diff --git a/staticlibs/device/com/android/net/module/util/structs/Ipv4Header.java b/staticlibs/device/com/android/net/module/util/structs/Ipv4Header.java
new file mode 100644
index 0000000..5249454
--- /dev/null
+++ b/staticlibs/device/com/android/net/module/util/structs/Ipv4Header.java
@@ -0,0 +1,94 @@
+/*
+ * 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.structs;
+
+import androidx.annotation.VisibleForTesting;
+
+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.net.Inet4Address;
+
+/**
+ * L3 IPv4 header as per https://tools.ietf.org/html/rfc791.
+ * This class doesn't contain options field.
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |Version|  IHL  |Type of Service|          Total Length         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |         Identification        |Flags|      Fragment Offset    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |  Time to Live |    Protocol   |         Header Checksum       |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                       Source Address                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                    Destination Address                        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+public class Ipv4Header extends Struct {
+    // IP Version=IPv4, IHL is always 5(*4bytes) because options are not supported.
+    @VisibleForTesting
+    public static final byte IPHDR_VERSION_IHL = 0x45;
+
+    @Field(order = 0, type = Type.S8)
+    // version (4 bits), IHL (4 bits)
+    public final byte vi;
+    @Field(order = 1, type = Type.S8)
+    public final byte tos;
+    @Field(order = 2, type = Type.U16)
+    public final int totalLength;
+    @Field(order = 3, type = Type.S16)
+    public final short id;
+    @Field(order = 4, type = Type.S16)
+    // flags (3 bits), fragment offset (13 bits)
+    public final short flagsAndFragmentOffset;
+    @Field(order = 5, type = Type.U8)
+    public final short ttl;
+    @Field(order = 6, type = Type.S8)
+    public final byte protocol;
+    @Field(order = 7, type = Type.S16)
+    public final short checksum;
+    @Field(order = 8, type = Type.Ipv4Address)
+    public final Inet4Address srcIp;
+    @Field(order = 9, type = Type.Ipv4Address)
+    public final Inet4Address dstIp;
+
+    public Ipv4Header(final byte tos, final int totalLength, final short id,
+            final short flagsAndFragmentOffset, final short ttl, final byte protocol,
+            final short checksum, final Inet4Address srcIp, final Inet4Address dstIp) {
+        this(IPHDR_VERSION_IHL, tos, totalLength, id, flagsAndFragmentOffset, ttl,
+                protocol, checksum, srcIp, dstIp);
+    }
+
+    private Ipv4Header(final byte vi, final byte tos, final int totalLength, final short id,
+            final short flagsAndFragmentOffset, final short ttl, final byte protocol,
+            final short checksum, final Inet4Address srcIp, final Inet4Address dstIp) {
+        this.vi = vi;
+        this.tos = tos;
+        this.totalLength = totalLength;
+        this.id = id;
+        this.flagsAndFragmentOffset = flagsAndFragmentOffset;
+        this.ttl = ttl;
+        this.protocol = protocol;
+        this.checksum = checksum;
+        this.srcIp = srcIp;
+        this.dstIp = dstIp;
+    }
+}