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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
14 * must display the following acknowledgment:
15 * This product includes software developed by the University of
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18 * may be used to endorse or promote products derived from this software
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23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * $FreeBSD: src/sbin/routed/rdisc.c,v 1.5.2.1 2000/08/14 17:00:04 sheldonh Exp $
34 * $DragonFly: src/sbin/routed/rdisc.c,v 1.2 2003/06/17 04:27:34 dillon Exp $
38 #include <netinet/in_systm.h>
39 #include <netinet/ip.h>
40 #include <netinet/ip_icmp.h>
42 #if !defined(sgi) && !defined(__NetBSD__)
43 static char sccsid[] __attribute__((unused)) = "@(#)rdisc.c 8.1 (Berkeley) x/y/95";
44 #elif defined(__NetBSD__)
47 #ident "$FreeBSD: src/sbin/routed/rdisc.c,v 1.5.2.1 2000/08/14 17:00:04 sheldonh Exp $"
49 /* router advertisement ICMP packet */
51 u_int8_t icmp_type; /* type of message */
52 u_int8_t icmp_code; /* type sub code */
53 u_int16_t icmp_cksum; /* ones complement cksum of struct */
54 u_int8_t icmp_ad_num; /* # of following router addresses */
55 u_int8_t icmp_ad_asize; /* 2--words in each advertisement */
56 u_int16_t icmp_ad_life; /* seconds of validity */
63 /* router solicitation ICMP packet */
65 u_int8_t icmp_type; /* type of message */
66 u_int8_t icmp_code; /* type sub code */
67 u_int16_t icmp_cksum; /* ones complement cksum of struct */
78 int rdisc_sock = -1; /* router-discovery raw socket */
79 struct interface *rdisc_sock_mcast; /* current multicast interface */
81 struct timeval rdisc_timer;
82 int rdisc_ok; /* using solicited route */
85 #define MAX_ADS 16 /* at least one per interface */
86 struct dr { /* accumulated advertisements */
87 struct interface *dr_ifp;
88 naddr dr_gate; /* gateway */
89 time_t dr_ts; /* when received */
90 time_t dr_life; /* lifetime in host byte order */
91 n_long dr_recv_pref; /* received but biased preference */
92 n_long dr_pref; /* preference adjusted by metric */
93 } *cur_drp, drs[MAX_ADS];
95 /* convert between signed, balanced around zero,
96 * and unsigned zero-based preferences */
97 #define SIGN_PREF(p) ((p) ^ MIN_PreferenceLevel)
98 #define UNSIGN_PREF(p) SIGN_PREF(p)
99 /* adjust unsigned preference by interface metric,
100 * without driving it to infinity */
101 #define PREF(p, ifp) ((int)(p) <= (ifp)->int_metric ? ((p) != 0 ? 1 : 0) \
102 : (p) - ((ifp)->int_metric))
104 static void rdisc_sort(void);
107 /* dump an ICMP Router Discovery Advertisement Message
110 trace_rdisc(const char *act,
113 struct interface *ifp,
121 if (!TRACEPACKETS || ftrace == 0)
126 if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
127 (void)fprintf(ftrace, "%s Router Ad"
128 " from %s to %s via %s life=%d\n",
129 act, naddr_ntoa(from), naddr_ntoa(to),
130 ifp ? ifp->int_name : "?",
131 ntohs(p->ad.icmp_ad_life));
135 wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
136 lim = &wp[(len - sizeof(p->ad)) / sizeof(*wp)];
137 for (i = 0; i < p->ad.icmp_ad_num && wp <= lim; i++) {
138 (void)fprintf(ftrace, "\t%s preference=%d",
139 naddr_ntoa(wp[0]), (int)ntohl(wp[1]));
140 wp += p->ad.icmp_ad_asize;
142 (void)fputc('\n',ftrace);
145 trace_act("%s Router Solic. from %s to %s via %s value=%#x",
146 act, naddr_ntoa(from), naddr_ntoa(to),
147 ifp ? ifp->int_name : "?",
148 (int)ntohl(p->so.icmp_so_rsvd));
152 /* prepare Router Discovery socket.
157 if (rdisc_sock < 0) {
158 rdisc_sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
160 BADERR(1,"rdisc_sock = socket()");
161 fix_sock(rdisc_sock,"rdisc_sock");
167 /* Pick multicast group for router-discovery socket
170 set_rdisc_mg(struct interface *ifp,
171 int on) /* 0=turn it off */
175 if (rdisc_sock < 0) {
176 /* Create the raw socket so that we can hear at least
177 * broadcast router discovery packets.
