[linux.git] / net / ipv4 / xfrm4_mode_beet.c

/*
 * xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
 *
 * Copyright (c) 2006 Diego Beltrami <[email protected]>
 *                    Miika Komu     <[email protected]>
 *                    Herbert Xu     <[email protected]>
 *                    Abhinav Pathak <[email protected]>
 *                    Jeff Ahrenholz <[email protected]>
 */

#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>

/* Add encapsulation header.
 *
 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
 * The following fields in it shall be filled in by x->type->output:
 *      tot_len
 *      check
 *
 * On exit, skb->h will be set to the start of the payload to be processed
 * by x->type->output and skb->nh will be set to the top IP header.
 */
static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct iphdr *iph, *top_iph = NULL;
	int hdrlen, optlen;

	iph = skb->nh.iph;
	skb->h.ipiph = iph;

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

	skb->nh.raw = skb_push(skb, x->props.header_len + hdrlen);
	top_iph = skb->nh.iph;
	hdrlen = iph->ihl * 4 - optlen;
	skb->h.raw += hdrlen;

	memmove(top_iph, iph, hdrlen);
	if (unlikely(optlen)) {
		struct ip_beet_phdr *ph;

		BUG_ON(optlen < 0);

		ph = (struct ip_beet_phdr *)skb->h.raw;
		ph->padlen = 4 - (optlen & 4);
		ph->hdrlen = (optlen + ph->padlen + sizeof(*ph)) / 8;
		ph->nexthdr = top_iph->protocol;

		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 = skb->nh.iph;
	int phlen = 0;
	int optlen = 0;
	__u8 ph_nexthdr = 0, protocol = 0;
	int err = -EINVAL;

	protocol = iph->protocol;

	if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
		struct ip_beet_phdr *ph = (struct ip_beet_phdr*)(iph + 1);

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

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

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

		ph_nexthdr = ph->nexthdr;
	}

	skb_push(skb, sizeof(*iph) - phlen + optlen);
	memmove(skb->data, skb->nh.raw, sizeof(*iph));
	skb->nh.raw = skb->data;

	iph = skb->nh.iph;
	iph->ihl = (sizeof(*iph) + optlen) / 4;
	iph->tot_len = htons(skb->len);
	iph->daddr = x->sel.daddr.a4;
	iph->saddr = x->sel.saddr.a4;
	if (ph_nexthdr)
		iph->protocol = ph_nexthdr;
	else
		iph->protocol = protocol;
	iph->check = 0;
	iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
	err = 0;
out:
	return err;
}

static struct xfrm_mode xfrm4_beet_mode = {
	.input = xfrm4_beet_input,
	.output = xfrm4_beet_output,
	.owner = THIS_MODULE,
	.encap = XFRM_MODE_BEET,
};

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 <[email protected]>
	5	* Miika Komu <[email protected]>
	6	* Herbert Xu <[email protected]>
	7	* Abhinav Pathak <[email protected]>
	8	* Jeff Ahrenholz <[email protected]>
	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
	20	/* Add encapsulation header.
	21	*
	22	* The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
	23	* The following fields in it shall be filled in by x->type->output:
	24	* tot_len
	25	* check
	26	*
	27	* On exit, skb->h will be set to the start of the payload to be processed
	28	* by x->type->output and skb->nh will be set to the top IP header.
	29	*/
	30	static int xfrm4_beet_output(struct xfrm_state x, struct sk_buff skb)
	31	{
	32	struct iphdr iph, top_iph = NULL;
	33	int hdrlen, optlen;
	34
	35	iph = skb->nh.iph;
	36	skb->h.ipiph = iph;
	37
	38	hdrlen = 0;
	39	optlen = iph->ihl * 4 - sizeof(*iph);
	40	if (unlikely(optlen))
	41	hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
	42
	43	skb->nh.raw = skb_push(skb, x->props.header_len + hdrlen);
	44	top_iph = skb->nh.iph;
	45	hdrlen = iph->ihl * 4 - optlen;
	46	skb->h.raw += hdrlen;
	47
	48	memmove(top_iph, iph, hdrlen);
	49	if (unlikely(optlen)) {
	50	struct ip_beet_phdr *ph;
	51
	52	BUG_ON(optlen < 0);
	53
	54	ph = (struct ip_beet_phdr *)skb->h.raw;
	55	ph->padlen = 4 - (optlen & 4);
	56	ph->hdrlen = (optlen + ph->padlen + sizeof(*ph)) / 8;
	57	ph->nexthdr = top_iph->protocol;
	58
	59	top_iph->protocol = IPPROTO_BEETPH;
	60	top_iph->ihl = sizeof(struct iphdr) / 4;
	61	}
	62
	63	top_iph->saddr = x->props.saddr.a4;
	64	top_iph->daddr = x->id.daddr.a4;
65
66	return 0;
67	}
68
69	static int xfrm4_beet_input(struct xfrm_state x, struct sk_buff skb)
70	{
71	struct iphdr *iph = skb->nh.iph;
72	int phlen = 0;
73	int optlen = 0;
74	__u8 ph_nexthdr = 0, protocol = 0;
75	int err = -EINVAL;
76
77	protocol = iph->protocol;
78
79	if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
80	struct ip_beet_phdr ph = (struct ip_beet_phdr)(iph + 1);
81
82	if (!pskb_may_pull(skb, sizeof(*ph)))
83	goto out;
84
85	phlen = ph->hdrlen * 8;
86	optlen = phlen - ph->padlen - sizeof(*ph);
87	if (optlen < 0 \|\| optlen & 3 \|\| optlen > 250)
88	goto out;
89
90	if (!pskb_may_pull(skb, phlen))
91	goto out;
92
93	ph_nexthdr = ph->nexthdr;
94	}
95
96	skb_push(skb, sizeof(*iph) - phlen + optlen);
97	memmove(skb->data, skb->nh.raw, sizeof(*iph));
98	skb->nh.raw = skb->data;
99
100	iph = skb->nh.iph;
101	iph->ihl = (sizeof(*iph) + optlen) / 4;
102	iph->tot_len = htons(skb->len);
103	iph->daddr = x->sel.daddr.a4;
104	iph->saddr = x->sel.saddr.a4;
105	if (ph_nexthdr)
106	iph->protocol = ph_nexthdr;
107	else
108	iph->protocol = protocol;
109	iph->check = 0;
110	iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
111	err = 0;
112	out:
113	return err;
114	}
115
116	static struct xfrm_mode xfrm4_beet_mode = {
117	.input = xfrm4_beet_input,
118	.output = xfrm4_beet_output,
119	.owner = THIS_MODULE,
120	.encap = XFRM_MODE_BEET,
121	};
122
123	static int __init xfrm4_beet_init(void)
124	{
125	return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
126	}
127
128	static void __exit xfrm4_beet_exit(void)
129	{
130	int err;
131
132	err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
133	BUG_ON(err);
134	}
135
136	module_init(xfrm4_beet_init);
137	module_exit(xfrm4_beet_exit);
138	MODULE_LICENSE("GPL");
139	MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);