main.c revision 290001
1#include <config.h>
2
3#include <event2/util.h>
4#include <event2/event.h>
5
6#include "ntp_workimpl.h"
7#ifdef WORK_THREAD
8# include <event2/thread.h>
9#endif
10
11#include "main.h"
12#include "ntp_libopts.h"
13#include "kod_management.h"
14#include "networking.h"
15#include "utilities.h"
16#include "log.h"
17#include "libntp.h"
18
19
20int shutting_down;
21int time_derived;
22int time_adjusted;
23int n_pending_dns = 0;
24int n_pending_ntp = 0;
25int ai_fam_pref = AF_UNSPEC;
26int ntpver = 4;
27double steplimit = -1;
28SOCKET sock4 = -1;		/* Socket for IPv4 */
29SOCKET sock6 = -1;		/* Socket for IPv6 */
30/*
31** BCAST *must* listen on port 123 (by default), so we can only
32** use the UCST sockets (above) if they too are using port 123
33*/
34SOCKET bsock4 = -1;		/* Broadcast Socket for IPv4 */
35SOCKET bsock6 = -1;		/* Broadcast Socket for IPv6 */
36struct event_base *base;
37struct event *ev_sock4;
38struct event *ev_sock6;
39struct event *ev_worker_timeout;
40struct event *ev_xmt_timer;
41
42struct dns_ctx {
43	const char *	name;
44	int		flags;
45#define CTX_BCST	0x0001
46#define CTX_UCST	0x0002
47#define CTX_xCST	0x0003
48#define CTX_CONC	0x0004
49#define CTX_unused	0xfffd
50	int		key_id;
51	struct timeval	timeout;
52	struct key *	key;
53};
54
55typedef struct sent_pkt_tag sent_pkt;
56struct sent_pkt_tag {
57	sent_pkt *		link;
58	struct dns_ctx *	dctx;
59	sockaddr_u		addr;
60	time_t			stime;
61	int			done;
62	struct pkt		x_pkt;
63};
64
65typedef struct xmt_ctx_tag xmt_ctx;
66struct xmt_ctx_tag {
67	xmt_ctx *		link;
68	SOCKET			sock;
69	time_t			sched;
70	sent_pkt *		spkt;
71};
72
73struct timeval	gap;
74xmt_ctx *	xmt_q;
75struct key *	keys = NULL;
76int		response_timeout;
77struct timeval	response_tv;
78struct timeval	start_tv;
79/* check the timeout at least once per second */
80struct timeval	wakeup_tv = { 0, 888888 };
81
82sent_pkt *	fam_listheads[2];
83#define v4_pkts_list	(fam_listheads[0])
84#define v6_pkts_list	(fam_listheads[1])
85
86static union {
87	struct pkt pkt;
88	char   buf[LEN_PKT_NOMAC + NTP_MAXEXTEN + MAX_MAC_LEN];
89} rbuf;
90
91#define r_pkt  rbuf.pkt
92
93#ifdef HAVE_DROPROOT
94int droproot;			/* intres imports these */
95int root_dropped;
96#endif
97u_long current_time;		/* libntp/authkeys.c */
98
99void open_sockets(void);
100void handle_lookup(const char *name, int flags);
101void sntp_addremove_fd(int fd, int is_pipe, int remove_it);
102void worker_timeout(evutil_socket_t, short, void *);
103void worker_resp_cb(evutil_socket_t, short, void *);
104void sntp_name_resolved(int, int, void *, const char *, const char *,
105			const struct addrinfo *,
106			const struct addrinfo *);
107void queue_xmt(SOCKET sock, struct dns_ctx *dctx, sent_pkt *spkt,
108	       u_int xmt_delay);
109void xmt_timer_cb(evutil_socket_t, short, void *ptr);
110void xmt(xmt_ctx *xctx);
111int  check_kod(const struct addrinfo *ai);
112void timeout_query(sent_pkt *);
113void timeout_queries(void);
114void sock_cb(evutil_socket_t, short, void *);
115void check_exit_conditions(void);
116void sntp_libevent_log_cb(int, const char *);
117void set_li_vn_mode(struct pkt *spkt, char leap, char version, char mode);
118int  set_time(double offset);
119void dec_pending_ntp(const char *, sockaddr_u *);
120int  libevent_version_ok(void);
121int  gettimeofday_cached(struct event_base *b, struct timeval *tv);
122
123
124/*
125 * The actual main function.
126 */
127int
128sntp_main (
129	int argc,
130	char **argv,
131	const char *sntpVersion
132	)
133{
134	int			i;
135	int			exitcode;
136	int			optct;
137	struct event_config *	evcfg;
138
139	/* Initialize logging system - sets up progname */
140	sntp_init_logging(argv[0]);
141
142	if (!libevent_version_ok())
143		exit(EX_SOFTWARE);
144
145	init_lib();
146	init_auth();
147
148	optct = ntpOptionProcess(&sntpOptions, argc, argv);
149	argc -= optct;
150	argv += optct;
151
152
153	debug = OPT_VALUE_SET_DEBUG_LEVEL;
154
155	TRACE(2, ("init_lib() done, %s%s\n",
156		  (ipv4_works)
157		      ? "ipv4_works "
158		      : "",
159		  (ipv6_works)
160		      ? "ipv6_works "
161		      : ""));
162	ntpver = OPT_VALUE_NTPVERSION;
163	steplimit = OPT_VALUE_STEPLIMIT / 1e3;
164	gap.tv_usec = max(0, OPT_VALUE_GAP * 1000);
165	gap.tv_usec = min(gap.tv_usec, 999999);
166
167	if (HAVE_OPT(LOGFILE))
168		open_logfile(OPT_ARG(LOGFILE));
169
170	msyslog(LOG_INFO, "%s", sntpVersion);
171
172	if (0 == argc && !HAVE_OPT(BROADCAST) && !HAVE_OPT(CONCURRENT)) {
173		printf("%s: Must supply at least one of -b hostname, -c hostname, or hostname.\n",
174		       progname);
175		exit(EX_USAGE);
176	}
177
178
179	/*
180	** Eventually, we probably want:
181	** - separate bcst and ucst timeouts (why?)
182	** - multiple --timeout values in the commandline
183	*/
184
185	response_timeout = OPT_VALUE_TIMEOUT;
186	response_tv.tv_sec = response_timeout;
187	response_tv.tv_usec = 0;
188
189	/* IPv6 available? */
190	if (isc_net_probeipv6() != ISC_R_SUCCESS) {
191		ai_fam_pref = AF_INET;
192		TRACE(1, ("No ipv6 support available, forcing ipv4\n"));
193	} else {
194		/* Check for options -4 and -6 */
195		if (HAVE_OPT(IPV4))
196			ai_fam_pref = AF_INET;
197		else if (HAVE_OPT(IPV6))
198			ai_fam_pref = AF_INET6;
199	}
200
201	/* TODO: Parse config file if declared */
202
203	/*
204	** Init the KOD system.
