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 /*-
    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: releng/5.4/sys/netipsec/ipsec_output.c 124765 2004-01-20 22:45:10Z sam $
   27  */
   28 
   29 /*
   30  * IPsec output processing.
   31  */
   32 #include "opt_inet.h"
   33 #include "opt_inet6.h"
   34 #include "opt_ipsec.h"
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/mbuf.h>
   39 #include <sys/domain.h>
   40 #include <sys/protosw.h>
   41 #include <sys/socket.h>
   42 #include <sys/errno.h>
   43 #include <sys/syslog.h>
   44 
   45 #include <net/if.h>
   46 #include <net/route.h>
   47 
   48 #include <netinet/in.h>
   49 #include <netinet/in_systm.h>
   50 #include <netinet/ip.h>
   51 #include <netinet/ip_var.h>
   52 #include <netinet/in_var.h>
   53 #include <netinet/ip_ecn.h>
   54 #ifdef INET6
   55 #include <netinet6/ip6_ecn.h>
   56 #endif
   57 
   58 #include <netinet/ip6.h>
   59 #ifdef INET6
   60 #include <netinet6/ip6_var.h>
   61 #endif
   62 #include <netinet/in_pcb.h>
   63 #ifdef INET6
   64 #include <netinet/icmp6.h>
   65 #endif
   66 
   67 #include <netipsec/ipsec.h>
   68 #ifdef INET6
   69 #include <netipsec/ipsec6.h>
   70 #endif
   71 #include <netipsec/ah_var.h>
   72 #include <netipsec/esp_var.h>
   73 #include <netipsec/ipcomp_var.h>
   74 
   75 #include <netipsec/xform.h>
   76 
   77 #include <netipsec/key.h>
   78 #include <netipsec/keydb.h>
   79 #include <netipsec/key_debug.h>
   80 
   81 #include <machine/in_cksum.h>
   82 
   83 int
   84 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
   85 {
   86         struct tdb_ident *tdbi;
   87         struct m_tag *mtag;
   88         struct secasvar *sav;
   89         struct secasindex *saidx;
   90         int error;
   91 
   92         IPSEC_SPLASSERT_SOFTNET(__func__);
   93 
   94         IPSEC_ASSERT(m != NULL, ("null mbuf"));
   95         IPSEC_ASSERT(isr != NULL, ("null ISR"));
   96         sav = isr->sav;
   97         IPSEC_ASSERT(sav != NULL, ("null SA"));
   98         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
   99 
  100         saidx = &sav->sah->saidx;
  101         switch (saidx->dst.sa.sa_family) {
  102 #ifdef INET
  103         case AF_INET:
  104                 /* Fix the header length, for AH processing. */
  105                 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
  106                 break;
  107 #endif /* INET */
  108 #ifdef INET6
  109         case AF_INET6:
  110                 /* Fix the header length, for AH processing. */
  111                 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
  112                         error = ENXIO;
  113                         goto bad;
  114                 }
  115                 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
  116                         /* No jumbogram support. */
  117                         error = ENXIO;  /*?*/
  118                         goto bad;
  119                 }
  120                 mtod(m, struct ip6_hdr *)->ip6_plen =
  121                         htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  122                 break;
  123 #endif /* INET6 */
  124         default:
  125                 DPRINTF(("%s: unknown protocol family %u\n", __func__,
  126                     saidx->dst.sa.sa_family));
  127                 error = ENXIO;
  128                 goto bad;
  129         }
  130 
  131         /*
  132          * Add a record of what we've done or what needs to be done to the
  133          * packet.
  134          */
  135         mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
  136                         sizeof(struct tdb_ident), M_NOWAIT);
  137         if (mtag == NULL) {
  138                 DPRINTF(("%s: could not get packet tag\n", __func__));
  139                 error = ENOMEM;
  140                 goto bad;
  141         }
  142 
  143         tdbi = (struct tdb_ident *)(mtag + 1);
  144         tdbi->dst = saidx->dst;
  145         tdbi->proto = saidx->proto;
  146         tdbi->spi = sav->spi;
  147         m_tag_prepend(m, mtag);
  148 
  149         /*
  150          * If there's another (bundled) SA to apply, do so.
  151          * Note that this puts a burden on the kernel stack size.
  152          * If this is a problem we'll need to introduce a queue
  153          * to set the packet on so we can unwind the stack before
  154          * doing further processing.
