net/ipv6/esp6.c

   1 /*
   2  * Copyright (C)2002 USAGI/WIDE Project
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  *
  18  * Authors
  19  *
  20  *      Mitsuru KANDA @USAGI       : IPv6 Support
  21  *      Kazunori MIYAZAWA @USAGI   :
  22  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
  23  *
  24  *      This file is derived from net/ipv4/esp.c
  25  */
  26
  27 #include <crypto/aead.h>
  28 #include <crypto/authenc.h>
  29 #include <linux/err.h>
  30 #include <linux/module.h>
  31 #include <net/ip.h>
  32 #include <net/xfrm.h>
  33 #include <net/esp.h>
  34 #include <linux/scatterlist.h>
  35 #include <linux/kernel.h>
  36 #include <linux/pfkeyv2.h>
  37 #include <linux/random.h>
  38 #include <linux/slab.h>
  39 #include <linux/spinlock.h>
  40 #include <net/icmp.h>
  41 #include <net/ipv6.h>
  42 #include <net/protocol.h>
  43 #include <linux/icmpv6.h>
  44
  45 struct esp_skb_cb {
  46         struct xfrm_skb_cb xfrm;
  47         void *tmp;
  48 };
  49
  50 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
  51
  52 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
  53
  54 /*
  55  * Allocate an AEAD request structure with extra space for SG and IV.
  56  *
  57  * For alignment considerations the upper 32 bits of the sequence number are
  58  * placed at the front, if present. Followed by the IV, the request and finally
  59  * the SG list.
  60  *
  61  * TODO: Use spare space in skb for this where possible.
  62  */
  63 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
  64 {
  65         unsigned int len;
  66
  67         len = seqihlen;
  68
  69         len += crypto_aead_ivsize(aead);
  70
  71         if (len) {
  72                 len += crypto_aead_alignmask(aead) &
  73                        ~(crypto_tfm_ctx_alignment() - 1);
  74                 len = ALIGN(len, crypto_tfm_ctx_alignment());
  75         }
  76
  77         len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
  78         len = ALIGN(len, __alignof__(struct scatterlist));
  79
  80         len += sizeof(struct scatterlist) * nfrags;
  81
  82         return kmalloc(len, GFP_ATOMIC);
  83 }
  84
  85 static inline __be32 *esp_tmp_seqhi(void *tmp)
  86 {
  87         return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
  88 }
  89
  90 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
  91 {
  92         return crypto_aead_ivsize(aead) ?
  93                PTR_ALIGN((u8 *)tmp + seqhilen,
  94                          crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
  95 }
  96
  97 static inline struct aead_givcrypt_request *esp_tmp_givreq(
  98         struct crypto_aead *aead, u8 *iv)
  99 {
 100         struct aead_givcrypt_request *req;
 101
 102         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
 103                                 crypto_tfm_ctx_alignment());
 104         aead_givcrypt_set_tfm(req, aead);
 105         return req;
 106 }
 107
 108 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
 109 {
 110         struct aead_request *req;
 111
 112         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
 113                                 crypto_tfm_ctx_alignment());
 114         aead_request_set_tfm(req, aead);
 115         return req;
 116 }
 117
 118 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
 119                                              struct aead_request *req)
 120 {
 121         return (void *)ALIGN((unsigned long)(req + 1) +
 122                              crypto_aead_reqsize(aead),
 123                              __alignof__(struct scatterlist));
 124 }
 125
 126 static inline struct scatterlist *esp_givreq_sg(
 127         struct crypto_aead *aead, struct aead_givcrypt_request *req)
 128 {
 129         return (void *)ALIGN((unsigned long)(req + 1) +
 130                              crypto_aead_reqsize(aead),
 131                              __alignof__(struct scatterlist));
 132 }
 133
 134 static void esp_output_done(struct crypto_async_request *base, int err)
 135 {
 136         struct sk_buff *skb = base->data;
 137
 138         kfree(ESP_SKB_CB(skb)->tmp);
 139         xfrm_output_resume(skb, err);
 140 }
 141
 142 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 143 {
 144         int err;
 145         struct ip_esp_hdr *esph;
 146         struct crypto_aead *aead;
 147         struct aead_givcrypt_request *req;
 148         struct scatterlist *sg;
 149         struct scatterlist *asg;
 150         struct sk_buff *trailer;
 151         void *tmp;
