Clients

This section describes the steps taken by the client remote login process. As in the server, the first step is to locate the service definition for a remote login:

sp = getservbyname("login", "tcp");
if (sp == (struct servent *) NULL) {
		fprintf(stderr,"rlogin: tcp/login: unknown service");
		exit(1);
}

Next, the destination host is looked up by a call togetipnodebyname(3SOCKET):

hp = getipnodebyname (AF_INET6, argv[1], AI_DEFAULT, &errnum);
if (hp == (struct hostent *) NULL) {
		fprintf(stderr, "rlogin: %s: unknown host", argv[1]);
		exit(2);
}

The next step is to connect to the server at the requested host and start the remote login protocol. The address buffer is cleared and filled with the Internet address of the foreign host and the port number at which the login server listens:

memset((char *) &server, 0, sizeof server);
bzero (&sin6, sizeof (sin6));
memcpy((char*) &server.sin6_addr,hp->h_addr,hp->h_length);
server.sin6_family = hp->h_addrtype;
server.sin6_port = sp->s_port;

A socket is created, and a connection initiated. connect(3SOCKET) implicitly does a bind(3SOCKET), since s is unbound.

s = socket(hp->h_addrtype, SOCK_STREAM, 0);
if (s < 0) {
		perror("rlogin: socket");
		exit(3);
}
 ...
if (connect(s, (struct sockaddr *) &server, sizeof server) < 0) {
		perror("rlogin: connect");
		exit(4);
}