[net-next-2.6.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>


/* 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 = ip_auth_hdr(skb);
	ah->nexthdr = *skb_mac_header(skb);
	*skb_mac_header(skb) = IPPROTO_AH;

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

	ahp = x->data;
	ah->hdrlen  = (XFRM_ALIGN8(sizeof(*ah) + 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));
	}

	err = 0;

error:
	return err;
}

static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int ah_hlen;
	int ihl;
	int nexthdr;
	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(*ah)))
		goto out;

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

	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
	    ah_hlen != XFRM_ALIGN8(sizeof(*ah) + 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;
		}
	}
	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 nexthdr;

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
	12
	13	/* Clear mutable options and find final destination to substitute
	14	* into IP header for icv calculation. Options are already checked
	15	* for validity, so paranoia is not required. */
	16
d5a0a1e3	17	static int ip_clear_mutable_options(struct iphdr iph, __be32 daddr)
1da177e4 LT	18	{
	19	unsigned char * optptr = (unsigned char*)(iph+1);
	20	int l = iph->ihl*4 - sizeof(struct iphdr);
	21	int optlen;
	22
	23	while (l > 0) {
	24	switch (*optptr) {
	25	case IPOPT_END:
	26	return 0;
	27	case IPOPT_NOOP:
	28	l--;
	29	optptr++;
	30	continue;
	31	}
	32	optlen = optptr[1];
	33	if (optlen<2 \|\| optlen>l)
	34	return -EINVAL;
	35	switch (*optptr) {
	36	case IPOPT_SEC:
	37	case 0x85: /* Some "Extended Security" crap. */
11a03f78	38	case IPOPT_CIPSO:
1da177e4 LT	39	case IPOPT_RA:
	40	case 0x80\|21: /* RFC1770 */
	41	break;
	42	case IPOPT_LSRR:
	43	case IPOPT_SSRR:
	44	if (optlen < 6)
	45	return -EINVAL;
	46	memcpy(daddr, optptr+optlen-4, 4);
	47	/* Fall through */
	48	default:
96fe1c02	49	memset(optptr, 0, optlen);
1da177e4 LT	50	}
	51	l -= optlen;
	52	optptr += optlen;
	53	}
	54	return 0;
	55	}
	56
	57	static int ah_output(struct xfrm_state x, struct sk_buff skb)
	58	{
	59	int err;
	60	struct iphdr iph, top_iph;
	61	struct ip_auth_hdr *ah;
	62	struct ah_data *ahp;
	63	union {
	64	struct iphdr iph;
	65	char buf[60];
	66	} tmp_iph;
	67
7b277b1a	68	skb_push(skb, -skb_network_offset(skb));
eddc9ec5	69	top_iph = ip_hdr(skb);
1da177e4 LT	70	iph = &tmp_iph.iph;
	71
	72	iph->tos = top_iph->tos;
	73	iph->ttl = top_iph->ttl;
	74	iph->frag_off = top_iph->frag_off;
	75
	76	if (top_iph->ihl != 5) {
	77	iph->daddr = top_iph->daddr;
	78	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	79	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	80	if (err)
	81	goto error;
	82	}
	83
87bdc48d	84	ah = ip_auth_hdr(skb);
37fedd3a HX	85	ah->nexthdr = *skb_mac_header(skb);
37fedd3a HX	86	*skb_mac_header(skb) = IPPROTO_AH;
1da177e4 LT	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;
1da177e4 LT	92	top_iph->check = 0;
	93
	94	ahp = x->data;
87bdc48d	95	ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
1da177e4 LT	96
	97	ah->reserved = 0;
	98	ah->spi = x->id.spi;
436a0a40	99	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
b7c6538c HX	100
b7c6538c HX	101	spin_lock_bh(&x->lock);
07d4ee58	102	err = ah_mac_digest(ahp, skb, ah->auth_data);
b7c6538c HX	103	memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
	104	spin_unlock_bh(&x->lock);
	105
07d4ee58 HX	106	if (err)
07d4ee58 HX	107	goto error;
1da177e4 LT	108