  155          */
  156         if (isr->next) {
  157                 newipsecstat.ips_out_bundlesa++;
  158                 return ipsec4_process_packet(m, isr->next, 0, 0);
  159         }
  160         key_sa_recordxfer(sav, m);              /* record data transfer */
  161 
  162         /*
  163          * We're done with IPsec processing, transmit the packet using the
  164          * appropriate network protocol (IP or IPv6). SPD lookup will be
  165          * performed again there.
  166          */
  167         switch (saidx->dst.sa.sa_family) {
  168 #ifdef INET
  169         struct ip *ip;
  170         case AF_INET:
  171                 ip = mtod(m, struct ip *);
  172                 ip->ip_len = ntohs(ip->ip_len);
  173                 ip->ip_off = ntohs(ip->ip_off);
  174 
  175                 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
  176 #endif /* INET */
  177 #ifdef INET6
  178         case AF_INET6:
  179                 /*
  180                  * We don't need massage, IPv6 header fields are always in
  181                  * net endian.
  182                  */
  183                 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
  184 #endif /* INET6 */
  185         }
  186         panic("ipsec_process_done");
  187 bad:
  188         m_freem(m);
  189         KEY_FREESAV(&sav);
  190         return (error);
  191 }
  192 
  193 static struct ipsecrequest *
  194 ipsec_nextisr(
  195         struct mbuf *m,
  196         struct ipsecrequest *isr,
  197         int af,
  198         struct secasindex *saidx,
  199         int *error
  200 )
  201 {
  202 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
  203                             isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
  204         struct secasvar *sav;
  205 
  206         IPSEC_SPLASSERT_SOFTNET(__func__);
  207         IPSECREQUEST_LOCK_ASSERT(isr);
  208 
  209         IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
  210                 ("invalid address family %u", af));
  211 again:
  212         /*
  213          * Craft SA index to search for proper SA.  Note that
  214          * we only fillin unspecified SA peers for transport
  215          * mode; for tunnel mode they must already be filled in.
  216          */
  217         *saidx = isr->saidx;
  218         if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
  219                 /* Fillin unspecified SA peers only for transport mode */
  220                 if (af == AF_INET) {
  221                         struct sockaddr_in *sin;
  222                         struct ip *ip = mtod(m, struct ip *);
  223 
  224                         if (saidx->src.sa.sa_len == 0) {
  225                                 sin = &saidx->src.sin;
  226                                 sin->sin_len = sizeof(*sin);
  227                                 sin->sin_family = AF_INET;
  228                                 sin->sin_port = IPSEC_PORT_ANY;
  229                                 sin->sin_addr = ip->ip_src;
  230                         }
  231                         if (saidx->dst.sa.sa_len == 0) {
  232                                 sin = &saidx->dst.sin;
  233                                 sin->sin_len = sizeof(*sin);
  234                                 sin->sin_family = AF_INET;
  235                                 sin->sin_port = IPSEC_PORT_ANY;
  236                                 sin->sin_addr = ip->ip_dst;
  237                         }
  238                 } else {
  239                         struct sockaddr_in6 *sin6;
  240                         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  241 
  242                         if (saidx->src.sin6.sin6_len == 0) {
  243                                 sin6 = (struct sockaddr_in6 *)&saidx->src;
  244                                 sin6->sin6_len = sizeof(*sin6);
  245                                 sin6->sin6_family = AF_INET6;
  246                                 sin6->sin6_port = IPSEC_PORT_ANY;
  247                                 sin6->sin6_addr = ip6->ip6_src;
  248                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
  249                                         /* fix scope id for comparing SPD */
  250                                         sin6->sin6_addr.s6_addr16[1] = 0;
  251                                         sin6->sin6_scope_id =
  252                                             ntohs(ip6->ip6_src.s6_addr16[1]);
  253                                 }
  254                         }
  255                         if (saidx->dst.sin6.sin6_len == 0) {
  256                                 sin6 = (struct sockaddr_in6 *)&saidx->dst;
  257                                 sin6->sin6_len = sizeof(*sin6);
  258                                 sin6->sin6_family = AF_INET6;
  259                                 sin6->sin6_port = IPSEC_PORT_ANY;
  260                                 sin6->sin6_addr = ip6->ip6_dst;
  261                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
  262                                         /* fix scope id for comparing SPD */
  263                                         sin6->sin6_addr.s6_addr16[1] = 0;
  264                                         sin6->sin6_scope_id =
  265                                             ntohs(ip6->ip6_dst.s6_addr16[1]);
  266                                 }
  267                         }
  268                 }
  269         }
  270 
  271         /*
  272          * Lookup SA and validate it.
