Develop Reference

Problem implementing C# listener for Concox GPS tracker HVT001

I am trying to implement a C# listener for a Concox GPS tracker (model HVT001) using the code examples that are available online but for some reason I am not able to get the Terminal ID (IMEI) correctly and I can't get any location messages after the login
Below is a screen capture of the input from my console window:
As you can see the Terminal ID appears as gibberish and no location messages appear (I'm also getting protocol numbers that I don't recognize)
Any help would be appreciated.
The full code is available here: https://docs.google.com/document/d/1UsF7ocb5CsCI1rxTcJHLP2eejR6vvboD_M8UeadkVmI/edit?usp=sharing
And here is a snippet of the code:
public void ProcessMessages()
{
UInt16 sendCRC = 0;
DateTime date;
int year = 0;
int month = 0;
int day = 0;
int hour = 0;
int minute = 0;
int second = 0;
KeyValuePair<List<byte>, StateObject> byteState;
KeyValuePair<UNPACK_STATUS, byte[]> status;
byte[] receiveMessage = null;
StateObject state = null;
byte[] serialNumber = null;
byte[] serverFlagBit = null;
byte[] stringArray = null;
string stringMessage = "";
byte lengthOfCommand = 0;
PROTOCOL_NUMBER protocolNumber = PROTOCOL_NUMBER.NONE;
try
{
Boolean firstMessage = true;
acceptDone.Set();
//loop forever
while (true)
{
allDone.WaitOne();
//read fifo until empty
while (true)
{
//read one connection until buffer doesn't contain any more packets
byteState = ReadWrite(PROCESS_STATE.PROCESS, null, null, -1);
if (byteState.Value.fifoCount == -1) break;
state = byteState.Value;
while (true)
{
status = Unpack(byteState);
if (status.Key == UNPACK_STATUS.NOT_ENOUGH_BYTES)
break;
if (status.Key == UNPACK_STATUS.ERROR)
{
Console.WriteLine("Error : Bad Receive Message, Data");
break;
}
//message is 2 start bytes + 1 byte (message length) + 1 byte message length + 2 end bytes
receiveMessage = status.Value;
int messageLength = receiveMessage[2];
Console.WriteLine("Status : '{0}', Receive Message : '{1}'", status.Key == UNPACK_STATUS.GOOD_MESSAGE ? "Good" : "Bad", BytesToString(receiveMessage.Take(messageLength + 5).ToArray()));
if (status.Key != UNPACK_STATUS.GOOD_MESSAGE)
{
break;
}
else
{
if (firstMessage)
{
if (receiveMessage[3] != 0x01)
{
Console.WriteLine("Error : Expected Login Message : '{0}'", BytesToString(receiveMessage));
break;
}
firstMessage = false;
}
//skip start bytes, message length. then go back 4 bytes (CRC and serial number)
serialNumber = receiveMessage.Skip(2 + 1 + messageLength - 4).Take(2).ToArray();
protocolNumber = (PROTOCOL_NUMBER)receiveMessage[3];
Console.WriteLine("Protocol Number : '{0}'", protocolNumber.ToString());
switch (protocolNumber)
{
case PROTOCOL_NUMBER.LOGIN_MESSAGE:
serialNumber.CopyTo(loginResponse, 4);
sendCRC = crc_bytes(loginResponse.Skip(2).Take(loginResponse.Length - 6).ToArray());
loginResponse[loginResponse.Length - 4] = (byte)((sendCRC >> 8) & 0xFF);
loginResponse[loginResponse.Length - 3] = (byte)((sendCRC) & 0xFF);
string IMEI = Encoding.ASCII.GetString(receiveMessage.Skip(4).Take(messageLength - 5).ToArray());
Console.WriteLine("Received good login message from Serial Number : '{0}', Terminal ID = '{1}'", "0x" + serialNumber[0].ToString("X2") + serialNumber[1].ToString("X2"), IMEI);
//byteState.Value.IMEI = IMEI;
Console.WriteLine("Send Message : '{0}'", BytesToString(loginResponse));
Send(state.workSocket, loginResponse);
WriteDBMessageLogin loginMessage = new WriteDBMessageLogin() { message = DATABASE_MESSAGE_TYPE.LOGIN, IMEI = IMEI, date = DateTime.Now };
WriteDBAsync.ReadWriteFifo(WriteDBAsync.Mode.WRITE, loginMessage);
Console.WriteLine("Wrote to database");
break;
case PROTOCOL_NUMBER.LOCATION_DATA:
year = receiveMessage[4];
month = receiveMessage[5];
day = receiveMessage[6];
hour = receiveMessage[7];
minute = receiveMessage[8];
second = receiveMessage[9];
date = new DateTime(2000 + year, month, day, hour, minute, second);
WriteDBMessageLocation locationMessage = new WriteDBMessageLocation();
locationMessage.message = DATABASE_MESSAGE_TYPE.LOCATION;
locationMessage.trackTime = date;
locationMessage.currTime = DateTime.Now;
locationMessage.lattitude = new byte[4];
Array.Copy(receiveMessage, 11, locationMessage.lattitude, 0, 4);
locationMessage.longitude = new byte[4];
Array.Copy(receiveMessage, 15, locationMessage.longitude, 0, 4);
locationMessage.speed = receiveMessage[19];
locationMessage.courseStatus = new byte[2];
Array.Copy(receiveMessage, 20, locationMessage.courseStatus, 0, 2);
locationMessage.IMEI = byteState.Value.IMEI;
WriteDBAsync.ReadWriteFifo(WriteDBAsync.Mode.WRITE, locationMessage);
