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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
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12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)rdisc.c 8.1 (Berkeley) x/y/95
30 * $FreeBSD: src/sbin/routed/rdisc.c,v 1.5.2.1 2000/08/14 17:00:04 sheldonh Exp $
34 #include <netinet/in_systm.h>
35 #include <netinet/ip.h>
36 #include <netinet/ip_icmp.h>
38 /* router advertisement ICMP packet */
40 u_int8_t icmp_type
; /* type of message */
41 u_int8_t icmp_code
; /* type sub code */
42 u_int16_t icmp_cksum
; /* ones complement cksum of struct */
43 u_int8_t icmp_ad_num
; /* # of following router addresses */
44 u_int8_t icmp_ad_asize
; /* 2--words in each advertisement */
45 u_int16_t icmp_ad_life
; /* seconds of validity */
52 /* router solicitation ICMP packet */
54 u_int8_t icmp_type
; /* type of message */
55 u_int8_t icmp_code
; /* type sub code */
56 u_int16_t icmp_cksum
; /* ones complement cksum of struct */
67 int rdisc_sock
= -1; /* router-discovery raw socket */
68 struct interface
*rdisc_sock_mcast
; /* current multicast interface */
70 struct timeval rdisc_timer
;
71 int rdisc_ok
; /* using solicited route */
74 #define MAX_ADS 16 /* at least one per interface */
75 struct dr
{ /* accumulated advertisements */
76 struct interface
*dr_ifp
;
77 naddr dr_gate
; /* gateway */
78 time_t dr_ts
; /* when received */
79 time_t dr_life
; /* lifetime in host byte order */
80 n_long dr_recv_pref
; /* received but biased preference */
81 n_long dr_pref
; /* preference adjusted by metric */
82 } *cur_drp
, drs
[MAX_ADS
];
84 /* convert between signed, balanced around zero,
85 * and unsigned zero-based preferences */
86 #define SIGN_PREF(p) ((p) ^ MIN_PreferenceLevel)
87 #define UNSIGN_PREF(p) SIGN_PREF(p)
88 /* adjust unsigned preference by interface metric,
89 * without driving it to infinity */
90 #define PREF(p, ifp) ((int)(p) <= (ifp)->int_metric ? ((p) != 0 ? 1 : 0) \
91 : (p) - ((ifp)->int_metric))
93 static void rdisc_sort(void);
96 /* dump an ICMP Router Discovery Advertisement Message
99 trace_rdisc(const char *act
,
102 struct interface
*ifp
,
110 if (!TRACEPACKETS
|| ftrace
== 0)
115 if (p
->icmp
.icmp_type
== ICMP_ROUTERADVERT
) {
116 fprintf(ftrace
, "%s Router Ad"
117 " from %s to %s via %s life=%d\n",
118 act
, naddr_ntoa(from
), naddr_ntoa(to
),
119 ifp
? ifp
->int_name
: "?",
120 ntohs(p
->ad
.icmp_ad_life
));
124 wp
= &p
->ad
.icmp_ad_info
[0].icmp_ad_addr
;
125 lim
= &wp
[(len
- sizeof(p
->ad
)) / sizeof(*wp
)];
126 for (i
= 0; i
< p
->ad
.icmp_ad_num
&& wp
<= lim
; i
++) {
127 fprintf(ftrace
, "\t%s preference=%d",
128 naddr_ntoa(wp
[0]), (int)ntohl(wp
[1]));
129 wp
+= p
->ad
.icmp_ad_asize
;
134 trace_act("%s Router Solic. from %s to %s via %s value=%#x",
135 act
, naddr_ntoa(from
), naddr_ntoa(to
),
136 ifp
? ifp
->int_name
: "?",
137 (int)ntohl(p
->so
.icmp_so_rsvd
));
141 /* prepare Router Discovery socket.
146 if (rdisc_sock
< 0) {
147 rdisc_sock
= socket(AF_INET
, SOCK_RAW
, IPPROTO_ICMP
);
149 BADERR(1,"rdisc_sock = socket()");
150 fix_sock(rdisc_sock
,"rdisc_sock");
156 /* Pick multicast group for router-discovery socket
159 set_rdisc_mg(struct interface
*ifp
,
160 int on
) /* 0=turn it off */
164 if (rdisc_sock
< 0) {
165 /* Create the raw socket so that we can hear at least
166 * broadcast router discovery packets.
