cfg80211/nl80211: add support for scheduled scans

Implement new functionality for scheduled scan offload.  With this feature we
can scan automatically at certain intervals.

The idea is that the hardware can perform scan automatically and filter on
desired results without waking up the host unnecessarily.

Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
commands to the nl80211 interface.  When results are available they are
reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
informed when the scheduled scan has stopped with a
NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 82 insertions, 0 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index de96783954a..f8b5595ba4a 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -203,6 +203,26 @@
  * @NL80211_CMD_SCAN_ABORTED: scan was aborted, for unspecified reasons,
  *	partial scan results may be available
  *
+ * @NL80211_CMD_START_SCHED_SCAN: start a scheduled scan.  Like with normal
+ *	scans, if SSIDs (%NL80211_ATTR_SCAN_SSIDS) are passed, they are used
+ *	in the probe requests.  For broadcast, a broadcast SSID must be
+ *	passed (ie. an empty string).  If no SSID is passed, no probe
+ *	requests are sent and a passive scan is performed.
+ *	%NL80211_ATTR_SCAN_FREQUENCIES, if passed, define which channels
+ *	should be scanned; if not passed, all channels allowed for the
+ *	current regulatory domain are used.  Extra IEs can also be passed
+ *	from the userspace by using the %NL80211_ATTR_IE attribute.
+ * @NL80211_CMD_STOP_SCHED_SCAN: stop a scheduled scan
+ * @NL80211_CMD_SCHED_SCAN_RESULTS: indicates that there are scheduled scan
+ *	results available.
+ * @NL80211_CMD_SCHED_SCAN_STOPPED: indicates that the scheduled scan has
+ *	stopped.  The driver may issue this event at any time during a
+ *	scheduled scan.  One reason for stopping the scan is if the hardware
+ *	does not support starting an association or a normal scan while running
+ *	a scheduled scan.  This event is also sent when the
+ *	%NL80211_CMD_STOP_SCHED_SCAN command is received or when the interface
+ *	is brought down while a scheduled scan was running.
+ *
  * @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
@@ -545,6 +565,11 @@ enum nl80211_commands {
 	NL80211_CMD_GET_WOWLAN,
 	NL80211_CMD_SET_WOWLAN,
 
+	NL80211_CMD_START_SCHED_SCAN,
+	NL80211_CMD_STOP_SCHED_SCAN,
+	NL80211_CMD_SCHED_SCAN_RESULTS,
+	NL80211_CMD_SCHED_SCAN_STOPPED,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 4b0d035be64..e214c85b74d 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -824,6 +824,33 @@ struct cfg80211_scan_request {
 };
 
 /**
+ * struct cfg80211_sched_scan_request - scheduled scan request description
+ *
+ * @ssids: SSIDs to scan for (passed in the probe_reqs in active scans)
+ * @n_ssids: number of SSIDs
+ * @n_channels: total number of channels to scan
+ * @ie: optional information element(s) to add into Probe Request or %NULL
+ * @ie_len: length of ie in octets
+ * @wiphy: the wiphy this was for
+ * @dev: the interface
+ * @channels: channels to scan
+ */
+struct cfg80211_sched_scan_request {
+	struct cfg80211_ssid *ssids;
+	int n_ssids;
+	u32 n_channels;
+	const u8 *ie;
+	size_t ie_len;
+
+	/* internal */
+	struct wiphy *wiphy;
+	struct net_device *dev;
+
+	/* keep last */
+	struct ieee80211_channel *channels[0];
+};
+
+/**
  * enum cfg80211_signal_type - signal type
  *
  * @CFG80211_SIGNAL_TYPE_NONE: no signal strength information available
@@ -1292,6 +1319,10 @@ struct cfg80211_wowlan {
  * @set_power_mgmt: Configure WLAN power management. A timeout value of -1
  *	allows the driver to adjust the dynamic ps timeout value.
  * @set_cqm_rssi_config: Configure connection quality monitor RSSI threshold.
+ * @sched_scan_start: Tell the driver to start a scheduled scan.
+ * @sched_scan_stop: Tell the driver to stop an ongoing scheduled
+ *	scan.  The driver_initiated flag specifies whether the driver
+ *	itself has informed that the scan has stopped.
  *
  * @mgmt_frame_register: Notify driver that a management frame type was
  *	registered. Note that this callback may not sleep, and cannot run
@@ -1478,6 +1509,12 @@ struct cfg80211_ops {
 	int	(*set_ringparam)(struct wiphy *wiphy, u32 tx, u32 rx);
 	void	(*get_ringparam)(struct wiphy *wiphy,
 				 u32 *tx, u32 *tx_max, u32 *rx, u32 *rx_max);
+
+	int	(*sched_scan_start)(struct wiphy *wiphy,
+				struct net_device *dev,
+				struct cfg80211_sched_scan_request *request);
+	int	(*sched_scan_stop)(struct wiphy *wiphy, struct net_device *dev,
+				   bool driver_initiated);
 };
 
 /*
@@ -1522,6 +1559,7 @@ struct cfg80211_ops {
  * @WIPHY_FLAG_IBSS_RSN: The device supports IBSS RSN.
  * @WIPHY_FLAG_MESH_AUTH: The device supports mesh authentication by routing
  *	auth frames to userspace. See @NL80211_MESH_SETUP_USERSPACE_AUTH.
+ * @WIPHY_FLAG_SCHED_SCAN: The device supports scheduled scans.
  */
 enum wiphy_flags {
 	WIPHY_FLAG_CUSTOM_REGULATORY		= BIT(0),
@@ -1534,6 +1572,7 @@ enum wiphy_flags {
 	WIPHY_FLAG_CONTROL_PORT_PROTOCOL	= BIT(7),
 	WIPHY_FLAG_IBSS_RSN			= BIT(8),
 	WIPHY_FLAG_MESH_AUTH			= BIT(10),
+	WIPHY_FLAG_SUPPORTS_SCHED_SCAN		= BIT(11),
 };
 
 struct mac_address {
@@ -2355,6 +2394,24 @@ int cfg80211_wext_siwpmksa(struct net_device *dev,
 void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted);
 
 /**
+ * cfg80211_sched_scan_results - notify that new scan results are available
+ *
+ * @wiphy: the wiphy which got scheduled scan results
+ */
+void cfg80211_sched_scan_results(struct wiphy *wiphy);
+
+/**
+ * cfg80211_sched_scan_stopped - notify that the scheduled scan has stopped
+ *
+ * @wiphy: the wiphy on which the scheduled scan stopped
+ *
+ * The driver can call this function to inform cfg80211 that the
+ * scheduled scan had to be stopped, for whatever reason.  The driver
+ * is then called back via the sched_scan_stop operation when done.
+ */
+void cfg80211_sched_scan_stopped(struct wiphy *wiphy);
+
+/**
  * cfg80211_inform_bss_frame - inform cfg80211 of a received BSS frame
  *
  * @wiphy: the wiphy reporting the BSS