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
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	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
48static int em_text_change(struct net *net, 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
66retry:
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
103static void em_text_destroy(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
109static 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
129nla_put_failure:
130	return -1;
131}
132
133static 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
143static int __init init_em_text(void)
144{
145	return tcf_em_register(&em_text_ops);
146}
147
148static void __exit exit_em_text(void)
149{
150	tcf_em_unregister(&em_text_ops);
151}
152
153MODULE_LICENSE("GPL");
154
155module_init(init_em_text);
156module_exit(exit_em_text);
157
158MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
159