/* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /*- * 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 static char sccsid[] = "@(#)candidate.c 8.1 (Berkeley) 6/6/93"; #endif /* not lint */ #ifdef sgi #ident "$Revision: 1.1.1.1 $" #endif #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; } } }