diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java
index ef865af..233e1c9 100644
--- a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java
@@ -220,5 +220,5 @@
         assertArrayEquals(EXPECTED_PROTOCOL_ERROR_DATA_NONE, protocolException.getErrorData());
     }
 
-    // TODO(b/155821007): Verify rekey process and handling IKE_AUTH failure
+    // TODO(b/155821007): Verify handling IKE_AUTH failure
 }
diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionRekeyTest.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionRekeyTest.java
new file mode 100644
index 0000000..f954fcd
--- /dev/null
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionRekeyTest.java
@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2020 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.net.ipsec.ike.cts;
+
+import static com.android.internal.util.HexDump.hexStringToByteArray;
+
+import android.net.InetAddresses;
+import android.net.LinkAddress;
+import android.net.ipsec.ike.IkeFqdnIdentification;
+import android.net.ipsec.ike.IkeSession;
+import android.net.ipsec.ike.IkeSessionParams;
+import android.net.ipsec.ike.IkeTrafficSelector;
+import android.net.ipsec.ike.cts.IkeTunUtils.PortPair;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Arrays;
+
+/**
+ * Explicitly test transport mode Child SA so that devices without FEATURE_IPSEC_TUNNELS can be test
+ * covered. Tunnel mode Child SA setup has been tested in IkeSessionPskTest. Rekeying process is
+ * independent from Child SA mode.
+ */
+@RunWith(AndroidJUnit4.class)
+public class IkeSessionRekeyTest extends IkeSessionTestBase {
+    // This value is align with the test vectors hex that are generated in an IPv4 environment
+    private static final IkeTrafficSelector TRANSPORT_MODE_INBOUND_TS =
+            new IkeTrafficSelector(
+                    MIN_PORT,
+                    MAX_PORT,
+                    InetAddresses.parseNumericAddress("172.58.35.40"),
+                    InetAddresses.parseNumericAddress("172.58.35.40"));
+
+    private IkeSession openIkeSessionWithRemoteAddress(InetAddress remoteAddress) {
+        IkeSessionParams ikeParams =
+                new IkeSessionParams.Builder(sContext)
+                        .setNetwork(mTunNetwork)
+                        .setServerHostname(remoteAddress.getHostAddress())
+                        .addSaProposal(SaProposalTest.buildIkeSaProposalWithNormalModeCipher())
+                        .addSaProposal(SaProposalTest.buildIkeSaProposalWithCombinedModeCipher())
+                        .setLocalIdentification(new IkeFqdnIdentification(LOCAL_HOSTNAME))
+                        .setRemoteIdentification(new IkeFqdnIdentification(REMOTE_HOSTNAME))
+                        .setAuthPsk(IKE_PSK)
+                        .build();
+        return new IkeSession(
+                sContext,
+                ikeParams,
+                buildTransportModeChildParamsWithTs(
+                        TRANSPORT_MODE_INBOUND_TS, TRANSPORT_MODE_OUTBOUND_TS),
+                mUserCbExecutor,
+                mIkeSessionCallback,
+                mFirstChildSessionCallback);
+    }
+
+    private byte[] buildInboundPkt(PortPair outPktSrcDestPortPair, String inboundDataHex)
+            throws Exception {
+        // Build inbound packet by flipping the outbound packet addresses and ports
+        return IkeTunUtils.buildIkePacket(
+                mRemoteAddress,
+                mLocalAddress,
+                outPktSrcDestPortPair.dstPort,
+                outPktSrcDestPortPair.srcPort,
+                true /* useEncap */,
+                hexStringToByteArray(inboundDataHex));
+    }
+
+    @Test
+    public void testRekeyIke() throws Exception {
+        final String ikeInitResp =
+                "46B8ECA1E0D72A1866B5248CF6C7472D21202220000000000000015022000030"
+                        + "0000002C010100040300000C0100000C800E0100030000080300000C03000008"
