xref: /openbsd/usr.sbin/ripd/rde.c (revision cecf84d4) 
1 /*	$OpenBSD: rde.c,v 1.18 2015/01/16 06:40:20 deraadt Exp $ */
2 
3 /*
4  * Copyright (c) 2006 Michele Marchetto <mydecay@openbeer.it>
5  * Copyright (c) 2004, 2005 Claudio Jeker <claudio@openbsd.org>
6  * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
7  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
8  *
9  * Permission to use, copy, modify, and distribute this software for any
10  * purpose with or without fee is hereby granted, provided that the above
11  * copyright notice and this permission notice appear in all copies.
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
15  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
19  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20  */
21 
22 #include <sys/socket.h>
23 #include <sys/queue.h>
24 #include <netinet/in.h>
25 #include <arpa/inet.h>
26 #include <err.h>
27 #include <errno.h>
28 #include <stdlib.h>
29 #include <signal.h>
30 #include <string.h>
31 #include <pwd.h>
32 #include <unistd.h>
33 #include <event.h>
34 
35 #include "ripd.h"
36 #include "rip.h"
37 #include "ripe.h"
38 #include "log.h"
39 #include "rde.h"
40 
41 #define	MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
42 
43 struct ripd_conf	*rdeconf = NULL;
44 struct imsgev		*iev_ripe;
45 struct imsgev		*iev_main;
46 
47 void	rde_sig_handler(int, short, void *);
48 void	rde_shutdown(void);
49 void	rde_dispatch_imsg(int, short, void *);
50 void	rde_dispatch_parent(int, short, void *);
51 int	rde_imsg_compose_ripe(int, u_int32_t, pid_t, void *, u_int16_t);
52 int	rde_check_route(struct rip_route *);
53 void	triggered_update(struct rt_node *);
54 
55 /* ARGSUSED */
56 void
57 rde_sig_handler(int sig, short event, void *arg)
58 {
59 	/*
60 	 * signal handler rules don't apply, libevent decouples for us
61 	 */
62 
63 	switch (sig) {
64 	case SIGINT:
65 	case SIGTERM:
66 		rde_shutdown();
67 		/* NOTREACHED */
68 	default:
69 		fatalx("unexpected signal");
70 	}
71 }
72 
73 /* route decision engine */
74 pid_t
75 rde(struct ripd_conf *xconf, int pipe_parent2rde[2], int pipe_ripe2rde[2],
76     int pipe_parent2ripe[2])
77 {
78 	struct event		 ev_sigint, ev_sigterm;
79 	struct passwd		*pw;
80 	struct redistribute	*r;
81 	pid_t			 pid;
82 
83 	switch (pid = fork()) {
84 	case -1:
85 		fatal("cannot fork");
86 		/* NOTREACHED */
87 	case 0:
88 		break;
89 	default:
90 		return (pid);
91 	}
92 
93 	rdeconf = xconf;
94 
95 	if ((pw = getpwnam(RIPD_USER)) == NULL)
96 		fatal("getpwnam");
97 
98 	if (chroot(pw->pw_dir) == -1)
99 		fatal("chroot");
100 	if (chdir("/") == -1)
101 		fatal("chdir(\"/\")");
102 
103 	setproctitle("route decision engine");
104 	ripd_process = PROC_RDE_ENGINE;
105 
106 	if (setgroups(1, &pw->pw_gid) ||
107 	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
108 	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
109 		fatal("can't drop privileges");
110 
111 	event_init();
112 
113 	/* setup signal handler */
114 	signal_set(&ev_sigint, SIGINT, rde_sig_handler, NULL);
115 	signal_set(&ev_sigterm, SIGTERM, rde_sig_handler, NULL);
116 	signal_add(&ev_sigint, NULL);
117 	signal_add(&ev_sigterm, NULL);
118 	signal(SIGPIPE, SIG_IGN);
119 	signal(SIGHUP, SIG_IGN);
120 
