net/ipv4/esp4.c

   1 #include <linux/config.h>
   2 #include <linux/module.h>
   3 #include <net/inet_ecn.h>
   4 #include <net/ip.h>
   5 #include <net/xfrm.h>
   6 #include <net/esp.h>
   7 #include <asm/scatterlist.h>
   8 #include <linux/crypto.h>
   9 #include <linux/pfkeyv2.h>
  10 #include <linux/random.h>
  11 #include <net/icmp.h>
  12 #include <net/udp.h>
  13
  14 #define MAX_SG_ONSTACK 4
  15
  16 /* decapsulation data for use when post-processing */
  17 struct esp_decap_data {
  18         xfrm_address_t  saddr;
  19         __u16           sport;
  20         __u8            proto;
  21 };
  22
  23 int esp_output(struct sk_buff **pskb)
  24 {
  25         int err;
  26         struct dst_entry *dst = (*pskb)->dst;
  27         struct xfrm_state *x  = dst->xfrm;
  28         struct iphdr *iph, *top_iph;
  29         struct ip_esp_hdr *esph;
  30         struct crypto_tfm *tfm;
  31         struct esp_data *esp;
  32         struct sk_buff *trailer;
  33         struct udphdr *uh = NULL;
  34         u32 *udpdata32;
  35         struct xfrm_encap_tmpl *encap = NULL;
  36         int blksize;
  37         int clen;
  38         int alen;
  39         int nfrags;
  40         union {
  41                 struct iphdr    iph;
  42                 char            buf[60];
  43         } tmp_iph;
  44
  45         if ((*pskb)->ip_summed == CHECKSUM_HW) {
  46                 err = skb_checksum_help(pskb, 0);
  47                 if (err)
  48                         goto error_nolock;
  49         }
  50
  51         spin_lock_bh(&x->lock);
  52         err = xfrm_check_output(x, *pskb, AF_INET);
  53         if (err)
  54                 goto error;
  55         err = -ENOMEM;
  56
  57         /* Strip IP header in transport mode. Save it. */
  58         if (!x->props.mode) {
  59                 iph = (*pskb)->nh.iph;
  60                 memcpy(&tmp_iph, iph, iph->ihl*4);
  61                 __skb_pull(*pskb, iph->ihl*4);
  62         }
  63         /* Now skb is pure payload to encrypt */
  64
  65         /* Round to block size */
  66         clen = (*pskb)->len;
  67
  68         esp = x->data;
  69         alen = esp->auth.icv_trunc_len;
  70         tfm = esp->conf.tfm;
  71         blksize = (crypto_tfm_alg_blocksize(tfm) + 3) & ~3;
  72         clen = (clen + 2 + blksize-1)&~(blksize-1);
  73         if (esp->conf.padlen)
  74                 clen = (clen + esp->conf.padlen-1)&~(esp->conf.padlen-1);
  75
  76         if ((nfrags = skb_cow_data(*pskb, clen-(*pskb)->len+alen, &trailer)) < 0)
  77                 goto error;
  78
  79         /* Fill padding... */
  80         do {
  81                 int i;
  82                 for (i=0; i<clen-(*pskb)->len - 2; i++)
  83                         *(u8*)(trailer->tail + i) = i+1;
  84         } while (0);
  85         *(u8*)(trailer->tail + clen-(*pskb)->len - 2) = (clen - (*pskb)->len)-2;
  86         pskb_put(*pskb, trailer, clen - (*pskb)->len);
  87
  88         encap = x->encap;
  89
  90         iph = (*pskb)->nh.iph;
  91         if (x->props.mode) {
  92                 top_iph = (struct iphdr*)skb_push(*pskb, x->props.header_len);
  93                 esph = (struct ip_esp_hdr*)(top_iph+1);
  94                 if (encap && encap->encap_type) {
  95                         switch (encap->encap_type) {
  96                         case UDP_ENCAP_ESPINUDP:
  97                                 uh = (struct udphdr*) esph;
  98                                 esph = (struct ip_esp_hdr*)(uh+1);
  99                                 top_iph->protocol = IPPROTO_UDP;
 100                                 break;
 101                         case UDP_ENCAP_ESPINUDP_NON_IKE:
 102                                 uh = (struct udphdr*) esph;
 103                                 udpdata32 = (u32*)(uh+1);
 104                                 udpdata32[0] = udpdata32[1] = 0;
 105                                 esph = (struct ip_esp_hdr*)(udpdata32+2);
 106                                 alen += 2;
 107                                 top_iph->protocol = IPPROTO_UDP;
 108                                 break;
 109                         default:
 110                                 printk(KERN_INFO
 111                                        "esp_output(): Unhandled encap: %u\n",
