net/ipv4/esp4.c

   1 #define pr_fmt(fmt) "IPsec: " fmt
   2
   3 #include <crypto/aead.h>
   4 #include <crypto/authenc.h>
   5 #include <linux/err.h>
   6 #include <linux/module.h>
   7 #include <net/ip.h>
   8 #include <net/xfrm.h>
   9 #include <net/esp.h>
  10 #include <linux/scatterlist.h>
  11 #include <linux/kernel.h>
  12 #include <linux/pfkeyv2.h>
  13 #include <linux/rtnetlink.h>
  14 #include <linux/slab.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/in6.h>
  17 #include <net/icmp.h>
  18 #include <net/protocol.h>
  19 #include <net/udp.h>
  20
  21 struct esp_skb_cb {
  22         struct xfrm_skb_cb xfrm;
  23         void *tmp;
  24 };
  25
  26 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
  27
  28 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
  29
  30 /*
  31  * Allocate an AEAD request structure with extra space for SG and IV.
  32  *
  33  * For alignment considerations the IV is placed at the front, followed
  34  * by the request and finally the SG list.
  35  *
  36  * TODO: Use spare space in skb for this where possible.
  37  */
  38 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
  39 {
  40         unsigned int len;
  41
  42         len = seqhilen;
  43
  44         len += crypto_aead_ivsize(aead);
  45
  46         if (len) {
  47                 len += crypto_aead_alignmask(aead) &
  48                        ~(crypto_tfm_ctx_alignment() - 1);
  49                 len = ALIGN(len, crypto_tfm_ctx_alignment());
  50         }
  51
  52         len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
  53         len = ALIGN(len, __alignof__(struct scatterlist));
  54
  55         len += sizeof(struct scatterlist) * nfrags;
  56
  57         return kmalloc(len, GFP_ATOMIC);
  58 }
  59
  60 static inline __be32 *esp_tmp_seqhi(void *tmp)
  61 {
  62         return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
  63 }
  64 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
  65 {
  66         return crypto_aead_ivsize(aead) ?
  67                PTR_ALIGN((u8 *)tmp + seqhilen,
  68                          crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
  69 }
  70
  71 static inline struct aead_givcrypt_request *esp_tmp_givreq(
  72         struct crypto_aead *aead, u8 *iv)
  73 {
  74         struct aead_givcrypt_request *req;
  75
  76         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
  77                                 crypto_tfm_ctx_alignment());
  78         aead_givcrypt_set_tfm(req, aead);
  79         return req;
  80 }
  81
  82 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
  83 {
  84         struct aead_request *req;
  85
  86         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
  87                                 crypto_tfm_ctx_alignment());
  88         aead_request_set_tfm(req, aead);
  89         return req;
  90 }
  91
  92 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
  93                                              struct aead_request *req)
  94 {
  95         return (void *)ALIGN((unsigned long)(req + 1) +
  96                              crypto_aead_reqsize(aead),
  97                              __alignof__(struct scatterlist));
  98 }
  99
 100 static inline struct scatterlist *esp_givreq_sg(
 101         struct crypto_aead *aead, struct aead_givcrypt_request *req)
 102 {
 103         return (void *)ALIGN((unsigned long)(req + 1) +
 104                              crypto_aead_reqsize(aead),
 105                              __alignof__(struct scatterlist));
 106 }
 107
 108 static void esp_output_done(struct crypto_async_request *base, int err)
 109 {
 110         struct sk_buff *skb = base->data;
 111
 112         kfree(ESP_SKB_CB(skb)->tmp);
 113         xfrm_output_resume(skb, err);
 114 }
 115
 116 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 117 {
 118         int err;
 119         struct ip_esp_hdr *esph;
 120         struct crypto_aead *aead;
 121         struct aead_givcrypt_request *req;
 122         struct scatterlist *sg;
 123         struct scatterlist *asg;
 124         struct sk_buff *trailer;
 125         void *tmp;
 126         u8 *iv;
 127         u8 *tail;
 128         int blksize;
 129         int clen;
 130         int alen;
 131         int plen;
 132         int tfclen;
 133         int nfrags;
 134         int assoclen;
 135         int sglists;
 136         int seqhilen;
 137         __be32 *seqhi;
 138
 139         /* skb is pure payload to encrypt */
 140
 141         aead = x->data;
 142         alen = crypto_aead_authsize(aead);
 143
 144         tfclen = 0;
 145         if (x->tfcpad) {
 146                 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
 147                 u32 padto;
 148
 149                 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
 150                 if (skb->len < padto)
 151                         tfclen = padto - skb->len;
 152         }
 153         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 154         clen = ALIGN(skb->len + 2 + tfclen, blksize);
 155         plen = clen - skb->len - tfclen;
 156
 157         err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
 158         if (err < 0)
 159                 goto error;
 160         nfrags = err;
 161
 162         assoclen = sizeof(*esph);
 163         sglists = 1;
 164         seqhilen = 0;
 165
