timed.c

早期freebsd实现

/*-
 * 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. 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 copyright[] =
"@(#) Copyright (c) 1985, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)timed.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

#ifdef sgi
#ident "$Revision: 1.25 $"
#endif /* sgi */

#define TSPTYPES
#include "globals.h"
#include <net/if.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <setjmp.h>
#include "pathnames.h"
#include <math.h>
#include <sys/types.h>
#include <sys/times.h>
#ifdef sgi
#include <unistd.h>
#include <sys/syssgi.h>
#include <sys/schedctl.h>
#endif /* sgi */

int trace = 0;
int sock, sock_raw = -1;
int status = 0;
u_short sequence;			/* sequence number */
long delay1;
long delay2;

int nslavenets;				/* nets were I could be a slave */
int nmasternets;			/* nets were I could be a master */
int nignorednets;			/* ignored nets */
int nnets;				/* nets I am connected to */

FILE *fd;				/* trace file FD */

jmp_buf jmpenv;

struct netinfo *nettab = 0;
struct netinfo *slavenet;
int Mflag;
int justquit = 0;
int debug;

static struct nets {
	char	*name;
	long	net;
	struct nets *next;
} *nets = 0;

struct hosttbl hosttbl[NHOSTS+1];	/* known hosts */

static struct goodhost {		/* hosts that we trust */
	char	name[MAXHOSTNAMELEN+1];
	struct goodhost *next;
	char	perm;
} *goodhosts;

static char *goodgroup;			/* net group of trusted hosts */
static void checkignorednets __P((void));
static void pickslavenet __P((struct netinfo *));
static void add_good_host __P((char *, int));

#ifdef sgi
char *timetrim_fn;
char *timetrim_wpat = "long timetrim = %ld;\ndouble tot_adj = %.0f;\ndouble tot_ticks = %.0f;\n/* timed version 2 */\n";
char *timetrim_rpat = "long timetrim = %ld;\ndouble tot_adj = %lf;\ndouble tot_ticks = %lf;";
long timetrim;
double tot_adj, hr_adj;			/* totals in nsec */
double tot_ticks, hr_ticks;

int bufspace = 60*1024;
#endif


/*
 * The timedaemons synchronize the clocks of hosts in a local area network.
 * One daemon runs as master, all the others as slaves. The master
 * performs the task of computing clock differences and sends correction
 * values to the slaves.
 * Slaves start an election to choose a new master when the latter disappears
 * because of a machine crash, network partition, or when killed.
 * A resolution protocol is used to kill all but one of the masters
 * that happen to exist in segments of a partitioned network when the
 * network partition is fixed.
 *
 * Authors: Riccardo Gusella & Stefano Zatti
 *
 * overhauled at Silicon Graphics
 */
int
main(argc, argv)
	int argc;
	char *argv[];
{
	int on;
	int ret;
	int nflag, iflag;
	struct timeval ntime;
	struct servent *srvp;
	char buf[BUFSIZ], *cp, *cplim;
	struct ifconf ifc;
	struct ifreq ifreq, ifreqf, *ifr;
	register struct netinfo *ntp;
	struct netinfo *ntip;
	struct netinfo *savefromnet;
	struct netent *nentp;
	struct nets *nt;
	struct sockaddr_in server;
	u_short port;
	char c;
	extern char *optarg;
	extern int optind, opterr;
#ifdef sgi
	FILE *timetrim_st;
#endif

#define	IN_MSG "timed: -i and -n make no sense together\n"
#ifdef sgi
	struct tms tms;
#define USAGE "timed: [-dtM] [-i net|-n net] [-F host1 host2 ...] [-G netgp] [-P trimfile]\n"
#else
#ifdef HAVENIS
#define USAGE "timed: [-dtM] [-i net|-n net] [-F host1 host2 ...] [-G netgp]\n"
#else
#define USAGE "timed: [-dtM] [-i net|-n net] [-F host1 host2 ...]\n"
#endif /* HAVENIS */
#endif /* sgi */

#ifdef lint
	ntip = NULL;
#endif

	on = 1;
	nflag = OFF;
	iflag = OFF;

