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  * $FreeBSD$
   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/pfil.h>
   48 #include <net/route.h>
   49 
   50 #include <netinet/in.h>
   51 #include <netinet/in_systm.h>
   52 #include <netinet/ip.h>
   53 #include <netinet/ip_var.h>
   54 #include <netinet/in_var.h>
   55 #include <netinet/ip_ecn.h>
   56 #ifdef INET6
   57 #include <netinet6/ip6_ecn.h>
   58 #endif
   59 
   60 #include <netinet/ip6.h>
   61 #ifdef INET6
   62 #include <netinet6/ip6_var.h>
   63 #endif
   64 #include <netinet/in_pcb.h>
   65 #ifdef INET6
   66 #include <netinet/icmp6.h>
   67 #endif
   68 
   69 #include <netipsec/ipsec.h>
   70 #ifdef INET6
   71 #include <netipsec/ipsec6.h>
   72 #endif
   73 #include <netipsec/ah_var.h>
   74 #include <netipsec/esp_var.h>
   75 #include <netipsec/ipcomp_var.h>
   76 
   77 #include <netipsec/xform.h>
   78 
   79 #include <netipsec/key.h>
   80 #include <netipsec/keydb.h>
   81 #include <netipsec/key_debug.h>
   82 
   83 #include <machine/in_cksum.h>
   84 
   85 #ifdef DEV_ENC
   86 #include <net/if_enc.h>
   87 #endif
   88 
   89 
   90 int
   91 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
   92 {
   93         struct tdb_ident *tdbi;
   94         struct m_tag *mtag;
   95         struct secasvar *sav;
   96         struct secasindex *saidx;
   97         int error;
   98 
   99         IPSEC_SPLASSERT_SOFTNET(__func__);
  100 
  101         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  102         IPSEC_ASSERT(isr != NULL, ("null ISR"));
  103         sav = isr->sav;
  104         IPSEC_ASSERT(sav != NULL, ("null SA"));
  105         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  106 
  107         saidx = &sav->sah->saidx;
  108         switch (saidx->dst.sa.sa_family) {
  109 #ifdef INET
  110         case AF_INET:
  111                 /* Fix the header length, for AH processing. */
  112                 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
  113                 break;
  114 #endif /* INET */
  115 #ifdef INET6
  116         case AF_INET6:
  117                 /* Fix the header length, for AH processing. */
  118                 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
  119                         error = ENXIO;
  120                         goto bad;
  121                 }
  122                 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
  123                         /* No jumbogram support. */
  124                         error = ENXIO;  /*?*/
  125                         goto bad;
  126                 }
  127                 mtod(m, struct ip6_hdr *)->ip6_plen =
  128                         htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  129                 break;
  130 #endif /* INET6 */
  131         default:
  132                 DPRINTF(("%s: unknown protocol family %u\n", __func__,
  133                     saidx->dst.sa.sa_family));
  134                 error = ENXIO;
  135                 goto bad;
  136         }
  137 
  138         /*
  139          * Add a record of what we've done or what needs to be done to the
  140          * packet.
  141          */
  142         mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
  143                         sizeof(struct tdb_ident), M_NOWAIT);
  144         if (mtag == NULL) {
  145                 DPRINTF(("%s: could not get packet tag\n", __func__));
  146                 error = ENOMEM;
  147                 goto bad;
  148         }
  149 
  150         tdbi = (struct tdb_ident *)(mtag + 1);
  151         tdbi->dst = saidx->dst;
  152         tdbi->proto = saidx->proto;
  153         tdbi->spi = sav->spi;
  154         m_tag_prepend(m, mtag);
  155 
  156         /*
  157          * If there's another (bundled) SA to apply, do so.
  158          * Note that this puts a burden on the kernel stack size.
  159          * If this is a problem we'll need to introduce a queue
  160          * to set the packet on so we can unwind the stack before
  161          * doing further processing.
