text: /*
   * Copyright (c) 1983, 1988, 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 acknowledgment:
   *	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.
   *
   * $FreeBSD: src/sbin/routed/main.c,v 1.11.2.1 2000/08/14 17:00:03 sheldonh Exp $
   * $DragonFly: src/sbin/routed/main.c,v 1.4 2005/03/16 21:21:34 cpressey Exp $
   */
  
  #include "defs.h"
  #include "pathnames.h"
  #ifdef sgi
  #include "math.h"
  #endif
  #include <signal.h>
  #include <fcntl.h>
  #include <sys/file.h>
  
  #if !defined(sgi) && !defined(__NetBSD__)
  char copyright[] =
  "@(#) Copyright (c) 1983, 1988, 1993\n\
  	The Regents of the University of California.  All rights reserved.\n";
  static char sccsid[] __attribute__((unused)) = "@(#)main.c	8.1 (Berkeley) 6/5/93";
  #elif defined(__NetBSD__)
  __RCSID("$NetBSD$");
  __COPYRIGHT("@(#) Copyright (c) 1983, 1988, 1993\n\
  	The Regents of the University of California.  All rights reserved.\n");
  #endif
  
  
  pid_t	mypid;
  
  naddr	myaddr;				/* system address */
  char	myname[MAXHOSTNAMELEN+1];
  
  int	verbose;
  
  int	supplier;			/* supply or broadcast updates */
  int	supplier_set;
  int	ipforwarding = 1;		/* kernel forwarding on */
  
  int	default_gateway;		/* 1=advertise default */
  int	background = 1;
  int	ridhosts;			/* 1=reduce host routes */
  int	mhome;				/* 1=want multi-homed host route */
  int	advertise_mhome;		/* 1=must continue advertising it */
  int	auth_ok = 1;			/* 1=ignore auth if we do not care */
  
  struct timeval epoch;			/* when started */
  struct timeval clk, prev_clk;
  static int usec_fudge;
  struct timeval now;			/* current idea of time */
  time_t	now_stale;
  time_t	now_expire;
  time_t	now_garbage;
  
  struct timeval next_bcast;		/* next general broadcast */
  struct timeval no_flash = {		/* inhibit flash update */
  	EPOCH+SUPPLY_INTERVAL, 0
  };
  
  struct timeval flush_kern_timer;
  
  fd_set	fdbits;
  int	sock_max;
  int	rip_sock = -1;			/* RIP socket */
  struct interface *rip_sock_mcast;	/* current multicast interface */
  int	rt_sock;			/* routing socket */
  int	rt_sock_seqno;
  
  
  static  int get_rip_sock(naddr, int);
  static void timevalsub(struct timeval *, struct timeval *, struct timeval *);
  
  int
  main(int argc,
       char *argv[])
  {
  	int n, mib[4], off;
  	size_t len;
  	char *p, *q;
  	const char *cp;
  	struct timeval wtime, t2;
  	time_t dt;
  	fd_set ibits;
  	naddr p_net, p_mask;
  	struct interface *ifp;
  	struct parm parm;
  	char *tracename = 0;
  
  
  	/* Some shells are badly broken and send SIGHUP to backgrounded
  	 * processes.
  	 */
  	signal(SIGHUP, SIG_IGN);
  
  	openlog("routed", LOG_PID | LOG_ODELAY, LOG_DAEMON);
  	ftrace = stdout;
  
  	gettimeofday(&clk, 0);
  	prev_clk = clk;
  	epoch = clk;
  	epoch.tv_sec -= EPOCH;
  	now.tv_sec = EPOCH;
  	now_stale = EPOCH - STALE_TIME;
  	now_expire = EPOCH - EXPIRE_TIME;
  	now_garbage = EPOCH - GARBAGE_TIME;
  	wtime.tv_sec = 0;
  
  	gethostname(myname, sizeof(myname)-1);
  	gethost(myname, &myaddr);
  
  	while ((n = getopt(argc, argv, "sqdghmpAtvT:F:P:")) != -1) {
  		switch (n) {
  		case 's':
  			supplier = 1;
  			supplier_set = 1;
  			break;
  
