bsd/netinet6/esp_output.c

   1 /*      $FreeBSD: src/sys/netinet6/esp_output.c,v 1.1.2.3 2002/04/28 05:40:26 suz Exp $ */
   2 /*      $KAME: esp_output.c,v 1.44 2001/07/26 06:53:15 jinmei Exp $     */
   3
   4 /*
   5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #define _IP_VHL
  34
  35 /*
  36  * RFC1827/2406 Encapsulated Security Payload.
  37  */
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/malloc.h>
  42 #include <sys/mbuf.h>
  43 #include <sys/domain.h>
  44 #include <sys/protosw.h>
  45 #include <sys/socket.h>
  46 #include <sys/socketvar.h>
  47 #include <sys/errno.h>
  48 #include <sys/time.h>
  49 #include <sys/kernel.h>
  50 #include <sys/syslog.h>
  51
  52 #include <net/if.h>
  53 #include <net/route.h>
  54
  55 #include <netinet/in.h>
  56 #include <netinet/in_systm.h>
  57 #include <netinet/ip.h>
  58 #include <netinet/in_var.h>
  59 #include <netinet/udp.h> /* for nat traversal */
  60
  61 #if INET6
  62 #include <netinet/ip6.h>
  63 #include <netinet6/ip6_var.h>
  64 #include <netinet/icmp6.h>
  65 #endif
  66
  67 #include <netinet6/ipsec.h>
  68 #if INET6
  69 #include <netinet6/ipsec6.h>
  70 #endif
  71 #include <netinet6/ah.h>
  72 #if INET6
  73 #include <netinet6/ah6.h>
  74 #endif
  75 #include <netinet6/esp.h>
  76 #if INET6
  77 #include <netinet6/esp6.h>
  78 #endif
  79 #include <netkey/key.h>
  80 #include <netkey/keydb.h>
  81
  82 #include <net/net_osdep.h>
  83
  84 #include <sys/kdebug.h>
  85 #define DBG_LAYER_BEG           NETDBG_CODE(DBG_NETIPSEC, 1)
  86 #define DBG_LAYER_END           NETDBG_CODE(DBG_NETIPSEC, 3)
  87 #define DBG_FNC_ESPOUT          NETDBG_CODE(DBG_NETIPSEC, (4 << 8))
  88 #define DBG_FNC_ENCRYPT         NETDBG_CODE(DBG_NETIPSEC, (5 << 8))
  89
  90 static int esp_output(struct mbuf *, u_char *, struct mbuf *,
  91         struct ipsecrequest *, int);
  92
  93 extern int      esp_udp_encap_port;
  94 extern u_int32_t natt_now;
  95
  96 /*
  97  * compute ESP header size.
  98  */
  99 size_t
 100 esp_hdrsiz(isr)
 101         struct ipsecrequest *isr;
 102 {
 103         struct secasvar *sav;
 104         const struct esp_algorithm *algo;
 105         const struct ah_algorithm *aalgo;
 106         size_t ivlen;
 107         size_t authlen;
 108         size_t hdrsiz;
 109         size_t maxpad;
 110
 111         /* sanity check */
 112         if (isr == NULL)
 113                 panic("esp_hdrsiz: NULL was passed.\n");
 114
 115         sav = isr->sav;
 116
 117         if (isr->saidx.proto != IPPROTO_ESP)
 118                 panic("unsupported mode passed to esp_hdrsiz");
 119
 120         if (sav == NULL)
 121                 goto estimate;
 122         if (sav->state != SADB_SASTATE_MATURE
 123          && sav->state != SADB_SASTATE_DYING)
 124                 goto estimate;
 125
 126         /* we need transport mode ESP. */
 127         algo = esp_algorithm_lookup(sav->alg_enc);
 128         if (!algo)
 129                 goto estimate;
 130         ivlen = sav->ivlen;
 131         if (ivlen < 0)
 132                 goto estimate;
 133
 134         if (algo->padbound)
 135                 maxpad = algo->padbound;
 136         else
 137                 maxpad = 4;
 138         maxpad += 1; /* maximum 'extendsiz' is padbound + 1, see esp_output */
 139
 140         if (sav->flags & SADB_X_EXT_OLD) {
 141                 /* RFC 1827 */
 142                 hdrsiz = sizeof(struct esp) + ivlen + maxpad;
 143         } else {
 144                 /* RFC 2406 */
 145                 aalgo = ah_algorithm_lookup(sav->alg_auth);
 146                 if (aalgo && sav->replay && sav->key_auth)
 147                         authlen = (aalgo->sumsiz)(sav);
 148                 else
 149                         authlen = 0;
 150                 hdrsiz = sizeof(struct newesp) + ivlen + maxpad + authlen;
 151         }
 152
 153         /*
 154          * If the security association indicates that NATT is required,
