bsd/netinet/in_gif.c

   1 /*
   2  * Copyright (c) 2000-2018 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
 115         bzero(&ipoa, sizeof(ipoa));
 116         ipoa.ipoa_boundif = IFSCOPE_NONE;
 117         ipoa.ipoa_flags = IPOAF_SELECT_SRCIF;
 118         ipoa.ipoa_sotc = SO_TC_UNSPEC;
 119         ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC;
 120
 121         GIF_LOCK_ASSERT(sc);
 122
 123         if (sin_src == NULL || sin_dst == NULL ||
 124             sin_src->sin_family != AF_INET ||
 125             sin_dst->sin_family != AF_INET) {
 126                 m_freem(m);
 127                 return EAFNOSUPPORT;
 128         }
 129
 130         switch (family) {
 131 #if INET
 132         case AF_INET:
 133         {
 134                 struct ip *ip;
 135
 136                 proto = IPPROTO_IPV4;
 137                 if (mbuf_len(m) < sizeof(*ip)) {
 138                         m = m_pullup(m, sizeof(*ip));
 139                         if (!m) {
 140                                 return ENOBUFS;
 141                         }
 142                 }
 143                 ip = mtod(m, struct ip *);
 144                 tos = ip->ip_tos;
 145                 break;
 146         }
 147 #endif /* INET */
 148 #if INET6
 149         case AF_INET6:
 150         {
 151                 struct ip6_hdr *ip6;
 152                 proto = IPPROTO_IPV6;
 153                 if (mbuf_len(m) < sizeof(*ip6)) {
 154                         m = m_pullup(m, sizeof(*ip6));
 155                         if (!m) {
 156                                 return ENOBUFS;
 157                         }
 158                 }
 159                 ip6 = mtod(m, struct ip6_hdr *);
 160                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 161                 break;
 162         }
 163 #endif /* INET6 */
 164         default:
 165 #if DEBUG
 166                 printf("in_gif_output: warning: unknown family %d passed\n",
 167                     family);
 168 #endif
 169                 m_freem(m);
 170                 return EAFNOSUPPORT;
 171         }
 172
 173         bzero(&iphdr, sizeof(iphdr));
 174         iphdr.ip_src = sin_src->sin_addr;
 175         /* bidirectional configured tunnel mode */
 176         if (sin_dst->sin_addr.s_addr != INADDR_ANY) {
 177                 iphdr.ip_dst = sin_dst->sin_addr;
 178         } else {
 179                 m_freem(m);
 180                 return ENETUNREACH;
 181         }
 182         iphdr.ip_p = proto;
 183         /* version will be set in ip_output() */
 184         iphdr.ip_ttl = ip_gif_ttl;
 185         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
 186         if (ifp->if_flags & IFF_LINK1) {
 187                 ip_ecn_ingress(ECN_NORMAL, &iphdr.ip_tos, &tos);
 188         } else {
 189                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 190         }
 191
 192         /* prepend new IP header */
 193         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT, 0);
 194         if (m && mbuf_len(m) < sizeof(struct ip)) {
 195                 m = m_pullup(m, sizeof(struct ip));
 196         }
 197         if (m == NULL) {
 198                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 199                 return ENOBUFS;
 200         }
 201         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 202
 203         if (ROUTE_UNUSABLE(&sc->gif_ro) ||
 204             dst->sin_family != sin_dst->sin_family ||
 205             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
 206             (sc->gif_ro.ro_rt != NULL && sc->gif_ro.ro_rt->rt_ifp == ifp)) {
 207                 /* cache route doesn't match or recursive route */
 208                 dst->sin_family = sin_dst->sin_family;
 209                 dst->sin_len = sizeof(struct sockaddr_in);
 210                 dst->sin_addr = sin_dst->sin_addr;
 211                 ROUTE_RELEASE(&sc->gif_ro);
 212 #if 0
 213                 sc->gif_if.if_mtu = GIF_MTU;
 214 #endif
 215         }
 216
 217         if (sc->gif_ro.ro_rt == NULL) {
 218                 rtalloc(&sc->gif_ro);
 219                 if (sc->gif_ro.ro_rt == NULL) {
 220                         m_freem(m);
 221                         return ENETUNREACH;
 222                 }
 223
 224                 /* if it constitutes infinite encapsulation, punt. */
 225                 RT_LOCK(sc->gif_ro.ro_rt);
 226                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 227                         RT_UNLOCK(sc->gif_ro.ro_rt);
 228                         m_freem(m);
 229                         return ENETUNREACH; /* XXX */
 230                 }
 231 #if 0
 232                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 233                     - sizeof(struct ip);
 234 #endif
 235                 RT_UNLOCK(sc->gif_ro.ro_rt);
 236         }
 237
 238         error = ip_output(m, NULL, &sc->gif_ro, IP_OUTARGS, NULL, &ipoa);
 239
 240         return error;
 241 }
 242
 243 void
 244 in_gif_input(struct mbuf *m, int off)
 245 {
 246         struct ifnet *gifp = NULL;
 247         struct ip *ip;
 248         int af, proto;
 249         u_int8_t otos, old_tos;
 250         int egress_success = 0;
 251         int sum;
 252
 253         ip = mtod(m, struct ip *);
 254         proto = ip->ip_p;
 255
 256
 257         gifp = ((struct gif_softc *)encap_getarg(m))->gif_if;
 258
 259         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 260                 m_freem(m);
 261                 OSAddAtomic(1, &ipstat.ips_nogif);
 262                 return;
 263         }
 264
 265         otos = ip->ip_tos;
 266         m_adj(m, off);
 267
 268         switch (proto) {
 269 #if INET
 270         case IPPROTO_IPV4:
 271         {
 272                 af = AF_INET;
 273                 if (mbuf_len(m) < sizeof(*ip)) {
 274                         m = m_pullup(m, sizeof(*ip));
 275                         if (!m) {
 276                                 return;
 277                         }
 278                 }
 279                 ip = mtod(m, struct ip *);
 280                 if (gifp->if_flags & IFF_LINK1) {
 281                         old_tos = ip->ip_tos;
 282                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &ip->ip_tos);
 283                         if (old_tos != ip->ip_tos) {
 284                                 sum = ~ntohs(ip->ip_sum) & 0xffff;
 285                                 sum += (~otos & 0xffff) + ip->ip_tos;
 286                                 sum = (sum >> 16) + (sum & 0xffff);
 287                                 sum += (sum >> 16); /* add carry */
 288                                 ip->ip_sum = htons(~sum & 0xffff);
 289                         }
 290                 } else {
 291                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 292                 }
 293                 break;
 294         }
 295 #endif
 296 #if INET6
 297         case IPPROTO_IPV6:
 298         {
 299                 struct ip6_hdr *ip6;
 300                 u_int8_t itos;
 301                 af = AF_INET6;
 302                 if (mbuf_len(m) < sizeof(*ip6)) {
 303                         m = m_pullup(m, sizeof(*ip6));
 304                         if (!m) {
 305                                 return;
 306                         }
 307                 }
 308                 ip6 = mtod(m, struct ip6_hdr *);
 309                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 310                 if (gifp->if_flags & IFF_LINK1) {
 311                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &itos);
 312                 } else {
 313                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 314                 }
 315                 ip6->ip6_flow &= ~htonl(0xff << 20);
 316                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 317                 break;
 318         }
 319 #endif /* INET6 */
 320         default:
 321                 OSAddAtomic(1, &ipstat.ips_nogif);
 322                 m_freem(m);
 323                 return;
 324         }
 325
 326         if (egress_success == 0) {
 327                 OSAddAtomic(1, &ipstat.ips_nogif);
 328                 m_freem(m);
 329                 return;
 330         }
 331
 332 #ifdef __APPLE__
 333         /* Replace the rcvif by gifp for dlil to route it correctly */
 334         if (m->m_pkthdr.rcvif) {
 335                 m->m_pkthdr.rcvif = gifp;
 336         }
 337         ifnet_input(gifp, m, NULL);
 338 #else
 339         gif_input(m, af, gifp);
 340 #endif
 341 }
 342
 343 /*
 344  * We know that we are in IFF_UP, outer address available, and outer family
 345  * matched the physical addr family.  see gif_encapcheck().
 346  */
 347 int
 348 gif_encapcheck4(
 349         const struct mbuf *m,
 350         __unused int off,
 351         __unused int proto,
 352         void *arg)
 353 {
 354         struct ip ip;
 355         struct gif_softc *sc;
 356         struct sockaddr_in *src, *dst;
 357         int addrmatch;
 358         struct in_ifaddr *ia4;
 359
 360         /* sanity check done in caller */
 361         sc = (struct gif_softc *)arg;
 362         src = (struct sockaddr_in *)(void *)sc->gif_psrc;
 363         dst = (struct sockaddr_in *)(void *)sc->gif_pdst;
 364
 365         GIF_LOCK_ASSERT(sc);
 366
 367         mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof(ip), &ip);
 368
 369         /* check for address match */
 370         addrmatch = 0;
 371         if (src->sin_addr.s_addr == ip.ip_dst.s_addr) {
 372                 addrmatch |= 1;
 373         }
 374         if (dst->sin_addr.s_addr == ip.ip_src.s_addr) {
 375                 addrmatch |= 2;
 376         }
 377         if (addrmatch != 3) {
 378                 return 0;
 379         }
 380
 381         /* martian filters on outer source - NOT done in ip_input! */
 382         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr))) {
 383                 return 0;
 384         }
 385         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 386         case 0: case 127: case 255:
 387                 return 0;
 388         }
 389         /* reject packets with broadcast on source */
 390         lck_rw_lock_shared(in_ifaddr_rwlock);
 391         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 392             ia4 = TAILQ_NEXT(ia4, ia_link)) {
 393                 if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0) {
 394                         continue;
 395                 }
 396                 IFA_LOCK(&ia4->ia_ifa);
 397                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 398                         IFA_UNLOCK(&ia4->ia_ifa);
 399                         lck_rw_done(in_ifaddr_rwlock);
 400                         return 0;
 401                 }
 402                 IFA_UNLOCK(&ia4->ia_ifa);
 403         }
 404         lck_rw_done(in_ifaddr_rwlock);
 405
 406         /* ingress filters on outer source */
 407         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
 408             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 409                 struct sockaddr_in sin;
 410                 struct rtentry *rt;
 411
 412                 bzero(&sin, sizeof(sin));
 413                 sin.sin_family = AF_INET;
 414                 sin.sin_len = sizeof(struct sockaddr_in);
 415                 sin.sin_addr = ip.ip_src;
 416                 rt = rtalloc1_scoped((struct sockaddr *)&sin, 0, 0,
 417                     m->m_pkthdr.rcvif->if_index);
 418                 if (rt != NULL) {
 419                         RT_LOCK(rt);
 420                 }
 421                 if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
 422                         if (rt != NULL) {
 423                                 RT_UNLOCK(rt);
 424                                 rtfree(rt);
 425                         }
 426                         return 0;
 427                 }
 428                 RT_UNLOCK(rt);
 429                 rtfree(rt);
 430         }
 431
 432         return 32 * 2;
 433 }