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🍻 Add TLS concept #1

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1 change: 1 addition & 0 deletions OMJSON.fun
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ FUNCTION_BLOCK jsonWebSocketServer (*Serve variables via JSON and WebSockets*) (
BufferSize : UDINT; (*Size of buffers. N buffers will be allocated, so the total memory requirement is N*BufferSize.*)
MaxIterations : UDINT; (*Maximum number of iterations for looping through variables.*)
AcknowledgeError : BOOL; (*Acknowledge errors. Automatically reset by FUB.*)
CertID : UDINT;
END_VAR
VAR_OUTPUT
ClientInfo : ARRAY[0..JSON_MAI_CLIENTS] OF jsonWSS_client_info_typ;
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3 changes: 3 additions & 0 deletions OMJSON.typ
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Expand Up @@ -47,6 +47,7 @@ TYPE
END_STRUCT;
jsonWSS_client_debug_typ : STRUCT
socketConnectCount : DINT;
connectSplit : DINT;
websocketConnectCount : DINT;
socketDisconnectCountError : DINT;
socketDisconnectCountRecvLength0 : DINT;
Expand All @@ -63,6 +64,8 @@ TYPE
tcpStream : TCPStream_typ;
pReceiveData : UDINT;
pSendData : UDINT;
pRecieveDataBuffer : UDINT;
recieveDataBufferLen : UDINT;
messageBuffer : datbufBuffer_typ;
wsConnect : jsonWSConnect;
wsConnected : BOOL;
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172 changes: 123 additions & 49 deletions jsonWebSocketServer.c
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Expand Up @@ -79,6 +79,7 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)
// Allocate send and receive memory and initialize message buffer
if ( (TMP_alloc( t->BufferSize, (void**)&(t->internal.client[index].pReceiveData) ) != 0)
|| (TMP_alloc( t->BufferSize, (void**)&(t->internal.client[index].pSendData) ) != 0)
|| (TMP_alloc( t->BufferSize, (void**)&(t->internal.client[index].pRecieveDataBuffer) ) != 0)
|| (datbufInitBuffer( (UDINT)&(t->internal.client[index].messageBuffer), t->BufferSize ) != 0)
) {
jsonInternalSetWSServerError( JSON_ERR_MEMALLOC, t );
Expand All @@ -90,6 +91,8 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)

// Set up tcpServer
t->internal.tcpServer.IN.CFG.Mode = TCPCOMM_MODE_SERVER;
t->internal.tcpServer.IN.CFG.UseSSL = 1; // Lets try it �\_(?)_/�
t->internal.tcpServer.IN.CFG.SSLCertificate = t->CertID;
Comment on lines +94 to +95
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@sclaiborne sclaiborne Apr 8, 2021

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This should be configurable

strcpy(t->internal.tcpServer.IN.CFG.LocalIPAddress, t->ServerIP);
t->internal.tcpServer.IN.CFG.LocalPort = t->ServerPort;
t->internal.tcpServer.IN.CFG.SendBufferSize = t->BufferSize;
Expand Down Expand Up @@ -157,6 +160,9 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)

t->internal.client[t->internal.iClient].wsConnected = 0;

t->internal.client[index].recieveDataBufferLen = 0;
((char*)t->internal.client[index].pRecieveDataBuffer)[0] = '\0';

// Clear cache
t->internal.client[t->internal.iClient].pCache = &(((jsonCache_typ*)t->pCacheArray)[t->internal.iClient]);
t->internal.client[t->internal.iClient].pCache->iItem = 0; // Lazy clear cache
Expand Down Expand Up @@ -245,51 +251,77 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)

t->internal.client[index].wsConnected = 0;
t->internal.client[index].debug.socketDisconnectCountRecvLength0++;

//t->internal.client[index].tcpStream.IN.PAR.pReceiveData = t->internal.client[index].pReceiveData;

continue;

}

t->internal.client[index].tcpStream.IN.CMD.AcknowledgeData = 1;

// Check for connection attempt
BOOL shouldConnect = 0;

// Option 1: Check entire receive data with a strstr() for "Sec-WebSocket-Key:"
// This could be slow for very large receive data lengths
// Receive length for HTTP request to open websocket from Chrome is 486 bytes
// Small websocket request receive length is < 100 bytes
//shouldConnect = (strstr((char*)t->internal.client[index].tcpStream.IN.PAR.pReceiveData, "Sec-WebSocket-Key:") != 0);

