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1 | /* |
2 | * net/dsa/tag_edsa.c - Ethertype DSA tagging | |
3 | * Copyright (c) 2008 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 "dsa_priv.h" | |
15 | ||
16 | #define DSA_HLEN 4 | |
17 | #define EDSA_HLEN 8 | |
18 | ||
19 | int edsa_xmit(struct sk_buff *skb, struct net_device *dev) | |
20 | { | |
21 | struct dsa_slave_priv *p = netdev_priv(dev); | |
22 | u8 *edsa_header; | |
23 | ||
24 | dev->stats.tx_packets++; | |
25 | dev->stats.tx_bytes += skb->len; | |
26 | ||
27 | /* | |
28 | * Convert the outermost 802.1q tag to a DSA tag and prepend | |
29 | * a DSA ethertype field is the packet is tagged, or insert | |
30 | * a DSA ethertype plus DSA tag between the addresses and the | |
31 | * current ethertype field if the packet is untagged. | |
32 | */ | |
33 | if (skb->protocol == htons(ETH_P_8021Q)) { | |
34 | if (skb_cow_head(skb, DSA_HLEN) < 0) | |
35 | goto out_free; | |
36 | skb_push(skb, DSA_HLEN); | |
37 | ||
38 | memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); | |
39 | ||
40 | /* | |
41 | * Construct tagged FROM_CPU DSA tag from 802.1q tag. | |
42 | */ | |
43 | edsa_header = skb->data + 2 * ETH_ALEN; | |
44 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; | |
45 | edsa_header[1] = ETH_P_EDSA & 0xff; | |
46 | edsa_header[2] = 0x00; | |
47 | edsa_header[3] = 0x00; | |
48 | edsa_header[4] = 0x60; | |
49 | edsa_header[5] = p->port << 3; | |
50 | ||
51 | /* | |
52 | * Move CFI field from byte 6 to byte 5. | |
53 | */ | |
54 | if (edsa_header[6] & 0x10) { | |
55 | edsa_header[5] |= 0x01; | |
56 | edsa_header[6] &= ~0x10; | |
57 | } | |
58 | } else { | |
59 | if (skb_cow_head(skb, EDSA_HLEN) < 0) | |
60 | goto out_free; | |
61 | skb_push(skb, EDSA_HLEN); | |
62 | ||
63 | memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN); | |
64 | ||
65 | /* | |
66 | * Construct untagged FROM_CPU DSA tag. | |
67 | */ | |
68 | edsa_header = skb->data + 2 * ETH_ALEN; | |
69 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; | |
70 | edsa_header[1] = ETH_P_EDSA & 0xff; | |
71 | edsa_header[2] = 0x00; | |
72 | edsa_header[3] = 0x00; | |
73 | edsa_header[4] = 0x40; | |
74 | edsa_header[5] = p->port << 3; | |
75 | edsa_header[6] = 0x00; | |
76 | edsa_header[7] = 0x00; | |
77 | } | |
78 | ||
79 | skb->protocol = htons(ETH_P_EDSA); | |
80 | ||
81 | skb->dev = p->parent->master_netdev; | |
82 | dev_queue_xmit(skb); | |
83 | ||
84 | return NETDEV_TX_OK; | |
85 | ||
86 | out_free: | |
87 | kfree_skb(skb); | |
88 | return NETDEV_TX_OK; | |
89 | } | |
90 | ||
91 | static int edsa_rcv(struct sk_buff *skb, struct net_device *dev, | |
92 | struct packet_type *pt, struct net_device *orig_dev) | |
93 | { | |
94 | struct dsa_switch *ds = dev->dsa_ptr; | |
95 | u8 *edsa_header; | |
96 | int source_port; | |
97 | ||
98 | if (unlikely(ds == NULL)) | |
99 | goto out_drop; | |
100 | ||
101 | skb = skb_unshare(skb, GFP_ATOMIC); | |
102 | if (skb == NULL) | |
103 | goto out; | |
104 | ||
105 | if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) | |
106 | goto out_drop; | |
107 | ||
108 | /* | |
109 | * Skip the two null bytes after the ethertype. | |
110 | */ | |
111 | edsa_header = skb->data + 2; | |
112 | ||
113 | /* | |
