lwip_icmp6.c

00001 /**
00002  * @file
00003  *
00004  * IPv6 version of ICMP, as per RFC 4443.
00005  */
00006 
00007 /*
00008  * Copyright (c) 2010 Inico Technologies Ltd.
00009  * All rights reserved.
00010  *
00011  * Redistribution and use in source and binary forms, with or without modification,
00012  * are permitted provided that the following conditions are met:
00013  *
00014  * 1. Redistributions of source code must retain the above copyright notice,
00015  *    this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright notice,
00017  *    this list of conditions and the following disclaimer in the documentation
00018  *    and/or other materials provided with the distribution.
00019  * 3. The name of the author may not be used to endorse or promote products
00020  *    derived from this software without specific prior written permission.
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00023  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00024  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00025  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00026  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00027  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00030  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00031  * OF SUCH DAMAGE.
00032  *
00033  * This file is part of the lwIP TCP/IP stack.
00034  *
00035  * Author: Ivan Delamer <delamer@inicotech.com>
00036  *
00037  *
00038  * Please coordinate changes and requests with Ivan Delamer
00039  * <delamer@inicotech.com>
00040  */
00041 
00042 #include "lwip/opt.h"
00043 
00044 #if LWIP_ICMP6 && LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
00045 
00046 #include "lwip/icmp6.h"
00047 #include "lwip/ip6.h"
00048 #include "lwip/ip6_addr.h"
00049 #include "lwip/inet_chksum.h"
00050 #include "lwip/pbuf.h"
00051 #include "lwip/netif.h"
00052 #include "lwip/nd6.h"
00053 #include "lwip/mld6.h"
00054 #include "lwip/ip.h"
00055 #include "lwip/stats.h"
00056 
00057 #include <string.h>
00058 
00059 #ifndef LWIP_ICMP6_DATASIZE
00060 #define LWIP_ICMP6_DATASIZE   8
00061 #endif
00062 #if LWIP_ICMP6_DATASIZE == 0
00063 #define LWIP_ICMP6_DATASIZE   8
00064 #endif
00065 
00066 /* Forward declarations */
00067 static void icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type);
00068 
00069 
00070 /**
00071  * Process an input ICMPv6 message. Called by ip6_input.
00072  *
00073  * Will generate a reply for echo requests. Other messages are forwarded
00074  * to nd6_input, or mld6_input.
00075  *
00076  * @param p the mld packet, p->payload pointing to the icmpv6 header
00077  * @param inp the netif on which this packet was received
00078  */
00079 void
00080 icmp6_input(struct pbuf *p, struct netif *inp)
00081 {
00082   struct icmp6_hdr *icmp6hdr;
00083   struct pbuf * r;
00084   const ip6_addr_t * reply_src;
00085 
00086   ICMP6_STATS_INC(icmp6.recv);
00087 
00088   /* Check that ICMPv6 header fits in payload */
00089   if (p->len < sizeof(struct icmp6_hdr)) {
00090     /* drop short packets */
00091     pbuf_free(p);
00092     ICMP6_STATS_INC(icmp6.lenerr);
00093     ICMP6_STATS_INC(icmp6.drop);
00094     return;
00095   }
00096 
00097   icmp6hdr = (struct icmp6_hdr *)p->payload;
00098 
00099 #if CHECKSUM_CHECK_ICMP6
00100   IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP6) {
00101     if (ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->tot_len, ip6_current_src_addr(),
00102                           ip6_current_dest_addr()) != 0) {
00103       /* Checksum failed */
00104       pbuf_free(p);
00105       ICMP6_STATS_INC(icmp6.chkerr);
00106       ICMP6_STATS_INC(icmp6.drop);
00107       return;
00108     }
00109   }
00110 #endif /* CHECKSUM_CHECK_ICMP6 */
00111 
00112   switch (icmp6hdr->type) {
00113   case ICMP6_TYPE_NA: /* Neighbor advertisement */
00114   case ICMP6_TYPE_NS: /* Neighbor solicitation */
00115   case ICMP6_TYPE_RA: /* Router advertisement */
00116   case ICMP6_TYPE_RD: /* Redirect */
00117   case ICMP6_TYPE_PTB: /* Packet too big */
