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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
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13 * 3. All advertising materials mentioning features or use of this software
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15 * This product includes software developed by the University of
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33 * $FreeBSD: src/sbin/routed/rdisc.c,v 1.5.2.1 2000/08/14 17:00:04 sheldonh Exp $
37 #include <netinet/in_systm.h>
38 #include <netinet/ip.h>
39 #include <netinet/ip_icmp.h>
41 #if !defined(sgi) && !defined(__NetBSD__)
42 static char sccsid[] __attribute__((unused)) = "@(#)rdisc.c 8.1 (Berkeley) x/y/95";
43 #elif defined(__NetBSD__)
47 /* router advertisement ICMP packet */
49 u_int8_t icmp_type; /* type of message */
50 u_int8_t icmp_code; /* type sub code */
51 u_int16_t icmp_cksum; /* ones complement cksum of struct */
52 u_int8_t icmp_ad_num; /* # of following router addresses */
53 u_int8_t icmp_ad_asize; /* 2--words in each advertisement */
54 u_int16_t icmp_ad_life; /* seconds of validity */
61 /* router solicitation ICMP packet */
63 u_int8_t icmp_type; /* type of message */
64 u_int8_t icmp_code; /* type sub code */
65 u_int16_t icmp_cksum; /* ones complement cksum of struct */
76 int rdisc_sock = -1; /* router-discovery raw socket */
77 struct interface *rdisc_sock_mcast; /* current multicast interface */
79 struct timeval rdisc_timer;
80 int rdisc_ok; /* using solicited route */
83 #define MAX_ADS 16 /* at least one per interface */
84 struct dr { /* accumulated advertisements */
85 struct interface *dr_ifp;
86 naddr dr_gate; /* gateway */
87 time_t dr_ts; /* when received */
88 time_t dr_life; /* lifetime in host byte order */
89 n_long dr_recv_pref; /* received but biased preference */
90 n_long dr_pref; /* preference adjusted by metric */
91 } *cur_drp, drs[MAX_ADS];
93 /* convert between signed, balanced around zero,
94 * and unsigned zero-based preferences */
95 #define SIGN_PREF(p) ((p) ^ MIN_PreferenceLevel)
96 #define UNSIGN_PREF(p) SIGN_PREF(p)
97 /* adjust unsigned preference by interface metric,
98 * without driving it to infinity */
99 #define PREF(p, ifp) ((int)(p) <= (ifp)->int_metric ? ((p) != 0 ? 1 : 0) \
100 : (p) - ((ifp)->int_metric))
102 static void rdisc_sort(void);
105 /* dump an ICMP Router Discovery Advertisement Message
108 trace_rdisc(const char *act,
111 struct interface *ifp,
119 if (!TRACEPACKETS || ftrace == 0)
124 if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
125 fprintf(ftrace, "%s Router Ad"
126 " from %s to %s via %s life=%d\n",
127 act, naddr_ntoa(from), naddr_ntoa(to),
128 ifp ? ifp->int_name : "?",
129 ntohs(p->ad.icmp_ad_life));
133 wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
134 lim = &wp[(len - sizeof(p->ad)) / sizeof(*wp)];
135 for (i = 0; i < p->ad.icmp_ad_num && wp <= lim; i++) {
136 fprintf(ftrace, "\t%s preference=%d",
137 naddr_ntoa(wp[0]), (int)ntohl(wp[1]));
138 wp += p->ad.icmp_ad_asize;
143 trace_act("%s Router Solic. from %s to %s via %s value=%#x",
144 act, naddr_ntoa(from), naddr_ntoa(to),
145 ifp ? ifp->int_name : "?",
146 (int)ntohl(p->so.icmp_so_rsvd));
150 /* prepare Router Discovery socket.
155 if (rdisc_sock < 0) {
156 rdisc_sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
158 BADERR(1,"rdisc_sock = socket()");
159 fix_sock(rdisc_sock,"rdisc_sock");
165 /* Pick multicast group for router-discovery socket
168 set_rdisc_mg(struct interface *ifp,
169 int on) /* 0=turn it off */
173 if (rdisc_sock < 0) {
174 /* Create the raw socket so that we can hear at least
175 * broadcast router discovery packets.