Console.WriteLine("Received good location message from Serial Number '{0}', Time = '{1}'", "0x" + serialNumber[0].ToString("X2") + serialNumber[1].ToString("X2"), date.ToLongDateString());
break;
case PROTOCOL_NUMBER.ALARM_DATA:
//first response
int alarmPacketLen = alarmResponse.Length - 5;
alarmResponse[2] = (byte)(alarmPacketLen & 0xFF);
serialNumber.CopyTo(alarmResponse, alarmPacketLen - 1);
sendCRC = crc_bytes(alarmResponse.Skip(2).Take(alarmPacketLen - 1).ToArray());
alarmResponse[alarmPacketLen + 1] = (byte)((sendCRC >> 8) & 0xFF);
alarmResponse[alarmPacketLen + 2] = (byte)((sendCRC) & 0xFF);
Console.WriteLine("Send Alarm Response Message : '{0}'", BytesToString(alarmResponse));
Send(state.workSocket, alarmResponse);
//second response
year = receiveMessage[4];
month = receiveMessage[5];
day = receiveMessage[6];
hour = receiveMessage[7];
minute = receiveMessage[8];
second = receiveMessage[9];
date = new DateTime(2000 + year, month, day, hour, minute, second);
Console.WriteLine("Received good alarm message from Serial Number '{0}', Time = '{1}'", "0x" + serialNumber[0].ToString("X2") + serialNumber[1].ToString("X2"), date.ToLongDateString());
int alarmDataAddressPacketLen = alarmDataAddressResponse.Length - 5;
alarmDataAddressResponse[2] = (byte)(alarmDataAddressPacketLen & 0xFF);
serialNumber.CopyTo(alarmDataAddressResponse, alarmDataAddressPacketLen - 1);
sendCRC = crc_bytes(alarmDataAddressResponse.Skip(2).Take(alarmDataAddressPacketLen - 1).ToArray());
alarmDataAddressResponse[alarmDataAddressPacketLen + 1] = (byte)((sendCRC >> 8) & 0xFF);
alarmDataAddressResponse[alarmDataAddressPacketLen + 2] = (byte)((sendCRC) & 0xFF);
Console.WriteLine("Send Alarm Data Address Message : '{0}'", BytesToString(alarmDataAddressResponse));
Send(state.workSocket, alarmDataAddressResponse);
break;
case PROTOCOL_NUMBER.STATUS_INFO:
serialNumber.CopyTo(heartbeatResponse, 4);
byte info = receiveMessage[4];
byte voltage = receiveMessage[5];
byte GSMsignalStrength = receiveMessage[6];
UInt16 alarmLanguage = (UInt16)((receiveMessage[7] << 8) | receiveMessage[8]);
ALARM alarm = (ALARM)((info >> 3) & 0x07);
sendCRC = crc_bytes(heartbeatResponse.Skip(2).Take(heartbeatResponse.Length - 6).ToArray());
heartbeatResponse[heartbeatResponse.Length - 4] = (byte)((sendCRC >> 8) & 0xFF);
heartbeatResponse[heartbeatResponse.Length - 3] = (byte)((sendCRC) & 0xFF);
Console.WriteLine("Received good status message from Serial Number : '{0}', INFO : '0x{1}{2}{3}{4}'",
"0x" + serialNumber[0].ToString("X2") + serialNumber[1].ToString("X2"),
info.ToString("X2"), voltage.ToString("X2"), GSMsignalStrength.ToString("X2"),
alarmLanguage.ToString("X4"));
Console.WriteLine("Send Message : '{0}'", BytesToString(heartbeatResponse));
Send(state.workSocket, heartbeatResponse);
switch (alarm)
{
//reset cut off alarm
case ALARM.POWER_CUT_ALARM:
int connectOilAndElectricityPacketLen = connectOilAndEletricity.Length - 5;
serialNumber.CopyTo(connectOilAndEletricity, connectOilAndElectricityPacketLen - 1);
sendCRC = crc_bytes(connectOilAndEletricity.Skip(2).Take(connectOilAndEletricity.Length - 6).ToArray());
connectOilAndEletricity[connectOilAndEletricity.Length - 4] = (byte)((sendCRC >> 8) & 0xFF);
connectOilAndEletricity[connectOilAndEletricity.Length - 3] = (byte)((sendCRC) & 0xFF);
serverFlagBit = new byte[4];
Array.Copy(connectOilAndEletricity, 5, serverFlagBit, 0, 4);
lengthOfCommand = connectOilAndEletricity[4];
stringArray = new byte[lengthOfCommand - 4]; //do not include server flag bit
Array.Copy(connectOilAndEletricity, 9, stringArray, 0, lengthOfCommand - 4);
stringMessage = Encoding.ASCII.GetString(stringArray);
Console.WriteLine("Reset Oil and Electricity, Server Flag Bit : '{0}{1}{2}{3}', Message : '{4}'",
serverFlagBit[0].ToString("X2"),
serverFlagBit[1].ToString("X2"),
serverFlagBit[2].ToString("X2"),
serverFlagBit[3].ToString("X2"),
stringMessage);
Send(state.workSocket, connectOilAndEletricity);
break;
}
break;
case PROTOCOL_NUMBER.STRING_INFO:
lengthOfCommand = receiveMessage[4];
serverFlagBit = new byte[4];
Array.Copy(receiveMessage, 5, serverFlagBit, 0, 4);
stringArray = new byte[lengthOfCommand - 4]; //do not include server flag bit
Array.Copy(receiveMessage, 9, stringArray, 0, lengthOfCommand - 4);
stringMessage = Encoding.ASCII.GetString(stringArray);
Console.WriteLine("String Message, Server Flag Bit : '{0}{1}{2}{3}', Message : '{4}'",
serverFlagBit[0].ToString("X2"),
serverFlagBit[1].ToString("X2"),
serverFlagBit[2].ToString("X2"),
serverFlagBit[3].ToString("X2"),
stringMessage);
break;
} //end switch
}// End if
} //end while
}//end while fifo > 0
allDone.Reset();
}//end while true
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}

