From 2182de50a37c74e62e5fe3403932012834d4468d Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Wed, 5 Oct 2022 11:18:37 +0200 Subject: [PATCH] wifi: mt76: fix receiving LLC packets on mt7615/mt7915 When 802.3 decap offload is enabled, the hardware indicates header translation failure, whenever either the LLC-SNAP header was not found, or a VLAN header with an unregcognized tag is present. In that case, the hardware inserts a 2-byte length fields after the MAC addresses. For VLAN packets, this tag needs to be removed. However, for 802.3 LLC packets, the length bytes should be preserved, since there is no separate ethertype field in the data. This fixes an issue where the length field was omitted for LLC frames, causing them to be malformed after hardware decap. Fixes: 1eeff0b4c1a6 ("mt76: mt7915: fix decap offload corner case with 4-addr VLAN frames") Reported-by: Chad Monroe Signed-off-by: Felix Fietkau --- mt7615/mac.c | 8 ++++---- mt7915/mac.c | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/mt7615/mac.c b/mt7615/mac.c index d6aae60c..cbc6859e 100644 --- a/mt7615/mac.c +++ b/mt7615/mac.c @@ -610,14 +610,14 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb) * When header translation failure is indicated, * the hardware will insert an extra 2-byte field * containing the data length after the protocol - * type field. + * type field. This happens either when the LLC-SNAP + * pattern did not match, or if a VLAN header was + * detected. */ 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) + else pad_start = 0; } diff --git a/mt7915/mac.c b/mt7915/mac.c index a76c82b0..e66951de 100644 --- a/mt7915/mac.c +++ b/mt7915/mac.c @@ -446,14 +446,14 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb) * When header translation failure is indicated, * the hardware will insert an extra 2-byte field * containing the data length after the protocol - * type field. + * type field. This happens either when the LLC-SNAP + * pattern did not match, or if a VLAN header was + * detected. */ 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) + else pad_start = 0; }