 112                                        encap->encap_type);
 113                                 top_iph->protocol = IPPROTO_ESP;
 114                                 break;
 115                         }
 116                 } else
 117                         top_iph->protocol = IPPROTO_ESP;
 118                 *(u8*)(trailer->tail - 1) = IPPROTO_IPIP;
 119                 top_iph->ihl = 5;
 120                 top_iph->version = 4;
 121                 top_iph->tos = iph->tos;        /* DS disclosed */
 122                 if (x->props.flags & XFRM_STATE_NOECN)
 123                         IP_ECN_clear(top_iph);
 124                 top_iph->tot_len = htons((*pskb)->len + alen);
 125                 top_iph->frag_off = iph->frag_off&htons(IP_DF);
 126                 if (!(top_iph->frag_off))
 127                         ip_select_ident(top_iph, dst, 0);
 128                 top_iph->ttl = iph->ttl;        /* TTL disclosed */
 129                 top_iph->check = 0;
 130                 top_iph->saddr = x->props.saddr.a4;
 131                 top_iph->daddr = x->id.daddr.a4;
 132                 memset(&(IPCB(*pskb)->opt), 0, sizeof(struct ip_options));
 133         } else {
 134                 esph = (struct ip_esp_hdr*)skb_push(*pskb, x->props.header_len);
 135                 top_iph = (struct iphdr*)skb_push(*pskb, iph->ihl*4);
 136                 memcpy(top_iph, &tmp_iph, iph->ihl*4);
 137                 if (encap && encap->encap_type) {
 138                         switch (encap->encap_type) {
 139                         case UDP_ENCAP_ESPINUDP:
 140                                 uh = (struct udphdr*) esph;
 141                                 esph = (struct ip_esp_hdr*)(uh+1);
 142                                 top_iph->protocol = IPPROTO_UDP;
 143                                 break;
 144                         case UDP_ENCAP_ESPINUDP_NON_IKE:
 145                                 uh = (struct udphdr*) esph;
 146                                 udpdata32 = (u32*)(uh+1);
 147                                 udpdata32[0] = udpdata32[1] = 0;
 148                                 esph = (struct ip_esp_hdr*)(udpdata32+2);
 149                                 alen += 2;
 150                                 top_iph->protocol = IPPROTO_UDP;
 151                                 break;
 152                         default:
 153                                 printk(KERN_INFO
 154                                        "esp_output(): Unhandled encap: %u\n",
 155                                        encap->encap_type);
 156                                 top_iph->protocol = IPPROTO_ESP;
 157                                 break;
 158                         }
 159                 } else
 160                         top_iph->protocol = IPPROTO_ESP;
 161                 iph = &tmp_iph.iph;
 162                 top_iph->tot_len = htons((*pskb)->len + alen);
 163                 top_iph->check = 0;
 164                 top_iph->frag_off = iph->frag_off;
 165                 *(u8*)(trailer->tail - 1) = iph->protocol;
 166         }
 167
 168         /* this is non-NULL only with UDP Encapsulation */
 169         if (encap && uh) {
 170                 uh->source = encap->encap_sport;
 171                 uh->dest = encap->encap_dport;
 172                 uh->len = htons((*pskb)->len + alen - sizeof(struct iphdr));
 173                 uh->check = 0;
 174         }
 175
 176         esph->spi = x->id.spi;
 177         esph->seq_no = htonl(++x->replay.oseq);
 178
 179         if (esp->conf.ivlen)
 180                 crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
 181
 182         do {
 183                 struct scatterlist sgbuf[nfrags>MAX_SG_ONSTACK ? 0 : nfrags];
 184                 struct scatterlist *sg = sgbuf;
 185
 186                 if (unlikely(nfrags > MAX_SG_ONSTACK)) {
 187                         sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
 188                         if (!sg)
 189                                 goto error;
 190                 }
 191                 skb_to_sgvec(*pskb, sg, esph->enc_data+esp->conf.ivlen-(*pskb)->data, clen);
 192                 crypto_cipher_encrypt(tfm, sg, sg, clen);
 193                 if (unlikely(sg != sgbuf))
