#include <stdio.h>
#include <string.h> //strlen
#include <stdlib.h>
#include <errno.h>
#include <unistd.h> //close
#include <arpa/inet.h> //close
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/time.h> //FD_SET, FD_ISSET, FD_ZERO macros
#define TRUE 1
#define FALSE 0
#define PORT 8888
int
main(
int
argc ,
char
*argv[])
{
int
opt = TRUE;
int
master_socket , addrlen , new_socket , client_socket[30] ,
max_clients = 30 , activity, i , valread , sd;
int
max_sd;
struct
sockaddr_in address;
char
buffer[1025];
fd_set readfds;
char
*message =
"ECHO Daemon v1.0 \r\n"
;
for
(i = 0; i < max_clients; i++)
{
client_socket[i] = 0;
}
if
( (master_socket = socket(AF_INET , SOCK_STREAM , 0)) == 0)
{
perror
(
"socket failed"
);
exit
(EXIT_FAILURE);
}
if
( setsockopt(master_socket, SOL_SOCKET, SO_REUSEADDR, (
char
*)&opt,
sizeof
(opt)) < 0 )
{
perror
(
"setsockopt"
);
exit
(EXIT_FAILURE);
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons( PORT );
if
(bind(master_socket, (
struct
sockaddr *)&address,
sizeof
(address))<0)
{
perror
(
"bind failed"
);
exit
(EXIT_FAILURE);
}
printf
(
"Listener on port %d \n"
, PORT);
if
(listen(master_socket, 3) < 0)
{
perror
(
"listen"
);
exit
(EXIT_FAILURE);
}
addrlen =
sizeof
(address);
puts
(
"Waiting for connections ..."
);
while
(TRUE)
{
FD_ZERO(&readfds);
FD_SET(master_socket, &readfds);
max_sd = master_socket;
for
( i = 0 ; i < max_clients ; i++)
{
sd = client_socket[i];
if
(sd > 0)
FD_SET( sd , &readfds);
if
(sd > max_sd)
max_sd = sd;
}
activity = select( max_sd + 1 , &readfds , NULL , NULL , NULL);
if
((activity < 0) && (
errno
!=EINTR))
{
printf
(
"select error"
);
}
if
(FD_ISSET(master_socket, &readfds))
{
if
((new_socket = accept(master_socket,
(
struct
sockaddr *)&address, (socklen_t*)&addrlen))<0)
{
perror
(
"accept"
);
exit
(EXIT_FAILURE);
}
printf
("New connection , socket fd is %d , ip is : %s , port : %d
\n" , new_socket , inet_ntoa(address.sin_addr) , ntohs
(address.sin_port));
if
( send(new_socket, message,
strlen
(message), 0) !=
strlen
(message) )
{
perror
(
"send"
);
}
puts
(
"Welcome message sent successfully"
);
for
(i = 0; i < max_clients; i++)
{
if
( client_socket[i] == 0 )
{
client_socket[i] = new_socket;
printf
(
"Adding to list of sockets as %d\n"
, i);
break
;
}
}
}
for
(i = 0; i < max_clients; i++)
{
sd = client_socket[i];
if
(FD_ISSET( sd , &readfds))
{
if
((valread = read( sd , buffer, 1024)) == 0)
{
getpeername(sd , (
struct
sockaddr*)&address , \
(socklen_t*)&addrlen);
printf
(
"Host disconnected , ip %s , port %d \n"
,
inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
close( sd );
client_socket[i] = 0;
}
else
{
buffer[valread] =
'\0'
;
send(sd , buffer ,
strlen
(buffer) , 0 );
}
}
}
}
return
0;
}