bsd/netinet/in_gif.c

   1 /*
   2  * Copyright (c) 2000-2013 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 #include <net/if_gif.h>
  89
  90 #include <net/net_osdep.h>
  91
  92 int ip_gif_ttl = GIF_TTL;
  93 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW | CTLFLAG_LOCKED,
  94         &ip_gif_ttl,    0, "");
  95
  96 int
  97 in_gif_output(
  98         struct ifnet    *ifp,
  99         int             family,
 100         struct mbuf     *m,
 101         __unused struct rtentry *rt)
 102 {
 103         struct gif_softc *sc = ifnet_softc(ifp);
 104         struct sockaddr_in *dst = (struct sockaddr_in *)
 105             (void *)&sc->gif_ro.ro_dst;
 106         struct sockaddr_in *sin_src = (struct sockaddr_in *)
 107             (void *)sc->gif_psrc;
 108         struct sockaddr_in *sin_dst = (struct sockaddr_in *)
 109             (void *)sc->gif_pdst;
 110         struct ip iphdr;        /* capsule IP header, host byte ordered */
 111         int proto, error;
 112         u_int8_t tos;
 113         struct ip_out_args ipoa =
 114             { IFSCOPE_NONE, { 0 }, IPOAF_SELECT_SRCIF, 0 };
 115
 116         GIF_LOCK_ASSERT(sc);
 117
 118         if (sin_src == NULL || sin_dst == NULL ||
 119             sin_src->sin_family != AF_INET ||
 120             sin_dst->sin_family != AF_INET) {
 121                 m_freem(m);
 122                 return (EAFNOSUPPORT);
 123         }
 124
 125         switch (family) {
 126 #if INET
 127         case AF_INET:
 128             {
 129                 struct ip *ip;
 130
 131                 proto = IPPROTO_IPV4;
 132                 if (mbuf_len(m) < sizeof (*ip)) {
 133                         m = m_pullup(m, sizeof (*ip));
 134                         if (!m)
 135                                 return (ENOBUFS);
 136                 }
 137                 ip = mtod(m, struct ip *);
 138                 tos = ip->ip_tos;
 139                 break;
 140             }
 141 #endif /* INET */
 142 #if INET6
 143         case AF_INET6:
 144             {
 145                 struct ip6_hdr *ip6;
 146                 proto = IPPROTO_IPV6;
 147                 if (mbuf_len(m) < sizeof (*ip6)) {
 148                         m = m_pullup(m, sizeof (*ip6));
 149                         if (!m)
 150                                 return (ENOBUFS);
 151                 }
 152                 ip6 = mtod(m, struct ip6_hdr *);
 153                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 154                 break;
 155             }
 156 #endif /* INET6 */
 157         default:
 158 #if DEBUG
 159                 printf("in_gif_output: warning: unknown family %d passed\n",
 160                         family);
 161 #endif
 162                 m_freem(m);
 163                 return (EAFNOSUPPORT);
 164         }
 165
 166         bzero(&iphdr, sizeof (iphdr));
 167         iphdr.ip_src = sin_src->sin_addr;
 168         /* bidirectional configured tunnel mode */
 169         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 170                 iphdr.ip_dst = sin_dst->sin_addr;
 171         else {
 172                 m_freem(m);
 173                 return (ENETUNREACH);
 174         }
 175         iphdr.ip_p = proto;
 176         /* version will be set in ip_output() */
 177         iphdr.ip_ttl = ip_gif_ttl;
 178         iphdr.ip_len = m->m_pkthdr.len + sizeof (struct ip);
 179         if (ifp->if_flags & IFF_LINK1)
 180                 ip_ecn_ingress(ECN_NORMAL, &iphdr.ip_tos, &tos);
 181         else
 182                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 183
 184         /* prepend new IP header */
 185         M_PREPEND(m, sizeof (struct ip), M_DONTWAIT, 0);
 186         if (m && mbuf_len(m) < sizeof (struct ip))
 187                 m = m_pullup(m, sizeof (struct ip));
 188         if (m == NULL) {
 189                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 190                 return (ENOBUFS);
 191         }
 192         bcopy(&iphdr, mtod(m, struct ip *), sizeof (struct ip));
 193
 194         if (ROUTE_UNUSABLE(&sc->gif_ro) ||
 195             dst->sin_family != sin_dst->sin_family ||
 196             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
 197             (sc->gif_ro.ro_rt != NULL && sc->gif_ro.ro_rt->rt_ifp == ifp)) {
 198                 /* cache route doesn't match or recursive route */
 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                 ROUTE_RELEASE(&sc->gif_ro);
 203 #if 0
 204                 sc->gif_if.if_mtu = GIF_MTU;
 205 #endif
 206         }
 207
