xref: /openbsd/sbin/unwind/unwind.c (revision e5dd7070)
1 /*	$OpenBSD: unwind.c,v 1.47 2020/05/25 16:52:15 florian Exp $	*/
2 
3 /*
4  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
5  * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
6  * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
7  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
8  *
9  * Permission to use, copy, modify, and distribute this software for any
10  * purpose with or without fee is hereby granted, provided that the above
11  * copyright notice and this permission notice appear in all copies.
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
15  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
19  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20  */
21 #include <sys/types.h>
22 #include <sys/queue.h>
23 #include <sys/socket.h>
24 #include <sys/stat.h>
25 #include <sys/syslog.h>
26 #include <sys/wait.h>
27 
28 #include <net/if.h>
29 #include <net/route.h>
30 
31 #include <err.h>
32 #include <errno.h>
33 #include <event.h>
34 #include <fcntl.h>
35 #include <imsg.h>
36 #include <netdb.h>
37 #include <asr.h>
38 #include <pwd.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <signal.h>
43 #include <unistd.h>
44 
45 #include "log.h"
46 #include "unwind.h"
47 #include "frontend.h"
48 #include "resolver.h"
49 #include "control.h"
50 
51 #define	TRUST_ANCHOR_FILE	"/var/db/unwind.key"
52 
53 __dead void	usage(void);
54 __dead void	main_shutdown(void);
55 
56 void		main_sig_handler(int, short, void *);
57 
58 static pid_t	start_child(int, char *, int, int, int);
59 
60 void		main_dispatch_frontend(int, short, void *);
61 void		main_dispatch_resolver(int, short, void *);
62 
63 static int	main_imsg_send_ipc_sockets(struct imsgbuf *, struct imsgbuf *);
64 static int	main_imsg_send_config(struct uw_conf *);
65 
66 int		main_reload(void);
67 int		main_sendall(enum imsg_type, void *, uint16_t);
68 void		open_ports(void);
69 void		solicit_dns_proposals(void);
70 void		send_blocklist_fd(void);
71 
72 struct uw_conf	*main_conf;
73 struct imsgev	*iev_frontend;
74 struct imsgev	*iev_resolver;
75 char		*conffile;
76 
77 pid_t		 frontend_pid;
78 pid_t		 resolver_pid;
79 
80 uint32_t	 cmd_opts;
81 
82 int		 routesock;
83 
84 void
85 main_sig_handler(int sig, short event, void *arg)
86 {
87 	/*
88 	 * Normal signal handler rules don't apply because libevent
89 	 * decouples for us.
90 	 */
91 
92 	switch (sig) {
93 	case SIGTERM:
94 	case SIGINT:
95 		main_shutdown();
96 		break;
97 	case SIGHUP:
98 		if (main_reload() == -1)
99 			log_warnx("configuration reload failed");
100 		else
101 			log_debug("configuration reloaded");
102 		break;
103 	default:
104 		fatalx("unexpected signal");
105 	}
106 }
107 
108 __dead void
109 usage(void)
110 {
111 	extern char *__progname;
112 
113 	fprintf(stderr, "usage: %s [-dnv] [-f file] [-s socket]\n",
114 	    __progname);
115 	exit(1);
116 }
117 
118 int
119 main(int argc, char *argv[])
120 {
121 	struct event	 ev_sigint, ev_sigterm, ev_sighup;
122 	int		 ch, debug = 0, resolver_flag = 0, frontend_flag = 0;
