net/ipv4/esp4.c

   1 #include <crypto/aead.h>
   2 #include <crypto/authenc.h>
   3 #include <linux/err.h>
   4 #include <linux/module.h>
   5 #include <net/ip.h>
   6 #include <net/xfrm.h>
   7 #include <net/esp.h>
   8 #include <linux/scatterlist.h>
   9 #include <linux/kernel.h>
  10 #include <linux/pfkeyv2.h>
  11 #include <linux/rtnetlink.h>
  12 #include <linux/slab.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/in6.h>
  15 #include <net/icmp.h>
  16 #include <net/protocol.h>
  17 #include <net/udp.h>
  18
  19 struct esp_skb_cb {
  20         struct xfrm_skb_cb xfrm;
  21         void *tmp;
  22 };
  23
  24 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
  25
  26 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
  27
  28 /*
  29  * Allocate an AEAD request structure with extra space for SG and IV.
  30  *
  31  * For alignment considerations the IV is placed at the front, followed
  32  * by the request and finally the SG list.
  33  *
  34  * TODO: Use spare space in skb for this where possible.
  35  */
  36 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
  37 {
  38         unsigned int len;
  39
  40         len = seqhilen;
  41
  42         len += crypto_aead_ivsize(aead);
  43
  44         if (len) {
  45                 len += crypto_aead_alignmask(aead) &
  46                        ~(crypto_tfm_ctx_alignment() - 1);
  47                 len = ALIGN(len, crypto_tfm_ctx_alignment());
  48         }
  49
  50         len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
  51         len = ALIGN(len, __alignof__(struct scatterlist));
  52
  53         len += sizeof(struct scatterlist) * nfrags;
  54
  55         return kmalloc(len, GFP_ATOMIC);
  56 }
  57
  58 static inline __be32 *esp_tmp_seqhi(void *tmp)
  59 {
  60         return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
  61 }
  62 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
  63 {
  64         return crypto_aead_ivsize(aead) ?
  65                PTR_ALIGN((u8 *)tmp + seqhilen,
  66                          crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
  67 }
  68
  69 static inline struct aead_givcrypt_request *esp_tmp_givreq(
  70         struct crypto_aead *aead, u8 *iv)
  71 {
  72         struct aead_givcrypt_request *req;
  73
  74         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
  75                                 crypto_tfm_ctx_alignment());
  76         aead_givcrypt_set_tfm(req, aead);
  77         return req;
  78 }
  79
  80 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
  81 {
  82         struct aead_request *req;
  83
  84         req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
  85                                 crypto_tfm_ctx_alignment());
  86         aead_request_set_tfm(req, aead);
  87         return req;
  88 }
  89
  90 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
  91                                              struct aead_request *req)
  92 {
  93         return (void *)ALIGN((unsigned long)(req + 1) +
  94                              crypto_aead_reqsize(aead),
  95                              __alignof__(struct scatterlist));
  96 }
  97
  98 static inline struct scatterlist *esp_givreq_sg(
  99         struct crypto_aead *aead, struct aead_givcrypt_request *req)
 100 {
 101         return (void *)ALIGN((unsigned long)(req + 1) +
 102                              crypto_aead_reqsize(aead),
 103                              __alignof__(struct scatterlist));
 104 }
 105
 106 static void esp_output_done(struct crypto_async_request *base, int err)
 107 {
 108         struct sk_buff *skb = base->data;
 109
 110         kfree(ESP_SKB_CB(skb)->tmp);
 111         xfrm_output_resume(skb, err);
 112 }
 113
 114 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 115 {
 116         int err;
 117         struct ip_esp_hdr *esph;
 118         struct crypto_aead *aead;
 119         struct aead_givcrypt_request *req;
 120         struct scatterlist *sg;
 121         struct scatterlist *asg;
 122         struct esp_data *esp;
 123         struct sk_buff *trailer;
 124         void *tmp;
 125         u8 *iv;
 126         u8 *tail;
 127         int blksize;
 128         int clen;
 129         int alen;
 130         int plen;
 131         int tfclen;
 132         int nfrags;
 133         int assoclen;
 134         int sglists;
 135         int seqhilen;
 136         __be32 *seqhi;
 137
 138         /* skb is pure payload to encrypt */
 139
 140         err = -ENOMEM;
 141
 142         esp = x->data;
 143         aead = esp->aead;
 144         alen = crypto_aead_authsize(aead);
 145
 146         tfclen = 0;
 147         if (x->tfcpad) {
 148                 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
 149                 u32 padto;
 150
 151                 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
 152                 if (skb->len < padto)
