[deliverable/linux.git] / net / ipv4 / ah4.c

#include <linux/err.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/ah.h>
#include <linux/crypto.h>
#include <linux/pfkeyv2.h>
#include <linux/spinlock.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <asm/scatterlist.h>


/* Clear mutable options and find final destination to substitute
 * into IP header for icv calculation. Options are already checked
 * for validity, so paranoia is not required. */

static int ip_clear_mutable_options(struct iphdr *iph, __be32 *daddr)
{
	unsigned char * optptr = (unsigned char*)(iph+1);
	int  l = iph->ihl*4 - sizeof(struct iphdr);
	int  optlen;

	while (l > 0) {
		switch (*optptr) {
		case IPOPT_END:
			return 0;
		case IPOPT_NOOP:
			l--;
			optptr++;
			continue;
		}
		optlen = optptr[1];
		if (optlen<2 || optlen>l)
			return -EINVAL;
		switch (*optptr) {
		case IPOPT_SEC:
		case 0x85:	/* Some "Extended Security" crap. */
		case IPOPT_CIPSO:
		case IPOPT_RA:
		case 0x80|21:	/* RFC1770 */
			break;
		case IPOPT_LSRR:
		case IPOPT_SSRR:
			if (optlen < 6)
				return -EINVAL;
			memcpy(daddr, optptr+optlen-4, 4);
			/* Fall through */
		default:
			memset(optptr, 0, optlen);
		}
		l -= optlen;
		optptr += optlen;
	}
	return 0;
}

static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	struct iphdr *iph, *top_iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	union {
		struct iphdr	iph;
		char 		buf[60];
	} tmp_iph;

	skb_push(skb, -skb_network_offset(skb));
	top_iph = ip_hdr(skb);
	iph = &tmp_iph.iph;

	iph->tos = top_iph->tos;
	iph->ttl = top_iph->ttl;
	iph->frag_off = top_iph->frag_off;

	if (top_iph->ihl != 5) {
		iph->daddr = top_iph->daddr;
		memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
		err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
		if (err)
			goto error;
	}

	ah = (struct ip_auth_hdr *)((char *)top_iph+top_iph->ihl*4);
	ah->nexthdr = top_iph->protocol;

	top_iph->tos = 0;
	top_iph->tot_len = htons(skb->len);
	top_iph->frag_off = 0;
	top_iph->ttl = 0;
	top_iph->protocol = IPPROTO_AH;
	top_iph->check = 0;

	ahp = x->data;
	ah->hdrlen  = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
				   ahp->icv_trunc_len) >> 2) - 2;

	ah->reserved = 0;
	ah->spi = x->id.spi;
	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);

	spin_lock_bh(&x->lock);
	err = ah_mac_digest(ahp, skb, ah->auth_data);
	memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
	spin_unlock_bh(&x->lock);

	if (err)
		goto error;

	top_iph->tos = iph->tos;
	top_iph->ttl = iph->ttl;
	top_iph->frag_off = iph->frag_off;
	if (top_iph->ihl != 5) {
		top_iph->daddr = iph->daddr;
		memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	}

	ip_send_check(top_iph);

	err = 0;

error:
	return err;
}

static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int ah_hlen;
	int ihl;
	int err = -EINVAL;
	struct iphdr *iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	char work_buf[60];

	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
		goto out;

	ah = (struct ip_auth_hdr*)skb->data;
	ahp = x->data;
	ah_hlen = (ah->hdrlen + 2) << 2;

	if (ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_full_len) &&
	    ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len))
		goto out;

	if (!pskb_may_pull(skb, ah_hlen))
		goto out;