 155          * add the size of the NATT encapsulation header:
 156          */
 157         if ((sav->flags & SADB_X_EXT_NATT) != 0) hdrsiz += sizeof(struct udphdr) + 4;
 158
 159         return hdrsiz;
 160
 161    estimate:
 162         /*
 163          * ASSUMING:
 164          *      sizeof(struct newesp) > sizeof(struct esp). (8)
 165          *      esp_max_ivlen() = max ivlen for CBC mode
 166          *      17 = (maximum padding length without random padding length)
 167          *         + (Pad Length field) + (Next Header field).
 168          *      16 = maximum ICV we support.
 169          *  sizeof(struct udphdr) in case NAT traversal is used
 170          */
 171         return sizeof(struct newesp) + esp_max_ivlen() + 17 + 16 + sizeof(struct udphdr);
 172 }
 173
 174 /*
 175  * Modify the packet so that the payload is encrypted.
 176  * The mbuf (m) must start with IPv4 or IPv6 header.
 177  * On failure, free the given mbuf and return NULL.
 178  *
 179  * on invocation:
 180  *      m   nexthdrp md
 181  *      v   v        v
 182  *      IP ......... payload
 183  * during the encryption:
 184  *      m   nexthdrp mprev md
 185  *      v   v        v     v
 186  *      IP ............... esp iv payload pad padlen nxthdr
 187  *                         <--><-><------><--------------->
 188  *                         esplen plen    extendsiz
 189  *                             ivlen
 190  *                         <-----> esphlen
 191  *      <-> hlen
 192  *      <-----------------> espoff
 193  */
 194 static int
 195 esp_output(m, nexthdrp, md, isr, af)
 196         struct mbuf *m;
 197         u_char *nexthdrp;
 198         struct mbuf *md;
 199         struct ipsecrequest *isr;
 200         int af;
 201 {
 202         struct mbuf *n;
 203         struct mbuf *mprev;
 204         struct esp *esp;
 205         struct esptail *esptail;
 206         struct secasvar *sav = isr->sav;
 207         const struct esp_algorithm *algo;
 208         u_int32_t spi;
 209         u_int8_t nxt = 0;
 210         size_t plen;    /*payload length to be encrypted*/
 211         size_t espoff;
 212         int ivlen;
 213         int afnumber;
 214         size_t extendsiz;
 215         int error = 0;
 216         struct ipsecstat *stat;
 217         struct udphdr *udp = NULL;
 218         int     udp_encapsulate = (sav->flags & SADB_X_EXT_NATT && af == AF_INET &&
 219                         (esp_udp_encap_port & 0xFFFF) != 0);
 220
 221         KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_START, sav->ivlen,0,0,0,0);
 222         switch (af) {
 223 #if INET
 224         case AF_INET:
 225                 afnumber = 4;
 226                 stat = &ipsecstat;
 227                 break;
 228 #endif
 229 #if INET6
 230         case AF_INET6:
 231                 afnumber = 6;
 232                 stat = &ipsec6stat;
 233                 break;
 234 #endif
 235         default:
 236                 ipseclog((LOG_ERR, "esp_output: unsupported af %d\n", af));
 237                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 1,0,0,0,0);
 238                 return 0;       /* no change at all */
 239         }
 240
 241         /* some sanity check */
 242         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 243                 switch (af) {
 244 #if INET
 245                 case AF_INET:
 246                     {
 247                         struct ip *ip;
 248
 249                         ip = mtod(m, struct ip *);
 250                         ipseclog((LOG_DEBUG, "esp4_output: internal error: "
 251                                 "sav->replay is null: %x->%x, SPI=%u\n",
 252                                 (u_int32_t)ntohl(ip->ip_src.s_addr),
 253                                 (u_int32_t)ntohl(ip->ip_dst.s_addr),
 254                                 (u_int32_t)ntohl(sav->spi)));
 255                         ipsecstat.out_inval++;
 256                         break;
