policy: only select nodes with better signal when roaming

When determining a new node within the roam state machine, require the
destination node to have a better reported signal from the client.

Otherwise, the roam state machine might trigger a roam action for a
unsuitable destination node.

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

diff --git a/policy.c b/policy.c
index b55757749eaedfa9d1fcd29fa187d984e6e0debd..08ab90204f75c8a786b55bc5741bba0fe4280743 100644 (file)
--- a/policy.c
+++ b/policy.c
@@ -95,7 +95,7 @@ is_better_candidate(struct sta_info *si_cur, struct sta_info *si_new)
 }
 
 static struct sta_info *
-find_better_candidate(struct sta_info *si_ref, struct uevent *ev)
+find_better_candidate(struct sta_info *si_ref, struct uevent *ev, uint32_t required_criteria)
 {
        struct sta_info *si;
        struct sta *sta = si_ref->sta;
@@ -118,6 +118,9 @@ find_better_candidate(struct sta_info *si_ref, struct uevent *ev)
                if (is_better_candidate(si, si_ref))
                        continue;
 
+               if (!(reasons & required_criteria))
+                       continue;
+
                if (ev) {
                        ev->si_other = si;
                        ev->select_reasons = reasons;
@@ -189,7 +192,7 @@ usteer_check_request(struct sta_info *si, enum usteer_event_type type)
                goto out;
        }
 
-       if (!find_better_candidate(si, &ev))
+       if (!find_better_candidate(si, &ev, 0))
                goto out;
 
        ev.reason = UEV_REASON_BETTER_CANDIDATE;
@@ -272,7 +275,7 @@ usteer_roam_trigger_sm(struct sta_info *si)
                if (current_time - si->roam_event < config.roam_scan_interval)
                        break;
 
-               if (find_better_candidate(si, &ev) ||
+               if (find_better_candidate(si, &ev, (1 << UEV_SELECT_REASON_SIGNAL)) ||
                    si->roam_scan_done > si->roam_event) {
                        usteer_roam_set_state(si, ROAM_TRIGGER_SCAN_DONE, &ev);
                        break;
@@ -289,7 +292,7 @@ usteer_roam_trigger_sm(struct sta_info *si)
                break;
 
        case ROAM_TRIGGER_IDLE:
-               if (find_better_candidate(si, &ev)) {
+               if (find_better_candidate(si, &ev, (1 << UEV_SELECT_REASON_SIGNAL))) {
                        usteer_roam_set_state(si, ROAM_TRIGGER_SCAN_DONE, &ev);
                        break;
                }
@@ -304,7 +307,7 @@ usteer_roam_trigger_sm(struct sta_info *si)
                        break;
                }
 
-               if (find_better_candidate(si, &ev))
+               if (find_better_candidate(si, &ev, (1 << UEV_SELECT_REASON_SIGNAL)))
                        usteer_roam_set_state(si, ROAM_TRIGGER_WAIT_KICK, &ev);
 
                break;
@@ -454,7 +457,7 @@ usteer_local_node_kick(struct usteer_local_node *ln)
                if (is_more_kickable(kick1, si))
                        kick1 = si;
 
-               tmp = find_better_candidate(si, NULL);
+               tmp = find_better_candidate(si, NULL, 0);
                if (!tmp)
                        continue;