xref: /netbsd/sbin/routed/output.c (revision bf9ec67e)
1 /*	$NetBSD: output.c,v 1.21 2001/11/02 05:30:56 lukem Exp $	*/
2 
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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgment:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include "defs.h"
37 
38 #ifdef __NetBSD__
39 __RCSID("$NetBSD: output.c,v 1.21 2001/11/02 05:30:56 lukem Exp $");
40 #elif defined(__FreeBSD__)
41 __RCSID("$FreeBSD$");
42 #else
43 __RCSID("Revision: 2.23 ");
44 #ident "Revision: 2.23 "
45 #endif
46 
47 
48 u_int update_seqno;
49 
50 
51 /* walk the tree of routes with this for output
52  */
53 struct {
54 	struct sockaddr_in to;
55 	naddr	to_mask;
56 	naddr	to_net;
57 	naddr	to_std_mask;
58 	naddr	to_std_net;
59 	struct interface *ifp;		/* usually output interface */
60 	struct auth *a;
61 	char	metric;			/* adjust metrics by interface */
62 	int	npackets;
63 	int	gen_limit;
64 	u_int	state;
65 #define	    WS_ST_FLASH	    0x001	/* send only changed routes */
66 #define	    WS_ST_RIP2_ALL  0x002	/* send full featured RIPv2 */
67 #define	    WS_ST_AG	    0x004	/* ok to aggregate subnets */
68 #define	    WS_ST_SUPER_AG  0x008	/* ok to aggregate networks */
69 #define	    WS_ST_QUERY	    0x010	/* responding to a query */
70 #define	    WS_ST_TO_ON_NET 0x020	/* sending onto one of our nets */
71 #define	    WS_ST_DEFAULT   0x040	/* faking a default */
72 } ws;
73 
74 /* A buffer for what can be heard by both RIPv1 and RIPv2 listeners */
75 struct ws_buf v12buf;
76 union pkt_buf ripv12_buf;
77 
78 /* Another for only RIPv2 listeners */
79 struct ws_buf v2buf;
80 union pkt_buf rip_v2_buf;
81 
82 
83 
84 void
85 bufinit(void)
86 {
87 	ripv12_buf.rip.rip_cmd = RIPCMD_RESPONSE;
88 	v12buf.buf = &ripv12_buf.rip;
89 	v12buf.base = &v12buf.buf->rip_nets[0];
90 
91 	rip_v2_buf.rip.rip_cmd = RIPCMD_RESPONSE;
92 	rip_v2_buf.rip.rip_vers = RIPv2;
93 	v2buf.buf = &rip_v2_buf.rip;
94 	v2buf.base = &v2buf.buf->rip_nets[0];
95 }
96 
97 
98 /* Send the contents of the global buffer via the non-multicast socket
99  */
100 int					/* <0 on failure */
101 output(enum output_type type,
102        struct sockaddr_in *dst,		/* send to here */
103        struct interface *ifp,
104        struct rip *buf,
105        int size)			/* this many bytes */
106 {
107 	struct sockaddr_in osin;
108 	int flags;
109 	const char *msg;
110 	int res;
111 	naddr tgt_mcast;
112 	int soc;
113 	int serrno;
114 
115 	osin = *dst;
116 	if (osin.sin_port == 0)
117 		osin.sin_port = htons(RIP_PORT);
118 #ifdef _HAVE_SIN_LEN
119 	if (osin.sin_len == 0)
120 		osin.sin_len = sizeof(osin);
121 #endif
122 
123 	soc = rip_sock;
124 	flags = 0;
125 
126 	switch (type) {
127 	case OUT_QUERY:
128 		msg = "Answer Query";
129 		if (soc < 0)
130 			soc = ifp->int_rip_sock;
131 		break;
132 	case OUT_UNICAST:
133 		msg = "Send";
134 		if (soc < 0)
135 			soc = ifp->int_rip_sock;
136 		flags = MSG_DONTROUTE;
137 		break;
138 	case OUT_BROADCAST:
139 		if (ifp->int_if_flags & IFF_POINTOPOINT) {
140 			msg = "Send";
141 		} else {
142 			msg = "Send bcast";
143 		}
144 		flags = MSG_DONTROUTE;
145 		break;
146 	case OUT_MULTICAST:
147 		if (ifp->int_if_flags & IFF_POINTOPOINT) {
148 			msg = "Send pt-to-pt";
149 		} else if (ifp->int_state & IS_DUP) {
150 			trace_act("abort multicast output via %s"
151 				  " with duplicate address",
152 				  ifp->int_name);
153 			return 0;
154 		} else {
155 			msg = "Send mcast";
156 			if (rip_sock_mcast != ifp) {
157 #ifdef MCAST_IFINDEX
158 				/* specify ifindex */
159 				tgt_mcast = htonl(ifp->int_index);
160 #else
161 #ifdef MCAST_PPP_BUG
162 				/* Do not specify the primary interface
163 				 * explicitly if we have the multicast
164 				 * point-to-point kernel bug, since the
165 				 * kernel will do the wrong thing if the
166 				 * local address of a point-to-point link
167 				 * is the same as the address of an ordinary
168 				 * interface.
