Router Discovery from Sun Microsystems

4 files changed, 1813 insertions, 0 deletions

diff --git a/sbin/rdisc/DISCLAIMER b/sbin/rdisc/DISCLAIMER
new file mode 100644
index 0000000..161e84e
--- /dev/null
+++ b/sbin/rdisc/DISCLAIMER
@@ -0,0 +1,27 @@
+/*
+ * Rdisc (this program) was developed by Sun Microsystems, Inc. and is 
+ * provided for unrestricted use provided that this legend is included on 
+ * all tape media and as a part of the software program in whole or part.  
+ * Users may copy or modify Rdisc without charge, and they may freely 
+ * distribute it.
+ *
+ * RDISC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
+ * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
+ *
+ * Rdisc is provided with no support and without any obligation on the
+ * part of Sun Microsystems, Inc. to assist in its use, correction,
+ * modification or enhancement.
+ *
+ * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
+ * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY RDISC
+ * OR ANY PART THEREOF.
+ *
+ * In no event will Sun Microsystems, Inc. be liable for any lost revenue
+ * or profits or other special, indirect and consequential damages, even if
+ * Sun has been advised of the possibility of such damages.
+ *
+ * Sun Microsystems, Inc.
+ * 2550 Garcia Avenue
+ * Mountain View, California  94043
+ */
diff --git a/sbin/rdisc/rdisc.8 b/sbin/rdisc/rdisc.8
new file mode 100644
index 0000000..f6d337a
--- /dev/null
+++ b/sbin/rdisc/rdisc.8
@@ -0,0 +1,191 @@
+.\" @(#)in.rdisc.8c 1.4 91/10/21 SMI
+'\"macro stdmacro
+.\"
+.\" Rdisc (this program) was developed by Sun Microsystems, Inc. and is 
+.\" provided for unrestricted use provided that this legend is included on 
+.\" all tape media and as a part of the software program in whole or part.  
+.\" Users may copy or modify Rdisc without charge, and they may freely 
+.\" distribute it.
+.\"
+.\" RDISC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
+.\" WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
+.\"
+.\" Rdisc is provided with no support and without any obligation on the
+.\" part of Sun Microsystems, Inc. to assist in its use, correction,
+.\" modification or enhancement.
+.\"
+.\" SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
+.\" INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY RDISC
+.\" OR ANY PART THEREOF.
+.\"
+.\" In no event will Sun Microsystems, Inc. be liable for any lost revenue
+.\" or profits or other special, indirect and consequential damages, even if
+.\" Sun has been advised of the possibility of such damages.
+.\"
+.\" Sun Microsystems, Inc.
+.\" 2550 Garcia Avenue
+.\" Mountain View, California  94043
+.\"
+.nr X
+.TH in.rdisc 8C "2 Oct 1991"
+.SH NAME
+in.rdisc \- network router discovery daemon
+.SH SYNOPSIS
+.B in.rdisc
+[
+.B \-sfa
+]
+.LP
+.B in.rdisc
+.B \-r
+[
+.BI \-p " preference"
+] [
+.BI \-T " interval"
+]
+.SH DESCRIPTION
+.IX "in.rdisc" "" "\fLin.rdisc\fP \(em ICMP router discovery daemon"
+.IX "Internet" "ICMP router discovery daemon" ""  "ICMP router discovery daemon \(em \fLin.rdisc\fP"
+.IX "Internet Control Message Protocol" "See ICMP"
+.IX "ICMP" "router discovery daemon" "" "router discovery daemon \(em \fLin.rdisc\fP"  
+.LP
+\f4in.rdisc\f1
+implements the 
+.SM ICMP
+router discover protocol.
+The first form of the command is used on hosts and the
+second form is used on routers.
+On a host \f4in.rdisc\f1 is invoked at 
+boot time to populate the network routing tables with default routes. 
+On a router it is also invoked at boot time in order to start
+advertising the router to all the hosts.
+.SS "Host (First Form)"
+.PP
+On a host \f4in.rdisc\f1
+listens on the \f4ALL_HOSTS\f1 (224.0.0.1) multicast address 
+for \f4ROUTER_ADVERTISE\f1 messages from routers. The received
+messages are handled by first ignoring
+those listed router addresses with which the host does not share a network.
+Among the remaining addresses the ones with the highest preference are selected
+as default routers and a default route is entered in the kernel routing
+table for each one of them.
+.LP
+Optionally, \f4in.rdisc\f1 can avoid waiting for routers to announce 
+themselves by sending out a few \f4ROUTER_SOLICITATION\f1 messages
+to the \f4ALL_ROUTERS\f1 (224.0.0.2) multicast address when it is started.
+.LP
+A timer is associated with each router address and the address will
+no longer be considered for inclusion in the the routing tables if the 
+timer expires before a new 
+.I advertise
+message is received from the router.
+The address will also be excluded from consideration if the host receives an 
+.I advertise
+message with the preference being maximally negative.
+.SS "Router (Second Form)"
+.PP
+When 
+\f4in.rdisc\f1
+is started on a router, it uses the
+\f4SIOCGIFCONF\f1
+.BR ioctl (2)
+to find the interfaces configured into the system and it starts
+listening on the \f4ALL_ROUTERS\f1 multicast address on all the interfaces
+that support multicast.
+It sends out
+.I advertise
+messages to the \f4ALL_HOSTS\f1 multicast address advertising all its
+.BM IP
+addresses.
+A few initial 
+.I advertise
+messages are sent out during the first 30 seconds and after that it will
+transmit 
+.I advertise
+messages approximately every 600 seconds.
+.LP
+When \f4in.rdisc\f1
+receives a 
+.I solicitation
+message it sends an 
+.I advertise 
+message to the host that sent the 
+.I solicitation
+message.
+.LP
+When
+.B in.rdisc
+is terminated by a signal it sends out an
+.I advertise
+message with the preference being maximally negative.
+.br
+.ne 1i
+.SH OPTIONS
+.TP 15
+.B \-a
+Accept all routers independently of the preference they have in their 
+.I advertise
+messages.
+Normally
+.B in.rdisc
+only accepts (and enters in the kernel routing tables) 
+the router or routers with the highest preference.
+.TP
+.B \-f
+Run
+.B in.rdisc 
+forever even if no routers are found.
+Normally 
+.B in.rdisc 
+gives up if it has not received any 
+.I advertise 
+message after after soliciting three times,
+in which case it exits with a non-zero exit code.
+If 
+.B \-f 
+is not specified in the first form then 
+.B \-s
+must be specified.
+.TP
+.BI \-p " preference"
+Set the preference transmitted in the 
+.I solicitation
+messages.
+The default is zero.
+.TP
+.B \-r
+Act as a router as opposed to a host.
+.TP
+.B \-s
+Send three 
+.I solicitation
+messages initially to quickly discover the routers
+when the system is booted.
+When 
+.B \-s
+is specified 
+.B in.rdisc
+exits with a non-zero exit code if it can not find any routers.
+This can be overridden with the
+.B \-f
+option.
