1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/em_nbyte.c N-Byte ematch
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8 #include <linux/gfp.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/tc_ematch/tc_em_nbyte.h>
15 #include <net/pkt_cls.h>
16
17 struct nbyte_data {
18 struct tcf_em_nbyte hdr;
19 char pattern[];
20 };
21
22 static int em_nbyte_change(struct net *net, void *data, int data_len,
23 struct tcf_ematch *em)
24 {
25 struct tcf_em_nbyte *nbyte = data;
26
27 if (data_len < sizeof(*nbyte) ||
28 data_len < (sizeof(*nbyte) + nbyte->len))
29 return -EINVAL;
30
31 em->datalen = sizeof(*nbyte) + nbyte->len;
32 em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
33 if (em->data == 0UL)
34 return -ENOMEM;
35
36 return 0;
37 }
38
39 static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em,
40 struct tcf_pkt_info *info)
41 {
42 struct nbyte_data *nbyte = (struct nbyte_data *) em->data;
43 unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer);
44
45 ptr += nbyte->hdr.off;
46
47 if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len))
48 return 0;
49
50 return !memcmp(ptr, nbyte->pattern, nbyte->hdr.len);
51 }
52
53 static struct tcf_ematch_ops em_nbyte_ops = {
54 .kind = TCF_EM_NBYTE,
55 .change = em_nbyte_change,
56 .match = em_nbyte_match,
57 .owner = THIS_MODULE,
58 .link = LIST_HEAD_INIT(em_nbyte_ops.link)
59 };
60
61 static int __init init_em_nbyte(void)
62 {
63 return tcf_em_register(&em_nbyte_ops);
64 }
65
66 static void __exit exit_em_nbyte(void)
67 {
68 tcf_em_unregister(&em_nbyte_ops);
69 }
70
71 MODULE_DESCRIPTION("ematch classifier for arbitrary skb multi-bytes");
72 MODULE_LICENSE("GPL");
73
74 module_init(init_em_nbyte);
75 module_exit(exit_em_nbyte);
76
77 MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE);
78
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