xref: /openbsd-src/usr.sbin/bgpd/session.c (revision c1a45aed656e7d5627c30c92421893a76f370ccb)
1 /*	$OpenBSD: session.c,v 1.427 2022/02/23 11:20:35 claudio Exp $ */
2 
3 /*
4  * Copyright (c) 2003, 2004, 2005 Henning Brauer <henning@openbsd.org>
5  * Copyright (c) 2017 Peter van Dijk <peter.van.dijk@powerdns.com>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include <sys/types.h>
21 
22 #include <sys/mman.h>
23 #include <sys/socket.h>
24 #include <sys/time.h>
25 #include <sys/resource.h>
26 #include <sys/un.h>
27 #include <netinet/in.h>
28 #include <netinet/ip.h>
29 #include <netinet/tcp.h>
30 #include <arpa/inet.h>
31 #include <limits.h>
32 
33 #include <err.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <ifaddrs.h>
37 #include <poll.h>
38 #include <pwd.h>
39 #include <signal.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <syslog.h>
44 #include <unistd.h>
45 
46 #include "bgpd.h"
47 #include "session.h"
48 #include "log.h"
49 
50 #define PFD_PIPE_MAIN		0
51 #define PFD_PIPE_ROUTE		1
52 #define PFD_PIPE_ROUTE_CTL	2
53 #define PFD_SOCK_CTL		3
54 #define PFD_SOCK_RCTL		4
55 #define PFD_LISTENERS_START	5
56 
57 void	session_sighdlr(int);
58 int	setup_listeners(u_int *);
59 void	init_peer(struct peer *);
60 void	start_timer_holdtime(struct peer *);
61 void	start_timer_keepalive(struct peer *);
62 void	session_close_connection(struct peer *);
63 void	change_state(struct peer *, enum session_state, enum session_events);
64 int	session_setup_socket(struct peer *);
65 void	session_accept(int);
66 int	session_connect(struct peer *);
67 void	session_tcp_established(struct peer *);
68 void	session_capa_ann_none(struct peer *);
69 int	session_capa_add(struct ibuf *, uint8_t, uint8_t);
70 int	session_capa_add_mp(struct ibuf *, uint8_t);
71 int	session_capa_add_afi(struct peer *, struct ibuf *, uint8_t, uint8_t);
72 struct bgp_msg	*session_newmsg(enum msg_type, uint16_t);
73 int	session_sendmsg(struct bgp_msg *, struct peer *);
74 void	session_open(struct peer *);
75 void	session_keepalive(struct peer *);
76 void	session_update(uint32_t, void *, size_t);
77 void	session_notification(struct peer *, uint8_t, uint8_t, void *,
78 	    ssize_t);
79 void	session_rrefresh(struct peer *, uint8_t, uint8_t);
80 int	session_graceful_restart(struct peer *);
81 int	session_graceful_stop(struct peer *);
82 int	session_dispatch_msg(struct pollfd *, struct peer *);
83 void	session_process_msg(struct peer *);
84 int	parse_header(struct peer *, u_char *, uint16_t *, uint8_t *);
85 int	parse_open(struct peer *);
86 int	parse_update(struct peer *);
87 int	parse_rrefresh(struct peer *);
88 int	parse_notification(struct peer *);
89 int	parse_capabilities(struct peer *, u_char *, uint16_t, uint32_t *);
90 int	capa_neg_calc(struct peer *);
91 void	session_dispatch_imsg(struct imsgbuf *, int, u_int *);
92 void	session_up(struct peer *);
93 void	session_down(struct peer *);
94 int	imsg_rde(int, uint32_t, void *, uint16_t);
95 void	session_demote(struct peer *, int);
96 void	merge_peers(struct bgpd_config *, struct bgpd_config *);
97 
98 int		 la_cmp(struct listen_addr *, struct listen_addr *);
99 void		 session_template_clone(struct peer *, struct sockaddr *,
100 		    uint32_t, uint32_t);
101 int		 session_match_mask(struct peer *, struct bgpd_addr *);
102 
103 static struct bgpd_config	*conf, *nconf;
104 static struct imsgbuf		*ibuf_rde;
105 static struct imsgbuf		*ibuf_rde_ctl;
106 static struct imsgbuf		*ibuf_main;
107 
108 struct bgpd_sysdep	 sysdep;
109 volatile sig_atomic_t	 session_quit;
110 int			 pending_reconf;
111 int			 csock = -1, rcsock = -1;
112 u_int			 peer_cnt;
113 
114 struct mrt_head		 mrthead;
115 time_t			 pauseaccept;
116 
117 static inline int
118 peer_compare(const struct peer *a, const struct peer *b)
119 {
120 	return a->conf.id - b->conf.id;
121 }
122 
123 RB_GENERATE(peer_head, peer, entry, peer_compare);
124 
125 void
126 session_sighdlr(int sig)
127 {
128 	switch (sig) {
129 	case SIGINT:
130 	case SIGTERM:
131 		session_quit = 1;
132 		break;
133 	}
134 }
135 
136 int
137 setup_listeners(u_int *la_cnt)
138 {
139 	int			 ttl = 255;
140 	struct listen_addr	*la;
141 	u_int			 cnt = 0;
142 
143 	TAILQ_FOREACH(la, conf->listen_addrs, entry) {
144 		la->reconf = RECONF_NONE;
145 		cnt++;
146 
147 		if (la->flags & LISTENER_LISTENING)
148 			continue;
149 
150 		if (la->fd == -1) {
151 			log_warn("cannot establish listener on %s: invalid fd",
152 			    log_sockaddr((struct sockaddr *)&la->sa,
153 			    la->sa_len));
154 			continue;
155 		}
156 
157 		if (tcp_md5_prep_listener(la, &conf->peers) == -1)
158 			fatal("tcp_md5_prep_listener");
159 
160 		/* set ttl to 255 so that ttl-security works */
161 		if (la->sa.ss_family == AF_INET && setsockopt(la->fd,
162 		    IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) == -1) {
163 			log_warn("setup_listeners setsockopt TTL");
164 			continue;
165 		}
166 		if (la->sa.ss_family == AF_INET6 && setsockopt(la->fd,
167 		    IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)) == -1) {
168 			log_warn("setup_listeners setsockopt hoplimit");
169 			continue;
170 		}
171 
172 		if (listen(la->fd, MAX_BACKLOG)) {
173 			close(la->fd);
174 			fatal("listen");
175 		}
176 
177 		la->flags |= LISTENER_LISTENING;
178 
179 		log_info("listening on %s",
180 		    log_sockaddr((struct sockaddr *)&la->sa, la->sa_len));
181 	}
182 
183 	*la_cnt = cnt;
184 
185 	return (0);
186 }
187 
188 void
189 session_main(int debug, int verbose)
190 {
191 	int			 timeout;
192 	unsigned int		 i, j, idx_peers, idx_listeners, idx_mrts;
193 	u_int			 pfd_elms = 0, peer_l_elms = 0, mrt_l_elms = 0;
194 	u_int			 listener_cnt, ctl_cnt, mrt_cnt;
195 	u_int			 new_cnt;
196 	struct passwd		*pw;
197 	struct peer		*p, **peer_l = NULL, *next;
198 	struct mrt		*m, *xm, **mrt_l = NULL;
199 	struct pollfd		*pfd = NULL;
200 	struct listen_addr	*la;
201 	void			*newp;
202 	time_t			 now;
203 	short			 events;
204 
205 	log_init(debug, LOG_DAEMON);
206 	log_setverbose(verbose);
207 
208 	log_procinit(log_procnames[PROC_SE]);
209 
210 	if ((pw = getpwnam(BGPD_USER)) == NULL)
211 		fatal(NULL);
212 
213 	if (chroot(pw->pw_dir) == -1)
214 		fatal("chroot");
215 	if (chdir("/") == -1)
216 		fatal("chdir(\"/\")");
217 
218 	setproctitle("session engine");
219 
220 	if (setgroups(1, &pw->pw_gid) ||
221 	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
222 	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
223 		fatal("can't drop privileges");
224 
225 	if (pledge("stdio inet recvfd", NULL) == -1)
226 		fatal("pledge");
227 
228 	signal(SIGTERM, session_sighdlr);
229 	signal(SIGINT, session_sighdlr);
230 	signal(SIGPIPE, SIG_IGN);
231 	signal(SIGHUP, SIG_IGN);
232 	signal(SIGALRM, SIG_IGN);
233 	signal(SIGUSR1, SIG_IGN);
234 
235 	if ((ibuf_main = malloc(sizeof(struct imsgbuf))) == NULL)
236 		fatal(NULL);
237 	imsg_init(ibuf_main, 3);
238 
239 	LIST_INIT(&mrthead);
240 	listener_cnt = 0;
241 	peer_cnt = 0;
242 	ctl_cnt = 0;
243 
244 	conf = new_config();
245 	log_info("session engine ready");
246 
247 	while (session_quit == 0) {
248 		/* check for peers to be initialized or deleted */
249 		if (!pending_reconf) {
250 			RB_FOREACH_SAFE(p, peer_head, &conf->peers, next) {
251 				/* cloned peer that idled out? */
252 				if (p->template && (p->state == STATE_IDLE ||
253 				    p->state == STATE_ACTIVE) &&
254 				    getmonotime() - p->stats.last_updown >=
255 				    INTERVAL_HOLD_CLONED)
256 					p->reconf_action = RECONF_DELETE;
257 
258 				/* new peer that needs init? */
259 				if (p->state == STATE_NONE)
260 					init_peer(p);
261 
262 				/* reinit due? */
263 				if (p->reconf_action == RECONF_REINIT) {
264 					session_stop(p, ERR_CEASE_ADMIN_RESET);
265 					if (!p->conf.down)
266 						timer_set(&p->timers,
267 						    Timer_IdleHold, 0);
268 				}
269 
270 				/* deletion due? */
271 				if (p->reconf_action == RECONF_DELETE) {
272 					if (p->demoted)
273 						session_demote(p, -1);
274 					p->conf.demote_group[0] = 0;
275 					session_stop(p, ERR_CEASE_PEER_UNCONF);
276 					timer_remove_all(&p->timers);
277 					tcp_md5_del_listener(conf, p);
278 					log_peer_warnx(&p->conf, "removed");
279 					RB_REMOVE(peer_head, &conf->peers, p);
280 					free(p);
281 					peer_cnt--;
282 					continue;
283 				}
284 				p->reconf_action = RECONF_NONE;
285 			}
286 		}
287 
288 		if (peer_cnt > peer_l_elms) {
289 			if ((newp = reallocarray(peer_l, peer_cnt,
290 			    sizeof(struct peer *))) == NULL) {
291 				/* panic for now  */
292 				log_warn("could not resize peer_l from %u -> %u"
293 				    " entries", peer_l_elms, peer_cnt);
294 				fatalx("exiting");
295 			}
296 			peer_l = newp;
297 			peer_l_elms = peer_cnt;
298 		}
299 
300 		mrt_cnt = 0;
301 		for (m = LIST_FIRST(&mrthead); m != NULL; m = xm) {
302 			xm = LIST_NEXT(m, entry);
303 			if (m->state == MRT_STATE_REMOVE) {
304 				mrt_clean(m);
305 				LIST_REMOVE(m, entry);
306 				free(m);
307 				continue;
308 			}
309 			if (m->wbuf.queued)
310 				mrt_cnt++;
311 		}
312 
313 		if (mrt_cnt > mrt_l_elms) {
314 			if ((newp = reallocarray(mrt_l, mrt_cnt,
315 			    sizeof(struct mrt *))) == NULL) {
316 				/* panic for now  */
317 				log_warn("could not resize mrt_l from %u -> %u"
318 				    " entries", mrt_l_elms, mrt_cnt);
319 				fatalx("exiting");
320 			}
321 			mrt_l = newp;
322 			mrt_l_elms = mrt_cnt;
323 		}
324 
325 		new_cnt = PFD_LISTENERS_START + listener_cnt + peer_cnt +
326 		    ctl_cnt + mrt_cnt;
327 		if (new_cnt > pfd_elms) {
328 			if ((newp = reallocarray(pfd, new_cnt,
329 			    sizeof(struct pollfd))) == NULL) {
330 				/* panic for now  */
331 				log_warn("could not resize pfd from %u -> %u"
332 				    " entries", pfd_elms, new_cnt);
333 				fatalx("exiting");
334 			}
335 			pfd = newp;
336 			pfd_elms = new_cnt;
337 		}
338 
339 		bzero(pfd, sizeof(struct pollfd) * pfd_elms);
340 
341 		set_pollfd(&pfd[PFD_PIPE_MAIN], ibuf_main);
342 		set_pollfd(&pfd[PFD_PIPE_ROUTE], ibuf_rde);
343 		set_pollfd(&pfd[PFD_PIPE_ROUTE_CTL], ibuf_rde_ctl);
344 
345 		if (pauseaccept == 0) {
346 			pfd[PFD_SOCK_CTL].fd = csock;
347 			pfd[PFD_SOCK_CTL].events = POLLIN;
348 			pfd[PFD_SOCK_RCTL].fd = rcsock;
349 			pfd[PFD_SOCK_RCTL].events = POLLIN;
350 		} else {
351 			pfd[PFD_SOCK_CTL].fd = -1;
352 			pfd[PFD_SOCK_RCTL].fd = -1;
353 		}
354 
355 		i = PFD_LISTENERS_START;
356 		TAILQ_FOREACH(la, conf->listen_addrs, entry) {
357 			if (pauseaccept == 0) {
358 				pfd[i].fd = la->fd;
359 				pfd[i].events = POLLIN;
360 			} else
361 				pfd[i].fd = -1;
362 			i++;
363 		}
364 		idx_listeners = i;
365 		timeout = 240;	/* loop every 240s at least */
366 
367 		now = getmonotime();
368 		RB_FOREACH(p, peer_head, &conf->peers) {
369 			time_t	nextaction;
370 			struct timer *pt;
371 
372 			/* check timers */
373 			if ((pt = timer_nextisdue(&p->timers, now)) != NULL) {
374 				switch (pt->type) {
375 				case Timer_Hold:
376 					bgp_fsm(p, EVNT_TIMER_HOLDTIME);
377 					break;
378 				case Timer_SendHold:
379 					bgp_fsm(p, EVNT_TIMER_SENDHOLD);
380 					break;
381 				case Timer_ConnectRetry:
382 					bgp_fsm(p, EVNT_TIMER_CONNRETRY);
383 					break;
384 				case Timer_Keepalive:
385 					bgp_fsm(p, EVNT_TIMER_KEEPALIVE);
386 					break;
387 				case Timer_IdleHold:
388 					bgp_fsm(p, EVNT_START);
389 					break;
390 				case Timer_IdleHoldReset:
391 					p->IdleHoldTime =
392 					    INTERVAL_IDLE_HOLD_INITIAL;
393 					p->errcnt = 0;
394 					timer_stop(&p->timers,
395 					    Timer_IdleHoldReset);
396 					break;
397 				case Timer_CarpUndemote:
398 					timer_stop(&p->timers,
399 					    Timer_CarpUndemote);
400 					if (p->demoted &&
401 					    p->state == STATE_ESTABLISHED)
402 						session_demote(p, -1);
403 					break;
404 				case Timer_RestartTimeout:
405 					timer_stop(&p->timers,
406 					    Timer_RestartTimeout);
407 					session_graceful_stop(p);
408 					break;
409 				default:
410 					fatalx("King Bula lost in time");
411 				}
412 			}
413 			if ((nextaction = timer_nextduein(&p->timers,
414 			    now)) != -1 && nextaction < timeout)
415 				timeout = nextaction;
416 
417 			/* are we waiting for a write? */
418 			events = POLLIN;
419 			if (p->wbuf.queued > 0 || p->state == STATE_CONNECT)
420 				events |= POLLOUT;
421 			/* is there still work to do? */
422 			if (p->rpending && p->rbuf && p->rbuf->wpos)
423 				timeout = 0;
424 
425 			/* poll events */
426 			if (p->fd != -1 && events != 0) {
427 				pfd[i].fd = p->fd;
428 				pfd[i].events = events;
429 				peer_l[i - idx_listeners] = p;
430 				i++;
431 			}
432 		}
433 
434 		idx_peers = i;
435 
436 		LIST_FOREACH(m, &mrthead, entry)
437 			if (m->wbuf.queued) {
438 				pfd[i].fd = m->wbuf.fd;
439 				pfd[i].events = POLLOUT;
440 				mrt_l[i - idx_peers] = m;
441 				i++;
442 			}
443 
444 		idx_mrts = i;
445 
446 		i += control_fill_pfds(pfd + i, pfd_elms -i);
447 
448 		if (i > pfd_elms)
449 			fatalx("poll pfd overflow");
450 
451 		if (pauseaccept && timeout > 1)
452 			timeout = 1;
453 		if (timeout < 0)
454 			timeout = 0;
455 		if (poll(pfd, i, timeout * 1000) == -1) {
456 			if (errno == EINTR)
457 				continue;
458 			fatal("poll error");
459 		}
460 
461 		/*
462 		 * If we previously saw fd exhaustion, we stop accept()
463 		 * for 1 second to throttle the accept() loop.
