[RFC 1/4] wifi: nl80211: allow drivers to support subset of NL80211_CMD_SET_BSS

The so-called fullmac devices rely on firmware functionality and/or API to
change BSS parameters. Today there are limited drivers supporting the
nl80211 primitive, but they only handle a subset of the bss parameters
passed if any. The mac80211 driver does handle all parameters and stores
their configured values.

Signed-off-by: Arend van Spriel <[email protected]>
---
 include/net/cfg80211.h       | 30 ++++++++++++++++++++++++++++++
 include/uapi/linux/nl80211.h |  4 ++++
 net/wireless/nl80211.c       | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index d1848dc8ec99..8f9338c1e976 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2326,6 +2326,30 @@ struct mpath_info {
 	int generation;
 };
 
+/**
+ * enum wiphy_bss_param_flags - bit positions for supported bss parameters.
+ *
+ * @WIPHY_BSS_PARAM_CTS_PROT: support changing CTS protection.
+ * @WIPHY_BSS_PARAM_SHORT_PREAMBLE: support changing short preamble usage.
+ * @WIPHY_BSS_PARAM_SHORT_SLOT_TIME: support changing short slot time usage.
+ * @WIPHY_BSS_PARAM_BASIC_RATES: support reconfiguring basic rates.
+ * @WIPHY_BSS_PARAM_AP_ISOLATE: support changing AP isolation.
+ * @WIPHY_BSS_PARAM_HT_OPMODE: support changing HT operating mode.
+ * @WIPHY_BSS_PARAM_P2P_CTWINDOW: support reconfiguring ctwindow.
+ * @WIPHY_BSS_PARAM_P2P_OPPPS: support changing P2P opportunistic power-save.
+ */
+enum wiphy_bss_param_flags {
+	WIPHY_BSS_PARAM_CTS_PROT = BIT(0),
+	WIPHY_BSS_PARAM_SHORT_PREAMBLE = BIT(1),
+	WIPHY_BSS_PARAM_SHORT_SLOT_TIME = BIT(2),
+	WIPHY_BSS_PARAM_BASIC_RATES = BIT(3),
+	WIPHY_BSS_PARAM_AP_ISOLATE = BIT(4),
+	WIPHY_BSS_PARAM_HT_OPMODE = BIT(5),
+	WIPHY_BSS_PARAM_P2P_CTWINDOW = BIT(6),
+	WIPHY_BSS_PARAM_P2P_OPPPS = BIT(7),
+	WIPHY_BSS_PARAM_MASK = (WIPHY_BSS_PARAM_P2P_OPPPS << 1) - 1
+};
+
 /**
  * struct bss_parameters - BSS parameters
  *
@@ -5638,6 +5662,11 @@ struct wiphy_radio {
  *	and probe responses.  This value should be set if the driver
  *	wishes to limit the number of csa counters. Default (0) means
  *	infinite.
+ * @bss_param_support: bitmask indicating which bss_parameters as defined in
+ *	&struct bss_parameters the driver can actually handle in the
+ *	.change_bss() callback. The bit positions are defined in &enum
+ *	wiphy_bss_param_flags.
+ *
  * @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.
@@ -5817,6 +5846,7 @@ struct wiphy {
 
 	u8 max_num_csa_counters;
 
+	u32 bss_param_support;
 	u32 bss_select_support;
 
 	u8 nan_supported_bands;
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index e9ccf43fe3c6..b81dffad2f8f 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2899,6 +2899,9 @@ enum nl80211_commands {
  *	APs Support". Drivers may set additional flags that they support
  *	in the kernel or device.
  *
+ * @NL80211_ATTR_BSS_PARAM: nested attribute used with %NL80211_CMD_GET_WIPHY
+ *	which indicates which BSS parameters can be modified.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3455,6 +3458,7 @@ enum nl80211_attrs {
 	NL80211_ATTR_EPCS,
 
 	NL80211_ATTR_ASSOC_MLD_EXT_CAPA_OPS,
+	NL80211_ATTR_BSS_PARAM,
 
 	/* add attributes here, update the policy in nl80211.c */
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index fd5f79266471..bf3cd044de13 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2996,6 +2996,40 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 			    rdev->wiphy.ext_features))
 			goto nla_put_failure;
 
+		if (rdev->wiphy.bss_param_support) {
+			struct nlattr *nested;
+			u32 parsup = rdev->wiphy.bss_param_support;
+
+			nested = nla_nest_start(msg, NL80211_ATTR_BSS_PARAM);
+			if (!nested)
+				goto nla_put_failure;
+
+			if ((parsup & WIPHY_BSS_PARAM_CTS_PROT) &&
+			    nla_put_flag(msg, NL80211_ATTR_BSS_CTS_PROT))
+				goto nla_put_failure;
+			if ((parsup & WIPHY_BSS_PARAM_SHORT_PREAMBLE) &&
+			    nla_put_flag(msg, NL80211_ATTR_BSS_SHORT_PREAMBLE))
+				goto nla_put_failure;
+			if ((parsup & WIPHY_BSS_PARAM_SHORT_SLOT_TIME) &&
+			    nla_put_flag(msg, NL80211_ATTR_BSS_SHORT_SLOT_TIME))
+				goto nla_put_failure;
+			if ((parsup & WIPHY_BSS_PARAM_BASIC_RATES) &&
+			    nla_put_flag(msg, NL80211_ATTR_BSS_BASIC_RATES))
+				goto nla_put_failure;
+			if ((parsup & WIPHY_BSS_PARAM_AP_ISOLATE) &&
+			    nla_put_flag(msg, NL80211_ATTR_AP_ISOLATE))
+				goto nla_put_failure;
+			if ((parsup & WIPHY_BSS_PARAM_HT_OPMODE) &&
+			    nla_put_flag(msg, NL80211_ATTR_BSS_HT_OPMODE))
+				goto nla_put_failure;
+			if ((parsup & WIPHY_BSS_PARAM_P2P_CTWINDOW) &&
+			    nla_put_flag(msg, NL80211_ATTR_P2P_CTWINDOW))
+				goto nla_put_failure;
+			if ((parsup & WIPHY_BSS_PARAM_P2P_OPPPS) &&
+			    nla_put_flag(msg, NL80211_ATTR_P2P_OPPPS))
+				goto nla_put_failure;
+			nla_nest_end(msg, nested);
+		}
 		if (rdev->wiphy.bss_select_support) {
 			struct nlattr *nested;
 			u32 bss_select_support = rdev->wiphy.bss_select_support;
-- 
2.43.5