nl80211: Add QCA vendor specific query of device/driver features

This commit introduces a QCA vendor command that allows interrogation of
the vendor-specific features supported by the device/driver. Currently
the only defined feature is the ability to offload key management.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/common/qca-vendor.h

@@ -53,15 +53,22 @@ enum qca_radiotap_vendor_ids {
  *
  * @QCA_NL80211_VENDOR_SUBCMD_KEY_MGMT_SET_KEY: Set key operation that can be
  *	used to configure PMK to the driver even when not connected. This can
- *	be used to request offloading of key management operations.
+ *	be used to request offloading of key management operations. Only used
+ *	if device supports QCA_WLAN_VENDOR_FEATURE_KEY_MGMT_OFFLOAD.
+ *
  * @QCA_NL80211_VENDOR_SUBCMD_KEY_MGMT_ROAM_AUTH: An extended version of
  *	NL80211_CMD_ROAM event with optional attributes including information
  *	from offloaded key management operation. Uses
- *	enum qca_wlan_vendor_attr_roam_auth attributes.
+ *	enum qca_wlan_vendor_attr_roam_auth attributes. Only used
+ *	if device supports QCA_WLAN_VENDOR_FEATURE_KEY_MGMT_OFFLOAD.
  *
  * @QCA_NL80211_VENDOR_SUBCMD_DO_ACS: ACS command/event which is used to
  *	invoke the ACS function in device and pass selected channels to
  *	hostapd.
+ *
+ * @QCA_NL80211_VENDOR_SUBCMD_GET_FEATURES: Command to get the features
+ *	supported by the driver. enum qca_wlan_vendor_features defines
+ *	the possible features.
  */
 enum qca_nl80211_vendor_subcmds {
 	QCA_NL80211_VENDOR_SUBCMD_UNSPEC = 0,
@@ -107,6 +114,7 @@ enum qca_nl80211_vendor_subcmds {
 	QCA_NL80211_VENDOR_SUBCMD_APFIND = 52,
 	/* 53 - reserved for QCA */
 	QCA_NL80211_VENDOR_SUBCMD_DO_ACS = 54,
+	QCA_NL80211_VENDOR_SUBCMD_GET_FEATURES = 55,
 };
 
 
@@ -124,6 +132,8 @@ enum qca_wlan_vendor_attr {
 	 * by enum qca_roaming_policy. */
 	QCA_WLAN_VENDOR_ATTR_ROAMING_POLICY = 5,
 	QCA_WLAN_VENDOR_ATTR_MAC_ADDR = 6,
+	/* used by QCA_NL80211_VENDOR_SUBCMD_GET_FEATURES */
+	QCA_WLAN_VENDOR_ATTR_FEATURE_FLAGS = 7,
 	/* keep last */
 	QCA_WLAN_VENDOR_ATTR_AFTER_LAST,
 	QCA_WLAN_VENDOR_ATTR_MAX	= QCA_WLAN_VENDOR_ATTR_AFTER_LAST - 1,
@@ -170,4 +180,18 @@ enum qca_wlan_vendor_acs_hw_mode {
 	QCA_ACS_MODE_IEEE80211AD,
 };
 
+/**
+ * enum qca_wlan_vendor_features - Vendor device/driver feature flags
+ *
+ * @QCA_WLAN_VENDOR_FEATURE_KEY_MGMT_OFFLOAD: Device supports key
+ *	management offload, a mechanism where the station's firmware
+ *	does the exchange with the AP to establish the temporal keys
+ *	after roaming, rather than having the user space wpa_supplicant do it.
+ * @NUM_QCA_WLAN_VENDOR_FEATURES: Number of assigned feature bits
+ */
+enum qca_wlan_vendor_features {
+	QCA_WLAN_VENDOR_FEATURE_KEY_MGMT_OFFLOAD	= 0,
+	NUM_QCA_WLAN_VENDOR_FEATURES /* keep last */
+};
+
 #endif /* QCA_VENDOR_H */

src/drivers/driver.h

@@ -1075,6 +1075,8 @@ struct wpa_driver_capa {
 #define WPA_DRIVER_FLAGS_MESH			0x0000000100000000ULL
 /* Driver support ACS offload */
 #define WPA_DRIVER_FLAGS_ACS_OFFLOAD		0x0000000200000000ULL
+/* Driver supports key management offload */
+#define WPA_DRIVER_FLAGS_KEY_MGMT_OFFLOAD	0x0000000400000000ULL
 	u64 flags;
 
