bsd/netinet6/ipcomp_output.c

   1 /*      $FreeBSD: src/sys/netinet6/ipcomp_output.c,v 1.1.2.2 2001/07/03 11:01:54 ume Exp $      */
   2 /*      $KAME: ipcomp_output.c,v 1.23 2001/01/23 08:59:37 itojun Exp $  */
   3
   4 /*
   5  * Copyright (C) 1999 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 /*
  34  * RFC2393 IP payload compression protocol (IPComp).
  35  */
  36
  37
  38 #include <sys/param.h>
  39 #include <sys/systm.h>
  40 #include <sys/malloc.h>
  41 #include <sys/mbuf.h>
  42 #include <sys/domain.h>
  43 #include <sys/protosw.h>
  44 #include <sys/socket.h>
  45 #include <sys/errno.h>
  46 #include <sys/time.h>
  47 #include <sys/kernel.h>
  48 #include <sys/syslog.h>
  49
  50 #include <net/if.h>
  51 #include <net/route.h>
  52 #include <libkern/zlib.h>
  53 #include <kern/cpu_number.h>
  54 #include <kern/locks.h>
  55
  56 #include <netinet/in.h>
  57 #include <netinet/in_systm.h>
  58 #include <netinet/in_var.h>
  59 #include <netinet/ip.h>
  60 #include <netinet/ip_var.h>
  61 #include <netinet/ip_ecn.h>
  62
  63 #if INET6
  64 #include <netinet/ip6.h>
  65 #include <netinet6/ip6_var.h>
  66 #endif
  67 #include <netinet6/ipcomp.h>
  68 #if INET6
  69 #include <netinet6/ipcomp6.h>
  70 #endif
  71
  72 #include <netinet6/ipsec.h>
  73 #if INET6
  74 #include <netinet6/ipsec6.h>
  75 #endif
  76 #include <netkey/key.h>
  77 #include <netkey/keydb.h>
  78
  79 #include <net/net_osdep.h>
  80
  81
  82 static int ipcomp_output(struct mbuf *, u_char *, struct mbuf *,
  83         int, struct secasvar *sav);
  84
  85 /*
  86  * Modify the packet so that the payload is compressed.
  87  * The mbuf (m) must start with IPv4 or IPv6 header.
  88  * On failure, free the given mbuf and return non-zero.
  89  *
  90  * on invocation:
  91  *      m   nexthdrp md
  92  *      v   v        v
  93  *      IP ......... payload
  94  * during the encryption:
  95  *      m   nexthdrp mprev md
  96  *      v   v        v     v
  97  *      IP ............... ipcomp payload
  98  *                         <-----><----->
  99  *                         complen  plen
 100  *      <-> hlen
 101  *      <-----------------> compoff
 102  */
 103 static int
 104 ipcomp_output(m, nexthdrp, md, af, sav)
 105         struct mbuf *m;
 106         u_char *nexthdrp;
 107         struct mbuf *md;
 108         int af;
 109         struct secasvar *sav;
 110 {
 111         struct mbuf *n;
 112         struct mbuf *md0;
 113         struct mbuf *mcopy;
 114         struct mbuf *mprev;
 115         struct ipcomp *ipcomp;
 116         const struct ipcomp_algorithm *algo;
 117         u_int16_t cpi;          /* host order */
 118         size_t plen0, plen;     /*payload length to be compressed*/
 119         size_t compoff;
 120         int afnumber;
 121         int error = 0;
 122         struct ipsecstat *stat;
 123
 124         switch (af) {
 125 #if INET
 126         case AF_INET:
 127                 afnumber = 4;
 128                 stat = &ipsecstat;
 129                 break;
 130 #endif
 131 #if INET6
 132         case AF_INET6:
 133                 afnumber = 6;
 134                 stat = &ipsec6stat;
 135                 break;
 136 #endif
 137         default:
 138                 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
 139                 return 0;       /* no change at all */
 140         }
 141
 142         /* grab parameters */
 143         algo = ipcomp_algorithm_lookup(sav->alg_enc);
 144         if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
 145                 IPSEC_STAT_INCREMENT(stat->out_inval);
 146                 m_freem(m);
 147                 return EINVAL;
 148         }
 149         if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
 150                 cpi = sav->alg_enc;
 151         else
 152                 cpi = ntohl(sav->spi) & 0xffff;
 153
 154         /* compute original payload length */
 155         plen = 0;
 156         for (n = md; n; n = n->m_next)
 157                 plen += n->m_len;
 158
 159         /* if the payload is short enough, we don't need to compress */
 160         if (plen < algo->minplen)
 161                 return 0;
 162
 163         /*
 164          * retain the original packet for two purposes:
 165          * (1) we need to backout our changes when compression is not necessary.