  162          */
  163         if (isr->next) {
  164                 ipsec4stat.ips_out_bundlesa++;
  165                 return ipsec4_process_packet(m, isr->next, 0, 0);
  166         }
  167         key_sa_recordxfer(sav, m);              /* record data transfer */
  168 
  169         /*
  170          * We're done with IPsec processing, transmit the packet using the
  171          * appropriate network protocol (IP or IPv6). SPD lookup will be
  172          * performed again there.
  173          */
  174         switch (saidx->dst.sa.sa_family) {
  175 #ifdef INET
  176         struct ip *ip;
  177         case AF_INET:
  178                 ip = mtod(m, struct ip *);
  179                 ip->ip_len = ntohs(ip->ip_len);
  180                 ip->ip_off = ntohs(ip->ip_off);
  181 
  182                 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
  183 #endif /* INET */
  184 #ifdef INET6
  185         case AF_INET6:
  186                 /*
  187                  * We don't need massage, IPv6 header fields are always in
  188                  * net endian.
  189                  */
  190                 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
  191 #endif /* INET6 */
  192         }
  193         panic("ipsec_process_done");
  194 bad:
  195         m_freem(m);
  196         KEY_FREESAV(&sav);
  197         return (error);
  198 }
  199 
  200 static struct ipsecrequest *
  201 ipsec_nextisr(
  202         struct mbuf *m,
  203         struct ipsecrequest *isr,
  204         int af,
  205         struct secasindex *saidx,
  206         int *error
  207 )
  208 {
  209 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
  210                             isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
  211         struct secasvar *sav;
  212 
  213         IPSEC_SPLASSERT_SOFTNET(__func__);
  214         IPSECREQUEST_LOCK_ASSERT(isr);
  215 
  216         IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
  217                 ("invalid address family %u", af));
  218 again:
  219         /*
  220          * Craft SA index to search for proper SA.  Note that
  221          * we only fillin unspecified SA peers for transport
  222          * mode; for tunnel mode they must already be filled in.
  223          */
  224         *saidx = isr->saidx;
  225         if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
  226                 /* Fillin unspecified SA peers only for transport mode */
  227                 if (af == AF_INET) {
  228                         struct sockaddr_in *sin;
  229                         struct ip *ip = mtod(m, struct ip *);
  230 
  231                         if (saidx->src.sa.sa_len == 0) {
  232                                 sin = &saidx->src.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_src;
  237                         }
  238                         if (saidx->dst.sa.sa_len == 0) {
  239                                 sin = &saidx->dst.sin;
  240                                 sin->sin_len = sizeof(*sin);
  241                                 sin->sin_family = AF_INET;
  242                                 sin->sin_port = IPSEC_PORT_ANY;
  243                                 sin->sin_addr = ip->ip_dst;
  244                         }
  245                 } else {
  246                         struct sockaddr_in6 *sin6;
  247                         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  248 
  249                         if (saidx->src.sin6.sin6_len == 0) {
  250                                 sin6 = (struct sockaddr_in6 *)&saidx->src;
  251                                 sin6->sin6_len = sizeof(*sin6);
  252                                 sin6->sin6_family = AF_INET6;
  253                                 sin6->sin6_port = IPSEC_PORT_ANY;
  254                                 sin6->sin6_addr = ip6->ip6_src;
  255                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
  256                                         /* fix scope id for comparing SPD */
  257                                         sin6->sin6_addr.s6_addr16[1] = 0;
  258                                         sin6->sin6_scope_id =
  259                                             ntohs(ip6->ip6_src.s6_addr16[1]);
  260                                 }
  261                         }
  262                         if (saidx->dst.sin6.sin6_len == 0) {
  263                                 sin6 = (struct sockaddr_in6 *)&saidx->dst;
  264                                 sin6->sin6_len = sizeof(*sin6);
  265                                 sin6->sin6_family = AF_INET6;
  266                                 sin6->sin6_port = IPSEC_PORT_ANY;
  267                                 sin6->sin6_addr = ip6->ip6_dst;
  268                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
  269                                         /* fix scope id for comparing SPD */
  270                                         sin6->sin6_addr.s6_addr16[1] = 0;
  271                                         sin6->sin6_scope_id =
  272                                             ntohs(ip6->ip6_dst.s6_addr16[1]);
  273                                 }
  274                         }
  275                 }
  276         }
  277 
  278         /*
  279          * Lookup SA and validate it.
