[net-next-2.6.git] / net / ipv4 / xfrm4_mode_beet.c

/*
 * xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
 *
 * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
 *                    Miika Komu     <miika@iki.fi>
 *                    Herbert Xu     <herbert@gondor.apana.org.au>
 *                    Abhinav Pathak <abhinav.pathak@hiit.fi>
 *                    Jeff Ahrenholz <ahrenholz@gmail.com>
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/stringify.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/xfrm.h>

static void xfrm4_beet_make_header(struct sk_buff *skb)
{
	struct iphdr *iph = ip_hdr(skb);

	iph->ihl = 5;
	iph->version = 4;

	iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
	iph->tos = XFRM_MODE_SKB_CB(skb)->tos;

	iph->id = XFRM_MODE_SKB_CB(skb)->id;
	iph->frag_off = XFRM_MODE_SKB_CB(skb)->frag_off;
	iph->ttl = XFRM_MODE_SKB_CB(skb)->ttl;
}

/* Add encapsulation header.
 *
 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
 */
static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ip_beet_phdr *ph;
	struct iphdr *iph, *top_iph;
	int hdrlen, optlen;

	iph = ip_hdr(skb);

	hdrlen = 0;
	optlen = iph->ihl * 4 - sizeof(*iph);
	if (unlikely(optlen))
		hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);

	skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
				    hdrlen);
	skb->mac_header = skb->network_header +
			  offsetof(struct iphdr, protocol);
	skb->transport_header = skb->network_header + sizeof(*iph);

	xfrm4_beet_make_header(skb);

	ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - hdrlen);

	top_iph = ip_hdr(skb);

	if (unlikely(optlen)) {
		BUG_ON(optlen < 0);

		ph->padlen = 4 - (optlen & 4);
		ph->hdrlen = optlen / 8;
		ph->nexthdr = top_iph->protocol;
		if (ph->padlen)
			memset(ph + 1, IPOPT_NOP, ph->padlen);

		top_iph->protocol = IPPROTO_BEETPH;
		top_iph->ihl = sizeof(struct iphdr) / 4;
	}

	top_iph->saddr = x->props.saddr.a4;
	top_iph->daddr = x->id.daddr.a4;

	return 0;
}

static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
{
	struct iphdr *iph;
	int optlen = 0;
	int err = -EINVAL;

	if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
		struct ip_beet_phdr *ph;
		int phlen;

		if (!pskb_may_pull(skb, sizeof(*ph)))
			goto out;

		ph = (struct ip_beet_phdr *)skb->data;

		phlen = sizeof(*ph) + ph->padlen;
		optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
		if (optlen < 0 || optlen & 3 || optlen > 250)
			goto out;

		XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;

		if (!pskb_may_pull(skb, phlen));
			goto out;
		__skb_pull(skb, phlen);
	}

	skb_push(skb, sizeof(*iph));
	skb_reset_network_header(skb);

	memmove(skb->data - skb->mac_len, skb_mac_header(skb),
		skb->mac_len);
	skb_set_mac_header(skb, -skb->mac_len);

	xfrm4_beet_make_header(skb);

	iph = ip_hdr(skb);

	iph->ihl += optlen / 4;
	iph->tot_len = htons(skb->len);
	iph->daddr = x->sel.daddr.a4;
	iph->saddr = x->sel.saddr.a4;
	iph->check = 0;
	iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
	err = 0;
out:
	return err;
}

static struct xfrm_mode xfrm4_beet_mode = {
	.input2 = xfrm4_beet_input,
	.input = xfrm_prepare_input,
	.output2 = xfrm4_beet_output,
	.output = xfrm4_prepare_output,
	.owner = THIS_MODULE,
	.encap = XFRM_MODE_BEET,
	.flags = XFRM_MODE_FLAG_TUNNEL,
};

static int __init xfrm4_beet_init(void)
{
	return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
}

static void __exit xfrm4_beet_exit(void)
{
	int err;

