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/9.0/sys/netipsec/ipsec_output.c 223637 2011-06-28 11:57:25Z 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                 sav = isr->next->sav;
  169                 saidx = &sav->sah->saidx;
  170                 switch (saidx->dst.sa.sa_family) {
  171 #ifdef INET
  172                 case AF_INET:
  173                         return ipsec4_process_packet(m, isr->next, 0, 0);
  174                         /* NOTREACHED */
  175 #endif
  176 #ifdef notyet
  177 #ifdef INET6
  178                 case AF_INET6:
  179                         /* XXX */
  180                         ipsec6_output_trans()
  181                         ipsec6_output_tunnel()
  182                         /* NOTREACHED */
  183 #endif /* INET6 */
  184 #endif
  185                 default:
  186                         DPRINTF(("%s: unknown protocol family %u\n", __func__,
  187                             saidx->dst.sa.sa_family));
  188                         error = ENXIO;
  189                         goto bad;
  190                 }
  191         }
  192         key_sa_recordxfer(sav, m);              /* record data transfer */
  193 
  194         m_addr_changed(m);
  195 
  196         /*
  197          * We're done with IPsec processing, transmit the packet using the
  198          * appropriate network protocol (IP or IPv6). SPD lookup will be
  199          * performed again there.
  200          */
  201         switch (saidx->dst.sa.sa_family) {
  202 #ifdef INET
  203         struct ip *ip;
  204         case AF_INET:
  205                 ip = mtod(m, struct ip *);
  206                 ip->ip_len = ntohs(ip->ip_len);
  207                 ip->ip_off = ntohs(ip->ip_off);
  208 
  209 #ifdef IPSEC_NAT_T
  210                 /*
  211                  * If NAT-T is enabled, now that all IPsec processing is done
  212                  * insert UDP encapsulation header after IP header.
  213                  */
  214                 if (sav->natt_type) {
  215 #ifdef _IP_VHL
  216                         const int hlen = IP_VHL_HL(ip->ip_vhl);
  217 #else
  218                         const int hlen = (ip->ip_hl << 2);
  219 #endif
  220                         int size, off;
  221                         struct mbuf *mi;
  222                         struct udphdr *udp;
  223 
  224                         size = sizeof(struct udphdr);
  225                         if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
  226                                 /*
  227                                  * draft-ietf-ipsec-nat-t-ike-0[01].txt and
  228                                  * draft-ietf-ipsec-udp-encaps-(00/)01.txt,
  229                                  * ignoring possible AH mode
  230                                  * non-IKE marker + non-ESP marker
  231                                  * from draft-ietf-ipsec-udp-encaps-00.txt.
  232                                  */
  233                                 size += sizeof(u_int64_t);
  234                         }
  235                         mi = m_makespace(m, hlen, size, &off);
  236                         if (mi == NULL) {
  237                                 DPRINTF(("%s: m_makespace for udphdr failed\n",
  238                                     __func__));
  239                                 error = ENOBUFS;
  240                                 goto bad;
  241                         }
  242 
  243                         udp = (struct udphdr *)(mtod(mi, caddr_t) + off);
  244                         if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
  245                                 udp->uh_sport = htons(UDP_ENCAP_ESPINUDP_PORT);
  246                         else
  247                                 udp->uh_sport =
  248                                         KEY_PORTFROMSADDR(&sav->sah->saidx.src);
  249                         udp->uh_dport = KEY_PORTFROMSADDR(&sav->sah->saidx.dst);
  250                         udp->uh_sum = 0;
  251                         udp->uh_ulen = htons(m->m_pkthdr.len - hlen);
  252                         ip->ip_len = m->m_pkthdr.len;
  253                         ip->ip_p = IPPROTO_UDP;
  254 
  255                         if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
  256                                 *(u_int64_t *)(udp + 1) = 0;
  257                 }
  258 #endif /* IPSEC_NAT_T */
  259 
  260                 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
  261 #endif /* INET */
  262 #ifdef INET6
  263         case AF_INET6:
  264                 /*
  265                  * We don't need massage, IPv6 header fields are always in
  266                  * net endian.