205	** For embedded systems with no writable filesystem,
206	** -K /dev/null can be used to disable KoD storage.
207	*/
208	kod_init_kod_db(OPT_ARG(KOD), FALSE);
209
210	// HMS: Should we use arg-defalt for this too?
211	if (HAVE_OPT(KEYFILE))
212		auth_init(OPT_ARG(KEYFILE), &keys);
213
214	/*
215	** Considering employing a variable that prevents functions of doing
216	** anything until everything is initialized properly
217	**
218	** HMS: What exactly does the above mean?
219	*/
220	event_set_log_callback(&sntp_libevent_log_cb);
221	if (debug > 0)
222		event_enable_debug_mode();
223#ifdef WORK_THREAD
224	evthread_use_pthreads();
225	/* we use libevent from main thread only, locks should be academic */
226	if (debug > 0)
227		evthread_enable_lock_debuging();
228#endif
229	evcfg = event_config_new();
230	if (NULL == evcfg) {
231		printf("%s: event_config_new() failed!\n", progname);
232		return -1;
233	}
234#ifndef HAVE_SOCKETPAIR
235	event_config_require_features(evcfg, EV_FEATURE_FDS);
236#endif
237	/* all libevent calls are from main thread */
238	/* event_config_set_flag(evcfg, EVENT_BASE_FLAG_NOLOCK); */
239	base = event_base_new_with_config(evcfg);
240	event_config_free(evcfg);
241	if (NULL == base) {
242		printf("%s: event_base_new() failed!\n", progname);
243		return -1;
244	}
245
246	/* wire into intres resolver */
247	worker_per_query = TRUE;
248	addremove_io_fd = &sntp_addremove_fd;
249
250	open_sockets();
251
252	if (HAVE_OPT(BROADCAST)) {
253		int		cn = STACKCT_OPT(  BROADCAST );
254		const char **	cp = STACKLST_OPT( BROADCAST );
255
256		while (cn-- > 0) {
257			handle_lookup(*cp, CTX_BCST);
258			cp++;
259		}
260	}
261
262	if (HAVE_OPT(CONCURRENT)) {
263		int		cn = STACKCT_OPT( CONCURRENT );
264		const char **	cp = STACKLST_OPT( CONCURRENT );
265
266		while (cn-- > 0) {
267			handle_lookup(*cp, CTX_UCST | CTX_CONC);
268			cp++;
269		}
270	}
271
272	for (i = 0; i < argc; ++i)
273		handle_lookup(argv[i], CTX_UCST);
274
275	gettimeofday_cached(base, &start_tv);
276	event_base_dispatch(base);
277	event_base_free(base);
278
279	if (!time_adjusted &&
280	    (ENABLED_OPT(STEP) || ENABLED_OPT(SLEW)))
281		exitcode = 1;
282	else
283		exitcode = 0;
284
285	return exitcode;
286}
287
288
289/*
290** open sockets and make them non-blocking
291*/
292void
293open_sockets(
294	void
295	)
296{
297	sockaddr_u	name;
298
299	if (-1 == sock4) {
300		sock4 = socket(PF_INET, SOCK_DGRAM, 0);
301		if (-1 == sock4) {
302			/* error getting a socket */
303			msyslog(LOG_ERR, "open_sockets: socket(PF_INET) failed: %m");
304			exit(1);
305		}
306		/* Make it non-blocking */
307		make_socket_nonblocking(sock4);
308
309		/* Let's try using a wildcard... */
310		ZERO(name);
311		AF(&name) = AF_INET;
312		SET_ADDR4N(&name, INADDR_ANY);
313		SET_PORT(&name, (HAVE_OPT(USERESERVEDPORT) ? 123 : 0));
314
315		if (-1 == bind(sock4, &name.sa,
316			       SOCKLEN(&name))) {
317			msyslog(LOG_ERR, "open_sockets: bind(sock4) failed: %m");
318			exit(1);
319		}
320
321		/* Register an NTP callback for recv/timeout */
322		ev_sock4 = event_new(base, sock4,
323				     EV_TIMEOUT | EV_READ | EV_PERSIST,
324				     &sock_cb, NULL);
325		if (NULL == ev_sock4) {
326			msyslog(LOG_ERR,
327				"open_sockets: event_new(base, sock4) failed!");
328		} else {
329			event_add(ev_sock4, &wakeup_tv);
330		}
331	}
332
333	/* We may not always have IPv6... */
334	if (-1 == sock6 && ipv6_works) {
335		sock6 = socket(PF_INET6, SOCK_DGRAM, 0);
336		if (-1 == sock6 && ipv6_works) {
337			/* error getting a socket */
338			msyslog(LOG_ERR, "open_sockets: socket(PF_INET6) failed: %m");
339			exit(1);
340		}
341		/* Make it non-blocking */
342		make_socket_nonblocking(sock6);
343
344		/* Let's try using a wildcard... */
345		ZERO(name);
346		AF(&name) = AF_INET6;
347		SET_ADDR6N(&name, in6addr_any);
348		SET_PORT(&name, (HAVE_OPT(USERESERVEDPORT) ? 123 : 0));
349
350		if (-1 == bind(sock6, &name.sa,
351			       SOCKLEN(&name))) {
352			msyslog(LOG_ERR, "open_sockets: bind(sock6) failed: %m");
353			exit(1);
354		}
355		/* Register an NTP callback for recv/timeout */
356		ev_sock6 = event_new(base, sock6,
357				     EV_TIMEOUT | EV_READ | EV_PERSIST,
358				     &sock_cb, NULL);
359		if (NULL == ev_sock6) {
360			msyslog(LOG_ERR,
361				"open_sockets: event_new(base, sock6) failed!");
362		} else {
363			event_add(ev_sock6, &wakeup_tv);
364		}
365	}
366
367	return;
368}
369
370
371/*
372** handle_lookup
373*/
374void
375handle_lookup(
376	const char *name,
377	int flags
378	)
379{
380	struct addrinfo	hints;	/* Local copy is OK */
381	struct dns_ctx *ctx;
382	long		l;
383	char *		name_copy;
384	size_t		name_sz;
385	size_t		octets;
386
387	TRACE(1, ("handle_lookup(%s,%#x)\n", name, flags));
388
389	ZERO(hints);
390	hints.ai_family = ai_fam_pref;
391	hints.ai_flags = AI_CANONNAME | Z_AI_NUMERICSERV;
392	/*
393	** Unless we specify a socktype, we'll get at least two
394	** entries for each address: one for TCP and one for
395	** UDP. That's not what we want.
