/* rdscomm.c - rdscomm */

#include 

/*------------------------------------------------------------------------
 * rdscomm  -  send a request message to the remote disk server and
 *               a reply, handling sequence numbers and retries
 *------------------------------------------------------------------------
 */
status  rdscomm (
          struct rd_msg_hdr *msg,       /* Message to send              */
          int32             mlen,       /* Message length               */
          struct rd_msg_hdr *reply,     /* Buffer for reply             */
          int32             rlen,       /* Size of reply buffer         */
          struct rdscblk    *rdptr      /* Ptr to device control block  */
        )
{
        intmask         mask;           /* Saved interrupt mask         */
        int32           i;              /* Counts retries               */
        int32           retval;         /* Return value                 */
        int32           seq;            /* Sequence for this exchange   */
        uint32          localip;        /* Local IP address             */
        int16           rtype;          /* Reply type in host byte order*/
        bool8           xmit;           /* Should we transmit again?    */
        int32           slot;           /* UDP slot                     */

        /* Disable interrupts while testing status */

        mask = disable();

        /* Register the server port, if not registered */

        if ( ! rdptr->rd_registered ) {
                slot = udp_register(rdptr->rd_ser_ip, rdptr->rd_ser_port,
                                        rdptr->rd_loc_port);
                if(slot == SYSERR) {
                        restore(mask);
                        return SYSERR;
                }
                rdptr->rd_udpslot = slot;
                rdptr->rd_registered = TRUE;
        }

        /* Get the local IP address */

        if ( NetData.ipvalid == FALSE ) {
                localip = getlocalip();
                if((int32)localip == SYSERR) {
                        restore(mask);
                        return SYSERR;
                }
        }
        restore(mask);

        /* Retrieve the saved UDP slot number  */

        slot = rdptr->rd_udpslot;

        /* Assign message next sequence number */

        seq = rdptr->rd_seq++;
        msg->rd_seq = htonl(seq);

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

        xmit = TRUE;
        for (i=0; ird_seq) < seq) {
                xmit = FALSE;
            } else if (ntohl(reply->rd_seq) != seq) {
                        continue;
            }

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

            rtype = ntohs(reply->rd_type);
            if (rtype != ( ntohs(msg->rd_type) | RD_MSG_RESPONSE) ) {
                continue;
            }

            /* Verify that the reply status is valid */

            if (ntohs(reply->rd_status) != 0) {
                return SYSERR;
            }

            return OK;
        }

        /* Retries exhausted without success */

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