 153                         tfclen = padto - skb->len;
 154         }
 155         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 156         clen = ALIGN(skb->len + 2 + tfclen, blksize);
 157         if (esp->padlen)
 158                 clen = ALIGN(clen, esp->padlen);
 159         plen = clen - skb->len - tfclen;
 160
 161         err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
 162         if (err < 0)
 163                 goto error;
 164         nfrags = err;
 165
 166         assoclen = sizeof(*esph);
 167         sglists = 1;
 168         seqhilen = 0;
 169
 170         if (x->props.flags & XFRM_STATE_ESN) {
 171                 sglists += 2;
 172                 seqhilen += sizeof(__be32);
 173                 assoclen += seqhilen;
 174         }
 175
 176         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 177         if (!tmp)
 178                 goto error;
 179
 180         seqhi = esp_tmp_seqhi(tmp);
 181         iv = esp_tmp_iv(aead, tmp, seqhilen);
 182         req = esp_tmp_givreq(aead, iv);
 183         asg = esp_givreq_sg(aead, req);
 184         sg = asg + sglists;
 185
 186         /* Fill padding... */
 187         tail = skb_tail_pointer(trailer);
 188         if (tfclen) {
 189                 memset(tail, 0, tfclen);
 190                 tail += tfclen;
 191         }
 192         do {
 193                 int i;
 194                 for (i = 0; i < plen - 2; i++)
 195                         tail[i] = i + 1;
 196         } while (0);
 197         tail[plen - 2] = plen - 2;
 198         tail[plen - 1] = *skb_mac_header(skb);
 199         pskb_put(skb, trailer, clen - skb->len + alen);
 200
 201         skb_push(skb, -skb_network_offset(skb));
 202         esph = ip_esp_hdr(skb);
 203         *skb_mac_header(skb) = IPPROTO_ESP;
 204
 205         /* this is non-NULL only with UDP Encapsulation */
 206         if (x->encap) {
 207                 struct xfrm_encap_tmpl *encap = x->encap;
 208                 struct udphdr *uh;
 209                 __be32 *udpdata32;
 210                 __be16 sport, dport;
 211                 int encap_type;
 212
 213                 spin_lock_bh(&x->lock);
 214                 sport = encap->encap_sport;
 215                 dport = encap->encap_dport;
 216                 encap_type = encap->encap_type;
 217                 spin_unlock_bh(&x->lock);
 218
 219                 uh = (struct udphdr *)esph;
 220                 uh->source = sport;
 221                 uh->dest = dport;
 222                 uh->len = htons(skb->len - skb_transport_offset(skb));
 223                 uh->check = 0;
 224
 225                 switch (encap_type) {
 226                 default:
 227                 case UDP_ENCAP_ESPINUDP:
 228                         esph = (struct ip_esp_hdr *)(uh + 1);
 229                         break;
 230                 case UDP_ENCAP_ESPINUDP_NON_IKE:
 231                         udpdata32 = (__be32 *)(uh + 1);
 232                         udpdata32[0] = udpdata32[1] = 0;
 233                         esph = (struct ip_esp_hdr *)(udpdata32 + 2);
 234                         break;
 235                 }
 236
 237                 *skb_mac_header(skb) = IPPROTO_UDP;
 238         }
 239
 240         esph->spi = x->id.spi;
 241         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 242
 243         sg_init_table(sg, nfrags);
 244         skb_to_sgvec(skb, sg,
 245                      esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
 246                      clen + alen);
 247
 248         if ((x->props.flags & XFRM_STATE_ESN)) {
 249                 sg_init_table(asg, 3);
 250                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 251                 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
 252                 sg_set_buf(asg + 1, seqhi, seqhilen);
 253                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 254         } else
 255                 sg_init_one(asg, esph, sizeof(*esph));
 256
 257         aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
 258         aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
 259         aead_givcrypt_set_assoc(req, asg, assoclen);
 260         aead_givcrypt_set_giv(req, esph->enc_data,
 261                               XFRM_SKB_CB(skb)->seq.output.low);
 262
 263         ESP_SKB_CB(skb)->tmp = tmp;
 264         err = crypto_aead_givencrypt(req);
 265         if (err == -EINPROGRESS)
 266                 goto error;
 267
 268         if (err == -EBUSY)
 269                 err = NET_XMIT_DROP;
 270
 271         kfree(tmp);
 272
 273 error:
 274         return err;
 275 }
 276
 277 static int esp_input_done2(struct sk_buff *skb, int err)
 278 {
 279         const struct iphdr *iph;
 280         struct xfrm_state *x = xfrm_input_state(skb);
 281         struct esp_data *esp = x->data;
 282         struct crypto_aead *aead = esp->aead;
 283         int alen = crypto_aead_authsize(aead);
