ip6.c

嵌入式TCpip协议栈 开源代码

/*
 * 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: ip6.c,v 1.1 2001/12/12 10:00:59 adam Exp $
 */


/*-----------------------------------------------------------------------------------*/
/* ip.c
 *
 * This is the code for the IP layer for IPv6.
 *
 */   
/*-----------------------------------------------------------------------------------*/

#include "lwip/debug.h"

#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/ip.h"
#include "lwip/inet.h"
#include "lwip/netif.h"
#include "lwip/icmp.h"
#include "lwip/udp.h"
#include "lwip/tcp.h"

#include "lwip/stats.h"

#include "arch/perf.h"
/*-----------------------------------------------------------------------------------*/
/* ip_init:
 *
 * Initializes the IP layer.
 */
/*-----------------------------------------------------------------------------------*/
void
ip_init(void)
{
}
/*-----------------------------------------------------------------------------------*/
/* ip_route:
 *
 * Finds the appropriate network interface for a given IP address. It searches the
 * list of network interfaces linearly. A match is found if the masked IP address of
 * the network interface equals the masked IP address given to the function.
 */
/*-----------------------------------------------------------------------------------*/
struct netif *
ip_route(struct ip_addr *dest)
{
  struct netif *netif;
  
  for(netif = netif_list; netif != NULL; netif = netif->next) {
    if(ip_addr_maskcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
      return netif;
    }
  }

  return netif_default;
}
/*-----------------------------------------------------------------------------------*/
/* ip_forward:
 *
 * Forwards an IP packet. It finds an appropriate route for the packet, decrements
 * the TTL value of the packet, adjusts the checksum and outputs the packet on the
 * appropriate interface.
 */
/*-----------------------------------------------------------------------------------*/
static void
ip_forward(struct pbuf *p, struct ip_hdr *iphdr)
{
  struct netif *netif;
  
  PERF_START;
  
  if((netif = ip_route((struct ip_addr *)&(iphdr->dest))) == NULL) {

    DEBUGF(IP_DEBUG, ("ip_input: no forwarding route found for "));
#if IP_DEBUG
    ip_addr_debug_print(&(iphdr->dest));
#endif /* IP_DEBUG */
    DEBUGF(IP_DEBUG, ("\n"));
    pbuf_free(p);
    return;
  }
  /* Decrement TTL and send ICMP if ttl == 0. */
  if(--iphdr->hoplim == 0) {
    /* Don't send ICMP messages in response to ICMP messages */
    if(iphdr->nexthdr != IP_PROTO_ICMP) {
      icmp_time_exceeded(p, ICMP_TE_TTL);
    }
    pbuf_free(p);
    return;       
  }
  
  /* Incremental update of the IP checksum. */
  /*  if (iphdr->chksum >= htons(0xffff - 0x100)) {
    iphdr->chksum += htons(0x100) + 1;
  } else {
    iphdr->chksum += htons(0x100);
    }*/
  

  DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to "));
#if IP_DEBUG
  ip_addr_debug_print(&(iphdr->dest));
#endif /* IP_DEBUG */
  DEBUGF(IP_DEBUG, ("\n"));

#ifdef IP_STATS
  ++stats.ip.fw;
  ++stats.ip.xmit;
#endif /* IP_STATS */

  PERF_STOP("ip_forward");
  
  netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));
}
/*-----------------------------------------------------------------------------------*/
/* ip_input:
 *
 * This function is called by the network interface device driver when an IP packet is
 * received. The function does the basic checks of the IP header such as packet size
 * being at least larger than the header size etc. If the packet was not destined for
 * us, the packet is forwarded (using ip_forward). The IP checksum is always checked.
 *
 * Finally, the packet is sent to the upper layer protocol input function.
 */
/*-----------------------------------------------------------------------------------*/
void
ip_input(struct pbuf *p, struct netif *inp) {
  struct ip_hdr *iphdr;
  struct netif *netif;

  
  PERF_START;

#if IP_DEBUG
  ip_debug_print(p);
#endif /* IP_DEBUG */

  
#ifdef IP_STATS
  ++stats.ip.recv;
#endif /* IP_STATS */
  
  /* identify the IP header */
  iphdr = p->payload;

  
  if(iphdr->v != 6) {
    DEBUGF(IP_DEBUG, ("IP packet dropped due to bad version number\n"));
#if IP_DEBUG
    ip_debug_print(p);
#endif /* IP_DEBUG */
    pbuf_free(p);
#ifdef IP_STATS
    ++stats.ip.err;
    ++stats.ip.drop;
#endif /* IP_STATS */
    return;
  }
  
  /* is this packet for us? */
  for(netif = netif_list; netif != NULL; netif = netif->next) {
#if IP_DEBUG
    DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest "));
    ip_addr_debug_print(&(iphdr->dest));
    DEBUGF(IP_DEBUG, ("netif->ip_addr "));
    ip_addr_debug_print(&(netif->ip_addr));
    DEBUGF(IP_DEBUG, ("\n"));
#endif /* IP_DEBUG */
    if(ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr))) {
      break;
    }
  }

  
  if(netif == NULL) {
    /* packet not for us, route or discard */
#ifdef IP_FORWARD
    ip_forward(p, iphdr);
#endif
    pbuf_free(p);
    return;
  }

  pbuf_realloc(p, IP_HLEN + ntohs(iphdr->len));
  
