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32 static char sccsid[] = "@(#)candidate.c 8.1 (Berkeley) 6/6/93";
34 static const char rcsid[] =
41 * `election' candidates a host as master: it is called by a slave
42 * which runs with the -M option set when its election timeout expires.
43 * Note the conservative approach: if a new timed comes up, or another
44 * candidate sends an election request, the candidature is withdrawn.
50 struct tsp *resp, msg;
51 struct timeval then, wait;
56 /* This code can get totally confused if it gets slightly behind. For
57 * example, if readmsg() has some QUIT messages waiting from the last
58 * round, we would send an ELECTION message, get the stale QUIT,
59 * and give up. This results in network storms when several machines
64 while (0 != readmsg(TSP_REFUSE, ANYADDR, &wait, net)) {
66 fprintf(fd, "election: discarded stale REFUSE\n");
68 while (0 != readmsg(TSP_QUIT, ANYADDR, &wait, net)) {
70 fprintf(fd, "election: discarded stale QUIT\n");
74 syslog(LOG_INFO, "This machine is a candidate time master");
76 fprintf(fd, "This machine is a candidate time master\n");
77 msg.tsp_type = TSP_ELECTION;
78 msg.tsp_vers = TSPVERSION;
79 (void)strcpy(msg.tsp_name, hostname);
81 if (sendto(sock, (char *)&msg, sizeof(struct tsp), 0,
82 (struct sockaddr*)&net->dest_addr,
83 sizeof(struct sockaddr)) < 0) {
84 trace_sendto_err(net->dest_addr.sin_addr);
88 (void)gettimeofday(&then, 0);
91 (void)gettimeofday(&wait, 0);
92 timevalsub(&wait,&then,&wait);
93 resp = readmsg(TSP_ANY, ANYADDR, &wait, net);
97 switch (resp->tsp_type) {
100 (void)addmach(resp->tsp_name, &from,fromnet);
106 * If another timedaemon is coming up at the same
107 * time, give up, and let it be the master.
110 && !good_host_name(resp->tsp_name)) {
111 (void)addmach(resp->tsp_name, &from,fromnet);
112 suppress(&from, resp->tsp_name, net);
121 * Collision: change value of election timer
122 * using exponential backoff.
125 * An exponential backoff on a delay starting at
126 * 6 to 15 minutes for a process that takes
127 * milliseconds is silly. It is particularly
128 * strange that the original code would increase
129 * the backoff without bound.
135 /* no master for another round */
136 htp = addmach(resp->tsp_name,&from,fromnet);
137 msg.tsp_type = TSP_REFUSE;
138 (void)strcpy(msg.tsp_name, hostname);
139 answer = acksend(&msg, &htp->addr, htp->name,
140 TSP_ACK, 0, htp->noanswer);
142 syslog(LOG_ERR, "error in election from %s",
148 (void)addmach(resp->tsp_name, &from,fromnet);
157 fprintf(fd, "candidate: ");