/* rfscomm.c - rfscomm */

#include 

/*------------------------------------------------------------------------
 * rfscomm  -  Handle communication with RFS server (send request and
 *              receive a reply, including sequencing and retries)
 *------------------------------------------------------------------------
 */
int32   rfscomm (
         struct rf_msg_hdr *msg,        /* Message to send              */
         int32  mlen,                   /* Message length               */
         struct rf_msg_hdr *reply,      /* Buffer for reply             */
         int32  rlen                    /* Size of reply buffer         */
        )
{
        int32   i;                      /* Counts retries               */
        int32   retval;                 /* Return value                 */
        int32   seq;                    /* Sequence for this exchange   */
        int16   rtype;                  /* Reply type in host byte order*/
        int32   slot;                   /* UDP slot                     */
        char    err[128];               /* Error message buffer         */


        /* For the first time after reboot, register the server port */

        if ( ! Rf_data.rf_registered ) {

            /* Convert the server name to an IP address */

            if (dnslookup(RF_SERVER, &Rf_data.rf_ser_ip) == SYSERR) {
                sprintf(err, "rfs server %s is invalid", RF_SERVER);
                panic("err");
            }

            if ( (slot = udp_register(Rf_data.rf_ser_ip,
                            Rf_data.rf_ser_port,
                            Rf_data.rf_loc_port)) == SYSERR) {
                        return SYSERR;
            }
            Rf_data.rf_udp_slot = slot;
            Rf_data.rf_registered = TRUE;
        }

        /* Assign message next sequence number */

        seq = Rf_data.rf_seq++;
        msg->rf_seq = htonl(seq);

        /* Repeat RF_RETRIES times: send message and receive reply */

        for (i=0; irf_seq) != seq) {
                        continue;
                }

                /* Verify the type in the reply matches the request */

                rtype = ntohs(reply->rf_type);
                if (rtype != ( ntohs(msg->rf_type) | RF_MSG_RESPONSE) ) {
                        continue;
                }
                return retval;          /* Return length to caller */
        }

        /* Retries exhausted without success */

        kprintf("Timeout on exchange with remote file server\n");
        return TIMEOUT;
}