Merge "cfg80211: Define macro for report better BSS in sched scan"

4 files changed, 285 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 294344b3f0f0..e5930177c96a 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -70,6 +70,7 @@ struct wiphy;
 #define CFG80211_UPDATE_CONNECT_PARAMS 1
 #define CFG80211_BEACON_TX_RATE_CUSTOM_BACKPORT 1
 #define CFG80211_RAND_TA_FOR_PUBLIC_ACTION_FRAME 1
+#define CFG80211_REPORT_BETTER_BSS_IN_SCHED_SCAN 1
 
 /*
  * wireless hardware capability structures
@@ -1569,6 +1570,17 @@ struct cfg80211_sched_scan_plan {
 };
 
 /**
+ * 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 nl80211_band band;
+	s8 delta;
+};
+
+/**
  * struct cfg80211_sched_scan_request - scheduled scan request description
  *
  * @ssids: SSIDs to scan for (passed in the probe_reqs in active scans)
@@ -1603,6 +1615,16 @@ struct cfg80211_sched_scan_plan {
  *	cycle.  The driver may ignore this parameter and start
  *	immediately (or at any other time), if this feature is not
  *	supported.
+ * @relative_rssi_set: Indicates whether @relative_rssi is set or not.
+ * @relative_rssi: Relative RSSI threshold in dB to restrict scan result
+ *	reporting in connected state to cases where a matching BSS is determined
+ *	to have better or slightly worse RSSI than the current connected BSS.
+ *	The relative RSSI threshold values are ignored in disconnected state.
+ * @rssi_adjust: delta dB of RSSI preference to be given to the BSSs that belong
+ *	to the specified band while deciding whether a better BSS is reported
+ *	using @relative_rssi. If delta is a negative number, the BSSs that
+ *	belong to the specified band will be penalized by delta dB in relative
+ *	comparisions.
  */
 struct cfg80211_sched_scan_request {
 	struct cfg80211_ssid *ssids;
@@ -1622,6 +1644,10 @@ struct cfg80211_sched_scan_request {
 	u8 mac_addr[ETH_ALEN] __aligned(2);
 	u8 mac_addr_mask[ETH_ALEN] __aligned(2);
 
+	bool relative_rssi_set;
+	s8 relative_rssi;
+	struct cfg80211_bss_select_adjust rssi_adjust;
+
 	/* internal */
 	struct wiphy *wiphy;
 	struct net_device *dev;
@@ -1907,6 +1933,22 @@ struct cfg80211_ibss_params {
 };
 
 /**
+ * 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 +1985,7 @@ 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 +2010,7 @@ 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 +3328,9 @@ 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 +3458,8 @@ 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..0505b1f9872b 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1934,6 +1934,20 @@ enum nl80211_commands {
  * @NL80211_ATTR_BSSID: The BSSID of the AP. Note that %NL80211_ATTR_MAC is also
  *	used in various commands/events for specifying the BSSID.
  *
+ * @NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI: Relative RSSI threshold by which
+ *	other BSSs has to be better or slightly worse than the current
+ *	connected BSS so that they get reported to user space.
+ *	This will give an opportunity to userspace to consider connecting to
+ *	other matching BSSs which have better or slightly worse RSSI than
+ *	the current connected BSS by using an offloaded operation to avoid
+ *	unnecessary wakeups.
+ *
+ * @NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST: When present the RSSI level for BSSs in
+ *	the specified band is to be adjusted before doing
+ *	%NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI based comparision to figure out
+ *	better BSSs. The attribute value is a packed structure
+ *	value as specified by &struct nl80211_bss_select_rssi_adjust.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2340,6 +2354,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_BSSID,
 
