Linux Kernel  3.7.1
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em_text.c
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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 <[email protected]>
10  */
11 
12 #include <linux/slab.h>
13 #include <linux/module.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/skbuff.h>
18 #include <linux/textsearch.h>
20 #include <net/pkt_cls.h>
21 
22 struct text_match {
27  struct ts_config *config;
28 };
29 
30 #define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
31 
32 static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
33  struct tcf_pkt_info *info)
34 {
35  struct text_match *tm = EM_TEXT_PRIV(m);
36  int from, to;
37  struct ts_state state;
38 
39  from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
40  from += tm->from_offset;
41 
42  to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
43  to += tm->to_offset;
44 
45  return skb_find_text(skb, from, to, tm->config, &state) != UINT_MAX;
46 }
47 
48 static int em_text_change(struct tcf_proto *tp, void *data, int len,
49  struct tcf_ematch *m)
50 {
51  struct text_match *tm;
52  struct tcf_em_text *conf = data;
53  struct ts_config *ts_conf;
54  int flags = 0;
55 
56  if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
57  return -EINVAL;
58 
59  if (conf->from_layer > conf->to_layer)
60  return -EINVAL;
61 
62  if (conf->from_layer == conf->to_layer &&
63  conf->from_offset > conf->to_offset)
64  return -EINVAL;
65 
66 retry:
67  ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
68  conf->pattern_len, GFP_KERNEL, flags);
69 
70  if (flags & TS_AUTOLOAD)
71  rtnl_lock();
72 
73  if (IS_ERR(ts_conf)) {
74  if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
75  rtnl_unlock();
76  flags |= TS_AUTOLOAD;
77  goto retry;
78  } else
79  return PTR_ERR(ts_conf);
80  } else if (flags & TS_AUTOLOAD) {
81  textsearch_destroy(ts_conf);
82  return -EAGAIN;
83  }
84 
85  tm = kmalloc(sizeof(*tm), GFP_KERNEL);
86  if (tm == NULL) {
87  textsearch_destroy(ts_conf);
88  return -ENOBUFS;
89  }
90 
91  tm->from_offset = conf->from_offset;
92  tm->to_offset = conf->to_offset;
93  tm->from_layer = conf->from_layer;
94  tm->to_layer = conf->to_layer;
95  tm->config = ts_conf;
96 
97  m->datalen = sizeof(*tm);
98  m->data = (unsigned long) tm;
99 
100  return 0;
101 }
102 
103 static void em_text_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
104 {
105  if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config)
107 }
108 
109 static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
110 {
111  struct text_match *tm = EM_TEXT_PRIV(m);
112  struct tcf_em_text conf;
113 
114  strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1);
115  conf.from_offset = tm->from_offset;
116  conf.to_offset = tm->to_offset;
117  conf.from_layer = tm->from_layer;
118  conf.to_layer = tm->to_layer;
119  conf.pattern_len = textsearch_get_pattern_len(tm->config);
120  conf.pad = 0;
121 
122  if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0)
123  goto nla_put_failure;
124  if (nla_append(skb, conf.pattern_len,
125  textsearch_get_pattern(tm->config)) < 0)
126  goto nla_put_failure;
127  return 0;
128 
129 nla_put_failure:
130  return -1;
131 }
132 
133 static struct tcf_ematch_ops em_text_ops = {
134  .kind = TCF_EM_TEXT,
135  .change = em_text_change,
136  .match = em_text_match,
137  .destroy = em_text_destroy,
138  .dump = em_text_dump,
139  .owner = THIS_MODULE,
140  .link = LIST_HEAD_INIT(em_text_ops.link)
141 };
142 
143 static int __init init_em_text(void)
144 {
145  return tcf_em_register(&em_text_ops);
146 }
147 
148 static void __exit exit_em_text(void)
149 {
150  tcf_em_unregister(&em_text_ops);
151 }
152 
153 MODULE_LICENSE("GPL");
154 
155 module_init(init_em_text);
156 module_exit(exit_em_text);
157