bsd/netinet6/route6.c

   1 /*      $FreeBSD: src/sys/netinet6/route6.c,v 1.1.2.3 2001/07/03 11:01:55 ume Exp $     */
   2 /*      $KAME: route6.c,v 1.24 2001/03/14 03:07:05 itojun Exp $ */
   3
   4 /*
   5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/mbuf.h>
  35 #include <sys/socket.h>
  36 #include <sys/queue.h>
  37 #include <string.h>
  38
  39 #include <net/if.h>
  40 #include <net/route.h>
  41
  42 #include <netinet/in.h>
  43 #include <netinet6/in6_var.h>
  44 #include <netinet/ip6.h>
  45 #include <netinet6/ip6_var.h>
  46
  47 #include <netinet/icmp6.h>
  48
  49 #if IP6_RTHDR0_ALLOWED
  50 static int ip6_rthdr0(struct mbuf *, struct ip6_hdr *,
  51     struct ip6_rthdr0 *);
  52 #endif /* IP6_RTHDR0_ALLOWED */
  53
  54 int
  55 route6_input(struct mbuf **mp, int *offp)
  56 {
  57         struct ip6_hdr *ip6;
  58         struct mbuf *m = *mp;
  59         struct ip6_rthdr *rh;
  60         int off = *offp, rhlen;
  61         struct ip6aux *ip6a;
  62
  63         ip6a = ip6_findaux(m);
  64         if (ip6a) {
  65                 /* XXX reject home-address option before rthdr */
  66                 if (ip6a->ip6a_flags & IP6A_SWAP) {
  67                         ip6stat.ip6s_badoptions++;
  68                         m_freem(m);
  69                         return IPPROTO_DONE;
  70                 }
  71         }
  72
  73 #ifndef PULLDOWN_TEST
  74         IP6_EXTHDR_CHECK(m, off, sizeof(*rh), return IPPROTO_DONE);
  75         ip6 = mtod(m, struct ip6_hdr *);
  76         rh = (struct ip6_rthdr *)((caddr_t)ip6 + off);
  77 #else
  78         ip6 = mtod(m, struct ip6_hdr *);
  79         IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, sizeof(*rh));
  80         if (rh == NULL) {
  81                 ip6stat.ip6s_tooshort++;
  82                 return IPPROTO_DONE;
  83         }
  84 #endif
  85
  86         switch (rh->ip6r_type) {
  87 #if IP6_RTHDR0_ALLOWED
  88         case IPV6_RTHDR_TYPE_0:
  89                 rhlen = (rh->ip6r_len + 1) << 3;
  90 #ifndef PULLDOWN_TEST
  91                 /*
  92                  * note on option length:
  93                  * due to IP6_EXTHDR_CHECK assumption, we cannot handle
  94                  * very big routing header (max rhlen == 2048).
  95                  */
  96                 IP6_EXTHDR_CHECK(m, off, rhlen, return IPPROTO_DONE);
  97 #else
  98                 /*
  99                  * note on option length:
 100                  * maximum rhlen: 2048
 101                  * max mbuf m_pulldown can handle: MCLBYTES == usually 2048
 102                  * so, here we are assuming that m_pulldown can handle
 103                  * rhlen == 2048 case.  this may not be a good thing to
 104                  * assume - we may want to avoid pulling it up altogether.
 105                  */
 106                 IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, rhlen);
 107                 if (rh == NULL) {
 108                         ip6stat.ip6s_tooshort++;
 109                         return IPPROTO_DONE;
 110                 }
 111 #endif
 112                 if (ip6_rthdr0(m, ip6, (struct ip6_rthdr0 *)rh))
 113                         return(IPPROTO_DONE);
 114                 break;
 115 #endif /* IP6_RTHDR0_ALLOWED */
 116         default:
 117                 /* unknown routing type */
 118                 if (rh->ip6r_segleft == 0) {
 119                         rhlen = (rh->ip6r_len + 1) << 3;
 120                         break;  /* Final dst. Just ignore the header. */
 121                 }
 122                 ip6stat.ip6s_badoptions++;
 123                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 124                             (caddr_t)&rh->ip6r_type - (caddr_t)ip6);
 125                 return(IPPROTO_DONE);
 126         }
 127
 128         *offp += rhlen;
 129         return(rh->ip6r_nxt);
 130 }
 131
 132 #if IP6_RTHDR0_ALLOWED
 133 /*
 134  * Type0 routing header processing
 135  *
 136  * RFC2292 backward compatibility warning: no support for strict/loose bitmap,
 137  * as it was dropped between RFC1883 and RFC2460.