+.TP
+.BI \-T " interval"
+Set the interval between transmitting the
+.I advertise
+messages.
+The default time is 600 seconds.
+.SH "SEE ALSO"
+.BR in.routed (8C)
+.BR ioctl (2),
+.BR icmp (7),
+.BR inet (7)
+.LP
+Deering, S.E.,ed
+.RI `` "ICMP Router Discovery Messages" ,''
+.SM RFC
+1256, Network Information Center,
+.SM SRI
+International, Menlo Park, Calif.,
+September 1991.
diff --git a/sbin/rdisc/rdisc.c b/sbin/rdisc/rdisc.c
new file mode 100644
index 0000000..b9c674c
--- /dev/null
+++ b/sbin/rdisc/rdisc.c
@@ -0,0 +1,1576 @@
+/*
+ * Rdisc (this program) was developed by Sun Microsystems, Inc. and is 
+ * provided for unrestricted use provided that this legend is included on 
+ * all tape media and as a part of the software program in whole or part.  
+ * Users may copy or modify Rdisc without charge, and they may freely 
+ * distribute it.
+ *
+ * RDISC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
+ * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
+ *
+ * Rdisc is provided with no support and without any obligation on the
+ * part of Sun Microsystems, Inc. to assist in its use, correction,
+ * modification or enhancement.
+ *
+ * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
+ * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY RDISC
+ * OR ANY PART THEREOF.
+ *
+ * In no event will Sun Microsystems, Inc. be liable for any lost revenue
+ * or profits or other special, indirect and consequential damages, even if
+ * Sun has been advised of the possibility of such damages.
+ *
+ * Sun Microsystems, Inc.
+ * 2550 Garcia Avenue
+ * Mountain View, California  94043
+ */
+#include <stdio.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+#include <sys/param.h>
+#include <sys/socket.h>
+#include <sys/file.h>
+
+#include <sys/ioctl.h>
+#include <net/if.h>
+
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
+
+/*
+ * The next include contains all defs and structures for multicast
+ * that are not in SunOS 4.1.x. On a SunOS 4.1.x system none of this code
+ * is ever used because it does not support multicast
+ * Fraser Gardiner - Sun Microsystems Australia
+ */
+
+#include "rdisc.h"
+#include <netdb.h>
+#include <arpa/inet.h>
+
+#include <string.h>
+#include <syslog.h>
+
+/* 
+ * TBD
+ *	Use 255.255.255.255 for broadcasts - not the interface broadcast
+ *	address.
+ */
+
+char *malloc();
+void exit();
+long gethostid();
+long random();
+time_t time();
+long strtol();
+
+#ifdef lint
+#define ALLIGN(ptr)	(ptr ? 0 : 0)
+#else
+#define ALLIGN(ptr)	(ptr)
+#endif
+
+#ifdef SYSV
+#define signal(s,f)	sigset(s,f)
+#define random()	rand()
+#endif
+
+void solicitor(), advertise(), pr_pack(), init();
+void bzero(), initlog(), logerr(), logtrace(), logdebug(), logperror();
+void age_table(), record_router(), add_route(), del_route(), rtioctl();
+int support_multicast(), sendbcast(), sendmcast(), sendbcastif(), sendmcastif();
+int ismulticast(), isbroadcast(), in_cksum(), is_directly_connected();
+static int join();
+
+#define ICMP_ROUTER_ADVERTISEMENT	9
+#define ICMP_ROUTER_SOLICITATION	10
+
+#define ALL_HOSTS_ADDRESS		"224.0.0.1"
+#define ALL_ROUTERS_ADDRESS		"224.0.0.2"
+
+#define MAXIFS 32
+
+/* For router advertisement */
+struct icmp_ra {
+	u_char	icmp_type;		/* type of message, see below */
+	u_char	icmp_code;		/* type sub code */
+	u_short	icmp_cksum;		/* ones complement cksum of struct */
+	u_char	icmp_num_addrs;
+	u_char	icmp_wpa;		/* Words per address */
+	short 	icmp_lifetime;
+};
+
+struct icmp_ra_addr {
+	u_long	addr;
+	u_long preference;
+};
+
+/* Router constants */
+#define	MAX_INITIAL_ADVERT_INTERVAL	16
+#define	MAX_INITIAL_ADVERTISEMENTS  	3
+#define	MAX_RESPONSE_DELAY		2	/* Not used */
+
+/* Host constants */
+#define MAX_SOLICITATIONS 		3
+#define SOLICITATION_INTERVAL 		3
+#define MAX_SOLICITATION_DELAY		1	/* Not used */
+
+#define IGNORE_PREFERENCE	0x80000000	/* Maximum negative */
+
+#define MAX_ADV_INT 600
+
+/* Statics */
+int num_interfaces;
+struct interface {
+	struct in_addr 	address;	/* Used to identify the interface */
+	struct in_addr	localaddr;	/* Actual address if the interface */
+	int 		preference;
+	int		flags;
+	struct in_addr	bcastaddr;
+	struct in_addr	remoteaddr;
+	struct in_addr	netmask;
+};
+struct interface *interfaces;
+int interfaces_size;			/* Number of elements in interfaces */
+
+
+#define	MAXPACKET	4096	/* max packet size */
+u_char	packet[MAXPACKET];
+
+/* fraser */
+int debugfile;
+char usage[] =
+"Usage:	rdisc [-s] [-v] [-f] [-a] [send_address] [receive_address]\n\
+        rdisc -r [-v] [-p <preference>] [-T <secs>] \n\
+		[send_address] [receive_address]\n";
+
+
+int s;			/* Socket file descriptor */
+struct sockaddr_in whereto;/* Address to send to */
+
+/* Common variables */
+int verbose = 0;
+int debug = 0;
+int trace = 0;
+int solicit = 0;
+int responder;
+int ntransmitted = 0;
+int nreceived = 0;
+int forever = 0;	/* Never give up on host. If 0 defer fork until 
+			 * first response.
