Server.c

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// This article and all its includes are licenced under LGPL
// GPL: http://www.gnu.org/copyleft/lesser.html
// SRC: http://www.organicdesign.co.nz/server.c

#define svrDELAY 0         // normal operation is 0 for no delay
#define svrPAKSIZE 128     // keep packet-size small for non-multithreaded design
#define svrPAKMAX  16384   // maximum packet size to allow for variable pak size at runtime
#define svrBUFSIZE 4096    // dictates max message size
#define svrMAXCLIENTS 1000 // used by listen()
#ifndef __WIN32__
#define WSAGetLastError() errno
#endif

// Socket structures, globals and prototypes
void server();
int serverInit();
int serverExit();
int nonblocking(int socket);
fd_set *fdsetInit(int fd);
fd_set fdset;
int sock,fd;
struct sockaddr_in addr;
struct timeval to;
unsigned long int sockopt_on;

// Client/Stream info structure, globals and prototypes
char *pBuf;                // Buffer to read/write data packets
const char *term = "\r\n\r\n";
typedef struct siStruct {
	int fd;                // File-descriptor for this stream
	char *iBuf, *oBuf;     // Message buffers for this stream
	int iPtr;              // Index into input-buffer for next packet to start at
	int tPtr;              // Index into term (atomised strcmp incase terminator spans packet-boundary)
	int oPtr;
	} streamInfo;
void client();
int streamOpen(int fd,char *resource);
void streamClose(streamInfo *stream);
void streamProcess(streamInfo *stream);


// Initialise socket listening on specified port
int serverInit() {

	#if __WIN32__
	WSADATA wsaData;
	if (WSAStartup(MAKEWORD(2,0),&wsaData)!=0) logErr("WSAStartup() failed!");
	#endif

	// Set up structures for socket & select
	sockopt_on = 1;
	int szAddr = sizeof(struct sockaddr_in);
	memset((char*)&addr, 0, szAddr); // zero the struct
	addr.sin_family = AF_INET;
	addr.sin_port = htons(port);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	errno = 0;

	// Do the usual socket polava: create,options,bind,listen
	if ((sock = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP))<0)
		logErrNum("init/socket() failed returning %d",WSAGetLastError());
	if (setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(char*)&sockopt_on,sizeof(int))<0)
		logErrNum("init/setsockopt() failed returning %d",WSAGetLastError());
	if (bind(nonblocking(sock),(struct sockaddr*)&addr,szAddr)<0)
		logErrNum("init/bind() failed returning %d",WSAGetLastError());
	if (listen(sock,svrMAXCLIENTS)<0)
		logErrNum("init/listen() failed returning %d",WSAGetLastError());

	if (WSAGetLastError() == 0) {
		char *msg = malloc(100);
		sprintf(msg,"Daemon \"%s\" started successfully and serving on port %d.",peer,port);
		logAdd(msg);
		free(msg);
		}
	else {
		logAdd("Server failed to start!");
		return WSAGetLastError();
		}

	// Globals for server() and client() quantum-functions
	pBuf = malloc(svrPAKMAX);
	*nodeState(nodeSERVER,0) = &server;
	nodeSetValue(nodeSERVER,nodeCODE,nodeTRUE);

	return 0;	
	}


// Perform any cleanup for socket
int serverExit() {
	free(pBuf);
	// todo: close streams and free buffers etc
	#if __WIN32__
	WSACleanup();
	#endif
	return WSAGetLastError();
	}


// make the passed socket non-blocking so accept() returns straight away for multiplexed model
// - if no incoming requests, returns EAGAIN or EWOULDBLOCK state
int nonblocking(int socket) {
	#if __WIN32__
	ioctlsocket(socket,FIONBIO,&sockopt_on);
	#else
	fcntl(socket,F_SETFL,fcntl(socket,F_GETFL)|O_NONBLOCK);
	#endif
	return socket;
	}


// Return pointer to fdset filled with passed file-descriptor ready for a select() call
fd_set *fdsetInit(int fd) {
	FD_ZERO(&fdset);
	FD_SET(fd,&fdset);
	to.tv_sec = to.tv_usec = svrDELAY;
	return &fdset;
	}


// Process message in iBuf which should be a complete HTTP GET request
// - iPtr is put back to 0 so next message fills from start of iBuf
void streamProcess(streamInfo *stream) {
	char *rqst, *end, *msg = stream->iBuf;
	if (strncmp("GET /",msg,5)==0) {