 208         if (sc->gif_ro.ro_rt == NULL) {
 209                 rtalloc(&sc->gif_ro);
 210                 if (sc->gif_ro.ro_rt == NULL) {
 211                         m_freem(m);
 212                         return (ENETUNREACH);
 213                 }
 214
 215                 /* if it constitutes infinite encapsulation, punt. */
 216                 RT_LOCK(sc->gif_ro.ro_rt);
 217                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 218                         RT_UNLOCK(sc->gif_ro.ro_rt);
 219                         m_freem(m);
 220                         return (ENETUNREACH); /* XXX */
 221                 }
 222 #if 0
 223                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 224                     - sizeof (struct ip);
 225 #endif
 226                 RT_UNLOCK(sc->gif_ro.ro_rt);
 227         }
 228
 229         error = ip_output(m, NULL, &sc->gif_ro, IP_OUTARGS, NULL, &ipoa);
 230
 231         return (error);
 232 }
 233
 234 void
 235 in_gif_input(m, off)
 236         struct mbuf *m;
 237         int off;
 238 {
 239         struct ifnet *gifp = NULL;
 240         struct ip *ip;
 241         int af, proto;
 242         u_int8_t otos, old_tos;
 243         int egress_success = 0;
 244         int sum;
 245
 246         ip = mtod(m, struct ip *);
 247         proto = ip->ip_p;
 248
 249
 250         gifp = ((struct gif_softc *)encap_getarg(m))->gif_if;
 251
 252         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 253                 m_freem(m);
 254                 OSAddAtomic(1, &ipstat.ips_nogif);
 255                 return;
 256         }
 257
 258         otos = ip->ip_tos;
 259         m_adj(m, off);
 260
 261         switch (proto) {
 262 #if INET
 263         case IPPROTO_IPV4:
 264             {
 265                 af = AF_INET;
 266                 if (mbuf_len(m) < sizeof (*ip)) {
 267                         m = m_pullup(m, sizeof (*ip));
 268                         if (!m)
 269                                 return;
 270                 }
 271                 ip = mtod(m, struct ip *);
 272                 if (gifp->if_flags & IFF_LINK1) {
 273                         old_tos = ip->ip_tos;
 274                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &ip->ip_tos);
 275                         if (old_tos != ip->ip_tos) {
 276                             sum = ~ntohs(ip->ip_sum) & 0xffff;
 277                             sum += (~otos & 0xffff) + ip->ip_tos;
 278                             sum = (sum >> 16) + (sum & 0xffff);
 279                             sum += (sum >> 16);  /* add carry */
 280                             ip->ip_sum = htons(~sum & 0xffff);
 281                         }
 282                 } else
 283                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 284                 break;
 285             }
 286 #endif
 287 #if INET6
 288         case IPPROTO_IPV6:
 289             {
 290                 struct ip6_hdr *ip6;
 291                 u_int8_t itos;
 292                 af = AF_INET6;
 293                 if (mbuf_len(m) < sizeof (*ip6)) {
 294                         m = m_pullup(m, sizeof (*ip6));
 295                         if (!m)
 296                                 return;
 297                 }
 298                 ip6 = mtod(m, struct ip6_hdr *);
 299                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 300                 if (gifp->if_flags & IFF_LINK1)
 301                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &itos);
 302                 else
 303                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 304                 ip6->ip6_flow &= ~htonl(0xff << 20);
 305                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 306                 break;
 307             }
 308 #endif /* INET6 */
 309         default:
 310                 OSAddAtomic(1, &ipstat.ips_nogif);
 311                 m_freem(m);
 312                 return;
 313         }
 314
 315         if (egress_success == 0) {
 316                 OSAddAtomic(1, &ipstat.ips_nogif);
 317                 m_freem(m);
 318                 return;
 319         }
 320
 321 #ifdef __APPLE__
 322         /* Replace the rcvif by gifp for dlil to route it correctly */
 323         if (m->m_pkthdr.rcvif)
 324                 m->m_pkthdr.rcvif = gifp;
 325         ifnet_input(gifp, m, NULL);
 326 #else
 327         gif_input(m, af, gifp);
 328 #endif
 329 }
 330
 331 /*
 332  * We know that we are in IFF_UP, outer address available, and outer family
 333  * matched the physical addr family.  see gif_encapcheck().