First of all, a google docs is no way to share code bear that in mind for next questions. I cant really test your code, but from what i read in the documentacion of this GPS. I can tell you that your IMEI problem is that you are not desearializing it well.
According to the documentacion the Login Message Packet has 18 bytes, and its divided this way in order
2 as start bit
1 for the length of the package
1 for the protocol number (in this case protocol 1 or 0x01)
8 for the IMEI as a example this IMEI 123456789123456 gets sent like this: 0x01
0x23 0x45 0x67 0x89 0x120x34 0x56
2 for serial information on the number
2 for error check
and 2 more for stop
Here is your line where you deserialize it:
string IMEI = Encoding.ASCII.GetString(receiveMessage.Skip(4).Take(messageLength - 5).ToArray());
To begin with there is no need to make a calculation on how many you should take, they will always be 8 so receiveMessage.Skip(4).Take(8).ToArray()
Then there is the problem with the encoding, you dont want to convert those numbers into their ascii char, you want only to take the numbers being writen as a hex string, removing the dashes that generates the method, and removing the leading zero if any exists
BitConverter.ToString(ByteArr).Replace("-","").TrimStart('0')
This is how your IMEI variable should look like:
string IMEI = BitConverter.ToString(receiveMessage.Skip(4).Take(8).ToArray()).Replace("-","").TrimStart('0');