 166          * (2) byte lifetime computation should use the original packet.
 167          *     see RFC2401 page 23.
 168          * compromise two m_copym().  we will be going through every byte of
 169          * the payload during compression process anyways.
 170          */
 171         mcopy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 172         if (mcopy == NULL) {
 173                 error = ENOBUFS;
 174                 return 0;
 175         }
 176         md0 = m_copym(md, 0, M_COPYALL, M_NOWAIT);
 177         if (md0 == NULL) {
 178                 m_freem(mcopy);
 179                 error = ENOBUFS;
 180                 return 0;
 181         }
 182         plen0 = plen;
 183
 184         /* make the packet over-writable */
 185         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 186                 ;
 187         if (mprev == NULL || mprev->m_next != md) {
 188                 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
 189                     afnumber));
 190                 IPSEC_STAT_INCREMENT(stat->out_inval);
 191                 m_freem(m);
 192                 m_freem(md0);
 193                 m_freem(mcopy);
 194                 return EINVAL;
 195         }
 196         mprev->m_next = NULL;
 197         if ((md = ipsec_copypkt(md)) == NULL) {
 198                 m_freem(m);
 199                 m_freem(md0);
 200                 m_freem(mcopy);
 201                 error = ENOBUFS;
 202                 goto fail;
 203         }
 204         mprev->m_next = md;
 205
 206         /* compress data part */
 207         if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
 208                 ipseclog((LOG_ERR, "packet compression failure\n"));
 209                 m = NULL;
 210                 m_freem(md0);
 211                 m_freem(mcopy);
 212                 IPSEC_STAT_INCREMENT(stat->out_inval);
 213                 error = EINVAL;
 214                 goto fail;
 215         }
 216         IPSEC_STAT_INCREMENT(stat->out_comphist[sav->alg_enc]);
 217         md = mprev->m_next;
 218
 219         /*
 220          * if the packet became bigger, meaningless to use IPComp.
 221          * we've only wasted our cpu time.
 222          */
 223         if (plen0 < plen) {
 224                 m_freem(md);
 225                 m_freem(mcopy);
 226                 mprev->m_next = md0;
 227                 return 0;
 228         }
 229
 230         /*
 231          * no need to backout change beyond here.
 232          */
 233         m_freem(md0);
 234         md0 = NULL;
 235
 236         m->m_pkthdr.len -= plen0;
 237         m->m_pkthdr.len += plen;
 238
 239     {
 240         /*
 241          * insert IPComp header.
 242          */
 243 #if INET
 244         struct ip *ip = NULL;
 245 #endif
 246 #if INET6
 247         struct ip6_hdr *ip6 = NULL;
 248 #endif
 249         size_t hlen = 0;        /*ip header len*/
 250         size_t complen = sizeof(struct ipcomp);
 251
 252         switch (af) {
 253 #if INET
 254         case AF_INET:
 255                 ip = mtod(m, struct ip *);
 256 #ifdef _IP_VHL
 257                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 258 #else
 259                 hlen = ip->ip_hl << 2;
 260 #endif
 261                 break;
 262 #endif
 263 #if INET6
 264         case AF_INET6:
 265                 ip6 = mtod(m, struct ip6_hdr *);
 266                 hlen = sizeof(*ip6);
 267                 break;
 268 #endif
 269         }
 270
 271         compoff = m->m_pkthdr.len - plen;
 272
 273         /*
 274          * grow the mbuf to accomodate ipcomp header.