  		case 'q':
  			supplier = 0;
  			supplier_set = 1;
  			break;
  
  		case 'd':
  			background = 0;
  			break;
  
  		case 'g':
  			memset(&parm, 0, sizeof(parm));
  			parm.parm_d_metric = 1;
  			cp = check_parms(&parm);
  			if (cp != 0)
  				msglog("bad -g: %s", cp);
  			else
  				default_gateway = 1;
  			break;
  
  		case 'h':		/* suppress extra host routes */
  			ridhosts = 1;
  			break;
  
  		case 'm':		/* advertise host route */
  			mhome = 1;	/* on multi-homed hosts */
  			break;
  
  		case 'A':
  			/* Ignore authentication if we do not care.
  			 * Crazy as it is, that is what RFC 1723 requires.
  			 */
  			auth_ok = 0;
  			break;
  
  		case 't':
  			new_tracelevel++;
  			break;
  
  		case 'T':
  			tracename = optarg;
  			break;
  
  		case 'F':		/* minimal routes for SLIP */
  			n = FAKE_METRIC;
  			p = strchr(optarg,',');
  			if (p && *p != '\0') {
  				n = (int)strtoul(p+1, &q, 0);
  				if (*q == '\0'
  				    && n <= HOPCNT_INFINITY-1
  				    && n >= 1)
  					*p = '\0';
  			}
  			if (!getnet(optarg, &p_net, &p_mask)) {
  				msglog("bad network; \"-F %s\"",
  				       optarg);
  				break;
  			}
  			memset(&parm, 0, sizeof(parm));
  			parm.parm_net = p_net;
  			parm.parm_mask = p_mask;
  			parm.parm_d_metric = n;
  			cp = check_parms(&parm);
  			if (cp != 0)
  				msglog("bad -F: %s", cp);
  			break;
  
  		case 'P':
  			/* handle arbitrary parameters.
  			 */
  			q = strdup(optarg);
  			cp = parse_parms(q, 0);
  			if (cp != 0)
  				msglog("%s in \"-P %s\"", cp, optarg);
  			free(q);
  			break;
  
  		case 'v':
  			/* display version */
  			verbose++;
  			msglog("version 2.22");
  			break;
  
  		default:
  			goto usage;
  		}
  	}
  	argc -= optind;
  	argv += optind;
  
  	if (tracename == 0 && argc >= 1) {
  		tracename = *argv++;
  		argc--;
  	}
  	if (tracename != 0 && tracename[0] == '\0')
  		goto usage;
  	if (argc != 0) {
  usage:
  		logbad(0, "usage: routed [-sqdghmpAtv] [-T tracefile]"
  		       " [-F net[,metric]] [-P parms]");
  	}
  	if (geteuid() != 0) {
  		if (verbose)
  			exit(0);
  		logbad(0, "requires UID 0");
  	}
  
  	mib[0] = CTL_NET;
  	mib[1] = PF_INET;
  	mib[2] = IPPROTO_IP;
  	mib[3] = IPCTL_FORWARDING;
  	len = sizeof(ipforwarding);
  	if (sysctl(mib, 4, &ipforwarding, &len, 0, 0) < 0)
  		LOGERR("sysctl(IPCTL_FORWARDING)");
  
  	if (!ipforwarding) {
  		if (supplier)
  			msglog("-s incompatible with ipforwarding=0");
  		if (default_gateway) {
  			msglog("-g incompatible with ipforwarding=0");
  			default_gateway = 0;
  		}
  		supplier = 0;
  		supplier_set = 1;
  	}
  	if (default_gateway) {
  		if (supplier_set && !supplier) {
  			msglog("-g and -q incompatible");
  		} else {
  			supplier = 1;
  			supplier_set = 1;
  		}
  	}
  
  
  	signal(SIGALRM, sigalrm);
  	if (!background)
  		signal(SIGHUP, sigterm);    /* SIGHUP fatal during debugging */
  	signal(SIGTERM, sigterm);
  	signal(SIGINT, sigterm);
  	signal(SIGUSR1, sigtrace_on);
  	signal(SIGUSR2, sigtrace_off);
  
