sys/netipsec/ipsec_output.c

   1 /*-
   2  * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 /*
  30  * IPsec output processing.
  31  */
  32 #include "opt_inet.h"
  33 #include "opt_inet6.h"
  34 #include "opt_ipsec.h"
  35 #include "opt_enc.h"
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/mbuf.h>
  40 #include <sys/domain.h>
  41 #include <sys/protosw.h>
  42 #include <sys/socket.h>
  43 #include <sys/errno.h>
  44 #include <sys/syslog.h>
  45
  46 #include <net/if.h>
  47 #include <net/route.h>
  48
  49 #include <netinet/in.h>
  50 #include <netinet/in_systm.h>
  51 #include <netinet/ip.h>
  52 #include <netinet/ip_var.h>
  53 #include <netinet/in_var.h>
  54 #include <netinet/ip_ecn.h>
  55 #ifdef INET6
  56 #include <netinet6/ip6_ecn.h>
  57 #endif
  58
  59 #include <netinet/ip6.h>
  60 #ifdef INET6
  61 #include <netinet6/ip6_var.h>
  62 #endif
  63 #include <netinet/in_pcb.h>
  64 #ifdef INET6
  65 #include <netinet/icmp6.h>
  66 #endif
  67
  68 #include <netipsec/ipsec.h>
  69 #ifdef INET6
  70 #include <netipsec/ipsec6.h>
  71 #endif
  72 #include <netipsec/ah_var.h>
  73 #include <netipsec/esp_var.h>
  74 #include <netipsec/ipcomp_var.h>
  75
  76 #include <netipsec/xform.h>
  77
  78 #include <netipsec/key.h>
  79 #include <netipsec/keydb.h>
  80 #include <netipsec/key_debug.h>
  81
  82 #include <machine/in_cksum.h>
  83
  84 int
  85 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
  86 {
  87         struct tdb_ident *tdbi;
  88         struct m_tag *mtag;
  89         struct secasvar *sav;
  90         struct secasindex *saidx;
  91         int error;
  92
  93         IPSEC_SPLASSERT_SOFTNET(__func__);
  94
  95         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  96         IPSEC_ASSERT(isr != NULL, ("null ISR"));
  97         sav = isr->sav;
  98         IPSEC_ASSERT(sav != NULL, ("null SA"));
  99         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
 100
 101         saidx = &sav->sah->saidx;
 102         switch (saidx->dst.sa.sa_family) {
 103 #ifdef INET
 104         case AF_INET:
 105                 /* Fix the header length, for AH processing. */
 106                 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
 107                 break;
 108 #endif /* INET */
 109 #ifdef INET6
 110         case AF_INET6:
 111                 /* Fix the header length, for AH processing. */
 112                 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
 113                         error = ENXIO;
 114                         goto bad;
 115                 }
 116                 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
 117                         /* No jumbogram support. */
 118                         error = ENXIO;  /*?*/
 119                         goto bad;
 120                 }
 121                 mtod(m, struct ip6_hdr *)->ip6_plen =
 122                         htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 123                 break;
 124 #endif /* INET6 */
 125         default:
 126                 DPRINTF(("%s: unknown protocol family %u\n", __func__,
 127                     saidx->dst.sa.sa_family));
 128                 error = ENXIO;
 129                 goto bad;
 130         }
 131
 132         /*
 133          * Add a record of what we've done or what needs to be done to the
 134          * packet.
 135          */
 136         mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
 137                         sizeof(struct tdb_ident), M_NOWAIT);
 138         if (mtag == NULL) {
 139                 DPRINTF(("%s: could not get packet tag\n", __func__));
 140                 error = ENOMEM;
 141                 goto bad;
 142         }
 143
 144         tdbi = (struct tdb_ident *)(mtag + 1);
 145         tdbi->dst = saidx->dst;
 146         tdbi->proto = saidx->proto;
 147         tdbi->spi = sav->spi;
 148         m_tag_prepend(m, mtag);
 149
 150         /*
 151          * If there's another (bundled) SA to apply, do so.
 152          * Note that this puts a burden on the kernel stack size.
 153          * If this is a problem we'll need to introduce a queue
 154          * to set the packet on so we can unwind the stack before
 155          * doing further processing.
 156          */
 157         if (isr->next) {
 158                 newipsecstat.ips_out_bundlesa++;
 159                 return ipsec4_process_packet(m, isr->next, 0, 0);
 160         }
 161         key_sa_recordxfer(sav, m);              /* record data transfer */
 162
 163         /*
 164          * We're done with IPsec processing, transmit the packet using the
 165          * appropriate network protocol (IP or IPv6). SPD lookup will be
 166          * performed again there.
