[PATCH] netdev: handle disconnect event during the 4-way handshake

[James Prestwood <prestwoj@gmail.com>]

If a disconnect arrives during the 4-way handshake this would result
in netdev sending a disconnect event to station. If this is a
reassociation this case is unhandled in station and causes a hang as
it expects any connection failure to be handled via the reassociation
callback, not a random disconnect event.

To handle this case the disconnect event can check if there is a
pending connect callback and call that instead of the event handler.

Below are logs showing the "Unexpected disconnect event" which
prevents IWD from cleaning up its state and ultimately results in a
hang:

Jul 16 18:16:13: src/station.c:station_transition_reassociate()
Jul 16 18:16:13: event: state, old: connected, new: roaming
Jul 16 18:16:13: src/wiphy.c:wiphy_radio_work_done() Work item 65 done
Jul 16 18:16:13: src/wiphy.c:wiphy_radio_work_next() Starting work item 66
Jul 16 18:16:13: src/netdev.c:netdev_mlme_notify() MLME notification Del Station(20)
Jul 16 18:16:13: src/netdev.c:netdev_link_notify() event 16 on ifindex 6
Jul 16 18:16:13: src/netdev.c:netdev_mlme_notify() MLME notification Deauthenticate(39)
Jul 16 18:16:13: src/netdev.c:netdev_deauthenticate_event()
Jul 16 18:16:13: src/netdev.c:netdev_mlme_notify() MLME notification New Station(19)
Jul 16 18:16:13: src/station.c:station_netdev_event() Associating
Jul 16 18:16:13: src/netdev.c:netdev_mlme_notify() MLME notification Authenticate(37)
Jul 16 18:16:13: src/netdev.c:netdev_authenticate_event()
Jul 16 18:16:13: src/netdev.c:netdev_mlme_notify() MLME notification Associate(38)
Jul 16 18:16:13: src/netdev.c:netdev_associate_event()
Jul 16 18:16:13: src/netdev.c:netdev_link_notify() event 16 on ifindex 6
Jul 16 18:16:13: src/netdev.c:netdev_mlme_notify() MLME notification Connect(46)
Jul 16 18:16:13: src/netdev.c:netdev_connect_event()
Jul 16 18:16:13: src/netdev.c:netdev_connect_event() aborting and ignore_connect_event not set, proceed
Jul 16 18:16:13: src/netdev.c:netdev_connect_event() expect_connect_failure not set, proceed
Jul 16 18:16:13: src/netdev.c:parse_request_ies()
Jul 16 18:16:13: src/netdev.c:netdev_connect_event() Request / Response IEs parsed
Jul 16 18:16:13: src/netdev.c:netdev_get_oci()
Jul 16 18:16:13: src/netdev.c:netdev_link_notify() event 16 on ifindex 6
Jul 16 18:16:13: src/netdev.c:netdev_link_notify() event 16 on ifindex 6
Jul 16 18:16:13: src/netdev.c:netdev_link_notify() event 16 on ifindex 6
Jul 16 18:16:13: src/netdev.c:netdev_get_oci_cb() Obtained OCI: freq: 5220, width: 3, center1: 5210, center2: 0
Jul 16 18:16:13: src/eapol.c:eapol_start()
Jul 16 18:16:13: src/netdev.c:netdev_unicast_notify() Unicast notification Control Port Frame(129)
Jul 16 18:16:13: src/netdev.c:netdev_control_port_frame_event()
Jul 16 18:16:13: src/eapol.c:eapol_handle_ptk_1_of_4() ifindex=6
Jul 16 18:16:13: src/netdev.c:netdev_mlme_notify() MLME notification Control Port TX Status(139)
Jul 16 18:16:14: src/netdev.c:netdev_mlme_notify() MLME notification Notify CQM(64)
Jul 16 18:16:14: src/netdev.c:netdev_cqm_event() Signal change event (above=1 signal=-60)
Jul 16 18:16:17: src/netdev.c:netdev_link_notify() event 16 on ifindex 6
Jul 16 18:16:17: src/netdev.c:netdev_mlme_notify() MLME notification Del Station(20)
Jul 16 18:16:17: src/netdev.c:netdev_mlme_notify() MLME notification Deauthenticate(39)
Jul 16 18:16:17: src/netdev.c:netdev_deauthenticate_event()
Jul 16 18:16:17: src/netdev.c:netdev_mlme_notify() MLME notification Disconnect(48)
Jul 16 18:16:17: src/netdev.c:netdev_disconnect_event()
Jul 16 18:16:17: Received Deauthentication event, reason: 15, from_ap: true
Jul 16 18:16:17: src/wiphy.c:wiphy_radio_work_done() Work item 66 done
Jul 16 18:16:17: src/station.c:station_disconnect_event() 6
Jul 16 18:16:17: Unexpected disconnect event
Jul 16 18:16:17: src/netdev.c:netdev_link_notify() event 16 on ifindex 6
Jul 16 18:16:17: src/wiphy.c:wiphy_reg_notify() Notification of command Reg Change(36)
Jul 16 18:16:17: src/wiphy.c:wiphy_update_reg_domain() New reg domain country code for (global) is XX
---
 src/netdev.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/netdev.c b/src/netdev.c
index 7a335894..c6be05b5 100644
--- a/src/netdev.c
+++ b/src/netdev.c
@@ -1270,6 +1270,8 @@ static void netdev_disconnect_event(struct l_genl_msg *msg,
 	uint16_t reason_code = 0;
 	bool disconnect_by_ap = false;
 	netdev_event_func_t event_filter;
+	netdev_connect_cb_t connect_cb;
+	void *user_data;
 	void *event_data;
 
 	l_debug("");
@@ -1310,9 +1312,20 @@ static void netdev_disconnect_event(struct l_genl_msg *msg,
 
 	event_filter = netdev->event_filter;
 	event_data = netdev->user_data;
+	connect_cb = netdev->connect_cb;
+	user_data = netdev->user_data;
 	netdev_connect_free(netdev);
 
-	if (!event_filter)
+	/*
+	 * If a deauth frame come in after the connect event during the 4-way
+	 * handshake we need to handle this via the connect callback since its
+	 * still effectively a connection failure.
+	 */
+	if (connect_cb) {
+		connect_cb(netdev, NETDEV_RESULT_AUTHENTICATION_FAILED,
+				&reason_code, user_data);
+		return;
+	} else if (!event_filter)
 		return;
 
 	if (disconnect_by_ap)
-- 
2.34.1