  	/* get into the background */
  #ifdef sgi
  	if (0 > _daemonize(background ? 0 : (_DF_NOCHDIR|_DF_NOFORK),
  			   STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO))
  		BADERR(0, "_daemonize()");
  #else
  	if (background && daemon(0, 1) < 0)
  		BADERR(0,"daemon()");
  #endif
  
  	mypid = getpid();
  	srandom((int)(clk.tv_sec ^ clk.tv_usec ^ mypid));
  
  	/* prepare socket connected to the kernel.
  	 */
  	rt_sock = socket(AF_ROUTE, SOCK_RAW, 0);
  	if (rt_sock < 0)
  		BADERR(1,"rt_sock = socket()");
  	if (fcntl(rt_sock, F_SETFL, O_NONBLOCK) == -1)
  		logbad(1, "fcntl(rt_sock) O_NONBLOCK: %s", strerror(errno));
  	off = 0;
  	if (setsockopt(rt_sock, SOL_SOCKET,SO_USELOOPBACK,
  		       &off,sizeof(off)) < 0)
  		LOGERR("setsockopt(SO_USELOOPBACK,0)");
  
  	fix_select();
  
  
  	if (tracename != 0) {
  		strncpy(inittracename, tracename, sizeof(inittracename)-1);
  		set_tracefile(inittracename, "%s", -1);
  	} else {
  		tracelevel_msg("%s", -1);   /* turn on tracing to stdio */
  	}
  
  	bufinit();
  
  	/* initialize radix tree */
  	rtinit();
  
  	/* Pick a random part of the second for our output to minimize
  	 * collisions.
  	 *
  	 * Start broadcasting after hearing from other routers, and
  	 * at a random time so a bunch of systems do not get synchronized
  	 * after a power failure.
  	 */
  	intvl_random(&next_bcast, EPOCH+MIN_WAITTIME, EPOCH+SUPPLY_INTERVAL);
  	age_timer.tv_usec = next_bcast.tv_usec;
  	age_timer.tv_sec = EPOCH+MIN_WAITTIME;
  	rdisc_timer = next_bcast;
  	ifinit_timer.tv_usec = next_bcast.tv_usec;
  
  	/* Collect an initial view of the world by checking the interface
  	 * configuration and the kludge file.
  	 */
  	gwkludge();
  	ifinit();
  
  	/* Ask for routes */
  	rip_query();
  	rdisc_sol();
  
  	/* Now turn off stdio if not tracing */
  	if (new_tracelevel == 0)
  		trace_close(background);
  
  	/* Loop forever, listening and broadcasting.
  	 */
  	for (;;) {
  		prev_clk = clk;
  		gettimeofday(&clk, 0);
  		if (prev_clk.tv_sec == clk.tv_sec
  		    && prev_clk.tv_usec == clk.tv_usec+usec_fudge) {
  			/* Much of `routed` depends on time always advancing.
  			 * On systems that do not guarantee that gettimeofday()
  			 * produces unique timestamps even if called within
  			 * a single tick, use trickery like that in classic
  			 * BSD kernels.
  			 */
  			clk.tv_usec += ++usec_fudge;
  
  		} else {
  			usec_fudge = 0;
  
  			timevalsub(&t2, &clk, &prev_clk);
  			if (t2.tv_sec < 0
  			    || t2.tv_sec > wtime.tv_sec + 5) {
  				/* Deal with time changes before other
  				 * housekeeping to keep everything straight.
  				 */
  				dt = t2.tv_sec;
  				if (dt > 0)
  					dt -= wtime.tv_sec;
  				trace_act("time changed by %d sec", (int)dt);
  				epoch.tv_sec += dt;
  			}
  		}
  		timevalsub(&now, &clk, &epoch);
  		now_stale = now.tv_sec - STALE_TIME;
  		now_expire = now.tv_sec - EXPIRE_TIME;
  		now_garbage = now.tv_sec - GARBAGE_TIME;
  
  		/* deal with signals that should affect tracing */
  		set_tracelevel();
  
  		if (stopint != 0) {
  			rip_bcast(0);
  			rdisc_adv();
  			trace_off("exiting with signal %d", stopint);
  			exit(stopint | 128);
  		}
  
