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rdisc.c revision 1.6
      1  1.6     lukem /*	$NetBSD: rdisc.c,v 1.6 1997/09/15 10:38:19 lukem Exp $	*/
      2  1.2   thorpej 
      3  1.1   thorpej /*
      4  1.1   thorpej  * Copyright (c) 1995
      5  1.1   thorpej  *	The Regents of the University of California.  All rights reserved.
      6  1.1   thorpej  *
      7  1.1   thorpej  * Redistribution and use in source and binary forms, with or without
      8  1.1   thorpej  * modification, are permitted provided that the following conditions
      9  1.1   thorpej  * are met:
     10  1.1   thorpej  * 1. Redistributions of source code must retain the above copyright
     11  1.1   thorpej  *    notice, this list of conditions and the following disclaimer.
     12  1.1   thorpej  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.1   thorpej  *    notice, this list of conditions and the following disclaimer in the
     14  1.1   thorpej  *    documentation and/or other materials provided with the distribution.
     15  1.1   thorpej  * 3. All advertising materials mentioning features or use of this software
     16  1.1   thorpej  *    must display the following acknowledgement:
     17  1.1   thorpej  *	This product includes software developed by the University of
     18  1.1   thorpej  *	California, Berkeley and its contributors.
     19  1.1   thorpej  * 4. Neither the name of the University nor the names of its contributors
     20  1.1   thorpej  *    may be used to endorse or promote products derived from this software
     21  1.1   thorpej  *    without specific prior written permission.
     22  1.1   thorpej  *
     23  1.1   thorpej  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  1.1   thorpej  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  1.1   thorpej  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  1.1   thorpej  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  1.1   thorpej  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  1.1   thorpej  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  1.1   thorpej  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  1.1   thorpej  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  1.1   thorpej  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  1.1   thorpej  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  1.1   thorpej  * SUCH DAMAGE.
     34  1.1   thorpej  */
     35  1.1   thorpej 
     36  1.4  christos #if !defined(lint) && !defined(sgi) && !defined(__NetBSD__)
     37  1.1   thorpej static char sccsid[] = "@(#)rdisc.c	8.1 (Berkeley) x/y/95";
     38  1.4  christos #elif defined(__NetBSD__)
     39  1.6     lukem #include <sys/cdefs.h>
     40  1.6     lukem __RCSID("$NetBSD: rdisc.c,v 1.6 1997/09/15 10:38:19 lukem Exp $");
     41  1.2   thorpej #endif
     42  1.1   thorpej 
     43  1.1   thorpej #include "defs.h"
     44  1.1   thorpej #include <netinet/in_systm.h>
     45  1.1   thorpej #include <netinet/ip.h>
     46  1.1   thorpej #include <netinet/ip_icmp.h>
     47  1.1   thorpej 
     48  1.1   thorpej /* router advertisement ICMP packet */
     49  1.1   thorpej struct icmp_ad {
     50  1.4  christos 	u_int8_t    icmp_type;		/* type of message */
     51  1.4  christos 	u_int8_t    icmp_code;		/* type sub code */
     52  1.4  christos 	u_int16_t   icmp_cksum;		/* ones complement cksum of struct */
     53  1.4  christos 	u_int8_t    icmp_ad_num;	/* # of following router addresses */
     54  1.4  christos 	u_int8_t    icmp_ad_asize;	/* 2--words in each advertisement */
     55  1.4  christos 	u_int16_t   icmp_ad_life;	/* seconds of validity */
     56  1.1   thorpej 	struct icmp_ad_info {
     57  1.1   thorpej 	    n_long  icmp_ad_addr;
     58  1.1   thorpej 	    n_long  icmp_ad_pref;
     59  1.1   thorpej 	} icmp_ad_info[1];
     60  1.1   thorpej };
     61  1.1   thorpej 
     62  1.1   thorpej /* router solicitation ICMP packet */
     63  1.1   thorpej struct icmp_so {
     64  1.4  christos 	u_int8_t    icmp_type;		/* type of message */
     65  1.4  christos 	u_int8_t    icmp_code;		/* type sub code */
     66  1.4  christos 	u_int16_t   icmp_cksum;		/* ones complement cksum of struct */
     67  1.4  christos 	n_long	    icmp_so_rsvd;
     68  1.1   thorpej };
     69  1.1   thorpej 
     70  1.1   thorpej union ad_u {
     71  1.1   thorpej 	struct icmp icmp;
     72  1.1   thorpej 	struct icmp_ad ad;
     73  1.1   thorpej 	struct icmp_so so;
     74  1.1   thorpej };
     75  1.1   thorpej 
     76  1.1   thorpej 
     77  1.1   thorpej int	rdisc_sock = -1;		/* router-discovery raw socket */
     78  1.1   thorpej struct interface *rdisc_sock_mcast;	/* current multicast interface */
     79  1.1   thorpej 
     80  1.1   thorpej struct timeval rdisc_timer;
     81  1.1   thorpej int rdisc_ok;				/* using solicited route */
     82  1.1   thorpej 
     83  1.1   thorpej 
     84  1.1   thorpej #define MAX_ADS 5
     85  1.1   thorpej struct dr {				/* accumulated advertisements */
     86  1.1   thorpej     struct interface *dr_ifp;
     87  1.1   thorpej     naddr   dr_gate;			/* gateway */
     88  1.1   thorpej     time_t  dr_ts;			/* when received */
     89  1.1   thorpej     time_t  dr_life;			/* lifetime */
     90  1.1   thorpej     n_long  dr_recv_pref;		/* received but biased preference */
     91  1.1   thorpej     n_long  dr_pref;			/* preference adjusted by metric */
     92  1.1   thorpej } *cur_drp, drs[MAX_ADS];
     93  1.1   thorpej 
     94  1.1   thorpej /* adjust preference by interface metric without driving it to infinity */
     95  1.1   thorpej #define PREF(p, ifp) ((p) <= (ifp)->int_metric ? ((p) != 0 ? 1 : 0) \
     96  1.1   thorpej 		      : (p) - ((ifp)->int_metric))
     97  1.1   thorpej 
     98  1.1   thorpej static void rdisc_sort(void);
     99  1.1   thorpej 
    100  1.1   thorpej 
    101  1.1   thorpej /* dump an ICMP Router Discovery Advertisement Message
    102  1.1   thorpej  */
    103  1.1   thorpej static void
    104  1.1   thorpej trace_rdisc(char	*act,
    105  1.1   thorpej 	    naddr	from,
    106  1.1   thorpej 	    naddr	to,
    107  1.1   thorpej 	    struct interface *ifp,
    108  1.1   thorpej 	    union ad_u	*p,
    109  1.1   thorpej 	    u_int	len)
    110  1.1   thorpej {
    111  1.1   thorpej 	int i;
    112  1.1   thorpej 	n_long *wp, *lim;
    113  1.1   thorpej 
    114  1.1   thorpej 
    115  1.1   thorpej 	if (!TRACEPACKETS || ftrace == 0)
    116  1.1   thorpej 		return;
    117  1.1   thorpej 
    118  1.1   thorpej 	lastlog();
    119  1.1   thorpej 
    120  1.1   thorpej 	if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
    121  1.1   thorpej 		(void)fprintf(ftrace, "%s Router Ad"
    122  1.1   thorpej 			      " from %s to %s via %s life=%d\n",
    123  1.1   thorpej 			      act, naddr_ntoa(from), naddr_ntoa(to),
    124  1.1   thorpej 			      ifp ? ifp->int_name : "?",
    125  1.1   thorpej 			      ntohs(p->ad.icmp_ad_life));
    126  1.1   thorpej 		if (!TRACECONTENTS)
    127  1.1   thorpej 			return;
    128  1.1   thorpej 
    129  1.1   thorpej 		wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
    130  1.1   thorpej 		lim = &wp[(len - sizeof(p->ad)) / sizeof(*wp)];
    131  1.1   thorpej 		for (i = 0; i < p->ad.icmp_ad_num && wp <= lim; i++) {
    132  1.5  christos 			(void)fprintf(ftrace, "\t%s preference=%d",
    133  1.4  christos 				      naddr_ntoa(wp[0]), (int)ntohl(wp[1]));
    134  1.1   thorpej 			wp += p->ad.icmp_ad_asize;
    135  1.1   thorpej 		}
    136  1.1   thorpej 		(void)fputc('\n',ftrace);
    137  1.1   thorpej 
    138  1.1   thorpej 	} else {
    139  1.5  christos 		trace_act("%s Router Solic. from %s to %s via %s value=%#x",
    140  1.1   thorpej 			  act, naddr_ntoa(from), naddr_ntoa(to),
    141  1.1   thorpej 			  ifp ? ifp->int_name : "?",
    142  1.1   thorpej 			  ntohl(p->so.icmp_so_rsvd));
    143  1.1   thorpej 	}
    144  1.1   thorpej }
    145  1.1   thorpej 
    146  1.4  christos /* prepare Router Discovery socket.
