Date: Tue, 8 Feb 2011 11:24:29 +0300 From: Alexander Zagrebin <alex@zagrebin.ru> To: Bernhard Schmidt <bschmidt@freebsd.org> Cc: freebsd-net@freebsd.org, PseudoCylon <moonlightakkiy@yahoo.ca> Subject: Re: if_run in hostap mode: issue with stations in the power save mode Message-ID: <20110208082428.GA83490@gw.zagrebin.ru> In-Reply-To: <201102070911.02791.bschmidt@freebsd.org> References: <20110204060808.GA97298@gw.zagrebin.ru> <201102061132.41032.bschmidt@freebsd.org> <20110207061001.GB59910@gw.zagrebin.ru> <201102070911.02791.bschmidt@freebsd.org>
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Hi!
On 07.02.2011 09:11:02 +0100, Bernhard Schmidt wrote:
> For example, if you call 'ifconfig wlan0 ssid <newssid>' the new ssid is
> passed over using a IOCTL. It would be interesting to know what function
> in net80211 are called regarding beacon updates and which of those call
> into the run driver. Ultimately it's about figuring out if special
> handling for such cases are required and if so, how to do it.
I've added a debug output on allocation, changing and deallocation of a
beacon into if_run.c and tried to change SSID while the net.wlan.0.debug is -1.
Here is the log contents:
kernel: wlan0: ieee80211_init
kernel: wlan0: start running, 1 vaps running
kernel: wlan0: ieee80211_new_state_locked: RUN -> SCAN (nrunning 0 nscanning 0)
kernel: wlan0: ieee80211_newstate_cb: RUN -> INIT arg 0
kernel: wlan0: hostap_newstate: RUN -> INIT (0)
kernel: wlan0: node_reclaim: remove 0xffffff8003bd7000<00:14:d1:a8:66:1d> from station table, refcnt 1
kernel: wlan0: ieee80211_alloc_node 0xffffff8004eae000<00:14:d1:a8:66:1d> in station table
kernel: wlan0: [00:14:d1:a8:66:1d] ieee80211_alloc_node: inact_reload 2
kernel: wlan0: ieee80211_newstate_cb: INIT -> SCAN arg 0
kernel: wlan0: hostap_newstate: INIT -> SCAN (0)
kernel: wlan0: ieee80211_create_ibss: creating HOSTAP on channel 6
kernel: wlan0: ieee80211_alloc_node 0xffffff8003bd7000<00:14:d1:a8:66:1d> in station table
kernel:
kernel: wlan0: [00:14:d1:a8:66:1d] ieee80211_alloc_node: inact_reload 2
kernel: wlan0: set WME_AC_BE (chan) [acm 0 aifsn 3 logcwmin 4 logcwmax 6 txop 0]
kernel: wlan0: set WME_AC_BE (bss ) [acm 0 aifsn 3 logcwmin 4 logcwmax 10 txop 0]
kernel: wlan0: set WME_AC_BK (chan) [acm 0 aifsn 7 logcwmin 4 logcwmax 10 txop 0]
kernel: wlan0: set WME_AC_BK (bss ) [acm 0 aifsn 7 logcwmin 4 logcwmax 10 txop 0]
kernel: wlan0: set WME_AC_VI (chan) [acm 0 aifsn 1 logcwmin 3 logcwmax 4 txop 94]
kernel: wlan0: set WME_AC_VI (bss ) [acm 0 aifsn 2 logcwmin 3 logcwmax 4 txop 94]
kernel: wlan0: set WME_AC_VO (chan) [acm 0 aifsn 1 logcwmin 2 logcwmax 3 txop 47]
kernel: wlan0: set WME_AC_VO (bss ) [acm 0 aifsn 2 logcwmin 2 logcwmax 3 txop 47]
kernel: wlan0: ieee80211_wme_updateparams_locked: WME params updated, cap_info 0x6
kernel: wlan0: ieee80211_new_state_locked: SCAN -> RUN (nrunning 0 nscanning 0)
kernel: wlan0: ieee80211_newstate_cb: SCAN -> RUN arg -1
kernel: run0: run_update_beacon_cb: updating beacon
kernel: wlan0: ieee80211_beacon_update: traffic 0, enable aggressive mode
kernel: wlan0: update WME_AC_BE (chan+bss) [acm 0 aifsn 2 logcwmin 4 logcwmax 10 txop 0]
kernel: wlan0: update WME_AC_BE (chan+bss) logcwmin 3
kernel: wlan0: ieee80211_wme_updateparams_locked: WME params updated, cap_info 0x7
kernel: wlan0: hostap_newstate: SCAN -> RUN (-1)
kernel: wlan0: synchronized with 00:14:d1:a8:66:1d ssid "test" channel 6 start 0Mb
kernel: wlan0: [00:14:d1:a8:66:1d] ieee80211_node_authorize: inact_reload 20
As you can see, run_update_beacon_cb() is invoked, but at this time the
beacon is already allocated. As the beacon is allocated, run_update_beacon_cb()
invokes ieee80211_beacon_update(). As we know, the ieee80211_beacon_update()
doesn't update the SSID, so the SSID remains untouched.
Nevertheless the changing or hiding/unhiding a SSID seems to be working.
It is possible to explain: the station uses an active scan.
The ieee80211_send_proberesp()/ieee80211_alloc_proberesp() returns the frame,
containing an updated SSID, but AP continues to broadcast beacon with the
outdated data.
The possible solution is to deallocate a beacon on a state change.
I've decided to deallocate a beacon on 'to RUN' state transition.
The additional patch is attached.
I'll do an additional tests later today...
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Alexander Zagrebin
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Content-Type: text/x-patch; charset=us-ascii
Content-Disposition: attachment; filename="patch-if_run.c"
--- /sys/dev/usb/wlan/if_run.c.orig 2011-02-08 09:52:18.994743647 +0300
+++ /sys/dev/usb/wlan/if_run.c 2011-02-08 11:04:17.114484851 +0300
@@ -1793,6 +1793,12 @@ run_newstate(struct ieee80211vap *vap, e
sc->runbmap |= bid;
}
+ if (rvp->beacon_mbuf) {
+ m_freem(rvp->beacon_mbuf);
+ rvp->beacon_mbuf = NULL;
+ }
+
switch (vap->iv_opmode) {
case IEEE80211_M_HOSTAP:
case IEEE80211_M_MBSS:
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