+                        + "0200000500000008040000022800008800020000920D3E830E7276908209212D"
+                        + "E5A7F2A48706CFEF1BE8CB6E3B173B8B4E0D8C2DC626271FF1B13A88619E569E"
+                        + "7B03C3ED2C127390749CDC7CDC711D0A8611E4457FFCBC4F0981B3288FBF58EA"
+                        + "3E8B70E27E76AE70117FBBCB753660ADDA37EB5EB3A81BED6A374CCB7E132C2A"
+                        + "94BFCE402DC76B19C158B533F6B1F2ABF01ACCC329000024B302CA2FB85B6CF4"
+                        + "02313381246E3C53828D787F6DFEA6BD62D6405254AEE6242900001C00004004"
+                        + "7A1682B06B58596533D00324886EF1F20EF276032900001C00004005BF633E31"
+                        + "F9984B29A62E370BB2770FC09BAEA665290000080000402E290000100000402F"
+                        + "00020003000400050000000800004014";
+        final String ikeAuthResp =
+                "46B8ECA1E0D72A1866B5248CF6C7472D2E20232000000001000000F0240000D4"
+                        + "10166CA8647F56123DE74C17FA5E256043ABF73216C812EE32EE1BB01EAF4A82"
+                        + "DC107AB3ADBFEE0DEA5EEE10BDD5D43178F4C975C7C775D252273BB037283C7F"
+                        + "236FE34A6BCE4833816897075DB2055B9FFD66DFA45A0A89A8F70AFB59431EED"
+                        + "A20602FB614369D12906D3355CF7298A5D25364ABBCC75A9D88E0E6581449FCD"
+                        + "4E361A39E00EFD1FD0A69651F63DB46C12470226AA21BA5EFF48FAF0B6DDF61C"
+                        + "B0A69392CE559495EEDB4D1C1D80688434D225D57210A424C213F7C993D8A456"
+                        + "38153FBD194C5E247B592D1D048DB4C8";
+        final String rekeyIkeCreateReq =
+                "46B8ECA1E0D72A1866B5248CF6C7472D2E202400000000000000013021000114"
+                        + "13743670039E308A8409BA5FD47B67F956B36FEE88AC3B70BB5D789B8218A135"
+                        + "1B3D83E260E87B3EDB1BF064F09D4DC2611AEDBC99951B4B2DE767BD4AA2ACC3"
+                        + "3653549CFC66B75869DF003CDC9A137A9CC27776AD5732B34203E74BE8CA4858"
+                        + "1D5C0D9C9CA52D680EB299B4B21C7FA25FFEE174D57015E0FF2EAED653AAD95C"
+                        + "071ABE269A8C2C9FBC1188E07550EB992F910D4CA9689E44BA66DE0FABB2BDF9"
+                        + "8DD377186DBB25EF9B68B027BB2A27981779D8303D88D7CE860010A42862D50B"
+                        + "1E0DBFD3D27C36F14809D7F493B2B96A65534CF98B0C32AD5219AD77F681AC04"
+                        + "9D5CB89A0230A91A243FA7F16251B0D9B4B65E7330BEEAC9663EF4578991EAC8"
+                        + "46C19EBB726E7D113F1D0D601102C05E";
+        final String rekeyIkeDeleteReq =
+                "46B8ECA1E0D72A1866B5248CF6C7472D2E20250000000001000000502A000034"
+                        + "02E40C0C7B1ED977729F705BB9B643FAC513A1070A6EB28ECD2AEA8A441ADC05"
+                        + "7841382A7967BBF116AE52496590B2AD";
+        final String deleteIkeReq =
+                "7D3DEDC65407D1FC9361C8CF8C47162A2E20250800000000000000502A000034"
+                        + "201915C9E4E9173AA9EE79F3E02FE2D4954B22085C66D164762C34D347C16E9F"
+                        + "FC5F7F114428C54D8D915860C57B1BC1";
+        final long newIkeDeterministicInitSpi = Long.parseLong("7D3DEDC65407D1FC", 16);
+
+        // Open IKE Session
+        IkeSession ikeSession = openIkeSessionWithRemoteAddress(mRemoteAddress);
+        PortPair localRemotePorts = performSetupIkeAndFirstChildBlocking(ikeInitResp, ikeAuthResp);
+
+        // Local request message ID starts from 2 because there is one IKE_INIT message and a single
+        // IKE_AUTH message.
+        int expectedReqMsgId = 2;
+        int expectedRespMsgId = 0;
+
+        verifyIkeSessionSetupBlocking();
+        verifyChildSessionSetupBlocking(
+                mFirstChildSessionCallback,
+                Arrays.asList(TRANSPORT_MODE_INBOUND_TS),
+                Arrays.asList(TRANSPORT_MODE_OUTBOUND_TS),
+                new ArrayList<LinkAddress>());
