Skip to content

GitLab

paul csharp 6.task · Changes

Page history
no message authored by paul's avatar paul
Hide whitespace changes
Inline Side-by-side
paul-csharp-6.task.md
View page @ ffb50ff5
......@@ -415,4 +415,177 @@ public async Task<int> SendRecvCommandAsync(TcpClient client, string ipAddr, str
// 생략
}
```
# 4. 예제 분석 2
EncClientManager는 UI프로그램과 장비간에 TCP 통신을 하는 모듈입니다.
UI와 장비간에는 통신 프로토콜이 정의되어 있구요, SendRecvCommandAsync() 메소드는 이를 구현한 메소드입니다.
시간되면 이 부분도 분석해 보면 좋겠습니다.
```csharp
// int를 반환하고 비동기로 수행될 메서드 선언
public async Task<int> SendRecvCommandAsync(TcpClient client, string ipAddr, string cmd, int ctag, int sessionID)
{
string myCmd = "%%" + cmd;
int calla_id = -1;
Trace.TraceInformation("[{4}] (THR:{5}) EncClientManager.SendRecvCommandAsync() begin : ipAddr={0}, ctag={1}, sess={2}, cmd={3}", ipAddr, ctag, sessionID, cmd, DateTime.Now, Thread.CurrentThread.ManagedThreadId);
try
{
// 비동기 호출로 해당 서버에 연결을 수행한다.
await client.ConnectAsync(ipAddr, EncClientManager.Port);
// 아래 코드는 비동기 호출이 완료되면 수행된다.
if (client.Connected)
{
using (var stream = client.GetStream())
{
///* 송신용 PDU 만들기 */
byte[] cmdBytes = Encoding.UTF8.GetBytes(myCmd);
int paddedCmdLen = cmdBytes.Length;
if ((paddedCmdLen % 2) == 1) /* 홀수 길이 */
paddedCmdLen++;
byte[] paddedCmdBytes = new byte[paddedCmdLen];
Array.Clear(paddedCmdBytes, 0, paddedCmdBytes.Length); /* == memset */
Array.Copy(cmdBytes, paddedCmdBytes, cmdBytes.Length);
byte[] sendBuffer = new byte[PDU_HDR_LEN + paddedCmdBytes.Length];
Array.Copy(PduSignature, sendBuffer, PduSignature.Length);
sendBuffer[(int)AppConst.PduHeader.version] = AppConst.PduDefaultVersion;
sendBuffer[(int)AppConst.PduHeader.type] = AppConst.PduRequestTL1;
ushort checksum = CRC.CheckSum16(paddedCmdBytes, paddedCmdBytes.Length);
byte[] checksumBytes = BitConverter.GetBytes(checksum);
Array.Reverse(checksumBytes);
Array.Copy(checksumBytes, 0, sendBuffer, (int)AppConst.PduHeader.checksun, checksumBytes.Length);
byte[] sessBytes = BitConverter.GetBytes(sessionID);
Array.Reverse(sessBytes);
Array.Copy(sessBytes, 0, sendBuffer, (int)AppConst.PduHeader.session, sessBytes.Length);
byte[] ctagBytes = BitConverter.GetBytes(ctag);
Array.Reverse(ctagBytes);
Array.Copy(ctagBytes, 0, sendBuffer, (int)AppConst.PduHeader.ctag, ctagBytes.Length);
byte[] lengthBytes = BitConverter.GetBytes(paddedCmdBytes.Length);
Array.Reverse(lengthBytes);
Array.Copy(lengthBytes, 0, sendBuffer, (int)AppConst.PduHeader.length, lengthBytes.Length);
Array.Copy(paddedCmdBytes, 0, sendBuffer, (int)AppConst.PduHeader.Size, paddedCmdBytes.Length);
// 연결된 TCP Client의 stream을 통해 명령어를 송신하고, 결과를 수신 받는다.
// WriteAsync, ReadAsyncs는 모두 비동기로 호출된다.
/* 명령어 송신 */
await stream.WriteAsync(sendBuffer, 0, sendBuffer.Length);
byte[] recvBuffer = new byte[AppConst.CallaBufferSize]; /* 수신 버퍼 */
int bytes; /* 수신 바이트수 */
/* 수신 PDU 까기 */
/* read HEADER */
