diff --git a/wpa_supplicant/hidl/sta_iface.cpp b/wpa_supplicant/hidl/sta_iface.cpp
index e3a384b..1672d4c 100644
--- a/wpa_supplicant/hidl/sta_iface.cpp
+++ b/wpa_supplicant/hidl/sta_iface.cpp
@@ -8,7 +8,7 @@
  */
 
 #include "hidl_manager.h"
-#include "hidl_return_macros.h"
+#include "hidl_return_util.h"
 #include "sta_iface.h"
 
 namespace android {
@@ -17,216 +17,257 @@
 namespace supplicant {
 namespace V1_0 {
 namespace implementation {
+using hidl_return_util::validateAndCall;
 
 StaIface::StaIface(struct wpa_global *wpa_global, const char ifname[])
-    : wpa_global_(wpa_global), ifname_(ifname)
+    : wpa_global_(wpa_global), ifname_(ifname), is_valid_(true)
 {
 }
 
+void StaIface::invalidate() { is_valid_ = false; }
+bool StaIface::isValid()
+{
+	return (is_valid_ && (retrieveIfacePtr() != nullptr));
+}
+
 Return<void> StaIface::getName(getName_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(
-		    SupplicantStatusCode::FAILURE_IFACE_INVALID, ifname_);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS, ifname_);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::getNameInternal, _hidl_cb);
 }
 
 Return<void> StaIface::getType(getType_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(
-		    SupplicantStatusCode::FAILURE_IFACE_INVALID,
-		    IfaceType::STA);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS, IfaceType::STA);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::getTypeInternal, _hidl_cb);
 }
 
 Return<void> StaIface::addNetwork(addNetwork_cb _hidl_cb)
 {
-	android::sp<ISupplicantStaNetwork> network;
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(
-		    SupplicantStatusCode::FAILURE_IFACE_INVALID, network);
-	}
-
-	struct wpa_ssid *ssid = wpa_supplicant_add_network(wpa_s);
-	if (!ssid) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN, network);
-	}
-
-	HidlManager *hidl_manager = HidlManager::getInstance();
-	if (!hidl_manager ||
-	    hidl_manager->getStaNetworkHidlObjectByIfnameAndNetworkId(
-		wpa_s->ifname, ssid->id, &network)) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN, network);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS, network);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::addNetworkInternal, _hidl_cb);
 }
 
-Return<void> StaIface::removeNetwork(uint32_t id, removeNetwork_cb _hidl_cb)
+Return<void> StaIface::removeNetwork(
+    SupplicantNetworkId id, removeNetwork_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	int result = wpa_supplicant_remove_network(wpa_s, id);
-	if (result == -1) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_NETWORK_UNKNOWN);
-	}
-
-	if (result != 0) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::removeNetworkInternal, _hidl_cb, id);
 }
 
-Return<void> StaIface::getNetwork(uint32_t id, getNetwork_cb _hidl_cb)
+Return<void> StaIface::getNetwork(
+    SupplicantNetworkId id, getNetwork_cb _hidl_cb)
 {
-	android::sp<ISupplicantStaNetwork> network;
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(
-		    SupplicantStatusCode::FAILURE_IFACE_INVALID, network);
-	}
-
-	struct wpa_ssid *ssid = wpa_config_get_network(wpa_s->conf, id);
-	if (!ssid) {
-		HIDL_RETURN(
-		    SupplicantStatusCode::FAILURE_NETWORK_UNKNOWN, network);
-	}
-
-	HidlManager *hidl_manager = HidlManager::getInstance();
-	if (!hidl_manager ||
-	    hidl_manager->getStaNetworkHidlObjectByIfnameAndNetworkId(
-		wpa_s->ifname, ssid->id, &network)) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN, network);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS, network);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::getNetworkInternal, _hidl_cb, id);
 }
 
