git.oblomov.eu Git - linux-2.6/blob - net/xfrm/xfrm_algo.c

   1 /*
   2  * xfrm algorithm interface
   3  *
   4  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/pfkeyv2.h>
  15 #include <linux/crypto.h>
  16 #include <linux/scatterlist.h>
  17 #include <net/xfrm.h>
  18 #if defined(CONFIG_INET_AH) || defined(CONFIG_INET_AH_MODULE) || defined(CONFIG_INET6_AH) || defined(CONFIG_INET6_AH_MODULE)
  19 #include <net/ah.h>
  20 #endif
  21 #if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)
  22 #include <net/esp.h>
  23 #endif
  24
  25 /*
  26  * Algorithms supported by IPsec.  These entries contain properties which
  27  * are used in key negotiation and xfrm processing, and are used to verify
  28  * that instantiated crypto transforms have correct parameters for IPsec
  29  * purposes.
  30  */
  31 static struct xfrm_algo_desc aead_list[] = {
  32 {
  33         .name = "rfc4106(gcm(aes))",
  34
  35         .uinfo = {
  36                 .aead = {
  37                         .icv_truncbits = 64,
  38                 }
  39         },
  40
  41         .desc = {
  42                 .sadb_alg_id = SADB_X_EALG_AES_GCM_ICV8,
  43                 .sadb_alg_ivlen = 8,
  44                 .sadb_alg_minbits = 128,
  45                 .sadb_alg_maxbits = 256
  46         }
  47 },
  48 {
  49         .name = "rfc4106(gcm(aes))",
  50
  51         .uinfo = {
  52                 .aead = {
  53                         .icv_truncbits = 96,
  54                 }
  55         },
  56
  57         .desc = {
  58                 .sadb_alg_id = SADB_X_EALG_AES_GCM_ICV12,
  59                 .sadb_alg_ivlen = 8,
  60                 .sadb_alg_minbits = 128,
  61                 .sadb_alg_maxbits = 256
  62         }
  63 },
  64 {
  65         .name = "rfc4106(gcm(aes))",
  66
  67         .uinfo = {
  68                 .aead = {
  69                         .icv_truncbits = 128,
  70                 }
  71         },
  72
  73         .desc = {
  74                 .sadb_alg_id = SADB_X_EALG_AES_GCM_ICV16,
  75                 .sadb_alg_ivlen = 8,
  76                 .sadb_alg_minbits = 128,
  77                 .sadb_alg_maxbits = 256
  78         }
  79 },
  80 {
  81         .name = "rfc4309(ccm(aes))",
  82
  83         .uinfo = {
  84                 .aead = {
  85                         .icv_truncbits = 64,
  86                 }
  87         },
  88
  89         .desc = {
  90                 .sadb_alg_id = SADB_X_EALG_AES_CCM_ICV8,
  91                 .sadb_alg_ivlen = 8,
  92                 .sadb_alg_minbits = 128,
  93                 .sadb_alg_maxbits = 256
  94         }
  95 },
  96 {
  97         .name = "rfc4309(ccm(aes))",
  98
  99         .uinfo = {
 100                 .aead = {
 101                         .icv_truncbits = 96,
 102                 }
 103         },
 104
 105         .desc = {
 106                 .sadb_alg_id = SADB_X_EALG_AES_CCM_ICV12,
 107                 .sadb_alg_ivlen = 8,
 108                 .sadb_alg_minbits = 128,
 109                 .sadb_alg_maxbits = 256
 110         }
 111 },
 112 {
 113         .name = "rfc4309(ccm(aes))",
 114
 115         .uinfo = {
 116                 .aead = {
 117                         .icv_truncbits = 128,
 118                 }
 119         },
 120
 121         .desc = {
 122                 .sadb_alg_id = SADB_X_EALG_AES_CCM_ICV16,
 123                 .sadb_alg_ivlen = 8,
 124                 .sadb_alg_minbits = 128,
 125                 .sadb_alg_maxbits = 256
 126         }
 127 },
 128 };
 129
 130 static struct xfrm_algo_desc aalg_list[] = {
 131 {
 132         .name = "hmac(digest_null)",
 133         .compat = "digest_null",
 134
 135         .uinfo = {
 136                 .auth = {
 137                         .icv_truncbits = 0,