  		/* look for new or dead interfaces */
  		timevalsub(&wtime, &ifinit_timer, &now);
  		if (wtime.tv_sec <= 0) {
  			wtime.tv_sec = 0;
  			ifinit();
  			rip_query();
  			continue;
  		}
  
  		/* Check the kernel table occassionally for mysteriously
  		 * evaporated routes
  		 */
  		timevalsub(&t2, &flush_kern_timer, &now);
  		if (t2.tv_sec <= 0) {
  			flush_kern();
  			flush_kern_timer.tv_sec = (now.tv_sec
  						   + CHECK_QUIET_INTERVAL);
  			continue;
  		}
  		if (timercmp(&t2, &wtime, <))
  			wtime = t2;
  
  		/* If it is time, then broadcast our routes.
  		 */
  		if (supplier || advertise_mhome) {
  			timevalsub(&t2, &next_bcast, &now);
  			if (t2.tv_sec <= 0) {
  				/* Synchronize the aging and broadcast
  				 * timers to minimize awakenings
  				 */
  				age(0);
  
  				rip_bcast(0);
  
  				/* It is desirable to send routing updates
  				 * regularly.  So schedule the next update
  				 * 30 seconds after the previous one was
  				 * scheduled, instead of 30 seconds after
  				 * the previous update was finished.
  				 * Even if we just started after discovering
  				 * a 2nd interface or were otherwise delayed,
  				 * pick a 30-second aniversary of the
  				 * original broadcast time.
  				 */
  				n = 1 + (0-t2.tv_sec)/SUPPLY_INTERVAL;
  				next_bcast.tv_sec += n*SUPPLY_INTERVAL;
  
  				continue;
  			}
  
  			if (timercmp(&t2, &wtime, <))
  				wtime = t2;
  		}
  
  		/* If we need a flash update, either do it now or
  		 * set the delay to end when it is time.
  		 *
  		 * If we are within MIN_WAITTIME seconds of a full update,
  		 * do not bother.
  		 */
  		if (need_flash
  		    && supplier
  		    && no_flash.tv_sec+MIN_WAITTIME < next_bcast.tv_sec) {
  			/* accurate to the millisecond */
  			if (!timercmp(&no_flash, &now, >))
  				rip_bcast(1);
  			timevalsub(&t2, &no_flash, &now);
  			if (timercmp(&t2, &wtime, <))
  				wtime = t2;
  		}
  
  		/* trigger the main aging timer.
  		 */
  		timevalsub(&t2, &age_timer, &now);
  		if (t2.tv_sec <= 0) {
  			age(0);
  			continue;
  		}
  		if (timercmp(&t2, &wtime, <))
  			wtime = t2;
  
  		/* update the kernel routing table
  		 */
  		timevalsub(&t2, &need_kern, &now);
  		if (t2.tv_sec <= 0) {
  			age(0);
  			continue;
  		}
  		if (timercmp(&t2, &wtime, <))
  			wtime = t2;
  
  		/* take care of router discovery,
  		 * but do it in the correct the millisecond
  		 */
  		if (!timercmp(&rdisc_timer, &now, >)) {
  			rdisc_age(0);
  			continue;
  		}
  		timevalsub(&t2, &rdisc_timer, &now);
  		if (timercmp(&t2, &wtime, <))
  			wtime = t2;
  
  
  		/* wait for input or a timer to expire.
  		 */
  		trace_flush();
  		ibits = fdbits;
  		n = select(sock_max, &ibits, 0, 0, &wtime);
  		if (n <= 0) {
  			if (n < 0 && errno != EINTR && errno != EAGAIN)
  				BADERR(1,"select");
  			continue;
  		}
  
  		if (FD_ISSET(rt_sock, &ibits)) {
  			read_rt();
  			n--;
  		}
  		if (rdisc_sock >= 0 && FD_ISSET(rdisc_sock, &ibits)) {
  			read_d();
  			n--;
  		}
  		if (rip_sock >= 0 && FD_ISSET(rip_sock, &ibits)) {
  			read_rip(rip_sock, 0);
  			n--;
  		}
  
  		for (ifp = ifnet; n > 0 && 0 != ifp; ifp = ifp->int_next) {
  			if (ifp->int_rip_sock >= 0
  			    && FD_ISSET(ifp->int_rip_sock, &ibits)) {
  				read_rip(ifp->int_rip_sock, ifp);
  				n--;
  			}
  		}
  	}
  }
  
