From 0331db1c2c3bc6cb0078fac65e64d76a5b30b74f Mon Sep 17 00:00:00 2001 From: Aaron Huang Date: Mon, 6 Jan 2020 20:01:12 +0800 Subject: [PATCH] Add DnsSdTxtRecord to common net static library Move DnsSdTxtRecord from framework to net-utils-framework-common for mainline support. Bug: 139268426 Bug: 135998869 Test: build lib pass atest FrameworksNetTests ./frameworks/opt/net/wifi/tests/wifitests/runtests.sh Merged-In: I16c37b1c0b70bd57f38bde1171bd7d84cf3fa9ce Change-Id: I16c37b1c0b70bd57f38bde1171bd7d84cf3fa9ce (clean cherry-pick from internal branch) --- .../android/net/util/nsd/DnsSdTxtRecord.java | 325 ++++++++++++++++++ 1 file changed, 325 insertions(+) create mode 100644 staticlibs/src_frameworkcommon/android/net/util/nsd/DnsSdTxtRecord.java diff --git a/staticlibs/src_frameworkcommon/android/net/util/nsd/DnsSdTxtRecord.java b/staticlibs/src_frameworkcommon/android/net/util/nsd/DnsSdTxtRecord.java new file mode 100644 index 0000000000..81768f7ed1 --- /dev/null +++ b/staticlibs/src_frameworkcommon/android/net/util/nsd/DnsSdTxtRecord.java @@ -0,0 +1,325 @@ +/* -*- Mode: Java; tab-width: 4 -*- + * + * Copyright (c) 2004 Apple Computer, Inc. All rights reserved. + * + * 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. + + To do: + - implement remove() + - fix set() to replace existing values + */ + +package android.net.util.nsd; + +import android.os.Parcelable; +import android.os.Parcel; + +import java.util.Arrays; + +/** + * This class handles TXT record data for DNS based service discovery as specified at + * http://tools.ietf.org/html/draft-cheshire-dnsext-dns-sd-11 + * + * DNS-SD specifies that a TXT record corresponding to an SRV record consist of + * a packed array of bytes, each preceded by a length byte. Each string + * is an attribute-value pair. + * + * The DnsSdTxtRecord object stores the entire TXT data as a single byte array, traversing it + * as need be to implement its various methods. + * @hide + * + */ +public class DnsSdTxtRecord implements Parcelable { + private static final byte mSeparator = '='; + + private byte[] mData; + + /** Constructs a new, empty TXT record. */ + public DnsSdTxtRecord() { + mData = new byte[0]; + } + + /** Constructs a new TXT record from a byte array in the standard format. */ + public DnsSdTxtRecord(byte[] data) { + mData = (byte[]) data.clone(); + } + + /** Copy constructor */ + public DnsSdTxtRecord(DnsSdTxtRecord src) { + if (src != null && src.mData != null) { + mData = (byte[]) src.mData.clone(); + } + } + + /** + * Set a key/value pair. Setting an existing key will replace its value. + * @param key Must be ascii with no '=' + * @param value matching value to key + */ + public void set(String key, String value) { + byte[] keyBytes; + byte[] valBytes; + int valLen; + + if (value != null) { + valBytes = value.getBytes(); + valLen = valBytes.length; + } else { + valBytes = null; + valLen = 0; + } + + try { + keyBytes = key.getBytes("US-ASCII"); + } + catch (java.io.UnsupportedEncodingException e) { + throw new IllegalArgumentException("key should be US-ASCII"); + } + + for (int i = 0; i < keyBytes.length; i++) { + if (keyBytes[i] == '=') { + throw new IllegalArgumentException("= is not a valid character in key"); + } + } + + if (keyBytes.length + valLen >= 255) { + throw new IllegalArgumentException("Key and Value length cannot exceed 255 bytes"); + } + + int currentLoc = remove(key); + if (currentLoc == -1) + currentLoc = keyCount(); + + insert(keyBytes, valBytes, currentLoc); + } + + /** + * Get a value for a key + * + * @param key + * @return The value associated with the key + */ + public String get(String key) { + byte[] val = this.getValue(key); + return val != null ? new String(val) : null; + } + + /** Remove a key/value pair. If found, returns the index or -1 if not found */ + public int remove(String key) { + int avStart = 0; + + for (int i=0; avStart < mData.length; i++) { + int avLen = mData[avStart]; + if (key.length() <= avLen && + (key.length() == avLen || mData[avStart + key.length() + 1] == mSeparator)) { + String s = new String(mData, avStart + 1, key.length()); + if (0 == key.compareToIgnoreCase(s)) { + byte[] oldBytes = mData; + mData = new byte[oldBytes.length - avLen - 1]; + System.arraycopy(oldBytes, 0, mData, 0, avStart); + System.arraycopy(oldBytes, avStart + avLen + 1, mData, avStart, + oldBytes.length - avStart - avLen - 1); + return i; + } + } + avStart += (0xFF & (avLen + 1)); + } + return -1; + } + + /** Return the count of keys */ + public int keyCount() { + int count = 