The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netipsec/ipsec_output.c

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    1 /*      $NetBSD: ipsec_output.c,v 1.13.12.1 2007/11/22 19:00:53 bouyer Exp $    */
    2 
    3 /*-
    4  * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  *
   28  * $FreeBSD: /repoman/r/ncvs/src/sys/netipsec/ipsec_output.c,v 1.3.2.2 2003/03/28 20:32:53 sam Exp $
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __KERNEL_RCSID(0, "$NetBSD: ipsec_output.c,v 1.13.12.1 2007/11/22 19:00:53 bouyer Exp $");
   33 
   34 /*
   35  * IPsec output processing.
   36  */
   37 #include "opt_inet.h"
   38 #ifdef __FreeBSD__
   39 #include "opt_inet6.h"
   40 #endif
   41 #include "opt_ipsec.h"
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/mbuf.h>
   46 #include <sys/domain.h>
   47 #include <sys/protosw.h>
   48 #include <sys/socket.h>
   49 #include <sys/errno.h>
   50 #include <sys/syslog.h>
   51 
   52 #include <net/if.h>
   53 #include <net/route.h>
   54 
   55 #include <netinet/in.h>
   56 #include <netinet/in_systm.h>
   57 #include <netinet/ip.h>
   58 #include <netinet/ip_var.h>
   59 #include <netinet/in_var.h>
   60 #include <netinet/ip_ecn.h>
   61 #ifdef INET6
   62 #  ifdef __FreeBSD__
   63 #  include <netinet6/ip6_ecn.h>
   64 #  endif
   65 #endif
   66 
   67 #include <netinet/ip6.h>
   68 #ifdef INET6
   69 #include <netinet6/ip6_var.h>
   70 #endif
   71 #include <netinet/in_pcb.h>
   72 #ifdef INET6
   73 #include <netinet/icmp6.h>
   74 #endif
   75 
   76 #include <netipsec/ipsec.h>
   77 #include <netipsec/ipsec_var.h>
   78 #ifdef INET6
   79 #include <netipsec/ipsec6.h>
   80 #endif
   81 #include <netipsec/ah_var.h>
   82 #include <netipsec/esp_var.h>
   83 #include <netipsec/ipcomp_var.h>
   84 
   85 #include <netipsec/xform.h>
   86 
   87 #include <netipsec/key.h>
   88 #include <netipsec/keydb.h>
   89 #include <netipsec/key_debug.h>
   90 #include <netipsec/ipsec_osdep.h>
   91 
   92 #include <net/net_osdep.h>              /* ovbcopy() in ipsec6_encapsulate() */
   93 
   94 int
   95 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
   96 {
   97         struct tdb_ident *tdbi;
   98         struct m_tag *mtag;
   99         struct secasvar *sav;
  100         struct secasindex *saidx;
  101         int error;
  102 
  103         IPSEC_SPLASSERT_SOFTNET("ipsec_process_done");
  104 
  105         IPSEC_ASSERT(m != NULL, ("ipsec_process_done: null mbuf"));
  106         IPSEC_ASSERT(isr != NULL, ("ipsec_process_done: null ISR"));
  107         sav = isr->sav;
  108         IPSEC_ASSERT(sav != NULL, ("ipsec_process_done: null SA"));
  109         IPSEC_ASSERT(sav->sah != NULL, ("ipsec_process_done: null SAH"));
  110 
  111         saidx = &sav->sah->saidx;
  112         switch (saidx->dst.sa.sa_family) {
  113 #ifdef INET
  114         case AF_INET:
  115                 /* Fix the header length, for AH processing. */
  116                 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
  117                 break;
  118 #endif /* INET */
  119 #ifdef INET6
  120         case AF_INET6:
  121                 /* Fix the header length, for AH processing. */
  122                 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
  123                         error = ENXIO;
  124                         goto bad;
  125                 }
  126                 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
  127                         /* No jumbogram support. */
  128                         error = ENXIO;  /*?*/
  129                         goto bad;
  130                 }
  131                 mtod(m, struct ip6_hdr *)->ip6_plen =
  132                         htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  133                 break;
  134 #endif /* INET6 */
  135         default:
  136                 DPRINTF(("ipsec_process_done: unknown protocol family %u\n",
  137                     saidx->dst.sa.sa_family));
  138                 error = ENXIO;
  139                 goto bad;
  140         }
  141 
  142         /*
  143          * Add a record of what we've done or what needs to be done to the
  144          * packet.
