bsd/netinet/in_gif.c

   1 /*
   2  * Copyright (c) 2000-2007 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 /*      $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ */
  29
  30 /*
  31  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  32  * All rights reserved.
  33  *
  34  * Redistribution and use in source and binary forms, with or without
  35  * modification, are permitted provided that the following conditions
  36  * are met:
  37  * 1. Redistributions of source code must retain the above copyright
  38  *    notice, this list of conditions and the following disclaimer.
  39  * 2. Redistributions in binary form must reproduce the above copyright
  40  *    notice, this list of conditions and the following disclaimer in the
  41  *    documentation and/or other materials provided with the distribution.
  42  * 3. Neither the name of the project nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  */
  58
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/socket.h>
  63 #include <sys/sockio.h>
  64 #include <sys/mbuf.h>
  65 #include <sys/errno.h>
  66 #include <sys/kernel.h>
  67 #include <sys/sysctl.h>
  68
  69 #include <sys/malloc.h>
  70 #include <libkern/OSAtomic.h>
  71
  72 #include <net/if.h>
  73 #include <net/route.h>
  74
  75 #include <netinet/in.h>
  76 #include <netinet/in_systm.h>
  77 #include <netinet/ip.h>
  78 #include <netinet/ip_var.h>
  79 #include <netinet/in_gif.h>
  80 #include <netinet/in_var.h>
  81 #include <netinet/ip_encap.h>
  82 #include <netinet/ip_ecn.h>
  83
  84 #if INET6
  85 #include <netinet/ip6.h>
  86 #endif
  87
  88 #if MROUTING
  89 #include <netinet/ip_mroute.h>
  90 #endif /* MROUTING */
  91
  92 #include <net/if_gif.h>
  93
  94 #include <net/net_osdep.h>
  95
  96 extern u_long  route_generation;
  97
  98 int ip_gif_ttl = GIF_TTL;
  99 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
 100         &ip_gif_ttl,    0, "");
 101
 102 int
 103 in_gif_output(
 104         struct ifnet    *ifp,
 105         int             family,
 106         struct mbuf     *m,
 107         __unused struct rtentry *rt)
 108 {
 109         struct gif_softc *sc = ifnet_softc(ifp);
 110         struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
 111         struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
 112         struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
 113         struct ip iphdr;        /* capsule IP header, host byte ordered */
 114         int proto, error;
 115         u_int8_t tos;
 116
 117         if (sin_src == NULL || sin_dst == NULL ||
 118             sin_src->sin_family != AF_INET ||
 119             sin_dst->sin_family != AF_INET) {
 120                 m_freem(m);
 121                 return EAFNOSUPPORT;
 122         }
 123
 124         switch (family) {
 125 #if INET
 126         case AF_INET:
 127             {
 128                 struct ip *ip;
 129
 130                 proto = IPPROTO_IPV4;
 131                 if (mbuf_len(m) < sizeof(*ip)) {
 132                         m = m_pullup(m, sizeof(*ip));
 133                         if (!m)
 134                                 return ENOBUFS;
 135                 }
 136                 ip = mtod(m, struct ip *);
 137                 tos = ip->ip_tos;
 138                 break;
 139             }
 140 #endif /*INET*/
 141 #if INET6
 142         case AF_INET6:
 143             {
 144                 struct ip6_hdr *ip6;
 145                 proto = IPPROTO_IPV6;
 146                 if (mbuf_len(m) < sizeof(*ip6)) {
 147                         m = m_pullup(m, sizeof(*ip6));
 148                         if (!m)
 149                                 return ENOBUFS;
 150                 }
 151                 ip6 = mtod(m, struct ip6_hdr *);
 152                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 153                 break;
 154             }
 155 #endif /*INET6*/
 156         default:
 157 #if DEBUG
 158                 printf("in_gif_output: warning: unknown family %d passed\n",
 159                         family);
 160 #endif
 161                 m_freem(m);
 162                 return EAFNOSUPPORT;
 163         }
 164
 165         bzero(&iphdr, sizeof(iphdr));
 166         iphdr.ip_src = sin_src->sin_addr;
 167         /* bidirectional configured tunnel mode */
 168         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 169                 iphdr.ip_dst = sin_dst->sin_addr;