179 if ((ifp->int_state & IS_NO_RDISC) == IS_NO_RDISC
185 if (!(ifp->int_if_flags & IFF_MULTICAST)) {
186 ifp->int_state &= ~(IS_ALL_HOSTS | IS_ALL_ROUTERS);
191 if (ifp->int_if_flags & IFF_POINTOPOINT)
194 memset(&m, 0, sizeof(m));
195 m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
199 || (ifp->int_state & IS_NO_ADV_IN)
201 /* stop listening to advertisements
203 if (ifp->int_state & IS_ALL_HOSTS) {
204 m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
205 if (setsockopt(rdisc_sock, IPPROTO_IP,
208 LOGERR("IP_DROP_MEMBERSHIP ALLHOSTS");
209 ifp->int_state &= ~IS_ALL_HOSTS;
212 } else if (!(ifp->int_state & IS_ALL_HOSTS)) {
213 /* start listening to advertisements
215 m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
216 if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
217 &m, sizeof(m)) < 0) {
218 LOGERR("IP_ADD_MEMBERSHIP ALLHOSTS");
220 ifp->int_state |= IS_ALL_HOSTS;
225 || (ifp->int_state & IS_NO_ADV_OUT)
227 /* stop listening to solicitations
229 if (ifp->int_state & IS_ALL_ROUTERS) {
230 m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
231 if (setsockopt(rdisc_sock, IPPROTO_IP,
234 LOGERR("IP_DROP_MEMBERSHIP ALLROUTERS");
235 ifp->int_state &= ~IS_ALL_ROUTERS;
238 } else if (!(ifp->int_state & IS_ALL_ROUTERS)) {
239 /* start hearing solicitations
241 m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
242 if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
243 &m, sizeof(m)) < 0) {
244 LOGERR("IP_ADD_MEMBERSHIP ALLROUTERS");
246 ifp->int_state |= IS_ALL_ROUTERS;
252 /* start supplying routes
257 struct interface *ifp;
263 trace_act("start supplying routes");
265 /* Forget discovered routes.
267 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
268 drp->dr_recv_pref = 0;
276 /* Do not start advertising until we have heard some RIP routes */
277 LIM_SEC(rdisc_timer, now.tv_sec+MIN_WAITTIME);
279 /* Switch router discovery multicast groups from soliciting
282 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
283 if (ifp->int_state & IS_BROKE)
285 ifp->int_rdisc_cnt = 0;
286 ifp->int_rdisc_timer.tv_usec = rdisc_timer.tv_usec;
287 ifp->int_rdisc_timer.tv_sec = now.tv_sec+MIN_WAITTIME;
288 set_rdisc_mg(ifp, 1);
291 /* get rid of any redirects */
296 /* age discovered routes and find the best one
299 rdisc_age(naddr bad_gate)
305 /* If only advertising, then do only that. */
307 /* If switching from client to server, get rid of old
316 /* If we are being told about a bad router,
317 * then age the discovered default route, and if there is
318 * no alternative, solicit a replacement.
321 /* Look for the bad discovered default route.
322 * Age it and note its interface.
324 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
328 /* When we find the bad router, then age the route
329 * to at most SUPPLY_INTERVAL.
330 * This is contrary to RFC 1256, but defends against
333 if (drp->dr_gate == bad_gate) {
334 sec = (now.tv_sec - drp->dr_life
336 if (drp->dr_ts > sec) {
337 trace_act("age 0.0.0.0 --> %s via %s",
338 naddr_ntoa(drp->dr_gate),
339 drp->dr_ifp->int_name);
350 /* Delete old redirected routes to keep the kernel table small,
351 * and to prevent black holes. Check that the kernel table
352 * matches the daemon table (i.e. has the default route).
353 * But only if RIP is not running and we are not dealing with
354 * a bad gateway, since otherwise age() will be called.
356 if (rip_sock < 0 && bad_gate == 0)
361 /* Zap all routes discovered via an interface that has gone bad
362 * This should only be called when !(ifp->int_state & IS_ALIAS)
365 if_bad_rdisc(struct interface *ifp)
369 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
370 if (drp->dr_ifp != ifp)
372 drp->dr_recv_pref = 0;
377 /* make a note to re-solicit, turn RIP on or off, etc. */
378 rdisc_timer.tv_sec = 0;
382 /* mark an interface ok for router discovering.
