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IEEE80211_REGDOMAIN(9)	 BSD Kernel Developer's	Manual	IEEE80211_REGDOMAIN(9)

     ieee80211_regdomain -- 802.11 regulatory support

     #include <net80211/ieee80211_var.h>
     #include <net80211/ieee80211_regdomain.h>

     ieee80211_init_channels(struct ieee80211com *,
	 const struct ieee80211_regdomain *, const uint8_t bands[]);

     ieee80211_sort_channels(struct ieee80211_channel *, int nchans);

     struct ieee80211_appie *
     ieee80211_alloc_countryie(struct ieee80211com *);

     The net80211 software layer provides a support framework for drivers that
     includes comprehensive regulatory support.	 net80211 provides mechanisms
     that enforce regulatory policy by privileged user applications.

     Drivers define a device's capabilities and	can intercept and control reg-
     ulatory changes requested through net80211.  The initial regulatory
     state, including the channel list,	must be	filled in by the driver	before
     calling ieee80211_ifattach().  The	channel	list should reflect the	set of
     channels the device is calibrated for use on.  This list may also be re-
     quested later through the ic_getradiocaps method in the ieee80211com
     structure.	 The ieee80211_init_channels() function	is provided as a rudi-
     mentary fallback for drivers that do not (or cannot) fill in a proper
     channel list.  Default regulatory state is	supplied such as the regula-
     tory SKU, ISO country code, location (e.g.	indoor,	outdoor), and a	set of
     frequency bands the device	is capable of operating	on.  net80211 popu-
     lates the channel table in	ic_channels with a default set of channels and
     capabilities.  Note this mechanism	should be used with care as any	mis-
     match between the channel list created and	the device's capabilities can
     result in runtime errors (e.g. a request to operate on a channel the de-
     vice does not support).  The SKU and country information are used for
     generating	802.11h	protocol elements and related operation	such as	for
     802.11d; mis-setup	by a driver is not fatal, only potentially confusing.

     Devices that do not have a	fixed/default regulatory state can set the
     regulatory	SKU to SKU_DEBUG and country code to CTRY_DEFAULT and leave
     proper setup to user applications.	 If default settings are known they
     can be installed and/or an	event can be dispatched	to user	space using
     ieee80211_notify_country()	so that	devd(8)	will do	the appropriate	setup
     work at system boot (or device insertion).

     The channel table is sorted to optimize lookups using the
     ieee80211_sort_channels() routine.	 This should be	done whenever the
     channel table contents are	modified.

     The ieee80211_alloc_countryie() function allocates	an information element
     as	specified by 802.11h.  Because this is expensive to generate it	is
     cached in ic_countryie and	generated only when regulatory state changes.
     Drivers that call ieee80211_alloc_countryie() directly should not help
     with this caching;	doing so may confuse the net80211 layer.

     Drivers can control regulatory change requests by overriding the
     ic_setregdomain method that checks	change requests.  While	drivers	can
     reject any	request	that does not meet its requirements it is recommended
     that one be lenient in what is accepted and, whenever possible, instead
     of	rejecting a request, alter it to be correct.  For example, if the
     transmit power cap	for a channel is too high the driver can either	reject
     the request or (better) reduce the	cap to be compliant.  Requests that
     include unacceptable channels should cause	the request to be rejected as
     otherwise a mismatch may be created between application state and the
     state managed by net80211.	 The exact rules by which to operate are still
     being codified.

     regdomain(5), ifconfig(8),	ieee80211(9)

BSD				August 4, 2009				   BSD


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