[PATCH 08/23] wifi: mt76: mt7925: add NDC-aware TX GTK table for NAN_DATA

[Sean Wang <sean.wang@kernel.org>]

From: Chengwei Yu <chengwei.yu@mediatek.com>

NAN TX GTK is NDC-scoped: every station in the same NAN Data Cluster
shares one key, and a single NAN_DATA vif can join multiple NDCs
concurrently. Add mt792x_nan.nan_tx_gtk_table[] (up to
MT792X_MAX_NAN_NDC = 8 RCU on-demand entries, one per NDC) and route
interface-directed NAN_DATA multicast through the matching WTBL in
mt792x_tx(), falling back to the interface WTBL when no entry exists.

Teardown lives in mt7925_remove_interface(), not the shared
mt792x_remove_interface(): NAN_DATA vifs are mt7925-only so cleanup
in the shared path would never run.

NOTE: NDC selection from skb context is not yet implemented; the
lookup always picks the first installed entry until mt7925_nan_set_key()
populates the table.

Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Chengwei Yu <chengwei.yu@mediatek.com>
---
 .../net/wireless/mediatek/mt76/mt7925/main.c  | 36 +++++++++++
 drivers/net/wireless/mediatek/mt76/mt792x.h   | 64 ++++++++++++++++++-
 .../net/wireless/mediatek/mt76/mt792x_core.c  | 27 ++++++--
 3 files changed, 122 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
index 2d3bf7d806a7..1b253989f43b 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
@@ -486,12 +486,22 @@ mt7925_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 		INIT_DELAYED_WORK(&mvif->nan.mac_rand_work,
 				  mt7925_nan_mac_rand_work);
 
+	if (vif->type == NL80211_IFTYPE_NAN_DATA) {
+		/* nan_tx_gtk_table[] slots are NULL from mac80211's kzalloc of
+		 * drv_priv; entries are allocated on demand by set_key when a
+		 * TX GTK is installed.
+		 */
+		spin_lock_init(&mvif->nan.nan_tx_gtk_lock);
+	}
 out:
 	mt792x_mutex_release(dev);
 
 	return ret;
 }
 
+static void mt7925_nan_gtk_table_cleanup(struct mt792x_dev *dev,
+					 struct mt792x_vif *mvif);
+
 static void
 mt7925_remove_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 {
@@ -516,6 +526,9 @@ mt7925_remove_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 	mconf = mt792x_link_conf_to_mconf(&vif->bss_conf);
 	mt792x_mac_link_bss_remove(dev, mconf, &mvif->sta.deflink);
 
+	if (vif->type == NL80211_IFTYPE_NAN_DATA)
+		mt7925_nan_gtk_table_cleanup(dev, mvif);
+
 	mt792x_mutex_release(dev);
 }
 
@@ -1331,6 +1344,29 @@ static void mt7925_nan_wcid_free(struct mt76_dev *mdev, struct mt76_wcid *wcid)
 	wcid->idx = MT792x_WCID_IDX_UNSET;
 }
 
+/* Free all TX GTK WTBL entries for a NAN_DATA vif on interface teardown.
+ * Caller must hold dev->mt76.mutex.
+ */
+static void mt7925_nan_gtk_table_cleanup(struct mt792x_dev *dev,
+					 struct mt792x_vif *mvif)
+{
+	int i;
+
+	for (i = 0; i < MT792X_MAX_NAN_NDC; i++) {
+		struct mt792x_nan_gtk_entry *e;
+
+		e = rcu_dereference_protected(mvif->nan.nan_tx_gtk_table[i],
+					      lockdep_is_held(&dev->mt76.mutex));
+		if (!e)
+			continue;
+		rcu_assign_pointer(mvif->nan.nan_tx_gtk_table[i], NULL);
+		rcu_assign_pointer(dev->mt76.wcid[e->wcid.idx], NULL);
+		mt76_wcid_cleanup(&dev->mt76, &e->wcid);
+		mt76_wcid_mask_clear(dev->mt76.wcid_mask, e->wcid.idx);
+		kfree(e);
+	}
+}
+
 /* Release any lazily-allocated per-peer NAN group key WTBLs for a departing
  * station.  Called from mt7925_mac_link_sta_remove() after the primary WTBL
  * is already freed, so the NAN-specific cleanup is clearly separated from the
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x.h b/drivers/net/wireless/mediatek/mt76/mt792x.h
index 707ca24193f9..342733e1001c 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x.h
+++ b/drivers/net/wireless/mediatek/mt76/mt792x.h
@@ -155,7 +155,7 @@ struct mt792x_sta {
 	struct mt792x_sta_nan_sched nan_sched;
 
 	/* NAN per-peer group key WTBLs (allocated lazily when keys are installed)
-	 * Note: TX GTK is interface-level, see mt792x_vif->nan_tx_gtk_table
+	 * Note: TX GTK is interface-level, see mvif->nan.nan_tx_gtk_table
 	 */
 	struct mt76_wcid nan_rx_gtk_wcid;    /* NAN_DATA peer: RX GTK WTBL (per-peer) */
 	struct mt76_wcid nan_rx_igtk_wcid;   /* NAN peer: RX IGTK/BIGTK WTBL (per-peer) */
@@ -183,6 +183,60 @@ struct mt792x_nan_conf {
 	bool enable_dw_notification;
 };
 
