bsd/netinet/in_gif.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 /*      $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 int ip_gif_ttl = GIF_TTL;
  97 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW | CTLFLAG_LOCKED,
  98         &ip_gif_ttl,    0, "");
  99
 100 int
 101 in_gif_output(
 102         struct ifnet    *ifp,
 103         int             family,
 104         struct mbuf     *m,
 105         __unused struct rtentry *rt)
 106 {
 107         struct gif_softc *sc = ifnet_softc(ifp);
 108         struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
 109         struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
 110         struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
 111         struct ip iphdr;        /* capsule IP header, host byte ordered */
 112         int proto, error;
 113         u_int8_t tos;
 114         struct ip_out_args ipoa = { IFSCOPE_NONE, 0 };
 115
 116         if (sin_src == NULL || sin_dst == NULL ||
 117             sin_src->sin_family != AF_INET ||
 118             sin_dst->sin_family != AF_INET) {
 119                 m_freem(m);
 120                 return EAFNOSUPPORT;
 121         }
 122
 123         switch (family) {
 124 #if INET
 125         case AF_INET:
 126             {
 127                 struct ip *ip;
 128
 129                 proto = IPPROTO_IPV4;
 130                 if (mbuf_len(m) < sizeof(*ip)) {
 131                         m = m_pullup(m, sizeof(*ip));
 132                         if (!m)
 133                                 return ENOBUFS;
 134                 }
 135                 ip = mtod(m, struct ip *);
 136                 tos = ip->ip_tos;
 137                 break;
 138             }
 139 #endif /*INET*/
 140 #if INET6
 141         case AF_INET6:
 142             {
 143                 struct ip6_hdr *ip6;
 144                 proto = IPPROTO_IPV6;
 145                 if (mbuf_len(m) < sizeof(*ip6)) {
 146                         m = m_pullup(m, sizeof(*ip6));
 147                         if (!m)
 148                                 return ENOBUFS;
 149                 }
 150                 ip6 = mtod(m, struct ip6_hdr *);
 151                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 152                 break;
 153             }
 154 #endif /*INET6*/
 155         default:
 156 #if DEBUG
 157                 printf("in_gif_output: warning: unknown family %d passed\n",
 158                         family);
 159 #endif
 160                 m_freem(m);
 161                 return EAFNOSUPPORT;
 162         }
 163
 164         bzero(&iphdr, sizeof(iphdr));
 165         iphdr.ip_src = sin_src->sin_addr;
 166         /* bidirectional configured tunnel mode */
 167         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 168                 iphdr.ip_dst = sin_dst->sin_addr;
 169         else {
 170                 m_freem(m);
 171                 return ENETUNREACH;
 172         }
 173         iphdr.ip_p = proto;
 174         /* version will be set in ip_output() */
 175         iphdr.ip_ttl = ip_gif_ttl;
 176         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
 177         if (ifp->if_flags & IFF_LINK1)
 178                 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
 179         else
 180                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 181
 182         /* prepend new IP header */
 183         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 184         if (m && mbuf_len(m) < sizeof(struct ip))
 185                 m = m_pullup(m, sizeof(struct ip));
 186         if (m == NULL) {
 187                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 188                 return ENOBUFS;
 189         }
 190         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 191
 192         if (dst->sin_family != sin_dst->sin_family ||
 193             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
 194             (sc->gif_ro.ro_rt != NULL &&
 195             (sc->gif_ro.ro_rt->generation_id != route_generation ||
 196             sc->gif_ro.ro_rt->rt_ifp == ifp))) {
 197                 /* cache route doesn't match or recursive route */
 198                 dst->sin_family = sin_dst->sin_family;
 199                 dst->sin_len = sizeof(struct sockaddr_in);
 200                 dst->sin_addr = sin_dst->sin_addr;
 201                 if (sc->gif_ro.ro_rt) {
 202                         rtfree(sc->gif_ro.ro_rt);
 203                         sc->gif_ro.ro_rt = NULL;
 204                 }
 205 #if 0
 206                 sc->gif_if.if_mtu = GIF_MTU;
 207 #endif
 208         }
 209
 210         if (sc->gif_ro.ro_rt == NULL) {
 211                 rtalloc(&sc->gif_ro);
 212                 if (sc->gif_ro.ro_rt == NULL) {
 213                         m_freem(m);
 214                         return ENETUNREACH;
 215                 }
 216
 217                 /* if it constitutes infinite encapsulation, punt. */
 218                 RT_LOCK(sc->gif_ro.ro_rt);
 219                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 220                         RT_UNLOCK(sc->gif_ro.ro_rt);
 221                         m_freem(m);
 222                         return ENETUNREACH;     /*XXX*/
 223                 }
 224 #if 0
 225                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 226                         - sizeof(struct ip);
 227 #endif
 228                 RT_UNLOCK(sc->gif_ro.ro_rt);
 229         }
 230
 231         error = ip_output(m, NULL, &sc->gif_ro, IP_OUTARGS, NULL, &ipoa);
 232         return(error);
 233 }
 234
 235 void
 236 in_gif_input(m, off)
 237         struct mbuf *m;
 238         int off;
 239 {
 240         struct ifnet *gifp = NULL;
 241         struct ip *ip;
 242         int af, proto;
 243         u_int8_t otos;
 244
 245         ip = mtod(m, struct ip *);
 246         proto = ip->ip_p;
 247
 248
 249         gifp = ((struct gif_softc*)encap_getarg(m))->gif_if;
 250
 251         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 252                 m_freem(m);
