From cd6e32bf90f51f278f564a84dab4bc8babdf7f54 Mon Sep 17 00:00:00 2001
From: James Prestwood <james.prestwood@linux.intel.com>
Date: Fri, 1 Mar 2019 10:55:04 -0800
Subject: [PATCH] station: temporarily blacklist BSS for certain status codes

Several Auth/Assoc failure status codes indicate that the connection
failed for reasons such as bandwidth issues, poor channel conditions
etc. These conditions should not result in the BSS being blacklisted
since its likely only a temporary issue and the AP is not actually
"broken" per-se.

This adds support in station.c to temporarily blacklist these BSS's
on a per-network basis. After the connection has completed we clear
out these blacklist entries.
---
 src/station.c | 60 +++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 14 deletions(-)

diff --git a/src/station.c b/src/station.c
index 69c30b29..f7f3fa97 100644
--- a/src/station.c
+++ b/src/station.c
@@ -1617,8 +1617,6 @@ static bool station_try_next_bss(struct station *station)
 	struct scan_bss *next;
 	int ret;
 
-	blacklist_add_bss(station->connected_bss->addr);
-
 	next = network_bss_select(station->connected_network, false);
 
 	if (!next)
@@ -1634,20 +1632,52 @@ static bool station_try_next_bss(struct station *station)
 	return true;
 }
 
-static bool station_can_retry(uint16_t status_code)
+static bool station_retry_with_reason(struct station *station,
+					uint16_t reason_code)
 {
 	/*
 	 * We dont want to cause a retry and blacklist if the password was
 	 * incorrect. Otherwise we would just continue to fail.
 	 *
-	 * Other status codes can be added here if its decided we want to
+	 * Other reason codes can be added here if its decided we want to
 	 * fail in those cases.
 	 */
-	if (status_code != MMPDU_REASON_CODE_PREV_AUTH_NOT_VALID &&
-			status_code != MMPDU_REASON_CODE_IEEE8021X_FAILED)
-		return true;
+	if (reason_code == MMPDU_REASON_CODE_PREV_AUTH_NOT_VALID ||
+			reason_code == MMPDU_REASON_CODE_IEEE8021X_FAILED)
+		return false;
 
-	return false;
+	blacklist_add_bss(station->connected_bss->addr);
+
+	return station_try_next_bss(station);
+}
+
+/* A bit more consise for trying to fit these into 80 characters */
+#define IS_TEMPORARY_STATUS(code) \
+	((code) == MMPDU_STATUS_CODE_DENIED_UNSUFFICIENT_BANDWIDTH || \
+	(code) == MMPDU_STATUS_CODE_DENIED_POOR_CHAN_CONDITIONS || \
+	(code) == MMPDU_STATUS_CODE_REJECTED_WITH_SUGG_BSS_TRANS || \
+	(code) == MMPDU_STATUS_CODE_DENIED_NO_MORE_STAS)
+
+static bool station_retry_with_status(struct station *station,
+					uint16_t status_code)
+{
+	/*
+	 * Certain Auth/Assoc failures should not cause a timeout blacklist.
+	 * In these cases we want to only temporarily blacklist the BSS until
+	 * the connection is complete.
+	 *
+	 * TODO: The WITH_SUGG_BSS_TRANS case should also include a neighbor
+	 *       report IE in the frame. This would allow us to target a
+	 *       specific BSS on our next attempt. There is currently no way to
+	 *       obtain that IE, but this should be done in the future.
+	 */
+	if (IS_TEMPORARY_STATUS(status_code))
+		network_blacklist_add(station->connected_network,
+						station->connected_bss);
+	else
+		blacklist_add_bss(station->connected_bss->addr);
+
+	return station_try_next_bss(station);
 }
 
 static void station_connect_dbus_reply(struct station *station,
@@ -1684,15 +1714,17 @@ static void station_connect_cb(struct netdev *netdev, enum netdev_result result,
 		break;
 	case NETDEV_RESULT_HANDSHAKE_FAILED:
 		/* reason code in this case */
-		if (!station_can_retry(l_get_u16(event_data)))
-			break;
-		/* fall through */
+		if (station_retry_with_reason(station, l_get_u16(event_data)))
+			return;
+
+		break;
 	case NETDEV_RESULT_AUTHENTICATION_FAILED:
 	case NETDEV_RESULT_ASSOCIATION_FAILED:
-		/* Maybe there is another BSS under the same network? */
-		if (station_try_next_bss(station))
+		/* status code in this case */
+		if (station_retry_with_status(station, l_get_u16(event_data)))
 			return;
-		/* fall through */
+
+		break;
 	default:
 		break;
 	}