 257                     }
 258 #endif /*INET*/
 259 #if INET6
 260                 case AF_INET6:
 261                         ipseclog((LOG_DEBUG, "esp6_output: internal error: "
 262                                 "sav->replay is null: SPI=%u\n",
 263                                 (u_int32_t)ntohl(sav->spi)));
 264                         ipsec6stat.out_inval++;
 265                         break;
 266 #endif /*INET6*/
 267                 default:
 268                         panic("esp_output: should not reach here");
 269                 }
 270                 m_freem(m);
 271                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 2,0,0,0,0);
 272                 return EINVAL;
 273         }
 274
 275         algo = esp_algorithm_lookup(sav->alg_enc);
 276         if (!algo) {
 277                 ipseclog((LOG_ERR, "esp_output: unsupported algorithm: "
 278                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 279                 m_freem(m);
 280                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 3,0,0,0,0);
 281                 return EINVAL;
 282         }
 283         spi = sav->spi;
 284         ivlen = sav->ivlen;
 285         /* should be okey */
 286         if (ivlen < 0) {
 287                 panic("invalid ivlen");
 288         }
 289
 290     {
 291         /*
 292          * insert ESP header.
 293          * XXX inserts ESP header right after IPv4 header.  should
 294          * chase the header chain.
 295          * XXX sequential number
 296          */
 297 #if INET
 298         struct ip *ip = NULL;
 299 #endif
 300 #if INET6
 301         struct ip6_hdr *ip6 = NULL;
 302 #endif
 303         size_t esplen;  /* sizeof(struct esp/newesp) */
 304         size_t esphlen; /* sizeof(struct esp/newesp) + ivlen */
 305         size_t hlen = 0;        /* ip header len */
 306
 307         if (sav->flags & SADB_X_EXT_OLD) {
 308                 /* RFC 1827 */
 309                 esplen = sizeof(struct esp);
 310         } else {
 311                 /* RFC 2406 */
 312                 if (sav->flags & SADB_X_EXT_DERIV)
 313                         esplen = sizeof(struct esp);
 314                 else
 315                         esplen = sizeof(struct newesp);
 316         }
 317         esphlen = esplen + ivlen;
 318
 319         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 320                 ;
 321         if (mprev == NULL || mprev->m_next != md) {
 322                 ipseclog((LOG_DEBUG, "esp%d_output: md is not in chain\n",
 323                     afnumber));
 324                 m_freem(m);
 325                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 4,0,0,0,0);
 326                 return EINVAL;
 327         }
 328
 329         plen = 0;
 330         for (n = md; n; n = n->m_next)
 331                 plen += n->m_len;
 332
 333         switch (af) {
 334 #if INET
 335         case AF_INET:
 336                 ip = mtod(m, struct ip *);
 337 #ifdef _IP_VHL
 338                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 339 #else
 340                 hlen = ip->ip_hl << 2;
 341 #endif
 342                 break;
 343 #endif
 344 #if INET6
 345         case AF_INET6:
 346                 ip6 = mtod(m, struct ip6_hdr *);
 347                 hlen = sizeof(*ip6);
 348                 break;
 349 #endif
 350         }
 351
 352         /* make the packet over-writable */
 353         mprev->m_next = NULL;
 354         if ((md = ipsec_copypkt(md)) == NULL) {
 355                 m_freem(m);
 356                 error = ENOBUFS;
 357                 goto fail;
 358         }
 359         mprev->m_next = md;
 360
 361         espoff = m->m_pkthdr.len - plen;
 362
 363         if (udp_encapsulate) {
 364                 esphlen += sizeof(struct udphdr);
 365                 espoff += sizeof(struct udphdr);
 366         }
 367
 368         /*
 369          * grow the mbuf to accomodate ESP header.
