[people/arne_f/kernel.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>
#include <linux/slab.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 xt_table packet_mangler = {
	.name		= "mangle",
	.valid_hooks	= MANGLE_VALID_HOOKS,
	.me		= THIS_MODULE,
	.af		= NFPROTO_IPV6,
	.priority	= NF_IP6_PRI_MANGLE,
};

static unsigned int
ip6t_mangle_out(struct sk_buff *skb, const struct net_device *out)
{
	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, NF_INET_LOCAL_OUT, 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_mangle_out(skb, out);
	if (hook == NF_INET_POST_ROUTING)
		return ip6t_do_table(skb, hook, in, out,
				     dev_net(out)->ipv6.ip6table_mangle);
	/* INPUT/FORWARD */
	return ip6t_do_table(skb, hook, in, out,
			     dev_net(in)->ipv6.ip6table_mangle);
}

static struct nf_hook_ops *mangle_ops __read_mostly;
static int __net_init ip6table_mangle_net_init(struct net *net)
{
	struct ip6t_replace *repl;

	repl = ip6t_alloc_initial_table(&packet_mangler);
	if (repl == NULL)
		return -ENOMEM;
	net->ipv6.ip6table_mangle =
		ip6t_register_table(net, &packet_mangler, repl);
	kfree(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 */
	mangle_ops = xt_hook_link(&packet_mangler, ip6table_mangle_hook);
	if (IS_ERR(mangle_ops)) {
		ret = PTR_ERR(mangle_ops);
		goto cleanup_table;
	}

	return ret;

