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4e50025129
Some really really weird switches just couldn't decide whether to use a normal or a tail tagger, so they just did both. This creates problems for DSA, because we only have the concept of an 'overhead' which can be applied to the headroom or to the tailroom of the skb (like for example during the central TX reallocation procedure), depending on the value of bool tail_tag, but not to both. We need to generalize DSA to cater for these odd switches by transforming the 'overhead / tail_tag' pair into 'needed_headroom / needed_tailroom'. The DSA master's MTU is increased to account for both. The flow dissector code is modified such that it only calls the DSA adjustment callback if the tagger has a non-zero header length. Taggers are trivially modified to declare either needed_headroom or needed_tailroom, based on the tail_tag value that they currently declare. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
134 lines
4 KiB
C
134 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
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*/
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#include <linux/dsa/lan9303.h>
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#include <linux/etherdevice.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include "dsa_priv.h"
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/* To define the outgoing port and to discover the incoming port a regular
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* VLAN tag is used by the LAN9303. But its VID meaning is 'special':
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*
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* Dest MAC Src MAC TAG Type
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* ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |...
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* |<------->|
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* TAG:
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* |<------------->|
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* | 1 2 | 3 4 |
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* TPID VID
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* 0x8100
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*
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* VID bit 3 indicates a request for an ALR lookup.
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*
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* If VID bit 3 is zero, then bits 0 and 1 specify the destination port
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* (0, 1, 2) or broadcast (3) or the source port (1, 2).
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*
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* VID bit 4 is used to specify if the STP port state should be overridden.
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* Required when no forwarding between the external ports should happen.
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*/
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#define LAN9303_TAG_LEN 4
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# define LAN9303_TAG_TX_USE_ALR BIT(3)
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# define LAN9303_TAG_TX_STP_OVERRIDE BIT(4)
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# define LAN9303_TAG_RX_IGMP BIT(3)
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# define LAN9303_TAG_RX_STP BIT(4)
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# define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP | \
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LAN9303_TAG_RX_STP)
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/* Decide whether to transmit using ALR lookup, or transmit directly to
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* port using tag. ALR learning is performed only when using ALR lookup.
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* If the two external ports are bridged and the frame is unicast,
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* then use ALR lookup to allow ALR learning on CPU port.
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* Otherwise transmit directly to port with STP state override.
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* See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1
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*/
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static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr)
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{
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struct lan9303 *chip = dp->ds->priv;
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return chip->is_bridged && !is_multicast_ether_addr(dest_addr);
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}
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static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct dsa_port *dp = dsa_slave_to_port(dev);
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__be16 *lan9303_tag;
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u16 tag;
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/* provide 'LAN9303_TAG_LEN' bytes additional space */
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skb_push(skb, LAN9303_TAG_LEN);
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/* make room between MACs and Ether-Type */
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memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);
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lan9303_tag = (__be16 *)(skb->data + 2 * ETH_ALEN);
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tag = lan9303_xmit_use_arl(dp, skb->data) ?
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LAN9303_TAG_TX_USE_ALR :
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dp->index | LAN9303_TAG_TX_STP_OVERRIDE;
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lan9303_tag[0] = htons(ETH_P_8021Q);
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lan9303_tag[1] = htons(tag);
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return skb;
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}
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static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pt)
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{
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__be16 *lan9303_tag;
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u16 lan9303_tag1;
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unsigned int source_port;
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if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) {
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dev_warn_ratelimited(&dev->dev,
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"Dropping packet, cannot pull\n");
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return NULL;
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}
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/* '->data' points into the middle of our special VLAN tag information:
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*
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* ~ MAC src | 0x81 | 0x00 | 0xyy | 0xzz | ether type
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* ^
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* ->data
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*/
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lan9303_tag = (__be16 *)(skb->data - 2);
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if (lan9303_tag[0] != htons(ETH_P_8021Q)) {
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dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
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return NULL;
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}
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lan9303_tag1 = ntohs(lan9303_tag[1]);
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source_port = lan9303_tag1 & 0x3;
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skb->dev = dsa_master_find_slave(dev, 0, source_port);
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if (!skb->dev) {
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dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n");
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return NULL;
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}
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/* remove the special VLAN tag between the MAC addresses
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* and the current ethertype field.
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*/
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skb_pull_rcsum(skb, 2 + 2);
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memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),
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2 * ETH_ALEN);
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skb->offload_fwd_mark = !(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU);
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return skb;
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}
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static const struct dsa_device_ops lan9303_netdev_ops = {
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.name = "lan9303",
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.proto = DSA_TAG_PROTO_LAN9303,
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.xmit = lan9303_xmit,
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.rcv = lan9303_rcv,
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.needed_headroom = LAN9303_TAG_LEN,
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};
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN9303);
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module_dsa_tag_driver(lan9303_netdev_ops);
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