1281681Srpaulo/*- 2281681Srpaulo * Copyright (c) 1985, 1993 3281681Srpaulo * The Regents of the University of California. All rights reserved. 4281681Srpaulo * 5281681Srpaulo * Redistribution and use in source and binary forms, with or without 6281681Srpaulo * modification, are permitted provided that the following conditions 7281681Srpaulo * are met: 8281681Srpaulo * 1. Redistributions of source code must retain the above copyright 9281681Srpaulo * notice, this list of conditions and the following disclaimer. 10281681Srpaulo * 2. Redistributions in binary form must reproduce the above copyright 11281681Srpaulo * notice, this list of conditions and the following disclaimer in the 12281681Srpaulo * documentation and/or other materials provided with the distribution. 13281681Srpaulo * 4. Neither the name of the University nor the names of its contributors 14281681Srpaulo * may be used to endorse or promote products derived from this software 15281681Srpaulo * without specific prior written permission. 16281681Srpaulo * 17281681Srpaulo * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18281681Srpaulo * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19281681Srpaulo * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20281681Srpaulo * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21281681Srpaulo * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22281681Srpaulo * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23281681Srpaulo * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24281681Srpaulo * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25281681Srpaulo * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26281681Srpaulo * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27281681Srpaulo * SUCH DAMAGE. 28281681Srpaulo */ 29281681Srpaulo 30281681Srpaulo#ifndef lint 31281681Srpaulo#if 0 32281681Srpaulostatic char sccsid[] = "@(#)candidate.c 8.1 (Berkeley) 6/6/93"; 33281681Srpaulo#endif 34281681Srpaulostatic const char rcsid[] = 35281681Srpaulo "$FreeBSD$"; 36281681Srpaulo#endif /* not lint */ 37281681Srpaulo 38281681Srpaulo#include "globals.h" 39281681Srpaulo 40281681Srpaulo/* 41281681Srpaulo * `election' candidates a host as master: it is called by a slave 42281681Srpaulo * which runs with the -M option set when its election timeout expires. 43281681Srpaulo * Note the conservative approach: if a new timed comes up, or another 44281681Srpaulo * candidate sends an election request, the candidature is withdrawn. 45281681Srpaulo */ 46281681Srpauloint 47281681Srpauloelection(net) 48281681Srpaulo struct netinfo *net; 49281681Srpaulo{ 50281681Srpaulo struct tsp *resp, msg; 51281681Srpaulo struct timeval then, wait; 52281681Srpaulo struct tsp *answer; 53281681Srpaulo struct hosttbl *htp; 54281681Srpaulo char loop_lim = 0; 55281681Srpaulo 56281681Srpaulo/* This code can get totally confused if it gets slightly behind. For 57281681Srpaulo * example, if readmsg() has some QUIT messages waiting from the last 58281681Srpaulo * round, we would send an ELECTION message, get the stale QUIT, 59281681Srpaulo * and give up. This results in network storms when several machines 60281681Srpaulo * do it at once. 61281681Srpaulo */ 62281681Srpaulo wait.tv_sec = 0; 63281681Srpaulo wait.tv_usec = 0; 64281681Srpaulo while (0 != readmsg(TSP_REFUSE, ANYADDR, &wait, net)) { 65281681Srpaulo if (trace) 66281681Srpaulo fprintf(fd, "election: discarded stale REFUSE\n"); 67281681Srpaulo } 68281681Srpaulo while (0 != readmsg(TSP_QUIT, ANYADDR, &wait, net)) { 69281681Srpaulo if (trace) 70281681Srpaulo