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