xref: /openbmc/linux/net/sched/em_nbyte.c (revision 22246614)
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 
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 
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 
65 static int __init init_em_nbyte(void)
66 {
67 	return tcf_em_register(&em_nbyte_ops);
68 }
69 
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