Ejemplo n.º 1
0
/*
 * react to a TSP_QUIT:
 */
void
doquit(struct tsp *msg)
{
	if (fromnet->status == MASTER) {
		if (!good_host_name(msg->tsp_name)) {
			if (fromnet->quit_count <= 0) {
				syslog(LOG_NOTICE,"untrusted %s told us QUIT",
				       msg->tsp_name);
				suppress(&from, msg->tsp_name, fromnet);
				fromnet->quit_count = 1;
				return;
			}
			syslog(LOG_NOTICE, "untrusted %s told us QUIT twice",
			       msg->tsp_name);
			fromnet->quit_count = 2;
			fromnet->status = NOMASTER;
		} else {
			fromnet->status = SLAVE;
		}
		rmnetmachs(fromnet);
		longjmp(jmpenv, 2);		/* give up and be a slave */

	} else {
		if (!good_host_name(msg->tsp_name)) {
			syslog(LOG_NOTICE, "untrusted %s told us QUIT",
			       msg->tsp_name);
			fromnet->quit_count = 2;
		}
	}
}
Ejemplo n.º 2
0
int
slave()
{
	int tries;
	long electiontime, refusetime, looktime, looptime, adjtime;
	u_short seq;
	long fastelection;
#define FASTTOUT 3
	struct in_addr cadr;
	struct timeval otime;
	struct sockaddr_in taddr;
	char tname[MAXHOSTNAMELEN];
	struct tsp *msg, to;
	struct timeval ntime, wait, tmptv;
	time_t tsp_time_sec;
	struct tsp *answer;
	int timeout();
	char olddate[32];
	char newdate[32];
	struct netinfo *ntp;
	struct hosttbl *htp;
	struct utmpx utx;


	old_slavenet = 0;
	seq = 0;
	refusetime = 0;
	adjtime = 0;

	(void)gettimeofday(&ntime, NULL);
	electiontime = ntime.tv_sec + delay2;
	fastelection = ntime.tv_sec + FASTTOUT;
	if (justquit)
		looktime = electiontime;
	else
		looktime = fastelection;
	looptime = fastelection;

	if (slavenet)
		xmit(TSP_SLAVEUP, 0, &slavenet->dest_addr);
	if (status & MASTER) {
		for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
			if (ntp->status == MASTER)
				masterup(ntp);
		}
	}

loop:
	get_goodgroup(0);
	(void)gettimeofday(&ntime, NULL);
	if (ntime.tv_sec > electiontime) {
		if (trace)
			fprintf(fd, "election timer expired\n");
		longjmp(jmpenv, 1);
	}

	if (ntime.tv_sec >= looktime) {
		if (trace)
			fprintf(fd, "Looking for nets to master\n");

		if (Mflag && nignorednets > 0) {
			for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
				if (ntp->status == IGNORE
				    || ntp->status == NOMASTER) {
					lookformaster(ntp);
					if (ntp->status == MASTER) {
						masterup(ntp);
					} else if (ntp->status == MASTER) {
						ntp->status = NOMASTER;
					}
				}
				if (ntp->status == MASTER
				    && --ntp->quit_count < 0)
					ntp->quit_count = 0;
			}
			makeslave(slavenet);	/* prune extras */
			setstatus();
		}
		(void)gettimeofday(&ntime, NULL);
		looktime = ntime.tv_sec + delay2;
	}
	if (ntime.tv_sec >= looptime) {
		if (trace)
			fprintf(fd, "Looking for loops\n");
		for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
		    if (ntp->status == MASTER) {
			to.tsp_type = TSP_LOOP;
			to.tsp_vers = TSPVERSION;
			to.tsp_seq = sequence++;
			to.tsp_hopcnt = MAX_HOPCNT;
			(void)strcpy(to.tsp_name, hostname);
			bytenetorder(&to);
			if (sendto(sock, (char *)&to, sizeof(struct tsp), 0,
				   (struct sockaddr*)&ntp->dest_addr,
				   sizeof(ntp->dest_addr)) < 0) {
				trace_sendto_err(ntp->dest_addr.sin_addr);
			}
		    }
		}
		(void)gettimeofday(&ntime, NULL);
		looptime = ntime.tv_sec + delay2;
	}

	wait.tv_sec = min(electiontime,min(looktime,looptime)) - ntime.tv_sec;
	if (wait.tv_sec < 0)
		wait.tv_sec = 0;
	wait.tv_sec += FASTTOUT;
	wait.tv_usec = 0;
	msg = readmsg(TSP_ANY, ANYADDR, &wait, 0);

	if (msg != NULL) {
		/*
		 * filter stuff not for us
		 */
		switch (msg->tsp_type) {
		case TSP_SETDATE:
		case TSP_TRACEOFF:
		case TSP_TRACEON:
			/*
			 * XXX check to see they are from ourself
			 */
			break;

		case TSP_TEST:
		case TSP_MSITE:
			break;

		case TSP_MASTERUP:
			if (!fromnet) {
				if (trace) {
					fprintf(fd, "slave ignored: ");
					print(msg, &from);
				}
				goto loop;
			}
			break;

		default:
			if (!fromnet
			    || fromnet->status == IGNORE
			    || fromnet->status == NOMASTER) {
				if (trace) {
					fprintf(fd, "slave ignored: ");
					print(msg, &from);
				}
				goto loop;
			}
			break;
		}