123 	int		 frontend_routesock, rtfilter;
124 	int		 pipe_main2frontend[2], pipe_main2resolver[2];
125 	int		 control_fd, ta_fd;
126 	char		*csock, *saved_argv0;
127 
128 	csock = UNWIND_SOCKET;
129 
130 	log_init(1, LOG_DAEMON);	/* Log to stderr until daemonized. */
131 	log_setverbose(1);
132 
133 	saved_argv0 = argv[0];
134 	if (saved_argv0 == NULL)
135 		saved_argv0 = "unwind";
136 
137 	while ((ch = getopt(argc, argv, "dEFf:ns:v")) != -1) {
138 		switch (ch) {
139 		case 'd':
140 			debug = 1;
141 			break;
142 		case 'E':
143 			resolver_flag = 1;
144 			break;
145 		case 'F':
146 			frontend_flag = 1;
147 			break;
148 		case 'f':
149 			conffile = optarg;
150 			break;
151 		case 'n':
152 			cmd_opts |= OPT_NOACTION;
153 			break;
154 		case 's':
155 			csock = optarg;
156 			break;
157 		case 'v':
158 			if (cmd_opts & OPT_VERBOSE2)
159 				cmd_opts |= OPT_VERBOSE3;
160 			if (cmd_opts & OPT_VERBOSE)
161 				cmd_opts |= OPT_VERBOSE2;
162 			cmd_opts |= OPT_VERBOSE;
163 			break;
164 		default:
165 			usage();
166 		}
167 	}
168 
169 	argc -= optind;
170 	argv += optind;
171 	if (argc > 0 || (resolver_flag && frontend_flag))
172 		usage();
173 
174 	if (resolver_flag)
175 		resolver(debug, cmd_opts & (OPT_VERBOSE | OPT_VERBOSE2 |
176 		    OPT_VERBOSE3));
177 	else if (frontend_flag)
178 		frontend(debug, cmd_opts & (OPT_VERBOSE | OPT_VERBOSE2 |
179 		    OPT_VERBOSE3));
180 
181 	if ((main_conf = parse_config(conffile)) == NULL)
182 		exit(1);
183 
184 	if (cmd_opts & OPT_NOACTION) {
185 		if (cmd_opts & OPT_VERBOSE)
186 			print_config(main_conf);
187 		else
188 			fprintf(stderr, "configuration OK\n");
189 		exit(0);
190 	}
191 
192 	/* Check for root privileges. */
193 	if (geteuid())
194 		errx(1, "need root privileges");
195 
196 	/* Check for assigned daemon user */
197 	if (getpwnam(UNWIND_USER) == NULL)
198 		errx(1, "unknown user %s", UNWIND_USER);
199 
200 	log_init(debug, LOG_DAEMON);
201 	log_setverbose(cmd_opts & (OPT_VERBOSE | OPT_VERBOSE2 | OPT_VERBOSE3));
202 
203 	if (!debug)
204 		daemon(1, 0);
205 
206 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
207 	    PF_UNSPEC, pipe_main2frontend) == -1)
208 		fatal("main2frontend socketpair");
209 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
210 	    PF_UNSPEC, pipe_main2resolver) == -1)
211 		fatal("main2resolver socketpair");
212 
213 	/* Start children. */
214 	resolver_pid = start_child(PROC_RESOLVER, saved_argv0,
215 	    pipe_main2resolver[1], debug, cmd_opts & (OPT_VERBOSE |
216 	    OPT_VERBOSE2 | OPT_VERBOSE3));
217 	frontend_pid = start_child(PROC_FRONTEND, saved_argv0,
218 	    pipe_main2frontend[1], debug, cmd_opts & (OPT_VERBOSE |
219 	    OPT_VERBOSE2 | OPT_VERBOSE3));
220 
221 	uw_process = PROC_MAIN;
222 	log_procinit(log_procnames[uw_process]);
223 
224 	event_init();
225 
226 	/* Setup signal handler. */
227 	signal_set(&ev_sigint, SIGINT, main_sig_handler, NULL);
228 	signal_set(&ev_sigterm, SIGTERM, main_sig_handler, NULL);
229 	signal_set(&ev_sighup, SIGHUP, main_sig_handler, NULL);
230 	signal_add(&ev_sigint, NULL);
231 	signal_add(&ev_sigterm, NULL);
