xref: /openbsd-src/sbin/unwind/unwind.c (revision f1dd7b858388b4a23f4f67a4957ec5ff656ebbe8)
1 /*	$OpenBSD: unwind.c,v 1.61 2021/02/27 10:32:28 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 enum uw_process {
54 	PROC_MAIN,
55 	PROC_RESOLVER,
56 	PROC_FRONTEND,
57 };
58 
59 __dead void	usage(void);
60 __dead void	main_shutdown(void);
61 
62 void		main_sig_handler(int, short, void *);
63 
64 static pid_t	start_child(enum uw_process, char *, int, int, int);
65 
66 void		main_dispatch_frontend(int, short, void *);
67 void		main_dispatch_resolver(int, short, void *);
68 
69 static int	main_imsg_send_ipc_sockets(struct imsgbuf *, struct imsgbuf *);
70 static int	main_imsg_send_config(struct uw_conf *);
71 
72 int		main_reload(void);
73 int		main_sendall(enum imsg_type, void *, uint16_t);
74 void		open_ports(void);
75 void		solicit_dns_proposals(void);
76 void		send_blocklist_fd(void);
77 
78 struct uw_conf		*main_conf;
79 static struct imsgev	*iev_frontend;
80 static struct imsgev	*iev_resolver;
81 char			*conffile;
82 pid_t			 frontend_pid;
83 pid_t			 resolver_pid;
84 uint32_t		 cmd_opts;
85 int			 routesock;
86 
87 void
88 main_sig_handler(int sig, short event, void *arg)
89 {
90 	/*
91 	 * Normal signal handler rules don't apply because libevent
92 	 * decouples for us.
93 	 */
94 
95 	switch (sig) {
96 	case SIGTERM:
97 	case SIGINT:
98 		main_shutdown();
99 		break;
100 	case SIGHUP:
101 		if (main_reload() == -1)
102 			log_warnx("configuration reload failed");
103 		else
104 			log_debug("configuration reloaded");
105 		break;
106 	default:
107 		fatalx("unexpected signal");
108 	}
109 }
110 
111 __dead void
112 usage(void)
113 {
114 	extern char *__progname;
115 
116 	fprintf(stderr, "usage: %s [-dnv] [-f file] [-s socket]\n",
117 	    __progname);
118 	exit(1);
119 }
120 
121 int
122 main(int argc, char *argv[])
123 {
124 	struct event	 ev_sigint, ev_sigterm, ev_sighup;
125 	int		 ch, debug = 0, resolver_flag = 0, frontend_flag = 0;
126 	int		 frontend_routesock, rtfilter;
127 	int		 pipe_main2frontend[2], pipe_main2resolver[2];
128 	int		 control_fd, ta_fd;
129 	char		*csock, *saved_argv0;
130 
131 	csock = _PATH_UNWIND_SOCKET;
132 
133 	log_init(1, LOG_DAEMON);	/* Log to stderr until daemonized. */
134 	log_setverbose(1);
135 
136 	saved_argv0 = argv[0];
137 	if (saved_argv0 == NULL)
138 		saved_argv0 = "unwind";
139 
140 	while ((ch = getopt(argc, argv, "dEFf:ns:v")) != -1) {
141 		switch (ch) {
142 		case 'd':
143 			debug = 1;
144 			break;
145 		case 'E':
146 			resolver_flag = 1;
147 			break;
148 		case 'F':
149 			frontend_flag = 1;
150 			break;
151 		case 'f':
152 			conffile = optarg;
153 			break;
154 		case 'n':
155 			cmd_opts |= OPT_NOACTION;
156 			break;
157 		case 's':
158 			csock = optarg;
159 			break;
160 		case 'v':
161 			if (cmd_opts & OPT_VERBOSE2)
162 				cmd_opts |= OPT_VERBOSE3;
163 			if (cmd_opts & OPT_VERBOSE)
164 				cmd_opts |= OPT_VERBOSE2;
165 			cmd_opts |= OPT_VERBOSE;
166 			break;
167 		default:
168 			usage();
169 		}
170 	}
171 
172 	argc -= optind;
173 	argv += optind;
174 	if (argc > 0 || (resolver_flag && frontend_flag))
175 		usage();
176 
177 	if (resolver_flag)
178 		resolver(debug, cmd_opts & (OPT_VERBOSE | OPT_VERBOSE2 |
179 		    OPT_VERBOSE3));
180 	else if (frontend_flag)
