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Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001/*
2 * NTP client/server, based on OpenNTPD 3.9p1
3 *
Adam Tkac4bf88d92015-01-04 17:46:08 +01004 * Busybox port author: Adam Tkac (C) 2009 <vonsch@gmail.com>
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01005 *
Adam Tkac4bf88d92015-01-04 17:46:08 +01006 * OpenNTPd 3.9p1 copyright holders:
7 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
8 * Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
9 *
10 * OpenNTPd code is licensed under ISC-style licence:
11 *
12 * Permission to use, copy, modify, and distribute this software for any
13 * purpose with or without fee is hereby granted, provided that the above
14 * copyright notice and this permission notice appear in all copies.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
17 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
19 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
20 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
21 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
22 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
23 ***********************************************************************
Denys Vlasenkodd6673b2010-01-01 16:46:17 +010024 *
25 * Parts of OpenNTPD clock syncronization code is replaced by
Adam Tkac4bf88d92015-01-04 17:46:08 +010026 * code which is based on ntp-4.2.6, which carries the following
Denys Vlasenkodd6673b2010-01-01 16:46:17 +010027 * copyright notice:
28 *
Adam Tkac4bf88d92015-01-04 17:46:08 +010029 * Copyright (c) University of Delaware 1992-2009
30 *
31 * Permission to use, copy, modify, and distribute this software and
32 * its documentation for any purpose with or without fee is hereby
33 * granted, provided that the above copyright notice appears in all
34 * copies and that both the copyright notice and this permission
35 * notice appear in supporting documentation, and that the name
36 * University of Delaware not be used in advertising or publicity
37 * pertaining to distribution of the software without specific,
38 * written prior permission. The University of Delaware makes no
39 * representations about the suitability this software for any
40 * purpose. It is provided "as is" without express or implied warranty.
Denys Vlasenkodd6673b2010-01-01 16:46:17 +010041 ***********************************************************************
42 */
Denys Vlasenko47367e12016-11-23 09:05:14 +010043//config:config NTPD
Denys Vlasenko4eed2c62017-07-18 22:01:24 +020044//config: bool "ntpd (17 kb)"
Denys Vlasenko47367e12016-11-23 09:05:14 +010045//config: default y
46//config: select PLATFORM_LINUX
47//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020048//config: The NTP client/server daemon.
Denys Vlasenko47367e12016-11-23 09:05:14 +010049//config:
50//config:config FEATURE_NTPD_SERVER
51//config: bool "Make ntpd usable as a NTP server"
52//config: default y
53//config: depends on NTPD
54//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020055//config: Make ntpd usable as a NTP server. If you disable this option
56//config: ntpd will be usable only as a NTP client.
Denys Vlasenko47367e12016-11-23 09:05:14 +010057//config:
58//config:config FEATURE_NTPD_CONF
59//config: bool "Make ntpd understand /etc/ntp.conf"
60//config: default y
61//config: depends on NTPD
62//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020063//config: Make ntpd look in /etc/ntp.conf for peers. Only "server address"
64//config: is supported.
Denys Vlasenko47367e12016-11-23 09:05:14 +010065
66//applet:IF_NTPD(APPLET(ntpd, BB_DIR_USR_SBIN, BB_SUID_DROP))
67
68//kbuild:lib-$(CONFIG_NTPD) += ntpd.o
Pere Orga5bc8c002011-04-11 03:29:49 +020069
70//usage:#define ntpd_trivial_usage
Denys Vlasenko278842d2014-07-15 15:06:54 +020071//usage: "[-dnqNw"IF_FEATURE_NTPD_SERVER("l -I IFACE")"] [-S PROG] [-p PEER]..."
Pere Orga5bc8c002011-04-11 03:29:49 +020072//usage:#define ntpd_full_usage "\n\n"
73//usage: "NTP client/server\n"
Pere Orga5bc8c002011-04-11 03:29:49 +020074//usage: "\n -d Verbose"
75//usage: "\n -n Do not daemonize"
76//usage: "\n -q Quit after clock is set"
77//usage: "\n -N Run at high priority"
78//usage: "\n -w Do not set time (only query peers), implies -n"
Pere Orga5bc8c002011-04-11 03:29:49 +020079//usage: "\n -S PROG Run PROG after stepping time, stratum change, and every 11 mins"
80//usage: "\n -p PEER Obtain time from PEER (may be repeated)"
Denys Vlasenko504fe452014-03-23 15:06:38 +010081//usage: IF_FEATURE_NTPD_CONF(
Denys Vlasenko3c31b092015-03-05 14:04:44 +010082//usage: "\n If -p is not given, 'server HOST' lines"
83//usage: "\n from /etc/ntp.conf are used"
Denys Vlasenko504fe452014-03-23 15:06:38 +010084//usage: )
Denys Vlasenko3aef8142015-03-02 20:59:13 +010085//usage: IF_FEATURE_NTPD_SERVER(
86//usage: "\n -l Also run as server on port 123"
87//usage: "\n -I IFACE Bind server to IFACE, implies -l"
88//usage: )
Denys Vlasenko504fe452014-03-23 15:06:38 +010089
90// -l and -p options are not compatible with "standard" ntpd:
91// it has them as "-l logfile" and "-p pidfile".
92// -S and -w are not compat either, "standard" ntpd has no such opts.