232 	signal_add(&ev_sighup, NULL);
233 	signal(SIGPIPE, SIG_IGN);
234 
235 	/* Setup pipes to children. */
236 
237 	if ((iev_frontend = malloc(sizeof(struct imsgev))) == NULL ||
238 	    (iev_resolver = malloc(sizeof(struct imsgev))) == NULL)
239 		fatal(NULL);
240 	imsg_init(&iev_frontend->ibuf, pipe_main2frontend[0]);
241 	iev_frontend->handler = main_dispatch_frontend;
242 	imsg_init(&iev_resolver->ibuf, pipe_main2resolver[0]);
243 	iev_resolver->handler = main_dispatch_resolver;
244 
245 	/* Setup event handlers for pipes. */
246 	iev_frontend->events = EV_READ;
247 	event_set(&iev_frontend->ev, iev_frontend->ibuf.fd,
248 	    iev_frontend->events, iev_frontend->handler, iev_frontend);
249 	event_add(&iev_frontend->ev, NULL);
250 
251 	iev_resolver->events = EV_READ;
252 	event_set(&iev_resolver->ev, iev_resolver->ibuf.fd,
253 	    iev_resolver->events, iev_resolver->handler, iev_resolver);
254 	event_add(&iev_resolver->ev, NULL);
255 
256 	if (main_imsg_send_ipc_sockets(&iev_frontend->ibuf,
257 	    &iev_resolver->ibuf))
258 		fatal("could not establish imsg links");
259 
260 	open_ports();
261 
262 	if ((control_fd = control_init(csock)) == -1)
263 		fatalx("control socket setup failed");
264 
265 	if ((frontend_routesock = socket(AF_ROUTE, SOCK_RAW | SOCK_CLOEXEC,
266 	    AF_INET)) == -1)
267 		fatal("route socket");
268 
269 	rtfilter = ROUTE_FILTER(RTM_IFINFO) | ROUTE_FILTER(RTM_PROPOSAL);
270 	if (setsockopt(frontend_routesock, AF_ROUTE, ROUTE_MSGFILTER,
271 	    &rtfilter, sizeof(rtfilter)) == -1)
272 		fatal("setsockopt(ROUTE_MSGFILTER)");
273 
274 	if ((routesock = socket(AF_ROUTE, SOCK_RAW | SOCK_CLOEXEC |
275 	    SOCK_NONBLOCK, AF_INET6)) == -1)
276 		fatal("route socket");
277 	shutdown(SHUT_RD, routesock);
278 
279 	if ((ta_fd = open(TRUST_ANCHOR_FILE, O_RDWR | O_CREAT, 0644)) == -1)
280 		log_warn("%s", TRUST_ANCHOR_FILE);
281 
282 	/* receiver handles failed open correctly */
283 	main_imsg_compose_frontend_fd(IMSG_TAFD, 0, ta_fd);
284 
285 	main_imsg_compose_frontend_fd(IMSG_CONTROLFD, 0, control_fd);
286 	main_imsg_compose_frontend_fd(IMSG_ROUTESOCK, 0, frontend_routesock);
287 	main_imsg_send_config(main_conf);
288 
289 	if (main_conf->blocklist_file != NULL)
290 		send_blocklist_fd();
291 
292 	if (pledge("stdio rpath sendfd", NULL) == -1)
293 		fatal("pledge");
294 
295 	main_imsg_compose_frontend(IMSG_STARTUP, 0, NULL, 0);
296 	main_imsg_compose_resolver(IMSG_STARTUP, 0, NULL, 0);
297 
298 	event_dispatch();
299 
300 	main_shutdown();
301 	return (0);
302 }
303 
304 __dead void
305 main_shutdown(void)
306 {
307 	pid_t	 pid;
308 	int	 status;
309 
310 	/* Close pipes. */
311 	msgbuf_clear(&iev_frontend->ibuf.w);
312 	close(iev_frontend->ibuf.fd);
313 	msgbuf_clear(&iev_resolver->ibuf.w);
314 	close(iev_resolver->ibuf.fd);
315 
316 	config_clear(main_conf);
317 
318 	log_debug("waiting for children to terminate");
319 	do {
320 		pid = wait(&status);
321 		if (pid == -1) {
322 			if (errno != EINTR && errno != ECHILD)
323 				fatal("wait");
324 		} else if (WIFSIGNALED(status))
