xref: /freebsd/sbin/routed/output.c (revision a8445737e740901f5f2c8d24c12ef7fc8b00134e)
1 /*
2  * Copyright (c) 1983, 1988, 1993
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 acknowledgement:
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 
34 #ifndef lint
35 #if 0
36 static char sccsid[] = "@(#)output.c	8.1 (Berkeley) 6/5/93";
37 #endif
38 static const char rcsid[] =
39 	"$Id$";
40 #endif /* not lint */
41 
42 #include "defs.h"
43 
44 
45 int update_seqno;
46 
47 
48 /* walk the tree of routes with this for output
49  */
50 struct {
51 	struct sockaddr_in to;
52 	naddr	to_mask;
53 	naddr	to_net;
54 	naddr	to_std_mask;
55 	naddr	to_std_net;
56 	struct interface *ifp;		/* usually output interface */
57 	struct auth *a;
58 	char	metric;			/* adjust metrics by interface */
59 	int	npackets;
60 	int	gen_limit;
61 	u_int	state;
62 #define	    WS_ST_FLASH	    0x001	/* send only changed routes */
63 #define	    WS_ST_RIP2_ALL  0x002	/* send full featured RIPv2 */
64 #define	    WS_ST_AG	    0x004	/* ok to aggregate subnets */
65 #define	    WS_ST_SUPER_AG  0x008	/* ok to aggregate networks */
66 #define	    WS_ST_SUB_AG    0x010	/* aggregate subnets in odd case */
67 #define	    WS_ST_QUERY	    0x020	/* responding to a query */
68 #define	    WS_ST_TO_ON_NET 0x040	/* sending onto one of our nets */
69 #define	    WS_ST_DEFAULT   0x080	/* 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 union pkt_buf ripv12_buf;
75 
76 /* Another for only RIPv2 listeners */
77 struct ws_buf v2buf;
78 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 sin;
106 	int flags;
107 	char *msg;
108 	int res;
109 	naddr tgt_mcast;
110 	int soc;
111 	int serrno;
112 
113 	sin = *dst;
114 	if (sin.sin_port == 0)
115 		sin.sin_port = htons(RIP_PORT);
116 #ifdef _HAVE_SIN_LEN
117 	if (sin.sin_len == 0)
118 		sin.sin_len = sizeof(sin);
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) {
146 			msg = "Send pt-to-pt";
147 		} else if (ifp->int_state & IS_DUP) {
148 			trace_act("abort multicast output via %s"
149 				  " with duplicate address",
150 				  ifp->int_name);
151 			return 0;
152 		} else {
153 			msg = "Send mcast";
154 			if (rip_sock_mcast != ifp) {
155 #ifdef MCAST_PPP_BUG
156 				/* Do not specify the primary interface
157 				 * explicitly if we have the multicast
158 				 * point-to-point kernel bug, since the
159 				 * kernel will do the wrong thing if the
160 				 * local address of a point-to-point link
161 				 * is the same as the address of an ordinary
162 				 * interface.
163 				 */
164 				if (ifp->int_addr == myaddr) {
165 					tgt_mcast = 0;
166 				} else
167 #endif
168 				tgt_mcast = ifp->int_addr;
169 				if (0 > setsockopt(rip_sock,
170 						   IPPROTO_IP, IP_MULTICAST_IF,
171 						   &tgt_mcast,
172 						   sizeof(tgt_mcast))) {
173 					serrno = errno;
174 					LOGERR("setsockopt(rip_sock,"
175 					       "IP_MULTICAST_IF)");
176 					errno = serrno;
177 					ifp = 0;
178 					return -1;
179 				}
180 				rip_sock_mcast = ifp;
181 			}
182 			sin.sin_addr.s_addr = htonl(INADDR_RIP_GROUP);
183 		}
184 		break;
185 
186 	case NO_OUT_MULTICAST:
187 	case NO_OUT_RIPV2:
188 	default:
189 #ifdef DEBUG
190 		abort();
191 #endif
192 		return -1;
193 	}
194 
195 	trace_rip(msg, "to", &sin, ifp, buf, size);
196 
197 	res = sendto(soc, buf, size, flags,
198 		     (struct sockaddr *)&sin, sizeof(sin));
199 	if (res < 0
200 	    && (ifp == 0 || !(ifp->int_state & IS_BROKE))) {
201 		serrno = errno;
202 		msglog("%s sendto(%s%s%s.%d): %s", msg,
203 		       ifp != 0 ? ifp->int_name : "",
204 		       ifp != 0 ? ", " : "",
205 		       inet_ntoa(sin.sin_addr),
206 		       ntohs(sin.sin_port),
207 		       strerror(errno));
208 		errno = serrno;
209 	}
210 
211 	return res;
212 }
213 
214 
215 /* Find the first key for a packet to send.
