Merge pull request 'bes2600: pre-empt AP-deauth-6 with mac80211 reassoc on decrypt-fail storm' (#1) from bes2600/decrypt-storm-fast-recover into mobian

Reviewed-on: #1

bes2600/bes2600.h

@@ -596,6 +596,11 @@ struct bes2600_vif {
         unsigned long           rx_timestamp;
         u32                     cipherType;
 
+	/* Decrypt-storm fast-recover (Trigger B). See txrx.c. */
+	unsigned long			decrypt_storm_window_start;
+	unsigned int			decrypt_storm_count;
+	unsigned int			decrypt_storm_recoveries;
+	struct work_struct		decrypt_storm_recover_work;
 
 	/* AP powersave */
 	u32			link_id_map;
@@ -856,4 +861,8 @@ int bes2600_btusb_setup_pipes(struct sbus_priv *sbus_priv);
 void bes2600_btusb_uninit(struct usb_interface *interface);
 #endif
 
+/* Decrypt-storm fast-recover helpers — see txrx.c. */
+void bes2600_decrypt_storm_init(struct bes2600_vif *priv);
+void bes2600_decrypt_storm_account(struct bes2600_vif *priv);
+
 #endif /* BES2600_H */

bes2600/debug.c

@@ -542,6 +542,8 @@ static int bes2600_status_show_priv(struct seq_file *seq, void *v)
 		priv->listening ? " (listening)" : "");
 	seq_printf(seq, "Assoc:      %s\n",
 		bes2600_debug_join_status[priv->join_status]);
+	seq_printf(seq, "DecryptStormRecoveries: %u\n",
+		   priv->decrypt_storm_recoveries);
 	if (priv->rx_filter.promiscuous)
 		seq_puts(seq,   "Filter:     promisc\n");
 	else if (priv->rx_filter.fcs)

bes2600/sta.c

@@ -448,6 +448,7 @@ void bes2600_remove_interface(struct ieee80211_hw *dev,
 	cancel_delayed_work_sync(&priv->join_timeout);
 	cancel_delayed_work_sync(&priv->set_cts_work);
 	cancel_delayed_work_sync(&priv->pending_offchanneltx_work);
+	cancel_work_sync(&priv->decrypt_storm_recover_work);
 
 	del_timer_sync(&priv->mcast_timeout);
 	/* TODO:COMBO: May be reset of these variables "delayed_link_loss and
@@ -2619,6 +2620,7 @@ int bes2600_vif_setup(struct bes2600_vif *priv)
 
 	/* Setup per vif workitems and locks */
 	spin_lock_init(&priv->vif_lock);
+	bes2600_decrypt_storm_init(priv);
 	INIT_WORK(&priv->join_work, bes2600_join_work);
 	INIT_DELAYED_WORK(&priv->join_timeout, bes2600_join_timeout);
 	INIT_WORK(&priv->unjoin_work, bes2600_unjoin_work);

bes2600/txrx.c

@@ -25,6 +25,78 @@
 
 #define BES2600_INVALID_RATE_ID (0xFF)
 
+/*
+ * Decrypt-storm fast-recover (Trigger B).
+ *
+ * When the BES2600 firmware reports WSM_STATUS_DECRYPTFAILURE for a
+ * burst of received frames (typically because the host's PTK or GTK
+ * has fallen out of sync with the AP), the AP eventually concludes that
+ * the STA is not authenticated and emits an unprotected deauth-reason-6
+ * ("Class 2 frame received from non-authenticated station"). On the
+ * deployed pinetab2 + bes2600 stack this AP-initiated deauth has been
+ * observed to leave the link blackholed for up to 109 s before
+ * userspace finds a different SSID/channel to recover on. (Receipts at
+ * https://git.reauktion.de/marfrit/besser, notes/phase5-2026-05-06.md.)
+ *
+ * Recovery here pre-empts the AP: when we see THRESHOLD decrypt
+ * failures within WINDOW, we ask mac80211 for a clean reassoc via
+ * ieee80211_connection_loss(), which causes immediate disassociation
+ * and lets userspace auto-reconnect with fresh keys.
+ *
+ * mac80211 contract: ieee80211_connection_loss() may be called
+ * regardless of IEEE80211_HW_CONNECTION_MONITOR; it causes immediate
+ * disassociation without driver-side recovery attempts. See
+ * include/net/mac80211.h for the canonical doc-comment.
+ *
+ * The threshold is set well above the steady-state per-vif
+ * decrypt-fail rate observed in measurement (~1/min even under
+ * sustained 1 MB/s load), so a true storm is required to trip it.
+ */
+#define BES2600_DECRYPT_STORM_THRESHOLD	5
+#define BES2600_DECRYPT_STORM_WINDOW_MS	5000
+
+static void bes2600_decrypt_storm_recover_work(struct work_struct *work)
+{
+	struct bes2600_vif *priv = container_of(work, struct bes2600_vif,
+						decrypt_storm_recover_work);
+
+	if (!priv->vif)
+		return;
+
+	bes_warn("[bes2600] decrypt-storm fast-recover: forcing reassoc\n");
+	ieee80211_connection_loss(priv->vif);
+	priv->decrypt_storm_recoveries++;
+}
+
+void bes2600_decrypt_storm_init(struct bes2600_vif *priv)
+{
+	INIT_WORK(&priv->decrypt_storm_recover_work,
+		  bes2600_decrypt_storm_recover_work);
+	priv->decrypt_storm_window_start = 0;
+	priv->decrypt_storm_count = 0;
+	priv->decrypt_storm_recoveries = 0;
+}
+
+void bes2600_decrypt_storm_account(struct bes2600_vif *priv)
+{
+	unsigned long now = jiffies;
+	unsigned long window = msecs_to_jiffies(BES2600_DECRYPT_STORM_WINDOW_MS);
+
+	if (priv->decrypt_storm_window_start == 0 ||
+	    time_after(now, priv->decrypt_storm_window_start + window)) {
+		priv->decrypt_storm_window_start = now;
+		priv->decrypt_storm_count = 1;
+		return;
+	}
+
+	if (++priv->decrypt_storm_count >= BES2600_DECRYPT_STORM_THRESHOLD) {
+		priv->decrypt_storm_count = 0;
+		/* Skew the window so we don't re-fire on the same storm. */
+		priv->decrypt_storm_window_start = now + window;
+		schedule_work(&priv->decrypt_storm_recover_work);
+	}
+}
+
 #ifdef CONFIG_BES2600_TESTMODE
 #include "bes_nl80211_testmode_msg.h"
 #endif /* CONFIG_BES2600_TESTMODE */
@@ -1672,6 +1744,8 @@ void bes2600_rx_cb(struct bes2600_vif *priv,
 			goto drop;
 		} else {
 			bes_warn("[RX] Receive failure: %d.\n", arg->status);
+			if (arg->status == WSM_STATUS_DECRYPTFAILURE)
+				bes2600_decrypt_storm_account(priv);
 			goto drop;
 		}
 	}