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[dragonfly.git] / sbin / routed / rdisc.c
blob0e15d4ae3698d583e1d813825e9a1ce9a7d555ba
1 /*
2 * Copyright (c) 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
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
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
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 1.4 2005/03/16 21:21:34 cpressey Exp $
35 */
36
37 #include "defs.h"
38 #include <netinet/in_systm.h>
39 #include <netinet/ip.h>
40 #include <netinet/ip_icmp.h>
41
42 #if !defined(sgi) && !defined(__NetBSD__)
43 static char sccsid[] __attribute__((unused)) = "@(#)rdisc.c 8.1 (Berkeley) x/y/95";
44 #elif defined(__NetBSD__)
45 __RCSID("$NetBSD$");
46 #endif
47
48 /* router advertisement ICMP packet */
49 struct icmp_ad {
50 u_int8_t icmp_type; /* type of message */
51 u_int8_t icmp_code; /* type sub code */
52 u_int16_t icmp_cksum; /* ones complement cksum of struct */
53 u_int8_t icmp_ad_num; /* # of following router addresses */
54 u_int8_t icmp_ad_asize; /* 2--words in each advertisement */
55 u_int16_t icmp_ad_life; /* seconds of validity */
56 struct icmp_ad_info {
57 n_long icmp_ad_addr;
58 n_long icmp_ad_pref;
59 } icmp_ad_info[1];
60 };
61
62 /* router solicitation ICMP packet */
63 struct icmp_so {
64 u_int8_t icmp_type; /* type of message */
65 u_int8_t icmp_code; /* type sub code */
66 u_int16_t icmp_cksum; /* ones complement cksum of struct */
67 n_long icmp_so_rsvd;
68 };
69
70 union ad_u {
71 struct icmp icmp;
72 struct icmp_ad ad;
73 struct icmp_so so;
74 };
75
76
77 int rdisc_sock = -1; /* router-discovery raw socket */
78 struct interface *rdisc_sock_mcast; /* current multicast interface */
79
80 struct timeval rdisc_timer;
81 int rdisc_ok; /* using solicited route */
82
83
84 #define MAX_ADS 16 /* at least one per interface */
85 struct dr { /* accumulated advertisements */
86 struct interface *dr_ifp;
87 naddr dr_gate; /* gateway */
88 time_t dr_ts; /* when received */
89 time_t dr_life; /* lifetime in host byte order */
90 n_long dr_recv_pref; /* received but biased preference */
91 n_long dr_pref; /* preference adjusted by metric */
92 } *cur_drp, drs[MAX_ADS];
93
94 /* convert between signed, balanced around zero,
95 * and unsigned zero-based preferences */
96 #define SIGN_PREF(p) ((p) ^ MIN_PreferenceLevel)
97 #define UNSIGN_PREF(p) SIGN_PREF(p)
98 /* adjust unsigned preference by interface metric,
99 * without driving it to infinity */
100 #define PREF(p, ifp) ((int)(p) <= (ifp)->int_metric ? ((p) != 0 ? 1 : 0) \
101 : (p) - ((ifp)->int_metric))
102
103 static void rdisc_sort(void);
104
105
106 /* dump an ICMP Router Discovery Advertisement Message
107 */
108 static void
109 trace_rdisc(const char *act,
110 naddr from,
111 naddr to,
112 struct interface *ifp,
113 union ad_u *p,
114 u_int len)
115 {
116 int i;
117 n_long *wp, *lim;
118
119
120 if (!TRACEPACKETS || ftrace == 0)
121 return;
122
123 lastlog();
124
125 if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
126 fprintf(ftrace, "%s Router Ad"
127 " from %s to %s via %s life=%d\n",
128 act, naddr_ntoa(from), naddr_ntoa(to),
129 ifp ? ifp->int_name : "?",
130 ntohs(p->ad.icmp_ad_life));
131 if (!TRACECONTENTS)
132 return;
133
134 wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
135 lim = &wp[(len - sizeof(p->ad)) / sizeof(*wp)];
136 for (i = 0; i < p->ad.icmp_ad_num && wp <= lim; i++) {
137 fprintf(ftrace, "\t%s preference=%d",
138 naddr_ntoa(wp[0]), (int)ntohl(wp[1]));
139 wp += p->ad.icmp_ad_asize;
140 }
141 fputc('\n',ftrace);
142
143 } else {
144 trace_act("%s Router Solic. from %s to %s via %s value=%#x",
145 act, naddr_ntoa(from), naddr_ntoa(to),
146 ifp ? ifp->int_name : "?",
147 (int)ntohl(p->so.icmp_so_rsvd));
148 }
149 }
150
151 /* prepare Router Discovery socket.
152 */
153 static void
154 get_rdisc_sock(void)
155 {
156 if (rdisc_sock < 0) {
157 rdisc_sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
158 if (rdisc_sock < 0)
159 BADERR(1,"rdisc_sock = socket()");
160 fix_sock(rdisc_sock,"rdisc_sock");
161 fix_select();
162 }
163 }
164
165
166 /* Pick multicast group for router-discovery socket
167 */
168 void
169 set_rdisc_mg(struct interface *ifp,
170 int on) /* 0=turn it off */
171 {
172 struct ip_mreq m;
173
174 if (rdisc_sock < 0) {
175 /* Create the raw socket so that we can hear at least
176 * broadcast router discovery packets.
177 */
178 if ((ifp->int_state & IS_NO_RDISC) == IS_NO_RDISC
179 || !on)
180 return;
181 get_rdisc_sock();
182 }
183
184 if (!(ifp->int_if_flags & IFF_MULTICAST)) {
185 ifp->int_state &= ~(IS_ALL_HOSTS | IS_ALL_ROUTERS);
186 return;
187 }
188
189 #ifdef MCAST_PPP_BUG
190 if (ifp->int_if_flags & IFF_POINTOPOINT)
191 return;
192 #endif
193 memset(&m, 0, sizeof(m));
194 m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)
195 ? ifp->int_dstaddr
196 : ifp->int_addr);
197 if (supplier
198 || (ifp->int_state & IS_NO_ADV_IN)
199 || !on) {
200 /* stop listening to advertisements
201 */
202 if (ifp->int_state & IS_ALL_HOSTS) {
203 m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
204 if (setsockopt(rdisc_sock, IPPROTO_IP,
205 IP_DROP_MEMBERSHIP,
206 &m, sizeof(m)) < 0)
207 LOGERR("IP_DROP_MEMBERSHIP ALLHOSTS");
208 ifp->int_state &= ~IS_ALL_HOSTS;
209 }
210
211 } else if (!(ifp->int_state & IS_ALL_HOSTS)) {
212 /* start listening to advertisements
213 */
214 m.imr_multiaddr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
215 if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
216 &m, sizeof(m)) < 0) {
217 LOGERR("IP_ADD_MEMBERSHIP ALLHOSTS");
218 } else {
219 ifp->int_state |= IS_ALL_HOSTS;
220 }
221 }
222
223 if (!supplier
224 || (ifp->int_state & IS_NO_ADV_OUT)
225 || !on) {
226 /* stop listening to solicitations
227 */
228 if (ifp->int_state & IS_ALL_ROUTERS) {
229 m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
230 if (setsockopt(rdisc_sock, IPPROTO_IP,
231 IP_DROP_MEMBERSHIP,
232 &m, sizeof(m)) < 0)
233 LOGERR("IP_DROP_MEMBERSHIP ALLROUTERS");
234 ifp->int_state &= ~IS_ALL_ROUTERS;
235 }
236
237 } else if (!(ifp->int_state & IS_ALL_ROUTERS)) {
238 /* start hearing solicitations
239 */
240 m.imr_multiaddr.s_addr=htonl(INADDR_ALLROUTERS_GROUP);
241 if (setsockopt(rdisc_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
242 &m, sizeof(m)) < 0) {
243 LOGERR("IP_ADD_MEMBERSHIP ALLROUTERS");
244 } else {
245 ifp->int_state |= IS_ALL_ROUTERS;
246 }
247 }
248 }
249
250
251 /* start supplying routes
252 */
253 void
254 set_supplier(void)
255 {
256 struct interface *ifp;
257 struct dr *drp;
258
259 if (supplier_set)
260 return;
261
262 trace_act("start supplying routes");
263
264 /* Forget discovered routes.
265 */
266 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
267 drp->dr_recv_pref = 0;
268 drp->dr_life = 0;
269 }
270 rdisc_age(0);
271
272 supplier_set = 1;
273 supplier = 1;
274
275 /* Do not start advertising until we have heard some RIP routes */
276 LIM_SEC(rdisc_timer, now.tv_sec+MIN_WAITTIME);
277
278 /* Switch router discovery multicast groups from soliciting
279 * to advertising.
280 */
281 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
282 if (ifp->int_state & IS_BROKE)
283 continue;
284 ifp->int_rdisc_cnt = 0;
285 ifp->int_rdisc_timer.tv_usec = rdisc_timer.tv_usec;
286 ifp->int_rdisc_timer.tv_sec = now.tv_sec+MIN_WAITTIME;
287 set_rdisc_mg(ifp, 1);
288 }
289
290 /* get rid of any redirects */
291 del_redirects(0,0);
292 }
293
294
295 /* age discovered routes and find the best one
296 */
297 void
298 rdisc_age(naddr bad_gate)
299 {
300 time_t sec;
301 struct dr *drp;
302
303
304 /* If only advertising, then do only that. */
305 if (supplier) {
306 /* If switching from client to server, get rid of old
307 * default routes.
308 */
309 if (cur_drp != 0)
310 rdisc_sort();
311 rdisc_adv();
312 return;
313 }
314
315 /* If we are being told about a bad router,
316 * then age the discovered default route, and if there is
317 * no alternative, solicit a replacement.
318 */
319 if (bad_gate != 0) {
320 /* Look for the bad discovered default route.
321 * Age it and note its interface.
322 */
323 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
324 if (drp->dr_ts == 0)
325 continue;
326
327 /* When we find the bad router, then age the route
328 * to at most SUPPLY_INTERVAL.
329 * This is contrary to RFC 1256, but defends against
330 * black holes.
331 */
332 if (drp->dr_gate == bad_gate) {
333 sec = (now.tv_sec - drp->dr_life
334 + SUPPLY_INTERVAL);
335 if (drp->dr_ts > sec) {
336 trace_act("age 0.0.0.0 --> %s via %s",
337 naddr_ntoa(drp->dr_gate),
338 drp->dr_ifp->int_name);
339 drp->dr_ts = sec;
340 }
341 break;
342 }
343 }
344 }
345
346 rdisc_sol();
347 rdisc_sort();
348
349 /* Delete old redirected routes to keep the kernel table small,
350 * and to prevent black holes. Check that the kernel table
351 * matches the daemon table (i.e. has the default route).
352 * But only if RIP is not running and we are not dealing with
353 * a bad gateway, since otherwise age() will be called.
354 */
355 if (rip_sock < 0 && bad_gate == 0)
356 age(0);
357 }
358
359
360 /* Zap all routes discovered via an interface that has gone bad
361 * This should only be called when !(ifp->int_state & IS_ALIAS)
362 */
363 void
364 if_bad_rdisc(struct interface *ifp)
365 {
366 struct dr *drp;
367
368 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
369 if (drp->dr_ifp != ifp)
370 continue;
371 drp->dr_recv_pref = 0;
372 drp->dr_ts = 0;
373 drp->dr_life = 0;
374 }
375
376 /* make a note to re-solicit, turn RIP on or off, etc. */
377 rdisc_timer.tv_sec = 0;
378 }
379
380
381 /* mark an interface ok for router discovering.
382 */
383 void
384 if_ok_rdisc(struct interface *ifp)
385 {
386 set_rdisc_mg(ifp, 1);
387
388 ifp->int_rdisc_cnt = 0;
389 ifp->int_rdisc_timer.tv_sec = now.tv_sec + (supplier
390 ? MIN_WAITTIME
391 : MAX_SOLICITATION_DELAY);
392 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
393 rdisc_timer = ifp->int_rdisc_timer;
394 }
395
396
397 /* get rid of a dead discovered router
398 */
399 static void
400 del_rdisc(struct dr *drp)
401 {
402 struct interface *ifp;
403 naddr gate;
404 int i;
405
406
407 del_redirects(gate = drp->dr_gate, 0);
408 drp->dr_ts = 0;
409 drp->dr_life = 0;
410
411
412 /* Count the other discovered routes on the interface.
413 */
414 i = 0;
415 ifp = drp->dr_ifp;
416 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
417 if (drp->dr_ts != 0
418 && drp->dr_ifp == ifp)
419 i++;
420 }
421
422 /* If that was the last good discovered router on the interface,
423 * then solicit a new one.
424 * This is contrary to RFC 1256, but defends against black holes.
425 */
426 if (i != 0) {
427 trace_act("discovered router %s via %s"
428 " is bad--have %d remaining",
429 naddr_ntoa(gate), ifp->int_name, i);
430 } else if (ifp->int_rdisc_cnt >= MAX_SOLICITATIONS) {
431 trace_act("last discovered router %s via %s"
432 " is bad--re-solicit",
433 naddr_ntoa(gate), ifp->int_name);
434 ifp->int_rdisc_cnt = 0;
435 ifp->int_rdisc_timer.tv_sec = 0;
436 rdisc_sol();
437 } else {
438 trace_act("last discovered router %s via %s"
439 " is bad--wait to solicit",
440 naddr_ntoa(gate), ifp->int_name);
441 }
442 }
443
444
445 /* Find the best discovered route,
446 * and discard stale routers.
447 */
448 static void
449 rdisc_sort(void)
450 {
451 struct dr *drp, *new_drp;
452 struct rt_entry *rt;
453 struct rt_spare new;
454 struct interface *ifp;
455 u_int new_st = 0;
456 n_long new_pref = 0;
457
458
459 /* Find the best discovered route.
460 */
461 new_drp = 0;
462 for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
463 if (drp->dr_ts == 0)
464 continue;
465 ifp = drp->dr_ifp;
466
467 /* Get rid of expired discovered routers.
468 */
469 if (drp->dr_ts + drp->dr_life <= now.tv_sec) {
470 del_rdisc(drp);
471 continue;
472 }
473
474 LIM_SEC(rdisc_timer, drp->dr_ts+drp->dr_life+1);
475
476 /* Update preference with possibly changed interface
477 * metric.
478 */
479 drp->dr_pref = PREF(drp->dr_recv_pref, ifp);
480
481 /* Prefer the current route to prevent thrashing.
482 * Prefer shorter lifetimes to speed the detection of
483 * bad routers.
484 * Avoid sick interfaces.
485 */
486 if (new_drp == 0
487 || (!((new_st ^ drp->dr_ifp->int_state) & IS_SICK)
488 && (new_pref < drp->dr_pref
489 || (new_pref == drp->dr_pref
490 && (drp == cur_drp
491 || (new_drp != cur_drp
492 && new_drp->dr_life > drp->dr_life)))))
493 || ((new_st & IS_SICK)
494 && !(drp->dr_ifp->int_state & IS_SICK))) {
495 new_drp = drp;
496 new_st = drp->dr_ifp->int_state;
497 new_pref = drp->dr_pref;
498 }
499 }
500
501 /* switch to a better default route
502 */
503 if (new_drp != cur_drp) {
504 rt = rtget(RIP_DEFAULT, 0);
505
506 /* Stop using discovered routes if they are all bad
507 */
508 if (new_drp == 0) {
509 trace_act("turn off Router Discovery client");
510 rdisc_ok = 0;
511
512 if (rt != 0
513 && (rt->rt_state & RS_RDISC)) {
514 new = rt->rt_spares[0];
515 new.rts_metric = HOPCNT_INFINITY;
516 new.rts_time = now.tv_sec - GARBAGE_TIME;
517 rtchange(rt, rt->rt_state & ~RS_RDISC,
518 &new, 0);
519 rtswitch(rt, 0);
520 }
521
522 } else {
523 if (cur_drp == 0) {
524 trace_act("turn on Router Discovery client"
525 " using %s via %s",
526 naddr_ntoa(new_drp->dr_gate),
527 new_drp->dr_ifp->int_name);
528 rdisc_ok = 1;
529
530 } else {
531 trace_act("switch Router Discovery from"
532 " %s via %s to %s via %s",
533 naddr_ntoa(cur_drp->dr_gate),
534 cur_drp->dr_ifp->int_name,
535 naddr_ntoa(new_drp->dr_gate),
536 new_drp->dr_ifp->int_name);
537 }
538
539 memset(&new, 0, sizeof(new));
540 new.rts_ifp = new_drp->dr_ifp;
541 new.rts_gate = new_drp->dr_gate;
542 new.rts_router = new_drp->dr_gate;
543 new.rts_metric = HOPCNT_INFINITY-1;
544 new.rts_time = now.tv_sec;
545 if (rt != 0) {
546 rtchange(rt, rt->rt_state | RS_RDISC, &new, 0);
547 } else {
548 rtadd(RIP_DEFAULT, 0, RS_RDISC, &new);
549 }
550 }
551
552 cur_drp = new_drp;
553 }
554
555 /* turn RIP on or off */
556 if (!rdisc_ok || rip_interfaces > 1) {
557 rip_on(0);
558 } else {
559 rip_off();
560 }
561 }
562
563
564 /* handle a single address in an advertisement
565 */
566 static void
567 parse_ad(naddr from,
568 naddr gate,
569 n_long pref, /* signed and in network order */
570 u_short life, /* in host byte order */
571 struct interface *ifp)
572 {
573 static struct msg_limit bad_gate;
574 struct dr *drp, *new_drp;
575
576
577 if (gate == RIP_DEFAULT
578 || !check_dst(gate)) {
579 msglim(&bad_gate, from,"router %s advertising bad gateway %s",
580 naddr_ntoa(from),
581 naddr_ntoa(gate));
582 return;
583 }
584
585 /* ignore pointers to ourself and routes via unreachable networks
586 */
587 if (ifwithaddr(gate, 1, 0) != 0) {
588 trace_pkt(" discard Router Discovery Ad pointing at us");
589 return;
590 }
591 if (!on_net(gate, ifp->int_net, ifp->int_mask)) {
592 trace_pkt(" discard Router Discovery Ad"
593 " toward unreachable net");
594 return;
595 }
596
597 /* Convert preference to an unsigned value
598 * and later bias it by the metric of the interface.
599 */
600 pref = UNSIGN_PREF(ntohl(pref));
601
602 if (pref == 0 || life < MinMaxAdvertiseInterval) {
603 pref = 0;
604 life = 0;
605 }
606
607 for (new_drp = 0, drp = drs; drp < &drs[MAX_ADS]; drp++) {
608 /* accept new info for a familiar entry
609 */
610 if (drp->dr_gate == gate) {
611 new_drp = drp;
612 break;
613 }
614
615 if (life == 0)
616 continue; /* do not worry about dead ads */
617
618 if (drp->dr_ts == 0) {
619 new_drp = drp; /* use unused entry */
620
621 } else if (new_drp == 0) {
622 /* look for an entry worse than the new one to
623 * reuse.
624 */
625 if ((!(ifp->int_state & IS_SICK)
626 && (drp->dr_ifp->int_state & IS_SICK))
627 || (pref > drp->dr_pref
628 && !((ifp->int_state ^ drp->dr_ifp->int_state)
629 & IS_SICK)))
630 new_drp = drp;
631
632 } else if (new_drp->dr_ts != 0) {
633 /* look for the least valuable entry to reuse
634 */
635 if ((!(new_drp->dr_ifp->int_state & IS_SICK)
636 && (drp->dr_ifp->int_state & IS_SICK))
637 || (new_drp->dr_pref > drp->dr_pref
638 && !((new_drp->dr_ifp->int_state
639 ^ drp->dr_ifp->int_state)
640 & IS_SICK)))
641 new_drp = drp;
642 }
643 }
644
645 /* forget it if all of the current entries are better */
646 if (new_drp == 0)
647 return;
648
649 new_drp->dr_ifp = ifp;
650 new_drp->dr_gate = gate;
651 new_drp->dr_ts = now.tv_sec;
652 new_drp->dr_life = life;
653 new_drp->dr_recv_pref = pref;
654 /* bias functional preference by metric of the interface */
655 new_drp->dr_pref = PREF(pref,ifp);
656
657 /* after hearing a good advertisement, stop asking
658 */
659 if (!(ifp->int_state & IS_SICK))
660 ifp->int_rdisc_cnt = MAX_SOLICITATIONS;
661 }
662
663
664 /* Compute the IP checksum
665 * This assumes the packet is less than 32K long.
666 */
667 static u_short
668 in_cksum(u_short *p,
669 u_int len)
670 {
671 u_int sum = 0;
672 int nwords = len >> 1;
673
674 while (nwords-- != 0)
675 sum += *p++;
676
677 if (len & 1)
678 sum += *(u_char *)p;
679
680 /* end-around-carry */
681 sum = (sum >> 16) + (sum & 0xffff);
682 sum += (sum >> 16);
683 return (~sum);
684 }
685
686
687 /* Send a router discovery advertisement or solicitation ICMP packet.
688 */
689 static void
690 send_rdisc(union ad_u *p,
691 int p_size,
692 struct interface *ifp,
693 naddr dst, /* 0 or unicast destination */
694 int type) /* 0=unicast, 1=bcast, 2=mcast */
695 {
696 struct sockaddr_in in;
697 int flags;
698 const char *msg;
699 naddr tgt_mcast;
700
701
702 memset(&in, 0, sizeof(in));
703 in.sin_addr.s_addr = dst;
704 in.sin_family = AF_INET;
705 #ifdef _HAVE_SIN_LEN
706 in.sin_len = sizeof(in);
707 #endif
708 flags = MSG_DONTROUTE;
709
710 switch (type) {
711 case 0: /* unicast */
712 default:
713 msg = "Send";
714 break;
715
716 case 1: /* broadcast */
717 if (ifp->int_if_flags & IFF_POINTOPOINT) {
718 msg = "Send pt-to-pt";
719 in.sin_addr.s_addr = ifp->int_dstaddr;
720 } else {
721 msg = "Send broadcast";
722 in.sin_addr.s_addr = ifp->int_brdaddr;
723 }
724 break;
725
726 case 2: /* multicast */
727 msg = "Send multicast";
728 if (ifp->int_state & IS_DUP) {
729 trace_act("abort multicast output via %s"
730 " with duplicate address",
731 ifp->int_name);
732 return;
733 }
734 if (rdisc_sock_mcast != ifp) {
735 /* select the right interface. */
736 #ifdef MCAST_PPP_BUG
737 /* Do not specify the primary interface explicitly
738 * if we have the multicast point-to-point kernel
739 * bug, since the kernel will do the wrong thing
740 * if the local address of a point-to-point link
741 * is the same as the address of an ordinary
742 * interface.
743 */
744 if (ifp->int_addr == myaddr) {
745 tgt_mcast = 0;
746 } else
747 #endif
748 tgt_mcast = ifp->int_addr;
749 if (0 > setsockopt(rdisc_sock,
750 IPPROTO_IP, IP_MULTICAST_IF,
751 &tgt_mcast, sizeof(tgt_mcast))) {
752 LOGERR("setsockopt(rdisc_sock,"
753 "IP_MULTICAST_IF)");
754 rdisc_sock_mcast = 0;
755 return;
756 }
757 rdisc_sock_mcast = ifp;
758 }
759 flags = 0;
760 break;
761 }
762
763 if (rdisc_sock < 0)
764 get_rdisc_sock();
765
766 trace_rdisc(msg, ifp->int_addr, in.sin_addr.s_addr, ifp,
767 p, p_size);
768
769 if (0 > sendto(rdisc_sock, p, p_size, flags,
770 (struct sockaddr *)&in, sizeof(in))) {
771 if (ifp == 0 || !(ifp->int_state & IS_BROKE))
772 msglog("sendto(%s%s%s): %s",
773 ifp != 0 ? ifp->int_name : "",
774 ifp != 0 ? ", " : "",
775 inet_ntoa(in.sin_addr),
776 strerror(errno));
777 if (ifp != 0)
778 if_sick(ifp);
779 }
780 }
781
782
783 /* Send an advertisement
784 */
785 static void
786 send_adv(struct interface *ifp,
787 naddr dst, /* 0 or unicast destination */
788 int type) /* 0=unicast, 1=bcast, 2=mcast */
789 {
790 union ad_u u;
791 n_long pref;
792
793
794 memset(&u, 0, sizeof(u.ad));
795
796 u.ad.icmp_type = ICMP_ROUTERADVERT;
797 u.ad.icmp_ad_num = 1;
798 u.ad.icmp_ad_asize = sizeof(u.ad.icmp_ad_info[0])/4;
799
800 u.ad.icmp_ad_life = stopint ? 0 : htons(ifp->int_rdisc_int*3);
801
802 /* Convert the configured preference to an unsigned value,
803 * bias it by the interface metric, and then send it as a
804 * signed, network byte order value.
805 */
806 pref = UNSIGN_PREF(ifp->int_rdisc_pref);
807 u.ad.icmp_ad_info[0].icmp_ad_pref = htonl(SIGN_PREF(PREF(pref, ifp)));
808
809 u.ad.icmp_ad_info[0].icmp_ad_addr = ifp->int_addr;
810
811 u.ad.icmp_cksum = in_cksum((u_short*)&u.ad, sizeof(u.ad));
812
813 send_rdisc(&u, sizeof(u.ad), ifp, dst, type);
814 }
815
816
817 /* Advertise for Router Discovery
818 */
819 void
820 rdisc_adv(void)
821 {
822 struct interface *ifp;
823
824 if (!supplier)
825 return;
826
827 rdisc_timer.tv_sec = now.tv_sec + NEVER;
828
829 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
830 if (0 != (ifp->int_state & (IS_NO_ADV_OUT | IS_BROKE)))
831 continue;
832
833 if (!timercmp(&ifp->int_rdisc_timer, &now, >)
834 || stopint) {
835 send_adv(ifp, htonl(INADDR_ALLHOSTS_GROUP),
836 (ifp->int_state&IS_BCAST_RDISC) ? 1 : 2);
837 ifp->int_rdisc_cnt++;
838
839 intvl_random(&ifp->int_rdisc_timer,
840 (ifp->int_rdisc_int*3)/4,
841 ifp->int_rdisc_int);
842 if (ifp->int_rdisc_cnt < MAX_INITIAL_ADVERTS
843 && (ifp->int_rdisc_timer.tv_sec
844 > MAX_INITIAL_ADVERT_INTERVAL)) {
845 ifp->int_rdisc_timer.tv_sec
846 = MAX_INITIAL_ADVERT_INTERVAL;
847 }
848 timevaladd(&ifp->int_rdisc_timer, &now);
849 }
850
851 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
852 rdisc_timer = ifp->int_rdisc_timer;
853 }
854 }
855
856
857 /* Solicit for Router Discovery
858 */
859 void
860 rdisc_sol(void)
861 {
862 struct interface *ifp;
863 union ad_u u;
864
865
866 if (supplier)
867 return;
868
869 rdisc_timer.tv_sec = now.tv_sec + NEVER;
870
871 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
872 if (0 != (ifp->int_state & (IS_NO_SOL_OUT | IS_BROKE))
873 || ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
874 continue;
875
876 if (!timercmp(&ifp->int_rdisc_timer, &now, >)) {
877 memset(&u, 0, sizeof(u.so));
878 u.so.icmp_type = ICMP_ROUTERSOLICIT;
879 u.so.icmp_cksum = in_cksum((u_short*)&u.so,
880 sizeof(u.so));
881 send_rdisc(&u, sizeof(u.so), ifp,
882 htonl(INADDR_ALLROUTERS_GROUP),
883 ((ifp->int_state&IS_BCAST_RDISC) ? 1 : 2));
884
885 if (++ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
886 continue;
887
888 ifp->int_rdisc_timer.tv_sec = SOLICITATION_INTERVAL;
889 ifp->int_rdisc_timer.tv_usec = 0;
890 timevaladd(&ifp->int_rdisc_timer, &now);
891 }
892
893 if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
894 rdisc_timer = ifp->int_rdisc_timer;
895 }
896 }
897
898
899 /* check the IP header of a possible Router Discovery ICMP packet */
900 static struct interface * /* 0 if bad */
901 ck_icmp(const char *act,
902 naddr from,
903 struct interface *ifp,
904 naddr to,
905 union ad_u *p,
906 u_int len)
907 {
908 const char *type;
909
910
911 if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
912 type = "advertisement";
913 } else if (p->icmp.icmp_type == ICMP_ROUTERSOLICIT) {
914 type = "solicitation";
915 } else {
916 return 0;
917 }
918
919 if (p->icmp.icmp_code != 0) {
920 trace_pkt("unrecognized ICMP Router %s code=%d from %s to %s",
921 type, p->icmp.icmp_code,
922 naddr_ntoa(from), naddr_ntoa(to));
923 return 0;
924 }
925
926 trace_rdisc(act, from, to, ifp, p, len);
927
928 if (ifp == 0)
929 trace_pkt("unknown interface for router-discovery %s"
930 " from %s to %s",
931 type, naddr_ntoa(from), naddr_ntoa(to));
932
933 return ifp;
934 }
935
936
