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net: dsa: tag_mtk: fix 802.1ad VLAN egress
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commit 9200f51 upstream.

A different TPID bit is used for 802.1ad VLAN frames.

Reported-by: Ilario Gelmetti <iochesonome@gmail.com>
Fixes: f0af343 ("net: dsa: mediatek: combine MediaTek tag with VLAN tag")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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LGA1150 authored and gregkh committed Mar 17, 2021
1 parent 8220486 commit 10ec8fe
Showing 1 changed file with 13 additions and 6 deletions.
19 changes: 13 additions & 6 deletions net/dsa/tag_mtk.c
Expand Up @@ -13,6 +13,7 @@
#define MTK_HDR_LEN 4
#define MTK_HDR_XMIT_UNTAGGED 0
#define MTK_HDR_XMIT_TAGGED_TPID_8100 1
#define MTK_HDR_XMIT_TAGGED_TPID_88A8 2
#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
#define MTK_HDR_XMIT_SA_DIS BIT(6)
Expand All @@ -21,8 +22,8 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
u8 xmit_tpid;
u8 *mtk_tag;
bool is_vlan_skb = true;
unsigned char *dest = eth_hdr(skb)->h_dest;
bool is_multicast_skb = is_multicast_ether_addr(dest) &&
!is_broadcast_ether_addr(dest);
Expand All @@ -33,27 +34,33 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
* the both special and VLAN tag at the same time and then look up VLAN
* table with VID.
*/
if (!skb_vlan_tagged(skb)) {
switch (skb->protocol) {
case htons(ETH_P_8021Q):
xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_8100;
break;
case htons(ETH_P_8021AD):
xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_88A8;
break;
default:
xmit_tpid = MTK_HDR_XMIT_UNTAGGED;
skb_push(skb, MTK_HDR_LEN);
memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
is_vlan_skb = false;
}

mtk_tag = skb->data + 2 * ETH_ALEN;

/* Mark tag attribute on special tag insertion to notify hardware
* whether that's a combined special tag with 802.1Q header.
*/
mtk_tag[0] = is_vlan_skb ? MTK_HDR_XMIT_TAGGED_TPID_8100 :
MTK_HDR_XMIT_UNTAGGED;
mtk_tag[0] = xmit_tpid;
mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;

/* Disable SA learning for multicast frames */
if (unlikely(is_multicast_skb))
mtk_tag[1] |= MTK_HDR_XMIT_SA_DIS;

/* Tag control information is kept for 802.1Q */
if (!is_vlan_skb) {
if (xmit_tpid == MTK_HDR_XMIT_UNTAGGED) {
mtk_tag[2] = 0;
mtk_tag[3] = 0;
}
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