181 		frontend(debug, cmd_opts & (OPT_VERBOSE | OPT_VERBOSE2 |
182 		    OPT_VERBOSE3));
183 
184 	if ((main_conf = parse_config(conffile)) == NULL)
185 		exit(1);
186 
187 	if (cmd_opts & OPT_NOACTION) {
188 		if (cmd_opts & OPT_VERBOSE)
189 			print_config(main_conf);
190 		else
191 			fprintf(stderr, "configuration OK\n");
192 		exit(0);
193 	}
194 
195 	/* Check for root privileges. */
196 	if (geteuid())
197 		errx(1, "need root privileges");
198 
199 	/* Check for assigned daemon user */
200 	if (getpwnam(UNWIND_USER) == NULL)
201 		errx(1, "unknown user %s", UNWIND_USER);
202 
203 	log_init(debug, LOG_DAEMON);
204 	log_setverbose(cmd_opts & (OPT_VERBOSE | OPT_VERBOSE2 | OPT_VERBOSE3));
205 
206 	if (!debug)
207 		daemon(1, 0);
208 
209 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
210 	    PF_UNSPEC, pipe_main2frontend) == -1)
211 		fatal("main2frontend socketpair");
212 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
213 	    PF_UNSPEC, pipe_main2resolver) == -1)
214 		fatal("main2resolver socketpair");
215 
216 	/* Start children. */
217 	resolver_pid = start_child(PROC_RESOLVER, saved_argv0,
218 	    pipe_main2resolver[1], debug, cmd_opts & (OPT_VERBOSE |
219 	    OPT_VERBOSE2 | OPT_VERBOSE3));
220 	frontend_pid = start_child(PROC_FRONTEND, saved_argv0,
221 	    pipe_main2frontend[1], debug, cmd_opts & (OPT_VERBOSE |
222 	    OPT_VERBOSE2 | OPT_VERBOSE3));
223 
224 	log_procinit("main");
225 
226 	event_init();
227 
228 	/* Setup signal handler. */
229 	signal_set(&ev_sigint, SIGINT, main_sig_handler, NULL);
230 	signal_set(&ev_sigterm, SIGTERM, main_sig_handler, NULL);
231 	signal_set(&ev_sighup, SIGHUP, main_sig_handler, NULL);
232 	signal_add(&ev_sigint, NULL);
233 	signal_add(&ev_sigterm, NULL);
234 	signal_add(&ev_sighup, NULL);
235 	signal(SIGPIPE, SIG_IGN);
236 
237 	/* Setup pipes to children. */
238 
239 	if ((iev_frontend = malloc(sizeof(struct imsgev))) == NULL ||
240 	    (iev_resolver = malloc(sizeof(struct imsgev))) == NULL)
241 		fatal(NULL);
242 	imsg_init(&iev_frontend->ibuf, pipe_main2frontend[0]);
243 	iev_frontend->handler = main_dispatch_frontend;
244 	imsg_init(&iev_resolver->ibuf, pipe_main2resolver[0]);
245 	iev_resolver->handler = main_dispatch_resolver;
246 
247 	/* Setup event handlers for pipes. */
248 	iev_frontend->events = EV_READ;
249 	event_set(&iev_frontend->ev, iev_frontend->ibuf.fd,
250 	    iev_frontend->events, iev_frontend->handler, iev_frontend);
251 	event_add(&iev_frontend->ev, NULL);
252 
253 	iev_resolver->events = EV_READ;
254 	event_set(&iev_resolver->ev, iev_resolver->ibuf.fd,
255 	    iev_resolver->events, iev_resolver->handler, iev_resolver);
256 	event_add(&iev_resolver->ev, NULL);
257 
258 	if (main_imsg_send_ipc_sockets(&iev_frontend->ibuf,
259 	    &iev_resolver->ibuf))
260 		fatal("could not establish imsg links");
261 
262 	open_ports();
263 
264 	if ((control_fd = control_init(csock)) == -1)
265 		fatalx("control socket setup failed");
266 
267 	if ((frontend_routesock = socket(AF_ROUTE, SOCK_RAW | SOCK_CLOEXEC |
268 	    SOCK_NONBLOCK, 0)) == -1)
269 		fatal("route socket");
270 
271 	rtfilter = ROUTE_FILTER(RTM_IFINFO) | ROUTE_FILTER(RTM_PROPOSAL)
272 	    | ROUTE_FILTER(RTM_IFANNOUNCE) | ROUTE_FILTER(RTM_NEWADDR)
273 	    | ROUTE_FILTER(RTM_DELADDR);
