aboutsummaryrefslogtreecommitdiff
path: root/net/netfilter/xt_CONNMARK.c
blob: c01524f817f04caa8a42aa5ec16dc7130fed6baf (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
172
173
174
175
176
177
178
179
180
/* This kernel module is used to modify the connection mark values, or
 * to optionally restore the skb nfmark from the connection mark
 *
 * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
 * by Henrik Nordstrom <hno@marasystems.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/checksum.h>

MODULE_AUTHOR("Henrik Nordstrom <hno@marasytems.com>");
MODULE_DESCRIPTION("IP tables CONNMARK matching module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_CONNMARK");

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_CONNMARK.h>
#include <net/netfilter/nf_conntrack_compat.h>

static unsigned int
target(struct sk_buff **pskb,
       const struct net_device *in,
       const struct net_device *out,
       unsigned int hooknum,
       const struct xt_target *target,
       const void *targinfo)
{
	const struct xt_connmark_target_info *markinfo = targinfo;
	u_int32_t diff;
	u_int32_t nfmark;
	u_int32_t newmark;
	u_int32_t ctinfo;
	u_int32_t *ctmark = nf_ct_get_mark(*pskb, &ctinfo);

	if (ctmark) {
		switch(markinfo->mode) {
		case XT_CONNMARK_SET:
			newmark = (*ctmark & ~markinfo->mask) | markinfo->mark;
			if (newmark != *ctmark) {
				*ctmark = newmark;
#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
				ip_conntrack_event_cache(IPCT_MARK, *pskb);
#else
				nf_conntrack_event_cache(IPCT_MARK, *pskb);
#endif
		}
			break;
		case XT_CONNMARK_SAVE:
			newmark = (*ctmark & ~markinfo->mask) |
				  ((*pskb)->nfmark & markinfo->mask);
			if (*ctmark != newmark) {
				*ctmark = newmark;
#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
				ip_conntrack_event_cache(IPCT_MARK, *pskb);
#else
				nf_conntrack_event_cache(IPCT_MARK, *pskb);
#endif
			}
			break;
		case XT_CONNMARK_RESTORE:
			nfmark = (*pskb)->nfmark;
			diff = (*ctmark ^ nfmark) & markinfo->mask;
			if (diff != 0)
				(*pskb)->nfmark = nfmark ^ diff;
			break;
		}
	}

	return XT_CONTINUE;
}

static int
checkentry(const char *tablename,
	   const void *entry,
	   const struct xt_target *target,
	   void *targinfo,
	   unsigned int hook_mask)
{
	struct xt_connmark_target_info *matchinfo = targinfo;

	if (matchinfo->mode == XT_CONNMARK_RESTORE) {
		if (strcmp(tablename, "mangle") != 0) {
			printk(KERN_WARNING "CONNMARK: restore can only be "
			       "called from \"mangle\" table, not \"%s\"\n",
			       tablename);
			return 0;
		}
	}
	if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
		printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
		return 0;
	}
	return 1;
}

#ifdef CONFIG_COMPAT
struct compat_xt_connmark_target_info {
	compat_ulong_t	mark, mask;
	u_int8_t	mode;
	u_int8_t	__pad1;
	u_int16_t	__pad2;
};

static void compat_from_user(void *dst, void *src)
{
	struct compat_xt_connmark_target_info *cm = src;
	struct xt_connmark_target_info m = {
		.mark	= cm->mark,
		.mask	= cm->mask,
		.mode	= cm->mode,
	};
	memcpy(dst, &m, sizeof(m));
}

static int compat_to_user(void __user *dst, void *src)
{
	struct xt_connmark_target_info *m = src;
	struct compat_xt_connmark_target_info cm = {
		.mark	= m->mark,
		.mask	= m->mask,
		.mode	= m->mode,
	};
	return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
}
#endif /* CONFIG_COMPAT */

static struct xt_target xt_connmark_target[] = {
	{
		.name		= "CONNMARK",
		.family		= AF_INET,
		.checkentry	= checkentry,
		.target		= target,
		.targetsize	= sizeof(struct xt_connmark_target_info),
#ifdef CONFIG_COMPAT
		.compatsize	= sizeof(struct compat_xt_connmark_target_info),
		.compat_from_user = compat_from_user,
		.compat_to_user	= compat_to_user,
#endif
		.me		= THIS_MODULE
	},
	{
		.name		= "CONNMARK",
		.family		= AF_INET6,
		.checkentry	= checkentry,
		.target		= target,
		.targetsize	= sizeof(struct xt_connmark_target_info),
		.me		= THIS_MODULE
	},
};

static int __init xt_connmark_init(void)
{
	need_conntrack();
	return xt_register_targets(xt_connmark_target,
				   ARRAY_SIZE(xt_connmark_target));
}

static void __exit xt_connmark_fini(void)
{
	xt_unregister_targets(xt_connmark_target,
			      ARRAY_SIZE(xt_connmark_target));
}

module_init(xt_connmark_init);
module_exit(xt_connmark_fini);