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
21struct 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
28static 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 */
38static 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
60static inline __be32 *esp_tmp_seqhi(void *tmp)
61{
62	return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
63}
64static 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
71static 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
82static 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
92static 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
100static 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
108static 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
116static 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			      ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
261
262	ESP_SKB_CB(skb)->tmp = tmp;
263	err = crypto_aead_givencrypt(req);
264	if (err == -EINPROGRESS)
265		goto error;
266
267	if (err == -EBUSY)
268		err = NET_XMIT_DROP;
269
270	kfree(tmp);
271
272error:
273	return err;
274}
275
276static int esp_input_done2(struct sk_buff *skb, int err)
277{
278	const struct iphdr *iph;
279	struct xfrm_state *x = xfrm_input_state(skb);
280	struct crypto_aead *aead = x->data;
281	int alen = crypto_aead_authsize(aead);
282	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
283	int elen = skb->len - hlen;
284	int ihl;
285	u8 nexthdr[2];
286	int padlen;
287
288	kfree(ESP_SKB_CB(skb)->tmp);
289
290	if (unlikely(err))
291		goto out;
292
293	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
294		BUG();
295
296	err = -EINVAL;
297	padlen = nexthdr[0];
298	if (padlen + 2 + alen >= elen)
299		goto out;
300
301	/* ... check padding bits here. Silly. :-) */
302
303	iph = ip_hdr(skb);
304	ihl = iph->ihl * 4;
305
306	if (x->encap) {
307		struct xfrm_encap_tmpl *encap = x->encap;
308		struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
309
310		/*
311		 * 1) if the NAT-T peer's IP or port changed then
312		 *    advertize the change to the keying daemon.
313		 *    This is an inbound SA, so just compare
314		 *    SRC ports.
315		 */
316		if (iph->saddr != x->props.saddr.a4 ||
317		    uh->source != encap->encap_sport) {
318			xfrm_address_t ipaddr;
319
320			ipaddr.a4 = iph->saddr;
321			km_new_mapping(x, &ipaddr, uh->source);
322
323			/* XXX: perhaps add an extra
324			 * policy check here, to see
325			 * if we should allow or
326			 * reject a packet from a
327			 * different source
328			 * address/port.
329			 */
330		}
331
332		/*
333		 * 2) ignore UDP/TCP checksums in case
334		 *    of NAT-T in Transport Mode, or
335		 *    perform other post-processing fixes
336		 *    as per draft-ietf-ipsec-udp-encaps-06,
337		 *    section 3.1.2
338		 */
339		if (x->props.mode == XFRM_MODE_TRANSPORT)
340			skb->ip_summed = CHECKSUM_UNNECESSARY;
341	}
342
343	pskb_trim(skb, skb->len - alen - padlen - 2);
344	__skb_pull(skb, hlen);
345	if (x->props.mode == XFRM_MODE_TUNNEL)
346		skb_reset_transport_header(skb);
347	else
348		skb_set_transport_header(skb, -ihl);
349
350	err = nexthdr[1];
351
352	/* RFC4303: Drop dummy packets without any error */
353	if (err == IPPROTO_NONE)
354		err = -EINVAL;
355
356out:
357	return err;
358}
359
360static void esp_input_done(struct crypto_async_request *base, int err)
361{
362	struct sk_buff *skb = base->data;
363
364	xfrm_input_resume(skb, esp_input_done2(skb, err));
365}
366
367/*
368 * Note: detecting truncated vs. non-truncated authentication data is very
369 * expensive, so we only support truncated data, which is the recommended
370 * and common case.