216  * Try for a key that is eligible and has not expired, but settle for
217  * the last key if they have all expired.
218  * If no key is ready yet, give up.
219  */
220 struct auth *
221 find_auth(struct interface *ifp)
222 {
223 	struct auth *ap, *res;
224 	int i;
225 
226 
227 	if (ifp == 0)
228 		return 0;
229 
230 	res = 0;
231 	ap = ifp->int_auth;
232 	for (i = 0; i < MAX_AUTH_KEYS; i++, ap++) {
233 		/* stop looking after the last key */
234 		if (ap->type == RIP_AUTH_NONE)
235 			break;
236 
237 		/* ignore keys that are not ready yet */
238 		if ((u_long)ap->start > (u_long)clk.tv_sec)
239 			continue;
240 
241 		if ((u_long)ap->end < (u_long)clk.tv_sec) {
242 			/* note best expired password as a fall-back */
243 			if (res == 0 || (u_long)ap->end > (u_long)res->end)
244 				res = ap;
245 			continue;
246 		}
247 
248 		/* note key with the best future */
249 		if (res == 0 || (u_long)res->end < (u_long)ap->end)
250 			res = ap;
251 	}
252 	return res;
253 }
254 
255 
256 void
257 clr_ws_buf(struct ws_buf *wb,
258 	   struct auth *ap)
259 {
260 	struct netauth *na;
261 
262 	wb->lim = wb->base + NETS_LEN;
263 	wb->n = wb->base;
264 	bzero(wb->n, NETS_LEN*sizeof(*wb->n));
265 
266 	/* install authentication if appropriate
267 	 */
268 	if (ap == 0)
269 		return;
270 	na = (struct netauth*)wb->n;
271 	if (ap->type == RIP_AUTH_PW) {
272 		na->a_family = RIP_AF_AUTH;
273 		na->a_type = RIP_AUTH_PW;
274 		bcopy(ap->key, na->au.au_pw, sizeof(na->au.au_pw));
275 		wb->n++;
276 
277 	} else if (ap->type ==  RIP_AUTH_MD5) {
278 		na->a_family = RIP_AF_AUTH;
279 		na->a_type = RIP_AUTH_MD5;
280 		na->au.a_md5.md5_keyid = ap->keyid;
281 		na->au.a_md5.md5_auth_len = RIP_AUTH_PW_LEN;
282 		na->au.a_md5.md5_seqno = clk.tv_sec;
283 		wb->n++;
284 		wb->lim--;		/* make room for trailer */
285 	}
286 }
287 
288 
289 void
290 end_md5_auth(struct ws_buf *wb,
291 	     struct auth *ap)
292 {
293 	struct netauth *na, *na2;
294 	MD5_CTX md5_ctx;
295 
296 
297 	na = (struct netauth*)wb->base;
298 	na2 = (struct netauth*)wb->n;
299 	na2->a_family = RIP_AF_AUTH;
300 	na2->a_type = 1;
301 	bcopy(ap->key, na2->au.au_pw, sizeof(na2->au.au_pw));
302 	na->au.a_md5.md5_pkt_len = (char *)na2-(char *)(na+1);
303 	MD5Init(&md5_ctx);
304 	MD5Update(&md5_ctx, (u_char *)na,
305 		  (char *)(na2+1) - (char *)na);
306 	MD5Final(na2->au.au_pw, &md5_ctx);
307 	wb->n++;
308 }
309 
310 
311 /* Send the buffer
312  */
313 static void
314 supply_write(struct ws_buf *wb)
315 {
316 	/* Output multicast only if legal.
