[deliverable/linux.git] / net / ipv6 / xfrm6_mode_tunnel.c

/*
 * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
 *
 * Copyright (C) 2002 USAGI/WIDE Project
 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/stringify.h>
#include <net/dsfield.h>
#include <net/dst.h>
#include <net/inet_ecn.h>
#include <net/ipv6.h>
#include <net/xfrm.h>

static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
{
	struct ipv6hdr *outer_iph = ipv6_hdr(skb);
	struct ipv6hdr *inner_iph = ipipv6_hdr(skb);

	if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
		IP6_ECN_set_ce(inner_iph);
}

static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb)
{
	if (INET_ECN_is_ce(ipv6_get_dsfield(ipv6_hdr(skb))))
			IP_ECN_set_ce(ipip_hdr(skb));
}

/* Add encapsulation header.
 *
 * The top IP header will be constructed per RFC 2401.  The following fields
 * in it shall be filled in by x->type->output:
 *	payload_len
 */
static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct dst_entry *dst = skb->dst;
	struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
	struct ipv6hdr *iph, *top_iph;
	int dsfield;

	iph = ipv6_hdr(skb);

	skb_set_network_header(skb, -x->props.header_len);
	skb->mac_header = skb->network_header +
			  offsetof(struct ipv6hdr, nexthdr);
	skb->transport_header = skb->network_header + sizeof(*iph);
	top_iph = ipv6_hdr(skb);

	top_iph->version = 6;
	if (xdst->route->ops->family == AF_INET6) {
		top_iph->priority = iph->priority;
		top_iph->flow_lbl[0] = iph->flow_lbl[0];
		top_iph->flow_lbl[1] = iph->flow_lbl[1];
		top_iph->flow_lbl[2] = iph->flow_lbl[2];
		top_iph->nexthdr = IPPROTO_IPV6;
	} else {
		top_iph->priority = 0;
		top_iph->flow_lbl[0] = 0;
		top_iph->flow_lbl[1] = 0;
		top_iph->flow_lbl[2] = 0;
		top_iph->nexthdr = IPPROTO_IPIP;
	}
	dsfield = ipv6_get_dsfield(top_iph);
	dsfield = INET_ECN_encapsulate(dsfield, dsfield);
	if (x->props.flags & XFRM_STATE_NOECN)
		dsfield &= ~INET_ECN_MASK;
	ipv6_change_dsfield(top_iph, 0, dsfield);
	top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
	ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
	ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
	skb->protocol = htons(ETH_P_IPV6);
	return 0;
}

static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int err = -EINVAL;
	const unsigned char *old_mac;
	const unsigned char *nh = skb_network_header(skb);

	if (nh[IP6CB(skb)->nhoff] != IPPROTO_IPV6 &&
	    nh[IP6CB(skb)->nhoff] != IPPROTO_IPIP)
		goto out;
	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
		goto out;

	if (skb_cloned(skb) &&
	    (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
		goto out;

	nh = skb_network_header(skb);
	if (nh[IP6CB(skb)->nhoff] == IPPROTO_IPV6) {
		if (x->props.flags & XFRM_STATE_DECAP_DSCP)
			ipv6_copy_dscp(ipv6_hdr(skb), ipipv6_hdr(skb));
		if (!(x->props.flags & XFRM_STATE_NOECN))
			ipip6_ecn_decapsulate(skb);
	} else {
		if (!(x->props.flags & XFRM_STATE_NOECN))
			ip6ip_ecn_decapsulate(skb);
		skb->protocol = htons(ETH_P_IP);
	}
	old_mac = skb_mac_header(skb);
	skb_set_mac_header(skb, -skb->mac_len);
	memmove(skb_mac_header(skb), old_mac, skb->mac_len);
	skb_reset_network_header(skb);
	err = 0;

out:
	return err;
}

static struct xfrm_mode xfrm6_tunnel_mode = {
	.input = xfrm6_tunnel_input,
	.output = xfrm6_tunnel_output,
	.owner = THIS_MODULE,
	.encap = XFRM_MODE_TUNNEL,
};

static int __init xfrm6_tunnel_init(void)
{
	return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
}

static void __exit xfrm6_tunnel_exit(void)
{
	int err;