#ifdef sgi
	if (0 > syssgi(SGI_GETTIMETRIM, &timetrim)) {
		perror("timed: syssgi(GETTIMETRIM)");
		timetrim = 0;
	}
	tot_ticks = hr_ticks = times(&tms);
#endif /* sgi */

	opterr = 0;
	while ((c = getopt(argc, argv, "Mtdn:i:F:G:P:")) != EOF) {
		switch (c) {
		case 'M':
			Mflag = 1;
			break;

		case 't':
			trace = 1;
			break;

		case 'n':
			if (iflag) {
				fprintf(stderr, IN_MSG);
				exit(1);
			} else {
				nflag = ON;
				addnetname(optarg);
			}
			break;

		case 'i':
			if (nflag) {
				fprintf(stderr, IN_MSG);
				exit(1);
			} else {
				iflag = ON;
				addnetname(optarg);
			}
			break;

		case 'F':
			add_good_host(optarg,1);
			while (optind < argc && argv[optind][0] != '-')
				add_good_host(argv[optind++], 1);
			break;

		case 'd':
			debug = 1;
			break;
		case 'G':
			if (goodgroup != 0) {
				fprintf(stderr,"timed: only one net group\n");
				exit(1);
			}
			goodgroup = optarg;
			break;
#ifdef sgi
		case 'P':
			timetrim_fn = optarg;
			timetrim_st = fopen(timetrim_fn, "r+");
			if (0 == timetrim_st) {
				if (errno != ENOENT) {
					(void)fprintf(stderr,"timed: ");
					perror(timetrim_fn);
					timetrim_fn = 0;
				}
			} else {
				int i;
				long trim;
				double adj, ticks;

				i = fscanf(timetrim_st, timetrim_rpat,
					   &trim, &adj, &ticks);
				if (i < 1
				    || trim > MAX_TRIM
				    || trim < -MAX_TRIM
				    || i == 2
				    || (i == 3
					&& trim != rint(adj*CLK_TCK/ticks))) {
					if (trace && i != EOF)
						(void)fprintf(stderr,
				    "timed: unrecognized contents in %s\n",
							      timetrim_fn);
				} else {
					if (0 > syssgi(SGI_SETTIMETRIM,
						       trim)) {
					 perror("timed: syssgi(SETTIMETRIM)");
					} else {
						timetrim = trim;
					}
					if (i == 3) {
						tot_adj = adj;
						tot_ticks -= ticks;
					}
				}
				(void)fclose(timetrim_st);
			}
			break;
#endif /* sgi */

		default:
			fprintf(stderr, USAGE);
			exit(1);
			break;
		}
	}
	if (optind < argc) {
		fprintf(stderr, USAGE);
		exit(1);
	}

	/* If we care about which machine is the master, then we must
	 *	be willing to be a master
	 */
	if (0 != goodgroup || 0 != goodhosts)
		Mflag = 1;

	if (gethostname(hostname, sizeof(hostname) - 1) < 0) {
		perror("gethostname");
		exit(1);
	}
	self.l_bak = &self;
	self.l_fwd = &self;
	self.h_bak = &self;
	self.h_fwd = &self;
	self.head = 1;
	self.good = 1;

	if (goodhosts != 0)		/* trust ourself */
		add_good_host(hostname,1);

	srvp = getservbyname("timed", "udp");
	if (srvp == 0) {
		fprintf(stderr, "unknown service 'timed/udp'\n");
		exit(1);
	}
	port = srvp->s_port;
	server.sin_port = srvp->s_port;
	server.sin_family = AF_INET;
	sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock < 0) {
		perror("socket");
		exit(1);
	}
	if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&on,
							sizeof(on)) < 0) {
		perror("setsockopt");
		exit(1);
	}
	if (bind(sock, (struct sockaddr*)&server, sizeof(server))) {
		if (errno == EADDRINUSE)
			fprintf(stderr,"timed: time daemon already running\n");
		else
			perror("bind");
		exit(1);
	}
#ifdef sgi
	/*
	 * handle many slaves with our buffer
	 */
	if (0 > setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (char*)&bufspace,
			 sizeof(bufspace))) {
		perror("setsockopt");
		exit(1);
	}
#endif /* sgi */

	/* choose a unique seed for random number generation */
	(void)gettimeofday(&ntime, 0);
	srandom(ntime.tv_sec + ntime.tv_usec);

	sequence = random();     /* initial seq number */

#ifndef sgi
	/* rounds kernel variable time to multiple of 5 ms. */
	ntime.tv_sec = 0;
	ntime.tv_usec = -((ntime.tv_usec/1000) % 5) * 1000;
	(void)adjtime(&ntime, (struct timeval *)0);
#endif /* sgi */