+/*
+ * NAN WTBL layout (mt7925)
+ *
+ * TX scope -- determined by who shares the encrypting key:
+ *
+ *   mvif->sta.deflink.wcid          [NAN vif, interface-level]
+ *     TX IGTK/BIGTK: multicast management TX.  Shared by all NMI peers;
+ *     installed via the normal hardware key path (set_key fallback).
+ *
+ *   mvif->sta.deflink.wcid          [NAN_DATA vif, interface-level]
+ *     TX GTK fallback when nan.nan_tx_gtk_table[] has no entry for the NDC.
+ *
+ *   mvif->nan.nan_tx_gtk_table[i]->wcid [NAN_DATA vif, NDC-level, on-demand]
+ *     TX GTK: multicast data TX.  All peers in the same NAN Data Cluster
+ *     share one TX GTK; different NDCs use independent keys.  Each slot
+ *     is NULL until set_key installs a key for that NDC (up to
+ *     MT792X_MAX_NAN_NDC concurrent NDCs).
+ *     NOTE: currently returns -EOPNOTSUPP -- mac80211 does not pass an
+ *     NDC ID at set_key time, so the correct table slot cannot be
+ *     selected.
+ *
+ * RX scope -- always per-peer because each sender has its own key:
+ *
+ *   msta->deflink.wcid              [NMI or NDI peer, peer-level]
+ *     NM-TK (NMI unicast) or ND-TK (NDI unicast).
+ *
+ *   msta->nan_rx_gtk_wcid           [NDI peer under NAN_DATA vif, peer-level]
+ *     RX GTK: multicast data RX.  Keyidx 1-2; allocated lazily in set_key.
+ *
+ *   msta->nan_rx_igtk_wcid          [NMI peer under NAN vif, peer-level]
+ *     RX IGTK/BIGTK: multicast management RX.  Keyidx 4-7; allocated
+ *     lazily in set_key.
+ *
+ * Example -- 2 peers in different NDCs, full security (design intent):
+ *   1  NAN vif WTBL                 TX IGTK/BIGTK
+ *   1  NAN_DATA vif WTBL            TX GTK fallback
+ *   2  NMI peer WTBLs               NM-TK (one per peer)
+ *   2  NDI peer WTBLs               ND-TK (one per peer)
+ *   2  TX GTK WTBLs                 nan.nan_tx_gtk_table[], one per NDC
+ *   2  RX GTK WTBLs                 nan_rx_gtk_wcid, one per NDI peer
+ *   2  RX IGTK/BIGTK WTBLs          nan_rx_igtk_wcid, one per NMI peer
+ *  = 12 WTBLs total
+ *
+ * Maximum concurrent NDCs is based on NAN_MAX_CONN_CFG (8 peers).
+ */
+#define MT792X_MAX_NAN_NDC	8
+
+/* TX GTK WTBL for one NAN Data Cluster; allocated only when the key is installed */
+struct mt792x_nan_gtk_entry {
+	u8 ndc_id[ETH_ALEN];
+	struct mt76_wcid wcid;
+	u8 key_idx;
+};
+
 struct mt792x_nan {
 	struct mt792x_nan_conf conf;
 
@@ -208,6 +262,14 @@ struct mt792x_nan {
 	 */
 	struct delayed_work mac_rand_work;
 	u32 mac_rand_period_sec;
+
+	/* NAN_DATA TX GTK table (mt7925 only): one entry per NAN Data Cluster,
+	 * allocated on demand when set_key installs a TX GTK for that NDC.
+	 * Protected by nan_tx_gtk_lock; slots are NULL until populated.
+	 */
+	struct mt792x_nan_gtk_entry __rcu *nan_tx_gtk_table[MT792X_MAX_NAN_NDC];
+	/* Protects nan_tx_gtk_table. */
+	spinlock_t nan_tx_gtk_lock;
 };
 
 struct mt792x_vif {
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_core.c b/drivers/net/wireless/mediatek/mt76/mt792x_core.c
index 0ad33f74c228..c8e42447f43a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x_core.c
+++ b/drivers/net/wireless/mediatek/mt76/mt792x_core.c
@@ -187,11 +187,30 @@ void mt792x_tx(struct ieee80211_hw *hw, struct ieee80211_tx_control *control,
 		wcid = &mlink->wcid;
 	}
 
+	/* NAN_DATA multicast: route through the NDC-specific TX GTK WTBL.
+	 * Full WTBL layout is documented in mt792x.h.
+	 * NOTE: NDC selection is not yet implemented; always falls back to
+	 * the interface WTBL until set_key populates nan_tx_gtk_table[].
+	 */
 	if (vif && !control->sta) {
-		struct mt792x_vif *mvif;
-
-		mvif = (struct mt792x_vif *)vif->drv_priv;
-		wcid = &mvif->sta.deflink.wcid;
+		struct mt792x_vif *mvif = (struct mt792x_vif *)vif->drv_priv;
+
+		if (vif->type == NL80211_IFTYPE_NAN_DATA) {
+			struct mt792x_nan_gtk_entry *entry = NULL;
+			int i;
+
+			rcu_read_lock();
+			for (i = 0; i < MT792X_MAX_NAN_NDC; i++) {
+				entry = rcu_dereference(mvif->nan.nan_tx_gtk_table[i]);
+				if (entry)
+					break;
+			}
+			rcu_read_unlock();
+
+			wcid = entry ? &entry->wcid : &mvif->sta.deflink.wcid;
+		} else {
+			wcid = &mvif->sta.deflink.wcid;
+		}
 	}
 
 	if (vif && control->sta && ieee80211_vif_is_mld(vif) &&
-- 
2.43.0