Read mobile phone book using obex in c#

i have a OBEXConnect and OBEXRequest custom functions, i am not using library for it
OBEXConnect function is as following
private bool OBEXConnect()
{
//send client request
byte[] ConnectPacket = new byte[7];
ConnectPacket[0] = 0x80; // Connect
ConnectPacket[1] = 0x00; // Packetlength Hi Byte
ConnectPacket[2] = 0x07; // Packetlength Lo Byte
ConnectPacket[3] = 0x10; // Obex v1
ConnectPacket[4] = 0x00; // no flags
ConnectPacket[5] = 0x20; // 8k max packet size Hi Byte
ConnectPacket[6] = 0x00; // 8k max packet size Lo Byte
stream.Write(ConnectPacket,0,ConnectPacket.Length);
//listen for server response
byte[] ReceiveBufferA = new byte[3];
stream.Read(ReceiveBufferA,0,3);
if (ReceiveBufferA[0] == 160) // 0xa0
{
//success, decode rest of packet
int plength = (0xff * ReceiveBufferA[1]) + ReceiveBufferA[2]; //length of packet is...
//listen for rest of packet
byte[] ReceiveBufferB = new byte[plength-3];
stream.Read(ReceiveBufferB,0,plength-3);
int obver = ReceiveBufferB[0]; //server obex version (16 = v1.0)
int cflags = ReceiveBufferB[1]; //connect flags
int maxpack = (0xff * ReceiveBufferB[2]) + ReceiveBufferB[3]; //max packet size
return true;
}
else
{
return false;
}
}
and here is OBEXRequest function
private int OBEXRequest(string tReqType, string tName, string tType, string tFileContent)
{
//send client request
int i;
int offset;
int packetsize;
byte reqtype = 0x82;
int tTypeLen = 0x03;
int typeheadsize;
int typesizeHi = 0x00;
int typesizeLo = 0x03;
//tName = "contact.vcf";
//tType = "text/x-vCard";
//tFileContent = "BEGIN:VCARD\r\nVERSION:2.1\r\nN:;aardvark\r\nFN:aardvark\r\nEND:VCARD\r\n";
if (tReqType == "GET")
{
reqtype = 0x83; // 131 GET-Final
}
if (tReqType == "PUT")
{
reqtype = 0x82; // 130 PUT-Final
}
packetsize = 3;
//Name Header
int tNameLength = tName.Length;
int nameheadsize = (3 + (tNameLength*2) + 2);
int namesizeHi = (nameheadsize & 0xff00)/0xff;
int namesizeLo = nameheadsize & 0x00ff;
packetsize = packetsize + nameheadsize;
if (tType != "")
{
//Type Header
tTypeLen = tType.Length;
typeheadsize = 3 + tTypeLen + 1;
typesizeHi = (typeheadsize & 0xff00)/0xff;
typesizeLo = typeheadsize & 0x00ff;
packetsize = packetsize + typeheadsize;
}
//Body
int fileLen = tFileContent.Length;
int fileheadsize = 3 + fileLen ;
int filesizeHi = (fileheadsize & 0xff00)/0xff;;
int filesizeLo = fileheadsize & 0x00ff;;
packetsize = packetsize + fileheadsize;
int packetsizeHi = (packetsize & 0xff00)/0xff;
int packetsizeLo = packetsize & 0x00ff;
byte[] tSendByte = new byte[packetsize];
//PUT-final Header
tSendByte[0] = reqtype; // Request type e.g. PUT-final 130
tSendByte[1] = Convert.ToByte(packetsizeHi); // Packetlength Hi
tSendByte[2] = Convert.ToByte(packetsizeLo); // Packetlength Lo
offset = 2;
//Name Header
tSendByte[offset+1] = 0x01; // HI for Name header
tSendByte[offset+2] = Convert.ToByte(namesizeHi); // Length of Name header (2 bytes per char)
tSendByte[offset+3] = Convert.ToByte(namesizeLo); // Length of Name header (2 bytes per char)
// Name+\n\n in unicode
byte[] tNameU = System.Text.Encoding.BigEndianUnicode.GetBytes(tName);
tNameU.CopyTo(tSendByte,offset+4);
offset = offset + 3 + (tNameLength*2);
tSendByte[offset+1] = 0x00; // null term
tSendByte[offset+2] = 0x00; // null term
offset = offset + 2;
if (tType != "")
{
//Type Header
tSendByte[offset+1] = 0x42; // HI for Type Header 66
tSendByte[offset+2] = Convert.ToByte(typesizeHi); // Length of Type Header
tSendByte[offset+3] = Convert.ToByte(typesizeLo); // Length of Type Header
for (i=0;i<=(tTypeLen-1);i++)
{
tSendByte[offset+4+i] = Convert.ToByte(Convert.ToChar(tType.Substring(i,1)));
}
tSendByte[offset+3+tTypeLen+1] = 0x00; // null terminator
offset = offset+3+tTypeLen+1;
}
//Body
tSendByte[offset+1] = 0x49; //HI End of Body 73
tSendByte[offset+2] = Convert.ToByte(filesizeHi); //
tSendByte[offset+3] = Convert.ToByte(filesizeLo); //1k payload + 3 for HI header
for (i=0;i<=(fileLen-1);i++)
{
tSendByte[offset+4+i] = Convert.ToByte(Convert.ToChar(tFileContent.Substring(i,1)));
}
//tSendByte[offset+4+fileLen] = 0x00; // null terminator
offset = offset+3+fileLen;
stream.Write(tSendByte,0,tSendByte.Length );
//listen for server response
//TODO: can hang here forever waiting response...
bool x = stream.DataAvailable; // changed bluetoothclient - public NetworkStream GetStream()
byte[] tArray4 = new byte[3];
stream.Read(tArray4,0,3);
x = stream.DataAvailable;
if (tArray4[0] == 160) // 0xa0
{
int plength = (tArray4[1] * 256) + tArray4[2] - 3;
byte[] tArray5 = new byte[plength];
if (plength >0)
{
stream.Read(tArray5,0,plength);
//TODO: data in returned packet to deal with
}
return 160;
}
if (tArray4[0] == 197) // 0xc5 Method not allowed
{
return 197;
}
if (tArray4[0] == 192) // 0xc0 Bad Request
{
return 192;
}
return 0;
}
i want to read the phone book of mobile but i not succeeded yet
i try on one samsung mobile it gives error bad request i follow the solutions above mentioned but when name = null then obexrequest function gives error
when i try it on huawei mobile it gives unknown error
i try this code as well it throw error that this method is not implemented
Read contacts using obex in c#
i call these functions like this
string tName = "";
string tType = "text/x-vCard";
string tFileContent = "";
int result = OBEXRequest("GET",tName,tType,tFileContent);
switch (result)
{
case 160: // 0xa0
addtolog("OK");
break;
case 197: // 0xc5
addtolog("Method not allowed");
break;
case 192: // 0xc0
addtolog("Bad Request");
break;
default:
addtolog("Other Error");
break;
}
can any body point out my mistake

