sys/netproto/ipsec/xform_ipip.c

   1 /*      $FreeBSD: src/sys/netipsec/xform_ipip.c,v 1.3.2.1 2003/01/24 05:11:36 sam Exp $ */
   2 /*      $DragonFly: src/sys/netproto/ipsec/xform_ipip.c,v 1.15 2008/11/01 04:22:15 sephe Exp $  */
   3 /*      $OpenBSD: ip_ipip.c,v 1.25 2002/06/10 18:04:55 itojun Exp $ */
   4 /*
   5  * The authors of this code are John Ioannidis (ji@tla.org),
   6  * Angelos D. Keromytis (kermit@csd.uch.gr) and
   7  * Niels Provos (provos@physnet.uni-hamburg.de).
   8  *
   9  * The original version of this code was written by John Ioannidis
  10  * for BSD/OS in Athens, Greece, in November 1995.
  11  *
  12  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
  13  * by Angelos D. Keromytis.
  14  *
  15  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
  16  * and Niels Provos.
  17  *
  18  * Additional features in 1999 by Angelos D. Keromytis.
  19  *
  20  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
  21  * Angelos D. Keromytis and Niels Provos.
  22  * Copyright (c) 2001, Angelos D. Keromytis.
  23  *
  24  * Permission to use, copy, and modify this software with or without fee
  25  * is hereby granted, provided that this entire notice is included in
  26  * all copies of any software which is or includes a copy or
  27  * modification of this software.
  28  * You may use this code under the GNU public license if you so wish. Please
  29  * contribute changes back to the authors under this freer than GPL license
  30  * so that we may further the use of strong encryption without limitations to
  31  * all.
  32  *
  33  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
  34  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
  35  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
  36  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
  37  * PURPOSE.
  38  */
  39
  40 /*
  41  * IP-inside-IP processing
  42  */
  43 #include "opt_inet.h"
  44 #include "opt_inet6.h"
  45
  46 #include <sys/param.h>
  47 #include <sys/systm.h>
  48 #include <sys/mbuf.h>
  49 #include <sys/socket.h>
  50 #include <sys/kernel.h>
  51 #include <sys/protosw.h>
  52 #include <sys/sysctl.h>
  53
  54 #include <net/if.h>
  55 #include <net/route.h>
  56 #include <net/netisr.h>
  57
  58 #include <netinet/in.h>
  59 #include <netinet/in_systm.h>
  60 #include <netinet/in_var.h>
  61 #include <netinet/ip.h>
  62 #include <netinet/ip_ecn.h>
  63 #include <netinet/ip_var.h>
  64 #include <netinet/ip_encap.h>
  65
  66 #include <netproto/ipsec/ipsec.h>
  67 #include <netproto/ipsec/xform.h>
  68
  69 #include <netproto/ipsec/ipip_var.h>
  70
  71 #ifdef MROUTING
  72 #include <netinet/ip_mroute.h>
  73 #endif
  74
  75 #ifdef INET6
  76 #include <netinet/ip6.h>
  77 #include <netproto/ipsec/ipsec6.h>
  78 #include <netinet6/ip6_ecn.h>
  79 #include <netinet6/in6_var.h>
  80 #include <netinet6/ip6protosw.h>
  81 #endif
  82
  83 #include <netproto/ipsec/key.h>
  84 #include <netproto/ipsec/key_debug.h>
  85
  86 #include <machine/stdarg.h>
  87
  88 typedef void    pr_in_input_t (struct mbuf *, int, int); /* XXX FIX THIS */
  89
  90 /*
  91  * We can control the acceptance of IP4 packets by altering the sysctl
  92  * net.inet.ipip.allow value.  Zero means drop them, all else is acceptance.
  93  */
  94 int     ipip_allow = 0;
  95 struct  ipipstat ipipstat;
  96
  97 SYSCTL_DECL(_net_inet_ipip);
  98 SYSCTL_INT(_net_inet_ipip, OID_AUTO,
  99         ipip_allow,     CTLFLAG_RW,     &ipip_allow,    0, "");
 100 SYSCTL_STRUCT(_net_inet_ipip, IPSECCTL_STATS,
 101         stats,          CTLFLAG_RD,     &ipipstat,      ipipstat, "");
 102
 103 /* XXX IPCOMP */
 104 #define M_IPSEC (M_AUTHIPHDR|M_AUTHIPDGM|M_DECRYPTED)
 105
 106 static void _ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp);
 107
 108 #ifdef INET6
 109 /*
 110  * Really only a wrapper for ipip_input(), for use with IPv6.