396	*/
397	hints.ai_socktype = SOCK_DGRAM;
398	hints.ai_protocol = IPPROTO_UDP;
399
400	name_sz = 1 + strlen(name);
401	octets = sizeof(*ctx) + name_sz;	// Space for a ctx and the name
402	ctx = emalloc_zero(octets);		// ctx at ctx[0]
403	name_copy = (char *)(ctx + 1);		// Put the name at ctx[1]
404	memcpy(name_copy, name, name_sz);	// copy the name to ctx[1]
405	ctx->name = name_copy;			// point to it...
406	ctx->flags = flags;
407	ctx->timeout = response_tv;
408
409	/* The following should arguably be passed in... */
410	if (ENABLED_OPT(AUTHENTICATION) &&
411	    atoint(OPT_ARG(AUTHENTICATION), &l)) {
412		ctx->key_id = l;
413		get_key(ctx->key_id, &ctx->key);
414	} else {
415		ctx->key_id = -1;
416		ctx->key = NULL;
417	}
418
419	++n_pending_dns;
420	getaddrinfo_sometime(name, "123", &hints, 0,
421			     &sntp_name_resolved, ctx);
422}
423
424
425/*
426** DNS Callback:
427** - For each IP:
428** - - open a socket
429** - - increment n_pending_ntp
430** - - send a request if this is a Unicast callback
431** - - queue wait for response
432** - decrement n_pending_dns
433*/
434void
435sntp_name_resolved(
436	int			rescode,
437	int			gai_errno,
438	void *			context,
439	const char *		name,
440	const char *		service,
441	const struct addrinfo *	hints,
442	const struct addrinfo *	addr
443	)
444{
445	struct dns_ctx *	dctx;
446	sent_pkt *		spkt;
447	const struct addrinfo *	ai;
448	SOCKET			sock;
449	u_int			xmt_delay_v4;
450	u_int			xmt_delay_v6;
451	u_int			xmt_delay;
452	size_t			octets;
453
454	xmt_delay_v4 = 0;
455	xmt_delay_v6 = 0;
456	dctx = context;
457	if (rescode) {
458#ifdef EAI_SYSTEM
459		if (EAI_SYSTEM == rescode) {
460			errno = gai_errno;
461			mfprintf(stderr, "%s lookup error %m\n",
462				 dctx->name);
463		} else
464#endif
465			fprintf(stderr, "%s lookup error %s\n",
466				dctx->name, gai_strerror(rescode));
467	} else {
468		TRACE(3, ("%s [%s]\n", dctx->name,
469			  (addr->ai_canonname != NULL)
470			      ? addr->ai_canonname
471			      : ""));
472
473		for (ai = addr; ai != NULL; ai = ai->ai_next) {
474
475			if (check_kod(ai))
476				continue;
477
478			switch (ai->ai_family) {
479
480			case AF_INET:
481				sock = sock4;
482				xmt_delay = xmt_delay_v4;
483				xmt_delay_v4++;
484				break;
485
486			case AF_INET6:
487				if (!ipv6_works)
488					continue;
489
490				sock = sock6;
491				xmt_delay = xmt_delay_v6;
492				xmt_delay_v6++;
493				break;
494
495			default:
496				msyslog(LOG_ERR, "sntp_name_resolved: unexpected ai_family: %d",
497					ai->ai_family);
498				exit(1);
499				break;
500			}
501
502			/*
503			** We're waiting for a response for either unicast
504			** or broadcast, so...
505			*/
506			++n_pending_ntp;
507
508			/* If this is for a unicast IP, queue a request */
509			if (dctx->flags & CTX_UCST) {
510				spkt = emalloc_zero(sizeof(*spkt));
511				spkt->dctx = dctx;
512				octets = min(ai->ai_addrlen, sizeof(spkt->addr));
513				memcpy(&spkt->addr, ai->ai_addr, octets);
514				queue_xmt(sock, dctx, spkt, xmt_delay);
515			}
516		}
517	}
518	/* n_pending_dns really should be >0 here... */
519	--n_pending_dns;
520	check_exit_conditions();
521}
522
523
524/*
525** queue_xmt
526*/
527void
528queue_xmt(
529	SOCKET			sock,
530	struct dns_ctx *	dctx,
531	sent_pkt *		spkt,
532	u_int			xmt_delay
533	)
534{
535	sockaddr_u *	dest;
536	sent_pkt **	pkt_listp;
537	sent_pkt *	match;
538	xmt_ctx *	xctx;
539	struct timeval	start_cb;
540	struct timeval	delay;
541
542	dest = &spkt->addr;
543	if (IS_IPV6(dest))
544		pkt_listp = &v6_pkts_list;
545	else
546		pkt_listp = &v4_pkts_list;
547
548	/* reject attempts to add address already listed */
549	for (match = *pkt_listp; match != NULL; match = match->link) {
550		if (ADDR_PORT_EQ(&spkt->addr, &match->addr)) {
551			if (strcasecmp(spkt->dctx->name,
552				       match->dctx->name))
553				printf("%s %s duplicate address from %s ignored.\n",
554				       sptoa(&match->addr),
555				       match->dctx->name,
556				       spkt->dctx->name);
557			else
558				printf("%s %s, duplicate address ignored.\n",
559				       sptoa(&match->addr),
560				       match->dctx->name);
561			dec_pending_ntp(spkt->dctx->name, &spkt->addr);
562			free(spkt);
563			return;
564		}
565	}
566
567	LINK_SLIST(*pkt_listp, spkt, link);
568
569	xctx = emalloc_zero(sizeof(*xctx));
570	xctx->sock = sock;
571	xctx->spkt = spkt;
572	gettimeofday_cached(base, &start_cb);
573	xctx->sched = start_cb.tv_sec + (2 * xmt_delay);
574
575	LINK_SORT_SLIST(xmt_q, xctx, (xctx->sched < L_S_S_CUR()->sched),
576			link, xmt_ctx);
577	if (xmt_q == xctx) {
578		/*
579		 * The new entry is the first scheduled.  The timer is
580		 * either not active or is set for the second xmt
581		 * context in xmt_q.
