NetBSD/usr.sbin/mrouted/main.c

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/*
* The mrouted program is covered by the license in the accompanying file
* named "LICENSE". Use of the mrouted program represents acceptance of
* the terms and conditions listed in that file.
*
* The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
* Leland Stanford Junior University.
*
*
* from: Id: main.c,v 1.5 1993/06/24 05:11:16 deering Exp
*/
/*
* Written by Steve Deering, Stanford University, February 1989.
*
* (An earlier version of DVMRP was implemented by David Waitzman of
* BBN STC by extending Berkeley's routed program. Some of Waitzman's
* extensions have been incorporated into mrouted, but none of the
* original routed code has been adopted.)
*/
#ifndef lint
static char rcsid[] = "$Id: main.c,v 1.1 1994/01/11 20:15:58 brezak Exp $";
#endif
#include "defs.h"
extern char *configfilename;
static char pidfilename[] = _PATH_MROUTED_PID;
static char dumpfilename[] = _PATH_MROUTED_DUMP;
static int debug = 0;
/*
* Forward declarations.
*/
static void timer();
static void hup();
static void dump();
static void fdump();
main(argc, argv)
int argc;
char *argv[];
{
register int recvlen;
register int omask;
int dummy;
FILE *fp;
extern uid_t geteuid();
setlinebuf(stderr);
if (geteuid() != 0) {
fprintf(stderr, "mrouted: must be root\n");
exit(1);
}
argv++, argc--;
while (argc > 0 && *argv[0] == '-') {
if (strcmp(*argv, "-d") == 0) {
if (argc > 1 && isdigit(*(argv + 1)[0])) {
argv++, argc--;
debug = atoi(*argv);
} else
debug = DEFAULT_DEBUG;
} else if (strcmp(*argv, "-c") == 0) {
if (argc > 1) {
argv++, argc--;
configfilename = *argv;
} else
goto usage;
} else
goto usage;
argv++, argc--;
}
if (argc > 0) {
usage: fprintf(stderr, "usage: mrouted [-c configfile] [-d [debug_level]]\n");
exit(1);
}
if (debug == 0) {
/*
* Detach from the terminal
*/
int t;
if (fork()) exit(0);
(void)close(0);
(void)close(1);
(void)close(2);
(void)open("/", 0);
(void)dup2(0, 1);
(void)dup2(0, 2);
t = open("/dev/tty", 2);
if (t >= 0) {
(void)ioctl(t, TIOCNOTTY, (char *)0);
(void)close(t);
}
}
else fprintf(stderr, "debug level %u\n", debug);
#ifdef LOG_DAEMON
(void)openlog("mrouted", LOG_PID, LOG_DAEMON);
(void)setlogmask(LOG_UPTO(LOG_NOTICE));
#else
(void)openlog("mrouted", LOG_PID);
#endif
log(LOG_NOTICE, 0, "mrouted version %d.%d",
PROTOCOL_VERSION, MROUTED_VERSION);
fp = fopen(pidfilename, "w");
if (fp != NULL) {
fprintf(fp, "%d\n", getpid());
(void) fclose(fp);
}
srandom(gethostid());
init_igmp();
k_init_dvmrp(); /* enable DVMRP routing in kernel */
init_routes();
init_vifs();
if (debug >= 2) dump();
(void)signal(SIGALRM, timer);
(void)signal(SIGHUP, hup);
(void)signal(SIGTERM, hup);
(void)signal(SIGINT, hup);
(void)signal(SIGUSR1, fdump);
if (debug != 0)
(void)signal(SIGQUIT, dump);
(void)alarm(TIMER_INTERVAL); /* schedule first timer interrupt */
/*
* Main receive loop.
*/
dummy = 0;
for(;;) {
recvlen = recvfrom(igmp_socket, recv_buf, sizeof(recv_buf),
0, NULL, &dummy);
if (recvlen < 0) {
if (errno != EINTR) log(LOG_ERR, errno, "recvfrom");
continue;
}
omask = sigblock(sigmask(SIGALRM));
accept_igmp(recvlen);
(void)sigsetmask(omask);
}
}
/*
* The 'virtual_time' variable is initialized to a value that will cause the
* first invocation of timer() to send a probe or route report to all vifs
* and send group membership queries to all subnets for which this router is
* querier. This first invocation occurs approximately TIMER_INTERVAL seconds
* after the router starts up. Note that probes for neighbors and queries
* for group memberships are also sent at start-up time, as part of initial-
* ization. This repetition after a short interval is desirable for quickly
* building up topology and membership information in the presence of possible
* packet loss.
