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![Florian Fainelli](/assets/img/avatar_default.png)
tag_lan9303.c does check for a NULL dst but that's already checked by dsa_switch_rcv() one layer above. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Acked-by: Juergen Borleis <jbe@pengutronix.de> Signed-off-by: David S. Miller <davem@davemloft.net>
136 lines
3.8 KiB
C
136 lines
3.8 KiB
C
/*
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* Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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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 <net/dsa.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_MAX_PORTS 3
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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_slave_priv *p = netdev_priv(dev);
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u16 *lan9303_tag;
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/* insert a special VLAN tag between the MAC addresses
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* and the current ethertype field.
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*/
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if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) {
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dev_dbg(&dev->dev,
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"Cannot make room for the special tag. Dropping packet\n");
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goto out_free;
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}
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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 = (u16 *)(skb->data + 2 * ETH_ALEN);
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lan9303_tag[0] = htons(ETH_P_8021Q);
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lan9303_tag[1] = htons(p->dp->index | BIT(4));
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return skb;
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out_free:
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kfree_skb(skb);
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return NULL;
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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, struct net_device *orig_dev)
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{
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u16 *lan9303_tag;
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struct dsa_switch_tree *dst = dev->dsa_ptr;
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struct dsa_switch *ds;
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unsigned int source_port;
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ds = dst->ds[0];
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if (unlikely(!ds)) {
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dev_warn_ratelimited(&dev->dev, "Dropping packet, due to missing DSA switch device\n");
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return NULL;
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}
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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 = (u16 *)(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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source_port = ntohs(lan9303_tag[1]) & 0x3;
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if (source_port >= LAN9303_MAX_PORTS) {
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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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if (!ds->ports[source_port].netdev) {
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dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid netdev or device\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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/* forward the packet to the dedicated interface */
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skb->dev = ds->ports[source_port].netdev;
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return skb;
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}
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const struct dsa_device_ops lan9303_netdev_ops = {
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.xmit = lan9303_xmit,
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.rcv = lan9303_rcv,
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};
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