Pere Orga5bc8c002011-04-11 03:29:49 +020093
Denys Vlasenkodd6673b2010-01-01 16:46:17 +010094#include "libbb.h"
95#include <math.h>
96#include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
Mike Frysingerc5fe9f72012-07-05 23:19:09 -040097#include <sys/resource.h> /* setpriority */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +010098#include <sys/timex.h>
99#ifndef IPTOS_LOWDELAY
100# define IPTOS_LOWDELAY 0x10
101#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100102
103
Denys Vlasenkobfc2a322010-01-01 18:12:06 +0100104/* Verbosity control (max level of -dddd options accepted).
Denys Vlasenkoa14958c2013-12-04 16:32:09 +0100105 * max 6 is very talkative (and bloated). 3 is non-bloated,
Denys Vlasenkobfc2a322010-01-01 18:12:06 +0100106 * production level setting.
107 */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +0100108#define MAX_VERBOSE 3
Denys Vlasenkobfc2a322010-01-01 18:12:06 +0100109
110
Denys Vlasenko65d722b2010-01-11 02:14:04 +0100111/* High-level description of the algorithm:
112 *
113 * We start running with very small poll_exp, BURSTPOLL,
Leonid Lisovskiy894ef602010-10-20 22:36:51 +0200114 * in order to quickly accumulate INITIAL_SAMPLES datapoints
Denys Vlasenko65d722b2010-01-11 02:14:04 +0100115 * for each peer. Then, time is stepped if the offset is larger
116 * than STEP_THRESHOLD, otherwise it isn't; anyway, we enlarge
117 * poll_exp to MINPOLL and enter frequency measurement step:
118 * we collect new datapoints but ignore them for WATCH_THRESHOLD
119 * seconds. After WATCH_THRESHOLD seconds we look at accumulated
120 * offset and estimate frequency drift.
121 *
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100122 * (frequency measurement step seems to not be strictly needed,
123 * it is conditionally disabled with USING_INITIAL_FREQ_ESTIMATION
124 * define set to 0)
125 *
Denys Vlasenko65d722b2010-01-11 02:14:04 +0100126 * After this, we enter "steady state": we collect a datapoint,
127 * we select the best peer, if this datapoint is not a new one
128 * (IOW: if this datapoint isn't for selected peer), sleep
129 * and collect another one; otherwise, use its offset to update
130 * frequency drift, if offset is somewhat large, reduce poll_exp,
131 * otherwise increase poll_exp.
132 *
133 * If offset is larger than STEP_THRESHOLD, which shouldn't normally
134 * happen, we assume that something "bad" happened (computer
135 * was hibernated, someone set totally wrong date, etc),
136 * then the time is stepped, all datapoints are discarded,
137 * and we go back to steady state.
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +0100138 *
139 * Made some changes to speed up re-syncing after our clock goes bad
140 * (tested with suspending my laptop):
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100141 * - if largish offset (>= STEP_THRESHOLD == 1 sec) is seen
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +0100142 * from a peer, schedule next query for this peer soon
143 * without drastically lowering poll interval for everybody.
144 * This makes us collect enough data for step much faster:
145 * e.g. at poll = 10 (1024 secs), step was done within 5 minutes
146 * after first reply which indicated that our clock is 14 seconds off.
147 * - on step, do not discard d_dispersion data of the existing datapoints,
148 * do not clear reachable_bits. This prevents discarding first ~8
149 * datapoints after the step.
Denys Vlasenko65d722b2010-01-11 02:14:04 +0100150 */
151
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +0100152#define INITIAL_SAMPLES 4 /* how many samples do we want for init */
153#define BAD_DELAY_GROWTH 4 /* drop packet if its delay grew by more than this */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100154
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200155#define RETRY_INTERVAL 32 /* on send/recv error, retry in N secs (need to be power of 2) */
156#define NOREPLY_INTERVAL 512 /* sent, but got no reply: cap next query by this many seconds */
157#define RESPONSE_INTERVAL 16 /* wait for reply up to N secs */
Natanael Copab62ea342017-01-06 16:18:45 +0100158#define HOSTNAME_INTERVAL 5 /* hostname lookup failed. Wait N secs for next try */
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100159
160/* Step threshold (sec). std ntpd uses 0.128.
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100161 */
162#define STEP_THRESHOLD 1
163/* Slew threshold (sec): adjtimex() won't accept offsets larger than this.
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200164 * Using exact power of 2 (1/8) results in smaller code
165 */
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100166#define SLEW_THRESHOLD 0.125
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200167/* Stepout threshold (sec). std ntpd uses 900 (11 mins (!)) */
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100168#define WATCH_THRESHOLD 128
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100169/* NB: set WATCH_THRESHOLD to ~60 when debugging to save time) */
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100170//UNUSED: #define PANIC_THRESHOLD 1000 /* panic threshold (sec) */
Denys Vlasenko12628b72010-01-11 01:31:59 +0100171
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200172/*
173 * If we got |offset| > BIGOFF from a peer, cap next query interval
174 * for this peer by this many seconds:
175 */
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100176#define BIGOFF STEP_THRESHOLD
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200177#define BIGOFF_INTERVAL (1 << 7) /* 128 s */
178
Denys Vlasenko12628b72010-01-11 01:31:59 +0100179#define FREQ_TOLERANCE 0.000015 /* frequency tolerance (15 PPM) */
Denys Vlasenkofb132e42010-10-29 11:46:52 +0200180#define BURSTPOLL 0 /* initial poll */
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100181#define MINPOLL 5 /* minimum poll interval. std ntpd uses 6 (6: 64 sec) */
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200182/*
Miroslav Lichvarb434ce72014-10-02 17:18:43 +0200183 * If offset > discipline_jitter * POLLADJ_GATE, and poll interval is > 2^BIGPOLL,
184 * then it is decreased _at once_. (If <= 2^BIGPOLL, it will be decreased _eventually_).
