ip6.c

00001 /*
00002  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without modification,
00006  * are permitted provided that the following conditions are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright notice,
00009  *    this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright notice,
00011  *    this list of conditions and the following disclaimer in the documentation
00012  *    and/or other materials provided with the distribution.
00013  * 3. The name of the author may not be used to endorse or promote products
00014  *    derived from this software without specific prior written permission.
00015  *
00016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00025  * OF SUCH DAMAGE.
00026  *
00027  * This file is part of the lwIP TCP/IP stack.
00028  *
00029  * Author: Adam Dunkels <adam@sics.se>
00030  *
00031  */
00032 
00033 
00034 
00035 /* ip.c
00036  *
00037  * This is the code for the IP layer for IPv6.
00038  *
00039  */
00040 
00041 
00042 #include "lwip/opt.h"
00043 
00044 #if IPv6
00045 
00046 #include "lwip/def.h"
00047 #include "lwip/mem.h"
00048 #include "ipv6/lwip/ip.h"
00049 #include "ipv6/lwip/inet.h"
00050 #include "lwip/netif.h"
00051 #include "ipv6/lwip/icmp.h"
00052 #include "lwip/udp.h"
00053 #include "lwip/tcp.h"
00054 
00055 #include "lwip/stats.h"
00056 
00057 #include "arch/perf.h"
00058 
00059 /* ip_init:
00060  *
00061  * Initializes the IP layer.
00062  */
00063 
00064 void
00065 ip_init(void)
00066 {
00067 }
00068 
00069 /* ip_route:
00070  *
00071  * Finds the appropriate network interface for a given IP address. It searches the
00072  * list of network interfaces linearly. A match is found if the masked IP address of
00073  * the network interface equals the masked IP address given to the function.
00074  */
00075 
00076 struct netif *
00077 ip_route(struct ip_addr *dest)
00078 {
00079   struct netif *netif;
00080 
00081   for(netif = netif_list; netif != NULL; netif = netif->next) {
00082     if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
00083       return netif;
00084     }
00085   }
00086 
00087   return netif_default;
00088 }
00089 
00090 /* ip_forward:
00091  *
00092  * Forwards an IP packet. It finds an appropriate route for the packet, decrements
00093  * the TTL value of the packet, adjusts the checksum and outputs the packet on the
00094  * appropriate interface.
00095  */
00096 
00097 static void
00098 ip_forward(struct pbuf *p, struct ip_hdr *iphdr)
00099 {
00100   struct netif *netif;
00101 
00102   PERF_START;
00103 
00104   if ((netif = ip_route((struct ip_addr *)&(iphdr->dest))) == NULL) {
00105 
00106     LWIP_DEBUGF(IP_DEBUG, ("ip_input: no forwarding route found for "));
00107 #if IP_DEBUG
00108     ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
00109 #endif /* IP_DEBUG */
00110     LWIP_DEBUGF(IP_DEBUG, ("\n"));
00111     pbuf_free(p);
00112     return;
00113   }
00114   /* Decrement TTL and send ICMP if ttl == 0. */
00115   if (--iphdr->hoplim == 0) {
00116 #if LWIP_ICMP
00117     /* Don't send ICMP messages in response to ICMP messages */
00118     if (iphdr->nexthdr != IP_PROTO_ICMP) {
00119       icmp_time_exceeded(p, ICMP_TE_TTL);
00120     }
00121 #endif /* LWIP_ICMP */
00122     pbuf_free(p);
00123     return;
00124   }
00125 
00126   /* Incremental update of the IP checksum. */
00127   /*  if (iphdr->chksum >= htons(0xffff - 0x100)) {
00128     iphdr->chksum += htons(0x100) + 1;
00129   } else {
00130     iphdr->chksum += htons(0x100);
00131     }*/
00132 
00133 
00134   LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to "));
00135 #if IP_DEBUG
00136   ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
00137 #endif /* IP_DEBUG */
00138   LWIP_DEBUGF(IP_DEBUG, ("\n"));
00139 
00140   IP_STATS_INC(ip.fw);
00141   IP_STATS_INC(ip.xmit);
00142 
00143   PERF_STOP("ip_forward");
00144 
00145   netif->output(netif, p, (struct ip_addr *)&(iphdr->dest));
00146 }
00147 
00148 /* ip_input:
00149  *
00150  * This function is called by the network interface device driver when an IP packet is
00151  * received. The function does the basic checks of the IP header such as packet size
00152  * being at least larger than the header size etc. If the packet was not destined for
00153  * us, the packet is forwarded (using ip_forward). The IP checksum is always checked.