    147  1.4  christos  */
    148  1.4  christos static void
    149  1.4  christos get_rdisc_sock(void)
    150  1.4  christos {
    151  1.4  christos 	if (rdisc_sock < 0) {
    152  1.4  christos 		rdisc_sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
    153  1.4  christos 		if (rdisc_sock < 0)
    154  1.4  christos 			BADERR(1,"rdisc_sock = socket()");
    155  1.4  christos 		fix_sock(rdisc_sock,"rdisc_sock");
    156  1.4  christos 		fix_select();
    157  1.4  christos 	}
    158  1.4  christos }
    159  1.4  christos 
    160  1.1   thorpej 
    161  1.1   thorpej /* Pick multicast group for router-discovery socket
    162  1.1   thorpej  */
    163  1.1   thorpej void
    164  1.1   thorpej set_rdisc_mg(struct interface *ifp,
    165  1.5  christos 	     int on)			/* 0=turn it off */
    166  1.5  christos {
    167  1.1   thorpej 	struct ip_mreq m;
    168  1.1   thorpej 
    169  1.4  christos 	if (rdisc_sock < 0) {
    170  1.4  christos 		/* Create the raw socket so that we can hear at least
    171  1.4  christos 		 * broadcast router discovery packets.
    172  1.4  christos 		 */
    173  1.4  christos 		if ((ifp->int_state & IS_NO_RDISC) == IS_NO_RDISC
    174  1.4  christos 		    || !on)
    175  1.4  christos 			return;
    176  1.4  christos 		get_rdisc_sock();
    177  1.4  christos 	}
    178  1.4  christos 
    179  1.5  christos 	if (!(ifp->int_if_flags & IFF_MULTICAST)) {
    180  1.1   thorpej 		ifp->int_state &= ~(IS_ALL_HOSTS | IS_ALL_ROUTERS);
    181  1.1   thorpej 		return;
    182  1.1   thorpej 	}
    183  1.1   thorpej 
    184  1.1   thorpej #ifdef MCAST_PPP_BUG
    185  1.1   thorpej 	if (ifp->int_if_flags & IFF_POINTOPOINT)
    186  1.1   thorpej 		return;
    187  1.1   thorpej #endif
    188  1.6     lukem 	memset(&m, 0, sizeof(m));
    189  1.1   thorpej 	m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
    190  1.1   thorpej 				  ? ifp->int_dstaddr
    191  1.1   thorpej 				  : ifp->int_addr);
    192  1.1   thorpej 	if (supplier
    193  1.1   thorpej 	    || (ifp->int_state & IS_NO_ADV_IN)
    194  1.1   thorpej 	    || !on) {
    195  1.4  christos 		/* stop listening to advertisements
    196  1.4  christos 		 */
    197  1.1   thorpej 		if (ifp->int_state & IS_ALL_HOSTS) {
    198  1.1   thorpej 			m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
    199  1.1   thorpej 			if (setsockopt(rdisc_sock, IPPROTO_IP,
    200  1.1   thorpej 				       IP_DROP_MEMBERSHIP,
    201  1.1   thorpej 				       &m, sizeof(m)) < 0)
    202  1.1   thorpej 				LOGERR("IP_DROP_MEMBERSHIP ALLHOSTS");
    203  1.1   thorpej 			ifp->int_state &= ~IS_ALL_HOSTS;
    204  1.1   thorpej 		}
    205  1.1   thorpej 
    206  1.1   thorpej 	} else if (!(ifp->int_state & IS_ALL_HOSTS)) {
    207  1.4  christos 		/* start listening to advertisements
    208  1.4  christos 		 */
    209  1.1   thorpej 		m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
    210  1.1   thorpej 		if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
    211  1.1   thorpej 			       &m, sizeof(m)) < 0) {
    212  1.1   thorpej 			LOGERR("IP_ADD_MEMBERSHIP ALLHOSTS");
    213  1.1   thorpej 		} else {
    214  1.1   thorpej 			ifp->int_state |= IS_ALL_HOSTS;
    215  1.1   thorpej 		}
    216  1.1   thorpej 	}
    217  1.1   thorpej 
    218  1.1   thorpej 	if (!supplier
    219  1.1   thorpej 	    || (ifp->int_state & IS_NO_ADV_OUT)
    220  1.1   thorpej 	    || !on) {
    221  1.4  christos 		/* stop listening to solicitations
    222  1.4  christos 		 */
    223  1.1   thorpej 		if (ifp->int_state & IS_ALL_ROUTERS) {
    224  1.1   thorpej 			m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
    225  1.1   thorpej 			if (setsockopt(rdisc_sock, IPPROTO_IP,
    226  1.1   thorpej 				       IP_DROP_MEMBERSHIP,
    227  1.1   thorpej 				       &m, sizeof(m)) < 0)
    228  1.1   thorpej 				LOGERR("IP_DROP_MEMBERSHIP ALLROUTERS");
    229  1.1   thorpej 			ifp->int_state &= ~IS_ALL_ROUTERS;
    230  1.1   thorpej 		}
    231  1.1   thorpej 
    232  1.1   thorpej 	} else if (!(ifp->int_state & IS_ALL_ROUTERS)) {
    233  1.4  christos 		/* start hearing solicitations
    234  1.4  christos 		 */
    235  1.1   thorpej 		m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
    236  1.1   thorpej 		if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
    237  1.1   thorpej 			       &m, sizeof(m)) < 0) {
    238  1.1   thorpej 			LOGERR("IP_ADD_MEMBERSHIP ALLROUTERS");
    239  1.1   thorpej 		} else {
    240  1.1   thorpej 			ifp->int_state |= IS_ALL_ROUTERS;
    241  1.1   thorpej 		}
    242  1.1   thorpej 	}
    243  1.1   thorpej }
    244  1.1   thorpej 
    245  1.1   thorpej 
    246  1.1   thorpej /* start supplying routes
    247  1.1   thorpej  */
    248  1.1   thorpej void
    249  1.1   thorpej set_supplier(void)
    250  1.1   thorpej {
    251  1.1   thorpej 	struct interface *ifp;
    252  1.1   thorpej 	struct dr *drp;
    253  1.1   thorpej 
    254  1.1   thorpej 	if (supplier_set)
    255  1.1   thorpej 		return;
    256  1.1   thorpej 
    257  1.5  christos 	trace_act("start suppying routes");
    258  1.1   thorpej 
    259  1.1   thorpej 	/* Forget discovered routes.