464 		 */
465 		if (pauseaccept && getmonotime() > pauseaccept + 1)
466 			pauseaccept = 0;
467 
468 		if (handle_pollfd(&pfd[PFD_PIPE_MAIN], ibuf_main) == -1) {
469 			log_warnx("SE: Lost connection to parent");
470 			session_quit = 1;
471 			continue;
472 		} else
473 			session_dispatch_imsg(ibuf_main, PFD_PIPE_MAIN,
474 			    &listener_cnt);
475 
476 		if (handle_pollfd(&pfd[PFD_PIPE_ROUTE], ibuf_rde) == -1) {
477 			log_warnx("SE: Lost connection to RDE");
478 			msgbuf_clear(&ibuf_rde->w);
479 			free(ibuf_rde);
480 			ibuf_rde = NULL;
481 		} else
482 			session_dispatch_imsg(ibuf_rde, PFD_PIPE_ROUTE,
483 			    &listener_cnt);
484 
485 		if (handle_pollfd(&pfd[PFD_PIPE_ROUTE_CTL], ibuf_rde_ctl) ==
486 		    -1) {
487 			log_warnx("SE: Lost connection to RDE control");
488 			msgbuf_clear(&ibuf_rde_ctl->w);
489 			free(ibuf_rde_ctl);
490 			ibuf_rde_ctl = NULL;
491 		} else
492 			session_dispatch_imsg(ibuf_rde_ctl, PFD_PIPE_ROUTE_CTL,
493 			    &listener_cnt);
494 
495 		if (pfd[PFD_SOCK_CTL].revents & POLLIN)
496 			ctl_cnt += control_accept(csock, 0);
497 
498 		if (pfd[PFD_SOCK_RCTL].revents & POLLIN)
499 			ctl_cnt += control_accept(rcsock, 1);
500 
501 		for (j = PFD_LISTENERS_START; j < idx_listeners; j++)
502 			if (pfd[j].revents & POLLIN)
503 				session_accept(pfd[j].fd);
504 
505 		for (; j < idx_peers; j++)
506 			session_dispatch_msg(&pfd[j],
507 			    peer_l[j - idx_listeners]);
508 
509 		RB_FOREACH(p, peer_head, &conf->peers)
510 			if (p->rbuf && p->rbuf->wpos)
511 				session_process_msg(p);
512 
513 		for (; j < idx_mrts; j++)
514 			if (pfd[j].revents & POLLOUT)
515 				mrt_write(mrt_l[j - idx_peers]);
516 
517 		for (; j < i; j++)
518 			ctl_cnt -= control_dispatch_msg(&pfd[j], &conf->peers);
519 	}
520 
521 	RB_FOREACH_SAFE(p, peer_head, &conf->peers, next) {
522 		RB_REMOVE(peer_head, &conf->peers, p);
523 		strlcpy(p->conf.reason,
524 		    "bgpd shutting down",
525 		    sizeof(p->conf.reason));
526 		session_stop(p, ERR_CEASE_ADMIN_DOWN);
527 		timer_remove_all(&p->timers);
528 		free(p);
529 	}
530 
531 	while ((m = LIST_FIRST(&mrthead)) != NULL) {
532 		mrt_clean(m);
533 		LIST_REMOVE(m, entry);
534 		free(m);
535 	}
536 
537 	free_config(conf);
538 	free(peer_l);
539 	free(mrt_l);
540 	free(pfd);
541 
542 	/* close pipes */
543 	if (ibuf_rde) {
544 		msgbuf_write(&ibuf_rde->w);
545 		msgbuf_clear(&ibuf_rde->w);
546 		close(ibuf_rde->fd);
547 		free(ibuf_rde);
548 	}
549 	if (ibuf_rde_ctl) {
550 		msgbuf_clear(&ibuf_rde_ctl->w);
551 		close(ibuf_rde_ctl->fd);
552 		free(ibuf_rde_ctl);
553 	}
554 	msgbuf_write(&ibuf_main->w);
555 	msgbuf_clear(&ibuf_main->w);
556 	close(ibuf_main->fd);
557 	free(ibuf_main);
558 
559 	control_shutdown(csock);
560 	control_shutdown(rcsock);
561 	log_info("session engine exiting");
562 	exit(0);
563 }
564 
565 void
566 init_peer(struct peer *p)
567 {
568 	TAILQ_INIT(&p->timers);
569 	p->fd = p->wbuf.fd = -1;
570 
571 	if (p->conf.if_depend[0])
572 		imsg_compose(ibuf_main, IMSG_IFINFO, 0, 0, -1,
573 		    p->conf.if_depend, sizeof(p->conf.if_depend));
574 	else
575 		p->depend_ok = 1;
576 
577 	peer_cnt++;
578 
579 	change_state(p, STATE_IDLE, EVNT_NONE);
580 	if (p->conf.down)
581 		timer_stop(&p->timers, Timer_IdleHold); /* no autostart */
582 	else
583 		timer_set(&p->timers, Timer_IdleHold, 0); /* start ASAP */
584 
585 	/*
586 	 * on startup, demote if requested.
587 	 * do not handle new peers. they must reach ESTABLISHED beforehands.
588 	 * peers added at runtime have reconf_action set to RECONF_REINIT.
589 	 */
590 	if (p->reconf_action != RECONF_REINIT && p->conf.demote_group[0])
591 		session_demote(p, +1);
592 }
593 
594 void
595 bgp_fsm(struct peer *peer, enum session_events event)
596 {
597 	switch (peer->state) {
598 	case STATE_NONE:
599 		/* nothing */
600 		break;
601 	case STATE_IDLE:
602 		switch (event) {
603 		case EVNT_START:
604 			timer_stop(&peer->timers, Timer_Hold);
605 			timer_stop(&peer->timers, Timer_SendHold);
606 			timer_stop(&peer->timers, Timer_Keepalive);
607 			timer_stop(&peer->timers, Timer_IdleHold);
608 
609 			/* allocate read buffer */
610 			peer->rbuf = calloc(1, sizeof(struct ibuf_read));
611 			if (peer->rbuf == NULL)
612 				fatal(NULL);
613 
614 			/* init write buffer */
615 			msgbuf_init(&peer->wbuf);
616 
617 			peer->stats.last_sent_errcode = 0;
618 			peer->stats.last_sent_suberr = 0;
619 			peer->stats.last_rcvd_errcode = 0;
620 			peer->stats.last_rcvd_suberr = 0;
621 
622 			if (!peer->depend_ok)
623 				timer_stop(&peer->timers, Timer_ConnectRetry);
624 			else if (peer->passive || peer->conf.passive ||
625 			    peer->conf.template) {
626 				change_state(peer, STATE_ACTIVE, event);
627 				timer_stop(&peer->timers, Timer_ConnectRetry);
628 			} else {
629 				change_state(peer, STATE_CONNECT, event);
630 				timer_set(&peer->timers, Timer_ConnectRetry,
631 				    conf->connectretry);
632 				session_connect(peer);
633 			}
634 			peer->passive = 0;
635 			break;
636 		default:
637 			/* ignore */
638 			break;
639 		}
640 		break;
641 	case STATE_CONNECT:
642 		switch (event) {
643 		case EVNT_START:
644 			/* ignore */
645 			break;
646 		case EVNT_CON_OPEN:
647 			session_tcp_established(peer);
648 			session_open(peer);
649 			timer_stop(&peer->timers, Timer_ConnectRetry);
650 			peer->holdtime = INTERVAL_HOLD_INITIAL;
651 			start_timer_holdtime(peer);
652 			change_state(peer, STATE_OPENSENT, event);
653 			break;
654 		case EVNT_CON_OPENFAIL:
655 			timer_set(&peer->timers, Timer_ConnectRetry,
656 			    conf->connectretry);
657 			session_close_connection(peer);
658 			change_state(peer, STATE_ACTIVE, event);
659 			break;
660 		case EVNT_TIMER_CONNRETRY:
661 			timer_set(&peer->timers, Timer_ConnectRetry,
662 			    conf->connectretry);
663 			session_connect(peer);
664 			break;
665 		default:
666 			change_state(peer, STATE_IDLE, event);
667 			break;
668 		}
669 		break;
670 	case STATE_ACTIVE:
671 		switch (event) {
672 		case EVNT_START:
673 			/* ignore */
674 			break;
675 		case EVNT_CON_OPEN:
676 			session_tcp_established(peer);
677 			session_open(peer);
678 			timer_stop(&peer->timers, Timer_ConnectRetry);
679 			peer->holdtime = INTERVAL_HOLD_INITIAL;
680 			start_timer_holdtime(peer);
681 			change_state(peer, STATE_OPENSENT, event);
682 			break;
683 		case EVNT_CON_OPENFAIL:
684 			timer_set(&peer->timers, Timer_ConnectRetry,
685 			    conf->connectretry);
686 			session_close_connection(peer);
687 			change_state(peer, STATE_ACTIVE, event);
688 			break;
689 		case EVNT_TIMER_CONNRETRY:
690 			timer_set(&peer->timers, Timer_ConnectRetry,
691 			    peer->holdtime);
692 			change_state(peer, STATE_CONNECT, event);
693 			session_connect(peer);
694 			break;
695 		default:
696 			change_state(peer, STATE_IDLE, event);
697 			break;
698 		}
699 		break;
700 	case STATE_OPENSENT:
701 		switch (event) {
702 		case EVNT_START:
703 			/* ignore */
704 			break;
705 		case EVNT_STOP:
706 			change_state(peer, STATE_IDLE, event);
707 			break;
708 		case EVNT_CON_CLOSED:
709 			session_close_connection(peer);
710 			timer_set(&peer->timers, Timer_ConnectRetry,
711 			    conf->connectretry);
712 			change_state(peer, STATE_ACTIVE, event);
713 			break;
714 		case EVNT_CON_FATAL:
715 			change_state(peer, STATE_IDLE, event);
716 			break;
717 		case EVNT_TIMER_HOLDTIME:
718 		case EVNT_TIMER_SENDHOLD:
719 			session_notification(peer, ERR_HOLDTIMEREXPIRED,
720 			    0, NULL, 0);
721 			change_state(peer, STATE_IDLE, event);
722 			break;
723 		case EVNT_RCVD_OPEN:
724 			/* parse_open calls change_state itself on failure */
725 			if (parse_open(peer))
726 				break;
727 			session_keepalive(peer);
728 			change_state(peer, STATE_OPENCONFIRM, event);
729 			break;
730 		case EVNT_RCVD_NOTIFICATION:
731 			if (parse_notification(peer)) {
732 				change_state(peer, STATE_IDLE, event);
733 				/* don't punish, capa negotiation */
734 				timer_set(&peer->timers, Timer_IdleHold, 0);
735 				peer->IdleHoldTime /= 2;
736 			} else
737 				change_state(peer, STATE_IDLE, event);
738 			break;
739 		default:
740 			session_notification(peer,
741 			    ERR_FSM, ERR_FSM_UNEX_OPENSENT, NULL, 0);
742 			change_state(peer, STATE_IDLE, event);
743 			break;
744 		}
745 		break;
746 	case STATE_OPENCONFIRM:
747 		switch (event) {
748 		case EVNT_START:
749 			/* ignore */
750 			break;
751 		case EVNT_STOP:
752 			change_state(peer, STATE_IDLE, event);
753 			break;
754 		case EVNT_CON_CLOSED:
755 		case EVNT_CON_FATAL:
756 			change_state(peer, STATE_IDLE, event);
757 			break;
758 		case EVNT_TIMER_HOLDTIME:
759 		case EVNT_TIMER_SENDHOLD:
760 			session_notification(peer, ERR_HOLDTIMEREXPIRED,
761 			    0, NULL, 0);
762 			change_state(peer, STATE_IDLE, event);
763 			break;
764 		case EVNT_TIMER_KEEPALIVE:
765 			session_keepalive(peer);
766 			break;
767 		case EVNT_RCVD_KEEPALIVE:
768 			start_timer_holdtime(peer);
769 			change_state(peer, STATE_ESTABLISHED, event);
770 			break;
771 		case EVNT_RCVD_NOTIFICATION:
772 			parse_notification(peer);
773 			change_state(peer, STATE_IDLE, event);
774 			break;
775 		default:
776 			session_notification(peer,
777 			    ERR_FSM, ERR_FSM_UNEX_OPENCONFIRM, NULL, 0);
778 			change_state(peer, STATE_IDLE, event);
779 			break;
780 		}
781 		break;
782 	case STATE_ESTABLISHED:
783 		switch (event) {
784 		case EVNT_START:
785 			/* ignore */
786 			break;
787 		case EVNT_STOP:
788 			change_state(peer, STATE_IDLE, event);
789 			break;
790 		case EVNT_CON_CLOSED:
791 		case EVNT_CON_FATAL:
792 			change_state(peer, STATE_IDLE, event);
793 			break;
794 		case EVNT_TIMER_HOLDTIME:
795 		case EVNT_TIMER_SENDHOLD:
796 			session_notification(peer, ERR_HOLDTIMEREXPIRED,
797 			    0, NULL, 0);
798 			change_state(peer, STATE_IDLE, event);
799 			break;
800 		case EVNT_TIMER_KEEPALIVE:
801 			session_keepalive(peer);
802 			break;
803 		case EVNT_RCVD_KEEPALIVE:
804 			start_timer_holdtime(peer);
805 			break;
806 		case EVNT_RCVD_UPDATE:
807 			start_timer_holdtime(peer);
808 			if (parse_update(peer))
809 				change_state(peer, STATE_IDLE, event);
810 			else
811 				start_timer_holdtime(peer);
812 			break;
813 		case EVNT_RCVD_NOTIFICATION:
814 			parse_notification(peer);
815 			change_state(peer, STATE_IDLE, event);
816 			break;
817 		default:
818 			session_notification(peer,
819 			    ERR_FSM, ERR_FSM_UNEX_ESTABLISHED, NULL, 0);
820 			change_state(peer, STATE_IDLE, event);
821 			break;
822 		}
823 		break;
824 	}
825 }
826 
827 void
828 start_timer_holdtime(struct peer *peer)
829 {
830 	if (peer->holdtime > 0)
831 		timer_set(&peer->timers, Timer_Hold, peer->holdtime);
832 	else
833 		timer_stop(&peer->timers, Timer_Hold);
834 }
835 
836 void
837 start_timer_keepalive(struct peer *peer)
838 {
839 	if (peer->holdtime > 0)
840 		timer_set(&peer->timers, Timer_Keepalive, peer->holdtime / 3);
841 	else
842 		timer_stop(&peer->timers, Timer_Keepalive);
843 }
844 
845 void
846 session_close_connection(struct peer *peer)
847 {
848 	if (peer->fd != -1) {
849 		close(peer->fd);
850 		pauseaccept = 0;
851 	}
852 	peer->fd = peer->wbuf.fd = -1;
853 }
854 
855 void
856 change_state(struct peer *peer, enum session_state state,
857     enum session_events event)
858 {
859 	struct mrt	*mrt;
860 
861 	switch (state) {
862 	case STATE_IDLE:
863 		/* carp demotion first. new peers handled in init_peer */
864 		if (peer->state == STATE_ESTABLISHED &&
865 		    peer->conf.demote_group[0] && !peer->demoted)
866 			session_demote(peer, +1);
867 
868 		/*
869 		 * try to write out what's buffered (maybe a notification),
870 		 * don't bother if it fails
871 		 */
872 		if (peer->state >= STATE_OPENSENT && peer->wbuf.queued)
873 			msgbuf_write(&peer->wbuf);
874 
875 		/*
876 		 * we must start the timer for the next EVNT_START
877 		 * if we are coming here due to an error and the
878 		 * session was not established successfully before, the
879 		 * starttimerinterval needs to be exponentially increased
880 		 */
881 		if (peer->IdleHoldTime == 0)
882 			peer->IdleHoldTime = INTERVAL_IDLE_HOLD_INITIAL;
883 		peer->holdtime = INTERVAL_HOLD_INITIAL;
884 		timer_stop(&peer->timers, Timer_ConnectRetry);
885 		timer_stop(&peer->timers, Timer_Keepalive);
886 		timer_stop(&peer->timers, Timer_Hold);
887 		timer_stop(&peer->timers, Timer_SendHold);
888 		timer_stop(&peer->timers, Timer_IdleHold);
889 		timer_stop(&peer->timers, Timer_IdleHoldReset);
890 		session_close_connection(peer);
891 		msgbuf_clear(&peer->wbuf);
892 		free(peer->rbuf);
893 		peer->rbuf = NULL;
894 		peer->rpending = 0;
895 		bzero(&peer->capa.peer, sizeof(peer->capa.peer));
896 		if (!peer->template)
897 			imsg_compose(ibuf_main, IMSG_PFKEY_RELOAD,
898 			    peer->conf.id, 0, -1, NULL, 0);
899 
900 		if (event != EVNT_STOP) {
901 			timer_set(&peer->timers, Timer_IdleHold,
902 			    peer->IdleHoldTime);
903 			if (event != EVNT_NONE &&
904 			    peer->IdleHoldTime < MAX_IDLE_HOLD/2)
905 				peer->IdleHoldTime *= 2;
906 		}
907 		if (peer->state == STATE_ESTABLISHED) {
908 			if (peer->capa.neg.grestart.restart == 2 &&
909 			    (event == EVNT_CON_CLOSED ||
910 			    event == EVNT_CON_FATAL)) {
911 				/* don't punish graceful restart */
912 				timer_set(&peer->timers, Timer_IdleHold, 0);
913 				peer->IdleHoldTime /= 2;
914 				session_graceful_restart(peer);
915 			} else
916 				session_down(peer);
917 		}
918 		if (peer->state == STATE_NONE ||
919 		    peer->state == STATE_ESTABLISHED) {
920 			/* initialize capability negotiation structures */
921 			memcpy(&peer->capa.ann, &peer->conf.capabilities,
922 			    sizeof(peer->capa.ann));
923 			if (!peer->conf.announce_capa)
924 				session_capa_ann_none(peer);
925 		}
926 		break;
927 	case STATE_CONNECT:
928 		if (peer->state == STATE_ESTABLISHED &&
929 		    peer->capa.neg.grestart.restart == 2) {
930 			/* do the graceful restart dance */
931 			session_graceful_restart(peer);
932 			peer->holdtime = INTERVAL_HOLD_INITIAL;
933 			timer_stop(&peer->timers, Timer_ConnectRetry);
934 			timer_stop(&peer->timers, Timer_Keepalive);
935 			timer_stop(&peer->timers, Timer_Hold);
936 			timer_stop(&peer->timers, Timer_SendHold);
937 			timer_stop(&peer->timers, Timer_IdleHold);
938 			timer_stop(&peer->timers, Timer_IdleHoldReset);
939 			session_close_connection(peer);
940 			msgbuf_clear(&peer->wbuf);
941 			bzero(&peer->capa.peer, sizeof(peer->capa.peer));
942 		}
943 		break;
944 	case STATE_ACTIVE:
945 		if (!peer->template)
946 			imsg_compose(ibuf_main, IMSG_PFKEY_RELOAD,
947 			    peer->conf.id, 0, -1, NULL, 0);
948 		break;
949 	case STATE_OPENSENT:
950 		break;
951 	case STATE_OPENCONFIRM:
952 		break;
953 	case STATE_ESTABLISHED:
954 		timer_set(&peer->timers, Timer_IdleHoldReset,
955 		    peer->IdleHoldTime);
956 		if (peer->demoted)
957 			timer_set(&peer->timers, Timer_CarpUndemote,
958 			    INTERVAL_HOLD_DEMOTED);
959 		session_up(peer);
960 		break;
961 	default:		/* something seriously fucked */
962 		break;
963 	}
964 
965 	log_statechange(peer, state, event);
966 	LIST_FOREACH(mrt, &mrthead, entry) {
967 		if (!(mrt->type == MRT_ALL_IN || mrt->type == MRT_ALL_OUT))
968 			continue;
969 		if ((mrt->peer_id == 0 && mrt->group_id == 0) ||
970 		    mrt->peer_id == peer->conf.id || (mrt->group_id != 0 &&
971 		    mrt->group_id == peer->conf.groupid))
972 			mrt_dump_state(mrt, peer->state, state, peer);
973 	}
974 	peer->prev_state = peer->state;
975 	peer->state = state;
976 }
977 
978 void
979 session_accept(int listenfd)
980 {
981 	int			 connfd;
982 	socklen_t		 len;
983 	struct sockaddr_storage	 cliaddr;
984 	struct peer		*p = NULL;
985 
986 	len = sizeof(cliaddr);
987 	if ((connfd = accept4(listenfd,
988 	    (struct sockaddr *)&cliaddr, &len,
989 	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
990 		if (errno == ENFILE || errno == EMFILE)
991 			pauseaccept = getmonotime();
992 		else if (errno != EWOULDBLOCK && errno != EINTR &&
993 		    errno != ECONNABORTED)
994 			log_warn("accept");
995 		return;
996 	}
997 
998 	p = getpeerbyip(conf, (struct sockaddr *)&cliaddr);
999 
1000 	if (p != NULL && p->state == STATE_IDLE && p->errcnt < 2) {
1001 		if (timer_running(&p->timers, Timer_IdleHold, NULL)) {
1002 			/* fast reconnect after clear */
1003 			p->passive = 1;
1004 			bgp_fsm(p, EVNT_START);
1005 		}
1006 	}
1007 
1008 	if (p != NULL &&
1009 	    (p->state == STATE_CONNECT || p->state == STATE_ACTIVE)) {
1010 		if (p->fd != -1) {
1011 			if (p->state == STATE_CONNECT)
1012 				session_close_connection(p);
1013 			else {
1014 				close(connfd);
1015 				return;
1016 			}
1017 		}
1018 
1019 open:
1020 		if (p->conf.auth.method != AUTH_NONE && sysdep.no_pfkey) {
1021 			log_peer_warnx(&p->conf,
1022 			    "ipsec or md5sig configured but not available");
1023 			close(connfd);
1024 			return;
1025 		}
1026 
1027 		if (tcp_md5_check(connfd, p) == -1) {
1028 			close(connfd);
1029 			return;
1030 		}
1031 		p->fd = p->wbuf.fd = connfd;
1032 		if (session_setup_socket(p)) {
1033 			close(connfd);
1034 			return;
1035 		}
1036 		bgp_fsm(p, EVNT_CON_OPEN);
1037 		return;
1038 	} else if (p != NULL && p->state == STATE_ESTABLISHED &&
1039 	    p->capa.neg.grestart.restart == 2) {
1040 		/* first do the graceful restart dance */
1041 		change_state(p, STATE_CONNECT, EVNT_CON_CLOSED);
1042 		/* then do part of the open dance */
1043 		goto open;
1044 	} else {
1045 		log_conn_attempt(p, (struct sockaddr *)&cliaddr, len);
1046 		close(connfd);
1047 	}
1048 }
1049 
1050 int
1051 session_connect(struct peer *peer)
1052 {
1053 	struct sockaddr		*sa;
1054 	struct bgpd_addr	*bind_addr = NULL;
1055 	socklen_t		 sa_len;
1056 
1057 	/*
1058 	 * we do not need the overcomplicated collision detection RFC 1771
1059 	 * describes; we simply make sure there is only ever one concurrent
1060 	 * tcp connection per peer.