  
  /* ARGSUSED */
  void
  sigalrm(int s UNUSED)
  {
  	/* Historically, SIGALRM would cause the daemon to check for
  	 * new and broken interfaces.
  	 */
  	ifinit_timer.tv_sec = now.tv_sec;
  	trace_act("SIGALRM");
  }
  
  
  /* watch for fatal signals */
  void
  sigterm(int sig)
  {
  	stopint = sig;
  	signal(sig, SIG_DFL);	/* catch it only once */
  }
  
  
  void
  fix_select(void)
  {
  	struct interface *ifp;
  
  
  	FD_ZERO(&fdbits);
  	sock_max = 0;
  
  	FD_SET(rt_sock, &fdbits);
  	if (sock_max <= rt_sock)
  		sock_max = rt_sock+1;
  	if (rip_sock >= 0) {
  		FD_SET(rip_sock, &fdbits);
  		if (sock_max <= rip_sock)
  			sock_max = rip_sock+1;
  	}
  	for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
  		if (ifp->int_rip_sock >= 0) {
  			FD_SET(ifp->int_rip_sock, &fdbits);
  			if (sock_max <= ifp->int_rip_sock)
  				sock_max = ifp->int_rip_sock+1;
  		}
  	}
  	if (rdisc_sock >= 0) {
  		FD_SET(rdisc_sock, &fdbits);
  		if (sock_max <= rdisc_sock)
  			sock_max = rdisc_sock+1;
  	}
  }
  
  
  void
  fix_sock(int sock,
  	 const char *name)
  {
  	int on;
  #define MIN_SOCKBUF (4*1024)
  	static int rbuf;
  
  	if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1)
  		logbad(1, "fcntl(%s) O_NONBLOCK: %s",
  		       name, strerror(errno));
  	on = 1;
  	if (setsockopt(sock, SOL_SOCKET,SO_BROADCAST, &on,sizeof(on)) < 0)
  		msglog("setsockopt(%s,SO_BROADCAST): %s",
  		       name, strerror(errno));
  #ifdef USE_PASSIFNAME
  	on = 1;
  	if (setsockopt(sock, SOL_SOCKET, SO_PASSIFNAME, &on,sizeof(on)) < 0)
  		msglog("setsockopt(%s,SO_PASSIFNAME): %s",
  		       name, strerror(errno));
  #endif
  
  	if (rbuf >= MIN_SOCKBUF) {
  		if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
  			       &rbuf, sizeof(rbuf)) < 0)
  			msglog("setsockopt(%s,SO_RCVBUF=%d): %s",
  			       name, rbuf, strerror(errno));
  	} else {
  		for (rbuf = 60*1024; ; rbuf -= 4096) {
  			if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
  				       &rbuf, sizeof(rbuf)) == 0) {
  				trace_act("RCVBUF=%d", rbuf);
  				break;
  			}
  			if (rbuf < MIN_SOCKBUF) {
  				msglog("setsockopt(%s,SO_RCVBUF = %d): %s",
  				       name, rbuf, strerror(errno));
  				break;
  			}
  		}
  	}
  }
  
  
  /* get a rip socket
   */
  static int				/* <0 or file descriptor */
  get_rip_sock(naddr addr,
  	     int serious)		/* 1=failure to bind is serious */
  {
  	struct sockaddr_in in;
  	unsigned char ttl;
  	int s;
  