 194                         kfree(sg);
 195         } while (0);
 196
 197         if (esp->conf.ivlen) {
 198                 memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
 199                 crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
 200         }
 201
 202         if (esp->auth.icv_full_len) {
 203                 esp->auth.icv(esp, *pskb, (u8*)esph-(*pskb)->data,
 204                               sizeof(struct ip_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
 205                 pskb_put(*pskb, trailer, alen);
 206         }
 207
 208         ip_send_check(top_iph);
 209
 210         (*pskb)->nh.raw = (*pskb)->data;
 211
 212         x->curlft.bytes += (*pskb)->len;
 213         x->curlft.packets++;
 214         spin_unlock_bh(&x->lock);
 215         if (((*pskb)->dst = dst_pop(dst)) == NULL) {
 216                 err = -EHOSTUNREACH;
 217                 goto error_nolock;
 218         }
 219         return NET_XMIT_BYPASS;
 220
 221 error:
 222         spin_unlock_bh(&x->lock);
 223 error_nolock:
 224         kfree_skb(*pskb);
 225         return err;
 226 }
 227
 228 /*
 229  * Note: detecting truncated vs. non-truncated authentication data is very
 230  * expensive, so we only support truncated data, which is the recommended
 231  * and common case.
 232  */
 233 int esp_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
 234 {
 235         struct iphdr *iph;
 236         struct ip_esp_hdr *esph;
 237         struct esp_data *esp = x->data;
 238         struct sk_buff *trailer;
 239         int blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
 240         int alen = esp->auth.icv_trunc_len;
 241         int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
 242         int nfrags;
 243         int encap_len = 0;
 244
 245         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
 246                 goto out;
 247
 248         if (elen <= 0 || (elen & (blksize-1)))
 249                 goto out;
 250
 251         /* If integrity check is required, do this. */
 252         if (esp->auth.icv_full_len) {
 253                 u8 sum[esp->auth.icv_full_len];
 254                 u8 sum1[alen];
 255
 256                 esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
 257
 258                 if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
 259                         BUG();
 260
 261                 if (unlikely(memcmp(sum, sum1, alen))) {
 262                         x->stats.integrity_failed++;
 263                         goto out;
 264                 }
 265         }
 266
 267         if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
 268                 goto out;
 269
 270         skb->ip_summed = CHECKSUM_NONE;
 271
 272         esph = (struct ip_esp_hdr*)skb->data;
 273         iph = skb->nh.iph;
 274
 275         /* Get ivec. This can be wrong, check against another impls. */
 276         if (esp->conf.ivlen)
 277                 crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm));
 278
 279         {
 280                 u8 nexthdr[2];
 281                 struct scatterlist sgbuf[nfrags>MAX_SG_ONSTACK ? 0 : nfrags];
 282                 struct scatterlist *sg = sgbuf;
 283                 u8 workbuf[60];
 284                 int padlen;
 285
 286                 if (unlikely(nfrags > MAX_SG_ONSTACK)) {
 287                         sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
 288                         if (!sg)
 289                                 goto out;
 290                 }
 291                 skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
 292                 crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen);
 293                 if (unlikely(sg != sgbuf))
 294                         kfree(sg);
 295
 296                 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
 297                         BUG();
 298
 299                 padlen = nexthdr[0];
 300                 if (padlen+2 >= elen)
 301                         goto out;
 302
 303                 /* ... check padding bits here. Silly. :-) */
 304
 305                 if (x->encap && decap && decap->decap_type) {
 306                         struct esp_decap_data *encap_data;