  145          */
  146         mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
  147                         sizeof(struct tdb_ident), M_NOWAIT);
  148         if (mtag == NULL) {
  149                 DPRINTF(("ipsec_process_done: could not get packet tag\n"));
  150                 error = ENOMEM;
  151                 goto bad;
  152         }
  153 
  154         tdbi = (struct tdb_ident *)(mtag + 1);
  155         tdbi->dst = saidx->dst;
  156         tdbi->proto = saidx->proto;
  157         tdbi->spi = sav->spi;
  158         m_tag_prepend(m, mtag);
  159 
  160         /*
  161          * If there's another (bundled) SA to apply, do so.
  162          * Note that this puts a burden on the kernel stack size.
  163          * If this is a problem we'll need to introduce a queue
  164          * to set the packet on so we can unwind the stack before
  165          * doing further processing.
  166          */
  167         if (isr->next) {
  168                 newipsecstat.ips_out_bundlesa++;
  169                 return ipsec4_process_packet(m, isr->next, 0, 0);
  170         }
  171 
  172         /*
  173          * We're done with IPsec processing, transmit the packet using the
  174          * appropriate network protocol (IP or IPv6). SPD lookup will be
  175          * performed again there.
  176          */
  177         switch (saidx->dst.sa.sa_family) {
  178 #ifdef INET
  179         struct ip *ip;
  180         case AF_INET:
  181                 ip = mtod(m, struct ip *);
  182 #ifdef __FreeBSD__
  183                 /* FreeBSD ip_output() expects ip_len, ip_off in host endian */
  184                 ip->ip_len = ntohs(ip->ip_len);
  185                 ip->ip_off = ntohs(ip->ip_off);
  186 #endif /* __FreeBSD_ */
  187                 return ip_output(m, NULL, NULL, IP_RAWOUTPUT,
  188                     (struct ip_moptions *)NULL, (struct socket *)NULL);
  189 
  190 #endif /* INET */
  191 #ifdef INET6
  192         case AF_INET6:
  193                 /*
  194                  * We don't need massage, IPv6 header fields are always in
  195                  * net endian.
  196                  */
  197                 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
  198 #endif /* INET6 */
  199         }
  200         panic("ipsec_process_done");
  201 bad:
  202         m_freem(m);
  203         KEY_FREESAV(&sav);
  204         return (error);
  205 }
  206 
  207 static struct ipsecrequest *
  208 ipsec_nextisr(
  209         struct mbuf *m,
  210         struct ipsecrequest *isr,
  211         int af,
  212         struct secasindex *saidx,
  213         int *error
  214 )
  215 {
  216 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
  217                             isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
  218         struct secasvar *sav;
  219 
  220         IPSEC_SPLASSERT_SOFTNET("ipsec_nextisr");
  221         IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
  222                 ("ipsec_nextisr: invalid address family %u", af));
  223 again:
  224         /*
  225          * Craft SA index to search for proper SA.  Note that
  226          * we only fillin unspecified SA peers for transport
  227          * mode; for tunnel mode they must already be filled in.
