[GitHub/mt8127/android_kernel_alcatel_ttab.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>

/* Informational hook. The decap is still done here. */
static struct xfrm_tunnel __rcu *rcv_notify_handlers __read_mostly;
static DEFINE_MUTEX(xfrm4_mode_tunnel_input_mutex);

int xfrm4_mode_tunnel_input_register(struct xfrm_tunnel *handler)
{
	struct xfrm_tunnel __rcu **pprev;
	struct xfrm_tunnel *t;
	int ret = -EEXIST;
	int priority = handler->priority;

	mutex_lock(&xfrm4_mode_tunnel_input_mutex);

	for (pprev = &rcv_notify_handlers;
	     (t = rcu_dereference_protected(*pprev,
	     lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL;
	     pprev = &t->next) {
		if (t->priority > priority)
			break;
		if (t->priority == priority)
			goto err;

	}

	handler->next = *pprev;
	rcu_assign_pointer(*pprev, handler);

	ret = 0;

err:
	mutex_unlock(&xfrm4_mode_tunnel_input_mutex);
	return ret;
}
EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_register);

int xfrm4_mode_tunnel_input_deregister(struct xfrm_tunnel *handler)
{
	struct xfrm_tunnel __rcu **pprev;
	struct xfrm_tunnel *t;
	int ret = -ENOENT;

	mutex_lock(&xfrm4_mode_tunnel_input_mutex);
	for (pprev = &rcv_notify_handlers;
	     (t = rcu_dereference_protected(*pprev,
	     lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL;
	     pprev = &t->next) {
		if (t == handler) {
			*pprev = handler->next;
			ret = 0;
			break;
		}
	}
	mutex_unlock(&xfrm4_mode_tunnel_input_mutex);
	synchronize_net();

	return ret;
}
EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_deregister);

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(skb, NULL);

	return 0;
}

#define for_each_input_rcu(head, handler)	\
	for (handler = rcu_dereference(head);	\
	     handler != NULL;			\
	     handler = rcu_dereference(handler->next))

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

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

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

	for_each_input_rcu(rcv_notify_handlers, handler)
		handler->handler(skb);

