diff --git a/service-t/src/com/android/server/net/BpfInterfaceMapUpdater.java b/service-t/src/com/android/server/net/BpfInterfaceMapUpdater.java
index 3b44d81..ed889e1 100644
--- a/service-t/src/com/android/server/net/BpfInterfaceMapUpdater.java
+++ b/service-t/src/com/android/server/net/BpfInterfaceMapUpdater.java
@@ -136,4 +136,19 @@
             mHandler.post(() -> addInterface(ifName));
         }
     }
+
+    /** get interface name by interface index from bpf map */
+    public String getIfNameByIndex(final long index) {
+        try {
+            final InterfaceMapValue value = mBpfMap.getValue(new U32(index));
+            if (value == null) {
+                Log.e(TAG, "No if name entry for index " + index);
+                return null;
+            }
+            return value.getInterfaceNameString();
+        } catch (ErrnoException e) {
+            Log.e(TAG, "Failed to get entry for index " + index + ": " + e);
+            return null;
+        }
+    }
 }
diff --git a/service-t/src/com/android/server/net/InterfaceMapValue.java b/service-t/src/com/android/server/net/InterfaceMapValue.java
index 42c0044..95da981 100644
--- a/service-t/src/com/android/server/net/InterfaceMapValue.java
+++ b/service-t/src/com/android/server/net/InterfaceMapValue.java
@@ -16,20 +16,45 @@
 package com.android.server.net;
 
 import com.android.net.module.util.Struct;
-import com.android.net.module.util.Struct.Field;
-import com.android.net.module.util.Struct.Type;
+
+import java.util.Arrays;
 
 /**
  * The value of bpf interface index map which is used for NetworkStatsService.
  */
 public class InterfaceMapValue extends Struct {
+    private static final int IF_NAME_SIZE = 16;
+
     @Field(order = 0, type = Type.ByteArray, arraysize = 16)
     public final byte[] interfaceName;
 
     public InterfaceMapValue(String iface) {
-        final byte[] ifaceArray = iface.getBytes();
-        interfaceName = new byte[16];
         // All array bytes after the interface name, if any, must be 0.
-        System.arraycopy(ifaceArray, 0, interfaceName, 0, ifaceArray.length);
+        interfaceName = Arrays.copyOf(iface.getBytes(), IF_NAME_SIZE);
+    }
+
+    /**
+     * Constructor for Struct#parse. Build this struct from byte array of interface name.
+     *
+     * @param ifName Byte array of interface name, length is expected to be IF_NAME_SIZE(16).
+     *               If longer or shorter, interface name will be truncated or padded with zeros.
+     *               All array bytes after the interface name, if any, must be 0.
+     */
+    public InterfaceMapValue(final byte[] ifName) {
+        interfaceName = Arrays.copyOf(ifName, IF_NAME_SIZE);
+    }
+
+    /** Returns the length of the null-terminated string. */
+    private int strlen(byte[] str) {
+        for (int i = 0; i < str.length; ++i) {
+            if (str[i] == '\0') {
+                return i;
+            }
+        }
+        return str.length;
+    }
+
+    public String getInterfaceNameString() {
+        return new String(interfaceName, 0 /* offset */,  strlen(interfaceName));
     }
 }
diff --git a/tests/unit/java/com/android/server/net/BpfInterfaceMapUpdaterTest.java b/tests/unit/java/com/android/server/net/BpfInterfaceMapUpdaterTest.java
index c6852d1..6f551c5 100644
--- a/tests/unit/java/com/android/server/net/BpfInterfaceMapUpdaterTest.java
+++ b/tests/unit/java/com/android/server/net/BpfInterfaceMapUpdaterTest.java
@@ -16,7 +16,13 @@
 
 package com.android.server.net;
 
+import static android.system.OsConstants.EPERM;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
@@ -27,6 +33,7 @@
 import android.os.Build;
 import android.os.Handler;
 import android.os.test.TestLooper;
+import android.system.ErrnoException;
 
 import androidx.test.filters.SmallTest;
 
