xref: /openbmc/linux/net/ipv4/esp4.c (revision 565d76cb)
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 	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 	struct iphdr *iph = (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, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
496 	if (!x)
497 		return;
498 	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
499 		 ntohl(esph->spi), ntohl(iph->daddr));
500 	xfrm_state_put(x);
501 }
502 
503 static void esp_destroy(struct xfrm_state *x)
504 {
505 	struct esp_data *esp = x->data;
506 
507 	if (!esp)
508 		return;
509 
510 	crypto_free_aead(esp->aead);
511 	kfree(esp);
512 }
513 
514 static int esp_init_aead(struct xfrm_state *x)
515 {
516 	struct esp_data *esp = x->data;
517 	struct crypto_aead *aead;
518 	int err;
519 
520 	aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
521 	err = PTR_ERR(aead);
522 	if (IS_ERR(aead))
523 		goto error;
524 
525 	esp->aead = aead;
526 
527 	err = crypto_aead_setkey(aead, x->aead->alg_key,
528 				 (x->aead->alg_key_len + 7) / 8);
529 	if (err)
530 		goto error;
531 
532 	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
533 	if (err)
534 		goto error;
535 
536 error:
537 	return err;
538 }
539 
540 static int esp_init_authenc(struct xfrm_state *x)
541 {
542 	struct esp_data *esp = x->data;
543 	struct crypto_aead *aead;
544 	struct crypto_authenc_key_param *param;
545 	struct rtattr *rta;
546 	char *key;
547 	char *p;
548 	char authenc_name[CRYPTO_MAX_ALG_NAME];
549 	unsigned int keylen;
550 	int err;
551 
552 	err = -EINVAL;
553 	if (x->ealg == NULL)
554 		goto error;
555 
556 	err = -ENAMETOOLONG;
557 
558 	if ((x->props.flags & XFRM_STATE_ESN)) {
559 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
560 			     "authencesn(%s,%s)",
561 			     x->aalg ? x->aalg->alg_name : "digest_null",
562 			     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
563 			goto error;
564 	} else {
565 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
566 			     "authenc(%s,%s)",
567 			     x->aalg ? x->aalg->alg_name : "digest_null",
568 			     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
569 			goto error;
570 	}
571 
572 	aead = crypto_alloc_aead(authenc_name, 0, 0);
573 	err = PTR_ERR(aead);
574 	if (IS_ERR(aead))
575 		goto error;
576 
577 	esp->aead = aead;
578 
579 	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
580 		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
581 	err = -ENOMEM;
582 	key = kmalloc(keylen, GFP_KERNEL);
583 	if (!key)
584 		goto error;
585 
586 	p = key;
587 	rta = (void *)p;
588 	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
589 	rta->rta_len = RTA_LENGTH(sizeof(*param));
590 	param = RTA_DATA(rta);
591 	p += RTA_SPACE(sizeof(*param));
592 
593 	if (x->aalg) {
594 		struct xfrm_algo_desc *aalg_desc;
595 
596 		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
597 		p += (x->aalg->alg_key_len + 7) / 8;
598 
599 		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
600 		BUG_ON(!aalg_desc);
601 
602 		err = -EINVAL;
603 		if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
604 		    crypto_aead_authsize(aead)) {
605 			NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
606 				 x->aalg->alg_name,
607 				 crypto_aead_authsize(aead),
608 				 aalg_desc->uinfo.auth.icv_fullbits/8);
609 			goto free_key;
610 		}
611 
612 		err = crypto_aead_setauthsize(
613 			aead, x->aalg->alg_trunc_len / 8);
614 		if (err)
615 			goto free_key;
616 	}
617 
618 	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
619 	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
620 
621 	err = crypto_aead_setkey(aead, key, keylen);
622 
623 free_key:
624 	kfree(key);
625 
626 error:
627 	return err;
628 }
629 
630 static int esp_init_state(struct xfrm_state *x)
631 {
632 	struct esp_data *esp;
633 	struct crypto_aead *aead;
634 	u32 align;
635 	int err;
636 
637 	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
638 	if (esp == NULL)
639 		return -ENOMEM;
640 
641 	x->data = esp;
642 
643 	if (x->aead)
644 		err = esp_init_aead(x);
645 	else
646 		err = esp_init_authenc(x);
647 
648 	if (err)
649 		goto error;
650 
651 	aead = esp->aead;
652 
653 	esp->padlen = 0;
654 
655 	x->props.header_len = sizeof(struct ip_esp_hdr) +
656 			      crypto_aead_ivsize(aead);
657 	if (x->props.mode == XFRM_MODE_TUNNEL)
658 		x->props.header_len += sizeof(struct iphdr);
659 	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
660 		x->props.header_len += IPV4_BEET_PHMAXLEN;
661 	if (x->encap) {
662 		struct xfrm_encap_tmpl *encap = x->encap;
663 
664 		switch (encap->encap_type) {
665 		default:
666 			goto error;
667 		case UDP_ENCAP_ESPINUDP:
668 			x->props.header_len += sizeof(struct udphdr);
669 			break;
670 		case UDP_ENCAP_ESPINUDP_NON_IKE:
671 			x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
672 			break;
673 		}
674 	}
675 
676 	align = ALIGN(crypto_aead_blocksize(aead), 4);
677 	if (esp->padlen)
678 		align = max_t(u32, align, esp->padlen);
679 	x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
680 
681 error:
682 	return err;
683 }
684 
685 static const struct xfrm_type esp_type =
686 {
687 	.description	= "ESP4",
688 	.owner		= THIS_MODULE,
689 	.proto	     	= IPPROTO_ESP,
690 	.flags		= XFRM_TYPE_REPLAY_PROT,
691 	.init_state	= esp_init_state,
692 	.destructor	= esp_destroy,
693 	.get_mtu	= esp4_get_mtu,
694 	.input		= esp_input,
695 	.output		= esp_output
696 };
697 
698 static const struct net_protocol esp4_protocol = {
699 	.handler	=	xfrm4_rcv,
700 	.err_handler	=	esp4_err,
701 	.no_policy	=	1,
702 	.netns_ok	=	1,
703 };
704 
705 static int __init esp4_init(void)
706 {
707 	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
708 		printk(KERN_INFO "ip esp init: can't add xfrm type\n");
709 		return -EAGAIN;
710 	}
711 	if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
712 		printk(KERN_INFO "ip esp init: can't add protocol\n");
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 (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
722 		printk(KERN_INFO "ip esp close: can't remove protocol\n");
723 	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
724 		printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
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);
731