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36 static char sccsid[] = "@(#)candidate.c 8.1 (Berkeley) 6/6/93";
38 static const char rcsid[] =
45 * `election' candidates a host as master: it is called by a slave
46 * which runs with the -M option set when its election timeout expires.
47 * Note the conservative approach: if a new timed comes up, or another
48 * candidate sends an election request, the candidature is withdrawn.
54 struct tsp *resp, msg;
55 struct timeval then, wait;
60 /* This code can get totally confused if it gets slightly behind. For
61 * example, if readmsg() has some QUIT messages waiting from the last
62 * round, we would send an ELECTION message, get the stale QUIT,
63 * and give up. This results in network storms when several machines
68 while (0 != readmsg(TSP_REFUSE, ANYADDR, &wait, net)) {
70 fprintf(fd, "election: discarded stale REFUSE\n");
72 while (0 != readmsg(TSP_QUIT, ANYADDR, &wait, net)) {
74 fprintf(fd, "election: discarded stale QUIT\n");
78 syslog(LOG_INFO, "This machine is a candidate time master");
80 fprintf(fd, "This machine is a candidate time master\n");
81 msg.tsp_type = TSP_ELECTION;
82 msg.tsp_vers = TSPVERSION;
83 (void)strcpy(msg.tsp_name, hostname);
85 if (sendto(sock, (char *)&msg, sizeof(struct tsp), 0,
86 (struct sockaddr*)&net->dest_addr,
87 sizeof(struct sockaddr)) < 0) {
88 trace_sendto_err(net->dest_addr.sin_addr);
92 (void)gettimeofday(&then, 0);
95 (void)gettimeofday(&wait, 0);
96 timevalsub(&wait,&then,&wait);
97 resp = readmsg(TSP_ANY, ANYADDR, &wait, net);
101 switch (resp->tsp_type) {
104 (void)addmach(resp->tsp_name, &from,fromnet);
110 * If another timedaemon is coming up at the same
111 * time, give up, and let it be the master.
114 && !good_host_name(resp->tsp_name)) {
115 (void)addmach(resp->tsp_name, &from,fromnet);
116 suppress(&from, resp->tsp_name, net);
125 * Collision: change value of election timer
126 * using exponential backoff.
129 * An exponential backoff on a delay starting at
130 * 6 to 15 minutes for a process that takes
131 * milliseconds is silly. It is particularly
132 * strange that the original code would increase
133 * the backoff without bound.
139 /* no master for another round */
140 htp = addmach(resp->tsp_name,&from,fromnet);
141 msg.tsp_type = TSP_REFUSE;
142 (void)strcpy(msg.tsp_name, hostname);
143 answer = acksend(&msg, &htp->addr, htp->name,
144 TSP_ACK, 0, htp->noanswer);
146 syslog(LOG_ERR, "error in election from %s",
152 (void)addmach(resp->tsp_name, &from,fromnet);
161 fprintf(fd, "candidate: ");