 #define WPA_DRIVER_SMPS_MODE_STATIC			0x00000001

src/drivers/driver_nl80211.c

@@ -2347,7 +2347,7 @@ static int issue_key_mgmt_set_key(struct wpa_driver_nl80211_data *drv,
 	struct nl_msg *msg;
 	int ret;
 
-	if (!drv->key_mgmt_set_key_vendor_cmd_avail)
+	if (!(drv->capa.flags & WPA_DRIVER_FLAGS_KEY_MGMT_OFFLOAD))
 		return 0;
 
 	if (!(msg = nl80211_drv_msg(drv, 0, NL80211_CMD_VENDOR)) ||
@@ -2397,7 +2397,8 @@ static int wpa_driver_nl80211_set_key(const char *ifname, struct i802_bss *bss,
 	}
 #endif /* CONFIG_TDLS */
 
-	if (alg == WPA_ALG_PMK && drv->key_mgmt_set_key_vendor_cmd_avail) {
+	if (alg == WPA_ALG_PMK &&
+	    (drv->capa.flags & WPA_DRIVER_FLAGS_KEY_MGMT_OFFLOAD)) {
 		wpa_printf(MSG_DEBUG, "%s: calling issue_key_mgmt_set_key",
 			   __func__);
 		ret = issue_key_mgmt_set_key(drv, key, key_len);

src/drivers/driver_nl80211.h

@@ -143,8 +143,7 @@ struct wpa_driver_nl80211_data {
 	unsigned int have_low_prio_scan:1;
 	unsigned int force_connect_cmd:1;
 	unsigned int addr_changed:1;
-	unsigned int key_mgmt_set_key_vendor_cmd_avail:1;
-	unsigned int roam_auth_vendor_event_avail:1;
+	unsigned int get_features_vendor_cmd_avail:1;
 
 	u64 remain_on_chan_cookie;
 	u64 send_action_cookie;

src/drivers/driver_nl80211_capa.c

@@ -534,8 +534,8 @@ static int wiphy_info_handler(struct nl_msg *msg, void *arg)
 			case QCA_NL80211_VENDOR_SUBCMD_DFS_CAPABILITY:
 				drv->dfs_vendor_cmd_avail = 1;
 				break;
-			case QCA_NL80211_VENDOR_SUBCMD_KEY_MGMT_SET_KEY:
-				drv->key_mgmt_set_key_vendor_cmd_avail = 1;
+			case QCA_NL80211_VENDOR_SUBCMD_GET_FEATURES:
+				drv->get_features_vendor_cmd_avail = 1;
 				break;
 			case QCA_NL80211_VENDOR_SUBCMD_DO_ACS:
 				drv->capa.flags |= WPA_DRIVER_FLAGS_ACS_OFFLOAD;
@@ -558,9 +558,6 @@ static int wiphy_info_handler(struct nl_msg *msg, void *arg)
 				continue;
 			}
 			vinfo = nla_data(nl);
-			if (vinfo->subcmd ==
-			    QCA_NL80211_VENDOR_SUBCMD_KEY_MGMT_ROAM_AUTH)
-				drv->roam_auth_vendor_event_avail = 1;
 			wpa_printf(MSG_DEBUG, "nl80211: Supported vendor event: vendor_id=0x%x subcmd=%u",
 				   vinfo->vendor_id, vinfo->subcmd);
 		}
@@ -689,6 +686,77 @@ static void qca_nl80211_check_dfs_capa(struct wpa_driver_nl80211_data *drv)
 }
 
