bsd/netinet6/route6.c

   1 /*
   2  * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*      $FreeBSD: src/sys/netinet6/route6.c,v 1.1.2.3 2001/07/03 11:01:55 ume Exp $     */
  30 /*      $KAME: route6.c,v 1.24 2001/03/14 03:07:05 itojun Exp $ */
  31
  32 /*
  33  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  34  * All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. Neither the name of the project nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/mbuf.h>
  63 #include <sys/socket.h>
  64 #include <sys/queue.h>
  65 #include <string.h>
  66
  67 #include <net/if.h>
  68 #include <net/route.h>
  69
  70 #include <netinet/in.h>
  71 #include <netinet6/in6_var.h>
  72 #include <netinet/ip6.h>
  73 #include <netinet6/ip6_var.h>
  74
  75 #include <netinet/icmp6.h>
  76
  77 #if IP6_RTHDR0_ALLOWED
  78 static int ip6_rthdr0(struct mbuf *, struct ip6_hdr *,
  79     struct ip6_rthdr0 *);
  80 #endif /* IP6_RTHDR0_ALLOWED */
  81
  82 int
  83 route6_input(struct mbuf **mp, int *offp, int proto)
  84 {
  85 #pragma unused(proto)
  86         struct ip6_hdr *ip6;
  87         struct mbuf *m = *mp;
  88         struct ip6_rthdr *rh;
  89         int off = *offp, rhlen;
  90         struct ip6aux *ip6a;
  91
  92         ip6a = ip6_findaux(m);
  93         if (ip6a) {
  94                 /* XXX reject home-address option before rthdr */
  95                 if (ip6a->ip6a_flags & IP6A_SWAP) {
  96                         ip6stat.ip6s_badoptions++;
  97                         m_freem(m);
  98                         return IPPROTO_DONE;
  99                 }
 100         }
 101
 102 #ifndef PULLDOWN_TEST
 103         IP6_EXTHDR_CHECK(m, off, sizeof(*rh), return IPPROTO_DONE);
 104         ip6 = mtod(m, struct ip6_hdr *);
 105         rh = (struct ip6_rthdr *)((caddr_t)ip6 + off);
 106 #else
 107         ip6 = mtod(m, struct ip6_hdr *);
 108         IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, sizeof(*rh));
 109         if (rh == NULL) {
 110                 ip6stat.ip6s_tooshort++;
 111                 return IPPROTO_DONE;
 112         }
 113 #endif
 114
 115         switch (rh->ip6r_type) {
 116 #if IP6_RTHDR0_ALLOWED
 117         case IPV6_RTHDR_TYPE_0:
 118                 rhlen = (rh->ip6r_len + 1) << 3;
 119 #ifndef PULLDOWN_TEST
 120                 /*
 121                  * note on option length:
 122                  * due to IP6_EXTHDR_CHECK assumption, we cannot handle
 123                  * very big routing header (max rhlen == 2048).
 124                  */
 125                 IP6_EXTHDR_CHECK(m, off, rhlen, return IPPROTO_DONE);
 126 #else
 127                 /*
 128                  * note on option length:
 129                  * maximum rhlen: 2048
 130                  * max mbuf m_pulldown can handle: MCLBYTES == usually 2048
 131                  * so, here we are assuming that m_pulldown can handle
 132                  * rhlen == 2048 case.  this may not be a good thing to
 133                  * assume - we may want to avoid pulling it up altogether.
 134                  */
 135                 IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, rhlen);
 136                 if (rh == NULL) {
 137                         ip6stat.ip6s_tooshort++;
 138                         return IPPROTO_DONE;
 139                 }
 140 #endif
 141                 if (ip6_rthdr0(m, ip6, (struct ip6_rthdr0 *)rh))
 142                         return(IPPROTO_DONE);
 143                 break;
 144 #endif /* IP6_RTHDR0_ALLOWED */
 145         default:
 146                 /* unknown routing type */
 147                 if (rh->ip6r_segleft == 0) {
 148                         rhlen = (rh->ip6r_len + 1) << 3;
 149                         break;  /* Final dst. Just ignore the header. */
 150                 }
 151                 ip6stat.ip6s_badoptions++;
 152                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 153                             (caddr_t)&rh->ip6r_type - (caddr_t)ip6);
 154                 return(IPPROTO_DONE);
 155         }
 156
 157         *offp += rhlen;
 158         return(rh->ip6r_nxt);
 159 }
 160
 161 #if IP6_RTHDR0_ALLOWED
 162 /*
 163  * Type0 routing header processing
 164  *
 165  * RFC2292 backward compatibility warning: no support for strict/loose bitmap,
 166  * as it was dropped between RFC1883 and RFC2460.