	err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
	BUG_ON(err);
}

module_init(xfrm6_tunnel_init);
module_exit(xfrm6_tunnel_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);
Commit	Line	Data
b59f45d0 HX	1	/*
	2	* xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
	3	*
	4	* Copyright (C) 2002 USAGI/WIDE Project
	5	* Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
	6	*/
	7
	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/dsfield.h>
	14	#include <net/dst.h>
	15	#include <net/inet_ecn.h>
	16	#include <net/ipv6.h>
	17	#include <net/xfrm.h>
	18
	19	static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
	20	{
0660e03f	21	struct ipv6hdr *outer_iph = ipv6_hdr(skb);
39b89160	22	struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
b59f45d0 HX	23
	24	if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
	25	IP6_ECN_set_ce(inner_iph);
	26	}
	27
43372262 MK	28	static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb)
43372262 MK	29	{
0660e03f	30	if (INET_ECN_is_ce(ipv6_get_dsfield(ipv6_hdr(skb))))
b0061ce4	31	IP_ECN_set_ce(ipip_hdr(skb));
43372262 MK	32	}
43372262 MK	33
b59f45d0 HX	34	/* Add encapsulation header.
	35	*
	36	* The top IP header will be constructed per RFC 2401. The following fields
	37	* in it shall be filled in by x->type->output:
	38	* payload_len
b59f45d0	39	*/
eb878e84	40	static int xfrm6_tunnel_output(struct xfrm_state x, struct sk_buff skb)
b59f45d0 HX	41	{
b59f45d0 HX	42	struct dst_entry *dst = skb->dst;
43372262	43	struct xfrm_dst xdst = (struct xfrm_dst)dst;
b59f45d0 HX	44	struct ipv6hdr iph, top_iph;
	45	int dsfield;
	46
0660e03f	47	iph = ipv6_hdr(skb);
b59f45d0	48
7b277b1a	49	skb_set_network_header(skb, -x->props.header_len);
37fedd3a HX	50	skb->mac_header = skb->network_header +
	51	offsetof(struct ipv6hdr, nexthdr);
	52	skb->transport_header = skb->network_header + sizeof(*iph);
0660e03f	53	top_iph = ipv6_hdr(skb);
b59f45d0 HX	54
b59f45d0 HX	55	top_iph->version = 6;
43372262 MK	56	if (xdst->route->ops->family == AF_INET6) {
	57	top_iph->priority = iph->priority;
	58	top_iph->flow_lbl[0] = iph->flow_lbl[0];
	59	top_iph->flow_lbl[1] = iph->flow_lbl[1];
	60	top_iph->flow_lbl[2] = iph->flow_lbl[2];
	61	top_iph->nexthdr = IPPROTO_IPV6;
	62	} else {
	63	top_iph->priority = 0;
	64	top_iph->flow_lbl[0] = 0;
	65	top_iph->flow_lbl[1] = 0;
	66	top_iph->flow_lbl[2] = 0;
	67	top_iph->nexthdr = IPPROTO_IPIP;
	68	}
b59f45d0 HX	69	dsfield = ipv6_get_dsfield(top_iph);
	70	dsfield = INET_ECN_encapsulate(dsfield, dsfield);
	71	if (x->props.flags & XFRM_STATE_NOECN)
	72	dsfield &= ~INET_ECN_MASK;
	73	ipv6_change_dsfield(top_iph, 0, dsfield);
b59f45d0 HX	74	top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
	75	ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
	76	ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
f282d45c	77	skb->protocol = htons(ETH_P_IPV6);
b59f45d0 HX	78	return 0;
	79	}
	80
	81	static int xfrm6_tunnel_input(struct xfrm_state x, struct sk_buff skb)
	82	{
	83	int err = -EINVAL;
39f69c6f	84	const unsigned char *old_mac;
d56f90a7	85	const unsigned char *nh = skb_network_header(skb);
b59f45d0	86
d56f90a7 ACM	87	if (nh[IP6CB(skb)->nhoff] != IPPROTO_IPV6 &&
d56f90a7 ACM	88	nh[IP6CB(skb)->nhoff] != IPPROTO_IPIP)
b59f45d0 HX	89	goto out;
	90	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
	91	goto out;
	92
	93	if (skb_cloned(skb) &&
	94	(err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
	95	goto out;
	96
d56f90a7 ACM	97	nh = skb_network_header(skb);
d56f90a7 ACM	98	if (nh[IP6CB(skb)->nhoff] == IPPROTO_IPV6) {
43372262	99	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
39b89160	100	ipv6_copy_dscp(ipv6_hdr(skb), ipipv6_hdr(skb));
43372262 MK	101	if (!(x->props.flags & XFRM_STATE_NOECN))
	102	ipip6_ecn_decapsulate(skb);
	103	} else {
	104	if (!(x->props.flags & XFRM_STATE_NOECN))
	105	ip6ip_ecn_decapsulate(skb);
	106	skb->protocol = htons(ETH_P_IP);
	107	}
98e399f8	108	old_mac = skb_mac_header(skb);
39f69c6f	109	skb_set_mac_header(skb, -skb->mac_len);
98e399f8	110	memmove(skb_mac_header(skb), old_mac, skb->mac_len);
c1d2bbe1	111	skb_reset_network_header(skb);
b59f45d0 HX	112	err = 0;
	113
	114	out:
	115	return err;
	116	}
	117
	118	static struct xfrm_mode xfrm6_tunnel_mode = {
	119	.input = xfrm6_tunnel_input,
	120	.output = xfrm6_tunnel_output,
	121	.owner = THIS_MODULE,
	122	.encap = XFRM_MODE_TUNNEL,
	123	};
	124
	125	static int __init xfrm6_tunnel_init(void)
	126	{
	127	return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
	128	}
	129
	130	static void __exit xfrm6_tunnel_exit(void)
	131	{
	132	int err;
	133
	134	err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
	135	BUG_ON(err);
	136	}
	137
	138	module_init(xfrm6_tunnel_init);
	139	module_exit(xfrm6_tunnel_exit);
	140	MODULE_LICENSE("GPL");
	141	MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);