  280          */
  281         *error = key_checkrequest(isr, saidx);
  282         if (*error != 0) {
  283                 /*
  284                  * IPsec processing is required, but no SA found.
  285                  * I assume that key_acquire() had been called
  286                  * to get/establish the SA. Here I discard
  287                  * this packet because it is responsibility for
  288                  * upper layer to retransmit the packet.
  289                  */
  290                 ipsec4stat.ips_out_nosa++;
  291                 goto bad;
  292         }
  293         sav = isr->sav;
  294         if (sav == NULL) {
  295                 IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
  296                         ("no SA found, but required; level %u",
  297                         ipsec_get_reqlevel(isr)));
  298                 IPSECREQUEST_UNLOCK(isr);
  299                 isr = isr->next;
  300                 /*
  301                  * If isr is NULL, we found a 'use' policy w/o SA.
  302                  * Return w/o error and w/o isr so we can drop out
  303                  * and continue w/o IPsec processing.
  304                  */
  305                 if (isr == NULL)
  306                         return isr;
  307                 IPSECREQUEST_LOCK(isr);
  308                 goto again;
  309         }
  310 
  311         /*
  312          * Check system global policy controls.
  313          */
  314         if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
  315             (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
  316             (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
  317                 DPRINTF(("%s: IPsec outbound packet dropped due"
  318                         " to policy (check your sysctls)\n", __func__));
  319                 IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
  320                     ipcompstat.ipcomps_pdrops);
  321                 *error = EHOSTUNREACH;
  322                 goto bad;
  323         }
  324 
  325         /*
  326          * Sanity check the SA contents for the caller
  327          * before they invoke the xform output method.
  328          */
  329         if (sav->tdb_xform == NULL) {
  330                 DPRINTF(("%s: no transform for SA\n", __func__));
  331                 IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
  332                     ipcompstat.ipcomps_noxform);
  333                 *error = EHOSTUNREACH;
  334                 goto bad;
  335         }
  336         return isr;
  337 bad:
  338         IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
  339         IPSECREQUEST_UNLOCK(isr);
  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 error, i, off;
  359 
  360         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  361         IPSEC_ASSERT(isr != NULL, ("null isr"));
  362 
  363         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  364 
  365         isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
  366         if (isr == NULL) {
  367                 if (error != 0)
  368                         goto bad;
  369                 return EJUSTRETURN;
  370         }
  371 
  372         sav = isr->sav;
  373 
  374 #ifdef DEV_ENC
  375         encif->if_opackets++;
  376         encif->if_obytes += m->m_pkthdr.len;
  377 
  378         /* pass the mbuf to enc0 for bpf processing */
  379         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_BEFORE);
  380         /* pass the mbuf to enc0 for packet filtering */
  381         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  382                 goto bad;
  383 #endif
  384 
  385         if (!tunalready) {
  386                 union sockaddr_union *dst = &sav->sah->saidx.dst;
  387                 int setdf;
  388 
  389                 /*
  390                  * Collect IP_DF state from the outer header.
