Merge "Add new class AnswerToReset for ATR parsing" (b4a9738e) · Commits · e / os / android_frameworks_opt_telephony

src/java/com/android/internal/telephony/AnswerToReset.java

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		/*
		* Copyright 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.internal.telephony;

		import android.annotation.Nullable;
		import android.telephony.Rlog;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.internal.telephony.uicc.IccUtils;

		import java.io.FileDescriptor;
		import java.io.PrintWriter;
		import java.util.ArrayList;
		import java.util.List;
		import java.util.Objects;

		/**
		* This class parses an Answer To Reset (ATR) message.
		* The ATR message structure is defined in standard ISO/IEC 7816-3. The eUICC related ATR message
		* is defined in standard ETSI TS 102 221 V14.0.0.
		*/
		public class AnswerToReset {
		private static final String TAG = "AnswerToReset";
		private static final boolean VDBG = false; // STOPSHIP if true

		public static final byte EUICC_SUPPORTED = (byte) 0x82;
		public static final byte DIRECT_CONVENTION = (byte) 0x3B;
		public static final byte INVERSE_CONVENTION = (byte) 0x3F;
		public static final int INTERFACE_BYTES_MASK = 0xF0;
		public static final int T_MASK = 0x0F;
		public static final int T_VALUE_FOR_GLOBAL_INTERFACE = 15;
		public static final int TA_MASK = 0x10;
		public static final int TB_MASK = 0x20;
		public static final int TC_MASK = 0x40;
		public static final int TD_MASK = 0x80;

		private boolean mIsDirectConvention;
		private boolean mOnlyTEqualsZero = true;
		private boolean mIsEuiccSupported;
		private byte mFormatByte;
		private ArrayList<InterfaceByte> mInterfaceBytes = new ArrayList<>();
		private byte[] mHistoricalBytes;
		private Byte mCheckByte;

		/**
		* Returns an AnswerToReset by parsing the input atr string, return null if the parsing fails.
		*/
		public static AnswerToReset parseAtr(String atr) {
		AnswerToReset answerToReset = new AnswerToReset();
		if (answerToReset.parseAtrString(atr)) {
		return answerToReset;
		}
		return null;
		}

		private AnswerToReset() {}

		private static String byteToStringHex(Byte b) {
		return b == null ? null : IccUtils.byteToHex(b);
		}

		private void checkIsEuiccSupported() {
		// eUICC is supported only if the value of the first tB after T=15 is 82.
		for (int i = 0; i < mInterfaceBytes.size() - 1; i++) {
		if (mInterfaceBytes.get(i).getTD() != null
		&& (mInterfaceBytes.get(i).getTD() & T_MASK) == T_VALUE_FOR_GLOBAL_INTERFACE
		&& mInterfaceBytes.get(i + 1).getTB() != null
		&& mInterfaceBytes.get(i + 1).getTB() == EUICC_SUPPORTED) {
		mIsEuiccSupported = true;
		return;
		}
		}
		}

		private int parseConventionByte(byte[] atrBytes, int index) {
		if (index >= atrBytes.length) {
		loge("Failed to read the convention byte.");
		return -1;
		}
		byte value = atrBytes[index];
		if (value == DIRECT_CONVENTION) {
		mIsDirectConvention = true;
		} else if (value == INVERSE_CONVENTION) {
		mIsDirectConvention = false;
		} else {
		loge("Unrecognized convention byte " + IccUtils.byteToHex(value));
		return -1;
		}
		return index + 1;
		}

		private int parseFormatByte(byte[] atrBytes, int index) {
		if (index >= atrBytes.length) {
		loge("Failed to read the format byte.");
		return -1;
		}
		mFormatByte = atrBytes[index];
		mHistoricalBytes = new byte[mFormatByte & T_MASK];
		if (VDBG) log("mHistoricalBytesLength: " + mHistoricalBytes.length);
		return index + 1;
		}

		private int parseInterfaceBytes(byte[] atrBytes, int index) {
		// The first lastTD is actually not any TD but instead the format byte.
		byte lastTD = mFormatByte;
		while (true) {
		if (VDBG) log("lastTD: " + IccUtils.byteToHex(lastTD));
		// Parse the interface bytes.
		if ((lastTD & INTERFACE_BYTES_MASK) == 0) {
		break;
		}

