1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/em_text.c Textsearch ematch
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8 #include <linux/slab.h>
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/skbuff.h>
14 #include <linux/textsearch.h>
15 #include <linux/tc_ematch/tc_em_text.h>
16 #include <net/pkt_cls.h>
17
18 struct text_match {
19 u16 from_offset;
20 u16 to_offset;
21 u8 from_layer;
22 u8 to_layer;
23 struct ts_config *config;
24 };
25
26 #define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
27
em_text_match(struct sk_buff * skb,struct tcf_ematch * m,struct tcf_pkt_info * info)28 static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
29 struct tcf_pkt_info *info)
30 {
31 struct text_match *tm = EM_TEXT_PRIV(m);
32 int from, to;
33
34 from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
35 from += tm->from_offset;
36
37 to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
38 to += tm->to_offset;
39
40 return skb_find_text(skb, from, to, tm->config) != UINT_MAX;
41 }
42
em_text_change(struct net * net,void * data,int len,struct tcf_ematch * m)43 static int em_text_change(struct net *net, void *data, int len,
44 struct tcf_ematch *m)
45 {
46 struct text_match *tm;
47 struct tcf_em_text *conf = data;
48 struct ts_config *ts_conf;
49 int flags = 0;
50
51 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
52 return -EINVAL;
53
54 if (conf->from_layer > conf->to_layer)
55 return -EINVAL;
56
57 if (conf->from_layer == conf->to_layer &&
58 conf->from_offset > conf->to_offset)
59 return -EINVAL;
60
61 retry:
62 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
63 conf->pattern_len, GFP_KERNEL, flags);
64
65 if (flags & TS_AUTOLOAD)
66 rtnl_lock();
67
68 if (IS_ERR(ts_conf)) {
69 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
70 rtnl_unlock();
71 flags |= TS_AUTOLOAD;
72 goto retry;
73 } else
74 return PTR_ERR(ts_conf);
75 } else if (flags & TS_AUTOLOAD) {
76 textsearch_destroy(ts_conf);
77 return -EAGAIN;
78 }
79
80 tm = kmalloc(sizeof(*tm), GFP_KERNEL);
81 if (tm == NULL) {
82 textsearch_destroy(ts_conf);
83 return -ENOBUFS;
84 }
85
86 tm->from_offset = conf->from_offset;
87 tm->to_offset = conf->to_offset;
88 tm->from_layer = conf->from_layer;
89 tm->to_layer = conf->to_layer;
90 tm->config = ts_conf;
91
92 m->datalen = sizeof(*tm);
93 m->data = (unsigned long) tm;
94
95 return 0;
96 }
97
em_text_destroy(struct tcf_ematch * m)98 static void em_text_destroy(struct tcf_ematch *m)
99 {
100 if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) {
101 textsearch_destroy(EM_TEXT_PRIV(m)->config);
102 kfree(EM_TEXT_PRIV(m));
103 }
104 }
105
em_text_dump(struct sk_buff * skb,struct tcf_ematch * m)106 static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
107 {
108 struct text_match *tm = EM_TEXT_PRIV(m);
109 struct tcf_em_text conf;
110
111 strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1);
112 conf.from_offset = tm->from_offset;
113 conf.to_offset = tm->to_offset;
114 conf.from_layer = tm->from_layer;
115 conf.to_layer = tm->to_layer;
116 conf.pattern_len = textsearch_get_pattern_len(tm->config);
117 conf.pad = 0;
118
119 if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0)
120 goto nla_put_failure;
121 if (nla_append(skb, conf.pattern_len,
122 textsearch_get_pattern(tm->config)) < 0)
123 goto nla_put_failure;
124 return 0;
125
126 nla_put_failure:
127 return -1;
128 }
129
130 static struct tcf_ematch_ops em_text_ops = {
131 .kind = TCF_EM_TEXT,
132 .change = em_text_change,
133 .match = em_text_match,
134 .destroy = em_text_destroy,
135 .dump = em_text_dump,
136 .owner = THIS_MODULE,
137 .link = LIST_HEAD_INIT(em_text_ops.link)
138 };
139
init_em_text(void)140 static int __init init_em_text(void)
141 {
142 return tcf_em_register(&em_text_ops);
143 }
144
exit_em_text(void)145 static void __exit exit_em_text(void)
146 {
147 tcf_em_unregister(&em_text_ops);
148 }
149
150 MODULE_DESCRIPTION("ematch classifier for embedded text in skbs");
151 MODULE_LICENSE("GPL");
152
153 module_init(init_em_text);
154 module_exit(exit_em_text);
155
156 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
157