 Return<void> StaIface::listNetworks(listNetworks_cb _hidl_cb)
 {
-	std::vector<uint32_t> network_ids;
-
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(
-		    SupplicantStatusCode::FAILURE_IFACE_INVALID, network_ids);
-	}
-
-	for (struct wpa_ssid *wpa_ssid = wpa_s->conf->ssid; wpa_ssid;
-	     wpa_ssid = wpa_ssid->next) {
-		network_ids.emplace_back(wpa_ssid->id);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS, network_ids);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::listNetworksInternal, _hidl_cb);
 }
 
 Return<void> StaIface::registerCallback(
     const sp<ISupplicantStaIfaceCallback> &callback,
     registerCallback_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	HidlManager *hidl_manager = HidlManager::getInstance();
-	if (!hidl_manager ||
-	    hidl_manager->addStaIfaceCallbackHidlObject(ifname_, callback)) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::registerCallbackInternal, _hidl_cb, callback);
 }
 
 Return<void> StaIface::reassociate(reassociate_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_DISABLED);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::reassociateInternal, _hidl_cb);
 }
 
 Return<void> StaIface::reconnect(reconnect_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_DISABLED);
-	}
-	if (!wpa_s->disconnected) {
-		HIDL_RETURN(
-		    SupplicantStatusCode::FAILURE_IFACE_NOT_DISCONNECTED);
-	}
-
-	wpas_request_connection(wpa_s);
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::reconnectInternal, _hidl_cb);
 }
 
 Return<void> StaIface::disconnect(disconnect_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_DISABLED);
-	}
-
-	wpas_request_disconnection(wpa_s);
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::disconnectInternal, _hidl_cb);
 }
 
 Return<void> StaIface::setPowerSave(bool enable, setPowerSave_cb _hidl_cb)
 {
-	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	if (wpa_drv_set_p2p_powersave(wpa_s, enable, -1, -1)) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN);
-	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::setPowerSaveInternal, _hidl_cb, enable);
 }
 
 Return<void> StaIface::initiateTdlsDiscover(
-    const hidl_array<uint8_t, 6 /* 6 */> &mac_address,
-    initiateTdlsDiscover_cb _hidl_cb)
+    const hidl_array<uint8_t, 6> &mac_address, initiateTdlsDiscover_cb _hidl_cb)
+{
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::initiateTdlsDiscoverInternal, _hidl_cb, mac_address);
+}
+
+Return<void> StaIface::initiateTdlsSetup(
+    const hidl_array<uint8_t, 6> &mac_address, initiateTdlsSetup_cb _hidl_cb)
+{
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::initiateTdlsSetupInternal, _hidl_cb, mac_address);
+}
+
+Return<void> StaIface::initiateTdlsTeardown(
+    const hidl_array<uint8_t, 6> &mac_address, initiateTdlsTeardown_cb _hidl_cb)
+{
+	return validateAndCall(
+	    this, SupplicantStatusCode::FAILURE_IFACE_INVALID,
+	    &StaIface::initiateTdlsTeardownInternal, _hidl_cb, mac_address);
+}
+
+std::pair<SupplicantStatus, std::string> StaIface::getNameInternal()
+{
+	return {{SupplicantStatusCode::SUCCESS, ""}, ifname_};
+}
+
+std::pair<SupplicantStatus, IfaceType> StaIface::getTypeInternal()
+{
+	return {{SupplicantStatusCode::SUCCESS, ""}, IfaceType::STA};
+}
+
+std::pair<SupplicantStatus, sp<ISupplicantNetwork>>
+StaIface::addNetworkInternal()
+{
+	android::sp<ISupplicantStaNetwork> network;
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
+	struct wpa_ssid *ssid = wpa_supplicant_add_network(wpa_s);
+	if (!ssid) {
+		return {{SupplicantStatusCode::FAILURE_UNKNOWN, ""}, network};
+	}
+	HidlManager *hidl_manager = HidlManager::getInstance();
+	if (!hidl_manager ||
+	    hidl_manager->getStaNetworkHidlObjectByIfnameAndNetworkId(
+		wpa_s->ifname, ssid->id, &network)) {
+		return {{SupplicantStatusCode::FAILURE_UNKNOWN, ""}, network};
+	}
+	return {{SupplicantStatusCode::SUCCESS, ""}, network};
+}
+
+SupplicantStatus StaIface::removeNetworkInternal(SupplicantNetworkId id)
 {
 	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
+	int result = wpa_supplicant_remove_network(wpa_s, id);
+	if (result == -1) {
+		return {SupplicantStatusCode::FAILURE_NETWORK_UNKNOWN, ""};
 	}
-
-	if (!mac_address.data()) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_ARGS_INVALID);
+	if (result != 0) {
+		return {SupplicantStatusCode::FAILURE_UNKNOWN, ""};
 	}
+	return {SupplicantStatusCode::SUCCESS, ""};
+}
 