	109	top_iph->tos = iph->tos;
	110	top_iph->ttl = iph->ttl;
	111	top_iph->frag_off = iph->frag_off;
	112	if (top_iph->ihl != 5) {
	113	top_iph->daddr = iph->daddr;
	114	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	115	}
	116
1da177e4 LT	117	err = 0;
	118
	119	error:
	120	return err;
	121	}
	122
e695633e	123	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	124	{
1da177e4 LT	125	int ah_hlen;
31a4ab93	126	int ihl;
631a6698	127	int nexthdr;
07d4ee58	128	int err = -EINVAL;
1da177e4 LT	129	struct iphdr *iph;
	130	struct ip_auth_hdr *ah;
	131	struct ah_data *ahp;
	132	char work_buf[60];
	133
87bdc48d	134	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	135	goto out;
1da177e4 LT	136
87bdc48d	137	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	138	ahp = x->data;
631a6698	139	nexthdr = ah->nexthdr;
1da177e4	140	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	141
87bdc48d HX	142	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
87bdc48d HX	143	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
1da177e4 LT	144	goto out;
	145
	146	if (!pskb_may_pull(skb, ah_hlen))
	147	goto out;
	148
	149	/* We are going to _remove_ AH header to keep sockets happy,
	150	* so... Later this can change. */
	151	if (skb_cloned(skb) &&
	152	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	153	goto out;
	154
	155	skb->ip_summed = CHECKSUM_NONE;
	156
87bdc48d	157	ah = (struct ip_auth_hdr *)skb->data;
eddc9ec5	158	iph = ip_hdr(skb);
1da177e4	159
d56f90a7	160	ihl = skb->data - skb_network_header(skb);
31a4ab93	161	memcpy(work_buf, iph, ihl);
1da177e4 LT	162
	163	iph->ttl = 0;
	164	iph->tos = 0;
	165	iph->frag_off = 0;
	166	iph->check = 0;
31a4ab93	167	if (ihl > sizeof(*iph)) {
d5a0a1e3	168	__be32 dummy;
1da177e4 LT	169	if (ip_clear_mutable_options(iph, &dummy))
	170	goto out;
	171	}
e905a9ed	172	{
1da177e4	173	u8 auth_data[MAX_AH_AUTH_LEN];
e905a9ed	174
1da177e4	175	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
31a4ab93	176	skb_push(skb, ihl);
07d4ee58 HX	177	err = ah_mac_digest(ahp, skb, ah->auth_data);
	178	if (err)
	179	goto out;
	180	err = -EINVAL;
	181	if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
1da177e4 LT	182	x->stats.integrity_failed++;
	183	goto out;
	184	}
	185	}
b0e380b1	186	skb->network_header += ah_hlen;
badff6d0	187	memcpy(skb_network_header(skb), work_buf, ihl);
b0e380b1	188	skb->transport_header = skb->network_header;
31a4ab93	189	__skb_pull(skb, ah_hlen + ihl);
1da177e4	190
631a6698	191	return nexthdr;
1da177e4 LT	192
1da177e4 LT	193	out:
07d4ee58	194	return err;
1da177e4 LT	195	}
	196
	197	static void ah4_err(struct sk_buff *skb, u32 info)
	198	{
	199	struct iphdr iph = (struct iphdr)skb->data;
	200	struct ip_auth_hdr ah = (struct ip_auth_hdr)(skb->data+(iph->ihl<<2));
	201	struct xfrm_state *x;
	202
88c7664f ACM	203	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	204	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	205	return;
	206
	207	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
	208	if (!x)
	209	return;
	210	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
	211	ntohl(ah->spi), ntohl(iph->daddr));
	212	xfrm_state_put(x);
	213	}
	214
72cb6962	215	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	216	{
	217	struct ah_data *ahp = NULL;
	218	struct xfrm_algo_desc *aalg_desc;
07d4ee58	219	struct crypto_hash *tfm;
1da177e4 LT	220
	221	if (!x->aalg)
	222	goto error;
	223
1da177e4 LT	224	if (x->encap)
	225	goto error;
	226
0da974f4	227	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