 166         if (x->props.flags & XFRM_STATE_ESN) {
 167                 sglists += 2;
 168                 seqhilen += sizeof(__be32);
 169                 assoclen += seqhilen;
 170         }
 171
 172         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 173         if (!tmp) {
 174                 err = -ENOMEM;
 175                 goto error;
 176         }
 177
 178         seqhi = esp_tmp_seqhi(tmp);
 179         iv = esp_tmp_iv(aead, tmp, seqhilen);
 180         req = esp_tmp_givreq(aead, iv);
 181         asg = esp_givreq_sg(aead, req);
 182         sg = asg + sglists;
 183
 184         /* Fill padding... */
 185         tail = skb_tail_pointer(trailer);
 186         if (tfclen) {
 187                 memset(tail, 0, tfclen);
 188                 tail += tfclen;
 189         }
 190         do {
 191                 int i;
 192                 for (i = 0; i < plen - 2; i++)
 193                         tail[i] = i + 1;
 194         } while (0);
 195         tail[plen - 2] = plen - 2;
 196         tail[plen - 1] = *skb_mac_header(skb);
 197         pskb_put(skb, trailer, clen - skb->len + alen);
 198
 199         skb_push(skb, -skb_network_offset(skb));
 200         esph = ip_esp_hdr(skb);
 201         *skb_mac_header(skb) = IPPROTO_ESP;
 202
 203         /* this is non-NULL only with UDP Encapsulation */
 204         if (x->encap) {
 205                 struct xfrm_encap_tmpl *encap = x->encap;
 206                 struct udphdr *uh;
 207                 __be32 *udpdata32;
 208                 __be16 sport, dport;
 209                 int encap_type;
 210
 211                 spin_lock_bh(&x->lock);
 212                 sport = encap->encap_sport;
 213                 dport = encap->encap_dport;
 214                 encap_type = encap->encap_type;
 215                 spin_unlock_bh(&x->lock);
 216
 217                 uh = (struct udphdr *)esph;
 218                 uh->source = sport;
 219                 uh->dest = dport;
 220                 uh->len = htons(skb->len - skb_transport_offset(skb));
 221                 uh->check = 0;
 222
 223                 switch (encap_type) {
 224                 default:
 225                 case UDP_ENCAP_ESPINUDP:
 226                         esph = (struct ip_esp_hdr *)(uh + 1);
 227                         break;
 228                 case UDP_ENCAP_ESPINUDP_NON_IKE:
 229                         udpdata32 = (__be32 *)(uh + 1);
 230                         udpdata32[0] = udpdata32[1] = 0;
 231                         esph = (struct ip_esp_hdr *)(udpdata32 + 2);
 232                         break;
 233                 }
 234
 235                 *skb_mac_header(skb) = IPPROTO_UDP;
 236         }
 237
 238         esph->spi = x->id.spi;
 239         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 240
 241         sg_init_table(sg, nfrags);
 242         skb_to_sgvec(skb, sg,
 243                      esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
 244                      clen + alen);
 245
 246         if ((x->props.flags & XFRM_STATE_ESN)) {
 247                 sg_init_table(asg, 3);
 248                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 249                 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
 250                 sg_set_buf(asg + 1, seqhi, seqhilen);
 251                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 252         } else
 253                 sg_init_one(asg, esph, sizeof(*esph));
 254
 255         aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
 256         aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
 257         aead_givcrypt_set_assoc(req, asg, assoclen);
 258         aead_givcrypt_set_giv(req, esph->enc_data,
 259                               XFRM_SKB_CB(skb)->seq.output.low);
 260
 261         ESP_SKB_CB(skb)->tmp = tmp;
 262         err = crypto_aead_givencrypt(req);
 263         if (err == -EINPROGRESS)
 264                 goto error;
 265
 266         if (err == -EBUSY)
 267                 err = NET_XMIT_DROP;
 268
 269         kfree(tmp);
 270
 271 error:
 272         return err;
 273 }
 274
 275 static int esp_input_done2(struct sk_buff *skb, int err)
 276 {
 277         const struct iphdr *iph;
 278         struct xfrm_state *x = xfrm_input_state(skb);
 279         struct crypto_aead *aead = x->data;
 280         int alen = crypto_aead_authsize(aead);
 281         int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 282         int elen = skb->len - hlen;
 283         int ihl;
 284         u8 nexthdr[2];
 285         int padlen;
 286
 287         kfree(ESP_SKB_CB(skb)->tmp);
 288
 289         if (unlikely(err))
 290                 goto out;
 291
 292         if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
 293                 BUG();
 294
 295         err = -EINVAL;
 296         padlen = nexthdr[0];
 297         if (padlen + 2 + alen >= elen)
 298                 goto out;
 299
 300         /* ... check padding bits here. Silly. :-) */
 301
 302         iph = ip_hdr(skb);
 303         ihl = iph->ihl * 4;
 304
 305         if (x->encap) {
 306                 struct xfrm_encap_tmpl *encap = x->encap;
 307                 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
 308
 309                 /*
 310                  * 1) if the NAT-T peer's IP or port changed then
 311                  *    advertize the change to the keying daemon.
