I have noticed that 'wpa_cli scan_results' always reported a signal
level of 0 for every bssid found during a scan. I found this a bit
odd (especially since ifconfig wlan0 list scan reported good signal
level data)
FreeBSD 8.0-RC1 r197417 amd64
Looking at the /usr/src/usr.sbin/wpa/wpa_supplicant/driver_freebsd.c
source, I found:
in wpa_driver_bsd_get_scan_results()
wsr->qual = sr->isr_rssi;
wsr->level = 0; /* XXX? */
This hardcodes the signal level to 0, and sets the signal quality to
the rssi value.
Looking around at the source, it seems that wpa_supplicant does not
ever use the quality variable, but instead looks at the level variable
in wpa_scan_result_compar ().
In an attempt to try to figure out what signal level vs signal quality
in wpa_supplicant context means, I found this:
http://lists.shmoo.com/pipermail/hostap/2006-December/014831.html, and
a feb-2009 change to scan_helpers.c (which drivers_freebsd.c seems to
be partially based upon)
http://hostap.epitest.fi/gitweb/gitweb.cgi?p=hostap.git;a=commitdiff;h=e1b525c3560614cc56c85b7d060f540900c4da34
So, it seems that some wpa_supplicant drivers use quality, and some
use level. Since quality(wsr->qual) does not seem to be used in
current wpa_supplicant in freebsd, should it instead look like ?:
(attached as an SVN diff with some debug as well)
wsr->ssid_len = sr->isr_ssid_len;
wsr->freq = sr->isr_freq;
wsr->noise = sr->isr_noise;
- wsr->qual = sr->isr_rssi;
- wsr->level = 0; /* XXX? */
+ wsr->qual = 0; /* XXX? */
+ wsr->level = sr->isr_rssi;
wsr->caps = sr->isr_capinfo;
wsr->maxrate = getmaxrate(sr->isr_rates, sr->isr_nrates);
vp = ((u_int8_t *)sr) + sr->isr_ie_off;
Should we just set qual to 0, or should we set qual to
rssi/rssi_max*100 (if we can determine rssi_max for a particular wlan
interface)
In any case, do you want me to file a PR on this ?
--Thanks!
---Dave H
Index: driver_freebsd.c
===================================================================
--- driver_freebsd.c (revision 197439)
+++ driver_freebsd.c (working copy)
@@ -641,6 +641,8 @@
/* use freq for channel preference */
/* all things being equal, use signal level */
+ wpa_printf(MSG_DEBUG, "%s: signal levels; %d:#1(wa) %d:#2(wb)",
+ __func__, wa->level, wb->level);
return wb->level - wa->level;
}
@@ -697,8 +699,8 @@
wsr->ssid_len = sr->isr_ssid_len;
wsr->freq = sr->isr_freq;
wsr->noise = sr->isr_noise;
- wsr->qual = sr->isr_rssi;
- wsr->level = 0; /* XXX? */
+ wsr->qual = 0; /* XXX? */
+ wsr->level = sr->isr_rssi;
wsr->caps = sr->isr_capinfo;
wsr->maxrate = getmaxrate(sr->isr_rates, sr->isr_nrates);
vp = ((u_int8_t *)sr) + sr->isr_ie_off;
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