317 	 * If we would multicast and it would be illegal, then discard the
318 	 * packet.
319 	 */
320 	switch (wb->type) {
321 	case NO_OUT_MULTICAST:
322 		trace_pkt("skip multicast to %s because impossible",
323 			  naddr_ntoa(ws.to.sin_addr.s_addr));
324 		break;
325 	case NO_OUT_RIPV2:
326 		break;
327 	default:
328 		if (ws.a != 0 && ws.a->type == RIP_AUTH_MD5)
329 			end_md5_auth(wb,ws.a);
330 		if (output(wb->type, &ws.to, ws.ifp, wb->buf,
331 			   ((char *)wb->n - (char*)wb->buf)) < 0
332 		    && ws.ifp != 0)
333 			if_sick(ws.ifp);
334 		ws.npackets++;
335 		break;
336 	}
337 
338 	clr_ws_buf(wb,ws.a);
339 }
340 
341 
342 /* put an entry into the packet
343  */
344 static void
345 supply_out(struct ag_info *ag)
346 {
347 	int i;
348 	naddr mask, v1_mask, dst_h, ddst_h = 0;
349 	struct ws_buf *wb;
350 
351 
352 	/* Skip this route if doing a flash update and it and the routes
353 	 * it aggregates have not changed recently.
354 	 */
355 	if (ag->ag_seqno < update_seqno
356 	    && (ws.state & WS_ST_FLASH))
357 		return;
358 
359 	/* Skip this route if required by split-horizon.
360 	 */
361 	if (ag->ag_state & AGS_SPLIT_HZ)
362 		return;
363 
364 	dst_h = ag->ag_dst_h;
365 	mask = ag->ag_mask;
366 	v1_mask = ripv1_mask_host(htonl(dst_h),
367 				  (ws.state & WS_ST_TO_ON_NET) ? ws.ifp : 0);
368 	i = 0;
369 
370 	/* If we are sending RIPv2 packets that cannot (or must not) be
371 	 * heard by RIPv1 listeners, do not worry about sub- or supernets.
372 	 * Subnets (from other networks) can only be sent via multicast.
373 	 * A pair of subnet routes might have been promoted so that they
374 	 * are legal to send by RIPv1.
375 	 * If RIPv1 is off, use the multicast buffer.
376 	 */
377 	if ((ws.state & WS_ST_RIP2_ALL)
378 	    || ((ag->ag_state & AGS_RIPV2) && v1_mask != mask)) {
379 		/* use the RIPv2-only buffer */
380 		wb = &v2buf;
381 
382 	} else {
383 		/* use the RIPv1-or-RIPv2 buffer */
384 		wb = &v12buf;
385 
386 		/* Convert supernet route into corresponding set of network
387 		 * routes for RIPv1, but leave non-contiguous netmasks
388 		 * to ag_check().
389 		 */
390 		if (v1_mask > mask
391 		    && mask + (mask & -mask) == 0) {
392 			ddst_h = v1_mask & -v1_mask;
393 			i = (v1_mask & ~mask)/ddst_h;
394 
395 			if (i > ws.gen_limit) {
396 				/* Punt if we would have to generate an
397 				 * unreasonable number of routes.
398 				 */
399 #ifdef DEBUG
400 				msglog("sending %s to %s as 1 instead"
401 				       " of %d routes",
402 				       addrname(htonl(dst_h),mask,1),
403 				       naddr_ntoa(ws.to.sin_addr.s_addr),
404 				       i+1);
405 #endif
406 				i = 0;
407 
408 			} else {
409 				mask = v1_mask;
410 				ws.gen_limit -= i;
411 			}
412 		}
413 	}
414 
415 	do {
416 		wb->n->n_family = RIP_AF_INET;
417 		wb->n->n_dst = htonl(dst_h);
418 		/* If the route is from router-discovery or we are
419 		 * shutting down, admit only a bad metric.
420 		 */
421 		wb->n->n_metric = ((stopint || ag->ag_metric < 1)
422 				   ? HOPCNT_INFINITY
423 				   : ag->ag_metric);
424 		HTONL(wb->n->n_metric);
425 		/* Any non-zero bits in the supposedly unused RIPv1 fields
426 		 * cause the old `routed` to ignore the route.