169 				 */
170 				if (ifp->int_addr == myaddr) {
171 					tgt_mcast = 0;
172 				} else
173 #endif
174 				tgt_mcast = ifp->int_addr;
175 #endif
176 				if (0 > setsockopt(rip_sock,
177 						   IPPROTO_IP, IP_MULTICAST_IF,
178 						   &tgt_mcast,
179 						   sizeof(tgt_mcast))) {
180 					serrno = errno;
181 					LOGERR("setsockopt(rip_sock,"
182 					       "IP_MULTICAST_IF)");
183 					errno = serrno;
184 					ifp = 0;
185 					return -1;
186 				}
187 				rip_sock_mcast = ifp;
188 			}
189 			osin.sin_addr.s_addr = htonl(INADDR_RIP_GROUP);
190 		}
191 		break;
192 
193 	case NO_OUT_MULTICAST:
194 	case NO_OUT_RIPV2:
195 	default:
196 #ifdef DEBUG
197 		abort();
198 #endif
199 		return -1;
200 	}
201 
202 	trace_rip(msg, "to", &osin, ifp, buf, size);
203 
204 	res = sendto(soc, buf, size, flags,
205 		     (struct sockaddr *)&osin, sizeof(osin));
206 	if (res < 0
207 	    && (ifp == 0 || !(ifp->int_state & IS_BROKE))) {
208 		serrno = errno;
209 		msglog("%s sendto(%s%s%s.%d): %s", msg,
210 		       ifp != 0 ? ifp->int_name : "",
211 		       ifp != 0 ? ", " : "",
212 		       inet_ntoa(osin.sin_addr),
213 		       ntohs(osin.sin_port),
214 		       strerror(errno));
215 		errno = serrno;
216 	}
217 
218 	return res;
219 }
220 
221 
222 /* Find the first key for a packet to send.
223  * Try for a key that is eligible and has not expired, but settle for
224  * the last key if they have all expired.
225  * If no key is ready yet, give up.
226  */
227 struct auth *
228 find_auth(struct interface *ifp)
229 {
230 	struct auth *ap, *res;
231 	int i;
232 
233 
234 	if (ifp == 0)
235 		return 0;
236 
237 	res = 0;
238 	ap = ifp->int_auth;
239 	for (i = 0; i < MAX_AUTH_KEYS; i++, ap++) {
240 		/* stop looking after the last key */
241 		if (ap->type == RIP_AUTH_NONE)
242 			break;
243 
244 		/* ignore keys that are not ready yet */
245 		if ((u_long)ap->start > (u_long)clk.tv_sec)
246 			continue;
247 
248 		if ((u_long)ap->end < (u_long)clk.tv_sec) {
249 			/* note best expired password as a fall-back */
250 			if (res == 0 || (u_long)ap->end > (u_long)res->end)
251 				res = ap;
252 			continue;
253 		}
254 
255 		/* note key with the best future */
256 		if (res == 0 || (u_long)res->end < (u_long)ap->end)
257 			res = ap;
258 	}
259 	return res;
260 }
261 
262 
263 void
264 clr_ws_buf(struct ws_buf *wb,
265 	   struct auth *ap)
266 {
267 	struct netauth *na;
268 
269 	wb->lim = wb->base + NETS_LEN;
270 	wb->n = wb->base;
271 	memset(wb->n, 0, NETS_LEN*sizeof(*wb->n));
272 
273 	/* (start to) install authentication if appropriate
274 	 */
275 	if (ap == 0)
276 		return;
277 
278 	na = (struct netauth*)wb->n;
279 	if (ap->type == RIP_AUTH_PW) {
280 		na->a_family = RIP_AF_AUTH;
281 		na->a_type = RIP_AUTH_PW;
282 		memcpy(na->au.au_pw, ap->key, sizeof(na->au.au_pw));
283 		wb->n++;
284 
285 	} else if (ap->type ==  RIP_AUTH_MD5) {
286 		na->a_family = RIP_AF_AUTH;
287 		na->a_type = RIP_AUTH_MD5;
288 		na->au.a_md5.md5_keyid = ap->keyid;
289 		na->au.a_md5.md5_auth_len = RIP_AUTH_MD5_LEN;
290 		na->au.a_md5.md5_seqno = htonl(clk.tv_sec);