	for (nt = nets; nt; nt = nt->next) {
		nentp = getnetbyname(nt->name);
		if (nentp == 0) {
			nt->net = inet_network(nt->name);
			if (nt->net != INADDR_NONE)
				nentp = getnetbyaddr(nt->net, AF_INET);
		}
		if (nentp != 0) {
			nt->net = nentp->n_net;
		} else if (nt->net == INADDR_NONE) {
			fprintf(stderr, "timed: unknown net %s\n", nt->name);
			exit(1);
		} else if (nt->net == INADDR_ANY) {
			fprintf(stderr, "timed: bad net %s\n", nt->name);
			exit(1);
		} else {
			fprintf(stderr,
				"timed: warning: %s unknown in /etc/networks\n",
				nt->name);
		}

		if (0 == (nt->net & 0xff000000))
		    nt->net <<= 8;
		if (0 == (nt->net & 0xff000000))
		    nt->net <<= 8;
		if (0 == (nt->net & 0xff000000))
		    nt->net <<= 8;
	}
	ifc.ifc_len = sizeof(buf);
	ifc.ifc_buf = buf;
	if (ioctl(sock, SIOCGIFCONF, (char *)&ifc) < 0) {
		perror("timed: get interface configuration");
		exit(1);
	}
	ntp = NULL;
#ifdef sgi
#define size(p)	(sizeof(*ifr) - sizeof(ifr->ifr_name))  /* XXX hack. kludge */
#else
#define size(p)	max((p).sa_len, sizeof(p))
#endif
	cplim = buf + ifc.ifc_len; /*skip over if's with big ifr_addr's */
	for (cp = buf; cp < cplim;
			cp += sizeof (ifr->ifr_name) + size(ifr->ifr_addr)) {
		ifr = (struct ifreq *)cp;
		if (ifr->ifr_addr.sa_family != AF_INET)
			continue;
		if (!ntp)
			ntp = (struct netinfo*)malloc(sizeof(struct netinfo));
		bzero(ntp,sizeof(*ntp));
		ntp->my_addr=((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
		ntp->status = NOMASTER;
		ifreq = *ifr;
		ifreqf = *ifr;

		if (ioctl(sock, SIOCGIFFLAGS, (char *)&ifreqf) < 0) {
			perror("get interface flags");
			continue;
		}
		if ((ifreqf.ifr_flags & IFF_UP) == 0)
			continue;
		if ((ifreqf.ifr_flags & IFF_BROADCAST) == 0 &&
		    (ifreqf.ifr_flags & IFF_POINTOPOINT) == 0) {
			continue;
		}


		if (ioctl(sock, SIOCGIFNETMASK, (char *)&ifreq) < 0) {
			perror("get netmask");
			continue;
		}
		ntp->mask = ((struct sockaddr_in *)
			&ifreq.ifr_addr)->sin_addr.s_addr;

		if (ifreqf.ifr_flags & IFF_BROADCAST) {
			if (ioctl(sock, SIOCGIFBRDADDR, (char *)&ifreq) < 0) {
				perror("get broadaddr");
				continue;
			}
			ntp->dest_addr = *(struct sockaddr_in *)&ifreq.ifr_broadaddr;
			/* What if the broadcast address is all ones?
			 * So we cannot just mask ntp->dest_addr.  */
			ntp->net = ntp->my_addr;
			ntp->net.s_addr &= ntp->mask;
		} else {
			if (ioctl(sock, SIOCGIFDSTADDR,
						(char *)&ifreq) < 0) {
				perror("get destaddr");
				continue;
			}
			ntp->dest_addr = *(struct sockaddr_in *)&ifreq.ifr_dstaddr;
			ntp->net = ntp->dest_addr.sin_addr;
		}

		ntp->dest_addr.sin_port = port;

		for (nt = nets; nt; nt = nt->next) {
			if (ntp->net.s_addr == nt->net)
				break;
		}
		if (nflag && !nt || iflag && nt)
			continue;

		ntp->next = NULL;
		if (nettab == NULL) {
			nettab = ntp;
		} else {
			ntip->next = ntp;
		}
		ntip = ntp;
		ntp = NULL;
	}
	if (ntp)
		(void) free((char *)ntp);
	if (nettab == NULL) {
		fprintf(stderr, "timed: no network usable\n");
		exit(1);
	}


#ifdef sgi
	(void)schedctl(RENICE,0,10);	   /* run fast to get good time */

	/* ticks to delay before responding to a broadcast */
	delay1 = casual(0, CLK_TCK/10);
#else

	/* microseconds to delay before responding to a broadcast */
	delay1 = casual(1, 100*1000);
#endif /* sgi */

	/* election timer delay in secs. */
	delay2 = casual(MINTOUT, MAXTOUT);