325 			log_warnx("%s terminated; signal %d",
326 			    (pid == resolver_pid) ? "resolver" :
327 			    "frontend", WTERMSIG(status));
328 	} while (pid != -1 || (pid == -1 && errno == EINTR));
329 
330 	free(iev_frontend);
331 	free(iev_resolver);
332 
333 	log_info("terminating");
334 	exit(0);
335 }
336 
337 static pid_t
338 start_child(int p, char *argv0, int fd, int debug, int verbose)
339 {
340 	char	*argv[7];
341 	int	 argc = 0;
342 	pid_t	 pid;
343 
344 	switch (pid = fork()) {
345 	case -1:
346 		fatal("cannot fork");
347 	case 0:
348 		break;
349 	default:
350 		close(fd);
351 		return (pid);
352 	}
353 
354 	if (fd != 3) {
355 		if (dup2(fd, 3) == -1)
356 			fatal("cannot setup imsg fd");
357 	} else if (fcntl(fd, F_SETFD, 0) == -1)
358 		fatal("cannot setup imsg fd");
359 
360 	argv[argc++] = argv0;
361 	switch (p) {
362 	case PROC_MAIN:
363 		fatalx("Can not start main process");
364 	case PROC_RESOLVER:
365 		argv[argc++] = "-E";
366 		break;
367 	case PROC_FRONTEND:
368 		argv[argc++] = "-F";
369 		break;
370 	}
371 	if (debug)
372 		argv[argc++] = "-d";
373 	if (verbose & OPT_VERBOSE)
374 		argv[argc++] = "-v";
375 	if (verbose & OPT_VERBOSE2)
376 		argv[argc++] = "-v";
377 	if (verbose & OPT_VERBOSE3)
378 		argv[argc++] = "-v";
379 	argv[argc++] = NULL;
380 
381 	execvp(argv0, argv);
382 	fatal("execvp");
383 }
384 
385 void
386 main_dispatch_frontend(int fd, short event, void *bula)
387 {
388 	struct imsgev	*iev = bula;
389 	struct imsgbuf	*ibuf;
390 	struct imsg	 imsg;
391 	ssize_t		 n;
392 	int		 shut = 0, verbose;
393 
394 	ibuf = &iev->ibuf;
395 
396 	if (event & EV_READ) {
397 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
398 			fatal("imsg_read error");
399 		if (n == 0)	/* Connection closed. */
400 			shut = 1;
401 	}
402 	if (event & EV_WRITE) {
403 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
404 			fatal("msgbuf_write");
405 		if (n == 0)	/* Connection closed. */
406 			shut = 1;
407 	}
408 
409 	for (;;) {
410 		if ((n = imsg_get(ibuf, &imsg)) == -1)
411 			fatal("imsg_get");
412 		if (n == 0)	/* No more messages. */
413 			break;
414 
415 		switch (imsg.hdr.type) {
416 		case IMSG_STARTUP_DONE:
417 			solicit_dns_proposals();
418 			break;
419 		case IMSG_CTL_RELOAD:
420 			if (main_reload() == -1)
421 				log_warnx("configuration reload failed");
422 			else
423 				log_warnx("configuration reloaded");
424 			break;
425 		case IMSG_CTL_LOG_VERBOSE:
426 			if (IMSG_DATA_SIZE(imsg) != sizeof(verbose))
427 				fatalx("%s: IMSG_CTL_LOG_VERBOSE wrong length: "
428 				    "%lu", __func__, IMSG_DATA_SIZE(imsg));
429 			memcpy(&verbose, imsg.data, sizeof(verbose));
430 			log_setverbose(verbose);
431 			break;
432 		default:
433 			log_debug("%s: error handling imsg %d", __func__,
434 			    imsg.hdr.type);
435 			break;
436 		}
437 		imsg_free(&imsg);
438 	}
439 	if (!shut)
440 		imsg_event_add(iev);
441 	else {
442 		/* This pipe is dead. Remove its event handler */
443 		event_del(&iev->ev);
444 		event_loopexit(NULL);
445 	}
446 }
447 
448 void
449 main_dispatch_resolver(int fd, short event, void *bula)
450 {
