diff options
Diffstat (limited to 'common/device/com/android/net/module/util/DomainUtils.java')
| -rw-r--r-- | common/device/com/android/net/module/util/DomainUtils.java | 143 |
1 files changed, 0 insertions, 143 deletions
diff --git a/common/device/com/android/net/module/util/DomainUtils.java b/common/device/com/android/net/module/util/DomainUtils.java deleted file mode 100644 index b327fd08..00000000 --- a/common/device/com/android/net/module/util/DomainUtils.java +++ /dev/null @@ -1,143 +0,0 @@ -/* - * Copyright (C) 2023 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 android.util.ArrayMap; -import android.util.Log; - -import androidx.annotation.NonNull; -import androidx.annotation.Nullable; - -import com.android.net.module.util.DnsPacketUtils.DnsRecordParser; - -import java.nio.BufferOverflowException; -import java.nio.BufferUnderflowException; -import java.nio.ByteBuffer; -import java.nio.charset.StandardCharsets; -import java.util.ArrayList; - -/** - * Utilities for encoding/decoding the domain name or domain search list. - * - * @hide - */ -public final class DomainUtils { - private static final String TAG = "DomainUtils"; - private static final int MAX_OPTION_LEN = 255; - - @NonNull - private static String getSubstring(@NonNull final String string, @NonNull final String[] labels, - int index) { - int beginIndex = 0; - for (int i = 0; i < index; i++) { - beginIndex += labels[i].length() + 1; // include the dot - } - return string.substring(beginIndex); - } - - /** - * Encode the given single domain name to byte array, comply with RFC1035 section-3.1. - * - * @return null if the given domain string is invalid, otherwise, return a byte array - * wrapping the encoded domain, not including any padded octets, caller should - * pad zero octets at the end if needed. - */ - @Nullable - public static byte[] encode(@NonNull final String domain) { - if (!DnsRecordParser.isHostName(domain)) return null; - return encode(new String[]{ domain }, false /* compression */); - } - - /** - * Encode the given multiple domain names to byte array, comply with RFC1035 section-3.1 - * and section 4.1.4 (message compression) if enabled. - * - * @return Null if encode fails due to BufferOverflowException, otherwise, return a byte - * array wrapping the encoded domains, not including any padded octets, caller - * should pad zero octets at the end if needed. The byte array may be empty if - * the given domain strings are invalid. - */ - @Nullable - public static byte[] encode(@NonNull final String[] domains, boolean compression) { - try { - final ByteBuffer buffer = ByteBuffer.allocate(MAX_OPTION_LEN); - final ArrayMap<String, Integer> offsetMap = new ArrayMap<>(); - for (int i = 0; i < domains.length; i++) { - if (!DnsRecordParser.isHostName(domains[i])) { - Log.e(TAG, "Skip invalid domain name " + domains[i]); - continue; - } - final String[] labels = domains[i].split("\\."); - for (int j = 0; j < labels.length; j++) { - if (compression) { - final String suffix = getSubstring(domains[i], labels, j); - if (offsetMap.containsKey(suffix)) { - int offsetOfSuffix = offsetMap.get(suffix); - offsetOfSuffix |= 0xC000; - buffer.putShort((short) offsetOfSuffix); - break; // unnecessary to put the compressed string into map - } else { - offsetMap.put(suffix, buffer.position()); - } - } - // encode the domain name string without compression when: - // - compression feature isn't enabled, - // - suffix does not match any string in the map. - final byte[] labelBytes = labels[j].getBytes(StandardCharsets.UTF_8); - buffer.put((byte) labelBytes.length); - buffer.put(labelBytes); - if (j == labels.length - 1) { - // Pad terminate label at the end of last label. - buffer.put((byte) 0); - } - } - } - buffer.flip(); - final byte[] out = new byte[buffer.limit()]; - buffer.get(out); - return out; - } catch (BufferOverflowException e) { - Log.e(TAG, "Fail to encode domain name and stop encoding", e); - return null; - } - } - - /** - * Decode domain name(s) from the given byteBuffer. Decode follows RFC1035 section 3.1 and - * section 4.1.4(message compression). - * - * @return domain name(s) string array with space separated, or empty string if decode fails. - */ - @NonNull - public static ArrayList<String> decode(@NonNull final ByteBuffer buffer, boolean compression) { - final ArrayList<String> domainList = new ArrayList<>(); - while (buffer.remaining() > 0) { - try { - // TODO: replace the recursion with loop in parseName and don't need to pass in the - // maxLabelCount parameter to prevent recursion from overflowing stack. - final String domain = DnsRecordParser.parseName(buffer, 0 /* depth */, - 15 /* maxLabelCount */, compression); - if (!DnsRecordParser.isHostName(domain)) continue; - domainList.add(domain); - } catch (BufferUnderflowException | DnsPacket.ParseException e) { - Log.e(TAG, "Fail to parse domain name and stop parsing", e); - break; - } - } - return domainList; - } -} |