 307                         struct udphdr *uh = (struct udphdr *) (iph+1);
 308
 309                         encap_data = (struct esp_decap_data *) (decap->decap_data);
 310                         encap_data->proto = 0;
 311
 312                         switch (decap->decap_type) {
 313                         case UDP_ENCAP_ESPINUDP:
 314                         case UDP_ENCAP_ESPINUDP_NON_IKE:
 315
 316                                 if ((void*)uh == (void*)esph) {
 317                                         printk(KERN_DEBUG
 318                                                "esp_input(): Got ESP; expecting ESPinUDP\n");
 319                                         break;
 320                                 }
 321
 322                                 encap_data->proto = AF_INET;
 323                                 encap_data->saddr.a4 = iph->saddr;
 324                                 encap_data->sport = uh->source;
 325                                 encap_len = (void*)esph - (void*)uh;
 326                                 if (encap_len != sizeof(*uh))
 327                                   printk(KERN_DEBUG
 328                                          "esp_input(): UDP -> ESP: too much room: %d\n",
 329                                          encap_len);
 330                                 break;
 331
 332                         default:
 333                                 printk(KERN_INFO
 334                                "esp_input(): processing unknown encap type: %u\n",
 335                                        decap->decap_type);
 336                                 break;
 337                         }
 338                 }
 339
 340                 iph->protocol = nexthdr[1];
 341                 pskb_trim(skb, skb->len - alen - padlen - 2);
 342                 memcpy(workbuf, skb->nh.raw, iph->ihl*4);
 343                 skb->h.raw = skb_pull(skb, sizeof(struct ip_esp_hdr) + esp->conf.ivlen);
 344                 skb->nh.raw += encap_len + sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
 345                 memcpy(skb->nh.raw, workbuf, iph->ihl*4);
 346                 skb->nh.iph->tot_len = htons(skb->len);
 347         }
 348
 349         return 0;
 350
 351 out:
 352         return -EINVAL;
 353 }
 354
 355 int esp_post_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
 356 {
 357
 358         if (x->encap) {
 359                 struct xfrm_encap_tmpl *encap;
 360                 struct esp_decap_data *decap_data;
 361
 362                 encap = x->encap;
 363                 decap_data = (struct esp_decap_data *)(decap->decap_data);
 364
 365                 /* first, make sure that the decap type == the encap type */
 366                 if (encap->encap_type != decap->decap_type)
 367                         return -EINVAL;
 368
 369                 /* Next, if we don't have an encap type, then ignore it */
 370                 if (!encap->encap_type)
 371                         return 0;
 372
 373                 switch (encap->encap_type) {
 374                 case UDP_ENCAP_ESPINUDP:
 375                 case UDP_ENCAP_ESPINUDP_NON_IKE:
 376                         /*
 377                          * 1) if the NAT-T peer's IP or port changed then
 378                          *    advertize the change to the keying daemon.
 379                          *    This is an inbound SA, so just compare
 380                          *    SRC ports.
 381                          */
 382                         if (decap_data->proto == AF_INET &&
 383                             (decap_data->saddr.a4 != x->props.saddr.a4 ||
 384                              decap_data->sport != encap->encap_sport)) {
 385                                 xfrm_address_t ipaddr;
 386
 387                                 ipaddr.a4 = decap_data->saddr.a4;
 388                                 km_new_mapping(x, &ipaddr, decap_data->sport);
 389
 390                                 /* XXX: perhaps add an extra
 391                                  * policy check here, to see
 392                                  * if we should allow or
 393                                  * reject a packet from a
 394                                  * different source
 395                                  * address/port.
