question about using sockets on sysVr3

[Patrick J. Spinler]

I am attempting to learn to use sockets, however, I am evidently
creating a protocal error of some sort, and have no real idea where to
start looking.  If some kind soul would please tell me why I'm getting
an EINVAL error on my call to bind(), I would be very grateful.  I'm
running sysVr3.1.1 on an at&t 3b2/500 with the WINS tcp/ip and
wollengang socket emulation library installed.

Please email replys, and thanks very much !

-- Pat

--- cut here ---

#include <errno.h>       /* obligatory includes */
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/inet.h>
#include <sys/in.h>
#include <sys/time.h>
#include <netdb.h>
#include <string.h>

#define MAXHOSTNAME	32
#define PORTNUM 	4594

main ()
{
    int    sock_fds, pid, fds, size;
    struct sockaddr_in	sock_add;
    struct sockaddr_in	connect_add;
    struct hostent	*host;
    short  portnum;
    char   hostname[MAXHOSTNAME+1], buffer[80];

    bzero (&sock_add, sizeof (sock_add));

    gethostname (hostname, MAXHOSTNAME);
    host = gethostbyname (hostname);
    if (!host) {
	perror ("getbyhostname");
	exit (1);
    }

    if (host->h_addrtype != AF_INET) {
	perror ("host in wrong address family");
	exit (1);
    }

    /*
     * create the socket !
     */

    sock_fds = socket (AF_INET, SOCK_STREAM, 0);
    if (sock_fds < 0) {
	perror ("socket");
	exit (1);
    }

    pid = fork ();

    if (pid < 0) {
	perror ("fork");
	close (sock_fds);
	exit (1);
    }

    if (pid) {	/* Parent process -- server */

        /* 
         * Name the socket
         */

	bzero (&sock_add, sizeof (sock_add));
	sock_add.sin_family = AF_INET;
	bcopy (host->h_addr, &sock_add.sin_addr, host->h_length);
	sock_add.sin_port = htons ((unsigned short) PORTNUM);	

	if (bind (sock_fds, &sock_add, sizeof (sock_add))) {
	    perror ("bind");
	    close (sock_fds);
	    exit (1);
	}

	size = sizeof (sock_add);
	if (getsockname (sock_fds, &sock_add, &size)) {
	    perror ("getsockname");
	    close (sock_fds);
	    exit (1);
	}
	sprintf (buffer, "Port #%d\n", ntohs (sock_add.sin_port));
	write (1, buffer, strlen (buffer));

	listen (sock_fds, 1);
	size = sizeof (connect_add);
	fds = accept (sock_fds, &connect_add, &size);
	if (fds < 0) {
	    perror ("accept");
	    close (sock_fds);
	    exit (1);
	}

	while ((size = read (fds, buffer, 79))) {
	    write (1, buffer, size);
	}
	close (fds);
	close (sock_fds);
	exit (0);
    }
    else {	/* child */

        /* 
         * Name the socket
         */

	bzero (&sock_add, sizeof (sock_add));
	sock_add.sin_family = AF_INET;
	bcopy (host->h_addr, &sock_add.sin_addr, host->h_length);
	sock_add.sin_port = htons ((unsigned short) PORTNUM);	

        if (connect (sock_fds, &sock_add, sizeof (sock_add)) < 0) {
	    perror ("connect");
	    close (sock_fds);
	    exit (1);
	}
	sprintf (buffer, "connected to port #%d\n", ntohs (sock_add.sin_port));
	write (1, buffer, strlen (buffer));

	strcpy (buffer, "Hi, this is a test !");
	size = strlen (buffer);
	write (sock_fds, buffer, size);
	close (sock_fds);
	exit (0);
    }
}

----
Patrick J. Spinler             		    PSPinler at att1.Mankato.MSUS.EDU
Student Programmer			    PSPinler at vax1.Mankato.MSUS.EDU
Mankato State University		    PSPinler at msus1.MSUS.EDU