 312                  *    This is an inbound SA, so just compare
 313                  *    SRC ports.
 314                  */
 315                 if (iph->saddr != x->props.saddr.a4 ||
 316                     uh->source != encap->encap_sport) {
 317                         xfrm_address_t ipaddr;
 318
 319                         ipaddr.a4 = iph->saddr;
 320                         km_new_mapping(x, &ipaddr, uh->source);
 321
 322                         /* XXX: perhaps add an extra
 323                          * policy check here, to see
 324                          * if we should allow or
 325                          * reject a packet from a
 326                          * different source
 327                          * address/port.
 328                          */
 329                 }
 330
 331                 /*
 332                  * 2) ignore UDP/TCP checksums in case
 333                  *    of NAT-T in Transport Mode, or
 334                  *    perform other post-processing fixes
 335                  *    as per draft-ietf-ipsec-udp-encaps-06,
 336                  *    section 3.1.2
 337                  */
 338                 if (x->props.mode == XFRM_MODE_TRANSPORT)
 339                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 340         }
 341
 342         pskb_trim(skb, skb->len - alen - padlen - 2);
 343         __skb_pull(skb, hlen);
 344         if (x->props.mode == XFRM_MODE_TUNNEL)
 345                 skb_reset_transport_header(skb);
 346         else
 347                 skb_set_transport_header(skb, -ihl);
 348
 349         err = nexthdr[1];
 350
 351         /* RFC4303: Drop dummy packets without any error */
 352         if (err == IPPROTO_NONE)
 353                 err = -EINVAL;
 354
 355 out:
 356         return err;
 357 }
 358
 359 static void esp_input_done(struct crypto_async_request *base, int err)
 360 {
 361         struct sk_buff *skb = base->data;
 362
 363         xfrm_input_resume(skb, esp_input_done2(skb, err));
 364 }
 365
 366 /*
 367  * Note: detecting truncated vs. non-truncated authentication data is very
 368  * expensive, so we only support truncated data, which is the recommended
 369  * and common case.
 370  */
 371 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
 372 {
 373         struct ip_esp_hdr *esph;
 374         struct crypto_aead *aead = x->data;
 375         struct aead_request *req;
 376         struct sk_buff *trailer;
 377         int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
 378         int nfrags;
 379         int assoclen;
 380         int sglists;
 381         int seqhilen;
 382         __be32 *seqhi;
 383         void *tmp;
 384         u8 *iv;
 385         struct scatterlist *sg;
 386         struct scatterlist *asg;
 387         int err = -EINVAL;
 388
 389         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 390                 goto out;
 391
 392         if (elen <= 0)
 393                 goto out;
 394
 395         err = skb_cow_data(skb, 0, &trailer);
 396         if (err < 0)
 397                 goto out;
 398
 399         nfrags = err;
 400
 401         assoclen = sizeof(*esph);
 402         sglists = 1;
 403         seqhilen = 0;
 404
 405         if (x->props.flags & XFRM_STATE_ESN) {
 406                 sglists += 2;
 407                 seqhilen += sizeof(__be32);
 408                 assoclen += seqhilen;
 409         }
 410
 411         err = -ENOMEM;
 412         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 413         if (!tmp)
 414                 goto out;
 415
 416         ESP_SKB_CB(skb)->tmp = tmp;
 417         seqhi = esp_tmp_seqhi(tmp);
 418         iv = esp_tmp_iv(aead, tmp, seqhilen);
 419         req = esp_tmp_req(aead, iv);
 420         asg = esp_req_sg(aead, req);
 421         sg = asg + sglists;
 422
 423         skb->ip_summed = CHECKSUM_NONE;
 424
 425         esph = (struct ip_esp_hdr *)skb->data;
 426
 427         /* Get ivec. This can be wrong, check against another impls. */
 428         iv = esph->enc_data;
 429
 430         sg_init_table(sg, nfrags);
 431         skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
 432
 433         if ((x->props.flags & XFRM_STATE_ESN)) {
 434                 sg_init_table(asg, 3);
 435                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 436                 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
 437                 sg_set_buf(asg + 1, seqhi, seqhilen);
 438                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 439         } else
 440                 sg_init_one(asg, esph, sizeof(*esph));
 441
 442         aead_request_set_callback(req, 0, esp_input_done, skb);
 443         aead_request_set_crypt(req, sg, sg, elen, iv);
 444         aead_request_set_assoc(req, asg, assoclen);
 445
 446         err = crypto_aead_decrypt(req);
