wcn36xx: Add set_rekey_data callback

Add a callback for Group Temporal Key tracking as provided by the standard
WiFi ops structure.

We track the key to integrate GTK offloading into the WoWLAN suspend path
later on. Code comes from the Intel iwlwifi driver with minimal name
changes.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Benjamin Li <benl@squareup.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210605011140.2004643-8-bryan.odonoghue@linaro.org

drivers/net/wireless/ath/wcn36xx/main.c

@@ -1147,6 +1147,24 @@ static int wcn36xx_resume(struct ieee80211_hw *hw)
 	return 0;
 }
 
+static void wcn36xx_set_rekey_data(struct ieee80211_hw *hw,
+				   struct ieee80211_vif *vif,
+				   struct cfg80211_gtk_rekey_data *data)
+{
+	struct wcn36xx *wcn = hw->priv;
+	struct wcn36xx_vif *vif_priv = wcn36xx_vif_to_priv(vif);
+
+	mutex_lock(&wcn->conf_mutex);
+
+	memcpy(vif_priv->rekey_data.kek, data->kek, NL80211_KEK_LEN);
+	memcpy(vif_priv->rekey_data.kck, data->kck, NL80211_KCK_LEN);
+	vif_priv->rekey_data.replay_ctr =
+		cpu_to_le64(be64_to_cpup((__be64 *)data->replay_ctr));
+	vif_priv->rekey_data.valid = true;
+
+	mutex_unlock(&wcn->conf_mutex);
+}
+
 #endif
 
 static int wcn36xx_ampdu_action(struct ieee80211_hw *hw,
@@ -1249,6 +1267,7 @@ static const struct ieee80211_ops wcn36xx_ops = {
 #ifdef CONFIG_PM
 	.suspend		= wcn36xx_suspend,
 	.resume			= wcn36xx_resume,
+	.set_rekey_data		= wcn36xx_set_rekey_data,
 #endif
 	.config			= wcn36xx_config,
 	.prepare_multicast	= wcn36xx_prepare_multicast,

drivers/net/wireless/ath/wcn36xx/wcn36xx.h

@@ -143,6 +143,12 @@ struct wcn36xx_vif {
 	unsigned long tentative_addrs[BITS_TO_LONGS(WCN36XX_HAL_IPV6_OFFLOAD_ADDR_MAX)];
 	int num_target_ipv6_addrs;
 #endif
+	/* WoWLAN GTK rekey data */
+	struct {
+		u8 kck[NL80211_KCK_LEN], kek[NL80211_KEK_LEN];
+		__le64 replay_ctr;
+		bool valid;
+	} rekey_data;
 
 	struct list_head sta_list;
 };