policy: avoid creating kick loop for client

When checking whether a client is allowed to associate to a node, the
lower ceiling for kicking clients was not taken into account when
assoc-steering is disabled.

The problem behind this is, that a configured lower barrier for
disassociating clients (kicking) would kick the client immediatly after
association. In the worst scenario the client immediatly associates
again to the station and ends up in a kick loop.

Don't allow associating when a min_snr is configured and the client
signal is below this value.

Signed-off-by: David Bauer <mail@david-bauer.net>

diff --git a/policy.c b/policy.c
index 1b4fa57abda385e30691e1a9c2091b20de0496aa..76cf1e335a526c235cfb6cfc2acb9940ce2409ab 100644 (file)
--- a/policy.c
+++ b/policy.c
@@ -155,8 +155,22 @@ usteer_check_request(struct sta_info *si, enum usteer_event_type type)
        if (type == EVENT_TYPE_AUTH)
                goto out;
 
-       if (type == EVENT_TYPE_ASSOC && !config.assoc_steering)
-               goto out;
+       if (type == EVENT_TYPE_ASSOC) {
+               /* Check if assoc request has lower signal than min_signal.
+                * If this is the case, block assoc even when assoc steering is enabled.
+                *
+                * Otherwise, the client potentially ends up in a assoc - kick loop.
+                */
+               if (config.min_snr && si->signal < snr_to_signal(si->node, config.min_snr)) {
+                       ev.reason = UEV_REASON_LOW_SIGNAL;
+                       ev.threshold.cur = si->signal;
+                       ev.threshold.ref = min_signal;
+                       ret = false;
+                       goto out;
+               } else if (!config.assoc_steering) {
+                       goto out;
+               }
+       }
 
        min_signal = snr_to_signal(si->node, config.min_connect_snr);
        if (si->signal < min_signal) {