371 */
372static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
373{
374	struct ip_esp_hdr *esph;
375	struct crypto_aead *aead = x->data;
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	err = skb_cow_data(skb, 0, &trailer);
397	if (err < 0)
398		goto out;
399
400	nfrags = err;
401
402	assoclen = sizeof(*esph);
403	sglists = 1;
404	seqhilen = 0;
405
406	if (x->props.flags & XFRM_STATE_ESN) {
407		sglists += 2;
408		seqhilen += sizeof(__be32);
409		assoclen += seqhilen;
410	}
411
412	err = -ENOMEM;
413	tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
414	if (!tmp)
415		goto out;
416
417	ESP_SKB_CB(skb)->tmp = tmp;
418	seqhi = esp_tmp_seqhi(tmp);
419	iv = esp_tmp_iv(aead, tmp, seqhilen);
420	req = esp_tmp_req(aead, iv);
421	asg = esp_req_sg(aead, req);
422	sg = asg + sglists;
423
424	skb->ip_summed = CHECKSUM_NONE;
425
426	esph = (struct ip_esp_hdr *)skb->data;
427
428	/* Get ivec. This can be wrong, check against another impls. */
429	iv = esph->enc_data;
430
431	sg_init_table(sg, nfrags);
432	skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
433
434	if ((x->props.flags & XFRM_STATE_ESN)) {
435		sg_init_table(asg, 3);
436		sg_set_buf(asg, &esph->spi, sizeof(__be32));
437		*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
438		sg_set_buf(asg + 1, seqhi, seqhilen);
439		sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
440	} else
441		sg_init_one(asg, esph, sizeof(*esph));
442
443	aead_request_set_callback(req, 0, esp_input_done, skb);
444	aead_request_set_crypt(req, sg, sg, elen, iv);
445	aead_request_set_assoc(req, asg, assoclen);
446
447	err = crypto_aead_decrypt(req);
448	if (err == -EINPROGRESS)
449		goto out;
450
451	err = esp_input_done2(skb, err);
452
453out:
454	return err;
455}
456
457static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
458{
459	struct crypto_aead *aead = x->data;
460	u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
461	unsigned int net_adj;
462
463	switch (x->props.mode) {
464	case XFRM_MODE_TRANSPORT:
465	case XFRM_MODE_BEET:
466		net_adj = sizeof(struct iphdr);
467		break;
468	case XFRM_MODE_TUNNEL:
469		net_adj = 0;
470		break;
471	default:
472		BUG();
473	}
474
475	return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
476		 net_adj) & ~(blksize - 1)) + net_adj - 2;
477}
478
479static int esp4_err(struct sk_buff *skb, u32 info)
480{
481	struct net *net = dev_net(skb->dev);
482	const struct iphdr *iph = (const struct iphdr *)skb->data;
483	struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
484	struct xfrm_state *x;
485
486	switch (icmp_hdr(skb)->type) {
487	case ICMP_DEST_UNREACH:
488		if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
489			return 0;
490	case ICMP_REDIRECT:
491		break;
492	default:
493		return 0;
494	}
495
496	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
497			      esph->spi, IPPROTO_ESP, AF_INET);
498	if (!x)
499		return 0;
500
501	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
502		ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
503	else
504		ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
505	xfrm_state_put(x);
506
507	return 0;
508}
509
510static void esp_destroy(struct xfrm_state *x)
511{
512	struct crypto_aead *aead = x->data;
513
514	if (!aead)
515		return;
516
517	crypto_free_aead(aead);
518}
519
520static int esp_init_aead(struct xfrm_state *x)
521{
522	struct crypto_aead *aead;
523	int err;
524
525	aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
526	err = PTR_ERR(aead);
527	if (IS_ERR(aead))
528		goto error;
529
530	x->data = aead;
531
532	err = crypto_aead_setkey(aead, x->aead->alg_key,
533				 (x->aead->alg_key_len + 7) / 8);
534	if (err)
535		goto error;
536
537	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
538	if (err)
539		goto error;
540
541error:
542	return err;
543}
544
545static int esp_init_authenc(struct xfrm_state *x)
546{
547	struct crypto_aead *aead;
548	struct crypto_authenc_key_param *param;
549	struct rtattr *rta;
550	char *key;
551	char *p;
552	char authenc_name[CRYPTO_MAX_ALG_NAME];
553	unsigned int keylen;
554	int err;
555
556	err = -EINVAL;
557	if (!x->ealg)
558		goto error;
559
560	err = -ENAMETOOLONG;
561
562	if ((x->props.flags & XFRM_STATE_ESN)) {