+			 */
+
+/* Router variables */
+int max_adv_int = MAX_ADV_INT;
+int min_adv_int;
+int lifetime;
+int initial_advert_interval = MAX_INITIAL_ADVERT_INTERVAL;
+int initial_advertisements = MAX_INITIAL_ADVERTISEMENTS;
+int preference = 0;		/* Setable with -p option */
+
+/* Host variables */
+int max_solicitations = MAX_SOLICITATIONS;
+unsigned int solicitation_interval = SOLICITATION_INTERVAL;
+int best_preference = 1;  	/* Set to record only the router(s) with the 
+				   best preference in the kernel. Not set
+				   puts all routes in the kernel. */
+
+
+void finish(), catcher(), timer(), initifs();
+char *pr_name();
+
+static void prusage()
+{
+	(void) fprintf(stderr, usage);
+	exit(1);
+}
+
+void
+do_fork()
+{
+	int t;
+	long pid;
+	
+	if (trace)
+		return;
+
+	if (pid =fork())
+		exit(0);
+
+	for (t = 0; t < 20; t++)
+		if (t != s)
+			(void) close(t);
+
+#ifndef SYSV
+	t = open("/dev/tty", 2);
+	if (t >= 0) {
+		(void) ioctl(t, TIOCNOTTY, (char *)0);
+		(void) close(t);
+	}
+#else
+	(void) setpgrp ();
+#endif
+	initlog();
+}
+
+/*
+ * 			M A I N
+ */
+char    *sendaddress, *recvaddress;
+
+main(argc, argv)
+char *argv[];
+{
+#ifndef SYSV
+	struct sigvec sv;
+#endif
+	struct sockaddr_in from;
+	char **av = argv;
+	struct sockaddr_in *to = &whereto;
+	struct sockaddr_in joinaddr;
+	int val;
+
+	min_adv_int =( max_adv_int * 3 / 4);
+	lifetime = (3*max_adv_int);
+
+	argc--, av++;
+	while (argc > 0 && *av[0] == '-') {
+		while (*++av[0]) switch (*av[0]) {
+		case 'd':
+			debug = 1;
+			break;
+		case 't':
+			trace = 1;
+			break;
+		case 'v':
+			verbose++;
+			break;
+		case 's':
+			solicit = 1;
+			break;
+		case 'r':
+			responder = 1;
+			break;
+		case 'a':
+			best_preference = 0;
+			break;
+		case 'b':
+			best_preference = 1;
+			break;
+		case 'f':
+			forever = 1;
+			break;
+		case 'T':
+			argc--, av++;
+			if (argc != 0) {
+				val = strtol(av[0], (char **)NULL, 0);
+				if (val < 4 || val > 1800) {
+					(void) fprintf(stderr, 
+				          "Bad Max Advertizement Interval\n");
+					exit(1);
+				}
+				max_adv_int = val;
+				min_adv_int =( max_adv_int * 3 / 4);
+				lifetime = (3*max_adv_int);
+			} else {
+				prusage();
+				/* NOTREACHED*/
+			} 
+			goto next;
+		case 'p':
+			argc--, av++;
+			if (argc != 0) {
+				val = strtol(av[0], (char **)NULL, 0);
+				preference = val;
+			} else {
+				prusage();
+				/* NOTREACHED*/
+			}
+			goto next;
+		default:
+			prusage();
+			/* NOTREACHED*/
+		}
+	next:
+		argc--, av++;
+	}
+	if( argc < 1)  {
+		if (support_multicast()) {
+			if (responder)
+				sendaddress = ALL_HOSTS_ADDRESS;
+			else
+				sendaddress = ALL_ROUTERS_ADDRESS;
+		} else
+			sendaddress = "255.255.255.255";
+	} else {
+		sendaddress = av[0];
+		argc--;
+	}
+
+	if (argc < 1) {
+		if (support_multicast()) {
+			if (responder)
+				recvaddress = ALL_ROUTERS_ADDRESS;
+			else
+				recvaddress = ALL_HOSTS_ADDRESS;
+		} else
+			recvaddress = "255.255.255.255";
+	} else {
+		recvaddress = av[0];
+		argc--;
+	}
+	if (argc != 0) {
+		(void) fprintf(stderr, "Extra paramaters\n");
+		prusage();
+		/* NOTREACHED */
+	}
+
+	if (solicit && responder) {
+		prusage();
+		/* NOTREACHED */
+	}
+
+	if (!(solicit && !forever)) {
+		do_fork();
+/*
+ * Added the next line to stop forking a second time
+ * Fraser Gardiner - Sun Microsystems Australia
+ */
+		forever = 1;
+	}
+
+	bzero( (char *)&whereto, sizeof(struct sockaddr_in) );
+	to->sin_family = AF_INET;
+	to->sin_addr.s_addr = inet_addr(sendaddress);
+
+	bzero( (char *)&joinaddr, sizeof(struct sockaddr_in) );
+	joinaddr.sin_family = AF_INET;
+	joinaddr.sin_addr.s_addr = inet_addr(recvaddress);
+
+	if (responder) {
+#ifdef SYSV
+		/* TBD fix this to be more random */
+		srand((u_int)time((time_t *)NULL));
+#else
+		srandom((int)gethostid());
+#endif
+	}
+
+	if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0) {
+		logperror("socket");
+		exit(5);
+	}
+
+#ifdef SYSV
+	setvbuf( stdout, NULL, _IOLBF, 0 );
+#else
+	setlinebuf( stdout );
+#endif
+
+	(void) signal( SIGINT, finish );
+	(void) signal( SIGTERM, finish );
+	(void) signal( SIGHUP, initifs );
+
+	init();
+	if (join(s, &joinaddr) < 0) {
+		logerr("Failed joining addresses\n");
+		exit (2);
+	}
+
+
+#ifdef SYSV
+	(void) sigset(SIGALRM, timer);
+#else
+	/*
+	 * Make sure that this signal actually interrupts (rather than
+	 * restarts) the recvfrom call below.
+	 */
+	sv.sv_handler = timer;
+	sv.sv_mask = 0;
+	sv.sv_flags = SV_INTERRUPT;
+	(void) sigvec(SIGALRM, &sv, (struct sigvec *)NULL);
+#endif
+	timer();	/* start things going */
+
+	for (;;) {
+		int len = sizeof (packet);
+		int fromlen = sizeof (from);
+		int cc;
+
+		if ( (cc=recvfrom(s, (char *)packet, len, 0, 
+				  (struct sockaddr *)&from, &fromlen)) < 0) {
+			if( errno == EINTR )
+				continue;
+			logperror("recvfrom");
+			continue;
+		}
+		pr_pack( (char *)packet, cc, &from );
+	}
+	/*NOTREACHED*/
+}
+
+#define TIMER_INTERVAL 	3
+#define GETIFCONF_TIMER	30
+
+static left_until_advertise;
+
+/* Called every TIMER_INTERVAL */
+void timer()
+{
+	static time;
+	static left_until_getifconf;
+	static left_until_solicit;
+
+
+	time += TIMER_INTERVAL;
+
+	left_until_getifconf -= TIMER_INTERVAL;
+	left_until_advertise -= TIMER_INTERVAL;
+	left_until_solicit -= TIMER_INTERVAL;
+
+	if (left_until_getifconf < 0) {
+		initifs();
+		left_until_getifconf = GETIFCONF_TIMER;
+	}
+	if (responder && left_until_advertise <= 0) {
+		ntransmitted++;
+		advertise(&whereto);
+		if (ntransmitted < initial_advertisements)
+			left_until_advertise = initial_advert_interval;
+		else
+			left_until_advertise = min_adv_int + 
+				((max_adv_int - min_adv_int) * 
+				 (random() % 1000)/1000);
+	} else if (solicit && left_until_solicit <= 0) {
+		ntransmitted++;
+		solicitor(&whereto);
+		if (ntransmitted < max_solicitations)
+			left_until_solicit = solicitation_interval;
+		else {
+			solicit = 0;
+			if (!forever && nreceived == 0)
+				exit(5);
+		}
+	}
+	age_table(TIMER_INTERVAL);
+	(void) alarm(TIMER_INTERVAL);
+}
+
+/*
+ * 			S O L I C I T O R
+ * 
+ * Compose and transmit an ICMP ROUTER SOLICITATION REQUEST packet.  
