Andrew Lunn | dfedd3b | 2019-04-28 19:37:10 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 2 | /* |
| 3 | * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging |
Lennert Buytenhek | e84665c | 2009-03-20 09:52:09 +0000 | [diff] [blame] | 4 | * Copyright (c) 2008-2009 Marvell Semiconductor |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 5 | */ |
| 6 | |
| 7 | #include <linux/etherdevice.h> |
| 8 | #include <linux/list.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 9 | #include <linux/slab.h> |
Vivien Didelot | ea5dd34 | 2017-05-17 15:46:03 -0400 | [diff] [blame] | 10 | |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 11 | #include "dsa_priv.h" |
| 12 | |
| 13 | #define DSA_HLEN 4 |
| 14 | |
Florian Fainelli | 4ed70ce | 2015-07-31 11:42:56 -0700 | [diff] [blame] | 15 | static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 16 | { |
Vivien Didelot | d945097 | 2017-10-16 11:12:15 -0400 | [diff] [blame] | 17 | struct dsa_port *dp = dsa_slave_to_port(dev); |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 18 | u8 *dsa_header; |
| 19 | |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 20 | /* |
| 21 | * Convert the outermost 802.1q tag to a DSA tag for tagged |
| 22 | * packets, or insert a DSA tag between the addresses and |
| 23 | * the ethertype field for untagged packets. |
| 24 | */ |
| 25 | if (skb->protocol == htons(ETH_P_8021Q)) { |
| 26 | if (skb_cow_head(skb, 0) < 0) |
Vivien Didelot | fe47d56 | 2017-06-01 16:07:15 -0400 | [diff] [blame] | 27 | return NULL; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 28 | |
| 29 | /* |
| 30 | * Construct tagged FROM_CPU DSA tag from 802.1q tag. |
| 31 | */ |
| 32 | dsa_header = skb->data + 2 * ETH_ALEN; |
Vivien Didelot | d945097 | 2017-10-16 11:12:15 -0400 | [diff] [blame] | 33 | dsa_header[0] = 0x60 | dp->ds->index; |
| 34 | dsa_header[1] = dp->index << 3; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 35 | |
| 36 | /* |
| 37 | * Move CFI field from byte 2 to byte 1. |
| 38 | */ |
| 39 | if (dsa_header[2] & 0x10) { |
| 40 | dsa_header[1] |= 0x01; |
| 41 | dsa_header[2] &= ~0x10; |
| 42 | } |
| 43 | } else { |
| 44 | if (skb_cow_head(skb, DSA_HLEN) < 0) |
Vivien Didelot | fe47d56 | 2017-06-01 16:07:15 -0400 | [diff] [blame] | 45 | return NULL; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 46 | skb_push(skb, DSA_HLEN); |
| 47 | |
| 48 | memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); |
| 49 | |
| 50 | /* |
| 51 | * Construct untagged FROM_CPU DSA tag. |
| 52 | */ |
| 53 | dsa_header = skb->data + 2 * ETH_ALEN; |
Vivien Didelot | d945097 | 2017-10-16 11:12:15 -0400 | [diff] [blame] | 54 | dsa_header[0] = 0x40 | dp->ds->index; |
| 55 | dsa_header[1] = dp->index << 3; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 56 | dsa_header[2] = 0x00; |
| 57 | dsa_header[3] = 0x00; |
| 58 | } |
| 59 | |
Florian Fainelli | 4ed70ce | 2015-07-31 11:42:56 -0700 | [diff] [blame] | 60 | return skb; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 61 | } |
| 62 | |
Florian Fainelli | a86d8be | 2017-04-08 08:55:23 -0700 | [diff] [blame] | 63 | static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev, |
Florian Westphal | 89e4950 | 2017-08-17 16:47:00 +0200 | [diff] [blame] | 64 | struct packet_type *pt) |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 65 | { |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 66 | u8 *dsa_header; |
Lennert Buytenhek | e84665c | 2009-03-20 09:52:09 +0000 | [diff] [blame] | 67 | int source_device; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 68 | int source_port; |
| 69 | |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 70 | if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) |
Vivien Didelot | 5470979 | 2017-06-01 16:07:14 -0400 | [diff] [blame] | 71 | return NULL; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 72 | |
| 73 | /* |
| 74 | * The ethertype field is part of the DSA header. |
| 75 | */ |
| 76 | dsa_header = skb->data - 2; |
| 77 | |
| 78 | /* |
Lennert Buytenhek | e84665c | 2009-03-20 09:52:09 +0000 | [diff] [blame] | 79 | * Check that frame type is either TO_CPU or FORWARD. |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 80 | */ |
Lennert Buytenhek | e84665c | 2009-03-20 09:52:09 +0000 | [diff] [blame] | 81 | if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) |
