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 #include <netinet/ip6.h>
  85
  86 #include <net/if_gif.h>
  87
  88 #include <net/net_osdep.h>
  89
  90 int ip_gif_ttl = GIF_TTL;
  91 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW | CTLFLAG_LOCKED,
  92     &ip_gif_ttl, 0, "");
  93
  94 int
  95 in_gif_output(
  96         struct ifnet    *ifp,
  97         int             family,
  98         struct mbuf     *m,
  99         __unused struct rtentry *rt)
 100 {
 101         struct gif_softc *sc = ifnet_softc(ifp);
 102         struct sockaddr_in *dst = (struct sockaddr_in *)
 103             (void *)&sc->gif_ro.ro_dst;
 104         struct sockaddr_in *sin_src = (struct sockaddr_in *)
 105             (void *)sc->gif_psrc;
 106         struct sockaddr_in *sin_dst = (struct sockaddr_in *)
 107             (void *)sc->gif_pdst;
 108         struct ip iphdr;        /* capsule IP header, host byte ordered */
 109         int proto, error;
 110         u_int8_t tos;
 111         struct ip_out_args ipoa;
 112
 113         bzero(&ipoa, sizeof(ipoa));
 114         ipoa.ipoa_boundif = IFSCOPE_NONE;
 115         ipoa.ipoa_flags = IPOAF_SELECT_SRCIF;
 116         ipoa.ipoa_sotc = SO_TC_UNSPEC;
 117         ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC;
 118
 119         GIF_LOCK_ASSERT(sc);
 120
 121         if (sin_src == NULL || sin_dst == NULL ||
 122             sin_src->sin_family != AF_INET ||
 123             sin_dst->sin_family != AF_INET) {
 124                 m_freem(m);
 125                 return EAFNOSUPPORT;
 126         }
 127
 128         switch (family) {
 129 #if INET
 130         case AF_INET:
 131         {
 132                 struct ip *ip;
 133
 134                 proto = IPPROTO_IPV4;
 135                 if (mbuf_len(m) < sizeof(*ip)) {
 136                         m = m_pullup(m, sizeof(*ip));
 137                         if (!m) {
 138                                 return ENOBUFS;
 139                         }
 140                 }
 141                 ip = mtod(m, struct ip *);
 142                 tos = ip->ip_tos;
 143                 break;
 144         }
 145 #endif /* INET */
 146         case AF_INET6:
 147         {
 148                 struct ip6_hdr *ip6;
 149                 proto = IPPROTO_IPV6;
 150                 if (mbuf_len(m) < sizeof(*ip6)) {
 151                         m = m_pullup(m, sizeof(*ip6));
 152                         if (!m) {
 153                                 return ENOBUFS;
 154                         }
 155                 }
 156                 ip6 = mtod(m, struct ip6_hdr *);
 157                 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 158                 break;
 159         }
 160         default:
 161 #if DEBUG
 162                 printf("in_gif_output: warning: unknown family %d passed\n",
 163                     family);
 164 #endif
 165                 m_freem(m);
 166                 return EAFNOSUPPORT;
 167         }
 168
 169         bzero(&iphdr, sizeof(iphdr));
 170         iphdr.ip_src = sin_src->sin_addr;
 171         /* bidirectional configured tunnel mode */
 172         if (sin_dst->sin_addr.s_addr != INADDR_ANY) {
 173                 iphdr.ip_dst = sin_dst->sin_addr;
 174         } else {
 175                 m_freem(m);
 176                 return ENETUNREACH;
 177         }
 178         iphdr.ip_p = proto;
 179         /* version will be set in ip_output() */
 180         iphdr.ip_ttl = ip_gif_ttl;
 181         iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
 182         if (ifp->if_flags & IFF_LINK1) {
 183                 ip_ecn_ingress(ECN_NORMAL, &iphdr.ip_tos, &tos);
 184         } else {
 185                 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
 186         }
 187
 188         /* prepend new IP header */
 189         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT, 0);
 190         if (m && mbuf_len(m) < sizeof(struct ip)) {
 191                 m = m_pullup(m, sizeof(struct ip));
 192         }
 193         if (m == NULL) {
 194                 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
 195                 return ENOBUFS;
 196         }
 197         bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
 198
 199         if (ROUTE_UNUSABLE(&sc->gif_ro) ||
 200             dst->sin_family != sin_dst->sin_family ||
 201             dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
 202             (sc->gif_ro.ro_rt != NULL && sc->gif_ro.ro_rt->rt_ifp == ifp)) {
 203                 /* cache route doesn't match or recursive route */
 204                 dst->sin_family = sin_dst->sin_family;
 205                 dst->sin_len = sizeof(struct sockaddr_in);
 206                 dst->sin_addr = sin_dst->sin_addr;
 207                 ROUTE_RELEASE(&sc->gif_ro);
