From 838fcae7f51ced6d011f7f0e4d705f8072426a16 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 23 Nov 2021 11:49:04 +0100 Subject: [PATCH] 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 --- .../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 e2b99b6163e1d..ec25e5a95d442 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); } } -- 2.30.2