 138                         .icv_fullbits = 0,
 139                 }
 140         },
 141
 142         .desc = {
 143                 .sadb_alg_id = SADB_X_AALG_NULL,
 144                 .sadb_alg_ivlen = 0,
 145                 .sadb_alg_minbits = 0,
 146                 .sadb_alg_maxbits = 0
 147         }
 148 },
 149 {
 150         .name = "hmac(md5)",
 151         .compat = "md5",
 152
 153         .uinfo = {
 154                 .auth = {
 155                         .icv_truncbits = 96,
 156                         .icv_fullbits = 128,
 157                 }
 158         },
 159
 160         .desc = {
 161                 .sadb_alg_id = SADB_AALG_MD5HMAC,
 162                 .sadb_alg_ivlen = 0,
 163                 .sadb_alg_minbits = 128,
 164                 .sadb_alg_maxbits = 128
 165         }
 166 },
 167 {
 168         .name = "hmac(sha1)",
 169         .compat = "sha1",
 170
 171         .uinfo = {
 172                 .auth = {
 173                         .icv_truncbits = 96,
 174                         .icv_fullbits = 160,
 175                 }
 176         },
 177
 178         .desc = {
 179                 .sadb_alg_id = SADB_AALG_SHA1HMAC,
 180                 .sadb_alg_ivlen = 0,
 181                 .sadb_alg_minbits = 160,
 182                 .sadb_alg_maxbits = 160
 183         }
 184 },
 185 {
 186         .name = "hmac(sha256)",
 187         .compat = "sha256",
 188
 189         .uinfo = {
 190                 .auth = {
 191                         .icv_truncbits = 96,
 192                         .icv_fullbits = 256,
 193                 }
 194         },
 195
 196         .desc = {
 197                 .sadb_alg_id = SADB_X_AALG_SHA2_256HMAC,
 198                 .sadb_alg_ivlen = 0,
 199                 .sadb_alg_minbits = 256,
 200                 .sadb_alg_maxbits = 256
 201         }
 202 },
 203 {
 204         .name = "hmac(ripemd160)",
 205         .compat = "ripemd160",
 206
 207         .uinfo = {
 208                 .auth = {
 209                         .icv_truncbits = 96,
 210                         .icv_fullbits = 160,
 211                 }
 212         },
 213
 214         .desc = {
 215                 .sadb_alg_id = SADB_X_AALG_RIPEMD160HMAC,
 216                 .sadb_alg_ivlen = 0,
 217                 .sadb_alg_minbits = 160,
 218                 .sadb_alg_maxbits = 160
 219         }
 220 },
 221 {
 222         .name = "xcbc(aes)",
 223
 224         .uinfo = {
 225                 .auth = {
 226                         .icv_truncbits = 96,
 227                         .icv_fullbits = 128,
 228                 }
 229         },
 230
 231         .desc = {
 232                 .sadb_alg_id = SADB_X_AALG_AES_XCBC_MAC,
 233                 .sadb_alg_ivlen = 0,
 234                 .sadb_alg_minbits = 128,
 235                 .sadb_alg_maxbits = 128
 236         }
 237 },
 238 };
 239
 240 static struct xfrm_algo_desc ealg_list[] = {
 241 {
 242         .name = "ecb(cipher_null)",
 243         .compat = "cipher_null",
 244
 245         .uinfo = {
 246                 .encr = {
 247                         .blockbits = 8,
 248                         .defkeybits = 0,
 249                 }
 250         },
 251
 252         .desc = {
 253                 .sadb_alg_id =  SADB_EALG_NULL,
 254                 .sadb_alg_ivlen = 0,
 255                 .sadb_alg_minbits = 0,
 256                 .sadb_alg_maxbits = 0
 257         }
 258 },
 259 {
 260         .name = "cbc(des)",
 261         .compat = "des",
 262
 263         .uinfo = {
 264                 .encr = {
 265                         .blockbits = 64,
 266                         .defkeybits = 64,
 267                 }
 268         },
 269
 270         .desc = {