		InterfaceByte interfaceByte = new InterfaceByte();
		if (VDBG) log("lastTD & TA_MASK: " + IccUtils.byteToHex((byte) (lastTD & TA_MASK)));
		if ((lastTD & TA_MASK) != 0) {
		if (index >= atrBytes.length) {
		loge("Failed to read the byte for TA.");
		return -1;
		}
		interfaceByte.setTA(atrBytes[index]);
		index++;
		}
		if (VDBG) log("lastTD & TB_MASK: " + IccUtils.byteToHex((byte) (lastTD & TB_MASK)));
		if ((lastTD & TB_MASK) != 0) {
		if (index >= atrBytes.length) {
		loge("Failed to read the byte for TB.");
		return -1;
		}
		interfaceByte.setTB(atrBytes[index]);
		index++;
		}
		if (VDBG) log("lastTD & TC_MASK: " + IccUtils.byteToHex((byte) (lastTD & TC_MASK)));
		if ((lastTD & TC_MASK) != 0) {
		if (index >= atrBytes.length) {
		loge("Failed to read the byte for TC.");
		return -1;
		}
		interfaceByte.setTC(atrBytes[index]);
		index++;
		}
		if (VDBG) log("lastTD & TD_MASK: " + IccUtils.byteToHex((byte) (lastTD & TD_MASK)));
		if ((lastTD & TD_MASK) != 0) {
		if (index >= atrBytes.length) {
		loge("Failed to read the byte for TD.");
		return -1;
		}
		interfaceByte.setTD(atrBytes[index]);
		index++;
		}
		mInterfaceBytes.add(interfaceByte);
		Byte newTD = interfaceByte.getTD();
		if (VDBG) log("index=" + index + ", " + toString());
		if (newTD == null) {
		break;
		}
		lastTD = newTD;
		// Parse the T values from all the TD, here we only check whether T is equal to any
		// other values other than 0, since the check byte can be absent only when T is
		// equal to 0.
		if ((lastTD & T_MASK) != 0) {
		mOnlyTEqualsZero = false;
		}
		}
		return index;
		}

		private int parseHistoricalBytes(byte[] atrBytes, int index) {
		if (mHistoricalBytes.length + index > atrBytes.length) {
		loge("Failed to read the historical bytes.");
		return -1;
		}
		if (mHistoricalBytes.length > 0) {
		System.arraycopy(atrBytes, index, mHistoricalBytes, 0, mHistoricalBytes.length);
		}
		return index + mHistoricalBytes.length;
		}

		private int parseCheckBytes(byte[] atrBytes, int index) {
		if (index < atrBytes.length) {
		mCheckByte = atrBytes[index];
		index++;
		} else {
		if (!mOnlyTEqualsZero) {
		loge("Check byte must be present because T equals to values other than 0.");
		return -1;
		} else {
		log("Check byte can be absent because T=0.");
		}
		}
		return index;
		}

		private boolean parseAtrString(String atr) {
		if (atr.length() % 2 != 0) {
		loge("The length of input ATR string " + atr.length() + " is not even.");
		return false;
		}

		if (atr.length() < 4) {
		loge("Valid ATR string must at least contains TS and T0.");
		return false;
		}

		byte[] atrBytes = IccUtils.hexStringToBytes(atr);
		if (atrBytes == null) {
		return false;
		}

		int index = parseConventionByte(atrBytes, 0);
		if (index == -1) {
		return false;
		}

		index = parseFormatByte(atrBytes, index);
		if (index == -1) {
		return false;
		}

		index = parseInterfaceBytes(atrBytes, index);
		if (index == -1) {
		return false;
		}

		index = parseHistoricalBytes(atrBytes, index);
		if (index == -1) {
		return false;
		}

		index = parseCheckBytes(atrBytes, index);
		if (index == -1) {
		return false;
		}

		if (index != atrBytes.length) {
		loge("Unexpected bytes after the check byte.");
		return false;
		}
		log("Successfully parsed the ATR string " + atr + " into " + toString());
		checkIsEuiccSupported();
		return true;
		}