 167          */
 168         switch (saidx->dst.sa.sa_family) {
 169 #ifdef INET
 170         struct ip *ip;
 171         case AF_INET:
 172                 ip = mtod(m, struct ip *);
 173                 ip->ip_len = ntohs(ip->ip_len);
 174                 ip->ip_off = ntohs(ip->ip_off);
 175
 176                 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
 177 #endif /* INET */
 178 #ifdef INET6
 179         case AF_INET6:
 180                 /*
 181                  * We don't need massage, IPv6 header fields are always in
 182                  * net endian.
 183                  */
 184                 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
 185 #endif /* INET6 */
 186         }
 187         panic("ipsec_process_done");
 188 bad:
 189         m_freem(m);
 190         KEY_FREESAV(&sav);
 191         return (error);
 192 }
 193
 194 static struct ipsecrequest *
 195 ipsec_nextisr(
 196         struct mbuf *m,
 197         struct ipsecrequest *isr,
 198         int af,
 199         struct secasindex *saidx,
 200         int *error
 201 )
 202 {
 203 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
 204                             isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
 205         struct secasvar *sav;
 206
 207         IPSEC_SPLASSERT_SOFTNET(__func__);
 208         IPSECREQUEST_LOCK_ASSERT(isr);
 209
 210         IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
 211                 ("invalid address family %u", af));
 212 again:
 213         /*
 214          * Craft SA index to search for proper SA.  Note that
 215          * we only fillin unspecified SA peers for transport
 216          * mode; for tunnel mode they must already be filled in.
 217          */
 218         *saidx = isr->saidx;
 219         if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
 220                 /* Fillin unspecified SA peers only for transport mode */
 221                 if (af == AF_INET) {
 222                         struct sockaddr_in *sin;
 223                         struct ip *ip = mtod(m, struct ip *);
 224
 225                         if (saidx->src.sa.sa_len == 0) {
 226                                 sin = &saidx->src.sin;
 227                                 sin->sin_len = sizeof(*sin);
 228                                 sin->sin_family = AF_INET;
 229                                 sin->sin_port = IPSEC_PORT_ANY;
 230                                 sin->sin_addr = ip->ip_src;
 231                         }
 232                         if (saidx->dst.sa.sa_len == 0) {
 233                                 sin = &saidx->dst.sin;
 234                                 sin->sin_len = sizeof(*sin);
 235                                 sin->sin_family = AF_INET;
 236                                 sin->sin_port = IPSEC_PORT_ANY;
 237                                 sin->sin_addr = ip->ip_dst;
 238                         }
 239                 } else {
 240                         struct sockaddr_in6 *sin6;
 241                         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 242
 243                         if (saidx->src.sin6.sin6_len == 0) {
 244                                 sin6 = (struct sockaddr_in6 *)&saidx->src;
 245                                 sin6->sin6_len = sizeof(*sin6);
 246                                 sin6->sin6_family = AF_INET6;
 247                                 sin6->sin6_port = IPSEC_PORT_ANY;
 248                                 sin6->sin6_addr = ip6->ip6_src;
 249                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
 250                                         /* fix scope id for comparing SPD */
 251                                         sin6->sin6_addr.s6_addr16[1] = 0;
 252                                         sin6->sin6_scope_id =
 253                                             ntohs(ip6->ip6_src.s6_addr16[1]);
 254                                 }
 255                         }
 256                         if (saidx->dst.sin6.sin6_len == 0) {
 257                                 sin6 = (struct sockaddr_in6 *)&saidx->dst;
 258                                 sin6->sin6_len = sizeof(*sin6);
 259                                 sin6->sin6_family = AF_INET6;
 260                                 sin6->sin6_port = IPSEC_PORT_ANY;
 261                                 sin6->sin6_addr = ip6->ip6_dst;
 262                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
 263                                         /* fix scope id for comparing SPD */
 264                                         sin6->sin6_addr.s6_addr16[1] = 0;
 265                                         sin6->sin6_scope_id =
 266                                             ntohs(ip6->ip6_dst.s6_addr16[1]);
 267                                 }
 268                         }
 269                 }
 270         }
 271
 272         /*
 273          * Lookup SA and validate it.
 274          */
 275         *error = key_checkrequest(isr, saidx);
 276         if (*error != 0) {
 277                 /*
 278                  * IPsec processing is required, but no SA found.