  391                  */
  392                 if (dst->sa.sa_family == AF_INET) {
  393                         if (m->m_len < sizeof (struct ip) &&
  394                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  395                                 error = ENOBUFS;
  396                                 goto bad;
  397                         }
  398                         ip = mtod(m, struct ip *);
  399                         /* Honor system-wide control of how to handle IP_DF */
  400                         switch (ip4_ipsec_dfbit) {
  401                         case 0:                 /* clear in outer header */
  402                         case 1:                 /* set in outer header */
  403                                 setdf = ip4_ipsec_dfbit;
  404                                 break;
  405                         default:                /* propagate to outer header */
  406                                 setdf = ntohs(ip->ip_off & IP_DF);
  407                                 break;
  408                         }
  409                 } else {
  410                         ip = NULL;              /* keep compiler happy */
  411                         setdf = 0;
  412                 }
  413                 /* Do the appropriate encapsulation, if necessary */
  414                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
  415                     dst->sa.sa_family != AF_INET ||         /* PF mismatch */
  416 #if 0
  417                     (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
  418                     sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
  419 #endif
  420                     (dst->sa.sa_family == AF_INET &&        /* Proxy */
  421                      dst->sin.sin_addr.s_addr != INADDR_ANY &&
  422                      dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
  423                         struct mbuf *mp;
  424 
  425                         /* Fix IPv4 header checksum and length */
  426                         if (m->m_len < sizeof (struct ip) &&
  427                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  428                                 error = ENOBUFS;
  429                                 goto bad;
  430                         }
  431                         ip = mtod(m, struct ip *);
  432                         ip->ip_len = htons(m->m_pkthdr.len);
  433                         ip->ip_sum = 0;
  434 #ifdef _IP_VHL
  435                         if (ip->ip_vhl == IP_VHL_BORING)
  436                                 ip->ip_sum = in_cksum_hdr(ip);
  437                         else
  438                                 ip->ip_sum = in_cksum(m,
  439                                         _IP_VHL_HL(ip->ip_vhl) << 2);
  440 #else
  441                         ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  442 #endif
  443 
  444                         /* Encapsulate the packet */
  445                         error = ipip_output(m, isr, &mp, 0, 0);
  446                         if (mp == NULL && !error) {
  447                                 /* Should never happen. */
  448                                 DPRINTF(("%s: ipip_output returns no mbuf and "
  449                                         "no error!", __func__));
  450                                 error = EFAULT;
  451                         }
  452                         if (error) {
  453                                 if (mp) {
  454                                         /* XXX: Should never happen! */
  455                                         m_freem(mp);
  456                                 }
  457                                 m = NULL; /* ipip_output() already freed it */
  458                                 goto bad;
  459                         }
  460                         m = mp, mp = NULL;
  461                         /*
  462                          * ipip_output clears IP_DF in the new header.  If
  463                          * we need to propagate IP_DF from the outer header,
  464                          * then we have to do it here.
  465                          *
  466                          * XXX shouldn't assume what ipip_output does.
  467                          */
  468                         if (dst->sa.sa_family == AF_INET && setdf) {
  469                                 if (m->m_len < sizeof (struct ip) &&
  470                                     (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  471                                         error = ENOBUFS;
  472                                         goto bad;
  473                                 }
  474                                 ip = mtod(m, struct ip *);
  475                                 ip->ip_off = ntohs(ip->ip_off);
  476                                 ip->ip_off |= IP_DF;
  477                                 ip->ip_off = htons(ip->ip_off);
  478                         }
  479                 }
  480         }
  481 
  482 #ifdef DEV_ENC
  483         /* pass the mbuf to enc0 for bpf processing */
  484         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_AFTER);
  485         /* pass the mbuf to enc0 for packet filtering */
  486         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  487                 goto bad;
  488 #endif
  489 
  490         /*
  491          * Dispatch to the appropriate IPsec transform logic.  The
  492          * packet will be returned for transmission after crypto
  493          * processing, etc. are completed.  For encapsulation we
  494          * bypass this call because of the explicit call done above
  495          * (necessary to deal with IP_DF handling for IPv4).
  496          *
  497          * NB: m & sav are ``passed to caller'' who's reponsible for
  498          *     for reclaiming their resources.
