[PATCH 6/7] station: separate FT-over-DS stages

[James Prestwood <prestwoj@gmail.com>]

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FT-over-DS was refactored to separate the FT action frame and
reassociation. From stations standpoint IWD needs to call
netdev_fast_transition_over_ds_action prior to actually roaming.
For now these two stages are being combined and the action
roam happens immediately after the action response callback.
---
 src/station.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 4 deletions(-)

diff --git a/src/station.c b/src/station.c
index 9254ec90..79ba23dc 100644
--- a/src/station.c
+++ b/src/station.c
@@ -112,6 +112,7 @@ struct station {
 	bool ap_directed_roaming : 1;
 	bool scanning : 1;
 	bool autoconnect : 1;
+	bool ft_over_ds : 1;
 };
 
 struct anqp_entry {
@@ -1625,10 +1626,17 @@ static void station_roam_failed(struct station *station)
 	l_debug("%u", netdev_get_ifindex(station->netdev));
 
 	/*
-	 * If we attempted a reassociation or a fast transition, and ended up
-	 * here then we are now disconnected.
+	 * If we attempted a reassociation or a fast transition (except DS),
+	 * and ended up here then we are now disconnected. In the case of
+	 * FT over DS we can remain connected to the AP even if the transition
+	 * fails.
 	 */
 	if (station->state == STATION_STATE_ROAMING) {
+		if (station->ft_over_ds) {
+			station_enter_state(station, STATION_STATE_CONNECTED);
+			goto delayed_retry;
+		}
+
 		station_disassociated(station);
 		return;
 	}
@@ -1657,6 +1665,7 @@ delayed_retry:
 	station->preparing_roam = false;
 	station->roam_scan_full = false;
 	station->ap_directed_roaming = false;
+	station->ft_over_ds = false;
 
 	if (station->signal_low)
 		station_roam_timeout_rearm(station, roam_retry_interval);
@@ -1742,6 +1751,42 @@ static bool bss_match_bssid(const void *a, const void *b)
 	return !memcmp(bss->addr, bssid, sizeof(bss->addr));
 }
 
+static void station_fast_transition_ds_cb(struct netdev *netdev,
+					uint16_t status, const uint8_t *bssid,
+					void *user_data)
+{
+	struct station *station = user_data;
+	struct scan_bss *bss;
+
+	if (status != 0)
+		goto failed;
+
+	/*
+	 * TODO: In the future it may be desired to start sending out these
+	 * FT-over-DS action frames at the time of connecting then be able to
+	 * roam immediately when required. If this is being done we can simply
+	 * bail out now as ft already caches the entires. But since this was
+	 * initiated due to a need to roam, do so now.
+	 */
+
+	/* Make sure we still have our BSS */
+	bss = l_queue_find(station->bss_list, bss_match_bssid, bssid);
+	if (!bss)
+		goto failed;
+
+	l_debug("Starting FT-over-DS roam");
+
+	if (netdev_fast_transition_over_ds(station->netdev, bss,
+					station_fast_transition_cb,
+					station) < 0)
+		goto failed;
+
+	return;
+
+failed:
+	station_roam_failed(station);
+}
+
 static void station_preauthenticate_cb(struct netdev *netdev,
 					enum netdev_result result,
 					const uint8_t *pmk, void *user_data)
@@ -1839,8 +1884,11 @@ static void station_transition_start(struct station *station,
 		/* FT-over-DS can be better suited for these situations */
 		if ((hs->mde[4] & 1) && (station->ap_directed_roaming ||
 				station->signal_low)) {
-			if (netdev_fast_transition_over_ds(station->netdev, bss,
-					station_fast_transition_cb,
+			station->ft_over_ds = true;
+
+			if (netdev_fast_transition_over_ds_action(
+					station->netdev, bss,
+					station_fast_transition_ds_cb,
 					station) < 0) {
 				station_roam_failed(station);
 				return;
-- 
2.26.2