cfg80211: Advertise extended capabilities per interface type to userspace

The driver extended capabilities may differ for different
interface types which the userspace needs to know (for
example the fine timing measurement initiator and responder
bits might differ for a station and AP). Add a new nl80211
attribute to provide extended capabilities per interface type
to userspace.

Signed-off-by: Vidyullatha Kanchanapally <vkanchan@qti.qualcomm.com>
Reviewed-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -3083,6 +3083,24 @@ struct wiphy_vendor_command {
 		      unsigned long *storage);
 };
 
+/**
+ * struct wiphy_iftype_ext_capab - extended capabilities per interface type
+ * @iftype: interface type
+ * @extended_capabilities: extended capabilities supported by the driver,
+ *	additional capabilities might be supported by userspace; these are the
+ *	802.11 extended capabilities ("Extended Capabilities element") and are
+ *	in the same format as in the information element. See IEEE Std
+ *	802.11-2012 8.4.2.29 for the defined fields.
+ * @extended_capabilities_mask: mask of the valid values
+ * @extended_capabilities_len: length of the extended capabilities
+ */
+struct wiphy_iftype_ext_capab {
+	enum nl80211_iftype iftype;
+	const u8 *extended_capabilities;
+	const u8 *extended_capabilities_mask;
+	u8 extended_capabilities_len;
+};
+
 /**
  * struct wiphy - wireless hardware description
  * @reg_notifier: the driver's regulatory notification callback,
@@ -3203,9 +3221,14 @@ struct wiphy_vendor_command {
  *	additional capabilities might be supported by userspace; these are
  *	the 802.11 extended capabilities ("Extended Capabilities element")
  *	and are in the same format as in the information element. See
- *	802.11-2012 8.4.2.29 for the defined fields.
+ *	802.11-2012 8.4.2.29 for the defined fields. These are the default
+ *	extended capabilities to be used if the capabilities are not specified
+ *	for a specific interface type in iftype_ext_capab.
  * @extended_capabilities_mask: mask of the valid values
  * @extended_capabilities_len: length of the extended capabilities
+ * @iftype_ext_capab: array of extended capabilities per interface type
+ * @num_iftype_ext_capab: number of interface types for which extended
+ *	capabilities are specified separately.
  * @coalesce: packet coalescing support information
  *
  * @vendor_commands: array of vendor commands supported by the hardware
@@ -3305,6 +3328,9 @@ struct wiphy {
 	const u8 *extended_capabilities, *extended_capabilities_mask;
 	u8 extended_capabilities_len;
 
+	const struct wiphy_iftype_ext_capab *iftype_ext_capab;
+	unsigned int num_iftype_ext_capab;
+
 	/* 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

include/uapi/linux/nl80211.h

@@ -1824,6 +1824,11 @@ enum nl80211_commands {
  *
  * @NL80211_ATTR_PAD: attribute used for padding for 64-bit alignment
  *
+ * @NL80211_ATTR_IFTYPE_EXT_CAPA: Nested attribute of the following attributes:
+ *	%NL80211_ATTR_IFTYPE, %NL80211_ATTR_EXT_CAPA,
+ *	%NL80211_ATTR_EXT_CAPA_MASK, to specify the extended capabilities per
+ *	interface type.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2206,6 +2211,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_PAD,
 
+	NL80211_ATTR_IFTYPE_EXT_CAPA,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,

net/wireless/core.c

@@ -750,6 +750,36 @@ int wiphy_register(struct wiphy *wiphy)
 		nl80211_send_reg_change_event(&request);
 	}
 
+	/* Check that nobody globally advertises any capabilities they do not
+	 * advertise on all possible interface types.
+	 */
+	if (wiphy->extended_capabilities_len &&
+	    wiphy->num_iftype_ext_capab &&
+	    wiphy->iftype_ext_capab) {
+		u8 supported_on_all, j;
+		const struct wiphy_iftype_ext_capab *capab;
+
+		capab = wiphy->iftype_ext_capab;
+		for (j = 0; j < wiphy->extended_capabilities_len; j++) {
+			if (capab[0].extended_capabilities_len > j)
+				supported_on_all =
+					capab[0].extended_capabilities[j];
+			else
+				supported_on_all = 0x00;
+			for (i = 1; i < wiphy->num_iftype_ext_capab; i++) {
+				if (j >= capab[i].extended_capabilities_len) {
+					supported_on_all = 0x00;
+					break;
+				}
+				supported_on_all &=
+					capab[i].extended_capabilities[j];
+			}
+			if (WARN_ON(wiphy->extended_capabilities[j] &
+				    ~supported_on_all))
+				break;
+		}
+	}
+
 	rdev->wiphy.registered = true;
 	rtnl_unlock();
 

net/wireless/nl80211.c

@@ -1264,7 +1264,7 @@ nl80211_send_mgmt_stypes(struct sk_buff *msg,
 struct nl80211_dump_wiphy_state {
 	s64 filter_wiphy;
 	long start;
-	long split_start, band_start, chan_start;
+	long split_start, band_start, chan_start, capa_start;
 	bool split;
 };
 
@@ -1761,6 +1761,47 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 			nla_nest_end(msg, nested);
 		}
 
+		state->split_start++;
+		break;
+	case 13:
+		if (rdev->wiphy.num_iftype_ext_capab &&
+		    rdev->wiphy.iftype_ext_capab) {
+			struct nlattr *nested_ext_capab, *nested;
+
+			nested = nla_nest_start(msg,
+						NL80211_ATTR_IFTYPE_EXT_CAPA);
+			if (!nested)
+				goto nla_put_failure;
+
+			for (i = state->capa_start;
+			     i < rdev->wiphy.num_iftype_ext_capab; i++) {
+				const struct wiphy_iftype_ext_capab *capab;
+
+				capab = &rdev->wiphy.iftype_ext_capab[i];
+
+				nested_ext_capab = nla_nest_start(msg, i);
+				if (!nested_ext_capab ||
+				    nla_put_u32(msg, NL80211_ATTR_IFTYPE,
+						capab->iftype) ||
+				    nla_put(msg, NL80211_ATTR_EXT_CAPA,
+					    capab->extended_capabilities_len,
+					    capab->extended_capabilities) ||
+				    nla_put(msg, NL80211_ATTR_EXT_CAPA_MASK,
+					    capab->extended_capabilities_len,
+					    capab->extended_capabilities_mask))
+					goto nla_put_failure;
+
+				nla_nest_end(msg, nested_ext_capab);
+				if (state->split)
+					break;
+			}
+			nla_nest_end(msg, nested);
+			if (i < rdev->wiphy.num_iftype_ext_capab) {
+				state->capa_start = i + 1;
+				break;
+			}
+		}
+
 		/* done */
 		state->split_start = 0;
 		break;