 152         int blksize;
 153         int clen;
 154         int alen;
 155         int plen;
 156         int tfclen;
 157         int nfrags;
 158         int assoclen;
 159         int sglists;
 160         int seqhilen;
 161         u8 *iv;
 162         u8 *tail;
 163         __be32 *seqhi;
 164         struct esp_data *esp = x->data;
 165
 166         /* skb is pure payload to encrypt */
 167         err = -ENOMEM;
 168
 169         aead = esp->aead;
 170         alen = crypto_aead_authsize(aead);
 171
 172         tfclen = 0;
 173         if (x->tfcpad) {
 174                 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
 175                 u32 padto;
 176
 177                 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
 178                 if (skb->len < padto)
 179                         tfclen = padto - skb->len;
 180         }
 181         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 182         clen = ALIGN(skb->len + 2 + tfclen, blksize);
 183         if (esp->padlen)
 184                 clen = ALIGN(clen, esp->padlen);
 185         plen = clen - skb->len - tfclen;
 186
 187         err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
 188         if (err < 0)
 189                 goto error;
 190         nfrags = err;
 191
 192         assoclen = sizeof(*esph);
 193         sglists = 1;
 194         seqhilen = 0;
 195
 196         if (x->props.flags & XFRM_STATE_ESN) {
 197                 sglists += 2;
 198                 seqhilen += sizeof(__be32);
 199                 assoclen += seqhilen;
 200         }
 201
 202         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 203         if (!tmp)
 204                 goto error;
 205
 206         seqhi = esp_tmp_seqhi(tmp);
 207         iv = esp_tmp_iv(aead, tmp, seqhilen);
 208         req = esp_tmp_givreq(aead, iv);
 209         asg = esp_givreq_sg(aead, req);
 210         sg = asg + sglists;
 211
 212         /* Fill padding... */
 213         tail = skb_tail_pointer(trailer);
 214         if (tfclen) {
 215                 memset(tail, 0, tfclen);
 216                 tail += tfclen;
 217         }
 218         do {
 219                 int i;
 220                 for (i = 0; i < plen - 2; i++)
 221                         tail[i] = i + 1;
 222         } while (0);
 223         tail[plen - 2] = plen - 2;
 224         tail[plen - 1] = *skb_mac_header(skb);
 225         pskb_put(skb, trailer, clen - skb->len + alen);
 226
 227         skb_push(skb, -skb_network_offset(skb));
 228         esph = ip_esp_hdr(skb);
 229         *skb_mac_header(skb) = IPPROTO_ESP;
 230
 231         esph->spi = x->id.spi;
 232         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 233
 234         sg_init_table(sg, nfrags);
 235         skb_to_sgvec(skb, sg,
 236                      esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
 237                      clen + alen);
 238
 239         if ((x->props.flags & XFRM_STATE_ESN)) {
 240                 sg_init_table(asg, 3);
 241                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 242                 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
 243                 sg_set_buf(asg + 1, seqhi, seqhilen);
 244                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 245         } else
 246                 sg_init_one(asg, esph, sizeof(*esph));
 247
 248         aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
 249         aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
 250         aead_givcrypt_set_assoc(req, asg, assoclen);
 251         aead_givcrypt_set_giv(req, esph->enc_data,
 252                               XFRM_SKB_CB(skb)->seq.output.low);
 253
 254         ESP_SKB_CB(skb)->tmp = tmp;
 255         err = crypto_aead_givencrypt(req);
 256         if (err == -EINPROGRESS)
 257                 goto error;
 258
 259         if (err == -EBUSY)
 260                 err = NET_XMIT_DROP;
 261
 262         kfree(tmp);
 263
 264 error:
 265         return err;
 266 }
 267
 268 static int esp_input_done2(struct sk_buff *skb, int err)
 269 {
 270         struct xfrm_state *x = xfrm_input_state(skb);
 271         struct esp_data *esp = x->data;
 272         struct crypto_aead *aead = esp->aead;
 273         int alen = crypto_aead_authsize(aead);
 274         int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 275         int elen = skb->len - hlen;
 276         int hdr_len = skb_network_header_len(skb);
 277         int padlen;
 278         u8 nexthdr[2];
