From f0a5b1118fa46b2c94d1e8008bdfe56ad7053ee3 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 23 Nov 2021 11:37:47 +0100 Subject: [PATCH] mt76: mt7915: 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 --- mt7915/mac.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/mt7915/mac.c b/mt7915/mac.c index 0358ee71..6c14cb1c 100644 --- a/mt7915/mac.c +++ b/mt7915/mac.c @@ -749,10 +749,29 @@ mt7915_mac_fill_rx(struct mt7915_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); } }