  267                  */
  268                 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
  269 #endif /* INET6 */
  270         }
  271         panic("ipsec_process_done");
  272 bad:
  273         m_freem(m);
  274         return (error);
  275 }
  276 
  277 static struct ipsecrequest *
  278 ipsec_nextisr(
  279         struct mbuf *m,
  280         struct ipsecrequest *isr,
  281         int af,
  282         struct secasindex *saidx,
  283         int *error
  284 )
  285 {
  286 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
  287                             isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
  288         struct secasvar *sav;
  289 
  290         IPSECREQUEST_LOCK_ASSERT(isr);
  291 
  292         IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
  293                 ("invalid address family %u", af));
  294 again:
  295         /*
  296          * Craft SA index to search for proper SA.  Note that
  297          * we only fillin unspecified SA peers for transport
  298          * mode; for tunnel mode they must already be filled in.
  299          */
  300         *saidx = isr->saidx;
  301         if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
  302                 /* Fillin unspecified SA peers only for transport mode */
  303                 if (af == AF_INET) {
  304                         struct sockaddr_in *sin;
  305                         struct ip *ip = mtod(m, struct ip *);
  306 
  307                         if (saidx->src.sa.sa_len == 0) {
  308                                 sin = &saidx->src.sin;
  309                                 sin->sin_len = sizeof(*sin);
  310                                 sin->sin_family = AF_INET;
  311                                 sin->sin_port = IPSEC_PORT_ANY;
  312                                 sin->sin_addr = ip->ip_src;
  313                         }
  314                         if (saidx->dst.sa.sa_len == 0) {
  315                                 sin = &saidx->dst.sin;
  316                                 sin->sin_len = sizeof(*sin);
  317                                 sin->sin_family = AF_INET;
  318                                 sin->sin_port = IPSEC_PORT_ANY;
  319                                 sin->sin_addr = ip->ip_dst;
  320                         }
  321                 } else {
  322                         struct sockaddr_in6 *sin6;
  323                         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  324 
  325                         if (saidx->src.sin6.sin6_len == 0) {
  326                                 sin6 = (struct sockaddr_in6 *)&saidx->src;
  327                                 sin6->sin6_len = sizeof(*sin6);
  328                                 sin6->sin6_family = AF_INET6;
  329                                 sin6->sin6_port = IPSEC_PORT_ANY;
  330                                 sin6->sin6_addr = ip6->ip6_src;
  331                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
  332                                         /* fix scope id for comparing SPD */
  333                                         sin6->sin6_addr.s6_addr16[1] = 0;
  334                                         sin6->sin6_scope_id =
  335                                             ntohs(ip6->ip6_src.s6_addr16[1]);
  336                                 }
  337                         }
  338                         if (saidx->dst.sin6.sin6_len == 0) {
  339                                 sin6 = (struct sockaddr_in6 *)&saidx->dst;
  340                                 sin6->sin6_len = sizeof(*sin6);
  341                                 sin6->sin6_family = AF_INET6;
  342                                 sin6->sin6_port = IPSEC_PORT_ANY;
  343                                 sin6->sin6_addr = ip6->ip6_dst;
  344                                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
  345                                         /* fix scope id for comparing SPD */
  346                                         sin6->sin6_addr.s6_addr16[1] = 0;
  347                                         sin6->sin6_scope_id =
  348                                             ntohs(ip6->ip6_dst.s6_addr16[1]);
  349                                 }
  350                         }
  351                 }
  352         }
  353 
  354         /*
  355          * Lookup SA and validate it.
  356          */
  357         *error = key_checkrequest(isr, saidx);
  358         if (*error != 0) {
  359                 /*
  360                  * IPsec processing is required, but no SA found.