274 	if (setsockopt(frontend_routesock, AF_ROUTE, ROUTE_MSGFILTER,
275 	    &rtfilter, sizeof(rtfilter)) == -1)
276 		fatal("setsockopt(ROUTE_MSGFILTER)");
277 
278 	if ((routesock = socket(AF_ROUTE, SOCK_RAW | SOCK_CLOEXEC |
279 	    SOCK_NONBLOCK, 0)) == -1)
280 		fatal("route socket");
281 	shutdown(SHUT_RD, routesock);
282 
283 	if ((ta_fd = open(TRUST_ANCHOR_FILE, O_RDWR | O_CREAT, 0644)) == -1)
284 		log_warn("%s", TRUST_ANCHOR_FILE);
285 
286 	/* receiver handles failed open correctly */
287 	main_imsg_compose_frontend_fd(IMSG_TAFD, 0, ta_fd);
288 
289 	main_imsg_compose_frontend_fd(IMSG_CONTROLFD, 0, control_fd);
290 	main_imsg_compose_frontend_fd(IMSG_ROUTESOCK, 0, frontend_routesock);
291 	main_imsg_send_config(main_conf);
292 
293 	if (main_conf->blocklist_file != NULL)
294 		send_blocklist_fd();
295 
296 	if (pledge("stdio rpath sendfd", NULL) == -1)
297 		fatal("pledge");
298 
299 	main_imsg_compose_frontend(IMSG_STARTUP, 0, NULL, 0);
300 	main_imsg_compose_resolver(IMSG_STARTUP, 0, NULL, 0);
301 
302 	event_dispatch();
303 
304 	main_shutdown();
305 	return (0);
306 }
307 
308 __dead void
309 main_shutdown(void)
310 {
311 	pid_t	 pid;
312 	int	 status;
313 
314 	/* Close pipes. */
315 	msgbuf_clear(&iev_frontend->ibuf.w);
316 	close(iev_frontend->ibuf.fd);
317 	msgbuf_clear(&iev_resolver->ibuf.w);
318 	close(iev_resolver->ibuf.fd);
319 
320 	config_clear(main_conf);
321 
322 	log_debug("waiting for children to terminate");
323 	do {
324 		pid = wait(&status);
325 		if (pid == -1) {
326 			if (errno != EINTR && errno != ECHILD)
327 				fatal("wait");
328 		} else if (WIFSIGNALED(status))
329 			log_warnx("%s terminated; signal %d",
330 			    (pid == resolver_pid) ? "resolver" :
331 			    "frontend", WTERMSIG(status));
332 	} while (pid != -1 || (pid == -1 && errno == EINTR));
333 
334 	free(iev_frontend);
335 	free(iev_resolver);
336 
337 	log_info("terminating");
338 	exit(0);
339 }
340 
341 static pid_t
342 start_child(enum uw_process p, char *argv0, int fd, int debug, int verbose)
343 {
344 	char	*argv[7];
345 	int	 argc = 0;
346 	pid_t	 pid;
347 
348 	switch (pid = fork()) {
349 	case -1:
350 		fatal("cannot fork");
351 	case 0:
352 		break;
353 	default:
354 		close(fd);
355 		return (pid);
356 	}
357 
358 	if (fd != 3) {
359 		if (dup2(fd, 3) == -1)
360 			fatal("cannot setup imsg fd");
361 	} else if (fcntl(fd, F_SETFD, 0) == -1)
362 		fatal("cannot setup imsg fd");
363 
364 	argv[argc++] = argv0;
365 	switch (p) {
366 	case PROC_MAIN:
367 		fatalx("Can not start main process");
368 	case PROC_RESOLVER:
369 		argv[argc++] = "-E";
370 		break;
371 	case PROC_FRONTEND:
372 		argv[argc++] = "-F";
373 		break;
374 	}
375 	if (debug)
376 		argv[argc++] = "-d";
377 	if (verbose & OPT_VERBOSE)
378 		argv[argc++] = "-v";
379 	if (verbose & OPT_VERBOSE2)
380 		argv[argc++] = "-v";
381 	if (verbose & OPT_VERBOSE3)
382 		argv[argc++] = "-v";
383 	argv[argc++] = NULL;
384 
385 	execvp(argv0, argv);
386 	fatal("execvp");
387 }
388 
389 void
390 main_dispatch_frontend(int fd, short event, void *bula)
391 {
392 	struct imsgev	*iev = bula;
393 	struct imsgbuf	*ibuf;
394 	struct imsg	 imsg;
395 	ssize_t		 n;
396 	int		 shut = 0, verbose;
397 
398 	ibuf = &iev->ibuf;
399 
400 	if (event & EV_READ) {
