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: stable/8/sys/netipsec/ipsec_output.c 232552 2012-03-05 17:33:01Z 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         return (error);
  251 }
  252 
  253 static struct ipsecrequest *
  254 ipsec_nextisr(
  255         struct mbuf *m,
  256         struct ipsecrequest *isr,
  257         int af,
  258         struct secasindex *saidx,
  259         int *error
  260 )
  261 {
  262 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
  263                             isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
  264         struct secasvar *sav;
  265 
  266         IPSECREQUEST_LOCK_ASSERT(isr);
  267 
  268         IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
  269                 ("invalid address family %u", af));
  270 again:
  271         /*
  272          * Craft SA index to search for proper SA.  Note that
  273          * we only fillin unspecified SA peers for transport
  274          * mode; for tunnel mode they must already be filled in.
  275          */
  276         *saidx = isr->saidx;
  277         if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
  278                 /* Fillin unspecified SA peers only for transport mode */
  279                 if (af == AF_INET) {
  280                         struct sockaddr_in *sin;
  281                         struct ip *ip = mtod(m, struct ip *);
  282 
  283                         if (saidx->src.sa.sa_len == 0) {
  284                                 sin = &saidx->src.sin;
  285                                 sin->sin_len = sizeof(*sin);
  286                                 sin->sin_family = AF_INET;
  287                                 sin->sin_port = IPSEC_PORT_ANY;
  288                                 sin->sin_addr = ip->ip_src;
  289                         }
  290                         if (saidx->dst.sa.sa_len == 0) {
  291                                 sin = &saidx->dst.sin;
  292                                 sin->sin_len = sizeof(*sin);
  293                                 sin->sin_family = AF_INET;
  294                                 sin->sin_port = IPSEC_PORT_ANY;
  295                                 sin->sin_addr = ip->ip_dst;
  296                         }
  297                 } else {
  298                         struct sockaddr_in6 *sin6;
  299                         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  300 
  301                         if (saidx->src.sin6.sin6_len == 0) {
  302                                 sin6 = (struct sockaddr_in6 *)&saidx->src;
  303                                 sin6->sin6_len = sizeof(*sin6);
  304                                 sin6->sin6_family = AF_INET6;
  305                                 sin6->sin6_port = IPSEC_PORT_ANY;
  306                                 sin6->sin6_addr = ip6->ip6_src;
  307                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
  308                                         /* fix scope id for comparing SPD */
  309                                         sin6->sin6_addr.s6_addr16[1] = 0;
  310                                         sin6->sin6_scope_id =
  311                                             ntohs(ip6->ip6_src.s6_addr16[1]);
  312                                 }
  313                         }
  314                         if (saidx->dst.sin6.sin6_len == 0) {
  315                                 sin6 = (struct sockaddr_in6 *)&saidx->dst;
  316                                 sin6->sin6_len = sizeof(*sin6);
  317                                 sin6->sin6_family = AF_INET6;
  318                                 sin6->sin6_port = IPSEC_PORT_ANY;
  319                                 sin6->sin6_addr = ip6->ip6_dst;
  320                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
  321                                         /* fix scope id for comparing SPD */
  322                                         sin6->sin6_addr.s6_addr16[1] = 0;
  323                                         sin6->sin6_scope_id =
  324                                             ntohs(ip6->ip6_dst.s6_addr16[1]);
  325                                 }
  326                         }
  327                 }
  328         }
  329 
  330         /*
  331          * Lookup SA and validate it.
  332          */
  333         *error = key_checkrequest(isr, saidx);
  334         if (*error != 0) {
  335                 /*
  336                  * IPsec processing is required, but no SA found.
  337                  * I assume that key_acquire() had been called
  338                  * to get/establish the SA. Here I discard
  339                  * this packet because it is responsibility for
  340                  * upper layer to retransmit the packet.
