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IABSD.fr/src/usr.sbin/rad/rad.c

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  • Author : florian
    Date : 2021-02-27 10:35:20
    Hash : e0daf9a7
    Message : Path #defines are traditionally prefixed with _PATH. Pointed out by deraadt

  • usr.sbin/rad/rad.c
  • /*	$OpenBSD: rad.c,v 1.27 2021/02/27 10:35:20 florian Exp $	*/
    
    /*
     * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
     * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
     * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
     * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
     *
     * Permission to use, copy, modify, and distribute this software for any
     * purpose with or without fee is hereby granted, provided that the above
     * copyright notice and this permission notice appear in all copies.
     *
     * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     */
    #include <sys/types.h>
    #include <sys/queue.h>
    #include <sys/socket.h>
    #include <sys/syslog.h>
    #include <sys/uio.h>
    #include <sys/wait.h>
    
    #include <netinet/in.h>
    #include <net/if.h>
    #include <net/route.h>
    #include <netinet/in.h>
    #include <netinet/if_ether.h>
    #include <netinet6/in6_var.h>
    #include <netinet/icmp6.h>
    
    #include <err.h>
    #include <errno.h>
    #include <event.h>
    #include <fcntl.h>
    #include <imsg.h>
    #include <netdb.h>
    #include <pwd.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <signal.h>
    #include <unistd.h>
    
    #include "log.h"
    #include "rad.h"
    #include "frontend.h"
    #include "engine.h"
    #include "control.h"
    
    enum rad_process {
    	PROC_MAIN,
    	PROC_ENGINE,
    	PROC_FRONTEND
    };
    
    __dead void	usage(void);
    __dead void	main_shutdown(void);
    
    void	main_sig_handler(int, short, void *);
    
    static pid_t	start_child(enum rad_process, char *, int, int, int);
    
    void	main_dispatch_frontend(int, short, void *);
    void	main_dispatch_engine(int, short, void *);
    void	open_icmp6sock(int);
    
    static int	main_imsg_send_ipc_sockets(struct imsgbuf *, struct imsgbuf *);
    static int	main_imsg_send_config(struct rad_conf *);
    
    int	main_reload(void);
    int	main_sendboth(enum imsg_type, void *, uint16_t);
    
    void	in6_prefixlen2mask(struct in6_addr *, int len);
    
    struct rad_conf		*main_conf;
    static struct imsgev	*iev_frontend;
    static struct imsgev	*iev_engine;
    char			*conffile;
    pid_t			 frontend_pid;
    pid_t			 engine_pid;
    uint32_t		 cmd_opts;
    
    void
    main_sig_handler(int sig, short event, void *arg)
    {
    	/*
    	 * Normal signal handler rules don't apply because libevent
    	 * decouples for us.
    	 */
    
    	switch (sig) {
    	case SIGTERM:
    	case SIGINT:
    		main_shutdown();
    		break;
    	case SIGHUP:
    		if (main_reload() == -1)
    			log_warnx("configuration reload failed");
    		else
    			log_debug("configuration reloaded");
    		break;
    	default:
    		fatalx("unexpected signal");
    	}
    }
    
    __dead void
    usage(void)
    {
    	extern char *__progname;
    
    	fprintf(stderr, "usage: %s [-dnv] [-f file] [-s socket]\n",
    	    __progname);
    	exit(1);
    }
    
    int
    main(int argc, char *argv[])
    {
    	struct event		 ev_sigint, ev_sigterm, ev_sighup;
    	int			 ch;
    	int			 debug = 0, engine_flag = 0, frontend_flag = 0;
    	char			*saved_argv0;
    	int			 pipe_main2frontend[2];
    	int			 pipe_main2engine[2];
    	int			 frontend_routesock, rtfilter;
    	int			 rtable_any = RTABLE_ANY;
    	int			 control_fd;
    	char			*csock;
    
    	conffile = _PATH_CONF_FILE;
    	csock = _PATH_RAD_SOCKET;
    
    	log_init(1, LOG_DAEMON);	/* Log to stderr until daemonized. */
    	log_setverbose(1);
    
