tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* This kernel module is used to modify the connection mark values, or
2 * to optionally restore the skb nfmark from the connection mark
3 *
4 * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
5 * by Henrik Nordstrom <hno@marasystems.com>
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 as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21#include <linux/module.h>
22#include <linux/skbuff.h>
23#include <linux/ip.h>
24#include <net/checksum.h>
25
26MODULE_AUTHOR("Henrik Nordstrom <hno@marasytems.com>");
27MODULE_DESCRIPTION("IP tables CONNMARK matching module");
28MODULE_LICENSE("GPL");
29MODULE_ALIAS("ipt_CONNMARK");
30
31#include <linux/netfilter/x_tables.h>
32#include <linux/netfilter/xt_CONNMARK.h>
33#include <net/netfilter/nf_conntrack_compat.h>
34
35static unsigned int
36target(struct sk_buff **pskb,
37 const struct net_device *in,
38 const struct net_device *out,
39 unsigned int hooknum,
40 const struct xt_target *target,
41 const void *targinfo)
42{
43 const struct xt_connmark_target_info *markinfo = targinfo;
44 u_int32_t diff;
45 u_int32_t nfmark;
46 u_int32_t newmark;
47 u_int32_t ctinfo;
48 u_int32_t *ctmark = nf_ct_get_mark(*pskb, &ctinfo);
49
50 if (ctmark) {
51 switch(markinfo->mode) {
52 case XT_CONNMARK_SET:
53 newmark = (*ctmark & ~markinfo->mask) | markinfo->mark;
54 if (newmark != *ctmark) {
55 *ctmark = newmark;
56#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
57 ip_conntrack_event_cache(IPCT_MARK, *pskb);
58#else
59 nf_conntrack_event_cache(IPCT_MARK, *pskb);
60#endif
61 }
62 break;
63 case XT_CONNMARK_SAVE:
64 newmark = (*ctmark & ~markinfo->mask) |
65 ((*pskb)->nfmark & markinfo->mask);
66 if (*ctmark != newmark) {
67 *ctmark = newmark;
68#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
69 ip_conntrack_event_cache(IPCT_MARK, *pskb);
70#else
71 nf_conntrack_event_cache(IPCT_MARK, *pskb);
72#endif
73 }
74 break;
75 case XT_CONNMARK_RESTORE:
76 nfmark = (*pskb)->nfmark;
77 diff = (*ctmark ^ nfmark) & markinfo->mask;
78 if (diff != 0)
79 (*pskb)->nfmark = nfmark ^ diff;
80 break;
81 }
82 }
83
84 return XT_CONTINUE;
85}
86
87static int
88checkentry(const char *tablename,
89 const void *entry,
90 const struct xt_target *target,
91 void *targinfo,
92 unsigned int hook_mask)
93{
94 struct xt_connmark_target_info *matchinfo = targinfo;
95
96 if (matchinfo->mode == XT_CONNMARK_RESTORE) {
97 if (strcmp(tablename, "mangle") != 0) {
98 printk(KERN_WARNING "CONNMARK: restore can only be "
99 "called from \"mangle\" table, not \"%s\"\n",
100 tablename);
101 return 0;
102 }
103 }
104 if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
105 printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
106 return 0;
107 }
108 return 1;
109}
110
111#ifdef CONFIG_COMPAT
112struct compat_xt_connmark_target_info {
113 compat_ulong_t mark, mask;
114 u_int8_t mode;
115 u_int8_t __pad1;
116 u_int16_t __pad2;
117};
118
119static void compat_from_user(void *dst, void *src)
120{
121 struct compat_xt_connmark_target_info *cm = src;
122 struct xt_connmark_target_info m = {
123 .mark = cm->mark,
124 .mask = cm->mask,
125 .mode = cm->mode,
126 };
127 memcpy(dst, &m, sizeof(m));
128}
129
130static int compat_to_user(void __user *dst, void *src)
131{
132 struct xt_connmark_target_info *m = src;
133 struct compat_xt_connmark_target_info cm = {
134 .mark = m->mark,
135 .mask = m->mask,
136 .mode = m->mode,
137 };
138 return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
139}
140#endif /* CONFIG_COMPAT */
141
142static struct xt_target xt_connmark_target[] = {
143 {
144 .name = "CONNMARK",
145 .family = AF_INET,
146 .checkentry = checkentry,
147 .target = target,
148 .targetsize = sizeof(struct xt_connmark_target_info),
149#ifdef CONFIG_COMPAT
150 .compatsize = sizeof(struct compat_xt_connmark_target_info),
151 .compat_from_user = compat_from_user,
152 .compat_to_user = compat_to_user,
153#endif
154 .me = THIS_MODULE
155 },
156 {
157 .name = "CONNMARK",
158 .family = AF_INET6,
159 .checkentry = checkentry,
160 .target = target,
161 .targetsize = sizeof(struct xt_connmark_target_info),
162 .me = THIS_MODULE
163 },
164};
165
166static int __init xt_connmark_init(void)
167{
168 need_conntrack();
169 return xt_register_targets(xt_connmark_target,
170 ARRAY_SIZE(xt_connmark_target));
171}
172
173static void __exit xt_connmark_fini(void)
174{
175 xt_unregister_targets(xt_connmark_target,
176 ARRAY_SIZE(xt_connmark_target));
177}
178
179module_init(xt_connmark_init);
180module_exit(xt_connmark_fini);