 447         if (err == -EINPROGRESS)
 448                 goto out;
 449
 450         err = esp_input_done2(skb, err);
 451
 452 out:
 453         return err;
 454 }
 455
 456 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
 457 {
 458         struct crypto_aead *aead = x->data;
 459         u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 460         unsigned int net_adj;
 461
 462         switch (x->props.mode) {
 463         case XFRM_MODE_TRANSPORT:
 464         case XFRM_MODE_BEET:
 465                 net_adj = sizeof(struct iphdr);
 466                 break;
 467         case XFRM_MODE_TUNNEL:
 468                 net_adj = 0;
 469                 break;
 470         default:
 471                 BUG();
 472         }
 473
 474         return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
 475                  net_adj) & ~(blksize - 1)) + net_adj - 2;
 476 }
 477
 478 static int esp4_err(struct sk_buff *skb, u32 info)
 479 {
 480         struct net *net = dev_net(skb->dev);
 481         const struct iphdr *iph = (const struct iphdr *)skb->data;
 482         struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 483         struct xfrm_state *x;
 484
 485         switch (icmp_hdr(skb)->type) {
 486         case ICMP_DEST_UNREACH:
 487                 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 488                         return 0;
 489         case ICMP_REDIRECT:
 490                 break;
 491         default:
 492                 return 0;
 493         }
 494
 495         x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
 496                               esph->spi, IPPROTO_ESP, AF_INET);
 497         if (!x)
 498                 return 0;
 499
 500         if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
 501                 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
 502         else
 503                 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
 504         xfrm_state_put(x);
 505
 506         return 0;
 507 }
 508
 509 static void esp_destroy(struct xfrm_state *x)
 510 {
 511         struct crypto_aead *aead = x->data;
 512
 513         if (!aead)
 514                 return;
 515
 516         crypto_free_aead(aead);
 517 }
 518
 519 static int esp_init_aead(struct xfrm_state *x)
 520 {
 521         struct crypto_aead *aead;
 522         int err;
 523
 524         aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
 525         err = PTR_ERR(aead);
 526         if (IS_ERR(aead))
 527                 goto error;
 528
 529         x->data = aead;
 530
 531         err = crypto_aead_setkey(aead, x->aead->alg_key,
 532                                  (x->aead->alg_key_len + 7) / 8);
 533         if (err)
 534                 goto error;
 535
 536         err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
 537         if (err)
 538                 goto error;
 539
 540 error:
 541         return err;
 542 }
 543
 544 static int esp_init_authenc(struct xfrm_state *x)
 545 {
 546         struct crypto_aead *aead;
 547         struct crypto_authenc_key_param *param;
 548         struct rtattr *rta;
 549         char *key;
 550         char *p;
 551         char authenc_name[CRYPTO_MAX_ALG_NAME];
 552         unsigned int keylen;
 553         int err;
 554
 555         err = -EINVAL;
 556         if (!x->ealg)
 557                 goto error;
 558
 559         err = -ENAMETOOLONG;
 560
 561         if ((x->props.flags & XFRM_STATE_ESN)) {
 562                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 563                              "authencesn(%s,%s)",
 564                              x->aalg ? x->aalg->alg_name : "digest_null",
 565                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 566                         goto error;
 567         } else {
 568                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 569                              "authenc(%s,%s)",
 570                              x->aalg ? x->aalg->alg_name : "digest_null",
 571                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 572                         goto error;
 573         }
 574
 575         aead = crypto_alloc_aead(authenc_name, 0, 0);
 576         err = PTR_ERR(aead);
 577         if (IS_ERR(aead))
 578                 goto error;
 579
 580         x->data = aead;
 581
 582         keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
 583                  (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
 584         err = -ENOMEM;
 585         key = kmalloc(keylen, GFP_KERNEL);
 586         if (!key)
 587                 goto error;
 588
 589         p = key;
 590         rta = (void *)p;
 591         rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
 592         rta->rta_len = RTA_LENGTH(sizeof(*param));
 593         param = RTA_DATA(rta);