 396                                  */
 397                         }
 398
 399                         /*
 400                          * 2) ignore UDP/TCP checksums in case
 401                          *    of NAT-T in Transport Mode, or
 402                          *    perform other post-processing fixes
 403                          *    as per * draft-ietf-ipsec-udp-encaps-06,
 404                          *    section 3.1.2
 405                          */
 406                         if (!x->props.mode)
 407                                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 408
 409                         break;
 410                 default:
 411                         printk(KERN_INFO
 412                                "esp4_post_input(): Unhandled encap type: %u\n",
 413                                encap->encap_type);
 414                         break;
 415                 }
 416         }
 417         return 0;
 418 }
 419
 420 static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
 421 {
 422         struct esp_data *esp = x->data;
 423         u32 blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
 424
 425         if (x->props.mode) {
 426                 mtu = (mtu + 2 + blksize-1)&~(blksize-1);
 427         } else {
 428                 /* The worst case. */
 429                 mtu += 2 + blksize;
 430         }
 431         if (esp->conf.padlen)
 432                 mtu = (mtu + esp->conf.padlen-1)&~(esp->conf.padlen-1);
 433
 434         return mtu + x->props.header_len + esp->auth.icv_trunc_len;
 435 }
 436
 437 void esp4_err(struct sk_buff *skb, u32 info)
 438 {
 439         struct iphdr *iph = (struct iphdr*)skb->data;
 440         struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
 441         struct xfrm_state *x;
 442
 443         if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
 444             skb->h.icmph->code != ICMP_FRAG_NEEDED)
 445                 return;
 446
 447         x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
 448         if (!x)
 449                 return;
 450         NETDEBUG(printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
 451                         ntohl(esph->spi), ntohl(iph->daddr)));
 452         xfrm_state_put(x);
 453 }
 454
 455 void esp_destroy(struct xfrm_state *x)
 456 {
 457         struct esp_data *esp = x->data;
 458
 459         if (!esp)
 460                 return;
 461
 462         if (esp->conf.tfm) {
 463                 crypto_free_tfm(esp->conf.tfm);
 464                 esp->conf.tfm = NULL;
 465         }
 466         if (esp->conf.ivec) {
 467                 kfree(esp->conf.ivec);
 468                 esp->conf.ivec = NULL;
 469         }
 470         if (esp->auth.tfm) {
 471                 crypto_free_tfm(esp->auth.tfm);
 472                 esp->auth.tfm = NULL;
 473         }
 474         if (esp->auth.work_icv) {
 475                 kfree(esp->auth.work_icv);
 476                 esp->auth.work_icv = NULL;
 477         }
 478         kfree(esp);
 479 }
 480
 481 int esp_init_state(struct xfrm_state *x, void *args)
 482 {
 483         struct esp_data *esp = NULL;
 484
 485         /* null auth and encryption can have zero length keys */
 486         if (x->aalg) {
 487                 if (x->aalg->alg_key_len > 512)
 488                         goto error;
 489         }
 490         if (x->ealg == NULL)
 491                 goto error;
 492
 493         esp = kmalloc(sizeof(*esp), GFP_KERNEL);
 494         if (esp == NULL)
 495                 return -ENOMEM;
 496
 497         memset(esp, 0, sizeof(*esp));
 498
 499         if (x->aalg) {
 500                 struct xfrm_algo_desc *aalg_desc;
 501
 502                 esp->auth.key = x->aalg->alg_key;
 503                 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
 504                 esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
 505                 if (esp->auth.tfm == NULL)
 506                         goto error;
 507                 esp->auth.icv = esp_hmac_digest;
 508
 509                 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name);
 510                 BUG_ON(!aalg_desc);
 511
 512                 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
 513                     crypto_tfm_alg_digestsize(esp->auth.tfm)) {
 514                         NETDEBUG(printk(KERN_INFO "ESP: %s digestsize %u != %hu\n",
 515                                x->aalg->alg_name,
 516                                crypto_tfm_alg_digestsize(esp->auth.tfm),
 517                                aalg_desc->uinfo.auth.icv_fullbits/8));
 518                         goto error;
 519                 }
 520