  361                  * I assume that key_acquire() had been called
  362                  * to get/establish the SA. Here I discard
  363                  * this packet because it is responsibility for
  364                  * upper layer to retransmit the packet.
  365                  */
  366                 V_ipsec4stat.ips_out_nosa++;
  367                 goto bad;
  368         }
  369         sav = isr->sav;
  370         if (sav == NULL) {
  371                 IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
  372                         ("no SA found, but required; level %u",
  373                         ipsec_get_reqlevel(isr)));
  374                 IPSECREQUEST_UNLOCK(isr);
  375                 isr = isr->next;
  376                 /*
  377                  * If isr is NULL, we found a 'use' policy w/o SA.
  378                  * Return w/o error and w/o isr so we can drop out
  379                  * and continue w/o IPsec processing.
  380                  */
  381                 if (isr == NULL)
  382                         return isr;
  383                 IPSECREQUEST_LOCK(isr);
  384                 goto again;
  385         }
  386 
  387         /*
  388          * Check system global policy controls.
  389          */
  390         if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
  391             (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
  392             (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
  393                 DPRINTF(("%s: IPsec outbound packet dropped due"
  394                         " to policy (check your sysctls)\n", __func__));
  395                 IPSEC_OSTAT(V_espstat.esps_pdrops, V_ahstat.ahs_pdrops,
  396                     V_ipcompstat.ipcomps_pdrops);
  397                 *error = EHOSTUNREACH;
  398                 goto bad;
  399         }
  400 
  401         /*
  402          * Sanity check the SA contents for the caller
  403          * before they invoke the xform output method.
  404          */
  405         if (sav->tdb_xform == NULL) {
  406                 DPRINTF(("%s: no transform for SA\n", __func__));
  407                 IPSEC_OSTAT(V_espstat.esps_noxform, V_ahstat.ahs_noxform,
  408                     V_ipcompstat.ipcomps_noxform);
  409                 *error = EHOSTUNREACH;
  410                 goto bad;
  411         }
  412         return isr;
  413 bad:
  414         IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
  415         IPSECREQUEST_UNLOCK(isr);
  416         return NULL;
  417 #undef IPSEC_OSTAT
  418 }
  419 
  420 #ifdef INET
  421 /*
  422  * IPsec output logic for IPv4.
  423  */
  424 int
  425 ipsec4_process_packet(
  426         struct mbuf *m,
  427         struct ipsecrequest *isr,
  428         int flags,
  429         int tunalready)
  430 {
  431         struct secasindex saidx;
  432         struct secasvar *sav;
  433         struct ip *ip;
  434         int error, i, off;
  435 
  436         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  437         IPSEC_ASSERT(isr != NULL, ("null isr"));
  438 
  439         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  440 
  441         isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
  442         if (isr == NULL) {
  443                 if (error != 0)
  444                         goto bad;
  445                 return EJUSTRETURN;
  446         }
  447 
  448         sav = isr->sav;
  449 
  450 #ifdef DEV_ENC
  451         encif->if_opackets++;
  452         encif->if_obytes += m->m_pkthdr.len;
  453 
  454         /* pass the mbuf to enc0 for bpf processing */
  455         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_BEFORE);
  456         /* pass the mbuf to enc0 for packet filtering */
  457         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  458                 goto bad;
  459 #endif
  460 
  461         if (!tunalready) {
  462                 union sockaddr_union *dst = &sav->sah->saidx.dst;
  463                 int setdf;
  464 
  465                 /*
  466                  * Collect IP_DF state from the outer header.
