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 #define pr_fmt(fmt) "IPv6: " fmt
  28
  29 #include <crypto/aead.h>
  30 #include <crypto/authenc.h>
  31 #include <linux/err.h>
  32 #include <linux/module.h>
  33 #include <net/ip.h>
  34 #include <net/xfrm.h>
  35 #include <net/esp.h>
  36 #include <linux/scatterlist.h>
  37 #include <linux/kernel.h>
  38 #include <linux/pfkeyv2.h>
  39 #include <linux/random.h>
  40 #include <linux/slab.h>
  41 #include <linux/spinlock.h>
  42 #include <net/ip6_route.h>
  43 #include <net/icmp.h>
  44 #include <net/ipv6.h>
  45 #include <net/protocol.h>
  46 #include <linux/icmpv6.h>
  47
  48 struct esp_skb_cb {
  49         struct xfrm_skb_cb xfrm;
  50         void *tmp;
  51 };
  52
  53 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
  54
  55 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
  56
  57 /*
  58  * Allocate an AEAD request structure with extra space for SG and IV.
  59  *
  60  * For alignment considerations the upper 32 bits of the sequence number are
  61  * placed at the front, if present. Followed by the IV, the request and finally
  62  * the SG list.
  63  *
  64  * TODO: Use spare space in skb for this where possible.
  65  */
  66 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
  67 {
  68         unsigned int len;
  69
  70         len = seqihlen;
  71
  72         len += crypto_aead_ivsize(aead);
  73
  74         if (len) {
  75                 len += crypto_aead_alignmask(aead) &
  76                        ~(crypto_tfm_ctx_alignment() - 1);
  77                 len = ALIGN(len, crypto_tfm_ctx_alignment());
  78         }
  79
  80         len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
  81         len = ALIGN(len, __alignof__(struct scatterlist));
  82
  83         len += sizeof(struct scatterlist) * nfrags;
  84
  85         return kmalloc(len, GFP_ATOMIC);
  86 }
  87
  88 static inline __be32 *esp_tmp_seqhi(void *tmp)
  89 {
  90         return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
  91 }
  92
  93 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
  94 {
  95         return crypto_aead_ivsize(aead) ?
  96                PTR_ALIGN((u8 *)tmp + seqhilen,
  97                          crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
  98 }
  99
 100 static inline struct aead_givcrypt_request *esp_tmp_givreq(
 101         struct crypto_aead *aead, u8 *iv)
 102 {
 103         struct aead_givcrypt_request *req;
 104
 105         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
 106                                 crypto_tfm_ctx_alignment());
 107         aead_givcrypt_set_tfm(req, aead);
 108         return req;
 109 }
 110
 111 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
 112 {
 113         struct aead_request *req;
 114
 115         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
 116                                 crypto_tfm_ctx_alignment());
 117         aead_request_set_tfm(req, aead);
 118         return req;
 119 }
 120
 121 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
 122                                              struct aead_request *req)
 123 {
 124         return (void *)ALIGN((unsigned long)(req + 1) +
 125                              crypto_aead_reqsize(aead),
 126                              __alignof__(struct scatterlist));
 127 }
 128
 129 static inline struct scatterlist *esp_givreq_sg(
 130         struct crypto_aead *aead, struct aead_givcrypt_request *req)
 131 {
 132         return (void *)ALIGN((unsigned long)(req + 1) +
 133                              crypto_aead_reqsize(aead),
 134                              __alignof__(struct scatterlist));
 135 }
 136
 137 static void esp_output_done(struct crypto_async_request *base, int err)
 138 {
 139         struct sk_buff *skb = base->data;
 140
 141         kfree(ESP_SKB_CB(skb)->tmp);
 142         xfrm_output_resume(skb, err);
 143 }
 144
 145 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 146 {
 147         int err;
 148         struct ip_esp_hdr *esph;
 149         struct crypto_aead *aead;
 150         struct aead_givcrypt_request *req;
 151         struct scatterlist *sg;
 152         struct scatterlist *asg;
 153         struct sk_buff *trailer;
 154         void *tmp;
 155         int blksize;
 156         int clen;
 157         int alen;
 158         int plen;
 159         int tfclen;
 160         int nfrags;
 161         int assoclen;
