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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> | |
13 | #include <linux/netdevice.h> | |
14 | #include "dsa_priv.h" | |
15 | ||
16 | #define DSA_HLEN 4 | |
17 | ||
6fef4c0c | 18 | netdev_tx_t 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 | ||
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; | |
e84665c9 | 39 | dsa_header[0] = 0x60 | p->parent->index; |
cf85d08f LB |
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; | |
e84665c9 | 60 | dsa_header[0] = 0x40 | p->parent->index; |
cf85d08f LB |
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 | ||
e84665c9 | 68 | skb->dev = p->parent->dst->master_netdev; |
cf85d08f LB |
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 | { | |
e84665c9 LB |
81 | struct dsa_switch_tree *dst = dev->dsa_ptr; |
82 | struct dsa_switch *ds; | |
cf85d08f | 83 | u8 *dsa_header; |
e84665c9 | 84 | int source_device; |
cf85d08f LB |
85 | int source_port; |
86 | ||
e84665c9 | 87 | if (unlikely(dst == NULL)) |
cf85d08f LB |
88 | goto out_drop; |
89 | ||
90 | skb = skb_unshare(skb, GFP_ATOMIC); | |
91 | if (skb == NULL) | |
92 | goto out; | |
93 | ||
94 | if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) | |
95 | goto out_drop; | |
96 | ||
97 | /* | |
98 | * The ethertype field is part of the DSA header. | |
99 | */ | |
100 | dsa_header = skb->data - 2; | |
101 | ||
102 | /* | |
e84665c9 | 103 | * Check that frame type is either TO_CPU or FORWARD. |
cf85d08f | 104 | */ |
e84665c9 | 105 | if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) |
cf85d08f LB |
106 | goto out_drop; |
107 | ||
108 | /* | |
e84665c9 | 109 | * Determine source device and port. |
cf85d08f | 110 | */ |
e84665c9 | 111 | source_device = dsa_header[0] & 0x1f; |
cf85d08f | 112 | source_port = (dsa_header[1] >> 3) & 0x1f; |
e84665c9 LB |
113 | |
114 | /* | |
115 | * Check that the source device exists and that the source | |
116 | * port is a registered DSA port. | |
117 | */ | |
118 | if (source_device >= dst->pd->nr_chips) | |
119 | goto out_drop; | |
120 | ds = dst->ds[source_device]; | |
cf85d08f LB |
121 | if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) |
122 | goto out_drop; | |
123 | ||
124 | /* | |
125 | * Convert the DSA header to an 802.1q header if the 'tagged' | |
126 | * bit in the DSA header is set. If the 'tagged' bit is clear, | |
127 | * delete the DSA header entirely. | |
128 | */ | |
129 | if (dsa_header[0] & 0x20) { | |
130 | u8 new_header[4]; | |
131 | ||
132 | /* | |
133 | * Insert 802.1q ethertype and copy the VLAN-related | |
134 | * fields, but clear the bit that will hold CFI (since | |
135 | * DSA uses that bit location for another purpose). | |
136 | */ | |
137 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; | |
138 | new_header[1] = ETH_P_8021Q & 0xff; | |
139 | new_header[2] = dsa_header[2] & ~0x10; | |
140 | new_header[3] = dsa_header[3]; | |
141 | ||
142 | /* | |
143 | * Move CFI bit from its place in the DSA header to | |
144 | * its 802.1q-designated place. | |
145 | */ | |
146 | if (dsa_header[1] & 0x01) | |
147 | new_header[2] |= 0x10; | |
148 | ||
149 | /* | |
150 | * Update packet checksum if skb is CHECKSUM_COMPLETE. | |
151 | */ | |
152 | if (skb->ip_summed == CHECKSUM_COMPLETE) { | |
153 | __wsum c = skb->csum; | |
154 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); | |
155 | c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); | |
156 | skb->csum = c; | |
157 | } | |
158 | ||
159 | memcpy(dsa_header, new_header, DSA_HLEN); | |
160 | } else { | |
161 | /* | |
162 | * Remove DSA tag and update checksum. | |
163 | */ | |
164 | skb_pull_rcsum(skb, DSA_HLEN); | |
165 | memmove(skb->data - ETH_HLEN, | |
166 | skb->data - ETH_HLEN - DSA_HLEN, | |
167 | 2 * ETH_ALEN); | |
168 | } | |
169 | ||
170 | skb->dev = ds->ports[source_port]; | |
171 | skb_push(skb, ETH_HLEN); | |
14ee6742 | 172 | skb->pkt_type = PACKET_HOST; |
cf85d08f LB |
173 | skb->protocol = eth_type_trans(skb, skb->dev); |
174 | ||
cf85d08f LB |
175 | skb->dev->stats.rx_packets++; |
176 | skb->dev->stats.rx_bytes += skb->len; | |
177 | ||
178 | netif_receive_skb(skb); | |
179 | ||
180 | return 0; | |
181 | ||
182 | out_drop: | |
183 | kfree_skb(skb); | |
184 | out: | |
185 | return 0; | |
186 | } | |
187 | ||
7546dd97 | 188 | static struct packet_type dsa_packet_type __read_mostly = { |
09640e63 | 189 | .type = cpu_to_be16(ETH_P_DSA), |
cf85d08f LB |
190 | .func = dsa_rcv, |
191 | }; | |
192 | ||
193 | static int __init dsa_init_module(void) | |
194 | { | |
195 | dev_add_pack(&dsa_packet_type); | |
196 | return 0; | |
197 | } | |
198 | module_init(dsa_init_module); | |
199 | ||
200 | static void __exit dsa_cleanup_module(void) | |
201 | { | |
202 | dev_remove_pack(&dsa_packet_type); | |
203 | } | |
204 | module_exit(dsa_cleanup_module); |