  467                  */
  468                 if (dst->sa.sa_family == AF_INET) {
  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                         /* Honor system-wide control of how to handle IP_DF */
  476                         switch (V_ip4_ipsec_dfbit) {
  477                         case 0:                 /* clear in outer header */
  478                         case 1:                 /* set in outer header */
  479                                 setdf = V_ip4_ipsec_dfbit;
  480                                 break;
  481                         default:                /* propagate to outer header */
  482                                 setdf = ntohs(ip->ip_off & IP_DF);
  483                                 break;
  484                         }
  485                 } else {
  486                         ip = NULL;              /* keep compiler happy */
  487                         setdf = 0;
  488                 }
  489                 /* Do the appropriate encapsulation, if necessary */
  490                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
  491                     dst->sa.sa_family != AF_INET ||         /* PF mismatch */
  492 #if 0
  493                     (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
  494                     sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
  495 #endif
  496                     (dst->sa.sa_family == AF_INET &&        /* Proxy */
  497                      dst->sin.sin_addr.s_addr != INADDR_ANY &&
  498                      dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
  499                         struct mbuf *mp;
  500 
  501                         /* Fix IPv4 header checksum and length */
  502                         if (m->m_len < sizeof (struct ip) &&
  503                             (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  504                                 error = ENOBUFS;
  505                                 goto bad;
  506                         }
  507                         ip = mtod(m, struct ip *);
  508                         ip->ip_len = htons(m->m_pkthdr.len);
  509                         ip->ip_sum = 0;
  510 #ifdef _IP_VHL
  511                         if (ip->ip_vhl == IP_VHL_BORING)
  512                                 ip->ip_sum = in_cksum_hdr(ip);
  513                         else
  514                                 ip->ip_sum = in_cksum(m,
  515                                         _IP_VHL_HL(ip->ip_vhl) << 2);
  516 #else
  517                         ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  518 #endif
  519 
  520                         /* Encapsulate the packet */
  521                         error = ipip_output(m, isr, &mp, 0, 0);
  522                         if (mp == NULL && !error) {
  523                                 /* Should never happen. */
  524                                 DPRINTF(("%s: ipip_output returns no mbuf and "
  525                                         "no error!", __func__));
  526                                 error = EFAULT;
  527                         }
  528                         if (error) {
  529                                 if (mp) {
  530                                         /* XXX: Should never happen! */
  531                                         m_freem(mp);
  532                                 }
  533                                 m = NULL; /* ipip_output() already freed it */
  534                                 goto bad;
  535                         }
  536                         m = mp, mp = NULL;
  537                         /*
  538                          * ipip_output clears IP_DF in the new header.  If
  539                          * we need to propagate IP_DF from the outer header,
  540                          * then we have to do it here.
  541                          *
  542                          * XXX shouldn't assume what ipip_output does.
  543                          */
  544                         if (dst->sa.sa_family == AF_INET && setdf) {
  545                                 if (m->m_len < sizeof (struct ip) &&
  546                                     (m = m_pullup(m, sizeof (struct ip))) == NULL) {
  547                                         error = ENOBUFS;
  548                                         goto bad;
  549                                 }
  550                                 ip = mtod(m, struct ip *);
  551                                 ip->ip_off = ntohs(ip->ip_off);
  552                                 ip->ip_off |= IP_DF;
  553                                 ip->ip_off = htons(ip->ip_off);
  554                         }
  555                 }
  556         }
  557 
  558 #ifdef DEV_ENC
  559         /* pass the mbuf to enc0 for bpf processing */
  560         ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_AFTER);
  561         /* pass the mbuf to enc0 for packet filtering */
  562         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  563                 goto bad;
  564 #endif
  565 
  566         /*
  567          * Dispatch to the appropriate IPsec transform logic.  The
  568          * packet will be returned for transmission after crypto
  569          * processing, etc. are completed.  For encapsulation we
  570          * bypass this call because of the explicit call done above
  571          * (necessary to deal with IP_DF handling for IPv4).
  572          *
  573          * NB: m & sav are ``passed to caller'' who's reponsible for
  574          *     for reclaiming their resources.