1061 	 */
1062 	if (peer->fd != -1)
1063 		return (-1);
1064 
1065 	if ((peer->fd = socket(aid2af(peer->conf.remote_addr.aid),
1066 	    SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_TCP)) == -1) {
1067 		log_peer_warn(&peer->conf, "session_connect socket");
1068 		bgp_fsm(peer, EVNT_CON_OPENFAIL);
1069 		return (-1);
1070 	}
1071 
1072 	if (peer->conf.auth.method != AUTH_NONE && sysdep.no_pfkey) {
1073 		log_peer_warnx(&peer->conf,
1074 		    "ipsec or md5sig configured but not available");
1075 		bgp_fsm(peer, EVNT_CON_OPENFAIL);
1076 		return (-1);
1077 	}
1078 
1079 	tcp_md5_set(peer->fd, peer);
1080 	peer->wbuf.fd = peer->fd;
1081 
1082 	/* if local-address is set we need to bind() */
1083 	switch (peer->conf.remote_addr.aid) {
1084 	case AID_INET:
1085 		bind_addr = &peer->conf.local_addr_v4;
1086 		break;
1087 	case AID_INET6:
1088 		bind_addr = &peer->conf.local_addr_v6;
1089 		break;
1090 	}
1091 	if ((sa = addr2sa(bind_addr, 0, &sa_len)) != NULL) {
1092 		if (bind(peer->fd, sa, sa_len) == -1) {
1093 			log_peer_warn(&peer->conf, "session_connect bind");
1094 			bgp_fsm(peer, EVNT_CON_OPENFAIL);
1095 			return (-1);
1096 		}
1097 	}
1098 
1099 	if (session_setup_socket(peer)) {
1100 		bgp_fsm(peer, EVNT_CON_OPENFAIL);
1101 		return (-1);
1102 	}
1103 
1104 	sa = addr2sa(&peer->conf.remote_addr, peer->conf.remote_port, &sa_len);
1105 	if (connect(peer->fd, sa, sa_len) == -1) {
1106 		if (errno != EINPROGRESS) {
1107 			if (errno != peer->lasterr)
1108 				log_peer_warn(&peer->conf, "connect");
1109 			peer->lasterr = errno;
1110 			bgp_fsm(peer, EVNT_CON_OPENFAIL);
1111 			return (-1);
1112 		}
1113 	} else
1114 		bgp_fsm(peer, EVNT_CON_OPEN);
1115 
1116 	return (0);
1117 }
1118 
1119 int
1120 session_setup_socket(struct peer *p)
1121 {
1122 	int	ttl = p->conf.distance;
1123 	int	pre = IPTOS_PREC_INTERNETCONTROL;
1124 	int	nodelay = 1;
1125 	int	bsize;
1126 
1127 	switch (p->conf.remote_addr.aid) {
1128 	case AID_INET:
1129 		/* set precedence, see RFC 1771 appendix 5 */
1130 		if (setsockopt(p->fd, IPPROTO_IP, IP_TOS, &pre, sizeof(pre)) ==
1131 		    -1) {
1132 			log_peer_warn(&p->conf,
1133 			    "session_setup_socket setsockopt TOS");
1134 			return (-1);
1135 		}
1136 
1137 		if (p->conf.ebgp) {
1138 			/*
1139 			 * set TTL to foreign router's distance
1140 			 * 1=direct n=multihop with ttlsec, we always use 255
1141 			 */
1142 			if (p->conf.ttlsec) {
1143 				ttl = 256 - p->conf.distance;
1144 				if (setsockopt(p->fd, IPPROTO_IP, IP_MINTTL,
1145 				    &ttl, sizeof(ttl)) == -1) {
1146 					log_peer_warn(&p->conf,
1147 					    "session_setup_socket: "
1148 					    "setsockopt MINTTL");
1149 					return (-1);
1150 				}
1151 				ttl = 255;
1152 			}
1153 
1154 			if (setsockopt(p->fd, IPPROTO_IP, IP_TTL, &ttl,
1155 			    sizeof(ttl)) == -1) {
1156 				log_peer_warn(&p->conf,
1157 				    "session_setup_socket setsockopt TTL");
1158 				return (-1);
1159 			}
1160 		}
1161 		break;
1162 	case AID_INET6:
1163 		if (p->conf.ebgp) {
1164 			/*
1165 			 * set hoplimit to foreign router's distance
1166 			 * 1=direct n=multihop with ttlsec, we always use 255
1167 			 */
1168 			if (p->conf.ttlsec) {
1169 				ttl = 256 - p->conf.distance;
1170 				if (setsockopt(p->fd, IPPROTO_IPV6,
1171 				    IPV6_MINHOPCOUNT, &ttl, sizeof(ttl))
1172 				    == -1) {
1173 					log_peer_warn(&p->conf,
1174 					    "session_setup_socket: "
1175 					    "setsockopt MINHOPCOUNT");
1176 					return (-1);
1177 				}
1178 				ttl = 255;
1179 			}
1180 			if (setsockopt(p->fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS,
1181 			    &ttl, sizeof(ttl)) == -1) {
1182 				log_peer_warn(&p->conf,
1183 				    "session_setup_socket setsockopt hoplimit");
1184 				return (-1);
1185 			}
1186 		}
1187 		break;
1188 	}
1189 
1190 	/* set TCP_NODELAY */
1191 	if (setsockopt(p->fd, IPPROTO_TCP, TCP_NODELAY, &nodelay,
1192 	    sizeof(nodelay)) == -1) {
1193 		log_peer_warn(&p->conf,
1194 		    "session_setup_socket setsockopt TCP_NODELAY");
1195 		return (-1);
1196 	}
1197 
1198 	/* only increase bufsize (and thus window) if md5 or ipsec is in use */
1199 	if (p->conf.auth.method != AUTH_NONE) {
1200 		/* try to increase bufsize. no biggie if it fails */
1201 		bsize = 65535;
1202 		while (bsize > 8192 &&
1203 		    setsockopt(p->fd, SOL_SOCKET, SO_RCVBUF, &bsize,
1204 		    sizeof(bsize)) == -1 && errno != EINVAL)
1205 			bsize /= 2;
1206 		bsize = 65535;
1207 		while (bsize > 8192 &&
1208 		    setsockopt(p->fd, SOL_SOCKET, SO_SNDBUF, &bsize,
1209 		    sizeof(bsize)) == -1 && errno != EINVAL)
1210 			bsize /= 2;
1211 	}
1212 
1213 	return (0);
1214 }
1215 
1216 /* compare two sockaddrs by converting them into bgpd_addr */
1217 static int
1218 sa_cmp(struct sockaddr *a, struct sockaddr *b)
1219 {
1220 	struct bgpd_addr ba, bb;
1221 
1222 	sa2addr(a, &ba, NULL);
1223 	sa2addr(b, &bb, NULL);
1224 
1225 	return (memcmp(&ba, &bb, sizeof(ba)) == 0);
1226 }
1227 
1228 static void
1229 get_alternate_addr(struct sockaddr *sa, struct bgpd_addr *alt)
1230 {
1231 	struct ifaddrs	*ifap, *ifa, *match;
1232 
1233 	if (getifaddrs(&ifap) == -1)
1234 		fatal("getifaddrs");
1235 
1236 	for (match = ifap; match != NULL; match = match->ifa_next)
1237 		if (match->ifa_addr != NULL &&
1238 		    sa_cmp(sa, match->ifa_addr) == 0)
1239 			break;
1240 
1241 	if (match == NULL) {
1242 		log_warnx("%s: local address not found", __func__);
1243 		return;
1244 	}
1245 
1246 	switch (sa->sa_family) {
1247 	case AF_INET6:
1248 		for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
1249 			if (ifa->ifa_addr != NULL &&
1250 			    ifa->ifa_addr->sa_family == AF_INET &&
1251 			    strcmp(ifa->ifa_name, match->ifa_name) == 0) {
1252 				sa2addr(ifa->ifa_addr, alt, NULL);
1253 				break;
1254 			}
1255 		}
1256 		break;
1257 	case AF_INET:
1258 		for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
1259 			if (ifa->ifa_addr != NULL &&
1260 			    ifa->ifa_addr->sa_family == AF_INET6 &&
1261 			    strcmp(ifa->ifa_name, match->ifa_name) == 0) {
1262 				struct sockaddr_in6 *s =
1263 				    (struct sockaddr_in6 *)ifa->ifa_addr;
1264 
1265 				/* only accept global scope addresses */
1266 				if (IN6_IS_ADDR_LINKLOCAL(&s->sin6_addr) ||
1267 				    IN6_IS_ADDR_SITELOCAL(&s->sin6_addr))
1268 					continue;
1269 				sa2addr(ifa->ifa_addr, alt, NULL);
1270 				break;
1271 			}
1272 		}
1273 		break;
1274 	default:
1275 		log_warnx("%s: unsupported address family %d", __func__,
1276 		    sa->sa_family);
1277 		break;
1278 	}
1279 
1280 	freeifaddrs(ifap);
1281 }
1282 
1283 void
1284 session_tcp_established(struct peer *peer)
1285 {
1286 	struct sockaddr_storage	ss;
1287 	socklen_t		len;
1288 
1289 	len = sizeof(ss);
1290 	if (getsockname(peer->fd, (struct sockaddr *)&ss, &len) == -1)
1291 		log_warn("getsockname");
1292 	sa2addr((struct sockaddr *)&ss, &peer->local, &peer->local_port);
1293 	get_alternate_addr((struct sockaddr *)&ss, &peer->local_alt);
1294 	len = sizeof(ss);
1295 	if (getpeername(peer->fd, (struct sockaddr *)&ss, &len) == -1)
1296 		log_warn("getpeername");
1297 	sa2addr((struct sockaddr *)&ss, &peer->remote, &peer->remote_port);
1298 }
1299 
1300 void
1301 session_capa_ann_none(struct peer *peer)
1302 {
1303 	bzero(&peer->capa.ann, sizeof(peer->capa.ann));
1304 }
1305 
1306 int
1307 session_capa_add(struct ibuf *opb, uint8_t capa_code, uint8_t capa_len)
1308 {
1309 	int errs = 0;
1310 
1311 	errs += ibuf_add(opb, &capa_code, sizeof(capa_code));
1312 	errs += ibuf_add(opb, &capa_len, sizeof(capa_len));
1313 	return (errs);
1314 }
1315 
1316 int
1317 session_capa_add_mp(struct ibuf *buf, uint8_t aid)
1318 {
1319 	uint8_t			 safi, pad = 0;
1320 	uint16_t		 afi;
1321 	int			 errs = 0;
1322 
1323 	if (aid2afi(aid, &afi, &safi) == -1)
1324 		fatalx("session_capa_add_mp: bad afi/safi pair");
1325 	afi = htons(afi);
1326 	errs += ibuf_add(buf, &afi, sizeof(afi));
1327 	errs += ibuf_add(buf, &pad, sizeof(pad));
1328 	errs += ibuf_add(buf, &safi, sizeof(safi));
1329 
1330 	return (errs);
1331 }
1332 
1333 int
1334 session_capa_add_afi(struct peer *p, struct ibuf *b, uint8_t aid,
1335     uint8_t flags)
1336 {
1337 	u_int		errs = 0;
1338 	uint16_t	afi;
1339 	uint8_t		safi;
1340 
1341 	if (aid2afi(aid, &afi, &safi)) {
1342 		log_warn("session_capa_add_afi: bad AID");
1343 		return (1);
1344 	}
1345 
1346 	afi = htons(afi);
1347 	errs += ibuf_add(b, &afi, sizeof(afi));
1348 	errs += ibuf_add(b, &safi, sizeof(safi));
1349 	errs += ibuf_add(b, &flags, sizeof(flags));
1350 
1351 	return (errs);
1352 }
1353 
1354 struct bgp_msg *
1355 session_newmsg(enum msg_type msgtype, uint16_t len)
1356 {
1357 	struct bgp_msg		*msg;
1358 	struct msg_header	 hdr;
1359 	struct ibuf		*buf;
1360 	int			 errs = 0;
1361 
1362 	memset(&hdr.marker, 0xff, sizeof(hdr.marker));
1363 	hdr.len = htons(len);
1364 	hdr.type = msgtype;
1365 
1366 	if ((buf = ibuf_open(len)) == NULL)
1367 		return (NULL);
1368 
1369 	errs += ibuf_add(buf, &hdr.marker, sizeof(hdr.marker));
1370 	errs += ibuf_add(buf, &hdr.len, sizeof(hdr.len));
1371 	errs += ibuf_add(buf, &hdr.type, sizeof(hdr.type));
1372 
1373 	if (errs || (msg = calloc(1, sizeof(*msg))) == NULL) {
1374 		ibuf_free(buf);
1375 		return (NULL);
1376 	}
1377 
1378 	msg->buf = buf;
1379 	msg->type = msgtype;
1380 	msg->len = len;
1381 
1382 	return (msg);
1383 }
1384 
1385 int
1386 session_sendmsg(struct bgp_msg *msg, struct peer *p)
1387 {
1388 	struct mrt		*mrt;
1389 
1390 	LIST_FOREACH(mrt, &mrthead, entry) {
1391 		if (!(mrt->type == MRT_ALL_OUT || (msg->type == UPDATE &&
1392 		    mrt->type == MRT_UPDATE_OUT)))
1393 			continue;
1394 		if ((mrt->peer_id == 0 && mrt->group_id == 0) ||
1395 		    mrt->peer_id == p->conf.id || (mrt->group_id != 0 &&
1396 		    mrt->group_id == p->conf.groupid))
1397 			mrt_dump_bgp_msg(mrt, msg->buf->buf, msg->len, p,
1398 			    msg->type);
1399 	}
1400 
1401 	ibuf_close(&p->wbuf, msg->buf);
1402 	if (!p->throttled && p->wbuf.queued > SESS_MSG_HIGH_MARK) {
1403 		if (imsg_rde(IMSG_XOFF, p->conf.id, NULL, 0) == -1)
1404 			log_peer_warn(&p->conf, "imsg_compose XOFF");
1405 		else
1406 			p->throttled = 1;
1407 	}
1408 
1409 	free(msg);
1410 	return (0);
1411 }
1412 
1413 void
1414 session_open(struct peer *p)
