440 lines
9.9 KiB
C
440 lines
9.9 KiB
C
/*
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* The mrouted program is covered by the license in the accompanying file
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* named "LICENSE". Use of the mrouted program represents acceptance of
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* the terms and conditions listed in that file.
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*
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* The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
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* Leland Stanford Junior University.
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*
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*
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* $Id: main.c,v 1.8 1994/08/24 23:53:42 thyagara Exp $
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*/
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/*
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* Written by Steve Deering, Stanford University, February 1989.
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*
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* (An earlier version of DVMRP was implemented by David Waitzman of
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* BBN STC by extending Berkeley's routed program. Some of Waitzman's
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* extensions have been incorporated into mrouted, but none of the
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* original routed code has been adopted.)
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*/
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#include "defs.h"
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extern char *configfilename;
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static char pidfilename[] = "/etc/mrouted.pid";
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static char dumpfilename[] = "/usr/tmp/mrouted.dump";
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static char cachefilename[] = "/usr/tmp/mrouted.cache";
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static char genidfilename[] = "/usr/tmp/mrouted.genid";
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int cache_lifetime = DEFAULT_CACHE_LIFETIME;
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int max_prune_lifetime = DEFAULT_CACHE_LIFETIME * 2;
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int debug = 0;
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u_char pruning = 1; /* Enable pruning by default */
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/*
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* Forward declarations.
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*/
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static void fasttimer();
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static void timer();
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static void hup();
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static void dump();
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static void fdump();
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static void cdump();
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static void restart();
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main(argc, argv)
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int argc;
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char *argv[];
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{
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register int recvlen;
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register int omask;
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int dummy;
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FILE *fp;
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extern uid_t geteuid();
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struct timeval tv;
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struct timezone tzp;
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u_long prev_genid;
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setlinebuf(stderr);
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if (geteuid() != 0) {
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fprintf(stderr, "must be root\n");
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exit(1);
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}
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argv++, argc--;
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while (argc > 0 && *argv[0] == '-') {
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if (strcmp(*argv, "-d") == 0) {
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if (argc > 1 && isdigit(*(argv + 1)[0])) {
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argv++, argc--;
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debug = atoi(*argv);
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} else
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debug = DEFAULT_DEBUG;
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} else if (strcmp(*argv, "-c") == 0) {
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if (argc > 1) {
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argv++, argc--;
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configfilename = *argv;
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} else
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goto usage;
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} else if (strcmp(*argv, "-p") == 0) {
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pruning = 0;
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} else
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goto usage;
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argv++, argc--;
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}
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if (argc > 0) {
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usage: fprintf(stderr,
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"usage: mrouted [-p] [-c configfile] [-d [debug_level]]\n");
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exit(1);
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}
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if (debug == 0) {
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/*
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* Detach from the terminal
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*/
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int t;
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if (fork()) exit(0);
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(void)close(0);
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(void)close(1);
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(void)close(2);
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(void)open("/", 0);
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(void)dup2(0, 1);
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(void)dup2(0, 2);
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t = open("/dev/tty", 2);
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if (t >= 0) {
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(void)ioctl(t, TIOCNOTTY, (char *)0);
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(void)close(t);
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}
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}
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else
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fprintf(stderr, "debug level %u\n", debug);
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#ifdef LOG_DAEMON
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(void)openlog("mrouted", LOG_PID, LOG_DAEMON);
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(void)setlogmask(LOG_UPTO(LOG_NOTICE));
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#else
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(void)openlog("mrouted", LOG_PID);
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#endif
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log(LOG_NOTICE, 0, "mrouted version %d.%d",
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PROTOCOL_VERSION, MROUTED_VERSION);
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srandom(gethostid());
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/*
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* Get generation id
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*/
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gettimeofday(&tv, &tzp);
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dvmrp_genid = tv.tv_sec;
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fp = fopen(genidfilename, "r");
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if (fp != NULL) {
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fscanf(fp, "%d", &prev_genid);
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if (prev_genid == dvmrp_genid)
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dvmrp_genid++;
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(void) fclose(fp);
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}
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fp = fopen(genidfilename, "w");
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if (fp != NULL) {
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fprintf(fp, "%d", dvmrp_genid);
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(void) fclose(fp);
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}
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callout_init();
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init_igmp();
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k_init_dvmrp(); /* enable DVMRP routing in kernel */
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init_routes();
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init_ktable();
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init_vifs();
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if (debug)
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fprintf(stderr, "pruning %s\n", pruning ? "on" : "off");
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fp = fopen(pidfilename, "w");
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if (fp != NULL) {
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fprintf(fp, "%d\n", getpid());
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(void) fclose(fp);
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}
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if (debug >= 2) dump();
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(void)signal(SIGALRM, fasttimer);
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(void)signal(SIGHUP, restart);
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(void)signal(SIGTERM, hup);
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(void)signal(SIGINT, hup);
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(void)signal(SIGUSR1, fdump);
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(void)signal(SIGUSR2, cdump);
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if (debug != 0)
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(void)signal(SIGQUIT, dump);
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(void)alarm(1); /* schedule first timer interrupt */
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/*
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* Main receive loop.