168 if ((ifp
->int_state
& IS_NO_RDISC
) == IS_NO_RDISC
174 if (!(ifp
->int_if_flags
& IFF_MULTICAST
)) {
175 ifp
->int_state
&= ~(IS_ALL_HOSTS
| IS_ALL_ROUTERS
);
180 if (ifp
->int_if_flags
& IFF_POINTOPOINT
)
183 memset(&m
, 0, sizeof(m
));
184 m
.imr_interface
.s_addr
= ((ifp
->int_if_flags
& IFF_POINTOPOINT
)
188 || (ifp
->int_state
& IS_NO_ADV_IN
)
190 /* stop listening to advertisements
192 if (ifp
->int_state
& IS_ALL_HOSTS
) {
193 m
.imr_multiaddr
.s_addr
= htonl(INADDR_ALLHOSTS_GROUP
);
194 if (setsockopt(rdisc_sock
, IPPROTO_IP
,
197 LOGERR("IP_DROP_MEMBERSHIP ALLHOSTS");
198 ifp
->int_state
&= ~IS_ALL_HOSTS
;
201 } else if (!(ifp
->int_state
& IS_ALL_HOSTS
)) {
202 /* start listening to advertisements
204 m
.imr_multiaddr
.s_addr
= htonl(INADDR_ALLHOSTS_GROUP
);
205 if (setsockopt(rdisc_sock
, IPPROTO_IP
, IP_ADD_MEMBERSHIP
,
206 &m
, sizeof(m
)) < 0) {
207 LOGERR("IP_ADD_MEMBERSHIP ALLHOSTS");
209 ifp
->int_state
|= IS_ALL_HOSTS
;
214 || (ifp
->int_state
& IS_NO_ADV_OUT
)
216 /* stop listening to solicitations
218 if (ifp
->int_state
& IS_ALL_ROUTERS
) {
219 m
.imr_multiaddr
.s_addr
=htonl(INADDR_ALLROUTERS_GROUP
);
220 if (setsockopt(rdisc_sock
, IPPROTO_IP
,
223 LOGERR("IP_DROP_MEMBERSHIP ALLROUTERS");
224 ifp
->int_state
&= ~IS_ALL_ROUTERS
;
227 } else if (!(ifp
->int_state
& IS_ALL_ROUTERS
)) {
228 /* start hearing solicitations
230 m
.imr_multiaddr
.s_addr
=htonl(INADDR_ALLROUTERS_GROUP
);
231 if (setsockopt(rdisc_sock
, IPPROTO_IP
, IP_ADD_MEMBERSHIP
,
232 &m
, sizeof(m
)) < 0) {
233 LOGERR("IP_ADD_MEMBERSHIP ALLROUTERS");
235 ifp
->int_state
|= IS_ALL_ROUTERS
;
241 /* start supplying routes
246 struct interface
*ifp
;
252 trace_act("start supplying routes");
254 /* Forget discovered routes.
256 for (drp
= drs
; drp
< &drs
[MAX_ADS
]; drp
++) {
257 drp
->dr_recv_pref
= 0;
265 /* Do not start advertising until we have heard some RIP routes */
266 LIM_SEC(rdisc_timer
, now
.tv_sec
+MIN_WAITTIME
);
268 /* Switch router discovery multicast groups from soliciting
271 for (ifp
= ifnet
; ifp
; ifp
= ifp
->int_next
) {
272 if (ifp
->int_state
& IS_BROKE
)
274 ifp
->int_rdisc_cnt
= 0;
275 ifp
->int_rdisc_timer
.tv_usec
= rdisc_timer
.tv_usec
;
276 ifp
->int_rdisc_timer
.tv_sec
= now
.tv_sec
+MIN_WAITTIME
;
277 set_rdisc_mg(ifp
, 1);
280 /* get rid of any redirects */
285 /* age discovered routes and find the best one
288 rdisc_age(naddr bad_gate
)
294 /* If only advertising, then do only that. */
296 /* If switching from client to server, get rid of old
305 /* If we are being told about a bad router,
306 * then age the discovered default route, and if there is
307 * no alternative, solicit a replacement.
310 /* Look for the bad discovered default route.
311 * Age it and note its interface.
