1 // SPDX-License-Identifier: GPL-2.0+
3 * net/dsa/tag_trailer.c - Trailer tag format handling
4 * Copyright (c) 2008-2009 Marvell Semiconductor
7 #include <linux/etherdevice.h>
8 #include <linux/list.h>
9 #include <linux/slab.h>
13 #define TRAILER_NAME "trailer"
15 static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
17 struct dsa_port *dp = dsa_slave_to_port(dev);
20 trailer = skb_put(skb, 4);
22 trailer[1] = 1 << dp->index;
29 static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev)
34 if (skb_linearize(skb))
37 trailer = skb_tail_pointer(skb) - 4;
38 if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
39 (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
42 source_port = trailer[1] & 7;
44 skb->dev = dsa_master_find_slave(dev, 0, source_port);
48 if (pskb_trim_rcsum(skb, skb->len - 4))
54 static const struct dsa_device_ops trailer_netdev_ops = {
56 .proto = DSA_TAG_PROTO_TRAILER,
62 MODULE_LICENSE("GPL");
63 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER, TRAILER_NAME);
65 module_dsa_tag_driver(trailer_netdev_ops);