    	saved_argv0 = argv[0];
    	if (saved_argv0 == NULL)
    		saved_argv0 = "rad";
    
    	while ((ch = getopt(argc, argv, "dEFf:ns:v")) != -1) {
    		switch (ch) {
    		case 'd':
    			debug = 1;
    			break;
    		case 'E':
    			engine_flag = 1;
    			break;
    		case 'F':
    			frontend_flag = 1;
    			break;
    		case 'f':
    			conffile = optarg;
    			break;
    		case 'n':
    			cmd_opts |= OPT_NOACTION;
    			break;
    		case 's':
    			csock = optarg;
    			break;
    		case 'v':
    			if (cmd_opts & OPT_VERBOSE)
    				cmd_opts |= OPT_VERBOSE2;
    			cmd_opts |= OPT_VERBOSE;
    			break;
    		default:
    			usage();
    		}
    	}
    
    	argc -= optind;
    	argv += optind;
    	if (argc > 0 || (engine_flag && frontend_flag))
    		usage();
    
    	if (engine_flag)
    		engine(debug, cmd_opts & OPT_VERBOSE);
    	else if (frontend_flag)
    		frontend(debug, cmd_opts & OPT_VERBOSE);
    
    	/* parse config file */
    	if ((main_conf = parse_config(conffile)) == NULL) {
    		exit(1);
    	}
    
    	if (cmd_opts & OPT_NOACTION) {
    		if (cmd_opts & OPT_VERBOSE)
    			print_config(main_conf);
    		else
    			fprintf(stderr, "configuration OK\n");
    		exit(0);
    	}
    
    	/* Check for root privileges. */
    	if (geteuid())
    		errx(1, "need root privileges");
    
    	/* Check for assigned daemon user */
    	if (getpwnam(RAD_USER) == NULL)
    		errx(1, "unknown user %s", RAD_USER);
    
    	log_init(debug, LOG_DAEMON);
    	log_setverbose(cmd_opts & OPT_VERBOSE);
    
    	if (!debug)
    		daemon(1, 0);
    
    	log_info("startup");
    
    	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
    	    PF_UNSPEC, pipe_main2frontend) == -1)
    		fatal("main2frontend socketpair");
    	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
    	    PF_UNSPEC, pipe_main2engine) == -1)
    		fatal("main2engine socketpair");
    
    	/* Start children. */
    	engine_pid = start_child(PROC_ENGINE, saved_argv0, pipe_main2engine[1],
    	    debug, cmd_opts & OPT_VERBOSE);
    	frontend_pid = start_child(PROC_FRONTEND, saved_argv0,
    	    pipe_main2frontend[1], debug, cmd_opts & OPT_VERBOSE);
    
    	log_procinit("main");
    
    	event_init();
    
    	/* Setup signal handler. */
    	signal_set(&ev_sigint, SIGINT, main_sig_handler, NULL);
    	signal_set(&ev_sigterm, SIGTERM, main_sig_handler, NULL);
    	signal_set(&ev_sighup, SIGHUP, main_sig_handler, NULL);
    	signal_add(&ev_sigint, NULL);
    	signal_add(&ev_sigterm, NULL);
    	signal_add(&ev_sighup, NULL);
    	signal(SIGPIPE, SIG_IGN);
    
    	/* Setup pipes to children. */
    
    	if ((iev_frontend = malloc(sizeof(struct imsgev))) == NULL ||
    	    (iev_engine = malloc(sizeof(struct imsgev))) == NULL)
    		fatal(NULL);
    	imsg_init(&iev_frontend->ibuf, pipe_main2frontend[0]);
    	iev_frontend->handler = main_dispatch_frontend;
    	imsg_init(&iev_engine->ibuf, pipe_main2engine[0]);
    	iev_engine->handler = main_dispatch_engine;
    