291 		wb->n++;
292 		wb->lim--;		/* make room for trailer */
293 	}
294 }
295 
296 
297 void
298 end_md5_auth(struct ws_buf *wb,
299 	     struct auth *ap)
300 {
301 	struct netauth *na, *na2;
302 	MD5_CTX md5_ctx;
303 	int len;
304 
305 
306 	na = (struct netauth*)wb->base;
307 	na2 = (struct netauth*)wb->n;
308 	len = (char *)na2-(char *)wb->buf;
309 	na2->a_family = RIP_AF_AUTH;
310 	na2->a_type = htons(1);
311 	na->au.a_md5.md5_pkt_len = htons(len);
312 	MD5Init(&md5_ctx);
313 	MD5Update(&md5_ctx, (u_char *)wb->buf, len);
314 	MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN);
315 	MD5Final(na2->au.au_pw, &md5_ctx);
316 	wb->n++;
317 }
318 
319 
320 /* Send the buffer
321  */
322 static void
323 supply_write(struct ws_buf *wb)
324 {
325 	/* Output multicast only if legal.
326 	 * If we would multicast and it would be illegal, then discard the
327 	 * packet.
328 	 */
329 	switch (wb->type) {
330 	case NO_OUT_MULTICAST:
331 		trace_pkt("skip multicast to %s because impossible",
332 			  naddr_ntoa(ws.to.sin_addr.s_addr));
333 		break;
334 	case NO_OUT_RIPV2:
335 		break;
336 	default:
337 		if (ws.a != 0 && ws.a->type == RIP_AUTH_MD5)
338 			end_md5_auth(wb,ws.a);
339 		if (output(wb->type, &ws.to, ws.ifp, wb->buf,
340 			   ((char *)wb->n - (char*)wb->buf)) < 0
341 		    && ws.ifp != 0)
342 			if_sick(ws.ifp);
343 		ws.npackets++;
344 		break;
345 	}
346 
347 	clr_ws_buf(wb,ws.a);
348 }
349 
350 
351 /* put an entry into the packet
352  */
353 static void
354 supply_out(struct ag_info *ag)
355 {
356 	int i;
357 	naddr mask, v1_mask, dst_h, ddst_h = 0;
358 	struct ws_buf *wb;
359 
360 
361 	/* Skip this route if doing a flash update and it and the routes
362 	 * it aggregates have not changed recently.
363 	 */
364 	if (ag->ag_seqno < update_seqno
365 	    && (ws.state & WS_ST_FLASH))
366 		return;
367 
368 	dst_h = ag->ag_dst_h;
369 	mask = ag->ag_mask;
370 	v1_mask = ripv1_mask_host(htonl(dst_h),
371 				  (ws.state & WS_ST_TO_ON_NET) ? ws.ifp : 0);
372 	i = 0;
373 
374 	/* If we are sending RIPv2 packets that cannot (or must not) be
375 	 * heard by RIPv1 listeners, do not worry about sub- or supernets.
376 	 * Subnets (from other networks) can only be sent via multicast.
377 	 * A pair of subnet routes might have been promoted so that they
378 	 * are legal to send by RIPv1.
379 	 * If RIPv1 is off, use the multicast buffer.
380 	 */
381 	if ((ws.state & WS_ST_RIP2_ALL)
382 	    || ((ag->ag_state & AGS_RIPV2) && v1_mask != mask)) {
383 		/* use the RIPv2-only buffer */
384 		wb = &v2buf;
385 
386 	} else {
387 		/* use the RIPv1-or-RIPv2 buffer */
388 		wb = &v12buf;
389 
390 		/* Convert supernet route into corresponding set of network
391 		 * routes for RIPv1, but leave non-contiguous netmasks
392 		 * to ag_check().
393 		 */
394 		if (v1_mask > mask
395 		    && mask + (mask & -mask) == 0) {
396 			ddst_h = v1_mask & -v1_mask;
397 			i = (v1_mask & ~mask)/ddst_h;
398 
399 			if (i > ws.gen_limit) {
400 				/* Punt if we would have to generate an
401 				 * unreasonable number of routes.
