tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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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@marasystems.com>");
27MODULE_DESCRIPTION("IP tables CONNMARK matching module");
28MODULE_LICENSE("GPL");
29MODULE_ALIAS("ipt_CONNMARK");
30MODULE_ALIAS("ip6t_CONNMARK");
31
32#include <linux/netfilter/x_tables.h>
33#include <linux/netfilter/xt_CONNMARK.h>
34#include <net/netfilter/nf_conntrack_ecache.h>
35
36static unsigned int
37target(struct sk_buff *skb,
38 const struct net_device *in,
39 const struct net_device *out,
40 unsigned int hooknum,
41 const struct xt_target *target,
42 const void *targinfo)
43{
44 const struct xt_connmark_target_info *markinfo = targinfo;
45 struct nf_conn *ct;
46 enum ip_conntrack_info ctinfo;
47 u_int32_t diff;
48 u_int32_t mark;
49 u_int32_t newmark;
50
51 ct = nf_ct_get(skb, &ctinfo);
52 if (ct) {
53 switch(markinfo->mode) {
54 case XT_CONNMARK_SET:
55 newmark = (ct->mark & ~markinfo->mask) | markinfo->mark;
56 if (newmark != ct->mark) {
57 ct->mark = newmark;
58 nf_conntrack_event_cache(IPCT_MARK, skb);
59 }
60 break;
61 case XT_CONNMARK_SAVE:
62 newmark = (ct->mark & ~markinfo->mask) |
63 (skb->mark & markinfo->mask);
64 if (ct->mark != newmark) {
65 ct->mark = newmark;
66 nf_conntrack_event_cache(IPCT_MARK, skb);
67 }
68 break;
69 case XT_CONNMARK_RESTORE:
70 mark = skb->mark;
71 diff = (ct->mark ^ mark) & markinfo->mask;
72 skb->mark = mark ^ diff;
73 break;
74 }
75 }
76
77 return XT_CONTINUE;
78}
79
80static bool
81checkentry(const char *tablename,
82 const void *entry,
83 const struct xt_target *target,
84 void *targinfo,
85 unsigned int hook_mask)
86{
87 const struct xt_connmark_target_info *matchinfo = targinfo;
88
89 if (matchinfo->mode == XT_CONNMARK_RESTORE) {
90 if (strcmp(tablename, "mangle") != 0) {
91 printk(KERN_WARNING "CONNMARK: restore can only be "
92 "called from \"mangle\" table, not \"%s\"\n",
93 tablename);
94 return false;
95 }
96 }
97 if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
98 printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
99 return false;
100 }
101 if (nf_ct_l3proto_try_module_get(target->family) < 0) {
102 printk(KERN_WARNING "can't load conntrack support for "
103 "proto=%d\n", target->family);
104 return false;
105 }
106 return true;
107}
108
109static void
110destroy(const struct xt_target *target, void *targinfo)
111{
112 nf_ct_l3proto_module_put(target->family);
113}
114
115#ifdef CONFIG_COMPAT
116struct compat_xt_connmark_target_info {
117 compat_ulong_t mark, mask;
118 u_int8_t mode;
119 u_int8_t __pad1;
120 u_int16_t __pad2;
121};
122
123static void compat_from_user(void *dst, void *src)
124{
125 const struct compat_xt_connmark_target_info *cm = src;
126 struct xt_connmark_target_info m = {
127 .mark = cm->mark,
128 .mask = cm->mask,
129 .mode = cm->mode,
130 };
131 memcpy(dst, &m, sizeof(m));
132}
133
134static int compat_to_user(void __user *dst, void *src)
135{
136 const struct xt_connmark_target_info *m = src;
137 struct compat_xt_connmark_target_info cm = {
138 .mark = m->mark,
139 .mask = m->mask,
140 .mode = m->mode,
141 };
142 return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
143}
144#endif /* CONFIG_COMPAT */
145
146static struct xt_target xt_connmark_target[] __read_mostly = {
147 {
148 .name = "CONNMARK",
149 .family = AF_INET,
150 .checkentry = checkentry,
151 .destroy = destroy,
152 .target = target,
153 .targetsize = sizeof(struct xt_connmark_target_info),
154#ifdef CONFIG_COMPAT
155 .compatsize = sizeof(struct compat_xt_connmark_target_info),
156 .compat_from_user = compat_from_user,
157 .compat_to_user = compat_to_user,
158#endif
159 .me = THIS_MODULE
160 },
161 {
162 .name = "CONNMARK",
163 .family = AF_INET6,
164 .checkentry = checkentry,
165 .destroy = destroy,
166 .target = target,
167 .targetsize = sizeof(struct xt_connmark_target_info),
168 .me = THIS_MODULE
169 },
170};
171
172static int __init xt_connmark_init(void)
173{
174 return xt_register_targets(xt_connmark_target,
175 ARRAY_SIZE(xt_connmark_target));
176}
177
178static void __exit xt_connmark_fini(void)
179{
180 xt_unregister_targets(xt_connmark_target,
181 ARRAY_SIZE(xt_connmark_target));
182}
183
184module_init(xt_connmark_init);
185module_exit(xt_connmark_fini);