  
  	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
  		BADERR(1,"rip_sock = socket()");
  
  	memset(&in, 0, sizeof(in));
  #ifdef _HAVE_SIN_LEN
  	in.sin_len = sizeof(in);
  #endif
  	in.sin_family = AF_INET;
  	in.sin_port = htons(RIP_PORT);
  	in.sin_addr.s_addr = addr;
  	if (bind(s, (struct sockaddr *)&in, sizeof(in)) < 0) {
  		if (serious)
  			BADERR(errno != EADDRINUSE, "bind(rip_sock)");
  		return -1;
  	}
  	fix_sock(s,"rip_sock");
  
  	ttl = 1;
  	if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL,
  		       &ttl, sizeof(ttl)) < 0)
  		DBGERR(1,"rip_sock setsockopt(IP_MULTICAST_TTL)");
  
  	return s;
  }
  
  
  /* turn off main RIP socket */
  void
  rip_off(void)
  {
  	struct interface *ifp;
  	naddr addr;
  
  
  	if (rip_sock >= 0 && !mhome) {
  		trace_act("turn off RIP");
  
  		close(rip_sock);
  		rip_sock = -1;
  
  		/* get non-broadcast sockets to listen to queries.
  		 */
  		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
  			if (ifp->int_state & IS_REMOTE)
  				continue;
  			if (ifp->int_rip_sock < 0) {
  				addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
  					? ifp->int_dstaddr
  					: ifp->int_addr);
  				ifp->int_rip_sock = get_rip_sock(addr, 0);
  			}
  		}
  
  		fix_select();
  
  		age(0);
  	}
  }
  
  
  /* turn on RIP multicast input via an interface
   */
  static void
  rip_mcast_on(struct interface *ifp)
  {
  	struct ip_mreq m;
  
  	if (!IS_RIP_IN_OFF(ifp->int_state)
  	    && (ifp->int_if_flags & IFF_MULTICAST)
  #ifdef MCAST_PPP_BUG
  	    && !(ifp->int_if_flags & IFF_POINTOPOINT)
  #endif
  	    && !(ifp->int_state & IS_ALIAS)) {
  		m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
  		m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
  					  ? ifp->int_dstaddr
  					  : ifp->int_addr);
  		if (setsockopt(rip_sock,IPPROTO_IP, IP_ADD_MEMBERSHIP,
  			       &m, sizeof(m)) < 0)
  			LOGERR("setsockopt(IP_ADD_MEMBERSHIP RIP)");
  	}
  }
  
  
  /* Prepare socket used for RIP.
   */
  void
  rip_on(struct interface *ifp)
  {
  	/* If the main RIP socket is already alive, only start receiving
  	 * multicasts for this interface.
  	 */
  	if (rip_sock >= 0) {
  		if (ifp != 0)
  			rip_mcast_on(ifp);
  		return;
  	}
  
  	/* If the main RIP socket is off and it makes sense to turn it on,
  	 * then turn it on for all of the interfaces.
  	 * It makes sense if either router discovery is off, or if
  	 * router discover is on and at most one interface is doing RIP.
  	 */
  	if (rip_interfaces > 0 && (!rdisc_ok || rip_interfaces > 1)) {
  		trace_act("turn on RIP");
  
  		/* Close all of the query sockets so that we can open
  		 * the main socket.  SO_REUSEPORT is not a solution,
  		 * since that would let two daemons bind to the broadcast
  		 * socket.
  		 */
  		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
  			if (ifp->int_rip_sock >= 0) {
  				close(ifp->int_rip_sock);
  				ifp->int_rip_sock = -1;
  			}
  		}
  
  		rip_sock = get_rip_sock(INADDR_ANY, 1);
  		rip_sock_mcast = 0;
  
  		/* Do not advertise anything until we have heard something
  		 */
  		if (next_bcast.tv_sec < now.tv_sec+MIN_WAITTIME)
  			next_bcast.tv_sec = now.tv_sec+MIN_WAITTIME;
  
  		for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
  			ifp->int_query_time = NEVER;
  			rip_mcast_on(ifp);
  		}
  		ifinit_timer.tv_sec = now.tv_sec;
  
  	} else if (ifp != 0
  		   && !(ifp->int_state & IS_REMOTE)
  		   && ifp->int_rip_sock < 0) {
  		/* RIP is off, so ensure there are sockets on which
  		 * to listen for queries.
  		 */
  		ifp->int_rip_sock = get_rip_sock(ifp->int_addr, 0);
  	}
  
  	fix_select();
  }
  
  
  /* die if malloc(3) fails
   */
  void *
  rtmalloc(size_t size,
  	 const char *msg)
  {
  	void *p = malloc(size);
  	if (p == 0)
  		logbad(1,"malloc(%lu) failed in %s", (u_long)size, msg);
  	return p;
  }
  