402 				 */
403 				if (TRACECONTENTS)
404 					trace_misc("sending %s-->%s as 1"
405 						   " instead of %d routes",
406 						   addrname(htonl(dst_h), mask,
407 							1),
408 						   naddr_ntoa(ws.to.sin_addr
409 							.s_addr),
410 						   i+1);
411 				i = 0;
412 
413 			} else {
414 				mask = v1_mask;
415 				ws.gen_limit -= i;
416 			}
417 		}
418 	}
419 
420 	do {
421 		wb->n->n_family = RIP_AF_INET;
422 		wb->n->n_dst = htonl(dst_h);
423 		/* If the route is from router-discovery or we are
424 		 * shutting down, admit only a bad metric.
425 		 */
426 		wb->n->n_metric = ((stopint || ag->ag_metric < 1)
427 				   ? HOPCNT_INFINITY
428 				   : ag->ag_metric);
429 		HTONL(wb->n->n_metric);
430 		/* Any non-zero bits in the supposedly unused RIPv1 fields
431 		 * cause the old `routed` to ignore the route.
432 		 * That means the mask and so forth cannot be sent
433 		 * in the hybrid RIPv1/RIPv2 mode.
434 		 */
435 		if (ws.state & WS_ST_RIP2_ALL) {
436 			if (ag->ag_nhop != 0
437 			    && ((ws.state & WS_ST_QUERY)
438 				|| (ag->ag_nhop != ws.ifp->int_addr
439 				    && on_net(ag->ag_nhop,
440 					      ws.ifp->int_net,
441 					      ws.ifp->int_mask))))
442 				wb->n->n_nhop = ag->ag_nhop;
443 			wb->n->n_mask = htonl(mask);
444 			wb->n->n_tag = ag->ag_tag;
445 		}
446 		dst_h += ddst_h;
447 
448 		if (++wb->n >= wb->lim)
449 			supply_write(wb);
450 	} while (i-- != 0);
451 }
452 
453 
454 /* supply one route from the table
455  */
456 /* ARGSUSED */
457 static int
458 walk_supply(struct radix_node *rn,
459 	    struct walkarg *argp UNUSED)
460 {
461 #define RT ((struct rt_entry *)rn)
462 	u_short ags;
463 	char metric, pref;
464 	naddr dst, nhop;
465 	struct rt_spare *rts;
466 	int i;
467 
468 
469 	/* Do not advertise external remote interfaces or passive interfaces.
470 	 */
471 	if ((RT->rt_state & RS_IF)
472 	    && RT->rt_ifp != 0
473 	    && (RT->rt_ifp->int_state & IS_PASSIVE)
474 	    && !(RT->rt_state & RS_MHOME))
475 		return 0;
476 
477 	/* If being quiet about our ability to forward, then
478 	 * do not say anything unless responding to a query,
479 	 * except about our main interface.
480 	 */
481 	if (!supplier && !(ws.state & WS_ST_QUERY)
482 	    && !(RT->rt_state & RS_MHOME))
483 		return 0;
484 
485 	dst = RT->rt_dst;
486 
487 	/* do not collide with the fake default route */
488 	if (dst == RIP_DEFAULT
489 	    && (ws.state & WS_ST_DEFAULT))
490 		return 0;
491 
492 	if (RT->rt_state & RS_NET_SYN) {
493 		if (RT->rt_state & RS_NET_INT) {
494 			/* Do not send manual synthetic network routes
495 			 * into the subnet.
496 			 */
497 			if (on_net(ws.to.sin_addr.s_addr,
498 				   ntohl(dst), RT->rt_mask))
499 				return 0;
500 
501 		} else {
502 			/* Do not send automatic synthetic network routes
503 			 * if they are not needed because no RIPv1 listeners
504 			 * can hear them.
505 			 */
506 			if (ws.state & WS_ST_RIP2_ALL)
507 				return 0;
508 
509 			/* Do not send automatic synthetic network routes to
510 			 * the real subnet.
511 			 */
512 			if (on_net(ws.to.sin_addr.s_addr,
513 				   ntohl(dst), RT->rt_mask))
514 				return 0;
515 		}
516 		nhop = 0;
517 
518 	} else {
519 		/* Advertise the next hop if this is not a route for one
520 		 * of our interfaces and the next hop is on the same
521 		 * network as the target.
522 		 * The final determination is made by supply_out().