  228          */
  229         *saidx = isr->saidx;
  230         if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
  231                 /* Fillin unspecified SA peers only for transport mode */
  232                 if (af == AF_INET) {
  233                         struct sockaddr_in *sin;
  234                         struct ip *ip = mtod(m, struct ip *);
  235 
  236                         if (saidx->src.sa.sa_len == 0) {
  237                                 sin = &saidx->src.sin;
  238                                 sin->sin_len = sizeof(*sin);
  239                                 sin->sin_family = AF_INET;
  240                                 sin->sin_port = IPSEC_PORT_ANY;
  241                                 sin->sin_addr = ip->ip_src;
  242                         }
  243                         if (saidx->dst.sa.sa_len == 0) {
  244                                 sin = &saidx->dst.sin;
  245                                 sin->sin_len = sizeof(*sin);
  246                                 sin->sin_family = AF_INET;
  247                                 sin->sin_port = IPSEC_PORT_ANY;
  248                                 sin->sin_addr = ip->ip_dst;
  249                         }
  250                 } else {
  251                         struct sockaddr_in6 *sin6;
  252                         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  253 
  254                         if (saidx->src.sin6.sin6_len == 0) {
  255                                 sin6 = (struct sockaddr_in6 *)&saidx->src;
  256                                 sin6->sin6_len = sizeof(*sin6);
  257                                 sin6->sin6_family = AF_INET6;
  258                                 sin6->sin6_port = IPSEC_PORT_ANY;
  259                                 sin6->sin6_addr = ip6->ip6_src;
  260                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
  261                                         /* fix scope id for comparing SPD */
  262                                         sin6->sin6_addr.s6_addr16[1] = 0;
  263                                         sin6->sin6_scope_id =
  264                                             ntohs(ip6->ip6_src.s6_addr16[1]);
  265                                 }
  266                         }
  267                         if (saidx->dst.sin6.sin6_len == 0) {
  268                                 sin6 = (struct sockaddr_in6 *)&saidx->dst;
  269                                 sin6->sin6_len = sizeof(*sin6);
  270                                 sin6->sin6_family = AF_INET6;
  271                                 sin6->sin6_port = IPSEC_PORT_ANY;
  272                                 sin6->sin6_addr = ip6->ip6_dst;
  273                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
  274                                         /* fix scope id for comparing SPD */
  275                                         sin6->sin6_addr.s6_addr16[1] = 0;
  276                                         sin6->sin6_scope_id =
  277                                             ntohs(ip6->ip6_dst.s6_addr16[1]);
  278                                 }
  279                         }
  280                 }
  281         }
  282 
  283         /*
  284          * Lookup SA and validate it.
  285          */
  286         *error = key_checkrequest(isr, saidx);
  287         if (*error != 0) {
  288                 /*
  289                  * IPsec processing is required, but no SA found.
  290                  * I assume that key_acquire() had been called
  291                  * to get/establish the SA. Here I discard
  292                  * this packet because it is responsibility for
  293                  * upper layer to retransmit the packet.
  294                  */
  295                 newipsecstat.ips_out_nosa++;
  296                 goto bad;
  297         }
  298         sav = isr->sav;
  299         if (sav == NULL) {              /* XXX valid return */
  300                 IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
  301                         ("ipsec_nextisr: no SA found, but required; level %u",
  302                         ipsec_get_reqlevel(isr)));
  303                 isr = isr->next;
  304                 if (isr == NULL) {
  305                         /*XXXstatistic??*/
  306                         *error = EINVAL;                /*XXX*/
  307                         return isr;
  308                 }
  309                 goto again;
  310         }
  311 
  312         /*
  313          * Check system global policy controls.
  314          */
  315         if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
  316             (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
  317             (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
  318                 DPRINTF(("ipsec_nextisr: IPsec outbound packet dropped due"
  319                         " to policy (check your sysctls)\n"));
  320                 IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
  321                     ipcompstat.ipcomps_pdrops);
  322                 *error = EHOSTUNREACH;
  323                 goto bad;
  324         }
  325 
  326         /*
  327          * Sanity check the SA contents for the caller
  328          * before they invoke the xform output method.
  329          */
  330         if (sav->tdb_xform == NULL) {
  331                 DPRINTF(("ipsec_nextisr: no transform for SA\n"));
  332                 IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
  333                     ipcompstat.ipcomps_noxform);
  334                 *error = EHOSTUNREACH;
  335                 goto bad;
  336         }
  337         return isr;
  338 bad:
  339         IPSEC_ASSERT(*error != 0, ("ipsec_nextisr: error return w/ no error code"));
  340         return NULL;
  341 #undef IPSEC_OSTAT
  342 }
  343 
  344 #ifdef INET
  345 /*
  346  * IPsec output logic for IPv4.
