bsd/netinet6/in6_gif.c

   1 /*
   2  * Copyright (c) 2009-2012 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/in6_gif.c,v 1.2.2.3 2001/07/03 11:01:52 ume Exp $    */
  30 /*      $KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 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
  62 #include <sys/param.h>
  63 #include <sys/systm.h>
  64 #include <sys/socket.h>
  65 #include <sys/sockio.h>
  66 #include <sys/mbuf.h>
  67 #include <sys/errno.h>
  68 #include <sys/queue.h>
  69 #include <sys/syslog.h>
  70
  71 #include <sys/malloc.h>
  72 #include <sys/protosw.h>
  73
  74 #include <net/if.h>
  75 #include <net/route.h>
  76
  77 #include <netinet/in.h>
  78 #include <netinet/in_systm.h>
  79 #if INET
  80 #include <netinet/ip.h>
  81 #endif
  82 #include <netinet/ip_encap.h>
  83 #if INET6
  84 #include <netinet/ip6.h>
  85 #include <netinet6/ip6_var.h>
  86 #include <netinet6/in6_gif.h>
  87 #include <netinet6/in6_var.h>
  88 #endif
  89 #include <netinet/ip_ecn.h>
  90 #if INET6
  91 #include <netinet6/ip6_ecn.h>
  92 #endif
  93
  94 #include <net/if_gif.h>
  95
  96 #include <net/net_osdep.h>
  97
  98 static __inline__ void*
  99 _cast_non_const(const void * ptr) {
 100         union {
 101                 const void*             cval;
 102                 void*                   val;
 103         } ret;
 104
 105         ret.cval = ptr;
 106         return (ret.val);
 107 }
 108
 109 int
 110 in6_gif_output(
 111         struct ifnet *ifp,
 112         int family, /* family of the packet to be encapsulate. */
 113         struct mbuf *m,
 114         __unused struct rtentry *rt)
 115 {
 116         struct gif_softc *sc = ifnet_softc(ifp);
 117         struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
 118         struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)(void *)sc->gif_psrc;
 119         struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)(void *)sc->gif_pdst;
 120         struct ip6_hdr *ip6;
 121         int proto;
 122         u_int8_t itos, otos;
 123
 124         if (sin6_src == NULL || sin6_dst == NULL ||
 125             sin6_src->sin6_family != AF_INET6 ||
 126             sin6_dst->sin6_family != AF_INET6) {
 127                 m_freem(m);
 128                 return EAFNOSUPPORT;
 129         }
 130
 131         switch (family) {
 132 #if INET
 133         case AF_INET:
 134             {
 135                 struct ip *ip;
 136
 137                 proto = IPPROTO_IPV4;
 138                 if (mbuf_len(m) < sizeof(*ip)) {
 139                         m = m_pullup(m, sizeof(*ip));
 140                         if (!m)
 141                                 return ENOBUFS;
 142                 }
 143                 ip = mtod(m, struct ip *);
 144                 itos = ip->ip_tos;
 145                 break;
 146             }
 147 #endif
 148 #if INET6
 149         case AF_INET6:
 150             {
 151                 proto = IPPROTO_IPV6;
 152                 if (mbuf_len(m) < sizeof(*ip6)) {
 153                         m = m_pullup(m, sizeof(*ip6));
 154                         if (!m)
 155                                 return ENOBUFS;
 156                 }
 157                 ip6 = mtod(m, struct ip6_hdr *);
 158                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 159                 break;
 160             }
 161 #endif
 162         default:
 163 #if DEBUG
 164                 printf("in6_gif_output: warning: unknown family %d passed\n",
 165                         family);
 166 #endif
 167                 m_freem(m);
 168                 return EAFNOSUPPORT;
 169         }
 170
 171         /* prepend new IP header */
 172         M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
 173         if (m && mbuf_len(m) < sizeof(struct ip6_hdr))
 174                 m = m_pullup(m, sizeof(struct ip6_hdr));
 175         if (m == NULL) {
 176                 printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
 177                 return ENOBUFS;
 178         }
 179
 180         ip6 = mtod(m, struct ip6_hdr *);
 181         ip6->ip6_flow   = 0;
 182         ip6->ip6_vfc    &= ~IPV6_VERSION_MASK;
 183         ip6->ip6_vfc    |= IPV6_VERSION;
