[PATCH rtw-next 08/13] wifi: rtw89: wow: send ARP reply packets instead of Null packets to keep alive

[Ping-Ke Shih <pkshih@realtek.com>]

From: Chin-Yen Lee <timlee@realtek.com>

In WoWLAN mode, the firmware periodically sends Null packets to the AP
to keep the connection alive and prevent the AP from disconnecting the
client due to inactivity. However, it was observed that certain APs,
such as  TP-Link Archer BE800, do not recognize Null packets as
valid activity and still drop the connection. Replacing Null packets
with ARP reply packets effectively resolves this compatibility issue
and maintains the connection.

Specifically, while the firmware typically handles standard ARP
offloads by dynamically modifying target IP/MAC fields, these
keep-alive ARP reply packets are pre-filled by the driver with the
DUT's own MAC and IP addresses for both sender and target fields.
In this case, the firmware transmits the packets as-is without
further modification. This approach ensures compatibility with APs
that require valid Layer 3 traffic for activity monitoring while
simplifying the firmware's processing logic during WoWLAN mode.

Signed-off-by: Chin-Yen Lee <timlee@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtw89/fw.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw89/fw.c b/drivers/net/wireless/realtek/rtw89/fw.c
index 29d8d13d11fe..eb5683d64461 100644
--- a/drivers/net/wireless/realtek/rtw89/fw.c
+++ b/drivers/net/wireless/realtek/rtw89/fw.c
@@ -2958,6 +2958,8 @@ static struct sk_buff *rtw89_arp_response_get(struct rtw89_dev *rtwdev,
 
 	ether_addr_copy(arp_skb->sender_hw, rtwvif_link->mac_addr);
 	arp_skb->sender_ip = rtwvif->ip_addr;
+	ether_addr_copy(arp_skb->target_hw, rtwvif_link->mac_addr);
+	arp_skb->target_ip = rtwvif->ip_addr;
 
 	return skb;
 }
@@ -9617,7 +9619,7 @@ int rtw89_fw_h2c_keep_alive(struct rtw89_dev *rtwdev, struct rtw89_vif_link *rtw
 
 	if (enable) {
 		ret = rtw89_fw_h2c_add_general_pkt(rtwdev, rtwvif_link,
-						   RTW89_PKT_OFLD_TYPE_NULL_DATA,
+						   RTW89_PKT_OFLD_TYPE_ARP_RSP,
 						   &pkt_id);
 		if (ret)
 			return -EPERM;
-- 
2.25.1