  273          */
  274         *error = key_checkrequest(isr, saidx);
  275         if (*error != 0) {
  276                 /*
  277                  * IPsec processing is required, but no SA found.
  278                  * I assume that key_acquire() had been called
  279                  * to get/establish the SA. Here I discard
  280                  * this packet because it is responsibility for
  281                  * upper layer to retransmit the packet.
  282                  */
  283                 newipsecstat.ips_out_nosa++;
  284                 goto bad;
  285         }
  286         sav = isr->sav;
  287         if (sav == NULL) {              /* XXX valid return */
  288                 IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
  289                         ("no SA found, but required; level %u",
  290                         ipsec_get_reqlevel(isr)));
  291                 IPSECREQUEST_UNLOCK(isr);
  292                 isr = isr->next;
  293                 if (isr == NULL) {
  294                         /*XXXstatistic??*/
  295                         *error = EINVAL;                /*XXX*/
  296                         return isr;
  297                 }
  298                 IPSECREQUEST_LOCK(isr);
  299                 goto again;
  300         }
  301 
  302         /*
  303          * Check system global policy controls.
  304          */
  305         if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
  306             (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
  307             (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
  308                 DPRINTF(("%s: IPsec outbound packet dropped due"
  309                         " to policy (check your sysctls)\n", __func__));
  310                 IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
  311                     ipcompstat.ipcomps_pdrops);
  312                 *error = EHOSTUNREACH;
  313                 goto bad;
  314         }
  315 
  316         /*
  317          * Sanity check the SA contents for the caller
  318          * before they invoke the xform output method.
  319          */
  320         if (sav->tdb_xform == NULL) {
  321                 DPRINTF(("%s: no transform for SA\n", __func__));
  322                 IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
  323                     ipcompstat.ipcomps_noxform);
  324                 *error = EHOSTUNREACH;
  325                 goto bad;
  326         }
  327         return isr;
  328 bad:
  329         IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
  330         IPSECREQUEST_UNLOCK(isr);
  331         return NULL;
  332 #undef IPSEC_OSTAT
  333 }
  334 
  335 #ifdef INET
  336 /*
  337  * IPsec output logic for IPv4.
  338  */
  339 int
  340 ipsec4_process_packet(
  341         struct mbuf *m,
  342         struct ipsecrequest *isr,
  343         int flags,
  344         int tunalready)
  345 {
  346         struct secasindex saidx;
  347         struct secasvar *sav;
  348         struct ip *ip;
  349         int error, i, off;
  350 
  351         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  352         IPSEC_ASSERT(isr != NULL, ("null isr"));
  353 
  354         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  355 
  356         isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
  357         if (isr == NULL)
  358                 goto bad;
  359 
  360         sav = isr->sav;
  361         if (!tunalready) {
  362                 union sockaddr_union *dst = &sav->sah->saidx.dst;
  363                 int setdf;
  364 
  365                 /*
  366                  * Collect IP_DF state from the outer header.
