sys/netinet6/ipcomp_output.c

   1 /*      $FreeBSD: src/sys/netinet6/ipcomp_output.c,v 1.1.2.4 2003/04/29 08:33:50 suz Exp $      */
   2 /*      $KAME: ipcomp_output.c,v 1.25 2002/06/09 14:44:00 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 #include "opt_inet.h"
  38 #include "opt_inet6.h"
  39
  40 #include <sys/param.h>
  41 #include <sys/systm.h>
  42 #include <sys/malloc.h>
  43 #include <sys/mbuf.h>
  44 #include <sys/domain.h>
  45 #include <sys/protosw.h>
  46 #include <sys/socket.h>
  47 #include <sys/errno.h>
  48 #include <sys/time.h>
  49 #include <sys/syslog.h>
  50
  51 #include <net/if.h>
  52 #include <net/route.h>
  53 #include <net/netisr.h>
  54 #include <machine/cpu.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 #ifdef INET6
  64 #include <netinet/ip6.h>
  65 #include <netinet6/ip6_var.h>
  66 #endif
  67 #include <netinet6/ipcomp.h>
  68 #ifdef INET6
  69 #include <netinet6/ipcomp6.h>
  70 #endif
  71
  72 #include <netinet6/ipsec.h>
  73 #ifdef INET6
  74 #include <netinet6/ipsec6.h>
  75 #endif
  76 #include <netproto/key/key.h>
  77 #include <netproto/key/keydb.h>
  78
  79 #include <machine/stdarg.h>
  80
  81 #include <net/net_osdep.h>
  82
  83 static int ipcomp_output (struct mbuf *, u_char *, struct mbuf *,
  84         struct ipsecrequest *, int);
  85
  86 /*
  87  * Modify the packet so that the payload is compressed.
  88  * The mbuf (m) must start with IPv4 or IPv6 header.
  89  * On failure, free the given mbuf and return non-zero.
  90  *
  91  * on invocation:
  92  *      m   nexthdrp md
  93  *      v   v        v
  94  *      IP ......... payload
  95  * during the encryption:
  96  *      m   nexthdrp mprev md
  97  *      v   v        v     v
  98  *      IP ............... ipcomp payload
  99  *                         <-----><----->
 100  *                         complen  plen
 101  *      <-> hlen
 102  *      <-----------------> compoff
 103  */
 104 static int
 105 ipcomp_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
 106               struct ipsecrequest *isr, int af)
 107 {
 108         struct mbuf *n;
 109         struct mbuf *md0;
 110         struct mbuf *mcopy;
 111         struct mbuf *mprev;
 112         struct ipcomp *ipcomp;
 113         struct secasvar *sav = isr->sav;
 114         const struct ipcomp_algorithm *algo;
 115         u_int16_t cpi;          /* host order */
 116         size_t plen0, plen;     /* payload length to be compressed */
 117         size_t compoff;
 118         int afnumber;
 119         int error = 0;
 120         struct ipsecstat *stat;
 121
 122         switch (af) {
 123 #ifdef INET
 124         case AF_INET:
 125                 afnumber = 4;
 126                 stat = &ipsecstat;
 127                 break;
 128 #endif
 129 #ifdef INET6
 130         case AF_INET6:
 131                 afnumber = 6;
 132                 stat = &ipsec6stat;
 133                 break;
 134 #endif
 135         default:
 136                 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
 137                 return 0;       /* no change at all */
 138         }
 139
 140         /* grab parameters */
 141         algo = ipcomp_algorithm_lookup(sav->alg_enc);
 142         if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
 143                 stat->out_inval++;
 144                 m_freem(m);
 145                 return EINVAL;
 146         }
 147         if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
 148                 cpi = sav->alg_enc;
 149         else
 150                 cpi = ntohl(sav->spi) & 0xffff;
 151
 152         /* compute original payload length */
 153         plen = 0;
 154         for (n = md; n; n = n->m_next)
 155                 plen += n->m_len;
 156
 157         /* if the payload is short enough, we don't need to compress */
 158         if (plen < algo->minplen)
 159                 return 0;
 160
 161         /*
 162          * retain the original packet for two purposes:
 163          * (1) we need to backout our changes when compression is not necessary.
 164          * (2) byte lifetime computation should use the original packet.
 165          *     see RFC2401 page 23.
 166          * compromise two m_copym().  we will be going through every byte of
 167          * the payload during compression process anyways.
 168          */
 169         mcopy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 170         if (mcopy == NULL) {
 171                 error = ENOBUFS;
 172                 return 0;
 173         }
 174         md0 = m_copym(md, 0, M_COPYALL, M_NOWAIT);
 175         if (md0 == NULL) {
 176                 m_freem(mcopy);
 177                 error = ENOBUFS;
 178                 return 0;
 179         }
 180         plen0 = plen;
 181
 182         /* make the packet over-writable */
 183         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 184                 ;
 185         if (mprev == NULL || mprev->m_next != md) {
 186                 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
 187                     afnumber));
 188                 stat->out_inval++;
 189                 m_freem(m);
 190                 m_freem(md0);
 191                 m_freem(mcopy);
 192                 return EINVAL;
 193         }
 194         mprev->m_next = NULL;
 195         if ((md = ipsec_copypkt(md)) == NULL) {
 196                 m_freem(m);
 197                 m_freem(md0);
 198                 m_freem(mcopy);
 199                 error = ENOBUFS;
 200                 goto fail;
 201         }
 202         mprev->m_next = md;
 203
 204         /* compress data part */
 205         if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
 206                 ipseclog((LOG_ERR, "packet compression failure\n"));
 207                 m = NULL;
 208                 m_freem(md0);
 209                 m_freem(mcopy);
 210                 stat->out_inval++;
 211                 error = EINVAL;
 212                 goto fail;
 213         }
 214         stat->out_comphist[sav->alg_enc]++;
 215         md = mprev->m_next;
 216
 217         /*
 218          * if the packet became bigger, meaningless to use IPComp.
