2 * net/dsa/tag_trailer.c - Trailer tag format handling
3 * Copyright (c) 2008-2009 Marvell Semiconductor
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
11 #include <linux/etherdevice.h>
12 #include <linux/list.h>
13 #include <linux/slab.h>
17 static struct sk_buff
*trailer_xmit(struct sk_buff
*skb
, struct net_device
*dev
)
19 struct dsa_slave_priv
*p
= netdev_priv(dev
);
25 * We have to make sure that the trailer ends up as the very
26 * last 4 bytes of the packet. This means that we have to pad
27 * the packet to the minimum ethernet frame size, if necessary,
28 * before adding the trailer.
32 padlen
= 60 - skb
->len
;
34 nskb
= alloc_skb(NET_IP_ALIGN
+ skb
->len
+ padlen
+ 4, GFP_ATOMIC
);
37 skb_reserve(nskb
, NET_IP_ALIGN
);
39 skb_reset_mac_header(nskb
);
40 skb_set_network_header(nskb
, skb_network_header(skb
) - skb
->head
);
41 skb_set_transport_header(nskb
, skb_transport_header(skb
) - skb
->head
);
42 skb_copy_and_csum_dev(skb
, skb_put(nskb
, skb
->len
));
46 skb_put_zero(nskb
, padlen
);
49 trailer
= skb_put(nskb
, 4);
51 trailer
[1] = 1 << p
->dp
->index
;
58 static struct sk_buff
*trailer_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
59 struct packet_type
*pt
)
61 struct dsa_switch_tree
*dst
= dev
->dsa_ptr
;
62 struct dsa_port
*cpu_dp
= dsa_get_cpu_port(dst
);
63 struct dsa_switch
*ds
= cpu_dp
->ds
;
67 if (skb_linearize(skb
))
70 trailer
= skb_tail_pointer(skb
) - 4;
71 if (trailer
[0] != 0x80 || (trailer
[1] & 0xf8) != 0x00 ||
72 (trailer
[2] & 0xef) != 0x00 || trailer
[3] != 0x00)
75 source_port
= trailer
[1] & 7;
76 if (source_port
>= ds
->num_ports
|| !ds
->ports
[source_port
].netdev
)
79 if (unlikely(ds
->cpu_port_mask
& BIT(source_port
)))
82 if (pskb_trim_rcsum(skb
, skb
->len
- 4))
85 skb
->dev
= ds
->ports
[source_port
].netdev
;
90 const struct dsa_device_ops trailer_netdev_ops
= {