xref: /freebsd/sbin/routed/output.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  * $FreeBSD$
32  */
33 
34 #include "defs.h"
35 
36 #ifdef __NetBSD__
37 __RCSID("$NetBSD$");
38 #elif defined(__FreeBSD__)
39 __RCSID("$FreeBSD$");
40 #else
41 __RCSID("$Revision: 2.27 $");
42 #ident "$Revision: 2.27 $"
43 #endif
44 
45 
46 u_int update_seqno;
47 
48 
49 /* walk the tree of routes with this for output
50  */
51 static struct {
52 	struct sockaddr_in to;
53 	naddr	to_mask;
54 	naddr	to_net;
55 	naddr	to_std_mask;
56 	naddr	to_std_net;
57 	struct interface *ifp;		/* usually output interface */
58 	struct auth *a;
59 	char	metric;			/* adjust metrics by interface */
60 	int	npackets;
61 	int	gen_limit;
62 	u_int	state;
63 #define	    WS_ST_FLASH	    0x001	/* send only changed routes */
64 #define	    WS_ST_RIP2_ALL  0x002	/* send full featured RIPv2 */
65 #define	    WS_ST_AG	    0x004	/* ok to aggregate subnets */
66 #define	    WS_ST_SUPER_AG  0x008	/* ok to aggregate networks */
67 #define	    WS_ST_QUERY	    0x010	/* responding to a query */
68 #define	    WS_ST_TO_ON_NET 0x020	/* sending onto one of our nets */
69 #define	    WS_ST_DEFAULT   0x040	/* faking a default */
70 } ws;
71 
72 /* A buffer for what can be heard by both RIPv1 and RIPv2 listeners */
73 struct ws_buf v12buf;
74 static union pkt_buf ripv12_buf;
75 
76 /* Another for only RIPv2 listeners */
77 static struct ws_buf v2buf;
78 static union pkt_buf rip_v2_buf;
79 
80 
81 
82 void
83 bufinit(void)
84 {
85 	ripv12_buf.rip.rip_cmd = RIPCMD_RESPONSE;
86 	v12buf.buf = &ripv12_buf.rip;
87 	v12buf.base = &v12buf.buf->rip_nets[0];
88 
89 	rip_v2_buf.rip.rip_cmd = RIPCMD_RESPONSE;
90 	rip_v2_buf.rip.rip_vers = RIPv2;
91 	v2buf.buf = &rip_v2_buf.rip;
92 	v2buf.base = &v2buf.buf->rip_nets[0];
93 }
94 
95 
96 /* Send the contents of the global buffer via the non-multicast socket
97  */
98 int					/* <0 on failure */
99 output(enum output_type type,
100        struct sockaddr_in *dst,		/* send to here */
101        struct interface *ifp,
102        struct rip *buf,
103        int size)			/* this many bytes */
104 {
105 	struct sockaddr_in osin;
106 	int flags;
107 	const char *msg;
108 	int res;
109 	int soc;
110 	int serrno;
111 
112 	assert(ifp != NULL);
113 	osin = *dst;
114 	if (osin.sin_port == 0)
115 		osin.sin_port = htons(RIP_PORT);
116 #ifdef _HAVE_SIN_LEN
117 	if (osin.sin_len == 0)
118 		osin.sin_len = sizeof(osin);
119 #endif
120 
121 	soc = rip_sock;
122 	flags = 0;
123 
124 	switch (type) {
125 	case OUT_QUERY:
126 		msg = "Answer Query";
127 		if (soc < 0)
128 			soc = ifp->int_rip_sock;
129 		break;
130 	case OUT_UNICAST:
131 		msg = "Send";
132 		if (soc < 0)
133 			soc = ifp->int_rip_sock;
134 		flags = MSG_DONTROUTE;
135 		break;
136 	case OUT_BROADCAST:
137 		if (ifp->int_if_flags & IFF_POINTOPOINT) {
138 			msg = "Send";
139 		} else {
140 			msg = "Send bcast";
141 		}
142 		flags = MSG_DONTROUTE;
143 		break;
144 	case OUT_MULTICAST:
145 		if ((ifp->int_if_flags & (IFF_POINTOPOINT|IFF_MULTICAST)) ==
146 		    IFF_POINTOPOINT) {
147 			msg = "Send pt-to-pt";
148 		} else if (ifp->int_state & IS_DUP) {
149 			trace_act("abort multicast output via %s"
150 				  " with duplicate address",
151 				  ifp->int_name);
152 			return 0;
153 		} else {
154 			msg = "Send mcast";
155 			if (rip_sock_mcast != ifp) {
156 				struct ip_mreqn mreqn;
157 
158 				memset(&mreqn, 0, sizeof(struct ip_mreqn));
159 				mreqn.imr_ifindex = ifp->int_index;
160 				if (0 > setsockopt(rip_sock,
161 						   IPPROTO_IP,
162 						   IP_MULTICAST_IF,
163 						   &mreqn,
164 						   sizeof(mreqn))) {
165 					serrno = errno;