+	NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI,
+	NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -3008,6 +3025,13 @@ enum nl80211_reg_rule_attr {
  *	how this API was implemented in the past. Also, due to the same problem,
  *	the only way to create a matchset with only an RSSI filter (with this
  *	attribute) is if there's only a single matchset with the RSSI attribute.
+ * @NL80211_SCHED_SCAN_MATCH_ATTR_RELATIVE_RSSI: Flag indicating whether
+ *	%NL80211_SCHED_SCAN_MATCH_ATTR_RSSI to be used as absolute RSSI or
+ *	relative to current bss's RSSI.
+ * @NL80211_SCHED_SCAN_MATCH_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_SCHED_SCAN_MATCH_ATTR_MAX: highest scheduled scan filter
  *	attribute number currently defined
  * @__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST: internal use
@@ -3017,6 +3041,8 @@ enum nl80211_sched_scan_match_attr {
 
 	NL80211_SCHED_SCAN_MATCH_ATTR_SSID,
 	NL80211_SCHED_SCAN_MATCH_ATTR_RSSI,
+	NL80211_SCHED_SCAN_MATCH_ATTR_RELATIVE_RSSI,
+	NL80211_SCHED_SCAN_MATCH_ATTR_RSSI_ADJUST,
 
 	/* keep last */
 	__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST,
@@ -4609,6 +4635,9 @@ enum nl80211_feature_flags {
  *	in @NL80211_CMD_FRAME while not associated.
  * @NL80211_EXT_FEATURE_MGMT_TX_RANDOM_TA_CONNECTED: This driver supports
  *	randomized TA in @NL80211_CMD_FRAME while associated.
+ * @NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI: The driver supports sched_scan
+ *	for reporting BSSs with better RSSI than the current connected BSS
+ *	(%NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI).
  *
  * @NUM_NL80211_EXT_FEATURES: number of extended features.
  * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
@@ -4626,6 +4655,7 @@ enum nl80211_ext_feature_index {
 	NL80211_EXT_FEATURE_FILS_STA,
 	NL80211_EXT_FEATURE_MGMT_TX_RANDOM_TA,
 	NL80211_EXT_FEATURE_MGMT_TX_RANDOM_TA_CONNECTED,
+	NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI,
 
 	/* add new features before the definition below */
 	NUM_NL80211_EXT_FEATURES,
@@ -4875,4 +4905,48 @@ 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 */
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 16043faba52c..14868e42f3ca 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -619,6 +619,13 @@ int wiphy_register(struct wiphy *wiphy)
 		     !rdev->ops->set_mac_acl)))
 		return -EINVAL;
 
+	/* assure only valid behaviours are flagged by driver
+	 * hence subtract 2 as bit 0 is invalid.
+	 */
+	if (WARN_ON(wiphy->bss_select_support &&
+		    (wiphy->bss_select_support & ~(BIT(__NL80211_BSS_SELECT_ATTR_AFTER_LAST) - 2))))
+		return -EINVAL;
+
 	if (wiphy->addresses)
 		memcpy(wiphy->perm_addr, wiphy->addresses[0].addr, ETH_ALEN);
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 2d71cafde513..5ec8e5cf8a8e 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -402,7 +402,12 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_SCHED_SCAN_DELAY] = { .type = NLA_U32 },
 	[NL80211_ATTR_REG_INDOOR] = { .type = NLA_FLAG },
 	[NL80211_ATTR_PBSS] = { .type = NLA_FLAG },
+	[NL80211_ATTR_BSS_SELECT] = { .type = NLA_NESTED },
 	[NL80211_ATTR_BSSID] = { .len = ETH_ALEN },
+	[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI] = { .type = NLA_S8 },
+	[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST] = {
+		.len = sizeof(struct nl80211_bss_select_rssi_adjust)
+	},
 };
 
 /* policy for the key attributes */
@@ -487,6 +492,15 @@ nl80211_plan_policy[NL80211_SCHED_SCAN_PLAN_MAX + 1] = {
 	[NL80211_SCHED_SCAN_PLAN_ITERATIONS] = { .type = NLA_U32 },
 };
 
