cfg80211/nl80211: scanning (and mac80211 update to use it)

This patch adds basic scan capability to cfg80211/nl80211 and
changes mac80211 to use it. The BSS list that cfg80211 maintains
is made driver-accessible with a private area in each BSS struct,
but mac80211 doesn't yet use it. That's another large project.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn.c

@@ -2678,11 +2678,19 @@ static void iwl_bss_info_changed(struct ieee80211_hw *hw,
 
 }
 
-static int iwl_mac_hw_scan(struct ieee80211_hw *hw, u8 *ssid, size_t ssid_len)
+static int iwl_mac_hw_scan(struct ieee80211_hw *hw,
+			   struct cfg80211_scan_request *req)
 {
 	unsigned long flags;
 	struct iwl_priv *priv = hw->priv;
 	int ret;
+	u8 *ssid = NULL;
+	size_t ssid_len = 0;
+
+	if (req->n_ssids) {
+		ssid = req->ssids[0].ssid;
+		ssid_len = req->ssids[0].ssid_len;
+	}
 
 	IWL_DEBUG_MAC80211(priv, "enter\n");
 
@@ -2718,7 +2726,7 @@ static int iwl_mac_hw_scan(struct ieee80211_hw *hw, u8 *ssid, size_t ssid_len)
 
 	if (ssid_len) {
 		priv->one_direct_scan = 1;
-		priv->direct_ssid_len =  min_t(u8, ssid_len, IW_ESSID_MAX_SIZE);
+		priv->direct_ssid_len = ssid_len;
 		memcpy(priv->direct_ssid, ssid, priv->direct_ssid_len);
 	} else {
 		priv->one_direct_scan = 0;

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -1271,6 +1271,7 @@ int iwl_setup_mac(struct iwl_priv *priv)
 		BIT(NL80211_IFTYPE_ADHOC);
 
 	hw->wiphy->custom_regulatory = true;
+	hw->wiphy->max_scan_ssids = 1;
 
 	/* Default value; 4 EDCA QOS priorities */
 	hw->queues = 4;

drivers/net/wireless/iwlwifi/iwl-scan.c

@@ -860,7 +860,7 @@ void iwl_bg_scan_completed(struct work_struct *work)
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 		return;
 
-	ieee80211_scan_completed(priv->hw);
+	ieee80211_scan_completed(priv->hw, false);
 
 	/* Since setting the TXPOWER may have been deferred while
 	 * performing the scan, fire one off */

drivers/net/wireless/iwlwifi/iwl3945-base.c

@@ -4442,15 +4442,23 @@ static void iwl3945_bss_info_changed(struct ieee80211_hw *hw,
 
 }
 
-static int iwl3945_mac_hw_scan(struct ieee80211_hw *hw, u8 *ssid, size_t len)
+static int iwl3945_mac_hw_scan(struct ieee80211_hw *hw,
+			       struct cfg80211_scan_request *req)
 {
 	int rc = 0;
 	unsigned long flags;
 	struct iwl_priv *priv = hw->priv;
+	size_t len = 0;
+	u8 *ssid = NULL;
 	DECLARE_SSID_BUF(ssid_buf);
 
 	IWL_DEBUG_MAC80211(priv, "enter\n");
 
+	if (req->n_ssids) {
+		ssid = req->ssids[0].ssid;
+		len = req->ssids[0].ssid_len;
+	}
+
 	mutex_lock(&priv->mutex);
 	spin_lock_irqsave(&priv->lock, flags);
 
@@ -4478,9 +4486,8 @@ static int iwl3945_mac_hw_scan(struct ieee80211_hw *hw, u8 *ssid, size_t len)
 			       print_ssid(ssid_buf, ssid, len), len);
 
 		priv->one_direct_scan = 1;
-		priv->direct_ssid_len = (u8)
-		    min((u8) len, (u8) IW_ESSID_MAX_SIZE);
-		memcpy(priv->direct_ssid, ssid, priv->direct_ssid_len);
+		priv->direct_ssid_len = len;
+		memcpy(priv->direct_ssid, ssid, len);
 	} else
 		priv->one_direct_scan = 0;
 