Strange packets arrive on C# websocket server from Chrome websocket client

I have a C# server side websocket code, and I am sending test data from Chrome (javascript websocket client).
Following this: https://stackoverflow.com/a/8125509/2508439, and some other link, I created my C# webserver (server side) decode function as following:
public String DecodeMessage(Byte[] bytes)
{
Console.WriteLine("+DecodeMessage+");
String incomingData = String.Empty;
Byte secondByte = bytes[1];
bool masked = (bytes[1] & 128) != 0;
//long dataLength = secondByte & 127;
dataLength = secondByte & 127;
//Int32 indexFirstMask = 2;
indexFirstMask = 2;
if (masked)
{
Console.WriteLine("Masked bit SET");
}
if (dataLength == 126)
{
indexFirstMask = 4;
dataLength = bytes[3] | bytes[2] << 8;
}
else if (dataLength == 127)
{
indexFirstMask = 10;
dataLength = bytes[9] | bytes[8] << 8 | bytes[7] << 16 | bytes[6] << 24 | bytes[5] << 32 |
bytes[4] << 40 | bytes[3] << 48 | bytes[2] << 56;
}
//IEnumerable<Byte> keys = bytes.Skip(indexFirstMask).Take(4);
keys = bytes.Skip(indexFirstMask).Take(4);
Int32 indexFirstDataByte = indexFirstMask + 4;
Byte[] decoded = new Byte[bytes.Length - indexFirstDataByte];
Console.WriteLine("dataLength : " + dataLength + " ; bytes.Length : " + bytes.Length);
Int32 j = 0;
for (Int32 i = indexFirstDataByte; i < bytes.Length; i++)
{
decoded[j] = (Byte)(bytes[i] ^ keys.ElementAt(j % 4));
j++;
}
Console.WriteLine("-DecodeMessage-");
return incomingData = Encoding.UTF8.GetString(decoded, 0, decoded.Length);
}
public String DecodeRemainingMessage(Byte[] bytes, long bytesAlreadyRead)
{
Console.WriteLine("+DecodeRemainingMessage+");
String incomingData = String.Empty;
Int32 indexFirstDataByte = 0;
if ( indexFirstMask == 10 )//special case, what to do here?
{
indexFirstDataByte = 10;
}
Byte[] decoded = new Byte[bytes.Length - indexFirstDataByte];
//Byte[] decoded = new Byte[bytes.Length];
Int32 j = 0;
for (Int32 i = indexFirstDataByte; i < bytes.Length; i++)
{
decoded[j] = (Byte)(bytes[i] ^ keys.ElementAt(j % 4));
j++;
}
Console.WriteLine("-DecodeRemainingMessage-");
return incomingData = Encoding.UTF8.GetString(decoded, 0, decoded.Length);
}
Simple packets (125 size or less arrive just fine).
In case of size about 125 and less than 65535, also arrive fine (kind of: there is some detail but I'm not going in that right now [*]).
Packets above 65535: the whole decode function goes crazy:
Only the first time packet is decoded properly, and after that, what ever data I receive is totally binary (unreadable), and after the first packet arrives, in consecutive packets:
if (dataLength == 126)
{
...
}
else if (dataLength == 127) ...
both conditions are never fulfilled, and dataLength is always less than 126, which is then decoded as (small) packet, and hence never reconstructed properly.
Can anyone highlight what I may be doing wrong?
Thanks
[*]=> data below 65535 length sometimes comes in more than two packets, which then behaves the same way as the larger packets, and packets after the first time this function is hit never gets reconstructed again properly.
edit 1:
#Marc
Based on your comment, I have put the 'masked bit check' in above function, and I can see it is always set to '1' (as expected since this is only server side code for now).
I am also parsing the control frame in a different function, and in this function, provided my code is correct, I may be getting lots of junk data.
To elaborate, please see these functions below:
whole logical code:
The enum:
public enum ControlFrame { NA=0, CloseConnection=1, Ping=2, Pong=4, Text=8, Binary=16, ContinueFrame =32, FinalFrame=64 };
The parse control frame function:
private int ParseControlFrame(byte controlFrame)
{
int rv = (int)ControlFrame.NA;
bool isFinalFrame = (controlFrame & 0x80) == 0x80 ;
byte opCode = (byte)((controlFrame & 0x0F));
if ( opCode >= 0x3 && opCode <= 0x7 ||
opCode >= 0xB && opCode <= 0xF )//special frame, ignore it
{
Console.WriteLine("Reserved Frame received");
return rv;
}
if (opCode == 0x8 || opCode == 0x0 || opCode == 0x1 || opCode == 0x2 || opCode == 0x9 || opCode == 0xA) //proceed furter
{
if (opCode == 0x0) //continue frame
{
rv |= (int)ControlFrame.ContinueFrame;
Console.WriteLine("Continue Frame received");
}
if (opCode == 0x1) //text frame
{
rv |= (int)ControlFrame.Text;
Console.WriteLine("Text Frame received");