+std::pair<SupplicantStatus, sp<ISupplicantNetwork>>
+StaIface::getNetworkInternal(SupplicantNetworkId id)
+{
+	android::sp<ISupplicantStaNetwork> network;
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
+	struct wpa_ssid *ssid = wpa_config_get_network(wpa_s->conf, id);
+	if (!ssid) {
+		return {{SupplicantStatusCode::FAILURE_NETWORK_UNKNOWN, ""},
+			network};
+	}
+	HidlManager *hidl_manager = HidlManager::getInstance();
+	if (!hidl_manager ||
+	    hidl_manager->getStaNetworkHidlObjectByIfnameAndNetworkId(
+		wpa_s->ifname, ssid->id, &network)) {
+		return {{SupplicantStatusCode::FAILURE_UNKNOWN, ""}, network};
+	}
+	return {{SupplicantStatusCode::SUCCESS, ""}, network};
+}
+
+std::pair<SupplicantStatus, std::vector<SupplicantNetworkId>>
+StaIface::listNetworksInternal()
+{
+	std::vector<SupplicantNetworkId> network_ids;
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
+	for (struct wpa_ssid *wpa_ssid = wpa_s->conf->ssid; wpa_ssid;
+	     wpa_ssid = wpa_ssid->next) {
+		network_ids.emplace_back(wpa_ssid->id);
+	}
+	return {{SupplicantStatusCode::SUCCESS, ""}, std::move(network_ids)};
+}
+
+SupplicantStatus StaIface::registerCallbackInternal(
+    const sp<ISupplicantStaIfaceCallback> &callback)
+{
+	HidlManager *hidl_manager = HidlManager::getInstance();
+	if (!hidl_manager ||
+	    hidl_manager->addStaIfaceCallbackHidlObject(ifname_, callback)) {
+		return {SupplicantStatusCode::FAILURE_UNKNOWN, ""};
+	}
+	return {SupplicantStatusCode::SUCCESS, ""};
+}
+
+SupplicantStatus StaIface::reassociateInternal()
+{
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
+	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
+		return {SupplicantStatusCode::FAILURE_IFACE_DISABLED, ""};
+	}
+	wpas_request_connection(wpa_s);
+	return {SupplicantStatusCode::SUCCESS, ""};
+}
+
+SupplicantStatus StaIface::reconnectInternal()
+{
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
+	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
+		return {SupplicantStatusCode::FAILURE_IFACE_DISABLED, ""};
+	}
+	if (!wpa_s->disconnected) {
+		return {SupplicantStatusCode::FAILURE_IFACE_NOT_DISCONNECTED,
+			""};
+	}
+	wpas_request_connection(wpa_s);
+	return {SupplicantStatusCode::SUCCESS, ""};
+}
+
+SupplicantStatus StaIface::disconnectInternal()
+{
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
+	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
+		return {SupplicantStatusCode::FAILURE_IFACE_DISABLED, ""};
+	}
+	wpas_request_disconnection(wpa_s);
+	return {SupplicantStatusCode::SUCCESS, ""};
+}
+
+SupplicantStatus StaIface::setPowerSaveInternal(bool enable)
+{
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
+	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
+		return {SupplicantStatusCode::FAILURE_IFACE_DISABLED, ""};
+	}
+	if (wpa_drv_set_p2p_powersave(wpa_s, enable, -1, -1)) {
+		return {SupplicantStatusCode::FAILURE_UNKNOWN, ""};
+	}
+	return {SupplicantStatusCode::SUCCESS, ""};
+}
+
+SupplicantStatus StaIface::initiateTdlsDiscoverInternal(
+    const std::array<uint8_t, 6> &mac_address)
+{
+	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
 	int ret;
 	const u8 *peer = mac_address.data();
 	if (wpa_tdls_is_external_setup(wpa_s->wpa)) {
@@ -235,25 +276,15 @@
 		ret = wpa_drv_tdls_oper(wpa_s, TDLS_DISCOVERY_REQ, peer);
 	}
 	if (ret) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN);
+		return {SupplicantStatusCode::FAILURE_UNKNOWN, ""};
 	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return {SupplicantStatusCode::SUCCESS, ""};
 }
 
