cfg80211: return channel noise via survey API

This patch implements the NL80211_CMD_GET_SURVEY command and an get_survey()
ops that a driver can implement. The goal of this command is to allow a
drivers to report channel survey data (e.g. channel noise, channel
occupation).

For now, only the mechanism to report back channel noise has been
implemented.

In future, there will either be a survey-trigger command --- or the existing
scan-trigger command will be enhanced. This will allow user-space to
request survey for arbitrary channels.

Note: any driver that cannot report channel noise should not report
any value at all, e.g. made-up -92 dBm.

Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index d2f276de9abe..45db17f81aa3 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -160,6 +160,11 @@
  * @NL80211_CMD_SCAN_ABORTED: scan was aborted, for unspecified reasons,
  *      partial scan results may be available
  *
+ * @NL80211_CMD_GET_SURVEY: get survey resuls, e.g. channel occupation
+ *      or noise level
+ * @NL80211_CMD_NEW_SURVEY_RESULTS: survey data notification (as a reply to
+ *      NL80211_CMD_GET_SURVEY and on the "scan" multicast group)
+ *
  * @NL80211_CMD_REG_CHANGE: indicates to userspace the regulatory domain
  *      has been changed and provides details of the request information
  *      that caused the change such as who initiated the regulatory request
@@ -341,6 +346,9 @@ enum nl80211_commands {
 
         NL80211_CMD_SET_WIPHY_NETNS,
 
+        NL80211_CMD_GET_SURVEY,
+        NL80211_CMD_NEW_SURVEY_RESULTS,
+
         /* add new commands above here */
 
         /* used to define NL80211_CMD_MAX below */
@@ -586,6 +594,10 @@ enum nl80211_commands {
  *
  * @NL80211_ATTR_4ADDR: Use 4-address frames on a virtual interface
  *
+ * @NL80211_ATTR_SURVEY_INFO: survey information about a channel, part of
+ *      the survey response for %NL80211_CMD_GET_SURVEY, nested attribute
+ *      containing info as possible, see &enum survey_info.
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -718,6 +730,8 @@ enum nl80211_attrs {
 
         NL80211_ATTR_4ADDR,
 
+        NL80211_ATTR_SURVEY_INFO,
+
         /* add attributes here, update the policy in nl80211.c */
 
         __NL80211_ATTR_AFTER_LAST,
@@ -1121,6 +1135,26 @@ enum nl80211_reg_rule_flags {
 };
 
 /**
+ * enum nl80211_survey_info - survey information
+ *
+ * These attribute types are used with %NL80211_ATTR_SURVEY_INFO
+ * when getting information about a survey.
+ *
+ * @__NL80211_SURVEY_INFO_INVALID: attribute number 0 is reserved
+ * @NL80211_SURVEY_INFO_FREQUENCY: center frequency of channel
+ * @NL80211_SURVEY_INFO_NOISE: noise level of channel (u8, dBm)
+ */
+enum nl80211_survey_info {
+        __NL80211_SURVEY_INFO_INVALID,
+        NL80211_SURVEY_INFO_FREQUENCY,
+        NL80211_SURVEY_INFO_NOISE,
+
+        /* keep last */
+        __NL80211_SURVEY_INFO_AFTER_LAST,
+        NL80211_SURVEY_INFO_MAX = __NL80211_SURVEY_INFO_AFTER_LAST - 1
+};
+
+/**
  * enum nl80211_mntr_flags - monitor configuration flags
  *
  * Monitor configuration flags.