451 	struct imsgev		*iev = bula;
452 	struct imsgbuf		*ibuf;
453 	struct imsg		 imsg;
454 	ssize_t			 n;
455 	int			 shut = 0;
456 
457 	ibuf = &iev->ibuf;
458 
459 	if (event & EV_READ) {
460 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
461 			fatal("imsg_read error");
462 		if (n == 0)	/* Connection closed. */
463 			shut = 1;
464 	}
465 	if (event & EV_WRITE) {
466 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
467 			fatal("msgbuf_write");
468 		if (n == 0)	/* Connection closed. */
469 			shut = 1;
470 	}
471 
472 	for (;;) {
473 		if ((n = imsg_get(ibuf, &imsg)) == -1)
474 			fatal("imsg_get");
475 		if (n == 0)	/* No more messages. */
476 			break;
477 
478 		switch (imsg.hdr.type) {
479 		default:
480 			log_debug("%s: error handling imsg %d", __func__,
481 			    imsg.hdr.type);
482 			break;
483 		}
484 		imsg_free(&imsg);
485 	}
486 	if (!shut)
487 		imsg_event_add(iev);
488 	else {
489 		/* This pipe is dead. Remove its event handler. */
490 		event_del(&iev->ev);
491 		event_loopexit(NULL);
492 	}
493 }
494 
495 void
496 main_imsg_compose_frontend(int type, pid_t pid, void *data, uint16_t datalen)
497 {
498 	if (iev_frontend)
499 		imsg_compose_event(iev_frontend, type, 0, pid, -1, data,
500 		    datalen);
501 }
502 
503 void
504 main_imsg_compose_frontend_fd(int type, pid_t pid, int fd)
505 {
506 	if (iev_frontend)
507 		imsg_compose_event(iev_frontend, type, 0, pid, fd, NULL, 0);
508 }
509 
510 void
511 main_imsg_compose_resolver(int type, pid_t pid, void *data, uint16_t datalen)
512 {
513 	if (iev_resolver)
514 		imsg_compose_event(iev_resolver, type, 0, pid, -1, data,
515 		    datalen);
516 }
517 
518 void
519 imsg_event_add(struct imsgev *iev)
520 {
521 	iev->events = EV_READ;
522 	if (iev->ibuf.w.queued)
523 		iev->events |= EV_WRITE;
524 
525 	event_del(&iev->ev);
526 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev);
527 	event_add(&iev->ev, NULL);
528 }
529 
530 int
531 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
532     pid_t pid, int fd, void *data, uint16_t datalen)
533 {
534 	int	ret;
535 
536 	if ((ret = imsg_compose(&iev->ibuf, type, peerid, pid, fd, data,
537 	    datalen)) != -1)
538 		imsg_event_add(iev);
539 
540 	return (ret);
541 }
542 
543 static int
544 main_imsg_send_ipc_sockets(struct imsgbuf *frontend_buf,
545     struct imsgbuf *resolver_buf)
546 {
547 	int pipe_frontend2resolver[2];
548 
549 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
550 	    PF_UNSPEC, pipe_frontend2resolver) == -1)
551 		return (-1);
552 
553 	if (imsg_compose(frontend_buf, IMSG_SOCKET_IPC_RESOLVER, 0, 0,
554 	    pipe_frontend2resolver[0], NULL, 0) == -1)
555 		return (-1);
556 	if (imsg_compose(resolver_buf, IMSG_SOCKET_IPC_FRONTEND, 0, 0,
557 	    pipe_frontend2resolver[1], NULL, 0) == -1)
558 		return (-1);
559 
560 	return (0);
561 }
562 
563 int
564 main_reload(void)
565 {
566 	struct uw_conf	*xconf;
567 
568 	if ((xconf = parse_config(conffile)) == NULL)
569 		return (-1);
570 
571 	if (main_imsg_send_config(xconf) == -1)
572 		return (-1);
573 
574 	merge_config(main_conf, xconf);