 275          * before: IP ... payload
 276          * after:  IP ... ipcomp payload
 277          */
 278         if (M_LEADINGSPACE(md) < complen) {
 279                 MGET(n, M_DONTWAIT, MT_DATA);
 280                 if (!n) {
 281                         m_freem(m);
 282                         error = ENOBUFS;
 283                         goto fail;
 284                 }
 285                 n->m_len = complen;
 286                 mprev->m_next = n;
 287                 n->m_next = md;
 288                 m->m_pkthdr.len += complen;
 289                 ipcomp = mtod(n, struct ipcomp *);
 290         } else {
 291                 md->m_len += complen;
 292                 md->m_data -= complen;
 293                 m->m_pkthdr.len += complen;
 294                 ipcomp = mtod(md, struct ipcomp *);
 295         }
 296
 297         bzero(ipcomp, sizeof(*ipcomp));
 298         ipcomp->comp_nxt = *nexthdrp;
 299         *nexthdrp = IPPROTO_IPCOMP;
 300         ipcomp->comp_cpi = htons(cpi);
 301         switch (af) {
 302 #if INET
 303         case AF_INET:
 304                 if (compoff + complen + plen < IP_MAXPACKET)
 305                         ip->ip_len = htons(compoff + complen + plen);
 306                 else {
 307                         ipseclog((LOG_ERR,
 308                             "IPv4 ESP output: size exceeds limit\n"));
 309                         IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 310                         m_freem(m);
 311                         error = EMSGSIZE;
 312                         goto fail;
 313                 }
 314                 break;
 315 #endif
 316 #if INET6
 317         case AF_INET6:
 318                 /* total packet length will be computed in ip6_output() */
 319                 break;
 320 #endif
 321         }
 322     }
 323
 324         if (!m) {
 325                 ipseclog((LOG_DEBUG,
 326                     "NULL mbuf after compression in ipcomp%d_output",
 327                     afnumber));
 328                 IPSEC_STAT_INCREMENT(stat->out_inval);
 329         }
 330                 IPSEC_STAT_INCREMENT(stat->out_success);
 331
 332         /* compute byte lifetime against original packet */
 333         key_sa_recordxfer(sav, mcopy);
 334         m_freem(mcopy);
 335
 336         return 0;
 337
 338 fail:
 339 #if 1
 340         return error;
 341 #else
 342         panic("something bad in ipcomp_output");
 343 #endif
 344 }
 345
 346 #if INET
 347 int
 348 ipcomp4_output(m, sav)
 349         struct mbuf *m;
 350         struct secasvar *sav;
 351 {
 352         struct ip *ip;
 353         if (m->m_len < sizeof(struct ip)) {
 354                 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
 355                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 356                 m_freem(m);
 357                 return 0;
 358         }
 359         ip = mtod(m, struct ip *);
 360         /* XXX assumes that m->m_next points to payload */
 361         return ipcomp_output(m, &ip->ip_p, m->m_next, AF_INET, sav);
 362 }
 363 #endif /*INET*/
 364
 365 #if INET6
 366 int
 367 ipcomp6_output(m, nexthdrp, md, sav)
 368         struct mbuf *m;
 369         u_char *nexthdrp;
 370         struct mbuf *md;
 371         struct secasvar *sav;
 372 {
 373         if (m->m_len < sizeof(struct ip6_hdr)) {
 374                 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
 375                 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 376                 m_freem(m);
 377                 return 0;
 378         }
 379         return ipcomp_output(m, nexthdrp, md, AF_INET6, sav);
 380 }
 381 #endif /*INET6*/