    	/* Setup event handlers for pipes to engine & frontend. */
    	iev_frontend->events = EV_READ;
    	event_set(&iev_frontend->ev, iev_frontend->ibuf.fd,
    	    iev_frontend->events, iev_frontend->handler, iev_frontend);
    	event_add(&iev_frontend->ev, NULL);
    
    	iev_engine->events = EV_READ;
    	event_set(&iev_engine->ev, iev_engine->ibuf.fd, iev_engine->events,
    	    iev_engine->handler, iev_engine);
    	event_add(&iev_engine->ev, NULL);
    
    	if (main_imsg_send_ipc_sockets(&iev_frontend->ibuf, &iev_engine->ibuf))
    		fatal("could not establish imsg links");
    
    	if ((frontend_routesock = socket(AF_ROUTE, SOCK_RAW | SOCK_CLOEXEC,
    	    AF_INET6)) == -1)
    		fatal("route socket");
    
    	rtfilter = ROUTE_FILTER(RTM_IFINFO) | ROUTE_FILTER(RTM_NEWADDR) |
    	    ROUTE_FILTER(RTM_DELADDR) | ROUTE_FILTER(RTM_CHGADDRATTR);
    	if (setsockopt(frontend_routesock, AF_ROUTE, ROUTE_MSGFILTER,
    	    &rtfilter, sizeof(rtfilter)) == -1)
    		fatal("setsockopt(ROUTE_MSGFILTER)");
    	if (setsockopt(frontend_routesock, AF_ROUTE, ROUTE_TABLEFILTER,
    	    &rtable_any, sizeof(rtable_any)) == -1)
    		fatal("setsockopt(ROUTE_TABLEFILTER)");
    
    	if ((control_fd = control_init(csock)) == -1)
    		fatalx("control socket setup failed");
    
    	main_imsg_compose_frontend(IMSG_ROUTESOCK, frontend_routesock,
    	    NULL, 0);
    	main_imsg_compose_frontend(IMSG_CONTROLFD, control_fd, NULL, 0);
    	main_imsg_send_config(main_conf);
    
    	if (pledge("stdio inet rpath sendfd mcast wroute", NULL) == -1)
    		fatal("pledge");
    
    	main_imsg_compose_frontend(IMSG_STARTUP, -1, NULL, 0);
    
    	event_dispatch();
    
    	main_shutdown();
    	return (0);
    }
    
    __dead void
    main_shutdown(void)
    {
    	pid_t	 pid;
    	int	 status;
    
    	/* Close pipes. */
    	msgbuf_clear(&iev_frontend->ibuf.w);
    	close(iev_frontend->ibuf.fd);
    	msgbuf_clear(&iev_engine->ibuf.w);
    	close(iev_engine->ibuf.fd);
    
    	config_clear(main_conf);
    
    	log_debug("waiting for children to terminate");
    	do {
    		pid = wait(&status);
    		if (pid == -1) {
    			if (errno != EINTR && errno != ECHILD)
    				fatal("wait");
    		} else if (WIFSIGNALED(status))
    			log_warnx("%s terminated; signal %d",
    			    (pid == engine_pid) ? "engine" :
    			    "frontend", WTERMSIG(status));
    	} while (pid != -1 || (pid == -1 && errno == EINTR));
    
    	free(iev_frontend);
    	free(iev_engine);
    
    	log_info("terminating");
    	exit(0);
    }
    
    static pid_t
    start_child(enum rad_process p, char *argv0, int fd, int debug, int verbose)
    {
    	char	*argv[6];
    	int	 argc = 0;
    	pid_t	 pid;
    
    	switch (pid = fork()) {
    	case -1:
    		fatal("cannot fork");
    	case 0:
    		break;
    	default:
    		close(fd);
    		return (pid);
    	}
    
    	if (fd != 3) {
    		if (dup2(fd, 3) == -1)
    			fatal("cannot setup imsg fd");
    	} else if (fcntl(fd, F_SETFD, 0) == -1)
    		fatal("cannot setup imsg fd");
    
    	argv[argc++] = argv0;
    	switch (p) {
    	case PROC_MAIN:
    		fatalx("Can not start main process");
    	case PROC_ENGINE:
    		argv[argc++] = "-E";
    		break;
    	case PROC_FRONTEND:
    		argv[argc++] = "-F";
    		break;
    	}
    	if (debug)
    		argv[argc++] = "-d";
    	if (verbose)
    		argv[argc++] = "-v";
    	argv[argc++] = NULL;
    