 170         else {
 171                 m_freem(m);
 172                 return ENETUNREACH;
 173         }
 174         iphdr.ip_p = proto;
 175         /* version will be set in ip_output() */
 176         iphdr.ip_ttl = ip_gif_ttl;
 177         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
 178         if (ifp->if_flags & IFF_LINK1)
 179                 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
 180         else
 181                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 182
 183         /* prepend new IP header */
 184         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 185         if (m && mbuf_len(m) < sizeof(struct ip))
 186                 m = m_pullup(m, sizeof(struct ip));
 187         if (m == NULL) {
 188                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 189                 return ENOBUFS;
 190         }
 191         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 192
 193         if (dst->sin_family != sin_dst->sin_family ||
 194             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
 195             (sc->gif_ro.ro_rt != NULL &&
 196             (sc->gif_ro.ro_rt->generation_id != route_generation ||
 197             sc->gif_ro.ro_rt->rt_ifp == ifp))) {
 198                 /* cache route doesn't match */
 199                 dst->sin_family = sin_dst->sin_family;
 200                 dst->sin_len = sizeof(struct sockaddr_in);
 201                 dst->sin_addr = sin_dst->sin_addr;
 202                 if (sc->gif_ro.ro_rt) {
 203                         rtfree(sc->gif_ro.ro_rt);
 204                         sc->gif_ro.ro_rt = NULL;
 205                 }
 206 #if 0
 207                 sc->gif_if.if_mtu = GIF_MTU;
 208 #endif
 209         }
 210
 211         if (sc->gif_ro.ro_rt == NULL) {
 212                 rtalloc(&sc->gif_ro);
 213                 if (sc->gif_ro.ro_rt == NULL) {
 214                         m_freem(m);
 215                         return ENETUNREACH;
 216                 }
 217
 218                 /* if it constitutes infinite encapsulation, punt. */
 219                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 220                         m_freem(m);
 221                         return ENETUNREACH;     /*XXX*/
 222                 }
 223 #if 0
 224                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 225                         - sizeof(struct ip);
 226 #endif
 227         }
 228
 229         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
 230         return(error);
 231 }
 232
 233 void
 234 in_gif_input(m, off)
 235         struct mbuf *m;
 236         int off;
 237 {
 238         struct ifnet *gifp = NULL;
 239         struct ip *ip;
 240         int af, proto;
 241         u_int8_t otos;
 242
 243         ip = mtod(m, struct ip *);
 244         proto = ip->ip_p;
 245
 246
 247         gifp = ((struct gif_softc*)encap_getarg(m))->gif_if;
 248
 249         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 250                 m_freem(m);
 251                 OSAddAtomic(1, (SInt32*)&ipstat.ips_nogif);
 252                 return;
 253         }
 254
 255         otos = ip->ip_tos;
 256         m_adj(m, off);
 257
 258         switch (proto) {
 259 #if INET
 260         case IPPROTO_IPV4:
 261             {
 262                 af = AF_INET;
 263                 if (mbuf_len(m) < sizeof(*ip)) {
 264                         m = m_pullup(m, sizeof(*ip));
 265                         if (!m)
 266                                 return;
 267                 }
 268                 ip = mtod(m, struct ip *);
 269                 if (gifp->if_flags & IFF_LINK1)
 270                         ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
 271                 else
 272                         ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 273                 break;
 274             }
 275 #endif
 276 #if INET6
 277         case IPPROTO_IPV6:
 278             {
 279                 struct ip6_hdr *ip6;
 280                 u_int8_t itos;
 281                 af = AF_INET6;
 282                 if (mbuf_len(m) < sizeof(*ip6)) {
 283                         m = m_pullup(m, sizeof(*ip6));
 284                         if (!m)
 285                                 return;
 286                 }
 287                 ip6 = mtod(m, struct ip6_hdr *);