  499          */
  500         if (sav->tdb_xform->xf_type != XF_IP4) {
  501                 ip = mtod(m, struct ip *);
  502                 i = ip->ip_hl << 2;
  503                 off = offsetof(struct ip, ip_p);
  504                 error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
  505         } else {
  506                 error = ipsec_process_done(m, isr);
  507         }
  508         IPSECREQUEST_UNLOCK(isr);
  509         return error;
  510 bad:
  511         if (isr)
  512                 IPSECREQUEST_UNLOCK(isr);
  513         if (m)
  514                 m_freem(m);
  515         return error;
  516 }
  517 #endif
  518 
  519 #ifdef INET6
  520 /*
  521  * Chop IP6 header from the payload.
  522  */
  523 static struct mbuf *
  524 ipsec6_splithdr(struct mbuf *m)
  525 {
  526         struct mbuf *mh;
  527         struct ip6_hdr *ip6;
  528         int hlen;
  529 
  530         IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
  531                 ("first mbuf too short, len %u", m->m_len));
  532         ip6 = mtod(m, struct ip6_hdr *);
  533         hlen = sizeof(struct ip6_hdr);
  534         if (m->m_len > hlen) {
  535                 MGETHDR(mh, M_DONTWAIT, MT_DATA);
  536                 if (!mh) {
  537                         m_freem(m);
  538                         return NULL;
  539                 }
  540                 M_MOVE_PKTHDR(mh, m);
  541                 MH_ALIGN(mh, hlen);
  542                 m->m_len -= hlen;
  543                 m->m_data += hlen;
  544                 mh->m_next = m;
  545                 m = mh;
  546                 m->m_len = hlen;
  547                 bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
  548         } else if (m->m_len < hlen) {
  549                 m = m_pullup(m, hlen);
  550                 if (!m)
  551                         return NULL;
  552         }
  553         return m;
  554 }
  555 
  556 /*
  557  * IPsec output logic for IPv6, transport mode.
  558  */
  559 int
  560 ipsec6_output_trans(
  561         struct ipsec_output_state *state,
  562         u_char *nexthdrp,
  563         struct mbuf *mprev,
  564         struct secpolicy *sp,
  565         int flags,
  566         int *tun)
  567 {
  568         struct ipsecrequest *isr;
  569         struct secasindex saidx;
  570         int error = 0;
  571         struct mbuf *m;
  572 
  573         IPSEC_ASSERT(state != NULL, ("null state"));
  574         IPSEC_ASSERT(state->m != NULL, ("null m"));
  575         IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
  576         IPSEC_ASSERT(mprev != NULL, ("null mprev"));
  577         IPSEC_ASSERT(sp != NULL, ("null sp"));
  578         IPSEC_ASSERT(tun != NULL, ("null tun"));
  579 
  580         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  581                 printf("%s: applied SP\n", __func__);
  582                 kdebug_secpolicy(sp));
  583 
  584         isr = sp->req;
  585         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  586                 /* the rest will be handled by ipsec6_output_tunnel() */
  587                 *tun = 1;               /* need tunnel-mode processing */
  588                 return 0;
  589         }
  590 
  591         *tun = 0;
  592         m = state->m;
  593 
  594         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  595         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  596         if (isr == NULL) {
  597                 if (error != 0) {
  598 #ifdef notdef
  599                         /* XXX should notification be done for all errors ? */
  600                         /*
  601                          * Notify the fact that the packet is discarded
  602                          * to ourselves. I believe this is better than
  603                          * just silently discarding. (jinmei@kame.net)
  604                          * XXX: should we restrict the error to TCP packets?
  605                          * XXX: should we directly notify sockets via
  606                          *      pfctlinputs?