		/*
		 * now process the message
		 */
		switch (msg->tsp_type) {

		case TSP_ADJTIME:
			if (fromnet != slavenet)
				break;
			if (!good_host_name(msg->tsp_name)) {
				syslog(LOG_NOTICE,
				   "attempted time adjustment by %s",
				       msg->tsp_name);
				suppress(&from, msg->tsp_name, fromnet);
				break;
			}
			/*
			 * Speed up loop detection in case we have a loop.
			 * Otherwise the clocks can race until the loop
			 * is found.
			 */
			(void)gettimeofday(&otime, NULL);
			if (adjtime < otime.tv_sec)
				looptime -= (looptime-otime.tv_sec)/2 + 1;

			setmaster(msg);
			if (seq != msg->tsp_seq) {
				seq = msg->tsp_seq;
				synch(tvtomsround(msg->tsp_time));
			}
			(void)gettimeofday(&ntime, NULL);
			electiontime = ntime.tv_sec + delay2;
			fastelection = ntime.tv_sec + FASTTOUT;
			adjtime = ntime.tv_sec + SAMPLEINTVL*2;
			break;

		case TSP_SETTIME:
			if (fromnet != slavenet)
				break;
			if (seq == msg->tsp_seq)
				break;
			seq = msg->tsp_seq;

			/* adjust time for residence on the queue */
			(void)gettimeofday(&otime, NULL);
			adj_msg_time(msg,&otime);
			/*
			 * the following line is necessary due to syslog
			 * calling ctime() which clobbers the static buffer
			 */
			(void)strcpy(olddate, date());
			tsp_time_sec = msg->tsp_time.tv_sec;
			(void)strcpy(newdate, ctime(&tsp_time_sec));

			if (!good_host_name(msg->tsp_name)) {
				syslog(LOG_NOTICE,
			    "attempted time setting by untrusted %s to %s",
				       msg->tsp_name, newdate);
				suppress(&from, msg->tsp_name, fromnet);
				break;
			}

			setmaster(msg);
 			tmptv.tv_sec = msg->tsp_time.tv_sec;
 			tmptv.tv_usec = msg->tsp_time.tv_usec;
			timevalsub(&ntime, &tmptv, &otime);
			if (ntime.tv_sec < MAXADJ && ntime.tv_sec > -MAXADJ) {
				/*
				 * do not change the clock if we can adjust it
				 */
				synch(tvtomsround(ntime));
			} else {
				utx.ut_type = OLD_TIME;
				gettimeofday(&utx.ut_tv, NULL);
				pututxline(&utx);
				(void)settimeofday(&tmptv, 0);
				utx.ut_type = NEW_TIME;
				gettimeofday(&utx.ut_tv, NULL);
				pututxline(&utx);
				syslog(LOG_NOTICE,
				       "date changed by %s from %s",
					msg->tsp_name, olddate);
				if (status & MASTER)
					spreadtime();
			}
			(void)gettimeofday(&ntime, NULL);
			electiontime = ntime.tv_sec + delay2;
			fastelection = ntime.tv_sec + FASTTOUT;

/* This patches a bad protocol bug.  Imagine a system with several networks,
 * where there are a pair of redundant gateways between a pair of networks,
 * each running timed.  Assume that we start with a third machine mastering
 * one of the networks, and one of the gateways mastering the other.
 * Imagine that the third machine goes away and the non-master gateway
 * decides to replace it.  If things are timed just 'right,' we will have
 * each gateway mastering one network for a little while.  If a SETTIME
 * message gets into the network at that time, perhaps from the newly
 * masterful gateway as it was taking control, the SETTIME will loop
 * forever.  Each time a gateway receives it on its slave side, it will
 * call spreadtime to forward it on its mastered network.  We are now in
 * a permanent loop, since the SETTIME msgs will keep any clock
 * in the network from advancing.  Normally, the 'LOOP' stuff will detect
 * and correct the situation.  However, with the clocks stopped, the
 * 'looptime' timer cannot expire.  While they are in this state, the
 * masters will try to saturate the network with SETTIME packets.
 */
			looptime = ntime.tv_sec + (looptime-otime.tv_sec)/2-1;
			break;