  347  */
  348 int
  349 ipsec4_process_packet(
  350         struct mbuf *m,
  351         struct ipsecrequest *isr,
  352         int flags,
  353         int tunalready)
  354 {
  355         struct secasindex saidx;
  356         struct secasvar *sav;
  357         struct ip *ip;
  358         int s, error, i, off;
  359 
  360         IPSEC_ASSERT(m != NULL, ("ipsec4_process_packet: null mbuf"));
  361         IPSEC_ASSERT(isr != NULL, ("ipsec4_process_packet: null isr"));
  362 
  363         s = splsoftnet();                       /* insure SA contents don't change */
  364 
  365         isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
  366         if (isr == NULL)
  367                 goto bad;
  368 
  369         sav = isr->sav;
  370         if (!tunalready) {
  371                 union sockaddr_union *dst = &sav->sah->saidx.dst;
  372                 int setdf;
  373 
  374                 /*
  375                  * Collect IP_DF state from the outer header.
  376                  */
  377                 if (dst->sa.sa_family == AF_INET) {
  378                         if (m->m_len < sizeof (struct ip) &&
  379                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  380                                 error = ENOBUFS;
  381                                 goto bad;
  382                         }
  383                         ip = mtod(m, struct ip *);
  384                         /* Honor system-wide control of how to handle IP_DF */
  385                         switch (ip4_ipsec_dfbit) {
  386                         case 0:                 /* clear in outer header */
  387                         case 1:                 /* set in outer header */
  388                                 setdf = ip4_ipsec_dfbit;
  389                                 break;
  390                         default:                /* propagate to outer header */
  391                                 setdf = ip->ip_off;
  392 #ifndef __FreeBSD__
  393                 /* On FreeBSD, ip_off and ip_len assumed in host endian. */
  394                                 setdf = ntohs(setdf);
  395 #endif
  396                                 setdf = htons(setdf & IP_DF);
  397                                 break;
  398                         }
  399                 } else {
  400                         ip = NULL;              /* keep compiler happy */
  401                         setdf = 0;
  402                 }
  403                 /* Do the appropriate encapsulation, if necessary */
  404                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
  405                     dst->sa.sa_family != AF_INET ||         /* PF mismatch */
  406 #if 0
  407                     (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
  408                     sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
  409 #endif
  410                     (dst->sa.sa_family == AF_INET &&        /* Proxy */
  411                      dst->sin.sin_addr.s_addr != INADDR_ANY &&
  412                      dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
  413                         struct mbuf *mp;
  414 
  415                         /* Fix IPv4 header checksum and length */
  416                         if (m->m_len < sizeof (struct ip) &&
  417                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  418                                 error = ENOBUFS;
  419                                 goto bad;
  420                         }
  421                         ip = mtod(m, struct ip *);
  422                         ip->ip_len = htons(m->m_pkthdr.len);
  423                         ip->ip_sum = 0;
  424 #ifdef _IP_VHL
  425                         if (ip->ip_vhl == IP_VHL_BORING)
  426                                 ip->ip_sum = in_cksum_hdr(ip);
  427                         else
  428                                 ip->ip_sum = in_cksum(m,
  429                                         _IP_VHL_HL(ip->ip_vhl) << 2);
  430 #else
  431                         ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  432 #endif
  433 
  434                         /* Encapsulate the packet */
  435                         error = ipip_output(m, isr, &mp, 0, 0);
  436                         if (mp == NULL && !error) {
  437                                 /* Should never happen. */
  438                                 DPRINTF(("ipsec4_process_packet: ipip_output "
  439                                         "returns no mbuf and no error!"));
  440                                 error = EFAULT;
  441                         }
  442                         if (error) {
  443                                 if (mp) {
  444                                         /* XXX: Should never happen! */
  445                                         m_freem(mp);
  446                                 }
  447                                 m = NULL; /* ipip_output() already freed it */
  448                                 goto bad;
  449                         }
  450                         m = mp, mp = NULL;
  451                         /*
  452                          * ipip_output clears IP_DF in the new header.  If
  453                          * we need to propagate IP_DF from the outer header,
  454                          * then we have to do it here.