+        IpSecTransformCallRecord firstTransformRecordA =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        IpSecTransformCallRecord firstTransformRecordB =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        verifyCreateIpSecTransformPair(firstTransformRecordA, firstTransformRecordB);
+
+        // Inject rekey IKE requests
+        mTunUtils.injectPacket(buildInboundPkt(localRemotePorts, rekeyIkeCreateReq));
+        mTunUtils.awaitResp(
+                IKE_DETERMINISTIC_INITIATOR_SPI, expectedRespMsgId++, true /* expectedUseEncap */);
+        mTunUtils.injectPacket(buildInboundPkt(localRemotePorts, rekeyIkeDeleteReq));
+        mTunUtils.awaitResp(
+                IKE_DETERMINISTIC_INITIATOR_SPI, expectedRespMsgId++, true /* expectedUseEncap */);
+
+        // IKE has been rekeyed, reset message IDs
+        expectedReqMsgId = 0;
+        expectedRespMsgId = 0;
+
+        // Inject delete IKE request
+        mTunUtils.injectPacket(buildInboundPkt(localRemotePorts, deleteIkeReq));
+        mTunUtils.awaitResp(
+                newIkeDeterministicInitSpi, expectedRespMsgId++, true /* expectedUseEncap */);
+
+        verifyDeleteIpSecTransformPair(
+                mFirstChildSessionCallback, firstTransformRecordA, firstTransformRecordB);
+        mFirstChildSessionCallback.awaitOnClosed();
+        mIkeSessionCallback.awaitOnClosed();
+    }
+
+    @Test
+    public void testRekeyTransportModeChildSa() throws Exception {
+        final String ikeInitResp =
+                "46B8ECA1E0D72A18CECD871146CF83A121202220000000000000015022000030"
+                        + "0000002C010100040300000C0100000C800E0100030000080300000C03000008"
+                        + "0200000500000008040000022800008800020000C4904458957746BCF1C12972"
+                        + "1D4E19EB8A584F78DE673053396D167CE0F34552DBC69BA63FE7C673B4CF4A99"
+                        + "62481518EE985357876E8C47BAAA0DBE9C40AE47B12E52165874703586E8F786"
+                        + "045F72EEEB238C5D1823352BED44B71B3214609276ADC0B3D42DAC820168C4E2"
+                        + "660730DAAC92492403288805EBB9053F1AB060DA290000242D9364ACB93519FF"
+                        + "8F8B019BAA43A40D699F59714B327B8382216EF427ED52282900001C00004004"
+                        + "06D91438A0D6B734E152F76F5CC55A72A2E38A0A2900001C000040052EFF78B3"
+                        + "55B37F3CE75AFF26C721B050F892C0D6290000080000402E290000100000402F"
+                        + "00020003000400050000000800004014";
+        final String ikeAuthResp =
+                "46B8ECA1E0D72A18CECD871146CF83A12E20232000000001000000F0240000D4"
+                        + "A17BC258BA2714CF536663639DD5F665A60C75E93557CD5141990A8CEEDD2017"
+                        + "93F5B181C8569FBCD6C2A00198EC2B62D42BEFAC016B8B6BF6A7BC9CEDE3413A"
+                        + "6C495A6B8EC941864DC3E08F57D015EA6520C4B05884960B85478FCA53DA5F17"
+                        + "9628BB1097DA77461C71837207A9EB80720B3E6E661816EE4E14AC995B5E8441"
+                        + "A4C3F9097CC148142BA300076C94A23EC4ADE82B1DD2B121F7E9102860A8C3BF"
+                        + "58DDC207285A3176E924C44DE820322524E1AA438EFDFBA781B36084AED80846"
+                        + "3B77FCED9682B6E4E476408EF3F1037E";
+        final String rekeyChildCreateReq =
+                "46B8ECA1E0D72A18CECD871146CF83A12E202400000000000000015029000134"
+                        + "319D74B6B155B86942143CEC1D29D21F073F24B7BEDC9BFE0F0FDD8BDB5458C0"
+                        + "8DB93506E1A43DD0640FE7370C97F9B34FF4EC9B2DB7257A87B75632301FB68A"
+                        + "86B54871249534CA3D01C9BEB127B669F46470E1C8AAF72574C3CEEC15B901CF"
+                        + "5A0D6ADAE59C3CA64AC8C86689C860FAF9500E608DFE63F2DCD30510FD6FFCD5"
+                        + "A50838574132FD1D069BCACD4C7BAF45C9B1A7689FAD132E3F56DBCFAF905A8C"
+                        + "4145D4BA1B74A54762F8F43308D94DE05649C49D885121CE30681D51AC1E3E68"
+                        + "AB82F9A19B99579AFE257F32DBD1037814DA577379E4F42DEDAC84502E49C933"