	/* We are going to _remove_ AH header to keep sockets happy,
	 * so... Later this can change. */
	if (skb_cloned(skb) &&
	    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
		goto out;

	skb->ip_summed = CHECKSUM_NONE;

	ah = (struct ip_auth_hdr*)skb->data;
	iph = ip_hdr(skb);

	ihl = skb->data - skb_network_header(skb);
	memcpy(work_buf, iph, ihl);

	iph->ttl = 0;
	iph->tos = 0;
	iph->frag_off = 0;
	iph->check = 0;
	if (ihl > sizeof(*iph)) {
		__be32 dummy;
		if (ip_clear_mutable_options(iph, &dummy))
			goto out;
	}
	{
		u8 auth_data[MAX_AH_AUTH_LEN];

		memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
		skb_push(skb, ihl);
		err = ah_mac_digest(ahp, skb, ah->auth_data);
		if (err)
			goto out;
		err = -EINVAL;
		if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
			x->stats.integrity_failed++;
			goto out;
		}
	}
	((struct iphdr*)work_buf)->protocol = ah->nexthdr;
	skb->network_header += ah_hlen;
	memcpy(skb_network_header(skb), work_buf, ihl);
	skb->transport_header = skb->network_header;
	__skb_pull(skb, ah_hlen + ihl);

	return 0;

out:
	return err;
}

static void ah4_err(struct sk_buff *skb, u32 info)
{
	struct iphdr *iph = (struct iphdr*)skb->data;
	struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
	    icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
		return;

	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
	if (!x)
		return;
	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
	       ntohl(ah->spi), ntohl(iph->daddr));
	xfrm_state_put(x);
}

static int ah_init_state(struct xfrm_state *x)
{
	struct ah_data *ahp = NULL;
	struct xfrm_algo_desc *aalg_desc;
	struct crypto_hash *tfm;

	if (!x->aalg)
		goto error;

	if (x->encap)
		goto error;

	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
	if (ahp == NULL)
		return -ENOMEM;

	tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(tfm))
		goto error;

	ahp->tfm = tfm;
	if (crypto_hash_setkey(tfm, x->aalg->alg_key,
			       (x->aalg->alg_key_len + 7) / 8))
		goto error;

	/*
	 * Lookup the algorithm description maintained by xfrm_algo,
	 * verify crypto transform properties, and store information
	 * we need for AH processing.  This lookup cannot fail here
	 * after a successful crypto_alloc_hash().
	 */
	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	BUG_ON(!aalg_desc);

	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
	    crypto_hash_digestsize(tfm)) {
		printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
		       x->aalg->alg_name, crypto_hash_digestsize(tfm),
		       aalg_desc->uinfo.auth.icv_fullbits/8);
		goto error;
	}

	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;

	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);

	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	if (!ahp->work_icv)
		goto error;

	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
	if (x->props.mode == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct iphdr);
	x->data = ahp;

	return 0;

error:
	if (ahp) {
		kfree(ahp->work_icv);
		crypto_free_hash(ahp->tfm);
		kfree(ahp);
	}
	return -EINVAL;
}

static void ah_destroy(struct xfrm_state *x)
{
	struct ah_data *ahp = x->data;

	if (!ahp)
		return;

	kfree(ahp->work_icv);
	ahp->work_icv = NULL;
	crypto_free_hash(ahp->tfm);
	ahp->tfm = NULL;
	kfree(ahp);
}


static struct xfrm_type ah_type =
{
	.description	= "AH4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_AH,
	.flags		= XFRM_TYPE_REPLAY_PROT,
	.init_state	= ah_init_state,
	.destructor	= ah_destroy,
	.input		= ah_input,
	.output		= ah_output
};

static struct net_protocol ah4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	ah4_err,
	.no_policy	=	1,
};

static int __init ah4_init(void)
{
	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
		printk(KERN_INFO "ip ah init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
		printk(KERN_INFO "ip ah init: can't add protocol\n");
		xfrm_unregister_type(&ah_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ah4_fini(void)
{
	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
		printk(KERN_INFO "ip ah close: can't remove protocol\n");
	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
		printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
}

