/* * 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 the lwIP TCP/IP stack. * * Author: Adam Dunkels <adam@sics.se> * *//* ip.c * * This is the code for the IP layer for IPv6. * */#include "lwip/opt.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. */voidip_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_netcmp(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 voidip_forward(struct pbuf *p, struct ip_hdr *iphdr){  struct netif *netif;  PERF_START;  if ((netif = ip_route((struct ip_addr *)&(iphdr->dest))) == NULL) {    LWIP_DEBUGF(IP_DEBUG, ("ip_input: no forwarding route found for "));#if IP_DEBUG    ip_addr_debug_print(IP_DEBUG, &(iphdr->dest));#endif /* IP_DEBUG */    LWIP_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);    }*/  LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to "));#if IP_DEBUG  ip_addr_debug_print(IP_DEBUG, &(iphdr->dest));#endif /* IP_DEBUG */  LWIP_DEBUGF(IP_DEBUG, ("\n"));#ifdef IP_STATS  ++lwip_stats.ip.fw;  ++lwip_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. */voidip_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  ++lwip_stats.ip.recv;#endif /* IP_STATS */  /* identify the IP header */  iphdr = p->payload;  if (iphdr->v != 6) {    LWIP_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    ++lwip_stats.ip.err;    ++lwip_stats.ip.drop;#endif /* IP_STATS */    return;  }  /* is this packet for us? */  for(netif = netif_list; netif != NULL; netif = netif->next) {#if IP_DEBUG    LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest "));    ip_addr_debug_print(IP_DEBUG, &(iphdr->dest));    LWIP_DEBUGF(IP_DEBUG, ("netif->ip_addr "));    ip_addr_debug_print(IP_DEBUG, &(netif->ip_addr));    LWIP_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  /*  LWIP_DEBUGF("ip_input: \n");  ip_debug_print(p);  LWIP_DEBUGF("ip_input: p->len %u p->tot_len %u\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);    LWIP_DEBUGF(IP_DEBUG, ("Unsupported transport protocol %u\n",          iphdr->nexthdr));#ifdef IP_STATS    ++lwip_stats.ip.proterr;    ++lwip_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_tip_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 %u tot_len %u\n", p->len, p->tot_len);  if (pbuf_header(p, IP_HLEN)) {    LWIP_DEBUGF(IP_DEBUG, ("ip_output: not enough room for IP header in pbuf\n"));#ifdef IP_STATS    ++lwip_stats.ip.err;#endif /* IP_STATS */    return ERR_BUF;  }  printf("len %u tot_len %u\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  ++lwip_stats.ip.xmit;#endif /* IP_STATS */  LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c (len %u)\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_tip_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) {    LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%lx\n", dest->addr));#ifdef IP_STATS    ++lwip_stats.ip.rterr;#endif /* IP_STATS */    return ERR_RTE;  }  return ip_output_if (p, src, dest, ttl, proto, netif);}#if IP_DEBUGvoidip_debug_print(struct pbuf *p){  struct ip_hdr *iphdr = p->payload;  char *payload;  payload = (char *)iphdr + IP_HLEN;  LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));  LWIP_DEBUGF(IP_DEBUG, ("|%2d |  %x%x  |      %x%x           | (v, traffic class, flow label)\n",        iphdr->v,        iphdr->tclass1, iphdr->tclass2,        iphdr->flow1, iphdr->flow2));  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));  LWIP_DEBUGF(IP_DEBUG, ("|    %5u      | %2u  |  %2u   | (len, nexthdr, hoplim)\n",        ntohs(iphdr->len),        iphdr->nexthdr,        iphdr->hoplim));  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",        ntohl(iphdr->src.addr[0]) >> 16 & 0xffff,        ntohl(iphdr->src.addr[0]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",        ntohl(iphdr->src.addr[1]) >> 16 & 0xffff,        ntohl(iphdr->src.addr[1]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",        ntohl(iphdr->src.addr[2]) >> 16 & 0xffff,        ntohl(iphdr->src.addr[2]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (src)\n",        ntohl(iphdr->src.addr[3]) >> 16 & 0xffff,        ntohl(iphdr->src.addr[3]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",        ntohl(iphdr->dest.addr[0]) >> 16 & 0xffff,        ntohl(iphdr->dest.addr[0]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",        ntohl(iphdr->dest.addr[1]) >> 16 & 0xffff,        ntohl(iphdr->dest.addr[1]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",        ntohl(iphdr->dest.addr[2]) >> 16 & 0xffff,        ntohl(iphdr->dest.addr[2]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("|       %4lx      |       %4lx     | (dest)\n",        ntohl(iphdr->dest.addr[3]) >> 16 & 0xffff,        ntohl(iphdr->dest.addr[3]) & 0xffff));  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));}#endif /* IP_DEBUG */