121 	/* setup pipes */
122 	close(pipe_ripe2rde[0]);
123 	close(pipe_parent2rde[0]);
124 	close(pipe_parent2ripe[0]);
125 	close(pipe_parent2ripe[1]);
126 
127 	if ((iev_ripe = malloc(sizeof(struct imsgev))) == NULL ||
128 	    (iev_main = malloc(sizeof(struct imsgev))) == NULL)
129 		fatal(NULL);
130 	imsg_init(&iev_ripe->ibuf, pipe_ripe2rde[1]);
131 	iev_ripe->handler =  rde_dispatch_imsg;
132 	imsg_init(&iev_main->ibuf, pipe_parent2rde[1]);
133 	iev_main->handler = rde_dispatch_parent;
134 
135 	/* setup event handler */
136 	iev_ripe->events = EV_READ;
137 	event_set(&iev_ripe->ev, iev_ripe->ibuf.fd, iev_ripe->events,
138 	    iev_ripe->handler, iev_ripe);
139 	event_add(&iev_ripe->ev, NULL);
140 
141 	iev_main->events = EV_READ;
142 	event_set(&iev_main->ev, iev_main->ibuf.fd, iev_main->events,
143 	    iev_main->handler, iev_main);
144 	event_add(&iev_main->ev, NULL);
145 	rt_init();
146 
147 	/* remove unneeded config stuff */
148 	while ((r = SIMPLEQ_FIRST(&rdeconf->redist_list)) != NULL) {
149 		SIMPLEQ_REMOVE_HEAD(&rdeconf->redist_list, entry);
150 		free(r);
151 	}
152 
153 	event_dispatch();
154 
155 	rde_shutdown();
156 	/* NOTREACHED */
157 
158 	return (0);
159 }
160 
161 void
162 rde_shutdown(void)
163 {
164 	rt_clear();
165 
166 	msgbuf_clear(&iev_ripe->ibuf.w);
167 	free(iev_ripe);
168 	msgbuf_clear(&iev_main->ibuf.w);
169 	free(iev_main);
170 	free(rdeconf);
171 
172 	log_info("route decision engine exiting");
173 	_exit(0);
174 }
175 
176 int
177 rde_imsg_compose_ripe(int type, u_int32_t peerid, pid_t pid, void *data,
178     u_int16_t datalen)
179 {
180 	return (imsg_compose_event(iev_ripe, type, peerid, pid, -1,
181 		    data, datalen));
182 }
183 
184 /* ARGSUSED */
185 void
186 rde_dispatch_imsg(int fd, short event, void *bula)
187 {
188 	struct imsgev		*iev = bula;
189 	struct imsgbuf		*ibuf = &iev->ibuf;
190 	struct rip_route	 rr;
191 	struct imsg		 imsg;
192 	ssize_t			 n;
193 	int			 shut = 0, verbose;
194 
195 	if (event & EV_READ) {
196 		if ((n = imsg_read(ibuf)) == -1)
197 			fatal("imsg_read error");
198 		if (n == 0)	/* connection closed */
199 			shut = 1;
200 	}
201 	if (event & EV_WRITE) {
202 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
203 			fatal("msgbuf_write");
204 		if (n == 0)	/* connection closed */
205 			shut = 1;
206 	}
207 
208 	for (;;) {
209 		if ((n = imsg_get(ibuf, &imsg)) == -1)
210 			fatal("rde_dispatch_imsg: imsg_read error");
211 		if (n == 0)
212 			break;
213 
214 		switch (imsg.hdr.type) {
215 		case IMSG_ROUTE_FEED:
216 			if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(rr))
217 				fatalx("invalid size of RDE request");
218 
219 			memcpy(&rr, imsg.data, sizeof(rr));
220 
221 			if (rde_check_route(&rr) == -1)
222 				log_debug("rde_dispatch_imsg: "
223 				    "packet malformed\n");
224 			break;
225 		case IMSG_FULL_REQUEST:
226 			bzero(&rr, sizeof(rr));
227 			/*
228 			 * AFI == 0 && metric == INFINITY request the
229 			 * whole routing table
230 			 */
231 			rr.metric = INFINITY;
232 			rde_imsg_compose_ripe(IMSG_REQUEST_ADD, 0,
233 			    0, &rr, sizeof(rr));
234 			rde_imsg_compose_ripe(IMSG_SEND_REQUEST, 0,
235 			    0, NULL, 0);
236 			break;
237 		case IMSG_FULL_RESPONSE:
238 			rt_snap(imsg.hdr.peerid);