module_init(ah4_init);
module_exit(ah4_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);
Commit	Line	Data
07d4ee58	1	#include <linux/err.h>
1da177e4 LT	2	#include <linux/module.h>
	3	#include <net/ip.h>
	4	#include <net/xfrm.h>
	5	#include <net/ah.h>
	6	#include <linux/crypto.h>
	7	#include <linux/pfkeyv2.h>
b7c6538c	8	#include <linux/spinlock.h>
1da177e4	9	#include <net/icmp.h>
14c85021	10	#include <net/protocol.h>
1da177e4 LT	11	#include <asm/scatterlist.h>
	12
	13
	14	/* Clear mutable options and find final destination to substitute
	15	* into IP header for icv calculation. Options are already checked
	16	* for validity, so paranoia is not required. */
	17
d5a0a1e3	18	static int ip_clear_mutable_options(struct iphdr iph, __be32 daddr)
1da177e4 LT	19	{
	20	unsigned char * optptr = (unsigned char*)(iph+1);
	21	int l = iph->ihl*4 - sizeof(struct iphdr);
	22	int optlen;
	23
	24	while (l > 0) {
	25	switch (*optptr) {
	26	case IPOPT_END:
	27	return 0;
	28	case IPOPT_NOOP:
	29	l--;
	30	optptr++;
	31	continue;
	32	}
	33	optlen = optptr[1];
	34	if (optlen<2 \|\| optlen>l)
	35	return -EINVAL;
	36	switch (*optptr) {
	37	case IPOPT_SEC:
	38	case 0x85: /* Some "Extended Security" crap. */
11a03f78	39	case IPOPT_CIPSO:
1da177e4 LT	40	case IPOPT_RA:
	41	case 0x80\|21: /* RFC1770 */
	42	break;
	43	case IPOPT_LSRR:
	44	case IPOPT_SSRR:
	45	if (optlen < 6)
	46	return -EINVAL;
	47	memcpy(daddr, optptr+optlen-4, 4);
	48	/* Fall through */
	49	default:
96fe1c02	50	memset(optptr, 0, optlen);
1da177e4 LT	51	}
	52	l -= optlen;
	53	optptr += optlen;
	54	}
	55	return 0;
	56	}
	57
	58	static int ah_output(struct xfrm_state x, struct sk_buff skb)
	59	{
	60	int err;
	61	struct iphdr iph, top_iph;
	62	struct ip_auth_hdr *ah;
	63	struct ah_data *ahp;
	64	union {
	65	struct iphdr iph;
	66	char buf[60];
	67	} tmp_iph;
	68
7b277b1a	69	skb_push(skb, -skb_network_offset(skb));
eddc9ec5	70	top_iph = ip_hdr(skb);
1da177e4 LT	71	iph = &tmp_iph.iph;
	72
	73	iph->tos = top_iph->tos;
	74	iph->ttl = top_iph->ttl;
	75	iph->frag_off = top_iph->frag_off;
	76
	77	if (top_iph->ihl != 5) {
	78	iph->daddr = top_iph->daddr;
	79	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	80	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	81	if (err)
	82	goto error;
	83	}
	84
	85	ah = (struct ip_auth_hdr )((char )top_iph+top_iph->ihl*4);
	86	ah->nexthdr = top_iph->protocol;
	87
	88	top_iph->tos = 0;
	89	top_iph->tot_len = htons(skb->len);
	90	top_iph->frag_off = 0;
	91	top_iph->ttl = 0;
	92	top_iph->protocol = IPPROTO_AH;
	93	top_iph->check = 0;
	94
	95	ahp = x->data;
e905a9ed	96	ah->hdrlen = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
1da177e4 LT	97	ahp->icv_trunc_len) >> 2) - 2;
	98
	99	ah->reserved = 0;
	100	ah->spi = x->id.spi;
436a0a40	101	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
b7c6538c HX	102
b7c6538c HX	103	spin_lock_bh(&x->lock);
07d4ee58	104	err = ah_mac_digest(ahp, skb, ah->auth_data);
b7c6538c HX	105	memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
	106	spin_unlock_bh(&x->lock);
	107
07d4ee58 HX	108	if (err)
07d4ee58 HX	109	goto error;
1da177e4 LT	110
	111	top_iph->tos = iph->tos;
	112	top_iph->ttl = iph->ttl;
	113	top_iph->frag_off = iph->frag_off;
	114	if (top_iph->ihl != 5) {
	115	top_iph->daddr = iph->daddr;
	116	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	117	}