401 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
402 			fatal("imsg_read error");
403 		if (n == 0)	/* Connection closed. */
404 			shut = 1;
405 	}
406 	if (event & EV_WRITE) {
407 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
408 			fatal("msgbuf_write");
409 		if (n == 0)	/* Connection closed. */
410 			shut = 1;
411 	}
412 
413 	for (;;) {
414 		if ((n = imsg_get(ibuf, &imsg)) == -1)
415 			fatal("imsg_get");
416 		if (n == 0)	/* No more messages. */
417 			break;
418 
419 		switch (imsg.hdr.type) {
420 		case IMSG_STARTUP_DONE:
421 			solicit_dns_proposals();
422 			break;
423 		case IMSG_CTL_RELOAD:
424 			if (main_reload() == -1)
425 				log_warnx("configuration reload failed");
426 			else
427 				log_warnx("configuration reloaded");
428 			break;
429 		case IMSG_CTL_LOG_VERBOSE:
430 			if (IMSG_DATA_SIZE(imsg) != sizeof(verbose))
431 				fatalx("%s: IMSG_CTL_LOG_VERBOSE wrong length: "
432 				    "%lu", __func__, IMSG_DATA_SIZE(imsg));
433 			memcpy(&verbose, imsg.data, sizeof(verbose));
434 			log_setverbose(verbose);
435 			break;
436 		default:
437 			log_debug("%s: error handling imsg %d", __func__,
438 			    imsg.hdr.type);
439 			break;
440 		}
441 		imsg_free(&imsg);
442 	}
443 	if (!shut)
444 		imsg_event_add(iev);
445 	else {
446 		/* This pipe is dead. Remove its event handler */
447 		event_del(&iev->ev);
448 		event_loopexit(NULL);
449 	}
450 }
451 
452 void
453 main_dispatch_resolver(int fd, short event, void *bula)
454 {
455 	struct imsgev		*iev = bula;
456 	struct imsgbuf		*ibuf;
457 	struct imsg		 imsg;
458 	ssize_t			 n;
459 	int			 shut = 0;
460 
461 	ibuf = &iev->ibuf;
462 
463 	if (event & EV_READ) {
464 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
465 			fatal("imsg_read error");
466 		if (n == 0)	/* Connection closed. */
467 			shut = 1;
468 	}
469 	if (event & EV_WRITE) {
470 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
471 			fatal("msgbuf_write");
472 		if (n == 0)	/* Connection closed. */
473 			shut = 1;
474 	}
475 
476 	for (;;) {
477 		if ((n = imsg_get(ibuf, &imsg)) == -1)
478 			fatal("imsg_get");
479 		if (n == 0)	/* No more messages. */
480 			break;
481 
482 		switch (imsg.hdr.type) {
483 		default:
484 			log_debug("%s: error handling imsg %d", __func__,
485 			    imsg.hdr.type);
486 			break;
487 		}
488 		imsg_free(&imsg);
489 	}
490 	if (!shut)
491 		imsg_event_add(iev);
492 	else {
493 		/* This pipe is dead. Remove its event handler. */
494 		event_del(&iev->ev);
495 		event_loopexit(NULL);
496 	}
497 }
498 
499 void
500 main_imsg_compose_frontend(int type, pid_t pid, void *data, uint16_t datalen)
501 {
502 	if (iev_frontend)
503 		imsg_compose_event(iev_frontend, type, 0, pid, -1, data,
504 		    datalen);
505 }
506 
507 void
508 main_imsg_compose_frontend_fd(int type, pid_t pid, int fd)
509 {
510 	if (iev_frontend)
511 		imsg_compose_event(iev_frontend, type, 0, pid, fd, NULL, 0);
512 }
513 
514 void
515 main_imsg_compose_resolver(int type, pid_t pid, void *data, uint16_t datalen)
516 {
517 	if (iev_resolver)
518 		imsg_compose_event(iev_resolver, type, 0, pid, -1, data,
519 		    datalen);
520 }
521 
522 void
523 imsg_event_add(struct imsgev *iev)
524 {
525 	iev->events = EV_READ;
526 	if (iev->ibuf.w.queued)
527 		iev->events |= EV_WRITE;
528 