00118     nd6_input(p, inp);
00119     return;
00120     break;
00121   case ICMP6_TYPE_RS:
00122 #if LWIP_IPV6_FORWARD
00123     /* @todo implement router functionality */
00124 #endif
00125     break;
00126 #if LWIP_IPV6_MLD
00127   case ICMP6_TYPE_MLQ:
00128   case ICMP6_TYPE_MLR:
00129   case ICMP6_TYPE_MLD:
00130     mld6_input(p, inp);
00131     return;
00132     break;
00133 #endif
00134   case ICMP6_TYPE_EREQ:
00135 #if !LWIP_MULTICAST_PING
00136     /* multicast destination address? */
00137     if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
00138       /* drop */
00139       pbuf_free(p);
00140       ICMP6_STATS_INC(icmp6.drop);
00141       return;
00142     }
00143 #endif /* LWIP_MULTICAST_PING */
00144 
00145     /* Allocate reply. */
00146     r = pbuf_alloc(PBUF_IP, p->tot_len, PBUF_RAM);
00147     if (r == NULL) {
00148       /* drop */
00149       pbuf_free(p);
00150       ICMP6_STATS_INC(icmp6.memerr);
00151       return;
00152     }
00153 
00154     /* Copy echo request. */
00155     if (pbuf_copy(r, p) != ERR_OK) {
00156       /* drop */
00157       pbuf_free(p);
00158       pbuf_free(r);
00159       ICMP6_STATS_INC(icmp6.err);
00160       return;
00161     }
00162 
00163     /* Determine reply source IPv6 address. */
00164 #if LWIP_MULTICAST_PING
00165     if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
00166       reply_src = ip_2_ip6(ip6_select_source_address(inp, ip6_current_src_addr()));
00167       if (reply_src == NULL) {
00168         /* drop */
00169         pbuf_free(p);
00170         pbuf_free(r);
00171         ICMP6_STATS_INC(icmp6.rterr);
00172         return;
00173       }
00174     }
00175     else
00176 #endif /* LWIP_MULTICAST_PING */
00177     {
00178       reply_src = ip6_current_dest_addr();
00179     }
00180 
00181     /* Set fields in reply. */
00182     ((struct icmp6_echo_hdr *)(r->payload))->type = ICMP6_TYPE_EREP;
00183     ((struct icmp6_echo_hdr *)(r->payload))->chksum = 0;
00184 #if CHECKSUM_GEN_ICMP6
00185     IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP6) {
00186       ((struct icmp6_echo_hdr *)(r->payload))->chksum = ip6_chksum_pseudo(r,
00187           IP6_NEXTH_ICMP6, r->tot_len, reply_src, ip6_current_src_addr());
00188     }
00189 #endif /* CHECKSUM_GEN_ICMP6 */
00190 
00191     /* Send reply. */
00192     ICMP6_STATS_INC(icmp6.xmit);
00193     ip6_output_if(r, reply_src, ip6_current_src_addr(),
00194         LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, inp);
00195     pbuf_free(r);
00196 
00197     break;
00198   default:
00199     ICMP6_STATS_INC(icmp6.proterr);
00200     ICMP6_STATS_INC(icmp6.drop);
00201     break;
00202   }
00203 
00204   pbuf_free(p);
00205 }
00206 
00207 
00208 /**
00209  * Send an icmpv6 'destination unreachable' packet.
00210  *
00211  * @param p the input packet for which the 'unreachable' should be sent,
00212  *          p->payload pointing to the IPv6 header
00213  * @param c ICMPv6 code for the unreachable type
00214  */
00215 void
00216 icmp6_dest_unreach(struct pbuf *p, enum icmp6_dur_code c)
00217 {
00218   icmp6_send_response(p, c, 0, ICMP6_TYPE_DUR);
00219 }
00220 
00221 /**
00222  * Send an icmpv6 'packet too big' packet.
00223  *
00224  * @param p the input packet for which the 'packet too big' should be sent,
00225  *          p->payload pointing to the IPv6 header
00226  * @param mtu the maximum mtu that we can accept
00227  */
00228 void
00229 icmp6_packet_too_big(struct pbuf *p, u32_t mtu)
00230 {
00231   icmp6_send_response(p, 0, mtu, ICMP6_TYPE_PTB);
00232 }
00233 
00234 /**
00235  * Send an icmpv6 'time exceeded' packet.
00236  *
00237  * @param p the input packet for which the 'unreachable' should be sent,
00238  *          p->payload pointing to the IPv6 header
00239  * @param c ICMPv6 code for the time exceeded type
00240  */
00241 void
00242 icmp6_time_exceeded(struct pbuf *p, enum icmp6_te_code c)
00243 {
00244   icmp6_send_response(p, c, 0, ICMP6_TYPE_TE);
00245 }
00246 
00247 /**
00248  * Send an icmpv6 'parameter problem' packet.
