2 * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging
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>
19 static struct sk_buff
*dsa_xmit(struct sk_buff
*skb
, struct net_device
*dev
)
21 struct dsa_slave_priv
*p
= netdev_priv(dev
);
25 * Convert the outermost 802.1q tag to a DSA tag for tagged
26 * packets, or insert a DSA tag between the addresses and
27 * the ethertype field for untagged packets.
29 if (skb
->protocol
== htons(ETH_P_8021Q
)) {
30 if (skb_cow_head(skb
, 0) < 0)
34 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
36 dsa_header
= skb
->data
+ 2 * ETH_ALEN
;
37 dsa_header
[0] = 0x60 | p
->dp
->ds
->index
;
38 dsa_header
[1] = p
->dp
->index
<< 3;
41 * Move CFI field from byte 2 to byte 1.
43 if (dsa_header
[2] & 0x10) {
44 dsa_header
[1] |= 0x01;
45 dsa_header
[2] &= ~0x10;
48 if (skb_cow_head(skb
, DSA_HLEN
) < 0)
50 skb_push(skb
, DSA_HLEN
);
52 memmove(skb
->data
, skb
->data
+ DSA_HLEN
, 2 * ETH_ALEN
);
55 * Construct untagged FROM_CPU DSA tag.
57 dsa_header
= skb
->data
+ 2 * ETH_ALEN
;
58 dsa_header
[0] = 0x40 | p
->dp
->ds
->index
;
59 dsa_header
[1] = p
->dp
->index
<< 3;
71 static int dsa_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
72 struct packet_type
*pt
, struct net_device
*orig_dev
)
74 struct dsa_switch_tree
*dst
= dev
->dsa_ptr
;
75 struct dsa_switch
*ds
;
80 if (unlikely(dst
== NULL
))
83 skb
= skb_unshare(skb
, GFP_ATOMIC
);
87 if (unlikely(!pskb_may_pull(skb
, DSA_HLEN
)))
91 * The ethertype field is part of the DSA header.
93 dsa_header
= skb
->data
- 2;
96 * Check that frame type is either TO_CPU or FORWARD.
98 if ((dsa_header
[0] & 0xc0) != 0x00 && (dsa_header
[0] & 0xc0) != 0xc0)
102 * Determine source device and port.
104 source_device
= dsa_header
[0] & 0x1f;
105 source_port
= (dsa_header
[1] >> 3) & 0x1f;
108 * Check that the source device exists and that the source
109 * port is a registered DSA port.
111 if (source_device
>= DSA_MAX_SWITCHES
)
114 ds
= dst
->ds
[source_device
];
118 if (source_port
>= ds
->num_ports
|| !ds
->ports
[source_port
].netdev
)
122 * Convert the DSA header to an 802.1q header if the 'tagged'
123 * bit in the DSA header is set. If the 'tagged' bit is clear,
124 * delete the DSA header entirely.
126 if (dsa_header
[0] & 0x20) {
130 * Insert 802.1q ethertype and copy the VLAN-related
131 * fields, but clear the bit that will hold CFI (since
132 * DSA uses that bit location for another purpose).
134 new_header
[0] = (ETH_P_8021Q
>> 8) & 0xff;
135 new_header
[1] = ETH_P_8021Q
& 0xff;
136 new_header
[2] = dsa_header
[2] & ~0x10;
137 new_header
[3] = dsa_header
[3];
140 * Move CFI bit from its place in the DSA header to
141 * its 802.1q-designated place.
143 if (dsa_header
[1] & 0x01)
144 new_header
[2] |= 0x10;
147 * Update packet checksum if skb is CHECKSUM_COMPLETE.
149 if (skb
->ip_summed
== CHECKSUM_COMPLETE
) {
150 __wsum c
= skb
->csum
;
151 c
= csum_add(c
, csum_partial(new_header
+ 2, 2, 0));
152 c
= csum_sub(c
, csum_partial(dsa_header
+ 2, 2, 0));
156 memcpy(dsa_header
, new_header
, DSA_HLEN
);
159 * Remove DSA tag and update checksum.
161 skb_pull_rcsum(skb
, DSA_HLEN
);
162 memmove(skb
->data
- ETH_HLEN
,
163 skb
->data
- ETH_HLEN
- DSA_HLEN
,
167 skb
->dev
= ds
->ports
[source_port
].netdev
;
168 skb_push(skb
, ETH_HLEN
);
169 skb
->pkt_type
= PACKET_HOST
;
170 skb
->protocol
= eth_type_trans(skb
, skb
->dev
);
172 skb
->dev
->stats
.rx_packets
++;
173 skb
->dev
->stats
.rx_bytes
+= skb
->len
;
175 netif_receive_skb(skb
);
185 const struct dsa_device_ops dsa_netdev_ops
= {