 184         ip6->ip6_plen   = htons((u_short)m->m_pkthdr.len);
 185         ip6->ip6_nxt    = proto;
 186         ip6->ip6_hlim   = ip6_gif_hlim;
 187         ip6->ip6_src    = sin6_src->sin6_addr;
 188         /* bidirectional configured tunnel mode */
 189         if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
 190                 ip6->ip6_dst = sin6_dst->sin6_addr;
 191         else  {
 192                 m_freem(m);
 193                 return ENETUNREACH;
 194         }
 195         ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
 196                        &otos, &itos);
 197         ip6->ip6_flow &= ~htonl(0xff << 20);
 198         ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
 199
 200         if (dst->sin6_family != sin6_dst->sin6_family ||
 201             !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr) ||
 202             (sc->gif_ro6.ro_rt != NULL &&
 203             (sc->gif_ro6.ro_rt->generation_id != route_generation ||
 204             sc->gif_ro6.ro_rt->rt_ifp == ifp))) {
 205                 /* cache route doesn't match or recursive route */
 206                 bzero(dst, sizeof(*dst));
 207                 dst->sin6_family = sin6_dst->sin6_family;
 208                 dst->sin6_len = sizeof(struct sockaddr_in6);
 209                 dst->sin6_addr = sin6_dst->sin6_addr;
 210                 if (sc->gif_ro6.ro_rt) {
 211                         rtfree(sc->gif_ro6.ro_rt);
 212                         sc->gif_ro6.ro_rt = NULL;
 213                 }
 214 #if 0
 215                 sc->gif_if.if_mtu = GIF_MTU;
 216 #endif
 217         }
 218
 219         if (sc->gif_ro6.ro_rt == NULL) {
 220                 rtalloc((struct route *)&sc->gif_ro6);
 221                 if (sc->gif_ro6.ro_rt == NULL) {
 222                         m_freem(m);
 223                         return ENETUNREACH;
 224                 }
 225                 RT_LOCK(sc->gif_ro6.ro_rt);
 226                 /* if it constitutes infinite encapsulation, punt. */
 227                 if (sc->gif_ro6.ro_rt->rt_ifp == ifp) {
 228                         RT_UNLOCK(sc->gif_ro6.ro_rt);
 229                         m_freem(m);
 230                         return ENETUNREACH;     /*XXX*/
 231                 }
 232 #if 0
 233                 ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
 234                         - sizeof(struct ip6_hdr);
 235 #endif
 236                 RT_UNLOCK(sc->gif_ro6.ro_rt);
 237         }
 238
 239 #if IPV6_MINMTU
 240         /*
 241          * force fragmentation to minimum MTU, to avoid path MTU discovery.
 242          * it is too painful to ask for resend of inner packet, to achieve
 243          * path MTU discovery for encapsulated packets.
 244          */
 245         return(ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL));
 246 #else
 247         return(ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL));
 248 #endif
 249 }
 250
 251 int in6_gif_input(struct mbuf **mp, int *offp, int proto)
 252 {
 253         struct mbuf *m = *mp;
 254         struct ifnet *gifp = NULL;
 255         struct ip6_hdr *ip6;
 256         int af = 0;
 257         u_int32_t otos;
 258
 259         ip6 = mtod(m, struct ip6_hdr *);
 260
 261         gifp = ((struct gif_softc*)encap_getarg(m))->gif_if;
 262
 263         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 264                 m_freem(m);
 265                 ip6stat.ip6s_nogif++;
 266                 return IPPROTO_DONE;
 267         }
 268
 269         otos = ip6->ip6_flow;
 270         m_adj(m, *offp);
 271
 272         switch (proto) {
 273 #if INET
 274         case IPPROTO_IPV4:
 275             {
 276                 struct ip *ip;
 277                 u_int8_t otos8;
 278                 af = AF_INET;
 279                 otos8 = (ntohl(otos) >> 20) & 0xff;
 280                 if (mbuf_len(m) < sizeof(*ip)) {
 281                         m = m_pullup(m, sizeof(*ip));
 282                         if (!m)
 283                                 return IPPROTO_DONE;
 284                 }
 285                 ip = mtod(m, struct ip *);
 286                 if (gifp->if_flags & IFF_LINK1)
 287                         ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
 288                 else