  367                  */
  368                 if (dst->sa.sa_family == AF_INET) {
  369                         if (m->m_len < sizeof (struct ip) &&
  370                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  371                                 error = ENOBUFS;
  372                                 goto bad;
  373                         }
  374                         ip = mtod(m, struct ip *);
  375                         /* Honor system-wide control of how to handle IP_DF */
  376                         switch (ip4_ipsec_dfbit) {
  377                         case 0:                 /* clear in outer header */
  378                         case 1:                 /* set in outer header */
  379                                 setdf = ip4_ipsec_dfbit;
  380                                 break;
  381                         default:                /* propagate to outer header */
  382                                 setdf = ntohs(ip->ip_off & IP_DF);
  383                                 break;
  384                         }
  385                 } else {
  386                         ip = NULL;              /* keep compiler happy */
  387                         setdf = 0;
  388                 }
  389                 /* Do the appropriate encapsulation, if necessary */
  390                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
  391                     dst->sa.sa_family != AF_INET ||         /* PF mismatch */
  392 #if 0
  393                     (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
  394                     sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
  395 #endif
  396                     (dst->sa.sa_family == AF_INET &&        /* Proxy */
  397                      dst->sin.sin_addr.s_addr != INADDR_ANY &&
  398                      dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
  399                         struct mbuf *mp;
  400 
  401                         /* Fix IPv4 header checksum and length */
  402                         if (m->m_len < sizeof (struct ip) &&
  403                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  404                                 error = ENOBUFS;
  405                                 goto bad;
  406                         }
  407                         ip = mtod(m, struct ip *);
  408                         ip->ip_len = htons(m->m_pkthdr.len);
  409                         ip->ip_sum = 0;
  410 #ifdef _IP_VHL
  411                         if (ip->ip_vhl == IP_VHL_BORING)
  412                                 ip->ip_sum = in_cksum_hdr(ip);
  413                         else
  414                                 ip->ip_sum = in_cksum(m,
  415                                         _IP_VHL_HL(ip->ip_vhl) << 2);
  416 #else
  417                         ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  418 #endif
  419 
  420                         /* Encapsulate the packet */
  421                         error = ipip_output(m, isr, &mp, 0, 0);
  422                         if (mp == NULL && !error) {
  423                                 /* Should never happen. */
  424                                 DPRINTF(("%s: ipip_output returns no mbuf and "
  425                                         "no error!", __func__));
  426                                 error = EFAULT;
  427                         }
  428                         if (error) {
  429                                 if (mp) {
  430                                         /* XXX: Should never happen! */
  431                                         m_freem(mp);
  432                                 }
  433                                 m = NULL; /* ipip_output() already freed it */
  434                                 goto bad;
  435                         }
  436                         m = mp, mp = NULL;
  437                         /*
  438                          * ipip_output clears IP_DF in the new header.  If
  439                          * we need to propagate IP_DF from the outer header,
  440                          * then we have to do it here.
  441                          *
  442                          * XXX shouldn't assume what ipip_output does.
  443                          */
  444                         if (dst->sa.sa_family == AF_INET && setdf) {
  445                                 if (m->m_len < sizeof (struct ip) &&
  446                                     (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  447                                         error = ENOBUFS;
  448                                         goto bad;
  449                                 }
  450                                 ip = mtod(m, struct ip *);
  451                                 ip->ip_off = ntohs(ip->ip_off);
  452                                 ip->ip_off |= IP_DF;
  453                                 ip->ip_off = htons(ip->ip_off);
  454                         }
  455                 }
  456         }
  457 
  458         /*
  459          * Dispatch to the appropriate IPsec transform logic.  The
  460          * packet will be returned for transmission after crypto
  461          * processing, etc. are completed.  For encapsulation we
  462          * bypass this call because of the explicit call done above
  463          * (necessary to deal with IP_DF handling for IPv4).
  464          *
  465          * NB: m & sav are ``passed to caller'' who's reponsible for
  466          *     for reclaiming their resources.
  467          */
  468         if (sav->tdb_xform->xf_type != XF_IP4) {
  469                 ip = mtod(m, struct ip *);
  470                 i = ip->ip_hl << 2;
  471                 off = offsetof(struct ip, ip_p);
  472                 error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
  473         } else {
  474                 error = ipsec_process_done(m, isr);
  475         }
  476         IPSECREQUEST_UNLOCK(isr);
  477         return error;
  478 bad:
  479         if (isr)
  480                 IPSECREQUEST_UNLOCK(isr);
  481         if (m)
  482                 m_freem(m);
  483         return error;
  484 }
  485 #endif
  486 
  487 #ifdef INET6
  488 /*
  489  * Chop IP6 header from the payload.
  490  */
  491 static struct mbuf *
  492 ipsec6_splithdr(struct mbuf *m)
  493 {
  494         struct mbuf *mh;
  495         struct ip6_hdr *ip6;
  496         int hlen;
  497 
  498         IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
  499                 ("first mbuf too short, len %u", m->m_len));
  500         ip6 = mtod(m, struct ip6_hdr *);
  501         hlen = sizeof(struct ip6_hdr);
  502         if (m->m_len > hlen) {
  503                 MGETHDR(mh, M_DONTWAIT, MT_HEADER);
  504                 if (!mh) {
  505                         m_freem(m);
  506                         return NULL;
  507                 }
  508                 M_MOVE_PKTHDR(mh, m);
  509                 MH_ALIGN(mh, hlen);
  510                 m->m_len -= hlen;
  511                 m->m_data += hlen;
  512                 mh->m_next = m;
  513                 m = mh;
  514                 m->m_len = hlen;
  515                 bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
  516         } else if (m->m_len < hlen) {
  517                 m = m_pullup(m, hlen);
  518                 if (!m)
  519                         return NULL;
  520         }
  521         return m;
  522 }
  523 
  524 /*
  525  * IPsec output logic for IPv6, transport mode.