 
+struct features_info {
+	u8 *flags;
+	size_t flags_len;
+};
+
+
+static int features_info_handler(struct nl_msg *msg, void *arg)
+{
+	struct nlattr *tb[NL80211_ATTR_MAX + 1];
+	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+	struct features_info *info = arg;
+	struct nlattr *nl_vend, *attr;
+
+	nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+		  genlmsg_attrlen(gnlh, 0), NULL);
+
+	nl_vend = tb[NL80211_ATTR_VENDOR_DATA];
+	if (nl_vend) {
+		struct nlattr *tb_vendor[QCA_WLAN_VENDOR_ATTR_MAX + 1];
+
+		nla_parse(tb_vendor, QCA_WLAN_VENDOR_ATTR_MAX,
+			  nla_data(nl_vend), nla_len(nl_vend), NULL);
+
+		attr = tb_vendor[QCA_WLAN_VENDOR_ATTR_FEATURE_FLAGS];
+		if (attr) {
+			info->flags = nla_data(attr);
+			info->flags_len = nla_len(attr);
+		}
+	}
+
+	return NL_SKIP;
+}
+
+
+static int check_feature(enum qca_wlan_vendor_features feature,
+			 struct features_info *info)
+{
+	size_t index = feature / 8;
+
+	return (index < info->flags_len) &&
+		(info->flags[index] & BIT(feature % 8));
+}
+
+
+static void qca_nl80211_get_features(struct wpa_driver_nl80211_data *drv)
+{
+	struct nl_msg *msg;
+	struct features_info info;
+	int ret;
+
+	if (!drv->get_features_vendor_cmd_avail)
+		return;
+
+	if (!(msg = nl80211_drv_msg(drv, 0, NL80211_CMD_VENDOR)) ||
+	    nla_put_u32(msg, NL80211_ATTR_VENDOR_ID, OUI_QCA) ||
+	    nla_put_u32(msg, NL80211_ATTR_VENDOR_SUBCMD,
+			QCA_NL80211_VENDOR_SUBCMD_GET_FEATURES)) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	os_memset(&info, 0, sizeof(info));
+	ret = send_and_recv_msgs(drv, msg, features_info_handler, &info);
+	if (ret || !info.flags)
+		return;
+
+	if (check_feature(QCA_WLAN_VENDOR_FEATURE_KEY_MGMT_OFFLOAD, &info))
+		drv->capa.flags |= WPA_DRIVER_FLAGS_KEY_MGMT_OFFLOAD;
+}
+
+
 int wpa_driver_nl80211_capa(struct wpa_driver_nl80211_data *drv)
 {
 	struct wiphy_info_data info;
@@ -766,6 +834,7 @@ int wpa_driver_nl80211_capa(struct wpa_driver_nl80211_data *drv)
 		drv->capa.flags &= ~WPA_DRIVER_FLAGS_EAPOL_TX_STATUS;
 
 	qca_nl80211_check_dfs_capa(drv);
+	qca_nl80211_get_features(drv);
 
 	return 0;
 }

src/drivers/driver_nl80211_event.c

@@ -1690,7 +1690,8 @@ static void do_process_drv_event(struct i802_bss *bss, int cmd,
 	wpa_printf(MSG_DEBUG, "nl80211: Drv Event %d (%s) received for %s",
 		   cmd, nl80211_command_to_string(cmd), bss->ifname);
 
-	if (cmd == NL80211_CMD_ROAM && drv->roam_auth_vendor_event_avail) {
+	if (cmd == NL80211_CMD_ROAM &&
+	    (drv->capa.flags & WPA_DRIVER_FLAGS_KEY_MGMT_OFFLOAD)) {
 		/*
 		 * Device will use roam+auth vendor event to indicate
 		 * roaming, so ignore the regular roam event.