95ed267328a737bff2f683a7ee23786669a5ac0e
[linux-2.6.git] / net / netfilter / xt_CONNMARK.c
1 /*
2  *      xt_CONNMARK - Netfilter module to modify the connection mark values
3  *
4  *      Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
5  *      by Henrik Nordstrom <hno@marasystems.com>
6  *      Copyright © CC Computer Consultants GmbH, 2007 - 2008
7  *      Jan Engelhardt <jengelh@computergmbh.de>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
22  */
23 #include <linux/module.h>
24 #include <linux/skbuff.h>
25 #include <linux/ip.h>
26 #include <net/checksum.h>
27
28 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
29 MODULE_DESCRIPTION("Xtables: connection mark modification");
30 MODULE_LICENSE("GPL");
31 MODULE_ALIAS("ipt_CONNMARK");
32 MODULE_ALIAS("ip6t_CONNMARK");
33
34 #include <linux/netfilter/x_tables.h>
35 #include <linux/netfilter/xt_CONNMARK.h>
36 #include <net/netfilter/nf_conntrack_ecache.h>
37
38 static unsigned int
39 connmark_tg_v0(struct sk_buff *skb, const struct xt_target_param *par)
40 {
41         const struct xt_connmark_target_info *markinfo = par->targinfo;
42         struct nf_conn *ct;
43         enum ip_conntrack_info ctinfo;
44         u_int32_t diff;
45         u_int32_t mark;
46         u_int32_t newmark;
47
48         ct = nf_ct_get(skb, &ctinfo);
49         if (ct) {
50                 switch(markinfo->mode) {
51                 case XT_CONNMARK_SET:
52                         newmark = (ct->mark & ~markinfo->mask) | markinfo->mark;
53                         if (newmark != ct->mark) {
54                                 ct->mark = newmark;
55                                 nf_conntrack_event_cache(IPCT_MARK, ct);
56                         }
57                         break;
58                 case XT_CONNMARK_SAVE:
59                         newmark = (ct->mark & ~markinfo->mask) |
60                                   (skb->mark & markinfo->mask);
61                         if (ct->mark != newmark) {
62                                 ct->mark = newmark;
63                                 nf_conntrack_event_cache(IPCT_MARK, ct);
64                         }
65                         break;
66                 case XT_CONNMARK_RESTORE:
67                         mark = skb->mark;
68                         diff = (ct->mark ^ mark) & markinfo->mask;
69                         skb->mark = mark ^ diff;
70                         break;
71                 }
72         }
73
74         return XT_CONTINUE;
75 }
76
77 static unsigned int
78 connmark_tg(struct sk_buff *skb, const struct xt_target_param *par)
79 {
80         const struct xt_connmark_tginfo1 *info = par->targinfo;
81         enum ip_conntrack_info ctinfo;
82         struct nf_conn *ct;
83         u_int32_t newmark;
84
85         ct = nf_ct_get(skb, &ctinfo);
86         if (ct == NULL)
87                 return XT_CONTINUE;
88
89         switch (info->mode) {
90         case XT_CONNMARK_SET:
91                 newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
92                 if (ct->mark != newmark) {
93                         ct->mark = newmark;
94                         nf_conntrack_event_cache(IPCT_MARK, ct);
95                 }
96                 break;
97         case XT_CONNMARK_SAVE:
98                 newmark = (ct->mark & ~info->ctmask) ^
99                           (skb->mark & info->nfmask);
100                 if (ct->mark != newmark) {
101                         ct->mark = newmark;
102                         nf_conntrack_event_cache(IPCT_MARK, ct);
103                 }
104                 break;
105         case XT_CONNMARK_RESTORE:
106                 newmark = (skb->mark & ~info->nfmask) ^
107                           (ct->mark & info->ctmask);
108                 skb->mark = newmark;
109                 break;
110         }
111
112         return XT_CONTINUE;
113 }
114
115 static bool
116 connmark_tg_check_v0(const char *tablename, const void *entry,
117                      const struct xt_target *target, void *targinfo,
118                      unsigned int hook_mask)
119 {
120         const struct xt_connmark_target_info *matchinfo = targinfo;
121
122         if (matchinfo->mode == XT_CONNMARK_RESTORE) {
123                 if (strcmp(tablename, "mangle") != 0) {
124                         printk(KERN_WARNING "CONNMARK: restore can only be "
125                                "called from \"mangle\" table, not \"%s\"\n",
126                                tablename);
127                         return false;
128                 }
129         }
130         if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
131                 printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
132                 return false;
133         }
134         if (nf_ct_l3proto_try_module_get(target->family) < 0) {