// Option 2: Copy first 500 bytes and check with a strstr() for "Sec-WebSocket-Key:"
// This could be faster for very large receive data lengths
//STRING messageBeginning[500+1];
//memset(&messageBeginning, 0, sizeof(messageBeginning));
//memcpy(&messageBeginning, (char*)t->internal.client[index].tcpStream.IN.PAR.pReceiveData, sizeof(messageBeginning)-1);
//shouldConnect = (strstr(messageBeginning, "Sec-WebSocket-Key:") != 0);

// Option 3: Check first 3 bytes for GET
// This should be the fastest for small and large receive lengths
// Could break down with weirdly formatted request (shouldn't happen)
shouldConnect = (memcmp((char*)t->internal.client[index].pReceiveData, "GET", 3) == 0);

if (shouldConnect) {

// Establish WebSocket connection
t->internal.client[index].wsConnect.pInputMessage = t->internal.client[index].pReceiveData;
t->internal.client[index].wsConnect.pOutputMessage = t->internal.client[index].pSendData;
t->internal.client[index].wsConnect.MaxOutputMessageLength = t->BufferSize;
jsonWSConnect(&t->internal.client[index].wsConnect);

if (t->internal.client[index].wsConnect.Status == 0) {
t->internal.client[index].tcpStream.IN.PAR.SendLength = t->internal.client[index].wsConnect.OutputMessageLength;
t->internal.client[index].tcpStream.IN.CMD.Send = 1;
t->internal.client[index].wsConnected = 1;
t->internal.client[index].debug.websocketConnectCount++;
} else {
jsonInternalSetWSServerError(t->internal.client[index].wsConnect.Status, t);

if (!t->internal.client[index].wsConnected) {

// If partial packet
// TODO: We need to do something here to handle recieving the HTTP frame in multiple packets
// TODO: This is a hacky solution and probably doesnt work in all cases but it does for fire fox in my test case
if (t->internal.client[index].tcpStream.OUT.ReceivedDataLength < 10) {
t->internal.client[index].tcpStream.IN.PAR.pReceiveData = t->internal.client[index].pReceiveData + t->internal.client[index].tcpStream.OUT.ReceivedDataLength;
t->internal.client[index].tcpStream.IN.PAR.MaxReceiveLength = t->BufferSize - (t->internal.client[index].tcpStream.IN.PAR.pReceiveData - t->internal.client[index].pReceiveData);
t->internal.client[index].debug.connectSplit++;
continue;
}



// Check for connection attempt
BOOL shouldConnect = 0;

// Option 1: Check entire receive data with a strstr() for "Sec-WebSocket-Key:"
// This could be slow for very large receive data lengths
// Receive length for HTTP request to open websocket from Chrome is 486 bytes
// Small websocket request receive length is < 100 bytes
//shouldConnect = (strstr((char*)t->internal.client[index].tcpStream.IN.PAR.pReceiveData, "Sec-WebSocket-Key:") != 0);

// Option 2: Copy first 500 bytes and check with a strstr() for "Sec-WebSocket-Key:"
// This could be faster for very large receive data lengths
//STRING messageBeginning[500+1];
//memset(&messageBeginning, 0, sizeof(messageBeginning));
//memcpy(&messageBeginning, (char*)t->internal.client[index].tcpStream.IN.PAR.pReceiveData, sizeof(messageBeginning)-1);
//shouldConnect = (strstr(messageBeginning, "Sec-WebSocket-Key:") != 0);

// Option 3: Check first 3 bytes for GET
// This should be the fastest for small and large receive lengths
// Could break down with weirdly formatted request (shouldn't happen)
shouldConnect = (memcmp((char*)t->internal.client[index].pReceiveData, "GET", 3) == 0);




if (shouldConnect) {

// Reset partial packet
t->internal.client[index].tcpStream.IN.PAR.pReceiveData = t->internal.client[index].pReceiveData;
t->internal.client[index].tcpStream.IN.PAR.MaxReceiveLength = t->BufferSize;

