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
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