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*/
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dummy = 0;
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for(;;) {
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recvlen = recvfrom(igmp_socket, recv_buf, sizeof(recv_buf),
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0, NULL, &dummy);
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if (recvlen < 0) {
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if (errno != EINTR) log(LOG_ERR, errno, "recvfrom");
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continue;
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}
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omask = sigblock(sigmask(SIGALRM));
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accept_igmp(recvlen);
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(void)sigsetmask(omask);
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}
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}
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/*
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* routine invoked every second. It's main goal is to cycle through
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* the routing table and send partial updates to all neighbors at a
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* rate that will cause the entire table to be sent in ROUTE_REPORT_INTERVAL
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* seconds. Also, every TIMER_INTERVAL seconds it calls timer() to
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* do all the other time-based processing.
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*/
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static void fasttimer()
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{
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static unsigned int tlast;
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static unsigned int nsent;
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register unsigned int t = tlast + 1;
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register int n;
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/*
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* if we're in the last second, send everything that's left.
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* otherwise send at least the fraction we should have sent by now.
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*/
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if (t >= ROUTE_REPORT_INTERVAL) {
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register int nleft = nroutes - nsent;
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while (nleft > 0) {
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if ((n = report_next_chunk()) <= 0)
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break;
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nleft -= n;
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}
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tlast = 0;
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nsent = 0;
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} else {
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register unsigned int ncum = nroutes * t / ROUTE_REPORT_INTERVAL;
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while (nsent < ncum) {
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if ((n = report_next_chunk()) <= 0)
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break;
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nsent += n;
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}
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tlast = t;
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}
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if ((t % TIMER_INTERVAL) == 0)
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timer();
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age_callout_queue();/* Advance the timer for the callout queue
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for groups */
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alarm(1);
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}
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/*
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* The 'virtual_time' variable is initialized to a value that will cause the
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* first invocation of timer() to send a probe or route report to all vifs
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* and send group membership queries to all subnets for which this router is
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* querier. This first invocation occurs approximately TIMER_INTERVAL seconds
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* after the router starts up. Note that probes for neighbors and queries
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* for group memberships are also sent at start-up time, as part of initial-
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* ization. This repetition after a short interval is desirable for quickly
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* building up topology and membership information in the presence of possible
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* packet loss.
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*
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* 'virtual_time' advances at a rate that is only a crude approximation of
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* real time, because it does not take into account any time spent processing,
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* and because the timer intervals are sometimes shrunk by a random amount to
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* avoid unwanted synchronization with other routers.
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*/
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static u_long virtual_time = 0;
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/*
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* Timer routine. Performs periodic neighbor probing, route reporting, and
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* group querying duties, and drives various timers in routing entries and
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* virtual interface data structures.