 370          * before: IP ... payload
 371          * after:  IP ... [UDP] ESP IV payload
 372          */
 373         if (M_LEADINGSPACE(md) < esphlen || (md->m_flags & M_EXT) != 0) {
 374                 MGET(n, M_DONTWAIT, MT_DATA);
 375                 if (!n) {
 376                         m_freem(m);
 377                         error = ENOBUFS;
 378                         goto fail;
 379                 }
 380                 n->m_len = esphlen;
 381                 mprev->m_next = n;
 382                 n->m_next = md;
 383                 m->m_pkthdr.len += esphlen;
 384                 if (udp_encapsulate) {
 385                         udp = mtod(n, struct udphdr *);
 386                         esp = (struct esp *)((caddr_t)udp + sizeof(struct udphdr));
 387                 } else {
 388                         esp = mtod(n, struct esp *);
 389                 }
 390         } else {
 391                 md->m_len += esphlen;
 392                 md->m_data -= esphlen;
 393                 m->m_pkthdr.len += esphlen;
 394                 esp = mtod(md, struct esp *);
 395                 if (udp_encapsulate) {
 396                         udp = mtod(md, struct udphdr *);
 397                         esp = (struct esp *)((caddr_t)udp + sizeof(struct udphdr));
 398                 } else {
 399                         esp = mtod(md, struct esp *);
 400                 }
 401         }
 402
 403         switch (af) {
 404 #if INET
 405         case AF_INET:
 406                 if (esphlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
 407                         ip->ip_len = htons(ntohs(ip->ip_len) + esphlen);
 408                 else {
 409                         ipseclog((LOG_ERR,
 410                             "IPv4 ESP output: size exceeds limit\n"));
 411                         ipsecstat.out_inval++;
 412                         m_freem(m);
 413                         error = EMSGSIZE;
 414                         goto fail;
 415                 }
 416                 break;
 417 #endif
 418 #if INET6
 419         case AF_INET6:
 420                 /* total packet length will be computed in ip6_output() */
 421                 break;
 422 #endif
 423         }
 424     }
 425
 426         /* initialize esp header. */
 427         esp->esp_spi = spi;
 428         if ((sav->flags & SADB_X_EXT_OLD) == 0) {
 429                 struct newesp *nesp;
 430                 nesp = (struct newesp *)esp;
 431                 if (sav->replay->count == ~0) {
 432                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 433                                 /* XXX Is it noisy ? */
 434                                 ipseclog((LOG_WARNING,
 435                                     "replay counter overflowed. %s\n",
 436                                     ipsec_logsastr(sav)));
 437                                 stat->out_inval++;
 438                                 m_freem(m);
 439                                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 5,0,0,0,0);
 440                                 return EINVAL;
 441                         }
 442                 }
 443                 sav->replay->count++;
 444                 /*
 445                  * XXX sequence number must not be cycled, if the SA is
 446                  * installed by IKE daemon.
 447                  */
 448                 nesp->esp_seq = htonl(sav->replay->count);
 449         }
 450
 451     {
 452         /*
 453          * find the last mbuf. make some room for ESP trailer.
