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 1.9 2007/05/07 13:00:16 hasso 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 #if 0
  53 static int ip6_rthdr0 (struct mbuf *, struct ip6_hdr *,
  54     struct ip6_rthdr0 *);
  55 #endif
  56
  57 int
  58 route6_input(struct mbuf **mp, int *offp, int proto) /* proto is unused */
  59 {
  60         struct ip6_hdr *ip6;
  61         struct mbuf *m = *mp;
  62         struct ip6_rthdr *rh;
  63         int off = *offp, rhlen;
  64
  65 #ifndef PULLDOWN_TEST
  66         IP6_EXTHDR_CHECK(m, off, sizeof(*rh), IPPROTO_DONE);
  67         ip6 = mtod(m, struct ip6_hdr *);
  68         rh = (struct ip6_rthdr *)((caddr_t)ip6 + off);
  69 #else
  70         ip6 = mtod(m, struct ip6_hdr *);
  71         IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, sizeof(*rh));
  72         if (rh == NULL) {
  73                 ip6stat.ip6s_tooshort++;
  74                 return IPPROTO_DONE;
  75         }
  76 #endif
  77
  78         switch (rh->ip6r_type) {
  79 #if 0
  80         /*
  81          * See http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf
  82          * for why IPV6_RTHDR_TYPE_0 is baned here.
  83          *
  84          * We return ICMPv6 parameter problem so that innocent people
  85          * (not an attacker) would notice about the use of IPV6_RTHDR_TYPE_0.
  86          * Since there's no amplification, and ICMPv6 error will be rate-
  87          * controlled, it shouldn't cause any problem.
  88          * If you are concerned about this, you may want to use the following
  89          * code fragment:
  90          *
  91          * case IPV6_RTHDR_TYPE_0:
  92          *      m_freem(m);
  93          *      return (IPPROTO_DONE);
  94          */
  95         case IPV6_RTHDR_TYPE_0:
  96                 rhlen = (rh->ip6r_len + 1) << 3;
  97 #ifndef PULLDOWN_TEST
  98                 /*
  99                  * note on option length:
 100                  * due to IP6_EXTHDR_CHECK assumption, we cannot handle
 101                  * very big routing header (max rhlen == 2048).
 102                  */
 103                 IP6_EXTHDR_CHECK(m, off, rhlen, IPPROTO_DONE);
 104 #else
 105                 /*
 106                  * note on option length:
 107                  * maximum rhlen: 2048
 108                  * max mbuf m_pulldown can handle: MCLBYTES == usually 2048
 109                  * so, here we are assuming that m_pulldown can handle
 110                  * rhlen == 2048 case.  this may not be a good thing to
 111                  * assume - we may want to avoid pulling it up altogether.
 112                  */
 113                 IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, rhlen);
 114                 if (rh == NULL) {
 115                         ip6stat.ip6s_tooshort++;
 116                         return IPPROTO_DONE;
 117                 }
 118 #endif
 119                 if (ip6_rthdr0(m, ip6, (struct ip6_rthdr0 *)rh))
 120                         return (IPPROTO_DONE);
 121                 break;
 122 #endif
 123         default:
 124                 /* unknown routing type */
 125                 if (rh->ip6r_segleft == 0) {
 126                         rhlen = (rh->ip6r_len + 1) << 3;
 127                         break;  /* Final dst. Just ignore the header. */
 128                 }
 129                 ip6stat.ip6s_badoptions++;
 130                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 131                             (caddr_t)&rh->ip6r_type - (caddr_t)ip6);
 132                 return (IPPROTO_DONE);
 133         }
 134
 135         *offp += rhlen;
 136         return (rh->ip6r_nxt);
 137 }
 138
 139 #if 0
 140 /*
 141  * Type0 routing header processing
 142  *
 143  * RFC2292 backward compatibility warning: no support for strict/loose bitmap,
 144  * as it was dropped between RFC1883 and RFC2460.
 145  */
 146 static int
 147 ip6_rthdr0(struct mbuf *m, struct ip6_hdr *ip6, struct ip6_rthdr0 *rh0)
 148 {
 149         int addrs, index;
 150         struct in6_addr *nextaddr, tmpaddr;
 151
 152         if (rh0->ip6r0_segleft == 0)
 153                 return (0);
 154
 155         if (rh0->ip6r0_len % 2
 156 #ifdef COMPAT_RFC1883
 157             || rh0->ip6r0_len > 46
 158 #endif
 159                 ) {
 160                 /*
 161                  * Type 0 routing header can't contain more than 23 addresses.
 162                  * RFC 2462: this limitation was removed since strict/loose
 163                  * bitmap field was deleted.
 164                  */
 165                 ip6stat.ip6s_badoptions++;
 166                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 167                             (caddr_t)&rh0->ip6r0_len - (caddr_t)ip6);
 168                 return (-1);
 169         }
 170
 171         if ((addrs = rh0->ip6r0_len / 2) < rh0->ip6r0_segleft) {
 172                 ip6stat.ip6s_badoptions++;
 173                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
 174                             (caddr_t)&rh0->ip6r0_segleft - (caddr_t)ip6);
 175                 return (-1);
 176         }
 177
 178         index = addrs - rh0->ip6r0_segleft;
 179         rh0->ip6r0_segleft--;
 180         /* note that ip6r0_addr does not exist in RFC2292bis */
 181         nextaddr = rh0->ip6r0_addr + index;
 182
 183         /*
 184          * reject invalid addresses.  be proactive about malicious use of
 185          * IPv4 mapped/compat address.
 186          * XXX need more checks?
 187          */
 188         if (IN6_IS_ADDR_MULTICAST(nextaddr) ||
 189             IN6_IS_ADDR_UNSPECIFIED(nextaddr) ||
 190             IN6_IS_ADDR_V4MAPPED(nextaddr) ||
 191             IN6_IS_ADDR_V4COMPAT(nextaddr)) {
 192                 ip6stat.ip6s_badoptions++;
 193                 m_freem(m);
 194                 return (-1);
 195         }
 196         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 197             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst) ||
 198             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst) ||
 199             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
 200                 ip6stat.ip6s_badoptions++;
 201                 m_freem(m);
 202                 return (-1);
 203         }
 204
 205         /*
 206          * Swap the IPv6 destination address and nextaddr. Forward the packet.
 207          */
 208         tmpaddr = *nextaddr;
 209         *nextaddr = ip6->ip6_dst;
 210         if (IN6_IS_ADDR_LINKLOCAL(nextaddr))
 211                 nextaddr->s6_addr16[1] = 0;
 212         ip6->ip6_dst = tmpaddr;
 213         if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
 214                 ip6->ip6_dst.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
 215
 216 #ifdef COMPAT_RFC1883
 217         if (rh0->ip6r0_slmap[index / 8] & (1 << (7 - (index % 8))))
 218                 ip6_forward(m, IPV6_SRCRT_NEIGHBOR);
 219         else
 220                 ip6_forward(m, IPV6_SRCRT_NOTNEIGHBOR);
 221 #else
 222         ip6_forward(m, 1);
 223 #endif
 224
 225         return (-1);                    /* m would be freed in ip6_forward() */
 226 }
 227 #endif