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91da11f8 LB |
1 | /* |
2 | * net/dsa/tag_edsa.c - Ethertype DSA tagging | |
e84665c9 | 3 | * Copyright (c) 2008-2009 Marvell Semiconductor |
91da11f8 LB |
4 | * |
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. | |
9 | */ | |
10 | ||
11 | #include <linux/etherdevice.h> | |
12 | #include <linux/list.h> | |
5a0e3ad6 | 13 | #include <linux/slab.h> |
ea5dd34b | 14 | |
91da11f8 LB |
15 | #include "dsa_priv.h" |
16 | ||
17 | #define DSA_HLEN 4 | |
18 | #define EDSA_HLEN 8 | |
19 | ||
4ed70ce9 | 20 | static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev) |
91da11f8 | 21 | { |
d945097b | 22 | struct dsa_port *dp = dsa_slave_to_port(dev); |
91da11f8 LB |
23 | u8 *edsa_header; |
24 | ||
91da11f8 LB |
25 | /* |
26 | * Convert the outermost 802.1q tag to a DSA tag and prepend | |
27 | * a DSA ethertype field is the packet is tagged, or insert | |
28 | * a DSA ethertype plus DSA tag between the addresses and the | |
29 | * current ethertype field if the packet is untagged. | |
30 | */ | |
31 | if (skb->protocol == htons(ETH_P_8021Q)) { | |
32 | if (skb_cow_head(skb, DSA_HLEN) < 0) | |
fe47d563 | 33 | return NULL; |
91da11f8 LB |
34 | skb_push(skb, DSA_HLEN); |
35 | ||
36 | memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); | |
37 | ||
38 | /* | |
39 | * Construct tagged FROM_CPU DSA tag from 802.1q tag. | |
40 | */ | |
41 | edsa_header = skb->data + 2 * ETH_ALEN; | |
42 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; | |
43 | edsa_header[1] = ETH_P_EDSA & 0xff; | |
44 | edsa_header[2] = 0x00; | |
45 | edsa_header[3] = 0x00; | |
d945097b VD |
46 | edsa_header[4] = 0x60 | dp->ds->index; |
47 | edsa_header[5] = dp->index << 3; | |
91da11f8 LB |
48 | |
49 | /* | |
50 | * Move CFI field from byte 6 to byte 5. | |
51 | */ | |
52 | if (edsa_header[6] & 0x10) { | |
53 | edsa_header[5] |= 0x01; | |
54 | edsa_header[6] &= ~0x10; | |
55 | } | |
56 | } else { | |
57 | if (skb_cow_head(skb, EDSA_HLEN) < 0) | |
fe47d563 | 58 | return NULL; |
91da11f8 LB |
59 | skb_push(skb, EDSA_HLEN); |
60 | ||
61 | memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN); | |
62 | ||
63 | /* | |
64 | * Construct untagged FROM_CPU DSA tag. | |
65 | */ | |
66 | edsa_header = skb->data + 2 * ETH_ALEN; | |
67 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; | |
68 | edsa_header[1] = ETH_P_EDSA & 0xff; | |
69 | edsa_header[2] = 0x00; | |
70 | edsa_header[3] = 0x00; | |
d945097b VD |
71 | edsa_header[4] = 0x40 | dp->ds->index; |
72 | edsa_header[5] = dp->index << 3; | |
91da11f8 LB |
73 | edsa_header[6] = 0x00; |
74 | edsa_header[7] = 0x00; | |
75 | } | |
76 | ||
4ed70ce9 | 77 | return skb; |
91da11f8 LB |
78 | } |
79 | ||
a86d8bec | 80 | static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev, |
89e49506 | 81 | struct packet_type *pt) |
91da11f8 | 82 | { |
91da11f8 | 83 | u8 *edsa_header; |
e84665c9 | 84 | int source_device; |
91da11f8 LB |
85 | int source_port; |
86 | ||
91da11f8 | 87 | if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) |
54709795 | 88 | return NULL; |
91da11f8 LB |
89 | |
90 | /* | |
91 | * Skip the two null bytes after the ethertype. | |
92 | */ | |
93 | edsa_header = skb->data + 2; | |
94 | ||
95 | /* | |
e84665c9 | 96 | * Check that frame type is either TO_CPU or FORWARD. |
91da11f8 | 97 | */ |
e84665c9 | 98 | if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0) |
54709795 | 99 | return NULL; |
91da11f8 LB |
100 | |
101 | /* | |
e84665c9 | 102 | * Determine source device and port. |
91da11f8 | 103 | */ |
e84665c9 | 104 | source_device = edsa_header[0] & 0x1f; |
91da11f8 | 105 | source_port = (edsa_header[1] >> 3) & 0x1f; |
e84665c9 | 106 | |
2231c43b | 107 | skb->dev = dsa_master_find_slave(dev, source_device, source_port); |
3775b1b7 | 108 | if (!skb->dev) |
54709795 | 109 | return NULL; |
91da11f8 LB |
110 | |
111 | /* | |
112 | * If the 'tagged' bit is set, convert the DSA tag to a 802.1q | |
113 | * tag and delete the ethertype part. If the 'tagged' bit is | |
114 | * clear, delete the ethertype and the DSA tag parts. | |
115 | */ | |
116 | if (edsa_header[0] & 0x20) { | |
117 | u8 new_header[4]; | |
118 | ||
119 | /* | |
120 | * Insert 802.1q ethertype and copy the VLAN-related | |
121 | * fields, but clear the bit that will hold CFI (since | |
122 | * DSA uses that bit location for another purpose). | |
123 | */ | |
124 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; | |
125 | new_header[1] = ETH_P_8021Q & 0xff; | |
126 | new_header[2] = edsa_header[2] & ~0x10; | |
127 | new_header[3] = edsa_header[3]; | |
128 | ||
129 | /* | |
130 | * Move CFI bit from its place in the DSA header to | |
131 | * its 802.1q-designated place. | |
132 | */ | |
133 | if (edsa_header[1] & 0x01) | |
134 | new_header[2] |= 0x10; | |
135 | ||
136 | skb_pull_rcsum(skb, DSA_HLEN); | |
137 | ||
138 | /* | |
139 | * Update packet checksum if skb is CHECKSUM_COMPLETE. | |
140 | */ | |
141 | if (skb->ip_summed == CHECKSUM_COMPLETE) { | |
142 | __wsum c = skb->csum; | |
143 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); | |
144 | c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0)); | |
145 | skb->csum = c; | |
146 | } | |
147 | ||
148 | memcpy(edsa_header, new_header, DSA_HLEN); | |
149 | ||
150 | memmove(skb->data - ETH_HLEN, | |
151 | skb->data - ETH_HLEN - DSA_HLEN, | |
152 | 2 * ETH_ALEN); | |
153 | } else { | |
154 | /* | |
155 | * Remove DSA tag and update checksum. | |
156 | */ | |
157 | skb_pull_rcsum(skb, EDSA_HLEN); | |
158 | memmove(skb->data - ETH_HLEN, | |
159 | skb->data - ETH_HLEN - EDSA_HLEN, | |
160 | 2 * ETH_ALEN); | |
161 | } | |
162 | ||
13edbdb6 AL |
163 | skb->offload_fwd_mark = 1; |
164 | ||
a86d8bec | 165 | return skb; |
91da11f8 LB |
166 | } |
167 | ||
3e8a72d1 FF |
168 | const struct dsa_device_ops edsa_netdev_ops = { |
169 | .xmit = edsa_xmit, | |
170 | .rcv = edsa_rcv, | |
91da11f8 | 171 | }; |