The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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/8.2/sys/netipsec/ipsec_output.c 214882 2010-11-06 14:46:24Z bz $
   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 #include <net/vnet.h>
   50 
   51 #include <netinet/in.h>
   52 #include <netinet/in_systm.h>
   53 #include <netinet/ip.h>
   54 #include <netinet/ip_var.h>
   55 #include <netinet/in_var.h>
   56 #include <netinet/ip_ecn.h>
   57 #ifdef INET6
   58 #include <netinet6/ip6_ecn.h>
   59 #endif
   60 
   61 #include <netinet/ip6.h>
   62 #ifdef INET6
   63 #include <netinet6/ip6_var.h>
   64 #endif
   65 #include <netinet/in_pcb.h>
   66 #ifdef INET6
   67 #include <netinet/icmp6.h>
   68 #endif
   69 
   70 #include <netipsec/ipsec.h>
   71 #ifdef INET6
   72 #include <netipsec/ipsec6.h>
   73 #endif
   74 #include <netipsec/ah_var.h>
   75 #include <netipsec/esp_var.h>
   76 #include <netipsec/ipcomp_var.h>
   77 
   78 #include <netipsec/xform.h>
   79 
   80 #include <netipsec/key.h>
   81 #include <netipsec/keydb.h>
   82 #include <netipsec/key_debug.h>
   83 
   84 #include <machine/in_cksum.h>
   85 
   86 #ifdef IPSEC_NAT_T
   87 #include <netinet/udp.h>
   88 #endif
   89 
   90 #ifdef DEV_ENC
   91 #include <net/if_enc.h>
   92 #endif
   93 
   94 
   95 int
   96 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
   97 {
   98         struct tdb_ident *tdbi;
   99         struct m_tag *mtag;
  100         struct secasvar *sav;
  101         struct secasindex *saidx;
  102         int error;
  103 
  104         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  105         IPSEC_ASSERT(isr != NULL, ("null ISR"));
  106         sav = isr->sav;
  107         IPSEC_ASSERT(sav != NULL, ("null SA"));
  108         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  109 
  110         saidx = &sav->sah->saidx;
  111         switch (saidx->dst.sa.sa_family) {
  112 #ifdef INET
  113         case AF_INET:
  114                 /* Fix the header length, for AH processing. */
  115                 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
  116                 break;
  117 #endif /* INET */
  118 #ifdef INET6
  119         case AF_INET6:
  120                 /* Fix the header length, for AH processing. */
  121                 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
  122                         error = ENXIO;
  123                         goto bad;
  124                 }
  125                 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
  126                         /* No jumbogram support. */
  127                         error = ENXIO;  /*?*/
  128                         goto bad;
  129                 }
  130                 mtod(m, struct ip6_hdr *)->ip6_plen =
  131                         htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  132                 break;
  133 #endif /* INET6 */
  134         default:
  135                 DPRINTF(("%s: unknown protocol family %u\n", __func__,
  136                     saidx->dst.sa.sa_family));
  137                 error = ENXIO;
  138                 goto bad;
  139         }
  140 
  141         /*
  142          * Add a record of what we've done or what needs to be done to the
  143          * packet.
  144          */
  145         mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
  146                         sizeof(struct tdb_ident), M_NOWAIT);
  147         if (mtag == NULL) {
  148                 DPRINTF(("%s: could not get packet tag\n", __func__));
  149                 error = ENOMEM;
  150                 goto bad;
  151         }
  152 
  153         tdbi = (struct tdb_ident *)(mtag + 1);
  154         tdbi->dst = saidx->dst;
  155         tdbi->proto = saidx->proto;
  156         tdbi->spi = sav->spi;
  157         m_tag_prepend(m, mtag);
  158 
  159         /*
  160          * If there's another (bundled) SA to apply, do so.
  161          * Note that this puts a burden on the kernel stack size.
  162          * If this is a problem we'll need to introduce a queue
  163          * to set the packet on so we can unwind the stack before
  164          * doing further processing.
  165          */
  166         if (isr->next) {
  167                 V_ipsec4stat.ips_out_bundlesa++;
  168                 return ipsec4_process_packet(m, isr->next, 0, 0);
  169         }
  170         key_sa_recordxfer(sav, m);              /* record data transfer */
  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                 ip->ip_len = ntohs(ip->ip_len);
  183                 ip->ip_off = ntohs(ip->ip_off);
  184 
  185 #ifdef IPSEC_NAT_T
  186                 /*
  187                  * If NAT-T is enabled, now that all IPsec processing is done
  188                  * insert UDP encapsulation header after IP header.