 219          * we've only wasted our cpu time.
 220          */
 221         if (plen0 < plen) {
 222                 m_freem(md);
 223                 m_freem(mcopy);
 224                 mprev->m_next = md0;
 225                 return 0;
 226         }
 227
 228         /*
 229          * no need to backout change beyond here.
 230          */
 231         m_freem(md0);
 232         md0 = NULL;
 233
 234         m->m_pkthdr.len -= plen0;
 235         m->m_pkthdr.len += plen;
 236
 237     {
 238         /*
 239          * insert IPComp header.
 240          */
 241 #ifdef INET
 242         struct ip *ip = NULL;
 243 #endif
 244         size_t complen = sizeof(struct ipcomp);
 245
 246         switch (af) {
 247 #ifdef INET
 248         case AF_INET:
 249                 ip = mtod(m, struct ip *);
 250                 break;
 251 #endif
 252 #ifdef INET6
 253         case AF_INET6:
 254                 break;
 255 #endif
 256         }
 257
 258         compoff = m->m_pkthdr.len - plen;
 259
 260         /*
 261          * grow the mbuf to accomodate ipcomp header.
 262          * before: IP ... payload
 263          * after:  IP ... ipcomp payload
 264          */
 265         if (M_LEADINGSPACE(md) < complen) {
 266                 MGET(n, M_NOWAIT, MT_DATA);
 267                 if (!n) {
 268                         m_freem(m);
 269                         error = ENOBUFS;
 270                         goto fail;
 271                 }
 272                 n->m_len = complen;
 273                 mprev->m_next = n;
 274                 n->m_next = md;
 275                 m->m_pkthdr.len += complen;
 276                 ipcomp = mtod(n, struct ipcomp *);
 277         } else {
 278                 md->m_len += complen;
 279                 md->m_data -= complen;
 280                 m->m_pkthdr.len += complen;
 281                 ipcomp = mtod(md, struct ipcomp *);
 282         }
 283
 284         bzero(ipcomp, sizeof(*ipcomp));
 285         ipcomp->comp_nxt = *nexthdrp;
 286         *nexthdrp = IPPROTO_IPCOMP;
 287         ipcomp->comp_cpi = htons(cpi);
 288         switch (af) {
 289 #ifdef INET
 290         case AF_INET:
 291                 if (compoff + complen + plen < IP_MAXPACKET)
 292                         ip->ip_len = htons(compoff + complen + plen);
 293                 else {
 294                         ipseclog((LOG_ERR,
 295                             "IPv4 ESP output: size exceeds limit\n"));
 296                         ipsecstat.out_inval++;
 297                         m_freem(m);
 298                         error = EMSGSIZE;
 299                         goto fail;
 300                 }
 301                 break;
 302 #endif
 303 #ifdef INET6
 304         case AF_INET6:
 305                 /* total packet length will be computed in ip6_output() */
 306                 break;
 307 #endif
 308         }
 309     }
 310
 311         if (!m) {
 312                 ipseclog((LOG_DEBUG,
 313                     "NULL mbuf after compression in ipcomp%d_output",
 314                     afnumber));
 315                 stat->out_inval++;
 316         }
 317                 stat->out_success++;
 318
 319         /* compute byte lifetime against original packet */
 320         key_sa_recordxfer(sav, mcopy);
 321         m_freem(mcopy);
 322
 323         return 0;
 324
 325 fail:
 326 #if 1
 327         return error;
 328 #else
 329         panic("something bad in ipcomp_output");
 330 #endif
 331 }
 332
 333 #ifdef INET
 334 int
 335 ipcomp4_output(struct mbuf *m, struct ipsecrequest *isr)
 336 {
 337         struct ip *ip;
 338         if (m->m_len < sizeof(struct ip)) {
 339                 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
 340                 ipsecstat.out_inval++;
 341                 m_freem(m);
 342                 return 0;
 343         }
 344         ip = mtod(m, struct ip *);
 345         /* XXX assumes that m->m_next points to payload */
 346         return ipcomp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
 347 }
 348 #endif /* INET */
 349
 350 #ifdef INET6
 351 int
 352 ipcomp6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
 353                struct ipsecrequest *isr)
 354 {
 355         if (m->m_len < sizeof(struct ip6_hdr)) {
 356                 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
 357                 ipsec6stat.out_inval++;
 358                 m_freem(m);
 359                 return 0;
 360         }
 361         return ipcomp_output(m, nexthdrp, md, isr, AF_INET6);
 362 }
 363 #endif /* INET6 */