How ACS behaves?

Thu Apr 27 19:01:43 PDT 2017

Updates:

I tried hostapd 2.6 release version (from .tar.gz), and it equally
doesn't perform ACS.

The expected ACS behaviour would be similar to this. My output cuts
out at "ctrl_iface not configured!", so just search for "ctrl_iface"
on this page to see all the fetching of survey data that I am missing
out on.
http://lists.infradead.org/pipermail/hostap/2016-July/035942.html

The second question should be easy to answer by anyone who has
observed ACS in action.

Cheers, Sam

On 26 April 2017 at 23:01, Sam Jaeschke <sam.jaeschke at gmail.com> wrote:
> Hi,
>
> I'm attempting to get ACS working to see how it behaves. Unfortunately
> I can't get it working.
>
> Release version:
> https://w1.fi/releases/hostapd-2.4.tar.gz
>
> Only differences in hostapd.conf:
> logger_stdout_level=0
> ap_max_inactivity=10
> ieee80211n=1
> channel=0
>
> Only differences in defconfig:
> CONFIG_LIBNL32=y
> CONFIG_IEEE80211N=y
> CONFIG_IEEE80211AC=y (should have turned that off - unused)
> CONFIG_ACS=y
>
> Using ath9k driver, with message on bootup:
> [    1.891393] ath9k 0000:01:00.0: enabling device (0140 -> 0142)
> [    2.018054] ieee80211 phy0: Atheros AR9300 Rev:3 mem=0xf0980000, irq=171
>
>
> I turned on ACS, expecting it to automatically select the best of the
> 1-11 channels on 2.4GHz in 802.11n mode.
>
>
> Starting up hostapd with -dd:
>
> Starting HOSTAP Daemon: 1493191720.536396: random: Trying to read
> entropy from /dev/random
> 1493191720.536549: Configuration file: /etc/hostapd.conf
> 1493191720.538374: ctrl_interface_group=0
> 1493191720.540665: rfkill: initial event: idx=0 type=1 op=0 soft=0 hard=0
> 1493191720.54115[    4.420957] IPv6: ADDRCONF(NETDEV_UP): wlan0: link
> is not ready
> 3: nl80211: TDLS supported
> 1493191720.541183: nl80211: TDLS external setup
> 1493191720.541209: nl80211: Supported cipher 00-0f-ac:1
> 1493191720.541230: nl80211: Supported cipher 00-0f-ac:5
> 1493191720.541248: nl80211: Supported cipher 00-0f-ac:2
> 1493191720.541264: nl80211: Supported cipher 00-0f-ac:4
> 1493191720.541280: nl80211: Supported cipher 00-0f-ac:10
> 1493191720.541296: nl80211: Supported cipher 00-0f-ac:8
> 1493191720.541311: nl80211: Supported cipher 00-0f-ac:9
> 1493191720.541326: nl80211: Supported cipher 00-0f-ac:6
> 1493191720.541342: nl80211: Supported cipher 00-0f-ac:13
> 1493191720.541357: nl80211: Supported cipher 00-0f-ac:11
> 1493191720.541373: nl80211: Supported cipher 00-0f-ac:12
> 1493191720.541550: nl80211: Using driver-based off-channel TX
> 1493191720.541619: nl80211: Use separate P2P group interface (driver
> advertised support)
> 1493191720.541639: nl80211: interface wlan0 in phy phy0
> 1493191720.541718: nl80211: Set mode ifindex 3 iftype 3 (AP)
> 1493191720.541788: nl80211: Setup AP(wlan0) - device_ap_sme=0 use_monitor=0
> 1493191720.541908: nl80211: Subscribe to mgmt frames with AP handle 0xad850
> 1493191720.541935: nl80211: Register frame type=0xb0
> (WLAN_FC_STYPE_AUTH) nl_handle=0xad850 match=
> 1493191720.542004: nl80211: Register frame type=0x0
> (WLAN_FC_STYPE_ASSOC_REQ) nl_handle=0xad850 match=
> 1493191720.542067: nl80211: Register frame type=0x20
> (WLAN_FC_STYPE_REASSOC_REQ) nl_handle=0xad850 match=
> 1493191720.542129: nl80211: Register frame type=0xa0
> (WLAN_FC_STYPE_DISASSOC) nl_handle=0xad850 match=
> 1493191720.542189: nl80211: Register frame type=0xc0
> (WLAN_FC_STYPE_DEAUTH) nl_handle=0xad850 match=
> 1493191720.542248: nl80211: Register frame type=0xd0
> (WLAN_FC_STYPE_ACTION) nl_handle=0xad850 match=
> 1493191720.542309: nl80211: Register frame type=0x40
> (WLAN_FC_STYPE_PROBE_REQ) nl_handle=0xad850 match=
> 1493191720.565668: nl80211: Add own interface ifindex 3
> 1493191720.565707: nl80211: if_indices[16]: 3
> 1493191720.565754: phy: phy0
> 1493191720.565776: BSS count 1, BSSID mask 00:00:00:00:00:00 (0 bits)
> 1493191720.566559: nl80211: Regulatory information - country=00
> 1493191720.566591: nl80211: 2402-2472 @ 40 MHz 20 mBm
> 1493191720.566616: nl80211: 2457-2482 @ 40 MHz 20 mBm (no IR)
> 1493191720.566639: nl80211: 2474-2494 @ 20 MHz 20 mBm (no OFDM) (no IR)
