com.smartdevicelink.transport.SdlPsm Maven / Gradle / Ivy
/*
* Copyright (c) 2019, Livio, Inc.
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package com.smartdevicelink.transport;
import com.smartdevicelink.protocol.SdlPacket;
import com.smartdevicelink.util.DebugTool;
import static com.smartdevicelink.protocol.SdlProtocol.V1_HEADER_SIZE;
import static com.smartdevicelink.protocol.SdlProtocol.V1_V2_MTU_SIZE;
import static com.smartdevicelink.protocol.SdlProtocol.V2_HEADER_SIZE;
import static com.smartdevicelink.protocol.SdlProtocol.V3_V4_MTU_SIZE;
public class SdlPsm {
private static final String TAG = "Sdl PSM";
//Each state represents the byte that should be incoming
public static final int START_STATE = 0x0;
public static final int SERVICE_TYPE_STATE = 0x02;
public static final int CONTROL_FRAME_INFO_STATE = 0x03;
public static final int SESSION_ID_STATE = 0x04;
public static final int DATA_SIZE_1_STATE = 0x05;
public static final int DATA_SIZE_2_STATE = 0x06;
public static final int DATA_SIZE_3_STATE = 0x07;
public static final int DATA_SIZE_4_STATE = 0x08;
public static final int MESSAGE_1_STATE = 0x09;
public static final int MESSAGE_2_STATE = 0x0A;
public static final int MESSAGE_3_STATE = 0x0B;
public static final int MESSAGE_4_STATE = 0x0C;
public static final int DATA_PUMP_STATE = 0x0D;
public static final int FINISHED_STATE = 0xFF;
public static final int ERROR_STATE = -1;
private static final byte FIRST_FRAME_DATA_SIZE = 0x08;
private static final int VERSION_MASK = 0xF0; //4 highest bits
private static final int ENCRYPTION_MASK = 0x08; //4th lowest bit
private static final int FRAME_TYPE_MASK = 0x07; //3 lowest bits
int state;
int version;
boolean encrypted;
int frameType;
int serviceType;
int controlFrameInfo;
int sessionId;
int dumpSize, dataLength;
int messageId = 0;
byte[] payload;
public SdlPsm() {
reset();
}
public boolean handleByte(byte data) {
try {
state = transitionOnInput(data, state);
} catch (Exception e) {
DebugTool.logError(TAG, "Exception thrown while parsing byte - " + data, e);
state = ERROR_STATE;
return false;
}
return state != ERROR_STATE;
}
private int transitionOnInput(byte rawByte, int state) {
switch (state) {
case START_STATE:
version = (rawByte & (byte) VERSION_MASK) >> 4;
encrypted = (1 == ((rawByte & (byte) ENCRYPTION_MASK) >> 3));
frameType = rawByte & (byte) FRAME_TYPE_MASK;
if ((version < 1 || version > 5)) {
//These are known versions supported by this library.
return ERROR_STATE;
}
if (frameType < SdlPacket.FRAME_TYPE_CONTROL || frameType > SdlPacket.FRAME_TYPE_CONSECUTIVE) {
return ERROR_STATE;
}
return SERVICE_TYPE_STATE;
case SERVICE_TYPE_STATE:
serviceType = (int) (rawByte & 0xFF);
switch (serviceType) {
case 0x00: //SessionType.CONTROL:
case 0x07: //SessionType.RPC:
case 0x0A: //SessionType.PCM (Audio):
case 0x0B: //SessionType.NAV (Video):
case 0x0F: //SessionType.BULK (Hybrid):
return CONTROL_FRAME_INFO_STATE;
default:
return ERROR_STATE;
}
case CONTROL_FRAME_INFO_STATE:
controlFrameInfo = (int) (rawByte & 0xFF);
//Log.trace(TAG,"Frame Info: " + controlFrameInfo);
switch (frameType) {
case SdlPacket.FRAME_TYPE_CONTROL:
/*if(frameInfoFRAME_INFO_END_SERVICE_ACK
&& (frameInfo!=FRAME_INFO_SERVICE_DATA_ACK || frameInfo!=FRAME_INFO_HEART_BEAT_ACK))){
return ERROR_STATE;
}*/ //Although some bits are reserved...whatever
break;
case SdlPacket.FRAME_TYPE_SINGLE: //Fall through since they are both the same
case SdlPacket.FRAME_TYPE_FIRST:
if (controlFrameInfo != 0x00) {
return ERROR_STATE;
}
break;
case SdlPacket.FRAME_TYPE_CONSECUTIVE:
//It might be a good idea to check packet sequence numbers here
break;
default:
return ERROR_STATE;
}
return SESSION_ID_STATE;
case SESSION_ID_STATE:
sessionId = (int) (rawByte & 0xFF);
return DATA_SIZE_1_STATE;
case DATA_SIZE_1_STATE:
//First data size byte
//Log.d(TAG, "Data byte 1: " + rawByte);
dataLength += ((int) (rawByte & 0xFF)) << 24; //3 bytes x 8 bits