582		 */
583		if (NULL == ev_xmt_timer)
584			ev_xmt_timer = event_new(base, INVALID_SOCKET,
585						 EV_TIMEOUT,
586						 &xmt_timer_cb, NULL);
587		if (NULL == ev_xmt_timer) {
588			msyslog(LOG_ERR,
589				"queue_xmt: event_new(base, -1, EV_TIMEOUT) failed!");
590			exit(1);
591		}
592		ZERO(delay);
593		if (xctx->sched > start_cb.tv_sec)
594			delay.tv_sec = xctx->sched - start_cb.tv_sec;
595		event_add(ev_xmt_timer, &delay);
596		TRACE(2, ("queue_xmt: xmt timer for %u usec\n",
597			  (u_int)delay.tv_usec));
598	}
599}
600
601
602/*
603** xmt_timer_cb
604*/
605void
606xmt_timer_cb(
607	evutil_socket_t	fd,
608	short		what,
609	void *		ctx
610	)
611{
612	struct timeval	start_cb;
613	struct timeval	delay;
614	xmt_ctx *	x;
615
616	UNUSED_ARG(fd);
617	UNUSED_ARG(ctx);
618	DEBUG_INSIST(EV_TIMEOUT == what);
619
620	if (NULL == xmt_q || shutting_down)
621		return;
622	gettimeofday_cached(base, &start_cb);
623	if (xmt_q->sched <= start_cb.tv_sec) {
624		UNLINK_HEAD_SLIST(x, xmt_q, link);
625		TRACE(2, ("xmt_timer_cb: at .%6.6u -> %s\n",
626			  (u_int)start_cb.tv_usec, stoa(&x->spkt->addr)));
627		xmt(x);
628		free(x);
629		if (NULL == xmt_q)
630			return;
631	}
632	if (xmt_q->sched <= start_cb.tv_sec) {
633		event_add(ev_xmt_timer, &gap);
634		TRACE(2, ("xmt_timer_cb: at .%6.6u gap %6.6u\n",
635			  (u_int)start_cb.tv_usec,
636			  (u_int)gap.tv_usec));
637	} else {
638		delay.tv_sec = xmt_q->sched - start_cb.tv_sec;
639		delay.tv_usec = 0;
640		event_add(ev_xmt_timer, &delay);
641		TRACE(2, ("xmt_timer_cb: at .%6.6u next %ld seconds\n",
642			  (u_int)start_cb.tv_usec,
643			  (long)delay.tv_sec));
644	}
645}
646
647
648/*
649** xmt()
650*/
651void
652xmt(
653	xmt_ctx *	xctx
654	)
655{
656	SOCKET		sock = xctx->sock;
657	struct dns_ctx *dctx = xctx->spkt->dctx;
658	sent_pkt *	spkt = xctx->spkt;
659	sockaddr_u *	dst = &spkt->addr;
660	struct timeval	tv_xmt;
661	struct pkt	x_pkt;
662	size_t		pkt_len;
663	int		sent;
664
665	if (0 != gettimeofday(&tv_xmt, NULL)) {
666		msyslog(LOG_ERR,
667			"xmt: gettimeofday() failed: %m");
668		exit(1);
669	}
670	tv_xmt.tv_sec += JAN_1970;
671
672	pkt_len = generate_pkt(&x_pkt, &tv_xmt, dctx->key_id,
673			       dctx->key);
674
675	sent = sendpkt(sock, dst, &x_pkt, pkt_len);
676	if (sent) {
677		/* Save the packet we sent... */
678		memcpy(&spkt->x_pkt, &x_pkt, min(sizeof(spkt->x_pkt),
679		       pkt_len));
680		spkt->stime = tv_xmt.tv_sec - JAN_1970;
681
682		TRACE(2, ("xmt: %lx.%6.6u %s %s\n", (u_long)tv_xmt.tv_sec,
683			  (u_int)tv_xmt.tv_usec, dctx->name, stoa(dst)));
684	} else {
685		dec_pending_ntp(dctx->name, dst);
686	}
687
688	return;
689}
690
691
692/*
693 * timeout_queries() -- give up on unrequited NTP queries
694 */
695void
696timeout_queries(void)
697{
698	struct timeval	start_cb;
699	u_int		idx;
700	sent_pkt *	head;
701	sent_pkt *	spkt;
702	sent_pkt *	spkt_next;
703	long		age;
704	int didsomething = 0;
705
706	TRACE(3, ("timeout_queries: called to check %u items\n",
707		  (unsigned)COUNTOF(fam_listheads)));
708
709	gettimeofday_cached(base, &start_cb);
710	for (idx = 0; idx < COUNTOF(fam_listheads); idx++) {
711		head = fam_listheads[idx];
712		for (spkt = head; spkt != NULL; spkt = spkt_next) {
713			char xcst;
714
715			didsomething = 1;
716			switch (spkt->dctx->flags & CTX_xCST) {
717			    case CTX_BCST:
718				xcst = 'B';
719				break;
720
721			    case CTX_UCST:
722				xcst = 'U';
723				break;
724
725			    default:
726				INSIST(!"spkt->dctx->flags neither UCST nor BCST");
727				break;
728			}
729
730			spkt_next = spkt->link;
731			if (0 == spkt->stime || spkt->done)
732				continue;
733			age = start_cb.tv_sec - spkt->stime;
734			TRACE(3, ("%s %s %cCST age %ld\n",
735				  stoa(&spkt->addr),
736				  spkt->dctx->name, xcst, age));
737			if (age > response_timeout)
738				timeout_query(spkt);
739		}
740	}
741	// Do we care about didsomething?