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +0100185 */
Miroslav Lichvarb434ce72014-10-02 17:18:43 +0200186#define BIGPOLL 9 /* 2^9 sec ~= 8.5 min */
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100187#define MAXPOLL 12 /* maximum poll interval (12: 1.1h, 17: 36.4h). std ntpd uses 17 */
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200188/*
189 * Actively lower poll when we see such big offsets.
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100190 * With SLEW_THRESHOLD = 0.125, it means we try to sync more aggressively
Denys Vlasenkod3fe9602014-09-27 22:56:09 +0200191 * if offset increases over ~0.04 sec
192 */
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100193//#define POLLDOWN_OFFSET (SLEW_THRESHOLD / 3)
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100194#define MINDISP 0.01 /* minimum dispersion (sec) */
195#define MAXDISP 16 /* maximum dispersion (sec) */
Denys Vlasenko12628b72010-01-11 01:31:59 +0100196#define MAXSTRAT 16 /* maximum stratum (infinity metric) */
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100197#define MAXDIST 1 /* distance threshold (sec) */
Denys Vlasenko12628b72010-01-11 01:31:59 +0100198#define MIN_SELECTED 1 /* minimum intersection survivors */
199#define MIN_CLUSTERED 3 /* minimum cluster survivors */
200
201#define MAXDRIFT 0.000500 /* frequency drift we can correct (500 PPM) */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100202
203/* Poll-adjust threshold.
204 * When we see that offset is small enough compared to discipline jitter,
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +0100205 * we grow a counter: += MINPOLL. When counter goes over POLLADJ_LIMIT,
Denys Vlasenko61313112010-01-01 19:56:16 +0100206 * we poll_exp++. If offset isn't small, counter -= poll_exp*2,
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +0100207 * and when it goes below -POLLADJ_LIMIT, we poll_exp--.
208 * (Bumped from 30 to 40 since otherwise I often see poll_exp going *2* steps down)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100209 */
Denys Vlasenkofc4ebd02012-02-28 02:45:00 +0100210#define POLLADJ_LIMIT 40
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +0100211/* If offset < discipline_jitter * POLLADJ_GATE, then we decide to increase
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100212 * poll interval (we think we can't improve timekeeping
213 * by staying at smaller poll).
214 */
Denys Vlasenko61313112010-01-01 19:56:16 +0100215#define POLLADJ_GATE 4
Denys Vlasenko132b0442012-03-05 00:51:48 +0100216#define TIMECONST_HACK_GATE 2
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100217/* Compromise Allan intercept (sec). doc uses 1500, std ntpd uses 512 */
Denys Vlasenko61313112010-01-01 19:56:16 +0100218#define ALLAN 512
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100219/* PLL loop gain */
Denys Vlasenko61313112010-01-01 19:56:16 +0100220#define PLL 65536
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100221/* FLL loop gain [why it depends on MAXPOLL??] */
Denys Vlasenko61313112010-01-01 19:56:16 +0100222#define FLL (MAXPOLL + 1)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100223/* Parameter averaging constant */
Denys Vlasenko61313112010-01-01 19:56:16 +0100224#define AVG 4
225
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100226
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100227enum {
228 NTP_VERSION = 4,
229 NTP_MAXSTRATUM = 15,
230
231 NTP_DIGESTSIZE = 16,
232 NTP_MSGSIZE_NOAUTH = 48,
233 NTP_MSGSIZE = (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE),
234
235 /* Status Masks */
236 MODE_MASK = (7 << 0),
237 VERSION_MASK = (7 << 3),
238 VERSION_SHIFT = 3,
239 LI_MASK = (3 << 6),
240
241 /* Leap Second Codes (high order two bits of m_status) */
242 LI_NOWARNING = (0 << 6), /* no warning */
243 LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
244 LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
245 LI_ALARM = (3 << 6), /* alarm condition */
246
247 /* Mode values */
248 MODE_RES0 = 0, /* reserved */
249 MODE_SYM_ACT = 1, /* symmetric active */
250 MODE_SYM_PAS = 2, /* symmetric passive */
251 MODE_CLIENT = 3, /* client */
252 MODE_SERVER = 4, /* server */
253 MODE_BROADCAST = 5, /* broadcast */
254 MODE_RES1 = 6, /* reserved for NTP control message */
255 MODE_RES2 = 7, /* reserved for private use */
256};
257
258//TODO: better base selection
259#define OFFSET_1900_1970 2208988800UL /* 1970 - 1900 in seconds */
260
261#define NUM_DATAPOINTS 8
262
263typedef struct {
264 uint32_t int_partl;
265 uint32_t fractionl;
266} l_fixedpt_t;
267
268typedef struct {
269 uint16_t int_parts;
270 uint16_t fractions;
271} s_fixedpt_t;
272
273typedef struct {
274 uint8_t m_status; /* status of local clock and leap info */
275 uint8_t m_stratum;
276 uint8_t m_ppoll; /* poll value */
277 int8_t m_precision_exp;
278 s_fixedpt_t m_rootdelay;
279 s_fixedpt_t m_rootdisp;
280 uint32_t m_refid;
281 l_fixedpt_t m_reftime;
282 l_fixedpt_t m_orgtime;
283 l_fixedpt_t m_rectime;
284 l_fixedpt_t m_xmttime;
285 uint32_t m_keyid;
286 uint8_t m_digest[NTP_DIGESTSIZE];