  575          */
  576         if (sav->tdb_xform->xf_type != XF_IP4) {
  577                 ip = mtod(m, struct ip *);
  578                 i = ip->ip_hl << 2;
  579                 off = offsetof(struct ip, ip_p);
  580                 error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
  581         } else {
  582                 error = ipsec_process_done(m, isr);
  583         }
  584         IPSECREQUEST_UNLOCK(isr);
  585         return error;
  586 bad:
  587         if (isr)
  588                 IPSECREQUEST_UNLOCK(isr);
  589         if (m)
  590                 m_freem(m);
  591         return error;
  592 }
  593 #endif
  594 
  595 #ifdef INET6
  596 /*
  597  * Chop IP6 header from the payload.
  598  */
  599 static struct mbuf *
  600 ipsec6_splithdr(struct mbuf *m)
  601 {
  602         struct mbuf *mh;
  603         struct ip6_hdr *ip6;
  604         int hlen;
  605 
  606         IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
  607                 ("first mbuf too short, len %u", m->m_len));
  608         ip6 = mtod(m, struct ip6_hdr *);
  609         hlen = sizeof(struct ip6_hdr);
  610         if (m->m_len > hlen) {
  611                 MGETHDR(mh, M_DONTWAIT, MT_DATA);
  612                 if (!mh) {
  613                         m_freem(m);
  614                         return NULL;
  615                 }
  616                 M_MOVE_PKTHDR(mh, m);
  617                 MH_ALIGN(mh, hlen);
  618                 m->m_len -= hlen;
  619                 m->m_data += hlen;
  620                 mh->m_next = m;
  621                 m = mh;
  622                 m->m_len = hlen;
  623                 bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
  624         } else if (m->m_len < hlen) {
  625                 m = m_pullup(m, hlen);
  626                 if (!m)
  627                         return NULL;
  628         }
  629         return m;
  630 }
  631 
  632 /*
  633  * IPsec output logic for IPv6, transport mode.
  634  */
  635 int
  636 ipsec6_output_trans(
  637         struct ipsec_output_state *state,
  638         u_char *nexthdrp,
  639         struct mbuf *mprev,
  640         struct secpolicy *sp,
  641         int flags,
  642         int *tun)
  643 {
  644         struct ipsecrequest *isr;
  645         struct secasindex saidx;
  646         int error = 0;
  647         struct mbuf *m;
  648 
  649         IPSEC_ASSERT(state != NULL, ("null state"));
  650         IPSEC_ASSERT(state->m != NULL, ("null m"));
  651         IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
  652         IPSEC_ASSERT(mprev != NULL, ("null mprev"));
  653         IPSEC_ASSERT(sp != NULL, ("null sp"));
  654         IPSEC_ASSERT(tun != NULL, ("null tun"));
  655 
  656         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  657                 printf("%s: applied SP\n", __func__);
  658                 kdebug_secpolicy(sp));
  659 
  660         isr = sp->req;
  661         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  662                 /* the rest will be handled by ipsec6_output_tunnel() */
  663                 *tun = 1;               /* need tunnel-mode processing */
  664                 return 0;
  665         }
  666 
  667         *tun = 0;
  668         m = state->m;
  669 
  670         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  671         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  672         if (isr == NULL) {
  673                 if (error != 0) {
  674 #ifdef notdef
  675                         /* XXX should notification be done for all errors ? */
  676                         /*
  677                          * Notify the fact that the packet is discarded
  678                          * to ourselves. I believe this is better than
  679                          * just silently discarding. (jinmei@kame.net)
  680                          * XXX: should we restrict the error to TCP packets?
  681                          * XXX: should we directly notify sockets via
  682                          *      pfctlinputs?