  189                  */
  190                 if (sav->natt_type) {
  191 #ifdef _IP_VHL
  192                         const int hlen = IP_VHL_HL(ip->ip_vhl);
  193 #else
  194                         const int hlen = (ip->ip_hl << 2);
  195 #endif
  196                         int size, off;
  197                         struct mbuf *mi;
  198                         struct udphdr *udp;
  199 
  200                         size = sizeof(struct udphdr);
  201                         if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
  202                                 /*
  203                                  * draft-ietf-ipsec-nat-t-ike-0[01].txt and
  204                                  * draft-ietf-ipsec-udp-encaps-(00/)01.txt,
  205                                  * ignoring possible AH mode
  206                                  * non-IKE marker + non-ESP marker
  207                                  * from draft-ietf-ipsec-udp-encaps-00.txt.
  208                                  */
  209                                 size += sizeof(u_int64_t);
  210                         }
  211                         mi = m_makespace(m, hlen, size, &off);
  212                         if (mi == NULL) {
  213                                 DPRINTF(("%s: m_makespace for udphdr failed\n",
  214                                     __func__));
  215                                 error = ENOBUFS;
  216                                 goto bad;
  217                         }
  218 
  219                         udp = (struct udphdr *)(mtod(mi, caddr_t) + off);
  220                         if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
  221                                 udp->uh_sport = htons(UDP_ENCAP_ESPINUDP_PORT);
  222                         else
  223                                 udp->uh_sport =
  224                                         KEY_PORTFROMSADDR(&sav->sah->saidx.src);
  225                         udp->uh_dport = KEY_PORTFROMSADDR(&sav->sah->saidx.dst);
  226                         udp->uh_sum = 0;
  227                         udp->uh_ulen = htons(m->m_pkthdr.len - hlen);
  228                         ip->ip_len = m->m_pkthdr.len;
  229                         ip->ip_p = IPPROTO_UDP;
  230 
  231                         if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
  232                                 *(u_int64_t *)(udp + 1) = 0;
  233                 }
  234 #endif /* IPSEC_NAT_T */
  235 
  236                 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
  237 #endif /* INET */
  238 #ifdef INET6
  239         case AF_INET6:
  240                 /*
  241                  * We don't need massage, IPv6 header fields are always in
  242                  * net endian.
  243                  */
  244                 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
  245 #endif /* INET6 */
  246         }
  247         panic("ipsec_process_done");
  248 bad:
  249         m_freem(m);
  250         KEY_FREESAV(&sav);
  251         return (error);
  252 }
  253 
  254 static struct ipsecrequest *
  255 ipsec_nextisr(
  256         struct mbuf *m,
  257         struct ipsecrequest *isr,
  258         int af,
  259         struct secasindex *saidx,
  260         int *error
  261 )
  262 {
  263 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
  264                             isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
  265         struct secasvar *sav;
  266 
  267         IPSECREQUEST_LOCK_ASSERT(isr);
  268 
  269         IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
  270                 ("invalid address family %u", af));
  271 again:
  272         /*
  273          * Craft SA index to search for proper SA.  Note that
  274          * we only fillin unspecified SA peers for transport
  275          * mode; for tunnel mode they must already be filled in.