313 for (drp
= drs
; drp
< &drs
[MAX_ADS
]; drp
++) {
317 /* When we find the bad router, then age the route
318 * to at most SUPPLY_INTERVAL.
319 * This is contrary to RFC 1256, but defends against
322 if (drp
->dr_gate
== bad_gate
) {
323 sec
= (now
.tv_sec
- drp
->dr_life
325 if (drp
->dr_ts
> sec
) {
326 trace_act("age 0.0.0.0 --> %s via %s",
327 naddr_ntoa(drp
->dr_gate
),
328 drp
->dr_ifp
->int_name
);
339 /* Delete old redirected routes to keep the kernel table small,
340 * and to prevent black holes. Check that the kernel table
341 * matches the daemon table (i.e. has the default route).
342 * But only if RIP is not running and we are not dealing with
343 * a bad gateway, since otherwise age() will be called.
345 if (rip_sock
< 0 && bad_gate
== 0)
350 /* Zap all routes discovered via an interface that has gone bad
351 * This should only be called when !(ifp->int_state & IS_ALIAS)
354 if_bad_rdisc(struct interface
*ifp
)
358 for (drp
= drs
; drp
< &drs
[MAX_ADS
]; drp
++) {
359 if (drp
->dr_ifp
!= ifp
)
361 drp
->dr_recv_pref
= 0;
366 /* make a note to re-solicit, turn RIP on or off, etc. */
367 rdisc_timer
.tv_sec
= 0;
371 /* mark an interface ok for router discovering.
374 if_ok_rdisc(struct interface
*ifp
)
376 set_rdisc_mg(ifp
, 1);
378 ifp
->int_rdisc_cnt
= 0;
379 ifp
->int_rdisc_timer
.tv_sec
= now
.tv_sec
+ (supplier
381 : MAX_SOLICITATION_DELAY
);
382 if (timercmp(&rdisc_timer
, &ifp
->int_rdisc_timer
, >))
383 rdisc_timer
= ifp
->int_rdisc_timer
;
387 /* get rid of a dead discovered router
390 del_rdisc(struct dr
*drp
)
392 struct interface
*ifp
;
397 del_redirects(gate
= drp
->dr_gate
, 0);
402 /* Count the other discovered routes on the interface.
406 for (drp
= drs
; drp
< &drs
[MAX_ADS
]; drp
++) {
408 && drp
->dr_ifp
== ifp
)
412 /* If that was the last good discovered router on the interface,
413 * then solicit a new one.
414 * This is contrary to RFC 1256, but defends against black holes.
417 trace_act("discovered router %s via %s"
418 " is bad--have %d remaining",
419 naddr_ntoa(gate
), ifp
->int_name
, i
);
420 } else if (ifp
->int_rdisc_cnt
>= MAX_SOLICITATIONS
) {
421 trace_act("last discovered router %s via %s"
422 " is bad--re-solicit",
423 naddr_ntoa(gate
), ifp
->int_name
);
424 ifp
->int_rdisc_cnt
= 0;
425 ifp
->int_rdisc_timer
.tv_sec
= 0;
428 trace_act("last discovered router %s via %s"
429 " is bad--wait to solicit",
430 naddr_ntoa(gate
), ifp
->int_name
);
435 /* Find the best discovered route,
436 * and discard stale routers.
441 struct dr
*drp
, *new_drp
;
444 struct interface
*ifp
;
449 /* Find the best discovered route.
452 for (drp
= drs
; drp
< &drs
[MAX_ADS
]; drp
++) {
457 /* Get rid of expired discovered routers.
459 if (drp
->dr_ts
+ drp
->dr_life
<= now
.tv_sec
) {
464 LIM_SEC(rdisc_timer
, drp
->dr_ts
+drp
->dr_life
+1);
466 /* Update preference with possibly changed interface
469 drp
->dr_pref
= PREF(drp
->dr_recv_pref
, ifp
);
471 /* Prefer the current route to prevent thrashing.
472 * Prefer shorter lifetimes to speed the detection of
474 * Avoid sick interfaces.
