From: James Prestwood <prestwoj@gmail.com>
To: iwd@lists.linux.dev
Cc: James Prestwood <prestwoj@gmail.com>
Subject: [PATCH v2 1/2] station: start roam on beacon loss event
Date: Tue, 7 Nov 2023 06:11:39 -0800 [thread overview]
Message-ID: <20231107141140.1706441-1-prestwoj@gmail.com> (raw)
Beacon loss handling was removed in the past because it was
determined that this even always resulted in a disconnect. This
was short sighted and not always true. The default kernel behavior
waits for 7 lost beacons before emitting this event, then sends
either a few nullfuncs or probe requests to the BSS to determine
if its really gone. If these come back successfully the connection
will remain alive. This can give IWD some time to roam in some
cases so we should be handling this event.
Since beacon loss indicates a very poor connection the roam scan
is delayed by a few seconds in order to give the kernel a chance
to send the nullfuncs/probes or receive more beacons. This may
result in a disconnect, but it would have happened anyways.
Attempting a roam mainly handles the case when the connection can
be maintained after beacon loss, but is still poor.
---
src/netdev.h | 1 +
src/station.c | 18 ++++++++++++++++++
2 files changed, 19 insertions(+)
v2:
* Delay the roam to give the kernel a chance to salvage the
connection
FYI, I did attempt to add back the beacon loss test without much
luck. Blocking beacons with hwsim did not result in a beacon loss
event which may have been one of the reasons it was removed in the
first place. Even blocking _all_ frames doesn't result in an event
but instead just a local disconnect.
After looking more into it I see that actually only a few drivers
even use ieee80211_beacon_loss/ieee80211_connection_loss:
iwlwifi,wl1251,intersil,mt76,wfx,ath10/11k,wcn36xx
Every other driver likely disconnects rather than attempts to
handle beacon loss. So probably for the majority of users this
actually didn't matter, but for these drivers it does make sense
to handle the event.
diff --git a/src/netdev.h b/src/netdev.h
index 73d38c32..f27130f1 100644
--- a/src/netdev.h
+++ b/src/netdev.h
@@ -51,6 +51,7 @@ enum netdev_event {
NETDEV_EVENT_RSSI_LEVEL_NOTIFY,
NETDEV_EVENT_PACKET_LOSS_NOTIFY,
NETDEV_EVENT_FT_ROAMED,
+ NETDEV_EVENT_BEACON_LOSS_NOTIFY,
};
enum netdev_watch_event {
diff --git a/src/station.c b/src/station.c
index 5a202ebd..c3f26b5a 100644
--- a/src/station.c
+++ b/src/station.c
@@ -3370,6 +3370,21 @@ static void station_packets_lost(struct station *station, uint32_t num_pkts)
station_start_roam(station);
}
+static void station_beacon_lost(struct station *station)
+{
+ l_debug("Beacon lost event");
+
+ if (station_cannot_roam(station))
+ return;
+
+ station_debug_event(station, "beacon-loss-roam");
+
+ if (station->roam_trigger_timeout)
+ return;
+
+ station_roam_timeout_rearm(station, LOSS_ROAM_RATE_LIMIT);
+}
+
static void station_netdev_event(struct netdev *netdev, enum netdev_event event,
void *event_data, void *user_data)
{
@@ -3414,6 +3429,9 @@ static void station_netdev_event(struct netdev *netdev, enum netdev_event event,
station_roamed(station);
break;
+ case NETDEV_EVENT_BEACON_LOSS_NOTIFY:
+ station_beacon_lost(station);
+ break;
}
}
--
2.25.1
next reply other threads:[~2023-11-07 14:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-07 14:11 James Prestwood [this message]
2023-11-07 14:11 ` [PATCH v2 2/2] netdev: handle/send beacon loss event James Prestwood
2023-11-07 15:45 ` [PATCH v2 1/2] station: start roam on " Denis Kenzior
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