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1 | /* |
2 | * net/dsa/tag_edsa.c - Ethertype DSA tagging |
3 | * Copyright (c) 2008-2009 Marvell Semiconductor |
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> |
13 | #include <linux/netdevice.h> |
14 | #include <linux/slab.h> |
15 | #include "dsa_priv.h" |
16 | |
17 | #define DSA_HLEN 4 |
18 | #define EDSA_HLEN 8 |
19 | |
20 | netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev) |
21 | { |
22 | struct dsa_slave_priv *p = netdev_priv(dev); |
23 | u8 *edsa_header; |
24 | |
25 | dev->stats.tx_packets++; |
26 | dev->stats.tx_bytes += skb->len; |
27 | |
28 | /* |
29 | * Convert the outermost 802.1q tag to a DSA tag and prepend |
30 | * a DSA ethertype field is the packet is tagged, or insert |
31 | * a DSA ethertype plus DSA tag between the addresses and the |
32 | * current ethertype field if the packet is untagged. |
33 | */ |
34 | if (skb->protocol == htons(ETH_P_8021Q)) { |
35 | if (skb_cow_head(skb, DSA_HLEN) < 0) |
36 | goto out_free; |
37 | skb_push(skb, DSA_HLEN); |
38 | |
39 | memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); |
40 | |
41 | /* |
42 | * Construct tagged FROM_CPU DSA tag from 802.1q tag. |
43 | */ |
44 | edsa_header = skb->data + 2 * ETH_ALEN; |
45 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; |
46 | edsa_header[1] = ETH_P_EDSA & 0xff; |
47 | edsa_header[2] = 0x00; |
48 | edsa_header[3] = 0x00; |
49 | edsa_header[4] = 0x60 | p->parent->index; |
50 | edsa_header[5] = p->port << 3; |
51 | |
52 | /* |
53 | * Move CFI field from byte 6 to byte 5. |
54 | */ |
55 | if (edsa_header[6] & 0x10) { |
56 | edsa_header[5] |= 0x01; |
57 | edsa_header[6] &= ~0x10; |
58 | } |
59 | } else { |
60 | if (skb_cow_head(skb, EDSA_HLEN) < 0) |
61 | goto out_free; |
62 | skb_push(skb, EDSA_HLEN); |
63 | |
64 | memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN); |
65 | |
66 | /* |
67 | * Construct untagged FROM_CPU DSA tag. |
68 | */ |
69 | edsa_header = skb->data + 2 * ETH_ALEN; |
70 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; |
71 | edsa_header[1] = ETH_P_EDSA & 0xff; |
72 | edsa_header[2] = 0x00; |
73 | edsa_header[3] = 0x00; |
74 | edsa_header[4] = 0x40 | p->parent->index; |
75 | edsa_header[5] = p->port << 3; |
76 | edsa_header[6] = 0x00; |
77 | edsa_header[7] = 0x00; |
78 | } |
79 | |
80 | skb->protocol = htons(ETH_P_EDSA); |
81 | |
82 | skb->dev = p->parent->dst->master_netdev; |
83 | dev_queue_xmit(skb); |
84 | |
85 | return NETDEV_TX_OK; |
86 | |
87 | out_free: |
88 | kfree_skb(skb); |
89 | return NETDEV_TX_OK; |
90 | } |
91 | |
92 | static int edsa_rcv(struct sk_buff *skb, struct net_device *dev, |
93 | struct packet_type *pt, struct net_device *orig_dev) |
94 | { |
95 | struct dsa_switch_tree *dst = dev->dsa_ptr; |
96 | struct dsa_switch *ds; |
97 | u8 *edsa_header; |
98 | int source_device; |
99 | int source_port; |
100 | |
101 | if (unlikely(dst == NULL)) |
102 | goto out_drop; |
103 | |
104 | skb = skb_unshare(skb, GFP_ATOMIC); |
105 | if (skb == NULL) |
106 | goto out; |
107 | |
108 | if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) |
109 | goto out_drop; |
110 | |
111 | /* |
112 | * Skip the two null bytes after the ethertype. |
113 | */ |
114 | edsa_header = skb->data + 2; |
115 | |
116 | /* |