}
if (opCode == 0x2) //binary frame
{
rv |= (int)ControlFrame.Binary;
Console.WriteLine("Binary frame received");
}
if (opCode == 0x8) //connection closed
{
rv |= (int)ControlFrame.CloseConnection;
Console.WriteLine("CloseConnection Frame received");
}
if (opCode == 0x9) //ping
{
rv |= (int)ControlFrame.Ping;
Console.WriteLine("PING received");
}
if (opCode == 0xA) //pong
{
rv |= (int)ControlFrame.Pong;
Console.WriteLine("PONG received");
}
}
else // invalid control bit, must close the connection
{
Console.WriteLine("invalid control frame received, must close connection");
rv = (int)ControlFrame.CloseConnection;
}
if (isFinalFrame) //Final frame ...
{
rv |= (int)ControlFrame.FinalFrame;
Console.WriteLine("Final frame received");
}
//else
//{
// rv |= (int)ControlFrame.ContinueFrame;
// Console.WriteLine("Continue frame received");
//}
return rv;
}
Logical flow (code snippet from actual):
if (stream.DataAvailable)
{
long bytesAlreadyRead = 0;
bool breakMain = false;
while (client.Available > 0 )
{
byte[] bytes = new byte[client.Available];
stream.Read(bytes, 0, bytes.Length);
Console.WriteLine("if (stream.DataAvailable):\nclient.Available : " + client.Available +
" ; bytes.Length : " + bytes.Length);
//translate bytes of request to string
String data = Encoding.UTF8.GetString(bytes);
Console.WriteLine("Message received on: " + DateTime.Now);
if (bytesAlreadyRead == 0)
{
int controlFrame = ParseControlFrame(bytes[0]);
if (controlFrame == (int)ControlFrame.NA ||
(int)(controlFrame & (int)ControlFrame.Ping) > 0 ||
(int)(controlFrame & (int)ControlFrame.Pong) > 0) //ignore it
{
}
else
{
if ((int)(controlFrame & (int)ControlFrame.CloseConnection) > 0)
{
Console.WriteLine("Connection #" + c.Key + " Closed on: " + DateTime.Now);
tcpClients.Remove(c.Key);
breakMain = true;
break;
}
else
{
string result = c.Value.DecodeMessage(bytes);
File.WriteAllText("recvfile.txt", result);
}
}
}
else
{
string result = c.Value.DecodeRemainingMessage(bytes, bytesAlreadyRead);
File.AppendAllText("recvfile.txt", "\n");
File.AppendAllText("recvfile.txt", result);
}
bytesAlreadyRead += bytes.Length;
}
if ( breakMain == true )
{
break;
}
}
I don't get garbage but data is missed.
If I don't put this check, then, I start receiving garbage.
Based on Console.WriteLine output, I see something similar for data less than 65535:
Message received on: 12/29/2017 12:59:00 PM
Text Frame received
Final frame received
Masked bit SET
Message received on: 12/29/2017 12:59:12 PM
Text Frame received
Final frame received
Masked bit SET
For data above 65535:
Message received on: 12/29/2017 1:02:51 PM
Text Frame received
Final frame received
Masked bit SET
Message received on: 12/29/2017 1:02:51 PM
Reserved Frame received
i.e. Less than 65535, I am ok (most of the time).
With above 65535, things get strange.
When you mentioned:
I wonder if what is happening is that you're getting multiple messages in a single Read call (perfectly normal in TCP), consuming the first message, and incorrectly treating the entire bytes as consumed.
I never thought of this before, maybe I need to handle this somehow as well?
edit 2:
Based on your comment, i have modified the 'if (stream.DataAvailable)' logic, so it keeps on reading data in while loop until all data stored locally is actually flushed out.
So i may be close to solving it (thanks for your feedback), but the 2nd time DecodeMessage() function is called, it still decrypts in garbage (binary) data.
I am working on figuring it out!
Thanks
edit 3:
Ok, based on your suggestion, I have sorted out most of the logic. However, special case in 'DecodeRemainingMessage' function is what still remains a mystery. [I shifted some variables from local to class scope, hence they are commented out in functions]...
If I got it correct, I should not need to place any special condition here, but in that case, I still receive garbage.
Any pointers?
[sorry for the messy code, will update it once I get the right picture!]
Thanks
edit 4:
Following all your advises in comments/chat helped me get to the point where I updated decode logic greatly, and was still unable to get right data in case of above 65535 bytes. But when I tried final logic with Firefox, I got all the data properly! So many thanks to you, and, I still need to figure out how to handle buggy Chrome client! Thanks!!