529 	event_del(&iev->ev);
530 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev);
531 	event_add(&iev->ev, NULL);
532 }
533 
534 int
535 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
536     pid_t pid, int fd, void *data, uint16_t datalen)
537 {
538 	int	ret;
539 
540 	if ((ret = imsg_compose(&iev->ibuf, type, peerid, pid, fd, data,
541 	    datalen)) != -1)
542 		imsg_event_add(iev);
543 
544 	return (ret);
545 }
546 
547 static int
548 main_imsg_send_ipc_sockets(struct imsgbuf *frontend_buf,
549     struct imsgbuf *resolver_buf)
550 {
551 	int pipe_frontend2resolver[2];
552 
553 	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
554 	    PF_UNSPEC, pipe_frontend2resolver) == -1)
555 		return (-1);
556 
557 	if (imsg_compose(frontend_buf, IMSG_SOCKET_IPC_RESOLVER, 0, 0,
558 	    pipe_frontend2resolver[0], NULL, 0) == -1)
559 		return (-1);
560 	if (imsg_compose(resolver_buf, IMSG_SOCKET_IPC_FRONTEND, 0, 0,
561 	    pipe_frontend2resolver[1], NULL, 0) == -1)
562 		return (-1);
563 
564 	return (0);
565 }
566 
567 int
568 main_reload(void)
569 {
570 	struct uw_conf	*xconf;
571 
572 	if ((xconf = parse_config(conffile)) == NULL)
573 		return (-1);
574 
575 	if (main_imsg_send_config(xconf) == -1)
576 		return (-1);
577 
578 	merge_config(main_conf, xconf);
579 
580 	if (main_conf->blocklist_file != NULL)
581 		send_blocklist_fd();
582 
583 	return (0);
584 }
585 
586 int
587 main_imsg_send_config(struct uw_conf *xconf)
588 {
589 	struct uw_forwarder		*uw_forwarder;
590 	struct force_tree_entry	*force_entry;
591 
592 	/* Send fixed part of config to children. */
593 	if (main_sendall(IMSG_RECONF_CONF, xconf, sizeof(*xconf)) == -1)
594 		return (-1);
595 
596 	if (xconf->blocklist_file != NULL) {
597 		if (main_sendall(IMSG_RECONF_BLOCKLIST_FILE,
598 		    xconf->blocklist_file, strlen(xconf->blocklist_file) + 1)
599 		    == -1)
600 			return (-1);
601 	}
602 
603 	/* send static forwarders to children */
604 	TAILQ_FOREACH(uw_forwarder, &xconf->uw_forwarder_list, entry) {
605 		if (main_sendall(IMSG_RECONF_FORWARDER, uw_forwarder,
606 		    sizeof(*uw_forwarder)) == -1)
607 			return (-1);
608 	}
609 
610 	/* send static DoT forwarders to children */
611 	TAILQ_FOREACH(uw_forwarder, &xconf->uw_dot_forwarder_list,
612 	    entry) {
613 		if (main_sendall(IMSG_RECONF_DOT_FORWARDER, uw_forwarder,
614 		    sizeof(*uw_forwarder)) == -1)
615 			return (-1);
616 	}
617 	RB_FOREACH(force_entry, force_tree, &xconf->force) {
618 		if (main_sendall(IMSG_RECONF_FORCE, force_entry,
619 		    sizeof(*force_entry)) == -1)
620 			return (-1);
621 	}
622 
623 	/* Tell children the revised config is now complete. */
624 	if (main_sendall(IMSG_RECONF_END, NULL, 0) == -1)
625 		return (-1);
626 
627 	return (0);
628 }
629 
630 int
631 main_sendall(enum imsg_type type, void *buf, uint16_t len)
632 {
633 	if (imsg_compose_event(iev_frontend, type, 0, 0, -1, buf, len) == -1)
634 		return (-1);
635 	if (imsg_compose_event(iev_resolver, type, 0, 0, -1, buf, len) == -1)
636 		return (-1);
637 	return (0);
638 }
639 
640 void
641 merge_config(struct uw_conf *conf, struct uw_conf *xconf)
642 {
643 	struct uw_forwarder		*uw_forwarder;
644 	struct force_tree_entry	*n, *nxt;
645 
646 	/* Remove & discard existing forwarders. */