		case TSP_MASTERUP:
			if (slavenet && fromnet != slavenet)
				break;
			if (!good_host_name(msg->tsp_name)) {
				suppress(&from, msg->tsp_name, fromnet);
				if (electiontime > fastelection)
					electiontime = fastelection;
				break;
			}
			makeslave(fromnet);
			setmaster(msg);
			setstatus();
			answerdelay();
			xmit(TSP_SLAVEUP, 0, &from);
			(void)gettimeofday(&ntime, NULL);
			electiontime = ntime.tv_sec + delay2;
			fastelection = ntime.tv_sec + FASTTOUT;
			refusetime = 0;
			break;

		case TSP_MASTERREQ:
			if (fromnet->status != SLAVE)
				break;
			(void)gettimeofday(&ntime, NULL);
			electiontime = ntime.tv_sec + delay2;
			break;

		case TSP_SETDATE:
			tsp_time_sec = msg->tsp_time.tv_sec;
			(void)strcpy(newdate, ctime(&tsp_time_sec));
			schgdate(msg, newdate);
			break;

		case TSP_SETDATEREQ:
			if (fromnet->status != MASTER)
				break;
			tsp_time_sec = msg->tsp_time.tv_sec;
			(void)strcpy(newdate, ctime(&tsp_time_sec));
			htp = findhost(msg->tsp_name);
			if (0 == htp) {
				syslog(LOG_WARNING,
				       "DATEREQ from uncontrolled machine");
				break;
			}
			if (!htp->good) {
				syslog(LOG_WARNING,
				"attempted date change by untrusted %s to %s",
				       htp->name, newdate);
				spreadtime();
				break;
			}
			schgdate(msg, newdate);
			break;

		case TSP_TRACEON:
			traceon();
			break;

		case TSP_TRACEOFF:
			traceoff("Tracing ended at %s\n");
			break;

		case TSP_SLAVEUP:
			newslave(msg);
			break;

		case TSP_ELECTION:
			if (fromnet->status == SLAVE) {
				(void)gettimeofday(&ntime, NULL);
				electiontime = ntime.tv_sec + delay2;
				fastelection = ntime.tv_sec + FASTTOUT;
				seq = 0;
				if (!good_host_name(msg->tsp_name)) {
					syslog(LOG_NOTICE,
					       "suppress election of %s",
					       msg->tsp_name);
					to.tsp_type = TSP_QUIT;
					electiontime = fastelection;
				} else if (cadr.s_addr != from.sin_addr.s_addr
					   && ntime.tv_sec < refusetime) {
/* if the candidate has to repeat itself, the old code would refuse it
 * the second time.  That would prevent elections.
 */
					to.tsp_type = TSP_REFUSE;
				} else {
					cadr.s_addr = from.sin_addr.s_addr;
					to.tsp_type = TSP_ACCEPT;
					refusetime = ntime.tv_sec + 30;
				}
				taddr = from;
				(void)strcpy(tname, msg->tsp_name);
				(void)strcpy(to.tsp_name, hostname);
				answerdelay();
				if (!acksend(&to, &taddr, tname,
					     TSP_ACK, 0, 0))
					syslog(LOG_WARNING,
					     "no answer from candidate %s\n",
					       tname);

			} else {	/* fromnet->status == MASTER */
				htp = addmach(msg->tsp_name, &from,fromnet);
				to.tsp_type = TSP_QUIT;
				(void)strcpy(to.tsp_name, hostname);
				if (!acksend(&to, &htp->addr, htp->name,
					     TSP_ACK, 0, htp->noanswer)) {
					syslog(LOG_ERR,
					  "no reply from %s to ELECTION-QUIT",
					       htp->name);
					(void)remmach(htp);
				}
			}
			break;

		case TSP_CONFLICT:
			if (fromnet->status != MASTER)
				break;
			/*
			 * After a network partition, there can be
			 * more than one master: the first slave to
			 * come up will notify here the situation.
			 */
			(void)strcpy(to.tsp_name, hostname);

			/* The other master often gets into the same state,
			 * with boring results.
			 */
			ntp = fromnet;	/* (acksend() can leave fromnet=0 */
			for (tries = 0; tries < 3; tries++) {
				to.tsp_type = TSP_RESOLVE;
				answer = acksend(&to, &ntp->dest_addr,
						 ANYADDR, TSP_MASTERACK,
						 ntp, 0);
				if (answer == NULL)
					break;
				htp = addmach(answer->tsp_name,&from,ntp);
				to.tsp_type = TSP_QUIT;
				answer = acksend(&to, &htp->addr, htp->name,
						 TSP_ACK, 0, htp->noanswer);
				if (!answer) {
					syslog(LOG_WARNING,
				  "conflict error: no reply from %s to QUIT",
						htp->name);
					(void)remmach(htp);
				}
			}
			masterup(ntp);
			break;