 521                 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
 522                 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
 523
 524                 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
 525                 if (!esp->auth.work_icv)
 526                         goto error;
 527         }
 528         esp->conf.key = x->ealg->alg_key;
 529         esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
 530         if (x->props.ealgo == SADB_EALG_NULL)
 531                 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB);
 532         else
 533                 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC);
 534         if (esp->conf.tfm == NULL)
 535                 goto error;
 536         esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm);
 537         esp->conf.padlen = 0;
 538         if (esp->conf.ivlen) {
 539                 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
 540                 if (unlikely(esp->conf.ivec == NULL))
 541                         goto error;
 542                 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
 543         }
 544         crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len);
 545         x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
 546         if (x->props.mode)
 547                 x->props.header_len += sizeof(struct iphdr);
 548         if (x->encap) {
 549                 struct xfrm_encap_tmpl *encap = x->encap;
 550
 551                 if (encap->encap_type) {
 552                         switch (encap->encap_type) {
 553                         case UDP_ENCAP_ESPINUDP:
 554                                 x->props.header_len += sizeof(struct udphdr);
 555                                 break;
 556                         case UDP_ENCAP_ESPINUDP_NON_IKE:
 557                                 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
 558                                 break;
 559                         default:
 560                                 printk (KERN_INFO
 561                                 "esp_init_state(): Unhandled encap type: %u\n",
 562                                         encap->encap_type);
 563                                 break;
 564                         }
 565                 }
 566         }
 567         x->data = esp;
 568         x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
 569         return 0;
 570
 571 error:
 572         if (esp) {
 573                 if (esp->auth.tfm)
 574                         crypto_free_tfm(esp->auth.tfm);
 575                 if (esp->auth.work_icv)
 576                         kfree(esp->auth.work_icv);
 577                 if (esp->conf.tfm)
 578                         crypto_free_tfm(esp->conf.tfm);
 579                 kfree(esp);
 580         }
 581         return -EINVAL;
 582 }
 583
 584 static struct xfrm_type esp_type =
 585 {
 586         .description    = "ESP4",
 587         .owner          = THIS_MODULE,
 588         .proto          = IPPROTO_ESP,
 589         .init_state     = esp_init_state,
 590         .destructor     = esp_destroy,
 591         .get_max_size   = esp4_get_max_size,
 592         .input          = esp_input,
 593         .post_input     = esp_post_input,
 594         .output         = esp_output
 595 };
 596
 597 static struct inet_protocol esp4_protocol = {
 598         .handler        =       xfrm4_rcv,
 599         .err_handler    =       esp4_err,
 600         .no_policy      =       1,
 601 };
 602
 603 static int __init esp4_init(void)
 604 {
 605         struct xfrm_decap_state decap;
 606
 607         if (sizeof(struct esp_decap_data)  <
 608             sizeof(decap.decap_data)) {
 609                 extern void decap_data_too_small(void);
 610
 611                 decap_data_too_small();
 612         }
 613
 614         if (xfrm_register_type(&esp_type, AF_INET) < 0) {
 615                 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
 616                 return -EAGAIN;
 617         }
 618         if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
 619                 printk(KERN_INFO "ip esp init: can't add protocol\n");
 620                 xfrm_unregister_type(&esp_type, AF_INET);
 621                 return -EAGAIN;
 622         }
 623         return 0;
 624 }
 625
 626 static void __exit esp4_fini(void)
 627 {
 628         if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
 629                 printk(KERN_INFO "ip esp close: can't remove protocol\n");
 630         if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
 631                 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
 632 }
 633
 634 module_init(esp4_init);
 635 module_exit(esp4_fini);
 636 MODULE_LICENSE("GPL");