523 		 */
524 		if (!(RT->rt_state & RS_IF)
525 		    && RT->rt_gate != myaddr
526 		    && RT->rt_gate != loopaddr)
527 			nhop = RT->rt_gate;
528 		else
529 			nhop = 0;
530 	}
531 
532 	metric = RT->rt_metric;
533 	ags = 0;
534 
535 	if (RT->rt_state & RS_MHOME) {
536 		/* retain host route of multi-homed servers */
537 		;
538 
539 	} else if (RT_ISHOST(RT)) {
540 		/* We should always suppress (into existing network routes)
541 		 * the host routes for the local end of our point-to-point
542 		 * links.
543 		 * If we are suppressing host routes in general, then do so.
544 		 * Avoid advertising host routes onto their own network,
545 		 * where they should be handled by proxy-ARP.
546 		 */
547 		if ((RT->rt_state & RS_LOCAL)
548 		    || ridhosts
549 		    || on_net(dst, ws.to_net, ws.to_mask))
550 			ags |= AGS_SUPPRESS;
551 
552 		/* Aggregate stray host routes into network routes if allowed.
553 		 * We cannot aggregate host routes into small network routes
554 		 * without confusing RIPv1 listeners into thinking the
555 		 * network routes are host routes.
556 		 */
557 		if ((ws.state & WS_ST_AG)
558 		    && !(ws.state & WS_ST_RIP2_ALL))
559 			ags |= AGS_AGGREGATE;
560 
561 	} else {
562 		/* Always suppress network routes into other, existing
563 		 * network routes
564 		 */
565 		ags |= AGS_SUPPRESS;
566 
567 		/* Generate supernets if allowed.
568 		 * If we can be heard by RIPv1 systems, we will
569 		 * later convert back to ordinary nets.
570 		 * This unifies dealing with received supernets.
571 		 */
572 		if ((ws.state & WS_ST_AG)
573 		    && ((RT->rt_state & RS_SUBNET)
574 			|| (ws.state & WS_ST_SUPER_AG)))
575 			ags |= AGS_AGGREGATE;
576 	}
577 
578 	/* Do not send RIPv1 advertisements of subnets to other
579 	 * networks. If possible, multicast them by RIPv2.
580 	 */
581 	if ((RT->rt_state & RS_SUBNET)
582 	    && !(ws.state & WS_ST_RIP2_ALL)
583 	    && !on_net(dst, ws.to_std_net, ws.to_std_mask))
584 		ags |= AGS_RIPV2 | AGS_AGGREGATE;
585 
586 
587 	/* Do not send a route back to where it came from, except in
588 	 * response to a query.  This is "split-horizon".  That means not
589 	 * advertising back to the same network	and so via the same interface.
590 	 *
591 	 * We want to suppress routes that might have been fragmented
592 	 * from this route by a RIPv1 router and sent back to us, and so we
593 	 * cannot forget this route here.  Let the split-horizon route
594 	 * suppress the fragmented routes and then itself be forgotten.
595 	 *
596 	 * Include the routes for both ends of point-to-point interfaces
597 	 * among those suppressed by split-horizon, since the other side
598 	 * should knows them as well as we do.
599 	 *
600 	 * Notice spare routes with the same metric that we are about to
601 	 * advertise, to split the horizon on redundant, inactive paths.
602 	 */
603 	if (ws.ifp != 0
604 	    && !(ws.state & WS_ST_QUERY)
605 	    && (ws.state & WS_ST_TO_ON_NET)
606 	    && (!(RT->rt_state & RS_IF)
607 		|| ws.ifp->int_if_flags & IFF_POINTOPOINT)) {
608 		for (rts = RT->rt_spares, i = NUM_SPARES; i != 0; i--, rts++) {
609 			if (rts->rts_metric > metric
610 			    || rts->rts_ifp != ws.ifp)
611 				continue;
612 
613 			/* If we do not mark the route with AGS_SPLIT_HZ here,
614 			 * it will be poisoned-reverse, or advertised back
615 			 * toward its source with an infinite metric.
616 			 * If we have recently advertised the route with a
617 			 * better metric than we now have, then we should
618 			 * poison-reverse the route before suppressing it for
619 			 * split-horizon.
620 			 *
621 			 * In almost all cases, if there is no spare for the
622 			 * route then it is either old and dead or a brand
623 			 * new route. If it is brand new, there is no need
624 			 * for poison-reverse. If it is old and dead, it
625 			 * is already poisoned.