 279
 280         kfree(ESP_SKB_CB(skb)->tmp);
 281
 282         if (unlikely(err))
 283                 goto out;
 284
 285         if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
 286                 BUG();
 287
 288         err = -EINVAL;
 289         padlen = nexthdr[0];
 290         if (padlen + 2 + alen >= elen) {
 291                 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
 292                                "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
 293                 goto out;
 294         }
 295
 296         /* ... check padding bits here. Silly. :-) */
 297
 298         pskb_trim(skb, skb->len - alen - padlen - 2);
 299         __skb_pull(skb, hlen);
 300         skb_set_transport_header(skb, -hdr_len);
 301
 302         err = nexthdr[1];
 303
 304         /* RFC4303: Drop dummy packets without any error */
 305         if (err == IPPROTO_NONE)
 306                 err = -EINVAL;
 307
 308 out:
 309         return err;
 310 }
 311
 312 static void esp_input_done(struct crypto_async_request *base, int err)
 313 {
 314         struct sk_buff *skb = base->data;
 315
 316         xfrm_input_resume(skb, esp_input_done2(skb, err));
 317 }
 318
 319 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
 320 {
 321         struct ip_esp_hdr *esph;
 322         struct esp_data *esp = x->data;
 323         struct crypto_aead *aead = esp->aead;
 324         struct aead_request *req;
 325         struct sk_buff *trailer;
 326         int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
 327         int nfrags;
 328         int assoclen;
 329         int sglists;
 330         int seqhilen;
 331         int ret = 0;
 332         void *tmp;
 333         __be32 *seqhi;
 334         u8 *iv;
 335         struct scatterlist *sg;
 336         struct scatterlist *asg;
 337
 338         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
 339                 ret = -EINVAL;
 340                 goto out;
 341         }
 342
 343         if (elen <= 0) {
 344                 ret = -EINVAL;
 345                 goto out;
 346         }
 347
 348         if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
 349                 ret = -EINVAL;
 350                 goto out;
 351         }
 352
 353         ret = -ENOMEM;
 354
 355         assoclen = sizeof(*esph);
 356         sglists = 1;
 357         seqhilen = 0;
 358
 359         if (x->props.flags & XFRM_STATE_ESN) {
 360                 sglists += 2;
 361                 seqhilen += sizeof(__be32);
 362                 assoclen += seqhilen;
 363         }
 364
 365         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 366         if (!tmp)
 367                 goto out;
 368
 369         ESP_SKB_CB(skb)->tmp = tmp;
 370         seqhi = esp_tmp_seqhi(tmp);
 371         iv = esp_tmp_iv(aead, tmp, seqhilen);
 372         req = esp_tmp_req(aead, iv);
 373         asg = esp_req_sg(aead, req);
 374         sg = asg + sglists;
 375
 376         skb->ip_summed = CHECKSUM_NONE;
 377
 378         esph = (struct ip_esp_hdr *)skb->data;
 379
 380         /* Get ivec. This can be wrong, check against another impls. */
 381         iv = esph->enc_data;
 382
 383         sg_init_table(sg, nfrags);
 384         skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
 385
 386         if ((x->props.flags & XFRM_STATE_ESN)) {
 387                 sg_init_table(asg, 3);
 388                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 389                 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
 390                 sg_set_buf(asg + 1, seqhi, seqhilen);
 391                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 392         } else
 393                 sg_init_one(asg, esph, sizeof(*esph));
 394
 395         aead_request_set_callback(req, 0, esp_input_done, skb);
 396         aead_request_set_crypt(req, sg, sg, elen, iv);
 397         aead_request_set_assoc(req, asg, assoclen);
 398
 399         ret = crypto_aead_decrypt(req);
 400         if (ret == -EINPROGRESS)
 401                 goto out;
 402
 403         ret = esp_input_done2(skb, ret);
 404
 405 out:
 406         return ret;
 407 }
 408
 409 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
 410 {
 411         struct esp_data *esp = x->data;
 412         u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
 413         u32 align = max_t(u32, blksize, esp->padlen);
 414         u32 rem;
 415
 416         mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
 417         rem = mtu & (align - 1);