166 					LOGERR("setsockopt(rip_sock, "
167 					       "IP_MULTICAST_IF)");
168 					errno = serrno;
169 					ifp = NULL;
170 					return -1;
171 				}
172 				rip_sock_mcast = ifp;
173 			}
174 			osin.sin_addr.s_addr = htonl(INADDR_RIP_GROUP);
175 		}
176 		break;
177 
178 	case NO_OUT_MULTICAST:
179 	case NO_OUT_RIPV2:
180 	default:
181 #ifdef DEBUG
182 		abort();
183 #endif
184 		return -1;
185 	}
186 
187 	trace_rip(msg, "to", &osin, ifp, buf, size);
188 
189 	res = sendto(soc, buf, size, flags,
190 		     (struct sockaddr *)&osin, sizeof(osin));
191 	if (res < 0
192 	    && (ifp == NULL || !(ifp->int_state & IS_BROKE))) {
193 		serrno = errno;
194 		msglog("%s sendto(%s%s%s.%d): %s", msg,
195 		       ifp != NULL ? ifp->int_name : "",
196 		       ifp != NULL ? ", " : "",
197 		       inet_ntoa(osin.sin_addr),
198 		       ntohs(osin.sin_port),
199 		       strerror(errno));
200 		errno = serrno;
201 	}
202 
203 	return res;
204 }
205 
206 
207 /* Find the first key for a packet to send.
208  * Try for a key that is eligible and has not expired, but settle for
209  * the last key if they have all expired.
210  * If no key is ready yet, give up.
211  */
212 struct auth *
213 find_auth(struct interface *ifp)
214 {
215 	struct auth *ap, *res;
216 	int i;
217 
218 
219 	if (ifp == NULL)
220 		return 0;
221 
222 	res = NULL;
223 	ap = ifp->int_auth;
224 	for (i = 0; i < MAX_AUTH_KEYS; i++, ap++) {
225 		/* stop looking after the last key */
226 		if (ap->type == RIP_AUTH_NONE)
227 			break;
228 
229 		/* ignore keys that are not ready yet */
230 		if ((u_long)ap->start > (u_long)clk.tv_sec)
231 			continue;
232 
233 		if ((u_long)ap->end < (u_long)clk.tv_sec) {
234 			/* note best expired password as a fall-back */
235 			if (res == NULL || (u_long)ap->end > (u_long)res->end)
236 				res = ap;
237 			continue;
238 		}
239 
240 		/* note key with the best future */
241 		if (res == NULL || (u_long)res->end < (u_long)ap->end)
242 			res = ap;
243 	}
244 	return res;
245 }
246 
247 
248 void
249 clr_ws_buf(struct ws_buf *wb,
250 	   struct auth *ap)
251 {
252 	struct netauth *na;
253 
254 	wb->lim = wb->base + NETS_LEN;
255 	wb->n = wb->base;
256 	memset(wb->n, 0, NETS_LEN*sizeof(*wb->n));
257 
258 	/* (start to) install authentication if appropriate
259 	 */
260 	if (ap == NULL)
261 		return;
262 
263 	na = (struct netauth*)wb->n;
264 	if (ap->type == RIP_AUTH_PW) {
265 		na->a_family = RIP_AF_AUTH;
266 		na->a_type = RIP_AUTH_PW;
267 		memcpy(na->au.au_pw, ap->key, sizeof(na->au.au_pw));
268 		wb->n++;
269 
270 	} else if (ap->type ==  RIP_AUTH_MD5) {
271 		na->a_family = RIP_AF_AUTH;
272 		na->a_type = RIP_AUTH_MD5;
273 		na->au.a_md5.md5_keyid = ap->keyid;
274 		na->au.a_md5.md5_auth_len = RIP_AUTH_MD5_KEY_LEN;
275 		na->au.a_md5.md5_seqno = htonl(clk.tv_sec);
276 		wb->n++;
277 		wb->lim--;		/* make room for trailer */
278 	}
279 }
280 
281 
282 void
283 end_md5_auth(struct ws_buf *wb,
284 	     struct auth *ap)
285 {
286 	struct netauth *na, *na2;
287 	MD5_CTX md5_ctx;
288 	int len;
289 
290 
291 	na = (struct netauth*)wb->base;
292 	na2 = (struct netauth*)wb->n;
293 	len = (char *)na2-(char *)wb->buf;
294 	na2->a_family = RIP_AF_AUTH;
295 	na2->a_type = htons(1);
296 	na->au.a_md5.md5_pkt_len = htons(len);
297 	MD5Init(&md5_ctx);
298 	MD5Update(&md5_ctx, (u_char *)wb->buf, len + RIP_AUTH_MD5_HASH_XTRA);
299 	MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_KEY_LEN);
300 	MD5Final(na2->au.au_pw, &md5_ctx);
301 	wb->n++;
302 }
303 
304 
305 /* Send the buffer
306  */
307 static void
308 supply_write(struct ws_buf *wb)
309 {
310 	/* Output multicast only if legal.