	118
	119	ip_send_check(top_iph);
	120
	121	err = 0;
	122
	123	error:
	124	return err;
	125	}
	126
e695633e	127	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	128	{
1da177e4 LT	129	int ah_hlen;
31a4ab93	130	int ihl;
07d4ee58	131	int err = -EINVAL;
1da177e4 LT	132	struct iphdr *iph;
	133	struct ip_auth_hdr *ah;
	134	struct ah_data *ahp;
	135	char work_buf[60];
	136
	137	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
	138	goto out;
	139
	140	ah = (struct ip_auth_hdr*)skb->data;
	141	ahp = x->data;
	142	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	143
1da177e4	144	if (ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_full_len) &&
e905a9ed	145	ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len))
1da177e4 LT	146	goto out;
	147
	148	if (!pskb_may_pull(skb, ah_hlen))
	149	goto out;
	150
	151	/* We are going to _remove_ AH header to keep sockets happy,
	152	* so... Later this can change. */
	153	if (skb_cloned(skb) &&
	154	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	155	goto out;
	156
	157	skb->ip_summed = CHECKSUM_NONE;
	158
	159	ah = (struct ip_auth_hdr*)skb->data;
eddc9ec5	160	iph = ip_hdr(skb);
1da177e4	161
d56f90a7	162	ihl = skb->data - skb_network_header(skb);
31a4ab93	163	memcpy(work_buf, iph, ihl);
1da177e4 LT	164
	165	iph->ttl = 0;
	166	iph->tos = 0;
	167	iph->frag_off = 0;
	168	iph->check = 0;
31a4ab93	169	if (ihl > sizeof(*iph)) {
d5a0a1e3	170	__be32 dummy;
1da177e4 LT	171	if (ip_clear_mutable_options(iph, &dummy))
	172	goto out;
	173	}
e905a9ed	174	{
1da177e4	175	u8 auth_data[MAX_AH_AUTH_LEN];
e905a9ed	176
1da177e4	177	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
31a4ab93	178	skb_push(skb, ihl);
07d4ee58 HX	179	err = ah_mac_digest(ahp, skb, ah->auth_data);
	180	if (err)
	181	goto out;
	182	err = -EINVAL;
	183	if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
1da177e4 LT	184	x->stats.integrity_failed++;
	185	goto out;
	186	}
	187	}
	188	((struct iphdr*)work_buf)->protocol = ah->nexthdr;
b0e380b1	189	skb->network_header += ah_hlen;
badff6d0	190	memcpy(skb_network_header(skb), work_buf, ihl);
b0e380b1	191	skb->transport_header = skb->network_header;
31a4ab93	192	__skb_pull(skb, ah_hlen + ihl);
1da177e4 LT	193
	194	return 0;
	195
	196	out:
07d4ee58	197	return err;
1da177e4 LT	198	}
	199
	200	static void ah4_err(struct sk_buff *skb, u32 info)
	201	{
	202	struct iphdr iph = (struct iphdr)skb->data;
	203	struct ip_auth_hdr ah = (struct ip_auth_hdr)(skb->data+(iph->ihl<<2));
	204	struct xfrm_state *x;
	205
88c7664f ACM	206	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	207	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	208	return;
	209
	210	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
	211	if (!x)
	212	return;
	213	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
	214	ntohl(ah->spi), ntohl(iph->daddr));
	215	xfrm_state_put(x);
	216	}
	217
72cb6962	218	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	219	{
	220	struct ah_data *ahp = NULL;
	221	struct xfrm_algo_desc *aalg_desc;
07d4ee58	222	struct crypto_hash *tfm;
1da177e4 LT	223
	224	if (!x->aalg)
	225	goto error;
	226
1da177e4 LT	227	if (x->encap)
	228	goto error;
	229
0da974f4	230	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
1da177e4 LT	231	if (ahp == NULL)
	232	return -ENOMEM;
	233
07d4ee58 HX	234	tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
