[linux-block.git] / net / sched / em_cmp.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/em_cmp.c	Simple packet data comparison ematch
 *
 * Authors:	Thomas Graf <tgraf@suug.ch>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/tc_ematch/tc_em_cmp.h>
#include <asm/unaligned.h>
#include <net/pkt_cls.h>

static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)
{
	return unlikely(cmp->flags & TCF_EM_CMP_TRANS);
}

static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em,
			struct tcf_pkt_info *info)
{
	struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data;
	unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off;
	u32 val = 0;

	if (!tcf_valid_offset(skb, ptr, cmp->align))
		return 0;

	switch (cmp->align) {
	case TCF_EM_ALIGN_U8:
		val = *ptr;
		break;

	case TCF_EM_ALIGN_U16:
		val = get_unaligned_be16(ptr);

		if (cmp_needs_transformation(cmp))
			val = be16_to_cpu(val);
		break;

	case TCF_EM_ALIGN_U32:
		/* Worth checking boundaries? The branching seems
		 * to get worse. Visit again.
		 */
		val = get_unaligned_be32(ptr);

		if (cmp_needs_transformation(cmp))
			val = be32_to_cpu(val);
		break;

	default:
		return 0;
	}

	if (cmp->mask)
		val &= cmp->mask;

	switch (cmp->opnd) {
	case TCF_EM_OPND_EQ:
		return val == cmp->val;
	case TCF_EM_OPND_LT:
		return val < cmp->val;
	case TCF_EM_OPND_GT:
		return val > cmp->val;
	}

	return 0;
}

static struct tcf_ematch_ops em_cmp_ops = {
	.kind	  = TCF_EM_CMP,
	.datalen  = sizeof(struct tcf_em_cmp),
	.match	  = em_cmp_match,
	.owner	  = THIS_MODULE,
	.link	  = LIST_HEAD_INIT(em_cmp_ops.link)
};

static int __init init_em_cmp(void)
{
	return tcf_em_register(&em_cmp_ops);
}

static void __exit exit_em_cmp(void)
{
	tcf_em_unregister(&em_cmp_ops);
}

MODULE_DESCRIPTION("ematch classifier for basic data types(8/16/32 bit) against skb data");
MODULE_LICENSE("GPL");

module_init(init_em_cmp);
module_exit(exit_em_cmp);

MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* net/sched/em_cmp.c Simple packet data comparison ematch
	4	*
1da177e4 LT	5	* Authors: Thomas Graf <tgraf@suug.ch>
	6	*/
	7
1da177e4 LT	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>
d48abfec	13	#include <asm/unaligned.h>
1da177e4 LT	14	#include <net/pkt_cls.h>
	15
	16	static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)
	17	{
	18	return unlikely(cmp->flags & TCF_EM_CMP_TRANS);
	19	}
	20
	21	static 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) {
cc7ec456 ED	32	case TCF_EM_ALIGN_U8:
	33	val = *ptr;
	34	break;
1da177e4	35
cc7ec456 ED	36	case TCF_EM_ALIGN_U16:
cc7ec456 ED	37	val = get_unaligned_be16(ptr);
1da177e4	38
cc7ec456 ED	39	if (cmp_needs_transformation(cmp))
	40	val = be16_to_cpu(val);
	41	break;
1da177e4	42
cc7ec456	43	case TCF_EM_ALIGN_U32:
e5a4b17d	44	/* Worth checking boundaries? The branching seems
cc7ec456 ED	45	* to get worse. Visit again.
	46	*/
	47	val = get_unaligned_be32(ptr);
1da177e4	48
cc7ec456 ED	49	if (cmp_needs_transformation(cmp))
	50	val = be32_to_cpu(val);
	51	break;
1da177e4	52
cc7ec456 ED	53	default:
cc7ec456 ED	54	return 0;
1da177e4 LT	55	}
	56
	57	if (cmp->mask)
	58	val &= cmp->mask;
	59
	60	switch (cmp->opnd) {
cc7ec456 ED	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;
1da177e4 LT	67	}
	68
	69	return 0;
	70	}
	71
	72	static 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
	80	static int __init init_em_cmp(void)
	81	{
	82	return tcf_em_register(&em_cmp_ops);
	83	}
	84
10297b99	85	static void __exit exit_em_cmp(void)
1da177e4 LT	86	{
	87	tcf_em_unregister(&em_cmp_ops);
	88	}
	89
a46c31bf	90	MODULE_DESCRIPTION("ematch classifier for basic data types(8/16/32 bit) against skb data");
1da177e4 LT	91	MODULE_LICENSE("GPL");
	92
	93	module_init(init_em_cmp);
	94	module_exit(exit_em_cmp);
	95
db3d99c0	96	MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);