  455                          *
  456                          * XXX shouldn't assume what ipip_output does.
  457                          */
  458                         if (dst->sa.sa_family == AF_INET && setdf) {
  459                                 if (m->m_len < sizeof (struct ip) &&
  460                                     (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  461                                         error = ENOBUFS;
  462                                         goto bad;
  463                                 }
  464                                 ip = mtod(m, struct ip *);
  465                                 ip->ip_off |= IP_OFF_CONVERT(IP_DF);
  466                         }
  467                 }
  468         }
  469 
  470         /*
  471          * Dispatch to the appropriate IPsec transform logic.  The
  472          * packet will be returned for transmission after crypto
  473          * processing, etc. are completed.  For encapsulation we
  474          * bypass this call because of the explicit call done above
  475          * (necessary to deal with IP_DF handling for IPv4).
  476          *
  477          * NB: m & sav are ``passed to caller'' who's reponsible for
  478          *     for reclaiming their resources.
  479          */
  480         if (sav->tdb_xform->xf_type != XF_IP4) {
  481                 ip = mtod(m, struct ip *);
  482                 i = ip->ip_hl << 2;
  483                 off = offsetof(struct ip, ip_p);
  484                 error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
  485         } else {
  486                 error = ipsec_process_done(m, isr);
  487         }
  488         splx(s);
  489         return error;
  490 bad:
  491         splx(s);
  492         if (m)
  493                 m_freem(m);
  494         return error;
  495 }
  496 #endif
  497 
  498 #ifdef INET6
  499 /*
  500  * Chop IP6 header from the payload.
  501  */
  502 static struct mbuf *
  503 ipsec6_splithdr(struct mbuf *m)
  504 {
  505         struct mbuf *mh;
  506         struct ip6_hdr *ip6;
  507         int hlen;
  508 
  509         IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
  510                 ("ipsec6_splithdr: first mbuf too short, len %u", m->m_len));
  511         ip6 = mtod(m, struct ip6_hdr *);
  512         hlen = sizeof(struct ip6_hdr);
  513         if (m->m_len > hlen) {
  514                 MGETHDR(mh, M_DONTWAIT, MT_HEADER);
  515                 if (!mh) {
  516                         m_freem(m);
  517                         return NULL;
  518                 }
  519                 M_MOVE_PKTHDR(mh, m);
  520                 MH_ALIGN(mh, hlen);
  521                 m->m_len -= hlen;
  522                 m->m_data += hlen;
  523                 mh->m_next = m;
  524                 m = mh;
  525                 m->m_len = hlen;
  526                 bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
  527         } else if (m->m_len < hlen) {
  528                 m = m_pullup(m, hlen);
  529                 if (!m)
  530                         return NULL;
  531         }
  532         return m;
  533 }
  534 
  535 /*
  536  * IPsec output logic for IPv6, transport mode.
  537  */
  538 int
  539 ipsec6_output_trans(
  540         struct ipsec_output_state *state,
  541         u_char *nexthdrp,
  542         struct mbuf *mprev,
  543         struct secpolicy *sp,
  544         int flags,
  545         int *tun)
  546 {
  547         struct ipsecrequest *isr;
  548         struct secasindex saidx;
  549         int error = 0;
  550         struct mbuf *m;
  551 
  552         IPSEC_ASSERT(state != NULL, ("ipsec6_output: null state"));
  553         IPSEC_ASSERT(state->m != NULL, ("ipsec6_output: null m"));
  554         IPSEC_ASSERT(nexthdrp != NULL, ("ipsec6_output: null nexthdrp"));
  555         IPSEC_ASSERT(mprev != NULL, ("ipsec6_output: null mprev"));
  556         IPSEC_ASSERT(sp != NULL, ("ipsec6_output: null sp"));
  557         IPSEC_ASSERT(tun != NULL, ("ipsec6_output: null tun"));
  558 
  559         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  560                 printf("ipsec6_output_trans: applyed SP\n");
  561                 kdebug_secpolicy(sp));
  562 
  563         isr = sp->req;
  564         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  565                 /* the rest will be handled by ipsec6_output_tunnel() */
  566                 *tun = 1;               /* need tunnel-mode processing */
  567                 return 0;
  568         }
  569 
  570         *tun = 0;
  571         m = state->m;
  572 
  573         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  574         if (isr == NULL) {
  575 #ifdef notdef
  576                 /* XXX should notification be done for all errors ? */
  577                 /*
  578                  * Notify the fact that the packet is discarded
  579                  * to ourselves. I believe this is better than
  580                  * just silently discarding. (jinmei@kame.net)
  581                  * XXX: should we restrict the error to TCP packets?