+ * The IP packet will be added on by the kernel.  
+ */
+void
+solicitor(sin)
+	struct sockaddr_in *sin;
+{
+	static u_char outpack[MAXPACKET];
+	register struct icmp *icp = (struct icmp *) ALLIGN(outpack);
+	int packetlen, i;
+	
+	if (verbose) {
+		logtrace("Sending solicitation to %s\n",
+			 pr_name(sin->sin_addr));
+	}
+	icp->icmp_type = ICMP_ROUTER_SOLICITATION;
+	icp->icmp_code = 0;
+	icp->icmp_cksum = 0;
+	icp->icmp_void = 0; /* Reserved */
+	packetlen = 8;
+
+	/* Compute ICMP checksum here */
+	icp->icmp_cksum = in_cksum( (u_short *)icp, packetlen );
+
+	if (isbroadcast(sin)) 
+		i = sendbcast(s, (char *)outpack, packetlen);
+	else if (ismulticast(sin))
+		i = sendmcast( s, (char *)outpack, packetlen, sin);
+	else
+		i = sendto( s, (char *)outpack, packetlen, 0,
+			   (struct sockaddr *)sin, sizeof(struct sockaddr));
+
+	if( i < 0 || i != packetlen )  {
+		if( i<0 ) {
+		    logperror("sendto");
+		}
+		logerr("wrote %s %d chars, ret=%d\n",
+			sendaddress, packetlen, i );
+	}
+}
+
+/*
+ * 			A V E R T I S E
+ * 
+ * Compose and transmit an ICMP ROUTER ADVERTISEMENT packet.  
+ * The IP packet will be added on by the kernel.  
+ */
+void
+advertise(sin)
+	struct sockaddr_in *sin;
+{
+	static u_char outpack[MAXPACKET];
+	register struct icmp_ra *rap = (struct icmp_ra *) ALLIGN(outpack);
+	struct icmp_ra_addr *ap;
+	int packetlen, i, cc;
+	
+	if (verbose) {
+		logtrace("Sending advertisement to %s\n",
+			 pr_name(sin->sin_addr));
+	}
+	
+	for (i = 0; i < num_interfaces; i++) {
+		rap->icmp_type = ICMP_ROUTER_ADVERTISEMENT;
+		rap->icmp_code = 0;
+		rap->icmp_cksum = 0;
+		rap->icmp_num_addrs = 0; 
+		rap->icmp_wpa = 2;
+		rap->icmp_lifetime = lifetime;
+		packetlen = 8;
+
+		/* 
+		 * TODO handle multiple logical interfaces per 
+		 * physical interface. (increment with rap->icmp_wpa * 4 for
+		 * each address.)
+		 */
+		ap = (struct icmp_ra_addr *)ALLIGN(outpack + ICMP_MINLEN);
+		ap->addr = interfaces[i].localaddr.s_addr;
+		ap->preference = interfaces[i].preference;
+		packetlen += rap->icmp_wpa * 4;
+		rap->icmp_num_addrs++;
+
+
+		/* Compute ICMP checksum here */
+		rap->icmp_cksum = in_cksum( (u_short *)rap, packetlen );
+
+		if (isbroadcast(sin)) 
+			cc = sendbcastif(s, (char *)outpack, packetlen, 
+					&interfaces[i]);
+		else if (ismulticast(sin))
+			cc = sendmcastif( s, (char *)outpack, packetlen, sin,
+					&interfaces[i]);
+		else {
+			struct interface *ifp = &interfaces[i];
+			/* 
+			 * Verify that the interface matches the destination
+			 * address.
+			 */
+			if ((sin->sin_addr.s_addr & ifp->netmask.s_addr) ==
+			    (ifp->address.s_addr & ifp->netmask.s_addr)) {
+				if (debug) {
+					logdebug("Unicast to %s ",
+						 pr_name(sin->sin_addr));
+					logdebug("on interface %s\n",	
+						 pr_name(ifp->address));
+				}
+				cc = sendto( s, (char *)outpack, packetlen, 0,
+					    (struct sockaddr *)sin, 
+					    sizeof(struct sockaddr));
+			} else
+				cc = packetlen;
+		}
+		if( cc < 0 || cc != packetlen )  {
+			if (cc < 0) {
+				logperror("sendto");
+			} else {
+				logerr("wrote %s %d chars, ret=%d\n",
+				       sendaddress, packetlen, cc );
+			}
+		}
+	}
+}
+
+/*
+ * 			P R _ T Y P E
+ *
+ * Convert an ICMP "type" field to a printable string.
+ */
+char *
+pr_type( t )
+register int t;
+{
+	static char *ttab[] = {
+		"Echo Reply",
+		"ICMP 1",
+		"ICMP 2",
+		"Dest Unreachable",
+		"Source Quench",
+		"Redirect",
+		"ICMP 6",
+		"ICMP 7",
+		"Echo",
+		"Router Advertise",
+		"Router Solicitation",
+		"Time Exceeded",
+		"Parameter Problem",
+		"Timestamp",
+		"Timestamp Reply",
+		"Info Request",
+		"Info Reply",
+		"Netmask Request",
+		"Netmask Reply"
+	};
+
+	if ( t < 0 || t > 16 )
+		return("OUT-OF-RANGE");
+
+	return(ttab[t]);
+}
+
+/*
+ *			P R _ N A M E
+ *
+ * Return a string name for the given IP address.
+ */
+char *pr_name(addr)
+    struct in_addr addr;
+{
+	char *inet_ntoa();
+	struct hostent *phe;
+	static char buf[256];
+
+	phe = gethostbyaddr((char *)&addr.s_addr, 4, AF_INET);
+	if (phe == NULL) 
+		return( inet_ntoa(addr));
+	(void) sprintf(buf, "%s (%s)", phe->h_name, inet_ntoa(addr));
+	return(buf);
+}
+
+/*
+ *			P R _ P A C K
+ *
+ * Print out the packet, if it came from us.  This logic is necessary
+ * because ALL readers of the ICMP socket get a copy of ALL ICMP packets
+ * which arrive ('tis only fair).  This permits multiple copies of this
+ * program to be run without having intermingled output (or statistics!).