// Establish WebSocket connection
t->internal.client[index].wsConnect.pInputMessage = t->internal.client[index].pReceiveData;
t->internal.client[index].wsConnect.pOutputMessage = t->internal.client[index].pSendData;
t->internal.client[index].wsConnect.MaxOutputMessageLength = t->BufferSize;
jsonWSConnect(&t->internal.client[index].wsConnect);

if (t->internal.client[index].wsConnect.Status == 0) {
t->internal.client[index].tcpStream.IN.PAR.SendLength = t->internal.client[index].wsConnect.OutputMessageLength;
t->internal.client[index].tcpStream.IN.CMD.Send = 1;
t->internal.client[index].wsConnected = 1;
t->internal.client[index].debug.websocketConnectCount++;
} else {
jsonInternalSetWSServerError(t->internal.client[index].wsConnect.Status, t);
}

}
}
else /*if (t->internal.client[index].wsConnected)*/ {

Expand All @@ -306,37 +338,59 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)

// NOTE: A lot of things cause the parsing to bonk with no response to the client[index].
// We might want to generate an error response to the client instead.

UDINT existingLen = t->internal.client[index].tcpStream.IN.PAR.pReceiveData - t->internal.client[index].pReceiveData;
UDINT totalLen = t->internal.client[index].tcpStream.OUT.ReceivedDataLength + existingLen;

// Decode frame
t->internal.client[index].wsDecode.pFrame = t->internal.client[index].tcpStream.IN.PAR.pReceiveData;
jsonWSDecode(&t->internal.client[index].wsDecode);

// Note: even though the header may be greater than 8 bytes, the payload length information will be a contained within the first 8
if(totalLen >= 8) {
t->internal.client[index].wsDecode.pFrame = t->internal.client[index].pReceiveData;//t->internal.client[index].tcpStream.IN.PAR.pReceiveData;
jsonWSDecode(&t->internal.client[index].wsDecode);
}
else {
t->internal.client[index].tcpStream.IN.PAR.pReceiveData = t->internal.client[index].pReceiveData + totalLen;
t->internal.client[index].tcpStream.IN.PAR.MaxReceiveLength = t->BufferSize - totalLen;
t->internal.client[index].debug.tooSmallCount++;
jsonInternalSetWSServerError(JSON_ERR_TCP_FRAGMENT, t);
continue;
}

// Check frame
// NOTE: For now, set some errors if we get an unexpected frame
// Might need to replace these with an error response to the client
if (t->internal.client[index].wsDecode.Status != 0) { jsonInternalSetWSServerError(t->internal.client[index].wsDecode.Status, t); continue; }
if (t->internal.client[index].wsDecode.FIN == 0) { jsonInternalSetWSServerError(JSON_ERR_WS_FRAGMENT, t); continue; }
// TODO: We need to use this (FIN) to reconstruct messages. With TLS messages are split up frequently and is unusable without this feature
//if (t->internal.client[index].wsDecode.FIN == 0) { jsonInternalSetWSServerError(JSON_ERR_WS_FRAGMENT, t); continue; }
if (t->internal.client[index].wsDecode.RSV != 0) { jsonInternalSetWSServerError(JSON_ERR_WS_RSV, t); continue; }
if (t->internal.client[index].wsDecode.OpCode != JSON_WS_OPCODE_TEXT) { jsonInternalSetWSServerError(JSON_ERR_WS_OPCODE, t); continue; }
if (t->internal.client[index].wsDecode.MASK == 0) { jsonInternalSetWSServerError(JSON_ERR_WS_MASK, t); t->internal.client[index].tcpStream.IN.CMD.Close = 1; continue; }
if (t->internal.client[index].wsDecode.OpCode != JSON_WS_OPCODE_TEXT
&& t->internal.client[index].wsDecode.FIN == 1
&& t->internal.client[index].recieveDataBufferLen == 0) { jsonInternalSetWSServerError(JSON_ERR_WS_OPCODE, t); continue; }
//if (t->internal.client[index].wsDecode.MASK == 0) { jsonInternalSetWSServerError(JSON_ERR_WS_MASK, t); t->internal.client[index].tcpStream.IN.CMD.Close = 1; continue; }

