Apply a symmetrical bias against moving away from higher bands

There is currently a bias towards moving to higher bands but not one
against moving away from them. Fix that.

Signed-off-by: Matthew Wang <matthewmwang@chromium.org>

diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index ee39a6570de5fcae840a80460f20cc34327a3759..e168cf38b02a645ba363ad58e2529030a92bc3dc 100644 (file)
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -2127,11 +2127,22 @@ wpas_get_est_throughput_from_bss_snr(const struct wpa_supplicant *wpa_s,
 }
 
 
+static int wpas_evaluate_band_score(int frequency)
+{
+       if (is_6ghz_freq(frequency))
+               return 2;
+       if (IS_5GHZ(frequency))
+               return 1;
+       return 0;
+}
+
+
 int wpa_supplicant_need_to_roam_within_ess(struct wpa_supplicant *wpa_s,
                                           struct wpa_bss *current_bss,
                                           struct wpa_bss *selected)
 {
        int min_diff, diff;
+       int cur_band_score, sel_band_score;
        int to_5ghz, to_6ghz;
        int cur_level, sel_level;
        unsigned int cur_est, sel_est;
@@ -2277,10 +2288,9 @@ int wpa_supplicant_need_to_roam_within_ess(struct wpa_supplicant *wpa_s,
        else if (sel_est > cur_est)
                min_diff--;
 
-       if (to_5ghz)
-               min_diff -= 2;
-       if (to_6ghz)
-               min_diff -= 2;
+       cur_band_score = wpas_evaluate_band_score(current_bss->freq);
+       sel_band_score = wpas_evaluate_band_score(selected->freq);
+       min_diff += (cur_band_score - sel_band_score) * 2;
        if (wpa_s->signal_threshold && cur_level <= wpa_s->signal_threshold &&
            sel_level > wpa_s->signal_threshold)
                min_diff -= 2;