385 if_ok_rdisc(struct interface *ifp)
387 set_rdisc_mg(ifp, 1);
389 ifp->int_rdisc_cnt = 0;
390 ifp->int_rdisc_timer.tv_sec = now.tv_sec + (supplier
392 : MAX_SOLICITATION_DELAY);
393 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
394 rdisc_timer = ifp->int_rdisc_timer;
398 /* get rid of a dead discovered router
401 del_rdisc(struct dr *drp)
403 struct interface *ifp;
408 del_redirects(gate = drp->dr_gate, 0);
413 /* Count the other discovered routes on the interface.
417 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
419 && drp->dr_ifp == ifp)
423 /* If that was the last good discovered router on the interface,
424 * then solicit a new one.
425 * This is contrary to RFC 1256, but defends against black holes.
428 trace_act("discovered router %s via %s"
429 " is bad--have %d remaining",
430 naddr_ntoa(gate), ifp->int_name, i);
431 } else if (ifp->int_rdisc_cnt >= MAX_SOLICITATIONS) {
432 trace_act("last discovered router %s via %s"
433 " is bad--re-solicit",
434 naddr_ntoa(gate), ifp->int_name);
435 ifp->int_rdisc_cnt = 0;
436 ifp->int_rdisc_timer.tv_sec = 0;
439 trace_act("last discovered router %s via %s"
440 " is bad--wait to solicit",
441 naddr_ntoa(gate), ifp->int_name);
446 /* Find the best discovered route,
447 * and discard stale routers.
452 struct dr *drp, *new_drp;
455 struct interface *ifp;
460 /* Find the best discovered route.
463 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
468 /* Get rid of expired discovered routers.
470 if (drp->dr_ts + drp->dr_life <= now.tv_sec) {
475 LIM_SEC(rdisc_timer, drp->dr_ts+drp->dr_life+1);
477 /* Update preference with possibly changed interface
480 drp->dr_pref = PREF(drp->dr_recv_pref, ifp);
482 /* Prefer the current route to prevent thrashing.
483 * Prefer shorter lifetimes to speed the detection of
485 * Avoid sick interfaces.
488 || (!((new_st ^ drp->dr_ifp->int_state) & IS_SICK)
489 && (new_pref < drp->dr_pref
490 || (new_pref == drp->dr_pref
492 || (new_drp != cur_drp
493 && new_drp->dr_life > drp->dr_life)))))
494 || ((new_st & IS_SICK)
495 && !(drp->dr_ifp->int_state & IS_SICK))) {
497 new_st = drp->dr_ifp->int_state;
498 new_pref = drp->dr_pref;
502 /* switch to a better default route
504 if (new_drp != cur_drp) {
505 rt = rtget(RIP_DEFAULT, 0);
507 /* Stop using discovered routes if they are all bad
510 trace_act("turn off Router Discovery client");
514 && (rt->rt_state & RS_RDISC)) {
515 new = rt->rt_spares[0];
516 new.rts_metric = HOPCNT_INFINITY;
517 new.rts_time = now.tv_sec - GARBAGE_TIME;
518 rtchange(rt, rt->rt_state & ~RS_RDISC,
525 trace_act("turn on Router Discovery client"
527 naddr_ntoa(new_drp->dr_gate),
528 new_drp->dr_ifp->int_name);
532 trace_act("switch Router Discovery from"
533 " %s via %s to %s via %s",
534 naddr_ntoa(cur_drp->dr_gate),
535 cur_drp->dr_ifp->int_name,
536 naddr_ntoa(new_drp->dr_gate),
537 new_drp->dr_ifp->int_name);
540 memset(&new, 0, sizeof(new));
541 new.rts_ifp = new_drp->dr_ifp;
542 new.rts_gate = new_drp->dr_gate;
543 new.rts_router = new_drp->dr_gate;
544 new.rts_metric = HOPCNT_INFINITY-1;
545 new.rts_time = now.tv_sec;
547 rtchange(rt, rt->rt_state | RS_RDISC, &new, 0);
549 rtadd(RIP_DEFAULT, 0, RS_RDISC, &new);
556 /* turn RIP on or off */
557 if (!rdisc_ok || rip_interfaces > 1) {
565 /* handle a single address in an advertisement
570 n_long pref, /* signed and in network order */
571 u_short life, /* in host byte order */
572 struct interface *ifp)
574 static struct msg_limit bad_gate;
575 struct dr *drp, *new_drp;
578 if (gate == RIP_DEFAULT
579 || !check_dst(gate)) {
580 msglim(&bad_gate, from,"router %s advertising bad gateway %s",
586 /* ignore pointers to ourself and routes via unreachable networks
588 if (ifwithaddr(gate, 1, 0) != 0) {
589 trace_pkt(" discard Router Discovery Ad pointing at us");
592 if (!on_net(gate, ifp->int_net, ifp->int_mask)) {
593 trace_pkt(" discard Router Discovery Ad"
594 " toward unreachable net");
598 /* Convert preference to an unsigned value
599 * and later bias it by the metric of the interface.
