cfg80211/mac80211: fill qual.qual value/adjust max_qual.qual

Due to various bugs in the software stack we end up having
to fill qual.qual; level should be used, but wpa_supplicant
doesn't properly ignore qual.qual, NM should use qual.level
regardless of that because qual.qual is 0 but doesn't handle
IW_QUAL_DBM right now.

So fill qual.qual with the qual.level value clamped to
-110..-40 dBm or just the regular 'unspecified' signal level.
This requires a mac80211 change to properly announce the
max_qual.qual and avg_qual.qual values.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 28 insertions, 5 deletions

diff --git a/net/mac80211/wext.c b/net/mac80211/wext.c
index 8a76a979bc92..a8d4b6171916 100644
--- a/net/mac80211/wext.c
+++ b/net/mac80211/wext.c
@@ -200,10 +200,24 @@ static int ieee80211_ioctl_giwrange(struct net_device *dev,
         else
                 range->max_qual.noise = 0;
 
-        range->max_qual.qual = 100;
         range->max_qual.updated = ieee80211_get_wstats_flags(local);
 
-        range->avg_qual.qual = 50;
+        if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
+                /*
+                 * cfg80211 assumes -110 to -40 dBm and clamps to that range
+                 * for qual.qual, so tell userspace this is what we give it
+                 * but take into account that we have to start from 0.
+                 */
+                range->max_qual.qual = 70;
+                range->avg_qual.qual = 35;
+        } else {
+                /*
+                 * cfg80211 just uses the level value for qual too, and it
+                 * requires the level value to be 0 .. 100.
+                 */
+                range->max_qual.qual = 100;
+                range->avg_qual.qual = 50;
+        }
         /* not always true but better than nothing */
         range->avg_qual.level = range->max_qual.level / 2;
         range->avg_qual.noise = range->max_qual.noise / 2;
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 9fad1631d6cb..01c136d98c5b 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -614,7 +614,7 @@ ieee80211_bss(struct iw_request_info *info,
         struct iw_event iwe;
         u8 *buf, *cfg, *p;
         u8 *ie = bss->pub.information_elements;
-        int rem = bss->pub.len_information_elements, i;
+        int rem = bss->pub.len_information_elements, i, sig;
         bool ismesh = false;
 
         memset(&iwe, 0, sizeof(iwe));
@@ -643,14 +643,23 @@ ieee80211_bss(struct iw_request_info *info,
                 iwe.cmd = IWEVQUAL;
                 iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
                                      IW_QUAL_NOISE_INVALID |
-                                     IW_QUAL_QUAL_INVALID;
+                                     IW_QUAL_QUAL_UPDATED;
                 switch (bss->pub.signal_type) {
                 case CFG80211_SIGNAL_TYPE_MBM:
-                        iwe.u.qual.level = bss->pub.signal / 100;
+                        sig = bss->pub.signal / 100;
+                        iwe.u.qual.level = sig;
                         iwe.u.qual.updated |= IW_QUAL_DBM;
+                        if (sig < -110)         /* rather bad */
+                                sig = -110;
+                        else if (sig > -40)     /* perfect */
+                                sig = -40;
+                        /* will give a range of 0 .. 70 */
+                        iwe.u.qual.qual = sig + 110;
                         break;
                 case CFG80211_SIGNAL_TYPE_UNSPEC:
                         iwe.u.qual.level = bss->pub.signal;
+                        /* will give range 0 .. 100 */
+                        iwe.u.qual.qual = bss->pub.signal;
                         break;
                 default:
                         /* not reached */