bytes = await stream.ReadAsync(recvBuffer, 0, PDU_HDR_LEN);
if (bytes == 0)
{
Trace.TraceWarning("Command Execution FAIL. (HEADER Receive FAIL)");
return -1;
}
/* check signature */
bool isValidSignature = true;
for (int i = 0; i < PduSignature.Length; i++)
{
if (recvBuffer[i] != PduSignature[i])
{
isValidSignature = false;
break;
}
}
if (!isValidSignature)
{
Trace.TraceWarning("Command Execution FAIL. (SIGNATURE ERROR)");
return -1;
}
byte version;
byte type;
ushort recvChecksum;
int sessID;
int userTag;
int bodyLength;
version = recvBuffer[(int)AppConst.PduHeader.version];
type = recvBuffer[(int)AppConst.PduHeader.type];
if (type != AppConst.PduResponseCalla)
{
Trace.TraceWarning("**************************************");
Trace.TraceWarning("Command Execution FAIL. (TYPE MISMATCH : recv type = {0} != 1 (Calla Type))", type);
Trace.TraceWarning("**************************************");
return -1;
}
Array.Reverse(recvBuffer, (int)AppConst.PduHeader.checksun, 2);
recvChecksum = BitConverter.ToUInt16(recvBuffer, (int)AppConst.PduHeader.checksun);
Array.Reverse(recvBuffer, (int)AppConst.PduHeader.session, 4);
sessID = BitConverter.ToInt32(recvBuffer, (int)AppConst.PduHeader.session);
Array.Reverse(recvBuffer, (int)AppConst.PduHeader.ctag, 4);
userTag = BitConverter.ToInt32(recvBuffer, (int)AppConst.PduHeader.ctag);
if (userTag != ctag)
{
Trace.TraceWarning("**************************************");
Trace.TraceWarning("[{2}] (THR:{3}) Command Execution FAIL. (CTAG MISMATCH : sent ctag = {0}, recv ctag = {1})", ctag, userTag, DateTime.Now, Thread.CurrentThread.ManagedThreadId);
Trace.TraceWarning("**************************************");
return -1;
}
Array.Reverse(recvBuffer, (int)AppConst.PduHeader.length, 4);
bodyLength = BitConverter.ToInt32(recvBuffer, (int)AppConst.PduHeader.length);
/* read calla PDU */
int remainLength = bodyLength;
int destIndex = 0;
// PDU Header 정보를 이용해 calla 테이블 정보를 읽어들인다.
while (remainLength > 0)
{
int readAmount = await stream.ReadAsync(recvBuffer, destIndex, remainLength);
if (readAmount == 0)
{
Trace.TraceWarning("[{0}] (THR:{1}) Command Execution FAIL. (DATA RECEIVE FAIL)", DateTime.Now, Thread.CurrentThread.ManagedThreadId);
return -1;
}
remainLength -= readAmount;
destIndex += readAmount;
}
/* respons PDU --> calla PDU */
if (!Calla.SafeExtract(recvBuffer, bodyLength, out calla_id))
{
; // TODO.... PDU overflow or PDU crashed...
}
bool isValid = (Calla.valid(calla_id) == 1);
Trace.TraceInformation("[{5}] (THR:{6}) EncClientManager.SendRecvCommandAsync() complete : rsp calla({0}) isValid={1}, userTag={2}, seesID={3}, cmd={4}",
calla_id, isValid, userTag, sessID, cmd, DateTime.Now, Thread.CurrentThread.ManagedThreadId);
}
}
}
catch (Exception /*ex*/)
{
//Trace.TraceInformation("[{0}] Exception : {1}", DateTime.Now, ex.Message);
}
return calla_id;
}
```
\ No newline at end of file