slave.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 584 行 · 第 1/2 页

			msg->tsp_type = TSP_SETDATEREQ;
			msg->tsp_vers = TSPVERSION;
			(void)strcpy(msg->tsp_name, hostname);
			for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
				if (ntp->status == SLAVE)
					break;
			}
			if (ntp == NULL)
				break;
			answer = acksend(msg, &ntp->dest_addr, (char *)ANYADDR,
			    TSP_DATEACK, ntp);
			if (answer != NULL) {
				msg->tsp_type = TSP_ACK;
				bytenetorder(msg);
				length = sizeof(struct sockaddr_in);
				if (sendto(sock, (char *)msg,
				    sizeof(struct tsp), 0, &saveaddr,
				    length) < 0) {
					syslog(LOG_ERR, "sendto: %m");
					exit(1);
				}
				senddateack = ON;
			}
			break;
		case TSP_SETDATEREQ:
			saveaddr = from;
			if (status != SUBMASTER || fromnet->status != MASTER)
				break;
			for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
				if (ntp->status == SLAVE)
					break;
			}
			ind = findhost(msg->tsp_name);
			if (ind < 0) {
			    syslog(LOG_WARNING,
				"DATEREQ from uncontrolled machine");
			    break;
			}
			syslog(LOG_DEBUG,
			    "forwarding date change request for %s",
			    msg->tsp_name);
			(void)strcpy(msg->tsp_name, hostname);
			answer = acksend(msg, &ntp->dest_addr, (char *)ANYADDR,
			    TSP_DATEACK, ntp);
			if (answer != NULL) {
				msg->tsp_type = TSP_DATEACK;
				bytenetorder(msg);
				length = sizeof(struct sockaddr_in);
				if (sendto(sock, (char *)msg,
				    sizeof(struct tsp), 0, &saveaddr,
				    length) < 0) {
					syslog(LOG_ERR, "sendto: %m");
					exit(1);
				}
			}
			break;
		case TSP_TRACEON:
			if (!(trace)) {
				fd = fopen(tracefile, "w");
				setlinebuf(fd);
				fprintf(fd, "Tracing started on: %s\n\n", 
								date());
			}
			trace = ON;
			break;
		case TSP_TRACEOFF:
			if (trace) {
				fprintf(fd, "Tracing ended on: %s\n", date());
				(void)fclose(fd);
			}
#ifdef GPROF
			moncontrol(0);
			_mcleanup();
			moncontrol(1);
#endif
			trace = OFF;
			break;
		case TSP_SLAVEUP:
			if ((status & MASTER) && fromnet->status == MASTER) {
				ind = addmach(msg->tsp_name, &from);
				newslave(ind, msg->tsp_seq);
			}
			break;
		case TSP_ELECTION:
			if (fromnet->status == SLAVE) {
				(void)gettimeofday(&time, (struct timezone *)0);
				electiontime = time.tv_sec + delay2;
				seq = 0;            /* reset sequence number */
				if (time.tv_sec < refusetime)
					msg->tsp_type = TSP_REFUSE;
				else {
					msg->tsp_type = TSP_ACCEPT;
					refusetime = time.tv_sec + 30;
				}
				(void)strcpy(candidate, msg->tsp_name);
				(void)strcpy(msg->tsp_name, hostname);
				answerdelay();
				server = from;
				answer = acksend(msg, &server, candidate, TSP_ACK,
				    (struct netinfo *)NULL);
				if (answer == NULL)
					syslog(LOG_WARNING,
					   "no answer from master candidate\n");
			} else {	/* fromnet->status == MASTER */
				to.tsp_type = TSP_QUIT;
				(void)strcpy(to.tsp_name, hostname);
				server = from;
				answer = acksend(&to, &server, msg->tsp_name,
				    TSP_ACK, (struct netinfo *)NULL);
				if (answer == NULL) {
					syslog(LOG_WARNING,
					    "election error: no reply to QUIT");
				} else {
					(void) addmach(msg->tsp_name, &from);
				}
			}
			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.
                         */
                        (void)strcpy(to.tsp_name, hostname);