00249  *
00250  * @param p the input packet for which the 'param problem' should be sent,
00251  *          p->payload pointing to the IP header
00252  * @param c ICMPv6 code for the param problem type
00253  * @param pointer the pointer to the byte where the parameter is found
00254  */
00255 void
00256 icmp6_param_problem(struct pbuf *p, enum icmp6_pp_code c, u32_t pointer)
00257 {
00258   icmp6_send_response(p, c, pointer, ICMP6_TYPE_PP);
00259 }
00260 
00261 /**
00262  * Send an ICMPv6 packet in response to an incoming packet.
00263  *
00264  * @param p the input packet for which the response should be sent,
00265  *          p->payload pointing to the IPv6 header
00266  * @param code Code of the ICMPv6 header
00267  * @param data Additional 32-bit parameter in the ICMPv6 header
00268  * @param type Type of the ICMPv6 header
00269  */
00270 static void
00271 icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type)
00272 {
00273   struct pbuf *q;
00274   struct icmp6_hdr *icmp6hdr;
00275   const ip6_addr_t *reply_src;
00276   ip6_addr_t *reply_dest;
00277   ip6_addr_t reply_src_local, reply_dest_local;
00278   struct ip6_hdr *ip6hdr;
00279   struct netif *netif;
00280 
00281   /* ICMPv6 header + IPv6 header + data */
00282   q = pbuf_alloc(PBUF_IP, sizeof(struct icmp6_hdr) + IP6_HLEN + LWIP_ICMP6_DATASIZE,
00283                  PBUF_RAM);
00284   if (q == NULL) {
00285     LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMPv6 packet.\n"));
00286     ICMP6_STATS_INC(icmp6.memerr);
00287     return;
00288   }
00289   LWIP_ASSERT("check that first pbuf can hold icmp 6message",
00290              (q->len >= (sizeof(struct icmp6_hdr) + IP6_HLEN + LWIP_ICMP6_DATASIZE)));
00291 
00292   icmp6hdr = (struct icmp6_hdr *)q->payload;
00293   icmp6hdr->type = type;
00294   icmp6hdr->code = code;
00295   icmp6hdr->data = data;
00296 
00297   /* copy fields from original packet */
00298   SMEMCPY((u8_t *)q->payload + sizeof(struct icmp6_hdr), (u8_t *)p->payload,
00299           IP6_HLEN + LWIP_ICMP6_DATASIZE);
00300 
00301   /* Get the destination address and netif for this ICMP message. */
00302   if ((ip_current_netif() == NULL) ||
00303       ((code == ICMP6_TE_FRAG) && (type == ICMP6_TYPE_TE))) {
00304     /* Special case, as ip6_current_xxx is either NULL, or points
00305      * to a different packet than the one that expired.
00306      * We must use the addresses that are stored in the expired packet. */
00307     ip6hdr = (struct ip6_hdr *)p->payload;
00308     /* copy from packed address to aligned address */
00309     ip6_addr_copy(reply_dest_local, ip6hdr->src);
00310     ip6_addr_copy(reply_src_local, ip6hdr->dest);
00311     reply_dest = &reply_dest_local;
00312     reply_src = &reply_src_local;
00313     netif = ip6_route(reply_src, reply_dest);
00314     if (netif == NULL) {
00315       /* drop */
00316       pbuf_free(q);
00317       ICMP6_STATS_INC(icmp6.rterr);
00318       return;
00319     }
00320   }
00321   else {
00322     netif = ip_current_netif();
00323     reply_dest = ip6_current_src_addr();
00324 
00325     /* Select an address to use as source. */
00326     reply_src = ip_2_ip6(ip6_select_source_address(netif, reply_dest));
00327     if (reply_src == NULL) {
00328       /* drop */
00329       pbuf_free(q);
00330       ICMP6_STATS_INC(icmp6.rterr);
00331       return;
00332     }
00333   }
00334 
00335   /* calculate checksum */
00336   icmp6hdr->chksum = 0;
00337 #if CHECKSUM_GEN_ICMP6
00338   IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
00339     icmp6hdr->chksum = ip6_chksum_pseudo(q, IP6_NEXTH_ICMP6, q->tot_len,
00340       reply_src, reply_dest);
00341   }
00342 #endif /* CHECKSUM_GEN_ICMP6 */
00343 
00344   ICMP6_STATS_INC(icmp6.xmit);
00345   ip6_output_if(q, reply_src, reply_dest, LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif);
00346   pbuf_free(q);
00347 }
00348 
00349 #endif /* LWIP_ICMP6 && LWIP_IPV6 */