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
  38 #include <net/if.h>
  39
  40 #include <netinet/in.h>
  41 #include <netinet6/in6_var.h>
  42 #include <netinet/ip6.h>
  43 #include <netinet6/ip6_var.h>
  44
  45 #include <netinet/icmp6.h>
  46
  47 static int ip6_rthdr0 __P((struct mbuf *, struct ip6_hdr *,
  48     struct ip6_rthdr0 *));
  49
  50 int
  51 route6_input(mp, offp, proto)
  52         struct mbuf **mp;
  53         int *offp, proto;       /* proto is unused */
  54 {
  55         struct ip6_hdr *ip6;
  56         struct mbuf *m = *mp;
  57         struct ip6_rthdr *rh;
  58         int off = *offp, rhlen;
  59         struct mbuf *n;
  60
  61         n = ip6_findaux(m);
  62         if (n) {
  63                 struct ip6aux *ip6a = mtod(n, struct ip6aux *);
  64                 /* XXX reject home-address option before rthdr */
  65                 if (ip6a->ip6a_flags & IP6A_SWAP) {
  66                         ip6stat.ip6s_badoptions++;
  67                         m_freem(m);
  68                         return IPPROTO_DONE;
  69                 }
  70         }
  71
  72 #ifndef PULLDOWN_TEST
  73         IP6_EXTHDR_CHECK(m, off, sizeof(*rh), IPPROTO_DONE);
  74         ip6 = mtod(m, struct ip6_hdr *);
  75         rh = (struct ip6_rthdr *)((caddr_t)ip6 + off);
  76 #else
  77         ip6 = mtod(m, struct ip6_hdr *);
  78         IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, sizeof(*rh));
  79         if (rh == NULL) {
  80                 ip6stat.ip6s_tooshort++;
  81                 return IPPROTO_DONE;
  82         }
  83 #endif
  84
  85         switch (rh->ip6r_type) {
  86         case IPV6_RTHDR_TYPE_0:
  87                 rhlen = (rh->ip6r_len + 1) << 3;
  88 #ifndef PULLDOWN_TEST
  89                 /*
  90                  * note on option length:
  91                  * due to IP6_EXTHDR_CHECK assumption, we cannot handle
  92                  * very big routing header (max rhlen == 2048).
  93                  */
  94                 IP6_EXTHDR_CHECK(m, off, rhlen, IPPROTO_DONE);
  95 #else
  96                 /*
  97                  * note on option length:
  98                  * maximum rhlen: 2048
  99                  * max mbuf m_pulldown can handle: MCLBYTES == usually 2048
 100                  * so, here we are assuming that m_pulldown can handle
 101                  * rhlen == 2048 case.  this may not be a good thing to
 102                  * assume - we may want to avoid pulling it up altogether.
 103                  */
 104                 IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, rhlen);
 105                 if (rh == NULL) {
 106                         ip6stat.ip6s_tooshort++;
 107                         return IPPROTO_DONE;
 108                 }
 109 #endif
 110                 if (ip6_rthdr0(m, ip6, (struct ip6_rthdr0 *)rh))
 111                         return(IPPROTO_DONE);
 112                 break;
 113         default:
 114                 /* unknown routing type */
 115                 if (rh->ip6r_segleft == 0) {
 116                         rhlen = (rh->ip6r_len + 1) << 3;
 117                         break;  /* Final dst. Just ignore the header. */
 118                 }
 119                 ip6stat.ip6s_badoptions++;
 120                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 121                             (caddr_t)&rh->ip6r_type - (caddr_t)ip6);
 122                 return(IPPROTO_DONE);
 123         }
 124
 125         *offp += rhlen;
 126         return(rh->ip6r_nxt);
 127 }
 128
 129 /*
 130  * Type0 routing header processing
 131  *
 132  * RFC2292 backward compatibility warning: no support for strict/loose bitmap,
 133  * as it was dropped between RFC1883 and RFC2460.
 134  */
 135 static int
 136 ip6_rthdr0(m, ip6, rh0)
 137         struct mbuf *m;
 138         struct ip6_hdr *ip6;
 139         struct ip6_rthdr0 *rh0;
 140 {
 141         int addrs, index;
 142         struct in6_addr *nextaddr, tmpaddr;
 143
 144         if (rh0->ip6r0_segleft == 0)
 145                 return(0);
 146
 147         if (rh0->ip6r0_len % 2
 148 #if COMPAT_RFC1883
 149             || rh0->ip6r0_len > 46
 150 #endif
 151                 ) {
 152                 /*
 153                  * Type 0 routing header can't contain more than 23 addresses.
 154                  * RFC 2462: this limitation was removed since stict/loose
 155                  * bitmap field was deleted.
 156                  */
 157                 ip6stat.ip6s_badoptions++;
 158                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 159                             (caddr_t)&rh0->ip6r0_len - (caddr_t)ip6);
 160                 return(-1);
 161         }
 162
 163         if ((addrs = rh0->ip6r0_len / 2) < rh0->ip6r0_segleft) {
 164                 ip6stat.ip6s_badoptions++;
 165                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 166                             (caddr_t)&rh0->ip6r0_segleft - (caddr_t)ip6);
 167                 return(-1);
 168         }
 169
 170         index = addrs - rh0->ip6r0_segleft;
 171         rh0->ip6r0_segleft--;
 172         /* note that ip6r0_addr does not exist in RFC2292bis */
 173         nextaddr = rh0->ip6r0_addr + index;
 174
 175         /*
 176          * reject invalid addresses.  be proactive about malicious use of
 177          * IPv4 mapped/compat address.
 178          * XXX need more checks?
 179          */
 180         if (IN6_IS_ADDR_MULTICAST(nextaddr) ||
 181             IN6_IS_ADDR_UNSPECIFIED(nextaddr) ||
 182             IN6_IS_ADDR_V4MAPPED(nextaddr) ||
 183             IN6_IS_ADDR_V4COMPAT(nextaddr)) {
 184                 ip6stat.ip6s_badoptions++;
 185                 m_freem(m);
 186                 return(-1);
 187         }
 188         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 189             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst) ||
 190             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst) ||
 191             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
 192                 ip6stat.ip6s_badoptions++;
 193                 m_freem(m);
 194                 return(-1);
 195         }
 196
 197         /*
 198          * Swap the IPv6 destination address and nextaddr. Forward the packet.
 199          */
 200         tmpaddr = *nextaddr;
 201         *nextaddr = ip6->ip6_dst;
 202         if (IN6_IS_ADDR_LINKLOCAL(nextaddr))
 203                 nextaddr->s6_addr16[1] = 0;
 204         ip6->ip6_dst = tmpaddr;
 205         if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
 206                 ip6->ip6_dst.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
 207
 208 #if COMPAT_RFC1883
 209         if (rh0->ip6r0_slmap[index / 8] & (1 << (7 - (index % 8))))
 210                 ip6_forward(m, IPV6_SRCRT_NEIGHBOR);
 211         else
 212                 ip6_forward(m, IPV6_SRCRT_NOTNEIGHBOR);
 213 #else
 214         ip6_forward(m, 1);
 215 #endif
 216
 217         return(-1);                     /* m would be freed in ip6_forward() */
 218 }