    260  1.1   thorpej 	 */
    261  1.1   thorpej 	for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
    262  1.1   thorpej 		drp->dr_recv_pref = 0;
    263  1.1   thorpej 		drp->dr_life = 0;
    264  1.1   thorpej 	}
    265  1.1   thorpej 	rdisc_age(0);
    266  1.1   thorpej 
    267  1.1   thorpej 	supplier_set = 1;
    268  1.1   thorpej 	supplier = 1;
    269  1.1   thorpej 
    270  1.1   thorpej 	/* Do not start advertising until we have heard some RIP routes */
    271  1.1   thorpej 	LIM_SEC(rdisc_timer, now.tv_sec+MIN_WAITTIME);
    272  1.1   thorpej 
    273  1.1   thorpej 	/* Switch router discovery multicast groups from soliciting
    274  1.1   thorpej 	 * to advertising.
    275  1.1   thorpej 	 */
    276  1.1   thorpej 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
    277  1.1   thorpej 		if (ifp->int_state & IS_BROKE)
    278  1.1   thorpej 			continue;
    279  1.1   thorpej 		ifp->int_rdisc_cnt = 0;
    280  1.1   thorpej 		ifp->int_rdisc_timer.tv_usec = rdisc_timer.tv_usec;
    281  1.1   thorpej 		ifp->int_rdisc_timer.tv_sec = now.tv_sec+MIN_WAITTIME;
    282  1.1   thorpej 		set_rdisc_mg(ifp, 1);
    283  1.1   thorpej 	}
    284  1.1   thorpej 
    285  1.1   thorpej 	/* get rid of any redirects */
    286  1.1   thorpej 	del_redirects(0,0);
    287  1.1   thorpej }
    288  1.1   thorpej 
    289  1.1   thorpej 
    290  1.1   thorpej /* age discovered routes and find the best one
    291  1.1   thorpej  */
    292  1.1   thorpej void
    293  1.1   thorpej rdisc_age(naddr bad_gate)
    294  1.1   thorpej {
    295  1.1   thorpej 	time_t sec;
    296  1.1   thorpej 	struct dr *drp;
    297  1.1   thorpej 
    298  1.1   thorpej 
    299  1.1   thorpej 	/* If only adverising, then do only that. */
    300  1.1   thorpej 	if (supplier) {
    301  1.1   thorpej 		/* if switching from client to server, get rid of old
    302  1.1   thorpej 		 * default routes.
    303  1.1   thorpej 		 */
    304  1.1   thorpej 		if (cur_drp != 0)
    305  1.1   thorpej 			rdisc_sort();
    306  1.1   thorpej 		rdisc_adv();
    307  1.1   thorpej 		return;
    308  1.1   thorpej 	}
    309  1.1   thorpej 
    310  1.1   thorpej 	/* If we are being told about a bad router,
    311  1.1   thorpej 	 * then age the discovered default route, and if there is
    312  1.1   thorpej 	 * no alternative, solicite a replacement.
    313  1.1   thorpej 	 */
    314  1.1   thorpej 	if (bad_gate != 0) {
    315  1.1   thorpej 		/* Look for the bad discovered default route.
    316  1.1   thorpej 		 * Age it and note its interface.
    317  1.1   thorpej 		 */
    318  1.1   thorpej 		for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
    319  1.1   thorpej 			if (drp->dr_ts == 0)
    320  1.1   thorpej 				continue;
    321  1.1   thorpej 
    322  1.1   thorpej 			/* When we find the bad router, then age the route
    323  1.1   thorpej 			 * to at most SUPPLY_INTERVAL.
    324  1.1   thorpej 			 * This is contrary to RFC 1256, but defends against
    325  1.1   thorpej 			 * black holes.
    326  1.1   thorpej 			 */
    327  1.1   thorpej 			if (drp->dr_gate == bad_gate) {
    328  1.1   thorpej 				sec = (now.tv_sec - drp->dr_life
    329  1.1   thorpej 				       + SUPPLY_INTERVAL);
    330  1.1   thorpej 				if (drp->dr_ts > sec) {
    331  1.5  christos 					trace_act("age 0.0.0.0 --> %s via %s",
    332  1.1   thorpej 						  naddr_ntoa(drp->dr_gate),
    333  1.1   thorpej 						  drp->dr_ifp->int_name);
    334  1.1   thorpej 					drp->dr_ts = sec;
    335  1.1   thorpej 				}
    336  1.1   thorpej 				break;
    337  1.1   thorpej 			}
    338  1.1   thorpej 		}
    339  1.1   thorpej 	}
    340  1.1   thorpej 
    341  1.1   thorpej 	/* delete old redirected routes to keep the kernel table small
    342  1.1   thorpej 	 */
    343  1.1   thorpej 	sec = (cur_drp == 0) ? MaxMaxAdvertiseInterval : cur_drp->dr_life;
    344  1.1   thorpej 	del_redirects(bad_gate, now.tv_sec-sec);
    345  1.1   thorpej 
    346  1.1   thorpej 	rdisc_sol();
    347  1.1   thorpej 
    348  1.1   thorpej 	rdisc_sort();
    349  1.1   thorpej }
    350  1.1   thorpej 
    351  1.1   thorpej 
    352  1.1   thorpej /* Zap all routes discovered via an interface that has gone bad
    353  1.1   thorpej  *	This should only be called when !(ifp->int_state & IS_ALIAS)
    354  1.1   thorpej  */
    355  1.1   thorpej void
    356  1.1   thorpej if_bad_rdisc(struct interface *ifp)
    357  1.1   thorpej {
    358  1.1   thorpej 	struct dr *drp;
    359  1.1   thorpej 
    360  1.1   thorpej 	for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
    361  1.1   thorpej 		if (drp->dr_ifp != ifp)
    362  1.1   thorpej 			continue;
    363  1.1   thorpej 		drp->dr_recv_pref = 0;
    364  1.1   thorpej 		drp->dr_life = 0;
    365  1.1   thorpej 	}
    366  1.1   thorpej 
    367  1.1   thorpej 	rdisc_sort();
    368  1.1   thorpej }
    369  1.1   thorpej 
    370  1.1   thorpej 
    371  1.1   thorpej /* mark an interface ok for router discovering.
    372  1.1   thorpej  */
    373  1.1   thorpej void
    374  1.1   thorpej if_ok_rdisc(struct interface *ifp)
    375  1.1   thorpej {
    376  1.1   thorpej 	set_rdisc_mg(ifp, 1);
    377  1.1   thorpej 
    378  1.1   thorpej 	ifp->int_rdisc_cnt = 0;
    379  1.1   thorpej 	ifp->int_rdisc_timer.tv_sec = now.tv_sec + (supplier
    380  1.1   thorpej 						    ? MIN_WAITTIME
    381  1.1   thorpej 						    : MAX_SOLICITATION_DELAY);
    382  1.1   thorpej 	if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
    383  1.1   thorpej 		rdisc_timer = ifp->int_rdisc_timer;
    384  1.1   thorpej }
    385  1.1   thorpej 
    386  1.1   thorpej 
    387  1.1   thorpej /* get rid of a dead discovered router
    388  1.1   thorpej  */
    389  1.1   thorpej static void
    390  1.1   thorpej del_rdisc(struct dr *drp)
    391  1.1   thorpej {
    392  1.1   thorpej 	struct interface *ifp;
    393  1.1   thorpej 	int i;
    394  1.1   thorpej 
    395  1.1   thorpej 
    396  1.1   thorpej 	del_redirects(drp->dr_gate, 0);
    397  1.1   thorpej 	drp->dr_ts = 0;
    398  1.1   thorpej 	drp->dr_life = 0;
    399  1.1   thorpej 
    400  1.1   thorpej 
    401  1.1   thorpej 	/* Count the other discovered routes on the interface.
