Hi, I was wondering how to make client connect to multiple servers.
I decided to use select for this but I don't see how it should work well like in the server.
Pseudocode:
void connect_to_server(char argv[]) {
if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == ERROR) {
perror("socket problem: ");
exit(1);
}
if ((hostp = gethostbyname(argv)) == 0) {
} else {
memset(&serveraddr, 0, sizeof (serveraddr));
serveraddr.sin_family = AF_INET;
memcpy(&serveraddr.sin_addr, hostp->h_addr, hostp->h_length);
serveraddr.sin_port = htons(portnumber);
if (bind(sock, (struct sockaddr *) & clientaddr, sizeof (clientaddr)) == ERROR) {;
}
process();
}
}
/**
* process we want to connect to server in tcp and udp selective function to
* get warnings from the server and statistics
* in tcp. This makes it easier for us to clean up wether the server has shutdown
* or not.
*
* @globl sock the given socket when connected
* @globl new the udp socketconnection
*/
void *process() {
fd_set read_set;
struct sockaddr_in udpserveraddr;
socklen_t addrlen, addrlen2;
int selective,i,fdmax = 0;
char data[SENDBUFFER];
/*UDP creation format*/
new = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
memset(&udpserveraddr, 0, sizeof (udpserveraddr));
udpserveraddr.sin_family = AF_INET;
memcpy(&udpserveraddr.sin_addr.s_addr, hostp->h_addr, hostp->h_length);
udpserveraddr.sin_port = htons(portnumber);
udpserveraddr.sin_addr.s_addr = INADDR_ANY;
if (bind(new, (struct sockaddr *) & udpserveraddr, sizeof (udpserveraddr)) == ERROR) {
}
while (1) {
FD_ZERO(&read_set);
FD_SET(sock, &read_set);
FD_SET(new, &read_set);
FD_SET(fileno(stdin), &read_set);
fdmax = sock+1;
selective = select(FD_SETSIZE, &read_set, NULL, NULL, NULL);
switch (selective) {
default:
if (FD_ISSET(fileno(stdin), &read_set)) {/*user input data on keyboard*/
small_shell();
fflush(stdout);
}
for(i = 0; i<=fdmax;i++) {
if (FD_ISSET(i, &read_set)) { /*We have received something from the server*/
if(i == sock) {
if (connect(i, (struct sockaddr *) & serveraddr, sizeof (serveraddr)) == ERROR) {
check_connection();
}
/*Making two processes where each would be a tcp and udp handling*/
if (insert_tolist(&firstlist,i, machine, clientaddr) == 0) {
printf("inserted to a list\n");
} else {
flagstop = 0;
send_intro(i); /*SEND MONITOR THRESHOLD AND DURATION TO SERVER FIRST*/
//pthread_create(&server_connection,NULL,&process,NULL);
}
}else {
//Receive TCP messages
}
}
}
}
if (FD_ISSET(new, &read_set)) {
//Receive UDP packets
}
break;
}
}
}