 284         int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 285         int elen = skb->len - hlen;
 286         int ihl;
 287         u8 nexthdr[2];
 288         int padlen;
 289
 290         kfree(ESP_SKB_CB(skb)->tmp);
 291
 292         if (unlikely(err))
 293                 goto out;
 294
 295         if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
 296                 BUG();
 297
 298         err = -EINVAL;
 299         padlen = nexthdr[0];
 300         if (padlen + 2 + alen >= elen)
 301                 goto out;
 302
 303         /* ... check padding bits here. Silly. :-) */
 304
 305         iph = ip_hdr(skb);
 306         ihl = iph->ihl * 4;
 307
 308         if (x->encap) {
 309                 struct xfrm_encap_tmpl *encap = x->encap;
 310                 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
 311
 312                 /*
 313                  * 1) if the NAT-T peer's IP or port changed then
 314                  *    advertize the change to the keying daemon.
 315                  *    This is an inbound SA, so just compare
 316                  *    SRC ports.
 317                  */
 318                 if (iph->saddr != x->props.saddr.a4 ||
 319                     uh->source != encap->encap_sport) {
 320                         xfrm_address_t ipaddr;
 321
 322                         ipaddr.a4 = iph->saddr;
 323                         km_new_mapping(x, &ipaddr, uh->source);
 324
 325                         /* XXX: perhaps add an extra
 326                          * policy check here, to see
 327                          * if we should allow or
 328                          * reject a packet from a
 329                          * different source
 330                          * address/port.
 331                          */
 332                 }
 333
 334                 /*
 335                  * 2) ignore UDP/TCP checksums in case
 336                  *    of NAT-T in Transport Mode, or
 337                  *    perform other post-processing fixes
 338                  *    as per draft-ietf-ipsec-udp-encaps-06,
 339                  *    section 3.1.2
 340                  */
 341                 if (x->props.mode == XFRM_MODE_TRANSPORT)
 342                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 343         }
 344
 345         pskb_trim(skb, skb->len - alen - padlen - 2);
 346         __skb_pull(skb, hlen);
 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 esp_data *esp = x->data;
 375         struct crypto_aead *aead = esp->aead;
 376         struct aead_request *req;
 377         struct sk_buff *trailer;
 378         int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
 379         int nfrags;
 380         int assoclen;
 381         int sglists;
 382         int seqhilen;
 383         __be32 *seqhi;
 384         void *tmp;
 385         u8 *iv;
 386         struct scatterlist *sg;
 387         struct scatterlist *asg;
 388         int err = -EINVAL;
 389
 390         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 391                 goto out;
 392
 393         if (elen <= 0)
 394                 goto out;
 395
 396         if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
 397                 goto out;
 398         nfrags = err;
 399
 400         assoclen = sizeof(*esph);
 401         sglists = 1;
 402         seqhilen = 0;
 403
 404         if (x->props.flags & XFRM_STATE_ESN) {
 405                 sglists += 2;
 406                 seqhilen += sizeof(__be32);
 407                 assoclen += seqhilen;
 408         }
 409
 410         err = -ENOMEM;
 411         tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 412         if (!tmp)
 413                 goto out;
 414
 415         ESP_SKB_CB(skb)->tmp = tmp;
 416         seqhi = esp_tmp_seqhi(tmp);
 417         iv = esp_tmp_iv(aead, tmp, seqhilen);
 418         req = esp_tmp_req(aead, iv);
 419         asg = esp_req_sg(aead, req);
 420         sg = asg + sglists;
 421
 422         skb->ip_summed = CHECKSUM_NONE;
 423
 424         esph = (struct ip_esp_hdr *)skb->data;
 425
 426         /* Get ivec. This can be wrong, check against another impls. */
 427         iv = esph->enc_data;
 428
 429         sg_init_table(sg, nfrags);
 430         skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
 431
 432         if ((x->props.flags & XFRM_STATE_ESN)) {
 433                 sg_init_table(asg, 3);
 434                 sg_set_buf(asg, &esph->spi, sizeof(__be32));
 435                 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
 436                 sg_set_buf(asg + 1, seqhi, seqhilen);
 437                 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 438         } else
 439                 sg_init_one(asg, esph, sizeof(*esph));
 440
 441         aead_request_set_callback(req, 0, esp_input_done, skb);
 442         aead_request_set_crypt(req, sg, sg, elen, iv);
 443         aead_request_set_assoc(req, asg, assoclen);
