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