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(p: data, size: 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, 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 | |
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_LICENSE("GPL" ); |
72 | |
73 | module_init(init_em_nbyte); |
74 | module_exit(exit_em_nbyte); |
75 | |
76 | MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE); |
77 | |