+static const struct nla_policy
+nl80211_bss_select_policy[NL80211_BSS_SELECT_ATTR_MAX + 1] = {
+	[NL80211_BSS_SELECT_ATTR_RSSI] = { .type = NLA_FLAG },
+	[NL80211_BSS_SELECT_ATTR_BAND_PREF] = { .type = NLA_U32 },
+	[NL80211_BSS_SELECT_ATTR_RSSI_ADJUST] = {
+		.len = sizeof(struct nl80211_bss_select_rssi_adjust)
+	},
+};
+
 static int nl80211_prepare_wdev_dump(struct sk_buff *skb,
 				     struct netlink_callback *cb,
 				     struct cfg80211_registered_device **rdev,
@@ -1778,6 +1792,25 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 			}
 		}
 
+		if (rdev->wiphy.bss_select_support) {
+			struct nlattr *nested;
+			u32 bss_select_support = rdev->wiphy.bss_select_support;
+
+			nested = nla_nest_start(msg, NL80211_ATTR_BSS_SELECT);
+			if (!nested)
+				goto nla_put_failure;
+
+			i = 0;
+			while (bss_select_support) {
+				if ((bss_select_support & 1) &&
+				    nla_put_flag(msg, i))
+					goto nla_put_failure;
+				i++;
+				bss_select_support >>= 1;
+			}
+			nla_nest_end(msg, nested);
+		}
+
 		/* done */
 		state->split_start = 0;
 		break;
@@ -6087,6 +6120,73 @@ static int validate_scan_freqs(struct nlattr *freqs)
 	return n_channels;
 }
 
+static bool is_band_valid(struct wiphy *wiphy, enum ieee80211_band b)
+{
+	return b < IEEE80211_NUM_BANDS && wiphy->bands[b];
+}
+
+static int parse_bss_select(struct nlattr *nla, struct wiphy *wiphy,
+			    struct cfg80211_bss_selection *bss_select)
+{
+	struct nlattr *attr[NL80211_BSS_SELECT_ATTR_MAX + 1];
+	struct nlattr *nest;
+	int err;
+	bool found = false;
+	int i;
+
+	/* only process one nested attribute */
+	nest = nla_data(nla);
+	if (!nla_ok(nest, nla_len(nest)))
+		return -EINVAL;
+
+	err = nla_parse(attr, NL80211_BSS_SELECT_ATTR_MAX, nla_data(nest),
+			nla_len(nest), nl80211_bss_select_policy);
+	if (err)
+		return err;
+
+	/* only one attribute may be given */
+	for (i = 0; i <= NL80211_BSS_SELECT_ATTR_MAX; i++) {
+		if (attr[i]) {
+			if (found)
+				return -EINVAL;
+			found = true;
+		}
+	}
+
+	bss_select->behaviour = __NL80211_BSS_SELECT_ATTR_INVALID;
+
+	if (attr[NL80211_BSS_SELECT_ATTR_RSSI])
+		bss_select->behaviour = NL80211_BSS_SELECT_ATTR_RSSI;
+
+	if (attr[NL80211_BSS_SELECT_ATTR_BAND_PREF]) {
+		bss_select->behaviour = NL80211_BSS_SELECT_ATTR_BAND_PREF;
+		bss_select->param.band_pref =
+			nla_get_u32(attr[NL80211_BSS_SELECT_ATTR_BAND_PREF]);
+		if (!is_band_valid(wiphy, bss_select->param.band_pref))
+			return -EINVAL;
+	}
+
+	if (attr[NL80211_BSS_SELECT_ATTR_RSSI_ADJUST]) {
+		struct nl80211_bss_select_rssi_adjust *adj_param;
+
+		adj_param = nla_data(attr[NL80211_BSS_SELECT_ATTR_RSSI_ADJUST]);
+		bss_select->behaviour = NL80211_BSS_SELECT_ATTR_RSSI_ADJUST;
+		bss_select->param.adjust.band = adj_param->band;
+		bss_select->param.adjust.delta = adj_param->delta;
+		if (!is_band_valid(wiphy, bss_select->param.adjust.band))
+			return -EINVAL;
+	}
+
+	/* user-space did not provide behaviour attribute */
+	if (bss_select->behaviour == __NL80211_BSS_SELECT_ATTR_INVALID)
+		return -EINVAL;
+
+	if (!(wiphy->bss_select_support & BIT(bss_select->behaviour)))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int nl80211_parse_random_mac(struct nlattr **attrs,
 				    u8 *mac_addr, u8 *mac_addr_mask)
 {
@@ -6557,6 +6657,12 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 	if (!n_plans || n_plans > wiphy->max_sched_scan_plans)
 		return ERR_PTR(-EINVAL);
 