+ */
+void
+pr_pack( buf, cc, from )
+char *buf;
+int cc;
+struct sockaddr_in *from;
+{
+	struct ip *ip;
+	register struct icmp *icp;
+	register int i;
+	int hlen;
+
+	ip = (struct ip *) ALLIGN(buf);
+	hlen = ip->ip_hl << 2;
+	if (cc < hlen + ICMP_MINLEN) {
+		if (verbose)
+			logtrace("packet too short (%d bytes) from %s\n", cc,
+				 pr_name(from->sin_addr));
+		return;
+	}
+	cc -= hlen;
+	icp = (struct icmp *)ALLIGN(buf + hlen);
+	if (ip->ip_p == 0) {
+		/*
+		 * Assume that we are running on a pre-4.3BSD system
+		 * such as SunOS before 4.0
+		 */
+		 icp = (struct icmp *)ALLIGN(buf);
+	}
+	switch (icp->icmp_type) {
+	case ICMP_ROUTER_ADVERTISEMENT: {
+		struct icmp_ra *rap = (struct icmp_ra *)ALLIGN(icp);
+		struct icmp_ra_addr *ap;
+
+		if (responder)
+			break;
+
+		/* TBD verify that the link is multicast or broadcast */
+		/* XXX Find out the link it came in over? */
+#ifdef notdef
+		if (debug) {
+			logdebug("ROUTER_ADVERTISEMENT: \n");
+			pr_hex(buf+hlen, cc);
+		}
+#endif notdef
+		if (in_cksum((u_short *)ALLIGN(buf+hlen), cc)) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Bad checksum\n",
+					 pr_type((int)rap->icmp_type),
+					 pr_name(from->sin_addr));
+			return;
+		}
+		if (rap->icmp_code != 0) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Code = %d\n",
+					 pr_type((int)rap->icmp_type),
+					 pr_name(from->sin_addr),
+					 rap->icmp_code);
+			return;
+		}
+		if (rap->icmp_num_addrs < 1) {
+			if (verbose) 
+				logtrace("ICMP %s from %s: No addresses\n",
+					 pr_type((int)rap->icmp_type),
+					 pr_name(from->sin_addr));
+			return;
+		}
+		if (rap->icmp_wpa < 2) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Words/addr = %d\n",
+					 pr_type((int)rap->icmp_type),
+					 pr_name(from->sin_addr),
+					 rap->icmp_wpa);
+			return;
+		}
+		if ((unsigned)cc < 
+		    ICMP_MINLEN + rap->icmp_num_addrs * rap->icmp_wpa * 4) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Too short %d, %d\n",
+					      pr_type((int)rap->icmp_type),
+					      pr_name(from->sin_addr),
+					      cc, 
+					      ICMP_MINLEN + 
+					      rap->icmp_num_addrs * rap->icmp_wpa * 4);
+			return;
+		}
+		if (rap->icmp_lifetime < 4) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Lifetime = %d\n",
+					      pr_type((int)rap->icmp_type),
+					      pr_name(from->sin_addr),
+					      rap->icmp_lifetime);
+			return;
+		}
+		if (verbose)
+			logtrace("ICMP %s from %s, lifetime %d\n",
+				      pr_type((int)rap->icmp_type),
+				      pr_name(from->sin_addr),
+				      rap->icmp_lifetime);
+
+		/* Check that at least one router address is a neighboor
+		 * on the arriving link.
+		 */
+		for (i = 0; (unsigned)i < rap->icmp_num_addrs; i++) {
+			struct in_addr ina;
+			ap = (struct icmp_ra_addr *)
+				ALLIGN(buf + hlen + ICMP_MINLEN + 
+				       i * rap->icmp_wpa * 4);
+			ina.s_addr = ntohl(ap->addr);
+			if (verbose)
+				logtrace("\taddress %s, preference 0x%x\n", 
+					      pr_name(ina),
+					      ntohl(ap->preference));
+			if (!responder) {
+				if (is_directly_connected(ina))
+					record_router(ina, 
+						      (long)ntohl(ap->preference),
+						      rap->icmp_lifetime);
+			}
+		}
+		nreceived++;
+		if (!forever) {
+			do_fork();
+			forever = 1;
+/*
+ * The next line was added so that the alarm is set for the new procces
+ * Fraser Gardiner Sun Microsystems Australia
+ */
+			(void) alarm(TIMER_INTERVAL);
+		}
+		break;
+	}
+		
+	case ICMP_ROUTER_SOLICITATION: {
+		struct sockaddr_in sin;
+
+		if (!responder)
+			break;
+
+		/* TBD verify that the link is multicast or broadcast */
+		/* XXX Find out the link it came in over? */
+#ifdef notdef
+		if (debug) {
+			logdebug("ROUTER_SOLICITATION: \n");
+			pr_hex(buf+hlen, cc);
+		}
+#endif notdef
+		if (in_cksum((u_short *)ALLIGN(buf+hlen), cc)) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Bad checksum\n",
+					      pr_type((int)icp->icmp_type),
+					      pr_name(from->sin_addr));
+			return;
+		}
+		if (icp->icmp_code != 0) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Code = %d\n",
+					      pr_type((int)icp->icmp_type),
+					      pr_name(from->sin_addr),
+					      icp->icmp_code);
+			return;
+		}
+
+		if (cc < ICMP_MINLEN) {
+			if (verbose)
+				logtrace("ICMP %s from %s: Too short %d, %d\n",
+					      pr_type((int)icp->icmp_type),
+					      pr_name(from->sin_addr),
+					      cc, 
+					      ICMP_MINLEN);
+			return;
+		}
+
+		if (verbose)
+			logtrace("ICMP %s from %s\n",
+				      pr_type((int)icp->icmp_type),
+				      pr_name(from->sin_addr));
+		
+ 		if (!responder) 
+			break;
+
+		/* Check that ip_src is either a neighboor
+		 * on the arriving link or 0.
+		 */
+		sin.sin_family = AF_INET;
+		if (ip->ip_src.s_addr == 0) {
+			/* If it was sent to the broadcast address we respond
+			 * to the broadcast address.
+			 */
+			if (IN_CLASSD(ip->ip_dst.s_addr))
+				sin.sin_addr.s_addr = INADDR_ALLHOSTS_GROUP;
+			else
+				sin.sin_addr.s_addr = INADDR_BROADCAST;
+			/* Restart the timer when we broadcast */
+			left_until_advertise = min_adv_int + 
+				((max_adv_int - min_adv_int) 
+				 * (random() % 1000)/1000);
+		}
+		else {
+			if (!is_directly_connected(ip->ip_src)) {
+				if (verbose)
+					logtrace("ICMP %s from %s: source not directly connected\n",
+						      pr_type((int)icp->icmp_type),
+						      pr_name(from->sin_addr));
+				break;
+			}
+			sin.sin_addr.s_addr = ip->ip_src.s_addr;
+		}
+		nreceived++;
+		ntransmitted++;
+		advertise(&sin);
+		break;
+	}
+	}
+}
+
+
+/*
+ *			I N _ C K S U M
+ *
+ * Checksum routine for Internet Protocol family headers (C Version)
+ *
+ */
+in_cksum(addr, len)
+u_short *addr;
+int len;
+{
+	register int nleft = len;
+	register u_short *w = addr;
+	register u_short answer;
+	u_short odd_byte = 0;
+	register int sum = 0;
+
+	/*
+	 *  Our algorithm is simple, using a 32 bit accumulator (sum),
+	 *  we add sequential 16 bit words to it, and at the end, fold
+	 *  back all the carry bits from the top 16 bits into the lower
+	 *  16 bits.
