[deliverable/linux.git] / net / ipv6 / netfilter / ip6table_mangle.c

/*
 * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6
 *
 * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/netfilter_ipv6/ip6_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("ip6tables mangle table");

#define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
			    (1 << NF_INET_LOCAL_IN) | \
			    (1 << NF_INET_FORWARD) | \
			    (1 << NF_INET_LOCAL_OUT) | \
			    (1 << NF_INET_POST_ROUTING))

static struct
{
	struct ip6t_replace repl;
	struct ip6t_standard entries[5];
	struct ip6t_error term;
} initial_table __net_initdata = {
	.repl = {
		.name = "mangle",
		.valid_hooks = MANGLE_VALID_HOOKS,
		.num_entries = 6,
		.size = sizeof(struct ip6t_standard) * 5 + sizeof(struct ip6t_error),
		.hook_entry = {
			[NF_INET_PRE_ROUTING] 	= 0,
			[NF_INET_LOCAL_IN]	= sizeof(struct ip6t_standard),
			[NF_INET_FORWARD]	= sizeof(struct ip6t_standard) * 2,
			[NF_INET_LOCAL_OUT] 	= sizeof(struct ip6t_standard) * 3,
			[NF_INET_POST_ROUTING]	= sizeof(struct ip6t_standard) * 4,
		},
		.underflow = {
			[NF_INET_PRE_ROUTING] 	= 0,
			[NF_INET_LOCAL_IN]	= sizeof(struct ip6t_standard),
			[NF_INET_FORWARD]	= sizeof(struct ip6t_standard) * 2,
			[NF_INET_LOCAL_OUT] 	= sizeof(struct ip6t_standard) * 3,
			[NF_INET_POST_ROUTING]	= sizeof(struct ip6t_standard) * 4,
		},
	},
	.entries = {
		IP6T_STANDARD_INIT(NF_ACCEPT),	/* PRE_ROUTING */
		IP6T_STANDARD_INIT(NF_ACCEPT),	/* LOCAL_IN */
		IP6T_STANDARD_INIT(NF_ACCEPT),	/* FORWARD */
		IP6T_STANDARD_INIT(NF_ACCEPT),	/* LOCAL_OUT */
		IP6T_STANDARD_INIT(NF_ACCEPT),	/* POST_ROUTING */
	},
	.term = IP6T_ERROR_INIT,		/* ERROR */
};

static struct xt_table packet_mangler = {
	.name		= "mangle",
	.valid_hooks	= MANGLE_VALID_HOOKS,
	.lock		= __RW_LOCK_UNLOCKED(packet_mangler.lock),
	.me		= THIS_MODULE,
	.af		= AF_INET6,
};

/* The work comes in here from netfilter.c. */
static unsigned int
ip6t_in_hook(unsigned int hook,
	 struct sk_buff *skb,
	 const struct net_device *in,
	 const struct net_device *out,
	 int (*okfn)(struct sk_buff *))
{
	return ip6t_do_table(skb, hook, in, out,
			     dev_net(in)->ipv6.ip6table_mangle);
}

static unsigned int
ip6t_post_routing_hook(unsigned int hook,
		struct sk_buff *skb,
		const struct net_device *in,
		const struct net_device *out,
		int (*okfn)(struct sk_buff *))
{
	return ip6t_do_table(skb, hook, in, out,
			     dev_net(out)->ipv6.ip6table_mangle);
}

static unsigned int
ip6t_local_out_hook(unsigned int hook,
		   struct sk_buff *skb,
		   const struct net_device *in,
		   const struct net_device *out,
		   int (*okfn)(struct sk_buff *))
{

	unsigned int ret;
	struct in6_addr saddr, daddr;
	u_int8_t hop_limit;
	u_int32_t flowlabel, mark;

#if 0
	/* root is playing with raw sockets. */
	if (skb->len < sizeof(struct iphdr)
	    || ip_hdrlen(skb) < sizeof(struct iphdr)) {
		if (net_ratelimit())
			printk("ip6t_hook: happy cracking.\n");
		return NF_ACCEPT;
	}
#endif

	/* save source/dest address, mark, hoplimit, flowlabel, priority,  */
	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
	mark = skb->mark;
	hop_limit = ipv6_hdr(skb)->hop_limit;

