ArduinoWebsocketServer/WebSocket.cpp at master · ejeklint/ArduinoWebsocketServer · GitHub

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#include "WebSocket.h"

#include "sha1.h"

#include "Base64.h"

//#define DEBUG 1

struct Frame {

bool isMasked;

bool isFinal;

byte opcode;

byte mask[4];

byte length;

char data[64];

} frame;

WebSocketServer::WebSocketServer(const char *urlPrefix, int inPort, byte maxConnections) :

m_server(inPort),

m_socket_urlPrefix(urlPrefix),

m_maxConnections(maxConnections),

m_connectionCount(0)

{

m_connections = new WebSocket*[ m_maxConnections ];

for( byte x=0; x < m_maxConnections; x++ )

m_connections[x] = NULL;

onConnect = NULL;

onData = NULL;

onDisconnect = NULL;

}

void WebSocketServer::registerConnectCallback(Callback *callback) {

onConnect = callback;

}

void WebSocketServer::registerDataCallback(DataCallback *callback) {

onData = callback;

}

void WebSocketServer::registerDisconnectCallback(Callback *callback) {

onDisconnect = callback;

}

void WebSocketServer::begin() {

m_server.begin();

}

byte WebSocketServer::connectionCount()

{

return m_connectionCount;

}

void WebSocketServer::send( char *data, byte length )

{

m_server.write((uint8_t) 0x81); // Txt frame opcode

m_server.write((uint8_t) length); // Length of data

m_server.write( (const uint8_t *)data, length );

}

void WebSocketServer::listen() {

// First check existing connections:

for( byte x=0; x < m_maxConnections; x++ )

{

if( !m_connections[x] )

continue;

WebSocket *s = m_connections[x];

if( !s->isConnected() )

{

m_connectionCount--;

delete s;

m_connections[x] = NULL;

continue;

}

s->listen();

}

EthernetClient cli = m_server.available();

if( !cli )

return;

// Find a slot:

for( byte x=0; x < m_maxConnections; x++ )

{

if( m_connections[x] )

continue;

WebSocket *s = new WebSocket(this, cli);

m_connections[x] = s;

m_connectionCount++;

#ifdef DEBUG

Serial.println(F("Websocket client connected."));

#endif

return;

}

// No room!

#ifdef DEBUG

Serial.println(F("Cannot accept new websocket client, maxConnections reached!"));

#endif

cli.stop();

}

WebSocket::WebSocket( WebSocketServer *server, EthernetClient cli ) :

m_server(server),

client(cli)

{

if( doHandshake() )

{

state = CONNECTED;

if( m_server->onConnect )

m_server->onConnect(*this);

return;

}

disconnectStream();

}

void WebSocket::listen()

{

if( !client.available() )

return;

if( !getFrame() )

// Got unhandled frame, disconnect

disconnectStream();

}

bool WebSocket::isConnected() {

return (state == CONNECTED);

}

void WebSocket::disconnectStream() {

#ifdef DEBUG

Serial.println(F("Disconnecting"));

#endif

state = DISCONNECTED;

if( m_server->onDisconnect )

m_server->onDisconnect(*this);

client.flush();

delay(1);

client.stop();

}

bool WebSocket::doHandshake() {

char temp[128];

char key[80];

char bite;

bool hasUpgrade = false;

bool hasConnection = false;

bool isSupportedVersion = false;

bool hasHost = false;

bool hasKey = false;

byte counter = 0;

while ((bite = client.read()) != -1) {

temp[counter++] = bite;

if (counter > 2 && (bite == '\n' || counter >= 127)) { // EOL got, or too long header. temp should now contain a header string

temp[counter - 2] = 0; // Terminate string before CRLF

#ifdef DEBUG

Serial.print("Got header: ");

Serial.println(temp);

#endif

// Ignore case when comparing and allow 0-n whitespace after ':'. See the spec:

// http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html

if (!hasUpgrade && strstr_P(temp, PSTR("Upgrade: "))) {

// OK, it's a websockets handshake for sure

hasUpgrade = true;

} else if (!hasConnection && strstr_P(temp, PSTR("Connection: "))) {

hasConnection = true;

} else if (!hasHost && strstr_P(temp, PSTR("Host: "))) {

hasHost = true;

