[mirror_ubuntu-jammy-kernel.git] / net / dsa / tag_trailer.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * net/dsa/tag_trailer.c - Trailer tag format handling
 * Copyright (c) 2008-2009 Marvell Semiconductor
 */

#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/slab.h>

#include "dsa_priv.h"

static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct dsa_port *dp = dsa_slave_to_port(dev);
	u8 *trailer;

	trailer = skb_put(skb, 4);
	trailer[0] = 0x80;
	trailer[1] = 1 << dp->index;
	trailer[2] = 0x10;
	trailer[3] = 0x00;

	return skb;
}

static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev,
				   struct packet_type *pt)
{
	u8 *trailer;
	int source_port;

	if (skb_linearize(skb))
		return NULL;

	trailer = skb_tail_pointer(skb) - 4;
	if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
	    (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
		return NULL;

	source_port = trailer[1] & 7;

	skb->dev = dsa_master_find_slave(dev, 0, source_port);
	if (!skb->dev)
		return NULL;

	if (pskb_trim_rcsum(skb, skb->len - 4))
		return NULL;

	return skb;
}

static const struct dsa_device_ops trailer_netdev_ops = {
	.name	= "trailer",
	.proto	= DSA_TAG_PROTO_TRAILER,
	.xmit	= trailer_xmit,
	.rcv	= trailer_rcv,
	.needed_tailroom = 4,
};

MODULE_LICENSE("GPL");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER);

module_dsa_tag_driver(trailer_netdev_ops);
Commit	Line	Data
dfedd3b6	1	// SPDX-License-Identifier: GPL-2.0+
396138f0 LB	2	/*
396138f0 LB	3	* net/dsa/tag_trailer.c - Trailer tag format handling
e84665c9	4	* Copyright (c) 2008-2009 Marvell Semiconductor
396138f0 LB	5	*/
	6
	7	#include <linux/etherdevice.h>
	8	#include <linux/list.h>
5a0e3ad6	9	#include <linux/slab.h>
ea5dd34b	10
396138f0 LB	11	#include "dsa_priv.h"
396138f0 LB	12
4ed70ce9	13	static struct sk_buff trailer_xmit(struct sk_buff skb, struct net_device *dev)
396138f0	14	{
d945097b	15	struct dsa_port *dp = dsa_slave_to_port(dev);
396138f0 LB	16	u8 *trailer;
396138f0 LB	17
ef3f72fe	18	trailer = skb_put(skb, 4);
396138f0	19	trailer[0] = 0x80;
d945097b	20	trailer[1] = 1 << dp->index;
396138f0 LB	21	trailer[2] = 0x10;
	22	trailer[3] = 0x00;
	23
ef3f72fe	24	return skb;
396138f0 LB	25	}
396138f0 LB	26
a86d8bec	27	static struct sk_buff trailer_rcv(struct sk_buff skb, struct net_device *dev,
89e49506	28	struct packet_type *pt)
396138f0	29	{
396138f0 LB	30	u8 *trailer;
	31	int source_port;
	32
396138f0	33	if (skb_linearize(skb))
54709795	34	return NULL;
396138f0 LB	35
	36	trailer = skb_tail_pointer(skb) - 4;
	37	if (trailer[0] != 0x80 \|\| (trailer[1] & 0xf8) != 0x00 \|\|
fbd03513	38	(trailer[2] & 0xef) != 0x00 \|\| trailer[3] != 0x00)
54709795	39	return NULL;
396138f0 LB	40
396138f0 LB	41	source_port = trailer[1] & 7;
3775b1b7	42
2231c43b	43	skb->dev = dsa_master_find_slave(dev, 0, source_port);
3775b1b7	44	if (!skb->dev)
54709795	45	return NULL;
396138f0	46
349b71d6 ZJ	47	if (pskb_trim_rcsum(skb, skb->len - 4))
349b71d6 ZJ	48	return NULL;
396138f0	49
a86d8bec	50	return skb;
396138f0 LB	51	}
396138f0 LB	52
f81a43e8	53	static const struct dsa_device_ops trailer_netdev_ops = {
875138f8	54	.name = "trailer",
056eed2f	55	.proto = DSA_TAG_PROTO_TRAILER,
3e8a72d1 FF	56	.xmit = trailer_xmit,
3e8a72d1 FF	57	.rcv = trailer_rcv,
4e500251	58	.needed_tailroom = 4,
396138f0	59	};
0b42f033	60
f18bba50	61	MODULE_LICENSE("GPL");
0b42f033	62	MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER);
d3b8c049 AL	63
d3b8c049 AL	64	module_dsa_tag_driver(trailer_netdev_ops);