601 pref = UNSIGN_PREF(ntohl(pref));
603 if (pref == 0 || life < MinMaxAdvertiseInterval) {
608 for (new_drp = 0, drp = drs; drp < &drs[MAX_ADS]; drp++) {
609 /* accept new info for a familiar entry
611 if (drp->dr_gate == gate) {
617 continue; /* do not worry about dead ads */
619 if (drp->dr_ts == 0) {
620 new_drp = drp; /* use unused entry */
622 } else if (new_drp == 0) {
623 /* look for an entry worse than the new one to
626 if ((!(ifp->int_state & IS_SICK)
627 && (drp->dr_ifp->int_state & IS_SICK))
628 || (pref > drp->dr_pref
629 && !((ifp->int_state ^ drp->dr_ifp->int_state)
633 } else if (new_drp->dr_ts != 0) {
634 /* look for the least valuable entry to reuse
636 if ((!(new_drp->dr_ifp->int_state & IS_SICK)
637 && (drp->dr_ifp->int_state & IS_SICK))
638 || (new_drp->dr_pref > drp->dr_pref
639 && !((new_drp->dr_ifp->int_state
640 ^ drp->dr_ifp->int_state)
646 /* forget it if all of the current entries are better */
650 new_drp->dr_ifp = ifp;
651 new_drp->dr_gate = gate;
652 new_drp->dr_ts = now.tv_sec;
653 new_drp->dr_life = life;
654 new_drp->dr_recv_pref = pref;
655 /* bias functional preference by metric of the interface */
656 new_drp->dr_pref = PREF(pref,ifp);
658 /* after hearing a good advertisement, stop asking
660 if (!(ifp->int_state & IS_SICK))
661 ifp->int_rdisc_cnt = MAX_SOLICITATIONS;
665 /* Compute the IP checksum
666 * This assumes the packet is less than 32K long.
673 int nwords = len >> 1;
675 while (nwords-- != 0)
681 /* end-around-carry */
682 sum = (sum >> 16) + (sum & 0xffff);
688 /* Send a router discovery advertisement or solicitation ICMP packet.
691 send_rdisc(union ad_u *p,
693 struct interface *ifp,
694 naddr dst, /* 0 or unicast destination */
695 int type) /* 0=unicast, 1=bcast, 2=mcast */
697 struct sockaddr_in sin;
703 memset(&sin, 0, sizeof(sin));
704 sin.sin_addr.s_addr = dst;
705 sin.sin_family = AF_INET;
707 sin.sin_len = sizeof(sin);
709 flags = MSG_DONTROUTE;
712 case 0: /* unicast */
717 case 1: /* broadcast */
718 if (ifp->int_if_flags & IFF_POINTOPOINT) {
719 msg = "Send pt-to-pt";
720 sin.sin_addr.s_addr = ifp->int_dstaddr;
722 msg = "Send broadcast";
723 sin.sin_addr.s_addr = ifp->int_brdaddr;
727 case 2: /* multicast */
728 msg = "Send multicast";
729 if (ifp->int_state & IS_DUP) {
730 trace_act("abort multicast output via %s"
731 " with duplicate address",
735 if (rdisc_sock_mcast != ifp) {
736 /* select the right interface. */
738 /* Do not specify the primary interface explicitly
739 * if we have the multicast point-to-point kernel
740 * bug, since the kernel will do the wrong thing
741 * if the local address of a point-to-point link
742 * is the same as the address of an ordinary
745 if (ifp->int_addr == myaddr) {
749 tgt_mcast = ifp->int_addr;
750 if (0 > setsockopt(rdisc_sock,
751 IPPROTO_IP, IP_MULTICAST_IF,
752 &tgt_mcast, sizeof(tgt_mcast))) {
753 LOGERR("setsockopt(rdisc_sock,"
755 rdisc_sock_mcast = 0;
758 rdisc_sock_mcast = ifp;
