sysdis-tp/lib.c

#include "lib.h"


int debug(const char* tag, const char* msg){

	/* (1) Get number of characters to add */
	int diff = DEBUG_LEN - strlen(msg) - strlen(tag) - 3;

	/* (2) print msg */
	printf("[%s] %s", tag, msg);

	/* (3) print missing characters */
	for( ; diff >= 0 ; diff-- )
		printf(".");

	return 1;
}






int xbind(const int port){

	/* [0] Initialization
	=========================================================*/
	int xsocket, bound;
	static struct sockaddr_in addr;
	

	/* [1] Create xsocket
	=========================================================*/
	/* (1) Create UPD xsocket */
	xsocket = socket(AF_INET, SOCK_DGRAM, 0);
	DEBUG&& debug("xbind", "creating server socket");

	/* (r2-) Manage error */
	if( xsocket == -1 ){
		DEBUG&& printf("error\n");
		return -1;
	}

	DEBUG&& printf("done\n");

	/* [2] Set xsocket address information
	=========================================================*/
	/* (1) Reset values */
	bzero(&addr, sizeof(struct sockaddr_in));

	/* (2) Set xsocket addr */
	addr.sin_family      = AF_INET;
	addr.sin_port        = htons(port);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	


	/* [3] Bind to port
	=========================================================*/
	/* (1) Bind and return -1 if error */
	bound = bind(xsocket, (struct sockaddr*)&addr, sizeof(addr));
	DEBUG&& debug("xbind", "binding socket to port");
	
	/* (2) Manage error */
	if( bound == -1 ){
		DEBUG&& printf("error\n");
		return -1;
	}

	DEBUG&& printf("done\n");
	

	/* [4] Return xsocket
	=========================================================*/
	return xsocket;
}






int xconnect(const char* hostname, const int port, struct sockaddr_in* serv){

	/* [0] Initialization
	=========================================================*/
	int xsocket, bound;
	struct hostent *host; // data found by lookup
	

	/* [1] Create xsocket
	=========================================================*/
	/* (1) Create UPD xsocket */
	xsocket = socket(AF_INET, SOCK_DGRAM, 0);
	DEBUG&& debug("xconnect", "creating client socket");

	/* (r2-) Manage error */
	if( xsocket == -1 ){
		DEBUG&& printf("error\n");
		return -1;
	}

	DEBUG&& printf("done\n");


	/* [2] Get information by hostname
	=========================================================*/
	/* (1) Process */
	host = gethostbyname(hostname);
	DEBUG&& debug("xconnect", "fetch info by hostname");

	/* (2) Manage error */
	if( host == NULL ){
		DEBUG&& printf("error\n");
		return -1;
	}

	DEBUG&& printf("found\n");
	
	

	/* [3] Set server useful information from fetched info
	=========================================================*/
	/* (1) Reset values */
	bzero(serv, sizeof(struct sockaddr_in));
	DEBUG&& debug("xconnect", "building server info");

	/* (2) Set server info (ipv4, port) */
	serv->sin_family      = AF_INET;
	serv->sin_port        = htons(port);

	/* (3) Copy server address */
	memcpy( &serv->sin_addr.s_addr, host->h_addr, host->h_length);
	
	DEBUG&& printf("built\n");


	// return socket
	return xsocket;
}








int xlisten(const int xsocket, struct sockaddr_in *client, char* buffer, int bufsize){

	/* [1] Wait for message through xsocket
	=========================================================*/
	/* (1) Useful data + memory allocation */
	socklen_t sock_len = sizeof(struct sockaddr_in);
	buffer = (char*) realloc(buffer, sizeof(char) * bufsize );
	
	/* (2) Listen */
	DEBUG&& debug("xlisten", "waiting for data");
	int read = recvfrom(xsocket, buffer, bufsize / sizeof(char) + sizeof(char), 0, (struct sockaddr*) client, &sock_len);

	/* (3) Manage error */
	if( read == -1 ){
		DEBUG&& printf("error\n");
		return -1;
	}

	DEBUG&& printf("received\n");

	printf("[xlisten:received] '%s'\n", buffer);


	/* [2] Return number of read characters
	=========================================================*/
	return read;
}






int xsend(const int xsocket, char* buffer, struct sockaddr_in* target){

	/* [1] Send buffer (message) to target
	=========================================================*/
	/* (1) Useful data */
	size_t addr_len = sizeof(struct sockaddr_in);

	/* (2) Send data */
	DEBUG&& debug("xsend", "sending data");
	int sent = sendto(xsocket, buffer, strlen(buffer)+1, 0, (struct sockaddr*) target, addr_len);
	
	/* (3) Manage error */
	if( sent == -1 ){
		DEBUG&& printf("error\n");
		return -1;
	}
	
	DEBUG&& printf("sent\n");


	printf("[xsend:sent] '%s'\n", buffer);


	/* [2] Return number of sent characters
	=========================================================*/
	return sent;
}