wifi: rtw89: wow: add ARP offload feature

Add H2C command and offload template packet to allow firmware send ARP
response in WoWLAN mode. Then, firmware in WoWLAN mode can interactive
with peer that issue ARP request to query MAC address.
Signed-off-by: Chin-Yen Lee <timlee@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://msgid.link/20240502022505.28966-13-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/core.h

@@ -3390,6 +3390,7 @@ struct rtw89_vif {
 	u8 port;
 	u8 mac_addr[ETH_ALEN];
 	u8 bssid[ETH_ALEN];
+	__be32 ip_addr;
 	u8 phy_idx;
 	u8 mac_idx;
 	u8 net_type;

drivers/net/wireless/realtek/rtw89/fw.c

@@ -2,6 +2,7 @@
 /* Copyright(c) 2019-2020  Realtek Corporation
  */
 
+#include <linux/if_arp.h>
 #include "cam.h"
 #include "chan.h"
 #include "coex.h"
@@ -26,6 +27,17 @@ struct rtw89_sa_query {
 	u8 action;
 } __packed __aligned(2);
 
+struct rtw89_arp_rsp {
+	struct ieee80211_hdr_3addr addr;
+	u8 llc_hdr[sizeof(rfc1042_header)];
+	__be16 llc_type;
+	struct arphdr arp_hdr;
+	u8 sender_hw[ETH_ALEN];
+	__be32 sender_ip;
+	u8 target_hw[ETH_ALEN];
+	__be32 target_ip;
+} __packed __aligned(2);
+
 static const u8 mss_signature[] = {0x4D, 0x53, 0x53, 0x4B, 0x50, 0x4F, 0x4F, 0x4C};
 
 union rtw89_fw_element_arg {
@@ -2223,6 +2235,48 @@ static struct sk_buff *rtw89_sa_query_get(struct rtw89_dev *rtwdev,
 	return skb;
 }
 
+static struct sk_buff *rtw89_arp_response_get(struct rtw89_dev *rtwdev,
+					      struct rtw89_vif *rtwvif)
+{
+	struct rtw89_wow_param *rtw_wow = &rtwdev->wow;
+	struct rtw89_arp_rsp *arp_skb;
+	struct arphdr *arp_hdr;
+	struct sk_buff *skb;
+	__le16 fc;
+
+	skb = dev_alloc_skb(sizeof(struct rtw89_arp_rsp));
+	if (!skb)
+		return NULL;
+
+	arp_skb = skb_put_zero(skb, sizeof(*arp_skb));
+
+	if (rtw_wow->ptk_alg)
+		fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_FCTL_TODS |
+				 IEEE80211_FCTL_PROTECTED);
+	else
+		fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_FCTL_TODS);
+
+	arp_skb->addr.frame_control = fc;
+	ether_addr_copy(arp_skb->addr.addr1, rtwvif->bssid);
+	ether_addr_copy(arp_skb->addr.addr2, rtwvif->mac_addr);
+	ether_addr_copy(arp_skb->addr.addr3, rtwvif->bssid);
+
+	memcpy(arp_skb->llc_hdr, rfc1042_header, sizeof(rfc1042_header));
+	arp_skb->llc_type = htons(ETH_P_ARP);
+
+	arp_hdr = &arp_skb->arp_hdr;
+	arp_hdr->ar_hrd = htons(ARPHRD_ETHER);
+	arp_hdr->ar_pro = htons(ETH_P_IP);
+	arp_hdr->ar_hln = ETH_ALEN;
+	arp_hdr->ar_pln = 4;
+	arp_hdr->ar_op = htons(ARPOP_REPLY);
+
+	ether_addr_copy(arp_skb->sender_hw, rtwvif->mac_addr);
+	arp_skb->sender_ip = rtwvif->ip_addr;
+
+	return skb;
+}
+
 static int rtw89_fw_h2c_add_general_pkt(struct rtw89_dev *rtwdev,
 					struct rtw89_vif *rtwvif,
 					enum rtw89_fw_pkt_ofld_type type,
@@ -2256,6 +2310,9 @@ static int rtw89_fw_h2c_add_general_pkt(struct rtw89_dev *rtwdev,
 	case RTW89_PKT_OFLD_TYPE_SA_QUERY:
 		skb = rtw89_sa_query_get(rtwdev, rtwvif);
 		break;
+	case RTW89_PKT_OFLD_TYPE_ARP_RSP:
+		skb = rtw89_arp_response_get(rtwdev, rtwvif);
+		break;
 	default:
 		goto err;
 	}
@@ -6390,6 +6447,57 @@ int rtw89_fw_h2c_keep_alive(struct rtw89_dev *rtwdev, struct rtw89_vif *rtwvif,
 	return ret;
 }
 