 111  */
 112 int
 113 ip4_input6(struct mbuf **m, int *offp, int proto)
 114 {
 115 #if 0
 116         /* If we do not accept IP-in-IP explicitly, drop.  */
 117         if (!ipip_allow && ((*m)->m_flags & M_IPSEC) == 0) {
 118                 DPRINTF(("ip4_input6: dropped due to policy\n"));
 119                 ipipstat.ipips_pdrops++;
 120                 m_freem(*m);
 121                 return IPPROTO_DONE;
 122         }
 123 #endif
 124         _ipip_input(*m, *offp, NULL);
 125         return IPPROTO_DONE;
 126 }
 127 #endif /* INET6 */
 128
 129 #ifdef INET
 130 /*
 131  * Really only a wrapper for ipip_input(), for use with IPv4.
 132  */
 133 void
 134 ip4_input(struct mbuf *m, ...)
 135 {
 136         __va_list ap;
 137         int iphlen;
 138
 139 #if 0
 140         /* If we do not accept IP-in-IP explicitly, drop.  */
 141         if (!ipip_allow && (m->m_flags & M_IPSEC) == 0) {
 142                 DPRINTF(("ip4_input: dropped due to policy\n"));
 143                 ipipstat.ipips_pdrops++;
 144                 m_freem(m);
 145                 return;
 146         }
 147 #endif
 148         __va_start(ap, m);
 149         iphlen = __va_arg(ap, int);
 150         __va_end(ap);
 151
 152         _ipip_input(m, iphlen, NULL);
 153 }
 154 #endif /* INET */
 155
 156 /*
 157  * ipip_input gets called when we receive an IP{46} encapsulated packet,
 158  * either because we got it at a real interface, or because AH or ESP
 159  * were being used in tunnel mode (in which case the rcvif element will
 160  * contain the address of the encX interface associated with the tunnel.
 161  */
 162
 163 static void
 164 _ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp)
 165 {
 166         struct sockaddr_in *sin;
 167         struct ifnet *ifp;
 168         struct ifaddr *ifa;
 169         struct ip *ipo;
 170 #ifdef INET6
 171         struct sockaddr_in6 *sin6;
 172         struct ip6_hdr *ip6 = NULL;
 173         u_int8_t itos;
 174 #endif
 175         u_int8_t nxt;
 176         int isr;
 177         u_int8_t otos;
 178         u_int8_t v;
 179         int hlen;
 180
 181         ipipstat.ipips_ipackets++;
 182
 183         m_copydata(m, 0, 1, &v);
 184
 185         switch (v >> 4) {
 186 #ifdef INET
 187         case 4:
 188                 hlen = sizeof(struct ip);
 189                 break;
 190 #endif /* INET */
 191 #ifdef INET6
 192         case 6:
 193                 hlen = sizeof(struct ip6_hdr);
 194                 break;
 195 #endif
 196         default:
 197                 DPRINTF(("_ipip_input: bad protocol version 0x%x (%u) "
 198                         "for outer header\n", v, v>>4));
 199                 ipipstat.ipips_family++;
 200                 m_freem(m);
 201                 return /* EAFNOSUPPORT */;
 202         }
 203
 204         /* Bring the IP header in the first mbuf, if not there already */
 205         if (m->m_len < hlen) {
 206                 if ((m = m_pullup(m, hlen)) == NULL) {
 207                         DPRINTF(("ipip_input: m_pullup (1) failed\n"));
 208                         ipipstat.ipips_hdrops++;
 209                         return;
 210                 }
 211         }
 212
 213         ipo = mtod(m, struct ip *);
 214
 215 #ifdef MROUTING
 216         if (ipo->ip_v == IPVERSION && ipo->ip_p == IPPROTO_IPV4) {
 217                 if (IN_MULTICAST(((struct ip *)((char *) ipo + iphlen))->ip_dst.s_addr)) {
 218                         ipip_mroute_input (m, iphlen);
 219                         return;
 220                 }
 221         }
 222 #endif /* MROUTING */
 223
 224         /* Keep outer ecn field. */
 225         switch (v >> 4) {
 226 #ifdef INET
 227         case 4:
 228                 otos = ipo->ip_tos;
 229                 break;
 230 #endif /* INET */
 231 #ifdef INET6
 232         case 6:
 233                 otos = (ntohl(mtod(m, struct ip6_hdr *)->ip6_flow) >> 20) & 0xff;
 234                 break;
 235 #endif
 236         default:
 237                 panic("ipip_input: unknown ip version %u (outer)", v>>4);
 238         }
 239
 240         /* Remove outer IP header */
 241         m_adj(m, iphlen);
 242
 243         /* Sanity check */
 244         if (m->m_pkthdr.len < sizeof(struct ip))  {
 245                 ipipstat.ipips_hdrops++;
 246                 m_freem(m);
 247                 return;
 248         }
 249
 250         m_copydata(m, 0, 1, &v);
 251
 252         switch (v >> 4) {
 253 #ifdef INET
 254         case 4:
 255                 hlen = sizeof(struct ip);
 256                 break;