Edit: your code assumes that the incoming frames are always masked. This is probably OK if your code is only ever a server, but you might want to check whether bytes[1] & 128 is set (masked) or clear (not masked). If it isn't masked: the header is 4 bytes shorter. You should be OK if this is only ever a server, as (from 5.2 in RFC6455):
All frames sent from client to server have this bit set to 1.
but: it would be good to double-check. You'd be amazed how many buggy clients there are in the wild that violate the specification.
--
The overall code looks fine, and is broadly comparable to what I have here. I can't see anything immediately wrong. This makes me suspect that the issue here is TCP streaming; it isn't obvious that you method is doing anything to report back what quantity of bytes should be logically consumed by this frame - i.e. the total header length plus the payload length. For comparison to my code, this would be out int headerLength and frame.PayloadLength combined.
I wonder if what is happening is that you're getting multiple messages in a single Read call (perfectly normal in TCP), consuming the first message, and incorrectly treating the entire bytes as consumed. This would mean that you start reading in the wrong place for the next frame header. A single Read invoke can return a fragment of one frame, exactly one frame, or more than one frame - the only thing it can't return is 0 bytes, unless the socket has closed.

Android base64 hash mismatch with server side hash using C# script

I am creating base64 hash using HMAC SHA256 in my Android application. and send it on server for match with server side hash.
Following this tutorial.
Working Android code:
public String getHash(String data,String key)
{
try
{
String secret = key;
String message = data;
Mac sha256_HMAC = Mac.getInstance("HmacMD5");
SecretKeySpec secret_key = new SecretKeySpec(secret.getBytes(), "HmacMD5");
sha256_HMAC.init(secret_key);
String hash = Base64.encodeBase64String(sha256_HMAC.doFinal(message.getBytes()));
System.out.println(hash);
return hash;
}
catch (Exception e){
System.out.println("Error");
}
}
server code is in C# script and its as per below
using System.Security.Cryptography;
namespace Test
{
public class MyHmac
{
private string CreateToken(string message, string secret)
{
secret = secret ?? "";
var encoding = new System.Text.ASCIIEncoding();
byte[] keyByte = encoding.GetBytes(secret);
byte[] messageBytes = encoding.GetBytes(message);
using (var hmacsha256 = new HMACSHA256(keyByte))
{
byte[] hashmessage = hmacsha256.ComputeHash(messageBytes);
return Convert.ToBase64String(hashmessage);
}
}
}
}
but hash key generated at android side is not match with server side and below is objective c code which generate same as C# code
objective c code:
#import "AppDelegate.h"
#import <CommonCrypto/CommonHMAC.h>
#implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSString* key = #"secret";
NSString* data = #"Message";
const char *cKey = [key cStringUsingEncoding:NSASCIIStringEncoding];
const char *cData = [data cStringUsingEncoding:NSASCIIStringEncoding];
unsigned char cHMAC[CC_SHA256_DIGEST_LENGTH];
CCHmac(kCCHmacAlgSHA256, cKey, strlen(cKey), cData, strlen(cData), cHMAC);
NSData *hash = [[NSData alloc] initWithBytes:cHMAC length:sizeof(cHMAC)];
NSLog(#"%#", hash);
NSString* s = [AppDelegate base64forData:hash];
NSLog(s);
}
+ (NSString*)base64forData:(NSData*)theData
{
const uint8_t* input = (const uint8_t*)[theData bytes];
NSInteger length = [theData length];
static char table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
NSMutableData* data = [NSMutableData dataWithLength:((length + 2) / 3) * 4];
uint8_t* output = (uint8_t*)data.mutableBytes;
NSInteger i;
for (i=0; i < length; i += 3) {
NSInteger value = 0;
NSInteger j;
for (j = i; j < (i + 3); j++) {
value <<= 8;
if (j < length) { value |= (0xFF & input[j]);
}
}
NSInteger theIndex = (i / 3) * 4; output[theIndex + 0] = table[(value >> 18) & 0x3F];
output[theIndex + 1] = table[(value >> 12) & 0x3F];
output[theIndex + 2] = (i + 1) < length ? table[(value >> 6) & 0x3F] : '=';
output[theIndex + 3] = (i + 2) < length ? table[(value >> 0) & 0x3F] : '=';
}
return [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
}
#end
please help me to sove out this issue,
Thanks in advance.
I have solved this issue by changing HmacSHA256 to HmacMD5 and its give same hash value as given by C# code.
I have updated my question with working code. check it

I suspect this is an encoding issue.
In one sample you specify the string should be encoded using ASCII when converting the string to a byte array. In the other sample you do not specify an encoding.
If the default encoding is anything other than ASCII that means the byte arrays will be different, leading to different hash results.

