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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>
19#include <linux/tc_ematch/tc_em_text.h>
20#include <net/pkt_cls.h>
21
22struct text_match {
23 u16 from_offset;
24 u16 to_offset;
25 u8 from_layer;
26 u8 to_layer;
27 struct ts_config *config;
28};
29
30#define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
31
32static 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
38 from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
39 from += tm->from_offset;
40
41 to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
42 to += tm->to_offset;
43
44 return skb_find_text(skb, from, to, tm->config) != UINT_MAX;
45}
46
47static int em_text_change(struct net *net, void *data, int len,
48 struct tcf_ematch *m)
49{
50 struct text_match *tm;
51 struct tcf_em_text *conf = data;
52 struct ts_config *ts_conf;
53 int flags = 0;
54
55 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
56 return -EINVAL;
57
58 if (conf->from_layer > conf->to_layer)
59 return -EINVAL;
60
61 if (conf->from_layer == conf->to_layer &&
62 conf->from_offset > conf->to_offset)
63 return -EINVAL;
64
65retry:
66 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
67 conf->pattern_len, GFP_KERNEL, flags);
68
69 if (flags & TS_AUTOLOAD)
70 rtnl_lock();
71
72 if (IS_ERR(ts_conf)) {
73 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
74 rtnl_unlock();
75 flags |= TS_AUTOLOAD;
76 goto retry;
77 } else
78 return PTR_ERR(ts_conf);
79 } else if (flags & TS_AUTOLOAD) {
80 textsearch_destroy(ts_conf);
81 return -EAGAIN;
82 }
83
84 tm = kmalloc(sizeof(*tm), GFP_KERNEL);
85 if (tm == NULL) {
86 textsearch_destroy(ts_conf);
87 return -ENOBUFS;
88 }
89
90 tm->from_offset = conf->from_offset;
91 tm->to_offset = conf->to_offset;
92 tm->from_layer = conf->from_layer;
93 tm->to_layer = conf->to_layer;
94 tm->config = ts_conf;
95
96 m->datalen = sizeof(*tm);
97 m->data = (unsigned long) tm;
98
99 return 0;
100}
101
102static void em_text_destroy(struct tcf_ematch *m)
103{
104 if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config)
105 textsearch_destroy(EM_TEXT_PRIV(m)->config);
106}
107
108static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
109{
110 struct text_match *tm = EM_TEXT_PRIV(m);
111 struct tcf_em_text conf;
112
113 strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1);
114 conf.from_offset = tm->from_offset;
115 conf.to_offset = tm->to_offset;
116 conf.from_layer = tm->from_layer;
117 conf.to_layer = tm->to_layer;
118 conf.pattern_len = textsearch_get_pattern_len(tm->config);
119 conf.pad = 0;
120
121 if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0)
122 goto nla_put_failure;
123 if (nla_append(skb, conf.pattern_len,
124 textsearch_get_pattern(tm->config)) < 0)
125 goto nla_put_failure;
126 return 0;
127
128nla_put_failure:
129 return -1;
130}
131
132static struct tcf_ematch_ops em_text_ops = {
133 .kind = TCF_EM_TEXT,
134 .change = em_text_change,
135 .match = em_text_match,
136 .destroy = em_text_destroy,
137 .dump = em_text_dump,
138 .owner = THIS_MODULE,
139 .link = LIST_HEAD_INIT(em_text_ops.link)
140};
141
142static int __init init_em_text(void)
143{
144 return tcf_em_register(&em_text_ops);
145}
146
147static void __exit exit_em_text(void)
148{
149 tcf_em_unregister(&em_text_ops);
150}
151
152MODULE_LICENSE("GPL");
153
154module_init(init_em_text);
155module_exit(exit_em_text);
156
157MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
158