	/* flowlabel and prio (includes version, which shouldn't change either */
	flowlabel = *((u_int32_t *)ipv6_hdr(skb));

	ret = ip6t_do_table(skb, hook, in, out,
			    dev_net(out)->ipv6.ip6table_mangle);

	if (ret != NF_DROP && ret != NF_STOLEN
		&& (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr))
		    || memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr))
		    || skb->mark != mark
		    || ipv6_hdr(skb)->hop_limit != hop_limit))
		return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;

	return ret;
}

static struct nf_hook_ops ip6t_ops[] __read_mostly = {
	{
		.hook		= ip6t_in_hook,
		.owner		= THIS_MODULE,
		.pf		= PF_INET6,
		.hooknum	= NF_INET_PRE_ROUTING,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_in_hook,
		.owner		= THIS_MODULE,
		.pf		= PF_INET6,
		.hooknum	= NF_INET_LOCAL_IN,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_in_hook,
		.owner		= THIS_MODULE,
		.pf		= PF_INET6,
		.hooknum	= NF_INET_FORWARD,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_local_out_hook,
		.owner		= THIS_MODULE,
		.pf		= PF_INET6,
		.hooknum	= NF_INET_LOCAL_OUT,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_post_routing_hook,
		.owner		= THIS_MODULE,
		.pf		= PF_INET6,
		.hooknum	= NF_INET_POST_ROUTING,
		.priority	= NF_IP6_PRI_MANGLE,
	},
};

static int __net_init ip6table_mangle_net_init(struct net *net)
{
	/* Register table */
	net->ipv6.ip6table_mangle =
		ip6t_register_table(net, &packet_mangler, &initial_table.repl);
	if (IS_ERR(net->ipv6.ip6table_mangle))
		return PTR_ERR(net->ipv6.ip6table_mangle);
	return 0;
}

static void __net_exit ip6table_mangle_net_exit(struct net *net)
{
	ip6t_unregister_table(net->ipv6.ip6table_mangle);
}

static struct pernet_operations ip6table_mangle_net_ops = {
	.init = ip6table_mangle_net_init,
	.exit = ip6table_mangle_net_exit,
};

static int __init ip6table_mangle_init(void)
{
	int ret;

	ret = register_pernet_subsys(&ip6table_mangle_net_ops);
	if (ret < 0)
		return ret;

	/* Register hooks */
	ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
	if (ret < 0)
		goto cleanup_table;

	return ret;

 cleanup_table:
	unregister_pernet_subsys(&ip6table_mangle_net_ops);
	return ret;
}

static void __exit ip6table_mangle_fini(void)
{
	nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
	unregister_pernet_subsys(&ip6table_mangle_net_ops);
}