427 		 * That means the mask and so forth cannot be sent
428 		 * in the hybrid RIPv1/RIPv2 mode.
429 		 */
430 		if (ws.state & WS_ST_RIP2_ALL) {
431 			if (ag->ag_nhop != 0
432 			    && ((ws.state & WS_ST_QUERY)
433 				|| (ag->ag_nhop != ws.ifp->int_addr
434 				    && on_net(ag->ag_nhop,
435 					      ws.ifp->int_net,
436 					      ws.ifp->int_mask))))
437 				wb->n->n_nhop = ag->ag_nhop;
438 			wb->n->n_mask = htonl(mask);
439 			wb->n->n_tag = ag->ag_tag;
440 		}
441 		dst_h += ddst_h;
442 
443 		if (++wb->n >= wb->lim)
444 			supply_write(wb);
445 	} while (i-- != 0);
446 }
447 
448 
449 /* supply one route from the table
450  */
451 /* ARGSUSED */
452 static int
453 walk_supply(struct radix_node *rn,
454 	    struct walkarg *w)
455 {
456 #define RT ((struct rt_entry *)rn)
457 	u_short ags;
458 	char metric, pref;
459 	naddr dst, nhop;
460 
461 
462 	/* Do not advertise external remote interfaces or passive interfaces.
463 	 */
464 	if ((RT->rt_state & RS_IF)
465 	    && RT->rt_ifp != 0
466 	    && (RT->rt_ifp->int_if_flags & IS_PASSIVE)
467 	    && !(RT->rt_state & RS_MHOME))
468 		return 0;
469 
470 	/* If being quiet about our ability to forward, then
471 	 * do not say anything unless responding to a query,
472 	 * except about our main interface.
473 	 */
474 	if (!supplier && !(ws.state & WS_ST_QUERY)
475 	    && !(RT->rt_state & RS_MHOME))
476 		return 0;
477 
478 	dst = RT->rt_dst;
479 
480 	/* do not collide with the fake default route */
481 	if (dst == RIP_DEFAULT
482 	    && (ws.state & WS_ST_DEFAULT))
483 		return 0;
484 
485 	if (RT->rt_state & RS_NET_SYN) {
486 		if (RT->rt_state & RS_NET_INT) {
487 			/* Do not send manual synthetic network routes
488 			 * into the subnet.
489 			 */
490 			if (on_net(ws.to.sin_addr.s_addr,
491 				   ntohl(dst), RT->rt_mask))
492 				return 0;
493 
494 		} else {
495 			/* Do not send automatic synthetic network routes
496 			 * if they are not needed because no RIPv1 listeners
497 			 * can hear them.
498 			 */
499 			if (ws.state & WS_ST_RIP2_ALL)
500 				return 0;
501 
502 			/* Do not send automatic synthetic network routes to
503 			 * the real subnet.
504 			 */
505 			if (on_net(ws.to.sin_addr.s_addr,
506 				   ntohl(dst), RT->rt_mask))
507 				return 0;
508 		}
509 		nhop = 0;
510 
511 	} else {
512 		/* Advertise the next hop if this is not a route for one
513 		 * of our interfaces and the next hop is on the same
514 		 * network as the target.
515 		 */
516 		if (!(RT->rt_state & RS_IF)
517 		    && RT->rt_gate != myaddr
518 		    && RT->rt_gate != loopaddr)
519 			nhop = RT->rt_gate;
520 		else
521 			nhop = 0;
522 	}
523 
524 	metric = RT->rt_metric;
525 	ags = 0;
526 
527 	if (RT->rt_state & RS_MHOME) {
528 		/* retain host route of multi-homed servers */
529 		;
530 
531 	} else if (RT_ISHOST(RT)) {
532 		/* We should always aggregate the host routes
533 		 * for the local end of our point-to-point links.
534 		 * If we are suppressing host routes in general, then do so.
535 		 * Avoid advertising host routes onto their own network,
536 		 * where they should be handled by proxy-ARP.