		case TSP_MSITE:
			if (!slavenet)
				break;
			taddr = from;
			to.tsp_type = TSP_MSITEREQ;
			to.tsp_vers = TSPVERSION;
			to.tsp_seq = 0;
			(void)strcpy(to.tsp_name, hostname);
			answer = acksend(&to, &slavenet->dest_addr,
					 ANYADDR, TSP_ACK,
					 slavenet, 0);
			if (answer != NULL
			    && good_host_name(answer->tsp_name)) {
				setmaster(answer);
				to.tsp_type = TSP_ACK;
				(void)strcpy(to.tsp_name, answer->tsp_name);
				bytenetorder(&to);
				if (sendto(sock, (char *)&to,
					   sizeof(struct tsp), 0,
					   (struct sockaddr*)&taddr,
					   sizeof(taddr)) < 0) {
					trace_sendto_err(taddr.sin_addr);
				}
			}
			break;

		case TSP_MSITEREQ:
			break;

		case TSP_ACCEPT:
		case TSP_REFUSE:
		case TSP_RESOLVE:
			break;

		case TSP_QUIT:
			doquit(msg);		/* become a slave */
			break;

		case TSP_TEST:
			electiontime = 0;
			break;

		case TSP_LOOP:
			/* looking for loops of masters */
			if (!(status & MASTER))
				break;
			if (fromnet->status == SLAVE) {
			    if (!strcmp(msg->tsp_name, hostname)) {
				/*
				 * Someone forwarded our message back to
				 * us.  There must be a loop.  Tell the
				 * master of this network to quit.
				 *
				 * The other master often gets into
				 * the same state, with boring results.
				 */
				ntp = fromnet;
				for (tries = 0; tries < 3; tries++) {
				    to.tsp_type = TSP_RESOLVE;
				    answer = acksend(&to, &ntp->dest_addr,
						     ANYADDR, TSP_MASTERACK,
						     ntp,0);
				    if (answer == NULL)
					break;
				    taddr = from;
				    (void)strcpy(tname, answer->tsp_name);
				    to.tsp_type = TSP_QUIT;
				    (void)strcpy(to.tsp_name, hostname);
				    if (!acksend(&to, &taddr, tname,
						 TSP_ACK, 0, 1)) {
					syslog(LOG_ERR,
					"no reply from %s to slave LOOP-QUIT",
						 tname);
				    } else {
					electiontime = 0;
				    }
				}
				(void)gettimeofday(&ntime, NULL);
				looptime = ntime.tv_sec + FASTTOUT;
			    } else {
				if (msg->tsp_hopcnt-- < 1)
				    break;
				bytenetorder(msg);
				for (ntp = nettab; ntp != 0; ntp = ntp->next) {
				    if (ntp->status == MASTER
					&& 0 > sendto(sock, (char *)msg,
						      sizeof(struct tsp), 0,
					      (struct sockaddr*)&ntp->dest_addr,
						      sizeof(ntp->dest_addr)))
				    trace_sendto_err(ntp->dest_addr.sin_addr);
				}
			    }
			} else {	/* fromnet->status == MASTER */
			    /*
			     * We should not have received this from a net
			     * we are master on.  There must be two masters,
			     * unless the packet was really from us.
			     */
			    if (from.sin_addr.s_addr
				== fromnet->my_addr.s_addr) {
				if (trace)
				    fprintf(fd,"discarding forwarded LOOP\n");
				break;
			    }

			    /*
			     * The other master often gets into the same
			     * state, with boring results.
			     */
			    ntp = fromnet;
			    for (tries = 0; tries < 3; tries++) {
				to.tsp_type = TSP_RESOLVE;
				answer = acksend(&to, &ntp->dest_addr,
						 ANYADDR, TSP_MASTERACK,
						ntp,0);
				if (!answer)
					break;
				htp = addmach(answer->tsp_name,
					      &from,ntp);
				to.tsp_type = TSP_QUIT;
				(void)strcpy(to.tsp_name, hostname);
				if (!acksend(&to,&htp->addr,htp->name,
					     TSP_ACK, 0, htp->noanswer)) {
					syslog(LOG_ERR,
				    "no reply from %s to master LOOP-QUIT",
					       htp->name);
					(void)remmach(htp);
				}
			    }
			    (void)gettimeofday(&ntime, NULL);
			    looptime = ntime.tv_sec + FASTTOUT;
			}
			break;
		default:
			if (trace) {
				fprintf(fd, "garbage message: ");
				print(msg, &from);
			}
			break;
		}
	}
	goto loop;
}
Ejemplo n.º 3
0
/*
 * The main function of `master' is to periodically compute the differences
 * (deltas) between its clock and the clocks of the slaves, to compute the
 * network average delta, and to send to the slaves the differences between
 * their individual deltas and the network delta.
 * While waiting, it receives messages from the slaves (i.e. requests for
 * master's name, remote requests to set the network time, ...), and
 * takes the appropriate action.
 */
int
master()
{
	struct hosttbl *htp;
	long pollingtime;
#define POLLRATE 4
	int polls;
	struct timeval wait, ntime;
	time_t tsp_time_sec;
	struct tsp *msg, *answer, to;
	char newdate[32];
	struct sockaddr_in taddr;
	char tname[MAXHOSTNAMELEN];
	struct netinfo *ntp;
	int i;

	syslog(LOG_NOTICE, "This machine is master");
	if (trace)
		fprintf(fd, "This machine is master\n");
	for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
		if (ntp->status == MASTER)
			masterup(ntp);
	}
	(void)gettimeofday(&ntime, 0);
	pollingtime = ntime.tv_sec+3;
	if (justquit)
		polls = 0;
	else
		polls = POLLRATE-1;