 162         int sglists;
 163         int seqhilen;
 164         u8 *iv;
 165         u8 *tail;
 166         __be32 *seqhi;
 167         struct esp_data *esp = x->data;
 168
 169         /* skb is pure payload to encrypt */
 170         aead = esp->aead;
 171         alen = crypto_aead_authsize(aead);
 172
 173         tfclen = 0;
 174         if (x->tfcpad) {
 175                 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
 176                 u32 padto;
 177
 178                 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
 179                 if (skb->len < padto)
 180                         tfclen = padto - skb->len;
 181         }
 182         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 183         clen = ALIGN(skb->len + 2 + tfclen, blksize);
 184         if (esp->padlen)
 185                 clen = ALIGN(clen, esp->padlen);
 186         plen = clen - skb->len - tfclen;
 187
 188         err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
 189         if (err < 0)
 190                 goto error;
 191         nfrags = err;
 192
 193         assoclen = sizeof(*esph);
 194         sglists = 1;
 195         seqhilen = 0;
 196
 197         if (x->props.flags & XFRM_STATE_ESN) {
 198                 sglists += 2;
 199                 seqhilen += sizeof(__be32);
 200                 assoclen += seqhilen;
 201         }
 202
 203         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 204         if (!tmp) {
 205                 err = -ENOMEM;
 206                 goto error;
 207         }
 208
 209         seqhi = esp_tmp_seqhi(tmp);
 210         iv = esp_tmp_iv(aead, tmp, seqhilen);
 211         req = esp_tmp_givreq(aead, iv);
 212         asg = esp_givreq_sg(aead, req);
 213         sg = asg + sglists;
 214
 215         /* Fill padding... */
 216         tail = skb_tail_pointer(trailer);
 217         if (tfclen) {
 218                 memset(tail, 0, tfclen);
 219                 tail += tfclen;
 220         }
 221         do {
 222                 int i;
 223                 for (i = 0; i < plen - 2; i++)
 224                         tail[i] = i + 1;
 225         } while (0);
 226         tail[plen - 2] = plen - 2;
 227         tail[plen - 1] = *skb_mac_header(skb);
 228         pskb_put(skb, trailer, clen - skb->len + alen);
 229
 230         skb_push(skb, -skb_network_offset(skb));
 231         esph = ip_esp_hdr(skb);
 232         *skb_mac_header(skb) = IPPROTO_ESP;
 233
 234         esph->spi = x->id.spi;
 235         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 236
 237         sg_init_table(sg, nfrags);
 238         skb_to_sgvec(skb, sg,
 239                      esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
 240                      clen + alen);
 241
 242         if ((x->props.flags & XFRM_STATE_ESN)) {
 243                 sg_init_table(asg, 3);
 244                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 245                 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
 246                 sg_set_buf(asg + 1, seqhi, seqhilen);
 247                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 248         } else
 249                 sg_init_one(asg, esph, sizeof(*esph));
 250
 251         aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
 252         aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
 253         aead_givcrypt_set_assoc(req, asg, assoclen);
 254         aead_givcrypt_set_giv(req, esph->enc_data,
 255                               XFRM_SKB_CB(skb)->seq.output.low);
 256
 257         ESP_SKB_CB(skb)->tmp = tmp;
 258         err = crypto_aead_givencrypt(req);
 259         if (err == -EINPROGRESS)
 260                 goto error;
 261
 262         if (err == -EBUSY)
 263                 err = NET_XMIT_DROP;
 264
 265         kfree(tmp);
 266
 267 error:
 268         return err;
 269 }
 270
 271 static int esp_input_done2(struct sk_buff *skb, int err)
 272 {
 273         struct xfrm_state *x = xfrm_input_state(skb);
 274         struct esp_data *esp = x->data;
 275         struct crypto_aead *aead = esp->aead;
 276         int alen = crypto_aead_authsize(aead);
 277         int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 278         int elen = skb->len - hlen;
 279         int hdr_len = skb_network_header_len(skb);
 280         int padlen;
 281         u8 nexthdr[2];
 282
 283         kfree(ESP_SKB_CB(skb)->tmp);
 284