		/**
		* This class holds the interface bytes.
		*/
		public static class InterfaceByte {
		private Byte mTA;
		private Byte mTB;
		private Byte mTC;
		private Byte mTD;

		@Nullable
		public Byte getTA() {
		return mTA;
		}

		@Nullable
		public Byte getTB() {
		return mTB;
		}

		@Nullable
		public Byte getTC() {
		return mTC;
		}

		@Nullable
		public Byte getTD() {
		return mTD;
		}

		public void setTA(Byte tA) {
		mTA = tA;
		}

		public void setTB(Byte tB) {
		mTB = tB;
		}

		public void setTC(Byte tC) {
		mTC = tC;
		}

		public void setTD(Byte tD) {
		mTD = tD;
		}

		private InterfaceByte() {
		mTA = null;
		mTB = null;
		mTC = null;
		mTD = null;
		}

		@VisibleForTesting
		public InterfaceByte(Byte tA, Byte tB, Byte tC, Byte tD) {
		this.mTA = tA;
		this.mTB = tB;
		this.mTC = tC;
		this.mTD = tD;
		}

		@Override
		public boolean equals(Object o) {
		if (this == o) {
		return true;
		}
		if (o == null \|\| getClass() != o.getClass()) {
		return false;
		}
		InterfaceByte ib = (InterfaceByte) o;
		return (Objects.equals(mTA, ib.getTA())
		&& Objects.equals(mTB, ib.getTB())
		&& Objects.equals(mTC, ib.getTC())
		&& Objects.equals(mTD, ib.getTD()));
		}

		@Override
		public int hashCode() {
		return Objects.hash(mTA, mTB, mTC, mTD);
		}

		@Override
		public String toString() {
		StringBuffer sb = new StringBuffer();
		sb.append("{");
		sb.append("TA=").append(byteToStringHex(mTA)).append(",");
		sb.append("TB=").append(byteToStringHex(mTB)).append(",");
		sb.append("TC=").append(byteToStringHex(mTC)).append(",");
		sb.append("TD=").append(byteToStringHex(mTD));
		sb.append("}");
		return sb.toString();
		}
		};

		private static void log(String msg) {
		Rlog.d(TAG, msg);
		}

		private static void loge(String msg) {
		Rlog.e(TAG, msg);
		}

		public byte getConventionByte() {
		return mIsDirectConvention ? DIRECT_CONVENTION : INVERSE_CONVENTION;
		}

		public byte getFormatByte() {
		return mFormatByte;
		}

		public List<InterfaceByte> getInterfaceBytes() {
		return mInterfaceBytes;
		}

		@Nullable
		public byte[] getHistoricalBytes() {
		return mHistoricalBytes;
		}

		@Nullable
		public Byte getCheckByte() {
		return mCheckByte;
		}

		public boolean isEuiccSupported() {
		return mIsEuiccSupported;
		}

		@Override
		public String toString() {
		StringBuffer sb = new StringBuffer();

		sb.append("AnswerToReset:{");
		sb.append("mConventionByte=")
		.append(IccUtils.byteToHex(getConventionByte())).append(",");
		sb.append("mFormatByte=").append(byteToStringHex(mFormatByte)).append(",");
		sb.append("mInterfaceBytes={");
		for (InterfaceByte ib : mInterfaceBytes) {
		sb.append(ib.toString());
		}
		sb.append("},");
		sb.append("mHistoricalBytes={");
		for (byte b : mHistoricalBytes) {
		sb.append(IccUtils.byteToHex(b)).append(",");
		}
		sb.append("},");
		sb.append("mCheckByte=").append(byteToStringHex(mCheckByte));
		sb.append("}");
		return sb.toString();
		}

		/**
		* Dump
		*/
		public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
		pw.println("AnswerToReset:");
		pw.println(toString());
		pw.flush();
		}
		}

tests/telephonytests/src/com/android/internal/telephony/AnswerToResetTest.java

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