 271                 .sadb_alg_id = SADB_EALG_DESCBC,
 272                 .sadb_alg_ivlen = 8,
 273                 .sadb_alg_minbits = 64,
 274                 .sadb_alg_maxbits = 64
 275         }
 276 },
 277 {
 278         .name = "cbc(des3_ede)",
 279         .compat = "des3_ede",
 280
 281         .uinfo = {
 282                 .encr = {
 283                         .blockbits = 64,
 284                         .defkeybits = 192,
 285                 }
 286         },
 287
 288         .desc = {
 289                 .sadb_alg_id = SADB_EALG_3DESCBC,
 290                 .sadb_alg_ivlen = 8,
 291                 .sadb_alg_minbits = 192,
 292                 .sadb_alg_maxbits = 192
 293         }
 294 },
 295 {
 296         .name = "cbc(cast128)",
 297         .compat = "cast128",
 298
 299         .uinfo = {
 300                 .encr = {
 301                         .blockbits = 64,
 302                         .defkeybits = 128,
 303                 }
 304         },
 305
 306         .desc = {
 307                 .sadb_alg_id = SADB_X_EALG_CASTCBC,
 308                 .sadb_alg_ivlen = 8,
 309                 .sadb_alg_minbits = 40,
 310                 .sadb_alg_maxbits = 128
 311         }
 312 },
 313 {
 314         .name = "cbc(blowfish)",
 315         .compat = "blowfish",
 316
 317         .uinfo = {
 318                 .encr = {
 319                         .blockbits = 64,
 320                         .defkeybits = 128,
 321                 }
 322         },
 323
 324         .desc = {
 325                 .sadb_alg_id = SADB_X_EALG_BLOWFISHCBC,
 326                 .sadb_alg_ivlen = 8,
 327                 .sadb_alg_minbits = 40,
 328                 .sadb_alg_maxbits = 448
 329         }
 330 },
 331 {
 332         .name = "cbc(aes)",
 333         .compat = "aes",
 334
 335         .uinfo = {
 336                 .encr = {
 337                         .blockbits = 128,
 338                         .defkeybits = 128,
 339                 }
 340         },
 341
 342         .desc = {
 343                 .sadb_alg_id = SADB_X_EALG_AESCBC,
 344                 .sadb_alg_ivlen = 8,
 345                 .sadb_alg_minbits = 128,
 346                 .sadb_alg_maxbits = 256
 347         }
 348 },
 349 {
 350         .name = "cbc(serpent)",
 351         .compat = "serpent",
 352
 353         .uinfo = {
 354                 .encr = {
 355                         .blockbits = 128,
 356                         .defkeybits = 128,
 357                 }
 358         },
 359
 360         .desc = {
 361                 .sadb_alg_id = SADB_X_EALG_SERPENTCBC,
 362                 .sadb_alg_ivlen = 8,
 363                 .sadb_alg_minbits = 128,
 364                 .sadb_alg_maxbits = 256,
 365         }
 366 },
 367 {
 368         .name = "cbc(camellia)",
 369
 370         .uinfo = {
 371                 .encr = {
 372                         .blockbits = 128,
 373                         .defkeybits = 128,
 374                 }
 375         },
 376
 377         .desc = {
 378                 .sadb_alg_id = SADB_X_EALG_CAMELLIACBC,
 379                 .sadb_alg_ivlen = 8,
 380                 .sadb_alg_minbits = 128,
 381                 .sadb_alg_maxbits = 256
 382         }
 383 },
 384 {
 385         .name = "cbc(twofish)",
 386         .compat = "twofish",
 387
 388         .uinfo = {
 389                 .encr = {
 390                         .blockbits = 128,
 391                         .defkeybits = 128,
 392                 }
 393         },
 394
 395         .desc = {
 396                 .sadb_alg_id = SADB_X_EALG_TWOFISHCBC,
 397                 .sadb_alg_ivlen = 8,
 398                 .sadb_alg_minbits = 128,
 399                 .sadb_alg_maxbits = 256
 400         }
 401 },
 402 {
 403         .name = "rfc3686(ctr(aes))",
