diff --git a/wifi/supplicant/1.0/ISupplicantIfaceCallback.hal b/wifi/supplicant/1.0/ISupplicantIfaceCallback.hal
new file mode 100644
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+++ b/wifi/supplicant/1.0/ISupplicantIfaceCallback.hal
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+/*
+ * Copyright 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.wifi.supplicant@1.0;
+
+/**
+ * Callback Interface exposed by the wpa_supplicant service
+ * for each interface (ISupplicantIface).
+ *
+ * Clients need to host an instance of this HIDL interface object and
+ * pass a reference of the object to wpa_supplicant via the
+ * corresponding |ISupplicantIface.registerCallback| method.
+ */
+interface ISupplicantIfaceCallback {
+  /** Various states of the interface reported by |onStateChanged|.*/
+  enum State : uint32_t {
+    /**
+     * This state indicates that client is not associated, but is likely to
+     * start looking for an access point. This state is entered when a
+     * connection is lost.
+     */
+    DISCONNECTED = 0,
+    /**
+     * This state is entered if the network interface is disabled, e.g.,
+     * due to rfkill. wpa_supplicant refuses any new operations that would
+     * use the radio until the interface has been enabled.
+     */
+    INTERFACE_DISABLED = 1,
+    /**
+     * This state is entered if there are no enabled networks in the
+     * configuration. wpa_supplicant is not trying to associate with a new
+     * network and external interaction (e.g., ctrl_iface call to add or
+     * enable a network) is needed to start association.
+     */
+    INACTIVE = 2,
+    /**
+     * This state is entered when wpa_supplicant starts scanning for a
+     * network.
+     */
+    SCANNING = 3,
+    /**
+     * This state is entered when wpa_supplicant has found a suitable BSS
+     * to authenticate with and the driver is configured to try to
+     * authenticate with this BSS. This state is used only with drivers
+     * that use wpa_supplicant as the SME.
+     */
+    AUTHENTICATING = 4,
+    /**
+     * This state is entered when wpa_supplicant has found a suitable BSS
+     * to associate with and the driver is configured to try to associate
+     * with this BSS in ap_scan=1 mode. When using ap_scan=2 mode, this
+     * state is entered when the driver is configured to try to associate
+     * with a network using the configured SSID and security policy.
+     */
+    ASSOCIATING = 5,
+    /**
+     * This state is entered when the driver reports that association has
+     * been successfully completed with an AP. If IEEE 802.1X is used
+     * (with or without WPA/WPA2), wpa_supplicant remains in this state
+     * until the IEEE 802.1X/EAPOL authentication has been completed.
+     */
+    ASSOCIATED = 6,
+    /**
+     * This state is entered when WPA/WPA2 4-Way Handshake is started. In
+     * case of WPA-PSK, this happens when receiving the first EAPOL-Key
+     * frame after association. In case of WPA-EAP, this state is entered
+     * when the IEEE 802.1X/EAPOL authentication has been completed.
+     */
+    FOURWAY_HANDSHAKE = 7,
+    /**
+     * This state is entered when 4-Way Key Handshake has been completed
+     * (i.e., when the supplicant sends out message 4/4) and when Group
+     * Key rekeying is started by the AP (i.e., when supplicant receives
+     * message 1/2).
+     */
+    GROUP_HANDSHAKE = 8,
+    /**
+     * This state is entered when the full authentication process is
+     * completed. In case of WPA2, this happens when the 4-Way Handshake is
+     * successfully completed. With WPA, this state is entered after the
+     * Group Key Handshake; with IEEE 802.1X (non-WPA) connection is
+     * completed after dynamic keys are received (or if not used, after
+     * the EAP authentication has been completed). With static WEP keys and
+     * plaintext connections, this state is entered when an association
+     * has been completed.
+     *
+     * This state indicates that the supplicant has completed its
+     * processing for the association phase and that data connection is
+     * fully configured.
+     */
+    COMPLETED = 9
+  };
+
+  /**
+   * Used to indicate that a new network has been added.
+   *
+   * @param id Network ID allocated to the corresponding network.
+   */
+  oneway onNetworkAdded(SupplicantNetworkId id);
+
+  /**
+   * Used to indicate that a network has been removed.
+   *
+   * @param id Network ID allocated to the corresponding network.
+   */
+  oneway onNetworkRemoved(SupplicantNetworkId id);
+
+  /**
+   * Used to indicate a state change event on this particular iface. If this
+   * event is triggered by a particular network, the |SupplicantNetworkId|,
+   * |ssid|, |bssid| parameters must indicate the parameters of the network/AP
+   * which cased this state transition.
+   *
+   * @param newState New State of the interface. This must be one of the |State|
+   *        values above.
+   * @param bssid BSSID of the corresponding AP which caused this state
+   *        change event. This must be zero'ed if this event is not
+   *        specific to a particular network.
+   * @param id ID of the corresponding network which caused this
+   *        state change event. This must be invalid (UINT32_MAX) if this
+   *        event is not specific to a particular network.
+   * @param ssid SSID of the corresponding network which caused this state
+   *        change event. This must be empty if this event is not specific
+   *        to a particular network.
+   */
+  oneway onStateChanged(
+      State newState, Bssid bssid, SupplicantNetworkId id, Ssid ssid);
+};