 285         if (unlikely(err))
 286                 goto out;
 287
 288         if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
 289                 BUG();
 290
 291         err = -EINVAL;
 292         padlen = nexthdr[0];
 293         if (padlen + 2 + alen >= elen) {
 294                 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
 295                                "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
 296                 goto out;
 297         }
 298
 299         /* ... check padding bits here. Silly. :-) */
 300
 301         pskb_trim(skb, skb->len - alen - padlen - 2);
 302         __skb_pull(skb, hlen);
 303         skb_set_transport_header(skb, -hdr_len);
 304
 305         err = nexthdr[1];
 306
 307         /* RFC4303: Drop dummy packets without any error */
 308         if (err == IPPROTO_NONE)
 309                 err = -EINVAL;
 310
 311 out:
 312         return err;
 313 }
 314
 315 static void esp_input_done(struct crypto_async_request *base, int err)
 316 {
 317         struct sk_buff *skb = base->data;
 318
 319         xfrm_input_resume(skb, esp_input_done2(skb, err));
 320 }
 321
 322 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
 323 {
 324         struct ip_esp_hdr *esph;
 325         struct esp_data *esp = x->data;
 326         struct crypto_aead *aead = esp->aead;
 327         struct aead_request *req;
 328         struct sk_buff *trailer;
 329         int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
 330         int nfrags;
 331         int assoclen;
 332         int sglists;
 333         int seqhilen;
 334         int ret = 0;
 335         void *tmp;
 336         __be32 *seqhi;
 337         u8 *iv;
 338         struct scatterlist *sg;
 339         struct scatterlist *asg;
 340
 341         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
 342                 ret = -EINVAL;
 343                 goto out;
 344         }
 345
 346         if (elen <= 0) {
 347                 ret = -EINVAL;
 348                 goto out;
 349         }
 350
 351         if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
 352                 ret = -EINVAL;
 353                 goto out;
 354         }
 355
 356         ret = -ENOMEM;
 357
 358         assoclen = sizeof(*esph);
 359         sglists = 1;
 360         seqhilen = 0;
 361
 362         if (x->props.flags & XFRM_STATE_ESN) {
 363                 sglists += 2;
 364                 seqhilen += sizeof(__be32);
 365                 assoclen += seqhilen;
 366         }
 367
 368         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 369         if (!tmp)
 370                 goto out;
 371
 372         ESP_SKB_CB(skb)->tmp = tmp;
 373         seqhi = esp_tmp_seqhi(tmp);
 374         iv = esp_tmp_iv(aead, tmp, seqhilen);
 375         req = esp_tmp_req(aead, iv);
 376         asg = esp_req_sg(aead, req);
 377         sg = asg + sglists;
 378
 379         skb->ip_summed = CHECKSUM_NONE;
 380
 381         esph = (struct ip_esp_hdr *)skb->data;
 382
 383         /* Get ivec. This can be wrong, check against another impls. */
 384         iv = esph->enc_data;
 385
 386         sg_init_table(sg, nfrags);
 387         skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
 388
 389         if ((x->props.flags & XFRM_STATE_ESN)) {
 390                 sg_init_table(asg, 3);
 391                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 392                 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
 393                 sg_set_buf(asg + 1, seqhi, seqhilen);
 394                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 395         } else
 396                 sg_init_one(asg, esph, sizeof(*esph));
 397
 398         aead_request_set_callback(req, 0, esp_input_done, skb);
 399         aead_request_set_crypt(req, sg, sg, elen, iv);
 400         aead_request_set_assoc(req, asg, assoclen);
 401
 402         ret = crypto_aead_decrypt(req);
 403         if (ret == -EINPROGRESS)
 404                 goto out;
 405
 406         ret = esp_input_done2(skb, ret);
 407
 408 out:
 409         return ret;
 410 }
 411
 412 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
 413 {
 414         struct esp_data *esp = x->data;
 415         u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
 416         u32 align = max_t(u32, blksize, esp->padlen);
 417         unsigned int net_adj;
 418
 419         if (x->props.mode != XFRM_MODE_TUNNEL)