177 if ((ifp->int_state & IS_NO_RDISC) == IS_NO_RDISC
183 if (!(ifp->int_if_flags & IFF_MULTICAST)) {
184 ifp->int_state &= ~(IS_ALL_HOSTS | IS_ALL_ROUTERS);
189 if (ifp->int_if_flags & IFF_POINTOPOINT)
192 memset(&m, 0, sizeof(m));
193 m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
197 || (ifp->int_state & IS_NO_ADV_IN)
199 /* stop listening to advertisements
201 if (ifp->int_state & IS_ALL_HOSTS) {
202 m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
203 if (setsockopt(rdisc_sock, IPPROTO_IP,
206 LOGERR("IP_DROP_MEMBERSHIP ALLHOSTS");
207 ifp->int_state &= ~IS_ALL_HOSTS;
210 } else if (!(ifp->int_state & IS_ALL_HOSTS)) {
211 /* start listening to advertisements
213 m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
214 if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
215 &m, sizeof(m)) < 0) {
216 LOGERR("IP_ADD_MEMBERSHIP ALLHOSTS");
218 ifp->int_state |= IS_ALL_HOSTS;
223 || (ifp->int_state & IS_NO_ADV_OUT)
225 /* stop listening to solicitations
227 if (ifp->int_state & IS_ALL_ROUTERS) {
228 m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
229 if (setsockopt(rdisc_sock, IPPROTO_IP,
232 LOGERR("IP_DROP_MEMBERSHIP ALLROUTERS");
233 ifp->int_state &= ~IS_ALL_ROUTERS;
236 } else if (!(ifp->int_state & IS_ALL_ROUTERS)) {
237 /* start hearing solicitations
239 m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
240 if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
241 &m, sizeof(m)) < 0) {
242 LOGERR("IP_ADD_MEMBERSHIP ALLROUTERS");
244 ifp->int_state |= IS_ALL_ROUTERS;
250 /* start supplying routes
255 struct interface *ifp;
261 trace_act("start supplying routes");
263 /* Forget discovered routes.
265 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
266 drp->dr_recv_pref = 0;
274 /* Do not start advertising until we have heard some RIP routes */
275 LIM_SEC(rdisc_timer, now.tv_sec+MIN_WAITTIME);
277 /* Switch router discovery multicast groups from soliciting
280 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
281 if (ifp->int_state & IS_BROKE)
283 ifp->int_rdisc_cnt = 0;
284 ifp->int_rdisc_timer.tv_usec = rdisc_timer.tv_usec;
285 ifp->int_rdisc_timer.tv_sec = now.tv_sec+MIN_WAITTIME;
286 set_rdisc_mg(ifp, 1);
289 /* get rid of any redirects */
294 /* age discovered routes and find the best one
297 rdisc_age(naddr bad_gate)
303 /* If only advertising, then do only that. */
305 /* If switching from client to server, get rid of old
314 /* If we are being told about a bad router,
315 * then age the discovered default route, and if there is
316 * no alternative, solicit a replacement.
319 /* Look for the bad discovered default route.
320 * Age it and note its interface.
322 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
326 /* When we find the bad router, then age the route
327 * to at most SUPPLY_INTERVAL.
328 * This is contrary to RFC 1256, but defends against
331 if (drp->dr_gate == bad_gate) {
332 sec = (now.tv_sec - drp->dr_life
334 if (drp->dr_ts > sec) {
335 trace_act("age 0.0.0.0 --> %s via %s",
336 naddr_ntoa(drp->dr_gate),
337 drp->dr_ifp->int_name);
348 /* Delete old redirected routes to keep the kernel table small,
349 * and to prevent black holes. Check that the kernel table
350 * matches the daemon table (i.e. has the default route).
351 * But only if RIP is not running and we are not dealing with
352 * a bad gateway, since otherwise age() will be called.
354 if (rip_sock < 0 && bad_gate == 0)
359 /* Zap all routes discovered via an interface that has gone bad
360 * This should only be called when !(ifp->int_state & IS_ALIAS)
363 if_bad_rdisc(struct interface *ifp)
367 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
368 if (drp->dr_ifp != ifp)
370 drp->dr_recv_pref = 0;
375 /* make a note to re-solicit, turn RIP on or off, etc. */
376 rdisc_timer.tv_sec = 0;
380 /* mark an interface ok for router discovering.
