[net-next-2.6.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 = skb->nh.ipv6h;
	struct ipv6hdr *inner_iph = skb->h.ipv6h;

	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(skb->nh.ipv6h)))
			IP_ECN_set_ce(skb->h.ipiph);
}

/* 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
 *
 * On exit, skb->h will be set to the start of the encapsulation header to be
 * filled in by x->type->output and skb->nh will be set to the nextheader field
 * of the extension header directly preceding the encapsulation header, or in
 * its absence, that of the top IP header.  The value of skb->data will always
 * point to the top IP header.
 */
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;

	skb_push(skb, x->props.header_len);
	iph = skb->nh.ipv6h;

	skb_reset_network_header(skb);
	top_iph = skb->nh.ipv6h;
	skb->nh.raw = &top_iph->nexthdr;
	skb->h.ipv6h = top_iph + 1;

	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);
	return 0;
}

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

	if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6
	    && skb->nh.raw[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;

	if (skb->nh.raw[IP6CB(skb)->nhoff] == IPPROTO_IPV6) {
		if (x->props.flags & XFRM_STATE_DECAP_DSCP)
			ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
		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	{
	21	struct ipv6hdr *outer_iph = skb->nh.ipv6h;
	22	struct ipv6hdr *inner_iph = skb->h.ipv6h;
	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)
	29	{
	30	if (INET_ECN_is_ce(ipv6_get_dsfield(skb->nh.ipv6h)))
	31	IP_ECN_set_ce(skb->h.ipiph);
	32	}
	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
	39	*
	40	* On exit, skb->h will be set to the start of the encapsulation header to be
	41	* filled in by x->type->output and skb->nh will be set to the nextheader field
	42	* of the extension header directly preceding the encapsulation header, or in
	43	* its absence, that of the top IP header. The value of skb->data will always
	44	* point to the top IP header.
	45	*/
eb878e84	46	static int xfrm6_tunnel_output(struct xfrm_state x, struct sk_buff skb)
b59f45d0 HX	47	{
b59f45d0 HX	48	struct dst_entry *dst = skb->dst;
43372262	49	struct xfrm_dst xdst = (struct xfrm_dst)dst;
b59f45d0 HX	50	struct ipv6hdr iph, top_iph;
	51	int dsfield;
	52
	53	skb_push(skb, x->props.header_len);
	54	iph = skb->nh.ipv6h;
	55
c1d2bbe1	56	skb_reset_network_header(skb);
b59f45d0 HX	57	top_iph = skb->nh.ipv6h;
	58	skb->nh.raw = &top_iph->nexthdr;
	59	skb->h.ipv6h = top_iph + 1;
	60
	61	top_iph->version = 6;
43372262 MK	62	if (xdst->route->ops->family == AF_INET6) {
	63	top_iph->priority = iph->priority;
	64	top_iph->flow_lbl[0] = iph->flow_lbl[0];
	65	top_iph->flow_lbl[1] = iph->flow_lbl[1];
	66	top_iph->flow_lbl[2] = iph->flow_lbl[2];
	67	top_iph->nexthdr = IPPROTO_IPV6;
	68	} else {
	69	top_iph->priority = 0;
	70	top_iph->flow_lbl[0] = 0;
	71	top_iph->flow_lbl[1] = 0;
	72	top_iph->flow_lbl[2] = 0;
	73	top_iph->nexthdr = IPPROTO_IPIP;
	74	}
b59f45d0 HX	75	dsfield = ipv6_get_dsfield(top_iph);
	76	dsfield = INET_ECN_encapsulate(dsfield, dsfield);
	77	if (x->props.flags & XFRM_STATE_NOECN)
	78	dsfield &= ~INET_ECN_MASK;
	79	ipv6_change_dsfield(top_iph, 0, dsfield);
b59f45d0 HX	80	top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
	81	ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
	82	ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
	83	return 0;
	84	}
	85
	86	static int xfrm6_tunnel_input(struct xfrm_state x, struct sk_buff skb)
	87	{
	88	int err = -EINVAL;
39f69c6f	89	const unsigned char *old_mac;
b59f45d0	90
43372262 MK	91	if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6
43372262 MK	92	&& skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPIP)
b59f45d0 HX	93	goto out;
	94	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
	95	goto out;
	96
	97	if (skb_cloned(skb) &&
	98	(err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
	99	goto out;
	100
43372262 MK	101	if (skb->nh.raw[IP6CB(skb)->nhoff] == IPPROTO_IPV6) {
	102	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
	103	ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
	104	if (!(x->props.flags & XFRM_STATE_NOECN))
	105	ipip6_ecn_decapsulate(skb);
	106	} else {
	107	if (!(x->props.flags & XFRM_STATE_NOECN))
	108	ip6ip_ecn_decapsulate(skb);
	109	skb->protocol = htons(ETH_P_IP);
	110	}
98e399f8	111	old_mac = skb_mac_header(skb);
39f69c6f	112	skb_set_mac_header(skb, -skb->mac_len);
98e399f8	113	memmove(skb_mac_header(skb), old_mac, skb->mac_len);
c1d2bbe1	114	skb_reset_network_header(skb);
b59f45d0 HX	115	err = 0;
	116
	117	out:
	118	return err;
	119	}
	120
	121	static struct xfrm_mode xfrm6_tunnel_mode = {
	122	.input = xfrm6_tunnel_input,
	123	.output = xfrm6_tunnel_output,
	124	.owner = THIS_MODULE,
	125	.encap = XFRM_MODE_TUNNEL,
	126	};
	127
	128	static int __init xfrm6_tunnel_init(void)
	129	{
	130	return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
	131	}
	132
	133	static void __exit xfrm6_tunnel_exit(void)
	134	{
	135	int err;
	136
	137	err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
	138	BUG_ON(err);
	139	}
	140
	141	module_init(xfrm6_tunnel_init);
	142	module_exit(xfrm6_tunnel_exit);
	143	MODULE_LICENSE("GPL");
	144	MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);