Vivien Didelot | 5470979 | 2017-06-01 16:07:14 -0400 | [diff] [blame] | 82 | return NULL; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 83 | |
| 84 | /* |
Lennert Buytenhek | e84665c | 2009-03-20 09:52:09 +0000 | [diff] [blame] | 85 | * Determine source device and port. |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 86 | */ |
Lennert Buytenhek | e84665c | 2009-03-20 09:52:09 +0000 | [diff] [blame] | 87 | source_device = dsa_header[0] & 0x1f; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 88 | source_port = (dsa_header[1] >> 3) & 0x1f; |
Lennert Buytenhek | e84665c | 2009-03-20 09:52:09 +0000 | [diff] [blame] | 89 | |
Vivien Didelot | 2231c43 | 2017-10-16 11:12:17 -0400 | [diff] [blame] | 90 | skb->dev = dsa_master_find_slave(dev, source_device, source_port); |
Vivien Didelot | 3775b1b | 2017-09-29 17:19:15 -0400 | [diff] [blame] | 91 | if (!skb->dev) |
Vivien Didelot | 5470979 | 2017-06-01 16:07:14 -0400 | [diff] [blame] | 92 | return NULL; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 93 | |
| 94 | /* |
| 95 | * Convert the DSA header to an 802.1q header if the 'tagged' |
| 96 | * bit in the DSA header is set. If the 'tagged' bit is clear, |
| 97 | * delete the DSA header entirely. |
| 98 | */ |
| 99 | if (dsa_header[0] & 0x20) { |
| 100 | u8 new_header[4]; |
| 101 | |
| 102 | /* |
| 103 | * Insert 802.1q ethertype and copy the VLAN-related |
| 104 | * fields, but clear the bit that will hold CFI (since |
| 105 | * DSA uses that bit location for another purpose). |
| 106 | */ |
| 107 | new_header[0] = (ETH_P_8021Q >> 8) & 0xff; |
| 108 | new_header[1] = ETH_P_8021Q & 0xff; |
| 109 | new_header[2] = dsa_header[2] & ~0x10; |
| 110 | new_header[3] = dsa_header[3]; |
| 111 | |
| 112 | /* |
| 113 | * Move CFI bit from its place in the DSA header to |
| 114 | * its 802.1q-designated place. |
| 115 | */ |
| 116 | if (dsa_header[1] & 0x01) |
| 117 | new_header[2] |= 0x10; |
| 118 | |
| 119 | /* |
| 120 | * Update packet checksum if skb is CHECKSUM_COMPLETE. |
| 121 | */ |
| 122 | if (skb->ip_summed == CHECKSUM_COMPLETE) { |
| 123 | __wsum c = skb->csum; |
| 124 | c = csum_add(c, csum_partial(new_header + 2, 2, 0)); |
| 125 | c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); |
| 126 | skb->csum = c; |
| 127 | } |
| 128 | |
| 129 | memcpy(dsa_header, new_header, DSA_HLEN); |
| 130 | } else { |
| 131 | /* |
| 132 | * Remove DSA tag and update checksum. |
| 133 | */ |
| 134 | skb_pull_rcsum(skb, DSA_HLEN); |
| 135 | memmove(skb->data - ETH_HLEN, |
| 136 | skb->data - ETH_HLEN - DSA_HLEN, |
| 137 | 2 * ETH_ALEN); |
| 138 | } |
| 139 | |
Andrew Lunn | 13edbdb | 2017-11-09 22:29:52 +0100 | [diff] [blame] | 140 | skb->offload_fwd_mark = 1; |
| 141 | |
Florian Fainelli | a86d8be | 2017-04-08 08:55:23 -0700 | [diff] [blame] | 142 | return skb; |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 143 | } |
| 144 | |
Rundong Ge | 57fd967 | 2019-02-16 08:35:24 +0000 | [diff] [blame] | 145 | static int dsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto, |
| 146 | int *offset) |
| 147 | { |
| 148 | *offset = 4; |
| 149 | *proto = ((__be16 *)skb->data)[1]; |
| 150 | return 0; |
| 151 | } |
| 152 | |
Andrew Lunn | f81a43e | 2019-04-28 19:37:21 +0200 | [diff] [blame] | 153 | static const struct dsa_device_ops dsa_netdev_ops = { |
Andrew Lunn | 875138f | 2019-04-28 19:37:11 +0200 | [diff] [blame] | 154 | .name = "dsa", |
Andrew Lunn | 056eed2 | 2019-04-28 19:37:14 +0200 | [diff] [blame] | 155 | .proto = DSA_TAG_PROTO_DSA, |
Florian Fainelli | 3e8a72d | 2014-08-27 17:04:46 -0700 | [diff] [blame] | 156 | .xmit = dsa_xmit, |
| 157 | .rcv = dsa_rcv, |
Rundong Ge | 57fd967 | 2019-02-16 08:35:24 +0000 | [diff] [blame] | 158 | .flow_dissect = dsa_tag_flow_dissect, |
Andrew Lunn | a5dd308 | 2018-12-06 11:36:04 +0100 | [diff] [blame] | 159 | .overhead = DSA_HLEN, |
Lennert Buytenhek | cf85d08 | 2008-10-07 13:45:02 +0000 | [diff] [blame] | 160 | }; |
Andrew Lunn | 0b42f03 | 2019-04-28 19:37:12 +0200 | [diff] [blame] | 161 | |
Andrew Lunn | f18bba5 | 2019-04-28 19:37:13 +0200 | [diff] [blame] | 162 | MODULE_LICENSE("GPL"); |
Andrew Lunn | 0b42f03 | 2019-04-28 19:37:12 +0200 | [diff] [blame] | 163 | MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_DSA); |
Andrew Lunn | d3b8c04 | 2019-04-28 19:37:15 +0200 | [diff] [blame] | 164 | |
| 165 | module_dsa_tag_driver(dsa_netdev_ops); |