    402  1.1   thorpej 	 */
    403  1.1   thorpej 	i = 0;
    404  1.1   thorpej 	ifp = drp->dr_ifp;
    405  1.1   thorpej 	for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
    406  1.1   thorpej 		if (drp->dr_ts != 0
    407  1.1   thorpej 		    && drp->dr_ifp == ifp)
    408  1.1   thorpej 			i++;
    409  1.1   thorpej 	}
    410  1.1   thorpej 
    411  1.1   thorpej 	/* If that was the last good discovered router on the interface,
    412  1.1   thorpej 	 * then solicit a new one.
    413  1.1   thorpej 	 * This is contrary to RFC 1256, but defends against black holes.
    414  1.1   thorpej 	 */
    415  1.1   thorpej 	if (i == 0
    416  1.1   thorpej 	    && ifp->int_rdisc_cnt >= MAX_SOLICITATIONS) {
    417  1.5  christos 		trace_act("discovered route is bad--re-solicit routers via %s",
    418  1.5  christos 			  ifp->int_name);
    419  1.1   thorpej 		ifp->int_rdisc_cnt = 0;
    420  1.1   thorpej 		ifp->int_rdisc_timer.tv_sec = 0;
    421  1.1   thorpej 		rdisc_sol();
    422  1.1   thorpej 	}
    423  1.1   thorpej }
    424  1.1   thorpej 
    425  1.1   thorpej 
    426  1.1   thorpej /* Find the best discovered route,
    427  1.1   thorpej  * and discard stale routers.
    428  1.1   thorpej  */
    429  1.1   thorpej static void
    430  1.1   thorpej rdisc_sort(void)
    431  1.1   thorpej {
    432  1.1   thorpej 	struct dr *drp, *new_drp;
    433  1.1   thorpej 	struct rt_entry *rt;
    434  1.1   thorpej 	struct interface *ifp;
    435  1.1   thorpej 	u_int new_st;
    436  1.1   thorpej 	n_long new_pref;
    437  1.1   thorpej 
    438  1.1   thorpej 
    439  1.1   thorpej 	/* Find the best discovered route.
    440  1.1   thorpej 	 */
    441  1.1   thorpej 	new_drp = 0;
    442  1.6     lukem 	new_st = 0;
    443  1.6     lukem 	new_pref = 0;
    444  1.1   thorpej 	for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
    445  1.1   thorpej 		if (drp->dr_ts == 0)
    446  1.1   thorpej 			continue;
    447  1.1   thorpej 		ifp = drp->dr_ifp;
    448  1.1   thorpej 
    449  1.1   thorpej 		/* Get rid of expired discovered routers.
    450  1.1   thorpej 		 */
    451  1.1   thorpej 		if (drp->dr_ts + drp->dr_life <= now.tv_sec) {
    452  1.1   thorpej 			del_rdisc(drp);
    453  1.1   thorpej 			continue;
    454  1.1   thorpej 		}
    455  1.1   thorpej 
    456  1.1   thorpej 		LIM_SEC(rdisc_timer, drp->dr_ts+drp->dr_life+1);
    457  1.1   thorpej 
    458  1.1   thorpej 		/* Update preference with possibly changed interface
    459  1.1   thorpej 		 * metric.
    460  1.1   thorpej 		 */
    461  1.1   thorpej 		drp->dr_pref = PREF(drp->dr_recv_pref, ifp);
    462  1.1   thorpej 
    463  1.1   thorpej 		/* Prefer the current route to prevent thrashing.
    464  1.1   thorpej 		 * Prefer shorter lifetimes to speed the detection of
    465  1.1   thorpej 		 * bad routers.
    466  1.1   thorpej 		 * Avoid sick interfaces.
    467  1.1   thorpej 		 */
    468  1.1   thorpej 		if (new_drp == 0
    469  1.1   thorpej 		    || (!((new_st ^ drp->dr_ifp->int_state) & IS_SICK)
    470  1.1   thorpej 			&& (new_pref < drp->dr_pref
    471  1.1   thorpej 			    || (new_pref == drp->dr_pref
    472  1.1   thorpej 				&& (drp == cur_drp
    473  1.1   thorpej 				    || (new_drp != cur_drp
    474  1.1   thorpej 					&& new_drp->dr_life > drp->dr_life)))))
    475  1.1   thorpej 		    || ((new_st & IS_SICK)
    476  1.1   thorpej 			&& !(drp->dr_ifp->int_state & IS_SICK))) {
    477  1.1   thorpej 			    new_drp = drp;
    478  1.1   thorpej 			    new_st = drp->dr_ifp->int_state;
    479  1.1   thorpej 			    new_pref = drp->dr_pref;
    480  1.1   thorpej 		}
    481  1.1   thorpej 	}
    482  1.1   thorpej 
    483  1.1   thorpej 	/* switch to a better default route
    484  1.1   thorpej 	 */
    485  1.1   thorpej 	if (new_drp != cur_drp) {
    486  1.1   thorpej 		rt = rtget(RIP_DEFAULT, 0);
    487  1.1   thorpej 
    488  1.1   thorpej 		/* Stop using discovered routes if they are all bad
    489  1.1   thorpej 		 */
    490  1.1   thorpej 		if (new_drp == 0) {
    491  1.5  christos 			trace_act("turn off Router Discovery client");
    492  1.1   thorpej 			rdisc_ok = 0;
    493  1.1   thorpej 
    494  1.1   thorpej 			if (rt != 0
    495  1.1   thorpej 			    && (rt->rt_state & RS_RDISC)) {
    496  1.1   thorpej 				rtchange(rt, rt->rt_state & ~RS_RDISC,
    497  1.1   thorpej 					 rt->rt_gate, rt->rt_router,
    498  1.1   thorpej 					 HOPCNT_INFINITY, 0, rt->rt_ifp,
    499  1.1   thorpej 					 now.tv_sec - GARBAGE_TIME, 0);
    500  1.1   thorpej 				rtswitch(rt, 0);
    501  1.1   thorpej 			}
    502  1.1   thorpej 
    503  1.1   thorpej 			/* turn on RIP if permitted */
    504  1.1   thorpej 			rip_on(0);
    505  1.1   thorpej 
    506  1.1   thorpej 		} else {
    507  1.1   thorpej 			if (cur_drp == 0) {
    508  1.1   thorpej 				trace_act("turn on Router Discovery client"
    509  1.5  christos 					  " using %s via %s",
    510  1.1   thorpej 					  naddr_ntoa(new_drp->dr_gate),
    511  1.1   thorpej 					  new_drp->dr_ifp->int_name);
    512  1.1   thorpej 
    513  1.1   thorpej 				rdisc_ok = 1;
    514  1.1   thorpej 
    515  1.1   thorpej 			} else {
    516  1.1   thorpej 				trace_act("switch Router Discovery from"
    517  1.5  christos 					  " %s via %s to %s via %s",
    518  1.1   thorpej 					  naddr_ntoa(cur_drp->dr_gate),
    519  1.1   thorpej 					  cur_drp->dr_ifp->int_name,
    520  1.1   thorpej 					  naddr_ntoa(new_drp->dr_gate),
    521  1.1   thorpej 					  new_drp->dr_ifp->int_name);
    522  1.1   thorpej 			}
    523  1.1   thorpej 
    524  1.1   thorpej 			if (rt != 0) {
    525  1.1   thorpej 				rtchange(rt, rt->rt_state | RS_RDISC,
    526  1.1   thorpej 					 new_drp->dr_gate, new_drp->dr_gate,
    527  1.1   thorpej 					 0,0, new_drp->dr_ifp,
    528  1.1   thorpej 					 now.tv_sec, 0);
    529  1.1   thorpej 			} else {
    530  1.1   thorpej 				rtadd(RIP_DEFAULT, 0,
    531  1.1   thorpej 				      new_drp->dr_gate, new_drp->dr_gate,
    532  1.5  christos 				      HOPCNT_INFINITY-1, 0,
    533  1.5  christos 				      RS_RDISC, new_drp->dr_ifp);
    534  1.1   thorpej 			}
    535  1.1   thorpej 
    536  1.1   thorpej 			/* Now turn off RIP and delete RIP routes,
    537  1.1   thorpej 			 * which might otherwise include the default
    538  1.1   thorpej 			 * we just modified.