  582                  * XXX: should we directly notify sockets via
  583                  *      pfctlinputs?
  584                  */
  585                 icmp6_error(m, ICMP6_DST_UNREACH,
  586                             ICMP6_DST_UNREACH_ADMIN, 0);
  587                 m = NULL;       /* NB: icmp6_error frees mbuf */
  588 #endif
  589                 goto bad;
  590         }
  591 
  592         return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  593                 sizeof (struct ip6_hdr),
  594                 offsetof(struct ip6_hdr, ip6_nxt));
  595 bad:
  596         if (m)
  597                 m_freem(m);
  598         state->m = NULL;
  599         return error;
  600 }
  601 
  602 static int
  603 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
  604 {
  605         struct ip6_hdr *oip6;
  606         struct ip6_hdr *ip6;
  607         size_t plen;
  608 
  609         /* can't tunnel between different AFs */
  610         if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
  611             sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
  612                 m_freem(m);
  613                 return EINVAL;
  614         }
  615         IPSEC_ASSERT(m->m_len != sizeof (struct ip6_hdr),
  616                 ("ipsec6_encapsulate: mbuf wrong size; len %u", m->m_len));
  617 
  618 
  619         /*
  620          * grow the mbuf to accomodate the new IPv6 header.
  621          */
  622         plen = m->m_pkthdr.len;
  623         if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
  624                 struct mbuf *n;
  625                 MGET(n, M_DONTWAIT, MT_DATA);
  626                 if (!n) {
  627                         m_freem(m);
  628                         return ENOBUFS;
  629                 }
  630                 n->m_len = sizeof(struct ip6_hdr);
  631                 n->m_next = m->m_next;
  632                 m->m_next = n;
  633                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  634                 oip6 = mtod(n, struct ip6_hdr *);
  635         } else {
  636                 m->m_next->m_len += sizeof(struct ip6_hdr);
  637                 m->m_next->m_data -= sizeof(struct ip6_hdr);
  638                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  639                 oip6 = mtod(m->m_next, struct ip6_hdr *);
  640         }
  641         ip6 = mtod(m, struct ip6_hdr *);
  642         ovbcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
  643 
  644         /* Fake link-local scope-class addresses */
  645         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
  646                 oip6->ip6_src.s6_addr16[1] = 0;
  647         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
  648                 oip6->ip6_dst.s6_addr16[1] = 0;
  649 
  650         /* construct new IPv6 header. see RFC 2401 5.1.2.2 */
  651         /* ECN consideration. */
  652         ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
  653         if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
  654                 ip6->ip6_plen = htons(plen);
  655         else {
  656                 /* ip6->ip6_plen will be updated in ip6_output() */
  657         }
  658         ip6->ip6_nxt = IPPROTO_IPV6;
  659         sav->sah->saidx.src.sin6.sin6_addr = ip6->ip6_src;
  660         sav->sah->saidx.dst.sin6.sin6_addr = ip6->ip6_dst;
  661         ip6->ip6_hlim = IPV6_DEFHLIM;
  662 
  663         /* XXX Should ip6_src be updated later ? */
  664 
  665         return 0;
  666 }
  667 
  668 /*
  669  * IPsec output logic for IPv6, tunnel mode.
