cfg80211: regulatory: allow getting DFS CAC time from userspace

Introduce DFS CAC time as a regd param, configured per REG_RULE and
set per channel in cfg80211. DFS CAC time is close connected with
regulatory database configuration. Instead of using hardcoded values,
get DFS CAC time form regulatory database. Pass DFS CAC time to user
mode (mainly for iw reg get, iw list, iw info). Allow setting DFS CAC
time via CRDA. Add support for internal regulatory database.

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
[rewrap commit log]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index ff72cab..1ba9d62 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2335,6 +2335,7 @@
  * @NL80211_FREQUENCY_ATTR_NO_160MHZ: any 160 MHz (but not 80+80) channel
  *	using this channel as the primary or any of the secondary channels
  *	isn't possible
+ * @NL80211_FREQUENCY_ATTR_DFS_CAC_TIME: DFS CAC time in milliseconds.
  * @NL80211_FREQUENCY_ATTR_MAX: highest frequency attribute number
  *	currently defined
  * @__NL80211_FREQUENCY_ATTR_AFTER_LAST: internal use
@@ -2353,6 +2354,7 @@
 	NL80211_FREQUENCY_ATTR_NO_HT40_PLUS,
 	NL80211_FREQUENCY_ATTR_NO_80MHZ,
 	NL80211_FREQUENCY_ATTR_NO_160MHZ,
+	NL80211_FREQUENCY_ATTR_DFS_CAC_TIME,
 
 	/* keep last */
 	__NL80211_FREQUENCY_ATTR_AFTER_LAST,
@@ -2449,6 +2451,8 @@
  * 	If you don't have one then don't send this.
  * @NL80211_ATTR_POWER_RULE_MAX_EIRP: the maximum allowed EIRP for
  * 	a given frequency range. The value is in mBm (100 * dBm).
+ * @NL80211_ATTR_DFS_CAC_TIME: DFS CAC time in milliseconds.
+ *	If not present or 0 default CAC time will be used.
  * @NL80211_REG_RULE_ATTR_MAX: highest regulatory rule attribute number
  *	currently defined
  * @__NL80211_REG_RULE_ATTR_AFTER_LAST: internal use
@@ -2464,6 +2468,8 @@
 	NL80211_ATTR_POWER_RULE_MAX_ANT_GAIN,
 	NL80211_ATTR_POWER_RULE_MAX_EIRP,
 
+	NL80211_ATTR_DFS_CAC_TIME,
+
 	/* keep last */
 	__NL80211_REG_RULE_ATTR_AFTER_LAST,
 	NL80211_REG_RULE_ATTR_MAX = __NL80211_REG_RULE_ATTR_AFTER_LAST - 1