 288                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 289                 if (gifp->if_flags & IFF_LINK1)
 290                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 291                 else
 292                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 293                 ip6->ip6_flow &= ~htonl(0xff << 20);
 294                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 295                 break;
 296             }
 297 #endif /* INET6 */
 298         default:
 299                 OSAddAtomic(1, (SInt32*)&ipstat.ips_nogif);
 300                 m_freem(m);
 301                 return;
 302         }
 303 #ifdef __APPLE__
 304         /* Should we free m if dlil_input returns an error? */
 305         if (m->m_pkthdr.rcvif)  /* replace the rcvif by gifp for dlil to route it correctly */
 306                 m->m_pkthdr.rcvif = gifp;
 307         ifnet_input(gifp, m, NULL);
 308 #else
 309         gif_input(m, af, gifp);
 310 #endif
 311         return;
 312 }
 313
 314 static __inline__ void*
 315 _cast_non_const(const void * ptr) {
 316         union {
 317                 const void*             cval;
 318                 void*                   val;
 319         } ret;
 320
 321         ret.cval = ptr;
 322         return (ret.val);
 323 }
 324
 325 /*
 326  * we know that we are in IFF_UP, outer address available, and outer family
 327  * matched the physical addr family.  see gif_encapcheck().
 328  */
 329 int
 330 gif_encapcheck4(
 331         const struct mbuf *m,
 332         __unused int off,
 333         __unused int proto,
 334         void *arg)
 335 {
 336         struct ip ip;
 337         struct gif_softc *sc;
 338         struct sockaddr_in *src, *dst;
 339         int addrmatch;
 340         struct in_ifaddr *ia4;
 341
 342         /* sanity check done in caller */
 343         sc = (struct gif_softc *)arg;
 344         src = (struct sockaddr_in *)sc->gif_psrc;
 345         dst = (struct sockaddr_in *)sc->gif_pdst;
 346
 347         mbuf_copydata(m, 0, sizeof(ip), &ip);
 348
 349         /* check for address match */
 350         addrmatch = 0;
 351         if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
 352                 addrmatch |= 1;
 353         if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
 354                 addrmatch |= 2;
 355         if (addrmatch != 3)
 356                 return 0;
 357
 358         /* martian filters on outer source - NOT done in ip_input! */
 359         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
 360                 return 0;
 361         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 362         case 0: case 127: case 255:
 363                 return 0;
 364         }
 365         /* reject packets with broadcast on source */
 366         lck_mtx_lock(rt_mtx);
 367         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 368              ia4 = TAILQ_NEXT(ia4, ia_link))
 369         {
 370                 if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0)
 371                         continue;
 372                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 373                         lck_mtx_unlock(rt_mtx);
 374                         return 0;
 375                 }
 376         }
 377         lck_mtx_unlock(rt_mtx);
 378
 379         /* ingress filters on outer source */
 380         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
 381             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 382                 struct sockaddr_in sin;
 383                 struct rtentry *rt;
 384
 385                 bzero(&sin, sizeof(sin));
 386                 sin.sin_family = AF_INET;
 387                 sin.sin_len = sizeof(struct sockaddr_in);
 388                 sin.sin_addr = ip.ip_src;
 389                 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
 390                 if (!rt || rt->rt_ifp != m->m_pkthdr.rcvif) {
 391 #if 0
 392                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
 393                             "due to ingress filter\n", if_name(&sc->gif_if),
 394                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
 395 #endif
 396                         if (rt)
 397                                 rtfree(rt);
 398                         return 0;
 399                 }
 400                 rtfree(rt);
 401         }
 402
 403         return 32 * 2;
 404 }