 420                 net_adj = sizeof(struct ipv6hdr);
 421         else
 422                 net_adj = 0;
 423
 424         return ((mtu - x->props.header_len - crypto_aead_authsize(esp->aead) -
 425                  net_adj) & ~(align - 1)) + (net_adj - 2);
 426 }
 427
 428 static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 429                      u8 type, u8 code, int offset, __be32 info)
 430 {
 431         struct net *net = dev_net(skb->dev);
 432         const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
 433         struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
 434         struct xfrm_state *x;
 435
 436         if (type != ICMPV6_DEST_UNREACH &&
 437             type != ICMPV6_PKT_TOOBIG &&
 438             type != NDISC_REDIRECT)
 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
 446         if (type == NDISC_REDIRECT)
 447                 ip6_redirect(skb, net, 0, 0);
 448         else
 449                 ip6_update_pmtu(skb, net, info, 0, 0);
 450         xfrm_state_put(x);
 451 }
 452
 453 static void esp6_destroy(struct xfrm_state *x)
 454 {
 455         struct esp_data *esp = x->data;
 456
 457         if (!esp)
 458                 return;
 459
 460         crypto_free_aead(esp->aead);
 461         kfree(esp);
 462 }
 463
 464 static int esp_init_aead(struct xfrm_state *x)
 465 {
 466         struct esp_data *esp = x->data;
 467         struct crypto_aead *aead;
 468         int err;
 469
 470         aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
 471         err = PTR_ERR(aead);
 472         if (IS_ERR(aead))
 473                 goto error;
 474
 475         esp->aead = aead;
 476
 477         err = crypto_aead_setkey(aead, x->aead->alg_key,
 478                                  (x->aead->alg_key_len + 7) / 8);
 479         if (err)
 480                 goto error;
 481
 482         err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
 483         if (err)
 484                 goto error;
 485
 486 error:
 487         return err;
 488 }
 489
 490 static int esp_init_authenc(struct xfrm_state *x)
 491 {
 492         struct esp_data *esp = x->data;
 493         struct crypto_aead *aead;
 494         struct crypto_authenc_key_param *param;
 495         struct rtattr *rta;
 496         char *key;
 497         char *p;
 498         char authenc_name[CRYPTO_MAX_ALG_NAME];
 499         unsigned int keylen;
 500         int err;
 501
 502         err = -EINVAL;
 503         if (x->ealg == NULL)
 504                 goto error;
 505
 506         err = -ENAMETOOLONG;
 507
 508         if ((x->props.flags & XFRM_STATE_ESN)) {
 509                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 510                              "authencesn(%s,%s)",
 511                              x->aalg ? x->aalg->alg_name : "digest_null",
 512                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 513                         goto error;
 514         } else {
 515                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 516                              "authenc(%s,%s)",
 517                              x->aalg ? x->aalg->alg_name : "digest_null",
 518                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 519                         goto error;
 520         }
 521
 522         aead = crypto_alloc_aead(authenc_name, 0, 0);
 523         err = PTR_ERR(aead);
 524         if (IS_ERR(aead))
 525                 goto error;
 526
 527         esp->aead = aead;
 528
 529         keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
 530                  (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
 531         err = -ENOMEM;
 532         key = kmalloc(keylen, GFP_KERNEL);
 533         if (!key)
 534                 goto error;
 535
 536         p = key;
 537         rta = (void *)p;
 538         rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
 539         rta->rta_len = RTA_LENGTH(sizeof(*param));
 540         param = RTA_DATA(rta);
 541         p += RTA_SPACE(sizeof(*param));
 542
 543         if (x->aalg) {
 544                 struct xfrm_algo_desc *aalg_desc;
 545
 546                 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
 547                 p += (x->aalg->alg_key_len + 7) / 8;
 548
 549                 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
 550                 BUG_ON(!aalg_desc);
 551
 552                 err = -EINVAL;