 404
 405         .uinfo = {
 406                 .encr = {
 407                         .blockbits = 128,
 408                         .defkeybits = 160, /* 128-bit key + 32-bit nonce */
 409                 }
 410         },
 411
 412         .desc = {
 413                 .sadb_alg_id = SADB_X_EALG_AESCTR,
 414                 .sadb_alg_ivlen = 8,
 415                 .sadb_alg_minbits = 128,
 416                 .sadb_alg_maxbits = 256
 417         }
 418 },
 419 };
 420
 421 static struct xfrm_algo_desc calg_list[] = {
 422 {
 423         .name = "deflate",
 424         .uinfo = {
 425                 .comp = {
 426                         .threshold = 90,
 427                 }
 428         },
 429         .desc = { .sadb_alg_id = SADB_X_CALG_DEFLATE }
 430 },
 431 {
 432         .name = "lzs",
 433         .uinfo = {
 434                 .comp = {
 435                         .threshold = 90,
 436                 }
 437         },
 438         .desc = { .sadb_alg_id = SADB_X_CALG_LZS }
 439 },
 440 {
 441         .name = "lzjh",
 442         .uinfo = {
 443                 .comp = {
 444                         .threshold = 50,
 445                 }
 446         },
 447         .desc = { .sadb_alg_id = SADB_X_CALG_LZJH }
 448 },
 449 };
 450
 451 static inline int aead_entries(void)
 452 {
 453         return ARRAY_SIZE(aead_list);
 454 }
 455
 456 static inline int aalg_entries(void)
 457 {
 458         return ARRAY_SIZE(aalg_list);
 459 }
 460
 461 static inline int ealg_entries(void)
 462 {
 463         return ARRAY_SIZE(ealg_list);
 464 }
 465
 466 static inline int calg_entries(void)
 467 {
 468         return ARRAY_SIZE(calg_list);
 469 }
 470
 471 struct xfrm_algo_list {
 472         struct xfrm_algo_desc *algs;
 473         int entries;
 474         u32 type;
 475         u32 mask;
 476 };
 477
 478 static const struct xfrm_algo_list xfrm_aead_list = {
 479         .algs = aead_list,
 480         .entries = ARRAY_SIZE(aead_list),
 481         .type = CRYPTO_ALG_TYPE_AEAD,
 482         .mask = CRYPTO_ALG_TYPE_MASK,
 483 };
 484
 485 static const struct xfrm_algo_list xfrm_aalg_list = {
 486         .algs = aalg_list,
 487         .entries = ARRAY_SIZE(aalg_list),
 488         .type = CRYPTO_ALG_TYPE_HASH,
 489         .mask = CRYPTO_ALG_TYPE_HASH_MASK,
 490 };
 491
 492 static const struct xfrm_algo_list xfrm_ealg_list = {
 493         .algs = ealg_list,
 494         .entries = ARRAY_SIZE(ealg_list),
 495         .type = CRYPTO_ALG_TYPE_BLKCIPHER,
 496         .mask = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,
 497 };
 498
 499 static const struct xfrm_algo_list xfrm_calg_list = {
 500         .algs = calg_list,
 501         .entries = ARRAY_SIZE(calg_list),
 502         .type = CRYPTO_ALG_TYPE_COMPRESS,
 503         .mask = CRYPTO_ALG_TYPE_MASK,
 504 };
 505
 506 static struct xfrm_algo_desc *xfrm_find_algo(
 507         const struct xfrm_algo_list *algo_list,
 508         int match(const struct xfrm_algo_desc *entry, const void *data),
 509         const void *data, int probe)
 510 {
 511         struct xfrm_algo_desc *list = algo_list->algs;
 512         int i, status;
 513
 514         for (i = 0; i < algo_list->entries; i++) {
 515                 if (!match(list + i, data))
 516                         continue;
 517
 518                 if (list[i].available)
 519                         return &list[i];
 520
 521                 if (!probe)
 522                         break;
 523
 524                 status = crypto_has_alg(list[i].name, algo_list->type,
 525                                         algo_list->mask);
 526                 if (!status)
 527                         break;
 528
 529                 list[i].available = status;
 530                 return &list[i];