 444
 445         err = crypto_aead_decrypt(req);
 446         if (err == -EINPROGRESS)
 447                 goto out;
 448
 449         err = esp_input_done2(skb, err);
 450
 451 out:
 452         return err;
 453 }
 454
 455 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
 456 {
 457         struct esp_data *esp = x->data;
 458         u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
 459         u32 align = max_t(u32, blksize, esp->padlen);
 460         u32 rem;
 461
 462         mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
 463         rem = mtu & (align - 1);
 464         mtu &= ~(align - 1);
 465
 466         switch (x->props.mode) {
 467         case XFRM_MODE_TUNNEL:
 468                 break;
 469         default:
 470         case XFRM_MODE_TRANSPORT:
 471                 /* The worst case */
 472                 mtu -= blksize - 4;
 473                 mtu += min_t(u32, blksize - 4, rem);
 474                 break;
 475         case XFRM_MODE_BEET:
 476                 /* The worst case. */
 477                 mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
 478                 break;
 479         }
 480
 481         return mtu - 2;
 482 }
 483
 484 static void esp4_err(struct sk_buff *skb, u32 info)
 485 {
 486         struct net *net = dev_net(skb->dev);
 487         const struct iphdr *iph = (const struct iphdr *)skb->data;
 488         struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 489         struct xfrm_state *x;
 490
 491         if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
 492             icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 493                 return;
 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;
 499         NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
 500                  ntohl(esph->spi), ntohl(iph->daddr));
 501         xfrm_state_put(x);
 502 }
 503
 504 static void esp_destroy(struct xfrm_state *x)
 505 {
 506         struct esp_data *esp = x->data;
 507
 508         if (!esp)
 509                 return;
 510
 511         crypto_free_aead(esp->aead);
 512         kfree(esp);
 513 }
 514
 515 static int esp_init_aead(struct xfrm_state *x)
 516 {
 517         struct esp_data *esp = x->data;
 518         struct crypto_aead *aead;
 519         int err;
 520
 521         aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
 522         err = PTR_ERR(aead);
 523         if (IS_ERR(aead))
 524                 goto error;
 525
 526         esp->aead = aead;
 527
 528         err = crypto_aead_setkey(aead, x->aead->alg_key,
 529                                  (x->aead->alg_key_len + 7) / 8);
 530         if (err)
 531                 goto error;
 532
 533         err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
 534         if (err)
 535                 goto error;
 536
 537 error:
 538         return err;
 539 }
 540
 541 static int esp_init_authenc(struct xfrm_state *x)
 542 {
 543         struct esp_data *esp = x->data;
 544         struct crypto_aead *aead;
 545         struct crypto_authenc_key_param *param;
 546         struct rtattr *rta;
 547         char *key;
 548         char *p;
 549         char authenc_name[CRYPTO_MAX_ALG_NAME];
 550         unsigned int keylen;
 551         int err;
 552
 553         err = -EINVAL;
 554         if (x->ealg == NULL)
 555                 goto error;
 556
 557         err = -ENAMETOOLONG;
 558
 559         if ((x->props.flags & XFRM_STATE_ESN)) {
 560                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 561                              "authencesn(%s,%s)",
 562                              x->aalg ? x->aalg->alg_name : "digest_null",
 563                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 564                         goto error;
 565         } else {
 566                 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 567                              "authenc(%s,%s)",
 568                              x->aalg ? x->aalg->alg_name : "digest_null",
 569                              x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 570                         goto error;
 571         }
 572
 573         aead = crypto_alloc_aead(authenc_name, 0, 0);
 574         err = PTR_ERR(aead);
 575         if (IS_ERR(aead))
 576                 goto error;
 577
 578         esp->aead = aead;
 579
 580         keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
 581                  (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
 582         err = -ENOMEM;
 583         key = kmalloc(keylen, GFP_KERNEL);
 584         if (!key)
 585                 goto error;
 586
 587         p = key;
 588         rta = (void *)p;
 589         rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
 590         rta->rta_len = RTA_LENGTH(sizeof(*param));
 591         param = RTA_DATA(rta);
 592         p += RTA_SPACE(sizeof(*param));
 593
 594         if (x->aalg) {
