bsd/netinet/in_gif.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*      $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ */
  24
  25 /*
  26  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  27  * All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. Neither the name of the project nor the names of its contributors
  38  *    may be used to endorse or promote products derived from this software
  39  *    without specific prior written permission.
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  */
  53
  54
  55 #include <sys/param.h>
  56 #include <sys/systm.h>
  57 #include <sys/socket.h>
  58 #include <sys/sockio.h>
  59 #include <sys/mbuf.h>
  60 #include <sys/errno.h>
  61 #include <sys/kernel.h>
  62 #include <sys/sysctl.h>
  63
  64 #include <sys/malloc.h>
  65
  66 #include <net/if.h>
  67 #include <net/route.h>
  68
  69 #include <netinet/in.h>
  70 #include <netinet/in_systm.h>
  71 #include <netinet/ip.h>
  72 #include <netinet/ip_var.h>
  73 #include <netinet/in_gif.h>
  74 #include <netinet/in_var.h>
  75 #include <netinet/ip_encap.h>
  76 #include <netinet/ip_ecn.h>
  77
  78 #if INET6
  79 #include <netinet/ip6.h>
  80 #endif
  81
  82 #if MROUTING
  83 #include <netinet/ip_mroute.h>
  84 #endif /* MROUTING */
  85
  86 #include <net/if_gif.h>
  87
  88 #include <net/net_osdep.h>
  89
  90 int ip_gif_ttl = GIF_TTL;
  91 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
  92         &ip_gif_ttl,    0, "");
  93
  94 int
  95 in_gif_output(
  96         struct ifnet    *ifp,
  97         int             family,
  98         struct mbuf     *m,
  99         struct rtentry *rt)
 100 {
 101         struct gif_softc *sc = (struct gif_softc*)ifp;
 102         struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
 103         struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
 104         struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
 105         struct ip iphdr;        /* capsule IP header, host byte ordered */
 106         int proto, error;
 107         u_int8_t tos;
 108
 109         if (sin_src == NULL || sin_dst == NULL ||
 110             sin_src->sin_family != AF_INET ||
 111             sin_dst->sin_family != AF_INET) {
 112                 m_freem(m);
 113                 return EAFNOSUPPORT;
 114         }
 115
 116         switch (family) {
 117 #if INET
 118         case AF_INET:
 119             {
 120                 struct ip *ip;
 121
 122                 proto = IPPROTO_IPV4;
 123                 if (m->m_len < sizeof(*ip)) {
 124                         m = m_pullup(m, sizeof(*ip));
 125                         if (!m)
 126                                 return ENOBUFS;
 127                 }
 128                 ip = mtod(m, struct ip *);
 129                 tos = ip->ip_tos;
 130                 break;
 131             }
 132 #endif /*INET*/
 133 #if INET6
 134         case AF_INET6:
 135             {
 136                 struct ip6_hdr *ip6;
 137                 proto = IPPROTO_IPV6;
 138                 if (m->m_len < sizeof(*ip6)) {
 139                         m = m_pullup(m, sizeof(*ip6));
 140                         if (!m)
 141                                 return ENOBUFS;
 142                 }
 143                 ip6 = mtod(m, struct ip6_hdr *);
 144                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 145                 break;
 146             }
 147 #endif /*INET6*/
 148         default:
 149 #if DEBUG
 150                 printf("in_gif_output: warning: unknown family %d passed\n",
 151                         family);
 152 #endif
 153                 m_freem(m);
 154                 return EAFNOSUPPORT;
 155         }
 156
 157         bzero(&iphdr, sizeof(iphdr));
 158         iphdr.ip_src = sin_src->sin_addr;
 159         /* bidirectional configured tunnel mode */
 160         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 161                 iphdr.ip_dst = sin_dst->sin_addr;
 162         else {
 163                 m_freem(m);
 164                 return ENETUNREACH;
 165         }
 166         iphdr.ip_p = proto;
 167         /* version will be set in ip_output() */
 168         iphdr.ip_ttl = ip_gif_ttl;
 169         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
 170         if (ifp->if_flags & IFF_LINK1)
 171                 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
 172         else
 173                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 174
 175         /* prepend new IP header */
 176         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 177         if (m && m->m_len < sizeof(struct ip))
 178                 m = m_pullup(m, sizeof(struct ip));
 179         if (m == NULL) {
 180                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 181                 return ENOBUFS;
 182         }
 183         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 184
 185         if (dst->sin_family != sin_dst->sin_family ||
 186             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
 187                 /* cache route doesn't match */
 188                 dst->sin_family = sin_dst->sin_family;
 189                 dst->sin_len = sizeof(struct sockaddr_in);
 190                 dst->sin_addr = sin_dst->sin_addr;
 191                 if (sc->gif_ro.ro_rt) {
 192                         rtfree(sc->gif_ro.ro_rt);
 193                         sc->gif_ro.ro_rt = NULL;
 194                 }
 195 #if 0
 196                 sc->gif_if.if_mtu = GIF_MTU;
 197 #endif
 198         }
 199
 200         if (sc->gif_ro.ro_rt == NULL) {
 201                 rtalloc(&sc->gif_ro);
 202                 if (sc->gif_ro.ro_rt == NULL) {
 203                         m_freem(m);
 204                         return ENETUNREACH;
 205                 }
 206
 207                 /* if it constitutes infinite encapsulation, punt. */
 208                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 209                         m_freem(m);
 210                         return ENETUNREACH;     /*XXX*/
 211                 }
 212 #if 0
 213                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 214                         - sizeof(struct ip);