 334  */
 335 int
 336 gif_encapcheck4(
 337         const struct mbuf *m,
 338         __unused int off,
 339         __unused int proto,
 340         void *arg)
 341 {
 342         struct ip ip;
 343         struct gif_softc *sc;
 344         struct sockaddr_in *src, *dst;
 345         int addrmatch;
 346         struct in_ifaddr *ia4;
 347
 348         /* sanity check done in caller */
 349         sc = (struct gif_softc *)arg;
 350         src = (struct sockaddr_in *)(void *)sc->gif_psrc;
 351         dst = (struct sockaddr_in *)(void *)sc->gif_pdst;
 352
 353         GIF_LOCK_ASSERT(sc);
 354
 355         mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof (ip), &ip);
 356
 357         /* check for address match */
 358         addrmatch = 0;
 359         if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
 360                 addrmatch |= 1;
 361         if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
 362                 addrmatch |= 2;
 363         if (addrmatch != 3)
 364                 return (0);
 365
 366         /* martian filters on outer source - NOT done in ip_input! */
 367         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
 368                 return (0);
 369         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 370         case 0: case 127: case 255:
 371                 return (0);
 372         }
 373         /* reject packets with broadcast on source */
 374         lck_rw_lock_shared(in_ifaddr_rwlock);
 375         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 376             ia4 = TAILQ_NEXT(ia4, ia_link)) {
 377                 if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0)
 378                         continue;
 379                 IFA_LOCK(&ia4->ia_ifa);
 380                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 381                         IFA_UNLOCK(&ia4->ia_ifa);
 382                         lck_rw_done(in_ifaddr_rwlock);
 383                         return (0);
 384                 }
 385                 IFA_UNLOCK(&ia4->ia_ifa);
 386         }
 387         lck_rw_done(in_ifaddr_rwlock);
 388
 389         /* ingress filters on outer source */
 390         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
 391             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 392                 struct sockaddr_in sin;
 393                 struct rtentry *rt;
 394
 395                 bzero(&sin, sizeof (sin));
 396                 sin.sin_family = AF_INET;
 397                 sin.sin_len = sizeof (struct sockaddr_in);
 398                 sin.sin_addr = ip.ip_src;
 399                 rt = rtalloc1_scoped((struct sockaddr *)&sin, 0, 0,
 400                     m->m_pkthdr.rcvif->if_index);
 401                 if (rt != NULL)
 402                         RT_LOCK(rt);
 403                 if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
 404                         if (rt != NULL) {
 405                                 RT_UNLOCK(rt);
 406                                 rtfree(rt);
 407                         }
 408                         return (0);
 409                 }
 410                 RT_UNLOCK(rt);
 411                 rtfree(rt);
 412         }
 413
 414         return (32 * 2);
 415 }