    539  1.1   thorpej 			 */
    540  1.1   thorpej 			rip_off();
    541  1.1   thorpej 		}
    542  1.1   thorpej 
    543  1.1   thorpej 		cur_drp = new_drp;
    544  1.1   thorpej 	}
    545  1.1   thorpej }
    546  1.1   thorpej 
    547  1.1   thorpej 
    548  1.1   thorpej /* handle a single address in an advertisement
    549  1.1   thorpej  */
    550  1.1   thorpej static void
    551  1.1   thorpej parse_ad(naddr from,
    552  1.1   thorpej 	 naddr gate,
    553  1.1   thorpej 	 n_long pref,
    554  1.1   thorpej 	 u_short life,
    555  1.1   thorpej 	 struct interface *ifp)
    556  1.1   thorpej {
    557  1.5  christos 	static struct msg_limit bad_gate;
    558  1.1   thorpej 	struct dr *drp, *new_drp;
    559  1.1   thorpej 
    560  1.1   thorpej 
    561  1.1   thorpej 	if (gate == RIP_DEFAULT
    562  1.1   thorpej 	    || !check_dst(gate)) {
    563  1.5  christos 		msglim(&bad_gate, from,"router %s advertising bad gateway %s",
    564  1.5  christos 		       naddr_ntoa(from),
    565  1.5  christos 		       naddr_ntoa(gate));
    566  1.1   thorpej 		return;
    567  1.1   thorpej 	}
    568  1.1   thorpej 
    569  1.1   thorpej 	/* ignore pointers to ourself and routes via unreachable networks
    570  1.1   thorpej 	 */
    571  1.1   thorpej 	if (ifwithaddr(gate, 1, 0) != 0) {
    572  1.5  christos 		trace_pkt("    discard Router Discovery Ad pointing at us");
    573  1.1   thorpej 		return;
    574  1.1   thorpej 	}
    575  1.1   thorpej 	if (!on_net(gate, ifp->int_net, ifp->int_mask)) {
    576  1.5  christos 		trace_pkt("    discard Router Discovery Ad"
    577  1.5  christos 			  " toward unreachable net");
    578  1.1   thorpej 		return;
    579  1.1   thorpej 	}
    580  1.1   thorpej 
    581  1.1   thorpej 	/* Convert preference to an unsigned value
    582  1.1   thorpej 	 * and later bias it by the metric of the interface.
    583  1.1   thorpej 	 */
    584  1.1   thorpej 	pref = ntohl(pref) ^ MIN_PreferenceLevel;
    585  1.4  christos 
    586  1.1   thorpej 	if (pref == 0 || life == 0) {
    587  1.1   thorpej 		pref = 0;
    588  1.1   thorpej 		life = 0;
    589  1.1   thorpej 	}
    590  1.1   thorpej 
    591  1.1   thorpej 	for (new_drp = 0, drp = drs; drp < &drs[MAX_ADS]; drp++) {
    592  1.1   thorpej 		/* accept new info for a familiar entry
    593  1.1   thorpej 		 */
    594  1.1   thorpej 		if (drp->dr_gate == gate) {
    595  1.1   thorpej 			new_drp = drp;
    596  1.1   thorpej 			break;
    597  1.1   thorpej 		}
    598  1.1   thorpej 
    599  1.1   thorpej 		if (life == 0)
    600  1.1   thorpej 			continue;	/* do not worry about dead ads */
    601  1.1   thorpej 
    602  1.1   thorpej 		if (drp->dr_ts == 0) {
    603  1.1   thorpej 			new_drp = drp;	/* use unused entry */
    604  1.1   thorpej 
    605  1.1   thorpej 		} else if (new_drp == 0) {
    606  1.1   thorpej 			/* look for an entry worse than the new one to
    607  1.1   thorpej 			 * reuse.
    608  1.1   thorpej 			 */
    609  1.1   thorpej 			if ((!(ifp->int_state & IS_SICK)
    610  1.1   thorpej 			     && (drp->dr_ifp->int_state & IS_SICK))
    611  1.1   thorpej 			    || (pref > drp->dr_pref
    612  1.1   thorpej 				&& !((ifp->int_state ^ drp->dr_ifp->int_state)
    613  1.1   thorpej 				     & IS_SICK)))
    614  1.1   thorpej 				new_drp = drp;
    615  1.1   thorpej 
    616  1.1   thorpej 		} else if (new_drp->dr_ts != 0) {
    617  1.1   thorpej 			/* look for the least valueable entry to reuse
    618  1.1   thorpej 			 */
    619  1.1   thorpej 			if ((!(new_drp->dr_ifp->int_state & IS_SICK)
    620  1.1   thorpej 			     && (drp->dr_ifp->int_state & IS_SICK))
    621  1.1   thorpej 			    || (new_drp->dr_pref > drp->dr_pref
    622  1.1   thorpej 				&& !((new_drp->dr_ifp->int_state
    623  1.1   thorpej 				      ^ drp->dr_ifp->int_state)
    624  1.1   thorpej 				     & IS_SICK)))
    625  1.1   thorpej 				new_drp = drp;
    626  1.1   thorpej 		}
    627  1.1   thorpej 	}
    628  1.1   thorpej 
    629  1.1   thorpej 	/* forget it if all of the current entries are better */
    630  1.1   thorpej 	if (new_drp == 0)
    631  1.1   thorpej 		return;
    632  1.1   thorpej 
    633  1.1   thorpej 	new_drp->dr_ifp = ifp;
    634  1.1   thorpej 	new_drp->dr_gate = gate;
    635  1.1   thorpej 	new_drp->dr_ts = now.tv_sec;
    636  1.1   thorpej 	new_drp->dr_life = ntohs(life);
    637  1.1   thorpej 	new_drp->dr_recv_pref = pref;
    638  1.1   thorpej 	/* bias functional preference by metric of the interface */
    639  1.1   thorpej 	new_drp->dr_pref = PREF(pref,ifp);
    640  1.1   thorpej 
    641  1.1   thorpej 	/* after hearing a good advertisement, stop asking
    642  1.1   thorpej 	 */
    643  1.1   thorpej 	if (!(ifp->int_state & IS_SICK))
    644  1.1   thorpej 		ifp->int_rdisc_cnt = MAX_SOLICITATIONS;
    645  1.1   thorpej }
    646  1.1   thorpej 
    647  1.1   thorpej 
    648  1.1   thorpej /* Compute the IP checksum
    649  1.1   thorpej  *	This assumes the packet is less than 32K long.
    650  1.1   thorpej  */
    651  1.1   thorpej static u_short
    652  1.1   thorpej in_cksum(u_short *p,
    653  1.1   thorpej 	 u_int len)
    654  1.1   thorpej {
    655  1.1   thorpej 	u_int sum = 0;
    656  1.1   thorpej 	int nwords = len >> 1;
    657  1.1   thorpej 
    658  1.1   thorpej 	while (nwords-- != 0)
    659  1.1   thorpej 		sum += *p++;
    660  1.1   thorpej 
    661  1.1   thorpej 	if (len & 1)
    662  1.1   thorpej 		sum += *(u_char *)p;
    663  1.1   thorpej 
    664  1.1   thorpej 	/* end-around-carry */
    665  1.1   thorpej 	sum = (sum >> 16) + (sum & 0xffff);
    666  1.1   thorpej 	sum += (sum >> 16);
    667  1.1   thorpej 	return (~sum);
    668  1.1   thorpej }
    669  1.1   thorpej 
    670  1.1   thorpej 
    671  1.1   thorpej /* Send a router discovery advertisement or solicitation ICMP packet.