*
* 'virtual_time' advances at a rate that is only a crude approximation of
* real time, because it does not take into account any time spent processing,
* and because the timer intervals are sometimes shrunk by a random amount to
* avoid unwanted synchronization with other routers.
*/
static u_long virtual_time = 0;
/*
* Timer routine. Performs periodic neighbor probing, route reporting, and
* group querying duties, and drives various timers in routing entries and
* virtual interface data structures.
*/
static void timer()
{
int next_interval;
age_routes(); /* Advance the timers in the route entries */
age_vifs(); /* Advance the timers for neighbors and groups */
if (virtual_time % GROUP_QUERY_INTERVAL == 0) {
/*
* Time to query the local group memberships on all subnets
* for which this router is the elected querier.
*/
query_groups();
}
if (virtual_time % NEIGHBOR_PROBE_INTERVAL == 0) {
/*
* Time to send a probe on all vifs from which no neighbors have
* been heard. Also, check if any inoperative interfaces have now
* come up. (If they have, they will also be probed as part of
* their initialization.)
*/
probe_for_neighbors();
if (vifs_down)
check_vif_state();
}
delay_change_reports = FALSE;
next_interval = TIMER_INTERVAL;
if (virtual_time % ROUTE_REPORT_INTERVAL == 0) {
/*
* Time for the periodic report of all routes to all neighbors.
*/
report_to_all_neighbors(ALL_ROUTES);
/*
* Schedule the next timer interrupt for a random time between
* 1 and TIMER_INTERVAL seconds from now. This randomization is
* intended to counteract the undesirable synchronizing tendency
* of periodic transmissions from multiple sources.
*/
next_interval = (random() % TIMER_INTERVAL) + 1;
}
else if (routes_changed) {
/*
* Some routes have changed since the last timer interrupt, but
* have not been reported yet. Report the changed routes to all
* neighbors.
*/
report_to_all_neighbors(CHANGED_ROUTES);
}
/*
* Advance virtual time and schedule the next timer interrupt.
*/
virtual_time += TIMER_INTERVAL;
(void)alarm(next_interval);
}
/*
* On hangup signal, let everyone know we're going away.
*/
static void hup()
{
log(LOG_INFO, 0, "hup");
expire_all_routes();
report_to_all_neighbors(ALL_ROUTES);
exit(1);
}
/*
* Dump internal data structures to stderr.
*/
static void dump()
{
dump_vifs(stderr);
dump_routes(stderr);
}
/*
* Dump internal data structures to a file.
*/
static void fdump()
{
FILE *fp;
fp = fopen(dumpfilename, "w");
if (fp != NULL) {
dump_vifs(fp);
dump_routes(fp);
(void) fclose(fp);
}
}
/*
* Log errors and other messages to the system log daemon and to stderr,
* according to the severity of the message and the current debug level.
* For errors of severity LOG_ERR or worse, terminate the program.
*/
void log(severity, syserr, format, a, b, c, d, e)
int severity, syserr;
char *format;
int a, b, c, d, e;
{
char fmt[100];
switch (debug) {
case 0: break;
case 1: if (severity > LOG_NOTICE) break;
case 2: if (severity > LOG_INFO ) break;
default:
fmt[0] = '\0';
if (severity == LOG_WARNING) strcat(fmt, "warning - ");
strncat(fmt, format, 80);
fprintf(stderr, fmt, a, b, c, d, e);
if (syserr == 0)
fprintf(stderr, "\n");
else if(syserr < sys_nerr)
fprintf(stderr, ": %s\n", sys_errlist[syserr]);
else
fprintf(stderr, ": errno %d\n", syserr);
}
if (severity <= LOG_NOTICE) {
fmt[0] = '\0';
if (severity == LOG_WARNING) strcat(fmt, "warning - ");
strncat(fmt, format, 80);
if (syserr != 0) {
strcat(fmt, ": %m");
errno = syserr;
}
syslog(severity, fmt, a, b, c, d, e);
if (severity <= LOG_ERR) exit(-1);
}
}