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*/
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static void timer()
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{
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age_routes(); /* Advance the timers in the route entries */
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age_vifs(); /* Advance the timers for neighbors */
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age_table_entry(); /* Advance the timers for the cache entries */
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if (virtual_time % GROUP_QUERY_INTERVAL == 0) {
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/*
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* Time to query the local group memberships on all subnets
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* for which this router is the elected querier.
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*/
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query_groups();
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}
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if (virtual_time % NEIGHBOR_PROBE_INTERVAL == 0) {
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/*
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* Time to send a probe on all vifs from which no neighbors have
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* been heard. Also, check if any inoperative interfaces have now
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* come up. (If they have, they will also be probed as part of
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* their initialization.)
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*/
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probe_for_neighbors();
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if (vifs_down)
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check_vif_state();
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}
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delay_change_reports = FALSE;
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if (routes_changed) {
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/*
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* Some routes have changed since the last timer interrupt, but
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* have not been reported yet. Report the changed routes to all
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* neighbors.
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*/
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report_to_all_neighbors(CHANGED_ROUTES);
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}
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/*
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* Advance virtual time
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*/
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virtual_time += TIMER_INTERVAL;
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}
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/*
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* On hangup signal, let everyone know we're going away.
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*/
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static void hup()
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{
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log(LOG_INFO, 0, "hup");
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expire_all_routes();
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report_to_all_neighbors(ALL_ROUTES);
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exit(1);
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}
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/*
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* Dump internal data structures to stderr.
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*/
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static void dump()
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{
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dump_vifs(stderr);
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dump_routes(stderr);
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}
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/*
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* Dump internal data structures to a file.
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*/
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static void fdump()
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{
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FILE *fp;
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fp = fopen(dumpfilename, "w");
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if (fp != NULL) {
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dump_vifs(fp);
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dump_routes(fp);
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(void) fclose(fp);
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}
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}
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/*
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* Dump local cache contents to a file.
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*/
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static void cdump()
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{
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FILE *fp;
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fp = fopen(cachefilename, "w");
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if (fp != NULL) {
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dump_cache(fp);
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(void) fclose(fp);
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}
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}
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/*
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* Restart mrouted
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*/
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static void restart()
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{
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register int omask;
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log(LOG_INFO, 0, "restart");
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/*
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* reset all the entries
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*/
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omask = sigblock(sigmask(SIGALRM));
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free_all_prunes();
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free_all_routes();
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stop_all_vifs();
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k_stop_dvmrp();
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/*
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* start processing again
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*/
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dvmrp_genid++;
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pruning = 1;
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init_igmp();
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k_init_dvmrp(); /* enable DVMRP routing in kernel */
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init_routes();
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init_ktable();
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init_vifs();
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(void)sigsetmask(omask);
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}
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/*
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* Log errors and other messages to the system log daemon and to stderr,
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* according to the severity of the message and the current debug level.
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* For errors of severity LOG_ERR or worse, terminate the program.
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*/
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void log(severity, syserr, format, a, b, c, d, e)
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int severity, syserr;
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char *format;
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int a, b, c, d, e;
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{
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char fmt[100];
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switch (debug) {
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case 0: break;
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case 1: if (severity > LOG_NOTICE) break;
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case 2: if (severity > LOG_INFO ) break;
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default:
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fmt[0] = '\0';
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if (severity == LOG_WARNING) strcat(fmt, "warning - ");
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strncat(fmt, format, 80);
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fprintf(stderr, fmt, a, b, c, d, e);
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if (syserr == 0)
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fprintf(stderr, "\n");
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else if(syserr < sys_nerr)
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fprintf(stderr, ": %s\n", sys_errlist[syserr]);
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else
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fprintf(stderr, ": errno %d\n", syserr);
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}
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if (severity <= LOG_NOTICE) {
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fmt[0] = '\0';
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if (severity == LOG_WARNING) strcat(fmt, "warning - ");
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strncat(fmt, format, 80);
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if (syserr != 0) {
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strcat(fmt, ": %m");
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errno = syserr;
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}
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syslog(severity, fmt, a, b, c, d, e);
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if (severity <= LOG_ERR) exit(-1);
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}
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}
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