626 			 */
627 			if (RT->rt_poison_time < now_expire
628 			    || RT->rt_poison_metric >= metric
629 			    || RT->rt_spares[1].rts_gate == 0) {
630 				ags |= AGS_SPLIT_HZ;
631 				ags &= ~AGS_SUPPRESS;
632 			}
633 			metric = HOPCNT_INFINITY;
634 			break;
635 		}
636 	}
637 
638 	/* Keep track of the best metric with which the
639 	 * route has been advertised recently.
640 	 */
641 	if (RT->rt_poison_metric >= metric
642 	    || RT->rt_poison_time < now_expire) {
643 		RT->rt_poison_time = now.tv_sec;
644 		RT->rt_poison_metric = metric;
645 	}
646 
647 	/* Adjust the outgoing metric by the cost of the link.
648 	 * Avoid aggregation when a route is counting to infinity.
649 	 */
650 	pref = RT->rt_poison_metric + ws.metric;
651 	metric += ws.metric;
652 
653 	/* Do not advertise stable routes that will be ignored,
654 	 * unless we are answering a query.
655 	 * If the route recently was advertised with a metric that
656 	 * would have been less than infinity through this interface,
657 	 * we need to continue to advertise it in order to poison it.
658 	 */
659 	if (metric >= HOPCNT_INFINITY) {
660 		if (!(ws.state & WS_ST_QUERY)
661 		    && (pref >= HOPCNT_INFINITY
662 			|| RT->rt_poison_time < now_garbage))
663 			return 0;
664 
665 		metric = HOPCNT_INFINITY;
666 	}
667 
668 	ag_check(dst, RT->rt_mask, 0, nhop, metric, pref,
669 		 RT->rt_seqno, RT->rt_tag, ags, supply_out);
670 	return 0;
671 #undef RT
672 }
673 
674 
675 /* Supply dst with the contents of the routing tables.
676  * If this won't fit in one packet, chop it up into several.
677  */
678 void
679 supply(struct sockaddr_in *dst,
680        struct interface *ifp,		/* output interface */
681        enum output_type type,
682        int flash,			/* 1=flash update */
683        int vers,			/* RIP version */
684        int passwd_ok)			/* OK to include cleartext password */
685 {
686 	struct rt_entry *rt;
687 	int def_metric;
688 
689 
690 	ws.state = 0;
691 	ws.gen_limit = 1024;
692 
693 	ws.to = *dst;
694 	ws.to_std_mask = std_mask(ws.to.sin_addr.s_addr);
695 	ws.to_std_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_std_mask;
696 
697 	if (ifp != 0) {
698 		ws.to_mask = ifp->int_mask;
699 		ws.to_net = ifp->int_net;
700 		if (on_net(ws.to.sin_addr.s_addr, ws.to_net, ws.to_mask))
701 			ws.state |= WS_ST_TO_ON_NET;
702 
703 	} else {
704 		ws.to_mask = ripv1_mask_net(ws.to.sin_addr.s_addr, 0);
705 		ws.to_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_mask;
706 		rt = rtfind(dst->sin_addr.s_addr);
707 		if (rt)
708 			ifp = rt->rt_ifp;
709 	}
710 
711 	ws.npackets = 0;
712 	if (flash)
713 		ws.state |= WS_ST_FLASH;
714 
715 	if ((ws.ifp = ifp) == 0) {
716 		ws.metric = 1;
717 	} else {
718 		/* Adjust the advertised metric by the outgoing interface
719 		 * metric.
