Git Repo - linux.git/blame_incremental

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Commit	Line	Data
	1	/*
	2	* GRE over IPv4 demultiplexer driver
	3	*
	4	* Authors: Dmitry Kozlov ([email protected])
	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
	13	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	14
	15	#include <linux/module.h>
	16	#include <linux/if.h>
	17	#include <linux/icmp.h>
	18	#include <linux/kernel.h>
	19	#include <linux/kmod.h>
	20	#include <linux/skbuff.h>
	21	#include <linux/in.h>
	22	#include <linux/ip.h>
	23	#include <linux/netdevice.h>
	24	#include <linux/if_tunnel.h>
	25	#include <linux/spinlock.h>
	26	#include <net/protocol.h>
	27	#include <net/gre.h>
	28
	29	#include <net/icmp.h>
	30	#include <net/route.h>
	31	#include <net/xfrm.h>
	32
	33	static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
	34
	35	int gre_add_protocol(const struct gre_protocol *proto, u8 version)
	36	{
	37	if (version >= GREPROTO_MAX)
	38	return -EINVAL;
	39
	40	return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
	41	0 : -EBUSY;
	42	}
	43	EXPORT_SYMBOL_GPL(gre_add_protocol);
	44
	45	int gre_del_protocol(const struct gre_protocol *proto, u8 version)
	46	{
	47	int ret;
	48
	49	if (version >= GREPROTO_MAX)
	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
	58	synchronize_rcu();
	59	return 0;
	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;
	94	const struct iphdr iph = (const struct iphdr )skb->data;
	95	u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
	96
	97	if (ver >= GREPROTO_MAX)
	98	return;
	99
	100	rcu_read_lock();
	101	proto = rcu_dereference(gre_proto[ver]);
	102	if (proto && proto->err_handler)
	103	proto->err_handler(skb, info);
	104	rcu_read_unlock();
	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	{
	115	pr_info("GRE over IPv4 demultiplexor driver\n");
	116
	117	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
	118	pr_err("can't add protocol\n");
	119	return -EAGAIN;
	120	}
	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 ([email protected])");
	134	MODULE_LICENSE("GPL");