+int rtw89_fw_h2c_arp_offload(struct rtw89_dev *rtwdev, struct rtw89_vif *rtwvif,
+			     bool enable)
+{
+	struct rtw89_h2c_arp_offload *h2c;
+	u32 len = sizeof(*h2c);
+	struct sk_buff *skb;
+	u8 pkt_id = 0;
+	int ret;
+
+	if (enable) {
+		ret = rtw89_fw_h2c_add_general_pkt(rtwdev, rtwvif,
+						   RTW89_PKT_OFLD_TYPE_ARP_RSP,
+						   &pkt_id);
+		if (ret)
+			return ret;
+	}
+
+	skb = rtw89_fw_h2c_alloc_skb_with_hdr(rtwdev, len);
+	if (!skb) {
+		rtw89_err(rtwdev, "failed to alloc skb for arp offload\n");
+		return -ENOMEM;
+	}
+
+	skb_put(skb, len);
+	h2c = (struct rtw89_h2c_arp_offload *)skb->data;
+
+	h2c->w0 = le32_encode_bits(enable, RTW89_H2C_ARP_OFFLOAD_W0_ENABLE) |
+		  le32_encode_bits(0, RTW89_H2C_ARP_OFFLOAD_W0_ACTION) |
+		  le32_encode_bits(rtwvif->mac_id, RTW89_H2C_ARP_OFFLOAD_W0_MACID) |
+		  le32_encode_bits(pkt_id, RTW89_H2C_ARP_OFFLOAD_W0_PKT_ID);
+
+	rtw89_h2c_pkt_set_hdr(rtwdev, skb, FWCMD_TYPE_H2C,
+			      H2C_CAT_MAC,
+			      H2C_CL_MAC_WOW,
+			      H2C_FUNC_ARP_OFLD, 0, 1,
+			      len);
+
+	ret = rtw89_h2c_tx(rtwdev, skb, false);
+	if (ret) {
+		rtw89_err(rtwdev, "failed to send h2c\n");
+		goto fail;
+	}
+
+	return 0;
+
+fail:
+	dev_kfree_skb_any(skb);
+
+	return ret;
+}
+
 #define H2C_DISCONNECT_DETECT_LEN 8
 int rtw89_fw_h2c_disconnect_detect(struct rtw89_dev *rtwdev,
 				   struct rtw89_vif *rtwvif, bool enable)

drivers/net/wireless/realtek/rtw89/fw.h

@@ -2025,6 +2025,17 @@ struct rtw89_h2c_wow_gtk_ofld {
 #define RTW89_H2C_WOW_GTK_OFLD_W1_PMF_BIP_SEC_ALGO GENMASK(9, 8)
 #define RTW89_H2C_WOW_GTK_OFLD_W1_ALGO_AKM_SUIT GENMASK(17, 10)
 
+struct rtw89_h2c_arp_offload {
+	__le32 w0;
+	__le32 w1;
+} __packed;
+
+#define RTW89_H2C_ARP_OFFLOAD_W0_ENABLE BIT(0)
+#define RTW89_H2C_ARP_OFFLOAD_W0_ACTION BIT(1)
+#define RTW89_H2C_ARP_OFFLOAD_W0_MACID GENMASK(23, 16)
+#define RTW89_H2C_ARP_OFFLOAD_W0_PKT_ID GENMASK(31, 24)
+#define RTW89_H2C_ARP_OFFLOAD_W1_CONTENT GENMASK(31, 0)
+
 enum rtw89_btc_btf_h2c_class {
 	BTFC_SET = 0x10,
 	BTFC_GET = 0x11,
@@ -3919,6 +3930,7 @@ enum rtw89_wow_h2c_func {
 	H2C_FUNC_DISCONNECT_DETECT	= 0x1,
 	H2C_FUNC_WOW_GLOBAL		= 0x2,
 	H2C_FUNC_GTK_OFLD		= 0x3,
+	H2C_FUNC_ARP_OFLD		= 0x4,
 	H2C_FUNC_WAKEUP_CTRL		= 0x8,
 	H2C_FUNC_WOW_CAM_UPD		= 0xC,
 	H2C_FUNC_AOAC_REPORT_REQ	= 0xD,
@@ -4436,6 +4448,8 @@ int rtw89_fw_h2c_wow_wakeup_ctrl(struct rtw89_dev *rtwdev,
 				 struct rtw89_vif *rtwvif, bool enable);
 int rtw89_fw_h2c_keep_alive(struct rtw89_dev *rtwdev, struct rtw89_vif *rtwvif,
 			    bool enable);
+int rtw89_fw_h2c_arp_offload(struct rtw89_dev *rtwdev,
+			     struct rtw89_vif *rtwvif, bool enable);
 int rtw89_fw_h2c_disconnect_detect(struct rtw89_dev *rtwdev,
 				   struct rtw89_vif *rtwvif, bool enable);
 int rtw89_fw_h2c_wow_global(struct rtw89_dev *rtwdev, struct rtw89_vif *rtwvif,

drivers/net/wireless/realtek/rtw89/mac80211.c

@@ -473,6 +473,9 @@ static void rtw89_ops_bss_info_changed(struct ieee80211_hw *hw,
 	if (changed & BSS_CHANGED_PS)
 		rtw89_recalc_lps(rtwdev);
 
+	if (changed & BSS_CHANGED_ARP_FILTER)
+		rtwvif->ip_addr = vif->cfg.arp_addr_list[0];
+
 	mutex_unlock(&rtwdev->mutex);
 }
 

drivers/net/wireless/realtek/rtw89/wow.c

@@ -1320,6 +1320,10 @@ static int rtw89_wow_fw_start(struct rtw89_dev *rtwdev)
 		goto out;
 	}
 
+	ret = rtw89_fw_h2c_arp_offload(rtwdev, rtwvif, true);
+	if (ret)
+		rtw89_warn(rtwdev, "wow: failed to enable arp offload\n");
+
 	ret = rtw89_wow_cfg_wake(rtwdev, true);
 	if (ret) {
 		rtw89_err(rtwdev, "wow: failed to config wake\n");
@@ -1362,6 +1366,10 @@ static int rtw89_wow_fw_stop(struct rtw89_dev *rtwdev)
 		goto out;
 	}
 
+	ret = rtw89_fw_h2c_arp_offload(rtwdev, rtwvif, false);
+	if (ret)
+		rtw89_warn(rtwdev, "wow: failed to disable arp offload\n");
+
 	rtw89_wow_key_clear(rtwdev);
 	rtw89_fw_release_general_pkt_list(rtwdev, true);