647 	while ((uw_forwarder = TAILQ_FIRST(&conf->uw_forwarder_list)) !=
648 	    NULL) {
649 		TAILQ_REMOVE(&conf->uw_forwarder_list, uw_forwarder, entry);
650 		free(uw_forwarder);
651 	}
652 	while ((uw_forwarder = TAILQ_FIRST(&conf->uw_dot_forwarder_list)) !=
653 	    NULL) {
654 		TAILQ_REMOVE(&conf->uw_dot_forwarder_list, uw_forwarder, entry);
655 		free(uw_forwarder);
656 	}
657 
658 	/* Remove & discard existing force tree. */
659 	RB_FOREACH_SAFE(n, force_tree, &conf->force, nxt) {
660 		RB_REMOVE(force_tree, &conf->force, n);
661 		free(n);
662 	}
663 
664 	memcpy(&conf->res_pref, &xconf->res_pref,
665 	    sizeof(conf->res_pref));
666 
667 	free(conf->blocklist_file);
668 	conf->blocklist_file = xconf->blocklist_file;
669 	conf->blocklist_log = xconf->blocklist_log;
670 
671 	/* Add new forwarders. */
672 	TAILQ_CONCAT(&conf->uw_forwarder_list, &xconf->uw_forwarder_list,
673 	    entry);
674 	TAILQ_CONCAT(&conf->uw_dot_forwarder_list,
675 	    &xconf->uw_dot_forwarder_list, entry);
676 
677 	RB_FOREACH_SAFE(n, force_tree, &xconf->force, nxt) {
678 		RB_REMOVE(force_tree, &xconf->force, n);
679 		RB_INSERT(force_tree, &conf->force, n);
680 	}
681 
682 	free(xconf);
683 }
684 
685 struct uw_conf *
686 config_new_empty(void)
687 {
688 	static enum uw_resolver_type	 default_res_pref[] = {
689 	    UW_RES_DOT,
690 	    UW_RES_ODOT_FORWARDER,
691 	    UW_RES_FORWARDER,
692 	    UW_RES_RECURSOR,
693 	    UW_RES_ODOT_DHCP,
694 	    UW_RES_DHCP,
695 	    UW_RES_ASR};
696 	struct uw_conf			*xconf;
697 
698 	xconf = calloc(1, sizeof(*xconf));
699 	if (xconf == NULL)
700 		fatal(NULL);
701 
702 	memcpy(&xconf->res_pref.types, &default_res_pref,
703 	    sizeof(default_res_pref));
704 	xconf->res_pref.len = nitems(default_res_pref);
705 
706 	TAILQ_INIT(&xconf->uw_forwarder_list);
707 	TAILQ_INIT(&xconf->uw_dot_forwarder_list);
708 
709 	RB_INIT(&xconf->force);
710 
711 	return (xconf);
712 }
713 
714 void
715 config_clear(struct uw_conf *conf)
716 {
717 	struct uw_conf	*xconf;
718 
719 	/* Merge current config with an empty config. */
720 	xconf = config_new_empty();
721 	merge_config(conf, xconf);
722 
723 	free(conf);
724 }
725 
726 void
727 open_ports(void)
728 {
729 	struct addrinfo	 hints, *res0;
730 	int		 udp4sock = -1, udp6sock = -1, error, bsize = 65535;
731 	int		 tcp4sock = -1, tcp6sock = -1;
732 	int		 opt = 1;
733 
734 	memset(&hints, 0, sizeof(hints));
735 	hints.ai_family = AF_INET;
736 	hints.ai_socktype = SOCK_DGRAM;
737 	hints.ai_flags = AI_NUMERICHOST | AI_PASSIVE;
738 
739 	error = getaddrinfo("127.0.0.1", "domain", &hints, &res0);
740 	if (!error && res0) {
741 		if ((udp4sock = socket(res0->ai_family, res0->ai_socktype,
742 		    res0->ai_protocol)) != -1) {
743 			if (setsockopt(udp4sock, SOL_SOCKET, SO_REUSEADDR,
744 			    &opt, sizeof(opt)) == -1)
745 				log_warn("setting SO_REUSEADDR on socket");
746 			if (setsockopt(udp4sock, SOL_SOCKET, SO_SNDBUF, &bsize,
747 			    sizeof(bsize)) == -1)
748 				log_warn("setting SO_SNDBUF on socket");
749 			if (bind(udp4sock, res0->ai_addr, res0->ai_addrlen)
750 			    == -1) {
751 				close(udp4sock);
752 				udp4sock = -1;
753 			}
754 		}
755 	}
756 	if (res0)
757 		freeaddrinfo(res0);
758 
759 	hints.ai_family = AF_INET6;
760 	error = getaddrinfo("::1", "domain", &hints, &res0);