+                        + "9EA83F6F5DB4401B660CB1681B023B8603D205DFDD1DE86AD8DE22B6B754F30D"
+                        + "05EAE81A709C2CEE81386133DC3DC7B5EF8F166E48E54A0722DD0C64F4D00638"
+                        + "40F272144C47F6ECED72A248180645DB";
+        final String rekeyChildDeleteReq =
+                "46B8ECA1E0D72A18CECD871146CF83A12E20250000000001000000502A000034"
+                        + "02D98DAF0432EBD991CA4F2D89C1E0EFABC6E91A3327A85D8914FB2F1485BE1B"
+                        + "8D3415D548F7CE0DC4224E7E9D0D3355";
+        final String deleteIkeReq =
+                "46B8ECA1E0D72A18CECD871146CF83A12E20250000000002000000502A000034"
+                        + "095041F4026B4634F04B0AB4F9349484F7BE9AEF03E3733EEE293330043B75D2"
+                        + "ABF5F965ED51127629585E1B1BBA787F";
+
+        // Open IKE Session
+        IkeSession ikeSession = openIkeSessionWithRemoteAddress(mRemoteAddress);
+        PortPair localRemotePorts = performSetupIkeAndFirstChildBlocking(ikeInitResp, ikeAuthResp);
+
+        // IKE INIT and IKE AUTH takes two exchanges. Local request message ID starts from 2
+        int expectedReqMsgId = 2;
+        int expectedRespMsgId = 0;
+
+        verifyIkeSessionSetupBlocking();
+        verifyChildSessionSetupBlocking(
+                mFirstChildSessionCallback,
+                Arrays.asList(TRANSPORT_MODE_INBOUND_TS),
+                Arrays.asList(TRANSPORT_MODE_OUTBOUND_TS),
+                new ArrayList<LinkAddress>());
+        IpSecTransformCallRecord oldTransformRecordA =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        IpSecTransformCallRecord oldTransformRecordB =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        verifyCreateIpSecTransformPair(oldTransformRecordA, oldTransformRecordB);
+
+        // Inject rekey Child requests
+        mTunUtils.injectPacket(buildInboundPkt(localRemotePorts, rekeyChildCreateReq));
+        mTunUtils.awaitResp(
+                IKE_DETERMINISTIC_INITIATOR_SPI, expectedRespMsgId++, true /* expectedUseEncap */);
+        mTunUtils.injectPacket(buildInboundPkt(localRemotePorts, rekeyChildDeleteReq));
+        mTunUtils.awaitResp(
+                IKE_DETERMINISTIC_INITIATOR_SPI, expectedRespMsgId++, true /* expectedUseEncap */);
+
+        // Verify IpSecTransforms are renewed
+        IpSecTransformCallRecord newTransformRecordA =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        IpSecTransformCallRecord newTransformRecordB =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        verifyCreateIpSecTransformPair(newTransformRecordA, newTransformRecordB);
+        verifyDeleteIpSecTransformPair(
+                mFirstChildSessionCallback, oldTransformRecordA, oldTransformRecordB);
+
+        // Inject delete IKE request
+        mTunUtils.injectPacket(buildInboundPkt(localRemotePorts, deleteIkeReq));
+        mTunUtils.awaitResp(
+                IKE_DETERMINISTIC_INITIATOR_SPI, expectedRespMsgId++, true /* expectedUseEncap */);
+
+        verifyDeleteIpSecTransformPair(
+                mFirstChildSessionCallback, newTransformRecordA, newTransformRecordB);
+        mFirstChildSessionCallback.awaitOnClosed();
+        mIkeSessionCallback.awaitOnClosed();
+    }
+}
diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java
index 86e5c48..0f39fbd 100644
--- a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java
@@ -44,6 +44,7 @@
 import android.net.ipsec.ike.IkeTrafficSelector;
 import android.net.ipsec.ike.TransportModeChildSessionParams;
 import android.net.ipsec.ike.TunnelModeChildSessionParams;
+import android.net.ipsec.ike.cts.IkeTunUtils.PortPair;
 import android.net.ipsec.ike.cts.TestNetworkUtils.TestNetworkCallback;
 import android.net.ipsec.ike.exceptions.IkeException;
 import android.net.ipsec.ike.exceptions.IkeProtocolException;
@@ -269,13 +270,13 @@
                 .build();
     }
 
