1 /*
2 * net/sched/em_nbyte.c N-Byte 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/module.h>
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/string.h>
16 #include <linux/skbuff.h>
17 #include <linux/tc_ematch/tc_em_nbyte.h>
18 #include <net/pkt_cls.h>
19
20 struct nbyte_data
21 {
22 struct tcf_em_nbyte hdr;
23 char pattern[0];
24 };
25
em_nbyte_change(struct tcf_proto * tp,void * data,int data_len,struct tcf_ematch * em)26 static int em_nbyte_change(struct tcf_proto *tp, void *data, int data_len,
27 struct tcf_ematch *em)
28 {
29 struct tcf_em_nbyte *nbyte = data;
30
31 if (data_len < sizeof(*nbyte) ||
32 data_len < (sizeof(*nbyte) + nbyte->len))
33 return -EINVAL;
34
35 em->datalen = sizeof(*nbyte) + nbyte->len;
36 em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
37 if (em->data == 0UL)
38 return -ENOBUFS;
39
40 return 0;
41 }
42
em_nbyte_match(struct sk_buff * skb,struct tcf_ematch * em,struct tcf_pkt_info * info)43 static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em,
44 struct tcf_pkt_info *info)
45 {
46 struct nbyte_data *nbyte = (struct nbyte_data *) em->data;
47 unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer);
48
49 ptr += nbyte->hdr.off;
50
51 if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len))
52 return 0;
53
54 return !memcmp(ptr + nbyte->hdr.off, nbyte->pattern, nbyte->hdr.len);
55 }
56
57 static struct tcf_ematch_ops em_nbyte_ops = {
58 .kind = TCF_EM_NBYTE,
59 .change = em_nbyte_change,
60 .match = em_nbyte_match,
61 .owner = THIS_MODULE,
62 .link = LIST_HEAD_INIT(em_nbyte_ops.link)
63 };
64
init_em_nbyte(void)65 static int __init init_em_nbyte(void)
66 {
67 return tcf_em_register(&em_nbyte_ops);
68 }
69
exit_em_nbyte(void)70 static void __exit exit_em_nbyte(void)
71 {
72 tcf_em_unregister(&em_nbyte_ops);
73 }
74
75 MODULE_LICENSE("GPL");
76
77 module_init(init_em_nbyte);
78 module_exit(exit_em_nbyte);
79
80 MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE);
81