477 || (!((new_st
^ drp
->dr_ifp
->int_state
) & IS_SICK
)
478 && (new_pref
< drp
->dr_pref
479 || (new_pref
== drp
->dr_pref
481 || (new_drp
!= cur_drp
482 && new_drp
->dr_life
> drp
->dr_life
)))))
483 || ((new_st
& IS_SICK
)
484 && !(drp
->dr_ifp
->int_state
& IS_SICK
))) {
486 new_st
= drp
->dr_ifp
->int_state
;
487 new_pref
= drp
->dr_pref
;
491 /* switch to a better default route
493 if (new_drp
!= cur_drp
) {
494 rt
= rtget(RIP_DEFAULT
, 0);
496 /* Stop using discovered routes if they are all bad
498 if (new_drp
== NULL
) {
499 trace_act("turn off Router Discovery client");
503 && (rt
->rt_state
& RS_RDISC
)) {
504 new = rt
->rt_spares
[0];
505 new.rts_metric
= HOPCNT_INFINITY
;
506 new.rts_time
= now
.tv_sec
- GARBAGE_TIME
;
507 rtchange(rt
, rt
->rt_state
& ~RS_RDISC
,
513 if (cur_drp
== NULL
) {
514 trace_act("turn on Router Discovery client"
516 naddr_ntoa(new_drp
->dr_gate
),
517 new_drp
->dr_ifp
->int_name
);
521 trace_act("switch Router Discovery from"
522 " %s via %s to %s via %s",
523 naddr_ntoa(cur_drp
->dr_gate
),
524 cur_drp
->dr_ifp
->int_name
,
525 naddr_ntoa(new_drp
->dr_gate
),
526 new_drp
->dr_ifp
->int_name
);
529 memset(&new, 0, sizeof(new));
530 new.rts_ifp
= new_drp
->dr_ifp
;
531 new.rts_gate
= new_drp
->dr_gate
;
532 new.rts_router
= new_drp
->dr_gate
;
533 new.rts_metric
= HOPCNT_INFINITY
-1;
534 new.rts_time
= now
.tv_sec
;
536 rtchange(rt
, rt
->rt_state
| RS_RDISC
, &new, 0);
538 rtadd(RIP_DEFAULT
, 0, RS_RDISC
, &new);
545 /* turn RIP on or off */
546 if (!rdisc_ok
|| rip_interfaces
> 1) {
554 /* handle a single address in an advertisement
559 n_long pref
, /* signed and in network order */
560 u_short life
, /* in host byte order */
561 struct interface
*ifp
)
563 static struct msg_limit bad_gate
;
564 struct dr
*drp
, *new_drp
;
567 if (gate
== RIP_DEFAULT
568 || !check_dst(gate
)) {
569 msglim(&bad_gate
, from
,"router %s advertising bad gateway %s",
575 /* ignore pointers to ourself and routes via unreachable networks
577 if (ifwithaddr(gate
, 1, 0) != 0) {
578 trace_pkt(" discard Router Discovery Ad pointing at us");
581 if (!on_net(gate
, ifp
->int_net
, ifp
->int_mask
)) {
582 trace_pkt(" discard Router Discovery Ad"
583 " toward unreachable net");
587 /* Convert preference to an unsigned value
588 * and later bias it by the metric of the interface.
590 pref
= UNSIGN_PREF(ntohl(pref
));
592 if (pref
== 0 || life
< MinMaxAdvertiseInterval
) {
597 for (new_drp
= NULL
, drp
= drs
; drp
< &drs
[MAX_ADS
]; drp
++) {
598 /* accept new info for a familiar entry
600 if (drp
->dr_gate
== gate
) {
606 continue; /* do not worry about dead ads */
608 if (drp
->dr_ts
== 0) {
609 new_drp
= drp
; /* use unused entry */
611 } else if (new_drp
== NULL
) {
612 /* look for an entry worse than the new one to
615 if ((!(ifp
->int_state
& IS_SICK
)
616 && (drp
->dr_ifp
->int_state
& IS_SICK
))
617 || (pref
> drp
->dr_pref
618 && !((ifp
->int_state
^ drp
->dr_ifp
->int_state
)
622 } else if (new_drp
->dr_ts
!= 0) {
623 /* look for the least valuable entry to reuse
625 if ((!(new_drp
->dr_ifp
->int_state
& IS_SICK
)
626 && (drp
->dr_ifp
->int_state
& IS_SICK
))
627 || (new_drp
->dr_pref
> drp
->dr_pref
628 && !((new_drp
->dr_ifp
->int_state
629 ^ drp
->dr_ifp
->int_state
)
635 /* forget it if all of the current entries are better */
639 new_drp
->dr_ifp
= ifp
;
640 new_drp
->dr_gate
= gate
;
641 new_drp
->dr_ts
= now
.tv_sec
;
642 new_drp
->dr_life
= life
;
643 new_drp
->dr_recv_pref
= pref
;
644 /* bias functional preference by metric of the interface */
645 new_drp
->dr_pref
= PREF(pref
,ifp
);
647 /* after hearing a good advertisement, stop asking
649 if (!(ifp
->int_state
& IS_SICK
))
650 ifp
->int_rdisc_cnt
= MAX_SOLICITATIONS
;
654 /* Compute the IP checksum
655 * This assumes the packet is less than 32K long.