761 	if (!error && res0) {
762 		if ((udp6sock = socket(res0->ai_family, res0->ai_socktype,
763 		    res0->ai_protocol)) != -1) {
764 			if (setsockopt(udp6sock, SOL_SOCKET, SO_REUSEADDR,
765 			    &opt, sizeof(opt)) == -1)
766 				log_warn("setting SO_REUSEADDR on socket");
767 			if (setsockopt(udp6sock, SOL_SOCKET, SO_SNDBUF, &bsize,
768 			    sizeof(bsize)) == -1)
769 				log_warn("setting SO_SNDBUF on socket");
770 			if (bind(udp6sock, res0->ai_addr, res0->ai_addrlen)
771 			    == -1) {
772 				close(udp6sock);
773 				udp6sock = -1;
774 			}
775 		}
776 	}
777 	if (res0)
778 		freeaddrinfo(res0);
779 
780 	hints.ai_family = AF_INET;
781 	hints.ai_socktype = SOCK_STREAM;
782 
783 	error = getaddrinfo("127.0.0.1", "domain", &hints, &res0);
784 	if (!error && res0) {
785 		if ((tcp4sock = socket(res0->ai_family,
786 		    res0->ai_socktype | SOCK_NONBLOCK,
787 		    res0->ai_protocol)) != -1) {
788 			if (setsockopt(tcp4sock, SOL_SOCKET, SO_REUSEADDR,
789 			    &opt, sizeof(opt)) == -1)
790 				log_warn("setting SO_REUSEADDR on socket");
791 			if (setsockopt(tcp4sock, SOL_SOCKET, SO_SNDBUF, &bsize,
792 			    sizeof(bsize)) == -1)
793 				log_warn("setting SO_SNDBUF on socket");
794 			if (bind(tcp4sock, res0->ai_addr, res0->ai_addrlen)
795 			    == -1) {
796 				close(tcp4sock);
797 				tcp4sock = -1;
798 			}
799 			if (listen(tcp4sock, 5) == -1) {
800 				close(tcp4sock);
801 				tcp4sock = -1;
802 			}
803 		}
804 	}
805 	if (res0)
806 		freeaddrinfo(res0);
807 
808 	hints.ai_family = AF_INET6;
809 	error = getaddrinfo("::1", "domain", &hints, &res0);
810 	if (!error && res0) {
811 		if ((tcp6sock = socket(res0->ai_family,
812 		    res0->ai_socktype | SOCK_NONBLOCK,
813 		    res0->ai_protocol)) != -1) {
814 			if (setsockopt(tcp6sock, SOL_SOCKET, SO_REUSEADDR,
815 			    &opt, sizeof(opt)) == -1)
816 				log_warn("setting SO_REUSEADDR on socket");
817 			if (setsockopt(tcp6sock, SOL_SOCKET, SO_SNDBUF, &bsize,
818 			    sizeof(bsize)) == -1)
819 				log_warn("setting SO_SNDBUF on socket");
820 			if (bind(tcp6sock, res0->ai_addr, res0->ai_addrlen)
821 			    == -1) {
822 				close(tcp6sock);
823 				tcp6sock = -1;
824 			}
825 			if (listen(tcp6sock, 5) == -1) {
826 				close(tcp6sock);
827 				tcp6sock = -1;
828 			}
829 		}
830 	}
831 	if (res0)
832 		freeaddrinfo(res0);
833 
834 	if ((udp4sock == -1 || tcp4sock == -1) && (udp6sock == -1 ||
835 	    tcp6sock == -1))
836 		fatalx("could not bind to 127.0.0.1 or ::1 on port 53");
837 
838 	if (udp4sock != -1)
839 		main_imsg_compose_frontend_fd(IMSG_UDP4SOCK, 0, udp4sock);
840 	if (udp6sock != -1)
841 		main_imsg_compose_frontend_fd(IMSG_UDP6SOCK, 0, udp6sock);
842 	if (tcp4sock != -1)
843 		main_imsg_compose_frontend_fd(IMSG_TCP4SOCK, 0, tcp4sock);
844 	if (tcp6sock != -1)
845 		main_imsg_compose_frontend_fd(IMSG_TCP6SOCK, 0, tcp6sock);
846 }
847 
848 void
849 solicit_dns_proposals(void)
850 {
851 	struct rt_msghdr		 rtm;
852 	struct iovec			 iov[1];
853 	int				 iovcnt = 0;
854 
855 	memset(&rtm, 0, sizeof(rtm));
856 
857 	rtm.rtm_version = RTM_VERSION;
858 	rtm.rtm_type = RTM_PROPOSAL;
859 	rtm.rtm_msglen = sizeof(rtm);
860 	rtm.rtm_tableid = 0;
861 	rtm.rtm_index = 0;
862 	rtm.rtm_seq = arc4random();
863 	rtm.rtm_priority = RTP_PROPOSAL_SOLICIT;
864 
