sys/netinet6/route6.c

   1 /*      $FreeBSD: src/sys/netinet6/route6.c,v 1.1.2.5 2003/01/23 21:06:47 sam Exp $     */
   2 /*      $DragonFly: src/sys/netinet6/route6.c,v 1.5 2004/09/14 21:00:01 joerg Exp $     */
   3 /*      $KAME: route6.c,v 1.24 2001/03/14 03:07:05 itojun Exp $ */
   4
   5 /*
   6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the project nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "opt_inet.h"
  35 #include "opt_inet6.h"
  36
  37 #include <sys/param.h>
  38 #include <sys/mbuf.h>
  39 #include <sys/socket.h>
  40 #include <sys/systm.h>
  41 #include <sys/queue.h>
  42
  43 #include <net/if.h>
  44
  45 #include <netinet/in.h>
  46 #include <netinet6/in6_var.h>
  47 #include <netinet/ip6.h>
  48 #include <netinet6/ip6_var.h>
  49
  50 #include <netinet/icmp6.h>
  51
  52 static int ip6_rthdr0 (struct mbuf *, struct ip6_hdr *,
  53     struct ip6_rthdr0 *);
  54
  55 int
  56 route6_input(struct mbuf **mp, int *offp, int proto) /* proto is unused */
  57 {
  58         struct ip6_hdr *ip6;
  59         struct mbuf *m = *mp;
  60         struct ip6_rthdr *rh;
  61         int off = *offp, rhlen;
  62
  63 #ifndef PULLDOWN_TEST
  64         IP6_EXTHDR_CHECK(m, off, sizeof(*rh), IPPROTO_DONE);
  65         ip6 = mtod(m, struct ip6_hdr *);
  66         rh = (struct ip6_rthdr *)((caddr_t)ip6 + off);
  67 #else
  68         ip6 = mtod(m, struct ip6_hdr *);
  69         IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, sizeof(*rh));
  70         if (rh == NULL) {
  71                 ip6stat.ip6s_tooshort++;
  72                 return IPPROTO_DONE;
  73         }
  74 #endif
  75
  76         switch (rh->ip6r_type) {
  77         case IPV6_RTHDR_TYPE_0:
  78                 rhlen = (rh->ip6r_len + 1) << 3;
  79 #ifndef PULLDOWN_TEST
  80                 /*
  81                  * note on option length:
  82                  * due to IP6_EXTHDR_CHECK assumption, we cannot handle
  83                  * very big routing header (max rhlen == 2048).
  84                  */
  85                 IP6_EXTHDR_CHECK(m, off, rhlen, IPPROTO_DONE);
  86 #else
  87                 /*
  88                  * note on option length:
  89                  * maximum rhlen: 2048
  90                  * max mbuf m_pulldown can handle: MCLBYTES == usually 2048
  91                  * so, here we are assuming that m_pulldown can handle
  92                  * rhlen == 2048 case.  this may not be a good thing to
  93                  * assume - we may want to avoid pulling it up altogether.
  94                  */
  95                 IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, rhlen);
  96                 if (rh == NULL) {
  97                         ip6stat.ip6s_tooshort++;
  98                         return IPPROTO_DONE;
  99                 }
 100 #endif
 101                 if (ip6_rthdr0(m, ip6, (struct ip6_rthdr0 *)rh))
 102                         return(IPPROTO_DONE);
 103                 break;
 104         default:
 105                 /* unknown routing type */
 106                 if (rh->ip6r_segleft == 0) {
 107                         rhlen = (rh->ip6r_len + 1) << 3;
 108                         break;  /* Final dst. Just ignore the header. */
 109                 }
 110                 ip6stat.ip6s_badoptions++;
 111                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 112                             (caddr_t)&rh->ip6r_type - (caddr_t)ip6);
 113                 return(IPPROTO_DONE);
 114         }
 115
 116         *offp += rhlen;
 117         return(rh->ip6r_nxt);
 118 }
 119
 120 /*
 121  * Type0 routing header processing
 122  *
 123  * RFC2292 backward compatibility warning: no support for strict/loose bitmap,
 124  * as it was dropped between RFC1883 and RFC2460.
 125  */
 126 static int
 127 ip6_rthdr0(struct mbuf *m, struct ip6_hdr *ip6, struct ip6_rthdr0 *rh0)
 128 {
 129         int addrs, index;
 130         struct in6_addr *nextaddr, tmpaddr;
 131
 132         if (rh0->ip6r0_segleft == 0)
 133                 return(0);
 134
 135         if (rh0->ip6r0_len % 2
 136 #ifdef COMPAT_RFC1883
 137             || rh0->ip6r0_len > 46
 138 #endif
 139                 ) {
 140                 /*
 141                  * Type 0 routing header can't contain more than 23 addresses.
 142                  * RFC 2462: this limitation was removed since strict/loose
 143                  * bitmap field was deleted.
 144                  */
 145                 ip6stat.ip6s_badoptions++;
 146                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 147                             (caddr_t)&rh0->ip6r0_len - (caddr_t)ip6);
 148                 return(-1);
 149         }
 150
 151         if ((addrs = rh0->ip6r0_len / 2) < rh0->ip6r0_segleft) {
 152                 ip6stat.ip6s_badoptions++;
 153                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 154                             (caddr_t)&rh0->ip6r0_segleft - (caddr_t)ip6);
 155                 return(-1);
 156         }
 157
 158         index = addrs - rh0->ip6r0_segleft;
 159         rh0->ip6r0_segleft--;
 160         /* note that ip6r0_addr does not exist in RFC2292bis */
 161         nextaddr = rh0->ip6r0_addr + index;
 162
 163         /*
 164          * reject invalid addresses.  be proactive about malicious use of
 165          * IPv4 mapped/compat address.
 166          * XXX need more checks?
 167          */
 168         if (IN6_IS_ADDR_MULTICAST(nextaddr) ||
 169             IN6_IS_ADDR_UNSPECIFIED(nextaddr) ||
 170             IN6_IS_ADDR_V4MAPPED(nextaddr) ||
 171             IN6_IS_ADDR_V4COMPAT(nextaddr)) {
 172                 ip6stat.ip6s_badoptions++;
 173                 m_freem(m);
 174                 return(-1);
 175         }
 176         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 177             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst) ||
 178             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst) ||
 179             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
 180                 ip6stat.ip6s_badoptions++;
 181                 m_freem(m);
 182                 return(-1);
 183         }
 184
 185         /*
 186          * Swap the IPv6 destination address and nextaddr. Forward the packet.
 187          */
 188         tmpaddr = *nextaddr;
 189         *nextaddr = ip6->ip6_dst;
 190         if (IN6_IS_ADDR_LINKLOCAL(nextaddr))
 191                 nextaddr->s6_addr16[1] = 0;
 192         ip6->ip6_dst = tmpaddr;
 193         if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
 194                 ip6->ip6_dst.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
 195
 196 #ifdef COMPAT_RFC1883
 197         if (rh0->ip6r0_slmap[index / 8] & (1 << (7 - (index % 8))))
 198                 ip6_forward(m, IPV6_SRCRT_NEIGHBOR);
 199         else
 200                 ip6_forward(m, IPV6_SRCRT_NOTNEIGHBOR);
 201 #else
 202         ip6_forward(m, 1);
 203 #endif
 204
 205         return(-1);                     /* m would be freed in ip6_forward() */
 206 }