-Return<void> StaIface::initiateTdlsSetup(
-    const hidl_array<uint8_t, 6 /* 6 */> &mac_address,
-    initiateTdlsSetup_cb _hidl_cb)
+SupplicantStatus StaIface::initiateTdlsSetupInternal(
+    const std::array<uint8_t, 6> &mac_address)
 {
 	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	if (!mac_address.data()) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_ARGS_INVALID);
-	}
-
 	int ret;
 	const u8 *peer = mac_address.data();
 	if (wpa_tdls_is_external_setup(wpa_s->wpa) &&
@@ -264,25 +295,15 @@
 		ret = wpa_drv_tdls_oper(wpa_s, TDLS_SETUP, peer);
 	}
 	if (ret) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN);
+		return {SupplicantStatusCode::FAILURE_UNKNOWN, ""};
 	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return {SupplicantStatusCode::SUCCESS, ""};
 }
 
-Return<void> StaIface::initiateTdlsTeardown(
-    const hidl_array<uint8_t, 6 /* 6 */> &mac_address,
-    initiateTdlsTeardown_cb _hidl_cb)
+SupplicantStatus StaIface::initiateTdlsTeardownInternal(
+    const std::array<uint8_t, 6> &mac_address)
 {
 	struct wpa_supplicant *wpa_s = retrieveIfacePtr();
-	if (!wpa_s) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_IFACE_INVALID);
-	}
-
-	if (!mac_address.data()) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_ARGS_INVALID);
-	}
-
 	int ret;
 	const u8 *peer = mac_address.data();
 	if (wpa_tdls_is_external_setup(wpa_s->wpa) &&
@@ -292,12 +313,10 @@
 	} else {
 		ret = wpa_drv_tdls_oper(wpa_s, TDLS_TEARDOWN, peer);
 	}
-
 	if (ret) {
-		HIDL_RETURN(SupplicantStatusCode::FAILURE_UNKNOWN);
+		return {SupplicantStatusCode::FAILURE_UNKNOWN, ""};
 	}
-
-	HIDL_RETURN(SupplicantStatusCode::SUCCESS);
+	return {SupplicantStatusCode::SUCCESS, ""};
 }
 
 /**
diff --git a/wpa_supplicant/hidl/sta_iface.h b/wpa_supplicant/hidl/sta_iface.h
index f246bbc..8b9755a 100644
--- a/wpa_supplicant/hidl/sta_iface.h
+++ b/wpa_supplicant/hidl/sta_iface.h
@@ -10,6 +10,9 @@
 #ifndef WPA_SUPPLICANT_HIDL_STA_IFACE_H
 #define WPA_SUPPLICANT_HIDL_STA_IFACE_H
 
+#include <array>
+#include <vector>
+
 #include <android-base/macros.h>
 
 #include <android/hardware/wifi/supplicant/1.0/ISupplicantStaIface.h>
@@ -43,14 +46,29 @@
 public:
 	StaIface(struct wpa_global* wpa_global, const char ifname[]);
 	~StaIface() override = default;
+	// HIDL does not provide a built-in mechanism to let the server
+	// invalidate a HIDL interface object after creation. If any client
+	// process holds onto a reference to the object in their context,
+	// any method calls on that reference will continue to be directed to
+	// the server.
+	// However Supplicant HAL needs to control the lifetime of these
+	// objects. So, add a public |invalidate| method to all |Iface| and
+	// |Network| objects.
+	// This will be used to mark an object invalid when the corresponding
+	// iface or network is removed.
+	// All HIDL method implementations should check if the object is still
+	// marked valid before processing them.
+	void invalidate();
+	bool isValid();
 
