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