fe47d56306
As of a86d8becc3 ("net: dsa: Factor bottom tag receive functions"),
the rcv caller frees the original SKB in case or error.
Be symmetric with that and make the xmit caller do the same.
At the same time, fix the checkpatch NULL comparison check:
CHECK: Comparison to NULL could be written "!nskb"
#208: FILE: net/dsa/tag_trailer.c:35:
+ if (nskb == NULL)
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
134 lines
3.8 KiB
C
134 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 "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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return NULL;
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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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}
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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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