From 1bf64ee6e25ff8256337bfe9c13ceaf27c06c2aa Mon Sep 17 00:00:00 2001 From: Aditya Kumar Singh Date: Wed, 1 Nov 2023 22:36:40 +0530 Subject: [PATCH 3/4] hostapd: fix simultaneous scanning failure in case of MLO Currently only 1 scan can be performed on per phy level at a time in mac80211. Due to this, if via other underlying radio, a scan request is sent, kernel returns -EBUSY. And then hostapd would try to set the interface in station mode if it was originally in AP mode and retry sending a scan request. However, this behaviour is expected in case of multi link operation and hence there is no need to switch the mode as such. Hence, add logic to not change the nl mode if kernel returns -EBUSY during multi link AP operation. The caller can accordingly decide and if needed, it can re-schedule a scan request after some time. Signed-off-by: Aditya Kumar Singh --- src/drivers/driver_nl80211_scan.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/src/drivers/driver_nl80211_scan.c b/src/drivers/driver_nl80211_scan.c index 5173accf2338..a5fe955555b1 100644 --- a/src/drivers/driver_nl80211_scan.c +++ b/src/drivers/driver_nl80211_scan.c @@ -398,6 +398,30 @@ int wpa_driver_nl80211_scan(struct i802_bss *bss, if (drv->hostapd && is_ap_interface(drv->nlmode)) { enum nl80211_iftype old_mode = drv->nlmode; + /* For Multi Link BSS, retry scan if any other links are busy scanning */ + if (ret == -EBUSY && nl80211_link_valid(bss, params->mlo_link_id)) { + struct i802_bss *link_bss; + + wpa_printf(MSG_DEBUG, + "nl80211: Scan trigger on Multi Link BSS failed (requested link=%d interface %s)", + params->mlo_link_id, bss->ifname); + + for (link_bss = drv->first_bss; link_bss; link_bss = link_bss->next) + if (link_bss->scan_link) + break; + + if (!link_bss) { + wpa_printf(MSG_DEBUG, + "nl80211: Interface information already running scan not available"); + goto fail; + } + + wpa_printf(MSG_DEBUG, + "nl80211: Scan already running on interface %s link %d", + link_bss->ifname, link_bss->scan_link->link_id); + goto fail; + } + /* * mac80211 does not allow scan requests in AP mode, so * try to do this in station mode. -- 2.17.1