 531         }
 532         return NULL;
 533 }
 534
 535 static int xfrm_alg_id_match(const struct xfrm_algo_desc *entry,
 536                              const void *data)
 537 {
 538         return entry->desc.sadb_alg_id == (unsigned long)data;
 539 }
 540
 541 struct xfrm_algo_desc *xfrm_aalg_get_byid(int alg_id)
 542 {
 543         return xfrm_find_algo(&xfrm_aalg_list, xfrm_alg_id_match,
 544                               (void *)(unsigned long)alg_id, 1);
 545 }
 546 EXPORT_SYMBOL_GPL(xfrm_aalg_get_byid);
 547
 548 struct xfrm_algo_desc *xfrm_ealg_get_byid(int alg_id)
 549 {
 550         return xfrm_find_algo(&xfrm_ealg_list, xfrm_alg_id_match,
 551                               (void *)(unsigned long)alg_id, 1);
 552 }
 553 EXPORT_SYMBOL_GPL(xfrm_ealg_get_byid);
 554
 555 struct xfrm_algo_desc *xfrm_calg_get_byid(int alg_id)
 556 {
 557         return xfrm_find_algo(&xfrm_calg_list, xfrm_alg_id_match,
 558                               (void *)(unsigned long)alg_id, 1);
 559 }
 560 EXPORT_SYMBOL_GPL(xfrm_calg_get_byid);
 561
 562 static int xfrm_alg_name_match(const struct xfrm_algo_desc *entry,
 563                                const void *data)
 564 {
 565         const char *name = data;
 566
 567         return name && (!strcmp(name, entry->name) ||
 568                         (entry->compat && !strcmp(name, entry->compat)));
 569 }
 570
 571 struct xfrm_algo_desc *xfrm_aalg_get_byname(char *name, int probe)
 572 {
 573         return xfrm_find_algo(&xfrm_aalg_list, xfrm_alg_name_match, name,
 574                               probe);
 575 }
 576 EXPORT_SYMBOL_GPL(xfrm_aalg_get_byname);
 577
 578 struct xfrm_algo_desc *xfrm_ealg_get_byname(char *name, int probe)
 579 {
 580         return xfrm_find_algo(&xfrm_ealg_list, xfrm_alg_name_match, name,
 581                               probe);
 582 }
 583 EXPORT_SYMBOL_GPL(xfrm_ealg_get_byname);
 584
 585 struct xfrm_algo_desc *xfrm_calg_get_byname(char *name, int probe)
 586 {
 587         return xfrm_find_algo(&xfrm_calg_list, xfrm_alg_name_match, name,
 588                               probe);
 589 }
 590 EXPORT_SYMBOL_GPL(xfrm_calg_get_byname);
 591
 592 struct xfrm_aead_name {
 593         const char *name;
 594         int icvbits;
 595 };
 596
 597 static int xfrm_aead_name_match(const struct xfrm_algo_desc *entry,
 598                                 const void *data)
 599 {
 600         const struct xfrm_aead_name *aead = data;
 601         const char *name = aead->name;
 602
 603         return aead->icvbits == entry->uinfo.aead.icv_truncbits && name &&
 604                !strcmp(name, entry->name);
 605 }
 606
 607 struct xfrm_algo_desc *xfrm_aead_get_byname(char *name, int icv_len, int probe)
 608 {
 609         struct xfrm_aead_name data = {
 610                 .name = name,
 611                 .icvbits = icv_len,
 612         };
 613
 614         return xfrm_find_algo(&xfrm_aead_list, xfrm_aead_name_match, &data,
 615                               probe);
 616 }
 617 EXPORT_SYMBOL_GPL(xfrm_aead_get_byname);
 618
 619 struct xfrm_algo_desc *xfrm_aalg_get_byidx(unsigned int idx)
 620 {
 621         if (idx >= aalg_entries())
 622                 return NULL;
 623
 624         return &aalg_list[idx];
 625 }
 626 EXPORT_SYMBOL_GPL(xfrm_aalg_get_byidx);
 627
 628 struct xfrm_algo_desc *xfrm_ealg_get_byidx(unsigned int idx)
 629 {
 630         if (idx >= ealg_entries())
 631                 return NULL;
 632
 633         return &ealg_list[idx];
 634 }
 635 EXPORT_SYMBOL_GPL(xfrm_ealg_get_byidx);
 636
 637 /*
 638  * Probe for the availability of crypto algorithms, and set the available
 639  * flag for any algorithms found on the system.  This is typically called by
 640  * pfkey during userspace SA add, update or register.