 208 #if 0
 209                 sc->gif_if.if_mtu = GIF_MTU;
 210 #endif
 211         }
 212
 213         if (sc->gif_ro.ro_rt == NULL) {
 214                 rtalloc(&sc->gif_ro);
 215                 if (sc->gif_ro.ro_rt == NULL) {
 216                         m_freem(m);
 217                         return ENETUNREACH;
 218                 }
 219
 220                 /* if it constitutes infinite encapsulation, punt. */
 221                 RT_LOCK(sc->gif_ro.ro_rt);
 222                 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
 223                         RT_UNLOCK(sc->gif_ro.ro_rt);
 224                         m_freem(m);
 225                         return ENETUNREACH; /* XXX */
 226                 }
 227 #if 0
 228                 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
 229                     - sizeof(struct ip);
 230 #endif
 231                 RT_UNLOCK(sc->gif_ro.ro_rt);
 232         }
 233
 234         error = ip_output(m, NULL, &sc->gif_ro, IP_OUTARGS, NULL, &ipoa);
 235
 236         return error;
 237 }
 238
 239 void
 240 in_gif_input(struct mbuf *m, int off)
 241 {
 242         struct ifnet *gifp = NULL;
 243         struct ip *ip;
 244         int af, proto;
 245         u_int8_t otos, old_tos;
 246         int egress_success = 0;
 247         int sum;
 248
 249         ip = mtod(m, struct ip *);
 250         proto = ip->ip_p;
 251
 252
 253         gifp = ((struct gif_softc *)encap_getarg(m))->gif_if;
 254
 255         if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
 256                 m_freem(m);
 257                 OSAddAtomic(1, &ipstat.ips_nogif);
 258                 return;
 259         }
 260
 261         otos = ip->ip_tos;
 262         m_adj(m, off);
 263
 264         switch (proto) {
 265 #if INET
 266         case IPPROTO_IPV4:
 267         {
 268                 af = AF_INET;
 269                 if (mbuf_len(m) < sizeof(*ip)) {
 270                         m = m_pullup(m, sizeof(*ip));
 271                         if (!m) {
 272                                 return;
 273                         }
 274                 }
 275                 ip = mtod(m, struct ip *);
 276                 if (gifp->if_flags & IFF_LINK1) {
 277                         old_tos = ip->ip_tos;
 278                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &ip->ip_tos);
 279                         if (old_tos != ip->ip_tos) {
 280                                 sum = ~ntohs(ip->ip_sum) & 0xffff;
 281                                 sum += (~otos & 0xffff) + ip->ip_tos;
 282                                 sum = (sum >> 16) + (sum & 0xffff);
 283                                 sum += (sum >> 16); /* add carry */
 284                                 ip->ip_sum = htons(~sum & 0xffff);
 285                         }
 286                 } else {
 287                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
 288                 }
 289                 break;
 290         }
 291 #endif
 292         case IPPROTO_IPV6:
 293         {
 294                 struct ip6_hdr *ip6;
 295                 u_int8_t itos;
 296                 af = AF_INET6;
 297                 if (mbuf_len(m) < sizeof(*ip6)) {
 298                         m = m_pullup(m, sizeof(*ip6));
 299                         if (!m) {
 300                                 return;
 301                         }
 302                 }
 303                 ip6 = mtod(m, struct ip6_hdr *);
 304                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 305                 if (gifp->if_flags & IFF_LINK1) {
 306                         egress_success = ip_ecn_egress(ECN_NORMAL, &otos, &itos);
 307                 } else {
 308                         egress_success = ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 309                 }
 310                 ip6->ip6_flow &= ~htonl(0xff << 20);
 311                 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 312                 break;
 313         }
 314         default:
 315                 OSAddAtomic(1, &ipstat.ips_nogif);
 316                 m_freem(m);
 317                 return;
 318         }
 319
 320         if (egress_success == 0) {
 321                 OSAddAtomic(1, &ipstat.ips_nogif);
 322                 m_freem(m);
 323                 return;
 324         }
 325
 326 #ifdef __APPLE__
 327         /* Replace the rcvif by gifp for dlil to route it correctly */
 328         if (m->m_pkthdr.rcvif) {
 329                 m->m_pkthdr.rcvif = gifp;
 330         }
 331         ifnet_input(gifp, m, NULL);
 332 #else
 333         gif_input(m, af, gifp);
 334 #endif
 335 }
 336
 337 /*
 338  * We know that we are in IFF_UP, outer address available, and outer family
 339  * matched the physical addr family.  see gif_encapcheck().