module_init(ip6table_mangle_init);
module_exit(ip6table_mangle_fini);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6
	3	*
	4	* Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
	5	* Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
1da177e4 LT	10	*/
	11	#include <linux/module.h>
	12	#include <linux/netfilter_ipv6/ip6_tables.h>
	13
	14	MODULE_LICENSE("GPL");
	15	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	16	MODULE_DESCRIPTION("ip6tables mangle table");
	17
6e23ae2a PM	18	#define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) \| \
	19	(1 << NF_INET_LOCAL_IN) \| \
	20	(1 << NF_INET_FORWARD) \| \
	21	(1 << NF_INET_LOCAL_OUT) \| \
	22	(1 << NF_INET_POST_ROUTING))
1da177e4	23
1da177e4 LT	24	static struct
	25	{
	26	struct ip6t_replace repl;
	27	struct ip6t_standard entries[5];
	28	struct ip6t_error term;
8280aa61	29	} initial_table __net_initdata = {
3c2ad469 PM	30	.repl = {
	31	.name = "mangle",
	32	.valid_hooks = MANGLE_VALID_HOOKS,
	33	.num_entries = 6,
	34	.size = sizeof(struct ip6t_standard) * 5 + sizeof(struct ip6t_error),
	35	.hook_entry = {
6e23ae2a PM	36	[NF_INET_PRE_ROUTING] = 0,
	37	[NF_INET_LOCAL_IN] = sizeof(struct ip6t_standard),
	38	[NF_INET_FORWARD] = sizeof(struct ip6t_standard) * 2,
	39	[NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3,
	40	[NF_INET_POST_ROUTING] = sizeof(struct ip6t_standard) * 4,
3c2ad469 PM	41	},
3c2ad469 PM	42	.underflow = {
6e23ae2a PM	43	[NF_INET_PRE_ROUTING] = 0,
	44	[NF_INET_LOCAL_IN] = sizeof(struct ip6t_standard),
	45	[NF_INET_FORWARD] = sizeof(struct ip6t_standard) * 2,
	46	[NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3,
	47	[NF_INET_POST_ROUTING] = sizeof(struct ip6t_standard) * 4,
3c2ad469 PM	48	},
	49	},
	50	.entries = {
	51	IP6T_STANDARD_INIT(NF_ACCEPT), /* PRE_ROUTING */
	52	IP6T_STANDARD_INIT(NF_ACCEPT), /* LOCAL_IN */
	53	IP6T_STANDARD_INIT(NF_ACCEPT), /* FORWARD */
	54	IP6T_STANDARD_INIT(NF_ACCEPT), /* LOCAL_OUT */
	55	IP6T_STANDARD_INIT(NF_ACCEPT), /* POST_ROUTING */
	56	},
	57	.term = IP6T_ERROR_INIT, /* ERROR */
1da177e4 LT	58	};
1da177e4 LT	59
8280aa61	60	static struct xt_table packet_mangler = {
1da177e4 LT	61	.name = "mangle",
1da177e4 LT	62	.valid_hooks = MANGLE_VALID_HOOKS,
fdccecd0	63	.lock = __RW_LOCK_UNLOCKED(packet_mangler.lock),
1da177e4	64	.me = THIS_MODULE,
2e4e6a17	65	.af = AF_INET6,
1da177e4 LT	66	};
	67
	68	/* The work comes in here from netfilter.c. */
	69	static unsigned int
7dd1b8da	70	ip6t_in_hook(unsigned int hook,
3db05fea	71	struct sk_buff *skb,
1da177e4 LT	72	const struct net_device *in,
	73	const struct net_device *out,
	74	int (okfn)(struct sk_buff ))
	75	{
7dd1b8da AD	76	return ip6t_do_table(skb, hook, in, out,
7dd1b8da AD	77	dev_net(in)->ipv6.ip6table_mangle);
1da177e4 LT	78	}
	79
	80	static unsigned int
7dd1b8da AD	81	ip6t_post_routing_hook(unsigned int hook,
	82	struct sk_buff *skb,
	83	const struct net_device *in,
	84	const struct net_device *out,
	85	int (okfn)(struct sk_buff ))
	86	{
	87	return ip6t_do_table(skb, hook, in, out,
	88	dev_net(out)->ipv6.ip6table_mangle);
	89	}
	90
	91	static unsigned int
	92	ip6t_local_out_hook(unsigned int hook,
3db05fea	93	struct sk_buff *skb,
1da177e4 LT	94	const struct net_device *in,
	95	const struct net_device *out,
	96	int (okfn)(struct sk_buff ))
	97	{
	98
1da177e4 LT	99	unsigned int ret;
	100	struct in6_addr saddr, daddr;
	101	u_int8_t hop_limit;
82e91ffe	102	u_int32_t flowlabel, mark;
1da177e4 LT	103
	104	#if 0
	105	/* root is playing with raw sockets. */
3db05fea HX	106	if (skb->len < sizeof(struct iphdr)
3db05fea HX	107	\|\| ip_hdrlen(skb) < sizeof(struct iphdr)) {
1da177e4 LT	108	if (net_ratelimit())
	109	printk("ip6t_hook: happy cracking.\n");
