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
17struct nbyte_data {
18 struct tcf_em_nbyte hdr;
19 char pattern[];
20};
21
22static 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(p: data, size: em->datalen, GFP_KERNEL);
33 if (em->data == 0UL)
34 return -ENOMEM;
35
36 return 0;
37}
38
39static 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, layer: nbyte->hdr.layer);
44
45 ptr += nbyte->hdr.off;
46
47 if (!tcf_valid_offset(skb, ptr, len: nbyte->hdr.len))
48 return 0;
49
50 return !memcmp(p: ptr, q: nbyte->pattern, size: nbyte->hdr.len);
51}
52
53static 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
61static int __init init_em_nbyte(void)
62{
63 return tcf_em_register(&em_nbyte_ops);
64}
65
66static void __exit exit_em_nbyte(void)
67{
68 tcf_em_unregister(&em_nbyte_ops);
69}
70
71MODULE_LICENSE("GPL");
72
73module_init(init_em_nbyte);
74module_exit(exit_em_nbyte);
75
76MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE);
77

source code of linux/net/sched/em_nbyte.c