383 if_ok_rdisc(struct interface *ifp)
385 set_rdisc_mg(ifp, 1);
387 ifp->int_rdisc_cnt = 0;
388 ifp->int_rdisc_timer.tv_sec = now.tv_sec + (supplier
390 : MAX_SOLICITATION_DELAY);
391 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
392 rdisc_timer = ifp->int_rdisc_timer;
396 /* get rid of a dead discovered router
399 del_rdisc(struct dr *drp)
401 struct interface *ifp;
406 del_redirects(gate = drp->dr_gate, 0);
411 /* Count the other discovered routes on the interface.
415 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
417 && drp->dr_ifp == ifp)
421 /* If that was the last good discovered router on the interface,
422 * then solicit a new one.
423 * This is contrary to RFC 1256, but defends against black holes.
426 trace_act("discovered router %s via %s"
427 " is bad--have %d remaining",
428 naddr_ntoa(gate), ifp->int_name, i);
429 } else if (ifp->int_rdisc_cnt >= MAX_SOLICITATIONS) {
430 trace_act("last discovered router %s via %s"
431 " is bad--re-solicit",
432 naddr_ntoa(gate), ifp->int_name);
433 ifp->int_rdisc_cnt = 0;
434 ifp->int_rdisc_timer.tv_sec = 0;
437 trace_act("last discovered router %s via %s"
438 " is bad--wait to solicit",
439 naddr_ntoa(gate), ifp->int_name);
444 /* Find the best discovered route,
445 * and discard stale routers.
450 struct dr *drp, *new_drp;
453 struct interface *ifp;
458 /* Find the best discovered route.
461 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
466 /* Get rid of expired discovered routers.
468 if (drp->dr_ts + drp->dr_life <= now.tv_sec) {
473 LIM_SEC(rdisc_timer, drp->dr_ts+drp->dr_life+1);
475 /* Update preference with possibly changed interface
478 drp->dr_pref = PREF(drp->dr_recv_pref, ifp);
480 /* Prefer the current route to prevent thrashing.
481 * Prefer shorter lifetimes to speed the detection of
483 * Avoid sick interfaces.
486 || (!((new_st ^ drp->dr_ifp->int_state) & IS_SICK)
487 && (new_pref < drp->dr_pref
488 || (new_pref == drp->dr_pref
490 || (new_drp != cur_drp
491 && new_drp->dr_life > drp->dr_life)))))
492 || ((new_st & IS_SICK)
493 && !(drp->dr_ifp->int_state & IS_SICK))) {
495 new_st = drp->dr_ifp->int_state;
496 new_pref = drp->dr_pref;
500 /* switch to a better default route
502 if (new_drp != cur_drp) {
503 rt = rtget(RIP_DEFAULT, 0);
505 /* Stop using discovered routes if they are all bad
507 if (new_drp == NULL) {
508 trace_act("turn off Router Discovery client");
512 && (rt->rt_state & RS_RDISC)) {
513 new = rt->rt_spares[0];
514 new.rts_metric = HOPCNT_INFINITY;
515 new.rts_time = now.tv_sec - GARBAGE_TIME;
516 rtchange(rt, rt->rt_state & ~RS_RDISC,
522 if (cur_drp == NULL) {
523 trace_act("turn on Router Discovery client"
525 naddr_ntoa(new_drp->dr_gate),
526 new_drp->dr_ifp->int_name);
530 trace_act("switch Router Discovery from"
531 " %s via %s to %s via %s",
532 naddr_ntoa(cur_drp->dr_gate),
533 cur_drp->dr_ifp->int_name,
534 naddr_ntoa(new_drp->dr_gate),
535 new_drp->dr_ifp->int_name);
538 memset(&new, 0, sizeof(new));
539 new.rts_ifp = new_drp->dr_ifp;
540 new.rts_gate = new_drp->dr_gate;
541 new.rts_router = new_drp->dr_gate;
542 new.rts_metric = HOPCNT_INFINITY-1;
543 new.rts_time = now.tv_sec;
545 rtchange(rt, rt->rt_state | RS_RDISC, &new, 0);
547 rtadd(RIP_DEFAULT, 0, RS_RDISC, &new);
554 /* turn RIP on or off */
555 if (!rdisc_ok || rip_interfaces > 1) {
563 /* handle a single address in an advertisement
568 n_long pref, /* signed and in network order */
569 u_short life, /* in host byte order */
570 struct interface *ifp)
572 static struct msg_limit bad_gate;
573 struct dr *drp, *new_drp;
576 if (gate == RIP_DEFAULT
577 || !check_dst(gate)) {
578 msglim(&bad_gate, from,"router %s advertising bad gateway %s",
584 /* ignore pointers to ourself and routes via unreachable networks
586 if (ifwithaddr(gate, 1, 0) != 0) {
587 trace_pkt(" discard Router Discovery Ad pointing at us");
590 if (!on_net(gate, ifp->int_net, ifp->int_mask)) {
591 trace_pkt(" discard Router Discovery Ad"
592 " toward unreachable net");
596 /* Convert preference to an unsigned value
597 * and later bias it by the metric of the interface.