1415 {
1416 	struct bgp_msg		*buf;
1417 	struct ibuf		*opb;
1418 	struct msg_open		 msg;
1419 	uint16_t		 len, optparamlen = 0;
1420 	uint8_t			 i, op_type;
1421 	int			 errs = 0, extlen = 0;
1422 	int			 mpcapa = 0;
1423 
1424 
1425 	if ((opb = ibuf_dynamic(0, UINT16_MAX - 3)) == NULL) {
1426 		bgp_fsm(p, EVNT_CON_FATAL);
1427 		return;
1428 	}
1429 
1430 	/* multiprotocol extensions, RFC 4760 */
1431 	for (i = 0; i < AID_MAX; i++)
1432 		if (p->capa.ann.mp[i]) {	/* 4 bytes data */
1433 			errs += session_capa_add(opb, CAPA_MP, 4);
1434 			errs += session_capa_add_mp(opb, i);
1435 			mpcapa++;
1436 		}
1437 
1438 	/* route refresh, RFC 2918 */
1439 	if (p->capa.ann.refresh)	/* no data */
1440 		errs += session_capa_add(opb, CAPA_REFRESH, 0);
1441 
1442 	/* graceful restart and End-of-RIB marker, RFC 4724 */
1443 	if (p->capa.ann.grestart.restart) {
1444 		int		rst = 0;
1445 		uint16_t	hdr = 0;
1446 
1447 		for (i = 0; i < AID_MAX; i++) {
1448 			if (p->capa.neg.grestart.flags[i] & CAPA_GR_RESTARTING)
1449 				rst++;
1450 		}
1451 
1452 		/* Only set the R-flag if no graceful restart is ongoing */
1453 		if (!rst)
1454 			hdr |= CAPA_GR_R_FLAG;
1455 		hdr = htons(hdr);
1456 
1457 		errs += session_capa_add(opb, CAPA_RESTART, sizeof(hdr));
1458 		errs += ibuf_add(opb, &hdr, sizeof(hdr));
1459 	}
1460 
1461 	/* 4-bytes AS numbers, RFC6793 */
1462 	if (p->capa.ann.as4byte) {	/* 4 bytes data */
1463 		uint32_t	nas;
1464 
1465 		nas = htonl(p->conf.local_as);
1466 		errs += session_capa_add(opb, CAPA_AS4BYTE, sizeof(nas));
1467 		errs += ibuf_add(opb, &nas, sizeof(nas));
1468 	}
1469 
1470 	/* advertisement of multiple paths, RFC7911 */
1471 	if (p->capa.ann.add_path[0]) {	/* variable */
1472 		uint8_t	aplen;
1473 
1474 		if (mpcapa)
1475 			aplen = 4 * mpcapa;
1476 		else	/* AID_INET */
1477 			aplen = 4;
1478 		errs += session_capa_add(opb, CAPA_ADD_PATH, aplen);
1479 		if (mpcapa) {
1480 			for (i = AID_MIN; i < AID_MAX; i++) {
1481 				if (p->capa.ann.mp[i]) {
1482 					errs += session_capa_add_afi(p, opb,
1483 					    i, p->capa.ann.add_path[i]);
1484 				}
1485 			}
1486 		} else {	/* AID_INET */
1487 			errs += session_capa_add_afi(p, opb, AID_INET,
1488 			    p->capa.ann.add_path[AID_INET]);
1489 		}
1490 	}
1491 
1492 	/* enhanced route-refresh, RFC7313 */
1493 	if (p->capa.ann.enhanced_rr)	/* no data */
1494 		errs += session_capa_add(opb, CAPA_ENHANCED_RR, 0);
1495 
1496 	optparamlen = ibuf_size(opb);
1497 	if (optparamlen == 0) {
1498 		/* nothing */
1499 	} else if (optparamlen + 2 >= 255) {
1500 		/* RFC9072: 2 byte lenght instead of 1 + 3 byte extra header */
1501 		optparamlen += sizeof(op_type) + 2 + 3;
1502 		msg.optparamlen = 255;
1503 		extlen = 1;
1504 	} else {
1505 		optparamlen += sizeof(op_type) + 1;
1506 		msg.optparamlen = optparamlen;
1507 	}
1508 
1509 	len = MSGSIZE_OPEN_MIN + optparamlen;
1510 	if (errs || (buf = session_newmsg(OPEN, len)) == NULL) {
1511 		ibuf_free(opb);
1512 		bgp_fsm(p, EVNT_CON_FATAL);
1513 		return;
1514 	}
1515 
1516 	msg.version = 4;
1517 	msg.myas = htons(p->conf.local_short_as);
1518 	if (p->conf.holdtime)
1519 		msg.holdtime = htons(p->conf.holdtime);
1520 	else
1521 		msg.holdtime = htons(conf->holdtime);
1522 	msg.bgpid = conf->bgpid;	/* is already in network byte order */
1523 
1524 	errs += ibuf_add(buf->buf, &msg.version, sizeof(msg.version));
1525 	errs += ibuf_add(buf->buf, &msg.myas, sizeof(msg.myas));
1526 	errs += ibuf_add(buf->buf, &msg.holdtime, sizeof(msg.holdtime));
1527 	errs += ibuf_add(buf->buf, &msg.bgpid, sizeof(msg.bgpid));
1528 	errs += ibuf_add(buf->buf, &msg.optparamlen, 1);
1529 
1530 	if (extlen) {
1531 		/* write RFC9072 extra header */
1532 		uint16_t op_extlen = htons(optparamlen - 3);
1533 		op_type = OPT_PARAM_EXT_LEN;
1534 		errs += ibuf_add(buf->buf, &op_type, 1);
1535 		errs += ibuf_add(buf->buf, &op_extlen, 2);
1536 	}
1537 
1538 	if (optparamlen) {
1539 		op_type = OPT_PARAM_CAPABILITIES;
1540 		errs += ibuf_add(buf->buf, &op_type, sizeof(op_type));
1541 
1542 		optparamlen = ibuf_size(opb);
1543 		if (extlen) {
1544 			/* RFC9072: 2-byte extended length */
1545 			uint16_t op_extlen = htons(optparamlen);
1546 			errs += ibuf_add(buf->buf, &op_extlen, 2);
1547 		} else {
1548 			uint8_t op_len = optparamlen;
1549 			errs += ibuf_add(buf->buf, &op_len, 1);
1550 		}
1551 		errs += ibuf_add(buf->buf, opb->buf, ibuf_size(opb));
1552 	}
1553 
1554 	ibuf_free(opb);
1555 
1556 	if (errs) {
1557 		ibuf_free(buf->buf);
1558 		free(buf);
1559 		bgp_fsm(p, EVNT_CON_FATAL);
1560 		return;
1561 	}
1562 
1563 	if (session_sendmsg(buf, p) == -1) {
1564 		bgp_fsm(p, EVNT_CON_FATAL);
1565 		return;
1566 	}
1567 
1568 	p->stats.msg_sent_open++;
1569 }
1570 
1571 void
1572 session_keepalive(struct peer *p)
1573 {
1574 	struct bgp_msg		*buf;
1575 
1576 	if ((buf = session_newmsg(KEEPALIVE, MSGSIZE_KEEPALIVE)) == NULL ||
1577 	    session_sendmsg(buf, p) == -1) {
1578 		bgp_fsm(p, EVNT_CON_FATAL);
1579 		return;
1580 	}
1581 
1582 	start_timer_keepalive(p);
1583 	p->stats.msg_sent_keepalive++;
1584 }
1585 
1586 void
1587 session_update(uint32_t peerid, void *data, size_t datalen)
1588 {
1589 	struct peer		*p;
1590 	struct bgp_msg		*buf;
1591 
1592 	if ((p = getpeerbyid(conf, peerid)) == NULL) {
1593 		log_warnx("no such peer: id=%u", peerid);
1594 		return;
1595 	}
1596 
1597 	if (p->state != STATE_ESTABLISHED)
1598 		return;
1599 
1600 	if ((buf = session_newmsg(UPDATE, MSGSIZE_HEADER + datalen)) == NULL) {
1601 		bgp_fsm(p, EVNT_CON_FATAL);
1602 		return;
1603 	}
1604 
1605 	if (ibuf_add(buf->buf, data, datalen)) {
1606 		ibuf_free(buf->buf);
1607 		free(buf);
1608 		bgp_fsm(p, EVNT_CON_FATAL);
1609 		return;
1610 	}
1611 
1612 	if (session_sendmsg(buf, p) == -1) {
1613 		bgp_fsm(p, EVNT_CON_FATAL);
1614 		return;
1615 	}
1616 
1617 	start_timer_keepalive(p);
1618 	p->stats.msg_sent_update++;
1619 }
1620 
1621 void
1622 session_notification(struct peer *p, uint8_t errcode, uint8_t subcode,
1623     void *data, ssize_t datalen)
1624 {
1625 	struct bgp_msg		*buf;
1626 	int			 errs = 0;
1627 
1628 	if (p->stats.last_sent_errcode)	/* some notification already sent */
1629 		return;
1630 
1631 	log_notification(p, errcode, subcode, data, datalen, "sending");
1632 
1633 	/* cap to maximum size */
1634 	if (datalen > MAX_PKTSIZE - MSGSIZE_NOTIFICATION_MIN) {
1635 		log_peer_warnx(&p->conf,
1636 		    "oversized notification, data trunkated");
1637 		datalen = MAX_PKTSIZE - MSGSIZE_NOTIFICATION_MIN;
1638 	}
1639 
1640 	if ((buf = session_newmsg(NOTIFICATION,
1641 	    MSGSIZE_NOTIFICATION_MIN + datalen)) == NULL) {
1642 		bgp_fsm(p, EVNT_CON_FATAL);
1643 		return;
1644 	}
1645 
1646 	errs += ibuf_add(buf->buf, &errcode, sizeof(errcode));
1647 	errs += ibuf_add(buf->buf, &subcode, sizeof(subcode));
1648 
1649 	if (datalen > 0)
1650 		errs += ibuf_add(buf->buf, data, datalen);
1651 
1652 	if (errs) {
1653 		ibuf_free(buf->buf);
1654 		free(buf);
1655 		bgp_fsm(p, EVNT_CON_FATAL);
1656 		return;
1657 	}
1658 
1659 	if (session_sendmsg(buf, p) == -1) {
1660 		bgp_fsm(p, EVNT_CON_FATAL);
1661 		return;
1662 	}
1663 
1664 	p->stats.msg_sent_notification++;
1665 	p->stats.last_sent_errcode = errcode;
1666 	p->stats.last_sent_suberr = subcode;
1667 }
1668 
1669 int
1670 session_neighbor_rrefresh(struct peer *p)
1671 {
1672 	uint8_t	i;
1673 
1674 	if (!(p->capa.neg.refresh || p->capa.neg.enhanced_rr))
1675 		return (-1);
1676 
1677 	for (i = 0; i < AID_MAX; i++) {
1678 		if (p->capa.neg.mp[i] != 0)
1679 			session_rrefresh(p, i, ROUTE_REFRESH_REQUEST);
1680 	}
1681 
1682 	return (0);
1683 }
1684 
1685 void
1686 session_rrefresh(struct peer *p, uint8_t aid, uint8_t subtype)
1687 {
1688 	struct bgp_msg		*buf;
1689 	int			 errs = 0;
1690 	uint16_t		 afi;
1691 	uint8_t			 safi;
1692 
1693 	switch (subtype) {
1694 	case ROUTE_REFRESH_REQUEST:
1695 		p->stats.refresh_sent_req++;
1696 		break;
1697 	case ROUTE_REFRESH_BEGIN_RR:
1698 	case ROUTE_REFRESH_END_RR:
1699 		/* requires enhanced route refresh */
1700 		if (!p->capa.neg.enhanced_rr)
1701 			return;
1702 		if (subtype == ROUTE_REFRESH_BEGIN_RR)
1703 			p->stats.refresh_sent_borr++;
1704 		else
1705 			p->stats.refresh_sent_eorr++;
1706 		break;
1707 	default:
1708 		fatalx("session_rrefresh: bad subtype %d", subtype);
1709 	}
1710 
1711 	if (aid2afi(aid, &afi, &safi) == -1)
1712 		fatalx("session_rrefresh: bad afi/safi pair");
1713 
1714 	if ((buf = session_newmsg(RREFRESH, MSGSIZE_RREFRESH)) == NULL) {
1715 		bgp_fsm(p, EVNT_CON_FATAL);
1716 		return;
1717 	}
1718 
1719 	afi = htons(afi);
1720 	errs += ibuf_add(buf->buf, &afi, sizeof(afi));
1721 	errs += ibuf_add(buf->buf, &subtype, sizeof(subtype));
1722 	errs += ibuf_add(buf->buf, &safi, sizeof(safi));
1723 
1724 	if (errs) {
1725 		ibuf_free(buf->buf);
1726 		free(buf);
1727 		bgp_fsm(p, EVNT_CON_FATAL);
1728 		return;
1729 	}
1730 
1731 	if (session_sendmsg(buf, p) == -1) {
1732 		bgp_fsm(p, EVNT_CON_FATAL);
1733 		return;
1734 	}
1735 
1736 	p->stats.msg_sent_rrefresh++;
1737 }
1738 
1739 int
1740 session_graceful_restart(struct peer *p)
1741 {
1742 	uint8_t	i;
1743 
1744 	timer_set(&p->timers, Timer_RestartTimeout,
1745 	    p->capa.neg.grestart.timeout);
1746 
1747 	for (i = 0; i < AID_MAX; i++) {
1748 		if (p->capa.neg.grestart.flags[i] & CAPA_GR_PRESENT) {
1749 			if (imsg_rde(IMSG_SESSION_STALE, p->conf.id,
1750 			    &i, sizeof(i)) == -1)
1751 				return (-1);
1752 			log_peer_warnx(&p->conf,
1753 			    "graceful restart of %s, keeping routes",
1754 			    aid2str(i));
1755 			p->capa.neg.grestart.flags[i] |= CAPA_GR_RESTARTING;
1756 		} else if (p->capa.neg.mp[i]) {
1757 			if (imsg_rde(IMSG_SESSION_FLUSH, p->conf.id,
1758 			    &i, sizeof(i)) == -1)
1759 				return (-1);
1760 			log_peer_warnx(&p->conf,
1761 			    "graceful restart of %s, flushing routes",
1762 			    aid2str(i));
1763 		}
1764 	}
1765 	return (0);
1766 }
1767 
1768 int
1769 session_graceful_stop(struct peer *p)
1770 {
1771 	uint8_t	i;
1772 
1773 	for (i = 0; i < AID_MAX; i++) {
1774 		/*
1775 		 * Only flush if the peer is restarting and the timeout fired.
1776 		 * In all other cases the session was already flushed when the
1777 		 * session went down or when the new open message was parsed.