  683                          */
  684                         icmp6_error(m, ICMP6_DST_UNREACH,
  685                                     ICMP6_DST_UNREACH_ADMIN, 0);
  686                         m = NULL;       /* NB: icmp6_error frees mbuf */
  687 #endif
  688                         goto bad;
  689                 }
  690                 return EJUSTRETURN;
  691         }
  692 
  693         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  694                                                   sizeof (struct ip6_hdr),
  695                                                   offsetof(struct ip6_hdr, 
  696                                                            ip6_nxt));
  697         IPSECREQUEST_UNLOCK(isr);
  698         return error;
  699 bad:
  700         if (isr)
  701                 IPSECREQUEST_UNLOCK(isr);
  702         if (m)
  703                 m_freem(m);
  704         state->m = NULL;
  705         return error;
  706 }
  707 
  708 static int
  709 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
  710 {
  711         struct ip6_hdr *oip6;
  712         struct ip6_hdr *ip6;
  713         size_t plen;
  714 
  715         /* can't tunnel between different AFs */
  716         if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
  717             sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
  718                 m_freem(m);
  719                 return EINVAL;
  720         }
  721         IPSEC_ASSERT(m->m_len == sizeof (struct ip6_hdr),
  722                 ("mbuf wrong size; len %u", m->m_len));
  723 
  724 
  725         /*
  726          * grow the mbuf to accomodate the new IPv6 header.
  727          */
  728         plen = m->m_pkthdr.len;
  729         if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
  730                 struct mbuf *n;
  731                 MGET(n, M_DONTWAIT, MT_DATA);
  732                 if (!n) {
  733                         m_freem(m);
  734                         return ENOBUFS;
  735                 }
  736                 n->m_len = sizeof(struct ip6_hdr);
  737                 n->m_next = m->m_next;
  738                 m->m_next = n;
  739                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  740                 oip6 = mtod(n, struct ip6_hdr *);
  741         } else {
  742                 m->m_next->m_len += sizeof(struct ip6_hdr);
  743                 m->m_next->m_data -= sizeof(struct ip6_hdr);
  744                 m->m_pkthdr.len += sizeof(struct ip6_hdr);
  745                 oip6 = mtod(m->m_next, struct ip6_hdr *);
  746         }
  747         ip6 = mtod(m, struct ip6_hdr *);
  748         bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
  749 
  750         /* Fake link-local scope-class addresses */
  751         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
  752                 oip6->ip6_src.s6_addr16[1] = 0;
  753         if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
  754                 oip6->ip6_dst.s6_addr16[1] = 0;
  755 
  756         /* construct new IPv6 header. see RFC 2401 5.1.2.2 */
  757         /* ECN consideration. */
  758         ip6_ecn_ingress(V_ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
  759         if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
  760                 ip6->ip6_plen = htons(plen);
  761         else {
  762                 /* ip6->ip6_plen will be updated in ip6_output() */
  763         }
  764         ip6->ip6_nxt = IPPROTO_IPV6;
  765         ip6->ip6_src = sav->sah->saidx.src.sin6.sin6_addr;
  766         ip6->ip6_dst = sav->sah->saidx.dst.sin6.sin6_addr;
  767         ip6->ip6_hlim = IPV6_DEFHLIM;
  768 
  769         /* XXX Should ip6_src be updated later ? */
  770 
  771         return 0;
  772 }
  773 
  774 /*
  775  * IPsec output logic for IPv6, tunnel mode.
  776  */
  777 int
  778 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
  779 {
  780         struct ip6_hdr *ip6;
  781         struct ipsecrequest *isr;
  782         struct secasindex saidx;
  783         int error;
  784         struct sockaddr_in6 *dst6;
  785         struct mbuf *m;
  786 
  787         IPSEC_ASSERT(state != NULL, ("null state"));
  788         IPSEC_ASSERT(state->m != NULL, ("null m"));
  789         IPSEC_ASSERT(sp != NULL, ("null sp"));
  790 
  791         KEYDEBUG(KEYDEBUG_IPSEC_DATA,
  792                 printf("%s: applied SP\n", __func__);
  793                 kdebug_secpolicy(sp));
  794 
  795         m = state->m;
  796         /*
  797          * transport mode ipsec (before the 1st tunnel mode) is already
  798          * processed by ipsec6_output_trans().