 454          */
 455 #if INET
 456         struct ip *ip = NULL;
 457 #endif
 458         size_t padbound;
 459         u_char *extend;
 460         int i;
 461         int randpadmax;
 462
 463         if (algo->padbound)
 464                 padbound = algo->padbound;
 465         else
 466                 padbound = 4;
 467         /* ESP packet, including nxthdr field, must be length of 4n */
 468         if (padbound < 4)
 469                 padbound = 4;
 470
 471         extendsiz = padbound - (plen % padbound);
 472         if (extendsiz == 1)
 473                 extendsiz = padbound + 1;
 474
 475         /* random padding */
 476         switch (af) {
 477 #if INET
 478         case AF_INET:
 479                 randpadmax = ip4_esp_randpad;
 480                 break;
 481 #endif
 482 #if INET6
 483         case AF_INET6:
 484                 randpadmax = ip6_esp_randpad;
 485                 break;
 486 #endif
 487         default:
 488                 randpadmax = -1;
 489                 break;
 490         }
 491         if (randpadmax < 0 || plen + extendsiz >= randpadmax)
 492                 ;
 493         else {
 494                 int n;
 495
 496                 /* round */
 497                 randpadmax = (randpadmax / padbound) * padbound;
 498                 n = (randpadmax - plen + extendsiz) / padbound;
 499
 500                 if (n > 0)
 501                         n = (random() % n) * padbound;
 502                 else
 503                         n = 0;
 504
 505                 /*
 506                  * make sure we do not pad too much.
 507                  * MLEN limitation comes from the trailer attachment
 508                  * code below.
 509                  * 256 limitation comes from sequential padding.
 510                  * also, the 1-octet length field in ESP trailer imposes
 511                  * limitation (but is less strict than sequential padding
 512                  * as length field do not count the last 2 octets).
 513                  */
 514                 if (extendsiz + n <= MLEN && extendsiz + n < 256)
 515                         extendsiz += n;
 516         }
 517
 518 #if DIAGNOSTIC
 519         if (extendsiz > MLEN || extendsiz >= 256)
 520                 panic("extendsiz too big in esp_output");
 521 #endif
 522
 523         n = m;
 524         while (n->m_next)
 525                 n = n->m_next;
 526
 527         /*
 528          * if M_EXT, the external mbuf data may be shared among
 529          * two consequtive TCP packets, and it may be unsafe to use the
 530          * trailing space.
 531          */
 532         if (!(n->m_flags & M_EXT) && extendsiz < M_TRAILINGSPACE(n)) {
 533                 extend = mtod(n, u_char *) + n->m_len;
 534                 n->m_len += extendsiz;
 535                 m->m_pkthdr.len += extendsiz;
 536         } else {
 537                 struct mbuf *nn;
 538
 539                 MGET(nn, M_DONTWAIT, MT_DATA);
 540                 if (!nn) {
 541                         ipseclog((LOG_DEBUG, "esp%d_output: can't alloc mbuf",
 542                             afnumber));
 543                         m_freem(m);
 544                         error = ENOBUFS;
 545                         goto fail;
 546                 }
 547                 extend = mtod(nn, u_char *);
 548                 nn->m_len = extendsiz;
 549                 nn->m_next = NULL;
 550                 n->m_next = nn;
 551                 n = nn;
 552                 m->m_pkthdr.len += extendsiz;
 553         }
 554         switch (sav->flags & SADB_X_EXT_PMASK) {
 555         case SADB_X_EXT_PRAND:
 556                 key_randomfill(extend, extendsiz);
 557                 break;
 558         case SADB_X_EXT_PZERO:
 559                 bzero(extend, extendsiz);
 560                 break;
 561         case SADB_X_EXT_PSEQ:
 562                 for (i = 0; i < extendsiz; i++)
 563                         extend[i] = (i + 1) & 0xff;
 564                 break;
