usr/src/usr.sbin/timed/timed/acksend.c

/*
 * Copyright (c) 1985 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * University of California, Berkeley and its contributors'' in the
 * documentation or other materials provided with the distribution and in
 * all advertising materials mentioning features or use of this software.
 * 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)acksend.c   2.7 (Berkeley) 6/1/90";
#endif /* not lint */

#include "globals.h"
#include <protocols/timed.h>

#define RECEIVED        0
#define LOST            1
#define SECFORACK       1       /* seconds */
#define USECFORACK      0       /* microseconds */
#define MAXCOUNT        5

struct tsp *answer;

/*
 * Acksend implements reliable datagram transmission by using sequence
 * numbers and retransmission when necessary.
 * `name' is the name of the destination
 * `addr' is the address to send to
 * If `name' is ANYADDR, this routine implements reliable broadcast.
 */

struct tsp *acksend(message, addr, name, ack, net)
struct tsp *message;
struct sockaddr_in *addr;
char *name;
int ack;
struct netinfo *net;
{
        int count;
        int flag;
        extern u_short sequence;
        struct timeval tout;
        struct tsp *readmsg();

        count = 0;

        message->tsp_vers = TSPVERSION;
        message->tsp_seq = sequence;
        if (trace) {
                fprintf(fd, "acksend: ");
                if (name == ANYADDR)
                        fprintf(fd, "broadcast: ");
                else
                        fprintf(fd, "%s: ", name);
                print(message, addr);
        }
        bytenetorder(message);
        do {
                if (sendto(sock, (char *)message, sizeof(struct tsp), 0, addr,
                    sizeof(struct sockaddr_in)) < 0) {
                        syslog(LOG_ERR, "acksend: sendto: %m");
                        exit(1);
                }
                tout.tv_sec = SECFORACK;
                tout.tv_usec = USECFORACK;
                answer  = readmsg(ack, name, &tout, net);
                if (answer != NULL) {
                        if (answer->tsp_seq != sequence) {
                                if (trace)
                                        fprintf(fd, "acksend: seq # %d != %d\n",
                                            answer->tsp_seq, sequence);
                                continue;
                        }
                        flag = RECEIVED;
                } else {
                        flag = LOST;
                        if (++count == MAXCOUNT) {
                                break;
                        }
                }
        } while (flag != RECEIVED);
        sequence++;
        return(answer);
}