00154  *
00155  * Finally, the packet is sent to the upper layer protocol input function.
00156  */
00157 
00158 void
00159 ip_input(struct pbuf *p, struct netif *inp) {
00160   struct ip_hdr *iphdr;
00161   struct netif *netif;
00162 
00163 
00164   PERF_START;
00165 
00166 #if IP_DEBUG
00167   ip_debug_print(p);
00168 #endif /* IP_DEBUG */
00169 
00170 
00171   IP_STATS_INC(ip.recv);
00172 
00173   /* identify the IP header */
00174   iphdr = static_cast<struct ip_hdr *>(p->payload);
00175 
00176 
00177   if (iphdr->v != 6) {
00178     LWIP_DEBUGF(IP_DEBUG, ("IP packet dropped due to bad version number\n"));
00179 #if IP_DEBUG
00180     ip_debug_print(p);
00181 #endif /* IP_DEBUG */
00182     pbuf_free(p);
00183     IP_STATS_INC(ip.err);
00184     IP_STATS_INC(ip.drop);
00185     return;
00186   }
00187 
00188   /* is this packet for us? */
00189   for(netif = netif_list; netif != NULL; netif = netif->next) {
00190 #if IP_DEBUG
00191     LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest "));
00192     ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
00193     LWIP_DEBUGF(IP_DEBUG, ("netif->ip_addr "));
00194     ip_addr_debug_print(IP_DEBUG, ((struct ip_addr *)&(iphdr->dest)));
00195     LWIP_DEBUGF(IP_DEBUG, ("\n"));
00196 #endif /* IP_DEBUG */
00197     if (ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr))) {
00198       break;
00199     }
00200   }
00201 
00202 
00203   if (netif == NULL) {
00204     /* packet not for us, route or discard */
00205 #if IP_FORWARD
00206     ip_forward(p, iphdr);
00207 #endif
00208     pbuf_free(p);
00209     return;
00210   }
00211 
00212   pbuf_realloc(p, IP_HLEN + ntohs(iphdr->len));
00213 
00214   /* send to upper layers */
00215 #if IP_DEBUG
00216   /*  LWIP_DEBUGF("ip_input: \n");
00217   ip_debug_print(p);
00218   LWIP_DEBUGF("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len);*/
00219 #endif /* IP_DEBUG */
00220 
00221   if(pbuf_header(p, -IP_HLEN)) {
00222     LWIP_ASSERT("Can't move over header in packet", 0);
00223     return;
00224   }
00225 
00226   switch (iphdr->nexthdr) {
00227   case IP_PROTO_UDP:
00228     udp_input(p, inp);
00229     break;
00230   case IP_PROTO_TCP:
00231     tcp_input(p, inp);
00232     break;
00233 #if LWIP_ICMP
00234   case IP_PROTO_ICMP:
00235     icmp_input(p, inp);
00236     break;
00237 #endif /* LWIP_ICMP */
00238   default:
00239 #if LWIP_ICMP
00240     /* send ICMP destination protocol unreachable */
00241     icmp_dest_unreach(p, ICMP_DUR_PROTO);
00242 #endif /* LWIP_ICMP */
00243     pbuf_free(p);
00244     LWIP_DEBUGF(IP_DEBUG, ("Unsupported transport protocol %"U16_F"\n",
00245           iphdr->nexthdr));
00246 
00247     IP_STATS_INC(ip.proterr);
00248     IP_STATS_INC(ip.drop);
00249   }
00250   PERF_STOP("ip_input");
00251 }
00252 
00253 
00254 /* ip_output_if:
00255  *
00256  * Sends an IP packet on a network interface. This function constructs the IP header
00257  * and calculates the IP header checksum. If the source IP address is NULL,
00258  * the IP address of the outgoing network interface is filled in as source address.