662 int nwords
= len
>> 1;
664 while (nwords
-- != 0)
670 /* end-around-carry */
671 sum
= (sum
>> 16) + (sum
& 0xffff);
677 /* Send a router discovery advertisement or solicitation ICMP packet.
680 send_rdisc(union ad_u
*p
,
682 struct interface
*ifp
,
683 naddr dst
, /* 0 or unicast destination */
684 int type
) /* 0=unicast, 1=bcast, 2=mcast */
686 struct sockaddr_in in
;
692 memset(&in
, 0, sizeof(in
));
693 in
.sin_addr
.s_addr
= dst
;
694 in
.sin_family
= AF_INET
;
696 in
.sin_len
= sizeof(in
);
698 flags
= MSG_DONTROUTE
;
701 case 0: /* unicast */
706 case 1: /* broadcast */
707 if (ifp
->int_if_flags
& IFF_POINTOPOINT
) {
708 msg
= "Send pt-to-pt";
709 in
.sin_addr
.s_addr
= ifp
->int_dstaddr
;
711 msg
= "Send broadcast";
712 in
.sin_addr
.s_addr
= ifp
->int_brdaddr
;
716 case 2: /* multicast */
717 msg
= "Send multicast";
718 if (ifp
->int_state
& IS_DUP
) {
719 trace_act("abort multicast output via %s"
720 " with duplicate address",
724 if (rdisc_sock_mcast
!= ifp
) {
725 /* select the right interface. */
727 /* Do not specify the primary interface explicitly
728 * if we have the multicast point-to-point kernel
729 * bug, since the kernel will do the wrong thing
730 * if the local address of a point-to-point link
731 * is the same as the address of an ordinary
734 if (ifp
->int_addr
== myaddr
) {
738 tgt_mcast
= ifp
->int_addr
;
739 if (0 > setsockopt(rdisc_sock
,
740 IPPROTO_IP
, IP_MULTICAST_IF
,
741 &tgt_mcast
, sizeof(tgt_mcast
))) {
742 LOGERR("setsockopt(rdisc_sock,"
744 rdisc_sock_mcast
= NULL
;
747 rdisc_sock_mcast
= ifp
;
756 trace_rdisc(msg
, ifp
->int_addr
, in
.sin_addr
.s_addr
, ifp
,
759 if (0 > sendto(rdisc_sock
, p
, p_size
, flags
,
760 (struct sockaddr
*)&in
, sizeof(in
))) {
761 if (ifp
== NULL
|| !(ifp
->int_state
& IS_BROKE
))
762 msglog("sendto(%s%s%s): %s",
763 ifp
!= NULL
? ifp
->int_name
: "",
764 ifp
!= NULL
? ", " : "",
765 inet_ntoa(in
.sin_addr
),
773 /* Send an advertisement
776 send_adv(struct interface
*ifp
,
777 naddr dst
, /* 0 or unicast destination */
778 int type
) /* 0=unicast, 1=bcast, 2=mcast */
784 memset(&u
, 0, sizeof(u
.ad
));
786 u
.ad
.icmp_type
= ICMP_ROUTERADVERT
;
787 u
.ad
.icmp_ad_num
= 1;
788 u
.ad
.icmp_ad_asize
= sizeof(u
.ad
.icmp_ad_info
[0])/4;
790 u
.ad
.icmp_ad_life
= stopint
? 0 : htons(ifp
->int_rdisc_int
*3);
792 /* Convert the configured preference to an unsigned value,
793 * bias it by the interface metric, and then send it as a
794 * signed, network byte order value.