287} msg_t;
288
289typedef struct {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100290 double d_offset;
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100291 double d_recv_time;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100292 double d_dispersion;
293} datapoint_t;
294
295typedef struct {
296 len_and_sockaddr *p_lsa;
297 char *p_dotted;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100298 int p_fd;
299 int datapoint_idx;
300 uint32_t lastpkt_refid;
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +0100301 uint8_t lastpkt_status;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100302 uint8_t lastpkt_stratum;
Denys Vlasenko0b002812010-01-03 08:59:59 +0100303 uint8_t reachable_bits;
Denys Vlasenko982e87f2013-07-30 11:52:58 +0200304 /* when to send new query (if p_fd == -1)
305 * or when receive times out (if p_fd >= 0): */
Denys Vlasenko0b002812010-01-03 08:59:59 +0100306 double next_action_time;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100307 double p_xmttime;
Denys Vlasenkod531f932014-04-19 19:00:16 +0200308 double p_raw_delay;
309 /* p_raw_delay is set even by "high delay" packets */
310 /* lastpkt_delay isn't */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100311 double lastpkt_recv_time;
312 double lastpkt_delay;
313 double lastpkt_rootdelay;
314 double lastpkt_rootdisp;
315 /* produced by filter algorithm: */
316 double filter_offset;
317 double filter_dispersion;
318 double filter_jitter;
319 datapoint_t filter_datapoint[NUM_DATAPOINTS];
320 /* last sent packet: */
321 msg_t p_xmt_msg;
Denys Vlasenkoe4caf1d2016-06-06 02:26:49 +0200322 char p_hostname[1];
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100323} peer_t;
324
325
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100326#define USING_KERNEL_PLL_LOOP 1
327#define USING_INITIAL_FREQ_ESTIMATION 0
328
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100329enum {
330 OPT_n = (1 << 0),
331 OPT_q = (1 << 1),
332 OPT_N = (1 << 2),
333 OPT_x = (1 << 3),
334 /* Insert new options above this line. */
335 /* Non-compat options: */
Denys Vlasenko4168fdd2010-01-04 00:19:13 +0100336 OPT_w = (1 << 4),
337 OPT_p = (1 << 5),
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100338 OPT_S = (1 << 6),
339 OPT_l = (1 << 7) * ENABLE_FEATURE_NTPD_SERVER,
Denys Vlasenko278842d2014-07-15 15:06:54 +0200340 OPT_I = (1 << 8) * ENABLE_FEATURE_NTPD_SERVER,
Denys Vlasenko8e23faf2011-04-07 01:45:20 +0200341 /* We hijack some bits for other purposes */
Denys Vlasenko16c52a52012-02-23 14:28:47 +0100342 OPT_qq = (1 << 31),
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100343};
344
345struct globals {
Denys Vlasenko0b002812010-01-03 08:59:59 +0100346 double cur_time;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100347 /* total round trip delay to currently selected reference clock */
348 double rootdelay;
349 /* reference timestamp: time when the system clock was last set or corrected */
350 double reftime;
351 /* total dispersion to currently selected reference clock */
352 double rootdisp;
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100353
354 double last_script_run;
355 char *script_name;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100356 llist_t *ntp_peers;
357#if ENABLE_FEATURE_NTPD_SERVER
358 int listen_fd;
Denys Vlasenko278842d2014-07-15 15:06:54 +0200359 char *if_name;
Denys Vlasenko3e3a8d52012-04-01 16:31:04 +0200360# define G_listen_fd (G.listen_fd)
361#else
362# define G_listen_fd (-1)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100363#endif
364 unsigned verbose;
365 unsigned peer_cnt;
366 /* refid: 32-bit code identifying the particular server or reference clock
Denys Vlasenko74584b82012-03-02 01:22:40 +0100367 * in stratum 0 packets this is a four-character ASCII string,
368 * called the kiss code, used for debugging and monitoring
369 * in stratum 1 packets this is a four-character ASCII string
370 * assigned to the reference clock by IANA. Example: "GPS "
371 * in stratum 2+ packets, it's IPv4 address or 4 first bytes
372 * of MD5 hash of IPv6
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100373 */
374 uint32_t refid;
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +0100375 uint8_t ntp_status;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100376 /* precision is defined as the larger of the resolution and time to
377 * read the clock, in log2 units. For instance, the precision of a
378 * mains-frequency clock incrementing at 60 Hz is 16 ms, even when the
379 * system clock hardware representation is to the nanosecond.
380 *
Denys Vlasenko74584b82012-03-02 01:22:40 +0100381 * Delays, jitters of various kinds are clamped down to precision.
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100382 *
383 * If precision_sec is too large, discipline_jitter gets clamped to it
Denys Vlasenko74584b82012-03-02 01:22:40 +0100384 * and if offset is smaller than discipline_jitter * POLLADJ_GATE, poll
385 * interval grows even though we really can benefit from staying at
386 * smaller one, collecting non-lagged datapoits and correcting offset.