720 		 */
721 		ws.metric = ifp->int_metric+1;
722 	}
723 
724 	ripv12_buf.rip.rip_vers = vers;
725 
726 	switch (type) {
727 	case OUT_MULTICAST:
728 		if (ifp->int_if_flags & IFF_MULTICAST)
729 			v2buf.type = OUT_MULTICAST;
730 		else
731 			v2buf.type = NO_OUT_MULTICAST;
732 		v12buf.type = OUT_BROADCAST;
733 		break;
734 
735 	case OUT_QUERY:
736 		ws.state |= WS_ST_QUERY;
737 		/* fall through */
738 	case OUT_BROADCAST:
739 	case OUT_UNICAST:
740 		v2buf.type = (vers == RIPv2) ? type : NO_OUT_RIPV2;
741 		v12buf.type = type;
742 		break;
743 
744 	case NO_OUT_MULTICAST:
745 	case NO_OUT_RIPV2:
746 		break;			/* no output */
747 	}
748 
749 	if (vers == RIPv2) {
750 		/* full RIPv2 only if cannot be heard by RIPv1 listeners */
751 		if (type != OUT_BROADCAST)
752 			ws.state |= WS_ST_RIP2_ALL;
753 		if ((ws.state & WS_ST_QUERY)
754 		    || !(ws.state & WS_ST_TO_ON_NET)) {
755 			ws.state |= (WS_ST_AG | WS_ST_SUPER_AG);
756 		} else if (ifp == 0 || !(ifp->int_state & IS_NO_AG)) {
757 			ws.state |= WS_ST_AG;
758 			if (type != OUT_BROADCAST
759 			    && (ifp == 0
760 				|| !(ifp->int_state & IS_NO_SUPER_AG)))
761 				ws.state |= WS_ST_SUPER_AG;
762 		}
763 	}
764 
765 	ws.a = (vers == RIPv2) ? find_auth(ifp) : 0;
766 	if (!passwd_ok && ws.a != 0 && ws.a->type == RIP_AUTH_PW)
767 		ws.a = 0;
768 	clr_ws_buf(&v12buf,ws.a);
769 	clr_ws_buf(&v2buf,ws.a);
770 
771 	/*  Fake a default route if asked and if there is not already
772 	 * a better, real default route.
773 	 */
774 	if (supplier && (def_metric = ifp->int_d_metric) != 0) {
775 		if (0 == (rt = rtget(RIP_DEFAULT, 0))
776 		    || rt->rt_metric+ws.metric >= def_metric) {
777 			ws.state |= WS_ST_DEFAULT;
778 			ag_check(0, 0, 0, 0, def_metric, def_metric,
779 				 0, 0, 0, supply_out);
780 		} else {
781 			def_metric = rt->rt_metric+ws.metric;
782 		}
783 
784 		/* If both RIPv2 and the poor-man's router discovery
785 		 * kludge are on, arrange to advertise an extra
786 		 * default route via RIPv1.
787 		 */
788 		if ((ws.state & WS_ST_RIP2_ALL)
789 		    && (ifp->int_state & IS_PM_RDISC)) {
790 			ripv12_buf.rip.rip_vers = RIPv1;
791 			v12buf.n->n_family = RIP_AF_INET;
792 			v12buf.n->n_dst = htonl(RIP_DEFAULT);
793 			v12buf.n->n_metric = htonl(def_metric);
794 			v12buf.n++;
795 		}
796 	}
797 
798 	(void)rn_walktree(rhead, walk_supply, 0);
799 	ag_flush(0,0,supply_out);
800 
801 	/* Flush the packet buffers, provided they are not empty and
802 	 * do not contain only the password.
803 	 */
804 	if (v12buf.n != v12buf.base
805 	    && (v12buf.n > v12buf.base+1
806 		|| v12buf.base->n_family != RIP_AF_AUTH))
807 		supply_write(&v12buf);
808 	if (v2buf.n != v2buf.base
809 	    && (v2buf.n > v2buf.base+1
810 		|| v2buf.base->n_family != RIP_AF_AUTH))
811 		supply_write(&v2buf);
812 
813 	/* If we sent nothing and this is an answer to a query, send
814 	 * an empty buffer.
815 	 */
816 	if (ws.npackets == 0
817 	    && (ws.state & WS_ST_QUERY))
818 		supply_write(&v12buf);
819 }
820 
821 
822 /* send all of the routing table or just do a flash update
823  */
824 void
825 rip_bcast(int flash)
826 {
827 #ifdef _HAVE_SIN_LEN
828 	static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
829 #else
830 	static struct sockaddr_in dst = {AF_INET};
831 #endif
832 	struct interface *ifp;
833 	enum output_type type;
834 	int vers;
835 	struct timeval rtime;
836 
837 
838 	need_flash = 0;
839 	intvl_random(&rtime, MIN_WAITTIME, MAX_WAITTIME);
840 	no_flash = rtime;
841 	timevaladd(&no_flash, &now);
842 
843 	if (rip_sock < 0)
844 		return;
845 
846 	trace_act("send %s and inhibit dynamic updates for %.3f sec",
847 		  flash ? "dynamic update" : "all routes",
848 		  rtime.tv_sec + ((float)rtime.tv_usec)/1000000.0);
849 
850 	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
851 		/* Skip interfaces not doing RIP.
852 		 * Do try broken interfaces to see if they have healed.