114 | * Check that frame type is either TO_CPU or FORWARD, and | |
115 | * that the source device is zero. | |
116 | */ | |
117 | if ((edsa_header[0] & 0xdf) != 0x00 && (edsa_header[0] & 0xdf) != 0xc0) | |
118 | goto out_drop; | |
119 | ||
120 | /* | |
121 | * Check that the source port is a registered DSA port. | |
122 | */ | |
123 | source_port = (edsa_header[1] >> 3) & 0x1f; | |
124 | if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) | |
125 | goto out_drop; | |
126 | ||
127 | /* | |
128 | * If the 'tagged' bit is set, convert the DSA tag to a 802.1q | |
129 | * tag and delete the ethertype part. If the 'tagged' bit is | |
130 | * clear, delete the ethertype and the DSA tag parts. | |
131 | */ | |
132 | if (edsa_header[0] & 0x20) { | |
133 | u8 new_header[4]; | |
134 | ||
135 | /* | |
136 | * Insert 802.1q ethertype and copy the VLAN-related | |
137 | * fields, but clear the bit that will hold CFI (since | |
138 | * DSA uses that bit location for another purpose). | |
139 | */ | |
140 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; | |
141 | new_header[1] = ETH_P_8021Q & 0xff; | |
142 | new_header[2] = edsa_header[2] & ~0x10; | |
143 | new_header[3] = edsa_header[3]; | |
144 | ||
145 | /* | |
146 | * Move CFI bit from its place in the DSA header to | |
147 | * its 802.1q-designated place. | |
148 | */ | |
149 | if (edsa_header[1] & 0x01) | |
150 | new_header[2] |= 0x10; | |
151 | ||
152 | skb_pull_rcsum(skb, DSA_HLEN); | |
153 | ||
154 | /* | |
155 | * Update packet checksum if skb is CHECKSUM_COMPLETE. | |
156 | */ | |
157 | if (skb->ip_summed == CHECKSUM_COMPLETE) { | |
158 | __wsum c = skb->csum; | |
159 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); | |
160 | c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0)); | |
161 | skb->csum = c; | |
162 | } | |
163 | ||
164 | memcpy(edsa_header, new_header, DSA_HLEN); | |
165 | ||
166 | memmove(skb->data - ETH_HLEN, | |
167 | skb->data - ETH_HLEN - DSA_HLEN, | |
168 | 2 * ETH_ALEN); | |
169 | } else { | |
170 | /* | |
171 | * Remove DSA tag and update checksum. | |
172 | */ | |
173 | skb_pull_rcsum(skb, EDSA_HLEN); | |
174 | memmove(skb->data - ETH_HLEN, | |
175 | skb->data - ETH_HLEN - EDSA_HLEN, | |
176 | 2 * ETH_ALEN); | |
177 | } | |
178 | ||
179 | skb->dev = ds->ports[source_port]; | |
180 | skb_push(skb, ETH_HLEN); | |
14ee6742 | 181 | skb->pkt_type = PACKET_HOST; |
91da11f8 LB |
182 | skb->protocol = eth_type_trans(skb, skb->dev); |
183 | ||
91da11f8 LB |
184 | skb->dev->stats.rx_packets++; |
185 | skb->dev->stats.rx_bytes += skb->len; | |
186 | ||
187 | netif_receive_skb(skb); | |
188 | ||
189 | return 0; | |
190 | ||
191 | out_drop: | |
192 | kfree_skb(skb); | |
193 | out: | |
194 | return 0; | |
195 | } | |
196 | ||
197 | static struct packet_type edsa_packet_type = { | |
09640e63 | 198 | .type = cpu_to_be16(ETH_P_EDSA), |
91da11f8 LB |
199 | .func = edsa_rcv, |
200 | }; | |
201 | ||
202 | static int __init edsa_init_module(void) | |
203 | { | |
204 | dev_add_pack(&edsa_packet_type); | |
205 | return 0; | |
206 | } | |
207 | module_init(edsa_init_module); | |
208 | ||
209 | static void __exit edsa_cleanup_module(void) | |
210 | { | |
211 | dev_remove_pack(&edsa_packet_type); | |
212 | } | |
213 | module_exit(edsa_cleanup_module); |