/* Process all outstanding messages before spending the long time necessary
 *	to update all timers.
 */
loop:
	(void)gettimeofday(&ntime, 0);
	wait.tv_sec = pollingtime - ntime.tv_sec;
	if (wait.tv_sec < 0)
		wait.tv_sec = 0;
	wait.tv_usec = 0;
	msg = readmsg(TSP_ANY, ANYADDR, &wait, 0);
	if (!msg) {
		(void)gettimeofday(&ntime, 0);
		if (ntime.tv_sec >= pollingtime) {
			pollingtime = ntime.tv_sec + SAMPLEINTVL;
			get_goodgroup(0);

/* If a bogus master told us to quit, we can have decided to ignore a
 * network.  Therefore, periodically try to take over everything.
 */
			polls = (polls + 1) % POLLRATE;
			if (0 == polls && nignorednets > 0) {
				trace_msg("Looking for nets to re-master\n");
				for (ntp = nettab; ntp; ntp = ntp->next) {
					if (ntp->status == IGNORE
					    || ntp->status == NOMASTER) {
						lookformaster(ntp);
						if (ntp->status == MASTER) {
							masterup(ntp);
							polls = POLLRATE-1;
						}
					}
					if (ntp->status == MASTER
					    && --ntp->quit_count < 0)
						ntp->quit_count = 0;
				}
				if (polls != 0)
					setstatus();
			}

			synch(0L);

			for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
				to.tsp_type = TSP_LOOP;
				to.tsp_vers = TSPVERSION;
				to.tsp_seq = sequence++;
				to.tsp_hopcnt = MAX_HOPCNT;
				(void)strcpy(to.tsp_name, hostname);
				bytenetorder(&to);
				if (sendto(sock, (char *)&to,
					   sizeof(struct tsp), 0,
					   (struct sockaddr*)&ntp->dest_addr,
					   sizeof(ntp->dest_addr)) < 0) {
				   trace_sendto_err(ntp->dest_addr.sin_addr);
				}
			}
		}


	} else {
		switch (msg->tsp_type) {

		case TSP_MASTERREQ:
			break;

		case TSP_SLAVEUP:
			newslave(msg);
			break;

		case TSP_SETDATE:
			/*
			 * XXX check to see it is from ourself
			 */
			tsp_time_sec = msg->tsp_time.tv_sec;
			(void)strcpy(newdate, ctime(&tsp_time_sec));
			if (!good_host_name(msg->tsp_name)) {
				syslog(LOG_NOTICE,
				       "attempted date change by %s to %s",
				       msg->tsp_name, newdate);
				spreadtime();
				break;
			}

			mchgdate(msg);
			(void)gettimeofday(&ntime, 0);
			pollingtime = ntime.tv_sec + SAMPLEINTVL;
			break;

		case TSP_SETDATEREQ:
			if (!fromnet || fromnet->status != MASTER)
				break;
			tsp_time_sec = msg->tsp_time.tv_sec;
			(void)strcpy(newdate, ctime(&tsp_time_sec));
			htp = findhost(msg->tsp_name);
			if (htp == 0) {
				syslog(LOG_ERR,
				       "attempted SET DATEREQ by uncontrolled %s to %s",
				       msg->tsp_name, newdate);
				break;
			}
			if (htp->seq == msg->tsp_seq)
				break;
			htp->seq = msg->tsp_seq;
			if (!htp->good) {
				syslog(LOG_NOTICE,
				"attempted SET DATEREQ by untrusted %s to %s",
				       msg->tsp_name, newdate);
				spreadtime();
				break;
			}

			mchgdate(msg);
			(void)gettimeofday(&ntime, 0);
			pollingtime = ntime.tv_sec + SAMPLEINTVL;
			break;

		case TSP_MSITE:
			xmit(TSP_ACK, msg->tsp_seq, &from);
			break;

		case TSP_MSITEREQ:
			break;

		case TSP_TRACEON:
			traceon();
			break;

		case TSP_TRACEOFF:
			traceoff("Tracing ended at %s\n");
			break;

		case TSP_ELECTION:
			if (!fromnet)
				break;
			if (fromnet->status == MASTER) {
				pollingtime = 0;
				(void)addmach(msg->tsp_name, &from,fromnet);
			}
			taddr = from;
			(void)strcpy(tname, msg->tsp_name);
			to.tsp_type = TSP_QUIT;
			(void)strcpy(to.tsp_name, hostname);
			answer = acksend(&to, &taddr, tname,
					 TSP_ACK, 0, 1);
			if (answer == NULL) {
				syslog(LOG_ERR, "election error by %s",
				       tname);
			}
			break;

		case TSP_CONFLICT:
			/*
			 * After a network partition, there can be
			 * more than one master: the first slave to
			 * come up will notify here the situation.
			 */
			if (!fromnet || fromnet->status != MASTER)
				break;
			(void)strcpy(to.tsp_name, hostname);