    	execvp(argv0, argv);
    	fatal("execvp");
    }
    
    void
    main_dispatch_frontend(int fd, short event, void *bula)
    {
    	struct imsgev		*iev = bula;
    	struct imsgbuf		*ibuf;
    	struct imsg		 imsg;
    	ssize_t			 n;
    	int			 shut = 0, verbose;
    	int			 rdomain;
    
    	ibuf = &iev->ibuf;
    
    	if (event & EV_READ) {
    		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
    			fatal("imsg_read error");
    		if (n == 0)	/* Connection closed. */
    			shut = 1;
    	}
    	if (event & EV_WRITE) {
    		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
    			fatal("msgbuf_write");
    		if (n == 0)	/* Connection closed. */
    			shut = 1;
    	}
    
    	for (;;) {
    		if ((n = imsg_get(ibuf, &imsg)) == -1)
    			fatal("imsg_get");
    		if (n == 0)	/* No more messages. */
    			break;
    
    		switch (imsg.hdr.type) {
    		case IMSG_OPEN_ICMP6SOCK:
    			log_debug("IMSG_OPEN_ICMP6SOCK");
    			if (IMSG_DATA_SIZE(imsg) != sizeof(rdomain))
    				fatalx("%s: IMSG_OPEN_ICMP6SOCK wrong length: "
    				    "%lu", __func__, IMSG_DATA_SIZE(imsg));
    			memcpy(&rdomain, imsg.data, sizeof(rdomain));
    			open_icmp6sock(rdomain);
    			break;
    		case IMSG_CTL_RELOAD:
    			if (main_reload() == -1)
    				log_warnx("configuration reload failed");
    			else
    				log_warnx("configuration reloaded");
    			break;
    		case IMSG_CTL_LOG_VERBOSE:
    			if (IMSG_DATA_SIZE(imsg) != sizeof(verbose))
    				fatalx("%s: IMSG_CTL_LOG_VERBOSE wrong length: "
    				    "%lu", __func__, IMSG_DATA_SIZE(imsg));
    			memcpy(&verbose, imsg.data, sizeof(verbose));
    			log_setverbose(verbose);
    			break;
    		default:
    			log_debug("%s: error handling imsg %d", __func__,
    			    imsg.hdr.type);
    			break;
    		}
    		imsg_free(&imsg);
    	}
    	if (!shut)
    		imsg_event_add(iev);
    	else {
    		/* This pipe is dead. Remove its event handler */
    		event_del(&iev->ev);
    		event_loopexit(NULL);
    	}
    }
    
    void
    main_dispatch_engine(int fd, short event, void *bula)
    {
    	struct imsgev	*iev = bula;
    	struct imsgbuf  *ibuf;
    	struct imsg	 imsg;
    	ssize_t		 n;
    	int		 shut = 0;
    
    	ibuf = &iev->ibuf;
    
    	if (event & EV_READ) {
    		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
    			fatal("imsg_read error");
    		if (n == 0)	/* Connection closed. */
    			shut = 1;
    	}
    	if (event & EV_WRITE) {
    		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
    			fatal("msgbuf_write");
    		if (n == 0)	/* Connection closed. */
    			shut = 1;
    	}
    
    	for (;;) {
    		if ((n = imsg_get(ibuf, &imsg)) == -1)
    			fatal("imsg_get");
    		if (n == 0)	/* No more messages. */
    			break;
    
    		switch (imsg.hdr.type) {
    		default:
    			log_debug("%s: error handling imsg %d", __func__,
    			    imsg.hdr.type);
    			break;
    		}
    		imsg_free(&imsg);
    	}
    	if (!shut)
    		imsg_event_add(iev);
    	else {
    		/* This pipe is dead. Remove its event handler. */
    		event_del(&iev->ev);
    		event_loopexit(NULL);
    	}
    }
    
    int
    main_imsg_compose_frontend(int type, int fd, void *data, uint16_t datalen)
    {
    	if (iev_frontend)
    		return (imsg_compose_event(iev_frontend, type, 0, 0, fd, data,
    		    datalen));
    	else
    		return (-1);
    }
    
