[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 const 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 const struct xt_table packet_mangler = {
	.name		= "mangle",
	.valid_hooks	= MANGLE_VALID_HOOKS,
	.me		= THIS_MODULE,
	.af		= NFPROTO_IPV6,
};

/* 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		= NFPROTO_IPV6,
		.hooknum	= NF_INET_PRE_ROUTING,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_in_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.hooknum	= NF_INET_LOCAL_IN,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_in_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.hooknum	= NF_INET_FORWARD,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_local_out_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.hooknum	= NF_INET_LOCAL_OUT,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6t_post_routing_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.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
35aad0ff	24	static const struct
1da177e4 LT	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
35aad0ff	60	static const struct xt_table packet_mangler = {
1da177e4 LT	61	.name = "mangle",
1da177e4 LT	62	.valid_hooks = MANGLE_VALID_HOOKS,
1da177e4	63	.me = THIS_MODULE,
f88e6a8a	64	.af = NFPROTO_IPV6,
1da177e4 LT	65	};
	66
	67	/* The work comes in here from netfilter.c. */
	68	static unsigned int
7dd1b8da	69	ip6t_in_hook(unsigned int hook,
3db05fea	70	struct sk_buff *skb,
1da177e4 LT	71	const struct net_device *in,
	72	const struct net_device *out,
	73	int (okfn)(struct sk_buff ))
	74	{
7dd1b8da AD	75	return ip6t_do_table(skb, hook, in, out,
7dd1b8da AD	76	dev_net(in)->ipv6.ip6table_mangle);
1da177e4 LT	77	}
	78
	79	static unsigned int
7dd1b8da AD	80	ip6t_post_routing_hook(unsigned int hook,
	81	struct sk_buff *skb,
	82	const struct net_device *in,
	83	const struct net_device *out,
	84	int (okfn)(struct sk_buff ))
	85	{
	86	return ip6t_do_table(skb, hook, in, out,
	87	dev_net(out)->ipv6.ip6table_mangle);
	88	}
	89
	90	static unsigned int
	91	ip6t_local_out_hook(unsigned int hook,
3db05fea	92	struct sk_buff *skb,
1da177e4 LT	93	const struct net_device *in,
	94	const struct net_device *out,
	95	int (okfn)(struct sk_buff ))
	96	{
	97
1da177e4 LT	98	unsigned int ret;
	99	struct in6_addr saddr, daddr;
	100	u_int8_t hop_limit;
82e91ffe	101	u_int32_t flowlabel, mark;
1da177e4 LT	102
	103	#if 0
	104	/* root is playing with raw sockets. */
3db05fea HX	105	if (skb->len < sizeof(struct iphdr)
3db05fea HX	106	\|\| ip_hdrlen(skb) < sizeof(struct iphdr)) {
1da177e4 LT	107	if (net_ratelimit())
	108	printk("ip6t_hook: happy cracking.\n");
	109	return NF_ACCEPT;
	110	}
	111	#endif
	112
82e91ffe	113	/* save source/dest address, mark, hoplimit, flowlabel, priority, */
3db05fea HX	114	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
	115	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
	116	mark = skb->mark;
	117	hop_limit = ipv6_hdr(skb)->hop_limit;
1da177e4 LT	118
1da177e4 LT	119	/* flowlabel and prio (includes version, which shouldn't change either */
3db05fea	120	flowlabel = ((u_int32_t )ipv6_hdr(skb));
1da177e4	121
7dd1b8da AD	122	ret = ip6t_do_table(skb, hook, in, out,