1778 		 */
1779 		if (p->capa.neg.grestart.flags[i] & CAPA_GR_RESTARTING) {
1780 			log_peer_warnx(&p->conf, "graceful restart of %s, "
1781 			    "time-out, flushing", aid2str(i));
1782 			if (imsg_rde(IMSG_SESSION_FLUSH, p->conf.id,
1783 			    &i, sizeof(i)) == -1)
1784 				return (-1);
1785 		}
1786 		p->capa.neg.grestart.flags[i] &= ~CAPA_GR_RESTARTING;
1787 	}
1788 	return (0);
1789 }
1790 
1791 int
1792 session_dispatch_msg(struct pollfd *pfd, struct peer *p)
1793 {
1794 	ssize_t		n;
1795 	socklen_t	len;
1796 	int		error;
1797 
1798 	if (p->state == STATE_CONNECT) {
1799 		if (pfd->revents & POLLOUT) {
1800 			if (pfd->revents & POLLIN) {
1801 				/* error occurred */
1802 				len = sizeof(error);
1803 				if (getsockopt(pfd->fd, SOL_SOCKET, SO_ERROR,
1804 				    &error, &len) == -1 || error) {
1805 					if (error)
1806 						errno = error;
1807 					if (errno != p->lasterr) {
1808 						log_peer_warn(&p->conf,
1809 						    "socket error");
1810 						p->lasterr = errno;
1811 					}
1812 					bgp_fsm(p, EVNT_CON_OPENFAIL);
1813 					return (1);
1814 				}
1815 			}
1816 			bgp_fsm(p, EVNT_CON_OPEN);
1817 			return (1);
1818 		}
1819 		if (pfd->revents & POLLHUP) {
1820 			bgp_fsm(p, EVNT_CON_OPENFAIL);
1821 			return (1);
1822 		}
1823 		if (pfd->revents & (POLLERR|POLLNVAL)) {
1824 			bgp_fsm(p, EVNT_CON_FATAL);
1825 			return (1);
1826 		}
1827 		return (0);
1828 	}
1829 
1830 	if (pfd->revents & POLLHUP) {
1831 		bgp_fsm(p, EVNT_CON_CLOSED);
1832 		return (1);
1833 	}
1834 	if (pfd->revents & (POLLERR|POLLNVAL)) {
1835 		bgp_fsm(p, EVNT_CON_FATAL);
1836 		return (1);
1837 	}
1838 
1839 	if (pfd->revents & POLLOUT && p->wbuf.queued) {
1840 		if ((error = msgbuf_write(&p->wbuf)) <= 0 && errno != EAGAIN) {
1841 			if (error == 0)
1842 				log_peer_warnx(&p->conf, "Connection closed");
1843 			else if (error == -1)
1844 				log_peer_warn(&p->conf, "write error");
1845 			bgp_fsm(p, EVNT_CON_FATAL);
1846 			return (1);
1847 		}
1848 		p->stats.last_write = getmonotime();
1849 		if (p->holdtime > 0)
1850 			timer_set(&p->timers, Timer_SendHold,
1851 			    p->holdtime < INTERVAL_HOLD ? INTERVAL_HOLD :
1852 			    p->holdtime);
1853 		if (p->throttled && p->wbuf.queued < SESS_MSG_LOW_MARK) {
1854 			if (imsg_rde(IMSG_XON, p->conf.id, NULL, 0) == -1)
1855 				log_peer_warn(&p->conf, "imsg_compose XON");
1856 			else
1857 				p->throttled = 0;
1858 		}
1859 		if (!(pfd->revents & POLLIN))
1860 			return (1);
1861 	}
1862 
1863 	if (p->rbuf && pfd->revents & POLLIN) {
1864 		if ((n = read(p->fd, p->rbuf->buf + p->rbuf->wpos,
1865 		    sizeof(p->rbuf->buf) - p->rbuf->wpos)) == -1) {
1866 			if (errno != EINTR && errno != EAGAIN) {
1867 				log_peer_warn(&p->conf, "read error");
1868 				bgp_fsm(p, EVNT_CON_FATAL);
1869 			}
1870 			return (1);
1871 		}
1872 		if (n == 0) {	/* connection closed */
1873 			bgp_fsm(p, EVNT_CON_CLOSED);
1874 			return (1);
1875 		}
1876 
1877 		p->rbuf->wpos += n;
1878 		p->stats.last_read = getmonotime();
1879 		return (1);
1880 	}
1881 	return (0);
1882 }
1883 
1884 void
1885 session_process_msg(struct peer *p)
1886 {
1887 	struct mrt	*mrt;
1888 	ssize_t		rpos, av, left;
1889 	int		processed = 0;
1890 	uint16_t	msglen;
1891 	uint8_t		msgtype;
1892 
1893 	rpos = 0;
1894 	av = p->rbuf->wpos;
1895 	p->rpending = 0;
1896 
1897 	/*
1898 	 * session might drop to IDLE -> buffers deallocated
1899 	 * we MUST check rbuf != NULL before use
1900 	 */
1901 	for (;;) {
1902 		if (p->rbuf == NULL)
1903 			return;
1904 		if (rpos + MSGSIZE_HEADER > av)
1905 			break;
1906 		if (parse_header(p, p->rbuf->buf + rpos, &msglen,
1907 		    &msgtype) == -1)
1908 			return;
1909 		if (rpos + msglen > av)
1910 			break;
1911 		p->rbuf->rptr = p->rbuf->buf + rpos;
1912 
1913 		/* dump to MRT as soon as we have a full packet */
1914 		LIST_FOREACH(mrt, &mrthead, entry) {
1915 			if (!(mrt->type == MRT_ALL_IN || (msgtype == UPDATE &&
1916 			    mrt->type == MRT_UPDATE_IN)))
1917 				continue;
1918 			if ((mrt->peer_id == 0 && mrt->group_id == 0) ||
1919 			    mrt->peer_id == p->conf.id || (mrt->group_id != 0 &&
1920 			    mrt->group_id == p->conf.groupid))
1921 				mrt_dump_bgp_msg(mrt, p->rbuf->rptr, msglen, p,
1922 				    msgtype);
1923 		}
1924 
1925 		switch (msgtype) {
1926 		case OPEN:
1927 			bgp_fsm(p, EVNT_RCVD_OPEN);
1928 			p->stats.msg_rcvd_open++;
1929 			break;
1930 		case UPDATE:
1931 			bgp_fsm(p, EVNT_RCVD_UPDATE);
1932 			p->stats.msg_rcvd_update++;
1933 			break;
1934 		case NOTIFICATION:
1935 			bgp_fsm(p, EVNT_RCVD_NOTIFICATION);
1936 			p->stats.msg_rcvd_notification++;
1937 			break;
1938 		case KEEPALIVE:
1939 			bgp_fsm(p, EVNT_RCVD_KEEPALIVE);
1940 			p->stats.msg_rcvd_keepalive++;
1941 			break;
1942 		case RREFRESH:
1943 			parse_rrefresh(p);
1944 			p->stats.msg_rcvd_rrefresh++;
1945 			break;
1946 		default:	/* cannot happen */
1947 			session_notification(p, ERR_HEADER, ERR_HDR_TYPE,
1948 			    &msgtype, 1);
1949 			log_warnx("received message with unknown type %u",
1950 			    msgtype);
1951 			bgp_fsm(p, EVNT_CON_FATAL);
1952 		}
1953 		rpos += msglen;
1954 		if (++processed > MSG_PROCESS_LIMIT) {
1955 			p->rpending = 1;
1956 			break;
1957 		}
1958 	}
1959 
1960 	if (rpos < av) {
1961 		left = av - rpos;
1962 		memmove(&p->rbuf->buf, p->rbuf->buf + rpos, left);
1963 		p->rbuf->wpos = left;
1964 	} else
1965 		p->rbuf->wpos = 0;
1966 }
1967 
1968 int
1969 parse_header(struct peer *peer, u_char *data, uint16_t *len, uint8_t *type)
1970 {
1971 	u_char			*p;
1972 	uint16_t		 olen;
1973 	static const uint8_t	 marker[MSGSIZE_HEADER_MARKER] = { 0xff, 0xff,
1974 				    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
1975 				    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
1976 
1977 	/* caller MUST make sure we are getting 19 bytes! */
1978 	p = data;
1979 	if (memcmp(p, marker, sizeof(marker))) {
1980 		log_peer_warnx(&peer->conf, "sync error");
1981 		session_notification(peer, ERR_HEADER, ERR_HDR_SYNC, NULL, 0);
1982 		bgp_fsm(peer, EVNT_CON_FATAL);
1983 		return (-1);
1984 	}
1985 	p += MSGSIZE_HEADER_MARKER;
1986 
1987 	memcpy(&olen, p, 2);
1988 	*len = ntohs(olen);
1989 	p += 2;
1990 	memcpy(type, p, 1);
1991 
1992 	if (*len < MSGSIZE_HEADER || *len > MAX_PKTSIZE) {
1993 		log_peer_warnx(&peer->conf,
1994 		    "received message: illegal length: %u byte", *len);
1995 		session_notification(peer, ERR_HEADER, ERR_HDR_LEN,
1996 		    &olen, sizeof(olen));
1997 		bgp_fsm(peer, EVNT_CON_FATAL);
1998 		return (-1);
1999 	}
2000 
2001 	switch (*type) {
2002 	case OPEN:
2003 		if (*len < MSGSIZE_OPEN_MIN) {
2004 			log_peer_warnx(&peer->conf,
2005 			    "received OPEN: illegal len: %u byte", *len);
2006 			session_notification(peer, ERR_HEADER, ERR_HDR_LEN,
2007 			    &olen, sizeof(olen));
2008 			bgp_fsm(peer, EVNT_CON_FATAL);
2009 			return (-1);
2010 		}
2011 		break;
2012 	case NOTIFICATION:
2013 		if (*len < MSGSIZE_NOTIFICATION_MIN) {
2014 			log_peer_warnx(&peer->conf,
2015 			    "received NOTIFICATION: illegal len: %u byte",
2016 			    *len);
2017 			session_notification(peer, ERR_HEADER, ERR_HDR_LEN,
2018 			    &olen, sizeof(olen));
2019 			bgp_fsm(peer, EVNT_CON_FATAL);
2020 			return (-1);
2021 		}
2022 		break;
2023 	case UPDATE:
2024 		if (*len < MSGSIZE_UPDATE_MIN) {
2025 			log_peer_warnx(&peer->conf,
2026 			    "received UPDATE: illegal len: %u byte", *len);
2027 			session_notification(peer, ERR_HEADER, ERR_HDR_LEN,
2028 			    &olen, sizeof(olen));
2029 			bgp_fsm(peer, EVNT_CON_FATAL);
2030 			return (-1);
2031 		}
2032 		break;
2033 	case KEEPALIVE:
2034 		if (*len != MSGSIZE_KEEPALIVE) {
2035 			log_peer_warnx(&peer->conf,
2036 			    "received KEEPALIVE: illegal len: %u byte", *len);
2037 			session_notification(peer, ERR_HEADER, ERR_HDR_LEN,
2038 			    &olen, sizeof(olen));
2039 			bgp_fsm(peer, EVNT_CON_FATAL);
2040 			return (-1);
2041 		}
2042 		break;
2043 	case RREFRESH:
2044 		if (*len < MSGSIZE_RREFRESH_MIN) {
2045 			log_peer_warnx(&peer->conf,
2046 			    "received RREFRESH: illegal len: %u byte", *len);
2047 			session_notification(peer, ERR_HEADER, ERR_HDR_LEN,
2048 			    &olen, sizeof(olen));
2049 			bgp_fsm(peer, EVNT_CON_FATAL);
2050 			return (-1);
2051 		}
2052 		break;
2053 	default:
2054 		log_peer_warnx(&peer->conf,
2055 		    "received msg with unknown type %u", *type);
2056 		session_notification(peer, ERR_HEADER, ERR_HDR_TYPE,
2057 		    type, 1);
2058 		bgp_fsm(peer, EVNT_CON_FATAL);
2059 		return (-1);
2060 	}
2061 	return (0);
2062 }
2063 
2064 int
2065 parse_open(struct peer *peer)
2066 {
2067 	u_char		*p, *op_val;
2068 	uint8_t		 version, rversion;
2069 	uint16_t	 short_as, msglen;
2070 	uint16_t	 holdtime, oholdtime, myholdtime;
2071 	uint32_t	 as, bgpid;
2072 	uint16_t	 optparamlen, extlen, plen, op_len;
2073 	uint8_t		 op_type;
2074 
2075 	p = peer->rbuf->rptr;
2076 	p += MSGSIZE_HEADER_MARKER;
2077 	memcpy(&msglen, p, sizeof(msglen));
2078 	msglen = ntohs(msglen);
2079 
2080 	p = peer->rbuf->rptr;
2081 	p += MSGSIZE_HEADER;	/* header is already checked */
2082 
2083 	memcpy(&version, p, sizeof(version));
2084 	p += sizeof(version);
2085 
2086 	if (version != BGP_VERSION) {
2087 		log_peer_warnx(&peer->conf,
2088 		    "peer wants unrecognized version %u", version);
2089 		if (version > BGP_VERSION)
2090 			rversion = version - BGP_VERSION;
2091 		else
2092 			rversion = BGP_VERSION;
2093 		session_notification(peer, ERR_OPEN, ERR_OPEN_VERSION,
2094 		    &rversion, sizeof(rversion));
2095 		change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2096 		return (-1);
2097 	}
2098 
2099 	memcpy(&short_as, p, sizeof(short_as));
2100 	p += sizeof(short_as);
2101 	as = peer->short_as = ntohs(short_as);
2102 	if (as == 0) {
2103 		log_peer_warnx(&peer->conf,
2104 		    "peer requests unacceptable AS %u", as);
2105 		session_notification(peer, ERR_OPEN, ERR_OPEN_AS,
2106 		    NULL, 0);
2107 		change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2108 		return (-1);
2109 	}
2110 
2111 	memcpy(&oholdtime, p, sizeof(oholdtime));
2112 	p += sizeof(oholdtime);
2113 
2114 	holdtime = ntohs(oholdtime);
2115 	if (holdtime && holdtime < peer->conf.min_holdtime) {
2116 		log_peer_warnx(&peer->conf,
2117 		    "peer requests unacceptable holdtime %u", holdtime);
2118 		session_notification(peer, ERR_OPEN, ERR_OPEN_HOLDTIME,
2119 		    NULL, 0);
2120 		change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2121 		return (-1);
2122 	}
2123 
2124 	myholdtime = peer->conf.holdtime;
2125 	if (!myholdtime)
2126 		myholdtime = conf->holdtime;
2127 	if (holdtime < myholdtime)
2128 		peer->holdtime = holdtime;
2129 	else
2130 		peer->holdtime = myholdtime;
2131 
2132 	memcpy(&bgpid, p, sizeof(bgpid));
2133 	p += sizeof(bgpid);
2134 
2135 	/* check bgpid for validity - just disallow 0 */
2136 	if (ntohl(bgpid) == 0) {
2137 		log_peer_warnx(&peer->conf, "peer BGPID %u unacceptable",
2138 		    ntohl(bgpid));
2139 		session_notification(peer, ERR_OPEN, ERR_OPEN_BGPID,
2140 		    NULL, 0);
2141 		change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2142 		return (-1);
2143 	}
2144 	peer->remote_bgpid = bgpid;
2145 
2146 	extlen = 0;
2147 	optparamlen = *p++;
2148 
2149 	if (optparamlen == 0) {
2150 		if (msglen != MSGSIZE_OPEN_MIN) {
2151 bad_len:
2152 			log_peer_warnx(&peer->conf,
2153 			    "corrupt OPEN message received: length mismatch");
2154 			session_notification(peer, ERR_OPEN, 0, NULL, 0);
2155 			change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2156 			return (-1);
2157 		}
2158 	} else {
2159 		if (msglen < MSGSIZE_OPEN_MIN + 1)
2160 			goto bad_len;
2161 
2162 		op_type = *p;
2163 		if (op_type == OPT_PARAM_EXT_LEN) {
2164 			p++;
2165 			memcpy(&optparamlen, p, sizeof(optparamlen));
2166 			optparamlen = ntohs(optparamlen);
2167 			p += sizeof(optparamlen);
2168 			extlen = 1;
2169 		}
2170 
2171 		/* RFC9020 encoding has 3 extra bytes */
2172 		if (optparamlen + 3 * extlen != msglen - MSGSIZE_OPEN_MIN)
2173 			goto bad_len;
2174 	}
2175 
2176 	plen = optparamlen;
2177 	while (plen > 0) {
2178 		if (plen < 2 + extlen)
2179 			goto bad_len;
2180 
2181 		memcpy(&op_type, p, sizeof(op_type));
2182 		p += sizeof(op_type);
2183 		plen -= sizeof(op_type);
2184 		if (!extlen) {
2185 			op_len = *p++;
2186 			plen--;
2187 		} else {
2188 			memcpy(&op_len, p, sizeof(op_len));
2189 			op_len = ntohs(op_len);
2190 			p += sizeof(op_len);
2191 			plen -= sizeof(op_len);
2192 		}
2193 		if (op_len > 0) {
2194 			if (plen < op_len)
2195 				goto bad_len;
2196 			op_val = p;
2197 			p += op_len;
2198 			plen -= op_len;
2199 		} else
2200 			op_val = NULL;
2201 
2202 		switch (op_type) {
2203 		case OPT_PARAM_CAPABILITIES:		/* RFC 3392 */
2204 			if (parse_capabilities(peer, op_val, op_len,
2205 			    &as) == -1) {
2206 				session_notification(peer, ERR_OPEN, 0,
2207 				    NULL, 0);
2208 				change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2209 				return (-1);
2210 			}
2211 			break;
2212 		case OPT_PARAM_AUTH:			/* deprecated */
2213 		default:
2214 			/*
2215 			 * unsupported type
2216 			 * the RFCs tell us to leave the data section empty
2217 			 * and notify the peer with ERR_OPEN, ERR_OPEN_OPT.
2218 			 * How the peer should know _which_ optional parameter
2219 			 * we don't support is beyond me.
2220 			 */
2221 			log_peer_warnx(&peer->conf,
2222 			    "received OPEN message with unsupported optional "
2223 			    "parameter: type %u", op_type);
2224 			session_notification(peer, ERR_OPEN, ERR_OPEN_OPT,
2225 				NULL, 0);
2226 			change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2227 			/* no punish */
2228 			timer_set(&peer->timers, Timer_IdleHold, 0);
2229 			peer->IdleHoldTime /= 2;
2230 			return (-1);
2231 		}
2232 	}
2233 
2234 	/* if remote-as is zero and it's a cloned neighbor, accept any */
2235 	if (peer->template && !peer->conf.remote_as && as != AS_TRANS) {
2236 		peer->conf.remote_as = as;
2237 		peer->conf.ebgp = (peer->conf.remote_as != peer->conf.local_as);
2238 		if (!peer->conf.ebgp)
2239 			/* force enforce_as off for iBGP sessions */
2240 			peer->conf.enforce_as = ENFORCE_AS_OFF;
2241 	}
2242 
2243 	if (peer->conf.remote_as != as) {
2244 		log_peer_warnx(&peer->conf, "peer sent wrong AS %s",
2245 		    log_as(as));
2246 		session_notification(peer, ERR_OPEN, ERR_OPEN_AS, NULL, 0);
2247 		change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2248 		return (-1);
2249 	}
2250 
2251 	/* on iBGP sessions check for bgpid collision */
2252 	if (!peer->conf.ebgp && peer->remote_bgpid == conf->bgpid) {
2253 		log_peer_warnx(&peer->conf, "peer BGPID %u conflicts with ours",
2254 		    ntohl(bgpid));
2255 		session_notification(peer, ERR_OPEN, ERR_OPEN_BGPID,
2256 		    NULL, 0);
2257 		change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2258 		return (-1);
2259 	}
2260 
2261 	if (capa_neg_calc(peer) == -1) {
2262 		log_peer_warnx(&peer->conf,
2263 		    "capability negotiation calculation failed");
2264 		session_notification(peer, ERR_OPEN, 0, NULL, 0);
2265 		change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2266 		return (-1);
2267 	}
2268 
2269 	return (0);
2270 }
2271 
2272 int
2273 parse_update(struct peer *peer)
2274 {
2275 	u_char		*p;
2276 	uint16_t	 datalen;
2277 
2278 	/*
2279 	 * we pass the message verbatim to the rde.
2280 	 * in case of errors the whole session is reset with a
2281 	 * notification anyway, we only need to know the peer
2282 	 */
2283 	p = peer->rbuf->rptr;
2284 	p += MSGSIZE_HEADER_MARKER;
2285 	memcpy(&datalen, p, sizeof(datalen));
2286 	datalen = ntohs(datalen);
2287 
2288 	p = peer->rbuf->rptr;
2289 	p += MSGSIZE_HEADER;	/* header is already checked */
2290 	datalen -= MSGSIZE_HEADER;
2291 
2292 	if (imsg_rde(IMSG_UPDATE, peer->conf.id, p, datalen) == -1)
2293 		return (-1);
2294 
2295 	return (0);
2296 }
2297 
2298 int
2299 parse_rrefresh(struct peer *peer)
2300 {
2301 	struct route_refresh rr;
2302 	uint16_t afi, datalen;
2303 	uint8_t aid, safi, subtype;
2304 	u_char *p;
2305 
2306 	p = peer->rbuf->rptr;
2307 	p += MSGSIZE_HEADER_MARKER;
2308 	memcpy(&datalen, p, sizeof(datalen));
2309 	datalen = ntohs(datalen);
2310 
2311 	p = peer->rbuf->rptr;
2312 	p += MSGSIZE_HEADER;	/* header is already checked */
2313 
2314 	/*
2315 	 * We could check if we actually announced the capability but
2316 	 * as long as the message is correctly encoded we don't care.