599 pref = UNSIGN_PREF(ntohl(pref));
601 if (pref == 0 || life < MinMaxAdvertiseInterval) {
606 for (new_drp = NULL, drp = drs; drp < &drs[MAX_ADS]; drp++) {
607 /* accept new info for a familiar entry
609 if (drp->dr_gate == gate) {
615 continue; /* do not worry about dead ads */
617 if (drp->dr_ts == 0) {
618 new_drp = drp; /* use unused entry */
620 } else if (new_drp == NULL) {
621 /* look for an entry worse than the new one to
624 if ((!(ifp->int_state & IS_SICK)
625 && (drp->dr_ifp->int_state & IS_SICK))
626 || (pref > drp->dr_pref
627 && !((ifp->int_state ^ drp->dr_ifp->int_state)
631 } else if (new_drp->dr_ts != 0) {
632 /* look for the least valuable entry to reuse
634 if ((!(new_drp->dr_ifp->int_state & IS_SICK)
635 && (drp->dr_ifp->int_state & IS_SICK))
636 || (new_drp->dr_pref > drp->dr_pref
637 && !((new_drp->dr_ifp->int_state
638 ^ drp->dr_ifp->int_state)
644 /* forget it if all of the current entries are better */
648 new_drp->dr_ifp = ifp;
649 new_drp->dr_gate = gate;
650 new_drp->dr_ts = now.tv_sec;
651 new_drp->dr_life = life;
652 new_drp->dr_recv_pref = pref;
653 /* bias functional preference by metric of the interface */
654 new_drp->dr_pref = PREF(pref,ifp);
656 /* after hearing a good advertisement, stop asking
658 if (!(ifp->int_state & IS_SICK))
659 ifp->int_rdisc_cnt = MAX_SOLICITATIONS;
663 /* Compute the IP checksum
664 * This assumes the packet is less than 32K long.
671 int nwords = len >> 1;
673 while (nwords-- != 0)
679 /* end-around-carry */
680 sum = (sum >> 16) + (sum & 0xffff);
686 /* Send a router discovery advertisement or solicitation ICMP packet.
689 send_rdisc(union ad_u *p,
691 struct interface *ifp,
692 naddr dst, /* 0 or unicast destination */
693 int type) /* 0=unicast, 1=bcast, 2=mcast */
695 struct sockaddr_in in;
701 memset(&in, 0, sizeof(in));
702 in.sin_addr.s_addr = dst;
703 in.sin_family = AF_INET;
705 in.sin_len = sizeof(in);
707 flags = MSG_DONTROUTE;
710 case 0: /* unicast */
715 case 1: /* broadcast */
716 if (ifp->int_if_flags & IFF_POINTOPOINT) {
717 msg = "Send pt-to-pt";
718 in.sin_addr.s_addr = ifp->int_dstaddr;
720 msg = "Send broadcast";
721 in.sin_addr.s_addr = ifp->int_brdaddr;
725 case 2: /* multicast */
726 msg = "Send multicast";
727 if (ifp->int_state & IS_DUP) {
728 trace_act("abort multicast output via %s"
729 " with duplicate address",
733 if (rdisc_sock_mcast != ifp) {
734 /* select the right interface. */
736 /* Do not specify the primary interface explicitly
737 * if we have the multicast point-to-point kernel
738 * bug, since the kernel will do the wrong thing
739 * if the local address of a point-to-point link
740 * is the same as the address of an ordinary
743 if (ifp->int_addr == myaddr) {
747 tgt_mcast = ifp->int_addr;
748 if (0 > setsockopt(rdisc_sock,
749 IPPROTO_IP, IP_MULTICAST_IF,
750 &tgt_mcast, sizeof(tgt_mcast))) {
751 LOGERR("setsockopt(rdisc_sock,"
753 rdisc_sock_mcast = NULL;
756 rdisc_sock_mcast = ifp;
765 trace_rdisc(msg, ifp->int_addr, in.sin_addr.s_addr, ifp,