+	 */
+	while( nleft > 1 )  {
+		sum += *w++;
+		nleft -= 2;
+	}
+
+	/* mop up an odd byte, if necessary */
+	if( nleft == 1 ) {
+		*(u_char *)(&odd_byte) = *(u_char *)w;
+		sum += odd_byte;
+	}
+
+	/*
+	 * add back carry outs from top 16 bits to low 16 bits
+	 */
+	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
+	sum += (sum >> 16);			/* add carry */
+	answer = ~sum;				/* truncate to 16 bits */
+	return (answer);
+}
+
+/*
+ *			F I N I S H
+ *
+ * Print out statistics, and give up.
+ * Heavily buffered STDIO is used here, so that all the statistics
+ * will be written with 1 sys-write call.  This is nice when more
+ * than one copy of the program is running on a terminal;  it prevents
+ * the statistics output from becomming intermingled.
+ */
+void
+finish()
+{
+	if (responder) {
+		int i;
+
+		/* Send out a packet with a preference so that all
+		 * hosts will know that we are dead.
+		 */
+		logerr("terminated\n");
+		for (i = 0; i < num_interfaces; i++)
+			interfaces[i].preference = IGNORE_PREFERENCE;
+		ntransmitted++;
+		advertise(&whereto);
+	}		
+	logtrace("\n----%s rdisc Statistics----\n", sendaddress );
+	logtrace("%d packets transmitted, ", ntransmitted );
+	logtrace("%d packets received, ", nreceived );
+	logtrace("\n");
+	(void) fflush(stdout);
+	exit(0);
+}
+
+#include <ctype.h>
+
+#ifdef notdef
+pr_hex(data, len)
+int len;
+unsigned char *data;
+{
+	FILE *out;
+
+	out = stdout;
+
+	while (len) {
+		register int i;
+		char charstring[17];
+			
+		(void)strcpy(charstring,"                "); /* 16 spaces */
+		for (i = 0; i < 16; i++) {
+			/* output the bytes one at a time, 
+			 * not going pas "len" bytes 
+			 */
+			if (len) {
+				char ch = *data & 0x7f; /* strip parity */
+				if (!isprint((u_char)ch)) 
+					ch = ' '; /* ensure printable */
+				charstring[i] = ch;
+				(void) fprintf(out,"%02x ",*data++);
+				len--;
+			} else 
+				(void) fprintf(out,"   ");
+			if (i==7) 
+				(void) fprintf(out,"   ");
+		}
+		
+		(void) fprintf(out,"    *%s*\n",charstring);
+	}
+}
+#endif notdef
+
+isbroadcast(sin)
+	struct sockaddr_in *sin;
+{
+	return (sin->sin_addr.s_addr == INADDR_BROADCAST);
+}
+
+ismulticast(sin)
+	struct sockaddr_in *sin;
+{
+	return (IN_CLASSD(sin->sin_addr.s_addr));
+}
+
+/* From libc/rpc/pmap_rmt.c */
+
+int
+sendbcast(s, packet, packetlen)
+	int s;
+	char *packet;
+	int packetlen;
+{
+	int i, cc;
+	
+	for (i = 0; i < num_interfaces; i++) {
+		if ((interfaces[i].flags & IFF_BROADCAST) == 0)
+			continue;
+		cc = sendbcastif(s, packet, packetlen, &interfaces[i]);
+		if (cc!= packetlen) {
+			return (cc);
+		}
+	}
+	return (packetlen);
+}
+
+int
+sendbcastif(s, packet, packetlen, ifp)
+	int s;
+	char *packet;
+	int packetlen;
+	struct interface *ifp;
+{
+	int cc;
+	struct sockaddr_in baddr;
+
+	baddr.sin_family = AF_INET;
+	
+	if ((ifp->flags & IFF_BROADCAST) == 0)
+		return (packetlen);
+
+	baddr.sin_addr = ifp->bcastaddr;
+	if (debug)
+		logdebug("Broadcast to %s\n",
+			 pr_name(baddr.sin_addr));
+	cc = sendto(s, packet, packetlen, 0,
+		    (struct sockaddr *)&baddr, sizeof (struct sockaddr));
+	if (cc!= packetlen) {
+		logperror("sendbcast: sendto");
+		logerr("Cannot send broadcast packet to %s\n",
+		       pr_name(baddr.sin_addr));
+	}
+	return (cc);
+}
+
+int
+sendmcast(s, packet, packetlen, sin)
+	int s;
+	char *packet;
+	int packetlen;
+	struct sockaddr_in *sin;
+{
+	int i, cc;
+	
+	for (i = 0; i < num_interfaces; i++) {
+		if ((interfaces[i].flags & IFF_MULTICAST) == 0)
+			continue;
+		cc = sendmcastif(s, packet, packetlen, sin, &interfaces[i]);
+		if (cc!= packetlen) {
+			return (cc);
+		}
+	}
+	return (packetlen);
+}	
+
+int
+sendmcastif(s, packet, packetlen, sin, ifp)
+	int s;
+	char *packet;
+	int packetlen;
+	struct sockaddr_in *sin;
+	struct interface *ifp;
+{
+	int cc;
+	struct sockaddr_in ifaddr;
+
+	ifaddr.sin_family = AF_INET;
+	
+	if ((ifp->flags & IFF_MULTICAST) == 0)
+		return (packetlen);
+
+	ifaddr.sin_addr = ifp->address;
+	if (debug)
+		logdebug("Multicast to interface %s\n",
+			 pr_name(ifaddr.sin_addr));
+	if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, 
+		       (char *)&ifaddr.sin_addr,
+		       sizeof(ifaddr.sin_addr)) < 0) {
+		logperror("setsockopt (IP_MULTICAST_IF)");
+		logerr("Cannot send multicast packet over interface %s\n",
+		       pr_name(ifaddr.sin_addr));
+		return (-1);
+	}
+	cc = sendto(s, packet, packetlen, 0,
+		    (struct sockaddr *)sin, sizeof (struct sockaddr));
+	if (cc!= packetlen) {
+		logperror("sendmcast: sendto");
+		logerr("Cannot send multicast packet over interface %s\n",
+		       pr_name(ifaddr.sin_addr));
+	}
+	return (cc);
+}
+
+void
+init()
+{
+	int i;
+
+	initifs();
+	for (i = 0; i < interfaces_size; i++)
+		interfaces[i].preference = preference;
+}
+
+void
+initifs()
+{
+	int	sock;
+	struct ifconf ifc;
+	struct ifreq ifreq, *ifr;
+	struct sockaddr_in *sin;
+	int n, i;
+	char *buf;
+	int numifs;
+	unsigned bufsize;
+
+	sock = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sock < 0) {
+		logperror("initifs: socket");
+		return;
+	}
+#ifdef SIOCGIFNUM
+	if (ioctl(sock, SIOCGIFNUM, (char *)&numifs) < 0) {
+		numifs = MAXIFS;
+	}
+#else
+	numifs = MAXIFS;
+#endif
+	bufsize = numifs * sizeof(struct ifreq);
