CRDA(8)                                                       Linux                                                      CRDA(8)



NAME
       crda - send to the kernel a wireless regulatory domain for a given ISO / IEC 3166 alpha2

SYNOPSIS
       crda




Description
       crda is the Linux wireless central regulatory domain agent.  crda is intended to be used by udev scripts and should not
       be run manually unless debugging udev scripts.  crda is triggered to run by the kernel by sending a udev event upon a new
       regulatory domain change. Regulatory domain changes are triggered by the wireless kernel subsystem (upon initialization
       and on reception of country IEs), wireless drivers, or userspace (see iw ). Upon a regulatory domain change the kernel
       sends a udev change event for the regulatory platform. The kernel ignores regulatory domains sent to it if it does not
       expect them. The regulatory domain is read by crda from the regulatory.bin file.



RSA Digital Signature
       If built with openssl or gcrypt support crda will have embedded into it an RSA digital signature which will prevent it
       from reading corrupted or non-authored regulatory.bin files. Authorship is respected by the RSA public key packed into
       crda.  This specific crda package has been built with an RSA public key from John Linville (the Linux wireless kernel
       maintainer) and as such will only read regulatory.bin files signed by him. For further information see the regulatory.bin
       man page.



UDEV RULE
       A udev regulatory rule must be put in place in order to receive and parse udev events from the kernel in order to get
       udev to call crda with the passed ISO / IEC 3166 alpha2 country code.  An example udev rule which can be used (usually in
       /lib/udev/rules.d/85-regulatory.rules ):

       KERNEL=="regulatory*", ACTION=="change", SUBSYSTEM=="platform", RUN+="/sbin/crda"



Environment variable
       Set the COUNTRY environment variable with a specific ISO / IEC 3166 alpha2 country code and then run crda without argu-
       ments. This will send a regulatory domain for that alpha2 to the kernel.


SEE ALSO
       iw(8) regulatory.bin(5)

       http://wireless.kernel.org/en/developers/Regulatory/



crda                                                     23 January 2009                                                 CRDA(8)