/*
* Copyright (C) 2010 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.gsm;
import android.telephony.SmsCbConstants;
public class SmsCbHeader implements SmsCbConstants {
/**
* Length of SMS-CB header
*/
public static final int PDU_HEADER_LENGTH = 6;
/**
* GSM pdu format, as defined in 3gpp TS 23.041, section 9.4.1
*/
public static final int FORMAT_GSM = 1;
/**
* UMTS pdu format, as defined in 3gpp TS 23.041, section 9.4.2
*/
public static final int FORMAT_UMTS = 2;
/**
* GSM pdu format, as defined in 3gpp TS 23.041, section 9.4.1.3
*/
public static final int FORMAT_ETWS_PRIMARY = 3;
/**
* Message type value as defined in 3gpp TS 25.324, section 11.1.
*/
private static final int MESSAGE_TYPE_CBS_MESSAGE = 1;
/**
* Length of GSM pdus
*/
public static final int PDU_LENGTH_GSM = 88;
/**
* Maximum length of ETWS primary message GSM pdus
*/
public static final int PDU_LENGTH_ETWS = 56;
public final int geographicalScope;
public final int messageCode;
public final int updateNumber;
public final int messageIdentifier;
public final int dataCodingScheme;
public final int pageIndex;
public final int nrOfPages;
public final int format;
public final boolean etwsEmergencyUserAlert;
public final boolean etwsPopup;
public final int etwsWarningType;
public SmsCbHeader(byte[] pdu) throws IllegalArgumentException {
if (pdu == null || pdu.length < PDU_HEADER_LENGTH) {
throw new IllegalArgumentException("Illegal PDU");
}
if (pdu.length <= PDU_LENGTH_ETWS) {
format = FORMAT_ETWS_PRIMARY;
geographicalScope = -1; //not applicable
messageCode = -1;
updateNumber = -1;
messageIdentifier = ((pdu[2] & 0xff) << 8) | (pdu[3] & 0xff);
dataCodingScheme = -1;
pageIndex = -1;
nrOfPages = -1;
etwsEmergencyUserAlert = (pdu[4] & 0x1) != 0;
etwsPopup = (pdu[5] & 0x80) != 0;
etwsWarningType = (pdu[4] & 0xfe) >> 1;
} else if (pdu.length <= PDU_LENGTH_GSM) {
// GSM pdus are no more than 88 bytes
format = FORMAT_GSM;
geographicalScope = (pdu[0] & 0xc0) >> 6;
messageCode = ((pdu[0] & 0x3f) << 4) | ((pdu[1] & 0xf0) >> 4);
updateNumber = pdu[1] & 0x0f;
messageIdentifier = ((pdu[2] & 0xff) << 8) | (pdu[3] & 0xff);
dataCodingScheme = pdu[4] & 0xff;
// Check for invalid page parameter
int pageIndex = (pdu[5] & 0xf0) >> 4;
int nrOfPages = pdu[5] & 0x0f;
if (pageIndex == 0 || nrOfPages == 0 || pageIndex > nrOfPages) {
pageIndex = 1;
nrOfPages = 1;
}
this.pageIndex = pageIndex;
this.nrOfPages = nrOfPages;
etwsEmergencyUserAlert = false;
etwsPopup = false;
etwsWarningType = -1;
} else {
// UMTS pdus are always at least 90 bytes since the payload includes
// a number-of-pages octet and also one length octet per page
format = FORMAT_UMTS;
int messageType = pdu[0];
if (messageType != MESSAGE_TYPE_CBS_MESSAGE) {
throw new IllegalArgumentException("Unsupported message type " + messageType);
}
messageIdentifier = ((pdu[1] & 0xff) << 8) | pdu[2] & 0xff;
geographicalScope = (pdu[3] & 0xc0) >> 6;
messageCode = ((pdu[3] & 0x3f) << 4) | ((pdu[4] & 0xf0) >> 4);
updateNumber = pdu[4] & 0x0f;
dataCodingScheme = pdu[5] & 0xff;
// We will always consider a UMTS message as having one single page
// since there's only one instance of the header, even though the
// actual payload may contain several pages.
pageIndex = 1;
nrOfPages = 1;
etwsEmergencyUserAlert = false;
etwsPopup = false;
etwsWarningType = -1;
}
}
/**
* Return whether the specified message ID is an emergency (PWS) message type.
* This method is static and takes an argument so that it can be used by
* CellBroadcastReceiver, which stores message ID's in SQLite rather than PDU.
* @param id the message identifier to check
* @return true if the message is emergency type; false otherwise
*/
public static boolean isEmergencyMessage(int id) {
return id >= MESSAGE_ID_PWS_FIRST_IDENTIFIER && id <= MESSAGE_ID_PWS_LAST_IDENTIFIER;
}
/**
* Return whether the specified message ID is an ETWS emergency message type.
* This method is static and takes an argument so that it can be used by
* CellBroadcastReceiver, which stores message ID's in SQLite rather than PDU.
* @param id the message identifier to check
* @return true if the message is ETWS emergency type; false otherwise
*/
public static boolean isEtwsMessage(int id) {
return (id & MESSAGE_ID_ETWS_TYPE_MASK) == MESSAGE_ID_ETWS_TYPE;
}
/**
* Return whether the specified message ID is a CMAS emergency message type.
* This method is static and takes an argument so that it can be used by
* CellBroadcastReceiver, which stores message ID's in SQLite rather than PDU.
* @param id the message identifier to check
* @return true if the message is CMAS emergency type; false otherwise
*/
public static boolean isCmasMessage(int id) {
return id >= MESSAGE_ID_CMAS_FIRST_IDENTIFIER && id <= MESSAGE_ID_CMAS_LAST_IDENTIFIER;
}
/**
* Return whether the specified message code indicates an ETWS popup alert.
* This method is static and takes an argument so that it can be used by
* CellBroadcastReceiver, which stores message codes in SQLite rather than PDU.
* This method assumes that the message ID has already been checked for ETWS type.
*
* @param messageCode the message code to check
* @return true if the message code indicates a popup alert should be displayed
*/
public static boolean isEtwsPopupAlert(int messageCode) {
return (messageCode & MESSAGE_CODE_ETWS_ACTIVATE_POPUP) != 0;
}
/**
* Return whether the specified message code indicates an ETWS emergency user alert.
* This method is static and takes an argument so that it can be used by
* CellBroadcastReceiver, which stores message codes in SQLite rather than PDU.
* This method assumes that the message ID has already been checked for ETWS type.
*
* @param messageCode the message code to check
* @return true if the message code indicates an emergency user alert
*/
public static boolean isEtwsEmergencyUserAlert(int messageCode) {
return (messageCode & MESSAGE_CODE_ETWS_EMERGENCY_USER_ALERT) != 0;
}
@Override
public String toString() {
return "SmsCbHeader{GS=" + geographicalScope + ", messageCode=0x" +
Integer.toHexString(messageCode) + ", updateNumber=" + updateNumber +
", messageIdentifier=0x" + Integer.toHexString(messageIdentifier) +
", DCS=0x" + Integer.toHexString(dataCodingScheme) +
", page " + pageIndex + " of " + nrOfPages + '}';
}
}