    672  1.1   thorpej  */
    673  1.1   thorpej static void
    674  1.1   thorpej send_rdisc(union ad_u *p,
    675  1.1   thorpej 	   int p_size,
    676  1.1   thorpej 	   struct interface *ifp,
    677  1.1   thorpej 	   naddr dst,			/* 0 or unicast destination */
    678  1.1   thorpej 	   int	type)			/* 0=unicast, 1=bcast, 2=mcast */
    679  1.1   thorpej {
    680  1.1   thorpej 	struct sockaddr_in sin;
    681  1.1   thorpej 	int flags;
    682  1.1   thorpej 	char *msg;
    683  1.1   thorpej 	naddr tgt_mcast;
    684  1.1   thorpej 
    685  1.1   thorpej 
    686  1.6     lukem 	memset(&sin, 0, sizeof(sin));
    687  1.4  christos 	sin.sin_addr.s_addr = dst;
    688  1.3   mycroft 	sin.sin_family = AF_INET;
    689  1.4  christos #ifdef _HAVE_SIN_LEN
    690  1.3   mycroft 	sin.sin_len = sizeof(sin);
    691  1.4  christos #endif
    692  1.1   thorpej 	flags = MSG_DONTROUTE;
    693  1.1   thorpej 
    694  1.1   thorpej 	switch (type) {
    695  1.1   thorpej 	case 0:				/* unicast */
    696  1.5  christos 	default:
    697  1.1   thorpej 		msg = "Send";
    698  1.1   thorpej 		break;
    699  1.1   thorpej 
    700  1.1   thorpej 	case 1:				/* broadcast */
    701  1.1   thorpej 		if (ifp->int_if_flags & IFF_POINTOPOINT) {
    702  1.1   thorpej 			msg = "Send pt-to-pt";
    703  1.1   thorpej 			sin.sin_addr.s_addr = ifp->int_dstaddr;
    704  1.1   thorpej 		} else {
    705  1.1   thorpej 			msg = "Send broadcast";
    706  1.1   thorpej 			sin.sin_addr.s_addr = ifp->int_brdaddr;
    707  1.1   thorpej 		}
    708  1.1   thorpej 		break;
    709  1.1   thorpej 
    710  1.1   thorpej 	case 2:				/* multicast */
    711  1.1   thorpej 		msg = "Send multicast";
    712  1.1   thorpej 		if (ifp->int_state & IS_DUP) {
    713  1.1   thorpej 			trace_act("abort multicast output via %s"
    714  1.5  christos 				  " with duplicate address",
    715  1.1   thorpej 				  ifp->int_name);
    716  1.1   thorpej 			return;
    717  1.1   thorpej 		}
    718  1.1   thorpej 		if (rdisc_sock_mcast != ifp) {
    719  1.1   thorpej 			/* select the right interface. */
    720  1.1   thorpej #ifdef MCAST_PPP_BUG
    721  1.1   thorpej 			/* Do not specifiy the primary interface explicitly
    722  1.1   thorpej 			 * if we have the multicast point-to-point kernel
    723  1.1   thorpej 			 * bug, since the kernel will do the wrong thing
    724  1.1   thorpej 			 * if the local address of a point-to-point link
    725  1.1   thorpej 			 * is the same as the address of an ordinary
    726  1.1   thorpej 			 * interface.
    727  1.1   thorpej 			 */
    728  1.1   thorpej 			if (ifp->int_addr == myaddr) {
    729  1.1   thorpej 				tgt_mcast = 0;
    730  1.1   thorpej 			} else
    731  1.1   thorpej #endif
    732  1.1   thorpej 			tgt_mcast = ifp->int_addr;
    733  1.1   thorpej 			if (0 > setsockopt(rdisc_sock,
    734  1.1   thorpej 					   IPPROTO_IP, IP_MULTICAST_IF,
    735  1.1   thorpej 					   &tgt_mcast, sizeof(tgt_mcast))) {
    736  1.1   thorpej 				LOGERR("setsockopt(rdisc_sock,"
    737  1.1   thorpej 				       "IP_MULTICAST_IF)");
    738  1.1   thorpej 				rdisc_sock_mcast = 0;
    739  1.1   thorpej 				return;
    740  1.1   thorpej 			}
    741  1.1   thorpej 			rdisc_sock_mcast = ifp;
    742  1.1   thorpej 		}
    743  1.1   thorpej 		flags = 0;
    744  1.1   thorpej 		break;
    745  1.1   thorpej 	}
    746  1.4  christos 
    747  1.4  christos 	if (rdisc_sock < 0)
    748  1.4  christos 		get_rdisc_sock();
    749  1.1   thorpej 
    750  1.1   thorpej 	trace_rdisc(msg, ifp->int_addr, sin.sin_addr.s_addr, ifp,
    751  1.1   thorpej 		    p, p_size);
    752  1.1   thorpej 
    753  1.1   thorpej 	if (0 > sendto(rdisc_sock, p, p_size, flags,
    754  1.1   thorpej 		       (struct sockaddr *)&sin, sizeof(sin))) {
    755  1.1   thorpej 		if (ifp == 0 || !(ifp->int_state & IS_BROKE))
    756  1.1   thorpej 			msglog("sendto(%s%s%s): %s",
    757  1.1   thorpej 			       ifp != 0 ? ifp->int_name : "",
    758  1.1   thorpej 			       ifp != 0 ? ", " : "",
    759  1.1   thorpej 			       inet_ntoa(sin.sin_addr),
    760  1.1   thorpej 			       strerror(errno));
    761  1.1   thorpej 		if (ifp != 0)
    762  1.1   thorpej 			if_sick(ifp);
    763  1.1   thorpej 	}
    764  1.1   thorpej }
    765  1.1   thorpej 
    766  1.1   thorpej 
    767  1.1   thorpej /* Send an advertisement
    768  1.1   thorpej  */
    769  1.1   thorpej static void
    770  1.1   thorpej send_adv(struct interface *ifp,
    771  1.1   thorpej 	 naddr	dst,			/* 0 or unicast destination */
    772  1.1   thorpej 	 int	type)			/* 0=unicast, 1=bcast, 2=mcast */
    773  1.1   thorpej {
    774  1.1   thorpej 	union ad_u u;
    775  1.1   thorpej 	n_long pref;
    776  1.1   thorpej 
    777  1.1   thorpej 
    778  1.6     lukem 	memset(&u, 0, sizeof(u.ad));
    779  1.1   thorpej 
    780  1.1   thorpej 	u.ad.icmp_type = ICMP_ROUTERADVERT;
    781  1.1   thorpej 	u.ad.icmp_ad_num = 1;
    782  1.1   thorpej 	u.ad.icmp_ad_asize = sizeof(u.ad.icmp_ad_info[0])/4;
    783  1.1   thorpej 
    784  1.1   thorpej 	u.ad.icmp_ad_life = stopint ? 0 : htons(ifp->int_rdisc_int*3);
    785  1.1   thorpej 	pref = ifp->int_rdisc_pref ^ MIN_PreferenceLevel;
    786  1.1   thorpej 	pref = PREF(pref, ifp) ^ MIN_PreferenceLevel;
    787  1.1   thorpej 	u.ad.icmp_ad_info[0].icmp_ad_pref = htonl(pref);
    788  1.1   thorpej 
    789  1.1   thorpej 	u.ad.icmp_ad_info[0].icmp_ad_addr = ifp->int_addr;
    790  1.1   thorpej 
    791  1.1   thorpej 	u.ad.icmp_cksum = in_cksum((u_short*)&u.ad, sizeof(u.ad));
    792  1.1   thorpej 
    793  1.1   thorpej 	send_rdisc(&u, sizeof(u.ad), ifp, dst, type);
    794  1.1   thorpej }
    795  1.1   thorpej 
    796  1.1   thorpej 