7dd1b8da AD	123	dev_net(out)->ipv6.ip6table_mangle);
1da177e4	124
1ab1457c	125	if (ret != NF_DROP && ret != NF_STOLEN
3db05fea HX	126	&& (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr))
	127	\|\| memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr))
	128	\|\| skb->mark != mark
	129	\|\| ipv6_hdr(skb)->hop_limit != hop_limit))
	130	return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
1da177e4 LT	131
	132	return ret;
	133	}
	134
1999414a	135	static struct nf_hook_ops ip6t_ops[] __read_mostly = {
1da177e4	136	{
7dd1b8da	137	.hook = ip6t_in_hook,
1da177e4	138	.owner = THIS_MODULE,
24c232d8	139	.pf = NFPROTO_IPV6,
6e23ae2a	140	.hooknum = NF_INET_PRE_ROUTING,
1da177e4 LT	141	.priority = NF_IP6_PRI_MANGLE,
	142	},
	143	{
7dd1b8da	144	.hook = ip6t_in_hook,
1da177e4	145	.owner = THIS_MODULE,
24c232d8	146	.pf = NFPROTO_IPV6,
6e23ae2a	147	.hooknum = NF_INET_LOCAL_IN,
1da177e4 LT	148	.priority = NF_IP6_PRI_MANGLE,
	149	},
	150	{
7dd1b8da	151	.hook = ip6t_in_hook,
1da177e4	152	.owner = THIS_MODULE,
24c232d8	153	.pf = NFPROTO_IPV6,
6e23ae2a	154	.hooknum = NF_INET_FORWARD,
1da177e4 LT	155	.priority = NF_IP6_PRI_MANGLE,
	156	},
	157	{
7dd1b8da	158	.hook = ip6t_local_out_hook,
1da177e4	159	.owner = THIS_MODULE,
24c232d8	160	.pf = NFPROTO_IPV6,
6e23ae2a	161	.hooknum = NF_INET_LOCAL_OUT,
1da177e4 LT	162	.priority = NF_IP6_PRI_MANGLE,
	163	},
	164	{
7dd1b8da	165	.hook = ip6t_post_routing_hook,
1da177e4	166	.owner = THIS_MODULE,
24c232d8	167	.pf = NFPROTO_IPV6,
6e23ae2a	168	.hooknum = NF_INET_POST_ROUTING,
1da177e4 LT	169	.priority = NF_IP6_PRI_MANGLE,
	170	},
	171	};
	172
8280aa61 AD	173	static int __net_init ip6table_mangle_net_init(struct net *net)
	174	{
	175	/* Register table */
	176	net->ipv6.ip6table_mangle =
	177	ip6t_register_table(net, &packet_mangler, &initial_table.repl);
	178	if (IS_ERR(net->ipv6.ip6table_mangle))
	179	return PTR_ERR(net->ipv6.ip6table_mangle);
	180	return 0;
	181	}
	182
	183	static void __net_exit ip6table_mangle_net_exit(struct net *net)
	184	{
	185	ip6t_unregister_table(net->ipv6.ip6table_mangle);
	186	}
	187
	188	static struct pernet_operations ip6table_mangle_net_ops = {
	189	.init = ip6table_mangle_net_init,
	190	.exit = ip6table_mangle_net_exit,
	191	};
	192
65b4b4e8	193	static int __init ip6table_mangle_init(void)
1da177e4 LT	194	{
	195	int ret;
	196
8280aa61 AD	197	ret = register_pernet_subsys(&ip6table_mangle_net_ops);
	198	if (ret < 0)
	199	return ret;
1da177e4 LT	200
1da177e4 LT	201	/* Register hooks */
964ddaa1	202	ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
1da177e4 LT	203	if (ret < 0)
	204	goto cleanup_table;
	205
1da177e4 LT	206	return ret;
1da177e4 LT	207
1da177e4	208	cleanup_table:
8280aa61	209	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	210	return ret;
	211	}
	212
65b4b4e8	213	static void __exit ip6table_mangle_fini(void)
1da177e4	214	{
964ddaa1	215	nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
8280aa61	216	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	217	}
1da177e4 LT	218
65b4b4e8 AM	219	module_init(ip6table_mangle_init);
65b4b4e8 AM	220	module_exit(ip6table_mangle_fini);