 279                  * I assume that key_acquire() had been called
 280                  * to get/establish the SA. Here I discard
 281                  * this packet because it is responsibility for
 282                  * upper layer to retransmit the packet.
 283                  */
 284                 newipsecstat.ips_out_nosa++;
 285                 goto bad;
 286         }
 287         sav = isr->sav;
 288         if (sav == NULL) {              /* XXX valid return */
 289                 IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
 290                         ("no SA found, but required; level %u",
 291                         ipsec_get_reqlevel(isr)));
 292                 IPSECREQUEST_UNLOCK(isr);
 293                 isr = isr->next;
 294                 if (isr == NULL) {
 295                         /*XXXstatistic??*/
 296                         *error = EINVAL;                /*XXX*/
 297                         return isr;
 298                 }
 299                 IPSECREQUEST_LOCK(isr);
 300                 goto again;
 301         }
 302
 303         /*
 304          * Check system global policy controls.
 305          */
 306         if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
 307             (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
 308             (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
 309                 DPRINTF(("%s: IPsec outbound packet dropped due"
 310                         " to policy (check your sysctls)\n", __func__));
 311                 IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
 312                     ipcompstat.ipcomps_pdrops);
 313                 *error = EHOSTUNREACH;
 314                 goto bad;
 315         }
 316
 317         /*
 318          * Sanity check the SA contents for the caller
 319          * before they invoke the xform output method.
 320          */
 321         if (sav->tdb_xform == NULL) {
 322                 DPRINTF(("%s: no transform for SA\n", __func__));
 323                 IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
 324                     ipcompstat.ipcomps_noxform);
 325                 *error = EHOSTUNREACH;
 326                 goto bad;
 327         }
 328         return isr;
 329 bad:
 330         IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
 331         IPSECREQUEST_UNLOCK(isr);
 332         return NULL;
 333 #undef IPSEC_OSTAT
 334 }
 335
 336 #ifdef INET
 337 /*
 338  * IPsec output logic for IPv4.
 339  */
 340 int
 341 ipsec4_process_packet(
 342         struct mbuf *m,
 343         struct ipsecrequest *isr,
 344         int flags,
 345         int tunalready)
 346 {
 347         struct secasindex saidx;
 348         struct secasvar *sav;
 349         struct ip *ip;
 350         int error, i, off;
 351
 352         IPSEC_ASSERT(m != NULL, ("null mbuf"));
 353         IPSEC_ASSERT(isr != NULL, ("null isr"));
 354
 355         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
 356
 357         isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
 358         if (isr == NULL)
 359                 goto bad;
 360
 361         sav = isr->sav;
 362
 363 #ifdef DEV_ENC
 364         /* pass the mbuf to enc0 for packet filtering */
 365         if ((error = ipsec_filter(&m, 2)) != 0)
 366                 goto bad;
 367 #endif
 368
 369         if (!tunalready) {
 370                 union sockaddr_union *dst = &sav->sah->saidx.dst;
 371                 int setdf;
 372
 373                 /*
 374                  * Collect IP_DF state from the outer header.
 375                  */
 376                 if (dst->sa.sa_family == AF_INET) {
 377                         if (m->m_len < sizeof (struct ip) &&
 378                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
 379                                 error = ENOBUFS;
 380                                 goto bad;
 381                         }
 382                         ip = mtod(m, struct ip *);
 383                         /* Honor system-wide control of how to handle IP_DF */
 384                         switch (ip4_ipsec_dfbit) {
 385                         case 0:                 /* clear in outer header */
 386                         case 1:                 /* set in outer header */
 387                                 setdf = ip4_ipsec_dfbit;
 388                                 break;
 389                         default:                /* propagate to outer header */
 390                                 setdf = ntohs(ip->ip_off & IP_DF);
 391                                 break;
 392                         }
 393                 } else {
 394                         ip = NULL;              /* keep compiler happy */
 395                         setdf = 0;
 396                 }
 397                 /* Do the appropriate encapsulation, if necessary */
 398                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
 399                     dst->sa.sa_family != AF_INET ||         /* PF mismatch */
 400 #if 0
 401                     (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
 402                     sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
 403 #endif
 404                     (dst->sa.sa_family == AF_INET &&        /* Proxy */
 405                      dst->sin.sin_addr.s_addr != INADDR_ANY &&
 406                      dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
 407                         struct mbuf *mp;
 408
 409                         /* Fix IPv4 header checksum and length */
