[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,
};

static unsigned int
ip6t_local_out_hook(unsigned int hook,
		   struct sk_buff *skb,
		   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, NULL, 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;
}

/* The work comes in here from netfilter.c. */
static unsigned int
ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb,
		     const struct net_device *in, const struct net_device *out,
		     int (*okfn)(struct sk_buff *))
{
	if (hook == NF_INET_LOCAL_OUT)
		return ip6t_local_out_hook(hook, skb, out, okfn);

	/* INPUT/FORWARD */
	return ip6t_do_table(skb, hook, in, out,
			     dev_net(in)->ipv6.ip6table_mangle);
}

static struct nf_hook_ops ip6t_ops[] __read_mostly = {
	{
		.hook		= ip6table_mangle_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.hooknum	= NF_INET_PRE_ROUTING,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6table_mangle_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.hooknum	= NF_INET_LOCAL_IN,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6table_mangle_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.hooknum	= NF_INET_FORWARD,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6table_mangle_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV6,
		.hooknum	= NF_INET_LOCAL_OUT,
		.priority	= NF_IP6_PRI_MANGLE,
	},
	{
		.hook		= ip6table_mangle_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, 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	};
1da177e4 LT	66
7dd1b8da AD	67	static unsigned int
7dd1b8da AD	68	ip6t_local_out_hook(unsigned int hook,
3db05fea	69	struct sk_buff *skb,
1da177e4 LT	70	const struct net_device *out,
	71	int (okfn)(struct sk_buff ))
	72	{
	73
1da177e4 LT	74	unsigned int ret;
	75	struct in6_addr saddr, daddr;
	76	u_int8_t hop_limit;
82e91ffe	77	u_int32_t flowlabel, mark;
1da177e4 LT	78
	79	#if 0
	80	/* root is playing with raw sockets. */
3666ed1c JP	81	if (skb->len < sizeof(struct iphdr) \|\|
3666ed1c JP	82	ip_hdrlen(skb) < sizeof(struct iphdr)) {
1da177e4 LT	83	if (net_ratelimit())
	84	printk("ip6t_hook: happy cracking.\n");
	85	return NF_ACCEPT;
	86	}
	87	#endif
	88
82e91ffe	89	/* save source/dest address, mark, hoplimit, flowlabel, priority, */
3db05fea HX	90	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
	91	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
	92	mark = skb->mark;
	93	hop_limit = ipv6_hdr(skb)->hop_limit;
1da177e4 LT	94
1da177e4 LT	95	/* flowlabel and prio (includes version, which shouldn't change either */
3db05fea	96	flowlabel = ((u_int32_t )ipv6_hdr(skb));
1da177e4	97
737535c5	98	ret = ip6t_do_table(skb, hook, NULL, out,
7dd1b8da	99	dev_net(out)->ipv6.ip6table_mangle);
1da177e4	100
3666ed1c JP	101	if (ret != NF_DROP && ret != NF_STOLEN &&
	102	(memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) \|\|
	103	memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) \|\|
	104	skb->mark != mark \|\|
	105	ipv6_hdr(skb)->hop_limit != hop_limit))
3db05fea	106	return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
1da177e4 LT	107
	108	return ret;
	109	}
	110
737535c5 JE	111	/* The work comes in here from netfilter.c. */
	112	static unsigned int
	113	ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb,
	114	const struct net_device in, const struct net_device out,
	115	int (okfn)(struct sk_buff ))
	116	{
	117	if (hook == NF_INET_LOCAL_OUT)
	118	return ip6t_local_out_hook(hook, skb, out, okfn);
	119
	120	/* INPUT/FORWARD */
	121	return ip6t_do_table(skb, hook, in, out,
	122	dev_net(in)->ipv6.ip6table_mangle);
	123	}
	124
1999414a	125	static struct nf_hook_ops ip6t_ops[] __read_mostly = {
1da177e4	126	{
737535c5	127	.hook = ip6table_mangle_hook,
1da177e4	128	.owner = THIS_MODULE,
24c232d8	129	.pf = NFPROTO_IPV6,
6e23ae2a	130	.hooknum = NF_INET_PRE_ROUTING,
1da177e4 LT	131	.priority = NF_IP6_PRI_MANGLE,
	132	},
	133	{
737535c5	134	.hook = ip6table_mangle_hook,
1da177e4	135	.owner = THIS_MODULE,
24c232d8	136	.pf = NFPROTO_IPV6,
6e23ae2a	137	.hooknum = NF_INET_LOCAL_IN,
1da177e4 LT	138	.priority = NF_IP6_PRI_MANGLE,
	139	},
	140	{
737535c5	141	.hook = ip6table_mangle_hook,
1da177e4	142	.owner = THIS_MODULE,
24c232d8	143	.pf = NFPROTO_IPV6,
6e23ae2a	144	.hooknum = NF_INET_FORWARD,
1da177e4 LT	145	.priority = NF_IP6_PRI_MANGLE,
	146	},
	147	{
737535c5	148	.hook = ip6table_mangle_hook,
1da177e4	149	.owner = THIS_MODULE,
24c232d8	150	.pf = NFPROTO_IPV6,
6e23ae2a	151	.hooknum = NF_INET_LOCAL_OUT,
1da177e4 LT	152	.priority = NF_IP6_PRI_MANGLE,
	153	},
	154	{
737535c5	155	.hook = ip6table_mangle_hook,
1da177e4	156	.owner = THIS_MODULE,
24c232d8	157	.pf = NFPROTO_IPV6,
6e23ae2a	158	.hooknum = NF_INET_POST_ROUTING,
1da177e4 LT	159	.priority = NF_IP6_PRI_MANGLE,
	160	},
	161	};
	162
8280aa61 AD	163	static int __net_init ip6table_mangle_net_init(struct net *net)
	164	{
	165	/* Register table */
	166	net->ipv6.ip6table_mangle =
	167	ip6t_register_table(net, &packet_mangler, &initial_table.repl);
	168	if (IS_ERR(net->ipv6.ip6table_mangle))
	169	return PTR_ERR(net->ipv6.ip6table_mangle);
	170	return 0;
	171	}
	172
	173	static void __net_exit ip6table_mangle_net_exit(struct net *net)
	174	{
f54e9367	175	ip6t_unregister_table(net, net->ipv6.ip6table_mangle);
8280aa61 AD	176	}
	177
	178	static struct pernet_operations ip6table_mangle_net_ops = {
	179	.init = ip6table_mangle_net_init,
	180	.exit = ip6table_mangle_net_exit,
	181	};
	182
65b4b4e8	183	static int __init ip6table_mangle_init(void)
1da177e4 LT	184	{
	185	int ret;
	186
8280aa61 AD	187	ret = register_pernet_subsys(&ip6table_mangle_net_ops);
	188	if (ret < 0)
	189	return ret;
1da177e4 LT	190
1da177e4 LT	191	/* Register hooks */
964ddaa1	192	ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
1da177e4 LT	193	if (ret < 0)
	194	goto cleanup_table;
	195
1da177e4 LT	196	return ret;
1da177e4 LT	197
1da177e4	198	cleanup_table:
8280aa61	199	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	200	return ret;
	201	}
	202
65b4b4e8	203	static void __exit ip6table_mangle_fini(void)
1da177e4	204	{
964ddaa1	205	nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
8280aa61	206	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	207	}
1da177e4 LT	208
65b4b4e8 AM	209	module_init(ip6table_mangle_init);
65b4b4e8 AM	210	module_exit(ip6table_mangle_fini);