1da177e4 LT	228	if (ahp == NULL)
	229	return -ENOMEM;
	230
07d4ee58 HX	231	tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
	232	if (IS_ERR(tfm))
	233	goto error;
	234
	235	ahp->tfm = tfm;
bc31d3b2 HX	236	if (crypto_hash_setkey(tfm, x->aalg->alg_key,
bc31d3b2 HX	237	(x->aalg->alg_key_len + 7) / 8))
1da177e4	238	goto error;
e905a9ed	239
1da177e4 LT	240	/*
	241	* Lookup the algorithm description maintained by xfrm_algo,
	242	* verify crypto transform properties, and store information
	243	* we need for AH processing. This lookup cannot fail here
07d4ee58	244	* after a successful crypto_alloc_hash().
1da177e4 LT	245	*/
	246	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	247	BUG_ON(!aalg_desc);
	248
	249	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58	250	crypto_hash_digestsize(tfm)) {
1da177e4	251	printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
07d4ee58	252	x->aalg->alg_name, crypto_hash_digestsize(tfm),
1da177e4 LT	253	aalg_desc->uinfo.auth.icv_fullbits/8);
	254	goto error;
	255	}
e905a9ed	256
1da177e4 LT	257	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
1da177e4 LT	258	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
e905a9ed	259
1da177e4	260	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
e905a9ed	261
1da177e4 LT	262	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	263	if (!ahp->work_icv)
	264	goto error;
e905a9ed	265
87bdc48d HX	266	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
87bdc48d HX	267	ahp->icv_trunc_len);
7e49e6de	268	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	269	x->props.header_len += sizeof(struct iphdr);
	270	x->data = ahp;
	271
	272	return 0;
	273
	274	error:
	275	if (ahp) {
573dbd95	276	kfree(ahp->work_icv);
07d4ee58	277	crypto_free_hash(ahp->tfm);
1da177e4 LT	278	kfree(ahp);
	279	}
	280	return -EINVAL;
	281	}
	282
	283	static void ah_destroy(struct xfrm_state *x)
	284	{
	285	struct ah_data *ahp = x->data;
	286
	287	if (!ahp)
	288	return;
	289
573dbd95 JJ	290	kfree(ahp->work_icv);
573dbd95 JJ	291	ahp->work_icv = NULL;
07d4ee58	292	crypto_free_hash(ahp->tfm);
573dbd95	293	ahp->tfm = NULL;
1da177e4 LT	294	kfree(ahp);
	295	}
	296
	297
	298	static struct xfrm_type ah_type =
	299	{
	300	.description = "AH4",
	301	.owner = THIS_MODULE,
	302	.proto = IPPROTO_AH,
436a0a40	303	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	304	.init_state = ah_init_state,
	305	.destructor = ah_destroy,
	306	.input = ah_input,
	307	.output = ah_output
	308	};
	309
	310	static struct net_protocol ah4_protocol = {
	311	.handler = xfrm4_rcv,
	312	.err_handler = ah4_err,
	313	.no_policy = 1,
	314	};
	315
	316	static int __init ah4_init(void)
	317	{
	318	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
	319	printk(KERN_INFO "ip ah init: can't add xfrm type\n");
	320	return -EAGAIN;
	321	}
	322	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
	323	printk(KERN_INFO "ip ah init: can't add protocol\n");
	324	xfrm_unregister_type(&ah_type, AF_INET);
	325	return -EAGAIN;
	326	}
	327	return 0;
	328	}
	329
	330	static void __exit ah4_fini(void)
	331	{
	332	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
	333	printk(KERN_INFO "ip ah close: can't remove protocol\n");
	334	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
	335	printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
	336	}
	337
	338	module_init(ah4_init);
	339	module_exit(ah4_fini);
	340	MODULE_LICENSE("GPL");
d3d6dd3a	341	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);