 410                         if (m->m_len < sizeof (struct ip) &&
 411                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
 412                                 error = ENOBUFS;
 413                                 goto bad;
 414                         }
 415                         ip = mtod(m, struct ip *);
 416                         ip->ip_len = htons(m->m_pkthdr.len);
 417                         ip->ip_sum = 0;
 418 #ifdef _IP_VHL
 419                         if (ip->ip_vhl == IP_VHL_BORING)
 420                                 ip->ip_sum = in_cksum_hdr(ip);
 421                         else
 422                                 ip->ip_sum = in_cksum(m,
 423                                         _IP_VHL_HL(ip->ip_vhl) << 2);
 424 #else
 425                         ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
 426 #endif
 427
 428                         /* Encapsulate the packet */
 429                         error = ipip_output(m, isr, &mp, 0, 0);
 430                         if (mp == NULL && !error) {
 431                                 /* Should never happen. */
 432                                 DPRINTF(("%s: ipip_output returns no mbuf and "
 433                                         "no error!", __func__));
 434                                 error = EFAULT;
 435                         }
 436                         if (error) {
 437                                 if (mp) {
 438                                         /* XXX: Should never happen! */
 439                                         m_freem(mp);
 440                                 }
 441                                 m = NULL; /* ipip_output() already freed it */
 442                                 goto bad;
 443                         }
 444                         m = mp, mp = NULL;
 445                         /*
 446                          * ipip_output clears IP_DF in the new header.  If
 447                          * we need to propagate IP_DF from the outer header,
 448                          * then we have to do it here.
 449                          *
 450                          * XXX shouldn't assume what ipip_output does.
 451                          */
 452                         if (dst->sa.sa_family == AF_INET && setdf) {
 453                                 if (m->m_len < sizeof (struct ip) &&
 454                                     (m = m_pullup(m, sizeof (struct ip))) == NULL) {
 455                                         error = ENOBUFS;
 456                                         goto bad;
 457                                 }
 458                                 ip = mtod(m, struct ip *);
 459                                 ip->ip_off = ntohs(ip->ip_off);
 460                                 ip->ip_off |= IP_DF;
 461                                 ip->ip_off = htons(ip->ip_off);
 462                         }
 463                 }
 464         }
 465
 466 #ifdef DEV_ENC
 467         /* pass the mbuf to enc0 for bpf processing */
 468         ipsec_bpf(m, sav, AF_INET);
 469 #endif
 470
 471         /*
 472          * Dispatch to the appropriate IPsec transform logic.  The
 473          * packet will be returned for transmission after crypto
 474          * processing, etc. are completed.  For encapsulation we
 475          * bypass this call because of the explicit call done above
 476          * (necessary to deal with IP_DF handling for IPv4).
 477          *
 478          * NB: m & sav are ``passed to caller'' who's reponsible for
 479          *     for reclaiming their resources.
 480          */
 481         if (sav->tdb_xform->xf_type != XF_IP4) {
 482                 ip = mtod(m, struct ip *);
 483                 i = ip->ip_hl << 2;
 484                 off = offsetof(struct ip, ip_p);
 485                 error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
 486         } else {
 487                 error = ipsec_process_done(m, isr);
 488         }
 489         IPSECREQUEST_UNLOCK(isr);
 490         return error;
 491 bad:
 492         if (isr)
 493                 IPSECREQUEST_UNLOCK(isr);
 494         if (m)
 495                 m_freem(m);
 496         return error;
 497 }
 498 #endif
 499
 500 #ifdef INET6
 501 /*
 502  * Chop IP6 header from the payload.
 503  */
 504 static struct mbuf *
 505 ipsec6_splithdr(struct mbuf *m)
 506 {
 507         struct mbuf *mh;
 508         struct ip6_hdr *ip6;
 509         int hlen;
 510
 511         IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
 512                 ("first mbuf too short, len %u", m->m_len));
 513         ip6 = mtod(m, struct ip6_hdr *);
 514         hlen = sizeof(struct ip6_hdr);
 515         if (m->m_len > hlen) {
 516                 MGETHDR(mh, M_DONTWAIT, MT_HEADER);
 517                 if (!mh) {
 518                         m_freem(m);
 519                         return NULL;
 520                 }
 521                 M_MOVE_PKTHDR(mh, m);
 522                 MH_ALIGN(mh, hlen);
 523                 m->m_len -= hlen;
 524                 m->m_data += hlen;
 525                 mh->m_next = m;
 526                 m = mh;
 527                 m->m_len = hlen;
 528                 bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
 529         } else if (m->m_len < hlen) {
 530                 m = m_pullup(m, hlen);
 531                 if (!m)
 532                         return NULL;
 533         }
 534         return m;
 535 }
 536
 537 /*
 538  * IPsec output logic for IPv6, transport mode.