767 trace_rdisc(msg, ifp->int_addr, sin.sin_addr.s_addr, ifp,
770 if (0 > sendto(rdisc_sock, p, p_size, flags,
771 (struct sockaddr *)&sin, sizeof(sin))) {
772 if (ifp == 0 || !(ifp->int_state & IS_BROKE))
773 msglog("sendto(%s%s%s): %s",
774 ifp != 0 ? ifp->int_name : "",
775 ifp != 0 ? ", " : "",
776 inet_ntoa(sin.sin_addr),
784 /* Send an advertisement
787 send_adv(struct interface *ifp,
788 naddr dst, /* 0 or unicast destination */
789 int type) /* 0=unicast, 1=bcast, 2=mcast */
795 memset(&u, 0, sizeof(u.ad));
797 u.ad.icmp_type = ICMP_ROUTERADVERT;
798 u.ad.icmp_ad_num = 1;
799 u.ad.icmp_ad_asize = sizeof(u.ad.icmp_ad_info[0])/4;
801 u.ad.icmp_ad_life = stopint ? 0 : htons(ifp->int_rdisc_int*3);
803 /* Convert the configured preference to an unsigned value,
804 * bias it by the interface metric, and then send it as a
805 * signed, network byte order value.
807 pref = UNSIGN_PREF(ifp->int_rdisc_pref);
808 u.ad.icmp_ad_info[0].icmp_ad_pref = htonl(SIGN_PREF(PREF(pref, ifp)));
810 u.ad.icmp_ad_info[0].icmp_ad_addr = ifp->int_addr;
812 u.ad.icmp_cksum = in_cksum((u_short*)&u.ad, sizeof(u.ad));
814 send_rdisc(&u, sizeof(u.ad), ifp, dst, type);
818 /* Advertise for Router Discovery
823 struct interface *ifp;
828 rdisc_timer.tv_sec = now.tv_sec + NEVER;
830 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
831 if (0 != (ifp->int_state & (IS_NO_ADV_OUT | IS_BROKE)))
834 if (!timercmp(&ifp->int_rdisc_timer, &now, >)
836 send_adv(ifp, htonl(INADDR_ALLHOSTS_GROUP),
837 (ifp->int_state&IS_BCAST_RDISC) ? 1 : 2);
838 ifp->int_rdisc_cnt++;
840 intvl_random(&ifp->int_rdisc_timer,
841 (ifp->int_rdisc_int*3)/4,
843 if (ifp->int_rdisc_cnt < MAX_INITIAL_ADVERTS
844 && (ifp->int_rdisc_timer.tv_sec
845 > MAX_INITIAL_ADVERT_INTERVAL)) {
846 ifp->int_rdisc_timer.tv_sec
847 = MAX_INITIAL_ADVERT_INTERVAL;
849 timevaladd(&ifp->int_rdisc_timer, &now);
852 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
853 rdisc_timer = ifp->int_rdisc_timer;
858 /* Solicit for Router Discovery
863 struct interface *ifp;
870 rdisc_timer.tv_sec = now.tv_sec + NEVER;
872 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
873 if (0 != (ifp->int_state & (IS_NO_SOL_OUT | IS_BROKE))
874 || ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
877 if (!timercmp(&ifp->int_rdisc_timer, &now, >)) {
878 memset(&u, 0, sizeof(u.so));
879 u.so.icmp_type = ICMP_ROUTERSOLICIT;
880 u.so.icmp_cksum = in_cksum((u_short*)&u.so,
882 send_rdisc(&u, sizeof(u.so), ifp,
883 htonl(INADDR_ALLROUTERS_GROUP),
884 ((ifp->int_state&IS_BCAST_RDISC) ? 1 : 2));
886 if (++ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
889 ifp->int_rdisc_timer.tv_sec = SOLICITATION_INTERVAL;
890 ifp->int_rdisc_timer.tv_usec = 0;
891 timevaladd(&ifp->int_rdisc_timer, &now);
894 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
895 rdisc_timer = ifp->int_rdisc_timer;
900 /* check the IP header of a possible Router Discovery ICMP packet */
901 static struct interface * /* 0 if bad */
902 ck_icmp(const char *act,
