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/*-
* 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
#if 0
static char sccsid[] = "@(#)candidate.c 8.1 (Berkeley) 6/6/93";
#endif
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include "globals.h"
/*
* `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* candidate sends an election request, the candidature is withdrawn.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(net)
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;
}
}
}
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