Linux kernel mirror (for testing)
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linux
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 u8 *trailer;
18
19 trailer = skb_put(skb, 4);
20 trailer[0] = 0x80;
21 trailer[1] = dsa_xmit_port_mask(skb, dev);
22 trailer[2] = 0x10;
23 trailer[3] = 0x00;
24
25 return skb;
26}
27
28static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev)
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_conduit_find_user(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_NAME,
55 .proto = DSA_TAG_PROTO_TRAILER,
56 .xmit = trailer_xmit,
57 .rcv = trailer_rcv,
58 .needed_tailroom = 4,
59};
60
61MODULE_DESCRIPTION("DSA tag driver for switches using a trailer tag");
62MODULE_LICENSE("GPL");
63MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER, TRAILER_NAME);
64
65module_dsa_tag_driver(trailer_netdev_ops);