+	if (!wiphy_ext_feature_isset(
+		    wiphy, NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI) &&
+	    (attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI] ||
+	     attrs[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST]))
+		return ERR_PTR(-EINVAL);
+
 	request = kzalloc(sizeof(*request)
 			+ sizeof(*request->ssids) * n_ssids
 			+ sizeof(*request->match_sets) * n_match_sets
@@ -6762,6 +6868,26 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 		request->delay =
 			nla_get_u32(attrs[NL80211_ATTR_SCHED_SCAN_DELAY]);
 
+	if (attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI]) {
+		request->relative_rssi = nla_get_s8(
+			attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI]);
+		request->relative_rssi_set = true;
+	}
+
+	if (request->relative_rssi_set &&
+	    attrs[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST]) {
+		struct nl80211_bss_select_rssi_adjust *rssi_adjust;
+
+		rssi_adjust = nla_data(
+			attrs[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST]);
+		request->rssi_adjust.band = rssi_adjust->band;
+		request->rssi_adjust.delta = rssi_adjust->delta;
+		if (!is_band_valid(wiphy, request->rssi_adjust.band)) {
+			err = -EINVAL;
+			goto out_free;
+		}
+	}
+
 	err = nl80211_parse_sched_scan_plans(wiphy, n_plans, request, attrs);
 	if (err)
 		goto out_free;
@@ -8349,6 +8475,21 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
 		return -EOPNOTSUPP;
 	}
 
+	if (info->attrs[NL80211_ATTR_BSS_SELECT]) {
+		/* bss selection makes no sense if bssid is set */
+		if (connect.bssid) {
+			kzfree(connkeys);
+			return -EINVAL;
+		}
+
+		err = parse_bss_select(info->attrs[NL80211_ATTR_BSS_SELECT],
+				       wiphy, &connect.bss_select);
+		if (err) {
+			kzfree(connkeys);
+			return err;
+		}
+	}
+
 	wdev_lock(dev->ieee80211_ptr);
 	err = cfg80211_connect(rdev, dev, &connect, connkeys, NULL);
 	wdev_unlock(dev->ieee80211_ptr);
@@ -9245,6 +9386,20 @@ static int nl80211_send_wowlan_nd(struct sk_buff *msg,
 	if (nla_put_u32(msg, NL80211_ATTR_SCHED_SCAN_DELAY, req->delay))
 		return -ENOBUFS;
 
+	if (req->relative_rssi_set) {
+		struct nl80211_bss_select_rssi_adjust rssi_adjust;
+
+		if (nla_put_s8(msg, NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI,
+			       req->relative_rssi))
+			return -ENOBUFS;
+
+		rssi_adjust.band = req->rssi_adjust.band;
+		rssi_adjust.delta = req->rssi_adjust.delta;
+		if (nla_put(msg, NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST,
+			    sizeof(rssi_adjust), &rssi_adjust))
+			return -ENOBUFS;
+	}
+
 	freqs = nla_nest_start(msg, NL80211_ATTR_SCAN_FREQUENCIES);
 	if (!freqs)
 		return -ENOBUFS;