  341                  */
  342                 V_ipsec4stat.ips_out_nosa++;
  343                 goto bad;
  344         }
  345         sav = isr->sav;
  346         if (sav == NULL) {
  347                 IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
  348                         ("no SA found, but required; level %u",
  349                         ipsec_get_reqlevel(isr)));
  350                 IPSECREQUEST_UNLOCK(isr);
  351                 isr = isr->next;
  352                 /*
  353                  * If isr is NULL, we found a 'use' policy w/o SA.
  354                  * Return w/o error and w/o isr so we can drop out
  355                  * and continue w/o IPsec processing.
  356                  */
  357                 if (isr == NULL)
  358                         return isr;
  359                 IPSECREQUEST_LOCK(isr);
  360                 goto again;
  361         }
  362 
  363         /*
  364          * Check system global policy controls.
  365          */
  366         if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
  367             (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
  368             (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
  369                 DPRINTF(("%s: IPsec outbound packet dropped due"
  370                         " to policy (check your sysctls)\n", __func__));
  371                 IPSEC_OSTAT(V_espstat.esps_pdrops, V_ahstat.ahs_pdrops,
  372                     V_ipcompstat.ipcomps_pdrops);
  373                 *error = EHOSTUNREACH;
  374                 goto bad;
  375         }
  376 
  377         /*
  378          * Sanity check the SA contents for the caller
  379          * before they invoke the xform output method.
  380          */
  381         if (sav->tdb_xform == NULL) {
  382                 DPRINTF(("%s: no transform for SA\n", __func__));
  383                 IPSEC_OSTAT(V_espstat.esps_noxform, V_ahstat.ahs_noxform,
  384                     V_ipcompstat.ipcomps_noxform);
  385                 *error = EHOSTUNREACH;
  386                 goto bad;
  387         }
  388         return isr;
  389 bad:
  390         IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
  391         IPSECREQUEST_UNLOCK(isr);
  392         return NULL;
  393 #undef IPSEC_OSTAT
  394 }
  395 
  396 #ifdef INET
  397 /*
  398  * IPsec output logic for IPv4.
  399  */
  400 int
  401 ipsec4_process_packet(
  402         struct mbuf *m,
  403         struct ipsecrequest *isr,
  404         int flags,
  405         int tunalready)
  406 {
  407         struct secasindex saidx;
  408         struct secasvar *sav;
  409         struct ip *ip;
  410         int error, i, off;
  411 
  412         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  413         IPSEC_ASSERT(isr != NULL, ("null isr"));
  414 
  415         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  416 
  417         isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
  418         if (isr == NULL) {
  419                 if (error != 0)
  420                         goto bad;
  421                 return EJUSTRETURN;
  422         }
  423 
  424         sav = isr->sav;
  425 
  426 #ifdef DEV_ENC
  427         encif->if_opackets++;
  428         encif->if_obytes += m->m_pkthdr.len;
  429 
  430         /* pass the mbuf to enc0 for bpf processing */
  431         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_BEFORE);
  432         /* pass the mbuf to enc0 for packet filtering */
  433         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  434                 goto bad;
  435 #endif
  436 
  437         if (!tunalready) {
  438                 union sockaddr_union *dst = &sav->sah->saidx.dst;
  439                 int setdf;
  440 
  441                 /*
  442                  * Collect IP_DF state from the outer header.
