Socket - Client-Server

//*************************sercer.c*********************************

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#define SERVER_BANNER "Introduceti un numar si voi spune daca este par sau impar !"

#define MAX_CLIENTS 5

//Primeste un mesaj de eroare si il printeaza

void error(char *msg)

{

perror(msg);

exit(1);

}

int main(int argc, char *argv[])

{

int sockfd, newsockfd, portno, clilen;

char buffer[256];

struct sockaddr_in serv_addr, cli_addr;

int n, i, j;

fd_set read_fds; //fd_set folosit in select()

fd_set tmp_fds; //fd_set folosit temporar

int fdmax; //nr maxim de file descriptori

if (argc < 2) {

fprintf(stderr,"Usage : %s portn", argv[0]);

exit(1);

}

//golim read_fds

FD_ZERO(&read_fds);

FD_ZERO(&tmp_fds);

sockfd = socket(AF_INET, SOCK_STREAM, 0);

if (sockfd < 0)

error("ERROR opening socket");

portno = atoi(argv[1]);

memset((char *) &serv_addr, 0, sizeof(serv_addr));

serv_addr.sin_family = AF_INET;

serv_addr.sin_addr.s_addr = INADDR_ANY; // foloseste adresa IP a masinii

serv_addr.sin_port = htons(portno);

if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(struct sockaddr)) < 0)

error("ERROR on binding");

listen(sockfd, MAX_CLIENTS);

//adaugam noul file descriptor in multimea read_fds

FD_SET(sockfd, &read_fds);

fdmax = sockfd;

// main loop

for(;;) {

tmp_fds = read_fds;

if (select(fdmax + 1, &tmp_fds, NULL, NULL, NULL) == -1)

error("ERROR in select");

for(i = 0; i <= fdmax; i++) {

if (FD_ISSET(i, &tmp_fds)) {

if (i == sockfd) {

// o noua conexiune

clilen = sizeof(cli_addr);

if ((newsockfd = accept(sockfd, (struct sockaddr *)&cli_addr, &clilen)) == -1) {

error("ERROR in accept");

} else {

FD_SET(newsockfd, &read_fds);

if (newsockfd > fdmax) {

fdmax = newsockfd;

}

printf("selectserver: new connection from %sn ", inet_ntoa(cli_addr.sin_addr));

//trimitem banner

n = send(newsockfd, SERVER_BANNER, strlen(SERVER_BANNER), 0);

if (n < 0)

error("ERROR writing to socket");

}

} else {

// am primit date