 418         mtu &= ~(align - 1);
 419
 420         if (x->props.mode != XFRM_MODE_TUNNEL) {
 421                 u32 padsize = ((blksize - 1) & 7) + 1;
 422                 mtu -= blksize - padsize;
 423                 mtu += min_t(u32, blksize - padsize, rem);
 424         }
 425
 426         return mtu - 2;
 427 }
 428
 429 static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 430                      u8 type, u8 code, int offset, __be32 info)
 431 {
 432         struct net *net = dev_net(skb->dev);
 433         const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
 434         struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
 435         struct xfrm_state *x;
 436
 437         if (type != ICMPV6_DEST_UNREACH &&
 438             type != ICMPV6_PKT_TOOBIG)
 439                 return;
 440
 441         x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
 442                               esph->spi, IPPROTO_ESP, AF_INET6);
 443         if (!x)
 444                 return;
 445         printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%pI6\n",
 446                         ntohl(esph->spi), &iph->daddr);
 447         xfrm_state_put(x);
 448 }
 449
 450 static void esp6_destroy(struct xfrm_state *x)
 451 {
 452         struct esp_data *esp = x->data;
 453
 454         if (!esp)
 455                 return;
 456
 457         crypto_free_aead(esp->aead);
 458         kfree(esp);
 459 }
 460
 461 static int esp_init_aead(struct xfrm_state *x)
 462 {
 463         struct esp_data *esp = x->data;
 464         struct crypto_aead *aead;
 465         int err;
 466
 467         aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
 468         err = PTR_ERR(aead);
 469         if (IS_ERR(aead))
 470                 goto error;
 471
 472         esp->aead = aead;
 473
 474         err = crypto_aead_setkey(aead, x->aead->alg_key,
 475                                  (x->aead->alg_key_len + 7) / 8);
 476         if (err)
 477                 goto error;
 478
 479         err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
 480         if (err)
 481                 goto error;
 482
 483 error:
 484         return err;
 485 }
 486
 487 static int esp_init_authenc(struct xfrm_state *x)
 488 {
 489         struct esp_data *esp = x->data;
 490         struct crypto_aead *aead;
 491         struct crypto_authenc_key_param *param;
 492         struct rtattr *rta;
 493         char *key;
 494         char *p;
 495         char authenc_name[CRYPTO_MAX_ALG_NAME];
 496         unsigned int keylen;
 497         int err;
 498
 499         err = -EINVAL;
 500         if (x->ealg == NULL)
 501                 goto error;
 502
 503         err = -ENAMETOOLONG;
 504
 505         if ((x->props.flags & XFRM_STATE_ESN)) {
 506                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 507                              "authencesn(%s,%s)",
 508                              x->aalg ? x->aalg->alg_name : "digest_null",
 509                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 510                         goto error;
 511         } else {
 512                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 513                              "authenc(%s,%s)",
 514                              x->aalg ? x->aalg->alg_name : "digest_null",
 515                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 516                         goto error;
 517         }
 518
 519         aead = crypto_alloc_aead(authenc_name, 0, 0);
 520         err = PTR_ERR(aead);
 521         if (IS_ERR(aead))
 522                 goto error;
 523
 524         esp->aead = aead;
 525
 526         keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
 527                  (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
 528         err = -ENOMEM;
 529         key = kmalloc(keylen, GFP_KERNEL);
 530         if (!key)
 531                 goto error;
 532
 533         p = key;
 534         rta = (void *)p;
 535         rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
 536         rta->rta_len = RTA_LENGTH(sizeof(*param));
 537         param = RTA_DATA(rta);
 538         p += RTA_SPACE(sizeof(*param));
 539
 540         if (x->aalg) {
 541                 struct xfrm_algo_desc *aalg_desc;
 542
 543                 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
 544                 p += (x->aalg->alg_key_len + 7) / 8;
 545
 546                 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
 547                 BUG_ON(!aalg_desc);