  443                  */
  444                 if (dst->sa.sa_family == AF_INET) {
  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                         /* Honor system-wide control of how to handle IP_DF */
  452                         switch (V_ip4_ipsec_dfbit) {
  453                         case 0:                 /* clear in outer header */
  454                         case 1:                 /* set in outer header */
  455                                 setdf = V_ip4_ipsec_dfbit;
  456                                 break;
  457                         default:                /* propagate to outer header */
  458                                 setdf = ntohs(ip->ip_off & IP_DF);
  459                                 break;
  460                         }
  461                 } else {
  462                         ip = NULL;              /* keep compiler happy */
  463                         setdf = 0;
  464                 }
  465                 /* Do the appropriate encapsulation, if necessary */
  466                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
  467                     dst->sa.sa_family != AF_INET ||         /* PF mismatch */
  468 #if 0
  469                     (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
  470                     sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
  471 #endif
  472                     (dst->sa.sa_family == AF_INET &&        /* Proxy */
  473                      dst->sin.sin_addr.s_addr != INADDR_ANY &&
  474                      dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
  475                         struct mbuf *mp;
  476 
  477                         /* Fix IPv4 header checksum and length */
  478                         if (m->m_len < sizeof (struct ip) &&
  479                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  480                                 error = ENOBUFS;
  481                                 goto bad;
  482                         }
  483                         ip = mtod(m, struct ip *);
  484                         ip->ip_len = htons(m->m_pkthdr.len);
  485                         ip->ip_sum = 0;
  486 #ifdef _IP_VHL
  487                         if (ip->ip_vhl == IP_VHL_BORING)
  488                                 ip->ip_sum = in_cksum_hdr(ip);
  489                         else
  490                                 ip->ip_sum = in_cksum(m,
  491                                         _IP_VHL_HL(ip->ip_vhl) << 2);
  492 #else
  493                         ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  494 #endif
  495 
  496                         /* Encapsulate the packet */
  497                         error = ipip_output(m, isr, &mp, 0, 0);
  498                         if (mp == NULL && !error) {
  499                                 /* Should never happen. */
  500                                 DPRINTF(("%s: ipip_output returns no mbuf and "
  501                                         "no error!", __func__));
  502                                 error = EFAULT;
  503                         }
  504                         if (error) {
  505                                 if (mp) {
  506                                         /* XXX: Should never happen! */
  507                                         m_freem(mp);
  508                                 }
  509                                 m = NULL; /* ipip_output() already freed it */
  510                                 goto bad;
  511                         }
  512                         m = mp, mp = NULL;
  513                         /*
  514                          * ipip_output clears IP_DF in the new header.  If
  515                          * we need to propagate IP_DF from the outer header,
  516                          * then we have to do it here.
  517                          *
  518                          * XXX shouldn't assume what ipip_output does.
  519                          */
  520                         if (dst->sa.sa_family == AF_INET && setdf) {
  521                                 if (m->m_len < sizeof (struct ip) &&
  522                                     (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  523                                         error = ENOBUFS;
  524                                         goto bad;
  525                                 }
  526                                 ip = mtod(m, struct ip *);
  527                                 ip->ip_off = ntohs(ip->ip_off);
  528                                 ip->ip_off |= IP_DF;
  529                                 ip->ip_off = htons(ip->ip_off);
  530                         }
  531                 }
  532         }
  533 
  534 #ifdef DEV_ENC
  535         /* pass the mbuf to enc0 for bpf processing */
  536         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_AFTER);
  537         /* pass the mbuf to enc0 for packet filtering */
  538         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  539                 goto bad;
  540 #endif
  541 
  542         /*
  543          * Dispatch to the appropriate IPsec transform logic.  The
  544          * packet will be returned for transmission after crypto
  545          * processing, etc. are completed.  For encapsulation we
  546          * bypass this call because of the explicit call done above
  547          * (necessary to deal with IP_DF handling for IPv4).
  548          *
  549          * NB: m & sav are ``passed to caller'' who's reponsible for
  550          *     for reclaiming their resources.
  551          */
  552         if (sav->tdb_xform->xf_type != XF_IP4) {
  553                 ip = mtod(m, struct ip *);
  554                 i = ip->ip_hl << 2;
  555                 off = offsetof(struct ip, ip_p);
  556                 error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
  557         } else {
  558                 error = ipsec_process_done(m, isr);
  559         }
  560         IPSECREQUEST_UNLOCK(isr);
  561         return error;
  562 bad:
  563         if (isr)
  564                 IPSECREQUEST_UNLOCK(isr);
  565         if (m)
  566                 m_freem(m);
  567         return error;
  568 }
  569 #endif
  570 
  571 #ifdef INET6
  572 /*
  573  * Chop IP6 header from the payload.
