/* $NetBSD: slave.c,v 1.19 2018/01/16 07:57:58 maya Exp $ */ /*- * 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. 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. */ #include #ifndef lint #if 0 static char sccsid[] = "@(#)slave.c 8.1 (Berkeley) 6/6/93"; #else __RCSID("$NetBSD: slave.c,v 1.19 2018/01/16 07:57:58 maya Exp $"); #endif #endif /* not lint */ #include "globals.h" #include #include "pathnames.h" extern jmp_buf jmpenv; extern int Mflag; extern int justquit; extern u_short sequence; static char master_name[MAXHOSTNAMELEN+1]; static struct netinfo *old_slavenet; static int old_status; static void schgdate(struct tsp *, char *); static void setmaster(struct tsp *); static void answerdelay(void); void slave(void) { int tries; long electiontime, refusetime, looktime, looptime, adjusttime; u_short seq; long fastelection; #define FASTTOUT 3 struct in_addr cadr; struct timeval otime; struct sockaddr_in taddr; char tname[MAXHOSTNAMELEN]; struct tsp *msg, to; struct timeval ntime, wait, tmptv; time_t tmpt; struct tsp *answer; char olddate[32]; char newdate[32]; struct netinfo *ntp; struct hosttbl *htp; memset(&cadr, 0, sizeof(cadr)); /* XXX gcc */ old_slavenet = 0; seq = 0; refusetime = 0; adjusttime = 0; (void)gettimeofday(&ntime, 0); electiontime = ntime.tv_sec + delay2; fastelection = ntime.tv_sec + FASTTOUT; if (justquit) looktime = electiontime; else looktime = fastelection; looptime = fastelection; if (slavenet) xmit(TSP_SLAVEUP, 0, &slavenet->dest_addr); if (status & MASTER) { for (ntp = nettab; ntp != NULL; ntp = ntp->next) { if (ntp->status == MASTER) masterup(ntp); } } loop: get_goodgroup(0); (void)gettimeofday(&ntime, (struct timezone *)0); if (ntime.tv_sec > electiontime) { if (trace) fprintf(fd, "election timer expired\n"); longjmp(jmpenv, 1); } if (ntime.tv_sec >= looktime) { if (trace) fprintf(fd, "Looking for nets to master\n"); if (Mflag && nignorednets > 0) { for (ntp = nettab; ntp != NULL; ntp = ntp->next) { if (ntp->status == IGNORE || ntp->status == NOMASTER) { lookformaster(ntp); if (ntp->status == MASTER) { masterup(ntp); } else if (ntp->status == MASTER) { ntp->status = NOMASTER; } } if (ntp->status == MASTER && --ntp->quit_count < 0) ntp->quit_count = 0; } makeslave(slavenet); /* prune extras */ setstatus(); } (void)gettimeofday(&ntime, 0); looktime = ntime.tv_sec + delay2; } if (ntime.tv_sec >= looptime) { if (trace) fprintf(fd, "Looking for loops\n"); for (ntp = nettab; ntp != NULL; ntp = ntp->next) { if (ntp->status == MASTER) { to.tsp_type = TSP_LOOP; to.tsp_vers = TSPVERSION; to.tsp_seq = sequence++; to.tsp_hopcnt = MAX_HOPCNT; set_tsp_name(&to, hostname); bytenetorder(&to); (void)sendtsp(sock, &to, &ntp->dest_addr); } } (void)gettimeofday(&ntime, 0); looptime = ntime.tv_sec + delay2; } wait.tv_sec = min(electiontime,min(looktime,looptime)) - ntime.tv_sec; if (wait.tv_sec < 0) wait.tv_sec = 0; wait.tv_sec += FASTTOUT; wait.tv_usec = 0; msg = readmsg(TSP_ANY, ANYADDR, &wait, 0); if (msg != NULL) { /* * filter stuff not for us */ switch (msg->tsp_type) { case TSP_SETDATE: case TSP_TRACEOFF: case TSP_TRACEON: /* * XXX check to see they are from ourself */ break; case TSP_TEST: case TSP_MSITE: break; case TSP_MASTERUP: if (!fromnet) { if (trace) { fprintf(fd, "slave ignored: "); print(msg, &from); } goto loop; } break; default: if (!fromnet || fromnet->status == IGNORE || fromnet->status == NOMASTER) { if (trace) { fprintf(fd, "slave ignored: "); print(msg, &from); } goto loop; } break; } /* * now process the message */ switch (msg->tsp_type) { case TSP_ADJTIME: if (fromnet != slavenet) break; if (!good_host_name(msg->tsp_name)) { syslog(LOG_NOTICE, "attempted time adjustment by %s", msg->tsp_name); suppress(&from, msg->tsp_name, fromnet); break; } /* * Speed up loop detection in case we have a loop. * Otherwise the clocks can race until the loop * is found. */ (void)gettimeofday(&otime, 0); if (adjusttime < otime.tv_sec) looptime -= (looptime-otime.tv_sec)/2 + 1; setmaster(msg); if (seq != msg->tsp_seq) { seq = msg->tsp_seq; synch((long)tvtomsround(msg->tsp_time)); } (void)gettimeofday(&ntime, 0); electiontime = ntime.tv_sec + delay2; fastelection = ntime.tv_sec + FASTTOUT; adjusttime = ntime.tv_sec + SAMPLEINTVL*2; break; case TSP_SETTIME: if (fromnet != slavenet) break; if (seq == msg->tsp_seq) break; seq = msg->tsp_seq; /* adjust time for residence on the queue */ (void)gettimeofday(&otime, 0); adj_msg_time(msg,&otime); /* * the following line is necessary due to syslog * calling ctime() which clobbers the static buffer */ (void)strlcpy(olddate, date(), sizeof(olddate)); tmpt = msg->tsp_time.tv_sec; (void)strlcpy(newdate, ctime(&tmpt), sizeof(newdate)); if (!good_host_name(msg->tsp_name)) { syslog(LOG_NOTICE, "attempted time setting by untrusted %s to %s", msg->tsp_name, newdate); suppress(&from, msg->tsp_name, fromnet); break; } setmaster(msg); timersub(&msg->tsp_time, &otime, &ntime); if (ntime.tv_sec < MAXADJ && ntime.tv_sec > -MAXADJ) { /* * do not change the clock if we can adjust it */ synch(tvtomsround(ntime)); } else { update_time(&tmptv, msg); syslog(LOG_NOTICE, "date changed by %s from %s", msg->tsp_name, olddate); if (status & MASTER) spreadtime(); } (void)gettimeofday(&ntime, 0); electiontime = ntime.tv_sec + delay2; fastelection = ntime.tv_sec + FASTTOUT; /* This patches a bad protocol bug. Imagine a system with several networks, * where there are a pair of redundant gateways between a pair of networks, * each running timed. Assume that we start with a third machine mastering * one of the networks, and one of the gateways mastering the other. * Imagine that the third machine goes away and the non-master gateway * decides to replace it. If things are timed just 'right,' we will have * each gateway mastering one network for a little while. If a SETTIME * message gets into the network at that time, perhaps from the newly * masterful gateway as it was taking control, the SETTIME will loop * forever. Each time a gateway receives it on its slave side, it will * call spreadtime to forward it on its mastered network. We are now in * a permanent loop, since the SETTIME msgs will keep any clock * in the network from advancing. Normally, the 'LOOP' stuff will detect * and correct the situation. However, with the clocks stopped, the * 'looptime' timer cannot expire. While they are in this state, the * masters will try to saturate the network with SETTIME packets. */ looptime = ntime.tv_sec + (looptime-otime.tv_sec)/2-1; break; case TSP_MASTERUP: if (slavenet && fromnet != slavenet) break; if (!good_host_name(msg->tsp_name)) { suppress(&from, msg->tsp_name, fromnet); if (electiontime > fastelection) electiontime = fastelection; break; } makeslave(fromnet); setmaster(msg); setstatus(); answerdelay(); xmit(TSP_SLAVEUP, 0, &from); (void)gettimeofday(&ntime, 0); electiontime = ntime.tv_sec + delay2; fastelection = ntime.tv_sec + FASTTOUT; refusetime = 0; break; case TSP_MASTERREQ: if (fromnet->status != SLAVE) break; (void)gettimeofday(&ntime, 0); electiontime = ntime.tv_sec + delay2; break; case TSP_SETDATE: tmpt = msg->tsp_time.tv_sec; (void)strlcpy(newdate, ctime(&tmpt), sizeof(newdate)); schgdate(msg, newdate); break; case TSP_SETDATEREQ: if (fromnet->status != MASTER) break; tmpt = msg->tsp_time.tv_sec; (void)strlcpy(newdate, ctime(&tmpt), sizeof(newdate)); htp = findhost(msg->tsp_name); if (0 == htp) { syslog(LOG_WARNING, "DATEREQ from uncontrolled machine"); break; } if (!htp->good) { syslog(LOG_WARNING, "attempted date change by untrusted %s to %s", htp->name, newdate); spreadtime(); break; } schgdate(msg, newdate); break; case TSP_TRACEON: traceon(); break; case TSP_TRACEOFF: traceoff("Tracing ended at %s\n"); break; case TSP_SLAVEUP: newslave(msg); break; case TSP_ELECTION: if (fromnet->status == SLAVE) { (void)gettimeofday(&ntime, 0); electiontime = ntime.tv_sec + delay2; fastelection = ntime.tv_sec + FASTTOUT; seq = 0; if (!good_host_name(msg->tsp_name)) { syslog(LOG_NOTICE, "suppress election of %s", msg->tsp_name); to.tsp_type = TSP_QUIT; electiontime = fastelection; } else if (cadr.s_addr != from.sin_addr.s_addr && ntime.tv_sec < refusetime) { /* if the candidate has to repeat itself, the old code would refuse it * the second time. That would prevent elections. */ to.tsp_type = TSP_REFUSE; } else { cadr.s_addr = from.sin_addr.s_addr; to.tsp_type = TSP_ACCEPT; refusetime = ntime.tv_sec + 30; } taddr = from; get_tsp_name(msg, tname, sizeof(tname)); set_tsp_name(&to, hostname); answerdelay(); if (!acksend(&to, &taddr, tname, TSP_ACK, 0, 0)) syslog(LOG_WARNING, "no answer from candidate %s\n", tname); } else { /* fromnet->status == MASTER */ htp = addmach(msg->tsp_name, &from,fromnet); to.tsp_type = TSP_QUIT; set_tsp_name(&to, hostname); if (!acksend(&to, &htp->addr, htp->name, TSP_ACK, 0, htp->noanswer)) { syslog(LOG_ERR, "no reply from %s to ELECTION-QUIT", htp->name); (void)remmach(htp); } } break; case TSP_CONFLICT: if (fromnet->status != MASTER) break; /* * After a network partition, there can be * more than one master: the first slave to * come up will notify here the situation. */ set_tsp_name(&to, hostname); /* The other master often gets into the same state, * with boring results. */ ntp = fromnet; /* (acksend() can leave fromnet=0 */ for (tries = 0; tries < 3; tries++) { to.tsp_type = TSP_RESOLVE; answer = acksend(&to, &ntp->dest_addr, ANYADDR, TSP_MASTERACK, ntp, 0); if (answer == NULL) break; htp = addmach(answer->tsp_name,&from,ntp); to.tsp_type = TSP_QUIT; answer = acksend(&to, &htp->addr, htp->name, TSP_ACK, 0, htp->noanswer); if (!answer) { syslog(LOG_WARNING, "conflict error: no reply from %s to QUIT", htp->name); (void)remmach(htp); } } masterup(ntp); break; case TSP_MSITE: if (!slavenet) break; taddr = from; to.tsp_type = TSP_MSITEREQ; to.tsp_vers = TSPVERSION; to.tsp_seq = 0; set_tsp_name(&to, hostname); answer = acksend(&to, &slavenet->dest_addr, ANYADDR, TSP_ACK, slavenet, 0); if (answer != NULL && good_host_name(answer->tsp_name)) { setmaster(answer); to.tsp_type = TSP_ACK; set_tsp_name(&to, answer->tsp_name); bytenetorder(&to); (void)sendtsp(sock, &to, &taddr); } break; case TSP_MSITEREQ: break; case TSP_ACCEPT: case TSP_REFUSE: case TSP_RESOLVE: break; case TSP_QUIT: doquit(msg); /* become a slave */ break; case TSP_TEST: electiontime = 0; break; case TSP_LOOP: /* looking for loops of masters */ if (!