865 	iov[iovcnt].iov_base = &rtm;
866 	iov[iovcnt++].iov_len = sizeof(rtm);
867 
868 	if (writev(routesock, iov, iovcnt) == -1)
869 		log_warn("failed to send solicitation");
870 }
871 
872 void
873 send_blocklist_fd(void)
874 {
875 	int	bl_fd;
876 
877 	if ((bl_fd = open(main_conf->blocklist_file, O_RDONLY)) != -1)
878 		main_imsg_compose_frontend_fd(IMSG_BLFD, 0, bl_fd);
879 	else
880 		log_warn("%s", main_conf->blocklist_file);
881 }
882 
883 void
884 imsg_receive_config(struct imsg *imsg, struct uw_conf **xconf)
885 {
886 	struct uw_conf			*nconf;
887 	struct uw_forwarder		*uw_forwarder;
888 	struct force_tree_entry	*force_entry;
889 
890 	nconf = *xconf;
891 
892 	switch (imsg->hdr.type) {
893 	case IMSG_RECONF_CONF:
894 		if (nconf != NULL)
895 			fatalx("%s: IMSG_RECONF_CONF already in "
896 			    "progress", __func__);
897 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct uw_conf))
898 			fatalx("%s: IMSG_RECONF_CONF wrong length: %lu",
899 			    __func__, IMSG_DATA_SIZE(*imsg));
900 		if ((*xconf = malloc(sizeof(struct uw_conf))) == NULL)
901 			fatal(NULL);
902 		nconf = *xconf;
903 		memcpy(nconf, imsg->data, sizeof(struct uw_conf));
904 		TAILQ_INIT(&nconf->uw_forwarder_list);
905 		TAILQ_INIT(&nconf->uw_dot_forwarder_list);
906 		RB_INIT(&nconf->force);
907 		break;
908 	case IMSG_RECONF_BLOCKLIST_FILE:
909 		/* make sure this is a string */
910 		((char *)imsg->data)[IMSG_DATA_SIZE(*imsg) - 1] = '\0';
911 		if ((nconf->blocklist_file = strdup(imsg->data)) ==
912 		    NULL)
913 			fatal("%s: strdup", __func__);
914 		break;
915 	case IMSG_RECONF_FORWARDER:
916 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct uw_forwarder))
917 			fatalx("%s: IMSG_RECONF_FORWARDER wrong length:"
918 			    " %lu", __func__, IMSG_DATA_SIZE(*imsg));
919 		if ((uw_forwarder = malloc(sizeof(struct
920 		    uw_forwarder))) == NULL)
921 			fatal(NULL);
922 		memcpy(uw_forwarder, imsg->data, sizeof(struct
923 		    uw_forwarder));
924 		TAILQ_INSERT_TAIL(&nconf->uw_forwarder_list,
925 		    uw_forwarder, entry);
926 		break;
927 	case IMSG_RECONF_DOT_FORWARDER:
928 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct uw_forwarder))
929 			fatalx("%s: IMSG_RECONF_DOT_FORWARDER wrong "
930 			    "length: %lu", __func__,
931 			    IMSG_DATA_SIZE(*imsg));
932 		if ((uw_forwarder = malloc(sizeof(struct
933 		    uw_forwarder))) == NULL)
934 			fatal(NULL);
935 		memcpy(uw_forwarder, imsg->data, sizeof(struct
936 		    uw_forwarder));
937 		TAILQ_INSERT_TAIL(&nconf->uw_dot_forwarder_list,
938 		    uw_forwarder, entry);
939 		break;
940 	case IMSG_RECONF_FORCE:
941 		if (IMSG_DATA_SIZE(*imsg) != sizeof(struct force_tree_entry))
942 			fatalx("%s: IMSG_RECONF_FORCE wrong "
943 			    "length: %lu", __func__,
944 			    IMSG_DATA_SIZE(*imsg));
945 		if ((force_entry = malloc(sizeof(struct
946 		    force_tree_entry))) == NULL)
947 			fatal(NULL);
948 		memcpy(force_entry, imsg->data, sizeof(struct
949 		    force_tree_entry));
950 		if (RB_INSERT(force_tree, &nconf->force, force_entry) != NULL) {
951 			free(force_entry);
952 			fatalx("%s: IMSG_RECONF_FORCE duplicate entry",
953 			    __func__);
954 		}
955 		break;
956 	default:
957 		log_debug("%s: error handling imsg %d", __func__,
958 		    imsg->hdr.type);
959 		break;
960 	}
961 }
962