  574  */
  575 static struct mbuf *
  576 ipsec6_splithdr(struct mbuf *m)
  577 {
  578         struct mbuf *mh;
  579         struct ip6_hdr *ip6;
  580         int hlen;
  581 
  582         IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
  583                 ("first mbuf too short, len %u", m->m_len));
  584         ip6 = mtod(m, struct ip6_hdr *);
  585         hlen = sizeof(struct ip6_hdr);
  586         if (m->m_len > hlen) {
  587                 MGETHDR(mh, M_DONTWAIT, MT_DATA);
  588                 if (!mh) {
  589                         m_freem(m);
  590                         return NULL;
  591                 }
  592                 M_MOVE_PKTHDR(mh, m);
  593                 MH_ALIGN(mh, hlen);
  594                 m->m_len -= hlen;
  595                 m->m_data += hlen;
  596                 mh->m_next = m;
  597                 m = mh;
  598                 m->m_len = hlen;
  599                 bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
  600         } else if (m->m_len < hlen) {
  601                 m = m_pullup(m, hlen);
  602                 if (!m)
  603                         return NULL;
  604         }
  605         return m;
  606 }
  607 
  608 /*
  609  * IPsec output logic for IPv6, transport mode.
  610  */
  611 int
  612 ipsec6_output_trans(
  613         struct ipsec_output_state *state,
  614         u_char *nexthdrp,
  615         struct mbuf *mprev,
  616         struct secpolicy *sp,
  617         int flags,
  618         int *tun)
  619 {
  620         struct ipsecrequest *isr;
  621         struct secasindex saidx;
  622         int error = 0;
  623         struct mbuf *m;
  624 
  625         IPSEC_ASSERT(state != NULL, ("null state"));
  626         IPSEC_ASSERT(state->m != NULL, ("null m"));
  627         IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
  628         IPSEC_ASSERT(mprev != NULL, ("null mprev"));
  629         IPSEC_ASSERT(sp != NULL, ("null sp"));
  630         IPSEC_ASSERT(tun != NULL, ("null tun"));
  631 
  632         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  633                 printf("%s: applied SP\n", __func__);
  634                 kdebug_secpolicy(sp));
  635 
  636         isr = sp->req;
  637         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  638                 /* the rest will be handled by ipsec6_output_tunnel() */
  639                 *tun = 1;               /* need tunnel-mode processing */
  640                 return 0;
  641         }
  642 
  643         *tun = 0;
  644         m = state->m;
  645 
  646         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  647         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  648         if (isr == NULL) {
  649                 if (error != 0) {
  650 #ifdef notdef
  651                         /* XXX should notification be done for all errors ? */
  652                         /*
  653                          * Notify the fact that the packet is discarded
  654                          * to ourselves. I believe this is better than
  655                          * just silently discarding. (jinmei@kame.net)
  656                          * XXX: should we restrict the error to TCP packets?
  657                          * XXX: should we directly notify sockets via
  658                          *      pfctlinputs?