  607                          */
  608                         icmp6_error(m, ICMP6_DST_UNREACH,
  609                                     ICMP6_DST_UNREACH_ADMIN, 0);
  610                         m = NULL;       /* NB: icmp6_error frees mbuf */
  611 #endif
  612                         goto bad;
  613                 }
  614                 return EJUSTRETURN;
  615         }
  616 
  617         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  618                                                   sizeof (struct ip6_hdr),
  619                                                   offsetof(struct ip6_hdr, 
  620                                                            ip6_nxt));
  621         IPSECREQUEST_UNLOCK(isr);
  622         return error;
  623 bad:
  624         if (isr)
  625                 IPSECREQUEST_UNLOCK(isr);
  626         if (m)
  627                 m_freem(m);
  628         state->m = NULL;
  629         return error;
  630 }
  631 
  632 static int
  633 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
  634 {
  635         struct ip6_hdr *oip6;
  636         struct ip6_hdr *ip6;
  637         size_t plen;
  638 
  639         /* can't tunnel between different AFs */
  640         if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
  641             sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
  642                 m_freem(m);
  643                 return EINVAL;
  644         }
  645         IPSEC_ASSERT(m->m_len == sizeof (struct ip6_hdr),
  646                 ("mbuf wrong size; len %u", m->m_len));
  647 
  648 
  649         /*
  650          * grow the mbuf to accomodate the new IPv6 header.
  651          */
  652         plen = m->m_pkthdr.len;
  653         if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
  654                 struct mbuf *n;
  655                 MGET(n, M_DONTWAIT, MT_DATA);
  656                 if (!n) {
  657                         m_freem(m);
  658                         return ENOBUFS;
  659                 }
  660                 n->m_len = sizeof(struct ip6_hdr);
  661                 n->m_next = m->m_next;
  662                 m->m_next = n;
  663                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  664                 oip6 = mtod(n, struct ip6_hdr *);
  665         } else {
  666                 m->m_next->m_len += sizeof(struct ip6_hdr);
  667                 m->m_next->m_data -= sizeof(struct ip6_hdr);
  668                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  669                 oip6 = mtod(m->m_next, struct ip6_hdr *);
  670         }
  671         ip6 = mtod(m, struct ip6_hdr *);
  672         bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
  673 
  674         /* Fake link-local scope-class addresses */
  675         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
  676                 oip6->ip6_src.s6_addr16[1] = 0;
  677         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
  678                 oip6->ip6_dst.s6_addr16[1] = 0;
  679 
  680         /* construct new IPv6 header. see RFC 2401 5.1.2.2 */
  681         /* ECN consideration. */
  682         ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
  683         if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
  684                 ip6->ip6_plen = htons(plen);
  685         else {
  686                 /* ip6->ip6_plen will be updated in ip6_output() */
  687         }
  688         ip6->ip6_nxt = IPPROTO_IPV6;
  689         ip6->ip6_src = sav->sah->saidx.src.sin6.sin6_addr;
  690         ip6->ip6_dst = sav->sah->saidx.dst.sin6.sin6_addr;
  691         ip6->ip6_hlim = IPV6_DEFHLIM;
  692 
  693         /* XXX Should ip6_src be updated later ? */
  694 
  695         return 0;
  696 }
  697 
  698 /*
  699  * IPsec output logic for IPv6, tunnel mode.
  700  */
  701 int
  702 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
  703 {
  704         struct ip6_hdr *ip6;
  705         struct ipsecrequest *isr;
  706         struct secasindex saidx;
  707         int error;
  708         struct sockaddr_in6* dst6;
  709         struct mbuf *m;
  710 
  711         IPSEC_ASSERT(state != NULL, ("null state"));
  712         IPSEC_ASSERT(state->m != NULL, ("null m"));
  713         IPSEC_ASSERT(sp != NULL, ("null sp"));
  714 
  715         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  716                 printf("%s: applied SP\n", __func__);
  717                 kdebug_secpolicy(sp));
  718 
  719         m = state->m;
  720         /*
  721          * transport mode ipsec (before the 1st tunnel mode) is already
  722          * processed by ipsec6_output_trans().
