[GitHub/exynos8895/android_kernel_samsung_universal8895.git] / net / ipv4 / gre_demux.c

/*
 *	GRE over IPv4 demultiplexer driver
 *
 *	Authors: Dmitry Kozlov (xeb@mail.ru)
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/if.h>
#include <linux/icmp.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/netdevice.h>
#include <linux/if_tunnel.h>
#include <linux/spinlock.h>
#include <net/protocol.h>
#include <net/gre.h>

#include <net/icmp.h>
#include <net/route.h>
#include <net/xfrm.h>

static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;

int gre_add_protocol(const struct gre_protocol *proto, u8 version)
{
	if (version >= GREPROTO_MAX)
		return -EINVAL;

	return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
		0 : -EBUSY;
}
EXPORT_SYMBOL_GPL(gre_add_protocol);

int gre_del_protocol(const struct gre_protocol *proto, u8 version)
{
	int ret;

	if (version >= GREPROTO_MAX)
		return -EINVAL;

	ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
		0 : -EBUSY;

	if (ret)
		return ret;

	synchronize_rcu();
	return 0;
}
EXPORT_SYMBOL_GPL(gre_del_protocol);

static int gre_rcv(struct sk_buff *skb)
{
	const struct gre_protocol *proto;
	u8 ver;
	int ret;

	if (!pskb_may_pull(skb, 12))
		goto drop;

	ver = skb->data[1]&0x7f;
	if (ver >= GREPROTO_MAX)
		goto drop;

	rcu_read_lock();
	proto = rcu_dereference(gre_proto[ver]);
	if (!proto || !proto->handler)
		goto drop_unlock;
	ret = proto->handler(skb);
	rcu_read_unlock();
	return ret;

drop_unlock:
	rcu_read_unlock();
drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static void gre_err(struct sk_buff *skb, u32 info)
{
	const struct gre_protocol *proto;
	const struct iphdr *iph = (const struct iphdr *)skb->data;
	u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;

	if (ver >= GREPROTO_MAX)
		return;

	rcu_read_lock();
	proto = rcu_dereference(gre_proto[ver]);
	if (proto && proto->err_handler)
		proto->err_handler(skb, info);
	rcu_read_unlock();
}

static const struct net_protocol net_gre_protocol = {
	.handler     = gre_rcv,
	.err_handler = gre_err,
	.netns_ok    = 1,
};

static int __init gre_init(void)
{
	pr_info("GRE over IPv4 demultiplexor driver\n");

	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
		pr_err("can't add protocol\n");
		return -EAGAIN;
	}
	return 0;
}

static void __exit gre_exit(void)
{
	inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
}

module_init(gre_init);
module_exit(gre_exit);

MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver");
MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
MODULE_LICENSE("GPL");
Commit	Line	Data
00959ade DK	1	/*
	2	* GRE over IPv4 demultiplexer driver
	3	*
	4	* Authors: Dmitry Kozlov (xeb@mail.ru)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*
	11	*/
	12
afd46503 JP	13	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
afd46503 JP	14
00959ade	15	#include <linux/module.h>
bda7bb46 PS	16	#include <linux/if.h>
bda7bb46 PS	17	#include <linux/icmp.h>
00959ade DK	18	#include <linux/kernel.h>
	19	#include <linux/kmod.h>
	20	#include <linux/skbuff.h>
	21	#include <linux/in.h>
559fafb9	22	#include <linux/ip.h>
00959ade	23	#include <linux/netdevice.h>
68c33163	24	#include <linux/if_tunnel.h>
00959ade DK	25	#include <linux/spinlock.h>
	26	#include <net/protocol.h>
	27	#include <net/gre.h>
	28
bda7bb46 PS	29	#include <net/icmp.h>
	30	#include <net/route.h>
	31	#include <net/xfrm.h>
00959ade	32
6f0bcf15	33	static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
00959ade DK	34
	35	int gre_add_protocol(const struct gre_protocol *proto, u8 version)
	36	{
	37	if (version >= GREPROTO_MAX)
20fd4d1f	38	return -EINVAL;
00959ade	39
20fd4d1f PS	40	return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
20fd4d1f PS	41	0 : -EBUSY;
00959ade DK	42	}
	43	EXPORT_SYMBOL_GPL(gre_add_protocol);
	44
	45	int gre_del_protocol(const struct gre_protocol *proto, u8 version)
	46	{
20fd4d1f PS	47	int ret;
20fd4d1f PS	48
00959ade	49	if (version >= GREPROTO_MAX)
20fd4d1f PS	50	return -EINVAL;
	51
	52	ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
	53	0 : -EBUSY;
	54
	55	if (ret)
	56	return ret;
	57
00959ade DK	58	synchronize_rcu();
00959ade DK	59	return 0;
00959ade DK	60	}
	61	EXPORT_SYMBOL_GPL(gre_del_protocol);
	62
	63	static int gre_rcv(struct sk_buff *skb)
	64	{
	65	const struct gre_protocol *proto;
	66	u8 ver;
	67	int ret;
	68
	69	if (!pskb_may_pull(skb, 12))
	70	goto drop;
	71
	72	ver = skb->data[1]&0x7f;
	73	if (ver >= GREPROTO_MAX)
	74	goto drop;
	75
	76	rcu_read_lock();
	77	proto = rcu_dereference(gre_proto[ver]);
	78	if (!proto \|\| !proto->handler)
	79	goto drop_unlock;
	80	ret = proto->handler(skb);
	81	rcu_read_unlock();
	82	return ret;
	83
	84	drop_unlock:
	85	rcu_read_unlock();
	86	drop:
	87	kfree_skb(skb);
	88	return NET_RX_DROP;
	89	}
	90
	91	static void gre_err(struct sk_buff *skb, u32 info)
	92	{
	93	const struct gre_protocol *proto;
559fafb9	94	const struct iphdr iph = (const struct iphdr )skb->data;
559fafb9	95	u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
00959ade	96
00959ade	97	if (ver >= GREPROTO_MAX)
559fafb9	98	return;
00959ade DK	99
	100	rcu_read_lock();
	101	proto = rcu_dereference(gre_proto[ver]);
559fafb9	102	if (proto && proto->err_handler)
559fafb9	103	proto->err_handler(skb, info);
00959ade	104	rcu_read_unlock();
00959ade DK	105	}
	106
	107	static const struct net_protocol net_gre_protocol = {
	108	.handler = gre_rcv,
	109	.err_handler = gre_err,
	110	.netns_ok = 1,
	111	};
	112
	113	static int __init gre_init(void)
	114	{
afd46503	115	pr_info("GRE over IPv4 demultiplexor driver\n");
00959ade DK	116
00959ade DK	117	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
afd46503	118	pr_err("can't add protocol\n");
9f57c67c	119	return -EAGAIN;
bda7bb46	120	}
00959ade DK	121	return 0;
	122	}
	123
	124	static void __exit gre_exit(void)
	125	{
	126	inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
	127	}
	128
	129	module_init(gre_init);
	130	module_exit(gre_exit);
	131
	132	MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver");
	133	MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
	134	MODULE_LICENSE("GPL");