    797  1.1   thorpej /* Advertise for Router Discovery
    798  1.1   thorpej  */
    799  1.1   thorpej void
    800  1.1   thorpej rdisc_adv(void)
    801  1.1   thorpej {
    802  1.1   thorpej 	struct interface *ifp;
    803  1.1   thorpej 
    804  1.5  christos 	if (!supplier)
    805  1.5  christos 		return;
    806  1.1   thorpej 
    807  1.1   thorpej 	rdisc_timer.tv_sec = now.tv_sec + NEVER;
    808  1.1   thorpej 
    809  1.1   thorpej 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
    810  1.5  christos 		if (0 != (ifp->int_state & (IS_NO_ADV_OUT | IS_BROKE)))
    811  1.1   thorpej 			continue;
    812  1.1   thorpej 
    813  1.1   thorpej 		if (!timercmp(&ifp->int_rdisc_timer, &now, >)
    814  1.1   thorpej 		    || stopint) {
    815  1.1   thorpej 			send_adv(ifp, htonl(INADDR_ALLHOSTS_GROUP),
    816  1.1   thorpej 				 (ifp->int_state&IS_BCAST_RDISC) ? 1 : 2);
    817  1.1   thorpej 			ifp->int_rdisc_cnt++;
    818  1.1   thorpej 
    819  1.1   thorpej 			intvl_random(&ifp->int_rdisc_timer,
    820  1.1   thorpej 				     (ifp->int_rdisc_int*3)/4,
    821  1.1   thorpej 				     ifp->int_rdisc_int);
    822  1.1   thorpej 			if (ifp->int_rdisc_cnt < MAX_INITIAL_ADVERTS
    823  1.1   thorpej 			    && (ifp->int_rdisc_timer.tv_sec
    824  1.1   thorpej 				> MAX_INITIAL_ADVERT_INTERVAL)) {
    825  1.1   thorpej 				ifp->int_rdisc_timer.tv_sec
    826  1.1   thorpej 				= MAX_INITIAL_ADVERT_INTERVAL;
    827  1.1   thorpej 			}
    828  1.1   thorpej 			timevaladd(&ifp->int_rdisc_timer, &now);
    829  1.1   thorpej 		}
    830  1.1   thorpej 
    831  1.1   thorpej 		if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
    832  1.1   thorpej 			rdisc_timer = ifp->int_rdisc_timer;
    833  1.1   thorpej 	}
    834  1.1   thorpej }
    835  1.1   thorpej 
    836  1.1   thorpej 
    837  1.1   thorpej /* Solicit for Router Discovery
    838  1.1   thorpej  */
    839  1.1   thorpej void
    840  1.1   thorpej rdisc_sol(void)
    841  1.1   thorpej {
    842  1.1   thorpej 	struct interface *ifp;
    843  1.1   thorpej 	union ad_u u;
    844  1.1   thorpej 
    845  1.1   thorpej 
    846  1.5  christos 	if (supplier)
    847  1.5  christos 		return;
    848  1.5  christos 
    849  1.1   thorpej 	rdisc_timer.tv_sec = now.tv_sec + NEVER;
    850  1.1   thorpej 
    851  1.1   thorpej 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
    852  1.5  christos 		if (0 != (ifp->int_state & (IS_NO_SOL_OUT | IS_BROKE))
    853  1.1   thorpej 		    || ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
    854  1.1   thorpej 			continue;
    855  1.1   thorpej 
    856  1.1   thorpej 		if (!timercmp(&ifp->int_rdisc_timer, &now, >)) {
    857  1.6     lukem 			memset(&u, 0, sizeof(u.so));
    858  1.1   thorpej 			u.so.icmp_type = ICMP_ROUTERSOLICIT;
    859  1.1   thorpej 			u.so.icmp_cksum = in_cksum((u_short*)&u.so,
    860  1.1   thorpej 						   sizeof(u.so));
    861  1.1   thorpej 			send_rdisc(&u, sizeof(u.so), ifp,
    862  1.1   thorpej 				   htonl(INADDR_ALLROUTERS_GROUP),
    863  1.1   thorpej 				   ((ifp->int_state&IS_BCAST_RDISC) ? 1 : 2));
    864  1.1   thorpej 
    865  1.1   thorpej 			if (++ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
    866  1.1   thorpej 				continue;
    867  1.1   thorpej 
    868  1.1   thorpej 			ifp->int_rdisc_timer.tv_sec = SOLICITATION_INTERVAL;
    869  1.1   thorpej 			ifp->int_rdisc_timer.tv_usec = 0;
    870  1.1   thorpej 			timevaladd(&ifp->int_rdisc_timer, &now);
    871  1.1   thorpej 		}
    872  1.1   thorpej 
    873  1.1   thorpej 		if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
    874  1.1   thorpej 			rdisc_timer = ifp->int_rdisc_timer;
    875  1.1   thorpej 	}
    876  1.1   thorpej }
    877  1.1   thorpej 
    878  1.1   thorpej 
    879  1.1   thorpej /* check the IP header of a possible Router Discovery ICMP packet */
    880  1.1   thorpej static struct interface *		/* 0 if bad */
    881  1.1   thorpej ck_icmp(char	*act,
    882  1.1   thorpej 	naddr	from,
    883  1.5  christos 	struct interface *ifp,
    884  1.1   thorpej 	naddr	to,
    885  1.1   thorpej 	union ad_u *p,
    886  1.1   thorpej 	u_int	len)
    887  1.1   thorpej {
    888  1.1   thorpej 	char *type;
    889  1.1   thorpej 
    890  1.1   thorpej 
    891  1.1   thorpej 	if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
    892  1.1   thorpej 		type = "advertisement";
    893  1.1   thorpej 	} else if (p->icmp.icmp_type == ICMP_ROUTERSOLICIT) {
    894  1.1   thorpej 		type = "solicitation";
    895  1.1   thorpej 	} else {
    896  1.1   thorpej 		return 0;
    897  1.1   thorpej 	}
    898  1.1   thorpej 
    899  1.1   thorpej 	if (p->icmp.icmp_code != 0) {
    900  1.5  christos 		trace_pkt("unrecognized ICMP Router %s code=%d from %s to %s",
    901  1.1   thorpej 			  type, p->icmp.icmp_code,
    902  1.1   thorpej 			  naddr_ntoa(from), naddr_ntoa(to));
    903  1.1   thorpej 		return 0;
    904  1.1   thorpej 	}
    905  1.1   thorpej 
    906  1.1   thorpej 	trace_rdisc(act, from, to, ifp, p, len);
    907  1.1   thorpej 
    908  1.1   thorpej 	if (ifp == 0)
    909  1.1   thorpej 		trace_pkt("unknown interface for router-discovery %s"
    910  1.1   thorpej 			  " from %s to %s",
    911  1.1   thorpej 			  type, naddr_ntoa(from), naddr_ntoa(to));
    912  1.1   thorpej 
    913  1.1   thorpej 	return ifp;
    914  1.1   thorpej }
    915  1.1   thorpej 
    916  1.1   thorpej 
    917  1.1   thorpej /* read packets from the router discovery socket
    918  1.1   thorpej  */
    919  1.1   thorpej void
    920  1.1   thorpej read_d(void)
    921  1.1   thorpej {
    922  1.5  christos 	static struct msg_limit bad_asize, bad_len;
