[deliverable/linux.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 *top_iph;
	int hdrlen, optlen;

	hdrlen = 0;
	optlen = XFRM_MODE_SKB_CB(skb)->optlen;
	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(*top_iph);

	xfrm4_beet_make_header(skb);

	ph = (struct ip_beet_phdr *)
		__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - 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;
732c8bd5	42	struct iphdr *top_iph;
0a69452c DB	43	int hdrlen, optlen;
0a69452c DB	44
0a69452c	45	hdrlen = 0;
732c8bd5	46	optlen = XFRM_MODE_SKB_CB(skb)->optlen;
0a69452c DB	47	if (unlikely(optlen))
	48	hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
	49
7b277b1a HX	50	skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
7b277b1a HX	51	hdrlen);
37fedd3a HX	52	skb->mac_header = skb->network_header +
37fedd3a HX	53	offsetof(struct iphdr, protocol);
732c8bd5	54	skb->transport_header = skb->network_header + sizeof(*top_iph);
37fedd3a	55
227620e2 HX	56	xfrm4_beet_make_header(skb);
227620e2 HX	57
732c8bd5 HX	58	ph = (struct ip_beet_phdr *)
732c8bd5 HX	59	__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
0a69452c	60
37fedd3a	61	top_iph = ip_hdr(skb);
36cf9acf	62
0a69452c	63	if (unlikely(optlen)) {
0a69452c DB	64	BUG_ON(optlen < 0);
0a69452c DB	65
0a69452c	66	ph->padlen = 4 - (optlen & 4);
05d22446	67	ph->hdrlen = optlen / 8;
0a69452c	68	ph->nexthdr = top_iph->protocol;
04fef989 PM	69	if (ph->padlen)
04fef989 PM	70	memset(ph + 1, IPOPT_NOP, ph->padlen);
0a69452c DB	71
	72	top_iph->protocol = IPPROTO_BEETPH;
	73	top_iph->ihl = sizeof(struct iphdr) / 4;
	74	}
	75
	76	top_iph->saddr = x->props.saddr.a4;
	77	top_iph->daddr = x->id.daddr.a4;
	78
	79	return 0;
	80	}
	81
	82	static int xfrm4_beet_input(struct xfrm_state x, struct sk_buff skb)
	83	{
227620e2	84	struct iphdr *iph;
0a69452c	85	int optlen = 0;
0a69452c DB	86	int err = -EINVAL;
0a69452c DB	87
227620e2	88	if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
254d0d24	89	struct ip_beet_phdr *ph;
227620e2	90	int phlen;
0a69452c DB	91
	92	if (!pskb_may_pull(skb, sizeof(*ph)))
	93	goto out;
227620e2 HX	94
227620e2 HX	95	ph = (struct ip_beet_phdr *)skb->data;
0a69452c	96
d4b1e840	97	phlen = sizeof(*ph) + ph->padlen;
05d22446	98	optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
0a69452c DB	99	if (optlen < 0 \|\| optlen & 3 \|\| optlen > 250)
	100	goto out;
	101
227620e2	102	XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;
0a69452c	103
322c8a3c	104	if (!pskb_may_pull(skb, phlen))
227620e2 HX	105	goto out;
227620e2 HX	106	__skb_pull(skb, phlen);
0a69452c DB	107	}
0a69452c DB	108
227620e2 HX	109	skb_push(skb, sizeof(*iph));
	110	skb_reset_network_header(skb);
	111
	112	memmove(skb->data - skb->mac_len, skb_mac_header(skb),
	113	skb->mac_len);
	114	skb_set_mac_header(skb, -skb->mac_len);
	115
	116	xfrm4_beet_make_header(skb);
0a69452c	117
eddc9ec5	118	iph = ip_hdr(skb);
227620e2 HX	119
	120	iph->ihl += optlen / 4;
	121	iph->tot_len = htons(skb->len);
0a69452c DB	122	iph->daddr = x->sel.daddr.a4;
0a69452c DB	123	iph->saddr = x->sel.saddr.a4;
0a69452c	124	iph->check = 0;
d56f90a7	125	iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
0a69452c DB	126	err = 0;
	127	out:
	128	return err;
	129	}
	130
	131	static struct xfrm_mode xfrm4_beet_mode = {
227620e2 HX	132	.input2 = xfrm4_beet_input,
227620e2 HX	133	.input = xfrm_prepare_input,
36cf9acf HX	134	.output2 = xfrm4_beet_output,
36cf9acf HX	135	.output = xfrm4_prepare_output,
0a69452c DB	136	.owner = THIS_MODULE,
0a69452c DB	137	.encap = XFRM_MODE_BEET,
1bfcb10f	138	.flags = XFRM_MODE_FLAG_TUNNEL,
0a69452c DB	139	};
	140
	141	static int __init xfrm4_beet_init(void)
	142	{
	143	return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
	144	}
	145
	146	static void __exit xfrm4_beet_exit(void)
	147	{
	148	int err;
	149
	150	err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
	151	BUG_ON(err);
	152	}
	153
	154	module_init(xfrm4_beet_init);
	155	module_exit(xfrm4_beet_exit);
	156	MODULE_LICENSE("GPL");
	157	MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);