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>

1 files changed, 52 insertions, 0 deletions

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 23bf0667540c..b2a8d8c84a57 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1797,6 +1797,12 @@ enum nl80211_commands {
  *	in a PBSS. Specified in %NL80211_CMD_CONNECT to request
  *	connecting to a PCP, and in %NL80211_CMD_START_AP to start
  *	a PCP instead of AP. Relevant for DMG networks only.
+ * @NL80211_ATTR_BSS_SELECT: nested attribute for driver supporting the
+ *	BSS selection feature. When used with %NL80211_CMD_GET_WIPHY it contains
+ *	attributes according &enum nl80211_bss_select_attr to indicate what
+ *	BSS selection behaviours are supported. When used with %NL80211_CMD_CONNECT
+ *	it contains the behaviour-specific attribute containing the parameters for
+ *	BSS selection to be done by driver and/or firmware.
  *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
@@ -2174,6 +2180,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_PBSS,
 
+	NL80211_ATTR_BSS_SELECT,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -4667,4 +4675,48 @@ 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 */