 641  */
 642 void xfrm_probe_algs(void)
 643 {
 644         int i, status;
 645
 646         BUG_ON(in_softirq());
 647
 648         for (i = 0; i < aalg_entries(); i++) {
 649                 status = crypto_has_hash(aalg_list[i].name, 0,
 650                                          CRYPTO_ALG_ASYNC);
 651                 if (aalg_list[i].available != status)
 652                         aalg_list[i].available = status;
 653         }
 654
 655         for (i = 0; i < ealg_entries(); i++) {
 656                 status = crypto_has_blkcipher(ealg_list[i].name, 0,
 657                                               CRYPTO_ALG_ASYNC);
 658                 if (ealg_list[i].available != status)
 659                         ealg_list[i].available = status;
 660         }
 661
 662         for (i = 0; i < calg_entries(); i++) {
 663                 status = crypto_has_comp(calg_list[i].name, 0,
 664                                          CRYPTO_ALG_ASYNC);
 665                 if (calg_list[i].available != status)
 666                         calg_list[i].available = status;
 667         }
 668 }
 669 EXPORT_SYMBOL_GPL(xfrm_probe_algs);
 670
 671 int xfrm_count_auth_supported(void)
 672 {
 673         int i, n;
 674
 675         for (i = 0, n = 0; i < aalg_entries(); i++)
 676                 if (aalg_list[i].available)
 677                         n++;
 678         return n;
 679 }
 680 EXPORT_SYMBOL_GPL(xfrm_count_auth_supported);
 681
 682 int xfrm_count_enc_supported(void)
 683 {
 684         int i, n;
 685
 686         for (i = 0, n = 0; i < ealg_entries(); i++)
 687                 if (ealg_list[i].available)
 688                         n++;
 689         return n;
 690 }
 691 EXPORT_SYMBOL_GPL(xfrm_count_enc_supported);
 692
 693 /* Move to common area: it is shared with AH. */
 694
 695 int skb_icv_walk(const struct sk_buff *skb, struct hash_desc *desc,
 696                  int offset, int len, icv_update_fn_t icv_update)
 697 {
 698         int start = skb_headlen(skb);
 699         int i, copy = start - offset;
 700         int err;
 701         struct scatterlist sg;
 702
 703         /* Checksum header. */
 704         if (copy > 0) {
 705                 if (copy > len)
 706                         copy = len;
 707
 708                 sg_init_one(&sg, skb->data + offset, copy);
 709
 710                 err = icv_update(desc, &sg, copy);
 711                 if (unlikely(err))
 712                         return err;
 713
 714                 if ((len -= copy) == 0)
 715                         return 0;
 716                 offset += copy;
 717         }
 718
 719         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 720                 int end;
 721
 722                 BUG_TRAP(start <= offset + len);
 723
 724                 end = start + skb_shinfo(skb)->frags[i].size;
 725                 if ((copy = end - offset) > 0) {
 726                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 727
 728                         if (copy > len)
 729                                 copy = len;
 730
 731                         sg_init_table(&sg, 1);
 732                         sg_set_page(&sg, frag->page, copy,
 733                                     frag->page_offset + offset-start);
 734
 735                         err = icv_update(desc, &sg, copy);
 736                         if (unlikely(err))
 737                                 return err;
 738
 739                         if (!(len -= copy))
 740                                 return 0;
 741                         offset += copy;
 742                 }
 743                 start = end;
 744         }
 745
 746         if (skb_shinfo(skb)->frag_list) {
 747                 struct sk_buff *list = skb_shinfo(skb)->frag_list;
 748
 749                 for (; list; list = list->next) {
 750                         int end;
 751
 752                         BUG_TRAP(start <= offset + len);
 753
 754                         end = start + list->len;
 755                         if ((copy = end - offset) > 0) {
 756                                 if (copy > len)
 757                                         copy = len;
 758                                 err = skb_icv_walk(list, desc, offset-start,
 759                                                    copy, icv_update);
 760                                 if (unlikely(err))
 761                                         return err;
 762                                 if ((len -= copy) == 0)
 763                                         return 0;
 764                                 offset += copy;
 765                         }
 766                         start = end;
 767                 }
 768         }
 769         BUG_ON(len);
 770         return 0;
 771 }
 772 EXPORT_SYMBOL_GPL(skb_icv_walk);
 773
 774 #if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)
 775
 776 void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
 777 {
 778         if (tail != skb) {
 779                 skb->data_len += len;
 780                 skb->len += len;
 781         }
 782         return skb_put(tail, len);
 783 }
 784 EXPORT_SYMBOL_GPL(pskb_put);
 785 #endif