  659                          */
  660                         icmp6_error(m, ICMP6_DST_UNREACH,
  661                                     ICMP6_DST_UNREACH_ADMIN, 0);
  662                         m = NULL;       /* NB: icmp6_error frees mbuf */
  663 #endif
  664                         goto bad;
  665                 }
  666                 return EJUSTRETURN;
  667         }
  668 
  669         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  670                                                   sizeof (struct ip6_hdr),
  671                                                   offsetof(struct ip6_hdr, 
  672                                                            ip6_nxt));
  673         IPSECREQUEST_UNLOCK(isr);
  674         return error;
  675 bad:
  676         if (isr)
  677                 IPSECREQUEST_UNLOCK(isr);
  678         if (m)
  679                 m_freem(m);
  680         state->m = NULL;
  681         return error;
  682 }
  683 
  684 static int
  685 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
  686 {
  687         struct ip6_hdr *oip6;
  688         struct ip6_hdr *ip6;
  689         size_t plen;
  690 
  691         /* can't tunnel between different AFs */
  692         if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
  693             sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
  694                 m_freem(m);
  695                 return EINVAL;
  696         }
  697         IPSEC_ASSERT(m->m_len == sizeof (struct ip6_hdr),
  698                 ("mbuf wrong size; len %u", m->m_len));
  699 
  700 
  701         /*
  702          * grow the mbuf to accomodate the new IPv6 header.
  703          */
  704         plen = m->m_pkthdr.len;
  705         if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
  706                 struct mbuf *n;
  707                 MGET(n, M_DONTWAIT, MT_DATA);
  708                 if (!n) {
  709                         m_freem(m);
  710                         return ENOBUFS;
  711                 }
  712                 n->m_len = sizeof(struct ip6_hdr);
  713                 n->m_next = m->m_next;
  714                 m->m_next = n;
  715                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  716                 oip6 = mtod(n, struct ip6_hdr *);
  717         } else {
  718                 m->m_next->m_len += sizeof(struct ip6_hdr);
  719                 m->m_next->m_data -= sizeof(struct ip6_hdr);
  720                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  721                 oip6 = mtod(m->m_next, struct ip6_hdr *);
  722         }
  723         ip6 = mtod(m, struct ip6_hdr *);
  724         bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
  725 
  726         /* Fake link-local scope-class addresses */
  727         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
  728                 oip6->ip6_src.s6_addr16[1] = 0;
  729         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
  730                 oip6->ip6_dst.s6_addr16[1] = 0;
  731 
  732         /* construct new IPv6 header. see RFC 2401 5.1.2.2 */
  733         /* ECN consideration. */
  734         ip6_ecn_ingress(V_ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
  735         if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
  736                 ip6->ip6_plen = htons(plen);
  737         else {
  738                 /* ip6->ip6_plen will be updated in ip6_output() */
  739         }
  740         ip6->ip6_nxt = IPPROTO_IPV6;
  741         ip6->ip6_src = sav->sah->saidx.src.sin6.sin6_addr;
  742         ip6->ip6_dst = sav->sah->saidx.dst.sin6.sin6_addr;
  743         ip6->ip6_hlim = IPV6_DEFHLIM;
  744 
  745         /* XXX Should ip6_src be updated later ? */
  746 
  747         return 0;
  748 }
  749 
  750 /*
  751  * IPsec output logic for IPv6, tunnel mode.
  752  */
  753 int
  754 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
  755 {
  756         struct ip6_hdr *ip6;
  757         struct ipsecrequest *isr;
  758         struct secasindex saidx;
  759         int error;
  760         struct sockaddr_in6 *dst6;
  761         struct mbuf *m;
  762 
  763         IPSEC_ASSERT(state != NULL, ("null state"));
  764         IPSEC_ASSERT(state->m != NULL, ("null m"));
  765         IPSEC_ASSERT(sp != NULL, ("null sp"));
  766 
  767         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  768                 printf("%s: applied SP\n", __func__);
  769                 kdebug_secpolicy(sp));
  770 
  771         m = state->m;
  772         /*
  773          * transport mode ipsec (before the 1st tunnel mode) is already
  774          * processed by ipsec6_output_trans().