311 	 * If we would multicast and it would be illegal, then discard the
312 	 * packet.
313 	 */
314 	switch (wb->type) {
315 	case NO_OUT_MULTICAST:
316 		trace_pkt("skip multicast to %s because impossible",
317 			  naddr_ntoa(ws.to.sin_addr.s_addr));
318 		break;
319 	case NO_OUT_RIPV2:
320 		break;
321 	default:
322 		if (ws.a != NULL && ws.a->type == RIP_AUTH_MD5)
323 			end_md5_auth(wb,ws.a);
324 		if (output(wb->type, &ws.to, ws.ifp, wb->buf,
325 			   ((char *)wb->n - (char*)wb->buf)) < 0
326 		    && ws.ifp != NULL)
327 			if_sick(ws.ifp);
328 		ws.npackets++;
329 		break;
330 	}
331 
332 	clr_ws_buf(wb,ws.a);
333 }
334 
335 
336 /* put an entry into the packet
337  */
338 static void
339 supply_out(struct ag_info *ag)
340 {
341 	int i;
342 	naddr mask, v1_mask, dst_h, ddst_h = 0;
343 	struct ws_buf *wb;
344 
345 
346 	/* Skip this route if doing a flash update and it and the routes
347 	 * it aggregates have not changed recently.
348 	 */
349 	if (ag->ag_seqno < update_seqno
350 	    && (ws.state & WS_ST_FLASH))
351 		return;
352 
353 	dst_h = ag->ag_dst_h;
354 	mask = ag->ag_mask;
355 	v1_mask = ripv1_mask_host(htonl(dst_h),
356 				  (ws.state & WS_ST_TO_ON_NET) ? ws.ifp : 0);
357 	i = 0;
358 
359 	/* If we are sending RIPv2 packets that cannot (or must not) be
360 	 * heard by RIPv1 listeners, do not worry about sub- or supernets.
361 	 * Subnets (from other networks) can only be sent via multicast.
362 	 * A pair of subnet routes might have been promoted so that they
363 	 * are legal to send by RIPv1.
364 	 * If RIPv1 is off, use the multicast buffer.
365 	 */
366 	if ((ws.state & WS_ST_RIP2_ALL)
367 	    || ((ag->ag_state & AGS_RIPV2) && v1_mask != mask)) {
368 		/* use the RIPv2-only buffer */
369 		wb = &v2buf;
370 
371 	} else {
372 		/* use the RIPv1-or-RIPv2 buffer */
373 		wb = &v12buf;
374 
375 		/* Convert supernet route into corresponding set of network
376 		 * routes for RIPv1, but leave non-contiguous netmasks
377 		 * to ag_check().
378 		 */
379 		if (v1_mask > mask
380 		    && mask + (mask & -mask) == 0) {
381 			ddst_h = v1_mask & -v1_mask;
382 			i = (v1_mask & ~mask)/ddst_h;
383 
384 			if (i > ws.gen_limit) {
385 				/* Punt if we would have to generate an
386 				 * unreasonable number of routes.
387 				 */
388 				if (TRACECONTENTS)
389 					trace_misc("sending %s-->%s as 1"
390 						   " instead of %d routes",
391 						   addrname(htonl(dst_h), mask,
392 							1),
393 						   naddr_ntoa(ws.to.sin_addr
394 							.s_addr),
395 						   i+1);
396 				i = 0;
397 
398 			} else {
399 				mask = v1_mask;
400 				ws.gen_limit -= i;
401 			}
402 		}
403 	}
404 
405 	do {
406 		wb->n->n_family = RIP_AF_INET;
407 		wb->n->n_dst = htonl(dst_h);
408 		/* If the route is from router-discovery or we are
409 		 * shutting down, admit only a bad metric.
