sys/netinet6/ipcomp_output.c

   1 /*      $NetBSD: ipcomp_output.c,v 1.28 2008/05/05 13:41:30 ad Exp $    */
   2 /*      $KAME: ipcomp_output.c,v 1.24 2001/07/26 06:53:18 jinmei 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 <sys/cdefs.h>
  38 __KERNEL_RCSID(0, "$NetBSD: ipcomp_output.c,v 1.28 2008/05/05 13:41:30 ad Exp $");
  39
  40 #include "opt_inet.h"
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/malloc.h>
  45 #include <sys/mbuf.h>
  46 #include <sys/domain.h>
  47 #include <sys/protosw.h>
  48 #include <sys/socket.h>
  49 #include <sys/errno.h>
  50 #include <sys/time.h>
  51 #include <sys/kernel.h>
  52 #include <sys/syslog.h>
  53
  54 #include <net/if.h>
  55 #include <net/route.h>
  56 #include <net/netisr.h>
  57 #include <net/zlib.h>
  58 #include <sys/cpu.h>
  59
  60 #include <netinet/in.h>
  61 #include <netinet/in_systm.h>
  62 #include <netinet/in_var.h>
  63 #include <netinet/ip.h>
  64 #include <netinet/ip_var.h>
  65 #include <netinet/ip_ecn.h>
  66
  67 #ifdef INET6
  68 #include <netinet/ip6.h>
  69 #include <netinet6/ip6_var.h>
  70 #endif
  71 #include <netinet6/ipcomp.h>
  72
  73 #include <netinet6/ipsec.h>
  74 #include <netinet6/ipsec_private.h>
  75 #include <netkey/key.h>
  76 #include <netkey/keydb.h>
  77
  78 #include <machine/stdarg.h>
  79
  80 #include <net/net_osdep.h>
  81
  82 static int ipcomp_output(struct mbuf *, u_char *, struct mbuf *,
  83         struct ipsecrequest *, int);
  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(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
 105         struct ipsecrequest *isr, int af)
 106 {
 107         struct mbuf *n;
 108         struct mbuf *md0;
 109         struct mbuf *mcopy;
 110         struct mbuf *mprev;
 111         struct ipcomp *ipcomp;
 112         struct secasvar *sav = isr->sav;
 113         const struct ipcomp_algorithm *algo;
 114         u_int16_t cpi;          /* host order */
 115         size_t plen0, plen;     /* payload length to be compressed */
 116         size_t compoff;
 117         int afnumber;
 118         int error = 0;
 119         percpu_t *stat;
 120
 121         switch (af) {
 122 #ifdef INET
 123         case AF_INET:
 124                 afnumber = 4;
 125                 stat = ipsecstat_percpu;
 126                 break;
 127 #endif
 128 #ifdef INET6
 129         case AF_INET6:
 130                 afnumber = 6;
 131                 stat = ipsec6stat_percpu;
 132                 break;
 133 #endif
 134         default:
 135                 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
 136                 return 0;       /* no change at all */
 137         }
 138
 139         /* grab parameters */
 140         algo = ipcomp_algorithm_lookup(sav->alg_enc);
 141         if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
 142                 _NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
 143                 error = EINVAL;
 144                 goto fail1;
 145         }
 146         if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
 147                 cpi = sav->alg_enc;
 148         else
 149                 cpi = ntohl(sav->spi) & 0xffff;
 150
 151         /* compute original payload length */
 152         plen = 0;
 153         for (n = md; n; n = n->m_next)
 154                 plen += n->m_len;
 155
 156         /* if the payload is short enough, we don't need to compress */
 157         if (plen < algo->minplen)
 158                 return 0;
 159
 160         /*
 161          * retain the original packet for two purposes:
 162          * (1) we need to backout our changes when compression is not necessary.
 163          * (2) byte lifetime computation should use the original packet.
 164          *     see RFC2401 page 23.
 165          * compromise two m_copym().  we will be going through every byte of
 166          * the payload during compression process anyways.
 167          */
 168         mcopy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 169         if (mcopy == NULL) {
 170                 error = ENOBUFS;
 171                 goto fail1;
 172         }
 173         md0 = m_copym(md, 0, M_COPYALL, M_NOWAIT);
 174         if (md0 == NULL) {
 175                 error = ENOBUFS;
 176                 goto fail2;
 177         }
 178         plen0 = plen;
 179
 180         /* make the packet over-writable */
 181         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 182                 ;
 183         if (mprev == NULL || mprev->m_next != md) {
 184                 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
 185                     afnumber));
 186                 _NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
 187                 error = EINVAL;
 188                 goto fail3;
 189         }
 190         mprev->m_next = NULL;
 191         if ((md = ipsec_copypkt(md)) == NULL) {
 192                 error = ENOBUFS;
 193                 goto fail3;
 194         }
 195         mprev->m_next = md;
 196
 197         /* compress data part */
 198         if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
 199                 ipseclog((LOG_ERR, "packet compression failure\n"));
 200                 m = NULL;
 201                 _NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
 202                 error = EINVAL;
 203                 goto fail3;
 204         }
 205         _NET_STATINC(stat, IPSEC_STAT_OUT_COMPHIST + sav->alg_enc);
 206         md = mprev->m_next;
 207
 208         /*
 209          * if the packet became bigger, meaningless to use IPComp.