904 struct interface *ifp,
912 if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
913 type = "advertisement";
914 } else if (p->icmp.icmp_type == ICMP_ROUTERSOLICIT) {
915 type = "solicitation";
920 if (p->icmp.icmp_code != 0) {
921 trace_pkt("unrecognized ICMP Router %s code=%d from %s to %s",
922 type, p->icmp.icmp_code,
923 naddr_ntoa(from), naddr_ntoa(to));
927 trace_rdisc(act, from, to, ifp, p, len);
930 trace_pkt("unknown interface for router-discovery %s"
932 type, naddr_ntoa(from), naddr_ntoa(to));
938 /* read packets from the router discovery socket
943 static struct msg_limit bad_asize, bad_len;
944 #ifdef USE_PASSIFNAME
945 static struct msg_limit bad_name;
947 struct sockaddr_in from;
948 int n, fromlen, cc, hlen;
950 #ifdef USE_PASSIFNAME
951 char ifname[IFNAMSIZ];
961 struct interface *ifp;
965 fromlen = sizeof(from);
966 cc = recvfrom(rdisc_sock, &buf, sizeof(buf), 0,
967 (struct sockaddr*)&from,
970 if (cc < 0 && errno != EWOULDBLOCK)
971 LOGERR("recvfrom(rdisc_sock)");
974 if (fromlen != sizeof(struct sockaddr_in))
975 logbad(1,"impossible recvfrom(rdisc_sock) fromlen=%d",
977 #ifdef USE_PASSIFNAME
978 if ((cc -= sizeof(buf.ifname)) < 0)
979 logbad(0,"missing USE_PASSIFNAME; only %d bytes",
980 cc+sizeof(buf.ifname));
983 hlen = buf.pkt.ip.ip_hl << 2;
984 if (cc < hlen + ICMP_MINLEN)
986 p = (union ad_u *)&buf.pkt.b[hlen];
989 #ifdef USE_PASSIFNAME
990 ifp = ifwithname(buf.ifname, 0);
992 msglim(&bad_name, from.sin_addr.s_addr,
993 "impossible rdisc if_ name %.*s",
994 IFNAMSIZ, buf.ifname);
996 /* If we could tell the interface on which a packet from
997 * address 0 arrived, we could deal with such solicitations.
999 ifp = ((from.sin_addr.s_addr == 0)
1000 ? 0 : iflookup(from.sin_addr.s_addr));
1002 ifp = ck_icmp("Recv", from.sin_addr.s_addr, ifp,
1003 buf.pkt.ip.ip_dst.s_addr, p, cc);
1006 if (ifwithaddr(from.sin_addr.s_addr, 0, 0)) {
1008 "discard our own Router Discovery message");
1012 switch (p->icmp.icmp_type) {
1013 case ICMP_ROUTERADVERT:
1014 if (p->ad.icmp_ad_asize*4
1015 < (int)sizeof(p->ad.icmp_ad_info[0])) {
1016 msglim(&bad_asize, from.sin_addr.s_addr,
1017 "intolerable rdisc address size=%d",
1018 p->ad.icmp_ad_asize);
1021 if (p->ad.icmp_ad_num == 0) {
1022 trace_pkt(" empty?");
1025 if (cc != (int)(sizeof(p->ad)
1026 - sizeof(p->ad.icmp_ad_info)
1027 + (p->ad.icmp_ad_num
1028 * sizeof(p->ad.icmp_ad_info[0])))) {
1029 msglim(&bad_len, from.sin_addr.s_addr,
1030 "rdisc length %d does not match ad_num"
1031 " %d", cc, p->ad.icmp_ad_num);
1036 if (ifp->int_state & IS_NO_ADV_IN)
1039 wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
1040 for (n = 0; n < p->ad.icmp_ad_num; n++) {
1041 parse_ad(from.sin_addr.s_addr,
1043 ntohs(p->ad.icmp_ad_life),
1045 wp += p->ad.icmp_ad_asize;
1050 case ICMP_ROUTERSOLICIT:
1053 if (ifp->int_state & IS_NO_ADV_OUT)
1059 * We should handle messages from address 0.
1062 /* Respond with a point-to-point advertisement */
1063 send_adv(ifp, from.sin_addr.s_addr, 0);