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 int ip_gif_ttl = GIF_TTL;
  97 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
  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
 115         if (sin_src == NULL || sin_dst == NULL ||
 116             sin_src->sin_family != AF_INET ||
 117             sin_dst->sin_family != AF_INET) {
 118                 m_freem(m);
 119                 return EAFNOSUPPORT;
 120         }
 121
 122         switch (family) {
 123 #if INET
 124         case AF_INET:
 125             {
 126                 struct ip *ip;
 127
 128                 proto = IPPROTO_IPV4;
 129                 if (mbuf_len(m) < sizeof(*ip)) {
 130                         m = m_pullup(m, sizeof(*ip));
 131                         if (!m)
 132                                 return ENOBUFS;
 133                 }
 134                 ip = mtod(m, struct ip *);
 135                 tos = ip->ip_tos;
 136                 break;
 137             }
 138 #endif /*INET*/
 139 #if INET6
 140         case AF_INET6:
 141             {
 142                 struct ip6_hdr *ip6;
 143                 proto = IPPROTO_IPV6;
 144                 if (mbuf_len(m) < sizeof(*ip6)) {
 145                         m = m_pullup(m, sizeof(*ip6));
 146                         if (!m)
 147                                 return ENOBUFS;
 148                 }
 149                 ip6 = mtod(m, struct ip6_hdr *);
 150                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 151                 break;
 152             }
 153 #endif /*INET6*/
 154         default:
 155 #if DEBUG
 156                 printf("in_gif_output: warning: unknown family %d passed\n",
 157                         family);
 158 #endif
 159                 m_freem(m);
 160                 return EAFNOSUPPORT;
 161         }
 162
 163         bzero(&iphdr, sizeof(iphdr));
 164         iphdr.ip_src = sin_src->sin_addr;
 165         /* bidirectional configured tunnel mode */
 166         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 167                 iphdr.ip_dst = sin_dst->sin_addr;
 168         else {
 169                 m_freem(m);
 170                 return ENETUNREACH;
 171         }
 172         iphdr.ip_p = proto;
 173         /* version will be set in ip_output() */
 174         iphdr.ip_ttl = ip_gif_ttl;
 175         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
 176         if (ifp->if_flags & IFF_LINK1)
 177                 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
 178         else
 179                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 180
 181         /* prepend new IP header */
 182         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 183         if (m && mbuf_len(m) < sizeof(struct ip))
 184                 m = m_pullup(m, sizeof(struct ip));
 185         if (m == NULL) {
 186                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 187                 return ENOBUFS;
 188         }
 189         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 190
 191         if (dst->sin_family != sin_dst->sin_family ||
 192             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
 193                 /* cache route doesn't match */
 194                 dst->sin_family = sin_dst->sin_family;
 195                 dst->sin_len = sizeof(struct sockaddr_in);
 196                 dst->sin_addr = sin_dst->sin_addr;
 197                 if (sc->gif_ro.ro_rt) {
 198                         rtfree(sc->gif_ro.ro_rt);
 199                         sc->gif_ro.ro_rt = NULL;
 200                 }
 201 #if 0
 202                 sc->gif_if.if_mtu = GIF_MTU;
 203 #endif
 204         }
 205
 206         if (sc->gif_ro.ro_rt == NULL) {
 207                 rtalloc(&sc->gif_ro);
 208                 if (sc->gif_ro.ro_rt == NULL) {
 209                         m_freem(m);
 210                         return ENETUNREACH;
 211                 }
 212
 213                 /* if it constitutes infinite encapsulation, punt. */
 214                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 215                         m_freem(m);
 216                         return ENETUNREACH;     /*XXX*/
 217                 }
 218 #if 0
 219                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 220                         - sizeof(struct ip);
 221 #endif
 222         }
 223
 224         error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
 225         return(error);
 226 }
 227
 228 void
 229 in_gif_input(m, off)
 230         struct mbuf *m;
 231         int off;
 232 {
 233         struct ifnet *gifp = NULL;
 234         struct ip *ip;
 235         int af, proto;
 236         u_int8_t otos;
 237
 238         ip = mtod(m, struct ip *);
 239         proto = ip->ip_p;
 240
 241
 242         gifp = ((struct gif_softc*)encap_getarg(m))->gif_if;
 243
 244         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 245                 m_freem(m);
 246                 OSAddAtomic(1, (SInt32*)&ipstat.ips_nogif);
 247                 return;
 248         }
 249
 250         otos = ip->ip_tos;
 251         m_adj(m, off);
 252
 253         switch (proto) {
 254 #if INET
 255         case IPPROTO_IPV4:
 256             {
 257                 af = AF_INET;
 258                 if (mbuf_len(m) < sizeof(*ip)) {
 259                         m = m_pullup(m, sizeof(*ip));
