Encode IKE header

This commit:
- Add method for encoding IKE header
- Create IkeHeaderTest

Bug: 116149910
Test: FrameworksIkeTests IkeIkeHeaderTest
Change-Id: Ib5507330183184583a0e82296694dad2e68e9e17

3 files changed, 125 insertions, 41 deletions

diff --git a/src/java/com/android/ike/ikev2/message/IkeHeader.java b/src/java/com/android/ike/ikev2/message/IkeHeader.java
index 7aa76b25..cd415163 100644
--- a/src/java/com/android/ike/ikev2/message/IkeHeader.java
+++ b/src/java/com/android/ike/ikev2/message/IkeHeader.java
@@ -36,6 +36,13 @@ import java.nio.ByteBuffer;
  *     Protocol Version 2 (IKEv2).
  */
 public final class IkeHeader {
+    private static final byte IKE_HEADER_VERSION_INFO = (byte) 0x20;
+
+    // Indicate whether this message is a response message
+    private static final byte IKE_HEADER_FLAG_IS_RESP_MSG = (byte) 0x20;
+    // Indicate whether this message is sent from the original IKE initiator
+    private static final byte IKE_HEADER_FLAG_FROM_IKE_INITIATOR = (byte) 0x08;
+
     public static final int IKE_HEADER_LENGTH = 28;
 
     @Retention(RetentionPolicy.SOURCE)
@@ -58,7 +65,7 @@ public final class IkeHeader {
     public final byte majorVersion;
     public final byte minorVersion;
     @ExchangeType public final int exchangeType;
-    public final boolean isResponse;
+    public final boolean isResponseMsg;
     public final boolean fromIkeInitiator;
     public final int messageId;
     public final int messageLength;
@@ -89,7 +96,7 @@ public final class IkeHeader {
         ikeResponderSpi = rSpi;
         nextPayloadType = nextPType;
         exchangeType = eType;
-        isResponse = isResp;
+        isResponseMsg = isResp;
         fromIkeInitiator = fromInit;
         messageId = msgId;
         messageLength = length;
@@ -123,7 +130,7 @@ public final class IkeHeader {
         exchangeType = Byte.toUnsignedInt(buffer.get());
 
         byte flagsByte = buffer.get();
-        isResponse = ((flagsByte & 0x20) != 0);
+        isResponseMsg = ((flagsByte & 0x20) != 0);
         fromIkeInitiator = ((flagsByte & 0x08) != 0);
 
