1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
/*
* net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging
* 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"
#define DSA_HLEN 4
static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
u8 *dsa_header;
/*
* Convert the outermost 802.1q tag to a DSA tag for tagged
* packets, or insert a DSA tag between the addresses and
* the ethertype field for untagged packets.
*/
if (skb->protocol == htons(ETH_P_8021Q)) {
if (skb_cow_head(skb, 0) < 0)
return NULL;
/*
* Construct tagged FROM_CPU DSA tag from 802.1q tag.
*/
dsa_header = skb->data + 2 * ETH_ALEN;
dsa_header[0] = 0x60 | dp->ds->index;
dsa_header[1] = dp->index << 3;
/*
* Move CFI field from byte 2 to byte 1.
*/
if (dsa_header[2] & 0x10) {
dsa_header[1] |= 0x01;
dsa_header[2] &= ~0x10;
}
} else {
if (skb_cow_head(skb, DSA_HLEN) < 0)
return NULL;
skb_push(skb, DSA_HLEN);
memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
/*
* Construct untagged FROM_CPU DSA tag.
*/
dsa_header = skb->data + 2 * ETH_ALEN;
dsa_header[0] = 0x40 | dp->ds->index;
dsa_header[1] = dp->index << 3;
dsa_header[2] = 0x00;
dsa_header[3] = 0x00;
}
return skb;
}
static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt)
{
u8 *dsa_header;
int source_device;
int source_port;
if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
return NULL;
/*
* The ethertype field is part of the DSA header.
*/
dsa_header = skb->data - 2;
/*
* Check that frame type is either TO_CPU or FORWARD.
*/
if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0)
return NULL;
/*
* Determine source device and port.
*/
source_device = dsa_header[0] & 0x1f;
source_port = (dsa_header[1] >> 3) & 0x1f;
skb->dev = dsa_master_find_slave(dev, source_device, source_port);
if (!skb->dev)
return NULL;
/*
* Convert the DSA header to an 802.1q header if the 'tagged'
* bit in the DSA header is set. If the 'tagged' bit is clear,
* delete the DSA header entirely.
*/
if (dsa_header[0] & 0x20) {
u8 new_header[4];
/*
* Insert 802.1q ethertype and copy the VLAN-related
* fields, but clear the bit that will hold CFI (since
* DSA uses that bit location for another purpose).
*/
new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
new_header[1] = ETH_P_8021Q & 0xff;
new_header[2] = dsa_header[2] & ~0x10;
new_header[3] = dsa_header[3];
/*
* Move CFI bit from its place in the DSA header to
* its 802.1q-designated place.
*/
if (dsa_header[1] & 0x01)
new_header[2] |= 0x10;
/*
* Update packet checksum if skb is CHECKSUM_COMPLETE.
*/
if (skb->ip_summed == CHECKSUM_COMPLETE) {
__wsum c = skb->csum;
c = csum_add(c, csum_partial(new_header + 2, 2, 0));
c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0));
skb->csum = c;
}
memcpy(dsa_header, new_header, DSA_HLEN);
} else {
/*
* Remove DSA tag and update checksum.
*/
skb_pull_rcsum(skb, DSA_HLEN);
memmove(skb->data - ETH_HLEN,
skb->data - ETH_HLEN - DSA_HLEN,
2 * ETH_ALEN);
}
skb->offload_fwd_mark = 1;
return skb;
}
static int dsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
int *offset)
{
*offset = 4;
*proto = ((__be16 *)skb->data)[1];
return 0;
}
const struct dsa_device_ops dsa_netdev_ops = {
.xmit = dsa_xmit,
.rcv = dsa_rcv,
.flow_dissect = dsa_tag_flow_dissect,
.overhead = DSA_HLEN,
};
|
