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91da11f8 LB |
1 | /* |
2 | * net/dsa/tag_edsa.c - Ethertype DSA tagging | |
e84665c9 | 3 | * Copyright (c) 2008-2009 Marvell Semiconductor |
91da11f8 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> |
91da11f8 LB |
14 | #include "dsa_priv.h" |
15 | ||
16 | #define DSA_HLEN 4 | |
17 | #define EDSA_HLEN 8 | |
18 | ||
4ed70ce9 | 19 | static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev) |
91da11f8 LB |
20 | { |
21 | struct dsa_slave_priv *p = netdev_priv(dev); | |
22 | u8 *edsa_header; | |
23 | ||
91da11f8 LB |
24 | /* |
25 | * Convert the outermost 802.1q tag to a DSA tag and prepend | |
26 | * a DSA ethertype field is the packet is tagged, or insert | |
27 | * a DSA ethertype plus DSA tag between the addresses and the | |
28 | * current ethertype field if the packet is untagged. | |
29 | */ | |
30 | if (skb->protocol == htons(ETH_P_8021Q)) { | |
31 | if (skb_cow_head(skb, DSA_HLEN) < 0) | |
32 | goto out_free; | |
33 | skb_push(skb, DSA_HLEN); | |
34 | ||
35 | memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); | |
36 | ||
37 | /* | |
38 | * Construct tagged FROM_CPU DSA tag from 802.1q tag. | |
39 | */ | |
40 | edsa_header = skb->data + 2 * ETH_ALEN; | |
41 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; | |
42 | edsa_header[1] = ETH_P_EDSA & 0xff; | |
43 | edsa_header[2] = 0x00; | |
44 | edsa_header[3] = 0x00; | |
e84665c9 | 45 | edsa_header[4] = 0x60 | p->parent->index; |
91da11f8 LB |
46 | edsa_header[5] = p->port << 3; |
47 | ||
48 | /* | |
49 | * Move CFI field from byte 6 to byte 5. | |
50 | */ | |
51 | if (edsa_header[6] & 0x10) { | |
52 | edsa_header[5] |= 0x01; | |
53 | edsa_header[6] &= ~0x10; | |
54 | } | |
55 | } else { | |
56 | if (skb_cow_head(skb, EDSA_HLEN) < 0) | |
57 | goto out_free; | |
58 | skb_push(skb, EDSA_HLEN); | |
59 | ||
60 | memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN); | |
61 | ||
62 | /* | |
63 | * Construct untagged FROM_CPU DSA tag. | |
64 | */ | |
65 | edsa_header = skb->data + 2 * ETH_ALEN; | |
66 | edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; | |
67 | edsa_header[1] = ETH_P_EDSA & 0xff; | |
68 | edsa_header[2] = 0x00; | |
69 | edsa_header[3] = 0x00; | |
e84665c9 | 70 | edsa_header[4] = 0x40 | p->parent->index; |
91da11f8 LB |
71 | edsa_header[5] = p->port << 3; |
72 | edsa_header[6] = 0x00; | |
73 | edsa_header[7] = 0x00; | |
74 | } | |
75 | ||
4ed70ce9 | 76 | return skb; |
91da11f8 LB |
77 | |
78 | out_free: | |
79 | kfree_skb(skb); | |
4ed70ce9 | 80 | return NULL; |
91da11f8 LB |
81 | } |
82 | ||
83 | static int edsa_rcv(struct sk_buff *skb, struct net_device *dev, | |
84 | struct packet_type *pt, struct net_device *orig_dev) | |
85 | { | |
e84665c9 LB |
86 | struct dsa_switch_tree *dst = dev->dsa_ptr; |
87 | struct dsa_switch *ds; | |
91da11f8 | 88 | u8 *edsa_header; |
e84665c9 | 89 | int source_device; |
91da11f8 LB |
90 | int source_port; |
91 | ||
e84665c9 | 92 | if (unlikely(dst == NULL)) |
91da11f8 LB |
93 | goto out_drop; |
94 | ||
95 | skb = skb_unshare(skb, GFP_ATOMIC); | |
96 | if (skb == NULL) | |
97 | goto out; | |
98 | ||
99 | if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) | |
100 | goto out_drop; | |
101 | ||
102 | /* | |
103 | * Skip the two null bytes after the ethertype. | |