  276          */
  277         *saidx = isr->saidx;
  278         if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
  279                 /* Fillin unspecified SA peers only for transport mode */
  280                 if (af == AF_INET) {
  281                         struct sockaddr_in *sin;
  282                         struct ip *ip = mtod(m, struct ip *);
  283 
  284                         if (saidx->src.sa.sa_len == 0) {
  285                                 sin = &saidx->src.sin;
  286                                 sin->sin_len = sizeof(*sin);
  287                                 sin->sin_family = AF_INET;
  288                                 sin->sin_port = IPSEC_PORT_ANY;
  289                                 sin->sin_addr = ip->ip_src;
  290                         }
  291                         if (saidx->dst.sa.sa_len == 0) {
  292                                 sin = &saidx->dst.sin;
  293                                 sin->sin_len = sizeof(*sin);
  294                                 sin->sin_family = AF_INET;
  295                                 sin->sin_port = IPSEC_PORT_ANY;
  296                                 sin->sin_addr = ip->ip_dst;
  297                         }
  298                 } else {
  299                         struct sockaddr_in6 *sin6;
  300                         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  301 
  302                         if (saidx->src.sin6.sin6_len == 0) {
  303                                 sin6 = (struct sockaddr_in6 *)&saidx->src;
  304                                 sin6->sin6_len = sizeof(*sin6);
  305                                 sin6->sin6_family = AF_INET6;
  306                                 sin6->sin6_port = IPSEC_PORT_ANY;
  307                                 sin6->sin6_addr = ip6->ip6_src;
  308                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
  309                                         /* fix scope id for comparing SPD */
  310                                         sin6->sin6_addr.s6_addr16[1] = 0;
  311                                         sin6->sin6_scope_id =
  312                                             ntohs(ip6->ip6_src.s6_addr16[1]);
  313                                 }
  314                         }
  315                         if (saidx->dst.sin6.sin6_len == 0) {
  316                                 sin6 = (struct sockaddr_in6 *)&saidx->dst;
  317                                 sin6->sin6_len = sizeof(*sin6);
  318                                 sin6->sin6_family = AF_INET6;
  319                                 sin6->sin6_port = IPSEC_PORT_ANY;
  320                                 sin6->sin6_addr = ip6->ip6_dst;
  321                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
  322                                         /* fix scope id for comparing SPD */
  323                                         sin6->sin6_addr.s6_addr16[1] = 0;
  324                                         sin6->sin6_scope_id =
  325                                             ntohs(ip6->ip6_dst.s6_addr16[1]);
  326                                 }
  327                         }
  328                 }
  329         }
  330 
  331         /*
  332          * Lookup SA and validate it.
  333          */
  334         *error = key_checkrequest(isr, saidx);
  335         if (*error != 0) {
  336                 /*
  337                  * IPsec processing is required, but no SA found.
  338                  * I assume that key_acquire() had been called
  339                  * to get/establish the SA. Here I discard
  340                  * this packet because it is responsibility for
  341                  * upper layer to retransmit the packet.
  342                  */
  343                 V_ipsec4stat.ips_out_nosa++;
  344                 goto bad;
  345         }
  346         sav = isr->sav;
  347         if (sav == NULL) {
  348                 IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
  349                         ("no SA found, but required; level %u",
  350                         ipsec_get_reqlevel(isr)));
  351                 IPSECREQUEST_UNLOCK(isr);
  352                 isr = isr->next;
  353                 /*
  354                  * If isr is NULL, we found a 'use' policy w/o SA.
  355                  * Return w/o error and w/o isr so we can drop out
  356                  * and continue w/o IPsec processing.
  357                  */
  358                 if (isr == NULL)
  359                         return isr;
  360                 IPSECREQUEST_LOCK(isr);
  361                 goto again;
  362         }
  363 
  364         /*
  365          * Check system global policy controls.
  366          */
  367         if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
  368             (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
  369             (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
  370                 DPRINTF(("%s: IPsec outbound packet dropped due"
  371                         " to policy (check your sysctls)\n", __func__));
  372                 IPSEC_OSTAT(V_espstat.esps_pdrops, V_ahstat.ahs_pdrops,
  373                     V_ipcompstat.ipcomps_pdrops);
  374                 *error = EHOSTUNREACH;
  375                 goto bad;
  376         }
  377 
  378         /*
  379          * Sanity check the SA contents for the caller
  380          * before they invoke the xform output method.
  381          */
  382         if (sav->tdb_xform == NULL) {
  383                 DPRINTF(("%s: no transform for SA\n", __func__));
  384                 IPSEC_OSTAT(V_espstat.esps_noxform, V_ahstat.ahs_noxform,
  385                     V_ipcompstat.ipcomps_noxform);
  386                 *error = EHOSTUNREACH;
  387                 goto bad;
  388         }
  389         return isr;
  390 bad:
  391         IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
  392         IPSECREQUEST_UNLOCK(isr);
  393         return NULL;
  394 #undef IPSEC_OSTAT
  395 }
  396 
  397 #ifdef INET
  398 /*
  399  * IPsec output logic for IPv4.