 138  */
 139 static int
 140 ip6_rthdr0(m, ip6, rh0)
 141         struct mbuf *m;
 142         struct ip6_hdr *ip6;
 143         struct ip6_rthdr0 *rh0;
 144 {
 145         int addrs, index;
 146         struct in6_addr *nextaddr, tmpaddr;
 147         struct route_in6 ip6forward_rt;
 148
 149         if (rh0->ip6r0_segleft == 0)
 150                 return(0);
 151
 152         if (rh0->ip6r0_len % 2
 153 #if COMPAT_RFC1883
 154             || rh0->ip6r0_len > 46
 155 #endif
 156                 ) {
 157                 /*
 158                  * Type 0 routing header can't contain more than 23 addresses.
 159                  * RFC 2462: this limitation was removed since stict/loose
 160                  * bitmap field was deleted.
 161                  */
 162                 ip6stat.ip6s_badoptions++;
 163                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 164                             (caddr_t)&rh0->ip6r0_len - (caddr_t)ip6);
 165                 return(-1);
 166         }
 167
 168         if ((addrs = rh0->ip6r0_len / 2) < rh0->ip6r0_segleft) {
 169                 ip6stat.ip6s_badoptions++;
 170                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 171                             (caddr_t)&rh0->ip6r0_segleft - (caddr_t)ip6);
 172                 return(-1);
 173         }
 174
 175         index = addrs - rh0->ip6r0_segleft;
 176         rh0->ip6r0_segleft--;
 177         /* note that ip6r0_addr does not exist in RFC2292bis */
 178         nextaddr = rh0->ip6r0_addr + index;
 179
 180         /*
 181          * reject invalid addresses.  be proactive about malicious use of
 182          * IPv4 mapped/compat address.
 183          * XXX need more checks?
 184          */
 185         if (IN6_IS_ADDR_MULTICAST(nextaddr) ||
 186             IN6_IS_ADDR_UNSPECIFIED(nextaddr) ||
 187             IN6_IS_ADDR_V4MAPPED(nextaddr) ||
 188             IN6_IS_ADDR_V4COMPAT(nextaddr)) {
 189                 ip6stat.ip6s_badoptions++;
 190                 m_freem(m);
 191                 return(-1);
 192         }
 193         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 194             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst) ||
 195             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst) ||
 196             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
 197                 ip6stat.ip6s_badoptions++;
 198                 m_freem(m);
 199                 return(-1);
 200         }
 201
 202         /*
 203          * Swap the IPv6 destination address and nextaddr. Forward the packet.
 204          */
 205         tmpaddr = *nextaddr;
 206         *nextaddr = ip6->ip6_dst;
 207         if (IN6_IS_ADDR_LINKLOCAL(nextaddr))
 208                 nextaddr->s6_addr16[1] = 0;
 209         ip6->ip6_dst = tmpaddr;
 210         if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
 211                 ip6->ip6_dst.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
 212
 213         /*
 214          * Don't use the globally cached route to forward packet having
 215          * Type 0 routing header(s); instead, do an explicit lookup using
 216          * a local route entry variable, in case the next address in the
 217          * packet is bogus (which would otherwise unnecessarily invalidate
 218          * the globally cached route).
 219          */
 220         bzero(&ip6forward_rt, sizeof (ip6forward_rt));
 221
 222 #if COMPAT_RFC1883
 223         if (rh0->ip6r0_slmap[index / 8] & (1 << (7 - (index % 8))))
 224                 ip6_forward(m, &ip6forward_rt, IPV6_SRCRT_NEIGHBOR, 0);
 225         else
 226                 ip6_forward(m, &ip6forward_rt, IPV6_SRCRT_NOTNEIGHBOR, 0);
 227 #else
 228         ip6_forward(m, &ip6forward_rt, 1, 0);
 229 #endif
 230
 231         /* Release reference to the looked up route */
 232         if (ip6forward_rt.ro_rt != NULL) {
 233                 rtfree(ip6forward_rt.ro_rt);
 234                 ip6forward_rt.ro_rt = NULL;
 235         }
 236
 237         return(-1);                     /* m would be freed in ip6_forward() */
 238 }
 239 #endif /* IP6_RTHDR0_ALLOWED */
 240