768 if (0 > sendto(rdisc_sock, p, p_size, flags,
769 (struct sockaddr *)&in, sizeof(in))) {
770 if (ifp == NULL || !(ifp->int_state & IS_BROKE))
771 msglog("sendto(%s%s%s): %s",
772 ifp != NULL ? ifp->int_name : "",
773 ifp != NULL ? ", " : "",
774 inet_ntoa(in.sin_addr),
782 /* Send an advertisement
785 send_adv(struct interface *ifp,
786 naddr dst, /* 0 or unicast destination */
787 int type) /* 0=unicast, 1=bcast, 2=mcast */
793 memset(&u, 0, sizeof(u.ad));
795 u.ad.icmp_type = ICMP_ROUTERADVERT;
796 u.ad.icmp_ad_num = 1;
797 u.ad.icmp_ad_asize = sizeof(u.ad.icmp_ad_info[0])/4;
799 u.ad.icmp_ad_life = stopint ? 0 : htons(ifp->int_rdisc_int*3);
801 /* Convert the configured preference to an unsigned value,
802 * bias it by the interface metric, and then send it as a
803 * signed, network byte order value.
805 pref = UNSIGN_PREF(ifp->int_rdisc_pref);
806 u.ad.icmp_ad_info[0].icmp_ad_pref = htonl(SIGN_PREF(PREF(pref, ifp)));
808 u.ad.icmp_ad_info[0].icmp_ad_addr = ifp->int_addr;
810 u.ad.icmp_cksum = in_cksum((u_short*)&u.ad, sizeof(u.ad));
812 send_rdisc(&u, sizeof(u.ad), ifp, dst, type);
816 /* Advertise for Router Discovery
821 struct interface *ifp;
826 rdisc_timer.tv_sec = now.tv_sec + NEVER;
828 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
829 if (0 != (ifp->int_state & (IS_NO_ADV_OUT | IS_BROKE)))
832 if (!timercmp(&ifp->int_rdisc_timer, &now, >)
834 send_adv(ifp, htonl(INADDR_ALLHOSTS_GROUP),
835 (ifp->int_state&IS_BCAST_RDISC) ? 1 : 2);
836 ifp->int_rdisc_cnt++;
838 intvl_random(&ifp->int_rdisc_timer,
839 (ifp->int_rdisc_int*3)/4,
841 if (ifp->int_rdisc_cnt < MAX_INITIAL_ADVERTS
842 && (ifp->int_rdisc_timer.tv_sec
843 > MAX_INITIAL_ADVERT_INTERVAL)) {
844 ifp->int_rdisc_timer.tv_sec
845 = MAX_INITIAL_ADVERT_INTERVAL;
847 timevaladd(&ifp->int_rdisc_timer, &now);
850 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
851 rdisc_timer = ifp->int_rdisc_timer;
856 /* Solicit for Router Discovery
861 struct interface *ifp;
868 rdisc_timer.tv_sec = now.tv_sec + NEVER;
870 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
871 if (0 != (ifp->int_state & (IS_NO_SOL_OUT | IS_BROKE))
872 || ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
875 if (!timercmp(&ifp->int_rdisc_timer, &now, >)) {
876 memset(&u, 0, sizeof(u.so));
877 u.so.icmp_type = ICMP_ROUTERSOLICIT;
878 u.so.icmp_cksum = in_cksum((u_short*)&u.so,
880 send_rdisc(&u, sizeof(u.so), ifp,
881 htonl(INADDR_ALLROUTERS_GROUP),
882 ((ifp->int_state&IS_BCAST_RDISC) ? 1 : 2));
884 if (++ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
887 ifp->int_rdisc_timer.tv_sec = SOLICITATION_INTERVAL;
888 ifp->int_rdisc_timer.tv_usec = 0;
889 timevaladd(&ifp->int_rdisc_timer, &now);
892 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
893 rdisc_timer = ifp->int_rdisc_timer;
898 /* check the IP header of a possible Router Discovery ICMP packet */
899 static struct interface * /* 0 if bad */
900 ck_icmp(const char *act,
