path: root/src/drivers/driver_wext.c
diff options
authorDavid A Benjamin <davidben@MIT.EDU>2010-09-05 16:04:10 (GMT)
committerJouni Malinen <j@w1.fi>2010-10-04 05:25:00 (GMT)
commit32f4e7b124f918a49de493b6adb068d7054dae5a (patch)
tree16d65c3e7061f4f1777584d80ffef0c125b48f22 /src/drivers/driver_wext.c
parent8602b0f21325ed32642c90b6ecbef0721e34083c (diff)
wext: Fix scan result signal levels when driver reports in dBm
wpa_supplicant showed signal levels incorrectly with some drivers: Jun 6 16:29:36 rupert wpa_supplicant[18945]: Current BSS: 00:0d:97:11:40:d6 level=190 Jun 6 16:29:36 rupert wpa_supplicant[18945]: Selected BSS: 00:0d:97:11:50:09 level=192 Judging from output from other tools (iwlist) and the min_diff block at the end of wpa_supplicant_need_to_roam, it seems these values should actually be negative. Specifically, if one treats that number as a signed char instead of unsigned, everything matches up. To be honest, I've little to no understanding of wireless, but looking at the source code for wireless-tools (iw_print_stats in iwlib.c), it seems that the fields of the iw_quality struct need to be decoded differently depending on various flags. I guess src/drivers/driver_wext.c should have similar logic in wext_get_scan_qual. I wrote a patch that attempts to replicate some of that logic, although it may be more complicated than is necessary; I think some of the complexity is for backwards-compatibility, which might not be necessary depending on wpa_supplicant's dependencies? In any case, it is attached. Again, I don't know how any of this works, so it's likely the patch is a bit off. But I think at least the logic to determine min_diff in wpa_supplicant_need_to_roam would be more accurate if level were determined correctly.
Diffstat (limited to 'src/drivers/driver_wext.c')
1 files changed, 13 insertions, 2 deletions
diff --git a/src/drivers/driver_wext.c b/src/drivers/driver_wext.c
index d3629dd..f0de6aa 100644
--- a/src/drivers/driver_wext.c
+++ b/src/drivers/driver_wext.c
@@ -1117,7 +1117,8 @@ static void wext_get_scan_freq(struct iw_event *iwe,
-static void wext_get_scan_qual(struct iw_event *iwe,
+static void wext_get_scan_qual(struct wpa_driver_wext_data *drv,
+ struct iw_event *iwe,
struct wext_scan_data *res)
res->res.qual = iwe->u.qual.qual;
@@ -1131,6 +1132,14 @@ static void wext_get_scan_qual(struct iw_event *iwe,
res->res.flags |= WPA_SCAN_NOISE_INVALID;
if (iwe->u.qual.updated & IW_QUAL_DBM)
res->res.flags |= WPA_SCAN_LEVEL_DBM;
+ if ((iwe->u.qual.updated & IW_QUAL_DBM) ||
+ ((iwe->u.qual.level != 0) &&
+ (iwe->u.qual.level > drv->max_level))) {
+ if (iwe->u.qual.level >= 64)
+ res->res.level -= 0x100;
+ if (iwe->u.qual.noise >= 64)
+ res->res.noise -= 0x100;
+ }
@@ -1406,7 +1415,7 @@ struct wpa_scan_results * wpa_driver_wext_get_scan_results(void *priv)
wext_get_scan_freq(iwe, &data);
- wext_get_scan_qual(iwe, &data);
+ wext_get_scan_qual(drv, iwe, &data);
wext_get_scan_encode(iwe, &data);
@@ -1504,6 +1513,8 @@ static int wpa_driver_wext_get_range(void *priv)
"assuming WPA is not supported");
+ drv->max_level = range->max_qual.level;
return 0;