//Log.d(TAG, "Data Size 1 : " + dataLength);
return DATA_SIZE_2_STATE;
case DATA_SIZE_2_STATE:
//Log.d(TAG, "Data byte 2: " + rawByte);
dataLength += ((int) (rawByte & 0xFF)) << 16; //2 bytes x 8 bits
//Log.d(TAG, "Data Size 2 : " + dataLength);
return DATA_SIZE_3_STATE;
case DATA_SIZE_3_STATE:
//Log.d(TAG, "Data byte 3: " + rawByte);
dataLength += ((int) (rawByte & 0xFF)) << 8; //1 byte x 8 bits
//Log.d(TAG, "Data Size 3 : " + dataLength);
return DATA_SIZE_4_STATE;
case DATA_SIZE_4_STATE:
//Log.d(TAG, "Data byte 4: " + rawByte);
dataLength += ((int) rawByte) & 0xFF;
//Log.trace(TAG, "Data Size: " + dataLength);
//We should have data length now for the pump state
switch (frameType) { //If all is correct we should break out of this switch statement
case SdlPacket.FRAME_TYPE_SINGLE:
case SdlPacket.FRAME_TYPE_CONSECUTIVE:
break;
case SdlPacket.FRAME_TYPE_CONTROL:
//Ok, well here's some interesting bit of knowledge. Because the start session request is from the phone with no knowledge of version it sends out
//a v1 packet. THEREFORE there is no message id field. **** Now you know and knowing is half the battle ****
if (version == 1 && controlFrameInfo == SdlPacket.FRAME_INFO_START_SERVICE) {
if (dataLength == 0) {
return FINISHED_STATE; //We are done if we don't have any payload
}
if (dataLength <= V1_V2_MTU_SIZE - V1_HEADER_SIZE) { // sizes from protocol/WiProProtocol.java
payload = new byte[dataLength];
} else {
return ERROR_STATE;
}
dumpSize = dataLength;
return DATA_PUMP_STATE;
}
break;
case SdlPacket.FRAME_TYPE_FIRST:
if (dataLength == FIRST_FRAME_DATA_SIZE || this.encrypted) {
//In a few production releases of core the first frame could be
//encrypted. Therefore it is not an error state if the first frame data
//length is greater than 8 in that case alone.
break;
}
default:
return ERROR_STATE;
}
switch (version) {
case 1:
//Version 1 packets will not have message id's
if (dataLength == 0) {
return FINISHED_STATE; //We are done if we don't have any payload
}
if (dataLength <= V1_V2_MTU_SIZE - V1_HEADER_SIZE) { // sizes from SDL protocol
payload = new byte[dataLength];
} else {
return ERROR_STATE;
}
dumpSize = dataLength;
return DATA_PUMP_STATE;
case 2:
if (dataLength <= V1_V2_MTU_SIZE - V2_HEADER_SIZE) {
return MESSAGE_1_STATE;
} else {
return ERROR_STATE;
}
case 3:
case 4:
if (dataLength <= V3_V4_MTU_SIZE - V2_HEADER_SIZE) {
return MESSAGE_1_STATE;
} else {
return ERROR_STATE;
}
default:
return MESSAGE_1_STATE;
}
case MESSAGE_1_STATE:
messageId += ((int) (rawByte & 0xFF)) << 24; //3 bytes x 8 bits
return MESSAGE_2_STATE;
case MESSAGE_2_STATE:
messageId += ((int) (rawByte & 0xFF)) << 16; //2 bytes x 8 bits
return MESSAGE_3_STATE;
case MESSAGE_3_STATE:
messageId += ((int) (rawByte & 0xFF)) << 8; //1 byte x 8 bits
return MESSAGE_4_STATE;
case MESSAGE_4_STATE:
messageId += ((int) rawByte) & 0xFF;
if (dataLength == 0) {
return FINISHED_STATE; //We are done if we don't have any payload
}
try {
payload = new byte[dataLength];
} catch (OutOfMemoryError oom) {
return ERROR_STATE;
}
dumpSize = dataLength;
return DATA_PUMP_STATE;
case DATA_PUMP_STATE:
payload[dataLength - dumpSize] = rawByte;
dumpSize--;
//Do we have any more bytes to read in?
if (dumpSize > 0) {
return DATA_PUMP_STATE;
} else if (dumpSize == 0) {
return FINISHED_STATE;
} else {
return ERROR_STATE;
}
case FINISHED_STATE: //We shouldn't be here...Should have been reset
default:
return ERROR_STATE;
}
}
public SdlPacket getFormedPacket() {
if (state == FINISHED_STATE) {
//Log.trace(TAG, "Finished packet.");
return new SdlPacket(version, encrypted, frameType,
serviceType, controlFrameInfo, sessionId,
dataLength, messageId, payload);
} else {
return null;
}
}
public int getState() {
return state;
}
public void reset() {
version = 0;
state = START_STATE;
messageId = 0;
dataLength = 0;
frameType = 0x00; //Set it to null
payload = null;
}
}
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