 595                 struct xfrm_algo_desc *aalg_desc;
 596
 597                 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
 598                 p += (x->aalg->alg_key_len + 7) / 8;
 599
 600                 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
 601                 BUG_ON(!aalg_desc);
 602
 603                 err = -EINVAL;
 604                 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
 605                     crypto_aead_authsize(aead)) {
 606                         NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
 607                                  x->aalg->alg_name,
 608                                  crypto_aead_authsize(aead),
 609                                  aalg_desc->uinfo.auth.icv_fullbits/8);
 610                         goto free_key;
 611                 }
 612
 613                 err = crypto_aead_setauthsize(
 614                         aead, x->aalg->alg_trunc_len / 8);
 615                 if (err)
 616                         goto free_key;
 617         }
 618
 619         param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
 620         memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
 621
 622         err = crypto_aead_setkey(aead, key, keylen);
 623
 624 free_key:
 625         kfree(key);
 626
 627 error:
 628         return err;
 629 }
 630
 631 static int esp_init_state(struct xfrm_state *x)
 632 {
 633         struct esp_data *esp;
 634         struct crypto_aead *aead;
 635         u32 align;
 636         int err;
 637
 638         esp = kzalloc(sizeof(*esp), GFP_KERNEL);
 639         if (esp == NULL)
 640                 return -ENOMEM;
 641
 642         x->data = esp;
 643
 644         if (x->aead)
 645                 err = esp_init_aead(x);
 646         else
 647                 err = esp_init_authenc(x);
 648
 649         if (err)
 650                 goto error;
 651
 652         aead = esp->aead;
 653
 654         esp->padlen = 0;
 655
 656         x->props.header_len = sizeof(struct ip_esp_hdr) +
 657                               crypto_aead_ivsize(aead);
 658         if (x->props.mode == XFRM_MODE_TUNNEL)
 659                 x->props.header_len += sizeof(struct iphdr);
 660         else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
 661                 x->props.header_len += IPV4_BEET_PHMAXLEN;
 662         if (x->encap) {
 663                 struct xfrm_encap_tmpl *encap = x->encap;
 664
 665                 switch (encap->encap_type) {
 666                 default:
 667                         goto error;
 668                 case UDP_ENCAP_ESPINUDP:
 669                         x->props.header_len += sizeof(struct udphdr);
 670                         break;
 671                 case UDP_ENCAP_ESPINUDP_NON_IKE:
 672                         x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
 673                         break;
 674                 }
 675         }
 676
 677         align = ALIGN(crypto_aead_blocksize(aead), 4);
 678         if (esp->padlen)
 679                 align = max_t(u32, align, esp->padlen);
 680         x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
 681
 682 error:
 683         return err;
 684 }
 685
 686 static const struct xfrm_type esp_type =
 687 {
 688         .description    = "ESP4",
 689         .owner          = THIS_MODULE,
 690         .proto          = IPPROTO_ESP,
 691         .flags          = XFRM_TYPE_REPLAY_PROT,
 692         .init_state     = esp_init_state,
 693         .destructor     = esp_destroy,
 694         .get_mtu        = esp4_get_mtu,
 695         .input          = esp_input,
 696         .output         = esp_output
 697 };
 698
 699 static const struct net_protocol esp4_protocol = {
 700         .handler        =       xfrm4_rcv,
 701         .err_handler    =       esp4_err,
 702         .no_policy      =       1,
 703         .netns_ok       =       1,
 704 };
 705
 706 static int __init esp4_init(void)
 707 {
 708         if (xfrm_register_type(&esp_type, AF_INET) < 0) {
 709                 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
 710                 return -EAGAIN;
 711         }
 712         if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
 713                 printk(KERN_INFO "ip esp init: can't add protocol\n");
 714                 xfrm_unregister_type(&esp_type, AF_INET);
 715                 return -EAGAIN;
 716         }
 717         return 0;
 718 }
 719
 720 static void __exit esp4_fini(void)
 721 {
 722         if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
 723                 printk(KERN_INFO "ip esp close: can't remove protocol\n");
 724         if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
 725                 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
 726 }
 727
 728 module_init(esp4_init);
 729 module_exit(esp4_fini);
 730 MODULE_LICENSE("GPL");
 731 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);