 260                         if (!m)
 261                                 return;
 262                 }
 263                 ip = mtod(m, struct ip *);
 264                 if (gifp->if_flags & IFF_LINK1)
 265                         ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
 266                 else
 267                         ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 268                 break;
 269             }
 270 #endif
 271 #if INET6
 272         case IPPROTO_IPV6:
 273             {
 274                 struct ip6_hdr *ip6;
 275                 u_int8_t itos;
 276                 af = AF_INET6;
 277                 if (mbuf_len(m) < sizeof(*ip6)) {
 278                         m = m_pullup(m, sizeof(*ip6));
 279                         if (!m)
 280                                 return;
 281                 }
 282                 ip6 = mtod(m, struct ip6_hdr *);
 283                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 284                 if (gifp->if_flags & IFF_LINK1)
 285                         ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 286                 else
 287                         ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 288                 ip6->ip6_flow &= ~htonl(0xff << 20);
 289                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 290                 break;
 291             }
 292 #endif /* INET6 */
 293         default:
 294                 OSAddAtomic(1, (SInt32*)&ipstat.ips_nogif);
 295                 m_freem(m);
 296                 return;
 297         }
 298 #ifdef __APPLE__
 299         /* Should we free m if dlil_input returns an error? */
 300         if (m->m_pkthdr.rcvif)  /* replace the rcvif by gifp for dlil to route it correctly */
 301                 m->m_pkthdr.rcvif = gifp;
 302         ifnet_input(gifp, m, NULL);
 303 #else
 304         gif_input(m, af, gifp);
 305 #endif
 306         return;
 307 }
 308
 309 static __inline__ void*
 310 _cast_non_const(const void * ptr) {
 311         union {
 312                 const void*             cval;
 313                 void*                   val;
 314         } ret;
 315
 316         ret.cval = ptr;
 317         return (ret.val);
 318 }
 319
 320 /*
 321  * we know that we are in IFF_UP, outer address available, and outer family
 322  * matched the physical addr family.  see gif_encapcheck().
 323  */
 324 int
 325 gif_encapcheck4(
 326         const struct mbuf *m,
 327         __unused int off,
 328         __unused int proto,
 329         void *arg)
 330 {
 331         struct ip ip;
 332         struct gif_softc *sc;
 333         struct sockaddr_in *src, *dst;
 334         int addrmatch;
 335         struct in_ifaddr *ia4;
 336
 337         /* sanity check done in caller */
 338         sc = (struct gif_softc *)arg;
 339         src = (struct sockaddr_in *)sc->gif_psrc;
 340         dst = (struct sockaddr_in *)sc->gif_pdst;
 341
 342         mbuf_copydata(m, 0, sizeof(ip), &ip);
 343
 344         /* check for address match */
 345         addrmatch = 0;
 346         if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
 347                 addrmatch |= 1;
 348         if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
 349                 addrmatch |= 2;
 350         if (addrmatch != 3)
 351                 return 0;
 352
 353         /* martian filters on outer source - NOT done in ip_input! */
 354         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
 355                 return 0;
 356         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 357         case 0: case 127: case 255:
 358                 return 0;
 359         }
 360         /* reject packets with broadcast on source */
 361         lck_mtx_lock(rt_mtx);
 362         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 363              ia4 = TAILQ_NEXT(ia4, ia_link))
 364         {
 365                 if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0)
 366                         continue;
 367                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 368                         lck_mtx_unlock(rt_mtx);
 369                         return 0;
 370                 }
 371         }
 372         lck_mtx_unlock(rt_mtx);
 373
 374         /* ingress filters on outer source */
 375         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
 376             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 377                 struct sockaddr_in sin;
 378                 struct rtentry *rt;
 379
 380                 bzero(&sin, sizeof(sin));
 381                 sin.sin_family = AF_INET;
 382                 sin.sin_len = sizeof(struct sockaddr_in);
 383                 sin.sin_addr = ip.ip_src;
 384                 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
 385                 if (!rt || rt->rt_ifp != m->m_pkthdr.rcvif) {
 386 #if 0
 387                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
 388                             "due to ingress filter\n", if_name(&sc->gif_if),
 389                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
 390 #endif
 391                         if (rt)
 392                                 rtfree(rt);
 393                         return 0;
 394                 }
 395                 rtfree(rt);
 396         }
 397
 398         return 32 * 2;
 399 }