+	buf = (char *)malloc(bufsize);
+	if (buf == NULL) {
+		logerr("out of memory\n");
+		(void) close(sock);
+		return;
+	}
+	if (interfaces) 
+		interfaces = (struct interface *)ALLIGN(realloc((char *)interfaces,
+					 numifs * sizeof(struct interface)));
+	else
+		interfaces = (struct interface *)ALLIGN(malloc(numifs *
+						sizeof(struct interface)));
+	if (interfaces == NULL) {
+		logerr("out of memory\n");
+		(void) close(sock);
+		(void) free(buf);
+		return;
+	}
+	interfaces_size = numifs;
+						
+	ifc.ifc_len = bufsize;
+	ifc.ifc_buf = buf;
+	if (ioctl(sock, SIOCGIFCONF, (char *)&ifc) < 0) {
+		logperror("initifs: ioctl (get interface configuration)");
+		(void) close(sock);
+		(void) free(buf);
+		return;
+	}
+	ifr = ifc.ifc_req;
+	for (i = 0, n = ifc.ifc_len/sizeof (struct ifreq); n > 0; n--, ifr++) {
+		ifreq = *ifr;
+		if (ioctl(sock, SIOCGIFFLAGS, (char *)&ifreq) < 0) {
+			logperror("initifs: ioctl (get interface flags)");
+			continue;
+		}
+		if (ifr->ifr_addr.sa_family != AF_INET) 
+			continue;
+		if ((ifreq.ifr_flags & IFF_UP) == 0)
+			continue;
+		if (ifreq.ifr_flags & IFF_LOOPBACK)
+			continue;
+		if ((ifreq.ifr_flags & (IFF_MULTICAST | IFF_BROADCAST)) == 0)
+			continue;
+		sin = (struct sockaddr_in *)ALLIGN(&ifr->ifr_addr);
+		interfaces[i].localaddr = sin->sin_addr;
+		interfaces[i].flags = ifreq.ifr_flags;
+		interfaces[i].netmask.s_addr = (unsigned long)0xffffffff;
+		if (ifreq.ifr_flags & IFF_POINTOPOINT) {
+			if (ioctl(sock, SIOCGIFDSTADDR, (char *)&ifreq) < 0) {
+				logperror("initifs: ioctl (get destination addr)");
+				continue;
+			}
+			sin = (struct sockaddr_in *)ALLIGN(&ifreq.ifr_addr);
+			/* A pt-pt link is identified by the remote address */
+			interfaces[i].address = sin->sin_addr;
+			interfaces[i].remoteaddr = sin->sin_addr;
+			/* Simulate broadcast for pt-pt */
+			interfaces[i].bcastaddr = sin->sin_addr;
+			interfaces[i].flags |= IFF_BROADCAST;
+		} else {
+			/* Non pt-pt links are identified by the local address */
+			interfaces[i].address = interfaces[i].localaddr;
+			interfaces[i].remoteaddr = interfaces[i].address;
+			if (ioctl(sock, SIOCGIFNETMASK, (char *)&ifreq) < 0) {
+				logperror("initifs: ioctl (get netmask)");
+				continue;
+			}
+			sin = (struct sockaddr_in *)ALLIGN(&ifreq.ifr_addr);
+			interfaces[i].netmask = sin->sin_addr;
+			if (ifreq.ifr_flags & IFF_BROADCAST) {
+				if (ioctl(sock, SIOCGIFBRDADDR, (char *)&ifreq) < 0) {
+					logperror("initifs: ioctl (get broadcast address)");
+					continue;
+				}
+				sin = (struct sockaddr_in *)ALLIGN(&ifreq.ifr_addr);
+				interfaces[i].bcastaddr = sin->sin_addr;
+			}
+		}
+#ifdef notdef
+		if (debug)
+			logdebug("Found interface %s, flags 0x%x\n",
+				 pr_name(interfaces[i].localaddr),
+				 interfaces[i].flags);
+#endif
+		i++;
+	}
+	num_interfaces = i;
+#ifdef notdef
+	if (debug)
+		logdebug("Found %d interfaces\n", num_interfaces);
+#endif
+	(void) close(sock);
+	(void) free(buf);
+}
+
+static int 
+join(sock, sin)
+	int sock;
+	struct sockaddr_in *sin;
+{
+	int i;
+	struct ip_mreq mreq;
+
+	if (isbroadcast(sin))
+		return (0);
+
+	mreq.imr_multiaddr = sin->sin_addr;
+	for (i = 0; i < num_interfaces; i++) {
+		mreq.imr_interface = interfaces[i].address;
+
+		if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+			       (char *)&mreq, sizeof(mreq)) < 0) {
+			logperror("setsockopt (IP_ADD_MEMBERSHIP)");
+			return (-1);
+		}
+	}
+	return (0);
+}
+
+int support_multicast()
+{
+	int sock;
+	u_char ttl = 1;
+
+	sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (sock < 0) {
+		logperror("support_multicast: socket");
+		return (0);
+	}
+
+	if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, 
+		       (char *)&ttl, sizeof(ttl)) < 0) {
+		(void) close(sock);
+		return (0);
+	}
+	(void) close(sock);
+	return (1);
+}
+
+int
+is_directly_connected(in)
+	struct in_addr in;
+{
+	int i;
+
+	for (i = 0; i < num_interfaces; i++) {
+		/* Check that the subnetwork numbers match */
+
+		if ((in.s_addr & interfaces[i].netmask.s_addr ) == 
+		    (interfaces[i].remoteaddr.s_addr & interfaces[i].netmask.s_addr))
+			return (1);
+	}
+	return (0);
+}
+
+
+/*
+ * TABLES
+ */
+struct table {
+	struct in_addr	router;
+	int		preference;
+	int		remaining_time;
+	int		in_kernel;
+	struct table	*next;
+};
+
+struct table *table;
+
+struct table *
+find_router(addr)
+	struct in_addr addr;
+{
+	struct table *tp;
+
+	tp = table;
+	while (tp) {
+		if (tp->router.s_addr == addr.s_addr)
+			return (tp);
+		tp = tp->next;
+	}
+	return (NULL);
+}
+
+int max_preference()
+{
+	struct table *tp;
+	int max = (int)IGNORE_PREFERENCE;
+
+	tp = table;
+	while (tp) {
+		if (tp->preference > max)
+			max = tp->preference;
+		tp = tp->next;
+	}
+	return (max);
+}
+
+
+/* Note: this might leave the kernel with no default route for a short time. */
+void
+age_table(time)
+	int time;
+{
+	struct table **tpp, *tp;
+	int recalculate_max = 0;
+	int max = max_preference();
+
+	tpp = &table; 
+	while (*tpp != NULL) {
+		tp = *tpp;
+		tp->remaining_time -= time;
+		if (tp->remaining_time <= 0) {
+			*tpp = tp->next;
+			if (tp->in_kernel) 
+				del_route(tp->router);
+			if (best_preference && 
+			    tp->preference == max)