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100387 * (Lagged datapoits exist when poll_exp is large but we still have
388 * systematic offset error - the time distance between datapoints
Denys Vlasenko74584b82012-03-02 01:22:40 +0100389 * is significant and older datapoints have smaller offsets.
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100390 * This makes our offset estimation a bit smaller than reality)
391 * Due to this effect, setting G_precision_sec close to
392 * STEP_THRESHOLD isn't such a good idea - offsets may grow
393 * too big and we will step. I observed it with -6.
394 *
Denys Vlasenko74584b82012-03-02 01:22:40 +0100395 * OTOH, setting precision_sec far too small would result in futile
Denys Vlasenko10ad6222017-04-17 16:13:32 +0200396 * attempts to synchronize to an unachievable precision.
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100397 *
398 * -6 is 1/64 sec, -7 is 1/128 sec and so on.
Denys Vlasenko74584b82012-03-02 01:22:40 +0100399 * -8 is 1/256 ~= 0.003906 (worked well for me --vda)
400 * -9 is 1/512 ~= 0.001953 (let's try this for some time)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100401 */
Denys Vlasenko74584b82012-03-02 01:22:40 +0100402#define G_precision_exp -9
403 /*
404 * G_precision_exp is used only for construction outgoing packets.
405 * It's ok to set G_precision_sec to a slightly different value
406 * (One which is "nicer looking" in logs).
407 * Exact value would be (1.0 / (1 << (- G_precision_exp))):
408 */
409#define G_precision_sec 0.002
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100410 uint8_t stratum;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100411
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100412#define STATE_NSET 0 /* initial state, "nothing is set" */
413//#define STATE_FSET 1 /* frequency set from file */
Denys Vlasenko6c46eed2013-12-04 17:12:11 +0100414//#define STATE_SPIK 2 /* spike detected */
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100415//#define STATE_FREQ 3 /* initial frequency */
416#define STATE_SYNC 4 /* clock synchronized (normal operation) */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100417 uint8_t discipline_state; // doc calls it c.state
418 uint8_t poll_exp; // s.poll
419 int polladj_count; // c.count
Denys Vlasenko61313112010-01-01 19:56:16 +0100420 long kernel_freq_drift;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +0100421 peer_t *last_update_peer;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100422 double last_update_offset; // c.last
Denys Vlasenko61313112010-01-01 19:56:16 +0100423 double last_update_recv_time; // s.t
424 double discipline_jitter; // c.jitter
Denys Vlasenko547ee792012-03-05 10:18:00 +0100425 /* Since we only compare it with ints, can simplify code
426 * by not making this variable floating point:
427 */
428 unsigned offset_to_jitter_ratio;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +0100429 //double cluster_offset; // s.offset
430 //double cluster_jitter; // s.jitter
Denys Vlasenko61313112010-01-01 19:56:16 +0100431#if !USING_KERNEL_PLL_LOOP
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100432 double discipline_freq_drift; // c.freq
Denys Vlasenko9b20adc2010-01-17 02:51:33 +0100433 /* Maybe conditionally calculate wander? it's used only for logging */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100434 double discipline_wander; // c.wander
Denys Vlasenko61313112010-01-01 19:56:16 +0100435#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100436};
437#define G (*ptr_to_globals)
438
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100439
Denys Vlasenkobfc2a322010-01-01 18:12:06 +0100440#define VERB1 if (MAX_VERBOSE && G.verbose)
441#define VERB2 if (MAX_VERBOSE >= 2 && G.verbose >= 2)
442#define VERB3 if (MAX_VERBOSE >= 3 && G.verbose >= 3)
443#define VERB4 if (MAX_VERBOSE >= 4 && G.verbose >= 4)
444#define VERB5 if (MAX_VERBOSE >= 5 && G.verbose >= 5)
Denys Vlasenkoa14958c2013-12-04 16:32:09 +0100445#define VERB6 if (MAX_VERBOSE >= 6 && G.verbose >= 6)
Denys Vlasenkobfc2a322010-01-01 18:12:06 +0100446
447
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100448static double LOG2D(int a)
449{
450 if (a < 0)
451 return 1.0 / (1UL << -a);
452 return 1UL << a;
453}
454static ALWAYS_INLINE double SQUARE(double x)
455{
456 return x * x;
457}
458static ALWAYS_INLINE double MAXD(double a, double b)
459{
460 if (a > b)
461 return a;
462 return b;
463}
464static ALWAYS_INLINE double MIND(double a, double b)
465{
466 if (a < b)
467 return a;
468 return b;
469}
Denys Vlasenkod498ff02010-01-03 21:06:27 +0100470static NOINLINE double my_SQRT(double X)
471{
472 union {
473 float f;
474 int32_t i;
475 } v;
476 double invsqrt;
477 double Xhalf = X * 0.5;
478
479 /* Fast and good approximation to 1/sqrt(X), black magic */
480 v.f = X;
481 /*v.i = 0x5f3759df - (v.i >> 1);*/
482 v.i = 0x5f375a86 - (v.i >> 1); /* - this constant is slightly better */
483 invsqrt = v.f; /* better than 0.2% accuracy */
484
485 /* Refining it using Newton's method: x1 = x0 - f(x0)/f'(x0)
486 * f(x) = 1/(x*x) - X (f==0 when x = 1/sqrt(X))
487 * f'(x) = -2/(x*x*x)
488 * f(x)/f'(x) = (X - 1/(x*x)) / (2/(x*x*x)) = X*x*x*x/2 - x/2
489 * x1 = x0 - (X*x0*x0*x0/2 - x0/2) = 1.5*x0 - X*x0*x0*x0/2 = x0*(1.5 - (X/2)*x0*x0)
490 */
491 invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); /* ~0.05% accuracy */
492 /* invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); 2nd iter: ~0.0001% accuracy */
493 /* With 4 iterations, more than half results will be exact,
494 * at 6th iterations result stabilizes with about 72% results exact.