742	TRACE(3, ("timeout_queries: didsomething is %d, age is %ld\n",
743		  didsomething, (long) (start_cb.tv_sec - start_tv.tv_sec)));
744	if (start_cb.tv_sec - start_tv.tv_sec > response_timeout) {
745		TRACE(3, ("timeout_queries: bail!\n"));
746		event_base_loopexit(base, NULL);
747		shutting_down = TRUE;
748	}
749}
750
751
752void dec_pending_ntp(
753	const char *	name,
754	sockaddr_u *	server
755	)
756{
757	if (n_pending_ntp > 0) {
758		--n_pending_ntp;
759		check_exit_conditions();
760	} else {
761		INSIST(0 == n_pending_ntp);
762		TRACE(1, ("n_pending_ntp was zero before decrement for %s\n",
763			  hostnameaddr(name, server)));
764	}
765}
766
767
768void timeout_query(
769	sent_pkt *	spkt
770	)
771{
772	sockaddr_u *	server;
773	char		xcst;
774
775
776	switch (spkt->dctx->flags & CTX_xCST) {
777	    case CTX_BCST:
778		xcst = 'B';
779		break;
780
781	    case CTX_UCST:
782		xcst = 'U';
783		break;
784
785	    default:
786		INSIST(!"spkt->dctx->flags neither UCST nor BCST");
787		break;
788	}
789	spkt->done = TRUE;
790	server = &spkt->addr;
791	msyslog(LOG_INFO, "%s no %cCST response after %d seconds",
792		hostnameaddr(spkt->dctx->name, server), xcst,
793		response_timeout);
794	dec_pending_ntp(spkt->dctx->name, server);
795	return;
796}
797
798
799/*
800** check_kod
801*/
802int
803check_kod(
804	const struct addrinfo *	ai
805	)
806{
807	char *hostname;
808	struct kod_entry *reason;
809
810	/* Is there a KoD on file for this address? */
811	hostname = addrinfo_to_str(ai);
812	TRACE(2, ("check_kod: checking <%s>\n", hostname));
813	if (search_entry(hostname, &reason)) {
814		printf("prior KoD for %s, skipping.\n",
815			hostname);
816		free(reason);
817		free(hostname);
818
819		return 1;
820	}
821	free(hostname);
822
823	return 0;
824}
825
826
827/*
828** Socket readable/timeout Callback:
829** Read in the packet
830** Unicast:
831** - close socket
832** - decrement n_pending_ntp
833** - If packet is good, set the time and "exit"
834** Broadcast:
835** - If packet is good, set the time and "exit"
836*/
837void
838sock_cb(
839	evutil_socket_t fd,
840	short what,
841	void *ptr
842	)
843{
844	sockaddr_u	sender;
845	sockaddr_u *	psau;
846	sent_pkt **	p_pktlist;
847	sent_pkt *	spkt;
848	int		rpktl;
849	int		rc;
850
851	INSIST(sock4 == fd || sock6 == fd);
852
853	TRACE(3, ("sock_cb: event on sock%s:%s%s%s%s\n",
854		  (fd == sock6)
855		      ? "6"
856		      : "4",
857		  (what & EV_TIMEOUT) ? " timeout" : "",
858		  (what & EV_READ)    ? " read" : "",
859		  (what & EV_WRITE)   ? " write" : "",
860		  (what & EV_SIGNAL)  ? " signal" : ""));
861
862	if (!(EV_READ & what)) {
863		if (EV_TIMEOUT & what)
864			timeout_queries();
865
866		return;
867	}
868
869	/* Read in the packet */
870	rpktl = recvdata(fd, &sender, &rbuf, sizeof(rbuf));
871	if (rpktl < 0) {
872		msyslog(LOG_DEBUG, "recvfrom error %m");
873		return;
874	}
875
876	if (sock6 == fd)
877		p_pktlist = &v6_pkts_list;
878	else
879		p_pktlist = &v4_pkts_list;
880
881	for (spkt = *p_pktlist; spkt != NULL; spkt = spkt->link) {
882		psau = &spkt->addr;
883		if (SOCK_EQ(&sender, psau))
884			break;
885	}
886	if (NULL == spkt) {
887		msyslog(LOG_WARNING,
888			"Packet from unexpected source %s dropped",
889			sptoa(&sender));
890		return;
891	}
892
893	TRACE(1, ("sock_cb: %s %s\n", spkt->dctx->name,
894		  sptoa(&sender)));
895
896	rpktl = process_pkt(&r_pkt, &sender, rpktl, MODE_SERVER,
897			    &spkt->x_pkt, "sock_cb");
898
899	TRACE(2, ("sock_cb: process_pkt returned %d\n", rpktl));
900
901	/* If this is a Unicast packet, one down ... */
902	if (!spkt->done && (CTX_UCST & spkt->dctx->flags)) {
903		dec_pending_ntp(spkt->dctx->name, &spkt->addr);
904		spkt->done = TRUE;
905	}
906
907
908	/* If the packet is good, set the time and we're all done */
909	rc = handle_pkt(rpktl, &r_pkt, &spkt->addr, spkt->dctx->name);
910	if (0 != rc)
911		TRACE(1, ("sock_cb: handle_pkt() returned %d\n", rc));
912	check_exit_conditions();
913}
914
915
916/*
917 * check_exit_conditions()
918 *
919 * If sntp has a reply, ask the event loop to stop after this round of
920 * callbacks, unless --wait was used.
921 */
922void
923check_exit_conditions(void)
924{
925	if ((0 == n_pending_ntp && 0 == n_pending_dns) ||
926	    (time_derived && !HAVE_OPT(WAIT))) {
927		event_base_loopexit(base, NULL);
928		shutting_down = TRUE;
929	} else {
930		TRACE(2, ("%d NTP and %d name queries pending\n",
931			  n_pending_ntp, n_pending_dns));
932	}
933}
934
935
936/*
937 * sntp_addremove_fd() is invoked by the intres blocking worker code
938 * to read from a pipe, or to stop same.
939 */
940void sntp_addremove_fd(
941	int	fd,
942	int	is_pipe,
943	int	remove_it
944	)
945{
946	u_int		idx;
947	blocking_child *c;
948	struct event *	ev;
949
950#ifdef HAVE_SOCKETPAIR
951	if (is_pipe) {
952		/* sntp only asks for EV_FEATURE_FDS without HAVE_SOCKETPAIR */
953		msyslog(LOG_ERR, "fatal: pipes not supported on systems with socketpair()");
954		exit(1);
955	}
956#endif
957
958	c = NULL;
959	for (idx = 0; idx < blocking_children_alloc; idx++) {
960		c = blocking_children[idx];
961		if (NULL == c)
962			continue;
963		if (fd == c->resp_read_pipe)
964			break;
965	}
966	if (idx == blocking_children_alloc)
967		return;
968
969	if (remove_it) {
970		ev = c->resp_read_ctx;
971		c->resp_read_ctx = NULL;
972		event_del(ev);
973		event_free(ev);
974
975		return;
976	}
977
978	ev = event_new(base, fd, EV_READ | EV_PERSIST,
979		       &worker_resp_cb, c);
980	if (NULL == ev) {
981		msyslog(LOG_ERR,
982			"sntp_addremove_fd: event_new(base, fd) failed!");
983		return;
984	}
985	c->resp_read_ctx = ev;
986	event_add(ev, NULL);
987}
988
989
990/* called by forked intres child to close open descriptors */
991#ifdef WORK_FORK
992void
993kill_asyncio(
994	int	startfd
995	)
996{
997	if (INVALID_SOCKET != sock4) {
998		closesocket(sock4);
999		sock4 = INVALID_SOCKET;
1000	}
1001	if (INVALID_SOCKET != sock6) {
1002		closesocket(sock6);
1003		sock6 = INVALID_SOCKET;
1004	}
1005	if (INVALID_SOCKET != bsock4) {
1006		closesocket(sock4);
1007		sock4 = INVALID_SOCKET;
1008	}
1009	if (INVALID_SOCKET != bsock6) {
1010		closesocket(sock6);
1011		sock6 = INVALID_SOCKET;
1012	}
1013}
1014#endif
1015
1016
1017/*
1018 * worker_resp_cb() is invoked when resp_read_pipe is readable.
