1 Reply Latest reply on Mar 17, 2015 11:18 AM by roleohibachi

    Ubilinux access point hostapd/driver issue


      This is an issue mentioned as an "aside" in a few other threads by users dottedquad and bra, to deaf ears.


      I've got an Edison running ubilinux build 150309 (as of this writing, the most recent). I'm trying to configure wifi in access point mode, but experiencing what appear to be driver issues. However, numerous users have reported working APs, both on Yocto and Ubilinux. Where else might the three of us (and any others) look to find the problem?

      My suspicion is that nl80211 is either not trying, or is falling back on, the older, two-interface method that requires monitor mode. (https://wireless.wiki.kernel.org/en/users/documentation/hostapd) Perhaps I'm wrong, but the Edison wireless chipset driver doesn't support monitor mode. I cannot find any information about "forcing" one mode or the other.


      The usual steps first:


      rfkill is not blocking.


      /etc/default/hostapd includes only this uncommented line:



      /etc/hostapd/hostapd.conf is very near to the default values, and can be seen here hostapd.conf - Pastebin.com.


      /etc/network/interfaces has only:

      auto wlan0

      iface wlan0 inet static




      When trying to start hostapd (either on boot, with service, or by running # hostapd -ddK /etc/hostapd/hostapd.conf) , I receive the following output (full text for searchability):


      [....] Starting advanced IEEE 802.11 management: hostapdrmdir[ctrl_interface]: No such file or directory



      random: Trying to read entropy from /dev/random

      Configuration file: /etc/hostapd/hostapd.conf


      nl80211: interface wlan0 in phy phy2

      rfkill: initial event: idx=2 type=2 op=0 soft=0 hard=0

      rfkill: initial event: idx=5 type=2 op=0 soft=0 hard=0

      rfkill: initial event: idx=6 type=1 op=0 soft=0 hard=0

      rfkill: initial event: idx=7 type=1 op=0 soft=0 hard=0

      nl80211: Using driver-based off-channel TX

      nl80211: Use separate P2P group interface (driver advertised support)

      nl80211: TDLS supported

      nl80211: Add own interface ifindex 6

      nl80211: Set mode ifindex 6 iftype 3 (AP)

      nl80211: Create interface iftype 6 (MONITOR)

      Failed to create interface mon.wlan0: -19 (No such device)

      nl80211: Failed to set interface wlan0 into AP mode

      netlink: Operstate: linkmode=0, operstate=6

      nl80211: Set mode ifindex 6 iftype 2 (STATION)

      nl80211 driver initialization failed.

      rmdir[ctrl_interface]: No such file or directory


      dmesg produces only one line of new content:


      CFG80211-ERROR) wl_cfg80211_add_virtual_iface : device is not ready


      To me, this looks like a driver issue. iw list includes AP mode, but running # iwconfig wlan0 mode master generates:


      Error for wireless request "Set Mode" (8B06) :

          SET failed on device wlan0 ; Invalid argument.

        • 1. Re: Ubilinux access point hostapd/driver issue

          Resolved, thanks to @petn-randall on freenode #debian!

          The newest version of hostapd doesn't use the "old method" described by the documentation, but the version in the stock repositories that ship installed with Ubilinux does. Updating to the newest (testing) hostapd fixes it. Details follow.


          The problem:

          In the stock hostapd binary, receiving and sending management frames requires monitor mode interface. It attempts to configure one interface running in master mode for standard traffic and another one for authentication, keys management, etc. This method is still supported by nl80211 driver as a fallback, but is NOT supported by the Edison chipset and driver.

          Later, nl80211 implemented special commands for sending management frames (NL80211_CMD_FRAME) and subscribing to them (NL80211_CMD_REGISTER_FRAME). This allowed user space to handle wireless infrastructure using a single AP interface only. This is currently preferred method that can be used with all mac80211 drivers implementing AP mode. It solves our problem here, since it doesn't require a Monitor Mode interface (which we can't do). Newer versions of hostapd have already been patched to use this method - lucky us!

          The solution:

          First, add the testing repository to your list of repositories:

               # echo deb http://ftp.us.debian.org/debian testing main contrib non-free >> /etc/apt/sources.list

          Then, add an apt preference such that you don't update ALL your packages to testing versions. Unless you're into that kind of thing, I guess. As root, add these lines to /etc/apt/preferences (create the file if it doesn't exist).

               Package: *

               Pin: release a=testing

               Pin-Priority: 900

          Finally, update hostapd using the testing repo. Note which other packages will also be updated to testing versions as a result.

               # apt-get -t testing install hostapd

          It will ask a few questions during the install. Make sure to retain the customized /etc/init.d/hostapd provided by ubilinux. It is correctly configured for the edison. If you accidentally blow it away, here is an original: http://pastebin.com/KrvUBNDX

          It may restart a few services, like cron, while it runs. Once it's complete, double-check your configuration files (/etc/hostapd/hostapd.conf and /etc/network/interfaces and /etc/default/hostapd), and restart hostapd. Your access point should come up automagically!