Commit | Line | Data |
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cf85d08f LB |
1 | /* |
2 | * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging | |
e84665c9 | 3 | * Copyright (c) 2008-2009 Marvell Semiconductor |
cf85d08f 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 | |
cf85d08f LB |
15 | #include "dsa_priv.h" |
16 | ||
17 | #define DSA_HLEN 4 | |
18 | ||
4ed70ce9 | 19 | static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) |
cf85d08f LB |
20 | { |
21 | struct dsa_slave_priv *p = netdev_priv(dev); | |
22 | u8 *dsa_header; | |
23 | ||
cf85d08f LB |
24 | /* |
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. | |
28 | */ | |
29 | if (skb->protocol == htons(ETH_P_8021Q)) { | |
30 | if (skb_cow_head(skb, 0) < 0) | |
31 | goto out_free; | |
32 | ||
33 | /* | |
34 | * Construct tagged FROM_CPU DSA tag from 802.1q tag. | |
35 | */ | |
36 | dsa_header = skb->data + 2 * ETH_ALEN; | |
afdcf151 VD |
37 | dsa_header[0] = 0x60 | p->dp->ds->index; |
38 | dsa_header[1] = p->dp->index << 3; | |
cf85d08f LB |
39 | |
40 | /* | |
41 | * Move CFI field from byte 2 to byte 1. | |
42 | */ | |
43 | if (dsa_header[2] & 0x10) { | |
44 | dsa_header[1] |= 0x01; | |
45 | dsa_header[2] &= ~0x10; | |
46 | } | |
47 | } else { | |
48 | if (skb_cow_head(skb, DSA_HLEN) < 0) | |
49 | goto out_free; | |
50 | skb_push(skb, DSA_HLEN); | |
51 | ||
52 | memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); | |
53 | ||
54 | /* | |
55 | * Construct untagged FROM_CPU DSA tag. | |
56 | */ | |
57 | dsa_header = skb->data + 2 * ETH_ALEN; | |
afdcf151 VD |
58 | dsa_header[0] = 0x40 | p->dp->ds->index; |
59 | dsa_header[1] = p->dp->index << 3; | |
cf85d08f LB |
60 | dsa_header[2] = 0x00; |
61 | dsa_header[3] = 0x00; | |
62 | } | |
63 | ||
4ed70ce9 | 64 | return skb; |
cf85d08f LB |
65 | |
66 | out_free: | |
67 | kfree_skb(skb); | |
4ed70ce9 | 68 | return NULL; |
cf85d08f LB |
69 | } |
70 | ||
a86d8bec FF |
71 | static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev, |
72 | struct packet_type *pt, | |
73 | struct net_device *orig_dev) | |
cf85d08f | 74 | { |
e84665c9 LB |
75 | struct dsa_switch_tree *dst = dev->dsa_ptr; |
76 | struct dsa_switch *ds; | |
cf85d08f | 77 | u8 *dsa_header; |
e84665c9 | 78 | int source_device; |
cf85d08f LB |
79 | int source_port; |
80 | ||
cf85d08f | 81 | if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) |
54709795 | 82 | return NULL; |
cf85d08f LB |
83 | |
84 | /* | |
85 | * The ethertype field is part of the DSA header. | |
86 | */ | |
87 | dsa_header = skb->data - 2; | |
88 | ||
89 | /* | |
e84665c9 | 90 | * Check that frame type is either TO_CPU or FORWARD. |
cf85d08f | 91 | */ |
e84665c9 | 92 | if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) |
54709795 | 93 | return NULL; |
cf85d08f LB |
94 | |
95 | /* | |
e84665c9 | 96 | * Determine source device and port. |
cf85d08f | 97 | */ |
e84665c9 | 98 | source_device = dsa_header[0] & 0x1f; |
cf85d08f | 99 | source_port = (dsa_header[1] >> 3) & 0x1f; |
e84665c9 LB |
100 | |
101 | /* | |
102 | * Check that the source device exists and that the source | |
103 | * port is a registered DSA port. | |
104 | */ | |
149cafd7 | 105 | if (source_device >= DSA_MAX_SWITCHES) |
54709795 | 106 | return NULL; |
149cafd7 | 107 | |
e84665c9 | 108 | ds = dst->ds[source_device]; |
149cafd7 | 109 | if (!ds) |
54709795 | 110 | return NULL; |
149cafd7 | 111 | |
26895e29 | 112 | if (source_port >= ds->num_ports || !ds->ports[source_port].netdev) |
54709795 | 113 | return NULL; |
cf85d08f LB |
114 | |
115 | /* | |
116 | * Convert the DSA header to an 802.1q header if the 'tagged' | |
117 | * bit in the DSA header is set. If the 'tagged' bit is clear, | |
118 | * delete the DSA header entirely. | |
119 | */ | |
120 | if (dsa_header[0] & 0x20) { | |
121 | u8 new_header[4]; | |
122 | ||
123 | /* | |
124 | * Insert 802.1q ethertype and copy the VLAN-related | |
125 | * fields, but clear the bit that will hold CFI (since | |
126 | * DSA uses that bit location for another purpose). | |
127 | */ | |
128 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; | |
129 | new_header[1] = ETH_P_8021Q & 0xff; | |
130 | new_header[2] = dsa_header[2] & ~0x10; | |
131 | new_header[3] = dsa_header[3]; | |
132 | ||
133 | /* | |
134 | * Move CFI bit from its place in the DSA header to | |
135 | * its 802.1q-designated place. | |
136 | */ | |
137 | if (dsa_header[1] & 0x01) | |
138 | new_header[2] |= 0x10; | |
139 | ||
140 | /* | |
141 | * Update packet checksum if skb is CHECKSUM_COMPLETE. | |
142 | */ | |
143 | if (skb->ip_summed == CHECKSUM_COMPLETE) { | |
144 | __wsum c = skb->csum; | |
145 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); | |
146 | c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); | |
147 | skb->csum = c; | |
148 | } | |
149 | ||
150 | memcpy(dsa_header, new_header, DSA_HLEN); | |
151 | } else { | |
152 | /* | |
153 | * Remove DSA tag and update checksum. | |
154 | */ | |
155 | skb_pull_rcsum(skb, DSA_HLEN); | |
156 | memmove(skb->data - ETH_HLEN, | |
157 | skb->data - ETH_HLEN - DSA_HLEN, | |
158 | 2 * ETH_ALEN); | |
159 | } | |
160 | ||
c8b09808 | 161 | skb->dev = ds->ports[source_port].netdev; |
cf85d08f | 162 | |
a86d8bec | 163 | return skb; |
cf85d08f LB |
164 | } |
165 | ||
3e8a72d1 FF |
166 | const struct dsa_device_ops dsa_netdev_ops = { |
167 | .xmit = dsa_xmit, | |
168 | .rcv = dsa_rcv, | |
cf85d08f | 169 | }; |