537 		 */
538 		if ((RT->rt_state & RS_LOCAL)
539 		    || ridhosts
540 		    || (ws.state & WS_ST_SUPER_AG)
541 		    || on_net(dst, ws.to_net, ws.to_mask))
542 			ags |= AGS_SUPPRESS;
543 
544 		if (ws.state & WS_ST_SUPER_AG)
545 			ags |= AGS_PROMOTE;
546 
547 	} else if (ws.state & WS_ST_AG) {
548 		/* Aggregate network routes, if we are allowed.
549 		 */
550 		ags |= AGS_SUPPRESS;
551 
552 		/* Generate supernets if allowed.
553 		 * If we can be heard by RIPv1 systems, we will
554 		 * later convert back to ordinary nets.
555 		 * This unifies dealing with received supernets.
556 		 */
557 		if ((RT->rt_state & RS_SUBNET)
558 		    || (ws.state & WS_ST_SUPER_AG))
559 			ags |= AGS_PROMOTE;
560 
561 	}
562 
563 	/* Do not send RIPv1 advertisements of subnets to other
564 	 * networks. If possible, multicast them by RIPv2.
565 	 */
566 	if ((RT->rt_state & RS_SUBNET)
567 	    && !(ws.state & WS_ST_RIP2_ALL)
568 	    && !on_net(dst, ws.to_std_net, ws.to_std_mask)) {
569 		ags |= AGS_RIPV2 | AGS_PROMOTE;
570 		if (ws.state & WS_ST_SUB_AG)
571 			ags |= AGS_SUPPRESS;
572 	}
573 
574 	/* Do not send a route back to where it came from, except in
575 	 * response to a query.  This is "split-horizon".  That means not
576 	 * advertising back to the same network	and so via the same interface.
577 	 *
578 	 * We want to suppress routes that might have been fragmented
579 	 * from this route by a RIPv1 router and sent back to us, and so we
580 	 * cannot forget this route here.  Let the split-horizon route
581 	 * aggregate (suppress) the fragmented routes and then itself be
582 	 * forgotten.
583 	 *
584 	 * Include the routes for both ends of point-to-point interfaces
585 	 * among those suppressed by split-horizon, since the other side
586 	 * should knows them as well as we do.
587 	 */
588 	if (RT->rt_ifp == ws.ifp && ws.ifp != 0
589 	    && !(ws.state & WS_ST_QUERY)
590 	    && (ws.state & WS_ST_TO_ON_NET)
591 	    && (!(RT->rt_state & RS_IF)
592 		|| ws.ifp->int_if_flags & IFF_POINTOPOINT)) {
593 		/* If we do not mark the route with AGS_SPLIT_HZ here,
594 		 * it will be poisoned-reverse, or advertised back toward
595 		 * its source with an infinite metric.  If we have recently
596 		 * advertised the route with a better metric than we now
597 		 * have, then we should poison-reverse the route before
598 		 * suppressing it for split-horizon.
599 		 *
600 		 * In almost all cases, if there is no spare for the route
601 		 * then it is either old and dead or a brand new route.
602 		 * If it is brand new, there is no need for poison-reverse.
603 		 * If it is old and dead, it is already poisoned.
604 		 */
605 		if (RT->rt_poison_time < now_expire
606 		    || RT->rt_poison_metric >= metric
607 		    || RT->rt_spares[1].rts_gate == 0) {
608 			ags |= AGS_SPLIT_HZ;
609 			ags &= ~(AGS_PROMOTE | AGS_SUPPRESS);
610 		}
611 		metric = HOPCNT_INFINITY;
612 	}
613 
614 	/* Adjust the outgoing metric by the cost of the link.
615 	 */
616 	pref = metric + ws.metric;
617 	if (pref < HOPCNT_INFINITY) {
618 		/* Keep track of the best metric with which the
619 		 * route has been advertised recently.
620 		 */
621 		if (RT->rt_poison_metric >= metric
622 		    || RT->rt_poison_time < now_expire) {
623 			RT->rt_poison_time = now.tv_sec;
624 			RT->rt_poison_metric = metric;
625 		}
626 		metric = pref;
627 
628 	} else {
629 		/* Do not advertise stable routes that will be ignored,
630 		 * unless we are answering a query.
631 		 * If the route recently was advertised with a metric that
632 		 * would have been less than infinity through this interface,
633 		 * we need to continue to advertise it in order to poison it.
