remove((struct tcp_pcb **)&tcp_listen_pcbs, pcb);
    memp_free(MEMP_TCP_PCB_LISTEN, pcb);
  } else {
    seqno = pcb->snd_nxt;
    ackno = pcb->rcv_nxt;
    ip_addr_set(&local_ip, &(pcb->local_ip));
    ip_addr_set(&remote_ip, &(pcb->remote_ip));
    local_port = pcb->local_port;
    remote_port = pcb->remote_port;
    errf = pcb->errf;
    errf_arg = pcb->callback_arg;
    tcp_pcb_remove(&tcp_active_pcbs, pcb);
    memp_free(MEMP_TCP_PCB, pcb);
    if(errf != NULL) {
      errf(errf_arg, ERR_ABRT);
    }
    DEBUGF(TCP_RST_DEBUG, ("tcp_abort: sending RST\n"));
    tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
  }
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_bind():
 *
 * Binds the connection to a local portnumber and IP address. If the
 * IP address is not given (i.e., ipaddr == NULL), the IP address of
 * the outgoing network interface is used instead.
 *
 */
/*-----------------------------------------------------------------------------------*/
err_t
tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port)
{
  struct tcp_pcb *cpcb;

  /* Check if the address already is in use. */
  for(cpcb = (struct tcp_pcb *)tcp_listen_pcbs;
      cpcb != NULL; cpcb = cpcb->next) {
    if(cpcb->local_port == port) {
      if(ip_addr_isany(&(cpcb->local_ip)) ||
	 ip_addr_isany(ipaddr) ||
	 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
	return ERR_USE;
      }
    }
  }
  for(cpcb = tcp_active_pcbs;
      cpcb != NULL; cpcb = cpcb->next) {
    if(cpcb->local_port == port) {
      if(ip_addr_isany(&(cpcb->local_ip)) ||
	 ip_addr_isany(ipaddr) ||
	 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
	return ERR_USE;
      }
    }
  }
  if(!ip_addr_isany(ipaddr)) {
    pcb->local_ip = *ipaddr;
  }
  pcb->local_port = port;
  DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %d\n", port));
  return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_listen():
 *
 * Set the state of the connection to be LISTEN, which means that it
 * is able to accept incoming connections. The protocol control block
 * is reallocated in order to consume less memory. Setting the
 * connection to LISTEN is an irreversible process.
 *
 */
/*-----------------------------------------------------------------------------------*/
struct tcp_pcb *
tcp_listen(struct tcp_pcb *pcb)
{
  pcb->state = LISTEN;
  pcb = memp_realloc(MEMP_TCP_PCB, MEMP_TCP_PCB_LISTEN, pcb);
  if(pcb == NULL) {
    return NULL;
  }
  TCP_REG((struct tcp_pcb **)&tcp_listen_pcbs, pcb);
  return pcb;
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_recved():
 *
 * This function should be called by the application when it has
 * processed the data. The purpose is to advertise a larger window
 * when the data has been processed.
 *
 */
/*-----------------------------------------------------------------------------------*/
void
tcp_recved(struct tcp_pcb *pcb, u16_t len)
{
  pcb->rcv_wnd += len;
  if(pcb->rcv_wnd > TCP_WND) {
    pcb->rcv_wnd = TCP_WND;
  }
  if(!(pcb->flags & TF_ACK_DELAY) ||
     !(pcb->flags & TF_ACK_NOW)) {
    tcp_ack(pcb);
  }
  DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %d bytes, wnd %u (%u).\n",
		     len, pcb->rcv_wnd, TCP_WND - pcb->rcv_wnd));
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_new_port():
 *
 * A nastly hack featuring 'goto' statements that allocates a
 * new TCP local port.
 */
/*-----------------------------------------------------------------------------------*/
static u16_t
tcp_new_port(void)
{
  struct tcp_pcb *pcb;
  static u16_t port = 4096;
  
 again:
  if(++port > 0x7fff) {
    port = 4096;
  }
  
  for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
    if(pcb->local_port == port) {
      goto again;
    }
  }
  for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
    if(pcb->local_port == port) {
      goto again;
    }
  }
  for(pcb = (struct tcp_pcb *)tcp_listen_pcbs; pcb != NULL; pcb = pcb->next) {
    if(pcb->local_port == port) {
      goto again;
    }
  }
  return port;
}
/*-----------------------------------------------------------------------------------*/
/*
 * tcp_connect():
 *
 * Connects to another host. The function given as the "connected"
 * argument will be called when the connection has been established.
 *
 */
/*-----------------------------------------------------------------------------------*/
err_t
tcp_connect(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port,
	    err_t (* connected)(void *arg, struct tcp_pcb *tpcb, err_t err))
{
  u32_t optdata;
  err_t ret;
  u32_t iss;