410 		 */
411 		wb->n->n_metric = ((stopint || ag->ag_metric < 1)
412 				   ? HOPCNT_INFINITY
413 				   : ag->ag_metric);
414 		wb->n->n_metric = htonl(wb->n->n_metric);
415 		/* Any non-zero bits in the supposedly unused RIPv1 fields
416 		 * cause the old `routed` to ignore the route.
417 		 * That means the mask and so forth cannot be sent
418 		 * in the hybrid RIPv1/RIPv2 mode.
419 		 */
420 		if (ws.state & WS_ST_RIP2_ALL) {
421 			if (ag->ag_nhop != 0
422 			    && ((ws.state & WS_ST_QUERY)
423 				|| (ag->ag_nhop != ws.ifp->int_addr
424 				    && on_net(ag->ag_nhop,
425 					      ws.ifp->int_net,
426 					      ws.ifp->int_mask))))
427 				wb->n->n_nhop = ag->ag_nhop;
428 			wb->n->n_mask = htonl(mask);
429 			wb->n->n_tag = ag->ag_tag;
430 		}
431 		dst_h += ddst_h;
432 
433 		if (++wb->n >= wb->lim)
434 			supply_write(wb);
435 	} while (i-- != 0);
436 }
437 
438 
439 /* supply one route from the table
440  */
441 /* ARGSUSED */
442 static int
443 walk_supply(struct radix_node *rn,
444 	    struct walkarg *argp UNUSED)
445 {
446 #define RT ((struct rt_entry *)rn)
447 	u_short ags;
448 	char metric, pref;
449 	naddr dst, nhop;
450 	struct rt_spare *rts;
451 	int i;
452 
453 
454 	/* Do not advertise external remote interfaces or passive interfaces.
455 	 */
456 	if ((RT->rt_state & RS_IF)
457 	    && RT->rt_ifp != 0
458 	    && (RT->rt_ifp->int_state & IS_PASSIVE)
459 	    && !(RT->rt_state & RS_MHOME))
460 		return 0;
461 
462 	/* If being quiet about our ability to forward, then
463 	 * do not say anything unless responding to a query,
464 	 * except about our main interface.
465 	 */
466 	if (!supplier && !(ws.state & WS_ST_QUERY)
467 	    && !(RT->rt_state & RS_MHOME))
468 		return 0;
469 
470 	dst = RT->rt_dst;
471 
472 	/* do not collide with the fake default route */
473 	if (dst == RIP_DEFAULT
474 	    && (ws.state & WS_ST_DEFAULT))
475 		return 0;
476 
477 	if (RT->rt_state & RS_NET_SYN) {
478 		if (RT->rt_state & RS_NET_INT) {
479 			/* Do not send manual synthetic network routes
480 			 * into the subnet.
481 			 */
482 			if (on_net(ws.to.sin_addr.s_addr,
483 				   ntohl(dst), RT->rt_mask))
484 				return 0;
485 
486 		} else {
487 			/* Do not send automatic synthetic network routes
488 			 * if they are not needed because no RIPv1 listeners
489 			 * can hear them.
490 			 */
491 			if (ws.state & WS_ST_RIP2_ALL)
492 				return 0;
493 
494 			/* Do not send automatic synthetic network routes to
495 			 * the real subnet.
496 			 */
497 			if (on_net(ws.to.sin_addr.s_addr,
498 				   ntohl(dst), RT->rt_mask))
499 				return 0;
500 		}
501 		nhop = 0;
502 
503 	} else {
504 		/* Advertise the next hop if this is not a route for one
505 		 * of our interfaces and the next hop is on the same
506 		 * network as the target.
507 		 * The final determination is made by supply_out().
508 		 */
509 		if (!(RT->rt_state & RS_IF)
510 		    && RT->rt_gate != myaddr
511 		    && RT->rt_gate != loopaddr)
512 			nhop = RT->rt_gate;
513 		else
514 			nhop = 0;
515 	}
516 
517 	metric = RT->rt_metric;
518 	ags = 0;
519 
520 	if (RT->rt_state & RS_MHOME) {
521 		/* retain host route of multi-homed servers */
522 		;
523 
524 	} else if (RT_ISHOST(RT)) {
525 		/* We should always suppress (into existing network routes)
526 		 * the host routes for the local end of our point-to-point
527 		 * links.
