[PATCH] wifi: ath12k: correctly handle mcast packets for clients

[Oliver Sedlbauer <os@dev.tdt.de>]

From: Sarika Sharma <quic_sarishar@quicinc.com>

[ Upstream commit 4541b0c8c3c1b85564971d497224e57cf8076a02 ]

Currently, RX is_mcbc bit is set for packets sent from client as
destination address (DA) is multicast/broadcast address, but packets
are actually unicast as receiver address (RA) is not multicast address.
Hence, packets are not handled properly due to this is_mcbc bit.

Therefore, reset the is_mcbc bit if interface type is AP.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1

Signed-off-by: Sarika Sharma <quic_sarishar@quicinc.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20250411061523.859387-3-quic_sarishar@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
[ Adjust context ]
Signed-off-by: Oliver Sedlbauer <os@dev.tdt.de>
---
Context:
The issue was introduced in 6.12.y by the backport of commit f66971c608c4
("wifi: ath12k: using msdu end descriptor to check for rx multicast packets"),
which was part of a patchset:
https://lore.kernel.org/all/20250411061523.859387-1-quic_sarishar@quicinc.com/

That commit, without this follow-up patch, causes mac80211 to drop encrypted
ARP request frames.
As a result, ARP resolution fails, and connectivity from a station to an AP does
not work reliably until traffic is initiated by the AP.

This follow-up commit is necessary to restore correct network functionality for
ath12k clients on 6.12.y.

Note:
The patch has been modified to apply cleanly, including adjustments for
API changes.
The copyright header change has been omitted.


 drivers/net/wireless/ath/ath12k/dp_rx.c | 5 +++++
 drivers/net/wireless/ath/ath12k/peer.c  | 3 +++
 drivers/net/wireless/ath/ath12k/peer.h  | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/drivers/net/wireless/ath/ath12k/dp_rx.c b/drivers/net/wireless/ath/ath12k/dp_rx.c
index eebdcc16e8fc..1c0d796ffc7a 100644
--- a/drivers/net/wireless/ath/ath12k/dp_rx.c
+++ b/drivers/net/wireless/ath/ath12k/dp_rx.c
@@ -2214,6 +2214,11 @@ static void ath12k_dp_rx_h_mpdu(struct ath12k *ar,
 	spin_lock_bh(&ar->ab->base_lock);
 	peer = ath12k_dp_rx_h_find_peer(ar->ab, msdu);
 	if (peer) {
+		/* resetting mcbc bit because mcbc packets are unicast
+		 * packets only for AP as STA sends unicast packets.
+		 */
+		rxcb->is_mcbc = rxcb->is_mcbc && !peer->ucast_ra_only;
+
 		if (rxcb->is_mcbc)
 			enctype = peer->sec_type_grp;
 		else
diff --git a/drivers/net/wireless/ath/ath12k/peer.c b/drivers/net/wireless/ath/ath12k/peer.c
index 19c0626fbff1..461749b0f732 100644
--- a/drivers/net/wireless/ath/ath12k/peer.c
+++ b/drivers/net/wireless/ath/ath12k/peer.c
@@ -331,6 +331,9 @@ int ath12k_peer_create(struct ath12k *ar, struct ath12k_vif *arvif,
 		arvif->ast_idx = peer->hw_peer_id;
 	}

+	if (arvif->vif->type == NL80211_IFTYPE_AP)
+		peer->ucast_ra_only = true;
+
 	peer->sec_type = HAL_ENCRYPT_TYPE_OPEN;
 	peer->sec_type_grp = HAL_ENCRYPT_TYPE_OPEN;

diff --git a/drivers/net/wireless/ath/ath12k/peer.h b/drivers/net/wireless/ath/ath12k/peer.h
index 7b3500b5c8c2..05d4fdd3f82d 100644
--- a/drivers/net/wireless/ath/ath12k/peer.h
+++ b/drivers/net/wireless/ath/ath12k/peer.h
@@ -47,6 +47,8 @@ struct ath12k_peer {

 	/* protected by ab->data_lock */
 	bool dp_setup_done;
+
+	bool ucast_ra_only;
 };

 void ath12k_peer_unmap_event(struct ath12k_base *ab, u16 peer_id);
--
2.39.5