 340  */
 341 int
 342 gif_encapcheck4(
 343         const struct mbuf *m,
 344         __unused int off,
 345         __unused int proto,
 346         void *arg)
 347 {
 348         struct ip ip;
 349         struct gif_softc *sc;
 350         struct sockaddr_in *src, *dst;
 351         int addrmatch;
 352         struct in_ifaddr *ia4;
 353
 354         /* sanity check done in caller */
 355         sc = (struct gif_softc *)arg;
 356         src = (struct sockaddr_in *)(void *)sc->gif_psrc;
 357         dst = (struct sockaddr_in *)(void *)sc->gif_pdst;
 358
 359         GIF_LOCK_ASSERT(sc);
 360
 361         mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof(ip), &ip);
 362
 363         /* check for address match */
 364         addrmatch = 0;
 365         if (src->sin_addr.s_addr == ip.ip_dst.s_addr) {
 366                 addrmatch |= 1;
 367         }
 368         if (dst->sin_addr.s_addr == ip.ip_src.s_addr) {
 369                 addrmatch |= 2;
 370         }
 371         if (addrmatch != 3) {
 372                 return 0;
 373         }
 374
 375         /* martian filters on outer source - NOT done in ip_input! */
 376         if (IN_MULTICAST(ntohl(ip.ip_src.s_addr))) {
 377                 return 0;
 378         }
 379         switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
 380         case 0: case 127: case 255:
 381                 return 0;
 382         }
 383         /* reject packets with broadcast on source */
 384         lck_rw_lock_shared(in_ifaddr_rwlock);
 385         for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
 386             ia4 = TAILQ_NEXT(ia4, ia_link)) {
 387                 if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0) {
 388                         continue;
 389                 }
 390                 IFA_LOCK(&ia4->ia_ifa);
 391                 if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
 392                         IFA_UNLOCK(&ia4->ia_ifa);
 393                         lck_rw_done(in_ifaddr_rwlock);
 394                         return 0;
 395                 }
 396                 IFA_UNLOCK(&ia4->ia_ifa);
 397         }
 398         lck_rw_done(in_ifaddr_rwlock);
 399
 400         /* ingress filters on outer source */
 401         if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
 402             (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
 403                 struct sockaddr_in sin;
 404                 struct rtentry *rt;
 405
 406                 bzero(&sin, sizeof(sin));
 407                 sin.sin_family = AF_INET;
 408                 sin.sin_len = sizeof(struct sockaddr_in);
 409                 sin.sin_addr = ip.ip_src;
 410                 rt = rtalloc1_scoped((struct sockaddr *)&sin, 0, 0,
 411                     m->m_pkthdr.rcvif->if_index);
 412                 if (rt != NULL) {
 413                         RT_LOCK(rt);
 414                 }
 415                 if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
 416                         if (rt != NULL) {
 417                                 RT_UNLOCK(rt);
 418                                 rtfree(rt);
 419                         }
 420                         return 0;
 421                 }
 422                 RT_UNLOCK(rt);
 423                 rtfree(rt);
 424         }
 425
 426         return 32 * 2;
 427 }