[PATCH 6.1 1/2] wifi: mt76: fix receiving LLC packets on mt7615/mt7915

[PATCH 6.1 1/2] wifi: mt76: fix receiving LLC packets on mt7615/mt7915

[Felix Fietkau]

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 <chad.monroe@smartrg.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/mt7615/mac.c | 8 ++++----
 drivers/net/wireless/mediatek/mt76/mt7915/mac.c | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index d6aae60c440d..cbc6859e38ac 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/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/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index 1070838e7e16..ec996a587142 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/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;
 		}
 
-- 
2.36.1

[PATCH 6.1 2/2] wifi: mt76: fix rx checksum offload on mt7615/mt7915/mt7921

[Felix Fietkau]

Checking the relevant rxd bits for the checksum information only indicates
if the checksum verification was performed by the hardware and doesn't show
actual checksum errors. Checksum errors are indicated in the info field of
the DMA descriptor. Fix packets erroneously marked as CHECKSUM_UNNECESSARY
by checking the extra bits as well.
Those bits are only passed to the driver for MMIO devices at the moment, so
limit checksum offload to those.

Fixes: 2122dfbfd0bd ("mt76: mt7615: add rx checksum offload support")
Fixes: 94244d2ea503 ("mt76: mt7915: add rx checksum offload support")
Fixes: 0e75732764e8 ("mt76: mt7921: enable rx csum offload")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/dma.c        | 5 +----
 drivers/net/wireless/mediatek/mt76/mt7615/mac.c | 4 +++-
 drivers/net/wireless/mediatek/mt76/mt7915/mac.c | 4 +++-
 drivers/net/wireless/mediatek/mt76/mt7921/mac.c | 4 +++-
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index ceb63b3aaced..c8ab7abcdbb5 100644
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -717,10 +717,7 @@ mt76_dma_rx_process(struct mt76_dev *dev, struct mt76_queue *q, int budget)
 
 		skb_reserve(skb, q->buf_offset);
 
-		if (q == &dev->q_rx[MT_RXQ_MCU]) {
-			u32 *rxfce = (u32 *)skb->cb;
-			*rxfce = info;
-		}
+		*(u32 *)skb->cb = info;
 
 		__skb_put(skb, len);
 		done++;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index cbc6859e38ac..2ce1705c0f43 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -345,6 +345,7 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
 	u32 rxd1 = le32_to_cpu(rxd[1]);
 	u32 rxd2 = le32_to_cpu(rxd[2]);
 	u32 csum_mask = MT_RXD0_NORMAL_IP_SUM | MT_RXD0_NORMAL_UDP_TCP_SUM;
+	u32 csum_status = *(u32 *)skb->cb;
 	bool unicast, hdr_trans, remove_pad, insert_ccmp_hdr = false;
 	u16 hdr_gap;
 	int phy_idx;
@@ -394,7 +395,8 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
 		spin_unlock_bh(&dev->sta_poll_lock);
 	}
 
-	if ((rxd0 & csum_mask) == csum_mask)
+	if (mt76_is_mmio(&dev->mt76) && (rxd0 & csum_mask) == csum_mask &&
+	    !(csum_status & (BIT(0) | BIT(2) | BIT(3))))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 	if (rxd2 & MT_RXD2_NORMAL_FCS_ERR)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index ec996a587142..324f0f58572b 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -233,6 +233,7 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
 	u8 remove_pad, amsdu_info;
 	u8 mode = 0, qos_ctl = 0;
 	struct mt7915_sta *msta = NULL;
+	u32 csum_status = *(u32 *)skb->cb;
 	bool hdr_trans;
 	u16 hdr_gap;
 	u16 seq_ctrl = 0;
@@ -288,7 +289,8 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
 	if (!sband->channels)
 		return -EINVAL;
 
-	if ((rxd0 & csum_mask) == csum_mask)
+	if ((rxd0 & csum_mask) == csum_mask &&
+	    !(csum_status & (BIT(0) | BIT(2) | BIT(3))))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 	if (rxd1 & MT_RXD1_NORMAL_FCS_ERR)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index 8de5e36a3780..6860468ed191 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -230,6 +230,7 @@ mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
 	struct mt76_phy *mphy = &dev->mt76.phy;
 	struct mt7921_phy *phy = &dev->phy;
 	struct ieee80211_supported_band *sband;
+	u32 csum_status = *(u32 *)skb->cb;
 	u32 rxd0 = le32_to_cpu(rxd[0]);
 	u32 rxd1 = le32_to_cpu(rxd[1]);
 	u32 rxd2 = le32_to_cpu(rxd[2]);
@@ -290,7 +291,8 @@ mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
 	if (!sband->channels)
 		return -EINVAL;
 
-	if ((rxd0 & csum_mask) == csum_mask)
+	if (mt76_is_mmio(&dev->mt76) && (rxd0 & csum_mask) == csum_mask &&
+	    !(csum_status & (BIT(0) | BIT(2) | BIT(3))))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 	if (rxd1 & MT_RXD1_NORMAL_FCS_ERR)
-- 
2.36.1

Re: [PATCH 6.1 1/2] wifi: mt76: fix receiving LLC packets on mt7615/mt7915

[Kalle Valo]

Felix Fietkau <nbd@nbd.name> wrote:

> 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 <chad.monroe@smartrg.com>
> Signed-off-by: Felix Fietkau <nbd@nbd.name>

2 patches applied to wireless.git, thanks.

47c44088ac08 wifi: mt76: fix receiving LLC packets on mt7615/mt7915
443dc85ad13e wifi: mt76: fix rx checksum offload on mt7615/mt7915/mt7921

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20221005130824.23371-1-nbd@nbd.name/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches