summaryrefslogtreecommitdiffstats
path: root/sbin/routed/output.c
blob: e0befc8056c8379f1f83f017384e0c2a39119888 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
/*
 * Copyright (c) 1983, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#include "defs.h"

#ifdef __NetBSD__
__RCSID("$NetBSD$");
#elif defined(__FreeBSD__)
__RCSID("$FreeBSD$");
#else
__RCSID("$Revision: 2.27 $");
#ident "$Revision: 2.27 $"
#endif
#ident "$FreeBSD$"


u_int update_seqno;


/* walk the tree of routes with this for output
 */
struct {
	struct sockaddr_in to;
	naddr	to_mask;
	naddr	to_net;
	naddr	to_std_mask;
	naddr	to_std_net;
	struct interface *ifp;		/* usually output interface */
	struct auth *a;
	char	metric;			/* adjust metrics by interface */
	int	npackets;
	int	gen_limit;
	u_int	state;
#define	    WS_ST_FLASH	    0x001	/* send only changed routes */
#define	    WS_ST_RIP2_ALL  0x002	/* send full featured RIPv2 */
#define	    WS_ST_AG	    0x004	/* ok to aggregate subnets */
#define	    WS_ST_SUPER_AG  0x008	/* ok to aggregate networks */
#define	    WS_ST_QUERY	    0x010	/* responding to a query */
#define	    WS_ST_TO_ON_NET 0x020	/* sending onto one of our nets */
#define	    WS_ST_DEFAULT   0x040	/* faking a default */
} ws;

/* A buffer for what can be heard by both RIPv1 and RIPv2 listeners */
struct ws_buf v12buf;
union pkt_buf ripv12_buf;

/* Another for only RIPv2 listeners */
struct ws_buf v2buf;
union pkt_buf rip_v2_buf;



void
bufinit(void)
{
	ripv12_buf.rip.rip_cmd = RIPCMD_RESPONSE;
	v12buf.buf = &ripv12_buf.rip;
	v12buf.base = &v12buf.buf->rip_nets[0];

	rip_v2_buf.rip.rip_cmd = RIPCMD_RESPONSE;
	rip_v2_buf.rip.rip_vers = RIPv2;
	v2buf.buf = &rip_v2_buf.rip;
	v2buf.base = &v2buf.buf->rip_nets[0];
}


/* Send the contents of the global buffer via the non-multicast socket
 */
int					/* <0 on failure */
output(enum output_type type,
       struct sockaddr_in *dst,		/* send to here */
       struct interface *ifp,
       struct rip *buf,
       int size)			/* this many bytes */
{
	struct sockaddr_in osin;
	int flags;
	const char *msg;
	int res;
	naddr tgt_mcast;
	int soc;
	int serrno;

	osin = *dst;
	if (osin.sin_port == 0)
		osin.sin_port = htons(RIP_PORT);
#ifdef _HAVE_SIN_LEN
	if (osin.sin_len == 0)
		osin.sin_len = sizeof(osin);
#endif

	soc = rip_sock;
	flags = 0;

	switch (type) {
	case OUT_QUERY:
		msg = "Answer Query";
		if (soc < 0)
			soc = ifp->int_rip_sock;
		break;
	case OUT_UNICAST:
		msg = "Send";
		if (soc < 0)
			soc = ifp->int_rip_sock;
		flags = MSG_DONTROUTE;
		break;
	case OUT_BROADCAST:
		if (ifp->int_if_flags & IFF_POINTOPOINT) {
			msg = "Send";
		} else {
			msg = "Send bcast";
		}
		flags = MSG_DONTROUTE;
		break;
	case OUT_MULTICAST:
		if (ifp->int_if_flags & IFF_POINTOPOINT) {
			msg = "Send pt-to-pt";
		} else if (ifp->int_state & IS_DUP) {
			trace_act("abort multicast output via %s"
				  " with duplicate address",
				  ifp->int_name);
			return 0;
		} else {
			msg = "Send mcast";
			if (rip_sock_mcast != ifp) {
#ifdef MCAST_IFINDEX
				/* specify ifindex */
				tgt_mcast = htonl(ifp->int_index);
#else
#ifdef MCAST_PPP_BUG
				/* Do not specify the primary interface
				 * explicitly if we have the multicast
				 * point-to-point kernel bug, since the
				 * kernel will do the wrong thing if the
				 * local address of a point-to-point link
				 * is the same as the address of an ordinary
				 * interface.
				 */
				if (ifp->int_addr == myaddr) {
					tgt_mcast = 0;
				} else
#endif
				tgt_mcast = ifp->int_addr;
#endif
				if (0 > setsockopt(rip_sock,
						   IPPROTO_IP, IP_MULTICAST_IF,
						   &tgt_mcast,
						   sizeof(tgt_mcast))) {
					serrno = errno;
					LOGERR("setsockopt(rip_sock,"
					       "IP_MULTICAST_IF)");
					errno = serrno;
					ifp = 0;
					return -1;
				}
				rip_sock_mcast = ifp;
			}
			osin.sin_addr.s_addr = htonl(INADDR_RIP_GROUP);
		}
		break;

	case NO_OUT_MULTICAST:
	case NO_OUT_RIPV2:
	default:
#ifdef DEBUG
		abort();
#endif
		return -1;
	}

	trace_rip(msg, "to", &osin, ifp, buf, size);

	res = sendto(soc, buf, size, flags,
		     (struct sockaddr *)&osin, sizeof(osin));
	if (res < 0
	    && (ifp == 0 || !(ifp->int_state & IS_BROKE))) {
		serrno = errno;
		msglog("%s sendto(%s%s%s.%d): %s", msg,
		       ifp != 0 ? ifp->int_name : "",
		       ifp != 0 ? ", " : "",
		       inet_ntoa(osin.sin_addr),
		       ntohs(osin.sin_port),
		       strerror(errno));
		errno = serrno;
	}

	return res;
}


/* Find the first key for a packet to send.
 * Try for a key that is eligible and has not expired, but settle for
 * the last key if they have all expired.
 * If no key is ready yet, give up.
 */
struct auth *
find_auth(struct interface *ifp)
{
	struct auth *ap, *res;
	int i;


	if (ifp == 0)
		return 0;

	res = 0;
	ap = ifp->int_auth;
	for (i = 0; i < MAX_AUTH_KEYS; i++, ap++) {
		/* stop looking after the last key */
		if (ap->type == RIP_AUTH_NONE)
			break;

		/* ignore keys that are not ready yet */
		if ((u_long)ap->start > (u_long)clk.tv_sec)
			continue;

		if ((u_long)ap->end < (u_long)clk.tv_sec) {
			/* note best expired password as a fall-back */
			if (res == 0 || (u_long)ap->end > (u_long)res->end)
				res = ap;
			continue;
		}

		/* note key with the best future */
		if (res == 0 || (u_long)res->end < (u_long)ap->end)
			res = ap;
	}
	return res;
}


void
clr_ws_buf(struct ws_buf *wb,
	   struct auth *ap)
{
	struct netauth *na;

	wb->lim = wb->base + NETS_LEN;
	wb->n = wb->base;
	memset(wb->n, 0, NETS_LEN*sizeof(*wb->n));

	/* (start to) install authentication if appropriate
	 */
	if (ap == 0)
		return;

	na = (struct netauth*)wb->n;
	if (ap->type == RIP_AUTH_PW) {
		na->a_family = RIP_AF_AUTH;
		na->a_type = RIP_AUTH_PW;
		memcpy(na->au.au_pw, ap->key, sizeof(na->au.au_pw));
		wb->n++;

	} else if (ap->type ==  RIP_AUTH_MD5) {
		na->a_family = RIP_AF_AUTH;
		na->a_type = RIP_AUTH_MD5;
		na->au.a_md5.md5_keyid = ap->keyid;
		na->au.a_md5.md5_auth_len = RIP_AUTH_MD5_KEY_LEN;
		na->au.a_md5.md5_seqno = htonl(clk.tv_sec);
		wb->n++;
		wb->lim--;		/* make room for trailer */
	}
}


void
end_md5_auth(struct ws_buf *wb,
	     struct auth *ap)
{
	struct netauth *na, *na2;
	MD5_CTX md5_ctx;
	int len;


	na = (struct netauth*)wb->base;
	na2 = (struct netauth*)wb->n;
	len = (char *)na2-(char *)wb->buf;
	na2->a_family = RIP_AF_AUTH;
	na2->a_type = htons(1);
	na->au.a_md5.md5_pkt_len = htons(len);
	MD5Init(&md5_ctx);
	MD5Update(&md5_ctx, (u_char *)wb->buf, len + RIP_AUTH_MD5_HASH_XTRA);
	MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_KEY_LEN);
	MD5Final(na2->au.au_pw, &md5_ctx);
	wb->n++;
}


/* Send the buffer
 */
static void
supply_write(struct ws_buf *wb)
{
	/* Output multicast only if legal.
	 * If we would multicast and it would be illegal, then discard the
	 * packet.
	 */
	switch (wb->type) {
	case NO_OUT_MULTICAST:
		trace_pkt("skip multicast to %s because impossible",
			  naddr_ntoa(ws.to.sin_addr.s_addr));
		break;
	case NO_OUT_RIPV2:
		break;
	default:
		if (ws.a != 0 && ws.a->type == RIP_AUTH_MD5)
			end_md5_auth(wb,ws.a);
		if (output(wb->type, &ws.to, ws.ifp, wb->buf,
			   ((char *)wb->n - (char*)wb->buf)) < 0
		    && ws.ifp != 0)
			if_sick(ws.ifp);
		ws.npackets++;
		break;
	}

	clr_ws_buf(wb,ws.a);
}


/* put an entry into the packet
 */
static void
supply_out(struct ag_info *ag)
{
	int i;
	naddr mask, v1_mask, dst_h, ddst_h = 0;
	struct ws_buf *wb;


	/* Skip this route if doing a flash update and it and the routes
	 * it aggregates have not changed recently.
	 */
	if (ag->ag_seqno < update_seqno
	    && (ws.state & WS_ST_FLASH))
		return;

	dst_h = ag->ag_dst_h;
	mask = ag->ag_mask;
	v1_mask = ripv1_mask_host(htonl(dst_h),
				  (ws.state & WS_ST_TO_ON_NET) ? ws.ifp : 0);
	i = 0;

	/* If we are sending RIPv2 packets that cannot (or must not) be
	 * heard by RIPv1 listeners, do not worry about sub- or supernets.
	 * Subnets (from other networks) can only be sent via multicast.
	 * A pair of subnet routes might have been promoted so that they
	 * are legal to send by RIPv1.
	 * If RIPv1 is off, use the multicast buffer.
	 */
	if ((ws.state & WS_ST_RIP2_ALL)
	    || ((ag->ag_state & AGS_RIPV2) && v1_mask != mask)) {
		/* use the RIPv2-only buffer */
		wb = &v2buf;

	} else {
		/* use the RIPv1-or-RIPv2 buffer */
		wb = &v12buf;

		/* Convert supernet route into corresponding set of network
		 * routes for RIPv1, but leave non-contiguous netmasks
		 * to ag_check().
		 */
		if (v1_mask > mask
		    && mask + (mask & -mask) == 0) {
			ddst_h = v1_mask & -v1_mask;
			i = (v1_mask & ~mask)/ddst_h;

			if (i > ws.gen_limit) {
				/* Punt if we would have to generate an
				 * unreasonable number of routes.
				 */
				if (TRACECONTENTS)
					trace_misc("sending %s-->%s as 1"
						   " instead of %d routes",
						   addrname(htonl(dst_h), mask,
							1),
						   naddr_ntoa(ws.to.sin_addr
							.s_addr),
						   i+1);
				i = 0;

			} else {
				mask = v1_mask;
				ws.gen_limit -= i;
			}
		}
	}

	do {
		wb->n->n_family = RIP_AF_INET;
		wb->n->n_dst = htonl(dst_h);
		/* If the route is from router-discovery or we are
		 * shutting down, admit only a bad metric.
		 */
		wb->n->n_metric = ((stopint || ag->ag_metric < 1)
				   ? HOPCNT_INFINITY
				   : ag->ag_metric);
		wb->n->n_metric = htonl(wb->n->n_metric);
		/* Any non-zero bits in the supposedly unused RIPv1 fields
		 * cause the old `routed` to ignore the route.
		 * That means the mask and so forth cannot be sent
		 * in the hybrid RIPv1/RIPv2 mode.
		 */
		if (ws.state & WS_ST_RIP2_ALL) {
			if (ag->ag_nhop != 0
			    && ((ws.state & WS_ST_QUERY)
				|| (ag->ag_nhop != ws.ifp->int_addr
				    && on_net(ag->ag_nhop,
					      ws.ifp->int_net,
					      ws.ifp->int_mask))))
				wb->n->n_nhop = ag->ag_nhop;
			wb->n->n_mask = htonl(mask);
			wb->n->n_tag = ag->ag_tag;
		}
		dst_h += ddst_h;

		if (++wb->n >= wb->lim)
			supply_write(wb);
	} while (i-- != 0);
}


/* supply one route from the table
 */
/* ARGSUSED */
static int
walk_supply(struct radix_node *rn,
	    struct walkarg *argp UNUSED)
{
#define RT ((struct rt_entry *)rn)
	u_short ags;
	char metric, pref;
	naddr dst, nhop;
	struct rt_spare *rts;
	int i;


	/* Do not advertise external remote interfaces or passive interfaces.
	 */
	if ((RT->rt_state & RS_IF)
	    && RT->rt_ifp != 0
	    && (RT->rt_ifp->int_state & IS_PASSIVE)
	    && !(RT->rt_state & RS_MHOME))
		return 0;

	/* If being quiet about our ability to forward, then
	 * do not say anything unless responding to a query,
	 * except about our main interface.
	 */
	if (!supplier && !(ws.state & WS_ST_QUERY)
	    && !(RT->rt_state & RS_MHOME))
		return 0;

	dst = RT->rt_dst;

	/* do not collide with the fake default route */
	if (dst == RIP_DEFAULT
	    && (ws.state & WS_ST_DEFAULT))
		return 0;

	if (RT->rt_state & RS_NET_SYN) {
		if (RT->rt_state & RS_NET_INT) {
			/* Do not send manual synthetic network routes
			 * into the subnet.
			 */
			if (on_net(ws.to.sin_addr.s_addr,
				   ntohl(dst), RT->rt_mask))
				return 0;

		} else {
			/* Do not send automatic synthetic network routes
			 * if they are not needed because no RIPv1 listeners
			 * can hear them.
			 */
			if (ws.state & WS_ST_RIP2_ALL)
				return 0;

			/* Do not send automatic synthetic network routes to
			 * the real subnet.
			 */
			if (on_net(ws.to.sin_addr.s_addr,
				   ntohl(dst), RT->rt_mask))
				return 0;
		}
		nhop = 0;

	} else {
		/* Advertise the next hop if this is not a route for one
		 * of our interfaces and the next hop is on the same
		 * network as the target.
		 * The final determination is made by supply_out().
		 */
		if (!(RT->rt_state & RS_IF)
		    && RT->rt_gate != myaddr
		    && RT->rt_gate != loopaddr)
			nhop = RT->rt_gate;
		else
			nhop = 0;
	}

	metric = RT->rt_metric;
	ags = 0;

	if (RT->rt_state & RS_MHOME) {
		/* retain host route of multi-homed servers */
		;

	} else if (RT_ISHOST(RT)) {
		/* We should always suppress (into existing network routes)
		 * the host routes for the local end of our point-to-point
		 * links.
		 * If we are suppressing host routes in general, then do so.
		 * Avoid advertising host routes onto their own network,
		 * where they should be handled by proxy-ARP.
		 */
		if ((RT->rt_state & RS_LOCAL)
		    || ridhosts
		    || on_net(dst, ws.to_net, ws.to_mask))
			ags |= AGS_SUPPRESS;

		/* Aggregate stray host routes into network routes if allowed.
		 * We cannot aggregate host routes into small network routes
		 * without confusing RIPv1 listeners into thinking the
		 * network routes are host routes.
		 */
		if ((ws.state & WS_ST_AG) && (ws.state & WS_ST_RIP2_ALL))
			ags |= AGS_AGGREGATE;

	} else {
		/* Always suppress network routes into other, existing
		 * network routes
		 */
		ags |= AGS_SUPPRESS;

		/* Generate supernets if allowed.
		 * If we can be heard by RIPv1 systems, we will
		 * later convert back to ordinary nets.
		 * This unifies dealing with received supernets.
		 */
		if ((ws.state & WS_ST_AG)
		    && ((RT->rt_state & RS_SUBNET)
			|| (ws.state & WS_ST_SUPER_AG)))
			ags |= AGS_AGGREGATE;
	}

	/* Do not send RIPv1 advertisements of subnets to other
	 * networks. If possible, multicast them by RIPv2.
	 */
	if ((RT->rt_state & RS_SUBNET)
	    && !(ws.state & WS_ST_RIP2_ALL)
	    && !on_net(dst, ws.to_std_net, ws.to_std_mask))
		ags |= AGS_RIPV2 | AGS_AGGREGATE;


	/* Do not send a route back to where it came from, except in
	 * response to a query.  This is "split-horizon".  That means not
	 * advertising back to the same network	and so via the same interface.
	 *
	 * We want to suppress routes that might have been fragmented
	 * from this route by a RIPv1 router and sent back to us, and so we
	 * cannot forget this route here.  Let the split-horizon route
	 * suppress the fragmented routes and then itself be forgotten.
	 *
	 * Include the routes for both ends of point-to-point interfaces
	 * among those suppressed by split-horizon, since the other side
	 * should knows them as well as we do.
	 *
	 * Notice spare routes with the same metric that we are about to
	 * advertise, to split the horizon on redundant, inactive paths.
	 *
	 * Do not suppress advertisements of interface-related addresses on
	 * non-point-to-point interfaces.  This ensures that we have something
	 * to say every 30 seconds to help detect broken Ethernets or
	 * other interfaces where one packet every 30 seconds costs nothing.
	 */
	if (ws.ifp != 0
	    && !(ws.state & WS_ST_QUERY)
	    && (ws.state & WS_ST_TO_ON_NET)
	    && (!(RT->rt_state & RS_IF)
		|| ws.ifp->int_if_flags & IFF_POINTOPOINT)) {
		for (rts = RT->rt_spares, i = NUM_SPARES; i != 0; i--, rts++) {
			if (rts->rts_metric > metric
			    || rts->rts_ifp != ws.ifp)
				continue;

			/* If we do not mark the route with AGS_SPLIT_HZ here,
			 * it will be poisoned-reverse, or advertised back
			 * toward its source with an infinite metric.
			 * If we have recently advertised the route with a
			 * better metric than we now have, then we should
			 * poison-reverse the route before suppressing it for
			 * split-horizon.
			 *
			 * In almost all cases, if there is no spare for the
			 * route then it is either old and dead or a brand
			 * new route. If it is brand new, there is no need
			 * for poison-reverse. If it is old and dead, it
			 * is already poisoned.
			 */
			if (RT->rt_poison_time < now_expire
			    || RT->rt_poison_metric >= metric
			    || RT->rt_spares[1].rts_gate == 0) {
				ags |= AGS_SPLIT_HZ;
				ags &= ~AGS_SUPPRESS;
			}
			metric = HOPCNT_INFINITY;
			break;
		}
	}

	/* Keep track of the best metric with which the
	 * route has been advertised recently.
	 */
	if (RT->rt_poison_metric >= metric
	    || RT->rt_poison_time < now_expire) {
		RT->rt_poison_time = now.tv_sec;
		RT->rt_poison_metric = metric;
	}

	/* Adjust the outgoing metric by the cost of the link.
	 * Avoid aggregation when a route is counting to infinity.
	 */
	pref = RT->rt_poison_metric + ws.metric;
	metric += ws.metric;

	/* Do not advertise stable routes that will be ignored,
	 * unless we are answering a query.
	 * If the route recently was advertised with a metric that
	 * would have been less than infinity through this interface,
	 * we need to continue to advertise it in order to poison it.
	 */
	if (metric >= HOPCNT_INFINITY) {
		if (!(ws.state & WS_ST_QUERY)
		    && (pref >= HOPCNT_INFINITY
			|| RT->rt_poison_time < now_garbage))
			return 0;

		metric = HOPCNT_INFINITY;
	}

	ag_check(dst, RT->rt_mask, 0, nhop, metric, pref,
		 RT->rt_seqno, RT->rt_tag, ags, supply_out);
	return 0;
#undef RT
}


/* Supply dst with the contents of the routing tables.
 * If this won't fit in one packet, chop it up into several.
 */
void
supply(struct sockaddr_in *dst,
       struct interface *ifp,		/* output interface */
       enum output_type type,
       int flash,			/* 1=flash update */
       int vers,			/* RIP version */
       int passwd_ok)			/* OK to include cleartext password */
{
	struct rt_entry *rt;
	int def_metric;


	ws.state = 0;
	ws.gen_limit = 1024;

	ws.to = *dst;
	ws.to_std_mask = std_mask(ws.to.sin_addr.s_addr);
	ws.to_std_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_std_mask;

	if (ifp != 0) {
		ws.to_mask = ifp->int_mask;
		ws.to_net = ifp->int_net;
		if (on_net(ws.to.sin_addr.s_addr, ws.to_net, ws.to_mask))
			ws.state |= WS_ST_TO_ON_NET;

	} else {
		ws.to_mask = ripv1_mask_net(ws.to.sin_addr.s_addr, 0);
		ws.to_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_mask;
		rt = rtfind(dst->sin_addr.s_addr);
		if (rt)
			ifp = rt->rt_ifp;
	}

	ws.npackets = 0;
	if (flash)
		ws.state |= WS_ST_FLASH;

	if ((ws.ifp = ifp) == 0) {
		ws.metric = 1;
	} else {
		/* Adjust the advertised metric by the outgoing interface
		 * metric.
		 */
		ws.metric = ifp->int_metric + 1 + ifp->int_adj_outmetric;
	}

	ripv12_buf.rip.rip_vers = vers;

	switch (type) {
	case OUT_MULTICAST:
		if (ifp->int_if_flags & IFF_MULTICAST)
			v2buf.type = OUT_MULTICAST;
		else
			v2buf.type = NO_OUT_MULTICAST;
		v12buf.type = OUT_BROADCAST;
		break;

	case OUT_QUERY:
		ws.state |= WS_ST_QUERY;
		/* FALLTHROUGH */
	case OUT_BROADCAST:
	case OUT_UNICAST:
		v2buf.type = (vers == RIPv2) ? type : NO_OUT_RIPV2;
		v12buf.type = type;
		break;

	case NO_OUT_MULTICAST:
	case NO_OUT_RIPV2:
		break;			/* no output */
	}

	if (vers == RIPv2) {
		/* full RIPv2 only if cannot be heard by RIPv1 listeners */
		if (type != OUT_BROADCAST)
			ws.state |= WS_ST_RIP2_ALL;
		if ((ws.state & WS_ST_QUERY)
		    || !(ws.state & WS_ST_TO_ON_NET)) {
			ws.state |= (WS_ST_AG | WS_ST_SUPER_AG);
		} else if (ifp == 0 || !(ifp->int_state & IS_NO_AG)) {
			ws.state |= WS_ST_AG;
			if (type != OUT_BROADCAST
			    && (ifp == 0
				|| !(ifp->int_state & IS_NO_SUPER_AG)))
				ws.state |= WS_ST_SUPER_AG;
		}
	}

	ws.a = (vers == RIPv2) ? find_auth(ifp) : 0;
	if (!passwd_ok && ws.a != 0 && ws.a->type == RIP_AUTH_PW)
		ws.a = 0;
	clr_ws_buf(&v12buf,ws.a);
	clr_ws_buf(&v2buf,ws.a);

	/*  Fake a default route if asked and if there is not already
	 * a better, real default route.
	 */
	if (supplier && (def_metric = ifp->int_d_metric) != 0) {
		if (0 == (rt = rtget(RIP_DEFAULT, 0))
		    || rt->rt_metric+ws.metric >= def_metric) {
			ws.state |= WS_ST_DEFAULT;
			ag_check(0, 0, 0, 0, def_metric, def_metric,
				 0, 0, 0, supply_out);
		} else {
			def_metric = rt->rt_metric+ws.metric;
		}

		/* If both RIPv2 and the poor-man's router discovery
		 * kludge are on, arrange to advertise an extra
		 * default route via RIPv1.
		 */
		if ((ws.state & WS_ST_RIP2_ALL)
		    && (ifp->int_state & IS_PM_RDISC)) {
			ripv12_buf.rip.rip_vers = RIPv1;
			v12buf.n->n_family = RIP_AF_INET;
			v12buf.n->n_dst = htonl(RIP_DEFAULT);
			v12buf.n->n_metric = htonl(def_metric);
			v12buf.n++;
		}
	}

	(void)rn_walktree(rhead, walk_supply, 0);
	ag_flush(0,0,supply_out);

	/* Flush the packet buffers, provided they are not empty and
	 * do not contain only the password.
	 */
	if (v12buf.n != v12buf.base
	    && (v12buf.n > v12buf.base+1
		|| v12buf.base->n_family != RIP_AF_AUTH))
		supply_write(&v12buf);
	if (v2buf.n != v2buf.base
	    && (v2buf.n > v2buf.base+1
		|| v2buf.base->n_family != RIP_AF_AUTH))
		supply_write(&v2buf);

	/* If we sent nothing and this is an answer to a query, send
	 * an empty buffer.
	 */
	if (ws.npackets == 0
	    && (ws.state & WS_ST_QUERY))
		supply_write(&v12buf);
}


/* send all of the routing table or just do a flash update
 */
void
rip_bcast(int flash)
{
#ifdef _HAVE_SIN_LEN
	static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
#else
	static struct sockaddr_in dst = {AF_INET};
#endif
	struct interface *ifp;
	enum output_type type;
	int vers;
	struct timeval rtime;


	need_flash = 0;
	intvl_random(&rtime, MIN_WAITTIME, MAX_WAITTIME);
	no_flash = rtime;
	timevaladd(&no_flash, &now);

	if (rip_sock < 0)
		return;

	trace_act("send %s and inhibit dynamic updates for %.3f sec",
		  flash ? "dynamic update" : "all routes",
		  rtime.tv_sec + ((float)rtime.tv_usec)/1000000.0);

	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
		/* Skip interfaces not doing RIP.
		 * Do try broken interfaces to see if they have healed.
		 */
		if (IS_RIP_OUT_OFF(ifp->int_state))
			continue;

		/* skip turned off interfaces */
		if (!iff_up(ifp->int_if_flags))
			continue;

		vers = (ifp->int_state & IS_NO_RIPV1_OUT) ? RIPv2 : RIPv1;

		if (ifp->int_if_flags & IFF_BROADCAST) {
			/* ordinary, hardware interface */
			dst.sin_addr.s_addr = ifp->int_brdaddr;

			if (vers == RIPv2
			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
				type = OUT_MULTICAST;
			} else {
				type = OUT_BROADCAST;
			}

		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
			/* point-to-point hardware interface */
			dst.sin_addr.s_addr = ifp->int_dstaddr;
			type = OUT_UNICAST;

		} else if (ifp->int_state & IS_REMOTE) {
			/* remote interface */
			dst.sin_addr.s_addr = ifp->int_addr;
			type = OUT_UNICAST;

		} else {
			/* ATM, HIPPI, etc. */
			continue;
		}

		supply(&dst, ifp, type, flash, vers, 1);
	}

	update_seqno++;			/* all routes are up to date */
}


/* Ask for routes
 * Do it only once to an interface, and not even after the interface
 * was broken and recovered.
 */
void
rip_query(void)
{
#ifdef _HAVE_SIN_LEN
	static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
#else
	static struct sockaddr_in dst = {AF_INET};
#endif
	struct interface *ifp;
	struct rip buf;
	enum output_type type;


	if (rip_sock < 0)
		return;

	memset(&buf, 0, sizeof(buf));

	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
		/* Skip interfaces those already queried.
		 * Do not ask via interfaces through which we don't
		 * accept input.  Do not ask via interfaces that cannot
		 * send RIP packets.
		 * Do try broken interfaces to see if they have healed.
		 */
		if (IS_RIP_IN_OFF(ifp->int_state)
		    || ifp->int_query_time != NEVER)
			continue;

		/* skip turned off interfaces */
		if (!iff_up(ifp->int_if_flags))
			continue;

		buf.rip_vers = (ifp->int_state&IS_NO_RIPV1_OUT) ? RIPv2:RIPv1;
		buf.rip_cmd = RIPCMD_REQUEST;
		buf.rip_nets[0].n_family = RIP_AF_UNSPEC;
		buf.rip_nets[0].n_metric = htonl(HOPCNT_INFINITY);

		/* Send a RIPv1 query only if allowed and if we will
		 * listen to RIPv1 routers.
		 */
		if ((ifp->int_state & IS_NO_RIPV1_OUT)
		    || (ifp->int_state & IS_NO_RIPV1_IN)) {
			buf.rip_vers = RIPv2;
		} else {
			buf.rip_vers = RIPv1;
		}

		if (ifp->int_if_flags & IFF_BROADCAST) {
			/* ordinary, hardware interface */
			dst.sin_addr.s_addr = ifp->int_brdaddr;

			/* Broadcast RIPv1 queries and RIPv2 queries
			 * when the hardware cannot multicast.
			 */
			if (buf.rip_vers == RIPv2
			    && (ifp->int_if_flags & IFF_MULTICAST)
			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
				type = OUT_MULTICAST;
			} else {
				type = OUT_BROADCAST;
			}

		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
			/* point-to-point hardware interface */
			dst.sin_addr.s_addr = ifp->int_dstaddr;
			type = OUT_UNICAST;

		} else if (ifp->int_state & IS_REMOTE) {
			/* remote interface */
			dst.sin_addr.s_addr = ifp->int_addr;
			type = OUT_UNICAST;

		} else {
			/* ATM, HIPPI, etc. */
			continue;
		}

		ifp->int_query_time = now.tv_sec+SUPPLY_INTERVAL;
		if (output(type, &dst, ifp, &buf, sizeof(buf)) < 0)
			if_sick(ifp);
	}
}
OpenPOWER on IntegriCloud