 210          * we've only wasted our CPU time.
 211          */
 212         if (plen0 < plen) {
 213                 m_freem(md);
 214                 m_freem(mcopy);
 215                 mprev->m_next = md0;
 216                 return 0;
 217         }
 218
 219         /*
 220          * no need to backout change beyond here.
 221          */
 222         m_freem(md0);
 223         md0 = NULL;
 224
 225         m->m_pkthdr.len -= plen0;
 226         m->m_pkthdr.len += plen;
 227
 228     {
 229         /*
 230          * insert IPComp header.
 231          */
 232 #ifdef INET
 233         struct ip *ip = NULL;
 234 #endif
 235 #ifdef INET6
 236         struct ip6_hdr *ip6 = NULL;
 237 #endif
 238         size_t hlen = 0;        /* ip header len */
 239         size_t complen = sizeof(struct ipcomp);
 240
 241         switch (af) {
 242 #ifdef INET
 243         case AF_INET:
 244                 ip = mtod(m, struct ip *);
 245                 hlen = ip->ip_hl << 2;
 246                 break;
 247 #endif
 248 #ifdef INET6
 249         case AF_INET6:
 250                 ip6 = mtod(m, struct ip6_hdr *);
 251                 hlen = sizeof(*ip6);
 252                 break;
 253 #endif
 254         }
 255
 256         compoff = m->m_pkthdr.len - plen;
 257
 258         /*
 259          * grow the mbuf to accommodate ipcomp header.
 260          * before: IP ... payload
 261          * after:  IP ... ipcomp payload
 262          */
 263         if (M_LEADINGSPACE(md) < complen) {
 264                 MGET(n, M_DONTWAIT, MT_DATA);
 265                 if (!n) {
 266                         error = ENOBUFS;
 267                         goto fail2;
 268                 }
 269                 n->m_len = complen;
 270                 mprev->m_next = n;
 271                 n->m_next = md;
 272                 m->m_pkthdr.len += complen;
 273                 ipcomp = mtod(n, struct ipcomp *);
 274         } else {
 275                 md->m_len += complen;
 276                 md->m_data -= complen;
 277                 m->m_pkthdr.len += complen;
 278                 ipcomp = mtod(md, struct ipcomp *);
 279         }
 280
 281         memset(ipcomp, 0, sizeof(*ipcomp));
 282         ipcomp->comp_nxt = *nexthdrp;
 283         *nexthdrp = IPPROTO_IPCOMP;
 284         ipcomp->comp_cpi = htons(cpi);
 285         switch (af) {
 286 #ifdef INET
 287         case AF_INET:
 288                 if (compoff + complen + plen < IP_MAXPACKET)
 289                         ip->ip_len = htons(compoff + complen + plen);
 290                 else {
 291                         ipseclog((LOG_ERR,
 292                             "IPv4 ESP output: size exceeds limit\n"));
 293                         IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
 294                         error = EMSGSIZE;
 295                         goto fail2;
 296                 }
 297                 break;
 298 #endif
 299 #ifdef INET6
 300         case AF_INET6:
 301                 /* total packet length will be computed in ip6_output() */
 302                 break;
 303 #endif
 304         }
 305     }
 306
 307         if (!m) {
 308                 ipseclog((LOG_DEBUG,
 309                     "NULL mbuf after compression in ipcomp%d_output",
 310                     afnumber));
 311                 _NET_STATINC(stat, IPSEC_STAT_OUT_INVAL);
 312         }
 313                 _NET_STATINC(stat, IPSEC_STAT_OUT_SUCCESS);
 314
 315         /* compute byte lifetime against original packet */
 316         key_sa_recordxfer(sav, mcopy);
 317         m_freem(mcopy);
 318
 319         return 0;
 320
 321 fail3:
 322         m_freem(md0);
 323 fail2:
 324         m_freem(mcopy);
 325 fail1:
 326         m_freem(m);
 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                 IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
 342                 m_freem(m);
 343                 return EINVAL;
 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                 IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL);
 359                 m_freem(m);
 360                 return EINVAL;
 361         }
 362         return ipcomp_output(m, nexthdrp, md, isr, AF_INET6);
 363 }
 364 #endif /* INET6 */