  670  */
  671 int
  672 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
  673 {
  674         struct ip6_hdr *ip6;
  675         struct ipsecrequest *isr;
  676         struct secasindex saidx;
  677         int error;
  678         struct sockaddr_in6* dst6;
  679         struct mbuf *m;
  680 
  681         IPSEC_ASSERT(state != NULL, ("ipsec6_output: null state"));
  682         IPSEC_ASSERT(state->m != NULL, ("ipsec6_output: null m"));
  683         IPSEC_ASSERT(sp != NULL, ("ipsec6_output: null sp"));
  684 
  685         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  686                 printf("ipsec6_output_tunnel: applyed SP\n");
  687                 kdebug_secpolicy(sp));
  688 
  689         m = state->m;
  690         /*
  691          * transport mode ipsec (before the 1st tunnel mode) is already
  692          * processed by ipsec6_output_trans().
  693          */
  694         for (isr = sp->req; isr; isr = isr->next) {
  695                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  696                         break;
  697         }
  698         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  699         if (isr == NULL)
  700                 goto bad;
  701 
  702         /*
  703          * There may be the case that SA status will be changed when
  704          * we are refering to one. So calling splsoftnet().
  705          */
  706         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  707                 /*
  708                  * build IPsec tunnel.
  709                  */
  710                 /* XXX should be processed with other familiy */
  711                 if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
  712                         ipseclog((LOG_ERR, "ipsec6_output_tunnel: "
  713                             "family mismatched between inner and outer, spi=%lu\n",
  714                             (u_long)ntohl(isr->sav->spi)));
  715                         newipsecstat.ips_out_inval++;
  716                         error = EAFNOSUPPORT;
  717                         goto bad;
  718                 }
  719 
  720                 m = ipsec6_splithdr(m);
  721                 if (!m) {
  722                         newipsecstat.ips_out_nomem++;
  723                         error = ENOMEM;
  724                         goto bad;
  725                 }
  726                 error = ipsec6_encapsulate(m, isr->sav);
  727                 if (error) {
  728                         m = NULL;
  729                         goto bad;
  730                 }
  731                 ip6 = mtod(m, struct ip6_hdr *);
  732 
  733                 state->ro = &isr->sav->sah->sa_route;
  734                 state->dst = (struct sockaddr *)&state->ro->ro_dst;
  735                 dst6 = (struct sockaddr_in6 *)state->dst;
  736                 if (state->ro->ro_rt
  737                  && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
  738                   || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
  739                         RTFREE(state->ro->ro_rt);
  740                         state->ro->ro_rt = NULL;
  741                 }
  742                 if (state->ro->ro_rt == 0) {
  743                         bzero(dst6, sizeof(*dst6));
  744                         dst6->sin6_family = AF_INET6;
  745                         dst6->sin6_len = sizeof(*dst6);
  746                         dst6->sin6_addr = ip6->ip6_dst;
  747                         rtalloc(state->ro);
  748                 }
  749                 if (state->ro->ro_rt == 0) {
  750                         ip6stat.ip6s_noroute++;
  751                         newipsecstat.ips_out_noroute++;
  752                         error = EHOSTUNREACH;
  753                         goto bad;
  754                 }
  755 
  756                 /* adjust state->dst if tunnel endpoint is offlink */
  757                 if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) {
  758                         state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
  759                         dst6 = (struct sockaddr_in6 *)state->dst;
  760                 }
  761         }
  762 
  763         m = ipsec6_splithdr(m);
  764         if (!m) {
  765                 newipsecstat.ips_out_nomem++;
  766                 error = ENOMEM;
  767                 goto bad;
  768         }
  769         ip6 = mtod(m, struct ip6_hdr *);
  770         return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  771                 sizeof (struct ip6_hdr),
  772                 offsetof(struct ip6_hdr, ip6_nxt));
  773 bad:
  774         if (m)
  775                 m_freem(m);
  776         state->m = NULL;
  777         return error;
  778 }
  779 #endif /*INET6*/

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