usr/src/bin/date/netdate.c

/*-
 * Copyright (c) 1990 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static char sccsid[] = "@(#)netdate.c   5.2 (Berkeley) 2/25/91";
#endif /* not lint */

#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <netinet/in.h>
#include <netdb.h>
#define TSPTYPES
#include <protocols/timed.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

#define WAITACK         2       /* seconds */
#define WAITDATEACK     5       /* seconds */

extern int retval;

/*
 * Set the date in the machines controlled by timedaemons by communicating the
 * new date to the local timedaemon.  If the timedaemon is in the master state,
 * it performs the correction on all slaves.  If it is in the slave state, it
 * notifies the master that a correction is needed.
 * Returns 0 on success.  Returns > 0 on failure, setting retval to 2;
 */
netsettime(tval)
        time_t tval;
{
        struct timeval tout;
        struct servent *sp;
        struct tsp msg;
        struct sockaddr_in sin, dest, from;
        fd_set ready;
        long waittime;
        int s, length, port, timed_ack, found, err;
        char hostname[MAXHOSTNAMELEN];

        if ((sp = getservbyname("timed", "udp")) == NULL) {
                (void)fprintf(stderr, "date: udp/timed: unknown service.n");
                return (retval = 2);
        }

        dest.sin_port = sp->s_port;
        dest.sin_family = AF_INET;
        dest.sin_addr.s_addr = htonl((u_long)INADDR_ANY);
        s = socket(AF_INET, SOCK_DGRAM, 0);
        if (s < 0) {
                if (errno != EPROTONOSUPPORT)
                        perror("date: timed");
                return(retval = 2);
        }

        bzero((char *)&sin, sizeof(sin));
        sin.sin_family = AF_INET;
        for (port = IPPORT_RESERVED - 1; port > IPPORT_RESERVED / 2; port--) {
                sin.sin_port = htons((u_short)port);
                if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
                        break;
                if (errno == EADDRINUSE)
                        continue;
                if (errno != EADDRNOTAVAIL)
                        perror("date: bind");
                goto bad;
        }
        if (port == IPPORT_RESERVED / 2) {
                (void)fprintf(stderr, "date: all ports in use.\n");
                goto bad;
        }
        msg.tsp_type = TSP_SETDATE;
        msg.tsp_vers = TSPVERSION;
        if (gethostname(hostname, sizeof(hostname))) {
                perror("date: gethostname");
                goto bad;
        }
        (void)strncpy(msg.tsp_name, hostname, sizeof(hostname));
        msg.tsp_seq = htons((u_short)0);
        msg.tsp_time.tv_sec = htonl((u_long)tval);
        msg.tsp_time.tv_usec = htonl((u_long)0);
        length = sizeof(struct sockaddr_in);
        if (connect(s, (struct sockaddr *)&dest, length) < 0) {
                perror("date: connect");
                goto bad;
        }
        if (send(s, (char *)&msg, sizeof(struct tsp), 0) < 0) {
                if (errno != ECONNREFUSED)
                        perror("date: send");
                goto bad;
        }

        timed_ack = -1;
        waittime = WAITACK;
loop:
        tout.tv_sec = waittime;
        tout.tv_usec = 0;

        FD_ZERO(&ready);
        FD_SET(s, &ready);
        found = select(FD_SETSIZE, &ready, (fd_set *)0, (fd_set *)0, &tout);

        length = sizeof(err);
        if (!getsockopt(s, SOL_SOCKET, SO_ERROR, (char *)&err, &length)
            && err) {
                if (err != ECONNREFUSED)
                        perror("date: send (delayed error)");
                goto bad;
        }

        if (found > 0 && FD_ISSET(s, &ready)) {
                length = sizeof(struct sockaddr_in);
                if (recvfrom(s, &msg, sizeof(struct tsp), 0,
                    (struct sockaddr *)&from, &length) < 0) {
                        if (errno != ECONNREFUSED)
                                perror("date: recvfrom");
                        goto bad;
                }
                msg.tsp_seq = ntohs(msg.tsp_seq);
                msg.tsp_time.tv_sec = ntohl(msg.tsp_time.tv_sec);
                msg.tsp_time.tv_usec = ntohl(msg.tsp_time.tv_usec);
                switch (msg.tsp_type) {
                case TSP_ACK:
                        timed_ack = TSP_ACK;
                        waittime = WAITDATEACK;
                        goto loop;
                case TSP_DATEACK:
                        (void)close(s);
                        return (0);
                default:
                        (void)fprintf(stderr,
                            "date: wrong ack received from timed: %s.\n",
                            tsptype[msg.tsp_type]);
                        timed_ack = -1;
                        break;
                }
        }
        if (timed_ack == -1)
                (void)fprintf(stderr,
                    "date: can't reach time daemon, time set locally.\n");

bad:
        (void)close(s);
        return(retval = 2);
}