528 		 * If we are suppressing host routes in general, then do so.
529 		 * Avoid advertising host routes onto their own network,
530 		 * where they should be handled by proxy-ARP.
531 		 */
532 		if ((RT->rt_state & RS_LOCAL)
533 		    || ridhosts
534 		    || on_net(dst, ws.to_net, ws.to_mask))
535 			ags |= AGS_SUPPRESS;
536 
537 		/* Aggregate stray host routes into network routes if allowed.
538 		 * We cannot aggregate host routes into small network routes
539 		 * without confusing RIPv1 listeners into thinking the
540 		 * network routes are host routes.
541 		 */
542 		if ((ws.state & WS_ST_AG) && (ws.state & WS_ST_RIP2_ALL))
543 			ags |= AGS_AGGREGATE;
544 
545 	} else {
546 		/* Always suppress network routes into other, existing
547 		 * network routes
548 		 */
549 		ags |= AGS_SUPPRESS;
550 
551 		/* Generate supernets if allowed.
552 		 * If we can be heard by RIPv1 systems, we will
553 		 * later convert back to ordinary nets.
554 		 * This unifies dealing with received supernets.
555 		 */
556 		if ((ws.state & WS_ST_AG)
557 		    && ((RT->rt_state & RS_SUBNET)
558 			|| (ws.state & WS_ST_SUPER_AG)))
559 			ags |= AGS_AGGREGATE;
560 	}
561 
562 	/* Do not send RIPv1 advertisements of subnets to other
563 	 * networks. If possible, multicast them by RIPv2.
564 	 */
565 	if ((RT->rt_state & RS_SUBNET)
566 	    && !(ws.state & WS_ST_RIP2_ALL)
567 	    && !on_net(dst, ws.to_std_net, ws.to_std_mask))
568 		ags |= AGS_RIPV2 | AGS_AGGREGATE;
569 
570 
571 	/* Do not send a route back to where it came from, except in
572 	 * response to a query.  This is "split-horizon".  That means not
573 	 * advertising back to the same network	and so via the same interface.
574 	 *
575 	 * We want to suppress routes that might have been fragmented
576 	 * from this route by a RIPv1 router and sent back to us, and so we
577 	 * cannot forget this route here.  Let the split-horizon route
578 	 * suppress the fragmented routes and then itself be forgotten.
579 	 *
580 	 * Include the routes for both ends of point-to-point interfaces
581 	 * among those suppressed by split-horizon, since the other side
582 	 * should knows them as well as we do.
583 	 *
584 	 * Notice spare routes with the same metric that we are about to
585 	 * advertise, to split the horizon on redundant, inactive paths.
586 	 *
587 	 * Do not suppress advertisements of interface-related addresses on
588 	 * non-point-to-point interfaces.  This ensures that we have something
589 	 * to say every 30 seconds to help detect broken Ethernets or
590 	 * other interfaces where one packet every 30 seconds costs nothing.
591 	 */
592 	if (ws.ifp != NULL
593 	    && !(ws.state & WS_ST_QUERY)
594 	    && (ws.state & WS_ST_TO_ON_NET)
595 	    && (!(RT->rt_state & RS_IF)
596 		|| ws.ifp->int_if_flags & IFF_POINTOPOINT)) {
597 		for (rts = RT->rt_spares, i = NUM_SPARES; i != 0; i--, rts++) {
598 			if (rts->rts_metric > metric
599 			    || rts->rts_ifp != ws.ifp)
600 				continue;
601 
602 			/* If we do not mark the route with AGS_SPLIT_HZ here,
603 			 * it will be poisoned-reverse, or advertised back
604 			 * toward its source with an infinite metric.
605 			 * If we have recently advertised the route with a
606 			 * better metric than we now have, then we should
607 			 * poison-reverse the route before suppressing it for
608 			 * split-horizon.
609 			 *
610 			 * In almost all cases, if there is no spare for the
611 			 * route then it is either old and dead or a brand
612 			 * new route. If it is brand new, there is no need
613 			 * for poison-reverse. If it is old and dead, it
614 			 * is already poisoned.
615 			 */
616 			if (RT->rt_poison_time < now_expire
617 			    || RT->rt_poison_metric >= metric
618 			    || RT->rt_spares[1].rts_gate == 0) {
619 				ags |= AGS_SPLIT_HZ;
620 				ags &= ~AGS_SUPPRESS;
621 			}
622 			metric = HOPCNT_INFINITY;
623 			break;
624 		}
625 	}
626 
627 	/* Keep track of the best metric with which the
628 	 * route has been advertised recently.