1019 */
1020void
1021worker_resp_cb(
1022	evutil_socket_t	fd,
1023	short		what,
1024	void *		ctx	/* blocking_child * */
1025	)
1026{
1027	blocking_child *	c;
1028
1029	DEBUG_INSIST(EV_READ & what);
1030	c = ctx;
1031	DEBUG_INSIST(fd == c->resp_read_pipe);
1032	process_blocking_resp(c);
1033}
1034
1035
1036/*
1037 * intres_timeout_req(s) is invoked in the parent to schedule an idle
1038 * timeout to fire in s seconds, if not reset earlier by a call to
1039 * intres_timeout_req(0), which clears any pending timeout.  When the
1040 * timeout expires, worker_idle_timer_fired() is invoked (again, in the
1041 * parent).
1042 *
1043 * sntp and ntpd each provide implementations adapted to their timers.
1044 */
1045void
1046intres_timeout_req(
1047	u_int	seconds		/* 0 cancels */
1048	)
1049{
1050	struct timeval	tv_to;
1051
1052	if (NULL == ev_worker_timeout) {
1053		ev_worker_timeout = event_new(base, -1,
1054					      EV_TIMEOUT | EV_PERSIST,
1055					      &worker_timeout, NULL);
1056		DEBUG_INSIST(NULL != ev_worker_timeout);
1057	} else {
1058		event_del(ev_worker_timeout);
1059	}
1060	if (0 == seconds)
1061		return;
1062	tv_to.tv_sec = seconds;
1063	tv_to.tv_usec = 0;
1064	event_add(ev_worker_timeout, &tv_to);
1065}
1066
1067
1068void
1069worker_timeout(
1070	evutil_socket_t	fd,
1071	short		what,
1072	void *		ctx
1073	)
1074{
1075	UNUSED_ARG(fd);
1076	UNUSED_ARG(ctx);
1077
1078	DEBUG_REQUIRE(EV_TIMEOUT & what);
1079	worker_idle_timer_fired();
1080}
1081
1082
1083void
1084sntp_libevent_log_cb(
1085	int		severity,
1086	const char *	msg
1087	)
1088{
1089	int		level;
1090
1091	switch (severity) {
1092
1093	default:
1094	case _EVENT_LOG_DEBUG:
1095		level = LOG_DEBUG;
1096		break;
1097
1098	case _EVENT_LOG_MSG:
1099		level = LOG_NOTICE;
1100		break;
1101
1102	case _EVENT_LOG_WARN:
1103		level = LOG_WARNING;
1104		break;
1105
1106	case _EVENT_LOG_ERR:
1107		level = LOG_ERR;
1108		break;
1109	}
1110
1111	msyslog(level, "%s", msg);
1112}
1113
1114
1115int
1116generate_pkt (
1117	struct pkt *x_pkt,
1118	const struct timeval *tv_xmt,
1119	int key_id,
1120	struct key *pkt_key
1121	)
1122{
1123	l_fp	xmt_fp;
1124	int	pkt_len;
1125	int	mac_size;
1126
1127	pkt_len = LEN_PKT_NOMAC;
1128	ZERO(*x_pkt);
1129	TVTOTS(tv_xmt, &xmt_fp);
1130	HTONL_FP(&xmt_fp, &x_pkt->xmt);
1131	x_pkt->stratum = STRATUM_TO_PKT(STRATUM_UNSPEC);
1132	x_pkt->ppoll = 8;
1133	/* FIXME! Modus broadcast + adr. check -> bdr. pkt */
1134	set_li_vn_mode(x_pkt, LEAP_NOTINSYNC, ntpver, 3);
1135	if (pkt_key != NULL) {
1136		x_pkt->exten[0] = htonl(key_id);
1137		mac_size = 20; /* max room for MAC */
1138		mac_size = make_mac((char *)x_pkt, pkt_len, mac_size,
1139				    pkt_key, (char *)&x_pkt->exten[1]);
1140		if (mac_size > 0)
1141			pkt_len += mac_size + 4;
1142	}
1143	return pkt_len;
1144}
1145
1146
1147int
1148handle_pkt(
1149	int		rpktl,
1150	struct pkt *	rpkt,
1151	sockaddr_u *	host,
1152	const char *	hostname
1153	)
1154{
1155	char		disptxt[32];
1156	const char *	addrtxt;
1157	struct timeval	tv_dst;
1158	int		cnt;
1159	int		sw_case;
1160	int		digits;
1161	int		stratum;
1162	char *		ref;
1163	char *		ts_str;
1164	const char *	leaptxt;
1165	double		offset;
1166	double		precision;
1167	double		synch_distance;
1168	char *		p_SNTP_PRETEND_TIME;
1169	time_t		pretend_time;
1170#if SIZEOF_TIME_T == 8
1171	long long	ll;
1172#else
1173	long		l;
1174#endif
1175
1176	ts_str = NULL;
1177
1178	if (rpktl > 0)
1179		sw_case = 1;
1180	else
1181		sw_case = rpktl;
1182
1183	switch (sw_case) {
1184
1185	case SERVER_UNUSEABLE:
1186		return -1;
1187		break;
1188
1189	case PACKET_UNUSEABLE:
1190		break;
1191
1192	case SERVER_AUTH_FAIL:
1193		break;
1194
1195	case KOD_DEMOBILIZE:
1196		/* Received a DENY or RESTR KOD packet */
1197		addrtxt = stoa(host);
1198		ref = (char *)&rpkt->refid;
1199		add_entry(addrtxt, ref);
1200		msyslog(LOG_WARNING, "KOD code %c%c%c%c from %s %s",
1201			ref[0], ref[1], ref[2], ref[3], addrtxt, hostname);
1202		break;
1203
1204	case KOD_RATE:
1205		/*
1206		** Hmm...
1207		** We should probably call add_entry() with an
1208		** expiration timestamp of several seconds in the future,
1209		** and back-off even more if we get more RATE responses.