563		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
564			     "authencesn(%s,%s)",
565			     x->aalg ? x->aalg->alg_name : "digest_null",
566			     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
567			goto error;
568	} else {
569		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
570			     "authenc(%s,%s)",
571			     x->aalg ? x->aalg->alg_name : "digest_null",
572			     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
573			goto error;
574	}
575
576	aead = crypto_alloc_aead(authenc_name, 0, 0);
577	err = PTR_ERR(aead);
578	if (IS_ERR(aead))
579		goto error;
580
581	x->data = aead;
582
583	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
584		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
585	err = -ENOMEM;
586	key = kmalloc(keylen, GFP_KERNEL);
587	if (!key)
588		goto error;
589
590	p = key;
591	rta = (void *)p;
592	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
593	rta->rta_len = RTA_LENGTH(sizeof(*param));
594	param = RTA_DATA(rta);
595	p += RTA_SPACE(sizeof(*param));
596
597	if (x->aalg) {
598		struct xfrm_algo_desc *aalg_desc;
599
600		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
601		p += (x->aalg->alg_key_len + 7) / 8;
602
603		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
604		BUG_ON(!aalg_desc);
605
606		err = -EINVAL;
607		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
608		    crypto_aead_authsize(aead)) {
609			pr_info("ESP: %s digestsize %u != %hu\n",
610				x->aalg->alg_name,
611				crypto_aead_authsize(aead),
612				aalg_desc->uinfo.auth.icv_fullbits / 8);
613			goto free_key;
614		}
615
616		err = crypto_aead_setauthsize(
617			aead, x->aalg->alg_trunc_len / 8);
618		if (err)
619			goto free_key;
620	}
621
622	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
623	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
624
625	err = crypto_aead_setkey(aead, key, keylen);
626
627free_key:
628	kfree(key);
629
630error:
631	return err;
632}
633
634static int esp_init_state(struct xfrm_state *x)
635{
636	struct crypto_aead *aead;
637	u32 align;
638	int err;
639
640	x->data = NULL;
641
642	if (x->aead)
643		err = esp_init_aead(x);
644	else
645		err = esp_init_authenc(x);
646
647	if (err)
648		goto error;
649
650	aead = x->data;
651
652	x->props.header_len = sizeof(struct ip_esp_hdr) +
653			      crypto_aead_ivsize(aead);
654	if (x->props.mode == XFRM_MODE_TUNNEL)
655		x->props.header_len += sizeof(struct iphdr);
656	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
657		x->props.header_len += IPV4_BEET_PHMAXLEN;
658	if (x->encap) {
659		struct xfrm_encap_tmpl *encap = x->encap;
660
661		switch (encap->encap_type) {
662		default:
663			goto error;
664		case UDP_ENCAP_ESPINUDP:
665			x->props.header_len += sizeof(struct udphdr);
666			break;
667		case UDP_ENCAP_ESPINUDP_NON_IKE:
668			x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
669			break;
670		}
671	}
672
673	align = ALIGN(crypto_aead_blocksize(aead), 4);
674	x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
675
676error:
677	return err;
678}
679
680static int esp4_rcv_cb(struct sk_buff *skb, int err)
681{
682	return 0;
683}
684
685static 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
698static struct xfrm4_protocol esp4_protocol = {
699	.handler	=	xfrm4_rcv,
700	.input_handler	=	xfrm_input,
701	.cb_handler	=	esp4_rcv_cb,
702	.err_handler	=	esp4_err,
703	.priority	=	0,
704};
705
706static int __init esp4_init(void)
707{
708	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
709		pr_info("%s: can't add xfrm type\n", __func__);
710		return -EAGAIN;
711	}
712	if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
713		pr_info("%s: can't add protocol\n", __func__);
714		xfrm_unregister_type(&esp_type, AF_INET);
715		return -EAGAIN;
716	}
717	return 0;
718}
719
720static void __exit esp4_fini(void)
721{
722	if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
723		pr_info("%s: can't remove protocol\n", __func__);
724	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
725		pr_info("%s: can't remove xfrm type\n", __func__);
726}
727
728module_init(esp4_init);
729module_exit(esp4_fini);
730MODULE_LICENSE("GPL");
731MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
732