796 pref
= UNSIGN_PREF(ifp
->int_rdisc_pref
);
797 u
.ad
.icmp_ad_info
[0].icmp_ad_pref
= htonl(SIGN_PREF(PREF(pref
, ifp
)));
799 u
.ad
.icmp_ad_info
[0].icmp_ad_addr
= ifp
->int_addr
;
801 u
.ad
.icmp_cksum
= in_cksum((u_short
*)&u
.ad
, sizeof(u
.ad
));
803 send_rdisc(&u
, sizeof(u
.ad
), ifp
, dst
, type
);
807 /* Advertise for Router Discovery
812 struct interface
*ifp
;
817 rdisc_timer
.tv_sec
= now
.tv_sec
+ NEVER
;
819 for (ifp
= ifnet
; ifp
; ifp
= ifp
->int_next
) {
820 if (0 != (ifp
->int_state
& (IS_NO_ADV_OUT
| IS_BROKE
)))
823 if (!timercmp(&ifp
->int_rdisc_timer
, &now
, >)
825 send_adv(ifp
, htonl(INADDR_ALLHOSTS_GROUP
),
826 (ifp
->int_state
&IS_BCAST_RDISC
) ? 1 : 2);
827 ifp
->int_rdisc_cnt
++;
829 intvl_random(&ifp
->int_rdisc_timer
,
830 (ifp
->int_rdisc_int
*3)/4,
832 if (ifp
->int_rdisc_cnt
< MAX_INITIAL_ADVERTS
833 && (ifp
->int_rdisc_timer
.tv_sec
834 > MAX_INITIAL_ADVERT_INTERVAL
)) {
835 ifp
->int_rdisc_timer
.tv_sec
836 = MAX_INITIAL_ADVERT_INTERVAL
;
838 timevaladd(&ifp
->int_rdisc_timer
, &now
);
841 if (timercmp(&rdisc_timer
, &ifp
->int_rdisc_timer
, >))
842 rdisc_timer
= ifp
->int_rdisc_timer
;
847 /* Solicit for Router Discovery
852 struct interface
*ifp
;
859 rdisc_timer
.tv_sec
= now
.tv_sec
+ NEVER
;
861 for (ifp
= ifnet
; ifp
; ifp
= ifp
->int_next
) {
862 if (0 != (ifp
->int_state
& (IS_NO_SOL_OUT
| IS_BROKE
))
863 || ifp
->int_rdisc_cnt
>= MAX_SOLICITATIONS
)
866 if (!timercmp(&ifp
->int_rdisc_timer
, &now
, >)) {
867 memset(&u
, 0, sizeof(u
.so
));
868 u
.so
.icmp_type
= ICMP_ROUTERSOLICIT
;
869 u
.so
.icmp_cksum
= in_cksum((u_short
*)&u
.so
,
871 send_rdisc(&u
, sizeof(u
.so
), ifp
,
872 htonl(INADDR_ALLROUTERS_GROUP
),
873 ((ifp
->int_state
&IS_BCAST_RDISC
) ? 1 : 2));
875 if (++ifp
->int_rdisc_cnt
>= MAX_SOLICITATIONS
)
878 ifp
->int_rdisc_timer
.tv_sec
= SOLICITATION_INTERVAL
;
879 ifp
->int_rdisc_timer
.tv_usec
= 0;
880 timevaladd(&ifp
->int_rdisc_timer
, &now
);
883 if (timercmp(&rdisc_timer
, &ifp
->int_rdisc_timer
, >))
884 rdisc_timer
= ifp
->int_rdisc_timer
;
889 /* check the IP header of a possible Router Discovery ICMP packet */
890 static struct interface
* /* 0 if bad */
891 ck_icmp(const char *act
,
893 struct interface
*ifp
,
901 if (p
->icmp
.icmp_type
== ICMP_ROUTERADVERT
) {
902 type
= "advertisement";
903 } else if (p
->icmp
.icmp_type
== ICMP_ROUTERSOLICIT
) {
904 type
= "solicitation";
909 if (p
->icmp
.icmp_code
!= 0) {
910 trace_pkt("unrecognized ICMP Router %s code=%d from %s to %s",
911 type
, p
->icmp
.icmp_code
,
912 naddr_ntoa(from
), naddr_ntoa(to
));
916 trace_rdisc(act
, from
, to
, ifp
, p
, len
);