575 
576 	if (main_conf->blocklist_file != NULL)
577 		send_blocklist_fd();
578 
579 	return (0);
580 }
581 
582 int
583 main_imsg_send_config(struct uw_conf *xconf)
584 {
585 	struct uw_forwarder		*uw_forwarder;
586 	struct force_tree_entry	*force_entry;
587 
588 	/* Send fixed part of config to children. */
589 	if (main_sendall(IMSG_RECONF_CONF, xconf, sizeof(*xconf)) == -1)
590 		return (-1);
591 
592 	if (xconf->blocklist_file != NULL) {
593 		if (main_sendall(IMSG_RECONF_BLOCKLIST_FILE,
594 		    xconf->blocklist_file, strlen(xconf->blocklist_file) + 1)
595 		    == -1)
596 			return (-1);
597 	}
598 
599 	/* send static forwarders to children */
600 	TAILQ_FOREACH(uw_forwarder, &xconf->uw_forwarder_list, entry) {
601 		if (main_sendall(IMSG_RECONF_FORWARDER, uw_forwarder,
602 		    sizeof(*uw_forwarder)) == -1)
603 			return (-1);
604 	}
605 
606 	/* send static DoT forwarders to children */
607 	TAILQ_FOREACH(uw_forwarder, &xconf->uw_dot_forwarder_list,
608 	    entry) {
609 		if (main_sendall(IMSG_RECONF_DOT_FORWARDER, uw_forwarder,
610 		    sizeof(*uw_forwarder)) == -1)
611 			return (-1);
612 	}
613 	RB_FOREACH(force_entry, force_tree, &xconf->force) {
614 		if (main_sendall(IMSG_RECONF_FORCE, force_entry,
615 		    sizeof(*force_entry)) == -1)
616 			return (-1);
617 	}
618 
619 	/* Tell children the revised config is now complete. */
620 	if (main_sendall(IMSG_RECONF_END, NULL, 0) == -1)
621 		return (-1);
622 
623 	return (0);
624 }
625 
626 int
627 main_sendall(enum imsg_type type, void *buf, uint16_t len)
628 {
629 	if (imsg_compose_event(iev_frontend, type, 0, 0, -1, buf, len) == -1)
630 		return (-1);
631 	if (imsg_compose_event(iev_resolver, type, 0, 0, -1, buf, len) == -1)
632 		return (-1);
633 	return (0);
634 }
635 
636 void
637 merge_config(struct uw_conf *conf, struct uw_conf *xconf)
638 {
639 	struct uw_forwarder		*uw_forwarder;
640 	struct force_tree_entry	*n, *nxt;
641 
642 	/* Remove & discard existing forwarders. */
643 	while ((uw_forwarder = TAILQ_FIRST(&conf->uw_forwarder_list)) !=
644 	    NULL) {
645 		TAILQ_REMOVE(&conf->uw_forwarder_list, uw_forwarder, entry);
646 		free(uw_forwarder);
647 	}
648 	while ((uw_forwarder = TAILQ_FIRST(&conf->uw_dot_forwarder_list)) !=
649 	    NULL) {
650 		TAILQ_REMOVE(&conf->uw_dot_forwarder_list, uw_forwarder, entry);
651 		free(uw_forwarder);
652 	}
653 
654 	/* Remove & discard existing force tree. */
655 	for (n = RB_MIN(force_tree, &conf->force); n != NULL; n = nxt) {
656 		nxt = RB_NEXT(force_tree, &conf->force, n);
657 		RB_REMOVE(force_tree, &conf->force, n);
658 		free(n);
659 	}
660 
661 	memcpy(&conf->res_pref, &xconf->res_pref,
662 	    sizeof(conf->res_pref));
663 
664 	free(conf->blocklist_file);
665 	conf->blocklist_file = xconf->blocklist_file;
666 	conf->blocklist_log = xconf->blocklist_log;
667 
668 	/* Add new forwarders. */
669 	TAILQ_CONCAT(&conf->uw_forwarder_list, &xconf->uw_forwarder_list,
670 	    entry);
671 	TAILQ_CONCAT(&conf->uw_dot_forwarder_list,
672 	    &xconf->uw_dot_forwarder_list, entry);
673 
674 	for (n = RB_MIN(force_tree, &xconf->force); n != NULL; n = nxt) {