634 		 */
635 		pref = RT->rt_poison_metric + ws.metric;
636 		if (!(ws.state & WS_ST_QUERY)
637 		    && (pref >= HOPCNT_INFINITY
638 			|| RT->rt_poison_time < now_garbage))
639 			return 0;
640 
641 		metric = HOPCNT_INFINITY;
642 	}
643 
644 	ag_check(dst, RT->rt_mask, 0, nhop, metric, pref,
645 		 RT->rt_seqno, RT->rt_tag, ags, supply_out);
646 	return 0;
647 #undef RT
648 }
649 
650 
651 /* Supply dst with the contents of the routing tables.
652  * If this won't fit in one packet, chop it up into several.
653  */
654 void
655 supply(struct sockaddr_in *dst,
656        struct interface *ifp,		/* output interface */
657        enum output_type type,
658        int flash,			/* 1=flash update */
659        int vers,			/* RIP version */
660        int passwd_ok)			/* OK to include cleartext password */
661 {
662 	struct rt_entry *rt;
663 	int def_metric;
664 
665 
666 	ws.state = 0;
667 	ws.gen_limit = 1024;
668 
669 	ws.to = *dst;
670 	ws.to_std_mask = std_mask(ws.to.sin_addr.s_addr);
671 	ws.to_std_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_std_mask;
672 
673 	if (ifp != 0) {
674 		ws.to_mask = ifp->int_mask;
675 		ws.to_net = ifp->int_net;
676 		if (on_net(ws.to.sin_addr.s_addr, ws.to_net, ws.to_mask))
677 			ws.state |= WS_ST_TO_ON_NET;
678 
679 	} else {
680 		ws.to_mask = ripv1_mask_net(ws.to.sin_addr.s_addr, 0);
681 		ws.to_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_mask;
682 		rt = rtfind(dst->sin_addr.s_addr);
683 		if (rt)
684 			ifp = rt->rt_ifp;
685 	}
686 
687 	ws.npackets = 0;
688 	if (flash)
689 		ws.state |= WS_ST_FLASH;
690 	if (type == OUT_QUERY)
691 		ws.state |= WS_ST_QUERY;
692 
693 	if ((ws.ifp = ifp) == 0) {
694 		ws.metric = 1;
695 	} else {
696 		/* Adjust the advertised metric by the outgoing interface
697 		 * metric.
698 		 */
699 		ws.metric = ifp->int_metric+1;
700 	}
701 
702 	ripv12_buf.rip.rip_vers = vers;
703 
704 	switch (type) {
705 	case OUT_BROADCAST:
706 		v2buf.type = ((ifp != 0 && (ifp->int_if_flags & IFF_MULTICAST))
707 			      ? OUT_MULTICAST
708 			      : NO_OUT_MULTICAST);
709 		v12buf.type = OUT_BROADCAST;
710 		break;
711 	case OUT_MULTICAST:
712 		v2buf.type = ((ifp != 0 && (ifp->int_if_flags & IFF_MULTICAST))
713 			      ? OUT_MULTICAST
714 			      : NO_OUT_MULTICAST);
715 		v12buf.type = OUT_BROADCAST;
716 		break;
717 	case OUT_UNICAST:
718 	case OUT_QUERY:
719 		v2buf.type = (vers == RIPv2) ? type : NO_OUT_RIPV2;
720 		v12buf.type = type;
721 		break;
722 	default:
723 		v2buf.type = type;
724 		v12buf.type = type;
725 		break;
726 	}
727 
728 	if (vers == RIPv2) {
729 		/* full RIPv2 only if cannot be heard by RIPv1 listeners */
730 		if (type != OUT_BROADCAST)
731 			ws.state |= WS_ST_RIP2_ALL;
732 		if (!(ws.state & WS_ST_TO_ON_NET)) {
733 			ws.state |= (WS_ST_AG | WS_ST_SUPER_AG);
734 		} else if (ifp == 0 || !(ifp->int_state & IS_NO_AG)) {
735 			ws.state |= WS_ST_AG;
736 			if (type != OUT_BROADCAST
737 			    && (ifp == 0 || !(ifp->int_state&IS_NO_SUPER_AG)))
738 				ws.state |= WS_ST_SUPER_AG;
739 		}
740 
741 	} else if (ifp == 0 || !(ifp->int_state & IS_NO_AG)) {
742 		ws.state |= WS_ST_SUB_AG;
743 	}
744 
745 	ws.a = (vers == RIPv2) ? find_auth(ifp) : 0;
746 	if (!passwd_ok && ws.a != 0 && ws.a->type == RIP_AUTH_PW)
747 		ws.a = 0;
748 	clr_ws_buf(&v12buf,ws.a);
749 	clr_ws_buf(&v2buf,ws.a);
750 
751 	/*  Fake a default route if asked and if there is not already
752 	 * a better, real default route.