			/* The other master often gets into the same state,
			 * with boring results if we stay at it forever.
			 */
			ntp = fromnet;	/* (acksend() can leave fromnet=0 */
			for (i = 0; i < 3; i++) {
				to.tsp_type = TSP_RESOLVE;
				(void)strcpy(to.tsp_name, hostname);
				answer = acksend(&to, &ntp->dest_addr,
						 ANYADDR, TSP_MASTERACK,
						 ntp, 0);
				if (!answer)
					break;
				htp = addmach(answer->tsp_name,&from,ntp);
				to.tsp_type = TSP_QUIT;
				msg = acksend(&to, &htp->addr, htp->name,
					      TSP_ACK, 0, htp->noanswer);
				if (msg == NULL) {
					syslog(LOG_ERR,
				    "no response from %s to CONFLICT-QUIT",
					       htp->name);
				}
			}
			masterup(ntp);
			pollingtime = 0;
			break;

		case TSP_RESOLVE:
			if (!fromnet || fromnet->status != MASTER)
				break;
			/*
			 * do not want to call synch() while waiting
			 * to be killed!
			 */
			(void)gettimeofday(&ntime, (struct timezone *)0);
			pollingtime = ntime.tv_sec + SAMPLEINTVL;
			break;

		case TSP_QUIT:
			doquit(msg);		/* become a slave */
			break;

		case TSP_LOOP:
			if (!fromnet || fromnet->status != MASTER
			    || !strcmp(msg->tsp_name, hostname))
				break;
			/*
			 * We should not have received this from a net
			 * we are master on.  There must be two masters.
			 */
			htp = addmach(msg->tsp_name, &from,fromnet);
			to.tsp_type = TSP_QUIT;
			(void)strcpy(to.tsp_name, hostname);
			answer = acksend(&to, &htp->addr, htp->name,
					 TSP_ACK, 0, 1);
			if (!answer) {
				syslog(LOG_WARNING,
				"loop breakage: no reply from %s=%s to QUIT",
				    htp->name, inet_ntoa(htp->addr.sin_addr));
				(void)remmach(htp);
			}

		case TSP_TEST:
			if (trace) {
				fprintf(fd,
		"\tnets = %d, masters = %d, slaves = %d, ignored = %d\n",
		nnets, nmasternets, nslavenets, nignorednets);
				setstatus();
			}
			pollingtime = 0;
			polls = POLLRATE-1;
			break;

		default:
			if (trace) {
				fprintf(fd, "garbage message: ");
				print(msg, &from);
			}
			break;
		}
	}
	goto loop;
}
Ejemplo n.º 4
0
/* update our image of the net-group of trustworthy hosts
 */
void
get_goodgroup(int force)
{
# define NG_DELAY (30*60*CLK_TCK)	/* 30 minutes */
	static unsigned long last_update = -NG_DELAY;
	unsigned long new_update;
	struct goodhost *ghp, **ghpp;
#ifdef HAVENIS
	struct hosttbl *htp;
	char *mach, *usr, *dom;
#endif /* HAVENIS */
	struct tms tm;


	/* if no netgroup, then we are finished */
	if (goodgroup == NULL || !Mflag)
		return;

	/* Do not chatter with the netgroup master too often.
	 */
	new_update = times(&tm);
	if (new_update < last_update + NG_DELAY
	    && !force)
		return;
	last_update = new_update;

	/* forget the old temporary entries */
	ghpp = &goodhosts;
	while ((ghp = *ghpp) != NULL) {
		if (!ghp->perm) {
			*ghpp = ghp->next;
			free(ghp);
		} else {
			ghpp = &ghp->next;
		}
	}

#ifdef HAVENIS
	/* quit now if we are not one of the trusted masters
	 */
	if (!innetgr(goodgroup, &hostname[0], 0,0)) {
		if (trace)
			(void)fprintf(fd, "get_goodgroup: %s not in %s\n",
				      &hostname[0], goodgroup);
		return;
	}
	if (trace)
		(void)fprintf(fd, "get_goodgroup: %s in %s\n",
				  &hostname[0], goodgroup);

	/* mark the entire netgroup as trusted */
	(void)setnetgrent(goodgroup);
	while (getnetgrent(&mach,&usr,&dom)) {
		if (mach != NULL)
			add_good_host(mach,0);
	}
	(void)endnetgrent();