675 		nxt = RB_NEXT(force_tree, &xconf->force, n);
676 		RB_REMOVE(force_tree, &xconf->force, n);
677 		RB_INSERT(force_tree, &conf->force, n);
678 	}
679 
680 	free(xconf);
681 }
682 
683 struct uw_conf *
684 config_new_empty(void)
685 {
686 	static enum uw_resolver_type	 default_res_pref[] = {
687 	    UW_RES_DOT,
688 	    UW_RES_ODOT_FORWARDER,
689 	    UW_RES_FORWARDER,
690 	    UW_RES_RECURSOR,
691 	    UW_RES_ODOT_DHCP,
692 	    UW_RES_DHCP,
693 	    UW_RES_ASR};
694 	struct uw_conf			*xconf;
695 
696 	xconf = calloc(1, sizeof(*xconf));
697 	if (xconf == NULL)
698 		fatal(NULL);
699 
700 	memcpy(&xconf->res_pref.types, &default_res_pref,
701 	    sizeof(default_res_pref));
702 	xconf->res_pref.len = nitems(default_res_pref);
703 
704 	TAILQ_INIT(&xconf->uw_forwarder_list);
705 	TAILQ_INIT(&xconf->uw_dot_forwarder_list);
706 
707 	RB_INIT(&xconf->force);
708 
709 	return (xconf);
710 }
711 
712 void
713 config_clear(struct uw_conf *conf)
714 {
715 	struct uw_conf	*xconf;
716 
717 	/* Merge current config with an empty config. */
718 	xconf = config_new_empty();
719 	merge_config(conf, xconf);
720 
721 	free(conf);
722 }
723 
724 void
725 open_ports(void)
726 {
727 	struct addrinfo	 hints, *res0;
728 	int		 udp4sock = -1, udp6sock = -1, error;
729 
730 	memset(&hints, 0, sizeof(hints));
731 	hints.ai_family = AF_INET;
732 	hints.ai_socktype = SOCK_DGRAM;
733 	hints.ai_flags = AI_NUMERICHOST | AI_PASSIVE;
734 
735 	error = getaddrinfo("127.0.0.1", "domain", &hints, &res0);
736 	if (!error && res0) {
737 		if ((udp4sock = socket(res0->ai_family, res0->ai_socktype,
738 		    res0->ai_protocol)) != -1) {
739 			if (bind(udp4sock, res0->ai_addr, res0->ai_addrlen)
740 			    == -1) {
741 				close(udp4sock);
742 				udp4sock = -1;
743 			}
744 		}
745 	}
746 	if (res0)
747 		freeaddrinfo(res0);
748 
749 	hints.ai_family = AF_INET6;
750 	error = getaddrinfo("::1", "domain", &hints, &res0);
751 	if (!error && res0) {
752 		if ((udp6sock = socket(res0->ai_family, res0->ai_socktype,
753 		    res0->ai_protocol)) != -1) {
754 			if (bind(udp6sock, res0->ai_addr, res0->ai_addrlen)
755 			    == -1) {
756 				close(udp6sock);
757 				udp6sock = -1;
758 			}
759 		}
760 	}
761 	if (res0)
762 		freeaddrinfo(res0);
763 
764 	if (udp4sock == -1 && udp6sock == -1)
765 		fatal("could not bind to 127.0.0.1 or ::1 on port 53");
766 
767 	if (udp4sock != -1)
768 		main_imsg_compose_frontend_fd(IMSG_UDP4SOCK, 0, udp4sock);
769 	if (udp6sock != -1)
770 		main_imsg_compose_frontend_fd(IMSG_UDP6SOCK, 0, udp6sock);
771 }
772 
773 void
774 solicit_dns_proposals(void)
775 {
776 	struct rt_msghdr		 rtm;
777 	struct iovec			 iov[1];
778 	int				 iovcnt = 0;
779 
780 	memset(&rtm, 0, sizeof(rtm));
781 
782 	rtm.rtm_version = RTM_VERSION;
783 	rtm.rtm_type = RTM_PROPOSAL;
784 	rtm.rtm_msglen = sizeof(rtm);
785 	rtm.rtm_tableid = 0;
786 	rtm.rtm_index = 0;
787 	rtm.rtm_seq = arc4random();
788 	rtm.rtm_priority = RTP_PROPOSAL_SOLICIT;
789 
790 	iov[iovcnt].iov_base = &rtm;
791 	iov[iovcnt++].iov_len = sizeof(rtm);
792 