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

static void __exit ip6table_mangle_fini(void)
{
	xt_hook_unlink(&packet_mangler, mangle_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>
5a0e3ad6	13	#include <linux/slab.h>
1da177e4 LT	14
	15	MODULE_LICENSE("GPL");
	16	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	17	MODULE_DESCRIPTION("ip6tables mangle table");
	18
6e23ae2a PM	19	#define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) \| \
	20	(1 << NF_INET_LOCAL_IN) \| \
	21	(1 << NF_INET_FORWARD) \| \
	22	(1 << NF_INET_LOCAL_OUT) \| \
	23	(1 << NF_INET_POST_ROUTING))
1da177e4	24
35aad0ff	25	static const struct xt_table packet_mangler = {
1da177e4 LT	26	.name = "mangle",
1da177e4 LT	27	.valid_hooks = MANGLE_VALID_HOOKS,
1da177e4	28	.me = THIS_MODULE,
f88e6a8a	29	.af = NFPROTO_IPV6,
2b95efe7	30	.priority = NF_IP6_PRI_MANGLE,
1da177e4 LT	31	};
1da177e4 LT	32
7dd1b8da	33	static unsigned int
fa96a0e2	34	ip6t_mangle_out(struct sk_buff skb, const struct net_device out)
1da177e4	35	{
1da177e4 LT	36	unsigned int ret;
	37	struct in6_addr saddr, daddr;
	38	u_int8_t hop_limit;
82e91ffe	39	u_int32_t flowlabel, mark;
1da177e4 LT	40
	41	#if 0
	42	/* root is playing with raw sockets. */
3666ed1c JP	43	if (skb->len < sizeof(struct iphdr) \|\|
3666ed1c JP	44	ip_hdrlen(skb) < sizeof(struct iphdr)) {
1da177e4 LT	45	if (net_ratelimit())
	46	printk("ip6t_hook: happy cracking.\n");
	47	return NF_ACCEPT;
	48	}
	49	#endif
	50
82e91ffe	51	/* save source/dest address, mark, hoplimit, flowlabel, priority, */
3db05fea HX	52	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
	53	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
	54	mark = skb->mark;
	55	hop_limit = ipv6_hdr(skb)->hop_limit;
1da177e4 LT	56
1da177e4 LT	57	/* flowlabel and prio (includes version, which shouldn't change either */
3db05fea	58	flowlabel = ((u_int32_t )ipv6_hdr(skb));
1da177e4	59
fa96a0e2	60	ret = ip6t_do_table(skb, NF_INET_LOCAL_OUT, NULL, out,
7dd1b8da	61	dev_net(out)->ipv6.ip6table_mangle);
1da177e4	62
3666ed1c JP	63	if (ret != NF_DROP && ret != NF_STOLEN &&
	64	(memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) \|\|
	65	memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) \|\|
	66	skb->mark != mark \|\|
	67	ipv6_hdr(skb)->hop_limit != hop_limit))
3db05fea	68	return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
1da177e4 LT	69
	70	return ret;
	71	}
	72
737535c5 JE	73	/* The work comes in here from netfilter.c. */
	74	static unsigned int
	75	ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb,
	76	const struct net_device in, const struct net_device out,
	77	int (okfn)(struct sk_buff ))
	78	{
	79	if (hook == NF_INET_LOCAL_OUT)
fa96a0e2	80	return ip6t_mangle_out(skb, out);
b2907e50 AD	81	if (hook == NF_INET_POST_ROUTING)
	82	return ip6t_do_table(skb, hook, in, out,
	83	dev_net(out)->ipv6.ip6table_mangle);
737535c5 JE	84	/* INPUT/FORWARD */
	85	return ip6t_do_table(skb, hook, in, out,
	86	dev_net(in)->ipv6.ip6table_mangle);
	87	}
	88
2b95efe7	89	static struct nf_hook_ops *mangle_ops __read_mostly;
8280aa61 AD	90	static int __net_init ip6table_mangle_net_init(struct net *net)
8280aa61 AD	91	{
e3eaa991 JE	92	struct ip6t_replace *repl;
	93
	94	repl = ip6t_alloc_initial_table(&packet_mangler);
	95	if (repl == NULL)
	96	return -ENOMEM;
8280aa61	97	net->ipv6.ip6table_mangle =
e3eaa991 JE	98	ip6t_register_table(net, &packet_mangler, repl);
e3eaa991 JE	99	kfree(repl);
8280aa61 AD	100	if (IS_ERR(net->ipv6.ip6table_mangle))
	101	return PTR_ERR(net->ipv6.ip6table_mangle);
	102	return 0;
	103	}
	104
	105	static void __net_exit ip6table_mangle_net_exit(struct net *net)
	106	{
f54e9367	107	ip6t_unregister_table(net, net->ipv6.ip6table_mangle);
8280aa61 AD	108	}
	109
	110	static struct pernet_operations ip6table_mangle_net_ops = {
	111	.init = ip6table_mangle_net_init,
	112	.exit = ip6table_mangle_net_exit,
	113	};
	114
65b4b4e8	115	static int __init ip6table_mangle_init(void)
1da177e4 LT	116	{
	117	int ret;
	118
8280aa61 AD	119	ret = register_pernet_subsys(&ip6table_mangle_net_ops);
	120	if (ret < 0)
	121	return ret;
1da177e4 LT	122
1da177e4 LT	123	/* Register hooks */
2b95efe7 JE	124	mangle_ops = xt_hook_link(&packet_mangler, ip6table_mangle_hook);
	125	if (IS_ERR(mangle_ops)) {
	126	ret = PTR_ERR(mangle_ops);
1da177e4	127	goto cleanup_table;
2b95efe7	128	}
1da177e4	129
1da177e4 LT	130	return ret;
1da177e4 LT	131
1da177e4	132	cleanup_table:
8280aa61	133	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	134	return ret;
	135	}
	136
65b4b4e8	137	static void __exit ip6table_mangle_fini(void)
1da177e4	138	{
2b95efe7	139	xt_hook_unlink(&packet_mangler, mangle_ops);
8280aa61	140	unregister_pernet_subsys(&ip6table_mangle_net_ops);
1da177e4 LT	141	}
1da177e4 LT	142
65b4b4e8 AM	143	module_init(ip6table_mangle_init);
65b4b4e8 AM	144	module_exit(ip6table_mangle_fini);