902 struct interface *ifp,
910 if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
911 type = "advertisement";
912 } else if (p->icmp.icmp_type == ICMP_ROUTERSOLICIT) {
913 type = "solicitation";
918 if (p->icmp.icmp_code != 0) {
919 trace_pkt("unrecognized ICMP Router %s code=%d from %s to %s",
920 type, p->icmp.icmp_code,
921 naddr_ntoa(from), naddr_ntoa(to));
925 trace_rdisc(act, from, to, ifp, p, len);
928 trace_pkt("unknown interface for router-discovery %s"
930 type, naddr_ntoa(from), naddr_ntoa(to));
936 /* read packets from the router discovery socket
941 static struct msg_limit bad_asize, bad_len;
942 #ifdef USE_PASSIFNAME
943 static struct msg_limit bad_name;
945 struct sockaddr_in from;
946 int n, fromlen, cc, hlen;
948 #ifdef USE_PASSIFNAME
949 char ifname[IFNAMSIZ];
959 struct interface *ifp;
963 fromlen = sizeof(from);
964 cc = recvfrom(rdisc_sock, &buf, sizeof(buf), 0,
965 (struct sockaddr*)&from,
968 if (cc < 0 && errno != EWOULDBLOCK)
969 LOGERR("recvfrom(rdisc_sock)");
972 if (fromlen != sizeof(struct sockaddr_in))
973 logbad(1,"impossible recvfrom(rdisc_sock) fromlen=%d",
975 #ifdef USE_PASSIFNAME
976 if ((cc -= sizeof(buf.ifname)) < 0)
977 logbad(0,"missing USE_PASSIFNAME; only %d bytes",
978 cc+sizeof(buf.ifname));
981 hlen = buf.pkt.ip.ip_hl << 2;
982 if (cc < hlen + ICMP_MINLEN)
984 p = (union ad_u *)&buf.pkt.b[hlen];
987 #ifdef USE_PASSIFNAME
988 ifp = ifwithname(buf.ifname, 0);
990 msglim(&bad_name, from.sin_addr.s_addr,
991 "impossible rdisc if_ name %.*s",
992 IFNAMSIZ, buf.ifname);
994 /* If we could tell the interface on which a packet from
995 * address 0 arrived, we could deal with such solicitations.
997 ifp = ((from.sin_addr.s_addr == 0)
998 ? 0 : iflookup(from.sin_addr.s_addr));
1000 ifp = ck_icmp("Recv", from.sin_addr.s_addr, ifp,
1001 buf.pkt.ip.ip_dst.s_addr, p, cc);
1004 if (ifwithaddr(from.sin_addr.s_addr, 0, 0)) {
1006 "discard our own Router Discovery message");
1010 switch (p->icmp.icmp_type) {
1011 case ICMP_ROUTERADVERT:
1012 if (p->ad.icmp_ad_asize*4
1013 < (int)sizeof(p->ad.icmp_ad_info[0])) {
1014 msglim(&bad_asize, from.sin_addr.s_addr,
1015 "intolerable rdisc address size=%d",
1016 p->ad.icmp_ad_asize);
1019 if (p->ad.icmp_ad_num == 0) {
1020 trace_pkt(" empty?");
1023 if (cc != (int)(sizeof(p->ad)
1024 - sizeof(p->ad.icmp_ad_info)
1025 + (p->ad.icmp_ad_num
1026 * sizeof(p->ad.icmp_ad_info[0])))) {
1027 msglim(&bad_len, from.sin_addr.s_addr,
1028 "rdisc length %d does not match ad_num"
1029 " %d", cc, p->ad.icmp_ad_num);
1034 if (ifp->int_state & IS_NO_ADV_IN)
1037 wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
1038 for (n = 0; n < p->ad.icmp_ad_num; n++) {
1039 parse_ad(from.sin_addr.s_addr,
1041 ntohs(p->ad.icmp_ad_life),
1043 wp += p->ad.icmp_ad_asize;
1048 case ICMP_ROUTERSOLICIT:
1051 if (ifp->int_state & IS_NO_ADV_OUT)
1057 * We should handle messages from address 0.
1060 /* Respond with a point-to-point advertisement */
1061 send_adv(ifp, from.sin_addr.s_addr, 0);