2317 	 */
2318 
2319 	/* afi, 2 byte */
2320 	memcpy(&afi, p, sizeof(afi));
2321 	afi = ntohs(afi);
2322 	p += 2;
2323 	/* subtype, 1 byte */
2324 	subtype = *p;
2325 	p += 1;
2326 	/* safi, 1 byte */
2327 	safi = *p;
2328 
2329 	/* check subtype if peer announced enhanced route refresh */
2330 	if (peer->capa.neg.enhanced_rr) {
2331 		switch (subtype) {
2332 		case ROUTE_REFRESH_REQUEST:
2333 			/* no ORF support, so no oversized RREFRESH msgs */
2334 			if (datalen != MSGSIZE_RREFRESH) {
2335 				log_peer_warnx(&peer->conf,
2336 				    "received RREFRESH: illegal len: %u byte",
2337 				    datalen);
2338 				datalen = htons(datalen);
2339 				session_notification(peer, ERR_HEADER,
2340 				    ERR_HDR_LEN, &datalen, sizeof(datalen));
2341 				bgp_fsm(peer, EVNT_CON_FATAL);
2342 				return (-1);
2343 			}
2344 			peer->stats.refresh_rcvd_req++;
2345 			break;
2346 		case ROUTE_REFRESH_BEGIN_RR:
2347 		case ROUTE_REFRESH_END_RR:
2348 			/* special handling for RFC7313 */
2349 			if (datalen != MSGSIZE_RREFRESH) {
2350 				log_peer_warnx(&peer->conf,
2351 				    "received RREFRESH: illegal len: %u byte",
2352 				    datalen);
2353 				p = peer->rbuf->rptr;
2354 				p += MSGSIZE_HEADER;
2355 				datalen -= MSGSIZE_HEADER;
2356 				session_notification(peer, ERR_RREFRESH,
2357 				    ERR_RR_INV_LEN, p, datalen);
2358 				bgp_fsm(peer, EVNT_CON_FATAL);
2359 				return (-1);
2360 			}
2361 			if (subtype == ROUTE_REFRESH_BEGIN_RR)
2362 				peer->stats.refresh_rcvd_borr++;
2363 			else
2364 				peer->stats.refresh_rcvd_eorr++;
2365 			break;
2366 		default:
2367 			log_peer_warnx(&peer->conf, "peer sent bad refresh, "
2368 			    "bad subtype %d", subtype);
2369 			return (0);
2370 		}
2371 	} else {
2372 		/* force subtype to default */
2373 		subtype = ROUTE_REFRESH_REQUEST;
2374 		peer->stats.refresh_rcvd_req++;
2375 	}
2376 
2377 	/* afi/safi unchecked -	unrecognized values will be ignored anyway */
2378 	if (afi2aid(afi, safi, &aid) == -1) {
2379 		log_peer_warnx(&peer->conf, "peer sent bad refresh, "
2380 		    "invalid afi/safi pair");
2381 		return (0);
2382 	}
2383 
2384 	if (!peer->capa.neg.refresh && !peer->capa.neg.enhanced_rr) {
2385 		log_peer_warnx(&peer->conf, "peer sent unexpected refresh");
2386 		return (0);
2387 	}
2388 
2389 	rr.aid = aid;
2390 	rr.subtype = subtype;
2391 
2392 	if (imsg_rde(IMSG_REFRESH, peer->conf.id, &rr, sizeof(rr)) == -1)
2393 		return (-1);
2394 
2395 	return (0);
2396 }
2397 
2398 int
2399 parse_notification(struct peer *peer)
2400 {
2401 	u_char		*p;
2402 	uint16_t	 datalen;
2403 	uint8_t		 errcode;
2404 	uint8_t		 subcode;
2405 	uint8_t		 capa_code;
2406 	uint8_t		 capa_len;
2407 	size_t		 reason_len;
2408 	uint8_t		 i;
2409 
2410 	/* just log */
2411 	p = peer->rbuf->rptr;
2412 	p += MSGSIZE_HEADER_MARKER;
2413 	memcpy(&datalen, p, sizeof(datalen));
2414 	datalen = ntohs(datalen);
2415 
2416 	p = peer->rbuf->rptr;
2417 	p += MSGSIZE_HEADER;	/* header is already checked */
2418 	datalen -= MSGSIZE_HEADER;
2419 
2420 	memcpy(&errcode, p, sizeof(errcode));
2421 	p += sizeof(errcode);
2422 	datalen -= sizeof(errcode);
2423 
2424 	memcpy(&subcode, p, sizeof(subcode));
2425 	p += sizeof(subcode);
2426 	datalen -= sizeof(subcode);
2427 
2428 	log_notification(peer, errcode, subcode, p, datalen, "received");
2429 	peer->errcnt++;
2430 	peer->stats.last_rcvd_errcode = errcode;
2431 	peer->stats.last_rcvd_suberr = subcode;
2432 
2433 	if (errcode == ERR_OPEN && subcode == ERR_OPEN_CAPA) {
2434 		if (datalen == 0) {	/* zebra likes to send those.. humbug */
2435 			log_peer_warnx(&peer->conf, "received \"unsupported "
2436 			    "capability\" notification without data part, "
2437 			    "disabling capability announcements altogether");
2438 			session_capa_ann_none(peer);
2439 		}
2440 
2441 		while (datalen > 0) {
2442 			if (datalen < 2) {
2443 				log_peer_warnx(&peer->conf,
2444 				    "parse_notification: "
2445 				    "expect len >= 2, len is %u", datalen);
2446 				return (-1);
2447 			}
2448 			memcpy(&capa_code, p, sizeof(capa_code));
2449 			p += sizeof(capa_code);
2450 			datalen -= sizeof(capa_code);
2451 			memcpy(&capa_len, p, sizeof(capa_len));
2452 			p += sizeof(capa_len);
2453 			datalen -= sizeof(capa_len);
2454 			if (datalen < capa_len) {
2455 				log_peer_warnx(&peer->conf,
2456 				    "parse_notification: capa_len %u exceeds "
2457 				    "remaining msg length %u", capa_len,
2458 				    datalen);
2459 				return (-1);
2460 			}
2461 			p += capa_len;
2462 			datalen -= capa_len;
2463 			switch (capa_code) {
2464 			case CAPA_MP:
2465 				for (i = 0; i < AID_MAX; i++)
2466 					peer->capa.ann.mp[i] = 0;
2467 				log_peer_warnx(&peer->conf,
2468 				    "disabling multiprotocol capability");
2469 				break;
2470 			case CAPA_REFRESH:
2471 				peer->capa.ann.refresh = 0;
2472 				log_peer_warnx(&peer->conf,
2473 				    "disabling route refresh capability");
2474 				break;
2475 			case CAPA_RESTART:
2476 				peer->capa.ann.grestart.restart = 0;
2477 				log_peer_warnx(&peer->conf,
2478 				    "disabling restart capability");
2479 				break;
2480 			case CAPA_AS4BYTE:
2481 				peer->capa.ann.as4byte = 0;
2482 				log_peer_warnx(&peer->conf,
2483 				    "disabling 4-byte AS num capability");
2484 				break;
2485 			case CAPA_ADD_PATH:
2486 				memset(peer->capa.ann.add_path, 0,
2487 				    sizeof(peer->capa.ann.add_path));
2488 				log_peer_warnx(&peer->conf,
2489 				    "disabling ADD-PATH capability");
2490 				break;
2491 			case CAPA_ENHANCED_RR:
2492 				peer->capa.ann.enhanced_rr = 0;
2493 				log_peer_warnx(&peer->conf,
2494 				    "disabling enhanced route refresh "
2495 				    "capability");
2496 				break;
2497 			default:	/* should not happen... */
2498 				log_peer_warnx(&peer->conf, "received "
2499 				    "\"unsupported capability\" notification "
2500 				    "for unknown capability %u, disabling "
2501 				    "capability announcements altogether",
2502 				    capa_code);
2503 				session_capa_ann_none(peer);
2504 				break;
2505 			}
2506 		}
2507 
2508 		return (1);
2509 	}
2510 
2511 	if (errcode == ERR_OPEN && subcode == ERR_OPEN_OPT) {
2512 		session_capa_ann_none(peer);
2513 		return (1);
2514 	}
2515 
2516 	if (errcode == ERR_CEASE &&
2517 	    (subcode == ERR_CEASE_ADMIN_DOWN ||
2518 	     subcode == ERR_CEASE_ADMIN_RESET)) {
2519 		if (datalen > 1) {
2520 			reason_len = *p++;
2521 			datalen--;
2522 			if (datalen < reason_len) {
2523 			    log_peer_warnx(&peer->conf,
2524 				"received truncated shutdown reason");
2525 			    return (0);
2526 			}
2527 			if (reason_len > REASON_LEN - 1) {
2528 			    log_peer_warnx(&peer->conf,
2529 				"received overly long shutdown reason");
2530 			    return (0);
2531 			}
2532 			memcpy(peer->stats.last_reason, p, reason_len);
2533 			peer->stats.last_reason[reason_len] = '\0';
2534 			log_peer_warnx(&peer->conf,
2535 			    "received shutdown reason: \"%s\"",
2536 			    log_reason(peer->stats.last_reason));
2537 			p += reason_len;
2538 			datalen -= reason_len;
2539 		}
2540 	}
2541 
2542 	return (0);
2543 }
2544 
2545 int
2546 parse_capabilities(struct peer *peer, u_char *d, uint16_t dlen, uint32_t *as)
2547 {
2548 	u_char		*capa_val;
2549 	uint32_t	 remote_as;
2550 	uint16_t	 len;
2551 	uint16_t	 afi;
2552 	uint16_t	 gr_header;
2553 	uint8_t		 safi;
2554 	uint8_t		 aid;
2555 	uint8_t		 flags;
2556 	uint8_t		 capa_code;
2557 	uint8_t		 capa_len;
2558 	uint8_t		 i;
2559 
2560 	len = dlen;
2561 	while (len > 0) {
2562 		if (len < 2) {
2563 			log_peer_warnx(&peer->conf, "Bad capabilities attr "
2564 			    "length: %u, too short", len);
2565 			return (-1);
2566 		}
2567 		memcpy(&capa_code, d, sizeof(capa_code));
2568 		d += sizeof(capa_code);
2569 		len -= sizeof(capa_code);
2570 		memcpy(&capa_len, d, sizeof(capa_len));
2571 		d += sizeof(capa_len);
2572 		len -= sizeof(capa_len);
2573 		if (capa_len > 0) {
2574 			if (len < capa_len) {
2575 				log_peer_warnx(&peer->conf,
2576 				    "Bad capabilities attr length: "
2577 				    "len %u smaller than capa_len %u",
2578 				    len, capa_len);
2579 				return (-1);
2580 			}
2581 			capa_val = d;
2582 			d += capa_len;
2583 			len -= capa_len;
2584 		} else
2585 			capa_val = NULL;
2586 
2587 		switch (capa_code) {
2588 		case CAPA_MP:			/* RFC 4760 */
2589 			if (capa_len != 4) {
2590 				log_peer_warnx(&peer->conf,
2591 				    "Bad multi protocol capability length: "
2592 				    "%u", capa_len);
2593 				break;
2594 			}
2595 			memcpy(&afi, capa_val, sizeof(afi));
2596 			afi = ntohs(afi);
2597 			memcpy(&safi, capa_val + 3, sizeof(safi));
2598 			if (afi2aid(afi, safi, &aid) == -1) {
2599 				log_peer_warnx(&peer->conf,
2600 				    "Received multi protocol capability: "
2601 				    " unknown AFI %u, safi %u pair",
2602 				    afi, safi);
2603 				break;
2604 			}
2605 			peer->capa.peer.mp[aid] = 1;
2606 			break;
2607 		case CAPA_REFRESH:
2608 			peer->capa.peer.refresh = 1;
2609 			break;
2610 		case CAPA_RESTART:
2611 			if (capa_len == 2) {
2612 				/* peer only supports EoR marker */
2613 				peer->capa.peer.grestart.restart = 1;
2614 				peer->capa.peer.grestart.timeout = 0;
2615 				break;
2616 			} else if (capa_len % 4 != 2) {
2617 				log_peer_warnx(&peer->conf,
2618 				    "Bad graceful restart capability length: "
2619 				    "%u", capa_len);
2620 				peer->capa.peer.grestart.restart = 0;
2621 				peer->capa.peer.grestart.timeout = 0;
2622 				break;
2623 			}
2624 
2625 			memcpy(&gr_header, capa_val, sizeof(gr_header));
2626 			gr_header = ntohs(gr_header);
2627 			peer->capa.peer.grestart.timeout =
2628 			    gr_header & CAPA_GR_TIMEMASK;
2629 			if (peer->capa.peer.grestart.timeout == 0) {
2630 				log_peer_warnx(&peer->conf, "Received "
2631 				    "graceful restart timeout is zero");
2632 				peer->capa.peer.grestart.restart = 0;
2633 				break;
2634 			}
2635 
2636 			for (i = 2; i <= capa_len - 4; i += 4) {
2637 				memcpy(&afi, capa_val + i, sizeof(afi));
2638 				afi = ntohs(afi);
2639 				safi = capa_val[i + 2];
2640 				flags = capa_val[i + 3];
2641 				if (afi2aid(afi, safi, &aid) == -1) {
2642 					log_peer_warnx(&peer->conf,
2643 					    "Received graceful restart capa: "
2644 					    " unknown AFI %u, safi %u pair",
2645 					    afi, safi);
2646 					continue;
2647 				}
2648 				peer->capa.peer.grestart.flags[aid] |=
2649 				    CAPA_GR_PRESENT;
2650 				if (flags & CAPA_GR_F_FLAG)
2651 					peer->capa.peer.grestart.flags[aid] |=
2652 					    CAPA_GR_FORWARD;
2653 				if (gr_header & CAPA_GR_R_FLAG)
2654 					peer->capa.peer.grestart.flags[aid] |=
2655 					    CAPA_GR_RESTART;
2656 				peer->capa.peer.grestart.restart = 2;
2657 			}
2658 			break;
2659 		case CAPA_AS4BYTE:
2660 			if (capa_len != 4) {
2661 				log_peer_warnx(&peer->conf,
2662 				    "Bad AS4BYTE capability length: "
2663 				    "%u", capa_len);
2664 				peer->capa.peer.as4byte = 0;
2665 				break;
2666 			}
2667 			memcpy(&remote_as, capa_val, sizeof(remote_as));
2668 			*as = ntohl(remote_as);
2669 			if (*as == 0) {
2670 				log_peer_warnx(&peer->conf,
2671 				    "peer requests unacceptable AS %u", *as);
2672 				session_notification(peer, ERR_OPEN,
2673 				    ERR_OPEN_AS, NULL, 0);
2674 				change_state(peer, STATE_IDLE, EVNT_RCVD_OPEN);
2675 				return (-1);
2676 			}
2677 			peer->capa.peer.as4byte = 1;
2678 			break;
2679 		case CAPA_ADD_PATH:
2680 			if (capa_len % 4 != 0) {
2681 				log_peer_warnx(&peer->conf,
2682 				    "Bad ADD-PATH capability length: "
2683 				    "%u", capa_len);
2684 				memset(peer->capa.peer.add_path, 0,
2685 				    sizeof(peer->capa.peer.add_path));
2686 				break;
2687 			}
2688 			for (i = 0; i <= capa_len - 4; i += 4) {
2689 				memcpy(&afi, capa_val + i, sizeof(afi));
2690 				afi = ntohs(afi);
2691 				safi = capa_val[i + 2];
2692 				flags = capa_val[i + 3];
2693 				if (afi2aid(afi, safi, &aid) == -1) {
2694 					log_peer_warnx(&peer->conf,
2695 					    "Received ADD-PATH capa: "
2696 					    " unknown AFI %u, safi %u pair",
2697 					    afi, safi);
2698 					memset(peer->capa.peer.add_path, 0,
2699 					    sizeof(peer->capa.peer.add_path));
2700 					break;
2701 				}
2702 				if (flags & ~CAPA_AP_BIDIR) {
2703 					log_peer_warnx(&peer->conf,
2704 					    "Received ADD-PATH capa: "
2705 					    " bad flags %x", flags);
2706 					memset(peer->capa.peer.add_path, 0,
2707 					    sizeof(peer->capa.peer.add_path));
2708 					break;
2709 				}
2710 				peer->capa.peer.add_path[aid] = flags;
2711 			}
2712 			break;
2713 		case CAPA_ENHANCED_RR:
2714 			peer->capa.peer.enhanced_rr = 1;
2715 			break;
2716 		default:
2717 			break;
2718 		}
2719 	}
2720 
2721 	return (0);
2722 }
2723 
2724 int
2725 capa_neg_calc(struct peer *p)
2726 {
2727 	uint8_t	i, hasmp = 0;
2728 
2729 	/* a capability is accepted only if both sides announced it */
2730 
2731 	p->capa.neg.refresh =
2732 	    (p->capa.ann.refresh && p->capa.peer.refresh) != 0;
2733 	p->capa.neg.enhanced_rr =
2734 	    (p->capa.ann.enhanced_rr && p->capa.peer.enhanced_rr) != 0;
2735 
2736 	p->capa.neg.as4byte =
2737 	    (p->capa.ann.as4byte && p->capa.peer.as4byte) != 0;
2738 
2739 	/* MP: both side must agree on the AFI,SAFI pair */
2740 	for (i = 0; i < AID_MAX; i++) {
2741 		if (p->capa.ann.mp[i] && p->capa.peer.mp[i])
2742 			p->capa.neg.mp[i] = 1;
2743 		else
2744 			p->capa.neg.mp[i] = 0;
2745 		if (p->capa.ann.mp[i])
2746 			hasmp = 1;
2747 	}
2748 	/* if no MP capability present default to IPv4 unicast mode */
2749 	if (!hasmp)
2750 		p->capa.neg.mp[AID_INET] = 1;
2751 
2752 	/*
2753 	 * graceful restart: the peer capabilities are of interest here.
