2021-11-23 11:22:15

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH 2/2] mt76: mt7615: fix decap offload corner case with 4-addr VLAN frames

With 4-address mode VLAN frames, an internal header translation step fails,
leaving behind an extra 2-byte length field that must be reomved by the driver.
Add a check for this condition to fix receiving such packets

Signed-off-by: Felix Fietkau <[email protected]>
---
.../net/wireless/mediatek/mt76/mt7615/mac.c | 23 +++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index e2b99b6163e1..ec25e5a95d44 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -600,10 +600,29 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
return -EINVAL;
hdr_trans = false;
} else {
+ int pad_start = 0;
+
skb_pull(skb, hdr_gap);
if (!hdr_trans && status->amsdu) {
- memmove(skb->data + 2, skb->data,
- ieee80211_get_hdrlen_from_skb(skb));
+ pad_start = ieee80211_get_hdrlen_from_skb(skb);
+ } else if (hdr_trans && (rxd2 & MT_RXD2_NORMAL_HDR_TRANS_ERROR)) {
+ /*
+ * When header translation failure is indicated,
+ * the hardware will insert an extra 2-byte field
+ * containing the data length after the protocol
+ * type field.
+ */
+ pad_start = 12;
+ if (get_unaligned_be16(skb->data + pad_start) == ETH_P_8021Q)
+ pad_start += 4;
+
+ if (get_unaligned_be16(skb->data + pad_start) !=
+ skb->len - pad_start - 2)
+ pad_start = 0;
+ }
+
+ if (pad_start) {
+ memmove(skb->data + 2, skb->data, pad_start);
skb_pull(skb, 2);
}
}
--
2.30.1