629 	 */
630 	if (RT->rt_poison_metric >= metric
631 	    || RT->rt_poison_time < now_expire) {
632 		RT->rt_poison_time = now.tv_sec;
633 		RT->rt_poison_metric = metric;
634 	}
635 
636 	/* Adjust the outgoing metric by the cost of the link.
637 	 * Avoid aggregation when a route is counting to infinity.
638 	 */
639 	pref = RT->rt_poison_metric + ws.metric;
640 	metric += ws.metric;
641 
642 	/* Do not advertise stable routes that will be ignored,
643 	 * unless we are answering a query.
644 	 * If the route recently was advertised with a metric that
645 	 * would have been less than infinity through this interface,
646 	 * we need to continue to advertise it in order to poison it.
647 	 */
648 	if (metric >= HOPCNT_INFINITY) {
649 		if (!(ws.state & WS_ST_QUERY)
650 		    && (pref >= HOPCNT_INFINITY
651 			|| RT->rt_poison_time < now_garbage))
652 			return 0;
653 
654 		metric = HOPCNT_INFINITY;
655 	}
656 
657 	ag_check(dst, RT->rt_mask, 0, nhop, metric, pref,
658 		 RT->rt_seqno, RT->rt_tag, ags, supply_out);
659 	return 0;
660 #undef RT
661 }
662 
663 
664 /* Supply dst with the contents of the routing tables.
665  * If this won't fit in one packet, chop it up into several.
666  */
667 void
668 supply(struct sockaddr_in *dst,
669        struct interface *ifp,		/* output interface */
670        enum output_type type,
671        int flash,			/* 1=flash update */
672        int vers,			/* RIP version */
673        int passwd_ok)			/* OK to include cleartext password */
674 {
675 	struct rt_entry *rt;
676 	int def_metric;
677 
678 	ws.state = 0;
679 	ws.gen_limit = 1024;
680 
681 	ws.to = *dst;
682 	ws.to_std_mask = std_mask(ws.to.sin_addr.s_addr);
683 	ws.to_std_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_std_mask;
684 
685 	if (ifp != NULL) {
686 		ws.to_mask = ifp->int_mask;
687 		ws.to_net = ifp->int_net;
688 		if (on_net(ws.to.sin_addr.s_addr, ws.to_net, ws.to_mask))
689 			ws.state |= WS_ST_TO_ON_NET;
690 
691 	} else {
692 		ws.to_mask = ripv1_mask_net(ws.to.sin_addr.s_addr, 0);
693 		ws.to_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_mask;
694 		rt = rtfind(dst->sin_addr.s_addr);
695 		if (rt)
696 			ifp = rt->rt_ifp;
697 	}
698 
699 	ws.npackets = 0;
700 	if (flash)
701 		ws.state |= WS_ST_FLASH;
702 
703 	if ((ws.ifp = ifp) == NULL) {
704 		ws.metric = 1;
705 	} else {
706 		/* Adjust the advertised metric by the outgoing interface
707 		 * metric.
708 		 */
709 		ws.metric = ifp->int_metric + 1 + ifp->int_adj_outmetric;
710 	}
711 
712 	ripv12_buf.rip.rip_vers = vers;
713 
714 	switch (type) {
715 	case OUT_MULTICAST:
716 		if (ifp != NULL && ifp->int_if_flags & IFF_MULTICAST)
717 			v2buf.type = OUT_MULTICAST;
718 		else
719 			v2buf.type = NO_OUT_MULTICAST;
720 		v12buf.type = OUT_BROADCAST;
721 		break;
722 
723 	case OUT_QUERY:
724 		ws.state |= WS_ST_QUERY;
725 		/* FALLTHROUGH */
726 	case OUT_BROADCAST:
727 	case OUT_UNICAST:
728 		v2buf.type = (vers == RIPv2) ? type : NO_OUT_RIPV2;
729 		v12buf.type = type;
730 		break;
731 
732 	case NO_OUT_MULTICAST:
733 	case NO_OUT_RIPV2:
734 		break;			/* no output */
735 	}
736 
737 	if (vers == RIPv2) {
738 		/* full RIPv2 only if cannot be heard by RIPv1 listeners */
739 		if (type != OUT_BROADCAST)
740 			ws.state |= WS_ST_RIP2_ALL;
741 		if ((ws.state & WS_ST_QUERY)
742 		    || !(ws.state & WS_ST_TO_ON_NET)) {
743 			ws.state |= (WS_ST_AG | WS_ST_SUPER_AG);
744 		} else if (ifp == NULL || !(ifp->int_state & IS_NO_AG)) {
745 			ws.state |= WS_ST_AG;
746 			if (type != OUT_BROADCAST
747 			    && (ifp == NULL
748 				|| !(ifp->int_state & IS_NO_SUPER_AG)))
749 				ws.state |= WS_ST_SUPER_AG;
750 		}
751 	}
752 
753 	ws.a = (vers == RIPv2) ? find_auth(ifp) : 0;
754 	if (!passwd_ok && ws.a != NULL && ws.a->type == RIP_AUTH_PW)
755 		ws.a = NULL;
756 	clr_ws_buf(&v12buf,ws.a);
757 	clr_ws_buf(&v2buf,ws.a);
758 
759 	/*  Fake a default route if asked and if there is not already
760 	 * a better, real default route.