-    void performSetupIkeAndFirstChildBlocking(String ikeInitRespHex, String... ikeAuthRespHexes)
+    PortPair performSetupIkeAndFirstChildBlocking(String ikeInitRespHex, String... ikeAuthRespHexes)
             throws Exception {
-        performSetupIkeAndFirstChildBlocking(
+        return performSetupIkeAndFirstChildBlocking(
                 ikeInitRespHex, 1 /* expectedAuthReqPktCnt */, ikeAuthRespHexes);
     }
 
-    void performSetupIkeAndFirstChildBlocking(
+    PortPair performSetupIkeAndFirstChildBlocking(
             String ikeInitRespHex, int expectedAuthReqPktCnt, String... ikeAuthRespHexes)
             throws Exception {
         mTunUtils.awaitReqAndInjectResp(
@@ -284,12 +285,16 @@
                 false /* expectedUseEncap */,
                 ikeInitRespHex);
 
-        mTunUtils.awaitReqAndInjectResp(
-                IKE_DETERMINISTIC_INITIATOR_SPI,
-                1 /* expectedMsgId */,
-                true /* expectedUseEncap */,
-                expectedAuthReqPktCnt,
-                ikeAuthRespHexes);
+        byte[] ikeAuthReqPkt =
+                mTunUtils
+                        .awaitReqAndInjectResp(
+                                IKE_DETERMINISTIC_INITIATOR_SPI,
+                                1 /* expectedMsgId */,
+                                true /* expectedUseEncap */,
+                                expectedAuthReqPktCnt,
+                                ikeAuthRespHexes)
+                        .get(0);
+        return IkeTunUtils.getSrcDestPortPair(ikeAuthReqPkt);
     }
 
     void performCloseIkeBlocking(int expectedMsgId, String deleteIkeRespHex) throws Exception {
diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java
index c83d5f3..41cbf0b 100644
--- a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java
@@ -55,6 +55,8 @@
     private static final int IKE_FRAG_NUM_OFFSET = 32;
     private static final int IKE_PAYLOAD_TYPE_SKF = 53;
 