(status & MASTER)) break; if (fromnet->status == SLAVE) { if (!strcmp(msg->tsp_name, hostname)) { /* * Someone forwarded our message back to * us. There must be a loop. Tell the * master of this network to quit. * * The other master often gets into * the same state, with boring results. */ ntp = fromnet; for (tries = 0; tries < 3; tries++) { to.tsp_type = TSP_RESOLVE; answer = acksend(&to, &ntp->dest_addr, ANYADDR, TSP_MASTERACK, ntp,0); if (answer == NULL) break; taddr = from; get_tsp_name(answer, tname, sizeof(tname)); to.tsp_type = TSP_QUIT; set_tsp_name(&to, hostname); if (!acksend(&to, &taddr, tname, TSP_ACK, 0, 1)) { syslog(LOG_ERR, "no reply from %s to slave LOOP-QUIT", tname); } else { electiontime = 0; } } (void)gettimeofday(&ntime, 0); looptime = ntime.tv_sec + FASTTOUT; } else { if (msg->tsp_hopcnt-- < 1) break; bytenetorder(msg); for (ntp = nettab; ntp != 0; ntp = ntp->next) { if (ntp->status == MASTER) (void)sendtsp(sock, msg, &ntp->dest_addr); } } } else { /* fromnet->status == MASTER */ /* * We should not have received this from a net * we are master on. There must be two masters, * unless the packet was really from us. */ if (from.sin_addr.s_addr == fromnet->my_addr.s_addr) { if (trace) fprintf(fd,"discarding forwarded LOOP\n"); break; } /* * The other master often gets into the same * state, with boring results. */ ntp = fromnet; for (tries = 0; tries < 3; tries++) { to.tsp_type = TSP_RESOLVE; answer = acksend(&to, &ntp->dest_addr, ANYADDR, TSP_MASTERACK, ntp,0); if (!answer) break; htp = addmach(answer->tsp_name, &from,ntp); to.tsp_type = TSP_QUIT; set_tsp_name(&to, hostname); if (!acksend(&to,&htp->addr,htp->name, TSP_ACK, 0, htp->noanswer)) { syslog(LOG_ERR, "no reply from %s to master LOOP-QUIT", htp->name); (void)remmach(htp); } } (void)gettimeofday(&ntime, 0); looptime = ntime.tv_sec + FASTTOUT; } break; default: if (trace) { fprintf(fd, "garbage message: "); print(msg, &from); } break; } } goto loop; } /* * tell the world who our master is */ static void setmaster(struct tsp *msg) { if (slavenet && (slavenet != old_slavenet || strcmp(msg->tsp_name, master_name) || old_status != status)) { get_tsp_name(msg, master_name, sizeof(master_name)); old_slavenet = slavenet; old_status = status; if (status & MASTER) { syslog(LOG_NOTICE, "submaster to %s", master_name); if (trace) fprintf(fd, "submaster to %s\n", master_name); } else { syslog(LOG_NOTICE, "slave to %s", master_name); if (trace) fprintf(fd, "slave to %s\n", master_name); } } } /* * handle date change request on a slave */ static void schgdate(struct tsp *msg, char *newdate) { struct tsp to; u_short seq; struct sockaddr_in taddr; struct timeval otime; if (!slavenet) return; /* no where to forward */ taddr = from; seq = msg->tsp_seq; syslog(LOG_INFO, "forwarding date change by %s to %s", msg->tsp_name, newdate); /* adjust time for residence on the queue */ (void)gettimeofday(&otime, 0); adj_msg_time(msg, &otime); to.tsp_type = TSP_SETDATEREQ; to.tsp_time = msg->tsp_time; set_tsp_name(&to, hostname); if (!acksend(&to, &slavenet->dest_addr, ANYADDR, TSP_DATEACK, slavenet, 0)) return; /* no answer */ xmit(TSP_DATEACK, seq, &taddr); } /* * Used before answering a broadcast message to avoid network * contention and likely collisions. */ static void answerdelay(void) { struct timespec timeout; timeout.tv_sec = 0; timeout.tv_nsec = delay1 * 1000; nanosleep(&timeout, NULL); return; }