> 1493191720.566661: nl80211: 5170-5250 @ 160 MHz 20 mBm (no IR)
> 1493191720.566682: nl80211: 5250-5330 @ 160 MHz 20 mBm (DFS) (no IR)
> 1493191720.566704: nl80211: 5490-5730 @ 160 MHz 20 mBm (DFS) (no IR)
> 1493191720.566726: nl80211: 5735-5835 @ 80 MHz 20 mBm (no IR)
> 1493191720.566747: nl80211: 57240-63720 @ 2160 MHz 0 mBm
> 1493191720.566819: nl80211: Added 802.11b mode based on 802.11g information
> 1493191720.566840: Allowed channel: mode=1 chan=1 freq=2412 MHz
> max_tx_power=20 dBm
> 1493191720.566859: Allowed channel: mode=1 chan=2 freq=2417 MHz
> max_tx_power=20 dBm
> 1493191720.566877: Allowed channel: mode=1 chan=3 freq=2422 MHz
> max_tx_power=20 dBm
> 1493191720.566894: Allowed channel: mode=1 chan=4 freq=2427 MHz
> max_tx_power=20 dBm
> 1493191720.566910: Allowed channel: mode=1 chan=5 freq=2432 MHz
> max_tx_power=20 dBm
> 1493191720.566927: Allowed channel: mode=1 chan=6 freq=2437 MHz
> max_tx_power=20 dBm
> 1493191720.566944: Allowed channel: mode=1 chan=7 freq=2442 MHz
> max_tx_power=20 dBm
> 1493191720.566960: Allowed channel: mode=1 chan=8 freq=2447 MHz
> max_tx_power=20 dBm
> 1493191720.566977: Allowed channel: mode=1 chan=9 freq=2452 MHz
> max_tx_power=20 dBm
> 1493191720.566994: Allowed channel: mode=1 chan=10 freq=2457 MHz
> max_tx_power=20 dBm
> 1493191720.567010: Allowed channel: mode=1 chan=11 freq=2462 MHz
> max_tx_power=20 dBm
> 1493191720.567028: Allowed channel: mode=0 chan=1 freq=2412 MHz
> max_tx_power=20 dBm
> 1493191720.567045: Allowed channel: mode=0 chan=2 freq=2417 MHz
> max_tx_power=20 dBm
> 1493191720.567062: Allowed channel: mode=0 chan=3 freq=2422 MHz
> max_tx_power=20 dBm
> 1493191720.567078: Allowed channel: mode=0 chan=4 freq=2427 MHz
> max_tx_power=20 dBm
> 1493191720.567095: Allowed channel: mode=0 chan=5 freq=2432 MHz
> max_tx_power=20 dBm
> 1493191720.567112: Allowed channel: mode=0 chan=6 freq=2437 MHz
> max_tx_power=20 dBm
> 1493191720.567128: Allowed channel: mode=0 chan=7 freq=2442 MHz
> max_tx_power=20 dBm
> 1493191720.900419: Allowed channel: mode=0 chan=8 freq=2447 MHz
> max_tx_power=20 dBm
> 1493191720.900452: Allowed channel: mode=0 chan=9 freq=2452 MHz
> max_tx_power=20 dBm
> 1493191720.900471: Allowed channel: mode=0 chan=10 freq=2457 MHz
> max_tx_power=20 dBm
> 1493191720.900489: Allowed channel: mode=0 chan=11 freq=2462 MHz
> max_tx_power=20 dBm
> 1493191720.900508: ACS: Automatic channel selection started, this may take a bit
> 1493191720.900527: ACS: Scanning 1 / 5
> 1493191720.900552: wlan0: nl80211: scan request
> 1493191720.900584: nl80211: Scan frequency 2412 MHz
> 1493191720.900601: nl80211: Scan frequency 2417 MHz
> 1493191720.900616: nl80211: Scan frequency 2422 MHz
> 1493191720.900630: nl80211: Scan frequency 2427 MHz
> 1493191720.900644: nl80211: Scan frequency 2432 MHz
> 1493191720.900659: nl80211: Scan frequency 2437 MHz
> 1493191720.900673: nl80211: Scan frequency 2442 MHz
> 1493191720.900687: nl80211: Scan frequency 2447 MHz
> 1493191720.900701: nl80211: Scan frequency 2452 MHz
> 1493191720.900714: nl80211: Scan frequency 2457 MHz
> 1493191720.900728: nl80211: Scan frequency 2462 MHz
> 1493191720.912015: Scan requested (ret=0) - scan timeout 10 seconds
> 1493191720.912068: wlan0: interface state UNINITIALIZED->ACS
> 1493191720.912107: wlan0: ACS-STARTED
> 1493191720.912134: Interface initialization will be completed in a
> callback (ACS)
> 1493191720.912159: ctrl_iface not configured!
> hostapd.    <--------- this indicates the end of hostapd output
> [   10.971004] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
>
>
> So hostapd does work and provide an AP, but it's not on an automatic
> channel, and it's seems to always pick channel 1 regardless of how
> crowded it is with other devices.
> My understanding is that it should output some ACS scan info at the
> end, but it's not.
>
> Any ideas why ACS would not be working?
>
>
>
> I have been reading the ACS documentation (and the comments in the
> hostapd.conf), and haven't worked out how it does behave yet. Does it
> only scan once on startup? Or does it scan periodically while
> operation, and jump channels when it sees fit?
>
> Many thanks,
> Sam