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>

4 files changed, 203 insertions, 2 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 4bc27049f4e5..8802d1bda382 100644
--- a/include/linux/nl80211.h
+++ b/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 */
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index dd1fd51638fc..09a0b268e5cf 100644
--- a/include/net/cfg80211.h
+++ b/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>
@@ -505,6 +509,83 @@ struct wiphy;
 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
  *
  * This struct is registered by fullmac card drivers and/or wireless stacks
@@ -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 */
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 341f3e595ebd..88fa3e03e3e9 100644
--- a/include/net/mac80211.h
+++ b/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
diff --git a/include/net/wireless.h b/include/net/wireless.h
index a42c1562d52b..1c6285eb1666 100644
--- a/include/net/wireless.h
+++ b/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