@@ -5412,6 +5419,8 @@ static int iwl3945_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
 
 	hw->wiphy->custom_regulatory = true;
 
+	hw->wiphy->max_scan_ssids = 1;
+
 	/* 4 EDCA QOS priorities */
 	hw->queues = 4;
 

include/linux/nl80211.h

@@ -143,6 +143,13 @@
  *	added to all specified management frames generated by
  *	kernel/firmware/driver.
  *
+ * @NL80211_CMD_GET_SCAN: get scan results
+ * @NL80211_CMD_TRIGGER_SCAN: trigger a new scan with the given parameters
+ * @NL80211_CMD_NEW_SCAN_RESULTS: scan notification (as a reply to
+ *	NL80211_CMD_GET_SCAN and on the "scan" multicast group)
+ * @NL80211_CMD_SCAN_ABORTED: scan was aborted, for unspecified reasons,
+ *	partial scan results may be available
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -192,6 +199,11 @@ enum nl80211_commands {
 
 	NL80211_CMD_GET_REG,
 
+	NL80211_CMD_GET_SCAN,
+	NL80211_CMD_TRIGGER_SCAN,
+	NL80211_CMD_NEW_SCAN_RESULTS,
+	NL80211_CMD_SCAN_ABORTED,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -305,6 +317,18 @@ enum nl80211_commands {
  * @NL80211_ATTR_IE: Information element(s) data (used, e.g., with
  *	%NL80211_CMD_SET_MGMT_EXTRA_IE).
  *
+ * @NL80211_ATTR_MAX_NUM_SCAN_SSIDS: number of SSIDs you can scan with
+ *	a single scan request, a wiphy attribute.
+ *
+ * @NL80211_ATTR_SCAN_FREQUENCIES: nested attribute with frequencies (in MHz)
+ * @NL80211_ATTR_SCAN_SSIDS: nested attribute with SSIDs, leave out for passive
+ *	scanning and include a zero-length SSID (wildcard) for wildcard scan
+ * @NL80211_ATTR_SCAN_GENERATION: the scan generation increases whenever the
+ *	scan result list changes (BSS expired or added) so that applications
+ *	can verify that they got a single, consistent snapshot (when all dump
+ *	messages carried the same generation number)
+ * @NL80211_ATTR_BSS: scan result BSS
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -372,6 +396,13 @@ enum nl80211_attrs {
 	NL80211_ATTR_MGMT_SUBTYPE,
 	NL80211_ATTR_IE,
 
+	NL80211_ATTR_MAX_NUM_SCAN_SSIDS,
+
+	NL80211_ATTR_SCAN_FREQUENCIES,
+	NL80211_ATTR_SCAN_SSIDS,
+	NL80211_ATTR_SCAN_GENERATION,
+	NL80211_ATTR_BSS,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -841,4 +872,38 @@ enum nl80211_channel_type {
 	NL80211_CHAN_HT40MINUS,
 	NL80211_CHAN_HT40PLUS
 };
+
+/**
+ * enum nl80211_bss - netlink attributes for a BSS
+ *
+ * @__NL80211_BSS_INVALID: invalid
+ * @NL80211_BSS_FREQUENCY: frequency in MHz (u32)
+ * @NL80211_BSS_TSF: TSF of the received probe response/beacon (u64)
+ * @NL80211_BSS_BEACON_INTERVAL: beacon interval of the (I)BSS (u16)
+ * @NL80211_BSS_CAPABILITY: capability field (CPU order, u16)
+ * @NL80211_BSS_INFORMATION_ELEMENTS: binary attribute containing the
+ *	raw information elements from the probe response/beacon (bin)
+ * @NL80211_BSS_SIGNAL_MBM: signal strength of probe response/beacon
+ *	in mBm (100 * dBm) (s32)
+ * @NL80211_BSS_SIGNAL_UNSPEC: signal strength of the probe response/beacon
+ *	in unspecified units, scaled to 0..100 (u8)
+ * @__NL80211_BSS_AFTER_LAST: internal
+ * @NL80211_BSS_MAX: highest BSS attribute
+ */
+enum nl80211_bss {
+	__NL80211_BSS_INVALID,
+	NL80211_BSS_BSSID,
+	NL80211_BSS_FREQUENCY,
+	NL80211_BSS_TSF,
+	NL80211_BSS_BEACON_INTERVAL,
+	NL80211_BSS_CAPABILITY,
+	NL80211_BSS_INFORMATION_ELEMENTS,
+	NL80211_BSS_SIGNAL_MBM,
+	NL80211_BSS_SIGNAL_UNSPEC,
+
+	/* keep last */
+	__NL80211_BSS_AFTER_LAST,
+	NL80211_BSS_MAX = __NL80211_BSS_AFTER_LAST - 1
+};
+
 #endif /* __LINUX_NL80211_H */