753 	 */
754 	if (supplier && (def_metric = ifp->int_d_metric) != 0) {
755 		if (0 == (rt = rtget(RIP_DEFAULT, 0))
756 		    || rt->rt_metric+ws.metric >= def_metric) {
757 			ws.state |= WS_ST_DEFAULT;
758 			ag_check(0, 0, 0, 0, def_metric, def_metric,
759 				 0, 0, 0, supply_out);
760 		} else {
761 			def_metric = rt->rt_metric+ws.metric;
762 		}
763 
764 		/* If both RIPv2 and the poor-man's router discovery
765 		 * kludge are on, arrange to advertise an extra
766 		 * default route via RIPv1.
767 		 */
768 		if ((ws.state & WS_ST_RIP2_ALL)
769 		    && (ifp->int_state & IS_PM_RDISC)) {
770 			ripv12_buf.rip.rip_vers = RIPv1;
771 			v12buf.n->n_family = RIP_AF_INET;
772 			v12buf.n->n_dst = htonl(RIP_DEFAULT);
773 			v12buf.n->n_metric = htonl(def_metric);
774 			v12buf.n++;
775 		}
776 	}
777 
778 	(void)rn_walktree(rhead, walk_supply, 0);
779 	ag_flush(0,0,supply_out);
780 
781 	/* Flush the packet buffers, provided they are not empty and
782 	 * do not contain only the password.
783 	 */
784 	if (v12buf.n != v12buf.base
785 	    && (v12buf.n > v12buf.base+1
786 		|| v12buf.base->n_family != RIP_AF_AUTH))
787 		supply_write(&v12buf);
788 	if (v2buf.n != v2buf.base
789 	    && (v2buf.n > v2buf.base+1
790 		|| v2buf.base->n_family != RIP_AF_AUTH))
791 		supply_write(&v2buf);
792 
793 	/* If we sent nothing and this is an answer to a query, send
794 	 * an empty buffer.
795 	 */
796 	if (ws.npackets == 0
797 	    && (ws.state & WS_ST_QUERY))
798 		supply_write(&v12buf);
799 }
800 
801 
802 /* send all of the routing table or just do a flash update
803  */
804 void
805 rip_bcast(int flash)
806 {
807 #ifdef _HAVE_SIN_LEN
808 	static struct sockaddr_in dst = {sizeof(dst), AF_INET};
809 #else
810 	static struct sockaddr_in dst = {AF_INET};
811 #endif
812 	struct interface *ifp;
813 	enum output_type type;
814 	int vers;
815 	struct timeval rtime;
816 
817 
818 	need_flash = 0;
819 	intvl_random(&rtime, MIN_WAITTIME, MAX_WAITTIME);
820 	no_flash = rtime;
821 	timevaladd(&no_flash, &now);
822 
823 	if (rip_sock < 0)
824 		return;
825 
826 	trace_act("send %s and inhibit dynamic updates for %.3f sec",
827 		  flash ? "dynamic update" : "all routes",
828 		  rtime.tv_sec + ((float)rtime.tv_usec)/1000000.0);
829 
830 	for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
831 		/* Skip interfaces not doing RIP.
832 		 * Do try broken interfaces to see if they have healed.