         messageId = buffer.getInt();
@@ -148,4 +155,24 @@ public final class IkeHeader {
             throw new InvalidSyntaxException("Invalid IKE Exchange Type.");
         }
     }
+
+    /** Encode IKE header to ByteBuffer */
+    public void encodeToByteBuffer(ByteBuffer byteBuffer) {
+        byteBuffer
+                .putLong(ikeInitiatorSpi)
+                .putLong(ikeResponderSpi)
+                .put((byte) nextPayloadType)
+                .put(IKE_HEADER_VERSION_INFO)
+                .put((byte) exchangeType);
+
+        byte flag = 0;
+        if (isResponseMsg) {
+            flag |= IKE_HEADER_FLAG_IS_RESP_MSG;
+        }
+        if (fromIkeInitiator) {
+            flag |= IKE_HEADER_FLAG_FROM_IKE_INITIATOR;
+        }
+
+        byteBuffer.put(flag).putInt(messageId).putInt(messageLength);
+    }
 }
diff --git a/tests/iketests/src/java/com/android/ike/ikev2/message/IkeHeaderTest.java b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeHeaderTest.java
new file mode 100644
index 00000000..fd4ca910
--- /dev/null
+++ b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeHeaderTest.java
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2018 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.ike.ikev2.message;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import java.nio.ByteBuffer;
+
+public final class IkeHeaderTest {
+    private static final String IKE_HEADER_HEX_STRING =
+            "8f54bf6d8b48e6e10000000000000000212022080000000000000150";
+    private static final String IKE_SA_INIT_RAW_PACKET =
+            "8f54bf6d8b48e6e100000000000000002120220800000000"
+                    + "00000150220000300000002c010100040300000c0100000c"
+                    + "800e00800300000803000002030000080400000200000008"
+                    + "020000022800008800020000b4a2faf4bb54878ae21d6385"
+                    + "12ece55d9236fc5046ab6cef82220f421f3ce6361faf3656"
+                    + "4ecb6d28798a94aad7b2b4b603ddeaaa5630adb9ece8ac37"
+                    + "534036040610ebdd92f46bef84f0be7db860351843858f8a"
+                    + "cf87056e272377f70c9f2d81e29c7b0ce4f291a3a72476bb"
+                    + "0b278fd4b7b0a4c26bbeb08214c707137607958729000024"
+                    + "c39b7f368f4681b89fa9b7be6465abd7c5f68b6ed5d3b4c7"
+                    + "2cb4240eb5c464122900001c00004004e54f73b7d83f6beb"
+                    + "881eab2051d8663f421d10b02b00001c00004005d915368c"
+                    + "a036004cb578ae3e3fb268509aeab1900000002069936922"
+                    + "8741c6d4ca094c93e242c9de19e7b7c60000000500000500";
+
+    private static final String IKE_INITIATOR_SPI = "8f54bf6d8b48e6e1";
+    private static final String IKE_RESPODNER_SPI = "0000000000000000";
+
+    @IkePayload.PayloadType
+    private static final byte IKE_FIRST_PAYLOAD_TYPE = IkePayload.PAYLOAD_TYPE_SA;
+
+    private static final byte IKE_MAJOR_VERSION = 2;
+    private static final byte IKE_MINOR_VERSION = 0;
+
+    @IkeHeader.ExchangeType
+    private static final int IKE_EXCHANGE_TYPE = IkeHeader.EXCHANGE_TYPE_IKE_INIT_SA;
+
+    private static final int IKE_MSG_ID = 0;
+    private static final int IKE_MSG_LENGTH = 336;
+
+    @Test
+    public void testDecodeIkeHeader() throws Exception {
+        byte[] inputPacket = TestUtils.hexStringToByteArray(IKE_SA_INIT_RAW_PACKET);
+        IkeHeader header = new IkeHeader(inputPacket);
+
+        assertEquals(IKE_MSG_LENGTH, inputPacket.length);
+
+        long initSpi = Long.parseUnsignedLong(IKE_INITIATOR_SPI, 16);
+        assertEquals(initSpi, header.ikeInitiatorSpi);
+        long respSpi = Long.parseUnsignedLong(IKE_RESPODNER_SPI, 16);
+        assertEquals(respSpi, header.ikeResponderSpi);
+
+        assertEquals(IKE_FIRST_PAYLOAD_TYPE, header.nextPayloadType);
+        assertEquals(IKE_MAJOR_VERSION, header.majorVersion);
+        assertEquals(IKE_MINOR_VERSION, header.minorVersion);
+        assertEquals(IKE_EXCHANGE_TYPE, header.exchangeType);
+        assertFalse(header.isResponseMsg);
+        assertTrue(header.fromIkeInitiator);
+        assertEquals(IKE_MSG_ID, header.messageId);
+        assertEquals(IKE_MSG_LENGTH, header.messageLength);
+    }
+
+    @Test
+    public void testEncodeIkeHeader() throws Exception {
+        byte[] inputPacket = TestUtils.hexStringToByteArray(IKE_SA_INIT_RAW_PACKET);
+        IkeHeader header = new IkeHeader(inputPacket);
+
+        ByteBuffer byteBuffer = ByteBuffer.allocate(IkeHeader.IKE_HEADER_LENGTH);
+        header.encodeToByteBuffer(byteBuffer);
+
+        byte[] expectedPacket = TestUtils.hexStringToByteArray(IKE_HEADER_HEX_STRING);
+        assertArrayEquals(expectedPacket, byteBuffer.array());
+    }
+}
diff --git a/tests/iketests/src/java/com/android/ike/ikev2/message/IkeMessageTest.java b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeMessageTest.java
index 05c59607..8978f688 100644
--- a/tests/iketests/src/java/com/android/ike/ikev2/message/IkeMessageTest.java
+++ b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeMessageTest.java
@@ -17,8 +17,6 @@
 package com.android.ike.ikev2.message;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import com.android.ike.ikev2.exceptions.IkeException;
@@ -47,20 +45,6 @@ public final class IkeMessageTest {
                     + "881eab2051d8663f421d10b02b00001c00004005d915368c"
                     + "a036004cb578ae3e3fb268509aeab1900000002069936922"
                     + "8741c6d4ca094c93e242c9de19e7b7c60000000500000500";
-    private static final String IKE_INITIATOR_SPI = "8f54bf6d8b48e6e1";
-    private static final String IKE_RESPODNER_SPI = "0000000000000000";
-
-    @IkePayload.PayloadType
-    private static final byte IKE_FIRST_PAYLOAD_TYPE = IkePayload.PAYLOAD_TYPE_SA;
-
-    private static final byte IKE_MAJOR_VERSION = 2;
-    private static final byte IKE_MINOR_VERSION = 0;
-
-    @IkeHeader.ExchangeType
-    private static final int IKE_EXCHANGE_TYPE = IkeHeader.EXCHANGE_TYPE_IKE_INIT_SA;
-
-    private static final int IKE_MSG_ID = 0;
-    private static final int IKE_MSG_LENGTH = 336;
 
     private static final int FIRST_PAYLOAD_TYPE_POSITION = 16;
     private static final int VERSION_POSITION = 17;
@@ -118,28 +102,6 @@ public final class IkeMessageTest {
     }
 
     @Test
-    public void testDecodeIkeHeader() throws Exception {
-        byte[] inputPacket = TestUtils.hexStringToByteArray(IKE_SA_INIT_RAW_PACKET);
-        IkeHeader header = new IkeHeader(inputPacket);
-
-        assertEquals(IKE_MSG_LENGTH, inputPacket.length);
-
-        long initSpi = Long.parseUnsignedLong(IKE_INITIATOR_SPI, 16);
-        assertEquals(initSpi, header.ikeInitiatorSpi);
-        long respSpi = Long.parseUnsignedLong(IKE_RESPODNER_SPI, 16);
-        assertEquals(respSpi, header.ikeResponderSpi);
-
-        assertEquals(IKE_FIRST_PAYLOAD_TYPE, header.nextPayloadType);
-        assertEquals(IKE_MAJOR_VERSION, header.majorVersion);
-        assertEquals(IKE_MINOR_VERSION, header.minorVersion);
-        assertEquals(IKE_EXCHANGE_TYPE, header.exchangeType);
-        assertFalse(header.isResponse);
-        assertTrue(header.fromIkeInitiator);
-        assertEquals(IKE_MSG_ID, header.messageId);
-        assertEquals(IKE_MSG_LENGTH, header.messageLength);
-    }
-
-    @Test
     public void testDecodeIkeMessage() throws Exception {
         byte[] inputPacket = TestUtils.hexStringToByteArray(IKE_SA_INIT_RAW_PACKET);
         IkeHeader header = new IkeHeader(inputPacket);