793 	if (writev(routesock, iov, iovcnt) == -1)
794 		log_warn("failed to send solicitation");
795 }
796 
797 void
798 send_blocklist_fd(void)
799 {
800 	int	bl_fd;
801 
802 	if ((bl_fd = open(main_conf->blocklist_file, O_RDONLY)) != -1)
803 		main_imsg_compose_frontend_fd(IMSG_BLFD, 0, bl_fd);
804 	else
805 		log_warn("%s", main_conf->blocklist_file);
806 }
807 
808 void
809 imsg_receive_config(struct imsg *imsg, struct uw_conf **xconf)
810 {
811 	struct uw_conf			*nconf;
812 	struct uw_forwarder		*uw_forwarder;
813 	struct force_tree_entry	*force_entry;
814 
815 	nconf = *xconf;
816 
817 	switch (imsg->hdr.type) {
818 	case IMSG_RECONF_CONF:
819 		if (nconf != NULL)
820 			fatalx("%s: IMSG_RECONF_CONF already in "
821 			    "progress", __func__);
822 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct uw_conf))
823 			fatalx("%s: IMSG_RECONF_CONF wrong length: %lu",
824 			    __func__, IMSG_DATA_SIZE(*imsg));
825 		if ((*xconf = malloc(sizeof(struct uw_conf))) == NULL)
826 			fatal(NULL);
827 		nconf = *xconf;
828 		memcpy(nconf, imsg->data, sizeof(struct uw_conf));
829 		TAILQ_INIT(&nconf->uw_forwarder_list);
830 		TAILQ_INIT(&nconf->uw_dot_forwarder_list);
831 		RB_INIT(&nconf->force);
832 		break;
833 	case IMSG_RECONF_BLOCKLIST_FILE:
834 		/* make sure this is a string */
835 		((char *)imsg->data)[IMSG_DATA_SIZE(*imsg) - 1] = '\0';
836 		if ((nconf->blocklist_file = strdup(imsg->data)) ==
837 		    NULL)
838 			fatal("%s: strdup", __func__);
839 		break;
840 	case IMSG_RECONF_FORWARDER:
841 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct uw_forwarder))
842 			fatalx("%s: IMSG_RECONF_FORWARDER wrong length:"
843 			    " %lu", __func__, IMSG_DATA_SIZE(*imsg));
844 		if ((uw_forwarder = malloc(sizeof(struct
845 		    uw_forwarder))) == NULL)
846 			fatal(NULL);
847 		memcpy(uw_forwarder, imsg->data, sizeof(struct
848 		    uw_forwarder));
849 		TAILQ_INSERT_TAIL(&nconf->uw_forwarder_list,
850 		    uw_forwarder, entry);
851 		break;
852 	case IMSG_RECONF_DOT_FORWARDER:
853 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct uw_forwarder))
854 			fatalx("%s: IMSG_RECONF_DOT_FORWARDER wrong "
855 			    "length: %lu", __func__,
856 			    IMSG_DATA_SIZE(*imsg));
857 		if ((uw_forwarder = malloc(sizeof(struct
858 		    uw_forwarder))) == NULL)
859 			fatal(NULL);
860 		memcpy(uw_forwarder, imsg->data, sizeof(struct
861 		    uw_forwarder));
862 		TAILQ_INSERT_TAIL(&nconf->uw_dot_forwarder_list,
863 		    uw_forwarder, entry);
864 		break;
865 	case IMSG_RECONF_FORCE:
866 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct force_tree_entry))
867 			fatalx("%s: IMSG_RECONF_FORCE wrong "
868 			    "length: %lu", __func__,
869 			    IMSG_DATA_SIZE(*imsg));
870 		if ((force_entry = malloc(sizeof(struct
871 		    force_tree_entry))) == NULL)
872 			fatal(NULL);
873 		memcpy(force_entry, imsg->data, sizeof(struct
874 		    force_tree_entry));
875 		RB_INSERT(force_tree, &nconf->force, force_entry);
876 		break;
877 	default:
878 		log_debug("%s: error handling imsg %d", __func__,
879 		    imsg->hdr.type);
880 		break;
881 	}
882 }
883