nl80211: Fix simultaneous scanning failure in case of MLO

Currently only one scan can be performed on per phy level at a time in
the driver. Due to this, if another scan request is sent via anoother
underlying phy, the kernel returns -EBUSY. This would result in hostapd
trying to set the interface into station mode if it was originally in AP
mode and retry sending a scan request. However, this behavior 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 the 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 <quic_adisi@quicinc.com>

diff --git a/src/drivers/driver_nl80211_scan.c b/src/drivers/driver_nl80211_scan.c
index 9a1e36f32ec04991378c7a3b30d25c42c63c1ecf..d0ed7ad956e7d6ee50f03eeb0f6804aff7696212 100644 (file)
--- a/src/drivers/driver_nl80211_scan.c
+++ b/src/drivers/driver_nl80211_scan.c
@@ -416,6 +416,40 @@ int wpa_driver_nl80211_scan(struct i802_bss *bss,
                wpa_printf(MSG_DEBUG, "nl80211: Scan trigger failed: ret=%d "
                           "(%s)", ret, strerror(-ret));
                if (drv->hostapd && is_ap_interface(drv->nlmode)) {
+#ifdef CONFIG_IEEE80211BE
+                       /* For multi link BSS, retry scan if any other links
+                        * are busy scanning. */
+                       if (ret == -EBUSY &&
+                           nl80211_link_valid(bss->valid_links,
+                                              params->link_id)) {
+                               struct i802_bss *link_bss;
+                               u8 link_id;
+
+                               wpa_printf(MSG_DEBUG,
+                                          "nl80211: Scan trigger on multi link BSS failed (requested link=%d on interface %s)",
+                                          params->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: BSS information already running scan not available");
+                                       goto fail;
+                               }
+
+                               link_id = nl80211_get_link_id_from_link(
+                                       link_bss, link_bss->scan_link);
+                               wpa_printf(MSG_DEBUG,
+                                          "nl80211: Scan already running on interface %s link %d",
+                                          link_bss->ifname, link_id);
+                               goto fail;
+                       }
+#endif /* CONFIG_IEEE80211BE */
+
                        /*
                         * mac80211 does not allow scan requests in AP mode, so
                         * try to do this in station mode.