 	// Hidl methods exposed.
 	Return<void> getName(getName_cb _hidl_cb) override;
 	Return<void> getType(getType_cb _hidl_cb) override;
 	Return<void> addNetwork(addNetwork_cb _hidl_cb) override;
 	Return<void> removeNetwork(
-	    uint32_t id, removeNetwork_cb _hidl_cb) override;
-	Return<void> getNetwork(uint32_t id, getNetwork_cb _hidl_cb) override;
+	    SupplicantNetworkId id, removeNetwork_cb _hidl_cb) override;
+	Return<void> getNetwork(
+	    SupplicantNetworkId id, getNetwork_cb _hidl_cb) override;
 	Return<void> listNetworks(listNetworks_cb _hidl_cb) override;
 	Return<void> registerCallback(
 	    const sp<ISupplicantStaIfaceCallback>& callback,
@@ -61,16 +79,39 @@
 	Return<void> setPowerSave(
 	    bool enable, setPowerSave_cb _hidl_cb) override;
 	Return<void> initiateTdlsDiscover(
-	    const hidl_array<uint8_t, 6 /* 6 */>& mac_address,
+	    const hidl_array<uint8_t, 6>& mac_address,
 	    initiateTdlsDiscover_cb _hidl_cb) override;
 	Return<void> initiateTdlsSetup(
-	    const hidl_array<uint8_t, 6 /* 6 */>& mac_address,
+	    const hidl_array<uint8_t, 6>& mac_address,
 	    initiateTdlsSetup_cb _hidl_cb) override;
 	Return<void> initiateTdlsTeardown(
-	    const hidl_array<uint8_t, 6 /* 6 */>& mac_address,
+	    const hidl_array<uint8_t, 6>& mac_address,
 	    initiateTdlsTeardown_cb _hidl_cb) override;
 
 private:
+	// Corresponding worker functions for the HIDL methods.
+	std::pair<SupplicantStatus, std::string> getNameInternal();
+	std::pair<SupplicantStatus, IfaceType> getTypeInternal();
+	std::pair<SupplicantStatus, sp<ISupplicantNetwork>>
+	addNetworkInternal();
+	SupplicantStatus removeNetworkInternal(SupplicantNetworkId id);
+	std::pair<SupplicantStatus, sp<ISupplicantNetwork>> getNetworkInternal(
+	    SupplicantNetworkId id);
+	std::pair<SupplicantStatus, std::vector<SupplicantNetworkId>>
+	listNetworksInternal();
+	SupplicantStatus registerCallbackInternal(
+	    const sp<ISupplicantStaIfaceCallback>& callback);
+	SupplicantStatus reassociateInternal();
+	SupplicantStatus reconnectInternal();
+	SupplicantStatus disconnectInternal();
+	SupplicantStatus setPowerSaveInternal(bool enable);
+	SupplicantStatus initiateTdlsDiscoverInternal(
+	    const std::array<uint8_t, 6>& mac_address);
+	SupplicantStatus initiateTdlsSetupInternal(
+	    const std::array<uint8_t, 6>& mac_address);
+	SupplicantStatus initiateTdlsTeardownInternal(
+	    const std::array<uint8_t, 6>& mac_address);
+
 	struct wpa_supplicant* retrieveIfacePtr();
 
 	// Reference to the global wpa_struct. This is assumed to be valid for
@@ -78,6 +119,7 @@
 	const struct wpa_global* wpa_global_;
 	// Name of the iface this hidl object controls
 	const std::string ifname_;
+	bool is_valid_;
 
 	DISALLOW_COPY_AND_ASSIGN(StaIface);
 };