1210		*/
1211		break;
1212
1213	case 1:
1214		TRACE(3, ("handle_pkt: %d bytes from %s %s\n",
1215			  rpktl, stoa(host), hostname));
1216
1217		gettimeofday_cached(base, &tv_dst);
1218
1219		p_SNTP_PRETEND_TIME = getenv("SNTP_PRETEND_TIME");
1220		if (p_SNTP_PRETEND_TIME) {
1221			pretend_time = 0;
1222#if SIZEOF_TIME_T == 4
1223			if (1 == sscanf(p_SNTP_PRETEND_TIME, "%ld", &l))
1224				pretend_time = (time_t)l;
1225#elif SIZEOF_TIME_T == 8
1226			if (1 == sscanf(p_SNTP_PRETEND_TIME, "%lld", &ll))
1227				pretend_time = (time_t)ll;
1228#else
1229# include "GRONK: unexpected value for SIZEOF_TIME_T"
1230#endif
1231			if (0 != pretend_time)
1232				tv_dst.tv_sec = pretend_time;
1233		}
1234
1235		offset_calculation(rpkt, rpktl, &tv_dst, &offset,
1236				   &precision, &synch_distance);
1237		time_derived = TRUE;
1238
1239		for (digits = 0; (precision *= 10.) < 1.; ++digits)
1240			/* empty */ ;
1241		if (digits > 6)
1242			digits = 6;
1243
1244		ts_str = tv_to_str(&tv_dst);
1245		stratum = rpkt->stratum;
1246		if (0 == stratum)
1247				stratum = 16;
1248
1249		if (synch_distance > 0.) {
1250			cnt = snprintf(disptxt, sizeof(disptxt),
1251				       " +/- %f", synch_distance);
1252			if ((size_t)cnt >= sizeof(disptxt))
1253				snprintf(disptxt, sizeof(disptxt),
1254					 "ERROR %d >= %d", cnt,
1255					 (int)sizeof(disptxt));
1256		} else {
1257			disptxt[0] = '\0';
1258		}
1259
1260		switch (PKT_LEAP(rpkt->li_vn_mode)) {
1261		    case LEAP_NOWARNING:
1262		    	leaptxt = "no-leap";
1263			break;
1264		    case LEAP_ADDSECOND:
1265		    	leaptxt = "add-leap";
1266			break;
1267		    case LEAP_DELSECOND:
1268		    	leaptxt = "del-leap";
1269			break;
1270		    case LEAP_NOTINSYNC:
1271		    	leaptxt = "unsync";
1272			break;
1273		    default:
1274		    	leaptxt = "LEAP-ERROR";
1275			break;
1276		}
1277
1278		msyslog(LOG_INFO, "%s %+.*f%s %s s%d %s%s", ts_str,
1279			digits, offset, disptxt,
1280			hostnameaddr(hostname, host), stratum,
1281			leaptxt,
1282			(time_adjusted)
1283			    ? " [excess]"
1284			    : "");
1285		free(ts_str);
1286
1287		if (p_SNTP_PRETEND_TIME)
1288			return 0;
1289
1290		if (!time_adjusted &&
1291		    (ENABLED_OPT(STEP) || ENABLED_OPT(SLEW)))
1292			return set_time(offset);
1293
1294		return EX_OK;
1295	}
1296
1297	return 1;
1298}
1299
1300
1301void
1302offset_calculation(
1303	struct pkt *rpkt,
1304	int rpktl,
1305	struct timeval *tv_dst,
1306	double *offset,
1307	double *precision,
1308	double *synch_distance
1309	)
1310{
1311	l_fp p_rec, p_xmt, p_ref, p_org, tmp, dst;
1312	u_fp p_rdly, p_rdsp;
1313	double t21, t34, delta;
1314
1315	/* Convert timestamps from network to host byte order */
1316	p_rdly = NTOHS_FP(rpkt->rootdelay);
1317	p_rdsp = NTOHS_FP(rpkt->rootdisp);
1318	NTOHL_FP(&rpkt->reftime, &p_ref);
1319	NTOHL_FP(&rpkt->org, &p_org);
1320	NTOHL_FP(&rpkt->rec, &p_rec);
1321	NTOHL_FP(&rpkt->xmt, &p_xmt);
1322
1323	*precision = LOGTOD(rpkt->precision);
1324
1325	TRACE(3, ("offset_calculation: LOGTOD(rpkt->precision): %f\n", *precision));
1326
1327	/* Compute offset etc. */
1328	tmp = p_rec;
1329	L_SUB(&tmp, &p_org);
1330	LFPTOD(&tmp, t21);
1331	TVTOTS(tv_dst, &dst);
1332	dst.l_ui += JAN_1970;
1333	tmp = p_xmt;
1334	L_SUB(&tmp, &dst);
1335	LFPTOD(&tmp, t34);
1336	*offset = (t21 + t34) / 2.;
1337	delta = t21 - t34;
1338
1339	// synch_distance is:
1340	// (peer->delay + peer->rootdelay) / 2 + peer->disp
1341	// + peer->rootdisp + clock_phi * (current_time - peer->update)
1342	// + peer->jitter;
1343	//
1344	// and peer->delay = fabs(peer->offset - p_offset) * 2;
1345	// and peer->offset needs history, so we're left with
1346	// p_offset = (t21 + t34) / 2.;
1347	// peer->disp = 0; (we have no history to augment this)
1348	// clock_phi = 15e-6;
1349	// peer->jitter = LOGTOD(sys_precision); (we have no history to augment this)
1350	// and ntp_proto.c:set_sys_tick_precision() should get us sys_precision.
1351	//
1352	// so our answer seems to be:
1353	//
1354	// (fabs(t21 + t34) + peer->rootdelay) / 3.
1355	// + 0 (peer->disp)
1356	// + peer->rootdisp
1357	// + 15e-6 (clock_phi)
1358	// + LOGTOD(sys_precision)
1359
1360	INSIST( FPTOD(p_rdly) >= 0. );
1361#if 1
1362	*synch_distance = (fabs(t21 + t34) + FPTOD(p_rdly)) / 3.
1363		+ 0.
1364		+ FPTOD(p_rdsp)
1365		+ 15e-6
1366		+ 0.	/* LOGTOD(sys_precision) when we can get it */
1367		;
1368	INSIST( *synch_distance >= 0. );
1369#else
1370	*synch_distance = (FPTOD(p_rdly) + FPTOD(p_rdsp))/2.0;
1371#endif
1372
1373#ifdef DEBUG
1374	if (debug > 3) {
1375		printf("sntp rootdelay: %f\n", FPTOD(p_rdly));
1376		printf("sntp rootdisp: %f\n", FPTOD(p_rdsp));
1377		printf("sntp syncdist: %f\n", *synch_distance);
1378
1379		pkt_output(rpkt, rpktl, stdout);
1380
1381		printf("sntp offset_calculation: rpkt->reftime:\n");
1382		l_fp_output(&p_ref, stdout);
1383		printf("sntp offset_calculation: rpkt->org:\n");
1384		l_fp_output(&p_org, stdout);
1385		printf("sntp offset_calculation: rpkt->rec:\n");
1386		l_fp_output(&p_rec, stdout);
1387		printf("sntp offset_calculation: rpkt->xmt:\n");
1388		l_fp_output(&p_xmt, stdout);
1389	}
1390#endif
1391
1392	TRACE(3, ("sntp offset_calculation:\trec - org t21: %.6f\n"
1393		  "\txmt - dst t34: %.6f\tdelta: %.6f\toffset: %.6f\n",
1394		  t21, t34, delta, *offset));
1395
1396	return;
1397}
1398
1399
1400
1401/* Compute the 8 bits for li_vn_mode */
1402void
1403set_li_vn_mode (
1404	struct pkt *spkt,
1405	char leap,
1406	char version,
1407	char mode
1408	)
1409{
1410	if (leap > 3) {
1411		msyslog(LOG_DEBUG, "set_li_vn_mode: leap > 3, using max. 3");
1412		leap = 3;
1413	}
1414
1415	if ((unsigned char)version > 7) {
1416		msyslog(LOG_DEBUG, "set_li_vn_mode: version < 0 or > 7, using 4");
1417		version = 4;
1418	}
1419
1420	if (mode > 7) {
1421		msyslog(LOG_DEBUG, "set_li_vn_mode: mode > 7, using client mode 3");
1422		mode = 3;
1423	}
1424
1425	spkt->li_vn_mode  = leap << 6;
1426	spkt->li_vn_mode |= version << 3;
1427	spkt->li_vn_mode |= mode;
1428}
1429
1430
1431/*
1432** set_time applies 'offset' to the local clock.
