1. 10 Apr, 2012 1 commit
  2. 13 Mar, 2012 1 commit
    • Paul Stewart's avatar
      mac80211: Don't let regulatory make us deaf · 3117bbdb
      Paul Stewart authored
      
      
      When regulatory information changes our HT behavior (e.g,
      when we get a country code from the AP we have just associated
      with), we should use this information to change the power with
      which we transmit, and what channels we transmit.  Sometimes
      the channel parameters we derive from regulatory information
      contradicts the parameters we used in association.  For example,
      we could have associated specifying HT40, but the regulatory
      rules we apply may forbid HT40 operation.
      
      In the situation above, we should reconfigure ourselves to
      transmit in HT20 only, however it makes no sense for us to
      disable receive in HT40, since if we associated with these
      parameters, the AP has every reason to expect we can and
      will receive packets this way.  The code in mac80211 does
      not have the capability of sending the appropriate action
      frames to signal a change in HT behaviour so the AP has
      no clue we can no longer receive frames encoded this way.
      In some broken AP implementations, this can leave us
      effectively deaf if the AP never retries in lower HT rates.
      
      This change breaks up the channel_type parameter in the
      ieee80211_enable_ht function into a separate receive and
      transmit part.  It honors the channel flags set by regulatory
      in order to configure the rate control algorithm, but uses
      the capability flags to configure the channel on the radio,
      since these were used in association to set the AP's transmit
      rate.
      Signed-off-by: default avatarPaul Stewart <pstew@chromium.org>
      Cc: Sam Leffler <sleffler@chromium.org>
      Cc: Johannes Berg <johannes@sipsolutions.net>
      Reviewed-by: default avatarLuis R Rodriguez <mcgrof@frijolero.org>
      Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
      3117bbdb
  3. 24 Jan, 2012 1 commit
  4. 14 Mar, 2011 1 commit
  5. 16 Sep, 2010 1 commit
  6. 28 May, 2010 1 commit
  7. 07 May, 2010 2 commits
    • Johannes Berg's avatar
      mac80211: improve HT channel handling · 0aaffa9b
      Johannes Berg authored
      
      
      Currently, when one interface switches HT mode,
      all others will follow along. This is clearly
      undesirable, since the new one might switch to
      no-HT while another one is operating in HT.
      
      Address this issue by keeping track of the HT
      mode per interface, and allowing only changes
      that are compatible, i.e. switching into HT40+
      is not possible when another interface is in
      HT40-, in that case the second one needs to
      fall back to HT20.
      
      Also, to allow drivers to know what's going on,
      store the per-interface HT mode (channel type)
      in the virtual interface's bss_conf.
      Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
      Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
      0aaffa9b
    • Johannes Berg's avatar
      cfg80211/mac80211: better channel handling · f444de05
      Johannes Berg authored
      
      
      Currently (all tested with hwsim) you can do stupid
      things like setting up an AP on a certain channel,
      then adding another virtual interface and making
      that associate on another channel -- this will make
      the beaconing to move channel but obviously without
      the necessary IEs data update.
      
      In order to improve this situation, first make the
      configuration APIs (cfg80211 and nl80211) aware of
      multi-channel operation -- we'll eventually need
      that in the future anyway. There's one userland API
      change and one API addition. The API change is that
      now SET_WIPHY must be called with virtual interface
      index rather than only wiphy index in order to take
      effect for that interface -- luckily all current
      users (hostapd) do that. For monitor interfaces, the
      old setting is preserved, but monitors are always
      slaved to other devices anyway so no guarantees.
      
      The second userland API change is the introduction
      of a per virtual interface SET_CHANNEL command, that
      hostapd should use going forward to make it easier
      to understand what's going on (it can automatically
      detect a kernel with this command).
      
      Other than mac80211, no existing cfg80211 drivers
      are affected by this change because they only allow
      a single virtual interface.
      
      mac80211, however, now needs to be aware that the
      channel settings are per interface now, and needs
      to disallow (for now) real multi-channel operation,
      which is another important part of this patch.
      
      One of the immediate benefits is that you can now
      start hostapd to operate on a hardware that already
      has a connection on another virtual interface, as
      long as you specify the same channel.
      
      Note that two things are left unhandled (this is an
      improvement -- not a complete fix):
      
       * different HT/no-HT modes
      
         currently you could start an HT AP and then
         connect to a non-HT network on the same channel
         which would configure the hardware for no HT;
         that can be fixed fairly easily
      
       * CSA
      
         An AP we're connected to on a virtual interface
         might indicate switching channels, and in that
         case we would follow it, regardless of how many
         other interfaces are operating; this requires
         more effort to fix but is pretty rare after all
      Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
      Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
      f444de05