	/* update list of slaves */
	for (htp = self.l_fwd; htp != &self; htp = htp->l_fwd) {
		htp->good = good_host_name(&htp->name[0]);
	}
#endif /* HAVENIS */
}
Ejemplo n.º 5
0
void
lookformaster(struct netinfo *ntp)
{
	struct tsp resp, conflict, *answer;
	struct timeval ntime;
	char mastername[MAXHOSTNAMELEN];
	struct sockaddr_in masteraddr;

	get_goodgroup(0);
	ntp->status = SLAVE;

	/* look for master */
	resp.tsp_type = TSP_MASTERREQ;
	(void)strcpy(resp.tsp_name, hostname);
	answer = acksend(&resp, &ntp->dest_addr, ANYADDR,
			 TSP_MASTERACK, ntp, 0);
	if (answer != NULL && !good_host_name(answer->tsp_name)) {
		suppress(&from, answer->tsp_name, ntp);
		ntp->status = NOMASTER;
		answer = NULL;
	}
	if (answer == NULL) {
		/*
		 * Various conditions can cause conflict: races between
		 * two just started timedaemons when no master is
		 * present, or timedaemons started during an election.
		 * A conservative approach is taken.  Give up and became a
		 * slave, postponing election of a master until first
		 * timer expires.
		 */
		ntime.tv_sec = ntime.tv_usec = 0;
		answer = readmsg(TSP_MASTERREQ, ANYADDR, &ntime, ntp);
		if (answer != NULL) {
			if (!good_host_name(answer->tsp_name)) {
				suppress(&from, answer->tsp_name, ntp);
				ntp->status = NOMASTER;
			}
			return;
		}

		ntime.tv_sec = ntime.tv_usec = 0;
		answer = readmsg(TSP_MASTERUP, ANYADDR, &ntime, ntp);
		if (answer != NULL) {
			if (!good_host_name(answer->tsp_name)) {
				suppress(&from, answer->tsp_name, ntp);
				ntp->status = NOMASTER;
			}
			return;
		}

		ntime.tv_sec = ntime.tv_usec = 0;
		answer = readmsg(TSP_ELECTION, ANYADDR, &ntime, ntp);
		if (answer != NULL) {
			if (!good_host_name(answer->tsp_name)) {
				suppress(&from, answer->tsp_name, ntp);
				ntp->status = NOMASTER;
			}
			return;
		}

		if (Mflag)
			ntp->status = MASTER;
		else
			ntp->status = NOMASTER;
		return;
	}

	ntp->status = SLAVE;
	(void)strcpy(mastername, answer->tsp_name);
	masteraddr = from;

	/*
	 * If network has been partitioned, there might be other
	 * masters; tell the one we have just acknowledged that
	 * it has to gain control over the others.
	 */
	ntime.tv_sec = 0;
	ntime.tv_usec = 300000;
	answer = readmsg(TSP_MASTERACK, ANYADDR, &ntime, ntp);
	/*
	 * checking also not to send CONFLICT to ack'ed master
	 * due to duplicated MASTERACKs
	 */
	if (answer != NULL &&
	    strcmp(answer->tsp_name, mastername) != 0) {
		conflict.tsp_type = TSP_CONFLICT;
		(void)strcpy(conflict.tsp_name, hostname);
		if (!acksend(&conflict, &masteraddr, mastername,
			     TSP_ACK, 0, 0)) {
			syslog(LOG_ERR,
			       "error on sending TSP_CONFLICT");
		}
	}
}
Ejemplo n.º 6
0
/*
 * add a host to the list of controlled machines if not already there
 */
struct hosttbl *
addmach(char *name, struct sockaddr_in *addr, struct netinfo *ntp)
{
	struct hosttbl *ret, *p, *b, *f;

	ret = findhost(name);
	if (ret == 0) {
		if (slvcount >= NHOSTS) {
			if (trace) {
				fprintf(fd, "no more slots in host table\n");
				prthp(CLK_TCK);
			}
			syslog(LOG_ERR, "no more slots in host table");
			Mflag = 0;
			longjmp(jmpenv, 2); /* give up and be a slave */
		}

		/* if our home hash slot is occupied, find a free entry
		 * in the hash table
		 */
		if (newhost_hash->name[0] != '\0') {
			do {
				ret = lasthfree;
				if (++lasthfree > &hosttbl[NHOSTS])
					lasthfree = &hosttbl[1];
			} while (ret->name[0] != '\0');