+				recalculate_max++;
+			free((char *)tp);
+		} else {
+			tpp = &tp->next;
+		}
+	}
+	if (recalculate_max) {
+		int max = max_preference();
+
+		if (max != IGNORE_PREFERENCE) {
+			tp = table;
+			while (tp) {
+				if (tp->preference == max && !tp->in_kernel) {
+					add_route(tp->router);
+					tp->in_kernel++;
+				}
+				tp = tp->next;
+			}
+		}
+	}
+}
+
+void
+record_router(router, preference, ttl)
+	struct in_addr 	router;
+	long		preference;
+	int		ttl;
+{
+	struct table *tp;
+	int old_max = max_preference();
+	int changed_up = 0;	/* max preference could have increased */
+	int changed_down = 0;	/* max preference could have decreased */
+	
+	if (debug)
+		logdebug("Recording %s, preference 0x%x\n", 
+			      pr_name(router),
+			      preference);
+	tp = find_router(router);
+	if (tp) {
+		if (tp->preference > preference &&
+		    tp->preference == old_max)
+			changed_down++;
+		else if (preference > tp->preference)
+			changed_up++;
+		tp->preference = preference;
+		tp->remaining_time = ttl;
+	} else {
+		if (preference > old_max)
+			changed_up++;
+		tp = (struct table *)ALLIGN(malloc(sizeof(struct table)));
+		if (tp == NULL) {
+			logerr("Out of memory\n");
+			return;
+		}
+		tp->router = router;
+		tp->preference = preference;
+		tp->remaining_time = ttl;
+		tp->in_kernel = 0;
+		tp->next = table;
+		table = tp;
+	}
+	if (!tp->in_kernel && 
+	    (!best_preference || tp->preference == max_preference()) &&
+	    tp->preference != IGNORE_PREFERENCE) {
+		add_route(tp->router);
+		tp->in_kernel++;
+	}
+	if (tp->preference == IGNORE_PREFERENCE && tp->in_kernel) {
+		del_route(tp->router);
+		tp->in_kernel = 0;
+	}
+	if (best_preference && changed_down) {
+		/* Check if we should add routes */
+		int new_max = max_preference();
+		if (new_max != IGNORE_PREFERENCE) {
+			tp = table;
+			while (tp) {
+				if (tp->preference == new_max && 
+				    !tp->in_kernel) {
+					add_route(tp->router);
+					tp->in_kernel++;
+				}
+				tp = tp->next;
+			}
+		}
+	}
+	if (best_preference && (changed_up || changed_down)) {
+		/* Check if we should remove routes already in the kernel */
+		int new_max = max_preference();
+		tp = table;
+		while (tp) {
+			if (tp->preference < new_max && tp->in_kernel) {
+				del_route(tp->router);
+				tp->in_kernel = 0;
+			}
+			tp = tp->next;
+		}
+	}
+}
+
+	
+#include <net/route.h>
+
+void
+add_route(addr)
+	struct in_addr addr;
+{
+	if (debug)
+		logdebug("Add default route to %s\n", pr_name(addr));
+	rtioctl(addr, SIOCADDRT);
+}
+
+void
+del_route(addr)
+	struct in_addr addr;
+{
+	if (debug)
+		logdebug("Delete default route to %s\n", pr_name(addr));
+	rtioctl(addr, SIOCDELRT);
+}
+
+void
+rtioctl(addr, op)
+	struct in_addr addr;
+	int	op;
+{
+	int sock;
+	struct rtentry rt;
+	struct sockaddr_in *sin;
+	bzero((char *)&rt, sizeof(struct rtentry));
+	rt.rt_dst.sa_family = AF_INET;
+	rt.rt_gateway.sa_family = AF_INET;
+	sin = (struct sockaddr_in *)ALLIGN(&rt.rt_gateway);
+	sin->sin_addr = addr;
+	rt.rt_flags = RTF_UP | RTF_GATEWAY;
+	
+	sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (sock < 0) {
+		logperror("rtioctl: socket");
+		return;
+	}
+	if (ioctl(sock, op, (char *)&rt) < 0) {
+		if (!(op == SIOCADDRT && errno == EEXIST))
+			logperror("ioctl (add/delete route)");
+	}
+	(void) close(sock);
+}
+
+
+	
+/*
+ * LOGGER
+ */
+
+
+static logging = 0;
+
+void
+initlog()
+{
+	logging++;
+	openlog("in.rdiscd", LOG_PID | LOG_CONS, LOG_DAEMON);
+}
+
+/* VARARGS1 */
+void
+logerr(fmt, a,b,c,d,e,f,g,h)
+	char *fmt;
+{
+	if (logging)
+		syslog(LOG_ERR, fmt, a,b,c,d,e,f,g,h);
+	else
+		(void) fprintf(stderr, fmt, a,b,c,d,e,f,g,h);
+}
+
+/* VARARGS1 */
+void
+logtrace(fmt, a,b,c,d,e,f,g,h)
+	char *fmt;
+{
+	if (logging)
+		syslog(LOG_INFO, fmt, a,b,c,d,e,f,g,h);
+	else
+		(void) fprintf(stdout, fmt, a,b,c,d,e,f,g,h);
+}
+
+/* VARARGS1 */
+void
+logdebug(fmt, a,b,c,d,e,f,g,h)
+	char *fmt;
+{
+	if (logging)
+		syslog(LOG_DEBUG, fmt, a,b,c,d,e,f,g,h);
+	else
+		(void) fprintf(stdout, fmt, a,b,c,d,e,f,g,h);
+}
+
+extern char *sys_errlist[];
+extern int errno;
+
+void
+logperror(str)
+	char *str;
+{
+	if (logging)
+		syslog(LOG_ERR, "%s: %s\n", str, sys_errlist[errno]);
+	else
+		(void) fprintf(stderr, "%s: %s\n", str, sys_errlist[errno]);
+}
+
+
+#ifdef SYSV
+void
+bzero(cp, len)
+	char *cp;
+	int len;
+{
+	while (--len>=0)
+		*cp++ = 0;
+}
+#endif
+
diff --git a/sbin/rdisc/rdisc.h b/sbin/rdisc/rdisc.h
new file mode 100644
index 0000000..8a3d845
--- /dev/null
+++ b/sbin/rdisc/rdisc.h
@@ -0,0 +1,19 @@
+/* From net/if.h */
+
+#define IFF_MULTICAST   0x800           /* supports multicast */
+
+/* From netinet/in.h */
+
+#define INADDR_ALLHOSTS_GROUP   (u_long)0xe0000001      /* 224.0.0.1   */
+#define IP_MULTICAST_IF         0x10    /* set/get IP multicast interface  */
+#define IP_ADD_MEMBERSHIP       0x13    /* add  an IP group membership     */
+#define IP_MULTICAST_TTL        0x11    /* set/get IP multicast timetolive */
+
+/*
+ * Argument structure for IP_ADD_MEMBERSHIP and IP_DROP_MEMBERSHIP.
+ */
+struct ip_mreq {
+        struct in_addr  imr_multiaddr;  /* IP multicast address of group */
+        struct in_addr  imr_interface;  /* local IP address of interface */
+};
+