  799          */
  800         for (isr = sp->req; isr; isr = isr->next) {
  801                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  802                         break;
  803         }
  804 
  805         IPSECREQUEST_LOCK(isr);         /* insure SA contents don't change */
  806         isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
  807         if (isr == NULL) {
  808                 if (error != 0)
  809                         goto bad;
  810                 return EJUSTRETURN; 
  811         }
  812 
  813 #ifdef DEV_ENC
  814         encif->if_opackets++;
  815         encif->if_obytes += m->m_pkthdr.len;
  816 
  817         /* pass the mbuf to enc0 for bpf processing */
  818         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_BEFORE);
  819         /* pass the mbuf to enc0 for packet filtering */
  820         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
  821                 goto bad;
  822 #endif
  823 
  824         /*
  825          * There may be the case that SA status will be changed when
  826          * we are refering to one. So calling splsoftnet().
  827          */
  828         if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
  829                 /*
  830                  * build IPsec tunnel.
  831                  */
  832                 /* XXX should be processed with other familiy */
  833                 if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
  834                         ipseclog((LOG_ERR, "%s: family mismatched between "
  835                             "inner and outer, spi=%u\n", __func__,
  836                             ntohl(isr->sav->spi)));
  837                         V_ipsec6stat.ips_out_inval++;
  838                         error = EAFNOSUPPORT;
  839                         goto bad;
  840                 }
  841 
  842                 m = ipsec6_splithdr(m);
  843                 if (!m) {
  844                         V_ipsec6stat.ips_out_nomem++;
  845                         error = ENOMEM;
  846                         goto bad;
  847                 }
  848                 error = ipsec6_encapsulate(m, isr->sav);
  849                 if (error) {
  850                         m = NULL;
  851                         goto bad;
  852                 }
  853                 ip6 = mtod(m, struct ip6_hdr *);
  854 
  855                 state->ro =
  856                     (struct route *)&isr->sav->sah->route_cache.sin6_route;
  857                 state->dst = (struct sockaddr *)&state->ro->ro_dst;
  858                 dst6 = (struct sockaddr_in6 *)state->dst;
  859                 if (state->ro->ro_rt
  860                  && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
  861                   || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
  862                         RTFREE(state->ro->ro_rt);
  863                         state->ro->ro_rt = NULL;
  864                 }
  865                 if (state->ro->ro_rt == NULL) {
  866                         bzero(dst6, sizeof(*dst6));
  867                         dst6->sin6_family = AF_INET6;
  868                         dst6->sin6_len = sizeof(*dst6);
  869                         dst6->sin6_addr = ip6->ip6_dst;
  870                         rtalloc(state->ro);
  871                 }
  872                 if (state->ro->ro_rt == NULL) {
  873                         V_ip6stat.ip6s_noroute++;
  874                         V_ipsec6stat.ips_out_noroute++;
  875                         error = EHOSTUNREACH;
  876                         goto bad;
  877                 }
  878 
  879                 /* adjust state->dst if tunnel endpoint is offlink */
  880                 if (state->ro->ro_rt->rt_flags & RTF_GATEWAY)
  881                         state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
  882         }
  883 
  884         m = ipsec6_splithdr(m);
  885         if (!m) {
  886                 V_ipsec6stat.ips_out_nomem++;
  887                 error = ENOMEM;
  888                 goto bad;
  889         }
  890         ip6 = mtod(m, struct ip6_hdr *);
  891 
  892 #ifdef DEV_ENC
  893         /* pass the mbuf to enc0 for bpf processing */
  894         ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_AFTER);
  895         /* pass the mbuf to enc0 for packet filtering */
  896         if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
  897                 goto bad;
  898 #endif
  899 
  900         error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
  901                 sizeof (struct ip6_hdr),
  902                 offsetof(struct ip6_hdr, ip6_nxt));
  903         IPSECREQUEST_UNLOCK(isr);
  904         return error;
  905 bad:
  906         if (isr)
  907                 IPSECREQUEST_UNLOCK(isr);
  908         if (m)
  909                 m_freem(m);
  910         state->m = NULL;
  911         return error;
  912 }
  913 #endif /*INET6*/

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