bsd/netinet/in_gif.c

   1 /*
   2  * Copyright (c) 2000-2016 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, SO_TC_UNSPEC,
 115             _NET_SERVICE_TYPE_UNSPEC };
 116
 117         GIF_LOCK_ASSERT(sc);
 118
 119         if (sin_src == NULL || sin_dst == NULL ||
 120             sin_src->sin_family != AF_INET ||
 121             sin_dst->sin_family != AF_INET) {
 122                 m_freem(m);
 123                 return (EAFNOSUPPORT);
 124         }
 125
 126         switch (family) {
 127 #if INET
 128         case AF_INET:
 129             {
 130                 struct ip *ip;
 131
 132                 proto = IPPROTO_IPV4;
 133                 if (mbuf_len(m) < sizeof (*ip)) {
 134                         m = m_pullup(m, sizeof (*ip));
 135                         if (!m)
 136                                 return (ENOBUFS);
 137                 }
 138                 ip = mtod(m, struct ip *);
 139                 tos = ip->ip_tos;
 140                 break;
 141             }
 142 #endif /* INET */
 143 #if INET6
 144         case AF_INET6:
 145             {
 146                 struct ip6_hdr *ip6;
 147                 proto = IPPROTO_IPV6;
 148                 if (mbuf_len(m) < sizeof (*ip6)) {
 149                         m = m_pullup(m, sizeof (*ip6));
 150                         if (!m)
 151                                 return (ENOBUFS);
 152                 }
 153                 ip6 = mtod(m, struct ip6_hdr *);
 154                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 155                 break;
 156             }
 157 #endif /* INET6 */
 158         default:
 159 #if DEBUG
 160                 printf("in_gif_output: warning: unknown family %d passed\n",
 161                         family);
 162 #endif
 163                 m_freem(m);
 164                 return (EAFNOSUPPORT);
 165         }
 166
 167         bzero(&iphdr, sizeof (iphdr));
 168         iphdr.ip_src = sin_src->sin_addr;
 169         /* bidirectional configured tunnel mode */
 170         if (sin_dst->sin_addr.s_addr != INADDR_ANY)
 171                 iphdr.ip_dst = sin_dst->sin_addr;
 172         else {
 173                 m_freem(m);
 174                 return (ENETUNREACH);
 175         }
 176         iphdr.ip_p = proto;
 177         /* version will be set in ip_output() */
 178         iphdr.ip_ttl = ip_gif_ttl;
 179         iphdr.ip_len = m->m_pkthdr.len + sizeof (struct ip);
 180         if (ifp->if_flags & IFF_LINK1)
 181                 ip_ecn_ingress(ECN_NORMAL, &iphdr.ip_tos, &tos);
 182         else
 183                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 184
 185         /* prepend new IP header */
 186         M_PREPEND(m, sizeof (struct ip), M_DONTWAIT, 0);
 187         if (m && mbuf_len(m) < sizeof (struct ip))
 188                 m = m_pullup(m, sizeof (struct ip));
 189         if (m == NULL) {
 190                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 191                 return (ENOBUFS);
 192         }
 193         bcopy(&iphdr, mtod(m, struct ip *), sizeof (struct ip));
 194
 195         if (ROUTE_UNUSABLE(&sc->gif_ro) ||
 196             dst->sin_family != sin_dst->sin_family ||
 197             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
 198             (sc->gif_ro.ro_rt != NULL && sc->gif_ro.ro_rt->rt_ifp == ifp)) {
 199                 /* cache route doesn't match or recursive route */
 200                 dst->sin_family = sin_dst->sin_family;
 201                 dst->sin_len = sizeof (struct sockaddr_in);
 202                 dst->sin_addr = sin_dst->sin_addr;
 203                 ROUTE_RELEASE(&sc->gif_ro);
 204 #if 0
 205                 sc->gif_if.if_mtu = GIF_MTU;
 206 #endif
 207         }
 208
 209         if (sc->gif_ro.ro_rt == NULL) {
 210                 rtalloc(&sc->gif_ro);
 211                 if (sc->gif_ro.ro_rt == NULL) {
 212                         m_freem(m);
 213                         return (ENETUNREACH);
 214                 }
 215
 216                 /* if it constitutes infinite encapsulation, punt. */
 217                 RT_LOCK(sc->gif_ro.ro_rt);
 218                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 219                         RT_UNLOCK(sc->gif_ro.ro_rt);
 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                 RT_UNLOCK(sc->gif_ro.ro_rt);
 228         }
 229
 230         error = ip_output(m, NULL, &sc->gif_ro, IP_OUTARGS, NULL, &ipoa);
 231
 232         return (error);
 233 }
 234
 235 void
 236 in_gif_input(struct mbuf *m, int off)
 237 {
 238         struct ifnet *gifp = NULL;
 239         struct ip *ip;
 240         int af, proto;
 241         u_int8_t otos, old_tos;
 242         int egress_success = 0;
 243         int sum;
 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                         old_tos = ip->ip_tos;
 273                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &ip->ip_tos);
 274                         if (old_tos != ip->ip_tos) {
 275                             sum = ~ntohs(ip->ip_sum) & 0xffff;
 276                             sum += (~otos & 0xffff) + ip->ip_tos;
 277                             sum = (sum >> 16) + (sum & 0xffff);
 278                             sum += (sum >> 16);  /* add carry */