include/net/cfg80211.h

@@ -4,6 +4,10 @@
 #include <linux/netlink.h>
 #include <linux/skbuff.h>
 #include <linux/nl80211.h>
+#include <linux/if_ether.h>
+#include <linux/ieee80211.h>
+#include <linux/wireless.h>
+#include <net/iw_handler.h>
 #include <net/genetlink.h>
 /* remove once we remove the wext stuff */
 #include <net/iw_handler.h>
@@ -504,6 +508,83 @@ struct wiphy;
 /* from net/ieee80211.h */
 struct ieee80211_channel;
 
+/**
+ * struct cfg80211_ssid - SSID description
+ * @ssid: the SSID
+ * @ssid_len: length of the ssid
+ */
+struct cfg80211_ssid {
+	u8 ssid[IEEE80211_MAX_SSID_LEN];
+	u8 ssid_len;
+};
+
+/**
+ * struct cfg80211_scan_request - scan request description
+ *
+ * @ssids: SSIDs to scan for (active scan only)
+ * @n_ssids: number of SSIDs
+ * @channels: channels to scan on.
+ * @n_channels: number of channels for each band
+ * @wiphy: the wiphy this was for
+ * @ifidx: the interface index
+ */
+struct cfg80211_scan_request {
+	struct cfg80211_ssid *ssids;
+	int n_ssids;
+	struct ieee80211_channel **channels;
+	u32 n_channels;
+
+	/* internal */
+	struct wiphy *wiphy;
+	int ifidx;
+};
+
+/**
+ * enum cfg80211_signal_type - signal type
+ *
+ * @CFG80211_SIGNAL_TYPE_NONE: no signal strength information available
+ * @CFG80211_SIGNAL_TYPE_MBM: signal strength in mBm (100*dBm)
+ * @CFG80211_SIGNAL_TYPE_UNSPEC: signal strength, increasing from 0 through 100
+ */
+enum cfg80211_signal_type {
+	CFG80211_SIGNAL_TYPE_NONE,
+	CFG80211_SIGNAL_TYPE_MBM,
+	CFG80211_SIGNAL_TYPE_UNSPEC,
+};
+
+/**
+ * struct cfg80211_bss - BSS description
+ *
+ * This structure describes a BSS (which may also be a mesh network)
+ * for use in scan results and similar.
+ *
+ * @bssid: BSSID of the BSS
+ * @tsf: timestamp of last received update
+ * @beacon_interval: the beacon interval as from the frame
+ * @capability: the capability field in host byte order
+ * @information_elements: the information elements (Note that there
+ *	is no guarantee that these are well-formed!)
+ * @len_information_elements: total length of the information elements
+ * @signal: signal strength value
+ * @signal_type: signal type
+ * @priv: private area for driver use, has at least wiphy->bss_priv_size bytes
+ */
+struct cfg80211_bss {
+	struct ieee80211_channel *channel;
+
+	u8 bssid[ETH_ALEN];
+	u64 tsf;
+	u16 beacon_interval;
+	u16 capability;
+	u8 *information_elements;
+	size_t len_information_elements;
+
+	s32 signal;
+	enum cfg80211_signal_type signal_type;
+
+	u8 priv[0] __attribute__((__aligned__(sizeof(void *))));
+};
+
 /**
  * struct cfg80211_ops - backend description for wireless configuration
  *
@@ -571,6 +652,11 @@ struct ieee80211_channel;
  * @set_channel: Set channel
  *
  * @set_mgmt_extra_ie: Set extra IE data for management frames
+ *
+ * @scan: Request to do a scan. If returning zero, the scan request is given
+ *	the driver, and will be valid until passed to cfg80211_scan_done().
+ *	For scan results, call cfg80211_inform_bss(); you can call this outside
+ *	the scan/scan_done bracket too.
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy);
@@ -648,6 +734,9 @@ struct cfg80211_ops {
 	int	(*set_mgmt_extra_ie)(struct wiphy *wiphy,
 				     struct net_device *dev,
 				     struct mgmt_extra_ie_params *params);
+
+	int	(*scan)(struct wiphy *wiphy, struct net_device *dev,
+			struct cfg80211_scan_request *request);
 };
 