+    private static final int RSP_FLAG_MASK = 0x20;
+
     public IkeTunUtils(ParcelFileDescriptor tunFd) {
         super(tunFd);
     }
@@ -136,8 +138,7 @@
         InetAddress dstAddr = getAddress(request, true /* shouldGetSource */);
         int srcPort = getPort(request, false /* shouldGetSource */);
         int dstPort = getPort(request, true /* shouldGetSource */);
-
-        for (String hex : ikeRespDataFragmentsHex) {
+        for (String resp : ikeRespDataFragmentsHex) {
             byte[] response =
                     buildIkePacket(
                             srcAddr,
@@ -145,13 +146,27 @@
                             srcPort,
                             dstPort,
                             expectedUseEncap,
-                            hexStringToByteArray(hex));
+                            hexStringToByteArray(resp));
             injectPacket(response);
         }
 
         return reqList;
     }
 
+    /** Await the expected IKE response */
+    public byte[] awaitResp(long expectedInitIkeSpi, int expectedMsgId, boolean expectedUseEncap)
+            throws Exception {
+        return awaitIkePacket(
+                (pkt) -> {
+                    return isExpectedIkePkt(
+                            pkt,
+                            expectedInitIkeSpi,
+                            expectedMsgId,
+                            true /* expectedResp*/,
+                            expectedUseEncap);
+                });
+    }
+
     private byte[] awaitIkePacket(Predicate<byte[]> pktVerifier) throws Exception {
         long endTime = System.currentTimeMillis() + TIMEOUT;
         int startIndex = 0;
@@ -239,13 +254,36 @@
 
         ByteBuffer buffer = ByteBuffer.wrap(pkt);
         buffer.get(new byte[ikeOffset]); // Skip IP, UDP header (and NON_ESP_MARKER)
+        buffer.mark(); // Mark this position so that later we can reset back here
 
-        // Check message ID.
+        // Check SPI
+        buffer.get(new byte[IKE_INIT_SPI_OFFSET]);
+        long initSpi = buffer.getLong();
+        if (expectedInitIkeSpi != initSpi) {
+            return false;
+        }
+
+        // Check direction
+        buffer.reset();
+        buffer.get(new byte[IKE_IS_RESP_BYTE_OFFSET]);
+        byte flagsByte = buffer.get();
+        boolean isResp = ((flagsByte & RSP_FLAG_MASK) != 0);
+        if (expectedResp != isResp) {
+            return false;
+        }
+
+        // Check message ID
+        buffer.reset();
         buffer.get(new byte[IKE_MSG_ID_OFFSET]);
-        int msgId = buffer.getInt();
-        return expectedMsgId == msgId;
 
-        // TODO: Check SPI and packet direction
+        // Both the expected message ID and the packet's msgId are signed integers, so directly
+        // compare them.
+        int msgId = buffer.getInt();
+        if (expectedMsgId != msgId) {
+            return false;
+        }
+
+        return true;
     }
 
     private static boolean isExpectedFragNum(byte[] pkt, int ikeOffset, int expectedFragNum) {
@@ -267,6 +305,22 @@
         return expectedFragNum == fragNum;
     }
 
+    public static class PortPair {
+        public final int srcPort;
+        public final int dstPort;
+
+        public PortPair(int sourcePort, int destinationPort) {
+            srcPort = sourcePort;
+            dstPort = destinationPort;
+        }
+    }
+
+    public static PortPair getSrcDestPortPair(byte[] outboundIkePkt) throws Exception {
+        return new PortPair(
+                getPort(outboundIkePkt, true /* shouldGetSource */),
+                getPort(outboundIkePkt, false /* shouldGetSource */));
+    }
+
     private static InetAddress getAddress(byte[] pkt, boolean shouldGetSource) throws Exception {
         int ipLen = isIpv6(pkt) ? IP6_ADDR_LEN : IP4_ADDR_LEN;
         int srcIpOffset = isIpv6(pkt) ? IP6_ADDR_OFFSET : IP4_ADDR_OFFSET;
@@ -288,7 +342,7 @@
         return Short.toUnsignedInt(buffer.getShort());
     }
 
-    private static byte[] buildIkePacket(
+    public static byte[] buildIkePacket(
             InetAddress srcAddr,
             InetAddress dstAddr,
             int srcPort,