diff --git a/staticlibs/framework/com/android/net/module/util/NetworkStatsUtils.java b/staticlibs/framework/com/android/net/module/util/NetworkStatsUtils.java
new file mode 100644
index 0000000..13bbe76
--- /dev/null
+++ b/staticlibs/framework/com/android/net/module/util/NetworkStatsUtils.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2021 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.net.module.util;
+
+/**
+ * Various utilities used for NetworkStats related code.
+ *
+ * @hide
+ */
+public class NetworkStatsUtils {
+    /**
+     * Safely multiple a value by a rational.
+     * <p>
+     * Internally it uses integer-based math whenever possible, but switches
+     * over to double-based math if values would overflow.
+     * @hide
+     */
+    public static long multiplySafeByRational(long value, long num, long den) {
+        if (den == 0) {
+            throw new ArithmeticException("Invalid Denominator");
+        }
+        long x = value;
+        long y = num;
+
+        // Logic shamelessly borrowed from Math.multiplyExact()
+        long r = x * y;
+        long ax = Math.abs(x);
+        long ay = Math.abs(y);
+        if (((ax | ay) >>> 31 != 0)) {
+            // Some bits greater than 2^31 that might cause overflow
+            // Check the result using the divide operator
+            // and check for the special case of Long.MIN_VALUE * -1
+            if (((y != 0) && (r / y != x))
+                    || (x == Long.MIN_VALUE && y == -1)) {
+                // Use double math to avoid overflowing
+                return (long) (((double) num / den) * value);
+            }
+        }
+        return r / den;
+    }
+}
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/NetworkStatsUtilsTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/NetworkStatsUtilsTest.kt
new file mode 100644
index 0000000..820eb9b
--- /dev/null
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/NetworkStatsUtilsTest.kt
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2021 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.net.module.util
+
+import androidx.test.filters.SmallTest
+import androidx.test.runner.AndroidJUnit4
+import com.android.testutils.assertThrows
+import org.junit.Test
+import org.junit.runner.RunWith
+import kotlin.test.assertEquals
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class NetworkStatsUtilsTest {
+    @Test
+    fun testMultiplySafeByRational() {
+        // Verify basic cases that the method equals to a * b / c.
+        assertEquals(3 * 5 / 2, NetworkStatsUtils.multiplySafeByRational(3, 5, 2))
+
+        // Verify input with zeros.
+        assertEquals(0 * 7 / 3, NetworkStatsUtils.multiplySafeByRational(0, 7, 3))
+        assertEquals(7 * 0 / 3, NetworkStatsUtils.multiplySafeByRational(7, 0, 3))
+        assertEquals(0 * 0 / 1, NetworkStatsUtils.multiplySafeByRational(0, 0, 1))
+        assertEquals(0, NetworkStatsUtils.multiplySafeByRational(0, Long.MAX_VALUE, Long.MAX_VALUE))
+        assertEquals(0, NetworkStatsUtils.multiplySafeByRational(Long.MAX_VALUE, 0, Long.MAX_VALUE))
+        assertThrows(ArithmeticException::class.java) {
+            NetworkStatsUtils.multiplySafeByRational(7, 3, 0)
+        }
+        assertThrows(ArithmeticException::class.java) {
+            NetworkStatsUtils.multiplySafeByRational(0, 0, 0)
+        }
+
+        // Verify cases where a * b overflows.
+        assertEquals(101, NetworkStatsUtils.multiplySafeByRational(
+                101, Long.MAX_VALUE, Long.MAX_VALUE))
+        assertEquals(721, NetworkStatsUtils.multiplySafeByRational(
+                Long.MAX_VALUE, 721, Long.MAX_VALUE))
+        assertEquals(Long.MAX_VALUE, NetworkStatsUtils.multiplySafeByRational(
+                Long.MAX_VALUE, Long.MAX_VALUE, Long.MAX_VALUE))
+        assertThrows(ArithmeticException::class.java) {
+            NetworkStatsUtils.multiplySafeByRational(Long.MAX_VALUE, Long.MAX_VALUE, 0)
+        }
+    }
+}
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