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/*********************************************************************
/ PROGRAM: icu2 (main.c) Server Program
/ AUTHOR: Nathan Buggia & Ruben Kim
/ DATE: May 3, 1998
/*********************************************************************/
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <errno.h>
//- - - - - - - - - - - - - - - - - - - - #define's
#define ICU2_PORT 3033
#define LISTEN_QUEUE_SIZE 5
#define MAX_CONNECTIONS 50
#define IO_BUFFER 255
#define CLIENTFD_INIT -1
//- - - - - - - - - - - - - - - - - - - - global vars
char CONNECTION_REQUEST[5] = "+EST"; // client requests connection
char ACCEPT_CONNECTION[5] = "+CON"; // server accepts conneciton
char NOT_ACCEPTED[5] = "-NOA"; // server is full and did not accept connection
char DISCONNECTING[5] = "-DIS"; // client requeting to disconnect
int clientfd[MAX_CONNECTIONS]; // array of connected clients' sockfd's
int current_connections = 0; // number of clients currently connected
int listenfd; // fd of the listening socket.
int sockfd; // fd of the syncronus socket.
struct sockaddr_in address; // sockfd's struct object.
char input[IO_BUFFER], output[IO_BUFFER]; // input and output buffers.
char *temp;
char tempbuf[6];
int i;
//- - - - - - - - - - - - - - - - - - - - int main()
int main(){
listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(&address, 0, sizeof(address));
address.sin_family = AF_INET;
address.sin_addr.s_addr = htonl(INADDR_ANY);
address.sin_port = htons(ICU2_PORT);
bind(listenfd, (struct sockaddr *)&address, sizeof(address));
listen(listenfd, LISTEN_QUEUE_SIZE);
for(i = 0; i <= MAX_CONNECTIONS-1; i++) {
clientfd[i] = CLIENTFD_INIT;
}/* endfor */
for(;;){
sockfd = accept(listenfd, (struct sockaddr *) NULL, NULL);
read(sockfd, &input, IO_BUFFER);
printf("\n\nServer receives: %s\n",input);
if( !strncmp(input, CONNECTION_REQUEST, 4) ){ // if it is a connection request.
printf("Server has a connection request.\n");
if( current_connections < MAX_CONNECTIONS ){
printf("There is room for another connection.\n");
clientfd[current_connections] = sockfd;
current_connections++;
write(sockfd, &ACCEPT_CONNECTION, IO_BUFFER);
}else{
printf("Server is full!\n");
write(sockfd, &NOT_ACCEPTED, IO_BUFFER);
}
}
/* Disconnect request from client */
else if( !strncmp(input, DISCONNECTING, 4) ) {
printf("Server received a disconnect request with sockfd == ");
sockfd = -1;
sscanf( input, "%5c%d", tempbuf, &sockfd);
printf( "%d\n", sockfd);
if(sockfd == -1) {
printf("Error while reading -DIS...\n");
printf("This data will be ignored.\n");
}/* endif */
else {
printf("Successful -DIS_# reading\n");
while( clientfd[i] != sockfd && i <= MAX_CONNECTIONS-1 ) {
i++;
}
clientfd[i] = CLIENTFD_INIT;
// close(sockfd);
}/* endelse */
}/* endif */
/* Anything else will be sent to all connected users */
else{
printf("Printing this out to all clients: \n");
printf("\t%s\n", input);
/* writing input to all active sockets */
for(i = 0; i <= MAX_CONNECTIONS-1; i++) {
sockfd = clientfd[i];
if( sockfd != CLIENTFD_INIT) {
write(sockfd, &input, IO_BUFFER);
}/* endif */
}/* endfor */
}/* endelse */
}
return 0;
}