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Fix the scan handling for 11b->11g upgrades in a world where, well,

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it's not just 11b/11g.

The following was happening, and it's quite .. annoyingly grr-y.

* create vap, setup wpa_supplicant with no bgscanning, etc - there's
  no call to ieee80211_media_change, so vap->iv_des_mode is
  IEEE80211_MODE_AUTO;
* do ifconfig wlan0 scan - same thing, media_change doesn't get called,
  iv_des_mode stays as auto.
* But then, run wpa_cli and do 'scan' - it'll do a media change.
* if you're on 11ng, vap->iv_des_mode gets changed to IEEE80211_MODE_11NG
* Then makescanlist() is called.  There's a block of code that gets
  called if iv_des_mode != IEEE80211_MODE_AUTO, and it does this:

		if (vap->iv_des_mode != IEEE80211_MODE_11G ||
			    mode != IEEE80211_MODE_11B)
			continue;
		mode = IEEE80211_MODE_11G;	/* upgrade */

* .. now, iv_des_mode is not IEEE80211_MODE_11G, so it always runs
  'continue'
* .. and thus the scan list stays empty and no further channel
  scans occur. Ever.(1)

If you then disassociate and try associating to something, your
scan table has likely been purged / aged out and you'll never
see anything in the scan list.

(1) You need to do 'ifconfig wlan0 mode auto' or just destroy/re-create
    the VAP to get working wireless again.

Tested:

* iwn(4) - intel 5300 wifi; STA mode; using wpa_supplicant; bgscan
  enabled -and- wpa_supplicant scanning.

Thanks to:

* Everyone who kept poking me about this and wondering why the hell
  their wifi would eventually stop seeing scan lists.  Grr.
  I eventually snapped this evening and dug back into this code.
This commit is contained in:
Adrian Chadd 2014-12-18 05:17:18 +00:00
parent 4ff1fc3b17
commit 9c75c3d4ba
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=275875
1 changed files with 6 additions and 4 deletions
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10
sys/net80211/ieee80211_scan_sta.c
View File

@ -600,10 +600,12 @@ makescanlist(struct ieee80211_scan_state *ss, struct ieee80211vap *vap,
* so if the desired mode is 11g, then use
* the 11b channel list but upgrade the mode.
*/
if (vap->iv_des_mode != IEEE80211_MODE_11G ||
mode != IEEE80211_MODE_11B)
continue;
mode = IEEE80211_MODE_11G; /* upgrade */
if (vap->iv_des_mode == IEEE80211_MODE_11G) {
if (mode == IEEE80211_MODE_11G) /* Skip the G check */
continue;
else if (mode == IEEE80211_MODE_11B)
mode = IEEE80211_MODE_11G; /* upgrade */
}
}
} else {
/*