xref: /openbmc/linux/net/sched/em_text.c (revision 4800cd83)
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 {
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 
33 static 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 
49 static 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 
67 retry:
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 
104 static 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 
110 static 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 
130 nla_put_failure:
131 	return -1;
132 }
133 
134 static 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 
144 static int __init init_em_text(void)
145 {
146 	return tcf_em_register(&em_text_ops);
147 }
148 
149 static void __exit exit_em_text(void)
150 {
151 	tcf_em_unregister(&em_text_ops);
152 }
153 
154 MODULE_LICENSE("GPL");
155 
156 module_init(init_em_text);
157 module_exit(exit_em_text);
158 
159 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
160