} else if (!hasKey && strstr_P(temp, PSTR("Sec-WebSocket-Key: "))) {

hasKey = true;

strtok(temp, " ");

strcpy(key, strtok(NULL, " "));

} else if (!isSupportedVersion && strstr_P(temp, PSTR("Sec-WebSocket-Version: ")) && strstr_P(temp, PSTR("13"))) {

isSupportedVersion = true;

}

counter = 0; // Start saving new header string

}

// Assert that we have all headers that are needed. If so, go ahead and

// send response headers.

if (hasUpgrade && hasConnection && isSupportedVersion && hasHost && hasKey) {

strcat_P(key, PSTR("258EAFA5-E914-47DA-95CA-C5AB0DC85B11")); // Add the omni-valid GUID

Sha1.init();

Sha1.print(key);

uint8_t *hash = Sha1.result();

base64_encode(temp, (char*)hash, 20);

char buf[132];

snprintf_P( buf, sizeof(buf), PSTR("HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: %s\r\n\r\n"), temp );

client.print( buf );

} else {

// Nope, failed handshake. Disconnect

#ifdef DEBUG

Serial.print(F("Handshake failed! Upgrade:"));

Serial.print( hasUpgrade );

Serial.print(F(", Connection:"));

Serial.print( hasConnection );

Serial.print(F(", Host:"));

Serial.print( hasHost );

Serial.print(F(", Key:"));

Serial.print( hasKey );

Serial.print(F(", Version:"));

Serial.println( isSupportedVersion );

#endif

return false;

}

return true;

}

bool WebSocket::getFrame() {

byte bite;

// Get opcode

bite = client.read();

frame.opcode = bite & 0xf; // Opcode

frame.isFinal = bite & 0x80; // Final frame?

// Determine length (only accept <= 64 for now)

bite = client.read();

frame.length = bite & 0x7f; // Length of payload

if (frame.length > 64) {

#ifdef DEBUG

Serial.print(F("Too big frame to handle. Length: "));

Serial.println(frame.length);

#endif

client.write((uint8_t) 0x08);

client.write((uint8_t) 0x02);

client.write((uint8_t) 0x03);

client.write((uint8_t) 0xf1);

return false;

}

// Client should always send mask, but check just to be sure

frame.isMasked = bite & 0x80;

if (frame.isMasked) {

frame.mask[0] = client.read();

frame.mask[1] = client.read();

frame.mask[2] = client.read();

frame.mask[3] = client.read();

}

// Clear any frame data that may have come previously

memset(frame.data, 0, sizeof(frame.data)/sizeof(char));

// Get message bytes and unmask them if necessary

for (int i = 0; i < frame.length; i++) {

if (frame.isMasked) {

frame.data[i] = client.read() ^ frame.mask[i % 4];

} else {

frame.data[i] = client.read();

}

// Frame complete!

if (!frame.isFinal) {

// We don't handle fragments! Close and disconnect.

#ifdef DEBUG

Serial.println(F("Non-final frame, doesn't handle that."));

#endif

client.print((uint8_t) 0x08);

client.write((uint8_t) 0x02);

client.write((uint8_t) 0x03);

client.write((uint8_t) 0xf1);

return false;

}

switch (frame.opcode) {

case 0x01: // Txt frame

// Call the user provided function

if( m_server->onData )

m_server->onData(*this, frame.data, frame.length);

break;

case 0x08:

// Close frame. Answer with close and terminate tcp connection

// TODO: Receive all bytes the client might send before closing? No?

#ifdef DEBUG

Serial.println(F("Close frame received. Closing in answer."));

#endif

client.write((uint8_t) 0x08);

return false;

break;

default:

// Unexpected. Ignore. Probably should blow up entire universe here, but who cares.

#ifdef DEBUG

Serial.println(F("Unhandled frame ignored."));

#endif

return false;

break;

}

return true;

}

bool WebSocket::send(char *data, byte length)

{

if( state != CONNECTED )

{

#ifdef DEBUG

Serial.println(F("No connection to client, no data sent."));

#endif

return false;

}

client.write((uint8_t) 0x81); // Txt frame opcode

client.write((uint8_t) length); // Length of data

client.write( (const uint8_t *)data, length );

return true;

}

ArduinoWebsocketServer/WebSocket.cpp at master · ejeklint/ArduinoWebsocketServer · GitHub

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