761 	 */
762 	if (supplier && ifp && (def_metric = ifp->int_d_metric) != 0) {
763 		if ((rt = rtget(RIP_DEFAULT, 0)) == NULL
764 		    || rt->rt_metric+ws.metric >= def_metric) {
765 			ws.state |= WS_ST_DEFAULT;
766 			ag_check(0, 0, 0, 0, def_metric, def_metric,
767 				 0, 0, 0, supply_out);
768 		} else {
769 			def_metric = rt->rt_metric+ws.metric;
770 		}
771 
772 		/* If both RIPv2 and the poor-man's router discovery
773 		 * kludge are on, arrange to advertise an extra
774 		 * default route via RIPv1.
775 		 */
776 		if ((ws.state & WS_ST_RIP2_ALL)
777 		    && (ifp->int_state & IS_PM_RDISC)) {
778 			ripv12_buf.rip.rip_vers = RIPv1;
779 			v12buf.n->n_family = RIP_AF_INET;
780 			v12buf.n->n_dst = htonl(RIP_DEFAULT);
781 			v12buf.n->n_metric = htonl(def_metric);
782 			v12buf.n++;
783 		}
784 	}
785 
786 	(void)rn_walktree(rhead, walk_supply, 0);
787 	ag_flush(0,0,supply_out);
788 
789 	/* Flush the packet buffers, provided they are not empty and
790 	 * do not contain only the password.
791 	 */
792 	if (v12buf.n != v12buf.base
793 	    && (v12buf.n > v12buf.base+1
794 		|| v12buf.base->n_family != RIP_AF_AUTH))
795 		supply_write(&v12buf);
796 	if (v2buf.n != v2buf.base
797 	    && (v2buf.n > v2buf.base+1
798 		|| v2buf.base->n_family != RIP_AF_AUTH))
799 		supply_write(&v2buf);
800 
801 	/* If we sent nothing and this is an answer to a query, send
802 	 * an empty buffer.
803 	 */
804 	if (ws.npackets == 0
805 	    && (ws.state & WS_ST_QUERY))
806 		supply_write(&v12buf);
807 }
808 
809 
810 /* send all of the routing table or just do a flash update
811  */
812 void
813 rip_bcast(int flash)
814 {
815 #ifdef _HAVE_SIN_LEN
816 	static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
817 #else
818 	static struct sockaddr_in dst = {AF_INET};
819 #endif
820 	struct interface *ifp;
821 	enum output_type type;
822 	int vers;
823 	struct timeval rtime;
824 
825 
826 	need_flash = 0;
827 	intvl_random(&rtime, MIN_WAITTIME, MAX_WAITTIME);
828 	no_flash = rtime;
829 	timevaladd(&no_flash, &now);
830 
831 	if (rip_sock < 0)
832 		return;
833 
834 	trace_act("send %s and inhibit dynamic updates for %.3f sec",
835 		  flash ? "dynamic update" : "all routes",
836 		  rtime.tv_sec + ((float)rtime.tv_usec)/1000000.0);
837 
838 	LIST_FOREACH(ifp, &ifnet, int_list) {
839 		/* Skip interfaces not doing RIP.
840 		 * Do try broken interfaces to see if they have healed.