  775          */
  776         for (isr = sp->req; isr; isr = isr->next) {
  777                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  778                         break;
  779         }
  780 
  781         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  782         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  783         if (isr == NULL) {
  784                 if (error != 0)
  785                         goto bad;
  786                 return EJUSTRETURN; 
  787         }
  788 
  789 #ifdef DEV_ENC
  790         encif->if_opackets++;
  791         encif->if_obytes += m->m_pkthdr.len;
  792 
  793         /* pass the mbuf to enc0 for bpf processing */
  794         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_BEFORE);
  795         /* pass the mbuf to enc0 for packet filtering */
  796         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  797                 goto bad;
  798 #endif
  799 
  800         /*
  801          * There may be the case that SA status will be changed when
  802          * we are refering to one. So calling splsoftnet().
  803          */
  804         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  805                 /*
  806                  * build IPsec tunnel.
  807                  */
  808                 /* XXX should be processed with other familiy */
  809                 if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
  810                         ipseclog((LOG_ERR, "%s: family mismatched between "
  811                             "inner and outer, spi=%u\n", __func__,
  812                             ntohl(isr->sav->spi)));
  813                         V_ipsec6stat.ips_out_inval++;
  814                         error = EAFNOSUPPORT;
  815                         goto bad;
  816                 }
  817 
  818                 m = ipsec6_splithdr(m);
  819                 if (!m) {
  820                         V_ipsec6stat.ips_out_nomem++;
  821                         error = ENOMEM;
  822                         goto bad;
  823                 }
  824                 error = ipsec6_encapsulate(m, isr->sav);
  825                 if (error) {
  826                         m = NULL;
  827                         goto bad;
  828                 }
  829                 ip6 = mtod(m, struct ip6_hdr *);
  830 
  831                 state->ro =
  832                     (struct route *)&isr->sav->sah->route_cache.sin6_route;
  833                 state->dst = (struct sockaddr *)&state->ro->ro_dst;
  834                 dst6 = (struct sockaddr_in6 *)state->dst;
  835                 if (state->ro->ro_rt
  836                  && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
  837                   || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
  838                         RTFREE(state->ro->ro_rt);
  839                         state->ro->ro_rt = NULL;
  840                 }
  841                 if (state->ro->ro_rt == NULL) {
  842                         bzero(dst6, sizeof(*dst6));
  843                         dst6->sin6_family = AF_INET6;
  844                         dst6->sin6_len = sizeof(*dst6);
  845                         dst6->sin6_addr = ip6->ip6_dst;
  846                         rtalloc_ign_fib(state->ro, 0UL, M_GETFIB(m));
  847                 }
  848                 if (state->ro->ro_rt == NULL) {
  849                         V_ip6stat.ip6s_noroute++;
  850                         V_ipsec6stat.ips_out_noroute++;
  851                         error = EHOSTUNREACH;
  852                         goto bad;
  853                 }
  854 
  855                 /* adjust state->dst if tunnel endpoint is offlink */
  856                 if (state->ro->ro_rt->rt_flags & RTF_GATEWAY)
  857                         state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
  858         }
  859 
  860         m = ipsec6_splithdr(m);
  861         if (!m) {
  862                 V_ipsec6stat.ips_out_nomem++;
  863                 error = ENOMEM;
  864                 goto bad;
  865         }
  866         ip6 = mtod(m, struct ip6_hdr *);
  867 
  868 #ifdef DEV_ENC
  869         /* pass the mbuf to enc0 for bpf processing */
  870         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_AFTER);
  871         /* pass the mbuf to enc0 for packet filtering */
  872         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  873                 goto bad;
  874 #endif
  875 
  876         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  877                 sizeof (struct ip6_hdr),
  878                 offsetof(struct ip6_hdr, ip6_nxt));
  879         IPSECREQUEST_UNLOCK(isr);
  880         return error;
  881 bad:
  882         if (isr)
  883                 IPSECREQUEST_UNLOCK(isr);
  884         if (m)
  885                 m_freem(m);
  886         state->m = NULL;
  887         return error;
  888 }
  889 #endif /*INET6*/

Cache object: ad6082304dadfae851cda1aa4cecf687


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