919 trace_pkt("unknown interface for router-discovery %s"
921 type
, naddr_ntoa(from
), naddr_ntoa(to
));
927 /* read packets from the router discovery socket
932 static struct msg_limit bad_asize
, bad_len
;
933 #ifdef USE_PASSIFNAME
934 static struct msg_limit bad_name
;
936 struct sockaddr_in from
;
940 #ifdef USE_PASSIFNAME
941 char ifname
[IFNAMSIZ
];
951 struct interface
*ifp
;
955 fromlen
= sizeof(from
);
956 cc
= recvfrom(rdisc_sock
, &buf
, sizeof(buf
), 0,
957 (struct sockaddr
*)&from
,
960 if (cc
< 0 && errno
!= EWOULDBLOCK
)
961 LOGERR("recvfrom(rdisc_sock)");
964 if (fromlen
!= sizeof(struct sockaddr_in
))
965 logbad(1,"impossible recvfrom(rdisc_sock) fromlen=%d",
967 #ifdef USE_PASSIFNAME
968 if ((cc
-= sizeof(buf
.ifname
)) < 0)
969 logbad(0,"missing USE_PASSIFNAME; only %d bytes",
970 cc
+sizeof(buf
.ifname
));
973 hlen
= buf
.pkt
.ip
.ip_hl
<< 2;
974 if (cc
< hlen
+ ICMP_MINLEN
)
976 p
= (union ad_u
*)&buf
.pkt
.b
[hlen
];
979 #ifdef USE_PASSIFNAME
980 ifp
= ifwithname(buf
.ifname
, 0);
982 msglim(&bad_name
, from
.sin_addr
.s_addr
,
983 "impossible rdisc if_ name %.*s",
984 IFNAMSIZ
, buf
.ifname
);
986 /* If we could tell the interface on which a packet from
987 * address 0 arrived, we could deal with such solicitations.
989 ifp
= ((from
.sin_addr
.s_addr
== 0)
990 ? 0 : iflookup(from
.sin_addr
.s_addr
));
992 ifp
= ck_icmp("Recv", from
.sin_addr
.s_addr
, ifp
,
993 buf
.pkt
.ip
.ip_dst
.s_addr
, p
, cc
);
996 if (ifwithaddr(from
.sin_addr
.s_addr
, 0, 0)) {
998 "discard our own Router Discovery message");
1002 switch (p
->icmp
.icmp_type
) {
1003 case ICMP_ROUTERADVERT
:
1004 if (p
->ad
.icmp_ad_asize
*4
1005 < (int)sizeof(p
->ad
.icmp_ad_info
[0])) {
1006 msglim(&bad_asize
, from
.sin_addr
.s_addr
,
1007 "intolerable rdisc address size=%d",
1008 p
->ad
.icmp_ad_asize
);
1011 if (p
->ad
.icmp_ad_num
== 0) {
1012 trace_pkt(" empty?");
1015 if (cc
!= (int)(sizeof(p
->ad
)
1016 - sizeof(p
->ad
.icmp_ad_info
)
1017 + (p
->ad
.icmp_ad_num
1018 * sizeof(p
->ad
.icmp_ad_info
[0])))) {
1019 msglim(&bad_len
, from
.sin_addr
.s_addr
,
1020 "rdisc length %d does not match ad_num"
1021 " %d", cc
, p
->ad
.icmp_ad_num
);
1026 if (ifp
->int_state
& IS_NO_ADV_IN
)
1029 wp
= &p
->ad
.icmp_ad_info
[0].icmp_ad_addr
;
1030 for (n
= 0; n
< p
->ad
.icmp_ad_num
; n
++) {
1031 parse_ad(from
.sin_addr
.s_addr
,
1033 ntohs(p
->ad
.icmp_ad_life
),
1035 wp
+= p
->ad
.icmp_ad_asize
;
1040 case ICMP_ROUTERSOLICIT
:
1043 if (ifp
->int_state
& IS_NO_ADV_OUT
)
1049 * We should handle messages from address 0.
1052 /* Respond with a point-to-point advertisement */
1053 send_adv(ifp
, from
.sin_addr
.s_addr
, 0);