/*      $NetBSD: acksend.c,v 1.11 2007/01/26 16:12:41 christos Exp $    */

/*-
 * Copyright (c) 1985, 1993 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)acksend.c   8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: acksend.c,v 1.11 2007/01/26 16:12:41 christos Exp $");
#endif
#endif /* not lint */

#include "globals.h"


struct tsp *answer;

extern u_short sequence;

void
xmit(int type, u_short seq, struct sockaddr_in *addr)
{
        static struct tsp msg;

        msg.tsp_type = type;
        msg.tsp_seq = seq;
        msg.tsp_vers = TSPVERSION;

        set_tsp_name(&msg, hostname);
        bytenetorder(&msg);
        (void)sendtsp(sock, &msg, addr);
}

int
sendtsp(int s, struct tsp *msg, struct sockaddr_in *addr)
{
        int error;

        error = sendto(s, msg, sizeof(*msg), 0,
            (struct sockaddr *)(void *)addr, sizeof(*addr));
        if (error == -1)
                trace_sendto_err(addr->sin_addr);
        return error;
}


/*
 * Acksend implements reliable datagram transmission by using sequence
 * numbers and retransmission when necessary.
 * If `name' is ANYADDR, this routine implements reliable broadcast.
 *
 * Because this function calls readmsg(), none of its args may be in
 *      a message provided by readmsg().
 */
struct tsp *
acksend(struct tsp *message,            /* this message */
        struct sockaddr_in *addr, char *name,   /* to here */
        int ack,                        /* look for this ack */
        struct netinfo *net,            /* receive from this network */
        int bad)                        /* 1=losing patience */
{
        struct timeval twait;
        int count;
        long msec;

        message->tsp_vers = TSPVERSION;
        message->tsp_seq = sequence;
        if (trace) {
                fprintf(fd, "acksend: to %s: ",
                        (name == ANYADDR ? "broadcast" : name));
                print(message, addr);
        }
        bytenetorder(message);

        msec = 200;
        count = bad ? 1 : 5;    /* 5 packets in 6.4 seconds */
        answer = 0;
        do {
                if (!answer) {
                        /* do not go crazy transmitting just because the
                         * other guy cannot keep our sequence numbers
                         * straight.
                         */
                        if (sendtsp(sock, message, addr) == -1)
                                break;
                }

                mstotvround(&twait, msec);
                answer  = readmsg(ack, name, &twait, net);
                if (answer != 0) {
                        if (answer->tsp_seq != sequence) {
                                if (trace)
                                        fprintf(fd,"acksend: seq # %u!=%u\n",
                                                answer->tsp_seq, sequence);
                                continue;
                        }
                        break;
                }

                msec *= 2;
        } while (--count > 0);
        sequence++;

        return(answer);
}