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/*
* Copyright (C) 2019 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 static com.android.net.module.util.DnsPacketUtils.DnsRecordParser;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThrows;
import android.net.ParseException;
import android.os.Build;
import androidx.test.filters.SmallTest;
import androidx.test.runner.AndroidJUnit4;
import com.android.testutils.DevSdkIgnoreRule;
import org.junit.Assert;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import java.nio.ByteBuffer;
@RunWith(AndroidJUnit4.class)
@SmallTest
public class DnsPacketUtilsTest {
@Rule
public final DevSdkIgnoreRule mIgnoreRule = new DevSdkIgnoreRule();
/**
* Verifies that the compressed NAME field in the answer section of the DNS message is parsed
* successfully when name compression is permitted. Additionally, verifies that a
* {@link DnsPacket.ParseException} is thrown in a hypothetical scenario where name compression
* is not expected.
*/
@Test
public void testParsingAnswerSectionNameCompressed() throws Exception {
final byte[] v4blobNameCompressedAnswer = new byte[] {
/* Header */
0x55, 0x66, /* Transaction ID */
(byte) 0x81, (byte) 0x80, /* Flags */
0x00, 0x01, /* Questions */
0x00, 0x01, /* Answer RRs */
0x00, 0x00, /* Authority RRs */
0x00, 0x00, /* Additional RRs */
/* Queries */
0x03, 0x77, 0x77, 0x77, 0x06, 0x67, 0x6F, 0x6F, 0x67, 0x6c, 0x65,
0x03, 0x63, 0x6f, 0x6d, 0x00, /* Name */
0x00, 0x01, /* Type */
0x00, 0x01, /* Class */
/* Answers */
(byte) 0xc0, 0x0c, /* Name */
0x00, 0x01, /* Type */
0x00, 0x01, /* Class */
0x00, 0x00, 0x01, 0x2b, /* TTL */
0x00, 0x04, /* Data length */
(byte) 0xac, (byte) 0xd9, (byte) 0xa1, (byte) 0x84 /* Address */
};
final int answerOffsetBytePosition = 32;
final ByteBuffer nameCompressedBuf = ByteBuffer.wrap(v4blobNameCompressedAnswer);
nameCompressedBuf.position(answerOffsetBytePosition);
assertThrows(DnsPacket.ParseException.class, () -> DnsRecordParser.parseName(
nameCompressedBuf, /* depth= */ 0, /* isNameCompressionSupported= */false));
nameCompressedBuf.position(answerOffsetBytePosition);
String domainName = DnsRecordParser.parseName(
nameCompressedBuf, /* depth= */ 0, /* isNameCompressionSupported= */true);
assertEquals(domainName, "www.google.com");
}
/**
* Verifies that an uncompressed NAME field in the answer section of the DNS message is parsed
* successfully irrespective of whether name compression is permitted.
*/
@Test
public void testParsingAnswerSectionNoNameCompression() throws Exception {
final byte[] v4blobNoNameCompression = new byte[] {
/* Header */
0x55, 0x66, /* Transaction ID */
(byte) 0x81, (byte) 0x80, /* Flags */
0x00, 0x01, /* Questions */
0x00, 0x01, /* Answer RRs */
0x00, 0x00, /* Authority RRs */
0x00, 0x00, /* Additional RRs */
/* Queries */
0x03, 0x77, 0x77, 0x77, 0x06, 0x67, 0x6F, 0x6F, 0x67, 0x6c, 0x65,
0x03, 0x63, 0x6f, 0x6d, 0x00, /* Name */
0x00, 0x01, /* Type */
0x00, 0x01, /* Class */
/* Answers */
0x03, 0x77, 0x77, 0x77, 0x06, 0x67, 0x6F, 0x6F, 0x67, 0x6c, 0x65,
0x03, 0x63, 0x6f, 0x6d, 0x00, /* Name */
0x00, 0x01, /* Type */
0x00, 0x01, /* Class */
0x00, 0x00, 0x01, 0x2b, /* TTL */
0x00, 0x04, /* Data length */
(byte) 0xac, (byte) 0xd9, (byte) 0xa1, (byte) 0x84 /* Address */
};
final int answerOffsetBytePosition = 32;
final ByteBuffer notNameCompressedBuf = ByteBuffer.wrap(v4blobNoNameCompression);
notNameCompressedBuf.position(answerOffsetBytePosition);
String domainName = DnsRecordParser.parseName(
notNameCompressedBuf, /* depth= */ 0, /* isNameCompressionSupported= */ true);
assertEquals(domainName, "www.google.com");
notNameCompressedBuf.position(answerOffsetBytePosition);
domainName = DnsRecordParser.parseName(
notNameCompressedBuf, /* depth= */ 0, /* isNameCompressionSupported= */ false);
assertEquals(domainName, "www.google.com");
}
// Skip test on R- devices since ParseException only available on S+ devices.
@DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.R)
@Test
public void testDomainNameToLabels() throws Exception {
assertArrayEquals(
new byte[]{3, 'w', 'w', 'w', 6, 'g', 'o', 'o', 'g', 'l', 'e', 3, 'c', 'o', 'm', 0},
DnsRecordParser.domainNameToLabels("www.google.com"));
assertThrows(ParseException.class, () ->
DnsRecordParser.domainNameToLabels("aaa."));
assertThrows(ParseException.class, () ->
DnsRecordParser.domainNameToLabels("aaa"));
assertThrows(ParseException.class, () ->
DnsRecordParser.domainNameToLabels("."));
assertThrows(ParseException.class, () ->
DnsRecordParser.domainNameToLabels(""));
}
@Test
public void testIsHostName() {
Assert.assertTrue(DnsRecordParser.isHostName("www.google.com"));
Assert.assertFalse(DnsRecordParser.isHostName("com"));
Assert.assertFalse(DnsRecordParser.isHostName("1.2.3.4"));
Assert.assertFalse(DnsRecordParser.isHostName("1234::5678"));
Assert.assertFalse(DnsRecordParser.isHostName(null));
Assert.assertFalse(DnsRecordParser.isHostName(""));
}
}
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