  400  */
  401 int
  402 ipsec4_process_packet(
  403         struct mbuf *m,
  404         struct ipsecrequest *isr,
  405         int flags,
  406         int tunalready)
  407 {
  408         struct secasindex saidx;
  409         struct secasvar *sav;
  410         struct ip *ip;
  411         int error, i, off;
  412 
  413         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  414         IPSEC_ASSERT(isr != NULL, ("null isr"));
  415 
  416         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  417 
  418         isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
  419         if (isr == NULL) {
  420                 if (error != 0)
  421                         goto bad;
  422                 return EJUSTRETURN;
  423         }
  424 
  425         sav = isr->sav;
  426 
  427 #ifdef DEV_ENC
  428         encif->if_opackets++;
  429         encif->if_obytes += m->m_pkthdr.len;
  430 
  431         /* pass the mbuf to enc0 for bpf processing */
  432         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_BEFORE);
  433         /* pass the mbuf to enc0 for packet filtering */
  434         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  435                 goto bad;
  436 #endif
  437 
  438         if (!tunalready) {
  439                 union sockaddr_union *dst = &sav->sah->saidx.dst;
  440                 int setdf;
  441 
  442                 /*
  443                  * Collect IP_DF state from the outer header.
  444                  */
  445                 if (dst->sa.sa_family == AF_INET) {
  446                         if (m->m_len < sizeof (struct ip) &&
  447                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  448                                 error = ENOBUFS;
  449                                 goto bad;
  450                         }
  451                         ip = mtod(m, struct ip *);
  452                         /* Honor system-wide control of how to handle IP_DF */
  453                         switch (V_ip4_ipsec_dfbit) {
  454                         case 0:                 /* clear in outer header */
  455                         case 1:                 /* set in outer header */
  456                                 setdf = V_ip4_ipsec_dfbit;
  457                                 break;
  458                         default:                /* propagate to outer header */
  459                                 setdf = ntohs(ip->ip_off & IP_DF);
  460                                 break;
  461                         }
  462                 } else {
  463                         ip = NULL;              /* keep compiler happy */
  464                         setdf = 0;
  465                 }
  466                 /* Do the appropriate encapsulation, if necessary */
  467                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
  468                     dst->sa.sa_family != AF_INET ||         /* PF mismatch */
  469 #if 0
  470                     (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
  471                     sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
  472 #endif
  473                     (dst->sa.sa_family == AF_INET &&        /* Proxy */
  474                      dst->sin.sin_addr.s_addr != INADDR_ANY &&
  475                      dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
  476                         struct mbuf *mp;
  477 
  478                         /* Fix IPv4 header checksum and length */
  479                         if (m->m_len < sizeof (struct ip) &&
  480                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  481                                 error = ENOBUFS;
  482                                 goto bad;
  483                         }
  484                         ip = mtod(m, struct ip *);
  485                         ip->ip_len = htons(m->m_pkthdr.len);
  486                         ip->ip_sum = 0;
  487 #ifdef _IP_VHL
  488                         if (ip->ip_vhl == IP_VHL_BORING)
  489                                 ip->ip_sum = in_cksum_hdr(ip);
  490                         else
  491                                 ip->ip_sum = in_cksum(m,
  492                                         _IP_VHL_HL(ip->ip_vhl) << 2);
  493 #else
  494                         ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  495 #endif
  496 
  497                         /* Encapsulate the packet */
  498                         error = ipip_output(m, isr, &mp, 0, 0);
  499                         if (mp == NULL && !error) {
  500                                 /* Should never happen. */
  501                                 DPRINTF(("%s: ipip_output returns no mbuf and "
  502                                         "no error!", __func__));
  503                                 error = EFAULT;
  504                         }
  505                         if (error) {
  506                                 if (mp) {
  507                                         /* XXX: Should never happen! */
  508                                         m_freem(mp);
  509                                 }
  510                                 m = NULL; /* ipip_output() already freed it */
  511                                 goto bad;
  512                         }
  513                         m = mp, mp = NULL;
  514                         /*
  515                          * ipip_output clears IP_DF in the new header.  If
  516                          * we need to propagate IP_DF from the outer header,
  517                          * then we have to do it here.
  518                          *
  519                          * XXX shouldn't assume what ipip_output does.