	235	if (IS_ERR(tfm))
	236	goto error;
	237
	238	ahp->tfm = tfm;
bc31d3b2 HX	239	if (crypto_hash_setkey(tfm, x->aalg->alg_key,
bc31d3b2 HX	240	(x->aalg->alg_key_len + 7) / 8))
1da177e4	241	goto error;
e905a9ed	242
1da177e4 LT	243	/*
	244	* Lookup the algorithm description maintained by xfrm_algo,
	245	* verify crypto transform properties, and store information
	246	* we need for AH processing. This lookup cannot fail here
07d4ee58	247	* after a successful crypto_alloc_hash().
1da177e4 LT	248	*/
	249	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	250	BUG_ON(!aalg_desc);
	251
	252	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58	253	crypto_hash_digestsize(tfm)) {
1da177e4	254	printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
07d4ee58	255	x->aalg->alg_name, crypto_hash_digestsize(tfm),
1da177e4 LT	256	aalg_desc->uinfo.auth.icv_fullbits/8);
	257	goto error;
	258	}
e905a9ed	259
1da177e4 LT	260	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
1da177e4 LT	261	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
e905a9ed	262
1da177e4	263	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
e905a9ed	264
1da177e4 LT	265	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	266	if (!ahp->work_icv)
	267	goto error;
e905a9ed	268
1da177e4	269	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
7e49e6de	270	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	271	x->props.header_len += sizeof(struct iphdr);
	272	x->data = ahp;
	273
	274	return 0;
	275
	276	error:
	277	if (ahp) {
573dbd95	278	kfree(ahp->work_icv);
07d4ee58	279	crypto_free_hash(ahp->tfm);
1da177e4 LT	280	kfree(ahp);
	281	}
	282	return -EINVAL;
	283	}
	284
	285	static void ah_destroy(struct xfrm_state *x)
	286	{
	287	struct ah_data *ahp = x->data;
	288
	289	if (!ahp)
	290	return;
	291
573dbd95 JJ	292	kfree(ahp->work_icv);
573dbd95 JJ	293	ahp->work_icv = NULL;
07d4ee58	294	crypto_free_hash(ahp->tfm);
573dbd95	295	ahp->tfm = NULL;
1da177e4 LT	296	kfree(ahp);
	297	}
	298
	299
	300	static struct xfrm_type ah_type =
	301	{
	302	.description = "AH4",
	303	.owner = THIS_MODULE,
	304	.proto = IPPROTO_AH,
436a0a40	305	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	306	.init_state = ah_init_state,
	307	.destructor = ah_destroy,
	308	.input = ah_input,
	309	.output = ah_output
	310	};
	311
	312	static struct net_protocol ah4_protocol = {
	313	.handler = xfrm4_rcv,
	314	.err_handler = ah4_err,
	315	.no_policy = 1,
	316	};
	317
	318	static int __init ah4_init(void)
	319	{
	320	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
	321	printk(KERN_INFO "ip ah init: can't add xfrm type\n");
	322	return -EAGAIN;
	323	}
	324	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
	325	printk(KERN_INFO "ip ah init: can't add protocol\n");
	326	xfrm_unregister_type(&ah_type, AF_INET);
	327	return -EAGAIN;
	328	}
	329	return 0;
	330	}
	331
	332	static void __exit ah4_fini(void)
	333	{
	334	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
	335	printk(KERN_INFO "ip ah close: can't remove protocol\n");
	336	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
	337	printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
	338	}
	339
	340	module_init(ah4_init);
	341	module_exit(ah4_fini);
	342	MODULE_LICENSE("GPL");
d3d6dd3a	343	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);