 257 #endif /* INET */
 258
 259 #ifdef INET6
 260         case 6:
 261                 hlen = sizeof(struct ip6_hdr);
 262                 break;
 263 #endif
 264         default:
 265                 DPRINTF(("_ipip_input: bad protocol version 0x%x (%u) "
 266                         "for inner header\n", v, v>>4));
 267                 ipipstat.ipips_family++;
 268                 m_freem(m);
 269                 return; /* EAFNOSUPPORT */
 270         }
 271
 272         /*
 273          * Bring the inner IP header in the first mbuf, if not there already.
 274          */
 275         if (m->m_len < hlen) {
 276                 if ((m = m_pullup(m, hlen)) == NULL) {
 277                         DPRINTF(("ipip_input: m_pullup (2) failed\n"));
 278                         ipipstat.ipips_hdrops++;
 279                         return;
 280                 }
 281         }
 282
 283         /*
 284          * RFC 1853 specifies that the inner TTL should not be touched on
 285          * decapsulation. There's no reason this comment should be here, but
 286          * this is as good as any a position.
 287          */
 288
 289         /* Some sanity checks in the inner IP header */
 290         switch (v >> 4) {
 291 #ifdef INET
 292         case 4:
 293                 ipo = mtod(m, struct ip *);
 294                 nxt = ipo->ip_p;
 295                 ip_ecn_egress(ip4_ipsec_ecn, &otos, &ipo->ip_tos);
 296                 break;
 297 #endif /* INET */
 298 #ifdef INET6
 299         case 6:
 300                 ip6 = (struct ip6_hdr *) ipo;
 301                 nxt = ip6->ip6_nxt;
 302                 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 303                 ip_ecn_egress(ip6_ipsec_ecn, &otos, &itos);
 304                 ip6->ip6_flow &= ~htonl(0xff << 20);
 305                 ip6->ip6_flow |= htonl((u_int32_t) itos << 20);
 306                 break;
 307 #endif
 308         default:
 309                 panic("ipip_input: unknown ip version %u (inner)", v>>4);
 310         }
 311
 312         /* Check for local address spoofing. */
 313         if ((m->m_pkthdr.rcvif == NULL ||
 314             !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) &&
 315             ipip_allow != 2) {
 316                 TAILQ_FOREACH(ifp, &ifnet, if_link) {
 317                         TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_link) {
 318 #ifdef INET
 319                                 if (ipo) {
 320                                         if (ifa->ifa_addr->sa_family !=
 321                                             AF_INET)
 322                                                 continue;
 323
 324                                         sin = (struct sockaddr_in *) ifa->ifa_addr;
 325
 326                                         if (sin->sin_addr.s_addr ==
 327                                             ipo->ip_src.s_addr) {
 328                                                 ipipstat.ipips_spoof++;
 329                                                 m_freem(m);
 330                                                 return;
 331                                         }
 332                                 }
 333 #endif /* INET */
 334
 335 #ifdef INET6
 336                                 if (ip6) {
 337                                         if (ifa->ifa_addr->sa_family !=
 338                                             AF_INET6)
 339                                                 continue;
 340
 341                                         sin6 = (struct sockaddr_in6 *) ifa->ifa_addr;
 342
 343                                         if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &ip6->ip6_src)) {
 344                                                 ipipstat.ipips_spoof++;
 345                                                 m_freem(m);
 346                                                 return;
 347                                         }
 348
 349                                 }
 350 #endif /* INET6 */
 351                         }
 352                 }
 353         }
 354
 355         /* Statistics */
 356         ipipstat.ipips_ibytes += m->m_pkthdr.len - iphlen;
 357
 358         /*
 359          * Interface pointer stays the same; if no IPsec processing has
 360          * been done (or will be done), this will point to a normal
 361          * interface. Otherwise, it'll point to an enc interface, which
 362          * will allow a packet filter to distinguish between secure and
 363          * untrusted packets.