 289                         ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
 290                 break;
 291             }
 292 #endif /* INET */
 293 #if INET6
 294         case IPPROTO_IPV6:
 295             {
 296                 af = AF_INET6;
 297                 if (mbuf_len(m) < sizeof(*ip6)) {
 298                         m = m_pullup(m, sizeof(*ip6));
 299                         if (!m)
 300                                 return IPPROTO_DONE;
 301                 }
 302                 ip6 = mtod(m, struct ip6_hdr *);
 303                 if (gifp->if_flags & IFF_LINK1)
 304                         ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6->ip6_flow);
 305                 else
 306                         ip6_ecn_egress(ECN_NOCARE, &otos, &ip6->ip6_flow);
 307                 break;
 308             }
 309 #endif
 310         default:
 311                 ip6stat.ip6s_nogif++;
 312                 m_freem(m);
 313                 return IPPROTO_DONE;
 314         }
 315
 316         if (m->m_pkthdr.rcvif)  /* replace the rcvif by gifp for ifnet_input to route it correctly */
 317                 m->m_pkthdr.rcvif = gifp;
 318
 319         ifnet_input(gifp, m, NULL);
 320         return IPPROTO_DONE;
 321 }
 322
 323 /*
 324  * validate outer address.
 325  */
 326 static int
 327 gif_validate6(
 328         const struct ip6_hdr *ip6,
 329         struct gif_softc *sc,
 330         struct ifnet *ifp)
 331 {
 332         struct sockaddr_in6 *src, *dst;
 333
 334         src = (struct sockaddr_in6 *)(void *)sc->gif_psrc;
 335         dst = (struct sockaddr_in6 *)(void *)sc->gif_pdst;
 336
 337         /*
 338          * Check for address match.  Note that the check is for an incoming
 339          * packet.  We should compare the *source* address in our configuration
 340          * and the *destination* address of the packet, and vice versa.
 341          */
 342         if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
 343             !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
 344                 return 0;
 345
 346         /* martian filters on outer source - done in ip6_input */
 347
 348         /* ingress filters on outer source */
 349         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 && ifp) {
 350                 struct sockaddr_in6 sin6;
 351                 struct rtentry *rt;
 352
 353                 bzero(&sin6, sizeof(sin6));
 354                 sin6.sin6_family = AF_INET6;
 355                 sin6.sin6_len = sizeof(struct sockaddr_in6);
 356                 sin6.sin6_addr = ip6->ip6_src;
 357
 358                 rt = rtalloc1((struct sockaddr *)&sin6, 0, 0);
 359                 if (rt != NULL)
 360                         RT_LOCK(rt);
 361                 if (!rt || rt->rt_ifp != ifp) {
 362 #if 0
 363                         log(LOG_WARNING, "%s: packet from %s dropped "
 364                             "due to ingress filter\n", if_name(&sc->gif_if),
 365                             ip6_sprintf(&sin6.sin6_addr));
 366 #endif
 367                         if (rt != NULL) {
 368                                 RT_UNLOCK(rt);
 369                                 rtfree(rt);
 370                         }
 371                         return 0;
 372                 }
 373                 RT_UNLOCK(rt);
 374                 rtfree(rt);
 375         }
 376
 377         return 128 * 2;
 378 }
 379
 380 /*
 381  * we know that we are in IFF_UP, outer address available, and outer family
 382  * matched the physical addr family.  see gif_encapcheck().
 383  * sanity check for arg should have been done in the caller.
 384  */
 385 int
 386 gif_encapcheck6(
 387         const struct mbuf *m,
 388         __unused int off,
 389         __unused int proto,
 390         void *arg)
 391 {
 392         struct ip6_hdr ip6;
 393         struct gif_softc *sc;
 394         struct ifnet *ifp;
 395
 396         /* sanity check done in caller */
 397         sc = (struct gif_softc *)arg;
 398
 399         mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof(ip6), &ip6);
 400         ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
 401
 402         return gif_validate6(&ip6, sc, ifp);
 403 }