Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
[linux-2.6] / net / netfilter / xt_string.c
1 /* String matching match for iptables
2  * 
3  * (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/skbuff.h>
14 #include <linux/netfilter/x_tables.h>
15 #include <linux/netfilter/xt_string.h>
16 #include <linux/textsearch.h>
17
18 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
19 MODULE_DESCRIPTION("IP tables string match module");
20 MODULE_LICENSE("GPL");
21 MODULE_ALIAS("ipt_string");
22 MODULE_ALIAS("ip6t_string");
23
24 static int match(const struct sk_buff *skb,
25                  const struct net_device *in,
26                  const struct net_device *out,
27                  const void *matchinfo,
28                  int offset,
29                  unsigned int protoff,
30                  int *hotdrop)
31 {
32         struct ts_state state;
33         struct xt_string_info *conf = (struct xt_string_info *) matchinfo;
34
35         memset(&state, 0, sizeof(struct ts_state));
36
37         return (skb_find_text((struct sk_buff *)skb, conf->from_offset, 
38                              conf->to_offset, conf->config, &state) 
39                              != UINT_MAX) && !conf->invert;
40 }
41
42 #define STRING_TEXT_PRIV(m) ((struct xt_string_info *) m)
43
44 static int checkentry(const char *tablename,
45                       const void *ip,
46                       void *matchinfo,
47                       unsigned int matchsize,
48                       unsigned int hook_mask)
49 {
50         struct xt_string_info *conf = matchinfo;
51         struct ts_config *ts_conf;
52
53         if (matchsize != XT_ALIGN(sizeof(struct xt_string_info)))
54                 return 0;
55
56         /* Damn, can't handle this case properly with iptables... */
57         if (conf->from_offset > conf->to_offset)
58                 return 0;
59
60         ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
61                                      GFP_KERNEL, TS_AUTOLOAD);
62         if (IS_ERR(ts_conf))
63                 return 0;
64
65         conf->config = ts_conf;
66
67         return 1;
68 }
69
70 static void destroy(void *matchinfo, unsigned int matchsize)
71 {
72         textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config);
73 }
74
75 static struct xt_match string_match = {
76         .name           = "string",
77         .match          = match,
78         .checkentry     = checkentry,
79         .destroy        = destroy,
80         .me             = THIS_MODULE
81 };
82 static struct xt_match string6_match = {
83         .name           = "string",
84         .match          = match,
85         .checkentry     = checkentry,
86         .destroy        = destroy,
87         .me             = THIS_MODULE
88 };
89
90 static int __init init(void)
91 {
92         int ret;
93
94         ret = xt_register_match(AF_INET, &string_match);
95         if (ret)
96                 return ret;
97         ret = xt_register_match(AF_INET6, &string6_match);
98         if (ret)
99                 xt_unregister_match(AF_INET, &string_match);
100
101         return ret;
102 }
103
104 static void __exit fini(void)
105 {
106         xt_unregister_match(AF_INET, &string_match);
107         xt_unregister_match(AF_INET6, &string6_match);
108 }
109
110 module_init(init);
111 module_exit(fini);