| Message ID | 20231030134837.452957-5-prestwoj@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Packet/beacon loss roaming improvements | expand |
Hi James, On 10/30/23 08:48, James Prestwood wrote: > The packet loss handler puts a higher priority on roaming compared > to the low signal roam path. This is generally beneficial since this > event usually indicates some problem with the BSS and generally is > an indicator that a disconnect will follow sometime soon. > > But by immediately issuing a scan we run the risk of causing many > successive scans if more packet loss events arrive following > the roam scans (and if no candidates are found). Logs provided > further. > > To help with this handle the first event with priority and > immediately issue a roam scan. If another event comes in within a > certain timeframe (2 seconds) don't immediately scan, but instead > rearm the roam timer instead of issuing a scan. This also handles > the case of a low signal roam scan followed by a packet loss > event. Delaying the roam will at least provide some time for packets > to get out in between roam scans. > > Logs were snipped to be less verbose, but this cycled happened > 5 times prior. In total 7 scans were issued in 5 seconds which may > very well have been the reason for the local disconnect: > > Oct 27 16:23:46 src/station.c:station_roam_failed() 9 > Oct 27 16:23:46 src/wiphy.c:wiphy_radio_work_done() Work item 29 done > Oct 27 16:23:47 src/netdev.c:netdev_mlme_notify() MLME notification Notify CQM(64) > Oct 27 16:23:47 src/station.c:station_packets_lost() Packets lost event: 10 > Oct 27 16:23:47 src/station.c:station_roam_scan() ifindex: 9 > Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_insert() Inserting work item 30 > Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_next() Starting work item 30 > Oct 27 16:23:47 src/station.c:station_start_roam() Using cached neighbor report for roam > Oct 27 16:23:47 src/scan.c:scan_notify() Scan notification Trigger Scan(33) > Oct 27 16:23:47 src/scan.c:scan_request_triggered() Active scan triggered for wdev a > Oct 27 16:23:47 src/scan.c:scan_notify() Scan notification New Scan Results(34) > Oct 27 16:23:47 src/netdev.c:netdev_link_notify() event 16 on ifindex 9 > ... scan results ... > Oct 27 16:23:47 src/station.c:station_roam_failed() 9 > Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_done() Work item 30 done > Oct 27 16:23:47 src/netdev.c:netdev_mlme_notify() MLME notification Notify CQM(64) > Oct 27 16:23:47 src/station.c:station_packets_lost() Packets lost event: 10 > Oct 27 16:23:47 src/station.c:station_roam_scan() ifindex: 9 > Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_insert() Inserting work item 31 > Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_next() Starting work item 31 > Oct 27 16:23:47 src/station.c:station_start_roam() Using cached neighbor report for roam > Oct 27 16:23:47 src/scan.c:scan_notify() Scan notification Trigger Scan(33) > Oct 27 16:23:47 src/scan.c:scan_request_triggered() Active scan triggered for wdev a > Oct 27 16:23:48 src/scan.c:scan_notify() Scan notification New Scan Results(34) > Oct 27 16:23:48 src/netdev.c:netdev_link_notify() event 16 on ifindex 9 > ... scan results ... > Oct 27 16:23:48 src/station.c:station_roam_failed() 9 > Oct 27 16:23:48 src/wiphy.c:wiphy_radio_work_done() Work item 31 done > Oct 27 16:23:48 src/netdev.c:netdev_mlme_notify() MLME notification Notify CQM(64) > Oct 27 16:23:48 src/station.c:station_packets_lost() Packets lost event: 10 > Oct 27 16:23:48 src/station.c:station_roam_scan() ifindex: 9 > Oct 27 16:23:48 src/wiphy.c:wiphy_radio_work_insert() Inserting work item 32 > Oct 27 16:23:48 src/wiphy.c:wiphy_radio_work_next() Starting work item 32 > Oct 27 16:23:48 src/station.c:station_start_roam() Using cached neighbor report for roam > Oct 27 16:23:48 src/scan.c:scan_notify() Scan notification Trigger Scan(33) > Oct 27 16:23:48 src/scan.c:scan_request_triggered() Active scan triggered for wdev a > Oct 27 16:23:49 src/netdev.c:netdev_link_notify() event 16 on ifindex 9 > Oct 27 16:23:49 src/netdev.c:netdev_mlme_notify() MLME notification Del Station(20) > Oct 27 16:23:49 src/netdev.c:netdev_mlme_notify() MLME notification Deauthenticate(39) > Oct 27 16:23:49 src/netdev.c:netdev_deauthenticate_event() > Oct 27 16:23:49 src/netdev.c:netdev_mlme_notify() MLME notification Disconnect(48) > Oct 27 16:23:49 src/netdev.c:netdev_disconnect_event() > Oct 27 16:23:49 Received Deauthentication event, reason: 4, from_ap: false > --- > src/station.c | 28 +++++++++++++++++++++++++++- > 1 file changed, 27 insertions(+), 1 deletion(-) > Applied, thanks. Regards, -Denis
diff --git a/src/station.c b/src/station.c index 8c87b3e0..bab690b9 100644 --- a/src/station.c +++ b/src/station.c @@ -123,6 +123,8 @@ struct station { struct wiphy_radio_work_item ft_work; + uint64_t last_roam_scan; + bool preparing_roam : 1; bool roam_scan_full : 1; bool signal_low : 1; @@ -1708,6 +1710,7 @@ static void station_roam_state_clear(struct station *station) station->signal_low = false; station->roam_min_time.tv_sec = 0; station->netconfig_after_roam = false; + station->last_roam_scan = 0; if (station->roam_scan_id) scan_cancel(netdev_get_wdev_id(station->netdev), @@ -2711,6 +2714,8 @@ static int station_roam_scan(struct station *station, if (L_WARN_ON(scan_freq_set_isempty(params.freqs))) return -ENOTSUP; + station->last_roam_scan = l_time_now(); + station->roam_scan_id = scan_active_full(netdev_get_wdev_id(station->netdev), ¶ms, station_roam_scan_triggered, @@ -3330,10 +3335,13 @@ static void station_disconnect_event(struct station *station, void *event_data) l_warn("Unexpected disconnect event"); } -#define STATION_PKT_LOSS_THRESHOLD 10 +#define STATION_PKT_LOSS_THRESHOLD 10 +#define LOSS_ROAM_RATE_LIMIT 2 static void station_packets_lost(struct station *station, uint32_t num_pkts) { + uint64_t elapsed; + l_debug("Packets lost event: %u", num_pkts); if (num_pkts < STATION_PKT_LOSS_THRESHOLD) @@ -3344,6 +3352,24 @@ static void station_packets_lost(struct station *station, uint32_t num_pkts) station_debug_event(station, "packet-loss-roam"); + elapsed = l_time_diff(station->last_roam_scan, l_time_now()); + + /* + * If we just issued a roam scan, delay the roam to avoid constant + * scanning. + */ + if (LOSS_ROAM_RATE_LIMIT > l_time_to_secs(elapsed)) { + l_debug("Too many roam attempts in %u second timeframe, " + "delaying roam", LOSS_ROAM_RATE_LIMIT); + + if (station->roam_trigger_timeout) + return; + + station_roam_timeout_rearm(station, LOSS_ROAM_RATE_LIMIT); + + return; + } + station_start_roam(station); }