1/*- 2 * Copyright (c) 1985, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#ifndef lint 35#if 0 36static char sccsid[] = "@(#)candidate.c 8.1 (Berkeley) 6/6/93"; 37#endif 38__attribute__((__used__)) 39static const char rcsid[] = 40 "$FreeBSD: src/usr.sbin/timed/timed/candidate.c,v 1.5 1999/08/28 01:20:16 peter Exp $"; 41#endif /* not lint */ 42#include <sys/cdefs.h> 43 44#include "globals.h" 45 46/* 47 * `election' candidates a host as master: it is called by a slave 48 * which runs with the -M option set when its election timeout expires. 49 * Note the conservative approach: if a new timed comes up, or another 50 * candidate sends an election request, the candidature is withdrawn. 51 */ 52int 53election(net) 54 struct netinfo *net; 55{ 56 struct tsp *resp, msg; 57 struct timeval then, wait; 58 struct tsp *answer; 59 struct hosttbl *htp; 60 char loop_lim = 0; 61 62/* This code can get totally confused if it gets slightly behind. For 63 * example, if readmsg() has some QUIT messages waiting from the last 64 * round, we would send an ELECTION message, get the stale QUIT, 65 * and give up. This results in network storms when several machines 66 * do it at once. 67 */ 68 wait.tv_sec = 0; 69 wait.tv_usec = 0; 70 while (0 != readmsg(TSP_REFUSE, ANYADDR, &wait, net)) { 71 if (trace) 72 fprintf(fd, "election: discarded stale REFUSE\n"); 73 } 74 while (0 != readmsg(TSP_QUIT, ANYADDR, &wait, net)) { 75 if (trace) 76 fprintf(fd, "election: discarded stale QUIT\n"); 77 } 78 79again: 80 syslog(LOG_INFO, "This machine is a candidate time master"); 81 if (trace) 82 fprintf(fd, "This machine is a candidate time master\n"); 83 msg.tsp_type = TSP_ELECTION; 84 msg.tsp_vers = TSPVERSION; 85 (void)strcpy(msg.tsp_name, hostname); 86 bytenetorder(&msg); 87 if (sendto(sock, (char *)&msg, sizeof(struct tsp), 0, 88 (struct sockaddr*)&net->dest_addr, 89 sizeof(struct sockaddr)) < 0) { 90 trace_sendto_err(net->dest_addr.sin_addr); 91 return(SLAVE); 92 } 93 94 (void)gettimeofday(&then, 0); 95 then.tv_sec += 3; 96 for (;;) { 97 (void)gettimeofday(&wait, 0); 98 timevalsub(&wait,&then,&wait); 99 resp = readmsg(TSP_ANY, ANYADDR, &wait, net); 100 if (!resp) 101 return(MASTER); 102 103 switch (resp->tsp_type) { 104 105 case TSP_ACCEPT: 106 (void)addmach(resp->tsp_name, &from,fromnet); 107 break; 108 109 case TSP_MASTERUP: 110 case TSP_MASTERREQ: 111 /* 112 * If another timedaemon is coming up at the same 113 * time, give up, and let it be the master. 114 */ 115 if (++loop_lim < 5 116 && !good_host_name(resp->tsp_name)) { 117 (void)addmach(resp->tsp_name, &from,fromnet); 118 suppress(&from, resp->tsp_name, net); 119 goto again; 120 } 121 rmnetmachs(net); 122 return(SLAVE); 123 124 case TSP_QUIT: 125 case TSP_REFUSE: 126 /* 127 * Collision: change value of election timer 128 * using exponential backoff. 129 * 130 * Fooey. 131 * An exponential backoff on a delay starting at 132 * 6 to 15 minutes for a process that takes 133 * milliseconds is silly. It is particularly 134 * strange that the original code would increase 135 * the backoff without bound. 136 */ 137 rmnetmachs(net); 138 return(SLAVE); 139 140 case TSP_ELECTION: 141 /* no master for another round */ 142 htp = addmach(resp->tsp_name,&from,fromnet); 143 msg.tsp_type = TSP_REFUSE; 144 (void)strcpy(msg.tsp_name, hostname); 145 answer = acksend(&msg, &htp->addr, htp->name, 146 TSP_ACK, 0, htp->noanswer); 147 if (!answer) { 148 syslog(LOG_ERR, "error in election from %s", 149 htp->name); 150 } 151 break; 152 153 case TSP_SLAVEUP: 154 (void)addmach(resp->tsp_name, &from,fromnet); 155 break; 156 157 case TSP_SETDATE: 158 case TSP_SETDATEREQ: 159 break; 160 161 default: 162 if (trace) { 163 fprintf(fd, "candidate: "); 164 print(resp, &from); 165 } 166 break; 167 } 168 } 169} 170