0, nextKey; + for (nextKey = 0; nextKey < mData.length; count++) { + nextKey += (0xFF & (mData[nextKey] + 1)); + } + return count; + } + + /** Return true if key is present, false if not. */ + public boolean contains(String key) { + String s = null; + for (int i = 0; null != (s = this.getKey(i)); i++) { + if (0 == key.compareToIgnoreCase(s)) return true; + } + return false; + } + + /* Gets the size in bytes */ + public int size() { + return mData.length; + } + + /* Gets the raw data in bytes */ + public byte[] getRawData() { + return (byte[]) mData.clone(); + } + + private void insert(byte[] keyBytes, byte[] value, int index) { + byte[] oldBytes = mData; + int valLen = (value != null) ? value.length : 0; + int insertion = 0; + int newLen, avLen; + + for (int i = 0; i < index && insertion < mData.length; i++) { + insertion += (0xFF & (mData[insertion] + 1)); + } + + avLen = keyBytes.length + valLen + (value != null ? 1 : 0); + newLen = avLen + oldBytes.length + 1; + + mData = new byte[newLen]; + System.arraycopy(oldBytes, 0, mData, 0, insertion); + int secondHalfLen = oldBytes.length - insertion; + System.arraycopy(oldBytes, insertion, mData, newLen - secondHalfLen, secondHalfLen); + mData[insertion] = (byte) avLen; + System.arraycopy(keyBytes, 0, mData, insertion + 1, keyBytes.length); + if (value != null) { + mData[insertion + 1 + keyBytes.length] = mSeparator; + System.arraycopy(value, 0, mData, insertion + keyBytes.length + 2, valLen); + } + } + + /** Return a key in the TXT record by zero-based index. Returns null if index exceeds the total number of keys. */ + private String getKey(int index) { + int avStart = 0; + + for (int i=0; i < index && avStart < mData.length; i++) { + avStart += mData[avStart] + 1; + } + + if (avStart < mData.length) { + int avLen = mData[avStart]; + int aLen = 0; + + for (aLen=0; aLen < avLen; aLen++) { + if (mData[avStart + aLen + 1] == mSeparator) break; + } + return new String(mData, avStart + 1, aLen); + } + return null; + } + + /** + * Look up a key in the TXT record by zero-based index and return its value. + * Returns null if index exceeds the total number of keys. + * Returns null if the key is present with no value. + */ + private byte[] getValue(int index) { + int avStart = 0; + byte[] value = null; + + for (int i=0; i < index && avStart < mData.length; i++) { + avStart += mData[avStart] + 1; + } + + if (avStart < mData.length) { + int avLen = mData[avStart]; + int aLen = 0; + + for (aLen=0; aLen < avLen; aLen++) { + if (mData[avStart + aLen + 1] == mSeparator) { + value = new byte[avLen - aLen - 1]; + System.arraycopy(mData, avStart + aLen + 2, value, 0, avLen - aLen - 1); + break; + } + } + } + return value; + } + + private String getValueAsString(int index) { + byte[] value = this.getValue(index); + return value != null ? new String(value) : null; + } + + private byte[] getValue(String forKey) { + String s = null; + int i; + + for (i = 0; null != (s = this.getKey(i)); i++) { + if (0 == forKey.compareToIgnoreCase(s)) { + return this.getValue(i); + } + } + + return null; + } + + /** + * Return a string representation. + * Example : {key1=value1},{key2=value2}.. + * + * For a key say like "key3" with null value + * {key1=value1},{key2=value2}{key3} + */ + public String toString() { + String a, result = null; + + for (int i = 0; null != (a = this.getKey(i)); i++) { + String av = "{" + a; + String val = this.getValueAsString(i); + if (val != null) + av += "=" + val + "}"; + else + av += "}"; + if (result == null) + result = av; + else + result = result + ", " + av; + } + return result != null ? result : ""; + } + + @Override + public boolean equals(Object o) { + if (o == this) { + return true; + } + if (!(o instanceof DnsSdTxtRecord)) { + return false; + } + + DnsSdTxtRecord record = (DnsSdTxtRecord)o; + return Arrays.equals(record.mData, mData); + } + + @Override + public int hashCode() { + return Arrays.hashCode(mData); + } + + /** Implement the Parcelable interface */ + public int describeContents() { + return 0; + } + + /** Implement the Parcelable interface */ + public void writeToParcel(Parcel dest, int flags) { + dest.writeByteArray(mData); + } + + /** Implement the Parcelable interface */ + public static final @android.annotation.NonNull Creator CREATOR = + new Creator() { + public DnsSdTxtRecord createFromParcel(Parcel in) { + DnsSdTxtRecord info = new DnsSdTxtRecord(); + in.readByteArray(info.mData); + return info; + } + + public DnsSdTxtRecord[] newArray(int size) { + return new DnsSdTxtRecord[size]; + } + }; +}