/*
|
* net/dsa/tag_trailer.c - Trailer tag format handling
|
* Copyright (c) 2008-2009 Marvell Semiconductor
|
*
|
* This program is free software; you can redistribute it and/or modify
|
* it under the terms of the GNU General Public License as published by
|
* the Free Software Foundation; either version 2 of the License, or
|
* (at your option) any later version.
|
*/
|
|
#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);
|
struct sk_buff *nskb;
|
int padlen;
|
u8 *trailer;
|
|
/*
|
* We have to make sure that the trailer ends up as the very
|
* last 4 bytes of the packet. This means that we have to pad
|
* the packet to the minimum ethernet frame size, if necessary,
|
* before adding the trailer.
|
*/
|
padlen = 0;
|
if (skb->len < 60)
|
padlen = 60 - skb->len;
|
|
nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC);
|
if (!nskb)
|
return NULL;
|
skb_reserve(nskb, NET_IP_ALIGN);
|
|
skb_reset_mac_header(nskb);
|
skb_set_network_header(nskb, skb_network_header(skb) - skb->head);
|
skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head);
|
skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
|
consume_skb(skb);
|
|
if (padlen) {
|
skb_put_zero(nskb, padlen);
|
}
|
|
trailer = skb_put(nskb, 4);
|
trailer[0] = 0x80;
|
trailer[1] = 1 << dp->index;
|
trailer[2] = 0x10;
|
trailer[3] = 0x00;
|
|
return nskb;
|
}
|
|
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;
|
}
|
|
const struct dsa_device_ops trailer_netdev_ops = {
|
.xmit = trailer_xmit,
|
.rcv = trailer_rcv,
|
};
|