841 		 */
842 		if (IS_RIP_OUT_OFF(ifp->int_state))
843 			continue;
844 
845 		/* skip turned off interfaces */
846 		if (!iff_up(ifp->int_if_flags))
847 			continue;
848 
849 		vers = (ifp->int_state & IS_NO_RIPV1_OUT) ? RIPv2 : RIPv1;
850 
851 		if (ifp->int_if_flags & IFF_BROADCAST) {
852 			/* ordinary, hardware interface */
853 			dst.sin_addr.s_addr = ifp->int_brdaddr;
854 
855 			if (vers == RIPv2
856 			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
857 				type = OUT_MULTICAST;
858 			} else {
859 				type = OUT_BROADCAST;
860 			}
861 
862 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
863 			/* point-to-point hardware interface */
864 			dst.sin_addr.s_addr = ifp->int_dstaddr;
865 			if (vers == RIPv2 &&
866 			    ifp->int_if_flags & IFF_MULTICAST &&
867 			    !(ifp->int_state  & IS_NO_RIP_MCAST)) {
868 				type = OUT_MULTICAST;
869 			} else {
870 				type = OUT_UNICAST;
871 			}
872 
873 		} else if (ifp->int_state & IS_REMOTE) {
874 			/* remote interface */
875 			dst.sin_addr.s_addr = ifp->int_addr;
876 			type = OUT_UNICAST;
877 
878 		} else {
879 			/* ATM, HIPPI, etc. */
880 			continue;
881 		}
882 
883 		supply(&dst, ifp, type, flash, vers, 1);
884 	}
885 
886 	update_seqno++;			/* all routes are up to date */
887 }
888 
889 
890 /* Ask for routes
891  * Do it only once to an interface, and not even after the interface
892  * was broken and recovered.
893  */
894 void
895 rip_query(void)
896 {
897 #ifdef _HAVE_SIN_LEN
898 	static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
899 #else
900 	static struct sockaddr_in dst = {AF_INET};
901 #endif
902 	struct interface *ifp;
903 	struct rip buf;
904 	enum output_type type;
905 
906 
907 	if (rip_sock < 0)
908 		return;
909 
910 	memset(&buf, 0, sizeof(buf));
911 
912 	LIST_FOREACH(ifp, &ifnet, int_list) {
913 		/* Skip interfaces those already queried.
914 		 * Do not ask via interfaces through which we don't
915 		 * accept input.  Do not ask via interfaces that cannot
916 		 * send RIP packets.
917 		 * Do try broken interfaces to see if they have healed.
918 		 */
919 		if (IS_RIP_IN_OFF(ifp->int_state)
920 		    || ifp->int_query_time != NEVER)
921 			continue;
922 
923 		/* skip turned off interfaces */
924 		if (!iff_up(ifp->int_if_flags))
925 			continue;
926 
927 		buf.rip_vers = (ifp->int_state&IS_NO_RIPV1_OUT) ? RIPv2:RIPv1;
928 		buf.rip_cmd = RIPCMD_REQUEST;
929 		buf.rip_nets[0].n_family = RIP_AF_UNSPEC;
930 		buf.rip_nets[0].n_metric = htonl(HOPCNT_INFINITY);
931 
932 		/* Send a RIPv1 query only if allowed and if we will
933 		 * listen to RIPv1 routers.
934 		 */
935 		if ((ifp->int_state & IS_NO_RIPV1_OUT)
936 		    || (ifp->int_state & IS_NO_RIPV1_IN)) {
937 			buf.rip_vers = RIPv2;
938 		} else {
939 			buf.rip_vers = RIPv1;
940 		}
941 
942 		if (ifp->int_if_flags & IFF_BROADCAST) {
943 			/* ordinary, hardware interface */
944 			dst.sin_addr.s_addr = ifp->int_brdaddr;
945 
946 			/* Broadcast RIPv1 queries and RIPv2 queries
947 			 * when the hardware cannot multicast.
948 			 */
949 			if (buf.rip_vers == RIPv2
950 			    && (ifp->int_if_flags & IFF_MULTICAST)
951 			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
952 				type = OUT_MULTICAST;
953 			} else {
954 				type = OUT_BROADCAST;
955 			}
956 
957 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
958 			/* point-to-point hardware interface */
959 			dst.sin_addr.s_addr = ifp->int_dstaddr;
960 			type = OUT_UNICAST;
961 
962 		} else if (ifp->int_state & IS_REMOTE) {
963 			/* remote interface */
964 			dst.sin_addr.s_addr = ifp->int_addr;
965 			type = OUT_UNICAST;
966 
967 		} else {
968 			/* ATM, HIPPI, etc. */
969 			continue;
970 		}
971 
972 		ifp->int_query_time = now.tv_sec+SUPPLY_INTERVAL;
973 		if (output(type, &dst, ifp, &buf, sizeof(buf)) < 0)
974 			if_sick(ifp);
975 	}
976 }
977