    923  1.5  christos #ifdef USE_PASSIFNAME
    924  1.5  christos 	static struct msg_limit  bad_name;
    925  1.5  christos #endif
    926  1.1   thorpej 	struct sockaddr_in from;
    927  1.1   thorpej 	int n, fromlen, cc, hlen;
    928  1.5  christos 	struct {
    929  1.5  christos #ifdef USE_PASSIFNAME
    930  1.5  christos 		char	ifname[IFNAMSIZ];
    931  1.5  christos #endif
    932  1.5  christos 		union {
    933  1.5  christos 			struct ip ip;
    934  1.5  christos 			u_short s[512/2];
    935  1.5  christos 			u_char	b[512];
    936  1.5  christos 		} pkt;
    937  1.5  christos 	} buf;
    938  1.1   thorpej 	union ad_u *p;
    939  1.1   thorpej 	n_long *wp;
    940  1.1   thorpej 	struct interface *ifp;
    941  1.1   thorpej 
    942  1.1   thorpej 
    943  1.1   thorpej 	for (;;) {
    944  1.1   thorpej 		fromlen = sizeof(from);
    945  1.5  christos 		cc = recvfrom(rdisc_sock, &buf, sizeof(buf), 0,
    946  1.1   thorpej 			      (struct sockaddr*)&from,
    947  1.1   thorpej 			      &fromlen);
    948  1.1   thorpej 		if (cc <= 0) {
    949  1.1   thorpej 			if (cc < 0 && errno != EWOULDBLOCK)
    950  1.1   thorpej 				LOGERR("recvfrom(rdisc_sock)");
    951  1.1   thorpej 			break;
    952  1.1   thorpej 		}
    953  1.1   thorpej 		if (fromlen != sizeof(struct sockaddr_in))
    954  1.1   thorpej 			logbad(1,"impossible recvfrom(rdisc_sock) fromlen=%d",
    955  1.1   thorpej 			       fromlen);
    956  1.5  christos #ifdef USE_PASSIFNAME
    957  1.5  christos 		if ((cc -= sizeof(buf.ifname)) < 0)
    958  1.5  christos 			logbad(0,"missing USE_PASSIFNAME; only %d bytes",
    959  1.5  christos 			       cc+sizeof(buf.ifname));
    960  1.5  christos #endif
    961  1.1   thorpej 
    962  1.5  christos 		hlen = buf.pkt.ip.ip_hl << 2;
    963  1.1   thorpej 		if (cc < hlen + ICMP_MINLEN)
    964  1.1   thorpej 			continue;
    965  1.5  christos 		p = (union ad_u *)&buf.pkt.b[hlen];
    966  1.1   thorpej 		cc -= hlen;
    967  1.1   thorpej 
    968  1.5  christos #ifdef USE_PASSIFNAME
    969  1.5  christos 		ifp = ifwithname(buf.ifname, 0);
    970  1.5  christos 		if (ifp == 0)
    971  1.5  christos 			msglim(&bad_name, from.sin_addr.s_addr,
    972  1.5  christos 			       "impossible rdisc if_ name %.*s",
    973  1.5  christos 			       IFNAMSIZ, buf.ifname);
    974  1.5  christos #else
    975  1.5  christos 		/* If we could tell the interface on which a packet from
    976  1.5  christos 		 * address 0 arrived, we could deal with such solicitations.
    977  1.5  christos 		 */
    978  1.5  christos 		ifp = ((from.sin_addr.s_addr == 0)
    979  1.5  christos 		       ? 0 : iflookup(from.sin_addr.s_addr));
    980  1.5  christos #endif
    981  1.5  christos 		ifp = ck_icmp("Recv", from.sin_addr.s_addr, ifp,
    982  1.5  christos 			      buf.pkt.ip.ip_dst.s_addr, p, cc);
    983  1.1   thorpej 		if (ifp == 0)
    984  1.1   thorpej 			continue;
    985  1.1   thorpej 		if (ifwithaddr(from.sin_addr.s_addr, 0, 0)) {
    986  1.5  christos 			trace_pkt("    "
    987  1.5  christos 				  "discard our own Router Discovery message");
    988  1.1   thorpej 			continue;
    989  1.1   thorpej 		}
    990  1.1   thorpej 
    991  1.1   thorpej 		switch (p->icmp.icmp_type) {
    992  1.1   thorpej 		case ICMP_ROUTERADVERT:
    993  1.1   thorpej 			if (p->ad.icmp_ad_asize*4
    994  1.1   thorpej 			    < sizeof(p->ad.icmp_ad_info[0])) {
    995  1.5  christos 				msglim(&bad_asize, from.sin_addr.s_addr,
    996  1.5  christos 				       "intolerable rdisc address size=%d",
    997  1.5  christos 				       p->ad.icmp_ad_asize);
    998  1.1   thorpej 				continue;
    999  1.1   thorpej 			}
   1000  1.1   thorpej 			if (p->ad.icmp_ad_num == 0) {
   1001  1.5  christos 				trace_pkt("    empty?");
   1002  1.1   thorpej 				continue;
   1003  1.1   thorpej 			}
   1004  1.1   thorpej 			if (cc != (sizeof(p->ad) - sizeof(p->ad.icmp_ad_info)
   1005  1.1   thorpej 				   + (p->ad.icmp_ad_num
   1006  1.1   thorpej 				      * sizeof(p->ad.icmp_ad_info[0])))) {
   1007  1.5  christos 				msglim(&bad_len, from.sin_addr.s_addr,
   1008  1.5  christos 				       "rdisc length %d does not match ad_num"
   1009  1.5  christos 				       " %d", cc, p->ad.icmp_ad_num);
   1010  1.1   thorpej 				continue;
   1011  1.1   thorpej 			}
   1012  1.1   thorpej 			if (supplier)
   1013  1.1   thorpej 				continue;
   1014  1.1   thorpej 			if (ifp->int_state & IS_NO_ADV_IN)
   1015  1.1   thorpej 				continue;
   1016  1.1   thorpej 
   1017  1.1   thorpej 			wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
   1018  1.1   thorpej 			for (n = 0; n < p->ad.icmp_ad_num; n++) {
   1019  1.1   thorpej 				parse_ad(from.sin_addr.s_addr,
   1020  1.1   thorpej 					 wp[0], wp[1],
   1021  1.1   thorpej 					 ntohs(p->ad.icmp_ad_life),
   1022  1.1   thorpej 					 ifp);
   1023  1.1   thorpej 				wp += p->ad.icmp_ad_asize;
   1024  1.1   thorpej 			}
   1025  1.1   thorpej 			break;
   1026  1.1   thorpej 
   1027  1.1   thorpej 
   1028  1.1   thorpej 		case ICMP_ROUTERSOLICIT:
   1029  1.1   thorpej 			if (!supplier)
   1030  1.1   thorpej 				continue;
   1031  1.1   thorpej 			if (ifp->int_state & IS_NO_ADV_OUT)
   1032  1.1   thorpej 				continue;
   1033  1.1   thorpej 
   1034  1.1   thorpej 			/* XXX
   1035  1.1   thorpej 			 * We should handle messages from address 0.
   1036  1.1   thorpej 			 */
   1037  1.1   thorpej 
   1038  1.1   thorpej 			/* Respond with a point-to-point advertisement */
   1039  1.1   thorpej 			send_adv(ifp, from.sin_addr.s_addr, 0);
   1040  1.1   thorpej 			break;
   1041  1.1   thorpej 		}
   1042  1.1   thorpej 	}
   1043  1.1   thorpej 
   1044  1.1   thorpej 	rdisc_sort();
   1045  1.1   thorpej }
   1046