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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{
24 u16 from_offset;
25 u16 to_offset;
26 u8 from_layer;
27 u8 to_layer;
28 struct ts_config *config;
29};
30
31#define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
32
33static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
34 struct tcf_pkt_info *info)
35{
36 struct text_match *tm = EM_TEXT_PRIV(m);
37 int from, to;
38 struct ts_state state;
39
40 from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
41 from += tm->from_offset;
42
43 to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
44 to += tm->to_offset;
45
46 return skb_find_text(skb, from, to, tm->config, &state) != UINT_MAX;
47}
48
49static int em_text_change(struct tcf_proto *tp, void *data, int len,
50 struct tcf_ematch *m)
51{
52 struct text_match *tm;
53 struct tcf_em_text *conf = data;
54 struct ts_config *ts_conf;
55 int flags = 0;
56
57 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
58 return -EINVAL;
59
60 if (conf->from_layer > conf->to_layer)
61 return -EINVAL;
62
63 if (conf->from_layer == conf->to_layer &&
64 conf->from_offset > conf->to_offset)
65 return -EINVAL;
66
67retry:
68 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
69 conf->pattern_len, GFP_KERNEL, flags);
70
71 if (flags & TS_AUTOLOAD)
72 rtnl_lock();
73
74 if (IS_ERR(ts_conf)) {
75 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
76 rtnl_unlock();
77 flags |= TS_AUTOLOAD;
78 goto retry;
79 } else
80 return PTR_ERR(ts_conf);
81 } else if (flags & TS_AUTOLOAD) {
82 textsearch_destroy(ts_conf);
83 return -EAGAIN;
84 }
85
86 tm = kmalloc(sizeof(*tm), GFP_KERNEL);
87 if (tm == NULL) {
88 textsearch_destroy(ts_conf);
89 return -ENOBUFS;
90 }
91
92 tm->from_offset = conf->from_offset;
93 tm->to_offset = conf->to_offset;
94 tm->from_layer = conf->from_layer;
95 tm->to_layer = conf->to_layer;
96 tm->config = ts_conf;
97
98 m->datalen = sizeof(*tm);
99 m->data = (unsigned long) tm;
100
101 return 0;
102}
103
104static void em_text_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
105{
106 if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config)
107 textsearch_destroy(EM_TEXT_PRIV(m)->config);
108}
109
110static 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 if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0)
124 goto nla_put_failure;
125 if (nla_append(skb, conf.pattern_len,
126 textsearch_get_pattern(tm->config)) < 0)
127 goto nla_put_failure;
128 return 0;
129
130nla_put_failure:
131 return -1;
132}
133
134static struct tcf_ematch_ops em_text_ops = {
135 .kind = TCF_EM_TEXT,
136 .change = em_text_change,
137 .match = em_text_match,
138 .destroy = em_text_destroy,
139 .dump = em_text_dump,
140 .owner = THIS_MODULE,
141 .link = LIST_HEAD_INIT(em_text_ops.link)
142};
143
144static int __init init_em_text(void)
145{
146 return tcf_em_register(&em_text_ops);
147}
148
149static void __exit exit_em_text(void)
150{
151 tcf_em_unregister(&em_text_ops);
152}
153
154MODULE_LICENSE("GPL");
155
156module_init(init_em_text);
157module_exit(exit_em_text);
158
159MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
160
