[PATCH 5.17 139/772] mt76: fix encap offload ethernet type check

Greg Kroah-Hartman
2022-06-07T20:39:20Z

From: Felix Fietkau <nbd@nbd.name>

[ Upstream commit bc98e7fdd80d215b4b55eea001023231eb8ce12e ]

The driver needs to check if the format is 802.2 vs 802.3 in order to set
a tx descriptor flag. skb->protocol can't be used, since it may not be properly
initialized for packets coming in from a packet socket.
Fix misdetection by checking the ethertype from the skb data instead

Reported-by: Thibaut VARÈNE <hacks+kernel@slashdirt.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/mediatek/mt76/mt7915/mac.c | 4 +++-
drivers/net/wireless/mediatek/mt76/mt7921/mac.c | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index e4c300aa1526..efc04f7a3c71 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -982,6 +982,7 @@ mt7915_mac_write_txwi_8023(struct mt7915_dev *dev, __le32 *txwi,

u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
u8 fc_type, fc_stype;
+ u16 ethertype;
bool wmm = false;
u32 val;

@@ -995,7 +996,8 @@ mt7915_mac_write_txwi_8023(struct mt7915_dev *dev, __le32 *txwi,
val = FIELD_PREP(MT_TXD1_HDR_FORMAT, MT_HDR_FORMAT_802_3) |
FIELD_PREP(MT_TXD1_TID, tid);

- if (be16_to_cpu(skb->protocol) >= ETH_P_802_3_MIN)
+ ethertype = get_unaligned_be16(&skb->data[12]);
+ if (ethertype >= ETH_P_802_3_MIN)
val |= MT_TXD1_ETH_802_3;

txwi[1] |= cpu_to_le32(val);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index e07707f518a2..eac2d85b5864 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -816,6 +816,7 @@ mt7921_mac_write_txwi_8023(struct mt7921_dev *dev, __le32 *txwi,
{
u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
u8 fc_type, fc_stype;
+ u16 ethertype;
bool wmm = false;
u32 val;

@@ -829,7 +830,8 @@ mt7921_mac_write_txwi_8023(struct mt7921_dev *dev, __le32 *txwi,
val = FIELD_PREP(MT_TXD1_HDR_FORMAT, MT_HDR_FORMAT_802_3) |
FIELD_PREP(MT_TXD1_TID, tid);

- if (be16_to_cpu(skb->protocol) >= ETH_P_802_3_MIN)
+ ethertype = get_unaligned_be16(&skb->data[12]);
+ if (ethertype >= ETH_P_802_3_MIN)
val |= MT_TXD1_ETH_802_3;

txwi[1] |= cpu_to_le32(val);
--
2.35.1