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Lennert Buytenhek91da11f2008-10-07 13:44:02 +00001/*
2 * net/dsa/tag_edsa.c - Ethertype DSA tagging
Lennert Buytenheke84665c2009-03-20 09:52:09 +00003 * Copyright (c) 2008-2009 Marvell Semiconductor
Lennert Buytenhek91da11f2008-10-07 13:44:02 +00004 *
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090013#include <linux/slab.h>
Vivien Didelotea5dd342017-05-17 15:46:03 -040014
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000015#include "dsa_priv.h"
16
17#define DSA_HLEN 4
18#define EDSA_HLEN 8
19
Florian Fainelli4ed70ce2015-07-31 11:42:56 -070020static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000021{
Vivien Didelotd9450972017-10-16 11:12:15 -040022 struct dsa_port *dp = dsa_slave_to_port(dev);
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000023 u8 *edsa_header;
24
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000025 /*
26 * Convert the outermost 802.1q tag to a DSA tag and prepend
27 * a DSA ethertype field is the packet is tagged, or insert
28 * a DSA ethertype plus DSA tag between the addresses and the
29 * current ethertype field if the packet is untagged.
30 */
31 if (skb->protocol == htons(ETH_P_8021Q)) {
32 if (skb_cow_head(skb, DSA_HLEN) < 0)
Vivien Didelotfe47d562017-06-01 16:07:15 -040033 return NULL;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000034 skb_push(skb, DSA_HLEN);
35
36 memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
37
38 /*
39 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
40 */
41 edsa_header = skb->data + 2 * ETH_ALEN;
42 edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
43 edsa_header[1] = ETH_P_EDSA & 0xff;
44 edsa_header[2] = 0x00;
45 edsa_header[3] = 0x00;
Vivien Didelotd9450972017-10-16 11:12:15 -040046 edsa_header[4] = 0x60 | dp->ds->index;
47 edsa_header[5] = dp->index << 3;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000048
49 /*
50 * Move CFI field from byte 6 to byte 5.
51 */
52 if (edsa_header[6] & 0x10) {
53 edsa_header[5] |= 0x01;
54 edsa_header[6] &= ~0x10;
55 }
56 } else {
57 if (skb_cow_head(skb, EDSA_HLEN) < 0)
Vivien Didelotfe47d562017-06-01 16:07:15 -040058 return NULL;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000059 skb_push(skb, EDSA_HLEN);
60
61 memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN);
62
63 /*
64 * Construct untagged FROM_CPU DSA tag.
65 */
66 edsa_header = skb->data + 2 * ETH_ALEN;
67 edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
68 edsa_header[1] = ETH_P_EDSA & 0xff;
69 edsa_header[2] = 0x00;
70 edsa_header[3] = 0x00;
Vivien Didelotd9450972017-10-16 11:12:15 -040071 edsa_header[4] = 0x40 | dp->ds->index;
72 edsa_header[5] = dp->index << 3;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000073 edsa_header[6] = 0x00;
74 edsa_header[7] = 0x00;
75 }
76
Florian Fainelli4ed70ce2015-07-31 11:42:56 -070077 return skb;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000078}
79
Florian Fainellia86d8be2017-04-08 08:55:23 -070080static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev,
Florian Westphal89e49502017-08-17 16:47:00 +020081 struct packet_type *pt)
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000082{
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000083 u8 *edsa_header;
Lennert Buytenheke84665c2009-03-20 09:52:09 +000084 int source_device;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000085 int source_port;
86
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000087 if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
Vivien Didelot54709792017-06-01 16:07:14 -040088 return NULL;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000089
90 /*
91 * Skip the two null bytes after the ethertype.
92 */
93 edsa_header = skb->data + 2;
94
95 /*
Lennert Buytenheke84665c2009-03-20 09:52:09 +000096 * Check that frame type is either TO_CPU or FORWARD.