  526  */
  527 int
  528 ipsec6_output_trans(
  529         struct ipsec_output_state *state,
  530         u_char *nexthdrp,
  531         struct mbuf *mprev,
  532         struct secpolicy *sp,
  533         int flags,
  534         int *tun)
  535 {
  536         struct ipsecrequest *isr;
  537         struct secasindex saidx;
  538         int error = 0;
  539         struct mbuf *m;
  540 
  541         IPSEC_ASSERT(state != NULL, ("null state"));
  542         IPSEC_ASSERT(state->m != NULL, ("null m"));
  543         IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
  544         IPSEC_ASSERT(mprev != NULL, ("null mprev"));
  545         IPSEC_ASSERT(sp != NULL, ("null sp"));
  546         IPSEC_ASSERT(tun != NULL, ("null tun"));
  547 
  548         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  549                 printf("%s: applyed SP\n", __func__);
  550                 kdebug_secpolicy(sp));
  551 
  552         isr = sp->req;
  553         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  554                 /* the rest will be handled by ipsec6_output_tunnel() */
  555                 *tun = 1;               /* need tunnel-mode processing */
  556                 return 0;
  557         }
  558 
  559         *tun = 0;
  560         m = state->m;
  561 
  562         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  563         if (isr == NULL) {
  564 #ifdef notdef
  565                 /* XXX should notification be done for all errors ? */
  566                 /*
  567                  * Notify the fact that the packet is discarded
  568                  * to ourselves. I believe this is better than
  569                  * just silently discarding. (jinmei@kame.net)
  570                  * XXX: should we restrict the error to TCP packets?
  571                  * XXX: should we directly notify sockets via
  572                  *      pfctlinputs?
  573                  */
  574                 icmp6_error(m, ICMP6_DST_UNREACH,
  575                             ICMP6_DST_UNREACH_ADMIN, 0);
  576                 m = NULL;       /* NB: icmp6_error frees mbuf */
  577 #endif
  578                 goto bad;
  579         }
  580 
  581         return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  582                 sizeof (struct ip6_hdr),
  583                 offsetof(struct ip6_hdr, ip6_nxt));
  584 bad:
  585         if (m)
  586                 m_freem(m);
  587         state->m = NULL;
  588         return error;
  589 }
  590 
  591 static int
  592 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
  593 {
  594         struct ip6_hdr *oip6;
  595         struct ip6_hdr *ip6;
  596         size_t plen;
  597 
  598         /* can't tunnel between different AFs */
  599         if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
  600             sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
  601                 m_freem(m);
  602                 return EINVAL;
  603         }
  604         IPSEC_ASSERT(m->m_len != sizeof (struct ip6_hdr),
  605                 ("mbuf wrong size; len %u", m->m_len));
  606 
  607 
  608         /*
  609          * grow the mbuf to accomodate the new IPv6 header.
  610          */
  611         plen = m->m_pkthdr.len;
  612         if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
  613                 struct mbuf *n;
  614                 MGET(n, M_DONTWAIT, MT_DATA);
  615                 if (!n) {
  616                         m_freem(m);
  617                         return ENOBUFS;
  618                 }
  619                 n->m_len = sizeof(struct ip6_hdr);
  620                 n->m_next = m->m_next;
  621                 m->m_next = n;
  622                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  623                 oip6 = mtod(n, struct ip6_hdr *);
  624         } else {
  625                 m->m_next->m_len += sizeof(struct ip6_hdr);
  626                 m->m_next->m_data -= sizeof(struct ip6_hdr);
  627                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  628                 oip6 = mtod(m->m_next, struct ip6_hdr *);
  629         }
  630         ip6 = mtod(m, struct ip6_hdr *);
  631         bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
  632 
  633         /* Fake link-local scope-class addresses */
  634         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
  635                 oip6->ip6_src.s6_addr16[1] = 0;
  636         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
  637                 oip6->ip6_dst.s6_addr16[1] = 0;
  638 
  639         /* construct new IPv6 header. see RFC 2401 5.1.2.2 */
  640         /* ECN consideration. */
  641         ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
  642         if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
  643                 ip6->ip6_plen = htons(plen);
  644         else {
  645                 /* ip6->ip6_plen will be updated in ip6_output() */
  646         }
  647         ip6->ip6_nxt = IPPROTO_IPV6;
  648         sav->sah->saidx.src.sin6.sin6_addr = ip6->ip6_src;
  649         sav->sah->saidx.dst.sin6.sin6_addr = ip6->ip6_dst;
  650         ip6->ip6_hlim = IPV6_DEFHLIM;
  651 
  652         /* XXX Should ip6_src be updated later ? */
  653 
  654         return 0;
  655 }
  656 
  657 /*
  658  * IPsec output logic for IPv6, tunnel mode.
