aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv4/netfilter/ipt_addrtype.c
blob: 81197f456d7f2782eec4e1bbadb51c7befa625d8 (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
/*
 *  iptables module to match inet_addr_type() of an ip.
 *
 *  Copyright (c) 2004 Patrick McHardy <kaber@trash.net>
 *  (C) 2007 Laszlo Attila Toth <panther@balabit.hu>
 *
 *  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.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/ip.h>
#include <net/route.h>

#include <linux/netfilter_ipv4/ipt_addrtype.h>
#include <linux/netfilter/x_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("Xtables: address type match for IPv4");

static inline bool match_type(struct net *net, const struct net_device *dev,
			      __be32 addr, u_int16_t mask)
{
	return !!(mask & (1 << inet_dev_addr_type(net, dev, addr)));
}

static bool
addrtype_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
{
	struct net *net = dev_net(par->in ? par->in : par->out);
	const struct ipt_addrtype_info *info = par->matchinfo;
	const struct iphdr *iph = ip_hdr(skb);
	bool ret = true;

	if (info->source)
		ret &= match_type(net, NULL, iph->saddr, info->source) ^
		       info->invert_source;
	if (info->dest)
		ret &= match_type(net, NULL, iph->daddr, info->dest) ^
		       info->invert_dest;

	return ret;
}

static bool
addrtype_mt_v1(const struct sk_buff *skb, const struct xt_match_param *par)
{
	struct net *net = dev_net(par->in ? par->in : par->out);
	const struct ipt_addrtype_info_v1 *info = par->matchinfo;
	const struct iphdr *iph = ip_hdr(skb);
	const struct net_device *dev = NULL;
	bool ret = true;

	if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN)
		dev = par->in;
	else if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT)
		dev = par->out;

	if (info->source)
		ret &= match_type(net, dev, iph->saddr, info->source) ^
		       (info->flags & IPT_ADDRTYPE_INVERT_SOURCE);
	if (ret && info->dest)
		ret &= match_type(net, dev, iph->daddr, info->dest) ^
		       !!(info->flags & IPT_ADDRTYPE_INVERT_DEST);
	return ret;
}

static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
{
	struct ipt_addrtype_info_v1 *info = par->matchinfo;

	if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN &&
	    info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT) {
		pr_info("both incoming and outgoing "
			"interface limitation cannot be selected\n");
		return false;
	}

	if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) |
	    (1 << NF_INET_LOCAL_IN)) &&
	    info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT) {
		pr_info("output interface limitation "
			"not valid in PREROUTING and INPUT\n");
		return false;
	}

	if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) |
	    (1 << NF_INET_LOCAL_OUT)) &&
	    info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN) {
		pr_info("input interface limitation "
			"not valid in POSTROUTING and OUTPUT\n");
		return false;
	}

	return true;
}

static struct xt_match addrtype_mt_reg[] __read_mostly = {
	{
		.name		= "addrtype",
		.family		= NFPROTO_IPV4,
		.match		= addrtype_mt_v0,
		.matchsize	= sizeof(struct ipt_addrtype_info),
		.me		= THIS_MODULE
	},
	{
		.name		= "addrtype",
		.family		= NFPROTO_IPV4,
		.revision	= 1,
		.match		= addrtype_mt_v1,
		.checkentry	= addrtype_mt_checkentry_v1,
		.matchsize	= sizeof(struct ipt_addrtype_info_v1),
		.me		= THIS_MODULE
	}
};

static int __init addrtype_mt_init(void)
{
	return xt_register_matches(addrtype_mt_reg,
				   ARRAY_SIZE(addrtype_mt_reg));
}

static void __exit addrtype_mt_exit(void)
{
	xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
}

module_init(addrtype_mt_init);
module_exit(addrtype_mt_exit);