Lennert Buytenhek91da11f2008-10-07 13:44:02 +000097 */
Lennert Buytenheke84665c2009-03-20 09:52:09 +000098 if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0)
Vivien Didelot54709792017-06-01 16:07:14 -040099 return NULL;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +0000100
101 /*
Lennert Buytenheke84665c2009-03-20 09:52:09 +0000102 * Determine source device and port.
Lennert Buytenhek91da11f2008-10-07 13:44:02 +0000103 */
Lennert Buytenheke84665c2009-03-20 09:52:09 +0000104 source_device = edsa_header[0] & 0x1f;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +0000105 source_port = (edsa_header[1] >> 3) & 0x1f;
Lennert Buytenheke84665c2009-03-20 09:52:09 +0000106
Vivien Didelot2231c432017-10-16 11:12:17 -0400107 skb->dev = dsa_master_find_slave(dev, source_device, source_port);
Vivien Didelot3775b1b2017-09-29 17:19:15 -0400108 if (!skb->dev)
Vivien Didelot54709792017-06-01 16:07:14 -0400109 return NULL;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +0000110
111 /*
112 * If the 'tagged' bit is set, convert the DSA tag to a 802.1q
113 * tag and delete the ethertype part. If the 'tagged' bit is
114 * clear, delete the ethertype and the DSA tag parts.
115 */
116 if (edsa_header[0] & 0x20) {
117 u8 new_header[4];
118
119 /*
120 * Insert 802.1q ethertype and copy the VLAN-related
121 * fields, but clear the bit that will hold CFI (since
122 * DSA uses that bit location for another purpose).
123 */
124 new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
125 new_header[1] = ETH_P_8021Q & 0xff;
126 new_header[2] = edsa_header[2] & ~0x10;
127 new_header[3] = edsa_header[3];
128
129 /*
130 * Move CFI bit from its place in the DSA header to
131 * its 802.1q-designated place.
132 */
133 if (edsa_header[1] & 0x01)
134 new_header[2] |= 0x10;
135
136 skb_pull_rcsum(skb, DSA_HLEN);
137
138 /*
139 * Update packet checksum if skb is CHECKSUM_COMPLETE.
140 */
141 if (skb->ip_summed == CHECKSUM_COMPLETE) {
142 __wsum c = skb->csum;
143 c = csum_add(c, csum_partial(new_header + 2, 2, 0));
144 c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0));
145 skb->csum = c;
146 }
147
148 memcpy(edsa_header, new_header, DSA_HLEN);
149
150 memmove(skb->data - ETH_HLEN,
151 skb->data - ETH_HLEN - DSA_HLEN,
152 2 * ETH_ALEN);
153 } else {
154 /*
155 * Remove DSA tag and update checksum.
156 */
157 skb_pull_rcsum(skb, EDSA_HLEN);
158 memmove(skb->data - ETH_HLEN,
159 skb->data - ETH_HLEN - EDSA_HLEN,
160 2 * ETH_ALEN);
161 }
162
Andrew Lunn13edbdb2017-11-09 22:29:52 +0100163 skb->offload_fwd_mark = 1;
164
Florian Fainellia86d8be2017-04-08 08:55:23 -0700165 return skb;
Lennert Buytenhek91da11f2008-10-07 13:44:02 +0000166}
167
Rundong Ge57fd9672019-02-16 08:35:24 +0000168static int edsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
169 int *offset)
170{
171 *offset = 8;
172 *proto = ((__be16 *)skb->data)[3];
173 return 0;
174}
175
Florian Fainelli3e8a72d2014-08-27 17:04:46 -0700176const struct dsa_device_ops edsa_netdev_ops = {
177 .xmit = edsa_xmit,
178 .rcv = edsa_rcv,
Rundong Ge57fd9672019-02-16 08:35:24 +0000179 .flow_dissect = edsa_tag_flow_dissect,
Andrew Lunna5dd3082018-12-06 11:36:04 +0100180 .overhead = EDSA_HLEN,
Lennert Buytenhek91da11f2008-10-07 13:44:02 +0000181};