In android secret.getBytes may get UTF-16 bytes, check the length of the result. In general separate such functions out into separate statements for easier debugging.
Not the answer, rather a demonstration of a simpler Obj-C implementation and provides the hash and Base64 vaules:
NSString* key = #"secret";
NSString* data = #"Message";
NSData *keyData = [key dataUsingEncoding:NSASCIIStringEncoding];
NSData *dataData = [data dataUsingEncoding:NSASCIIStringEncoding];
NSMutableData *hash = [NSMutableData dataWithLength:CC_SHA256_DIGEST_LENGTH];
CCHmac(kCCHmacAlgSHA256, keyData.bytes, keyData.length , dataData.bytes, dataData.length, hash.mutableBytes);
NSLog(#"hash: %#", hash);
NSString* s = [hash base64EncodedStringWithOptions:0];
NSLog(#"s: %#", s);
Output:
hash: <aa747c50 2a898200 f9e4fa21 bac68136 f886a0e2 7aec70ba 06daf2e2 a5cb5597>
s: qnR8UCqJggD55PohusaBNviGoOJ67HC6Btry4qXLVZc=

Calculate an Internet (aka IP, aka RFC791) checksum in C#

Interestingly, I can find implementations for the Internet Checksum in almost every language except C#. Does anyone have an implementation to share?
Remember, the internet protocol specifies that:
"The checksum field is the 16 bit one's complement of the one's
complement sum of all 16 bit words in the header. For purposes of
computing the checksum, the value of the checksum field is zero."
More explanation can be found from Dr. Math.
There are some efficiency pointers available, but that's not really a large concern for me at this point.
Please include your tests! (Edit: Valid comment regarding testing someone else's code - but I am going off of the protocol and don't have test vectors of my own and would rather unit test it than put into production to see if it matches what is currently being used! ;-)
Edit: Here are some unit tests that I came up with. They test an extension method which iterates through the entire byte collection. Please comment if you find fault in the tests.
[TestMethod()]
public void InternetChecksum_SimplestValidValue_ShouldMatch()
{
IEnumerable<byte> value = new byte[1]; // should work for any-length array of zeros
ushort expected = 0xFFFF;
ushort actual = value.InternetChecksum();
Assert.AreEqual(expected, actual);
}
[TestMethod()]
public void InternetChecksum_ValidSingleByteExtreme_ShouldMatch()
{
IEnumerable<byte> value = new byte[]{0xFF};
ushort expected = 0xFF;
ushort actual = value.InternetChecksum();
Assert.AreEqual(expected, actual);
}
[TestMethod()]
public void InternetChecksum_ValidMultiByteExtrema_ShouldMatch()
{
IEnumerable<byte> value = new byte[] { 0x00, 0xFF };
ushort expected = 0xFF00;
ushort actual = value.InternetChecksum();
Assert.AreEqual(expected, actual);
}

I knew I had this one stored away somewhere...
http://cyb3rspy.wordpress.com/2008/03/27/ip-header-checksum-function-in-c/

Well, I dug up an implementation from an old code base and it passes the tests I specified in the question, so here it is (as an extension method):
public static ushort InternetChecksum(this IEnumerable<byte> value)
{
byte[] buffer = value.ToArray();
int length = buffer.Length;
int i = 0;
UInt32 sum = 0;
UInt32 data = 0;
while (length > 1)
{
data = 0;
data = (UInt32)(
((UInt32)(buffer[i]) << 8)
|
((UInt32)(buffer[i + 1]) & 0xFF)
);
sum += data;
if ((sum & 0xFFFF0000) > 0)
{
sum = sum & 0xFFFF;
sum += 1;
}
i += 2;
length -= 2;
}
if (length > 0)
{
sum += (UInt32)(buffer[i] << 8);
//sum += (UInt32)(buffer[i]);
if ((sum & 0xFFFF0000) > 0)
{
sum = sum & 0xFFFF;
sum += 1;
}
}
sum = ~sum;
sum = sum & 0xFFFF;
return (UInt16)sum;
}

I have made an implementation of the IPv4 header checksum calculation, as defined in RFC 791.
Extension Methods
public static ushort GetInternetChecksum(this ReadOnlySpan<byte> bytes)
=> CalculateChecksum(bytes, ignoreHeaderChecksum: true);
public static bool IsValidChecksum(this ReadOnlySpan<byte> bytes)
// Should equal zero (valid)
=> CalculateChecksum(bytes, ignoreHeaderChecksum: false) == 0;
The Checksum Calculation
using System.Buffers.Binary;
private static ushort CalculateChecksum(ReadOnlySpan<byte> bytes, bool ignoreHeaderChecksum)
{
ushort checksum = 0;
for (int i = 0; i <= 18; i += 2)
{
// i = 0 e.g. [0..2] Version and Internal Header Length
// i = 2 e.g. [2..4] Total Length
// i = 4 e.g. [4..6] Identification
// i = 6 e.g. [6..8] Flags and Fragmentation Offset
// i = 8 e.g. [8..10] TTL and Protocol
// i = 10 e.g. [10..12] Header Checksum
// i = 12 e.g. [12..14] Source Address #1
// i = 14 e.g. [14..16] Source Address #2
// i = 16 e.g. [16..18] Destination Address #1
// i = 18 e.g. [18..20] Destination Address #2
if (ignoreHeaderChecksum && i == 10) continue;
ushort value = BinaryPrimitives.ReadUInt16BigEndian(bytes[i..(i + 2)]);
// Each time a carry occurs, we must add a 1 to the sum
if (checksum + value > ushort.MaxValue)
{
checksum++;
}
checksum += value;
}
// One’s complement
return (ushort)~checksum;
}