853 		 */
854 		if (IS_RIP_OUT_OFF(ifp->int_state))
855 			continue;
856 
857 		/* skip turned off interfaces */
858 		if (!iff_up(ifp->int_if_flags))
859 			continue;
860 
861 		vers = (ifp->int_state & IS_NO_RIPV1_OUT) ? RIPv2 : RIPv1;
862 
863 		if (ifp->int_if_flags & IFF_BROADCAST) {
864 			/* ordinary, hardware interface */
865 			dst.sin_addr.s_addr = ifp->int_brdaddr;
866 
867 			if (vers == RIPv2
868 			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
869 				type = OUT_MULTICAST;
870 			} else {
871 				type = OUT_BROADCAST;
872 			}
873 
874 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
875 			/* point-to-point hardware interface */
876 			dst.sin_addr.s_addr = ifp->int_dstaddr;
877 			type = OUT_UNICAST;
878 
879 		} else if (ifp->int_state & IS_REMOTE) {
880 			/* remote interface */
881 			dst.sin_addr.s_addr = ifp->int_addr;
882 			type = OUT_UNICAST;
883 
884 		} else {
885 			/* ATM, HIPPI, etc. */
886 			continue;
887 		}
888 
889 		supply(&dst, ifp, type, flash, vers, 1);
890 	}
891 
892 	update_seqno++;			/* all routes are up to date */
893 }
894 
895 
896 /* Ask for routes
897  * Do it only once to an interface, and not even after the interface
898  * was broken and recovered.
899  */
900 void
901 rip_query(void)
902 {
903 #ifdef _HAVE_SIN_LEN
904 	static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
905 #else
906 	static struct sockaddr_in dst = {AF_INET};
907 #endif
908 	struct interface *ifp;
909 	struct rip buf;
910 	enum output_type type;
911 
912 
913 	if (rip_sock < 0)
914 		return;
915 
916 	memset(&buf, 0, sizeof(buf));
917 
918 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
919 		/* Skip interfaces those already queried.
920 		 * Do not ask via interfaces through which we don't
921 		 * accept input.  Do not ask via interfaces that cannot
922 		 * send RIP packets.
923 		 * Do try broken interfaces to see if they have healed.
924 		 */
925 		if (IS_RIP_IN_OFF(ifp->int_state)
926 		    || ifp->int_query_time != NEVER)
927 			continue;
928 
929 		/* skip turned off interfaces */
930 		if (!iff_up(ifp->int_if_flags))
931 			continue;
932 
933 		buf.rip_vers = (ifp->int_state&IS_NO_RIPV1_OUT) ? RIPv2:RIPv1;
934 		buf.rip_cmd = RIPCMD_REQUEST;
935 		buf.rip_nets[0].n_family = RIP_AF_UNSPEC;
936 		buf.rip_nets[0].n_metric = htonl(HOPCNT_INFINITY);
937 
938 		/* Send a RIPv1 query only if allowed and if we will
939 		 * listen to RIPv1 routers.
940 		 */
941 		if ((ifp->int_state & IS_NO_RIPV1_OUT)
942 		    || (ifp->int_state & IS_NO_RIPV1_IN)) {
943 			buf.rip_vers = RIPv2;
944 		} else {
945 			buf.rip_vers = RIPv1;
946 		}
947 
948 		if (ifp->int_if_flags & IFF_BROADCAST) {
949 			/* ordinary, hardware interface */
950 			dst.sin_addr.s_addr = ifp->int_brdaddr;
951 
952 			/* Broadcast RIPv1 queries and RIPv2 queries
953 			 * when the hardware cannot multicast.
954 			 */
955 			if (buf.rip_vers == RIPv2
956 			    && (ifp->int_if_flags & IFF_MULTICAST)
957 			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
958 				type = OUT_MULTICAST;
959 			} else {
960 				type = OUT_BROADCAST;
961 			}
962 
963 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
964 			/* point-to-point hardware interface */
965 			dst.sin_addr.s_addr = ifp->int_dstaddr;
966 			type = OUT_UNICAST;
967 
968 		} else if (ifp->int_state & IS_REMOTE) {
969 			/* remote interface */
970 			dst.sin_addr.s_addr = ifp->int_addr;
971 			type = OUT_UNICAST;
972 
973 		} else {
974 			/* ATM, HIPPI, etc. */
975 			continue;
976 		}
977 
978 		ifp->int_query_time = now.tv_sec+SUPPLY_INTERVAL;
979 		if (output(type, &dst, ifp, &buf, sizeof(buf)) < 0)
980 			if_sick(ifp);
981 	}
982 }
983