                        if (fromnet == NULL)
                                break;
                        for(;;) {
                                to.tsp_type = TSP_RESOLVE;
                                answer = acksend(&to, &fromnet->dest_addr,
                                    (char *)ANYADDR, TSP_MASTERACK, fromnet);
                                if (answer == NULL)
                                        break;
                                to.tsp_type = TSP_QUIT;
                                server = from;
                                msg = acksend(&to, &server, answer->tsp_name,
                                    TSP_ACK, (struct netinfo *)NULL);
                                if (msg == NULL) {
                                        syslog(LOG_WARNING,
					    "conflict error: no reply to QUIT");
				} else {
                                        (void) addmach(answer->tsp_name, &from);
				}
                        }
                        masterup(fromnet);
                        break;
		case TSP_MSITE:
			if (!slavenet)
				break;
			msaveaddr = from;
			msg->tsp_type = TSP_MSITEREQ;
			msg->tsp_vers = TSPVERSION;
			(void)strcpy(msg->tsp_name, hostname);
			answer = acksend(msg, &slavenet->dest_addr,
					 (char *)ANYADDR, TSP_ACK, slavenet);
			if (answer != NULL) {
				msg->tsp_type = TSP_ACK;
				length = sizeof(struct sockaddr_in);
				bytenetorder(msg);
				if (sendto(sock, (char *)msg, 
						sizeof(struct tsp), 0,
						&msaveaddr, length) < 0) {
					syslog(LOG_ERR, "sendto: %m");
					exit(1);
				}
			}
			break;
		case TSP_ACCEPT:
		case TSP_REFUSE:
			break;
		case TSP_RESOLVE:
			break;
		case TSP_QUIT:
			/* become slave */
#ifdef MEASURE
			if (fp != NULL) {
				(void)fclose(fp);
				fp = NULL;
			}
#endif
			longjmp(jmpenv, 2);
			break;
#ifdef TESTING
		case TSP_TEST:
			electiontime = 0;
			break;
#endif
		case TSP_MSITEREQ:
			if (status & MASTER)
				break;
			if (trace) {
				fprintf(fd, "garbage: ");
				print(msg, &from);
			}
			break;

		case TSP_LOOP:
			/* looking for loops of masters */
			if ( !(status & MASTER))
				break;
			if (fromnet->status == SLAVE) {
			    if ( !strcmp(msg->tsp_name, hostname)) {
				  for(;;) {
				    to.tsp_type = TSP_RESOLVE;
				    answer = acksend(&to, &fromnet->dest_addr,
					(char *)ANYADDR, TSP_MASTERACK,
					fromnet);
				    if (answer == NULL)
					    break;
				    to.tsp_type = TSP_QUIT;
				    (void)strcpy(to.tsp_name, hostname);
				    server = from;
				    answer = acksend(&to, &server,
					answer->tsp_name, TSP_ACK,
					(struct netinfo *)NULL);
				    if (answer == NULL) {
					syslog(LOG_ERR, "loop kill error");
				    } else {
					electiontime = 0;
				    }
				  }
			    } else {
				if (msg->tsp_hopcnt-- <= 0)
				    break;
				bytenetorder(msg);
				ntp = nettab;
				for (; ntp != NULL; ntp = ntp->next)
				    if (ntp->status == MASTER)
					if (sendto(sock, (char *)msg, 
					    sizeof(struct tsp), 0,
					    &ntp->dest_addr, length) < 0) {
						syslog(LOG_ERR, "sendto: %m");
						exit(1);
					}
			    }
			} else {
			    /*
			     * We should not have received this from a net
			     * we are master on.  There must be two masters
			     * in this case.
			     */
			    if (fromnet->my_addr.s_addr == from.sin_addr.s_addr)
				break;
			    for (;;) {
				to.tsp_type = TSP_RESOLVE;
				answer = acksend(&to, &fromnet->dest_addr,
				    (char *)ANYADDR, TSP_MASTERACK,
				    fromnet);
				if (answer == NULL)
					break;
				to.tsp_type = TSP_QUIT;
				(void)strcpy(to.tsp_name, hostname);
				server = from;
				answer = acksend(&to, &server, answer->tsp_name,
				    TSP_ACK, (struct netinfo *)NULL);
				if (answer == NULL) {
					syslog(LOG_ERR, "loop kill error2");
				} else {
					(void)addmach(msg->tsp_name, &from);
				}
			    }
			}
			break;
		default:
			if (trace) {
				fprintf(fd, "garbage: ");
				print(msg, &from);
			}
			break;
		}
	}
	goto loop;
}

/*
 * Used before answering a broadcast message to avoid network
 * contention and likely collisions.
 */
answerdelay()
{
	struct timeval timeout;

	timeout.tv_sec = 0;
	timeout.tv_usec = delay1;

	(void)select(0, (fd_set *)NULL, (fd_set *)NULL, (fd_set *)NULL,
	    &timeout);
	return;
}