 364          */
 365
 366         switch (v >> 4) {
 367 #ifdef INET
 368         case 4:
 369                 isr = NETISR_IP;
 370                 break;
 371 #endif
 372 #ifdef INET6
 373         case 6:
 374                 isr = NETISR_IPV6;
 375                 break;
 376 #endif
 377         default:
 378                 panic("ipip_input: should never reach here");
 379         }
 380
 381         if (netisr_queue(isr, m)) {
 382                 ipipstat.ipips_qfull++;
 383
 384                 DPRINTF(("ipip_input: packet dropped because of full queue\n"));
 385         }
 386 }
 387
 388 int
 389 ipip_output(
 390         struct mbuf *m,
 391         struct ipsecrequest *isr,
 392         struct mbuf **mp,
 393         int skip,
 394         int protoff
 395 )
 396 {
 397         struct secasvar *sav;
 398         u_int8_t tp, otos;
 399         struct secasindex *saidx;
 400         int error;
 401 #ifdef INET
 402         u_int8_t itos;
 403         struct ip *ipo;
 404 #endif /* INET */
 405 #ifdef INET6
 406         struct ip6_hdr *ip6, *ip6o;
 407 #endif /* INET6 */
 408
 409         sav = isr->sav;
 410         KASSERT(sav != NULL, ("ipip_output: null SA"));
 411         KASSERT(sav->sah != NULL, ("ipip_output: null SAH"));
 412
 413         /* XXX Deal with empty TDB source/destination addresses. */
 414
 415         m_copydata(m, 0, 1, &tp);
 416         tp = (tp >> 4) & 0xff;  /* Get the IP version number. */
 417
 418         saidx = &sav->sah->saidx;
 419         switch (saidx->dst.sa.sa_family) {
 420 #ifdef INET
 421         case AF_INET:
 422                 if (saidx->src.sa.sa_family != AF_INET ||
 423                     saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
 424                     saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) {
 425                         DPRINTF(("ipip_output: unspecified tunnel endpoint "
 426                             "address in SA %s/%08lx\n",
 427                             ipsec_address(&saidx->dst),
 428                             (u_long) ntohl(sav->spi)));
 429                         ipipstat.ipips_unspec++;
 430                         error = EINVAL;
 431                         goto bad;
 432                 }
 433
 434                 M_PREPEND(m, sizeof(struct ip), MB_DONTWAIT);
 435                 if (m == 0) {
 436                         DPRINTF(("ipip_output: M_PREPEND failed\n"));
 437                         ipipstat.ipips_hdrops++;
 438                         error = ENOBUFS;
 439                         goto bad;
 440                 }
 441
 442                 ipo = mtod(m, struct ip *);
 443
 444                 ipo->ip_v = IPVERSION;
 445                 ipo->ip_hl = 5;
 446                 ipo->ip_len = htons(m->m_pkthdr.len);
 447                 ipo->ip_ttl = ip_defttl;
 448                 ipo->ip_sum = 0;
 449                 ipo->ip_src = saidx->src.sin.sin_addr;
 450                 ipo->ip_dst = saidx->dst.sin.sin_addr;
 451
 452                 ipo->ip_id = ip_newid();
 453
 454                 /* If the inner protocol is IP... */
 455                 if (tp == IPVERSION) {
 456                         /* Save ECN notification */
 457                         m_copydata(m, sizeof(struct ip) +
 458                             offsetof(struct ip, ip_tos),
 459                             sizeof(u_int8_t), (caddr_t) &itos);
 460
 461                         ipo->ip_p = IPPROTO_IPIP;
 462
 463                         /*
 464                          * We should be keeping tunnel soft-state and
 465                          * send back ICMPs if needed.