		// Extract request path & query-string
		rqst = end = msg+4;
		while(*++end > ' ');
		*end = '\0';
		printf("Request:\"%s\"\n",rqst);

		// Exit if /stop requested
		if (strcmp("/stop",rqst)==0) nodeExit();

		// Send test response back
		send(stream->fd,"HTTP/1.1 200 OK\r\nDate: Mon, 31 Jul 2006 22:27:14 NZST\r\nContent-Type: text/html\r\nConnection: keep-alive\r\nContent-Length: 9\r\n\r\nStink eh?",134,0);
		}
	else {
		send(stream->fd,"HTTP/1.1 200 OK\r\nDate: Mon, 31 Jul 2006 22:27:14 NZST\r\nContent-Type: text/html\r\nConnection: keep-alive\r\nContent-Length: 9\r\n\r\nNo GET!!!",134,0);
		logAdd("Peerd only supports GET requests currently!");
		}
	stream->iPtr = 0; // reset iPtr ready for next message
	}


// Create new client-node and streamInfo structure from passed file-descriptor
// - if fd is NULL, then try and create one by resolving the resource string
void streamOpen(int fd, char *resource) {
	if (fd == NULL) {
		// if resource is /^[./]/ then its a file
		// - file will have different packet size etc
		// - may need to include &recv/&read etc in streamInfo struct
		}
	if (fd < 0) return logErrMsg("Couldn't open resource \"%s\"",resource);
	logAddNum("New connection: Stream%d.",fd);
	// Create new streamInfo structure and allocate buffers
	streamInfo *stream = malloc(sizeof(streamInfo));
	stream->fd = fd;
	stream->iBuf = malloc(svrBUFSIZE);
	stream->oBuf = malloc(svrBUFSIZE);
	stream->iPtr = stream->oPtr = stream->tPtr = 0;

	// Create new client-node in clients-loop and add the new streamInfo
	node nc = nodeGetValue(nodeCLIENTS,nodeLOOP);
	nc = nodeLoopInsert(nc,0);
	nodeSetValue(nodeCLIENTS,nodeLOOP,nc);
	nodeSetValue(nc,nodeCODE,nodeTRUE);
	*nodeState(nc,0) = &client;
	*nodeState(nc,nodeSTREAM) = stream;
	}


// Close the passed stream, free its resources and remove from clients-loop
void streamClose(streamInfo *stream) {
	printf("Stream%d closed.\n",stream->fd);
	//nodeLoopRemove(this); // NOTE: reduction not handling PREV
	free(stream->iBuf);
	free(stream->oBuf);
	free(stream);
	}


// Each of the stream nodes points to this function in its State
void client() {

	// Get pointer to the streamInfo structure in current nodal context (this)
	streamInfo *stream = *nodeState(this, nodeSTREAM);
	fd = stream->fd;
	char *iBuf = stream->iBuf, *oBuf = stream->oBuf;
	int n, i = 0;

	// If any data to recieve, read a packet
	if (select(fd+1,fdsetInit(fd),NULL,NULL,&to)>0) {
		if ((n = recv(fd,pBuf,svrPAKSIZE,0)) > 0) {
			// Some bytes were read, append to current message (loop last packet if msg too big)
			if (stream->iPtr > svrBUFSIZE-svrPAKSIZE) stream->iPtr -= svrPAKSIZE;
			while (n--)  // Append current msg, for each complete msg, process it & reset iPtr
				if ((iBuf[stream->iPtr++] = pBuf[i++]) != term[stream->tPtr++]) stream->tPtr = 0;
				else if (term[stream->tPtr] == 0) streamProcess(stream);
			}
		else if (n == 0) streamClose(stream); // Zero bytes were read, do orderly termination
		else logErrNum("client/recv() failed returning %d",WSAGetLastError());
		}

	// Data to send?
	//if (select(fd+1,NULL,fdsetInit(fd),NULL,&to)>0) {
		// write a packet from outbuf
		//int len = svrPAKSIZE; // or less
		//if (send(fd,oBuf+oPtr,len,0)<0) logErr("send() failed!");
	//	}

	}


// Function called by each stream-node in network's reduction loop
// - Checks if any new connections waiting on listening socket,
//   if so accept and call streamOpen() with new file-descriptor
void server() {
	if (select(sock+1,fdsetInit(sock),NULL,NULL,&to)>0)
		if ((fd = nonblocking(accept(sock,NULL,NULL)))>0) streamOpen(fd,NULL);
		else logErrNum("server/accept() failed returning %d",WSAGetLastError());
	}