2754 	 * It is necessary to compare the new values with the previous ones
2755 	 * and act acordingly. AFI/SAFI that are not part in the MP capability
2756 	 * are treated as not being present.
2757 	 * Also make sure that a flush happens if the session stopped
2758 	 * supporting graceful restart.
2759 	 */
2760 
2761 	for (i = 0; i < AID_MAX; i++) {
2762 		int8_t	negflags;
2763 
2764 		/* disable GR if the AFI/SAFI is not present */
2765 		if ((p->capa.peer.grestart.flags[i] & CAPA_GR_PRESENT &&
2766 		    p->capa.neg.mp[i] == 0))
2767 			p->capa.peer.grestart.flags[i] = 0;	/* disable */
2768 		/* look at current GR state and decide what to do */
2769 		negflags = p->capa.neg.grestart.flags[i];
2770 		p->capa.neg.grestart.flags[i] = p->capa.peer.grestart.flags[i];
2771 		if (negflags & CAPA_GR_RESTARTING) {
2772 			if (p->capa.ann.grestart.restart != 0 &&
2773 			    p->capa.peer.grestart.flags[i] & CAPA_GR_FORWARD) {
2774 				p->capa.neg.grestart.flags[i] |=
2775 				    CAPA_GR_RESTARTING;
2776 			} else {
2777 				if (imsg_rde(IMSG_SESSION_FLUSH, p->conf.id,
2778 				    &i, sizeof(i)) == -1)
2779 					return (-1);
2780 				log_peer_warnx(&p->conf, "graceful restart of "
2781 				    "%s, not restarted, flushing", aid2str(i));
2782 			}
2783 		}
2784 	}
2785 	p->capa.neg.grestart.timeout = p->capa.peer.grestart.timeout;
2786 	p->capa.neg.grestart.restart = p->capa.peer.grestart.restart;
2787 	if (p->capa.ann.grestart.restart == 0)
2788 		p->capa.neg.grestart.restart = 0;
2789 
2790 
2791 	/*
2792 	 * ADD-PATH: set only those bits where both sides agree.
2793 	 * For this compare our send bit with the recv bit from the peer
2794 	 * and vice versa.
2795 	 * The flags are stored from this systems view point.
2796 	 */
2797 	memset(p->capa.neg.add_path, 0, sizeof(p->capa.neg.add_path));
2798 	if (p->capa.ann.add_path[0]) {
2799 		for (i = AID_MIN; i < AID_MAX; i++) {
2800 			if ((p->capa.ann.add_path[i] & CAPA_AP_RECV) &&
2801 			    (p->capa.peer.add_path[i] & CAPA_AP_SEND)) {
2802 				p->capa.neg.add_path[i] |= CAPA_AP_RECV;
2803 				p->capa.neg.add_path[0] |= CAPA_AP_RECV;
2804 			}
2805 			if ((p->capa.ann.add_path[i] & CAPA_AP_SEND) &&
2806 			    (p->capa.peer.add_path[i] & CAPA_AP_RECV)) {
2807 				p->capa.neg.add_path[i] |= CAPA_AP_SEND;
2808 				p->capa.neg.add_path[0] |= CAPA_AP_SEND;
2809 			}
2810 		}
2811 	}
2812 
2813 	return (0);
2814 }
2815 
2816 void
2817 session_dispatch_imsg(struct imsgbuf *ibuf, int idx, u_int *listener_cnt)
2818 {
2819 	struct imsg		 imsg;
2820 	struct mrt		 xmrt;
2821 	struct route_refresh	 rr;
2822 	struct mrt		*mrt;
2823 	struct imsgbuf		*i;
2824 	struct peer		*p;
2825 	struct listen_addr	*la, *nla;
2826 	struct kif		*kif;
2827 	u_char			*data;
2828 	int			 n, fd, depend_ok, restricted;
2829 	uint16_t		 t;
2830 	uint8_t			 aid, errcode, subcode;
2831 
2832 	while (ibuf) {
2833 		if ((n = imsg_get(ibuf, &imsg)) == -1)
2834 			fatal("session_dispatch_imsg: imsg_get error");
2835 
2836 		if (n == 0)
2837 			break;
2838 
2839 		switch (imsg.hdr.type) {
2840 		case IMSG_SOCKET_CONN:
2841 		case IMSG_SOCKET_CONN_CTL:
2842 			if (idx != PFD_PIPE_MAIN)
2843 				fatalx("reconf request not from parent");
2844 			if ((fd = imsg.fd) == -1) {
2845 				log_warnx("expected to receive imsg fd to "
2846 				    "RDE but didn't receive any");
2847 				break;
2848 			}
2849 			if ((i = malloc(sizeof(struct imsgbuf))) == NULL)
2850 				fatal(NULL);
2851 			imsg_init(i, fd);
2852 			if (imsg.hdr.type == IMSG_SOCKET_CONN) {
2853 				if (ibuf_rde) {
2854 					log_warnx("Unexpected imsg connection "
2855 					    "to RDE received");
2856 					msgbuf_clear(&ibuf_rde->w);
2857 					free(ibuf_rde);
2858 				}
2859 				ibuf_rde = i;
2860 			} else {
2861 				if (ibuf_rde_ctl) {
2862 					log_warnx("Unexpected imsg ctl "
2863 					    "connection to RDE received");
2864 					msgbuf_clear(&ibuf_rde_ctl->w);
2865 					free(ibuf_rde_ctl);
2866 				}
2867 				ibuf_rde_ctl = i;
2868 			}
2869 			break;
2870 		case IMSG_RECONF_CONF:
2871 			if (idx != PFD_PIPE_MAIN)
2872 				fatalx("reconf request not from parent");
2873 			nconf = new_config();
2874 
2875 			copy_config(nconf, imsg.data);
2876 			pending_reconf = 1;
2877 			break;
2878 		case IMSG_RECONF_PEER:
2879 			if (idx != PFD_PIPE_MAIN)
2880 				fatalx("reconf request not from parent");
2881 			if ((p = calloc(1, sizeof(struct peer))) == NULL)
2882 				fatal("new_peer");
2883 			memcpy(&p->conf, imsg.data, sizeof(struct peer_config));
2884 			p->state = p->prev_state = STATE_NONE;
2885 			p->reconf_action = RECONF_REINIT;
2886 			if (RB_INSERT(peer_head, &nconf->peers, p) != NULL)
2887 				fatalx("%s: peer tree is corrupt", __func__);
2888 			break;
2889 		case IMSG_RECONF_LISTENER:
2890 			if (idx != PFD_PIPE_MAIN)
2891 				fatalx("reconf request not from parent");
2892 			if (nconf == NULL)
2893 				fatalx("IMSG_RECONF_LISTENER but no config");
2894 			nla = imsg.data;
2895 			TAILQ_FOREACH(la, conf->listen_addrs, entry)
2896 				if (!la_cmp(la, nla))
2897 					break;
2898 
2899 			if (la == NULL) {
2900 				if (nla->reconf != RECONF_REINIT)
2901 					fatalx("king bula sez: "
2902 					    "expected REINIT");
2903 
2904 				if ((nla->fd = imsg.fd) == -1)
2905 					log_warnx("expected to receive fd for "
2906 					    "%s but didn't receive any",
2907 					    log_sockaddr((struct sockaddr *)
2908 					    &nla->sa, nla->sa_len));
2909 
2910 				la = calloc(1, sizeof(struct listen_addr));
2911 				if (la == NULL)
2912 					fatal(NULL);
2913 				memcpy(&la->sa, &nla->sa, sizeof(la->sa));
2914 				la->flags = nla->flags;
2915 				la->fd = nla->fd;
2916 				la->reconf = RECONF_REINIT;
2917 				TAILQ_INSERT_TAIL(nconf->listen_addrs, la,
2918 				    entry);
2919 			} else {
2920 				if (nla->reconf != RECONF_KEEP)
2921 					fatalx("king bula sez: expected KEEP");
2922 				la->reconf = RECONF_KEEP;
2923 			}
2924 
2925 			break;
2926 		case IMSG_RECONF_CTRL:
2927 			if (idx != PFD_PIPE_MAIN)
2928 				fatalx("reconf request not from parent");
2929 			if (imsg.hdr.len != IMSG_HEADER_SIZE +
2930 			    sizeof(restricted))
2931 				fatalx("IFINFO imsg with wrong len");
2932 			memcpy(&restricted, imsg.data, sizeof(restricted));
2933 			if (imsg.fd == -1) {
2934 				log_warnx("expected to receive fd for control "
2935 				    "socket but didn't receive any");
2936 				break;
2937 			}
2938 			if (restricted) {
2939 				control_shutdown(rcsock);
2940 				rcsock = imsg.fd;
2941 			} else {
2942 				control_shutdown(csock);
2943 				csock = imsg.fd;
2944 			}
2945 			break;
2946 		case IMSG_RECONF_DRAIN:
2947 			switch (idx) {
2948 			case PFD_PIPE_ROUTE:
2949 				if (nconf != NULL)
2950 					fatalx("got unexpected %s from RDE",
2951 					    "IMSG_RECONF_DONE");
2952 				imsg_compose(ibuf_main, IMSG_RECONF_DONE, 0, 0,
2953 				    -1, NULL, 0);
2954 				break;
2955 			case PFD_PIPE_MAIN:
2956 				if (nconf == NULL)
2957 					fatalx("got unexpected %s from parent",
2958 					    "IMSG_RECONF_DONE");
2959 				imsg_compose(ibuf_main, IMSG_RECONF_DRAIN, 0, 0,
2960 				    -1, NULL, 0);
2961 				break;
2962 			default:
2963 				fatalx("reconf request not from parent or RDE");
2964 			}
2965 			break;
2966 		case IMSG_RECONF_DONE:
2967 			if (idx != PFD_PIPE_MAIN)
2968 				fatalx("reconf request not from parent");
2969 			if (nconf == NULL)
2970 				fatalx("got IMSG_RECONF_DONE but no config");
2971 			copy_config(conf, nconf);
2972 			merge_peers(conf, nconf);
2973 
2974 			/* delete old listeners */
2975 			for (la = TAILQ_FIRST(conf->listen_addrs); la != NULL;
2976 			    la = nla) {
2977 				nla = TAILQ_NEXT(la, entry);
2978 				if (la->reconf == RECONF_NONE) {
2979 					log_info("not listening on %s any more",
2980 					    log_sockaddr((struct sockaddr *)
2981 					    &la->sa, la->sa_len));
2982 					TAILQ_REMOVE(conf->listen_addrs, la,
2983 					    entry);
2984 					close(la->fd);
2985 					free(la);
2986 				}
2987 			}
2988 
2989 			/* add new listeners */
2990 			TAILQ_CONCAT(conf->listen_addrs, nconf->listen_addrs,
2991 			    entry);
2992 
2993 			setup_listeners(listener_cnt);
2994 			free_config(nconf);
2995 			nconf = NULL;
2996 			pending_reconf = 0;
2997 			log_info("SE reconfigured");
2998 			/*
2999 			 * IMSG_RECONF_DONE is sent when the RDE drained
3000 			 * the peer config sent in merge_peers().
3001 			 */
3002 			break;
3003 		case IMSG_IFINFO:
3004 			if (idx != PFD_PIPE_MAIN)
3005 				fatalx("IFINFO message not from parent");
3006 			if (imsg.hdr.len != IMSG_HEADER_SIZE +
3007 			    sizeof(struct kif))
3008 				fatalx("IFINFO imsg with wrong len");
3009 			kif = imsg.data;
3010 			depend_ok = kif->depend_state;
3011 
3012 			RB_FOREACH(p, peer_head, &conf->peers)
3013 				if (!strcmp(p->conf.if_depend, kif->ifname)) {
3014 					if (depend_ok && !p->depend_ok) {
3015 						p->depend_ok = depend_ok;
3016 						bgp_fsm(p, EVNT_START);
3017 					} else if (!depend_ok && p->depend_ok) {
3018 						p->depend_ok = depend_ok;
3019 						session_stop(p,
3020 						    ERR_CEASE_OTHER_CHANGE);
3021 					}
3022 				}
3023 			break;
3024 		case IMSG_MRT_OPEN:
3025 		case IMSG_MRT_REOPEN:
3026 			if (imsg.hdr.len > IMSG_HEADER_SIZE +
3027 			    sizeof(struct mrt)) {
3028 				log_warnx("wrong imsg len");
3029 				break;
3030 			}
3031 
3032 			memcpy(&xmrt, imsg.data, sizeof(struct mrt));
3033 			if ((xmrt.wbuf.fd = imsg.fd) == -1)
3034 				log_warnx("expected to receive fd for mrt dump "
3035 				    "but didn't receive any");
3036 
3037 			mrt = mrt_get(&mrthead, &xmrt);
3038 			if (mrt == NULL) {
3039 				/* new dump */
3040 				mrt = calloc(1, sizeof(struct mrt));
3041 				if (mrt == NULL)
3042 					fatal("session_dispatch_imsg");
3043 				memcpy(mrt, &xmrt, sizeof(struct mrt));
3044 				TAILQ_INIT(&mrt->wbuf.bufs);
3045 				LIST_INSERT_HEAD(&mrthead, mrt, entry);
3046 			} else {
3047 				/* old dump reopened */
3048 				close(mrt->wbuf.fd);
3049 				mrt->wbuf.fd = xmrt.wbuf.fd;
3050 			}
3051 			break;
3052 		case IMSG_MRT_CLOSE:
3053 			if (imsg.hdr.len > IMSG_HEADER_SIZE +
3054 			    sizeof(struct mrt)) {
3055 				log_warnx("wrong imsg len");
3056 				break;
3057 			}
3058 
3059 			memcpy(&xmrt, imsg.data, sizeof(struct mrt));
3060 			mrt = mrt_get(&mrthead, &xmrt);
3061 			if (mrt != NULL)
3062 				mrt_done(mrt);
3063 			break;
3064 		case IMSG_CTL_KROUTE:
3065 		case IMSG_CTL_KROUTE_ADDR:
3066 		case IMSG_CTL_SHOW_NEXTHOP:
3067 		case IMSG_CTL_SHOW_INTERFACE:
3068 		case IMSG_CTL_SHOW_FIB_TABLES:
3069 		case IMSG_CTL_SHOW_RTR:
3070 		case IMSG_CTL_SHOW_TIMER:
3071 			if (idx != PFD_PIPE_MAIN)
3072 				fatalx("ctl kroute request not from parent");
3073 			control_imsg_relay(&imsg);
3074 			break;
3075 		case IMSG_CTL_SHOW_RIB:
3076 		case IMSG_CTL_SHOW_RIB_PREFIX:
3077 		case IMSG_CTL_SHOW_RIB_COMMUNITIES:
3078 		case IMSG_CTL_SHOW_RIB_ATTR:
3079 		case IMSG_CTL_SHOW_RIB_MEM:
3080 		case IMSG_CTL_SHOW_RIB_HASH:
3081 		case IMSG_CTL_SHOW_NETWORK:
3082 		case IMSG_CTL_SHOW_NEIGHBOR:
3083 		case IMSG_CTL_SHOW_SET:
3084 			if (idx != PFD_PIPE_ROUTE_CTL)
3085 				fatalx("ctl rib request not from RDE");
3086 			control_imsg_relay(&imsg);
3087 			break;
3088 		case IMSG_CTL_END:
3089 		case IMSG_CTL_RESULT:
3090 			control_imsg_relay(&imsg);
3091 			break;
3092 		case IMSG_UPDATE:
3093 			if (idx != PFD_PIPE_ROUTE)
3094 				fatalx("update request not from RDE");
3095 			if (imsg.hdr.len > IMSG_HEADER_SIZE +
3096 			    MAX_PKTSIZE - MSGSIZE_HEADER ||
3097 			    imsg.hdr.len < IMSG_HEADER_SIZE +
3098 			    MSGSIZE_UPDATE_MIN - MSGSIZE_HEADER)
3099 				log_warnx("RDE sent invalid update");
3100 			else
3101 				session_update(imsg.hdr.peerid, imsg.data,
3102 				    imsg.hdr.len - IMSG_HEADER_SIZE);
3103 			break;
3104 		case IMSG_UPDATE_ERR:
3105 			if (idx != PFD_PIPE_ROUTE)
3106 				fatalx("update request not from RDE");
3107 			if (imsg.hdr.len < IMSG_HEADER_SIZE + 2) {
3108 				log_warnx("RDE sent invalid notification");
3109 				break;
3110 			}
3111 			if ((p = getpeerbyid(conf, imsg.hdr.peerid)) == NULL) {
3112 				log_warnx("no such peer: id=%u",
3113 				    imsg.hdr.peerid);
3114 				break;
3115 			}
3116 			data = imsg.data;
3117 			errcode = *data++;
3118 			subcode = *data++;
3119 
3120 			if (imsg.hdr.len == IMSG_HEADER_SIZE + 2)
3121 				data = NULL;
3122 
3123 			session_notification(p, errcode, subcode,
3124 			    data, imsg.hdr.len - IMSG_HEADER_SIZE - 2);
3125 			switch (errcode) {
3126 			case ERR_CEASE:
3127 				switch (subcode) {
3128 				case ERR_CEASE_MAX_PREFIX:
3129 				case ERR_CEASE_MAX_SENT_PREFIX:
3130 					t = p->conf.max_out_prefix_restart;
3131 					if (subcode == ERR_CEASE_MAX_PREFIX)
3132 						t = p->conf.max_prefix_restart;
3133 
3134 					bgp_fsm(p, EVNT_STOP);
3135 					if (t)
3136 						timer_set(&p->timers,
3137 						    Timer_IdleHold, 60 * t);
3138 					break;
3139 				default:
3140 					bgp_fsm(p, EVNT_CON_FATAL);
3141 					break;
3142 				}
3143 				break;
3144 			default:
3145 				bgp_fsm(p, EVNT_CON_FATAL);
3146 				break;
3147 			}
3148 			break;
3149 		case IMSG_REFRESH:
3150 			if (idx != PFD_PIPE_ROUTE)
3151 				fatalx("route refresh request not from RDE");
3152 			if (imsg.hdr.len < IMSG_HEADER_SIZE + sizeof(rr)) {
3153 				log_warnx("RDE sent invalid refresh msg");
3154 				break;
3155 			}