 466                          */
 467                         m_copydata(m, sizeof(struct ip) +
 468                             offsetof(struct ip, ip_off),
 469                             sizeof(u_int16_t), (caddr_t) &ipo->ip_off);
 470                         ipo->ip_off = ntohs(ipo->ip_off);
 471                         ipo->ip_off &= ~(IP_DF | IP_MF | IP_OFFMASK);
 472                         ipo->ip_off = htons(ipo->ip_off);
 473                 }
 474 #ifdef INET6
 475                 else if (tp == (IPV6_VERSION >> 4)) {
 476                         u_int32_t itos32;
 477
 478                         /* Save ECN notification. */
 479                         m_copydata(m, sizeof(struct ip) +
 480                             offsetof(struct ip6_hdr, ip6_flow),
 481                             sizeof(u_int32_t), (caddr_t) &itos32);
 482                         itos = ntohl(itos32) >> 20;
 483                         ipo->ip_p = IPPROTO_IPV6;
 484                         ipo->ip_off = 0;
 485                 }
 486 #endif /* INET6 */
 487                 else {
 488                         goto nofamily;
 489                 }
 490
 491                 otos = 0;
 492                 ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
 493                 ipo->ip_tos = otos;
 494                 break;
 495 #endif /* INET */
 496
 497 #ifdef INET6
 498         case AF_INET6:
 499                 if (IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr) ||
 500                     saidx->src.sa.sa_family != AF_INET6 ||
 501                     IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr)) {
 502                         DPRINTF(("ipip_output: unspecified tunnel endpoint "
 503                             "address in SA %s/%08lx\n",
 504                             ipsec_address(&saidx->dst),
 505                             (u_long) ntohl(sav->spi)));
 506                         ipipstat.ipips_unspec++;
 507                         error = ENOBUFS;
 508                         goto bad;
 509                 }
 510
 511                 /* scoped address handling */
 512                 ip6 = mtod(m, struct ip6_hdr *);
 513                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
 514                         ip6->ip6_src.s6_addr16[1] = 0;
 515                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
 516                         ip6->ip6_dst.s6_addr16[1] = 0;
 517
 518                 M_PREPEND(m, sizeof(struct ip6_hdr), MB_DONTWAIT);
 519                 if (m == 0) {
 520                         DPRINTF(("ipip_output: M_PREPEND failed\n"));
 521                         ipipstat.ipips_hdrops++;
 522                         *mp = NULL;
 523                         error = ENOBUFS;
 524                         goto bad;
 525                 }
 526
 527                 /* Initialize IPv6 header */
 528                 ip6o = mtod(m, struct ip6_hdr *);
 529                 ip6o->ip6_flow = 0;
 530                 ip6o->ip6_vfc &= ~IPV6_VERSION_MASK;
 531                 ip6o->ip6_vfc |= IPV6_VERSION;
 532                 ip6o->ip6_plen = htons(m->m_pkthdr.len);
 533                 ip6o->ip6_hlim = ip_defttl;
 534                 ip6o->ip6_dst = saidx->dst.sin6.sin6_addr;
 535                 ip6o->ip6_src = saidx->src.sin6.sin6_addr;
 536
 537 #ifdef INET
 538                 if (tp == IPVERSION) {
 539                         /* Save ECN notification */
 540                         m_copydata(m, sizeof(struct ip6_hdr) +
 541                             offsetof(struct ip, ip_tos), sizeof(u_int8_t),
 542                             (caddr_t) &itos);
 543
 544                         /* This is really IPVERSION. */
 545                         ip6o->ip6_nxt = IPPROTO_IPIP;
 546                 } else
 547 #endif /* INET */
 548                         if (tp == (IPV6_VERSION >> 4)) {
 549                                 u_int32_t itos32;
 550
 551                                 /* Save ECN notification. */
 552                                 m_copydata(m, sizeof(struct ip6_hdr) +
 553                                     offsetof(struct ip6_hdr, ip6_flow),
 554                                     sizeof(u_int32_t), (caddr_t) &itos32);
 555                                 itos = ntohl(itos32) >> 20;
 556
 557                                 ip6o->ip6_nxt = IPPROTO_IPV6;
 558                         } else {