	err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
	BUG_ON(err);
}

module_init(xfrm4_beet_init);
module_exit(xfrm4_beet_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);
Commit	Line	Data
0a69452c DB	1	/*
	2	* xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
	3	*
	4	* Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
	5	* Miika Komu <miika@iki.fi>
	6	* Herbert Xu <herbert@gondor.apana.org.au>
	7	* Abhinav Pathak <abhinav.pathak@hiit.fi>
	8	* Jeff Ahrenholz <ahrenholz@gmail.com>
	9	*/
	10
	11	#include <linux/init.h>
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/skbuff.h>
	15	#include <linux/stringify.h>
	16	#include <net/dst.h>
	17	#include <net/ip.h>
	18	#include <net/xfrm.h>
	19
227620e2 HX	20	static void xfrm4_beet_make_header(struct sk_buff *skb)
	21	{
	22	struct iphdr *iph = ip_hdr(skb);
	23
	24	iph->ihl = 5;
	25	iph->version = 4;
	26
	27	iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
	28	iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
	29
	30	iph->id = XFRM_MODE_SKB_CB(skb)->id;
	31	iph->frag_off = XFRM_MODE_SKB_CB(skb)->frag_off;
	32	iph->ttl = XFRM_MODE_SKB_CB(skb)->ttl;
	33	}
	34
0a69452c DB	35	/* Add encapsulation header.
	36	*
	37	* The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
0a69452c DB	38	*/
	39	static int xfrm4_beet_output(struct xfrm_state x, struct sk_buff skb)
	40	{
37fedd3a	41	struct ip_beet_phdr *ph;
ea2f10a3	42	struct iphdr iph, top_iph;
0a69452c DB	43	int hdrlen, optlen;
0a69452c DB	44
eddc9ec5	45	iph = ip_hdr(skb);
0a69452c DB	46
	47	hdrlen = 0;
	48	optlen = iph->ihl * 4 - sizeof(*iph);
	49	if (unlikely(optlen))
	50	hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
	51
7b277b1a HX	52	skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
7b277b1a HX	53	hdrlen);
37fedd3a HX	54	skb->mac_header = skb->network_header +
	55	offsetof(struct iphdr, protocol);
	56	skb->transport_header = skb->network_header + sizeof(*iph);
	57
227620e2 HX	58	xfrm4_beet_make_header(skb);
227620e2 HX	59
37fedd3a	60	ph = (struct ip_beet_phdr )__skb_pull(skb, sizeof(iph) - hdrlen);
0a69452c	61
37fedd3a	62	top_iph = ip_hdr(skb);
36cf9acf	63
0a69452c	64	if (unlikely(optlen)) {
0a69452c DB	65	BUG_ON(optlen < 0);
0a69452c DB	66
0a69452c	67	ph->padlen = 4 - (optlen & 4);
05d22446	68	ph->hdrlen = optlen / 8;
0a69452c	69	ph->nexthdr = top_iph->protocol;
04fef989 PM	70	if (ph->padlen)
04fef989 PM	71	memset(ph + 1, IPOPT_NOP, ph->padlen);
0a69452c DB	72
	73	top_iph->protocol = IPPROTO_BEETPH;
	74	top_iph->ihl = sizeof(struct iphdr) / 4;
	75	}
	76
	77	top_iph->saddr = x->props.saddr.a4;
	78	top_iph->daddr = x->id.daddr.a4;
	79
	80	return 0;
	81	}
	82
	83	static int xfrm4_beet_input(struct xfrm_state x, struct sk_buff skb)
	84	{
227620e2	85	struct iphdr *iph;
0a69452c	86	int optlen = 0;
0a69452c DB	87	int err = -EINVAL;
0a69452c DB	88
227620e2	89	if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
254d0d24	90	struct ip_beet_phdr *ph;
227620e2	91	int phlen;
0a69452c DB	92
	93	if (!pskb_may_pull(skb, sizeof(*ph)))
	94	goto out;
227620e2 HX	95
227620e2 HX	96	ph = (struct ip_beet_phdr *)skb->data;
0a69452c	97
d4b1e840	98	phlen = sizeof(*ph) + ph->padlen;
05d22446	99	optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
0a69452c DB	100	if (optlen < 0 \|\| optlen & 3 \|\| optlen > 250)
	101	goto out;
	102
227620e2	103	XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;
0a69452c	104
227620e2 HX	105	if (!pskb_may_pull(skb, phlen));
	106	goto out;
	107	__skb_pull(skb, phlen);
0a69452c DB	108	}
0a69452c DB	109
227620e2 HX	110	skb_push(skb, sizeof(*iph));
	111	skb_reset_network_header(skb);
	112
	113	memmove(skb->data - skb->mac_len, skb_mac_header(skb),
	114	skb->mac_len);
	115	skb_set_mac_header(skb, -skb->mac_len);
	116
	117	xfrm4_beet_make_header(skb);
0a69452c	118
eddc9ec5	119	iph = ip_hdr(skb);
227620e2 HX	120
	121	iph->ihl += optlen / 4;
	122	iph->tot_len = htons(skb->len);
0a69452c DB	123	iph->daddr = x->sel.daddr.a4;
0a69452c DB	124	iph->saddr = x->sel.saddr.a4;
0a69452c	125	iph->check = 0;
d56f90a7	126	iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
0a69452c DB	127	err = 0;
	128	out:
	129	return err;
	130	}
	131
	132	static struct xfrm_mode xfrm4_beet_mode = {
227620e2 HX	133	.input2 = xfrm4_beet_input,
227620e2 HX	134	.input = xfrm_prepare_input,
36cf9acf HX	135	.output2 = xfrm4_beet_output,
36cf9acf HX	136	.output = xfrm4_prepare_output,
0a69452c DB	137	.owner = THIS_MODULE,
0a69452c DB	138	.encap = XFRM_MODE_BEET,
1bfcb10f	139	.flags = XFRM_MODE_FLAG_TUNNEL,
0a69452c DB	140	};
	141
	142	static int __init xfrm4_beet_init(void)
	143	{
	144	return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
	145	}
	146
	147	static void __exit xfrm4_beet_exit(void)
	148	{
	149	int err;
	150
	151	err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
	152	BUG_ON(err);
	153	}
	154
	155	module_init(xfrm4_beet_init);
	156	module_exit(xfrm4_beet_exit);
	157	MODULE_LICENSE("GPL");
	158	MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);