  520                          */
  521                         if (dst->sa.sa_family == AF_INET && setdf) {
  522                                 if (m->m_len < sizeof (struct ip) &&
  523                                     (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  524                                         error = ENOBUFS;
  525                                         goto bad;
  526                                 }
  527                                 ip = mtod(m, struct ip *);
  528                                 ip->ip_off = ntohs(ip->ip_off);
  529                                 ip->ip_off |= IP_DF;
  530                                 ip->ip_off = htons(ip->ip_off);
  531                         }
  532                 }
  533         }
  534 
  535 #ifdef DEV_ENC
  536         /* pass the mbuf to enc0 for bpf processing */
  537         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_AFTER);
  538         /* pass the mbuf to enc0 for packet filtering */
  539         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  540                 goto bad;
  541 #endif
  542 
  543         /*
  544          * Dispatch to the appropriate IPsec transform logic.  The
  545          * packet will be returned for transmission after crypto
  546          * processing, etc. are completed.  For encapsulation we
  547          * bypass this call because of the explicit call done above
  548          * (necessary to deal with IP_DF handling for IPv4).
  549          *
  550          * NB: m & sav are ``passed to caller'' who's reponsible for
  551          *     for reclaiming their resources.
  552          */
  553         if (sav->tdb_xform->xf_type != XF_IP4) {
  554                 ip = mtod(m, struct ip *);
  555                 i = ip->ip_hl << 2;
  556                 off = offsetof(struct ip, ip_p);
  557                 error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
  558         } else {
  559                 error = ipsec_process_done(m, isr);
  560         }
  561         IPSECREQUEST_UNLOCK(isr);
  562         return error;
  563 bad:
  564         if (isr)
  565                 IPSECREQUEST_UNLOCK(isr);
  566         if (m)
  567                 m_freem(m);
  568         return error;
  569 }
  570 #endif
  571 
  572 #ifdef INET6
  573 /*
  574  * Chop IP6 header from the payload.
  575  */
  576 static struct mbuf *
  577 ipsec6_splithdr(struct mbuf *m)
  578 {
  579         struct mbuf *mh;
  580         struct ip6_hdr *ip6;
  581         int hlen;
  582 
  583         IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
  584                 ("first mbuf too short, len %u", m->m_len));
  585         ip6 = mtod(m, struct ip6_hdr *);
  586         hlen = sizeof(struct ip6_hdr);
  587         if (m->m_len > hlen) {
  588                 MGETHDR(mh, M_DONTWAIT, MT_DATA);
  589                 if (!mh) {
  590                         m_freem(m);
  591                         return NULL;
  592                 }
  593                 M_MOVE_PKTHDR(mh, m);
  594                 MH_ALIGN(mh, hlen);
  595                 m->m_len -= hlen;
  596                 m->m_data += hlen;
  597                 mh->m_next = m;
  598                 m = mh;
  599                 m->m_len = hlen;
  600                 bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
  601         } else if (m->m_len < hlen) {
  602                 m = m_pullup(m, hlen);
  603                 if (!m)
  604                         return NULL;
  605         }
  606         return m;
  607 }
  608 
  609 /*
  610  * IPsec output logic for IPv6, transport mode.
  611  */
  612 int
  613 ipsec6_output_trans(
  614         struct ipsec_output_state *state,
  615         u_char *nexthdrp,
  616         struct mbuf *mprev,
  617         struct secpolicy *sp,
  618         int flags,
  619         int *tun)
  620 {
  621         struct ipsecrequest *isr;
  622         struct secasindex saidx;
  623         int error = 0;
  624         struct mbuf *m;
  625 
  626         IPSEC_ASSERT(state != NULL, ("null state"));
  627         IPSEC_ASSERT(state->m != NULL, ("null m"));
  628         IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
  629         IPSEC_ASSERT(mprev != NULL, ("null mprev"));
  630         IPSEC_ASSERT(sp != NULL, ("null sp"));
  631         IPSEC_ASSERT(tun != NULL, ("null tun"));
  632 
  633         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  634                 printf("%s: applied SP\n", __func__);
  635                 kdebug_secpolicy(sp));
  636 
  637         isr = sp->req;
  638         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  639                 /* the rest will be handled by ipsec6_output_tunnel() */
  640                 *tun = 1;               /* need tunnel-mode processing */
  641                 return 0;
  642         }
  643 
  644         *tun = 0;
  645         m = state->m;
  646 
  647         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  648         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  649         if (isr == NULL) {
  650                 if (error != 0) {
  651 #ifdef notdef
  652                         /* XXX should notification be done for all errors ? */
  653                         /*
  654                          * Notify the fact that the packet is discarded
  655                          * to ourselves. I believe this is better than
  656                          * just silently discarding. (jinmei@kame.net)
  657                          * XXX: should we restrict the error to TCP packets?