 565         }
 566
 567         nxt = *nexthdrp;
 568         if (udp_encapsulate) {
 569                 *nexthdrp = IPPROTO_UDP;
 570
 571                 /* Fill out the UDP header */
 572                 udp->uh_sport = ntohs((u_short)esp_udp_encap_port);
 573                 udp->uh_dport = ntohs(sav->remote_ike_port);
 574 //              udp->uh_len set later, after all length tweaks are complete
 575                 udp->uh_sum = 0;
 576
 577                 /* Update last sent so we know if we need to send keepalive */
 578                 sav->natt_last_activity = natt_now;
 579         } else {
 580                 *nexthdrp = IPPROTO_ESP;
 581         }
 582
 583         /* initialize esp trailer. */
 584         esptail = (struct esptail *)
 585                 (mtod(n, u_int8_t *) + n->m_len - sizeof(struct esptail));
 586         esptail->esp_nxt = nxt;
 587         esptail->esp_padlen = extendsiz - 2;
 588
 589         /* modify IP header (for ESP header part only) */
 590         switch (af) {
 591 #if INET
 592         case AF_INET:
 593                 ip = mtod(m, struct ip *);
 594                 if (extendsiz < (IP_MAXPACKET - ntohs(ip->ip_len)))
 595                         ip->ip_len = htons(ntohs(ip->ip_len) + extendsiz);
 596                 else {
 597                         ipseclog((LOG_ERR,
 598                             "IPv4 ESP output: size exceeds limit\n"));
 599                         ipsecstat.out_inval++;
 600                         m_freem(m);
 601                         error = EMSGSIZE;
 602                         goto fail;
 603                 }
 604                 break;
 605 #endif
 606 #if INET6
 607         case AF_INET6:
 608                 /* total packet length will be computed in ip6_output() */
 609                 break;
 610 #endif
 611         }
 612     }
 613
 614         /*
 615          * pre-compute and cache intermediate key
 616          */
 617         error = esp_schedule(algo, sav);
 618         if (error) {
 619                 m_freem(m);
 620                 stat->out_inval++;
 621                 goto fail;
 622         }
 623
 624         /*
 625          * encrypt the packet, based on security association
 626          * and the algorithm specified.
 627          */
 628         if (!algo->encrypt)
 629                 panic("internal error: no encrypt function");
 630         KERNEL_DEBUG(DBG_FNC_ENCRYPT | DBG_FUNC_START, 0,0,0,0,0);
 631         if ((*algo->encrypt)(m, espoff, plen + extendsiz, sav, algo, ivlen)) {
 632                 /* m is already freed */
 633                 ipseclog((LOG_ERR, "packet encryption failure\n"));
 634                 stat->out_inval++;
 635                 error = EINVAL;
 636                 KERNEL_DEBUG(DBG_FNC_ENCRYPT | DBG_FUNC_END, 1,error,0,0,0);
 637                 goto fail;
 638         }
 639         KERNEL_DEBUG(DBG_FNC_ENCRYPT | DBG_FUNC_END, 2,0,0,0,0);
 640
 641         /*
 642          * calculate ICV if required.
 643          */
 644         if (!sav->replay)
 645                 goto noantireplay;
 646         if (!sav->key_auth)
 647                 goto noantireplay;
 648         if (sav->key_auth == SADB_AALG_NONE)
 649                 goto noantireplay;
 650
 651     {
 652         const struct ah_algorithm *aalgo;
 653         u_char authbuf[AH_MAXSUMSIZE];
 654         struct mbuf *n;
 655         u_char *p;
 656         size_t siz;
 657 #if INET
 658         struct ip *ip;
 659 #endif
 660
 661         aalgo = ah_algorithm_lookup(sav->alg_auth);
 662         if (!aalgo)
 663                 goto noantireplay;
 664         siz = ((aalgo->sumsiz)(sav) + 3) & ~(4 - 1);
 665         if (AH_MAXSUMSIZE < siz)
 666                 panic("assertion failed for AH_MAXSUMSIZE");
 667
 668         if (esp_auth(m, espoff, m->m_pkthdr.len - espoff, sav, authbuf)) {
 669                 ipseclog((LOG_ERR, "ESP checksum generation failure\n"));
 670                 m_freem(m);
 671                 error = EINVAL;