  
  /* get a random instant in an interval
   */
  void
  intvl_random(struct timeval *tp,	/* put value here */
  	     u_long lo,			/* value is after this second */
  	     u_long hi)			/* and before this */
  {
  	tp->tv_sec = (time_t)(hi == lo
  			      ? lo
  			      : (lo + random() % ((hi - lo))));
  	tp->tv_usec = random() % 1000000;
  }
  
  
  void
  timevaladd(struct timeval *t1,
  	   struct timeval *t2)
  {
  
  	t1->tv_sec += t2->tv_sec;
  	if ((t1->tv_usec += t2->tv_usec) >= 1000000) {
  		t1->tv_sec++;
  		t1->tv_usec -= 1000000;
  	}
  }
  
  
  /* t1 = t2 - t3
   */
  static void
  timevalsub(struct timeval *t1,
  	   struct timeval *t2,
  	   struct timeval *t3)
  {
  	t1->tv_sec = t2->tv_sec - t3->tv_sec;
  	if ((t1->tv_usec = t2->tv_usec - t3->tv_usec) < 0) {
  		t1->tv_sec--;
  		t1->tv_usec += 1000000;
  	}
  }
  
  
  /* put a message into the system log
   */
  void
  msglog(const char *p, ...)
  {
  	va_list args;
  
  	trace_flush();
  
  	va_start(args, p);
  	vsyslog(LOG_ERR, p, args);
  
  	if (ftrace != 0) {
  		if (ftrace == stdout)
  			fputs("routed: ", ftrace);
  		vfprintf(ftrace, p, args);
  		fputc('\n', ftrace);
  	}
  }
  
  
  /* Put a message about a bad system into the system log if
   * we have not complained about it recently.
   *
   * It is desirable to complain about all bad systems, but not too often.
   * In the worst case, it is not practical to keep track of all bad systems.
   * For example, there can be many systems with the wrong password.
   */
  void
  msglim(struct msg_limit *lim, naddr addr, const char *p, ...)
  {
  	va_list args;
  	int i;
  	struct msg_sub *ms1, *ms;
  	const char *p1;
  
  	va_start(args, p);
  
  	/* look for the oldest slot in the table
  	 * or the slot for the bad router.
  	 */
  	ms = ms1 = lim->subs;
  	for (i = MSG_SUBJECT_N; ; i--, ms1++) {
  		if (i == 0) {
  			/* Reuse a slot at most once every 10 minutes.
  			 */
  			if (lim->reuse > now.tv_sec) {
  				ms = 0;
  			} else {
  				ms = ms1;
  				lim->reuse = now.tv_sec + 10*60;
  			}
  			break;
  		}
  		if (ms->addr == addr) {
  			/* Repeat a complaint about a given system at
  			 * most once an hour.
  			 */
  			if (ms->until > now.tv_sec)
  				ms = 0;
  			break;
  		}
  		if (ms->until < ms1->until)
  			ms = ms1;
  	}
  	if (ms != 0) {
  		ms->addr = addr;
  		ms->until = now.tv_sec + 60*60;	/* 60 minutes */
  
  		trace_flush();
  		for (p1 = p; *p1 == ' '; p1++)
  			continue;
  		vsyslog(LOG_ERR, p1, args);
  	}
  
  	/* always display the message if tracing */
  	if (ftrace != 0) {
  		vfprintf(ftrace, p, args);
  		fputc('\n', ftrace);
  	}
  }
  
  
  void
  logbad(int dump, const char *p, ...)
  {
  	va_list args;
  
  	trace_flush();
  
  	va_start(args, p);
  	vsyslog(LOG_ERR, p, args);
  
  	fputs("routed: ", stderr);
  	vfprintf(stderr, p, args);
  	fputs("; giving up\n",stderr);
  	fflush(stderr);
  
  	if (dump)
  		abort();
  	exit(1);
  }
  