			if (!newhost_hash->head) {
				/* Move an interloper using our home.  Use
				 * scratch pointers in case the new head is
				 * pointing to itself.
				 */
				f = newhost_hash->h_fwd;
				b = newhost_hash->h_bak;
				f->h_bak = ret;
				b->h_fwd = ret;
				f = newhost_hash->l_fwd;
				b = newhost_hash->l_bak;
				f->l_bak = ret;
				b->l_fwd = ret;
				bcopy(newhost_hash,ret,sizeof(*ret));
				ret = newhost_hash;
				ret->head = 1;
				ret->h_fwd = ret;
				ret->h_bak = ret;
			} else {
				/* link to an existing chain in our home
				 */
				ret->head = 0;
				p = newhost_hash->h_bak;
				ret->h_fwd = newhost_hash;
				ret->h_bak = p;
				p->h_fwd = ret;
				newhost_hash->h_bak = ret;
			}
		} else {
			ret = newhost_hash;
			ret->head = 1;
			ret->h_fwd = ret;
			ret->h_bak = ret;
		}
		ret->addr = *addr;
		ret->ntp = ntp;
		(void)strncpy(ret->name, name, sizeof(ret->name));
		ret->good = good_host_name(name);
		ret->l_fwd = &self;
		ret->l_bak = self.l_bak;
		self.l_bak->l_fwd = ret;
		self.l_bak = ret;
		slvcount++;

		ret->noanswer = 0;
		ret->need_set = 1;

	} else {
		ret->noanswer = (ret->noanswer != 0);
	}

	/* need to clear sequence number anyhow */
	ret->seq = 0;
	return(ret);
}
Ejemplo n.º 7
0
/*
 * `election' candidates a host as master: it is called by a slave
 * which runs with the -M option set when its election timeout expires.
 * Note the conservative approach: if a new timed comes up, or another
 * candidate sends an election request, the candidature is withdrawn.
 */
int
election(struct netinfo *net)
{
	struct tsp *resp, msg;
	struct timeval then, wait;
	struct tsp *answer;
	struct hosttbl *htp;
	char loop_lim = 0;

/* This code can get totally confused if it gets slightly behind.  For
 *	example, if readmsg() has some QUIT messages waiting from the last
 *	round, we would send an ELECTION message, get the stale QUIT,
 *	and give up.  This results in network storms when several machines
 *	do it at once.
 */
	wait.tv_sec = 0;
	wait.tv_usec = 0;
	while (0 != readmsg(TSP_REFUSE, ANYADDR, &wait, net)) {
		if (trace)
			fprintf(fd, "election: discarded stale REFUSE\n");
	}
	while (0 != readmsg(TSP_QUIT, ANYADDR, &wait, net)) {
		if (trace)
			fprintf(fd, "election: discarded stale QUIT\n");
	}

again:
	syslog(LOG_INFO, "This machine is a candidate time master");
	if (trace)
		fprintf(fd, "This machine is a candidate time master\n");
	msg.tsp_type = TSP_ELECTION;
	msg.tsp_vers = TSPVERSION;
	(void)strcpy(msg.tsp_name, hostname);
	bytenetorder(&msg);
	if (sendto(sock, (char *)&msg, sizeof(struct tsp), 0,
		   (struct sockaddr*)&net->dest_addr,
		   sizeof(struct sockaddr)) < 0) {
		trace_sendto_err(net->dest_addr.sin_addr);
		return(SLAVE);
	}

	(void)gettimeofday(&then, 0);
	then.tv_sec += 3;
	for (;;) {
		(void)gettimeofday(&wait, 0);
		timevalsub(&wait,&then,&wait);
		resp = readmsg(TSP_ANY, ANYADDR, &wait, net);
		if (!resp)
			return(MASTER);

		switch (resp->tsp_type) {

		case TSP_ACCEPT:
			(void)addmach(resp->tsp_name, &from,fromnet);
			break;

		case TSP_MASTERUP:
		case TSP_MASTERREQ:
			/*
			 * If another timedaemon is coming up at the same
			 * time, give up, and let it be the master.
			 */
			if (++loop_lim < 5
			    && !good_host_name(resp->tsp_name)) {
				(void)addmach(resp->tsp_name, &from,fromnet);
				suppress(&from, resp->tsp_name, net);
				goto again;
			}
			rmnetmachs(net);
			return(SLAVE);

		case TSP_QUIT:
		case TSP_REFUSE:
			/*
			 * Collision: change value of election timer
			 * using exponential backoff.
			 *
			 *  Fooey.
			 * An exponential backoff on a delay starting at
			 * 6 to 15 minutes for a process that takes
			 * milliseconds is silly.  It is particularly
			 * strange that the original code would increase
			 * the backoff without bound.
			 */
			rmnetmachs(net);
			return(SLAVE);

		case TSP_ELECTION:
			/* no master for another round */
			htp = addmach(resp->tsp_name,&from,fromnet);
			msg.tsp_type = TSP_REFUSE;
			(void)strcpy(msg.tsp_name, hostname);
			answer = acksend(&msg, &htp->addr, htp->name,
					 TSP_ACK, 0, htp->noanswer);
			if (!answer) {
				syslog(LOG_ERR, "error in election from %s",
				       htp->name);
			}
			break;

		case TSP_SLAVEUP:
			(void)addmach(resp->tsp_name, &from,fromnet);
			break;

		case TSP_SETDATE:
		case TSP_SETDATEREQ:
			break;

		default:
			if (trace) {
				fprintf(fd, "candidate: ");
				print(resp, &from);
			}
			break;
		}
	}
}