    void
    main_imsg_compose_engine(int type, pid_t pid, void *data, uint16_t datalen)
    {
    	if (iev_engine)
    		imsg_compose_event(iev_engine, type, 0, pid, -1, data,
    		    datalen);
    }
    
    void
    imsg_event_add(struct imsgev *iev)
    {
    	iev->events = EV_READ;
    	if (iev->ibuf.w.queued)
    		iev->events |= EV_WRITE;
    
    	event_del(&iev->ev);
    	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev);
    	event_add(&iev->ev, NULL);
    }
    
    int
    imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
        pid_t pid, int fd, void *data, uint16_t datalen)
    {
    	int	ret;
    
    	if ((ret = imsg_compose(&iev->ibuf, type, peerid, pid, fd, data,
    	    datalen)) != -1)
    		imsg_event_add(iev);
    
    	return (ret);
    }
    
    static int
    main_imsg_send_ipc_sockets(struct imsgbuf *frontend_buf,
        struct imsgbuf *engine_buf)
    {
    	int pipe_frontend2engine[2];
    
    	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
    	    PF_UNSPEC, pipe_frontend2engine) == -1)
    		return (-1);
    
    	if (imsg_compose(frontend_buf, IMSG_SOCKET_IPC, 0, 0,
    	    pipe_frontend2engine[0], NULL, 0) == -1)
    		return (-1);
    	if (imsg_compose(engine_buf, IMSG_SOCKET_IPC, 0, 0,
    	    pipe_frontend2engine[1], NULL, 0) == -1)
    		return (-1);
    
    	return (0);
    }
    
    int
    main_reload(void)
    {
    	struct rad_conf *xconf;
    
    	if ((xconf = parse_config(conffile)) == NULL)
    		return (-1);
    
    	if (main_imsg_send_config(xconf) == -1)
    		return (-1);
    
    	merge_config(main_conf, xconf);
    
    	return (0);
    }
    
    int
    main_imsg_send_config(struct rad_conf *xconf)
    {
    	struct ra_iface_conf	*ra_iface_conf;
    	struct ra_prefix_conf	*ra_prefix_conf;
    	struct ra_rdnss_conf	*ra_rdnss_conf;
    	struct ra_dnssl_conf	*ra_dnssl_conf;
    
    	/* Send fixed part of config to children. */
    	if (main_sendboth(IMSG_RECONF_CONF, xconf, sizeof(*xconf)) == -1)
    		return (-1);
    
    	/* send global dns options to children */
    	SIMPLEQ_FOREACH(ra_rdnss_conf, &xconf->ra_options.ra_rdnss_list,
    	    entry) {
    		if (main_sendboth(IMSG_RECONF_RA_RDNSS, ra_rdnss_conf,
    		    sizeof(*ra_rdnss_conf)) == -1)
    			return (-1);
    	}
    	SIMPLEQ_FOREACH(ra_dnssl_conf, &xconf->ra_options.ra_dnssl_list,
    	    entry) {
    		if (main_sendboth(IMSG_RECONF_RA_DNSSL, ra_dnssl_conf,
    		    sizeof(*ra_dnssl_conf)) == -1)
    			return (-1);
    	}
    
    	/* Send the interface list to children. */
    	SIMPLEQ_FOREACH(ra_iface_conf, &xconf->ra_iface_list, entry) {
    		if (main_sendboth(IMSG_RECONF_RA_IFACE, ra_iface_conf,
    		    sizeof(*ra_iface_conf)) == -1)
    			return (-1);
    		if (ra_iface_conf->autoprefix) {
    			if (main_sendboth(IMSG_RECONF_RA_AUTOPREFIX,
    			    ra_iface_conf->autoprefix,
    			    sizeof(*ra_iface_conf->autoprefix)) == -1)
    				return (-1);
    		}
    		SIMPLEQ_FOREACH(ra_prefix_conf, &ra_iface_conf->ra_prefix_list,
    		    entry) {
    			if (main_sendboth(IMSG_RECONF_RA_PREFIX,
    			    ra_prefix_conf, sizeof(*ra_prefix_conf)) == -1)
    				return (-1);
    		}
    		SIMPLEQ_FOREACH(ra_rdnss_conf,
    		    &ra_iface_conf->ra_options.ra_rdnss_list, entry) {
    			if (main_sendboth(IMSG_RECONF_RA_RDNSS, ra_rdnss_conf,
    			    sizeof(*ra_rdnss_conf)) == -1)
    				return (-1);
    		}
    		SIMPLEQ_FOREACH(ra_dnssl_conf,
    		    &ra_iface_conf->ra_options.ra_dnssl_list, entry) {
    			if (main_sendboth(IMSG_RECONF_RA_DNSSL, ra_dnssl_conf,
    			    sizeof(*ra_dnssl_conf)) == -1)
    				return (-1);
    		}
    	}
    