937 /* read packets from the router discovery socket
938 */
939 void
940 read_d(void)
941 {
942 static struct msg_limit bad_asize, bad_len;
943 #ifdef USE_PASSIFNAME
944 static struct msg_limit bad_name;
945 #endif
946 struct sockaddr_in from;
947 int n, fromlen, cc, hlen;
948 struct {
949 #ifdef USE_PASSIFNAME
950 char ifname[IFNAMSIZ];
951 #endif
952 union {
953 struct ip ip;
954 u_short s[512/2];
955 u_char b[512];
956 } pkt;
957 } buf;
958 union ad_u *p;
959 n_long *wp;
960 struct interface *ifp;
961
962
963 for (;;) {
964 fromlen = sizeof(from);
965 cc = recvfrom(rdisc_sock, &buf, sizeof(buf), 0,
966 (struct sockaddr*)&from,
967 &fromlen);
968 if (cc <= 0) {
969 if (cc < 0 && errno != EWOULDBLOCK)
970 LOGERR("recvfrom(rdisc_sock)");
971 break;
972 }
973 if (fromlen != sizeof(struct sockaddr_in))
974 logbad(1,"impossible recvfrom(rdisc_sock) fromlen=%d",
975 fromlen);
976 #ifdef USE_PASSIFNAME
977 if ((cc -= sizeof(buf.ifname)) < 0)
978 logbad(0,"missing USE_PASSIFNAME; only %d bytes",
979 cc+sizeof(buf.ifname));
980 #endif
981
982 hlen = buf.pkt.ip.ip_hl << 2;
983 if (cc < hlen + ICMP_MINLEN)
984 continue;
985 p = (union ad_u *)&buf.pkt.b[hlen];
986 cc -= hlen;
987
988 #ifdef USE_PASSIFNAME
989 ifp = ifwithname(buf.ifname, 0);
990 if (ifp == 0)
991 msglim(&bad_name, from.sin_addr.s_addr,
992 "impossible rdisc if_ name %.*s",
993 IFNAMSIZ, buf.ifname);
994 #else
995 /* If we could tell the interface on which a packet from
996 * address 0 arrived, we could deal with such solicitations.
997 */
998 ifp = ((from.sin_addr.s_addr == 0)
999 ? 0 : iflookup(from.sin_addr.s_addr));
1000 #endif
1001 ifp = ck_icmp("Recv", from.sin_addr.s_addr, ifp,
1002 buf.pkt.ip.ip_dst.s_addr, p, cc);
1003 if (ifp == 0)
1004 continue;
1005 if (ifwithaddr(from.sin_addr.s_addr, 0, 0)) {
1006 trace_pkt(" "
1007 "discard our own Router Discovery message");
1008 continue;
1009 }
1010
1011 switch (p->icmp.icmp_type) {
1012 case ICMP_ROUTERADVERT:
1013 if (p->ad.icmp_ad_asize*4
1014 < (int)sizeof(p->ad.icmp_ad_info[0])) {
1015 msglim(&bad_asize, from.sin_addr.s_addr,
1016 "intolerable rdisc address size=%d",
1017 p->ad.icmp_ad_asize);
1018 continue;
1019 }
1020 if (p->ad.icmp_ad_num == 0) {
1021 trace_pkt(" empty?");
1022 continue;
1023 }
1024 if (cc != (int)(sizeof(p->ad)
1025 - sizeof(p->ad.icmp_ad_info)
1026 + (p->ad.icmp_ad_num
1027 * sizeof(p->ad.icmp_ad_info[0])))) {
1028 msglim(&bad_len, from.sin_addr.s_addr,
1029 "rdisc length %d does not match ad_num"
1030 " %d", cc, p->ad.icmp_ad_num);
1031 continue;
1032 }
1033 if (supplier)
1034 continue;
1035 if (ifp->int_state & IS_NO_ADV_IN)
1036 continue;
1037
1038 wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
1039 for (n = 0; n < p->ad.icmp_ad_num; n++) {
1040 parse_ad(from.sin_addr.s_addr,
1041 wp[0], wp[1],
1042 ntohs(p->ad.icmp_ad_life),
1043 ifp);
1044 wp += p->ad.icmp_ad_asize;
1045 }
1046 break;
1047
1048
1049 case ICMP_ROUTERSOLICIT:
1050 if (!supplier)
1051 continue;
1052 if (ifp->int_state & IS_NO_ADV_OUT)
1053 continue;
1054 if (stopint)
1055 continue;
1056
1057 /* XXX
1058 * We should handle messages from address 0.
1059 */
1060
1061 /* Respond with a point-to-point advertisement */
1062 send_adv(ifp, from.sin_addr.s_addr, 0);
1063 break;
1064 }
1065 }
1066
1067 rdisc_sort();
1068 }
DragonFly BSD