 548
 549                 err = -EINVAL;
 550                 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
 551                     crypto_aead_authsize(aead)) {
 552                         NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
 553                                  x->aalg->alg_name,
 554                                  crypto_aead_authsize(aead),
 555                                  aalg_desc->uinfo.auth.icv_fullbits/8);
 556                         goto free_key;
 557                 }
 558
 559                 err = crypto_aead_setauthsize(
 560                         aead, x->aalg->alg_trunc_len / 8);
 561                 if (err)
 562                         goto free_key;
 563         }
 564
 565         param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
 566         memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
 567
 568         err = crypto_aead_setkey(aead, key, keylen);
 569
 570 free_key:
 571         kfree(key);
 572
 573 error:
 574         return err;
 575 }
 576
 577 static int esp6_init_state(struct xfrm_state *x)
 578 {
 579         struct esp_data *esp;
 580         struct crypto_aead *aead;
 581         u32 align;
 582         int err;
 583
 584         if (x->encap)
 585                 return -EINVAL;
 586
 587         esp = kzalloc(sizeof(*esp), GFP_KERNEL);
 588         if (esp == NULL)
 589                 return -ENOMEM;
 590
 591         x->data = esp;
 592
 593         if (x->aead)
 594                 err = esp_init_aead(x);
 595         else
 596                 err = esp_init_authenc(x);
 597
 598         if (err)
 599                 goto error;
 600
 601         aead = esp->aead;
 602
 603         esp->padlen = 0;
 604
 605         x->props.header_len = sizeof(struct ip_esp_hdr) +
 606                               crypto_aead_ivsize(aead);
 607         switch (x->props.mode) {
 608         case XFRM_MODE_BEET:
 609                 if (x->sel.family != AF_INET6)
 610                         x->props.header_len += IPV4_BEET_PHMAXLEN +
 611                                                (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
 612                 break;
 613         case XFRM_MODE_TRANSPORT:
 614                 break;
 615         case XFRM_MODE_TUNNEL:
 616                 x->props.header_len += sizeof(struct ipv6hdr);
 617                 break;
 618         default:
 619                 goto error;
 620         }
 621
 622         align = ALIGN(crypto_aead_blocksize(aead), 4);
 623         if (esp->padlen)
 624                 align = max_t(u32, align, esp->padlen);
 625         x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
 626
 627 error:
 628         return err;
 629 }
 630
 631 static const struct xfrm_type esp6_type =
 632 {
 633         .description    = "ESP6",
 634         .owner          = THIS_MODULE,
 635         .proto          = IPPROTO_ESP,
 636         .flags          = XFRM_TYPE_REPLAY_PROT,
 637         .init_state     = esp6_init_state,
 638         .destructor     = esp6_destroy,
 639         .get_mtu        = esp6_get_mtu,
 640         .input          = esp6_input,
 641         .output         = esp6_output,
 642         .hdr_offset     = xfrm6_find_1stfragopt,
 643 };
 644
 645 static const struct inet6_protocol esp6_protocol = {
 646         .handler        =       xfrm6_rcv,
 647         .err_handler    =       esp6_err,
 648         .flags          =       INET6_PROTO_NOPOLICY,
 649 };
 650
 651 static int __init esp6_init(void)
 652 {
 653         if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
 654                 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
 655                 return -EAGAIN;
 656         }
 657         if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
 658                 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
 659                 xfrm_unregister_type(&esp6_type, AF_INET6);
 660                 return -EAGAIN;
 661         }
 662
 663         return 0;
 664 }
 665
 666 static void __exit esp6_fini(void)
 667 {
 668         if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
 669                 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
 670         if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
 671                 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
 672 }
 673
 674 module_init(esp6_init);
 675 module_exit(esp6_fini);
 676
 677 MODULE_LICENSE("GPL");
 678 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);