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Diffstat (limited to 'common/framework/com/android/net/module/util/DnsPacketUtils.java')
-rw-r--r--common/framework/com/android/net/module/util/DnsPacketUtils.java191
1 files changed, 0 insertions, 191 deletions
diff --git a/common/framework/com/android/net/module/util/DnsPacketUtils.java b/common/framework/com/android/net/module/util/DnsPacketUtils.java
deleted file mode 100644
index 105d7837..00000000
--- a/common/framework/com/android/net/module/util/DnsPacketUtils.java
+++ /dev/null
@@ -1,191 +0,0 @@
-/*
- * 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.DnsPacket.DnsRecord.NAME_COMPRESSION;
-import static com.android.net.module.util.DnsPacket.DnsRecord.NAME_NORMAL;
-
-import android.annotation.NonNull;
-import android.annotation.Nullable;
-import android.net.InetAddresses;
-import android.net.ParseException;
-import android.text.TextUtils;
-import android.util.Patterns;
-
-import com.android.internal.annotations.VisibleForTesting;
-
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.nio.BufferUnderflowException;
-import java.nio.ByteBuffer;
-import java.nio.charset.StandardCharsets;
-import java.text.DecimalFormat;
-import java.text.FieldPosition;
-
-/**
- * Utilities for decoding the contents of a DnsPacket.
- *
- * @hide
- */
-public final class DnsPacketUtils {
- /**
- * Reads the passed ByteBuffer from its current position and decodes a DNS record.
- */
- public static class DnsRecordParser {
- private static final int MAXLABELSIZE = 63;
- private static final int MAXNAMESIZE = 255;
- private static final int MAXLABELCOUNT = 128;
-
- private static final DecimalFormat sByteFormat = new DecimalFormat();
- private static final FieldPosition sPos = new FieldPosition(0);
-
- /**
- * Convert label from {@code byte[]} to {@code String}
- *
- * <p>Follows the same conversion rules of the native code (ns_name.c in libc).
- */
- @VisibleForTesting
- static String labelToString(@NonNull byte[] label) {
- final StringBuffer sb = new StringBuffer();
-
- for (int i = 0; i < label.length; ++i) {
- int b = Byte.toUnsignedInt(label[i]);
- // Control characters and non-ASCII characters.
- if (b <= 0x20 || b >= 0x7f) {
- // Append the byte as an escaped decimal number, e.g., "\19" for 0x13.
- sb.append('\\');
- sByteFormat.format(b, sb, sPos);
- } else if (b == '"' || b == '.' || b == ';' || b == '\\' || b == '(' || b == ')'
- || b == '@' || b == '$') {
- // Append the byte as an escaped character, e.g., "\:" for 0x3a.
- sb.append('\\');
- sb.append((char) b);
- } else {
- // Append the byte as a character, e.g., "a" for 0x61.
- sb.append((char) b);
- }
- }
- return sb.toString();
- }
-
- /**
- * Converts domain name to labels according to RFC 1035.
- *
- * @param name Domain name as String that needs to be converted to labels.
- * @return An encoded byte array that is constructed out of labels,
- * and ends with zero-length label.
- * @throws ParseException if failed to parse the given domain name or
- * IOException if failed to output labels.
- */
- public static @NonNull byte[] domainNameToLabels(@NonNull String name) throws
- IOException, ParseException {
- if (name.length() > MAXNAMESIZE) {
- throw new ParseException("Domain name exceeds max length: " + name.length());
- }
- if (!isHostName(name)) {
- throw new ParseException("Failed to parse domain name: " + name);
- }
- final ByteArrayOutputStream buf = new ByteArrayOutputStream();
- final String[] labels = name.split("\\.");
- for (final String label : labels) {
- if (label.length() > MAXLABELSIZE) {
- throw new ParseException("label is too long: " + label);
- }
- buf.write(label.length());
- // Encode as UTF-8 as suggested in RFC 6055 section 3.
- buf.write(label.getBytes(StandardCharsets.UTF_8));
- }
- buf.write(0x00); // end with zero-length label
- return buf.toByteArray();
- }
-
- /**
- * Check whether the input is a valid hostname based on rfc 1035 section 3.3.
- *
- * @param hostName the target host name.
- * @return true if the input is a valid hostname.
- */
- public static boolean isHostName(@Nullable String hostName) {
- // TODO: Use {@code Patterns.HOST_NAME} if available.
- // Patterns.DOMAIN_NAME accepts host names or IP addresses, so reject
- // IP addresses.
- return hostName != null
- && Patterns.DOMAIN_NAME.matcher(hostName).matches()
- && !InetAddresses.isNumericAddress(hostName);
- }
-
- /**
- * Parses the domain / target name of a DNS record.
- */
- public static String parseName(final ByteBuffer buf, int depth,
- boolean isNameCompressionSupported) throws
- BufferUnderflowException, DnsPacket.ParseException {
- return parseName(buf, depth, MAXLABELCOUNT, isNameCompressionSupported);
- }
-
- /**
- * Parses the domain / target name of a DNS record.
- *
- * As described in RFC 1035 Section 4.1.3, the NAME field of a DNS Resource Record always
- * supports Name Compression, whereas domain names contained in the RDATA payload of a DNS
- * record may or may not support Name Compression, depending on the record TYPE. Moreover,
- * even if Name Compression is supported, its usage is left to the implementation.
- */
- public static String parseName(final ByteBuffer buf, int depth, int maxLabelCount,
- boolean isNameCompressionSupported) throws
- BufferUnderflowException, DnsPacket.ParseException {
- if (depth > maxLabelCount) {
- throw new DnsPacket.ParseException("Failed to parse name, too many labels");
- }
- final int len = Byte.toUnsignedInt(buf.get());
- final int mask = len & NAME_COMPRESSION;
- if (0 == len) {
- return "";
- } else if (mask != NAME_NORMAL && mask != NAME_COMPRESSION
- || (!isNameCompressionSupported && mask == NAME_COMPRESSION)) {
- throw new DnsPacket.ParseException("Parse name fail, bad label type: " + mask);
- } else if (mask == NAME_COMPRESSION) {
- // Name compression based on RFC 1035 - 4.1.4 Message compression
- final int offset = ((len & ~NAME_COMPRESSION) << 8) + Byte.toUnsignedInt(buf.get());
- final int oldPos = buf.position();
- if (offset >= oldPos - 2) {
- throw new DnsPacket.ParseException(
- "Parse compression name fail, invalid compression");
- }
- buf.position(offset);
- final String pointed = parseName(buf, depth + 1, maxLabelCount,
- isNameCompressionSupported);
- buf.position(oldPos);
- return pointed;
- } else {
- final byte[] label = new byte[len];
- buf.get(label);
- final String head = labelToString(label);
- if (head.length() > MAXLABELSIZE) {
- throw new DnsPacket.ParseException("Parse name fail, invalid label length");
- }
- final String tail = parseName(buf, depth + 1, maxLabelCount,
- isNameCompressionSupported);
- return TextUtils.isEmpty(tail) ? head : head + "." + tail;
- }
- }
-
- private DnsRecordParser() {}
- }
-
- private DnsPacketUtils() {}
-}
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