 594         p += RTA_SPACE(sizeof(*param));
 595
 596         if (x->aalg) {
 597                 struct xfrm_algo_desc *aalg_desc;
 598
 599                 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
 600                 p += (x->aalg->alg_key_len + 7) / 8;
 601
 602                 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
 603                 BUG_ON(!aalg_desc);
 604
 605                 err = -EINVAL;
 606                 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
 607                     crypto_aead_authsize(aead)) {
 608                         pr_info("ESP: %s digestsize %u != %hu\n",
 609                                 x->aalg->alg_name,
 610                                 crypto_aead_authsize(aead),
 611                                 aalg_desc->uinfo.auth.icv_fullbits / 8);
 612                         goto free_key;
 613                 }
 614
 615                 err = crypto_aead_setauthsize(
 616                         aead, x->aalg->alg_trunc_len / 8);
 617                 if (err)
 618                         goto free_key;
 619         }
 620
 621         param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
 622         memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
 623
 624         err = crypto_aead_setkey(aead, key, keylen);
 625
 626 free_key:
 627         kfree(key);
 628
 629 error:
 630         return err;
 631 }
 632
 633 static int esp_init_state(struct xfrm_state *x)
 634 {
 635         struct crypto_aead *aead;
 636         u32 align;
 637         int err;
 638
 639         x->data = NULL;
 640
 641         if (x->aead)
 642                 err = esp_init_aead(x);
 643         else
 644                 err = esp_init_authenc(x);
 645
 646         if (err)
 647                 goto error;
 648
 649         aead = x->data;
 650
 651         x->props.header_len = sizeof(struct ip_esp_hdr) +
 652                               crypto_aead_ivsize(aead);
 653         if (x->props.mode == XFRM_MODE_TUNNEL)
 654                 x->props.header_len += sizeof(struct iphdr);
 655         else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
 656                 x->props.header_len += IPV4_BEET_PHMAXLEN;
 657         if (x->encap) {
 658                 struct xfrm_encap_tmpl *encap = x->encap;
 659
 660                 switch (encap->encap_type) {
 661                 default:
 662                         goto error;
 663                 case UDP_ENCAP_ESPINUDP:
 664                         x->props.header_len += sizeof(struct udphdr);
 665                         break;
 666                 case UDP_ENCAP_ESPINUDP_NON_IKE:
 667                         x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
 668                         break;
 669                 }
 670         }
 671
 672         align = ALIGN(crypto_aead_blocksize(aead), 4);
 673         x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
 674
 675 error:
 676         return err;
 677 }
 678
 679 static int esp4_rcv_cb(struct sk_buff *skb, int err)
 680 {
 681         return 0;
 682 }
 683
 684 static const struct xfrm_type esp_type =
 685 {
 686         .description    = "ESP4",
 687         .owner          = THIS_MODULE,
 688         .proto          = IPPROTO_ESP,
 689         .flags          = XFRM_TYPE_REPLAY_PROT,
 690         .init_state     = esp_init_state,
 691         .destructor     = esp_destroy,
 692         .get_mtu        = esp4_get_mtu,
 693         .input          = esp_input,
 694         .output         = esp_output
 695 };
 696
 697 static struct xfrm4_protocol esp4_protocol = {
 698         .handler        =       xfrm4_rcv,
 699         .input_handler  =       xfrm_input,
 700         .cb_handler     =       esp4_rcv_cb,
 701         .err_handler    =       esp4_err,
 702         .priority       =       0,
 703 };
 704
 705 static int __init esp4_init(void)
 706 {
 707         if (xfrm_register_type(&esp_type, AF_INET) < 0) {
 708                 pr_info("%s: can't add xfrm type\n", __func__);
 709                 return -EAGAIN;
 710         }
 711         if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
 712                 pr_info("%s: can't add protocol\n", __func__);
 713                 xfrm_unregister_type(&esp_type, AF_INET);
 714                 return -EAGAIN;
 715         }
 716         return 0;
 717 }
 718
 719 static void __exit esp4_fini(void)
 720 {
 721         if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
 722                 pr_info("%s: can't remove protocol\n", __func__);
 723         if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
 724                 pr_info("%s: can't remove xfrm type\n", __func__);
 725 }
 726
 727 module_init(esp4_init);
 728 module_exit(esp4_fini);
 729 MODULE_LICENSE("GPL");
 730 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);