 553                 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
 554                     crypto_aead_authsize(aead)) {
 555                         NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
 556                                  x->aalg->alg_name,
 557                                  crypto_aead_authsize(aead),
 558                                  aalg_desc->uinfo.auth.icv_fullbits/8);
 559                         goto free_key;
 560                 }
 561
 562                 err = crypto_aead_setauthsize(
 563                         aead, x->aalg->alg_trunc_len / 8);
 564                 if (err)
 565                         goto free_key;
 566         }
 567
 568         param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
 569         memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
 570
 571         err = crypto_aead_setkey(aead, key, keylen);
 572
 573 free_key:
 574         kfree(key);
 575
 576 error:
 577         return err;
 578 }
 579
 580 static int esp6_init_state(struct xfrm_state *x)
 581 {
 582         struct esp_data *esp;
 583         struct crypto_aead *aead;
 584         u32 align;
 585         int err;
 586
 587         if (x->encap)
 588                 return -EINVAL;
 589
 590         esp = kzalloc(sizeof(*esp), GFP_KERNEL);
 591         if (esp == NULL)
 592                 return -ENOMEM;
 593
 594         x->data = esp;
 595
 596         if (x->aead)
 597                 err = esp_init_aead(x);
 598         else
 599                 err = esp_init_authenc(x);
 600
 601         if (err)
 602                 goto error;
 603
 604         aead = esp->aead;
 605
 606         esp->padlen = 0;
 607
 608         x->props.header_len = sizeof(struct ip_esp_hdr) +
 609                               crypto_aead_ivsize(aead);
 610         switch (x->props.mode) {
 611         case XFRM_MODE_BEET:
 612                 if (x->sel.family != AF_INET6)
 613                         x->props.header_len += IPV4_BEET_PHMAXLEN +
 614                                                (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
 615                 break;
 616         case XFRM_MODE_TRANSPORT:
 617                 break;
 618         case XFRM_MODE_TUNNEL:
 619                 x->props.header_len += sizeof(struct ipv6hdr);
 620                 break;
 621         default:
 622                 goto error;
 623         }
 624
 625         align = ALIGN(crypto_aead_blocksize(aead), 4);
 626         if (esp->padlen)
 627                 align = max_t(u32, align, esp->padlen);
 628         x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
 629
 630 error:
 631         return err;
 632 }
 633
 634 static const struct xfrm_type esp6_type =
 635 {
 636         .description    = "ESP6",
 637         .owner          = THIS_MODULE,
 638         .proto          = IPPROTO_ESP,
 639         .flags          = XFRM_TYPE_REPLAY_PROT,
 640         .init_state     = esp6_init_state,
 641         .destructor     = esp6_destroy,
 642         .get_mtu        = esp6_get_mtu,
 643         .input          = esp6_input,
 644         .output         = esp6_output,
 645         .hdr_offset     = xfrm6_find_1stfragopt,
 646 };
 647
 648 static const struct inet6_protocol esp6_protocol = {
 649         .handler        =       xfrm6_rcv,
 650         .err_handler    =       esp6_err,
 651         .flags          =       INET6_PROTO_NOPOLICY,
 652 };
 653
 654 static int __init esp6_init(void)
 655 {
 656         if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
 657                 pr_info("%s: can't add xfrm type\n", __func__);
 658                 return -EAGAIN;
 659         }
 660         if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
 661                 pr_info("%s: can't add protocol\n", __func__);
 662                 xfrm_unregister_type(&esp6_type, AF_INET6);
 663                 return -EAGAIN;
 664         }
 665
 666         return 0;
 667 }
 668
 669 static void __exit esp6_fini(void)
 670 {
 671         if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
 672                 pr_info("%s: can't remove protocol\n", __func__);
 673         if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
 674                 pr_info("%s: can't remove xfrm type\n", __func__);
 675 }
 676
 677 module_init(esp6_init);
 678 module_exit(esp6_fini);
 679
 680 MODULE_LICENSE("GPL");
 681 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);