    	/* Tell children the revised config is now complete. */
    	if (main_sendboth(IMSG_RECONF_END, NULL, 0) == -1)
    		return (-1);
    
    	return (0);
    }
    
    int
    main_sendboth(enum imsg_type type, void *buf, uint16_t len)
    {
    	if (imsg_compose_event(iev_frontend, type, 0, 0, -1, buf, len) == -1)
    		return (-1);
    	if (imsg_compose_event(iev_engine, type, 0, 0, -1, buf, len) == -1)
    		return (-1);
    	return (0);
    }
    
    void
    free_ra_iface_conf(struct ra_iface_conf *ra_iface_conf)
    {
    	struct ra_prefix_conf	*prefix;
    
    	if (!ra_iface_conf)
    		return;
    
    	free(ra_iface_conf->autoprefix);
    
    	while ((prefix = SIMPLEQ_FIRST(&ra_iface_conf->ra_prefix_list)) !=
    	    NULL) {
    		SIMPLEQ_REMOVE_HEAD(&ra_iface_conf->ra_prefix_list, entry);
    		free(prefix);
    	}
    
    	free_dns_options(&ra_iface_conf->ra_options);
    
    	free(ra_iface_conf);
    }
    
    void
    free_dns_options(struct ra_options_conf *ra_options)
    {
    	struct ra_rdnss_conf	*ra_rdnss;
    	struct ra_dnssl_conf	*ra_dnssl;
    
    	while ((ra_rdnss = SIMPLEQ_FIRST(&ra_options->ra_rdnss_list)) != NULL) {
    		SIMPLEQ_REMOVE_HEAD(&ra_options->ra_rdnss_list, entry);
    		free(ra_rdnss);
    	}
    	ra_options->rdnss_count = 0;
    
    	while ((ra_dnssl = SIMPLEQ_FIRST(&ra_options->ra_dnssl_list)) != NULL) {
    		SIMPLEQ_REMOVE_HEAD(&ra_options->ra_dnssl_list, entry);
    		free(ra_dnssl);
    	}
    	ra_options->dnssl_len = 0;
    }
    
    void
    merge_config(struct rad_conf *conf, struct rad_conf *xconf)
    {
    	struct ra_iface_conf	*ra_iface_conf;
    
    	/* Remove & discard existing interfaces. */
    	while ((ra_iface_conf = SIMPLEQ_FIRST(&conf->ra_iface_list)) != NULL) {
    		SIMPLEQ_REMOVE_HEAD(&conf->ra_iface_list, entry);
    		free_ra_iface_conf(ra_iface_conf);
    	}
    	free_dns_options(&conf->ra_options);
    
    	conf->ra_options = xconf->ra_options;
    	SIMPLEQ_INIT(&conf->ra_options.ra_rdnss_list);
    	SIMPLEQ_INIT(&conf->ra_options.ra_dnssl_list);
    
    	/* Add new interfaces. */
    	SIMPLEQ_CONCAT(&conf->ra_iface_list, &xconf->ra_iface_list);
    
    	/* Add dns options */
    	SIMPLEQ_CONCAT(&conf->ra_options.ra_rdnss_list,
    	    &xconf->ra_options.ra_rdnss_list);
    	SIMPLEQ_CONCAT(&conf->ra_options.ra_dnssl_list,
    	    &xconf->ra_options.ra_dnssl_list);
    	free(xconf);
    }
    
    struct rad_conf *
    config_new_empty(void)
    {
    	struct rad_conf	*xconf;
    
    	xconf = calloc(1, sizeof(*xconf));
    	if (xconf == NULL)
    		fatal(NULL);
    