// Check WS frame length against received TCP message length
t->internal.client[index].excessDataLength = t->internal.client[index].tcpStream.OUT.ReceivedDataLength - t->internal.client[index].wsDecode.FrameLength;
t->internal.client[index].excessDataLength = totalLen - t->internal.client[index].wsDecode.FrameLength;

if (t->internal.client[index].excessDataLength == 0) {

t->internal.client[index].tcpStream.IN.PAR.pReceiveData = t->internal.client[index].pReceiveData;
t->internal.client[index].tcpStream.IN.PAR.MaxReceiveLength = t->BufferSize;

t->internal.client[index].debug.justRightCount++;

} else if (t->internal.client[index].excessDataLength > 0) {

t->internal.client[index].tcpStream.IN.PAR.pReceiveData = t->internal.client[index].pReceiveData;
t->internal.client[index].tcpStream.IN.PAR.MaxReceiveLength = t->BufferSize;

t->internal.client[index].debug.tooBigCount++;

} else {

t->internal.client[index].tcpStream.IN.PAR.pReceiveData = t->internal.client[index].pReceiveData + totalLen;
t->internal.client[index].tcpStream.IN.PAR.MaxReceiveLength = t->BufferSize - totalLen;
t->internal.client[index].debug.tooSmallCount++;
jsonInternalSetWSServerError(JSON_ERR_TCP_FRAGMENT, t);
continue;

continue;
}


Expand All @@ -352,16 +406,35 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)
// Unmask data - NOTE: Make this a public FUB
UDINT i;
char *pPayloadData = (char*)t->internal.client[index].wsDecode.pPayloadData;
char *pRecieveBuffer = &((char*)t->internal.client[index].pRecieveDataBuffer)[t->internal.client[index].recieveDataBufferLen];
for (i = 0; i < t->internal.client[index].wsDecode.PayloadLength; i++) {
pPayloadData[i] = pPayloadData[i] ^ t->internal.client[index].wsDecode.MaskingKey[i % 4];
}
for (i = 0; i < t->internal.client[index].wsDecode.PayloadLength; i++) {
pRecieveBuffer[i] = pPayloadData[i];
}
t->internal.client[index].recieveDataBufferLen += t->internal.client[index].wsDecode.PayloadLength;
((char*)t->internal.client[index].pRecieveDataBuffer)[t->internal.client[index].recieveDataBufferLen] = '\0';

if(t->internal.client[index].wsDecode.FIN == 0) {
// We have recieved a partial message
// So let us wait for the full message :)
continue;
}

// Parse data - NOTE: Make this a private function
// Expect {"type":"read"|"write","data":["varName","varName"]|{}}
// Need type in one string and pointer to data string
char *pMessageData = (char*)t->internal.client[index].wsDecode.pPayloadData;
char *pMessageData = (char*)t->internal.client[index].pRecieveDataBuffer;
STRING requestType[7+1], data[4+1];
UDINT dataLength = t->internal.client[index].recieveDataBufferLen;

// If we get here
// We have used the buffered message data
// Clear it
t->internal.client[index].recieveDataBufferLen = 0;
//((char*)t->internal.client[index].pRecieveDataBuffer)[0] = '\0';

// {
pMessageData = skip(pMessageData);
if (*pMessageData != '{') { jsonInternalSetWSServerError(JSON_ERR_PARSE, t); continue; }
Expand Down Expand Up @@ -412,7 +485,7 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)

// Determine data length
// Data length = total payload length - message beginning length '{type...' - message ending length '}'
UDINT dataLength = t->internal.client[index].wsDecode.PayloadLength - ((UDINT)pMessageData - (UDINT)pPayloadData) - 1;
dataLength = dataLength - ((UDINT)pMessageData - t->internal.client[index].pRecieveDataBuffer) - 1;

// Replace ending '}' with a null.
pMessageData[dataLength] = 0;
Expand All @@ -421,7 +494,7 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)
// This can be put into the jsonRead or jsonWrite functions

//UDINT debugDataLength = strlen(pMessageData);


// Process request - NOTE: Make this a private function
//--------------------------------------------
Expand Down Expand Up @@ -512,6 +585,7 @@ void jsonWebSocketServer(struct jsonWebSocketServer* t)

//i = 0;//temp for debug
//char *pResponseData = (char*)t->internal.client[index].messageBuffer.pData;//temp for debug


}// Connected

Expand Down