	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
eb8637cd S	18	/* Informational hook. The decap is still done here. */
	19	static struct xfrm_tunnel __rcu *rcv_notify_handlers __read_mostly;
	20	static DEFINE_MUTEX(xfrm4_mode_tunnel_input_mutex);
	21
	22	int xfrm4_mode_tunnel_input_register(struct xfrm_tunnel *handler)
	23	{
	24	struct xfrm_tunnel __rcu **pprev;
	25	struct xfrm_tunnel *t;
	26	int ret = -EEXIST;
	27	int priority = handler->priority;
	28
	29	mutex_lock(&xfrm4_mode_tunnel_input_mutex);
	30
	31	for (pprev = &rcv_notify_handlers;
	32	(t = rcu_dereference_protected(*pprev,
	33	lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL;
	34	pprev = &t->next) {
	35	if (t->priority > priority)
	36	break;
	37	if (t->priority == priority)
	38	goto err;
	39
	40	}
	41
	42	handler->next = *pprev;
	43	rcu_assign_pointer(*pprev, handler);
	44
	45	ret = 0;
	46
	47	err:
	48	mutex_unlock(&xfrm4_mode_tunnel_input_mutex);
	49	return ret;
	50	}
	51	EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_register);
	52
	53	int xfrm4_mode_tunnel_input_deregister(struct xfrm_tunnel *handler)
	54	{
	55	struct xfrm_tunnel __rcu **pprev;
	56	struct xfrm_tunnel *t;
	57	int ret = -ENOENT;
	58
	59	mutex_lock(&xfrm4_mode_tunnel_input_mutex);
	60	for (pprev = &rcv_notify_handlers;
	61	(t = rcu_dereference_protected(*pprev,
	62	lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL;
	63	pprev = &t->next) {
	64	if (t == handler) {
	65	*pprev = handler->next;
	66	ret = 0;
	67	break;
	68	}
	69	}
	70	mutex_unlock(&xfrm4_mode_tunnel_input_mutex);
	71	synchronize_net();
	72
	73	return ret;
	74	}
	75	EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_deregister);
	76
b59f45d0 HX	77	static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
b59f45d0 HX	78	{
b0061ce4	79	struct iphdr *inner_iph = ipip_hdr(skb);
b59f45d0	80
227620e2	81	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
b59f45d0 HX	82	IP_ECN_set_ce(inner_iph);
	83	}
	84
	85	/* Add encapsulation header.
	86	*
ceb1eec8	87	* The top IP header will be constructed per RFC 2401.
b59f45d0	88	*/
195ad6a3	89	static int xfrm4_mode_tunnel_output(struct xfrm_state x, struct sk_buff skb)
b59f45d0	90	{
adf30907	91	struct dst_entry *dst = skb_dst(skb);
36cf9acf	92	struct iphdr *top_iph;
b59f45d0 HX	93	int flags;
b59f45d0 HX	94
7b277b1a	95	skb_set_network_header(skb, -x->props.header_len);
37fedd3a HX	96	skb->mac_header = skb->network_header +
37fedd3a HX	97	offsetof(struct iphdr, protocol);
36cf9acf	98	skb->transport_header = skb->network_header + sizeof(*top_iph);
eddc9ec5	99	top_iph = ip_hdr(skb);
b59f45d0 HX	100
	101	top_iph->ihl = 5;
	102	top_iph->version = 4;
	103
adf30907	104	top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
c82f963e	105
a947b0a9 ND	106	/* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
	107	if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
	108	top_iph->tos = 0;
	109	else
	110	top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
	111	top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
36cf9acf	112	XFRM_MODE_SKB_CB(skb)->tos);
b59f45d0	113
36cf9acf	114	flags = x->props.flags;
b59f45d0 HX	115	if (flags & XFRM_STATE_NOECN)
	116	IP_ECN_clear(top_iph);
	117
36cf9acf	118	top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
fe833fca	119	0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
b59f45d0	120
323e126f	121	top_iph->ttl = ip4_dst_hoplimit(dst->child);
b59f45d0 HX	122
	123	top_iph->saddr = x->props.saddr.a4;
	124	top_iph->daddr = x->id.daddr.a4;
ff1f69a8	125	ip_select_ident(skb, NULL);
b59f45d0	126
b59f45d0 HX	127	return 0;
	128	}
	129
eb8637cd S	130	#define for_each_input_rcu(head, handler) \
	131	for (handler = rcu_dereference(head); \
	132	handler != NULL; \
	133	handler = rcu_dereference(handler->next))
	134
195ad6a3	135	static int xfrm4_mode_tunnel_input(struct xfrm_state x, struct sk_buff skb)
b59f45d0	136	{
eb8637cd	137	struct xfrm_tunnel *handler;
b59f45d0 HX	138	int err = -EINVAL;
b59f45d0 HX	139
227620e2 HX	140	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
227620e2 HX	141	goto out;
c82f963e	142
b59f45d0 HX	143	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	144	goto out;
	145
eb8637cd S	146	for_each_input_rcu(rcv_notify_handlers, handler)
	147	handler->handler(skb);
	148
9aac22de	149	err = skb_unclone(skb, GFP_ATOMIC);
9aac22de	150	if (err)
b59f45d0 HX	151	goto out;
b59f45d0 HX	152
227620e2 HX	153	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
	154	ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
	155	if (!(x->props.flags & XFRM_STATE_NOECN))
	156	ipip_ecn_decapsulate(skb);
	157
c1d2bbe1	158	skb_reset_network_header(skb);
03606895 ED	159	skb_mac_header_rebuild(skb);
03606895 ED	160
b59f45d0 HX	161	err = 0;
	162
	163	out:
	164	return err;
	165	}
	166
	167	static struct xfrm_mode xfrm4_tunnel_mode = {
195ad6a3	168	.input2 = xfrm4_mode_tunnel_input,
227620e2	169	.input = xfrm_prepare_input,
195ad6a3	170	.output2 = xfrm4_mode_tunnel_output,
36cf9acf	171	.output = xfrm4_prepare_output,
b59f45d0 HX	172	.owner = THIS_MODULE,
b59f45d0 HX	173	.encap = XFRM_MODE_TUNNEL,
1bfcb10f	174	.flags = XFRM_MODE_FLAG_TUNNEL,
b59f45d0 HX	175	};
b59f45d0 HX	176
195ad6a3	177	static int __init xfrm4_mode_tunnel_init(void)
b59f45d0 HX	178	{
	179	return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
	180	}
	181
195ad6a3	182	static void __exit xfrm4_mode_tunnel_exit(void)
b59f45d0 HX	183	{
	184	int err;
	185
	186	err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
	187	BUG_ON(err);
	188	}
	189
195ad6a3 HX	190	module_init(xfrm4_mode_tunnel_init);
195ad6a3 HX	191	module_exit(xfrm4_mode_tunnel_exit);
b59f45d0 HX	192	MODULE_LICENSE("GPL");
b59f45d0 HX	193	MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);