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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> |
cf85d08f LB |
14 | #include "dsa_priv.h" |
15 | ||
16 | #define DSA_HLEN 4 | |
17 | ||
4ed70ce9 | 18 | static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) |
cf85d08f LB |
19 | { |
20 | struct dsa_slave_priv *p = netdev_priv(dev); | |
21 | u8 *dsa_header; | |
22 | ||
cf85d08f LB |
23 | /* |
24 | * Convert the outermost 802.1q tag to a DSA tag for tagged | |
25 | * packets, or insert a DSA tag between the addresses and | |
26 | * the ethertype field for untagged packets. | |
27 | */ | |
28 | if (skb->protocol == htons(ETH_P_8021Q)) { | |
29 | if (skb_cow_head(skb, 0) < 0) | |
30 | goto out_free; | |
31 | ||
32 | /* | |
33 | * Construct tagged FROM_CPU DSA tag from 802.1q tag. | |
34 | */ | |
35 | dsa_header = skb->data + 2 * ETH_ALEN; | |
e84665c9 | 36 | dsa_header[0] = 0x60 | p->parent->index; |
cf85d08f LB |
37 | dsa_header[1] = p->port << 3; |
38 | ||
39 | /* | |
40 | * Move CFI field from byte 2 to byte 1. | |
41 | */ | |
42 | if (dsa_header[2] & 0x10) { | |
43 | dsa_header[1] |= 0x01; | |
44 | dsa_header[2] &= ~0x10; | |
45 | } | |
46 | } else { | |
47 | if (skb_cow_head(skb, DSA_HLEN) < 0) | |
48 | goto out_free; | |
49 | skb_push(skb, DSA_HLEN); | |
50 | ||
51 | memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); | |
52 | ||
53 | /* | |
54 | * Construct untagged FROM_CPU DSA tag. | |
55 | */ | |
56 | dsa_header = skb->data + 2 * ETH_ALEN; | |
e84665c9 | 57 | dsa_header[0] = 0x40 | p->parent->index; |
cf85d08f LB |
58 | dsa_header[1] = p->port << 3; |
59 | dsa_header[2] = 0x00; | |
60 | dsa_header[3] = 0x00; | |
61 | } | |
62 | ||
4ed70ce9 | 63 | return skb; |
cf85d08f LB |
64 | |
65 | out_free: | |
66 | kfree_skb(skb); | |
4ed70ce9 | 67 | return NULL; |
cf85d08f LB |
68 | } |
69 | ||
70 | static int dsa_rcv(struct sk_buff *skb, struct net_device *dev, | |
71 | struct packet_type *pt, struct net_device *orig_dev) | |
72 | { | |
e84665c9 LB |
73 | struct dsa_switch_tree *dst = dev->dsa_ptr; |
74 | struct dsa_switch *ds; | |
cf85d08f | 75 | u8 *dsa_header; |
e84665c9 | 76 | int source_device; |
cf85d08f LB |
77 | int source_port; |
78 | ||
e84665c9 | 79 | if (unlikely(dst == NULL)) |
cf85d08f LB |
80 | goto out_drop; |
81 | ||
82 | skb = skb_unshare(skb, GFP_ATOMIC); | |
83 | if (skb == NULL) | |
84 | goto out; | |
85 | ||
86 | if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) | |
87 | goto out_drop; | |
88 | ||
89 | /* | |
90 | * The ethertype field is part of the DSA header. | |
91 | */ | |
92 | dsa_header = skb->data - 2; | |
93 | ||
94 | /* | |
e84665c9 | 95 | * Check that frame type is either TO_CPU or FORWARD. |
cf85d08f | 96 | */ |
e84665c9 | 97 | if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) |
cf85d08f LB |
98 | goto out_drop; |
99 | ||
100 | /* | |
e84665c9 | 101 | * Determine source device and port. |
cf85d08f | 102 | */ |
e84665c9 | 103 | source_device = dsa_header[0] & 0x1f; |
cf85d08f | 104 | source_port = (dsa_header[1] >> 3) & 0x1f; |
e84665c9 LB |
105 | |
106 | /* | |
107 | * Check that the source device exists and that the source | |
108 | * port is a registered DSA port. | |
109 | */ | |
110 | if (source_device >= dst->pd->nr_chips) | |
111 | goto out_drop; | |
112 | ds = dst->ds[source_device]; | |
cf85d08f LB |
113 | if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) |
114 | goto out_drop; | |
115 | ||
116 | /* | |
117 | * Convert the DSA header to an 802.1q header if the 'tagged' | |
118 | * bit in the DSA header is set. If the 'tagged' bit is clear, | |
119 | * delete the DSA header entirely. | |
120 | */ | |
121 | if (dsa_header[0] & 0x20) { | |
122 | u8 new_header[4]; | |
123 | ||
124 | /* | |
125 | * Insert 802.1q ethertype and copy the VLAN-related | |
126 | * fields, but clear the bit that will hold CFI (since | |
127 | * DSA uses that bit location for another purpose). | |
128 | */ | |
129 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; | |
130 | new_header[1] = ETH_P_8021Q & 0xff; | |
131 | new_header[2] = dsa_header[2] & ~0x10; | |
132 | new_header[3] = dsa_header[3]; | |
133 | ||
134 | /* | |
135 | * Move CFI bit from its place in the DSA header to | |
136 | * its 802.1q-designated place. | |
137 | */ | |
138 | if (dsa_header[1] & 0x01) | |
139 | new_header[2] |= 0x10; | |
140 | ||
141 | /* | |
142 | * Update packet checksum if skb is CHECKSUM_COMPLETE. | |
143 | */ | |
144 | if (skb->ip_summed == CHECKSUM_COMPLETE) { | |
145 | __wsum c = skb->csum; | |
146 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); | |
147 | c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); | |
148 | skb->csum = c; | |
149 | } | |
150 | ||
151 | memcpy(dsa_header, new_header, DSA_HLEN); | |
152 | } else { | |
153 | /* | |
154 | * Remove DSA tag and update checksum. | |
155 | */ | |
156 | skb_pull_rcsum(skb, DSA_HLEN); | |
157 | memmove(skb->data - ETH_HLEN, | |
158 | skb->data - ETH_HLEN - DSA_HLEN, | |
159 | 2 * ETH_ALEN); | |
160 | } | |
161 | ||
162 | skb->dev = ds->ports[source_port]; | |
163 | skb_push(skb, ETH_HLEN); | |
14ee6742 | 164 | skb->pkt_type = PACKET_HOST; |
cf85d08f LB |
165 | skb->protocol = eth_type_trans(skb, skb->dev); |
166 | ||
cf85d08f LB |
167 | skb->dev->stats.rx_packets++; |
168 | skb->dev->stats.rx_bytes += skb->len; | |
169 | ||
170 | netif_receive_skb(skb); | |
171 | ||
172 | return 0; | |
173 | ||
174 | out_drop: | |
175 | kfree_skb(skb); | |
176 | out: | |
177 | return 0; | |
178 | } | |
179 | ||
3e8a72d1 FF |
180 | const struct dsa_device_ops dsa_netdev_ops = { |
181 | .xmit = dsa_xmit, | |
182 | .rcv = dsa_rcv, | |
cf85d08f | 183 | }; |