// SPDX-License-Identifier: GPL-2.0+
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/*
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* net/dsa/tag_trailer.c - Trailer tag format handling
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* Copyright (c) 2008-2009 Marvell Semiconductor
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*/
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#include <linux/etherdevice.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include "dsa_priv.h"
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static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct dsa_port *dp = dsa_slave_to_port(dev);
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u8 *trailer;
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trailer = skb_put(skb, 4);
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trailer[0] = 0x80;
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trailer[1] = 1 << dp->index;
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trailer[2] = 0x10;
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trailer[3] = 0x00;
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return skb;
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}
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static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pt)
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{
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u8 *trailer;
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int source_port;
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if (skb_linearize(skb))
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return NULL;
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trailer = skb_tail_pointer(skb) - 4;
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if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
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(trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
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return NULL;
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source_port = trailer[1] & 7;
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skb->dev = dsa_master_find_slave(dev, 0, source_port);
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if (!skb->dev)
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return NULL;
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if (pskb_trim_rcsum(skb, skb->len - 4))
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return NULL;
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return skb;
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}
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static const struct dsa_device_ops trailer_netdev_ops = {
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.name = "trailer",
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.proto = DSA_TAG_PROTO_TRAILER,
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.xmit = trailer_xmit,
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.rcv = trailer_rcv,
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.overhead = 4,
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.tail_tag = true,
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};
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER);
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module_dsa_tag_driver(trailer_netdev_ops);
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