  659  */
  660 int
  661 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
  662 {
  663         struct ip6_hdr *ip6;
  664         struct ipsecrequest *isr;
  665         struct secasindex saidx;
  666         int error;
  667         struct sockaddr_in6* dst6;
  668         struct mbuf *m;
  669 
  670         IPSEC_ASSERT(state != NULL, ("null state"));
  671         IPSEC_ASSERT(state->m != NULL, ("null m"));
  672         IPSEC_ASSERT(sp != NULL, ("null sp"));
  673 
  674         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  675                 printf("%s: applyed SP\n", __func__);
  676                 kdebug_secpolicy(sp));
  677 
  678         m = state->m;
  679         /*
  680          * transport mode ipsec (before the 1st tunnel mode) is already
  681          * processed by ipsec6_output_trans().
  682          */
  683         for (isr = sp->req; isr; isr = isr->next) {
  684                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  685                         break;
  686         }
  687         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  688         if (isr == NULL)
  689                 goto bad;
  690 
  691         /*
  692          * There may be the case that SA status will be changed when
  693          * we are refering to one. So calling splsoftnet().
  694          */
  695         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  696                 /*
  697                  * build IPsec tunnel.
  698                  */
  699                 /* XXX should be processed with other familiy */
  700                 if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
  701                         ipseclog((LOG_ERR, "%s: family mismatched between "
  702                             "inner and outer, spi=%u\n", __func__,
  703                             ntohl(isr->sav->spi)));
  704                         newipsecstat.ips_out_inval++;
  705                         error = EAFNOSUPPORT;
  706                         goto bad;
  707                 }
  708 
  709                 m = ipsec6_splithdr(m);
  710                 if (!m) {
  711                         newipsecstat.ips_out_nomem++;
  712                         error = ENOMEM;
  713                         goto bad;
  714                 }
  715                 error = ipsec6_encapsulate(m, isr->sav);
  716                 if (error) {
  717                         m = NULL;
  718                         goto bad;
  719                 }
  720                 ip6 = mtod(m, struct ip6_hdr *);
  721 
  722                 state->ro = &isr->sav->sah->sa_route;
  723                 state->dst = (struct sockaddr *)&state->ro->ro_dst;
  724                 dst6 = (struct sockaddr_in6 *)state->dst;
  725                 if (state->ro->ro_rt
  726                  && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
  727                   || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
  728                         RTFREE(state->ro->ro_rt);
  729                         state->ro->ro_rt = NULL;
  730                 }
  731                 if (state->ro->ro_rt == 0) {
  732                         bzero(dst6, sizeof(*dst6));
  733                         dst6->sin6_family = AF_INET6;
  734                         dst6->sin6_len = sizeof(*dst6);
  735                         dst6->sin6_addr = ip6->ip6_dst;
  736                         rtalloc(state->ro);
  737                 }
  738                 if (state->ro->ro_rt == 0) {
  739                         ip6stat.ip6s_noroute++;
  740                         newipsecstat.ips_out_noroute++;
  741                         error = EHOSTUNREACH;
  742                         goto bad;
  743                 }
  744 
  745                 /* adjust state->dst if tunnel endpoint is offlink */
  746                 if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) {
  747                         state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
  748                         dst6 = (struct sockaddr_in6 *)state->dst;
  749                 }
  750         }
  751 
  752         m = ipsec6_splithdr(m);
  753         if (!m) {
  754                 newipsecstat.ips_out_nomem++;
  755                 error = ENOMEM;
  756                 goto bad;
  757         }
  758         ip6 = mtod(m, struct ip6_hdr *);
  759         return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  760                 sizeof (struct ip6_hdr),
  761                 offsetof(struct ip6_hdr, ip6_nxt));
  762 bad:
  763         if (m)
  764                 m_freem(m);
  765         state->m = NULL;
  766         return error;
  767 }
  768 #endif /*INET6*/

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