495 * We are well satisfied with 0.05% accuracy.
496 */
497
498 return X * invsqrt; /* X * 1/sqrt(X) ~= sqrt(X) */
499}
500static ALWAYS_INLINE double SQRT(double X)
501{
502 /* If this arch doesn't use IEEE 754 floats, fall back to using libm */
503 if (sizeof(float) != 4)
504 return sqrt(X);
505
Denys Vlasenko2d3253d2010-01-03 21:52:46 +0100506 /* This avoids needing libm, saves about 0.5k on x86-32 */
Denys Vlasenkod498ff02010-01-03 21:06:27 +0100507 return my_SQRT(X);
508}
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100509
510static double
511gettime1900d(void)
512{
513 struct timeval tv;
514 gettimeofday(&tv, NULL); /* never fails */
Denys Vlasenko0b002812010-01-03 08:59:59 +0100515 G.cur_time = tv.tv_sec + (1.0e-6 * tv.tv_usec) + OFFSET_1900_1970;
516 return G.cur_time;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100517}
518
519static void
520d_to_tv(double d, struct timeval *tv)
521{
522 tv->tv_sec = (long)d;
523 tv->tv_usec = (d - tv->tv_sec) * 1000000;
524}
525
526static double
527lfp_to_d(l_fixedpt_t lfp)
528{
529 double ret;
530 lfp.int_partl = ntohl(lfp.int_partl);
531 lfp.fractionl = ntohl(lfp.fractionl);
532 ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX);
533 return ret;
534}
535static double
536sfp_to_d(s_fixedpt_t sfp)
537{
538 double ret;
539 sfp.int_parts = ntohs(sfp.int_parts);
540 sfp.fractions = ntohs(sfp.fractions);
541 ret = (double)sfp.int_parts + ((double)sfp.fractions / USHRT_MAX);
542 return ret;
543}
544#if ENABLE_FEATURE_NTPD_SERVER
545static l_fixedpt_t
546d_to_lfp(double d)
547{
548 l_fixedpt_t lfp;
549 lfp.int_partl = (uint32_t)d;
550 lfp.fractionl = (uint32_t)((d - lfp.int_partl) * UINT_MAX);
551 lfp.int_partl = htonl(lfp.int_partl);
552 lfp.fractionl = htonl(lfp.fractionl);
553 return lfp;
554}
555static s_fixedpt_t
556d_to_sfp(double d)
557{
558 s_fixedpt_t sfp;
559 sfp.int_parts = (uint16_t)d;
560 sfp.fractions = (uint16_t)((d - sfp.int_parts) * USHRT_MAX);
561 sfp.int_parts = htons(sfp.int_parts);
562 sfp.fractions = htons(sfp.fractions);
563 return sfp;
564}
565#endif
566
567static double
Denys Vlasenko0b002812010-01-03 08:59:59 +0100568dispersion(const datapoint_t *dp)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100569{
Denys Vlasenko0b002812010-01-03 08:59:59 +0100570 return dp->d_dispersion + FREQ_TOLERANCE * (G.cur_time - dp->d_recv_time);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100571}
572
573static double
Denys Vlasenko0b002812010-01-03 08:59:59 +0100574root_distance(peer_t *p)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100575{
576 /* The root synchronization distance is the maximum error due to
577 * all causes of the local clock relative to the primary server.
578 * It is defined as half the total delay plus total dispersion
579 * plus peer jitter.
580 */
581 return MAXD(MINDISP, p->lastpkt_rootdelay + p->lastpkt_delay) / 2
582 + p->lastpkt_rootdisp
583 + p->filter_dispersion
Denys Vlasenko0b002812010-01-03 08:59:59 +0100584 + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100585 + p->filter_jitter;
586}
587
588static void
589set_next(peer_t *p, unsigned t)
590{
Denys Vlasenko0b002812010-01-03 08:59:59 +0100591 p->next_action_time = G.cur_time + t;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100592}
593
594/*
595 * Peer clock filter and its helpers
596 */
597static void
Denys Vlasenko0b002812010-01-03 08:59:59 +0100598filter_datapoints(peer_t *p)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100599{
600 int i, idx;
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100601 double sum, wavg;
602 datapoint_t *fdp;
603
604#if 0
605/* Simulations have shown that use of *averaged* offset for p->filter_offset
606 * is in fact worse than simply using last received one: with large poll intervals
607 * (>= 2048) averaging code uses offset values which are outdated by hours,
608 * and time/frequency correction goes totally wrong when fed essentially bogus offsets.