135                 printk(KERN_WARNING "can't load conntrack support for "
136                                     "proto=%u\n", target->family);
137                 return false;
138         }
139         return true;
140 }
141
142 static bool
143 connmark_tg_check(const char *tablename, const void *entry,
144                   const struct xt_target *target, void *targinfo,
145                   unsigned int hook_mask)
146 {
147         if (nf_ct_l3proto_try_module_get(target->family) < 0) {
148                 printk(KERN_WARNING "cannot load conntrack support for "
149                        "proto=%u\n", target->family);
150                 return false;
151         }
152         return true;
153 }
154
155 static void
156 connmark_tg_destroy(const struct xt_target *target, void *targinfo)
157 {
158         nf_ct_l3proto_module_put(target->family);
159 }
160
161 #ifdef CONFIG_COMPAT
162 struct compat_xt_connmark_target_info {
163         compat_ulong_t  mark, mask;
164         u_int8_t        mode;
165         u_int8_t        __pad1;
166         u_int16_t       __pad2;
167 };
168
169 static void connmark_tg_compat_from_user_v0(void *dst, void *src)
170 {
171         const struct compat_xt_connmark_target_info *cm = src;
172         struct xt_connmark_target_info m = {
173                 .mark   = cm->mark,
174                 .mask   = cm->mask,
175                 .mode   = cm->mode,
176         };
177         memcpy(dst, &m, sizeof(m));
178 }
179
180 static int connmark_tg_compat_to_user_v0(void __user *dst, void *src)
181 {
182         const struct xt_connmark_target_info *m = src;
183         struct compat_xt_connmark_target_info cm = {
184                 .mark   = m->mark,
185                 .mask   = m->mask,
186                 .mode   = m->mode,
187         };
188         return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
189 }
190 #endif /* CONFIG_COMPAT */
191
192 static struct xt_target connmark_tg_reg[] __read_mostly = {
193         {
194                 .name           = "CONNMARK",
195                 .revision       = 0,
196                 .family         = NFPROTO_IPV4,
197                 .checkentry     = connmark_tg_check_v0,
198                 .destroy        = connmark_tg_destroy,
199                 .target         = connmark_tg_v0,
200                 .targetsize     = sizeof(struct xt_connmark_target_info),
201 #ifdef CONFIG_COMPAT
202                 .compatsize     = sizeof(struct compat_xt_connmark_target_info),
203                 .compat_from_user = connmark_tg_compat_from_user_v0,
204                 .compat_to_user = connmark_tg_compat_to_user_v0,
205 #endif
206                 .me             = THIS_MODULE
207         },
208         {
209                 .name           = "CONNMARK",
210                 .revision       = 0,
211                 .family         = NFPROTO_IPV6,
212                 .checkentry     = connmark_tg_check_v0,
213                 .destroy        = connmark_tg_destroy,
214                 .target         = connmark_tg_v0,
215                 .targetsize     = sizeof(struct xt_connmark_target_info),
216 #ifdef CONFIG_COMPAT
217                 .compatsize     = sizeof(struct compat_xt_connmark_target_info),
218                 .compat_from_user = connmark_tg_compat_from_user_v0,
219                 .compat_to_user = connmark_tg_compat_to_user_v0,
220 #endif
221                 .me             = THIS_MODULE
222         },
223         {
224                 .name           = "CONNMARK",
225                 .revision       = 1,
226                 .family         = NFPROTO_IPV4,
227                 .checkentry     = connmark_tg_check,
228                 .target         = connmark_tg,
229                 .targetsize     = sizeof(struct xt_connmark_tginfo1),
230                 .destroy        = connmark_tg_destroy,
231                 .me             = THIS_MODULE,
232         },
233         {
234                 .name           = "CONNMARK",
235                 .revision       = 1,
236                 .family         = NFPROTO_IPV6,
237                 .checkentry     = connmark_tg_check,
238                 .target         = connmark_tg,
239                 .targetsize     = sizeof(struct xt_connmark_tginfo1),
240                 .destroy        = connmark_tg_destroy,
241                 .me             = THIS_MODULE,
242         },
243 };
244
245 static int __init connmark_tg_init(void)
246 {
247         return xt_register_targets(connmark_tg_reg,
248                ARRAY_SIZE(connmark_tg_reg));
249 }
250
251 static void __exit connmark_tg_exit(void)
252 {
253         xt_unregister_targets(connmark_tg_reg, ARRAY_SIZE(connmark_tg_reg));
254 }
255
256 module_init(connmark_tg_init);
257 module_exit(connmark_tg_exit);