239 			rde_imsg_compose_ripe(IMSG_SEND_RESPONSE,
240 			    imsg.hdr.peerid, 0, NULL, 0);
241 			break;
242 		case IMSG_ROUTE_REQUEST:
243 			if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(rr))
244 				fatalx("invalid size of RDE request");
245 
246 			memcpy(&rr, imsg.data, sizeof(rr));
247 
248 			rt_complete(&rr);
249 			rde_imsg_compose_ripe(IMSG_RESPONSE_ADD,
250 			    imsg.hdr.peerid, 0, &rr, sizeof(rr));
251 
252 			break;
253 		case IMSG_ROUTE_REQUEST_END:
254 			rde_imsg_compose_ripe(IMSG_SEND_RESPONSE,
255 			    imsg.hdr.peerid, 0, NULL, 0);
256 			break;
257 		case IMSG_CTL_SHOW_RIB:
258 			rt_dump(imsg.hdr.pid);
259 
260 			imsg_compose_event(iev_ripe, IMSG_CTL_END, 0,
261 			    imsg.hdr.pid, -1, NULL, 0);
262 
263 			break;
264 		case IMSG_CTL_LOG_VERBOSE:
265 			/* already checked by ripe */
266 			memcpy(&verbose, imsg.data, sizeof(verbose));
267 			log_verbose(verbose);
268 			break;
269 		default:
270 			log_debug("rde_dispatch_msg: unexpected imsg %d",
271 			    imsg.hdr.type);
272 			break;
273 		}
274 		imsg_free(&imsg);
275 	}
276 	if (!shut)
277 		imsg_event_add(iev);
278 	else {
279 		/* this pipe is dead, so remove the event handler */
280 		event_del(&iev->ev);
281 		event_loopexit(NULL);
282 	}
283 }
284 
285 /* ARGSUSED */
286 void
287 rde_dispatch_parent(int fd, short event, void *bula)
288 {
289 	struct imsg		 imsg;
290 	struct rt_node		*rt;
291 	struct kroute		 kr;
292 	struct imsgev		*iev = bula;
293 	struct imsgbuf		*ibuf = &iev->ibuf;
294 	ssize_t			 n;
295 	int			 shut = 0;
296 
297 	if (event & EV_READ) {
298 		if ((n = imsg_read(ibuf)) == -1)
299 			fatal("imsg_read error");
300 		if (n == 0)	/* connection closed */
301 			shut = 1;
302 	}
303 	if (event & EV_WRITE) {
304 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
305 			fatal("msgbuf_write");
306 		if (n == 0)	/* connection closed */
307 			shut = 1;
308 	}
309 
310 	for (;;) {
311 		if ((n = imsg_get(ibuf, &imsg)) == -1)
312 			fatal("rde_dispatch_parent: imsg_read error");
313 		if (n == 0)
314 			break;
315 
316 		switch (imsg.hdr.type) {
317 		case IMSG_NETWORK_ADD:
318 			if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(kr)) {
319 				log_warnx("rde_dispatch: wrong imsg len");
320 				break;
321 			}
322 
323 			memcpy(&kr, imsg.data, sizeof(kr));
324 
325 			rt = rt_new_kr(&kr);
326 			rt_insert(rt);
327 			break;
328 		case IMSG_NETWORK_DEL:
329 			if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(kr)) {
330 				log_warnx("rde_dispatch: wrong imsg len");
331 				break;
332 			}
333 			memcpy(&kr, imsg.data, sizeof(kr));
334 
335 			if ((rt = rt_find(kr.prefix.s_addr,
336 			    kr.netmask.s_addr)) != NULL)
337 				rt_remove(rt);
338 			break;
339 		default:
340 			log_debug("rde_dispatch_parent: unexpected imsg %d",
341 			    imsg.hdr.type);
342 			break;
343 		}
344 		imsg_free(&imsg);
345 	}
346 	if (!shut)
347 		imsg_event_add(iev);
348 	else {
349 		/* this pipe is dead, so remove the event handler */
350 		event_del(&iev->ev);
351 		event_loopexit(NULL);
352 	}
353 }
354 
355 void
356 rde_send_change_kroute(struct rt_node *r)
357 {
358 	struct kroute	 kr;
359 
360 	bzero(&kr, sizeof(kr));
361 	kr.prefix.s_addr = r->prefix.s_addr;
362 	kr.nexthop.s_addr = r->nexthop.s_addr;