@@ -36,6 +43,7 @@
 import com.android.net.module.util.Struct.U32;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRunner;
+import com.android.testutils.TestBpfMap;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -56,7 +64,8 @@
     private final TestLooper mLooper = new TestLooper();
     private BaseNetdUnsolicitedEventListener mListener;
     private BpfInterfaceMapUpdater mUpdater;
-    @Mock private IBpfMap<U32, InterfaceMapValue> mBpfMap;
+    private IBpfMap<U32, InterfaceMapValue> mBpfMap =
+            spy(new TestBpfMap<>(U32.class, InterfaceMapValue.class));
     @Mock private INetd mNetd;
     @Mock private Context mContext;
 
@@ -118,4 +127,21 @@
         mLooper.dispatchAll();
         verifyNoMoreInteractions(mBpfMap);
     }
+
+    @Test
+    public void testGetIfNameByIndex() throws Exception {
+        mBpfMap.updateEntry(new U32(TEST_INDEX), new InterfaceMapValue(TEST_INTERFACE_NAME));
+        assertEquals(TEST_INTERFACE_NAME, mUpdater.getIfNameByIndex(TEST_INDEX));
+    }
+
+    @Test
+    public void testGetIfNameByIndexNoEntry() {
+        assertNull(mUpdater.getIfNameByIndex(TEST_INDEX));
+    }
+
+    @Test
+    public void testGetIfNameByIndexException() throws Exception {
+        doThrow(new ErrnoException("", EPERM)).when(mBpfMap).getValue(new U32(TEST_INDEX));
+        assertNull(mUpdater.getIfNameByIndex(TEST_INDEX));
+    }
 }
diff --git a/tests/unit/java/com/android/server/net/InterfaceMapValueTest.java b/tests/unit/java/com/android/server/net/InterfaceMapValueTest.java
new file mode 100644
index 0000000..ee13d5f
--- /dev/null
+++ b/tests/unit/java/com/android/server/net/InterfaceMapValueTest.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2022 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 com.android.server.net;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class InterfaceMapValueTest {
+    private static final String IF_NAME = "wlan0";
+    private static final byte[] IF_NAME_BYTE = new byte[]{'w', 'l', 'a', 'n', '0'};
+    private static final byte[] IF_NAME_BYTE_WITH_PADDING =
+            new byte[]{'w', 'l', 'a', 'n', '0', 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0}; // IF_NAME_BYTE_WITH_PADDING.length = 16
+    private static final byte[] IF_NAME_BYTE_LONG =
+            new byte[]{'w', 'l', 'a', 'n', '0', 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0}; // IF_NAME_BYTE_LONG.length = 24
+
+    @Test
+    public void testInterfaceMapValueFromString() {
+        final InterfaceMapValue value = new InterfaceMapValue(IF_NAME);
+        assertArrayEquals(IF_NAME_BYTE_WITH_PADDING, value.interfaceName);
+    }
+
+    @Test
+    public void testInterfaceMapValueFromByte() {
+        final InterfaceMapValue value = new InterfaceMapValue(IF_NAME_BYTE_WITH_PADDING);
+        assertArrayEquals(IF_NAME_BYTE_WITH_PADDING, value.interfaceName);
+    }
+
+    @Test
+    public void testInterfaceMapValueFromByteShort() {
+        final InterfaceMapValue value = new InterfaceMapValue(IF_NAME_BYTE);
+        assertArrayEquals(IF_NAME_BYTE_WITH_PADDING, value.interfaceName);
+    }
+
+    @Test
+    public void testInterfaceMapValueFromByteLong() {
+        final InterfaceMapValue value = new InterfaceMapValue(IF_NAME_BYTE_LONG);
+        assertArrayEquals(IF_NAME_BYTE_WITH_PADDING, value.interfaceName);
+    }
+
+    @Test
+    public void testGetInterfaceNameString() {
+        final InterfaceMapValue value = new InterfaceMapValue(IF_NAME_BYTE_WITH_PADDING);
+        assertEquals(IF_NAME, value.getInterfaceNameString());
+    }
+}