	110	return NF_ACCEPT;
	111	}
	112	#endif
	113
82e91ffe	114	/* save source/dest address, mark, hoplimit, flowlabel, priority, */
3db05fea HX	115	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
	116	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
	117	mark = skb->mark;
	118	hop_limit = ipv6_hdr(skb)->hop_limit;
1da177e4 LT	119
1da177e4 LT	120	/* flowlabel and prio (includes version, which shouldn't change either */
3db05fea	121	flowlabel = ((u_int32_t )ipv6_hdr(skb));
1da177e4	122
7dd1b8da AD	123	ret = ip6t_do_table(skb, hook, in, out,
7dd1b8da AD	124	dev_net(out)->ipv6.ip6table_mangle);
1da177e4	125
1ab1457c	126	if (ret != NF_DROP && ret != NF_STOLEN
3db05fea HX	127	&& (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr))
	128	\|\| memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr))
	129	\|\| skb->mark != mark
	130	\|\| ipv6_hdr(skb)->hop_limit != hop_limit))
	131	return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
1da177e4 LT	132
	133	return ret;
	134	}
	135
1999414a	136	static struct nf_hook_ops ip6t_ops[] __read_mostly = {
1da177e4	137	{
7dd1b8da	138	.hook = ip6t_in_hook,
1da177e4 LT	139	.owner = THIS_MODULE,
1da177e4 LT	140	.pf = PF_INET6,
6e23ae2a	141	.hooknum = NF_INET_PRE_ROUTING,
1da177e4 LT	142	.priority = NF_IP6_PRI_MANGLE,
	143	},
	144	{
7dd1b8da	145	.hook = ip6t_in_hook,
1da177e4 LT	146	.owner = THIS_MODULE,
1da177e4 LT	147	.pf = PF_INET6,
6e23ae2a	148	.hooknum = NF_INET_LOCAL_IN,
1da177e4 LT	149	.priority = NF_IP6_PRI_MANGLE,
	150	},
	151	{
7dd1b8da	152	.hook = ip6t_in_hook,
1da177e4 LT	153	.owner = THIS_MODULE,
1da177e4 LT	154	.pf = PF_INET6,
6e23ae2a	155	.hooknum = NF_INET_FORWARD,
1da177e4 LT	156	.priority = NF_IP6_PRI_MANGLE,
	157	},
	158	{
7dd1b8da	159	.hook = ip6t_local_out_hook,
1da177e4 LT	160	.owner = THIS_MODULE,
1da177e4 LT	161	.pf = PF_INET6,
6e23ae2a	162	.hooknum = NF_INET_LOCAL_OUT,
1da177e4 LT	163	.priority = NF_IP6_PRI_MANGLE,
	164	},
	165	{
7dd1b8da	166	.hook = ip6t_post_routing_hook,
1da177e4 LT	167	.owner = THIS_MODULE,
1da177e4 LT	168	.pf = PF_INET6,
6e23ae2a	169	.hooknum = NF_INET_POST_ROUTING,
1da177e4 LT	170	.priority = NF_IP6_PRI_MANGLE,
	171	},
	172	};
	173
8280aa61 AD	174	static int __net_init ip6table_mangle_net_init(struct net *net)
	175	{
	176	/* Register table */
	177	net->ipv6.ip6table_mangle =
	178	ip6t_register_table(net, &packet_mangler, &initial_table.repl);
	179	if (IS_ERR(net->ipv6.ip6table_mangle))
	180	return PTR_ERR(net->ipv6.ip6table_mangle);
	181	return 0;
	182	}
	183
	184	static void __net_exit ip6table_mangle_net_exit(struct net *net)
	185	{
	186	ip6t_unregister_table(net->ipv6.ip6table_mangle);
	187	}
	188
	189	static struct pernet_operations ip6table_mangle_net_ops = {
	190	.init = ip6table_mangle_net_init,
	191	.exit = ip6table_mangle_net_exit,
	192	};
	193
65b4b4e8	194	static int __init ip6table_mangle_init(void)
1da177e4 LT	195	{
	196	int ret;
	197
8280aa61 AD	198	ret = register_pernet_subsys(&ip6table_mangle_net_ops);
	199	if (ret < 0)
	200	return ret;
1da177e4 LT	201
1da177e4 LT	202	/* Register hooks */
964ddaa1	203	ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
1da177e4 LT	204	if (ret < 0)
	205	goto cleanup_table;
	206
1da177e4 LT	207	return ret;
1da177e4 LT	208
1da177e4	209	cleanup_table:
8280aa61	210	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	211	return ret;
	212	}
	213
65b4b4e8	214	static void __exit ip6table_mangle_fini(void)
1da177e4	215	{
964ddaa1	216	nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
8280aa61	217	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	218	}
1da177e4 LT	219
65b4b4e8 AM	220	module_init(ip6table_mangle_init);
65b4b4e8 AM	221	module_exit(ip6table_mangle_fini);