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/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
22 struct 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
em_text_match(struct sk_buff * skb,struct tcf_ematch * m,struct tcf_pkt_info * info)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
em_text_change(struct tcf_proto * tp,void * data,int len,struct tcf_ematch * m)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
em_text_destroy(struct tcf_proto * tp,struct tcf_ematch * m)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)
106 textsearch_destroy(EM_TEXT_PRIV(m)->config);
107 }
108
em_text_dump(struct sk_buff * skb,struct tcf_ematch * m)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
init_em_text(void)143 static int __init init_em_text(void)
144 {
145 return tcf_em_register(&em_text_ops);
146 }
147
exit_em_text(void)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
158 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
159