  658                          * XXX: should we directly notify sockets via
  659                          *      pfctlinputs?
  660                          */
  661                         icmp6_error(m, ICMP6_DST_UNREACH,
  662                                     ICMP6_DST_UNREACH_ADMIN, 0);
  663                         m = NULL;       /* NB: icmp6_error frees mbuf */
  664 #endif
  665                         goto bad;
  666                 }
  667                 return EJUSTRETURN;
  668         }
  669 
  670         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  671                                                   sizeof (struct ip6_hdr),
  672                                                   offsetof(struct ip6_hdr, 
  673                                                            ip6_nxt));
  674         IPSECREQUEST_UNLOCK(isr);
  675         return error;
  676 bad:
  677         if (isr)
  678                 IPSECREQUEST_UNLOCK(isr);
  679         if (m)
  680                 m_freem(m);
  681         state->m = NULL;
  682         return error;
  683 }
  684 
  685 static int
  686 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
  687 {
  688         struct ip6_hdr *oip6;
  689         struct ip6_hdr *ip6;
  690         size_t plen;
  691 
  692         /* can't tunnel between different AFs */
  693         if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
  694             sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
  695                 m_freem(m);
  696                 return EINVAL;
  697         }
  698         IPSEC_ASSERT(m->m_len == sizeof (struct ip6_hdr),
  699                 ("mbuf wrong size; len %u", m->m_len));
  700 
  701 
  702         /*
  703          * grow the mbuf to accomodate the new IPv6 header.
  704          */
  705         plen = m->m_pkthdr.len;
  706         if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
  707                 struct mbuf *n;
  708                 MGET(n, M_DONTWAIT, MT_DATA);
  709                 if (!n) {
  710                         m_freem(m);
  711                         return ENOBUFS;
  712                 }
  713                 n->m_len = sizeof(struct ip6_hdr);
  714                 n->m_next = m->m_next;
  715                 m->m_next = n;
  716                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  717                 oip6 = mtod(n, struct ip6_hdr *);
  718         } else {
  719                 m->m_next->m_len += sizeof(struct ip6_hdr);
  720                 m->m_next->m_data -= sizeof(struct ip6_hdr);
  721                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  722                 oip6 = mtod(m->m_next, struct ip6_hdr *);
  723         }
  724         ip6 = mtod(m, struct ip6_hdr *);
  725         bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
  726 
  727         /* Fake link-local scope-class addresses */
  728         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
  729                 oip6->ip6_src.s6_addr16[1] = 0;
  730         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
  731                 oip6->ip6_dst.s6_addr16[1] = 0;
  732 
  733         /* construct new IPv6 header. see RFC 2401 5.1.2.2 */
  734         /* ECN consideration. */
  735         ip6_ecn_ingress(V_ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
  736         if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
  737                 ip6->ip6_plen = htons(plen);
  738         else {
  739                 /* ip6->ip6_plen will be updated in ip6_output() */
  740         }
  741         ip6->ip6_nxt = IPPROTO_IPV6;
  742         ip6->ip6_src = sav->sah->saidx.src.sin6.sin6_addr;
  743         ip6->ip6_dst = sav->sah->saidx.dst.sin6.sin6_addr;
  744         ip6->ip6_hlim = IPV6_DEFHLIM;
  745 
  746         /* XXX Should ip6_src be updated later ? */
  747 
  748         return 0;
  749 }
  750 
  751 /*
  752  * IPsec output logic for IPv6, tunnel mode.
  753  */
  754 int
  755 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
  756 {
  757         struct ip6_hdr *ip6;
  758         struct ipsecrequest *isr;
  759         struct secasindex saidx;
  760         int error;
  761         struct sockaddr_in6 *dst6;
  762         struct mbuf *m;
  763 
  764         IPSEC_ASSERT(state != NULL, ("null state"));
  765         IPSEC_ASSERT(state->m != NULL, ("null m"));
  766         IPSEC_ASSERT(sp != NULL, ("null sp"));
  767 
  768         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  769                 printf("%s: applied SP\n", __func__);
  770                 kdebug_secpolicy(sp));
  771 
  772         m = state->m;
  773         /*
  774          * transport mode ipsec (before the 1st tunnel mode) is already
  775          * processed by ipsec6_output_trans().