 539  */
 540 int
 541 ipsec6_output_trans(
 542         struct ipsec_output_state *state,
 543         u_char *nexthdrp,
 544         struct mbuf *mprev,
 545         struct secpolicy *sp,
 546         int flags,
 547         int *tun)
 548 {
 549         struct ipsecrequest *isr;
 550         struct secasindex saidx;
 551         int error = 0;
 552         struct mbuf *m;
 553
 554         IPSEC_ASSERT(state != NULL, ("null state"));
 555         IPSEC_ASSERT(state->m != NULL, ("null m"));
 556         IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
 557         IPSEC_ASSERT(mprev != NULL, ("null mprev"));
 558         IPSEC_ASSERT(sp != NULL, ("null sp"));
 559         IPSEC_ASSERT(tun != NULL, ("null tun"));
 560
 561         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
 562                 printf("%s: applyed SP\n", __func__);
 563                 kdebug_secpolicy(sp));
 564
 565         isr = sp->req;
 566         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
 567                 /* the rest will be handled by ipsec6_output_tunnel() */
 568                 *tun = 1;               /* need tunnel-mode processing */
 569                 return 0;
 570         }
 571
 572         *tun = 0;
 573         m = state->m;
 574
 575         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
 576         if (isr == NULL) {
 577 #ifdef notdef
 578                 /* XXX should notification be done for all errors ? */
 579                 /*
 580                  * Notify the fact that the packet is discarded
 581                  * to ourselves. I believe this is better than
 582                  * just silently discarding. (jinmei@kame.net)
 583                  * XXX: should we restrict the error to TCP packets?
 584                  * XXX: should we directly notify sockets via
 585                  *      pfctlinputs?
 586                  */
 587                 icmp6_error(m, ICMP6_DST_UNREACH,
 588                             ICMP6_DST_UNREACH_ADMIN, 0);
 589                 m = NULL;       /* NB: icmp6_error frees mbuf */
 590 #endif
 591                 goto bad;
 592         }
 593
 594         return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
 595                 sizeof (struct ip6_hdr),
 596                 offsetof(struct ip6_hdr, ip6_nxt));
 597 bad:
 598         if (m)
 599                 m_freem(m);
 600         state->m = NULL;
 601         return error;
 602 }
 603
 604 static int
 605 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
 606 {
 607         struct ip6_hdr *oip6;
 608         struct ip6_hdr *ip6;
 609         size_t plen;
 610
 611         /* can't tunnel between different AFs */
 612         if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
 613             sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
 614                 m_freem(m);
 615                 return EINVAL;
 616         }
 617         IPSEC_ASSERT(m->m_len != sizeof (struct ip6_hdr),
 618                 ("mbuf wrong size; len %u", m->m_len));
 619
 620
 621         /*
 622          * grow the mbuf to accomodate the new IPv6 header.
 623          */
 624         plen = m->m_pkthdr.len;
 625         if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
 626                 struct mbuf *n;
 627                 MGET(n, M_DONTWAIT, MT_DATA);
 628                 if (!n) {
 629                         m_freem(m);
 630                         return ENOBUFS;
 631                 }
 632                 n->m_len = sizeof(struct ip6_hdr);
 633                 n->m_next = m->m_next;
 634                 m->m_next = n;
 635                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
 636                 oip6 = mtod(n, struct ip6_hdr *);
 637         } else {
 638                 m->m_next->m_len += sizeof(struct ip6_hdr);
 639                 m->m_next->m_data -= sizeof(struct ip6_hdr);
 640                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
 641                 oip6 = mtod(m->m_next, struct ip6_hdr *);
 642         }
 643         ip6 = mtod(m, struct ip6_hdr *);
 644         bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
 645
 646         /* Fake link-local scope-class addresses */
 647         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
 648                 oip6->ip6_src.s6_addr16[1] = 0;
 649         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
 650                 oip6->ip6_dst.s6_addr16[1] = 0;
 651
 652         /* construct new IPv6 header. see RFC 2401 5.1.2.2 */
 653         /* ECN consideration. */
 654         ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
 655         if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
 656                 ip6->ip6_plen = htons(plen);
 657         else {
 658                 /* ip6->ip6_plen will be updated in ip6_output() */
 659         }
 660         ip6->ip6_nxt = IPPROTO_IPV6;
 661         sav->sah->saidx.src.sin6.sin6_addr = ip6->ip6_src;
 662         sav->sah->saidx.dst.sin6.sin6_addr = ip6->ip6_dst;
 663         ip6->ip6_hlim = IPV6_DEFHLIM;
 664
 665         /* XXX Should ip6_src be updated later ? */
 666
 667         return 0;
 668 }
 669
 670 /*
 671  * IPsec output logic for IPv6, tunnel mode.
