nl80211: add feature for BSS selection support

Introducing a new feature that the driver can use to
indicate the driver/firmware supports configuration of BSS
selection criteria upon CONNECT command. This can be useful
when multiple BSS-es are found belonging to the same ESS,
ie. Infra-BSS with same SSID. The criteria can then be used to
offload selection of a preferred BSS.

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Lei Zhang <leizh@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
[move wiphy support check into parse_bss_select()]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Ashwini Patil<apati@codeaurora.org>
Git-commit: 38de03d2a28925b489c11546804e2f5418cc17a4
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next.git
CRs-Fixed: 1112378
Change-Id: I8fe69aab5215fe848c8deab123ecb1561a3b2402

2 files changed, 78 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 294344b3f0f0..2d28832fe787 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1907,6 +1907,33 @@ struct cfg80211_ibss_params {
 };
 
 /**
+ * struct cfg80211_bss_select_adjust - BSS selection with RSSI adjustment.
+ *
+ * @band: band of BSS which should match for RSSI level adjustment.
+ * @delta: value of RSSI level adjustment.
+ */
+struct cfg80211_bss_select_adjust {
+	enum ieee80211_band band;
+	s8 delta;
+};
+
+/**
+ * struct cfg80211_bss_selection - connection parameters for BSS selection.
+ *
+ * @behaviour: requested BSS selection behaviour.
+ * @param: parameters for requestion behaviour.
+ * @band_pref: preferred band for %NL80211_BSS_SELECT_ATTR_BAND_PREF.
+ * @adjust: parameters for %NL80211_BSS_SELECT_ATTR_RSSI_ADJUST.
+ */
+struct cfg80211_bss_selection {
+	enum nl80211_bss_select_attr behaviour;
+	union {
+		enum ieee80211_band band_pref;
+		struct cfg80211_bss_select_adjust adjust;
+	} param;
+};
+
+/**
  * struct cfg80211_connect_params - Connection parameters
  *
  * This structure provides information needed to complete IEEE 802.11
@@ -1943,6 +1970,7 @@ struct cfg80211_ibss_params {
  * @vht_capa_mask: The bits of vht_capa which are to be used.
  * @pbss: if set, connect to a PCP instead of AP. Valid for DMG
  *	networks.
+ * @bss_select: criteria to be used for BSS selection.
  * @prev_bssid: previous BSSID, if not %NULL use reassociate frame
  */
 struct cfg80211_connect_params {
@@ -1967,6 +1995,7 @@ struct cfg80211_connect_params {
 	struct ieee80211_vht_cap vht_capa;
 	struct ieee80211_vht_cap vht_capa_mask;
 	bool pbss;
+	struct cfg80211_bss_selection bss_select;
 	const u8 *prev_bssid;
 };
 
@@ -3284,6 +3313,9 @@ struct wiphy_iftype_ext_capab {
  *	low rssi when a frame is heard on different channel, then it should set
  *	this variable to the maximal offset for which it can compensate.
  *	This value should be set in MHz.
+ * @bss_select_support: bitmask indicating the BSS selection criteria supported
+ *	by the driver in the .connect() callback. The bit position maps to the
+ *	attribute indices defined in &enum nl80211_bss_select_attr.
  */
 struct wiphy {
 	/* assign these fields before you register the wiphy */
@@ -3411,6 +3443,8 @@ struct wiphy {
 	u8 max_num_csa_counters;
 	u8 max_adj_channel_rssi_comp;
 
+	u32 bss_select_support;
+
 	char priv[0] __aligned(NETDEV_ALIGN);
 };
 
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 335b331cbf4f..797182eaeb3f 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -4875,4 +4875,48 @@ enum nl80211_sched_scan_plan {
 		__NL80211_SCHED_SCAN_PLAN_AFTER_LAST - 1
 };
 
+/**
+ * struct nl80211_bss_select_rssi_adjust - RSSI adjustment parameters.
+ *
+ * @band: band of BSS that must match for RSSI value adjustment.
+ * @delta: value used to adjust the RSSI value of matching BSS.
+ */
+struct nl80211_bss_select_rssi_adjust {
+	__u8 band;
+	__s8 delta;
+} __attribute__((packed));
+
+/**
+ * enum nl80211_bss_select_attr - attributes for bss selection.
+ *
+ * @__NL80211_BSS_SELECT_ATTR_INVALID: reserved.
+ * @NL80211_BSS_SELECT_ATTR_RSSI: Flag indicating only RSSI-based BSS selection
+ *	is requested.
+ * @NL80211_BSS_SELECT_ATTR_BAND_PREF: attribute indicating BSS
+ *	selection should be done such that the specified band is preferred.
+ *	When there are multiple BSS-es in the preferred band, the driver
+ *	shall use RSSI-based BSS selection as a second step. The value of
+ *	this attribute is according to &enum nl80211_band (u32).
+ * @NL80211_BSS_SELECT_ATTR_RSSI_ADJUST: When present the RSSI level for
+ *	BSS-es in the specified band is to be adjusted before doing
+ *	RSSI-based BSS selection. The attribute value is a packed structure
+ *	value as specified by &struct nl80211_bss_select_rssi_adjust.
+ * @NL80211_BSS_SELECT_ATTR_MAX: highest bss select attribute number.
+ * @__NL80211_BSS_SELECT_ATTR_AFTER_LAST: internal use.
+ *
+ * One and only one of these attributes are found within %NL80211_ATTR_BSS_SELECT
+ * for %NL80211_CMD_CONNECT. It specifies the required BSS selection behaviour
+ * which the driver shall use.
+ */
+enum nl80211_bss_select_attr {
+	__NL80211_BSS_SELECT_ATTR_INVALID,
+	NL80211_BSS_SELECT_ATTR_RSSI,
+	NL80211_BSS_SELECT_ATTR_BAND_PREF,
+	NL80211_BSS_SELECT_ATTR_RSSI_ADJUST,
+
+	/* keep last */
+	__NL80211_BSS_SELECT_ATTR_AFTER_LAST,
+	NL80211_BSS_SELECT_ATTR_MAX = __NL80211_BSS_SELECT_ATTR_AFTER_LAST - 1
+};
+
 #endif /* __LINUX_NL80211_H */