833 		 */
834 		if (IS_RIP_OUT_OFF(ifp->int_state))
835 			continue;
836 
837 		/* skip turned off interfaces */
838 		if (!iff_alive(ifp->int_if_flags))
839 			continue;
840 
841 		vers = (ifp->int_state & IS_NO_RIPV1_OUT) ? RIPv2 : RIPv1;
842 
843 		if (ifp->int_if_flags & IFF_BROADCAST) {
844 			/* ordinary, hardware interface */
845 			dst.sin_addr.s_addr = ifp->int_brdaddr;
846 
847 			/* If RIPv1 is not turned off, then broadcast so
848 			 * that RIPv1 listeners can hear.
849 			 */
850 			if (vers == RIPv2
851 			    && (ifp->int_state & IS_NO_RIPV1_OUT)) {
852 				type = OUT_MULTICAST;
853 			} else {
854 				type = OUT_BROADCAST;
855 			}
856 
857 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
858 			/* point-to-point hardware interface */
859 			dst.sin_addr.s_addr = ifp->int_dstaddr;
860 			type = OUT_UNICAST;
861 
862 		} else if (ifp->int_state & IS_REMOTE) {
863 			/* remote interface */
864 			dst.sin_addr.s_addr = ifp->int_addr;
865 			type = OUT_UNICAST;
866 
867 		} else {
868 			/* ATM, HIPPI, etc. */
869 			continue;
870 		}
871 
872 		supply(&dst, ifp, type, flash, vers, 1);
873 	}
874 
875 	update_seqno++;			/* all routes are up to date */
876 }
877 
878 
879 /* Ask for routes
880  * Do it only once to an interface, and not even after the interface
881  * was broken and recovered.
882  */
883 void
884 rip_query(void)
885 {
886 #ifdef _HAVE_SIN_LEN
887 	static struct sockaddr_in dst = {sizeof(dst), AF_INET};
888 #else
889 	static struct sockaddr_in dst = {AF_INET};
890 #endif
891 	struct interface *ifp;
892 	struct rip buf;
893 	enum output_type type;
894 
895 
896 	if (rip_sock < 0)
897 		return;
898 
899 	bzero(&buf, sizeof(buf));
900 
901 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
902 		/* Skip interfaces those already queried.
903 		 * Do not ask via interfaces through which we don't
904 		 * accept input.  Do not ask via interfaces that cannot
905 		 * send RIP packets.
906 		 * Do try broken interfaces to see if they have healed.
907 		 */
908 		if (IS_RIP_IN_OFF(ifp->int_state)
909 		    || ifp->int_query_time != NEVER)
910 			continue;
911 
912 		/* skip turned off interfaces */
913 		if (!iff_alive(ifp->int_if_flags))
914 			continue;
915 
916 		buf.rip_vers = (ifp->int_state&IS_NO_RIPV1_OUT) ? RIPv2:RIPv1;
917 		buf.rip_cmd = RIPCMD_REQUEST;
918 		buf.rip_nets[0].n_family = RIP_AF_UNSPEC;
919 		buf.rip_nets[0].n_metric = htonl(HOPCNT_INFINITY);
920 
921 		if (ifp->int_if_flags & IFF_BROADCAST) {
922 			/* ordinary, hardware interface */
923 			dst.sin_addr.s_addr = ifp->int_brdaddr;
924 			/* if RIPv1 is not turned off, then broadcast so
925 			 * that RIPv1 listeners can hear.
926 			 */
927 			if (buf.rip_vers == RIPv2
928 			    && (ifp->int_state & IS_NO_RIPV1_OUT)) {
929 				type = OUT_MULTICAST;
930 			} else {
931 				type = OUT_BROADCAST;
932 			}
933 
934 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
935 			/* point-to-point hardware interface */
936 			dst.sin_addr.s_addr = ifp->int_dstaddr;
937 			type = OUT_UNICAST;
938 
939 		} else if (ifp->int_state & IS_REMOTE) {
940 			/* remote interface */
941 			dst.sin_addr.s_addr = ifp->int_addr;
942 			type = OUT_UNICAST;
943 
944 		} else {
945 			/* ATM, HIPPI, etc. */
946 			continue;
947 		}
948 
949 		ifp->int_query_time = now.tv_sec+SUPPLY_INTERVAL;
950 		if (output(type, &dst, ifp, &buf, sizeof(buf)) < 0)
951 			if_sick(ifp);
952 	}
953 }
954