  776          */
  777         for (isr = sp->req; isr; isr = isr->next) {
  778                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  779                         break;
  780         }
  781 
  782         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  783         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  784         if (isr == NULL) {
  785                 if (error != 0)
  786                         goto bad;
  787                 return EJUSTRETURN; 
  788         }
  789 
  790 #ifdef DEV_ENC
  791         encif->if_opackets++;
  792         encif->if_obytes += m->m_pkthdr.len;
  793 
  794         /* pass the mbuf to enc0 for bpf processing */
  795         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_BEFORE);
  796         /* pass the mbuf to enc0 for packet filtering */
  797         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  798                 goto bad;
  799 #endif
  800 
  801         /*
  802          * There may be the case that SA status will be changed when
  803          * we are refering to one. So calling splsoftnet().
  804          */
  805         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  806                 /*
  807                  * build IPsec tunnel.
  808                  */
  809                 /* XXX should be processed with other familiy */
  810                 if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
  811                         ipseclog((LOG_ERR, "%s: family mismatched between "
  812                             "inner and outer, spi=%u\n", __func__,
  813                             ntohl(isr->sav->spi)));
  814                         V_ipsec6stat.ips_out_inval++;
  815                         error = EAFNOSUPPORT;
  816                         goto bad;
  817                 }
  818 
  819                 m = ipsec6_splithdr(m);
  820                 if (!m) {
  821                         V_ipsec6stat.ips_out_nomem++;
  822                         error = ENOMEM;
  823                         goto bad;
  824                 }
  825                 error = ipsec6_encapsulate(m, isr->sav);
  826                 if (error) {
  827                         m = NULL;
  828                         goto bad;
  829                 }
  830                 ip6 = mtod(m, struct ip6_hdr *);
  831 
  832                 state->ro =
  833                     (struct route *)&isr->sav->sah->route_cache.sin6_route;
  834                 state->dst = (struct sockaddr *)&state->ro->ro_dst;
  835                 dst6 = (struct sockaddr_in6 *)state->dst;
  836                 if (state->ro->ro_rt
  837                  && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
  838                   || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
  839                         RTFREE(state->ro->ro_rt);
  840                         state->ro->ro_rt = NULL;
  841                 }
  842                 if (state->ro->ro_rt == NULL) {
  843                         bzero(dst6, sizeof(*dst6));
  844                         dst6->sin6_family = AF_INET6;
  845                         dst6->sin6_len = sizeof(*dst6);
  846                         dst6->sin6_addr = ip6->ip6_dst;
  847                         rtalloc(state->ro);
  848                 }
  849                 if (state->ro->ro_rt == NULL) {
  850                         V_ip6stat.ip6s_noroute++;
  851                         V_ipsec6stat.ips_out_noroute++;
  852                         error = EHOSTUNREACH;
  853                         goto bad;
  854                 }
  855 
  856                 /* adjust state->dst if tunnel endpoint is offlink */
  857                 if (state->ro->ro_rt->rt_flags & RTF_GATEWAY)
  858                         state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
  859         }
  860 
  861         m = ipsec6_splithdr(m);
  862         if (!m) {
  863                 V_ipsec6stat.ips_out_nomem++;
  864                 error = ENOMEM;
  865                 goto bad;
  866         }
  867         ip6 = mtod(m, struct ip6_hdr *);
  868 
  869 #ifdef DEV_ENC
  870         /* pass the mbuf to enc0 for bpf processing */
  871         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_AFTER);
  872         /* pass the mbuf to enc0 for packet filtering */
  873         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  874                 goto bad;
  875 #endif
  876 
  877         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  878                 sizeof (struct ip6_hdr),
  879                 offsetof(struct ip6_hdr, ip6_nxt));
  880         IPSECREQUEST_UNLOCK(isr);
  881         return error;
  882 bad:
  883         if (isr)
  884                 IPSECREQUEST_UNLOCK(isr);
  885         if (m)
  886                 m_freem(m);
  887         state->m = NULL;
  888         return error;
  889 }
  890 #endif /*INET6*/

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