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>
94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
/*
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* Mediatek DSA Tag support
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* Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
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* Sean Wang <sean.wang@mediatek.com>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only 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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#include <linux/etherdevice.h>
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#include "dsa_priv.h"
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#define MTK_HDR_LEN 4
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#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
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#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
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static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
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struct net_device *dev)
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{
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struct dsa_slave_priv *p = netdev_priv(dev);
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u8 *mtk_tag;
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if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
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return NULL;
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skb_push(skb, MTK_HDR_LEN);
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memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
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/* Build the tag after the MAC Source Address */
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mtk_tag = skb->data + 2 * ETH_ALEN;
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mtk_tag[0] = 0;
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mtk_tag[1] = (1 << p->dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
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mtk_tag[2] = 0;
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mtk_tag[3] = 0;
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return skb;
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}
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static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pt,
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struct net_device *orig_dev)
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{
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struct dsa_switch_tree *dst = dev->dsa_ptr;
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struct dsa_switch *ds;
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int port;
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__be16 *phdr, hdr;
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if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
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return NULL;
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/* The MTK header is added by the switch between src addr
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* and ethertype at this point, skb->data points to 2 bytes
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* after src addr so header should be 2 bytes right before.
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*/
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phdr = (__be16 *)(skb->data - 2);
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hdr = ntohs(*phdr);
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/* Remove MTK tag and recalculate checksum. */
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skb_pull_rcsum(skb, MTK_HDR_LEN);
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memmove(skb->data - ETH_HLEN,
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skb->data - ETH_HLEN - MTK_HDR_LEN,
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2 * ETH_ALEN);
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/* This protocol doesn't support cascading multiple
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* switches so it's safe to assume the switch is first
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* in the tree.
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*/
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ds = dst->ds[0];
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if (!ds)
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return NULL;
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/* Get source port information */
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port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
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if (!ds->ports[port].netdev)
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return NULL;
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skb->dev = ds->ports[port].netdev;
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return skb;
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}
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const struct dsa_device_ops mtk_netdev_ops = {
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.xmit = mtk_tag_xmit,
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.rcv = mtk_tag_rcv,
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};
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