fprintf(fd, "election: discarded stale QUIT\n"); 71281681Srpaulo } 72281681Srpaulo 73281681Srpauloagain: 74281681Srpaulo syslog(LOG_INFO, "This machine is a candidate time master"); 75281681Srpaulo if (trace) 76281681Srpaulo fprintf(fd, "This machine is a candidate time master\n"); 77281681Srpaulo msg.tsp_type = TSP_ELECTION; 78281681Srpaulo msg.tsp_vers = TSPVERSION; 79281681Srpaulo (void)strcpy(msg.tsp_name, hostname); 80281681Srpaulo bytenetorder(&msg); 81281681Srpaulo if (sendto(sock, (char *)&msg, sizeof(struct tsp), 0, 82281681Srpaulo (struct sockaddr*)&net->dest_addr, 83281681Srpaulo sizeof(struct sockaddr)) < 0) { 84281681Srpaulo trace_sendto_err(net->dest_addr.sin_addr); 85281681Srpaulo return(SLAVE); 86281681Srpaulo } 87281681Srpaulo 88281681Srpaulo (void)gettimeofday(&then, 0); 89281681Srpaulo then.tv_sec += 3; 90281681Srpaulo for (;;) { 91281681Srpaulo (void)gettimeofday(&wait, 0); 92281681Srpaulo timevalsub(&wait,&then,&wait); 93281681Srpaulo resp = readmsg(TSP_ANY, ANYADDR, &wait, net); 94281681Srpaulo if (!resp) 95281681Srpaulo return(MASTER); 96281681Srpaulo 97281681Srpaulo switch (resp->tsp_type) { 98281681Srpaulo 99281681Srpaulo case TSP_ACCEPT: 100281681Srpaulo (void)addmach(resp->tsp_name, &from,fromnet); 101281681Srpaulo break; 102281681Srpaulo 103281681Srpaulo case TSP_MASTERUP: 104281681Srpaulo case TSP_MASTERREQ: 105281681Srpaulo /* 106281681Srpaulo * If another timedaemon is coming up at the same 107281681Srpaulo * time, give up, and let it be the master. 108281681Srpaulo */ 109281681Srpaulo if (++loop_lim < 5 110281681Srpaulo && !good_host_name(resp->tsp_name)) { 111281681Srpaulo (void)addmach(resp->tsp_name, &from,fromnet); 112281681Srpaulo suppress(&from, resp->tsp_name, net); 113281681Srpaulo goto again; 114281681Srpaulo } 115281681Srpaulo rmnetmachs(net); 116281681Srpaulo return(SLAVE); 117281681Srpaulo 118281681Srpaulo case TSP_QUIT: 119281681Srpaulo case TSP_REFUSE: 120281681Srpaulo /* 121281681Srpaulo * Collision: change value of election timer 122281681Srpaulo * using exponential backoff. 123281681Srpaulo * 124281681Srpaulo * Fooey. 125281681Srpaulo * An exponential backoff on a delay starting at 126281681Srpaulo * 6 to 15 minutes for a process that takes 127281681Srpaulo * milliseconds is silly. It is particularly 128281681Srpaulo * strange that the original code would increase 129281681Srpaulo * the backoff without bound. 130281681Srpaulo */ 131281681Srpaulo rmnetmachs(net); 132281681Srpaulo return(SLAVE); 133281681Srpaulo 134281681Srpaulo case TSP_ELECTION: 135281681Srpaulo /* no master for another round */ 136281681Srpaulo htp = addmach(resp->tsp_name,&from,fromnet); 137281681Srpaulo msg.tsp_type = TSP_REFUSE; 138281681Srpaulo (void)strcpy(msg.tsp_name, hostname); 139281681Srpaulo answer = acksend(&msg, &htp->addr, htp->name, 140281681Srpaulo TSP_ACK, 0, htp->noanswer); 141281681Srpaulo if (!answer) { 142281681Srpaulo syslog(LOG_ERR, "error in election from %s", 143281681Srpaulo htp->name); 144281681Srpaulo } 145281681Srpaulo break; 146281681Srpaulo 147281681Srpaulo case TSP_SLAVEUP: 148281681Srpaulo (void)addmach(resp->tsp_name, &from,fromnet); 149281681Srpaulo break; 150281681Srpaulo 151281681Srpaulo case TSP_SETDATE: 152281681Srpaulo case TSP_SETDATEREQ: 153281681Srpaulo break; 154281681Srpaulo 155281681Srpaulo default: 156281681Srpaulo if (trace) { 157281681Srpaulo fprintf(fd, "candidate: "); 158281681Srpaulo print(resp, &from); 159281681Srpaulo } 160281681Srpaulo break; 161281681Srpaulo } 162281681Srpaulo } 163281681Srpaulo} 164281681Srpaulo