summaryrefslogtreecommitdiffstats
path: root/net/netfilter/xt_TEE.c
blob: 0471db4032c5ea6eb839229124762cbf1901e53f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/*
 *	"TEE" target extension for Xtables
 *	Copyright © Sebastian Claßen, 2007
 *	Jan Engelhardt, 2007-2010
 *
 *	based on ipt_ROUTE.c from Cédric de Launois
 *	<delaunois@info.ucl.be>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	version 2 or later, as published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/route.h>
#include <linux/netfilter/x_tables.h>
#include <net/route.h>
#include <net/netfilter/ipv4/nf_dup_ipv4.h>
#include <net/netfilter/ipv6/nf_dup_ipv6.h>
#include <linux/netfilter/xt_TEE.h>

struct xt_tee_priv {
	struct notifier_block	notifier;
	struct xt_tee_tginfo	*tginfo;
	int			oif;
};

static const union nf_inet_addr tee_zero_address;

static unsigned int
tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct xt_tee_tginfo *info = par->targinfo;
	int oif = info->priv ? info->priv->oif : 0;

	nf_dup_ipv4(par->net, skb, par->hooknum, &info->gw.in, oif);

	return XT_CONTINUE;
}

#if IS_ENABLED(CONFIG_IPV6)
static unsigned int
tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct xt_tee_tginfo *info = par->targinfo;
	int oif = info->priv ? info->priv->oif : 0;

	nf_dup_ipv6(par->net, skb, par->hooknum, &info->gw.in6, oif);

	return XT_CONTINUE;
}
#endif

static int tee_netdev_event(struct notifier_block *this, unsigned long event,
			    void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct xt_tee_priv *priv;

	priv = container_of(this, struct xt_tee_priv, notifier);
	switch (event) {
	case NETDEV_REGISTER:
		if (!strcmp(dev->name, priv->tginfo->oif))
			priv->oif = dev->ifindex;
		break;
	case NETDEV_UNREGISTER:
		if (dev->ifindex == priv->oif)
			priv->oif = -1;
		break;
	case NETDEV_CHANGENAME:
		if (!strcmp(dev->name, priv->tginfo->oif))
			priv->oif = dev->ifindex;
		else if (dev->ifindex == priv->oif)
			priv->oif = -1;
		break;
	}

	return NOTIFY_DONE;
}

static int tee_tg_check(const struct xt_tgchk_param *par)
{
	struct xt_tee_tginfo *info = par->targinfo;
	struct xt_tee_priv *priv;

	/* 0.0.0.0 and :: not allowed */
	if (memcmp(&info->gw, &tee_zero_address,
		   sizeof(tee_zero_address)) == 0)
		return -EINVAL;

	if (info->oif[0]) {
		int ret;

		if (info->oif[sizeof(info->oif)-1] != '\0')
			return -EINVAL;

		priv = kzalloc(sizeof(*priv), GFP_KERNEL);
		if (priv == NULL)
			return -ENOMEM;

		priv->tginfo  = info;
		priv->oif     = -1;
		priv->notifier.notifier_call = tee_netdev_event;
		info->priv    = priv;

		ret = register_netdevice_notifier(&priv->notifier);
		if (ret) {
			kfree(priv);
			return ret;
		}
	} else
		info->priv = NULL;

	static_key_slow_inc(&xt_tee_enabled);
	return 0;
}

static void tee_tg_destroy(const struct xt_tgdtor_param *par)
{
	struct xt_tee_tginfo *info = par->targinfo;

	if (info->priv) {
		unregister_netdevice_notifier(&info->priv->notifier);
		kfree(info->priv);
	}
	static_key_slow_dec(&xt_tee_enabled);
}

static struct xt_target tee_tg_reg[] __read_mostly = {
	{
		.name       = "TEE",
		.revision   = 1,
		.family     = NFPROTO_IPV4,
		.target     = tee_tg4,
		.targetsize = sizeof(struct xt_tee_tginfo),
		.checkentry = tee_tg_check,
		.destroy    = tee_tg_destroy,
		.me         = THIS_MODULE,
	},
#if IS_ENABLED(CONFIG_IPV6)
	{
		.name       = "TEE",
		.revision   = 1,
		.family     = NFPROTO_IPV6,
		.target     = tee_tg6,
		.targetsize = sizeof(struct xt_tee_tginfo),
		.checkentry = tee_tg_check,
		.destroy    = tee_tg_destroy,
		.me         = THIS_MODULE,
	},
#endif
};

static int __init tee_tg_init(void)
{
	return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
}

static void __exit tee_tg_exit(void)
{
	xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
}

module_init(tee_tg_init);
module_exit(tee_tg_exit);
MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("Xtables: Reroute packet copy");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_TEE");
MODULE_ALIAS("ip6t_TEE");