 /* temporary wext handlers */
@@ -658,5 +747,47 @@ int cfg80211_wext_siwmode(struct net_device *dev, struct iw_request_info *info,
 			  u32 *mode, char *extra);
 int cfg80211_wext_giwmode(struct net_device *dev, struct iw_request_info *info,
 			  u32 *mode, char *extra);
+int cfg80211_wext_siwscan(struct net_device *dev,
+			  struct iw_request_info *info,
+			  union iwreq_data *wrqu, char *extra);
+int cfg80211_wext_giwscan(struct net_device *dev,
+			  struct iw_request_info *info,
+			  struct iw_point *data, char *extra);
+
+/**
+ * cfg80211_scan_done - notify that scan finished
+ *
+ * @request: the corresponding scan request
+ * @aborted: set to true if the scan was aborted for any reason,
+ *	userspace will be notified of that
+ */
+void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted);
+
+/**
+ * cfg80211_inform_bss - inform cfg80211 of a new BSS
+ *
+ * @wiphy: the wiphy reporting the BSS
+ * @bss: the found BSS
+ * @gfp: context flags
+ *
+ * This informs cfg80211 that BSS information was found and
+ * the BSS should be updated/added.
+ */
+struct cfg80211_bss*
+cfg80211_inform_bss_frame(struct wiphy *wiphy,
+			  struct ieee80211_channel *channel,
+			  struct ieee80211_mgmt *mgmt, size_t len,
+			  s32 signal, enum cfg80211_signal_type sigtype,
+			  gfp_t gfp);
+
+struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
+				      struct ieee80211_channel *channel,
+				      const u8 *bssid,
+				      const u8 *ssid, size_t ssid_len);
+struct cfg80211_bss *cfg80211_get_mesh(struct wiphy *wiphy,
+				       struct ieee80211_channel *channel,
+				       const u8 *meshid, size_t meshidlen,
+				       const u8 *meshcfg);
+void cfg80211_put_bss(struct cfg80211_bss *bss);
 
 #endif /* __NET_CFG80211_H */

include/net/mac80211.h

@@ -1406,7 +1406,8 @@ struct ieee80211_ops {
 	void (*update_tkip_key)(struct ieee80211_hw *hw,
 			struct ieee80211_key_conf *conf, const u8 *address,
 			u32 iv32, u16 *phase1key);
-	int (*hw_scan)(struct ieee80211_hw *hw, u8 *ssid, size_t len);
+	int (*hw_scan)(struct ieee80211_hw *hw,
+		       struct cfg80211_scan_request *req);
 	int (*get_stats)(struct ieee80211_hw *hw,
 			 struct ieee80211_low_level_stats *stats);
 	void (*get_tkip_seq)(struct ieee80211_hw *hw, u8 hw_key_idx,
@@ -1844,8 +1845,9 @@ void ieee80211_wake_queues(struct ieee80211_hw *hw);
  * mac80211 that the scan finished.
  *
  * @hw: the hardware that finished the scan
+ * @aborted: set to true if scan was aborted
  */
-void ieee80211_scan_completed(struct ieee80211_hw *hw);
+void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted);
 
 /**
  * ieee80211_iterate_active_interfaces - iterate active interfaces

include/net/wireless.h

@@ -213,6 +213,9 @@ struct wiphy {
 	bool custom_regulatory;
 	bool strict_regulatory;
 
+	int bss_priv_size;
+	u8 max_scan_ssids;
+
 	/* If multiple wiphys are registered and you're handed e.g.
 	 * a regular netdev with assigned ieee80211_ptr, you won't
 	 * know whether it points to a wiphy your driver has registered