 559                                 goto nofamily;
 560                         }
 561
 562                 otos = 0;
 563                 ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
 564                 ip6o->ip6_flow |= htonl((u_int32_t) otos << 20);
 565                 break;
 566 #endif /* INET6 */
 567
 568         default:
 569 nofamily:
 570                 DPRINTF(("ipip_output: unsupported protocol family %u\n",
 571                     saidx->dst.sa.sa_family));
 572                 ipipstat.ipips_family++;
 573                 error = EAFNOSUPPORT;           /* XXX diffs from openbsd */
 574                 goto bad;
 575         }
 576
 577         ipipstat.ipips_opackets++;
 578         *mp = m;
 579
 580 #ifdef INET
 581         if (saidx->dst.sa.sa_family == AF_INET) {
 582 #if 0
 583                 if (sav->tdb_xform->xf_type == XF_IP4)
 584                         tdb->tdb_cur_bytes +=
 585                             m->m_pkthdr.len - sizeof(struct ip);
 586 #endif
 587                 ipipstat.ipips_obytes += m->m_pkthdr.len - sizeof(struct ip);
 588         }
 589 #endif /* INET */
 590
 591 #ifdef INET6
 592         if (saidx->dst.sa.sa_family == AF_INET6) {
 593 #if 0
 594                 if (sav->tdb_xform->xf_type == XF_IP4)
 595                         tdb->tdb_cur_bytes +=
 596                             m->m_pkthdr.len - sizeof(struct ip6_hdr);
 597 #endif
 598                 ipipstat.ipips_obytes +=
 599                     m->m_pkthdr.len - sizeof(struct ip6_hdr);
 600         }
 601 #endif /* INET6 */
 602
 603         return 0;
 604 bad:
 605         if (m)
 606                 m_freem(m), *mp = NULL;
 607         return (error);
 608 }
 609
 610 #ifdef FAST_IPSEC
 611 static int
 612 ipe4_init(struct secasvar *sav, struct xformsw *xsp)
 613 {
 614         sav->tdb_xform = xsp;
 615         return 0;
 616 }
 617
 618 static int
 619 ipe4_zeroize(struct secasvar *sav)
 620 {
 621         sav->tdb_xform = NULL;
 622         return 0;
 623 }
 624
 625 static int
 626 ipe4_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
 627 {
 628         /* This is a rather serious mistake, so no conditional printing. */
 629         kprintf("ipe4_input: should never be called\n");
 630         if (m)
 631                 m_freem(m);
 632         return EOPNOTSUPP;
 633 }
 634
 635 static struct xformsw ipe4_xformsw = {
 636         XF_IP4,         0,              "IPv4 Simple Encapsulation",
 637         ipe4_init,      ipe4_zeroize,   ipe4_input,     ipip_output,
 638 };
 639
 640 extern struct domain inetdomain;
 641 static struct protosw ipe4_protosw[] = {
 642 { SOCK_RAW,     &inetdomain,    IPPROTO_IPV4,   PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 643   ip4_input,    0,              0,              rip_ctloutput,
 644   cpu0_soport,  NULL,
 645   0,            0,              0,              0,
 646   &rip_usrreqs
 647 },
 648 #ifdef INET6
 649 { SOCK_RAW,     &inetdomain,    IPPROTO_IPV6,   PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 650   ip4_input,
 651                 0,              0,              rip_ctloutput,
 652   cpu0_soport,
 653   0,            0,              0,              0,
 654   &rip_usrreqs
 655 }
 656 #endif
 657 };
 658
 659 /*
 660  * Check the encapsulated packet to see if we want it
 661  */
 662 static int
 663 ipe4_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
 664 {
 665         /*
 666          * Only take packets coming from IPSEC tunnels; the rest
 667          * must be handled by the gif tunnel code.  Note that we
 668          * also return a minimum priority when we want the packet
 669          * so any explicit gif tunnels take precedence.
 670          */
 671         return ((m->m_flags & M_IPSEC) != 0 ? 1 : 0);
 672 }
 673
 674 static void
 675 ipe4_attach(void)
 676 {
 677         xform_register(&ipe4_xformsw);
 678         /* attach to encapsulation framework */
 679         /* XXX save return cookie for detach on module remove */
 680         encap_attach_func(AF_INET, -1,
 681                 ipe4_encapcheck, (struct protosw*) &ipe4_protosw[0], NULL);
 682 #ifdef INET6
 683         encap_attach_func(AF_INET6, -1,
 684                 ipe4_encapcheck, (struct protosw*) &ipe4_protosw[1], NULL);
 685 #endif
 686 }
 687 SYSINIT(ipe4_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ipe4_attach, NULL);
 688 #endif  /* FAST_IPSEC */