aboutsummaryrefslogtreecommitdiff
path: root/net/netfilter/xt_dscp.c
blob: 26f4aab9c42943ce4bcb7cf57bc3630ac3bdc3e1 (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
/* IP tables module for matching the value of the IPv4/IPv6 DSCP field
 *
 * (C) 2002 by Harald Welte <laforge@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/skbuff.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/dsfield.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_dscp.h>
#include <linux/netfilter_ipv4/ipt_tos.h>

MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("Xtables: DSCP/TOS field match");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_dscp");
MODULE_ALIAS("ip6t_dscp");
MODULE_ALIAS("ipt_tos");
MODULE_ALIAS("ip6t_tos");

static bool
dscp_mt(const struct sk_buff *skb, const struct net_device *in,
        const struct net_device *out, const struct xt_match *match,
        const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
{
	const struct xt_dscp_info *info = matchinfo;
	u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT;

	return (dscp == info->dscp) ^ !!info->invert;
}

static bool
dscp_mt6(const struct sk_buff *skb, const struct net_device *in,
         const struct net_device *out, const struct xt_match *match,
         const void *matchinfo, int offset, unsigned int protoff,
         bool *hotdrop)
{
	const struct xt_dscp_info *info = matchinfo;
	u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT;

	return (dscp == info->dscp) ^ !!info->invert;
}

static bool
dscp_mt_check(const char *tablename, const void *info,
              const struct xt_match *match, void *matchinfo,
              unsigned int hook_mask)
{
	const u_int8_t dscp = ((struct xt_dscp_info *)matchinfo)->dscp;

	if (dscp > XT_DSCP_MAX) {
		printk(KERN_ERR "xt_dscp: dscp %x out of range\n", dscp);
		return false;
	}

	return true;
}

static bool tos_mt_v0(const struct sk_buff *skb, const struct net_device *in,
                      const struct net_device *out,
                      const struct xt_match *match, const void *matchinfo,
                      int offset, unsigned int protoff, bool *hotdrop)
{
	const struct ipt_tos_info *info = matchinfo;

	return (ip_hdr(skb)->tos == info->tos) ^ info->invert;
}

static bool tos_mt(const struct sk_buff *skb, const struct net_device *in,
                   const struct net_device *out, const struct xt_match *match,
                   const void *matchinfo, int offset, unsigned int protoff,
                   bool *hotdrop)
{
	const struct xt_tos_match_info *info = matchinfo;

	if (match->family == AF_INET)
		return ((ip_hdr(skb)->tos & info->tos_mask) ==
		       info->tos_value) ^ !!info->invert;
	else
		return ((ipv6_get_dsfield(ipv6_hdr(skb)) & info->tos_mask) ==
		       info->tos_value) ^ !!info->invert;
}

static struct xt_match dscp_mt_reg[] __read_mostly = {
	{
		.name		= "dscp",
		.family		= AF_INET,
		.checkentry	= dscp_mt_check,
		.match		= dscp_mt,
		.matchsize	= sizeof(struct xt_dscp_info),
		.me		= THIS_MODULE,
	},
	{
		.name		= "dscp",
		.family		= AF_INET6,
		.checkentry	= dscp_mt_check,
		.match		= dscp_mt6,
		.matchsize	= sizeof(struct xt_dscp_info),
		.me		= THIS_MODULE,
	},
	{
		.name		= "tos",
		.revision	= 0,
		.family		= AF_INET,
		.match		= tos_mt_v0,
		.matchsize	= sizeof(struct ipt_tos_info),
		.me		= THIS_MODULE,
	},
	{
		.name		= "tos",
		.revision	= 1,
		.family		= AF_INET,
		.match		= tos_mt,
		.matchsize	= sizeof(struct xt_tos_match_info),
		.me		= THIS_MODULE,
	},
	{
		.name		= "tos",
		.revision	= 1,
		.family		= AF_INET6,
		.match		= tos_mt,
		.matchsize	= sizeof(struct xt_tos_match_info),
		.me		= THIS_MODULE,
	},
};

static int __init dscp_mt_init(void)
{
	return xt_register_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
}

static void __exit dscp_mt_exit(void)
{
	xt_unregister_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
}

module_init(dscp_mt_init);
module_exit(dscp_mt_exit);