1// SPDX-License-Identifier: GPL-2.0+
 2/*
 3 * net/dsa/tag_trailer.c - Trailer tag format handling
 4 * Copyright (c) 2008-2009 Marvell Semiconductor
 5 */
 6
 7#include <linux/etherdevice.h>
 8#include <linux/list.h>
 9#include <linux/slab.h>
10
11#include "tag.h"
12
13#define TRAILER_NAME "trailer"
14
15static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
16{
17	struct dsa_port *dp = dsa_user_to_port(dev);
18	u8 *trailer;
19
20	trailer = skb_put(skb, 4);
21	trailer[0] = 0x80;
22	trailer[1] = 1 << dp->index;
23	trailer[2] = 0x10;
24	trailer[3] = 0x00;
25
26	return skb;
27}
28
29static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev)
 
30{
31	u8 *trailer;
32	int source_port;
33
34	if (skb_linearize(skb))
35		return NULL;
36
37	trailer = skb_tail_pointer(skb) - 4;
38	if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
39	    (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
40		return NULL;
41
42	source_port = trailer[1] & 7;
43
44	skb->dev = dsa_conduit_find_user(dev, 0, source_port);
45	if (!skb->dev)
46		return NULL;
47
48	if (pskb_trim_rcsum(skb, skb->len - 4))
49		return NULL;
50
51	return skb;
52}
53
54static const struct dsa_device_ops trailer_netdev_ops = {
55	.name	= TRAILER_NAME,
56	.proto	= DSA_TAG_PROTO_TRAILER,
57	.xmit	= trailer_xmit,
58	.rcv	= trailer_rcv,
59	.needed_tailroom = 4,
60};
61
62MODULE_DESCRIPTION("DSA tag driver for switches using a trailer tag");
63MODULE_LICENSE("GPL");
64MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER, TRAILER_NAME);
65
66module_dsa_tag_driver(trailer_netdev_ops);

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