VAP Autocreation Upon modprobe ath_pci

Since 1/23/2006 (rev1407+) Madwifi will create a user station (a VAP {see Dictionary} of type "sta") by default. Prior versions of the MadWifi code did not do this, and many of the scripts and documents on this wiki reflect this prior method. Please keep this in mind as you read through the wiki: all post r1407 MadWifi code allows for the autocreation of a VAP, and all prior releases do not. This feature does Not Change the behavior of wlanconfig. However, any method or script that employed wlanconfig to construct multiple VAPs will not work as before, you should use the "autocreate=none" module option, as described below.

The default autocreation of the "sta" VAP (the ath0 station) makes the modprobe ath_pci instruction conform better with generally expected driver behavior, and many simple wireless support tools will now work with MadWifi when they previously could not.

One may create a VAP of any type by including the autocreate= argument in the modprobe ath_pci command. If no autocreate argument is given, then a VAP of type sta is automatically created.

Usage: modprobe ath_pci autocreate=[none|sta|ap|wds|adhoc|ahdemo|monitor]

  • none: No VAP is created
  • sta: Create a station (default)
  • ap: Create an Access Point
  • wds: Create an Access Point with WDS
  • adhoc: Create a VAP in adhoc mode
  • ahdemo: Create a VAP in ahdemo mode
  • monitor: Create a VAP in monitor mode

The autocreated interface will have a name of athX, where X is an integer value and usually will be 0, resulting in an interface named ath0. If you already have an interface with this name, the next free number will be chosen (for example ath1).

VAP Autocreation and Integrated Builds

If MadWifi has been compiled into the kernel image, then the rules described in Documentation/kernel-parameters.txt of the linux kernel archive must be adhered to:

Module parameters for modules that are built into the kernel image are specified on the kernel command line with the module name plus '.' plus parameter name, with '=' and value if appropriate.

For MadWifi, this translates to ath_pci.autocreate=[none|sta|ap|wds|adhoc|ahdemo|monitor]

Examples

To create an Access Point (master mode) by default: 

# modprobe ath_pci autocreate=ap

To disable VAP autocreation: 

# modprobe ath_pci autocreate=none

Please see the manpage for wlanconfig for details of the VAP types. Please see changeset 1407 for details of the ath_pci autocreate patch. See UserDocs for more examples and instruction on the use of MadWifi.