104 | */ | |
105 | edsa_header = skb->data + 2; | |
106 | ||
107 | /* | |
e84665c9 | 108 | * Check that frame type is either TO_CPU or FORWARD. |
91da11f8 | 109 | */ |
e84665c9 | 110 | if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0) |
91da11f8 LB |
111 | goto out_drop; |
112 | ||
113 | /* | |
e84665c9 | 114 | * Determine source device and port. |
91da11f8 | 115 | */ |
e84665c9 | 116 | source_device = edsa_header[0] & 0x1f; |
91da11f8 | 117 | source_port = (edsa_header[1] >> 3) & 0x1f; |
e84665c9 LB |
118 | |
119 | /* | |
120 | * Check that the source device exists and that the source | |
121 | * port is a registered DSA port. | |
122 | */ | |
123 | if (source_device >= dst->pd->nr_chips) | |
124 | goto out_drop; | |
125 | ds = dst->ds[source_device]; | |
91da11f8 LB |
126 | if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) |
127 | goto out_drop; | |
128 | ||
129 | /* | |
130 | * If the 'tagged' bit is set, convert the DSA tag to a 802.1q | |
131 | * tag and delete the ethertype part. If the 'tagged' bit is | |
132 | * clear, delete the ethertype and the DSA tag parts. | |
133 | */ | |
134 | if (edsa_header[0] & 0x20) { | |
135 | u8 new_header[4]; | |
136 | ||
137 | /* | |
138 | * Insert 802.1q ethertype and copy the VLAN-related | |
139 | * fields, but clear the bit that will hold CFI (since | |
140 | * DSA uses that bit location for another purpose). | |
141 | */ | |
142 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; | |
143 | new_header[1] = ETH_P_8021Q & 0xff; | |
144 | new_header[2] = edsa_header[2] & ~0x10; | |
145 | new_header[3] = edsa_header[3]; | |
146 | ||
147 | /* | |
148 | * Move CFI bit from its place in the DSA header to | |
149 | * its 802.1q-designated place. | |
150 | */ | |
151 | if (edsa_header[1] & 0x01) | |
152 | new_header[2] |= 0x10; | |
153 | ||
154 | skb_pull_rcsum(skb, DSA_HLEN); | |
155 | ||
156 | /* | |
157 | * Update packet checksum if skb is CHECKSUM_COMPLETE. | |
158 | */ | |
159 | if (skb->ip_summed == CHECKSUM_COMPLETE) { | |
160 | __wsum c = skb->csum; | |
161 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); | |
162 | c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0)); | |
163 | skb->csum = c; | |
164 | } | |
165 | ||
166 | memcpy(edsa_header, new_header, DSA_HLEN); | |
167 | ||
168 | memmove(skb->data - ETH_HLEN, | |
169 | skb->data - ETH_HLEN - DSA_HLEN, | |
170 | 2 * ETH_ALEN); | |
171 | } else { | |
172 | /* | |
173 | * Remove DSA tag and update checksum. | |
174 | */ | |
175 | skb_pull_rcsum(skb, EDSA_HLEN); | |
176 | memmove(skb->data - ETH_HLEN, | |
177 | skb->data - ETH_HLEN - EDSA_HLEN, | |
178 | 2 * ETH_ALEN); | |
179 | } | |
180 | ||
181 | skb->dev = ds->ports[source_port]; | |
182 | skb_push(skb, ETH_HLEN); | |
14ee6742 | 183 | skb->pkt_type = PACKET_HOST; |
91da11f8 LB |
184 | skb->protocol = eth_type_trans(skb, skb->dev); |
185 | ||
91da11f8 LB |
186 | skb->dev->stats.rx_packets++; |
187 | skb->dev->stats.rx_bytes += skb->len; | |
188 | ||
189 | netif_receive_skb(skb); | |
190 | ||
191 | return 0; | |
192 | ||
193 | out_drop: | |
194 | kfree_skb(skb); | |
195 | out: | |
196 | return 0; | |
197 | } | |
198 | ||
3e8a72d1 FF |
199 | const struct dsa_device_ops edsa_netdev_ops = { |
200 | .xmit = edsa_xmit, | |
201 | .rcv = edsa_rcv, | |
91da11f8 | 202 | }; |