1433*/
1434int
1435set_time(
1436	double offset
1437	)
1438{
1439	int rc;
1440
1441	if (time_adjusted)
1442		return EX_OK;
1443
1444	/*
1445	** If we can step but we cannot slew, then step.
1446	** If we can step or slew and and |offset| > steplimit, then step.
1447	*/
1448	if (ENABLED_OPT(STEP) &&
1449	    (   !ENABLED_OPT(SLEW)
1450	     || (ENABLED_OPT(SLEW) && (fabs(offset) > steplimit))
1451	    )) {
1452		rc = step_systime(offset);
1453
1454		/* If there was a problem, can we rely on errno? */
1455		if (1 == rc)
1456			time_adjusted = TRUE;
1457		return (time_adjusted)
1458			   ? EX_OK
1459			   : 1;
1460		/*
1461		** In case of error, what should we use?
1462		** EX_UNAVAILABLE?
1463		** EX_OSERR?
1464		** EX_NOPERM?
1465		*/
1466	}
1467
1468	if (ENABLED_OPT(SLEW)) {
1469		rc = adj_systime(offset);
1470
1471		/* If there was a problem, can we rely on errno? */
1472		if (1 == rc)
1473			time_adjusted = TRUE;
1474		return (time_adjusted)
1475			   ? EX_OK
1476			   : 1;
1477		/*
1478		** In case of error, what should we use?
1479		** EX_UNAVAILABLE?
1480		** EX_OSERR?
1481		** EX_NOPERM?
1482		*/
1483	}
1484
1485	return EX_SOFTWARE;
1486}
1487
1488
1489int
1490libevent_version_ok(void)
1491{
1492	ev_uint32_t v_compile_maj;
1493	ev_uint32_t v_run_maj;
1494
1495	v_compile_maj = LIBEVENT_VERSION_NUMBER & 0xffff0000;
1496	v_run_maj = event_get_version_number() & 0xffff0000;
1497	if (v_compile_maj != v_run_maj) {
1498		fprintf(stderr,
1499			"Incompatible libevent versions: have %s, built with %s\n",
1500			event_get_version(),
1501			LIBEVENT_VERSION);
1502		return 0;
1503	}
1504	return 1;
1505}
1506
1507/*
1508 * gettimeofday_cached()
1509 *
1510 * Clones the event_base_gettimeofday_cached() interface but ensures the
1511 * times are always on the gettimeofday() 1970 scale.  Older libevent 2
1512 * sometimes used gettimeofday(), sometimes the since-system-start
1513 * clock_gettime(CLOCK_MONOTONIC), depending on the platform.
1514 *
1515 * It is not cleanly possible to tell which timescale older libevent is
1516 * using.
1517 *
1518 * The strategy involves 1 hour thresholds chosen to be far longer than
1519 * the duration of a round of libevent callbacks, which share a cached
1520 * start-of-round time.  First compare the last cached time with the
1521 * current gettimeofday() time.  If they are within one hour, libevent
1522 * is using the proper timescale so leave the offset 0.  Otherwise,
1523 * compare libevent's cached time and the current time on the monotonic
1524 * scale.  If they are within an hour, libevent is using the monotonic
1525 * scale so calculate the offset to add to such times to bring them to
1526 * gettimeofday()'s scale.
1527 */
1528int
1529gettimeofday_cached(
1530	struct event_base *	b,
1531	struct timeval *	caller_tv
1532	)
1533{
1534#if defined(_EVENT_HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
1535	static struct event_base *	cached_b;
1536	static struct timeval		cached;
1537	static struct timeval		adj_cached;
1538	static struct timeval		offset;
1539	static int			offset_ready;
1540	struct timeval			latest;
1541	struct timeval			systemt;
1542	struct timespec			ts;
1543	struct timeval			mono;
1544	struct timeval			diff;
1545	int				cgt_rc;
1546	int				gtod_rc;
1547
1548	event_base_gettimeofday_cached(b, &latest);
1549	if (b == cached_b &&
1550	    !memcmp(&latest, &cached, sizeof(latest))) {
1551		*caller_tv = adj_cached;
1552		return 0;
1553	}
1554	cached = latest;
1555	cached_b = b;
1556	if (!offset_ready) {
1557		cgt_rc = clock_gettime(CLOCK_MONOTONIC, &ts);
1558		gtod_rc = gettimeofday(&systemt, NULL);
1559		if (0 != gtod_rc) {
1560			msyslog(LOG_ERR,
1561				"%s: gettimeofday() error %m",
1562				progname);
1563			exit(1);
1564		}
1565		diff = sub_tval(systemt, latest);
1566		if (debug > 1)
1567			printf("system minus cached %+ld.%06ld\n",
1568			       (long)diff.tv_sec, (long)diff.tv_usec);
1569		if (0 != cgt_rc || labs((long)diff.tv_sec) < 3600) {
1570			/*
1571			 * Either use_monotonic == 0, or this libevent
1572			 * has been repaired.  Leave offset at zero.
1573			 */
1574		} else {
1575			mono.tv_sec = ts.tv_sec;
1576			mono.tv_usec = ts.tv_nsec / 1000;
1577			diff = sub_tval(latest, mono);
1578			if (debug > 1)
1579				printf("cached minus monotonic %+ld.%06ld\n",
1580				       (long)diff.tv_sec, (long)diff.tv_usec);
1581			if (labs((long)diff.tv_sec) < 3600) {
1582				/* older libevent2 using monotonic */
1583				offset = sub_tval(systemt, mono);
1584				TRACE(1, ("%s: Offsetting libevent CLOCK_MONOTONIC times  by %+ld.%06ld\n",
1585					 "gettimeofday_cached",
1586					 (long)offset.tv_sec,
1587					 (long)offset.tv_usec));
1588			}
1589		}
1590		offset_ready = TRUE;
1591	}
1592	adj_cached = add_tval(cached, offset);
1593	*caller_tv = adj_cached;
1594
1595	return 0;
1596#else
1597	return event_base_gettimeofday_cached(b, caller_tv);
1598#endif
1599}
1600
1601