 167  */
 168 static int
 169 ip6_rthdr0(m, ip6, rh0)
 170         struct mbuf *m;
 171         struct ip6_hdr *ip6;
 172         struct ip6_rthdr0 *rh0;
 173 {
 174         int addrs, index;
 175         struct in6_addr *nextaddr, tmpaddr, ia6 = NULL;
 176         struct route_in6 ip6forward_rt;
 177
 178         if (rh0->ip6r0_segleft == 0)
 179                 return(0);
 180
 181         if (rh0->ip6r0_len % 2
 182 #if COMPAT_RFC1883
 183             || rh0->ip6r0_len > 46
 184 #endif
 185                 ) {
 186                 /*
 187                  * Type 0 routing header can't contain more than 23 addresses.
 188                  * RFC 2462: this limitation was removed since strict/loose
 189                  * bitmap field was deleted.
 190                  */
 191                 ip6stat.ip6s_badoptions++;
 192                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 193                             (caddr_t)&rh0->ip6r0_len - (caddr_t)ip6);
 194                 return (-1);
 195         }
 196
 197         if ((addrs = rh0->ip6r0_len / 2) < rh0->ip6r0_segleft) {
 198                 ip6stat.ip6s_badoptions++;
 199                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 200                             (caddr_t)&rh0->ip6r0_segleft - (caddr_t)ip6);
 201                 return (-1);
 202         }
 203
 204         index = addrs - rh0->ip6r0_segleft;
 205         rh0->ip6r0_segleft--;
 206         /* note that ip6r0_addr does not exist in RFC2292bis */
 207         nextaddr = rh0->ip6r0_addr + index;
 208
 209         /*
 210          * reject invalid addresses.  be proactive about malicious use of
 211          * IPv4 mapped/compat address.
 212          * XXX need more checks?
 213          */
 214         if (IN6_IS_ADDR_MULTICAST(nextaddr) ||
 215             IN6_IS_ADDR_UNSPECIFIED(nextaddr) ||
 216             IN6_IS_ADDR_V4MAPPED(nextaddr) ||
 217             IN6_IS_ADDR_V4COMPAT(nextaddr)) {
 218                 ip6stat.ip6s_badoptions++;
 219                 m_freem(m);
 220                 return (-1);
 221         }
 222         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 223             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst) ||
 224             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst) ||
 225             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
 226                 ip6stat.ip6s_badoptions++;
 227                 m_freem(m);
 228                 return (-1);
 229         }
 230
 231         /*
 232          * Determine the scope zone of the next hop, based on the interface
 233          * of the current hop. [RFC4007, Section 9]
 234          * Then disambiguate the scope zone for the next hop (if necessary).
 235          */
 236         if ((ia6 = ip6_getdstifaddr(m)) == NULL)
 237                 goto bad;
 238         if (in6_setscope(nextaddr, ia6->ia_ifp, NULL) != 0) {
 239                 ip6stat.ip6s_badscope++;
 240                 IFA_REMREF(&ia6->ia_ifa);
 241                 ia6 = NULL;
 242                 goto bad;
 243         }
 244         IFA_REMREF(&ia6->ia_ifa);
 245         ia6 = NULL;
 246
 247         /*
 248          * Swap the IPv6 destination address and nextaddr. Forward the packet.
 249          */
 250         tmpaddr = *nextaddr;
 251         *nextaddr = ip6->ip6_dst;
 252         in6_clearscope(nextaddr); /* XXX */
 253         ip6->ip6_dst = tmpaddr;
 254         if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
 255                 ip6->ip6_dst.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
 256
 257         /*
 258          * Don't use the globally cached route to forward packet having
 259          * Type 0 routing header(s); instead, do an explicit lookup using
 260          * a local route entry variable, in case the next address in the
 261          * packet is bogus (which would otherwise unnecessarily invalidate
 262          * the globally cached route).
 263          */
 264         bzero(&ip6forward_rt, sizeof (ip6forward_rt));
 265
 266 #if COMPAT_RFC1883
 267         if (rh0->ip6r0_slmap[index / 8] & (1 << (7 - (index % 8))))
 268                 ip6_forward(m, &ip6forward_rt, IPV6_SRCRT_NEIGHBOR, 0);
 269         else
 270                 ip6_forward(m, &ip6forward_rt, IPV6_SRCRT_NOTNEIGHBOR, 0);
 271 #else
 272         ip6_forward(m, &ip6forward_rt, 1, 0);
 273 #endif
 274
 275         /* Release reference to the looked up route */
 276         if (ip6forward_rt.ro_rt != NULL) {
 277                 rtfree(ip6forward_rt.ro_rt);
 278                 ip6forward_rt.ro_rt = NULL;
 279         }
 280
 281         return(-1);                     /* m would be freed in ip6_forward() */
 282 }
 283 #endif /* IP6_RTHDR0_ALLOWED */
 284