1/*
 2 * net/sched/em_cmp.c	Simple packet data comparison 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/skbuff.h>
16#include <linux/tc_ematch/tc_em_cmp.h>
17#include <asm/unaligned.h>
18#include <net/pkt_cls.h>
19
20static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)
21{
22	return unlikely(cmp->flags & TCF_EM_CMP_TRANS);
23}
24
25static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em,
26			struct tcf_pkt_info *info)
27{
28	struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data;
29	unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off;
30	u32 val = 0;
31
32	if (!tcf_valid_offset(skb, ptr, cmp->align))
33		return 0;
34
35	switch (cmp->align) {
36	case TCF_EM_ALIGN_U8:
37		val = *ptr;
38		break;
39
40	case TCF_EM_ALIGN_U16:
41		val = get_unaligned_be16(ptr);
42
43		if (cmp_needs_transformation(cmp))
44			val = be16_to_cpu(val);
45		break;
46
47	case TCF_EM_ALIGN_U32:
48		/* Worth checking boundries? The branching seems
49		 * to get worse. Visit again.
50		 */
51		val = get_unaligned_be32(ptr);
52
53		if (cmp_needs_transformation(cmp))
54			val = be32_to_cpu(val);
55		break;
56
57	default:
58		return 0;
59	}
60
61	if (cmp->mask)
62		val &= cmp->mask;
63
64	switch (cmp->opnd) {
65	case TCF_EM_OPND_EQ:
66		return val == cmp->val;
67	case TCF_EM_OPND_LT:
68		return val < cmp->val;
69	case TCF_EM_OPND_GT:
70		return val > cmp->val;
71	}
72
73	return 0;
74}
75
76static struct tcf_ematch_ops em_cmp_ops = {
77	.kind	  = TCF_EM_CMP,
78	.datalen  = sizeof(struct tcf_em_cmp),
79	.match	  = em_cmp_match,
80	.owner	  = THIS_MODULE,
81	.link	  = LIST_HEAD_INIT(em_cmp_ops.link)
82};
83
84static int __init init_em_cmp(void)
85{
86	return tcf_em_register(&em_cmp_ops);
87}
88
89static void __exit exit_em_cmp(void)
90{
91	tcf_em_unregister(&em_cmp_ops);
92}
93
94MODULE_LICENSE("GPL");
95
96module_init(init_em_cmp);
97module_exit(exit_em_cmp);
98
99MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);

 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * net/sched/em_cmp.c	Simple packet data comparison ematch
 
 
 
 
 
 4 *
 5 * Authors:	Thomas Graf <tgraf@suug.ch>
 6 */
 7
 8#include <linux/module.h>
 9#include <linux/types.h>
10#include <linux/kernel.h>
11#include <linux/skbuff.h>
12#include <linux/tc_ematch/tc_em_cmp.h>
13#include <asm/unaligned.h>
14#include <net/pkt_cls.h>
15
16static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)
17{
18	return unlikely(cmp->flags & TCF_EM_CMP_TRANS);
19}
20
21static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em,
22			struct tcf_pkt_info *info)
23{
24	struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data;
25	unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off;
26	u32 val = 0;
27
28	if (!tcf_valid_offset(skb, ptr, cmp->align))
29		return 0;
30
31	switch (cmp->align) {
32	case TCF_EM_ALIGN_U8:
33		val = *ptr;
34		break;
35
36	case TCF_EM_ALIGN_U16:
37		val = get_unaligned_be16(ptr);
38
39		if (cmp_needs_transformation(cmp))
40			val = be16_to_cpu(val);
41		break;
42
43	case TCF_EM_ALIGN_U32:
44		/* Worth checking boundries? The branching seems
45		 * to get worse. Visit again.
46		 */
47		val = get_unaligned_be32(ptr);
48
49		if (cmp_needs_transformation(cmp))
50			val = be32_to_cpu(val);
51		break;
52
53	default:
54		return 0;
55	}
56
57	if (cmp->mask)
58		val &= cmp->mask;
59
60	switch (cmp->opnd) {
61	case TCF_EM_OPND_EQ:
62		return val == cmp->val;
63	case TCF_EM_OPND_LT:
64		return val < cmp->val;
65	case TCF_EM_OPND_GT:
66		return val > cmp->val;
67	}
68
69	return 0;
70}
71
72static struct tcf_ematch_ops em_cmp_ops = {
73	.kind	  = TCF_EM_CMP,
74	.datalen  = sizeof(struct tcf_em_cmp),
75	.match	  = em_cmp_match,
76	.owner	  = THIS_MODULE,
77	.link	  = LIST_HEAD_INIT(em_cmp_ops.link)
78};
79
80static int __init init_em_cmp(void)
81{
82	return tcf_em_register(&em_cmp_ops);
83}
84
85static void __exit exit_em_cmp(void)
86{
87	tcf_em_unregister(&em_cmp_ops);
88}
89
90MODULE_LICENSE("GPL");
91
92module_init(init_em_cmp);
93module_exit(exit_em_cmp);
94
95MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);