GNU Linux-libre 4.19.211-gnu1
[releases.git] / net / sched / em_text.c
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
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
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
47 static 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
65 retry:
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
102 static 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
108 static 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
128 nla_put_failure:
129         return -1;
130 }
131
132 static 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
142 static int __init init_em_text(void)
143 {
144         return tcf_em_register(&em_text_ops);
145 }
146
147 static void __exit exit_em_text(void)
148 {
149         tcf_em_unregister(&em_text_ops);
150 }
151
152 MODULE_LICENSE("GPL");
153
154 module_init(init_em_text);
155 module_exit(exit_em_text);
156
157 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);