    	SIMPLEQ_INIT(&xconf->ra_iface_list);
    
    	xconf->ra_options.dfr = 1;
    	xconf->ra_options.cur_hl = 0;
    	xconf->ra_options.m_flag = 0;
    	xconf->ra_options.o_flag = 0;
    	xconf->ra_options.router_lifetime = ADV_DEFAULT_LIFETIME;
    	xconf->ra_options.reachable_time = 0;
    	xconf->ra_options.retrans_timer = 0;
    	xconf->ra_options.mtu = 0;
    	xconf->ra_options.rdns_lifetime = DEFAULT_RDNS_LIFETIME;
    	SIMPLEQ_INIT(&xconf->ra_options.ra_rdnss_list);
    	SIMPLEQ_INIT(&xconf->ra_options.ra_dnssl_list);
    
    	return (xconf);
    }
    
    void
    config_clear(struct rad_conf *conf)
    {
    	struct rad_conf	*xconf;
    
    	/* Merge current config with an empty config. */
    	xconf = config_new_empty();
    	merge_config(conf, xconf);
    
    	free(conf);
    }
    
    void
    mask_prefix(struct in6_addr* in6, int len)
    {
    	uint8_t	bitmask[8] = {0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe};
    	int	i, skip;
    
    	if (len < 0 || len > 128)
    		fatalx("invalid prefix length: %d", len);
    
    	skip = len / 8;
    
    	if (skip < 16)
    		in6->s6_addr[skip] &= bitmask[len % 8];
    
    	for (i = skip + 1; i < 16; i++)
    		in6->s6_addr[i] = 0;
    }
    
    const char*
    sin6_to_str(struct sockaddr_in6 *sin6)
    {
    	static char hbuf[NI_MAXHOST];
    	int error;
    
    	error = getnameinfo((struct sockaddr *)sin6, sin6->sin6_len, hbuf,
    	    sizeof(hbuf), NULL, 0, NI_NUMERICHOST | NI_NUMERICSERV);
    	if (error) {
    		log_warnx("%s", gai_strerror(error));
    		strlcpy(hbuf, "unknown", sizeof(hbuf));
    	}
    	return hbuf;
    }
    
    const char*
    in6_to_str(struct in6_addr *in6)
    {
    
    	struct sockaddr_in6	sin6;
    
    	memset(&sin6, 0, sizeof(sin6));
    	sin6.sin6_len = sizeof(sin6);
    	sin6.sin6_family = AF_INET6;
    	sin6.sin6_addr = *in6;
    
    	return (sin6_to_str(&sin6));
    }
    
    void
    open_icmp6sock(int rdomain)
    {
    	int			 icmp6sock, on = 1, off = 0;
    
    	log_debug("%s: %d", __func__, rdomain);
    
    	if ((icmp6sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC,
    	    IPPROTO_ICMPV6)) == -1)
    		fatal("ICMPv6 socket");
    
    	if (setsockopt(icmp6sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
    	    sizeof(on)) == -1)
    		fatal("IPV6_RECVPKTINFO");
    
    	if (setsockopt(icmp6sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
    	    sizeof(on)) == -1)
    		fatal("IPV6_RECVHOPLIMIT");
    
    	if (setsockopt(icmp6sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &off,
    	    sizeof(off)) == -1)
    		fatal("IPV6_RECVHOPLIMIT");
    
    	if (setsockopt(icmp6sock, SOL_SOCKET, SO_RTABLE, &rdomain,
    	    sizeof(rdomain)) == -1) {
    		/* we might race against removal of the rdomain */
    		log_warn("setsockopt SO_RTABLE");
    		close(icmp6sock);
    		return;
    	}
    
    	main_imsg_compose_frontend(IMSG_ICMP6SOCK, icmp6sock, &rdomain,
    	    sizeof(rdomain));
    }