609 */
Denys Vlasenkod9109e32010-01-02 00:36:43 +0100610 int got_newest;
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100611 double minoff, maxoff, w;
Denys Vlasenkod9109e32010-01-02 00:36:43 +0100612 double x = x; /* for compiler */
613 double oldest_off = oldest_off;
614 double oldest_age = oldest_age;
615 double newest_off = newest_off;
616 double newest_age = newest_age;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100617
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100618 fdp = p->filter_datapoint;
619
620 minoff = maxoff = fdp[0].d_offset;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100621 for (i = 1; i < NUM_DATAPOINTS; i++) {
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100622 if (minoff > fdp[i].d_offset)
623 minoff = fdp[i].d_offset;
624 if (maxoff < fdp[i].d_offset)
625 maxoff = fdp[i].d_offset;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100626 }
627
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100628 idx = p->datapoint_idx; /* most recent datapoint's index */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100629 /* Average offset:
630 * Drop two outliers and take weighted average of the rest:
631 * most_recent/2 + older1/4 + older2/8 ... + older5/32 + older6/32
632 * we use older6/32, not older6/64 since sum of weights should be 1:
633 * 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/32 = 1
634 */
635 wavg = 0;
636 w = 0.5;
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +0100637 /* n-1
638 * --- dispersion(i)
639 * filter_dispersion = \ -------------
640 * / (i+1)
641 * --- 2
642 * i=0
643 */
Denys Vlasenkod9109e32010-01-02 00:36:43 +0100644 got_newest = 0;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100645 sum = 0;
646 for (i = 0; i < NUM_DATAPOINTS; i++) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +0100647 VERB5 {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100648 bb_error_msg("datapoint[%d]: off:%f disp:%f(%f) age:%f%s",
649 i,
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100650 fdp[idx].d_offset,
651 fdp[idx].d_dispersion, dispersion(&fdp[idx]),
652 G.cur_time - fdp[idx].d_recv_time,
653 (minoff == fdp[idx].d_offset || maxoff == fdp[idx].d_offset)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100654 ? " (outlier by offset)" : ""
655 );
656 }
657
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100658 sum += dispersion(&fdp[idx]) / (2 << i);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100659
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100660 if (minoff == fdp[idx].d_offset) {
Denys Vlasenkoe4844b82010-01-01 21:59:49 +0100661 minoff -= 1; /* so that we don't match it ever again */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100662 } else
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100663 if (maxoff == fdp[idx].d_offset) {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100664 maxoff += 1;
665 } else {
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100666 oldest_off = fdp[idx].d_offset;
667 oldest_age = G.cur_time - fdp[idx].d_recv_time;
Denys Vlasenkod9109e32010-01-02 00:36:43 +0100668 if (!got_newest) {
669 got_newest = 1;
670 newest_off = oldest_off;
671 newest_age = oldest_age;
672 }
673 x = oldest_off * w;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100674 wavg += x;
675 w /= 2;
676 }
677
678 idx = (idx - 1) & (NUM_DATAPOINTS - 1);
679 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100680 p->filter_dispersion = sum;
Denys Vlasenkod9109e32010-01-02 00:36:43 +0100681 wavg += x; /* add another older6/64 to form older6/32 */
682 /* Fix systematic underestimation with large poll intervals.
683 * Imagine that we still have a bit of uncorrected drift,
684 * and poll interval is big (say, 100 sec). Offsets form a progression:
685 * 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 - 0.7 is most recent.
686 * The algorithm above drops 0.0 and 0.7 as outliers,
687 * and then we have this estimation, ~25% off from 0.7:
688 * 0.1/32 + 0.2/32 + 0.3/16 + 0.4/8 + 0.5/4 + 0.6/2 = 0.503125
689 */
Denys Vlasenko0b002812010-01-03 08:59:59 +0100690 x = oldest_age - newest_age;
691 if (x != 0) {
692 x = newest_age / x; /* in above example, 100 / (600 - 100) */
693 if (x < 1) { /* paranoia check */
694 x = (newest_off - oldest_off) * x; /* 0.5 * 100/500 = 0.1 */
695 wavg += x;
696 }
Denys Vlasenkod9109e32010-01-02 00:36:43 +0100697 }
698 p->filter_offset = wavg;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100699
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100700#else
701
702 fdp = p->filter_datapoint;
703 idx = p->datapoint_idx; /* most recent datapoint's index */
704
705 /* filter_offset: simply use the most recent value */
706 p->filter_offset = fdp[idx].d_offset;
707
708 /* n-1
709 * --- dispersion(i)
710 * filter_dispersion = \ -------------
711 * / (i+1)
712 * --- 2
713 * i=0
714 */
715 wavg = 0;
716 sum = 0;
717 for (i = 0; i < NUM_DATAPOINTS; i++) {
718 sum += dispersion(&fdp[idx]) / (2 << i);
719 wavg += fdp[idx].d_offset;
720 idx = (idx - 1) & (NUM_DATAPOINTS - 1);
721 }
722 wavg /= NUM_DATAPOINTS;
723 p->filter_dispersion = sum;
724#endif
725
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +0100726 /* +----- -----+ ^ 1/2
727 * | n-1 |
728 * | --- |
729 * | 1 \ 2 |
730 * filter_jitter = | --- * / (avg-offset_j) |
731 * | n --- |