 253                 OSAddAtomic(1, &ipstat.ips_nogif);
 254                 return;
 255         }
 256
 257         otos = ip->ip_tos;
 258         m_adj(m, off);
 259
 260         switch (proto) {
 261 #if INET
 262         case IPPROTO_IPV4:
 263             {
 264                 af = AF_INET;
 265                 if (mbuf_len(m) < sizeof(*ip)) {
 266                         m = m_pullup(m, sizeof(*ip));
 267                         if (!m)
 268                                 return;
 269                 }
 270                 ip = mtod(m, struct ip *);
 271                 if (gifp->if_flags & IFF_LINK1)
 272                         ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
 273                 else
 274                         ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 275                 break;
 276             }
 277 #endif
 278 #if INET6
 279         case IPPROTO_IPV6:
 280             {
 281                 struct ip6_hdr *ip6;
 282                 u_int8_t itos;
 283                 af = AF_INET6;
 284                 if (mbuf_len(m) < sizeof(*ip6)) {
 285                         m = m_pullup(m, sizeof(*ip6));
 286                         if (!m)
 287                                 return;
 288                 }
 289                 ip6 = mtod(m, struct ip6_hdr *);
 290                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 291                 if (gifp->if_flags & IFF_LINK1)
 292                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 293                 else
 294                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 295                 ip6->ip6_flow &= ~htonl(0xff << 20);
 296                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 297                 break;
 298             }
 299 #endif /* INET6 */
 300         default:
 301                 OSAddAtomic(1, &ipstat.ips_nogif);
 302                 m_freem(m);
 303                 return;
 304         }
 305 #ifdef __APPLE__
 306         /* Should we free m if dlil_input returns an error? */
 307         if (m->m_pkthdr.rcvif)  /* replace the rcvif by gifp for dlil to route it correctly */
 308                 m->m_pkthdr.rcvif = gifp;
 309         ifnet_input(gifp, m, NULL);
 310 #else
 311         gif_input(m, af, gifp);
 312 #endif
 313         return;
 314 }
 315
 316 static __inline__ void*
 317 _cast_non_const(const void * ptr) {
 318         union {
 319                 const void*             cval;
 320                 void*                   val;
 321         } ret;
 322
 323         ret.cval = ptr;
 324         return (ret.val);
 325 }
 326
 327 /*
 328  * we know that we are in IFF_UP, outer address available, and outer family
 329  * matched the physical addr family.  see gif_encapcheck().
 330  */
 331 int
 332 gif_encapcheck4(
 333         const struct mbuf *m,
 334         __unused int off,
 335         __unused int proto,
 336         void *arg)
 337 {
 338         struct ip ip;
 339         struct gif_softc *sc;
 340         struct sockaddr_in *src, *dst;
 341         int addrmatch;
 342         struct in_ifaddr *ia4;
 343
 344         /* sanity check done in caller */
 345         sc = (struct gif_softc *)arg;
 346         src = (struct sockaddr_in *)sc->gif_psrc;
 347         dst = (struct sockaddr_in *)sc->gif_pdst;
 348
 349         mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof(ip), &ip);
 350
 351         /* check for address match */
 352         addrmatch = 0;
 353         if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
 354                 addrmatch |= 1;
 355         if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
 356                 addrmatch |= 2;
 357         if (addrmatch != 3)
 358                 return 0;
 359
 360         /* martian filters on outer source - NOT done in ip_input! */
 361         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
 362                 return 0;
 363         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 364         case 0: case 127: case 255:
 365                 return 0;
 366         }
 367         /* reject packets with broadcast on source */
 368         lck_rw_lock_shared(in_ifaddr_rwlock);
 369         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 370              ia4 = TAILQ_NEXT(ia4, ia_link))
 371         {
 372                 if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0)
 373                         continue;
 374                 IFA_LOCK(&ia4->ia_ifa);
 375                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 376                         IFA_UNLOCK(&ia4->ia_ifa);
 377                         lck_rw_done(in_ifaddr_rwlock);
 378                         return 0;
 379                 }
 380                 IFA_UNLOCK(&ia4->ia_ifa);
 381         }
 382         lck_rw_done(in_ifaddr_rwlock);
 383
 384         /* ingress filters on outer source */
 385         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
 386             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 387                 struct sockaddr_in sin;
 388                 struct rtentry *rt;
 389
 390                 bzero(&sin, sizeof(sin));
 391                 sin.sin_family = AF_INET;
 392                 sin.sin_len = sizeof(struct sockaddr_in);
 393                 sin.sin_addr = ip.ip_src;
 394                 rt = rtalloc1_scoped((struct sockaddr *)&sin, 0, 0,
 395                     m->m_pkthdr.rcvif->if_index);
 396                 if (rt != NULL)
 397                         RT_LOCK(rt);
 398                 if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
 399                         if (rt != NULL) {
 400                                 RT_UNLOCK(rt);
 401                                 rtfree(rt);
 402                         }
 403                         return 0;
 404                 }
 405                 RT_UNLOCK(rt);
 406                 rtfree(rt);
 407         }
 408
 409         return 32 * 2;
 410 }