 672                 stat->out_inval++;
 673                 goto fail;
 674         }
 675
 676         n = m;
 677         while (n->m_next)
 678                 n = n->m_next;
 679
 680         if (!(n->m_flags & M_EXT) && siz < M_TRAILINGSPACE(n)) { /* XXX */
 681                 n->m_len += siz;
 682                 m->m_pkthdr.len += siz;
 683                 p = mtod(n, u_char *) + n->m_len - siz;
 684         } else {
 685                 struct mbuf *nn;
 686
 687                 MGET(nn, M_DONTWAIT, MT_DATA);
 688                 if (!nn) {
 689                         ipseclog((LOG_DEBUG, "can't alloc mbuf in esp%d_output",
 690                             afnumber));
 691                         m_freem(m);
 692                         error = ENOBUFS;
 693                         goto fail;
 694                 }
 695                 nn->m_len = siz;
 696                 nn->m_next = NULL;
 697                 n->m_next = nn;
 698                 n = nn;
 699                 m->m_pkthdr.len += siz;
 700                 p = mtod(nn, u_char *);
 701         }
 702         bcopy(authbuf, p, siz);
 703
 704         /* modify IP header (for ESP header part only) */
 705         switch (af) {
 706 #if INET
 707         case AF_INET:
 708                 ip = mtod(m, struct ip *);
 709                 if (siz < (IP_MAXPACKET - ntohs(ip->ip_len)))
 710                         ip->ip_len = htons(ntohs(ip->ip_len) + siz);
 711                 else {
 712                         ipseclog((LOG_ERR,
 713                             "IPv4 ESP output: size exceeds limit\n"));
 714                         ipsecstat.out_inval++;
 715                         m_freem(m);
 716                         error = EMSGSIZE;
 717                         goto fail;
 718                 }
 719                 break;
 720 #endif
 721 #if INET6
 722         case AF_INET6:
 723                 /* total packet length will be computed in ip6_output() */
 724                 break;
 725 #endif
 726         }
 727     }
 728
 729         if (udp_encapsulate) {
 730                 struct ip *ip;
 731                 ip = mtod(m, struct ip *);
 732                 udp->uh_ulen = htons(ntohs(ip->ip_len) - (IP_VHL_HL(ip->ip_vhl) << 2));
 733         }
 734
 735
 736 noantireplay:
 737         if (!m) {
 738                 ipseclog((LOG_ERR,
 739                     "NULL mbuf after encryption in esp%d_output", afnumber));
 740         } else
 741                 stat->out_success++;
 742         stat->out_esphist[sav->alg_enc]++;
 743         key_sa_recordxfer(sav, m);
 744         KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 6,0,0,0,0);
 745         return 0;
 746
 747 fail:
 748 #if 1
 749         KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 7,error,0,0,0);
 750         return error;
 751 #else
 752         panic("something bad in esp_output");
 753 #endif
 754 }
 755
 756 #if INET
 757 int
 758 esp4_output(m, isr)
 759         struct mbuf *m;
 760         struct ipsecrequest *isr;
 761 {
 762         struct ip *ip;
 763         if (m->m_len < sizeof(struct ip)) {
 764                 ipseclog((LOG_DEBUG, "esp4_output: first mbuf too short\n"));
 765                 m_freem(m);
 766                 return 0;
 767         }
 768         ip = mtod(m, struct ip *);
 769         /* XXX assumes that m->m_next points to payload */
 770         return esp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
 771 }
 772 #endif /*INET*/
 773
 774 #if INET6
 775 int
 776 esp6_output(m, nexthdrp, md, isr)
 777         struct mbuf *m;
 778         u_char *nexthdrp;
 779         struct mbuf *md;
 780         struct ipsecrequest *isr;
 781 {
 782         if (m->m_len < sizeof(struct ip6_hdr)) {
 783                 ipseclog((LOG_DEBUG, "esp6_output: first mbuf too short\n"));
 784                 m_freem(m);
 785                 return 0;
 786         }
 787         return esp_output(m, nexthdrp, md, isr, AF_INET6);
 788 }
 789 #endif /*INET6*/