 672  */
 673 int
 674 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
 675 {
 676         struct ip6_hdr *ip6;
 677         struct ipsecrequest *isr;
 678         struct secasindex saidx;
 679         int error;
 680         struct sockaddr_in6* dst6;
 681         struct mbuf *m;
 682
 683         IPSEC_ASSERT(state != NULL, ("null state"));
 684         IPSEC_ASSERT(state->m != NULL, ("null m"));
 685         IPSEC_ASSERT(sp != NULL, ("null sp"));
 686
 687         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
 688                 printf("%s: applyed SP\n", __func__);
 689                 kdebug_secpolicy(sp));
 690
 691         m = state->m;
 692         /*
 693          * transport mode ipsec (before the 1st tunnel mode) is already
 694          * processed by ipsec6_output_trans().
 695          */
 696         for (isr = sp->req; isr; isr = isr->next) {
 697                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
 698                         break;
 699         }
 700         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
 701         if (isr == NULL)
 702                 goto bad;
 703
 704         /*
 705          * There may be the case that SA status will be changed when
 706          * we are refering to one. So calling splsoftnet().
 707          */
 708         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
 709                 /*
 710                  * build IPsec tunnel.
 711                  */
 712                 /* XXX should be processed with other familiy */
 713                 if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
 714                         ipseclog((LOG_ERR, "%s: family mismatched between "
 715                             "inner and outer, spi=%u\n", __func__,
 716                             ntohl(isr->sav->spi)));
 717                         newipsecstat.ips_out_inval++;
 718                         error = EAFNOSUPPORT;
 719                         goto bad;
 720                 }
 721
 722                 m = ipsec6_splithdr(m);
 723                 if (!m) {
 724                         newipsecstat.ips_out_nomem++;
 725                         error = ENOMEM;
 726                         goto bad;
 727                 }
 728                 error = ipsec6_encapsulate(m, isr->sav);
 729                 if (error) {
 730                         m = NULL;
 731                         goto bad;
 732                 }
 733                 ip6 = mtod(m, struct ip6_hdr *);
 734
 735                 state->ro = &isr->sav->sah->sa_route;
 736                 state->dst = (struct sockaddr *)&state->ro->ro_dst;
 737                 dst6 = (struct sockaddr_in6 *)state->dst;
 738                 if (state->ro->ro_rt
 739                  && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
 740                   || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
 741                         RTFREE(state->ro->ro_rt);
 742                         state->ro->ro_rt = NULL;
 743                 }
 744                 if (state->ro->ro_rt == 0) {
 745                         bzero(dst6, sizeof(*dst6));
 746                         dst6->sin6_family = AF_INET6;
 747                         dst6->sin6_len = sizeof(*dst6);
 748                         dst6->sin6_addr = ip6->ip6_dst;
 749                         rtalloc(state->ro);
 750                 }
 751                 if (state->ro->ro_rt == 0) {
 752                         ip6stat.ip6s_noroute++;
 753                         newipsecstat.ips_out_noroute++;
 754                         error = EHOSTUNREACH;
 755                         goto bad;
 756                 }
 757
 758                 /* adjust state->dst if tunnel endpoint is offlink */
 759                 if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) {
 760                         state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
 761                         dst6 = (struct sockaddr_in6 *)state->dst;
 762                 }
 763         }
 764
 765         m = ipsec6_splithdr(m);
 766         if (!m) {
 767                 newipsecstat.ips_out_nomem++;
 768                 error = ENOMEM;
 769                 goto bad;
 770         }
 771         ip6 = mtod(m, struct ip6_hdr *);
 772         return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
 773                 sizeof (struct ip6_hdr),
 774                 offsetof(struct ip6_hdr, ip6_nxt));
 775 bad:
 776         if (m)
 777                 m_freem(m);
 778         state->m = NULL;
 779         return error;
 780 }
 781 #endif /*INET6*/