3156 			if ((p = getpeerbyid(conf, imsg.hdr.peerid)) == NULL) {
3157 				log_warnx("no such peer: id=%u",
3158 				    imsg.hdr.peerid);
3159 				break;
3160 			}
3161 			memcpy(&rr, imsg.data, sizeof(rr));
3162 			if (rr.aid >= AID_MAX)
3163 				fatalx("IMSG_REFRESH: bad AID");
3164 			session_rrefresh(p, rr.aid, rr.subtype);
3165 			break;
3166 		case IMSG_SESSION_RESTARTED:
3167 			if (idx != PFD_PIPE_ROUTE)
3168 				fatalx("update request not from RDE");
3169 			if (imsg.hdr.len < IMSG_HEADER_SIZE + sizeof(aid)) {
3170 				log_warnx("RDE sent invalid restart msg");
3171 				break;
3172 			}
3173 			if ((p = getpeerbyid(conf, imsg.hdr.peerid)) == NULL) {
3174 				log_warnx("no such peer: id=%u",
3175 				    imsg.hdr.peerid);
3176 				break;
3177 			}
3178 			memcpy(&aid, imsg.data, sizeof(aid));
3179 			if (aid >= AID_MAX)
3180 				fatalx("IMSG_SESSION_RESTARTED: bad AID");
3181 			if (p->capa.neg.grestart.flags[aid] &
3182 			    CAPA_GR_RESTARTING) {
3183 				log_peer_warnx(&p->conf,
3184 				    "graceful restart of %s finished",
3185 				    aid2str(aid));
3186 				p->capa.neg.grestart.flags[aid] &=
3187 				    ~CAPA_GR_RESTARTING;
3188 				timer_stop(&p->timers, Timer_RestartTimeout);
3189 
3190 				/* signal back to RDE to cleanup stale routes */
3191 				if (imsg_rde(IMSG_SESSION_RESTARTED,
3192 				    imsg.hdr.peerid, &aid, sizeof(aid)) == -1)
3193 					fatal("imsg_compose: "
3194 					    "IMSG_SESSION_RESTARTED");
3195 			}
3196 			break;
3197 		case IMSG_SESSION_DOWN:
3198 			if (idx != PFD_PIPE_ROUTE)
3199 				fatalx("update request not from RDE");
3200 			if ((p = getpeerbyid(conf, imsg.hdr.peerid)) == NULL) {
3201 				log_warnx("no such peer: id=%u",
3202 				    imsg.hdr.peerid);
3203 				break;
3204 			}
3205 			session_stop(p, ERR_CEASE_ADMIN_DOWN);
3206 			break;
3207 		default:
3208 			break;
3209 		}
3210 		imsg_free(&imsg);
3211 	}
3212 }
3213 
3214 int
3215 la_cmp(struct listen_addr *a, struct listen_addr *b)
3216 {
3217 	struct sockaddr_in	*in_a, *in_b;
3218 	struct sockaddr_in6	*in6_a, *in6_b;
3219 
3220 	if (a->sa.ss_family != b->sa.ss_family)
3221 		return (1);
3222 
3223 	switch (a->sa.ss_family) {
3224 	case AF_INET:
3225 		in_a = (struct sockaddr_in *)&a->sa;
3226 		in_b = (struct sockaddr_in *)&b->sa;
3227 		if (in_a->sin_addr.s_addr != in_b->sin_addr.s_addr)
3228 			return (1);
3229 		if (in_a->sin_port != in_b->sin_port)
3230 			return (1);
3231 		break;
3232 	case AF_INET6:
3233 		in6_a = (struct sockaddr_in6 *)&a->sa;
3234 		in6_b = (struct sockaddr_in6 *)&b->sa;
3235 		if (bcmp(&in6_a->sin6_addr, &in6_b->sin6_addr,
3236 		    sizeof(struct in6_addr)))
3237 			return (1);
3238 		if (in6_a->sin6_port != in6_b->sin6_port)
3239 			return (1);
3240 		break;
3241 	default:
3242 		fatal("king bula sez: unknown address family");
3243 		/* NOTREACHED */
3244 	}
3245 
3246 	return (0);
3247 }
3248 
3249 struct peer *
3250 getpeerbydesc(struct bgpd_config *c, const char *descr)
3251 {
3252 	struct peer	*p, *res = NULL;
3253 	int		 match = 0;
3254 
3255 	RB_FOREACH(p, peer_head, &c->peers)
3256 		if (!strcmp(p->conf.descr, descr)) {
3257 			res = p;
3258 			match++;
3259 		}
3260 
3261 	if (match > 1)
3262 		log_info("neighbor description \"%s\" not unique, request "
3263 		    "aborted", descr);
3264 
3265 	if (match == 1)
3266 		return (res);
3267 	else
3268 		return (NULL);
3269 }
3270 
3271 struct peer *
3272 getpeerbyip(struct bgpd_config *c, struct sockaddr *ip)
3273 {
3274 	struct bgpd_addr addr;
3275 	struct peer	*p, *newpeer, *loose = NULL;
3276 	uint32_t	 id;
3277 
3278 	sa2addr(ip, &addr, NULL);
3279 
3280 	/* we might want a more effective way to find peers by IP */
3281 	RB_FOREACH(p, peer_head, &c->peers)
3282 		if (!p->conf.template &&
3283 		    !memcmp(&addr, &p->conf.remote_addr, sizeof(addr)))
3284 			return (p);
3285 
3286 	/* try template matching */
3287 	RB_FOREACH(p, peer_head, &c->peers)
3288 		if (p->conf.template &&
3289 		    p->conf.remote_addr.aid == addr.aid &&
3290 		    session_match_mask(p, &addr))
3291 			if (loose == NULL || loose->conf.remote_masklen <
3292 			    p->conf.remote_masklen)
3293 				loose = p;
3294 
3295 	if (loose != NULL) {
3296 		/* clone */
3297 		if ((newpeer = malloc(sizeof(struct peer))) == NULL)
3298 			fatal(NULL);
3299 		memcpy(newpeer, loose, sizeof(struct peer));
3300 		for (id = PEER_ID_DYN_MAX; id > PEER_ID_STATIC_MAX; id--) {
3301 			if (getpeerbyid(c, id) == NULL)	/* we found a free id */
3302 				break;
3303 		}
3304 		newpeer->template = loose;
3305 		session_template_clone(newpeer, ip, id, 0);
3306 		newpeer->state = newpeer->prev_state = STATE_NONE;
3307 		newpeer->reconf_action = RECONF_KEEP;
3308 		newpeer->rbuf = NULL;
3309 		newpeer->rpending = 0;
3310 		init_peer(newpeer);
3311 		bgp_fsm(newpeer, EVNT_START);
3312 		if (RB_INSERT(peer_head, &c->peers, newpeer) != NULL)
3313 			fatalx("%s: peer tree is corrupt", __func__);
3314 		return (newpeer);
3315 	}
3316 
3317 	return (NULL);
3318 }
3319 
3320 struct peer *
3321 getpeerbyid(struct bgpd_config *c, uint32_t peerid)
3322 {
3323 	static struct peer lookup;
3324 
3325 	lookup.conf.id = peerid;
3326 
3327 	return RB_FIND(peer_head, &c->peers, &lookup);
3328 }
3329 
3330 int
3331 peer_matched(struct peer *p, struct ctl_neighbor *n)
3332 {
3333 	char *s;
3334 
3335 	if (n && n->addr.aid) {
3336 		if (memcmp(&p->conf.remote_addr, &n->addr,
3337 		    sizeof(p->conf.remote_addr)))
3338 			return 0;
3339 	} else if (n && n->descr[0]) {
3340 		s = n->is_group ? p->conf.group : p->conf.descr;
3341 		if (strcmp(s, n->descr))
3342 			return 0;
3343 	}
3344 	return 1;
3345 }
3346 
3347 void
3348 session_template_clone(struct peer *p, struct sockaddr *ip, uint32_t id,
3349     uint32_t as)
3350 {
3351 	struct bgpd_addr	remote_addr;
3352 
3353 	if (ip)
3354 		sa2addr(ip, &remote_addr, NULL);
3355 	else
3356 		memcpy(&remote_addr, &p->conf.remote_addr, sizeof(remote_addr));
3357 
3358 	memcpy(&p->conf, &p->template->conf, sizeof(struct peer_config));
3359 
3360 	p->conf.id = id;
3361 
3362 	if (as) {
3363 		p->conf.remote_as = as;
3364 		p->conf.ebgp = (p->conf.remote_as != p->conf.local_as);
3365 		if (!p->conf.ebgp)
3366 			/* force enforce_as off for iBGP sessions */
3367 			p->conf.enforce_as = ENFORCE_AS_OFF;
3368 	}
3369 
3370 	memcpy(&p->conf.remote_addr, &remote_addr, sizeof(remote_addr));
3371 	switch (p->conf.remote_addr.aid) {
3372 	case AID_INET:
3373 		p->conf.remote_masklen = 32;
3374 		break;
3375 	case AID_INET6:
3376 		p->conf.remote_masklen = 128;
3377 		break;
3378 	}
3379 	p->conf.template = 0;
3380 }
3381 
3382 int
3383 session_match_mask(struct peer *p, struct bgpd_addr *a)
3384 {
3385 	struct in_addr	 v4masked;
3386 	struct in6_addr	 v6masked;
3387 
3388 	switch (p->conf.remote_addr.aid) {
3389 	case AID_INET:
3390 		inet4applymask(&v4masked, &a->v4, p->conf.remote_masklen);
3391 		if (p->conf.remote_addr.v4.s_addr == v4masked.s_addr)
3392 			return (1);
3393 		return (0);
3394 	case AID_INET6:
3395 		inet6applymask(&v6masked, &a->v6, p->conf.remote_masklen);
3396 
3397 		if (memcmp(&v6masked, &p->conf.remote_addr.v6,
3398 		    sizeof(v6masked)) == 0)
3399 			return (1);
3400 		return (0);
3401 	}
3402 	return (0);
3403 }
3404 
3405 void
3406 session_down(struct peer *peer)
3407 {
3408 	bzero(&peer->capa.neg, sizeof(peer->capa.neg));
3409 	peer->stats.last_updown = getmonotime();
3410 	/*
3411 	 * session_down is called in the exit code path so check
3412 	 * if the RDE is still around, if not there is no need to
3413 	 * send the message.
3414 	 */
3415 	if (ibuf_rde == NULL)
3416 		return;
3417 	if (imsg_rde(IMSG_SESSION_DOWN, peer->conf.id, NULL, 0) == -1)
3418 		fatalx("imsg_compose error");
3419 }
3420 
3421 void
3422 session_up(struct peer *p)
3423 {
3424 	struct session_up	 sup;
3425 
3426 	if (imsg_rde(IMSG_SESSION_ADD, p->conf.id,
3427 	    &p->conf, sizeof(p->conf)) == -1)
3428 		fatalx("imsg_compose error");
3429 
3430 	if (p->local.aid == AID_INET) {
3431 		sup.local_v4_addr = p->local;
3432 		sup.local_v6_addr = p->local_alt;
3433 	} else {
3434 		sup.local_v6_addr = p->local;
3435 		sup.local_v4_addr = p->local_alt;
3436 	}
3437 	sup.remote_addr = p->remote;
3438 
3439 	sup.remote_bgpid = p->remote_bgpid;
3440 	sup.short_as = p->short_as;
3441 	memcpy(&sup.capa, &p->capa.neg, sizeof(sup.capa));
3442 	p->stats.last_updown = getmonotime();
3443 	if (imsg_rde(IMSG_SESSION_UP, p->conf.id, &sup, sizeof(sup)) == -1)
3444 		fatalx("imsg_compose error");
3445 }
3446 
3447 int
3448 imsg_ctl_parent(int type, uint32_t peerid, pid_t pid, void *data,
3449     uint16_t datalen)
3450 {
3451 	return (imsg_compose(ibuf_main, type, peerid, pid, -1, data, datalen));
3452 }
3453 
3454 int
3455 imsg_ctl_rde(int type, pid_t pid, void *data, uint16_t datalen)
3456 {
3457 	if (ibuf_rde_ctl == NULL) {
3458 		log_warnx("Can't send message %u to RDE, ctl pipe closed",
3459 		    type);
3460 		return (0);
3461 	}
3462 	/*
3463 	 * Use control socket to talk to RDE to bypass the queue of the
3464 	 * regular imsg socket.
3465 	 */
3466 	return (imsg_compose(ibuf_rde_ctl, type, 0, pid, -1, data, datalen));
3467 }
3468 
3469 int
3470 imsg_rde(int type, uint32_t peerid, void *data, uint16_t datalen)
3471 {
3472 	if (ibuf_rde == NULL) {
3473 		log_warnx("Can't send message %u to RDE, pipe closed", type);
3474 		return (0);
3475 	}
3476 
3477 	return (imsg_compose(ibuf_rde, type, peerid, 0, -1, data, datalen));
3478 }
3479 
3480 void
3481 session_demote(struct peer *p, int level)
3482 {
3483 	struct demote_msg	msg;
3484 
3485 	strlcpy(msg.demote_group, p->conf.demote_group,
3486 	    sizeof(msg.demote_group));
3487 	msg.level = level;
3488 	if (imsg_compose(ibuf_main, IMSG_DEMOTE, p->conf.id, 0, -1,
3489 	    &msg, sizeof(msg)) == -1)
3490 		fatalx("imsg_compose error");
3491 
3492 	p->demoted += level;
3493 }
3494 
3495 void
3496 session_stop(struct peer *peer, uint8_t subcode)
3497 {
3498 	char data[REASON_LEN];
3499 	size_t datalen;
3500 	size_t reason_len;
3501 	char *communication;
3502 
3503 	datalen = 0;
3504 	communication = peer->conf.reason;
3505 
3506 	if ((subcode == ERR_CEASE_ADMIN_DOWN ||
3507 	    subcode == ERR_CEASE_ADMIN_RESET)
3508 	    && communication && *communication) {
3509 		reason_len = strlen(communication);
3510 		if (reason_len > REASON_LEN - 1) {
3511 		    log_peer_warnx(&peer->conf,
3512 			"trying to send overly long shutdown reason");
3513 		} else {
3514 			data[0] = reason_len;
3515 			datalen = reason_len + sizeof(data[0]);
3516 			memcpy(data + 1, communication, reason_len);
3517 		}
3518 	}
3519 	switch (peer->state) {
3520 	case STATE_OPENSENT:
3521 	case STATE_OPENCONFIRM:
3522 	case STATE_ESTABLISHED:
3523 		session_notification(peer, ERR_CEASE, subcode, data, datalen);
3524 		break;
3525 	default:
3526 		/* session not open, no need to send notification */
3527 		break;
3528 	}
3529 	bgp_fsm(peer, EVNT_STOP);
3530 }
3531 
3532 void
3533 merge_peers(struct bgpd_config *c, struct bgpd_config *nc)
3534 {
3535 	struct peer *p, *np, *next;
3536 
3537 	RB_FOREACH(p, peer_head, &c->peers) {
3538 		/* templates are handled specially */
3539 		if (p->template != NULL)
3540 			continue;
3541 		np = getpeerbyid(nc, p->conf.id);
3542 		if (np == NULL) {
3543 			p->reconf_action = RECONF_DELETE;
3544 			continue;
3545 		}
3546 
3547 		/* peer no longer uses TCP MD5SIG so deconfigure */
3548 		if (p->conf.auth.method == AUTH_MD5SIG &&
3549 		    np->conf.auth.method != AUTH_MD5SIG)
3550 			tcp_md5_del_listener(c, p);
3551 		else if (np->conf.auth.method == AUTH_MD5SIG)
3552 			tcp_md5_add_listener(c, np);
3553 
3554 		memcpy(&p->conf, &np->conf, sizeof(p->conf));
3555 		RB_REMOVE(peer_head, &nc->peers, np);
3556 		free(np);
3557 
3558 		p->reconf_action = RECONF_KEEP;
3559 
3560 		/* had demotion, is demoted, demote removed? */
3561 		if (p->demoted && !p->conf.demote_group[0])
3562 			session_demote(p, -1);
3563 
3564 		/* if session is not open then refresh pfkey data */
3565 		if (p->state < STATE_OPENSENT && !p->template)
3566 			imsg_compose(ibuf_main, IMSG_PFKEY_RELOAD,
3567 			    p->conf.id, 0, -1, NULL, 0);
3568 
3569 		/* sync the RDE in case we keep the peer */
3570 		if (imsg_rde(IMSG_SESSION_ADD, p->conf.id,
3571 		    &p->conf, sizeof(struct peer_config)) == -1)
3572 			fatalx("imsg_compose error");
3573 
3574 		/* apply the config to all clones of a template */
3575 		if (p->conf.template) {
3576 			struct peer *xp;
3577 			RB_FOREACH(xp, peer_head, &c->peers) {
3578 				if (xp->template != p)
3579 					continue;
3580 				session_template_clone(xp, NULL, xp->conf.id,
3581 				    xp->conf.remote_as);
3582 				if (imsg_rde(IMSG_SESSION_ADD, xp->conf.id,
3583 				    &xp->conf, sizeof(xp->conf)) == -1)
3584 					fatalx("imsg_compose error");
3585 			}
3586 		}
3587 	}
3588 
3589 	if (imsg_rde(IMSG_RECONF_DRAIN, 0, NULL, 0) == -1)
3590 		fatalx("imsg_compose error");
3591 
3592 	/* pfkeys of new peers already loaded by the parent process */
3593 	RB_FOREACH_SAFE(np, peer_head, &nc->peers, next) {
3594 		RB_REMOVE(peer_head, &nc->peers, np);
3595 		if (RB_INSERT(peer_head, &c->peers, np) != NULL)
3596 			fatalx("%s: peer tree is corrupt", __func__);
3597 		if (np->conf.auth.method == AUTH_MD5SIG)
3598 			tcp_md5_add_listener(c, np);
3599 	}
3600 }
3601