 215 #endif
 216         }
 217
 218         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL);
 219         return(error);
 220 }
 221
 222 void
 223 in_gif_input(m, off)
 224         struct mbuf *m;
 225         int off;
 226 {
 227         struct ifnet *gifp = NULL;
 228         struct ip *ip;
 229         int i, af, proto;
 230         u_int8_t otos;
 231
 232         ip = mtod(m, struct ip *);
 233         proto = ip->ip_p;
 234
 235
 236         gifp = (struct ifnet *)encap_getarg(m);
 237
 238         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 239                 m_freem(m);
 240                 ipstat.ips_nogif++;
 241                 return;
 242         }
 243
 244         otos = ip->ip_tos;
 245         m_adj(m, off);
 246
 247         switch (proto) {
 248 #if INET
 249         case IPPROTO_IPV4:
 250             {
 251                 struct ip *ip;
 252                 af = AF_INET;
 253                 if (m->m_len < sizeof(*ip)) {
 254                         m = m_pullup(m, sizeof(*ip));
 255                         if (!m)
 256                                 return;
 257                 }
 258                 ip = mtod(m, struct ip *);
 259                 if (gifp->if_flags & IFF_LINK1)
 260                         ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
 261                 else
 262                         ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 263                 break;
 264             }
 265 #endif
 266 #if INET6
 267         case IPPROTO_IPV6:
 268             {
 269                 struct ip6_hdr *ip6;
 270                 u_int8_t itos;
 271                 af = AF_INET6;
 272                 if (m->m_len < sizeof(*ip6)) {
 273                         m = m_pullup(m, sizeof(*ip6));
 274                         if (!m)
 275                                 return;
 276                 }
 277                 ip6 = mtod(m, struct ip6_hdr *);
 278                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 279                 if (gifp->if_flags & IFF_LINK1)
 280                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 281                 else
 282                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 283                 ip6->ip6_flow &= ~htonl(0xff << 20);
 284                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 285                 break;
 286             }
 287 #endif /* INET6 */
 288         default:
 289                 ipstat.ips_nogif++;
 290                 m_freem(m);
 291                 return;
 292         }
 293 #ifdef __APPLE__
 294         /* Should we free m if dlil_input returns an error? */
 295         if (m->m_pkthdr.rcvif)  /* replace the rcvif by gifp for dlil to route it correctly */
 296                 m->m_pkthdr.rcvif = gifp;
 297         dlil_input_packet(gifp, m, NULL);
 298 #else
 299         gif_input(m, af, gifp);
 300 #endif
 301         return;
 302 }
 303
 304 /*
 305  * we know that we are in IFF_UP, outer address available, and outer family
 306  * matched the physical addr family.  see gif_encapcheck().
 307  */
 308 int
 309 gif_encapcheck4(m, off, proto, arg)
 310         const struct mbuf *m;
 311         int off;
 312         int proto;
 313         void *arg;
 314 {
 315         struct ip ip;
 316         struct gif_softc *sc;
 317         struct sockaddr_in *src, *dst;
 318         int addrmatch;
 319         struct in_ifaddr *ia4;
 320
 321         /* sanity check done in caller */
 322         sc = (struct gif_softc *)arg;
 323         src = (struct sockaddr_in *)sc->gif_psrc;
 324         dst = (struct sockaddr_in *)sc->gif_pdst;
 325
 326         /* LINTED const cast */
 327         m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
 328
 329         /* check for address match */
 330         addrmatch = 0;
 331         if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
 332                 addrmatch |= 1;
 333         if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
 334                 addrmatch |= 2;
 335         if (addrmatch != 3)
 336                 return 0;
 337
 338         /* martian filters on outer source - NOT done in ip_input! */
 339         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
 340                 return 0;
 341         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 342         case 0: case 127: case 255:
 343                 return 0;
 344         }
 345         /* reject packets with broadcast on source */
 346         lck_mtx_lock(rt_mtx);
 347         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 348              ia4 = TAILQ_NEXT(ia4, ia_link))
 349         {
 350                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
 351                         continue;
 352                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 353                         lck_mtx_unlock(rt_mtx);
 354                         return 0;
 355                 }
 356         }
 357         lck_mtx_unlock(rt_mtx);
 358
 359         /* ingress filters on outer source */
 360         if ((sc->gif_if.if_flags & IFF_LINK2) == 0 &&
 361             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 362                 struct sockaddr_in sin;
 363                 struct rtentry *rt;
 364
 365                 bzero(&sin, sizeof(sin));
 366                 sin.sin_family = AF_INET;
 367                 sin.sin_len = sizeof(struct sockaddr_in);
 368                 sin.sin_addr = ip.ip_src;
 369                 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
 370                 if (!rt || rt->rt_ifp != m->m_pkthdr.rcvif) {
 371 #if 0
 372                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
 373                             "due to ingress filter\n", if_name(&sc->gif_if),
 374                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
 375 #endif
 376                         if (rt)
 377                                 rtfree(rt);
 378                         return 0;
 379                 }
 380                 rtfree(rt);
 381         }
 382
 383         return 32 * 2;
 384 }