Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / net / netfilter / xt_CONNMARK.c
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
26 MODULE_AUTHOR("Henrik Nordstrom <hno@marasytems.com>");
27 MODULE_DESCRIPTION("IP tables CONNMARK matching module");
28 MODULE_LICENSE("GPL");
29 MODULE_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 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
35 #include <net/netfilter/nf_conntrack_ecache.h>
36 #endif
37
38 static unsigned int
39 target(struct sk_buff **pskb,
40        const struct net_device *in,
41        const struct net_device *out,
42        unsigned int hooknum,
43        const struct xt_target *target,
44        const void *targinfo)
45 {
46         const struct xt_connmark_target_info *markinfo = targinfo;
47         u_int32_t diff;
48         u_int32_t mark;
49         u_int32_t newmark;
50         u_int32_t ctinfo;
51         u_int32_t *ctmark = nf_ct_get_mark(*pskb, &ctinfo);
52
53         if (ctmark) {
54                 switch(markinfo->mode) {
55                 case XT_CONNMARK_SET:
56                         newmark = (*ctmark & ~markinfo->mask) | markinfo->mark;
57                         if (newmark != *ctmark) {
58                                 *ctmark = newmark;
59 #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
60                                 ip_conntrack_event_cache(IPCT_MARK, *pskb);
61 #else
62                                 nf_conntrack_event_cache(IPCT_MARK, *pskb);
63 #endif
64                         }
65                         break;
66                 case XT_CONNMARK_SAVE:
67                         newmark = (*ctmark & ~markinfo->mask) |
68                                   ((*pskb)->mark & markinfo->mask);
69                         if (*ctmark != newmark) {
70                                 *ctmark = newmark;
71 #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
72                                 ip_conntrack_event_cache(IPCT_MARK, *pskb);
73 #else
74                                 nf_conntrack_event_cache(IPCT_MARK, *pskb);
75 #endif
76                         }
77                         break;
78                 case XT_CONNMARK_RESTORE:
79                         mark = (*pskb)->mark;
80                         diff = (*ctmark ^ mark) & markinfo->mask;
81                         (*pskb)->mark = mark ^ diff;
82                         break;
83                 }
84         }
85
86         return XT_CONTINUE;
87 }
88
89 static int
90 checkentry(const char *tablename,
91            const void *entry,
92            const struct xt_target *target,
93            void *targinfo,
94            unsigned int hook_mask)
95 {
96         struct xt_connmark_target_info *matchinfo = targinfo;
97
98         if (nf_ct_l3proto_try_module_get(target->family) < 0) {
99                 printk(KERN_WARNING "can't load conntrack support for "
100                                     "proto=%d\n", target->family);
101                 return 0;
102         }
103         if (matchinfo->mode == XT_CONNMARK_RESTORE) {
104                 if (strcmp(tablename, "mangle") != 0) {
105                         printk(KERN_WARNING "CONNMARK: restore can only be "
106                                "called from \"mangle\" table, not \"%s\"\n",
107                                tablename);
108                         return 0;
109                 }
110         }
111         if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
112                 printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
113                 return 0;
114         }
115         return 1;
116 }
117
118 static void
119 destroy(const struct xt_target *target, void *targinfo)
120 {
121         nf_ct_l3proto_module_put(target->family);
122 }
123
124 #ifdef CONFIG_COMPAT
125 struct compat_xt_connmark_target_info {
126         compat_ulong_t  mark, mask;
127         u_int8_t        mode;
128         u_int8_t        __pad1;
129         u_int16_t       __pad2;
130 };
131
132 static void compat_from_user(void *dst, void *src)
133 {
134         struct compat_xt_connmark_target_info *cm = src;
135         struct xt_connmark_target_info m = {
136                 .mark   = cm->mark,
137                 .mask   = cm->mask,
138                 .mode   = cm->mode,
139         };
140         memcpy(dst, &m, sizeof(m));
141 }
142
143 static int compat_to_user(void __user *dst, void *src)
144 {
145         struct xt_connmark_target_info *m = src;
146         struct compat_xt_connmark_target_info cm = {
147                 .mark   = m->mark,
148                 .mask   = m->mask,
149                 .mode   = m->mode,
150         };
151         return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
152 }
153 #endif /* CONFIG_COMPAT */
154
155 static struct xt_target xt_connmark_target[] = {
156         {
157                 .name           = "CONNMARK",
158                 .family         = AF_INET,
159                 .checkentry     = checkentry,
160                 .destroy        = destroy,
161                 .target         = target,
162                 .targetsize     = sizeof(struct xt_connmark_target_info),
163 #ifdef CONFIG_COMPAT
164                 .compatsize     = sizeof(struct compat_xt_connmark_target_info),
165                 .compat_from_user = compat_from_user,
166                 .compat_to_user = compat_to_user,
167 #endif
168                 .me             = THIS_MODULE
169         },
170         {
171                 .name           = "CONNMARK",
172                 .family         = AF_INET6,
173                 .checkentry     = checkentry,
174                 .destroy        = destroy,
175                 .target         = target,
176                 .targetsize     = sizeof(struct xt_connmark_target_info),
177                 .me             = THIS_MODULE
178         },
179 };
180
181 static int __init xt_connmark_init(void)
182 {
183         return xt_register_targets(xt_connmark_target,
184                                    ARRAY_SIZE(xt_connmark_target));
185 }
186
187 static void __exit xt_connmark_fini(void)
188 {
189         xt_unregister_targets(xt_connmark_target,
190                               ARRAY_SIZE(xt_connmark_target));
191 }
192
193 module_init(xt_connmark_init);
194 module_exit(xt_connmark_fini);