00259  */
00260 
00261 err_t
00262 ip_output_if (struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
00263        u8_t ttl,
00264        u8_t proto, struct netif *netif)
00265 {
00266   struct ip_hdr *iphdr;
00267 
00268   PERF_START;
00269 
00270   LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));
00271   if (pbuf_header(p, IP_HLEN)) {
00272     LWIP_DEBUGF(IP_DEBUG, ("ip_output: not enough room for IP header in pbuf\n"));
00273     IP_STATS_INC(ip.err);
00274 
00275     return ERR_BUF;
00276   }
00277   LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));
00278 
00279   iphdr = static_cast<struct ip_hdr *>(p->payload);
00280 
00281 
00282   if (dest != IP_HDRINCL) {
00283     LWIP_DEBUGF(IP_DEBUG, ("!IP_HDRLINCL\n"));
00284     iphdr->hoplim = ttl;
00285     iphdr->nexthdr = proto;
00286     iphdr->len = htons(p->tot_len - IP_HLEN);
00287     ip_addr_set(&(iphdr->dest), dest);
00288 
00289     iphdr->v = 6;
00290 
00291     if (ip_addr_isany(src)) {
00292       ip_addr_set(&(iphdr->src), &(netif->ip_addr));
00293     } else {
00294       ip_addr_set(&(iphdr->src), src);
00295     }
00296 
00297   } else {
00298     dest = &(iphdr->dest);
00299   }
00300 
00301   IP_STATS_INC(ip.xmit);
00302 
00303   LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c (len %"U16_F")\n", netif->name[0], netif->name[1], p->tot_len));
00304 #if IP_DEBUG
00305   ip_debug_print(p);
00306 #endif /* IP_DEBUG */
00307 
00308   PERF_STOP("ip_output_if");
00309   return netif->output(netif, p, dest);
00310 }
00311 
00312 /* ip_output:
00313  *
00314  * Simple interface to ip_output_if. It finds the outgoing network interface and
00315  * calls upon ip_output_if to do the actual work.
00316  */
00317 
00318 err_t
00319 ip_output(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
00320     u8_t ttl, u8_t proto)
00321 {
00322   struct netif *netif;
00323   if ((netif = ip_route(dest)) == NULL) {
00324     LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));
00325     IP_STATS_INC(ip.rterr);
00326     return ERR_RTE;
00327   }
00328 
00329   return ip_output_if (p, src, dest, ttl, proto, netif);
00330 }
00331 
00332 #if IP_DEBUG
00333 void
00334 ip_debug_print(struct pbuf *p)
00335 {
00336   struct ip_hdr *iphdr = p->payload;
00337 
00338   LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
00339   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
00340   LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |  %"X16_F"%"X16_F"  |      %"X16_F"%"X16_F"           | (v, traffic class, flow label)\n",
00341         iphdr->v,
00342         iphdr->tclass1, iphdr->tclass2,
00343         iphdr->flow1, iphdr->flow2));
00344   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
00345   LWIP_DEBUGF(IP_DEBUG, ("|    %5"U16_F"      | %2"U16_F"  |  %2"U16_F"   | (len, nexthdr, hoplim)\n",
00346         ntohs(iphdr->len),
00347         iphdr->nexthdr,
00348         iphdr->hoplim));
00349   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
00350   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
00351         (ntohl(iphdr->src.addr[0]) >> 16) & 0xffff,
00352         ntohl(iphdr->src.addr[0]) & 0xffff));
00353   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
00354         (ntohl(iphdr->src.addr[1]) >> 16) & 0xffff,
00355         ntohl(iphdr->src.addr[1]) & 0xffff));
00356   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
00357         (ntohl(iphdr->src.addr[2]) >> 16) & 0xffff,
00358         ntohl(iphdr->src.addr[2]) & 0xffff));
00359   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
00360         (ntohl(iphdr->src.addr[3]) >> 16) & 0xffff,
00361         ntohl(iphdr->src.addr[3]) & 0xffff));
00362   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
00363   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
00364         (ntohl(iphdr->dest.addr[0]) >> 16) & 0xffff,
00365         ntohl(iphdr->dest.addr[0]) & 0xffff));
00366   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
00367         (ntohl(iphdr->dest.addr[1]) >> 16) & 0xffff,
00368         ntohl(iphdr->dest.addr[1]) & 0xffff));
00369   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
00370         (ntohl(iphdr->dest.addr[2]) >> 16) & 0xffff,
00371         ntohl(iphdr->dest.addr[2]) & 0xffff));
00372   LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
00373         (ntohl(iphdr->dest.addr[3]) >> 16) & 0xffff,
00374         ntohl(iphdr->dest.addr[3]) & 0xffff));
00375   LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
00376 }
00377 #endif /* IP_DEBUG */
00378 
00379 #endif /* IPv6 */