  723          */
  724         for (isr = sp->req; isr; isr = isr->next) {
  725                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  726                         break;
  727         }
  728 
  729         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  730         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  731         if (isr == NULL) {
  732                 if (error != 0)
  733                         goto bad;
  734                 return EJUSTRETURN; 
  735         }
  736 
  737 #ifdef DEV_ENC
  738         /* pass the mbuf to enc0 for bpf processing */
  739         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_BEFORE);
  740         /* pass the mbuf to enc0 for packet filtering */
  741         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  742                 goto bad;
  743 #endif
  744 
  745         /*
  746          * There may be the case that SA status will be changed when
  747          * we are refering to one. So calling splsoftnet().
  748          */
  749         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  750                 /*
  751                  * build IPsec tunnel.
  752                  */
  753                 /* XXX should be processed with other familiy */
  754                 if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
  755                         ipseclog((LOG_ERR, "%s: family mismatched between "
  756                             "inner and outer, spi=%u\n", __func__,
  757                             ntohl(isr->sav->spi)));
  758                         ipsec6stat.ips_out_inval++;
  759                         error = EAFNOSUPPORT;
  760                         goto bad;
  761                 }
  762 
  763                 m = ipsec6_splithdr(m);
  764                 if (!m) {
  765                         ipsec6stat.ips_out_nomem++;
  766                         error = ENOMEM;
  767                         goto bad;
  768                 }
  769                 error = ipsec6_encapsulate(m, isr->sav);
  770                 if (error) {
  771                         m = NULL;
  772                         goto bad;
  773                 }
  774                 ip6 = mtod(m, struct ip6_hdr *);
  775 
  776                 state->ro = &isr->sav->sah->sa_route;
  777                 state->dst = (struct sockaddr *)&state->ro->ro_dst;
  778                 dst6 = (struct sockaddr_in6 *)state->dst;
  779                 if (state->ro->ro_rt
  780                  && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
  781                   || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
  782                         RTFREE(state->ro->ro_rt);
  783                         state->ro->ro_rt = NULL;
  784                 }
  785                 if (state->ro->ro_rt == 0) {
  786                         bzero(dst6, sizeof(*dst6));
  787                         dst6->sin6_family = AF_INET6;
  788                         dst6->sin6_len = sizeof(*dst6);
  789                         dst6->sin6_addr = ip6->ip6_dst;
  790                         rtalloc(state->ro);
  791                 }
  792                 if (state->ro->ro_rt == 0) {
  793                         ip6stat.ip6s_noroute++;
  794                         ipsec6stat.ips_out_noroute++;
  795                         error = EHOSTUNREACH;
  796                         goto bad;
  797                 }
  798 
  799                 /* adjust state->dst if tunnel endpoint is offlink */
  800                 if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) {
  801                         state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
  802                         dst6 = (struct sockaddr_in6 *)state->dst;
  803                 }
  804         }
  805 
  806         m = ipsec6_splithdr(m);
  807         if (!m) {
  808                 ipsec6stat.ips_out_nomem++;
  809                 error = ENOMEM;
  810                 goto bad;
  811         }
  812         ip6 = mtod(m, struct ip6_hdr *);
  813 
  814 #ifdef DEV_ENC
  815         /* pass the mbuf to enc0 for bpf processing */
  816         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_AFTER);
  817         /* pass the mbuf to enc0 for packet filtering */
  818         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  819                 goto bad;
  820 #endif
  821 
  822         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  823                 sizeof (struct ip6_hdr),
  824                 offsetof(struct ip6_hdr, ip6_nxt));
  825         IPSECREQUEST_UNLOCK(isr);
  826         return error;
  827 bad:
  828         if (isr)
  829                 IPSECREQUEST_UNLOCK(isr);
  830         if (m)
  831                 m_freem(m);
  832         state->m = NULL;
  833         return error;
  834 }
  835 #endif /*INET6*/

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