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[linux-2.6] / net / sched / em_text.c
1 /*
2  * net/sched/em_text.c  Textsearch ematch
3  *
4  *              This program is free software; you can redistribute it and/or
5  *              modify it under the terms of the GNU General Public License
6  *              as published by the Free Software Foundation; either version
7  *              2 of the License, or (at your option) any later version.
8  *
9  * Authors:     Thomas Graf <tgraf@suug.ch>
10  */
11
12 #include <linux/config.h>
13 #include <linux/module.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/sched.h>
17 #include <linux/string.h>
18 #include <linux/skbuff.h>
19 #include <linux/textsearch.h>
20 #include <linux/tc_ematch/tc_em_text.h>
21 #include <net/pkt_cls.h>
22
23 struct text_match
24 {
25         u16                     from_offset;
26         u16                     to_offset;
27         u8                      from_layer;
28         u8                      to_layer;
29         struct ts_config        *config;
30 };
31
32 #define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
33
34 static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
35                          struct tcf_pkt_info *info)
36 {
37         struct text_match *tm = EM_TEXT_PRIV(m);
38         int from, to;
39         struct ts_state state;
40
41         from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
42         from += tm->from_offset;
43
44         to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
45         to += tm->to_offset;
46
47         return skb_find_text(skb, from, to, tm->config, &state) != UINT_MAX;
48 }
49
50 static int em_text_change(struct tcf_proto *tp, void *data, int len,
51                           struct tcf_ematch *m)
52 {
53         struct text_match *tm;
54         struct tcf_em_text *conf = data;
55         struct ts_config *ts_conf;
56         int flags = 0;
57
58         if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
59                 return -EINVAL;
60
61         if (conf->from_layer > conf->to_layer)
62                 return -EINVAL;
63
64         if (conf->from_layer == conf->to_layer &&
65             conf->from_offset > conf->to_offset)
66                 return -EINVAL;
67
68 retry:
69         ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
70                                      conf->pattern_len, GFP_KERNEL, flags);
71
72         if (flags & TS_AUTOLOAD)
73                 rtnl_lock();
74
75         if (IS_ERR(ts_conf)) {
76                 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
77                         rtnl_unlock();
78                         flags |= TS_AUTOLOAD;
79                         goto retry;
80                 } else
81                         return PTR_ERR(ts_conf);
82         } else if (flags & TS_AUTOLOAD) {
83                 textsearch_destroy(ts_conf);
84                 return -EAGAIN;
85         }
86
87         tm = kmalloc(sizeof(*tm), GFP_KERNEL);
88         if (tm == NULL) {
89                 textsearch_destroy(ts_conf);
90                 return -ENOBUFS;
91         }
92
93         tm->from_offset = conf->from_offset;
94         tm->to_offset   = conf->to_offset;
95         tm->from_layer  = conf->from_layer;
96         tm->to_layer    = conf->to_layer;
97         tm->config      = ts_conf;
98
99         m->datalen = sizeof(*tm);
100         m->data = (unsigned long) tm;
101
102         return 0;
103 }
104
105 static void em_text_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
106 {
107         textsearch_destroy(EM_TEXT_PRIV(m)->config);
108 }
109
110 static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
111 {
112         struct text_match *tm = EM_TEXT_PRIV(m);
113         struct tcf_em_text conf;
114
115         strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1);
116         conf.from_offset = tm->from_offset;
117         conf.to_offset = tm->to_offset;
118         conf.from_layer = tm->from_layer;
119         conf.to_layer = tm->to_layer;
120         conf.pattern_len = textsearch_get_pattern_len(tm->config);
121         conf.pad = 0;
122
123         RTA_PUT_NOHDR(skb, sizeof(conf), &conf);
124         RTA_APPEND(skb, conf.pattern_len, textsearch_get_pattern(tm->config));
125         return 0;
126
127 rtattr_failure:
128         return -1;
129 }               
130
131 static struct tcf_ematch_ops em_text_ops = {
132         .kind     = TCF_EM_TEXT,
133         .change   = em_text_change,
134         .match    = em_text_match,
135         .destroy  = em_text_destroy,
136         .dump     = em_text_dump,
137         .owner    = THIS_MODULE,
138         .link     = LIST_HEAD_INIT(em_text_ops.link)
139 };
140
141 static int __init init_em_text(void)
142 {
143         return tcf_em_register(&em_text_ops);
144 }
145
146 static void __exit exit_em_text(void) 
147 {
148         tcf_em_unregister(&em_text_ops);
149 }
150
151 MODULE_LICENSE("GPL");
152
153 module_init(init_em_text);
154 module_exit(exit_em_text);