[deliverable/linux.git] / net / ipv4 / xfrm4_mode_tunnel.c

/*
 * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
 *
 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/gfp.h>
#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/inet_ecn.h>
#include <net/ip.h>
#include <net/xfrm.h>

static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
{
	struct iphdr *inner_iph = ipip_hdr(skb);

	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
		IP_ECN_set_ce(inner_iph);
}

/* Add encapsulation header.
 *
 * The top IP header will be constructed per RFC 2401.
 */
static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct dst_entry *dst = skb_dst(skb);
	struct iphdr *top_iph;
	int flags;

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

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

	top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);

	/* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
	if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
		top_iph->tos = 0;
	else
		top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
	top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
					    XFRM_MODE_SKB_CB(skb)->tos);

	flags = x->props.flags;
	if (flags & XFRM_STATE_NOECN)
		IP_ECN_clear(top_iph);

	top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
		0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));

	top_iph->ttl = ip4_dst_hoplimit(dst->child);

	top_iph->saddr = x->props.saddr.a4;
	top_iph->daddr = x->id.daddr.a4;
	ip_select_ident(dev_net(dst->dev), skb, NULL);

	return 0;
}

static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int err = -EINVAL;

	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
		goto out;

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

	err = skb_unclone(skb, GFP_ATOMIC);
	if (err)
		goto out;

	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
		ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
	if (!(x->props.flags & XFRM_STATE_NOECN))
		ipip_ecn_decapsulate(skb);

	skb_reset_network_header(skb);
	skb_mac_header_rebuild(skb);

	err = 0;

out:
	return err;
}

static struct xfrm_mode xfrm4_tunnel_mode = {
	.input2 = xfrm4_mode_tunnel_input,
	.input = xfrm_prepare_input,
	.output2 = xfrm4_mode_tunnel_output,
	.output = xfrm4_prepare_output,
	.owner = THIS_MODULE,
	.encap = XFRM_MODE_TUNNEL,
	.flags = XFRM_MODE_FLAG_TUNNEL,
};

static int __init xfrm4_mode_tunnel_init(void)
{
	return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
}

static void __exit xfrm4_mode_tunnel_exit(void)
{
	int err;

	err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
	BUG_ON(err);
}

module_init(xfrm4_mode_tunnel_init);
module_exit(xfrm4_mode_tunnel_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);
Commit	Line	Data
b59f45d0 HX	1	/*
	2	* xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
	3	*
	4	* Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
	5	*/
	6
5a0e3ad6	7	#include <linux/gfp.h>
b59f45d0 HX	8	#include <linux/init.h>
	9	#include <linux/kernel.h>
	10	#include <linux/module.h>
	11	#include <linux/skbuff.h>
	12	#include <linux/stringify.h>
	13	#include <net/dst.h>
	14	#include <net/inet_ecn.h>
	15	#include <net/ip.h>
	16	#include <net/xfrm.h>
	17
	18	static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
	19	{
b0061ce4	20	struct iphdr *inner_iph = ipip_hdr(skb);
b59f45d0	21
227620e2	22	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
b59f45d0 HX	23	IP_ECN_set_ce(inner_iph);
	24	}
	25
	26	/* Add encapsulation header.
	27	*
ceb1eec8	28	* The top IP header will be constructed per RFC 2401.
b59f45d0	29	*/
195ad6a3	30	static int xfrm4_mode_tunnel_output(struct xfrm_state x, struct sk_buff skb)
b59f45d0	31	{
adf30907	32	struct dst_entry *dst = skb_dst(skb);
36cf9acf	33	struct iphdr *top_iph;
b59f45d0 HX	34	int flags;
b59f45d0 HX	35
7b277b1a	36	skb_set_network_header(skb, -x->props.header_len);
37fedd3a HX	37	skb->mac_header = skb->network_header +
37fedd3a HX	38	offsetof(struct iphdr, protocol);
36cf9acf	39	skb->transport_header = skb->network_header + sizeof(*top_iph);
eddc9ec5	40	top_iph = ip_hdr(skb);
b59f45d0 HX	41
	42	top_iph->ihl = 5;
	43	top_iph->version = 4;
	44
adf30907	45	top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
c82f963e	46
a947b0a9 ND	47	/* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
	48	if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
	49	top_iph->tos = 0;
	50	else
	51	top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
	52	top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
36cf9acf	53	XFRM_MODE_SKB_CB(skb)->tos);
b59f45d0	54
36cf9acf	55	flags = x->props.flags;
b59f45d0 HX	56	if (flags & XFRM_STATE_NOECN)
	57	IP_ECN_clear(top_iph);
	58
36cf9acf	59	top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
fe833fca	60	0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
b59f45d0	61
323e126f	62	top_iph->ttl = ip4_dst_hoplimit(dst->child);
b59f45d0 HX	63
	64	top_iph->saddr = x->props.saddr.a4;
	65	top_iph->daddr = x->id.daddr.a4;
b6a7719a	66	ip_select_ident(dev_net(dst->dev), skb, NULL);
b59f45d0	67
b59f45d0 HX	68	return 0;
	69	}
	70
195ad6a3	71	static int xfrm4_mode_tunnel_input(struct xfrm_state x, struct sk_buff skb)
b59f45d0	72	{
b59f45d0 HX	73	int err = -EINVAL;
b59f45d0 HX	74
227620e2 HX	75	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
227620e2 HX	76	goto out;
c82f963e	77
b59f45d0 HX	78	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	79	goto out;
	80
9aac22de	81	err = skb_unclone(skb, GFP_ATOMIC);
9aac22de	82	if (err)
b59f45d0 HX	83	goto out;
b59f45d0 HX	84
227620e2 HX	85	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
	86	ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
	87	if (!(x->props.flags & XFRM_STATE_NOECN))
	88	ipip_ecn_decapsulate(skb);
	89
c1d2bbe1	90	skb_reset_network_header(skb);
03606895 ED	91	skb_mac_header_rebuild(skb);
03606895 ED	92
b59f45d0 HX	93	err = 0;
	94
	95	out:
	96	return err;
	97	}
	98
	99	static struct xfrm_mode xfrm4_tunnel_mode = {
195ad6a3	100	.input2 = xfrm4_mode_tunnel_input,
227620e2	101	.input = xfrm_prepare_input,
195ad6a3	102	.output2 = xfrm4_mode_tunnel_output,
36cf9acf	103	.output = xfrm4_prepare_output,
b59f45d0 HX	104	.owner = THIS_MODULE,
b59f45d0 HX	105	.encap = XFRM_MODE_TUNNEL,
1bfcb10f	106	.flags = XFRM_MODE_FLAG_TUNNEL,
b59f45d0 HX	107	};
b59f45d0 HX	108
195ad6a3	109	static int __init xfrm4_mode_tunnel_init(void)
b59f45d0 HX	110	{
	111	return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
	112	}
	113
195ad6a3	114	static void __exit xfrm4_mode_tunnel_exit(void)
b59f45d0 HX	115	{
	116	int err;
	117
	118	err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
	119	BUG_ON(err);
	120	}
	121
195ad6a3 HX	122	module_init(xfrm4_mode_tunnel_init);
195ad6a3 HX	123	module_exit(xfrm4_mode_tunnel_exit);
b59f45d0 HX	124	MODULE_LICENSE("GPL");
b59f45d0 HX	125	MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);