363 	kr.netmask.s_addr = r->netmask.s_addr;
364 	kr.metric = r->metric;
365 	kr.flags = r->flags;
366 	kr.ifindex = r->ifindex;
367 
368 	imsg_compose_event(iev_main, IMSG_KROUTE_CHANGE, 0, 0, -1,
369 	    &kr, sizeof(kr));
370 }
371 
372 void
373 rde_send_delete_kroute(struct rt_node *r)
374 {
375 	struct kroute	 kr;
376 
377 	bzero(&kr, sizeof(kr));
378 	kr.prefix.s_addr = r->prefix.s_addr;
379 	kr.nexthop.s_addr = r->nexthop.s_addr;
380 	kr.netmask.s_addr = r->netmask.s_addr;
381 	kr.metric = r->metric;
382 	kr.flags = r->flags;
383 	kr.ifindex = r->ifindex;
384 
385 	imsg_compose_event(iev_main, IMSG_KROUTE_DELETE, 0, 0, -1,
386 	    &kr, sizeof(kr));
387 }
388 
389 int
390 rde_check_route(struct rip_route *e)
391 {
392 	struct timeval	 tv, now;
393 	struct rt_node	*rn;
394 	struct iface	*iface;
395 	u_int8_t	 metric;
396 
397 	if ((e->nexthop.s_addr & htonl(IN_CLASSA_NET)) ==
398 	    htonl(INADDR_LOOPBACK & IN_CLASSA_NET) ||
399 	    e->nexthop.s_addr == INADDR_ANY)
400 		return (-1);
401 
402 	if ((iface = if_find_index(e->ifindex)) == NULL)
403 		return (-1);
404 
405 	metric = MINIMUM(INFINITY, e->metric + iface->cost);
406 
407 	if ((rn = rt_find(e->address.s_addr, e->mask.s_addr)) == NULL) {
408 		if (metric >= INFINITY)
409 			return (0);
410 		rn = rt_new_rr(e, metric);
411 		rt_insert(rn);
412 		rde_send_change_kroute(rn);
413 		route_start_timeout(rn);
414 		triggered_update(rn);
415 	} else {
416 		/*
417 		 * XXX don't we have to track all incoming routes?
418 		 * what happens if the kernel route is removed later.
419 		 */
420 		if (rn->flags & F_KERNEL)
421 			return (0);
422 
423 		if (metric < rn->metric) {
424 			rn->metric = metric;
425 			rn->nexthop.s_addr = e->nexthop.s_addr;
426 			rn->ifindex = e->ifindex;
427 			rde_send_change_kroute(rn);
428 			triggered_update(rn);
429 		} else if (e->nexthop.s_addr == rn->nexthop.s_addr &&
430 		    metric > rn->metric) {
431 				rn->metric = metric;
432 				rde_send_change_kroute(rn);
433 				triggered_update(rn);
434 				if (rn->metric == INFINITY)
435 					route_start_garbage(rn);
436 		} else if (e->nexthop.s_addr != rn->nexthop.s_addr &&
437 		    metric == rn->metric) {
438 			/* If the new metric is the same as the old one,
439 			 * examine the timeout for the existing route.  If it
440 			 * is at least halfway to the expiration point, switch
441 			 * to the new route.
442 			 */
443 			timerclear(&tv);
444 			gettimeofday(&now, NULL);
445 			evtimer_pending(&rn->timeout_timer, &tv);
446 			if (tv.tv_sec - now.tv_sec < ROUTE_TIMEOUT / 2) {
447 				rn->nexthop.s_addr = e->nexthop.s_addr;
448 				rn->ifindex = e->ifindex;
449 				rde_send_change_kroute(rn);
450 			}
451 		}
452 
453 		if (e->nexthop.s_addr == rn->nexthop.s_addr &&
454 		    rn->metric < INFINITY)
455 			route_reset_timers(rn);
456 	}
457 
458 	return (0);
459 }
460 
461 void
462 triggered_update(struct rt_node *rn)
463 {
464 	struct rip_route	 rr;
465 
466 	rr.address.s_addr = rn->prefix.s_addr;
467 	rr.mask.s_addr = rn->netmask.s_addr;
468 	rr.nexthop.s_addr = rn->nexthop.s_addr;
469 	rr.metric = rn->metric;
470 	rr.ifindex = rn->ifindex;
471 
472 	rde_imsg_compose_ripe(IMSG_SEND_TRIGGERED_UPDATE, 0, 0, &rr,
473 	    sizeof(struct rip_route));
474 }
475