mac80211: upgrade passive scan to active scan on DFS channels after beacon rx

commit b041b7b9de6e1d4362de855ab90f9d03ef323edd upstream.

In client mode, we can't connect to hidden SSID APs or SSIDs not advertised
in beacons on DFS channels, since we're forced to passive scan. Fix this by
sending out a probe request immediately after the first beacon, if active
scan was requested by the user.

Cc: stable@vger.kernel.org
Reported-by: Catrinel Catrinescu <cc@80211.de>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20220420104907.36275-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index d30bd21..f7bea4a 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1129,6 +1129,9 @@ struct tpt_led_trigger {
  *     a scan complete for an aborted scan.
  * @SCAN_HW_CANCELLED: Set for our scan work function when the scan is being
  *     cancelled.
+ * @SCAN_BEACON_WAIT: Set whenever we're passive scanning because of radar/no-IR
+ *     and could send a probe request after receiving a beacon.
+ * @SCAN_BEACON_DONE: Beacon received, we can now send a probe request
  */
 enum {
        SCAN_SW_SCANNING,
@@ -1137,6 +1140,8 @@ enum {
        SCAN_COMPLETED,
        SCAN_ABORTED,
        SCAN_HW_CANCELLED,
+       SCAN_BEACON_WAIT,
+       SCAN_BEACON_DONE,
 };
 
 /**

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 6b50cb5..887f945 100644 (file)
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -277,6 +277,16 @@ void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
        if (likely(!sdata1 && !sdata2))
                return;
 
+       if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
+               /*
+                * we were passive scanning because of radar/no-IR, but
+                * the beacon/proberesp rx gives us an opportunity to upgrade
+                * to active scan
+                */
+                set_bit(SCAN_BEACON_DONE, &local->scanning);
+                ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
+       }
+
        if (ieee80211_is_probe_resp(mgmt->frame_control)) {
                struct cfg80211_scan_request *scan_req;
                struct cfg80211_sched_scan_request *sched_scan_req;
@@ -783,6 +793,8 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
                                                IEEE80211_CHAN_RADAR)) ||
                    !req->n_ssids) {
                        next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
+                       if (req->n_ssids)
+                               set_bit(SCAN_BEACON_WAIT, &local->scanning);
                } else {
                        ieee80211_scan_state_send_probe(local, &next_delay);
                        next_delay = IEEE80211_CHANNEL_TIME;
@@ -994,6 +1006,8 @@ set_channel:
            !scan_req->n_ssids) {
                *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
                local->next_scan_state = SCAN_DECISION;
+               if (scan_req->n_ssids)
+                       set_bit(SCAN_BEACON_WAIT, &local->scanning);
                return;
        }
 
@@ -1086,6 +1100,8 @@ void ieee80211_scan_work(struct work_struct *work)
                        goto out;
        }
 
+       clear_bit(SCAN_BEACON_WAIT, &local->scanning);
+
        /*
         * as long as no delay is required advance immediately
         * without scheduling a new work
@@ -1096,6 +1112,10 @@ void ieee80211_scan_work(struct work_struct *work)
                        goto out_complete;
                }
 
+               if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
+                   local->next_scan_state == SCAN_DECISION)
+                       local->next_scan_state = SCAN_SEND_PROBE;
+
                switch (local->next_scan_state) {
                case SCAN_DECISION:
                        /* if no more bands/channels left, complete scan */