117 | * Check that frame type is either TO_CPU or FORWARD. |
118 | */ |
119 | if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0) |
120 | goto out_drop; |
121 | |
122 | /* |
123 | * Determine source device and port. |
124 | */ |
125 | source_device = edsa_header[0] & 0x1f; |
126 | source_port = (edsa_header[1] >> 3) & 0x1f; |
127 | |
128 | /* |
129 | * Check that the source device exists and that the source |
130 | * port is a registered DSA port. |
131 | */ |
132 | if (source_device >= dst->pd->nr_chips) |
133 | goto out_drop; |
134 | ds = dst->ds[source_device]; |
135 | if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) |
136 | goto out_drop; |
137 | |
138 | /* |
139 | * If the 'tagged' bit is set, convert the DSA tag to a 802.1q |
140 | * tag and delete the ethertype part. If the 'tagged' bit is |
141 | * clear, delete the ethertype and the DSA tag parts. |
142 | */ |
143 | if (edsa_header[0] & 0x20) { |
144 | u8 new_header[4]; |
145 | |
146 | /* |
147 | * Insert 802.1q ethertype and copy the VLAN-related |
148 | * fields, but clear the bit that will hold CFI (since |
149 | * DSA uses that bit location for another purpose). |
150 | */ |
151 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; |
152 | new_header[1] = ETH_P_8021Q & 0xff; |
153 | new_header[2] = edsa_header[2] & ~0x10; |
154 | new_header[3] = edsa_header[3]; |
155 | |
156 | /* |
157 | * Move CFI bit from its place in the DSA header to |
158 | * its 802.1q-designated place. |
159 | */ |
160 | if (edsa_header[1] & 0x01) |
161 | new_header[2] |= 0x10; |
162 | |
163 | skb_pull_rcsum(skb, DSA_HLEN); |
164 | |
165 | /* |
166 | * Update packet checksum if skb is CHECKSUM_COMPLETE. |
167 | */ |
168 | if (skb->ip_summed == CHECKSUM_COMPLETE) { |
169 | __wsum c = skb->csum; |
170 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); |
171 | c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0)); |
172 | skb->csum = c; |
173 | } |
174 | |
175 | memcpy(edsa_header, new_header, DSA_HLEN); |
176 | |
177 | memmove(skb->data - ETH_HLEN, |
178 | skb->data - ETH_HLEN - DSA_HLEN, |
179 | 2 * ETH_ALEN); |
180 | } else { |
181 | /* |
182 | * Remove DSA tag and update checksum. |
183 | */ |
184 | skb_pull_rcsum(skb, EDSA_HLEN); |
185 | memmove(skb->data - ETH_HLEN, |
186 | skb->data - ETH_HLEN - EDSA_HLEN, |
187 | 2 * ETH_ALEN); |
188 | } |
189 | |
190 | skb->dev = ds->ports[source_port]; |
191 | skb_push(skb, ETH_HLEN); |
192 | skb->pkt_type = PACKET_HOST; |
193 | skb->protocol = eth_type_trans(skb, skb->dev); |
194 | |
195 | skb->dev->stats.rx_packets++; |
196 | skb->dev->stats.rx_bytes += skb->len; |
197 | |
198 | netif_receive_skb(skb); |
199 | |
200 | return 0; |
201 | |
202 | out_drop: |
203 | kfree_skb(skb); |
204 | out: |
205 | return 0; |
206 | } |
207 | |
208 | static struct packet_type edsa_packet_type __read_mostly = { |
209 | .type = cpu_to_be16(ETH_P_EDSA), |
210 | .func = edsa_rcv, |
211 | }; |
212 | |
213 | static int __init edsa_init_module(void) |
214 | { |
215 | dev_add_pack(&edsa_packet_type); |
216 | return 0; |
217 | } |
218 | module_init(edsa_init_module); |
219 | |
220 | static void __exit edsa_cleanup_module(void) |
221 | { |
222 | dev_remove_pack(&edsa_packet_type); |
223 | } |
224 | module_exit(edsa_cleanup_module); |
225 |
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