  /* send to upper layers */
#if IP_DEBUG
  /*  DEBUGF("ip_input: \n");
  ip_debug_print(p);
  DEBUGF("ip_input: p->len %d p->tot_len %d\n", p->len, p->tot_len);*/
#endif /* IP_DEBUG */
   

  pbuf_header(p, -IP_HLEN);

  switch(iphdr->nexthdr) {
  case IP_PROTO_UDP:
    udp_input(p);
    break;
  case IP_PROTO_TCP:
    tcp_input(p);
    break;
  case IP_PROTO_ICMP:
    icmp_input(p, inp);
    break;
  default:
    /* send ICMP destination protocol unreachable */
    icmp_dest_unreach(p, ICMP_DUR_PROTO);
    pbuf_free(p);
    DEBUGF(IP_DEBUG, ("Unsupported transportation protocol %d\n",
		      iphdr->nexthdr));

#ifdef IP_STATS
    ++stats.ip.proterr;
    ++stats.ip.drop;
#endif /* IP_STATS */

  }
  PERF_STOP("ip_input");
}

/*-----------------------------------------------------------------------------------*/
/* ip_output_if:
 *
 * Sends an IP packet on a network interface. This function constructs the IP header
 * and calculates the IP header checksum. If the source IP address is NULL,
 * the IP address of the outgoing network interface is filled in as source address.
 */
/*-----------------------------------------------------------------------------------*/
err_t
ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
	     u8_t ttl,
	     u8_t proto, struct netif *netif)
{
  struct ip_hdr *iphdr;

  PERF_START;

  printf("len %d tot_len %d\n", p->len, p->tot_len);
  if(pbuf_header(p, IP_HLEN)) {
    DEBUGF(IP_DEBUG, ("ip_output: not enough room for IP header in pbuf\n"));
#ifdef IP_STATS
    ++stats.ip.err;
#endif /* IP_STATS */

    return ERR_BUF;
  }
  printf("len %d tot_len %d\n", p->len, p->tot_len);
  
  iphdr = p->payload;
  

  if(dest != IP_HDRINCL) {
    printf("!IP_HDRLINCL\n");
    iphdr->hoplim = ttl;
    iphdr->nexthdr = proto;
    iphdr->len = htons(p->tot_len - IP_HLEN);
    ip_addr_set(&(iphdr->dest), dest);

    iphdr->v = 6;

    if(ip_addr_isany(src)) {
      ip_addr_set(&(iphdr->src), &(netif->ip_addr));
    } else {
      ip_addr_set(&(iphdr->src), src);
    }
    
  } else {
    dest = &(iphdr->dest);
  }

#ifdef IP_STATS
  ++stats.ip.xmit;
#endif /* IP_STATS */

  DEBUGF(IP_DEBUG, ("ip_output_if: %c%c (len %d)\n", netif->name[0], netif->name[1], p->tot_len));
#if IP_DEBUG
  ip_debug_print(p);
#endif /* IP_DEBUG */

  PERF_STOP("ip_output_if");
  return netif->output(netif, p, dest);  
}
/*-----------------------------------------------------------------------------------*/
/* ip_output:
 *
 * Simple interface to ip_output_if. It finds the outgoing network interface and
 * calls upon ip_output_if to do the actual work.
 */
/*-----------------------------------------------------------------------------------*/
err_t
ip_output(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
	  u8_t ttl, u8_t proto)
{
  struct netif *netif;
  if((netif = ip_route(dest)) == NULL) {
    DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%lx\n", dest->addr));
#ifdef IP_STATS
    ++stats.ip.rterr;
#endif /* IP_STATS */
    return ERR_RTE;
  }

  return ip_output_if(p, src, dest, ttl, proto, netif);
}
/*-----------------------------------------------------------------------------------*/
#if IP_DEBUG
void
ip_debug_print(struct pbuf *p)
{
  struct ip_hdr *iphdr = p->payload;
  char *payload;

  payload = (char *)iphdr + IP_HLEN;
  
  DEBUGF(IP_DEBUG, ("IP header:\n"));
  DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  DEBUGF(IP_DEBUG, ("|%2d |  %x%x  |      %x%x           | (v, traffic class, flow label)\n",
		    iphdr->v,
		    iphdr->tclass1, iphdr->tclass2,
		    iphdr->flow1, iphdr->flow2));
  DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  DEBUGF(IP_DEBUG, ("|    %5d      | %2d  |  %2d   | (len, nexthdr, hoplim)\n",
		    ntohs(iphdr->len),
		    iphdr->nexthdr,
		    iphdr->hoplim));
  DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",
		    ntohl(iphdr->src.addr[0]) >> 16 & 0xffff,
		    ntohl(iphdr->src.addr[0]) & 0xffff));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",
		    ntohl(iphdr->src.addr[1]) >> 16 & 0xffff,
		    ntohl(iphdr->src.addr[1]) & 0xffff));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",
		    ntohl(iphdr->src.addr[2]) >> 16 & 0xffff,
		    ntohl(iphdr->src.addr[2]) & 0xffff));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",
		    ntohl(iphdr->src.addr[3]) >> 16 & 0xffff,
		    ntohl(iphdr->src.addr[3]) & 0xffff));
  DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",
		    ntohl(iphdr->dest.addr[0]) >> 16 & 0xffff,
		    ntohl(iphdr->dest.addr[0]) & 0xffff));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",
		    ntohl(iphdr->dest.addr[1]) >> 16 & 0xffff,
		    ntohl(iphdr->dest.addr[1]) & 0xffff));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",
		    ntohl(iphdr->dest.addr[2]) >> 16 & 0xffff,
		    ntohl(iphdr->dest.addr[2]) & 0xffff));
  DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",
		    ntohl(iphdr->dest.addr[3]) >> 16 & 0xffff,
		    ntohl(iphdr->dest.addr[3]) & 0xffff));
  DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
}
#endif /* IP_DEBUG */
/*-----------------------------------------------------------------------------------*/