 279                             ip->ip_sum = htons(~sum & 0xffff);
 280                         }
 281                 } else
 282                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 283                 break;
 284             }
 285 #endif
 286 #if INET6
 287         case IPPROTO_IPV6:
 288             {
 289                 struct ip6_hdr *ip6;
 290                 u_int8_t itos;
 291                 af = AF_INET6;
 292                 if (mbuf_len(m) < sizeof (*ip6)) {
 293                         m = m_pullup(m, sizeof (*ip6));
 294                         if (!m)
 295                                 return;
 296                 }
 297                 ip6 = mtod(m, struct ip6_hdr *);
 298                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 299                 if (gifp->if_flags & IFF_LINK1)
 300                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &itos);
 301                 else
 302                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 303                 ip6->ip6_flow &= ~htonl(0xff << 20);
 304                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 305                 break;
 306             }
 307 #endif /* INET6 */
 308         default:
 309                 OSAddAtomic(1, &ipstat.ips_nogif);
 310                 m_freem(m);
 311                 return;
 312         }
 313
 314         if (egress_success == 0) {
 315                 OSAddAtomic(1, &ipstat.ips_nogif);
 316                 m_freem(m);
 317                 return;
 318         }
 319
 320 #ifdef __APPLE__
 321         /* Replace the rcvif by gifp for dlil to route it correctly */
 322         if (m->m_pkthdr.rcvif)
 323                 m->m_pkthdr.rcvif = gifp;
 324         ifnet_input(gifp, m, NULL);
 325 #else
 326         gif_input(m, af, gifp);
 327 #endif
 328 }
 329
 330 /*
 331  * We know that we are in IFF_UP, outer address available, and outer family
 332  * matched the physical addr family.  see gif_encapcheck().
 333  */
 334 int
 335 gif_encapcheck4(
 336         const struct mbuf *m,
 337         __unused int off,
 338         __unused int proto,
 339         void *arg)
 340 {
 341         struct ip ip;
 342         struct gif_softc *sc;
 343         struct sockaddr_in *src, *dst;
 344         int addrmatch;
 345         struct in_ifaddr *ia4;
 346
 347         /* sanity check done in caller */
 348         sc = (struct gif_softc *)arg;
 349         src = (struct sockaddr_in *)(void *)sc->gif_psrc;
 350         dst = (struct sockaddr_in *)(void *)sc->gif_pdst;
 351
 352         GIF_LOCK_ASSERT(sc);
 353
 354         mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof (ip), &ip);
 355
 356         /* check for address match */
 357         addrmatch = 0;
 358         if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
 359                 addrmatch |= 1;
 360         if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
 361                 addrmatch |= 2;
 362         if (addrmatch != 3)
 363                 return (0);
 364
 365         /* martian filters on outer source - NOT done in ip_input! */
 366         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
 367                 return (0);
 368         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 369         case 0: case 127: case 255:
 370                 return (0);
 371         }
 372         /* reject packets with broadcast on source */
 373         lck_rw_lock_shared(in_ifaddr_rwlock);
 374         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 375             ia4 = TAILQ_NEXT(ia4, ia_link)) {
 376                 if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0)
 377                         continue;
 378                 IFA_LOCK(&ia4->ia_ifa);
 379                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 380                         IFA_UNLOCK(&ia4->ia_ifa);
 381                         lck_rw_done(in_ifaddr_rwlock);
 382                         return (0);
 383                 }
 384                 IFA_UNLOCK(&ia4->ia_ifa);
 385         }
 386         lck_rw_done(in_ifaddr_rwlock);
 387
 388         /* ingress filters on outer source */
 389         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
 390             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 391                 struct sockaddr_in sin;
 392                 struct rtentry *rt;
 393
 394                 bzero(&sin, sizeof (sin));
 395                 sin.sin_family = AF_INET;
 396                 sin.sin_len = sizeof (struct sockaddr_in);
 397                 sin.sin_addr = ip.ip_src;
 398                 rt = rtalloc1_scoped((struct sockaddr *)&sin, 0, 0,
 399                     m->m_pkthdr.rcvif->if_index);
 400                 if (rt != NULL)
 401                         RT_LOCK(rt);
 402                 if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
 403                         if (rt != NULL) {
 404                                 RT_UNLOCK(rt);
 405                                 rtfree(rt);
 406                         }
 407                         return (0);
 408                 }
 409                 RT_UNLOCK(rt);
 410                 rtfree(rt);
 411         }
 412
 413         return (32 * 2);
 414 }