Pull mem-attribute into release branch
[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_ecache.h>
34
35 static unsigned int
36 target(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         struct nf_conn *ct;
45         enum ip_conntrack_info ctinfo;
46         u_int32_t diff;
47         u_int32_t mark;
48         u_int32_t newmark;
49
50         ct = nf_ct_get(*pskb, &ctinfo);
51         if (ct) {
52                 switch(markinfo->mode) {
53                 case XT_CONNMARK_SET:
54                         newmark = (ct->mark & ~markinfo->mask) | markinfo->mark;
55                         if (newmark != ct->mark) {
56                                 ct->mark = newmark;
57                                 nf_conntrack_event_cache(IPCT_MARK, *pskb);
58                         }
59                         break;
60                 case XT_CONNMARK_SAVE:
61                         newmark = (ct->mark & ~markinfo->mask) |
62                                   ((*pskb)->mark & markinfo->mask);
63                         if (ct->mark != newmark) {
64                                 ct->mark = newmark;
65                                 nf_conntrack_event_cache(IPCT_MARK, *pskb);
66                         }
67                         break;
68                 case XT_CONNMARK_RESTORE:
69                         mark = (*pskb)->mark;
70                         diff = (ct->mark ^ mark) & markinfo->mask;
71                         (*pskb)->mark = mark ^ diff;
72                         break;
73                 }
74         }
75
76         return XT_CONTINUE;
77 }
78
79 static int
80 checkentry(const char *tablename,
81            const void *entry,
82            const struct xt_target *target,
83            void *targinfo,
84            unsigned int hook_mask)
85 {
86         struct xt_connmark_target_info *matchinfo = targinfo;
87
88         if (nf_ct_l3proto_try_module_get(target->family) < 0) {
89                 printk(KERN_WARNING "can't load conntrack support for "
90                                     "proto=%d\n", target->family);
91                 return 0;
92         }
93         if (matchinfo->mode == XT_CONNMARK_RESTORE) {
94                 if (strcmp(tablename, "mangle") != 0) {
95                         printk(KERN_WARNING "CONNMARK: restore can only be "
96                                "called from \"mangle\" table, not \"%s\"\n",
97                                tablename);
98                         return 0;
99                 }
100         }
101         if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
102                 printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
103                 return 0;
104         }
105         return 1;
106 }
107
108 static void
109 destroy(const struct xt_target *target, void *targinfo)
110 {
111         nf_ct_l3proto_module_put(target->family);
112 }
113
114 #ifdef CONFIG_COMPAT
115 struct compat_xt_connmark_target_info {
116         compat_ulong_t  mark, mask;
117         u_int8_t        mode;
118         u_int8_t        __pad1;
119         u_int16_t       __pad2;
120 };
121
122 static void compat_from_user(void *dst, void *src)
123 {
124         struct compat_xt_connmark_target_info *cm = src;
125         struct xt_connmark_target_info m = {
126                 .mark   = cm->mark,
127                 .mask   = cm->mask,
128                 .mode   = cm->mode,
129         };
130         memcpy(dst, &m, sizeof(m));
131 }
132
133 static int compat_to_user(void __user *dst, void *src)
134 {
135         struct xt_connmark_target_info *m = src;
136         struct compat_xt_connmark_target_info cm = {
137                 .mark   = m->mark,
138                 .mask   = m->mask,
139                 .mode   = m->mode,
140         };
141         return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
142 }
143 #endif /* CONFIG_COMPAT */
144
145 static struct xt_target xt_connmark_target[] = {
146         {
147                 .name           = "CONNMARK",
148                 .family         = AF_INET,
149                 .checkentry     = checkentry,
150                 .destroy        = destroy,
151                 .target         = target,
152                 .targetsize     = sizeof(struct xt_connmark_target_info),
153 #ifdef CONFIG_COMPAT
154                 .compatsize     = sizeof(struct compat_xt_connmark_target_info),
155                 .compat_from_user = compat_from_user,
156                 .compat_to_user = compat_to_user,
157 #endif
158                 .me             = THIS_MODULE
159         },
160         {
161                 .name           = "CONNMARK",
162                 .family         = AF_INET6,
163                 .checkentry     = checkentry,
164                 .destroy        = destroy,
165                 .target         = target,
166                 .targetsize     = sizeof(struct xt_connmark_target_info),
167                 .me             = THIS_MODULE
168         },
169 };
170
171 static int __init xt_connmark_init(void)
172 {
173         return xt_register_targets(xt_connmark_target,
174                                    ARRAY_SIZE(xt_connmark_target));
175 }
176
177 static void __exit xt_connmark_fini(void)
178 {
179         xt_unregister_targets(xt_connmark_target,
180                               ARRAY_SIZE(xt_connmark_target));
181 }
182
183 module_init(xt_connmark_init);
184 module_exit(xt_connmark_fini);