732 * | j=0 |
733 * +----- -----+
734 * where n is the number of valid datapoints in the filter (n > 1);
735 * if filter_jitter < precision then filter_jitter = precision
736 */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100737 sum = 0;
738 for (i = 0; i < NUM_DATAPOINTS; i++) {
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100739 sum += SQUARE(wavg - fdp[i].d_offset);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100740 }
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +0100741 sum = SQRT(sum / NUM_DATAPOINTS);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100742 p->filter_jitter = sum > G_precision_sec ? sum : G_precision_sec;
743
Denys Vlasenkoa14958c2013-12-04 16:32:09 +0100744 VERB4 bb_error_msg("filter offset:%+f disp:%f jitter:%f",
Denys Vlasenkod98dc922012-03-08 03:27:49 +0100745 p->filter_offset,
Denys Vlasenkod9109e32010-01-02 00:36:43 +0100746 p->filter_dispersion,
747 p->filter_jitter);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100748}
749
750static void
Denys Vlasenko0b002812010-01-03 08:59:59 +0100751reset_peer_stats(peer_t *p, double offset)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100752{
753 int i;
Denys Vlasenkofc47fce2016-02-10 06:55:07 +0100754 bool small_ofs = fabs(offset) < STEP_THRESHOLD;
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100755
Denys Vlasenko777be102013-12-07 17:29:03 +0100756 /* Used to set p->filter_datapoint[i].d_dispersion = MAXDISP
Denys Vlasenko10ad6222017-04-17 16:13:32 +0200757 * and clear reachable bits, but this proved to be too aggressive:
Denys Vlasenkof37f2812016-03-04 07:06:53 +0100758 * after step (tested with suspending laptop for ~30 secs),
Denys Vlasenko777be102013-12-07 17:29:03 +0100759 * this caused all previous data to be considered invalid,
Denys Vlasenko1bfc4b82017-01-19 14:42:34 +0100760 * making us needing to collect full ~8 datapoints per peer
Denys Vlasenko777be102013-12-07 17:29:03 +0100761 * after step in order to start trusting them.
762 * In turn, this was making poll interval decrease even after
763 * step was done. (Poll interval decreases already before step
764 * in this scenario, because we see large offsets and end up with
765 * no good peer to select).
766 */
767
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100768 for (i = 0; i < NUM_DATAPOINTS; i++) {
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100769 if (small_ofs) {
Denys Vlasenkoeff6d592010-06-24 20:23:40 +0200770 p->filter_datapoint[i].d_recv_time += offset;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100771 if (p->filter_datapoint[i].d_offset != 0) {
Denys Vlasenkofc4ebd02012-02-28 02:45:00 +0100772 p->filter_datapoint[i].d_offset -= offset;
773 //bb_error_msg("p->filter_datapoint[%d].d_offset %f -> %f",
774 // i,
775 // p->filter_datapoint[i].d_offset + offset,
776 // p->filter_datapoint[i].d_offset);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100777 }
778 } else {
Denys Vlasenko0b002812010-01-03 08:59:59 +0100779 p->filter_datapoint[i].d_recv_time = G.cur_time;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100780 p->filter_datapoint[i].d_offset = 0;
Denys Vlasenko777be102013-12-07 17:29:03 +0100781 /*p->filter_datapoint[i].d_dispersion = MAXDISP;*/
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100782 }
783 }
Denys Vlasenko5b9a9102010-01-17 01:05:58 +0100784 if (small_ofs) {
Denys Vlasenkoeff6d592010-06-24 20:23:40 +0200785 p->lastpkt_recv_time += offset;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100786 } else {
Denys Vlasenko777be102013-12-07 17:29:03 +0100787 /*p->reachable_bits = 0;*/
Denys Vlasenko0b002812010-01-03 08:59:59 +0100788 p->lastpkt_recv_time = G.cur_time;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100789 }
Denys Vlasenko0b002812010-01-03 08:59:59 +0100790 filter_datapoints(p); /* recalc p->filter_xxx */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +0100791 VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100792}
793
Natanael Copab62ea342017-01-06 16:18:45 +0100794static len_and_sockaddr*
795resolve_peer_hostname(peer_t *p)
Denys Vlasenkoe4caf1d2016-06-06 02:26:49 +0200796{
Natanael Copab62ea342017-01-06 16:18:45 +0100797 len_and_sockaddr *lsa = host2sockaddr(p->p_hostname, 123);
798 if (lsa) {
799 free(p->p_lsa);
800 free(p->p_dotted);
801 p->p_lsa = lsa;
802 p->p_dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
Denys Vlasenko1bfc4b82017-01-19 14:42:34 +0100803 VERB1 if (strcmp(p->p_hostname, p->p_dotted) != 0)
804 bb_error_msg("'%s' is %s", p->p_hostname, p->p_dotted);
Natanael Copab62ea342017-01-06 16:18:45 +0100805 } else {
806 /* error message is emitted by host2sockaddr() */
807 set_next(p, HOSTNAME_INTERVAL);
Denys Vlasenkoe4caf1d2016-06-06 02:26:49 +0200808 }
Natanael Copab62ea342017-01-06 16:18:45 +0100809 return lsa;
Denys Vlasenkoe4caf1d2016-06-06 02:26:49 +0200810}
811
812static void
Denys Vlasenko504fe452014-03-23 15:06:38 +0100813add_peers(const char *s)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100814{
Denys Vlasenkof37f2812016-03-04 07:06:53 +0100815 llist_t *item;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100816 peer_t *p;
817
Denys Vlasenkoe4caf1d2016-06-06 02:26:49 +0200818 p = xzalloc(sizeof(*p) + strlen(s));
819 strcpy(p->p_hostname, s);
Natanael Copab62ea342017-01-06 16:18:45 +0100820 p->p_fd = -1;
821 p->p_xmt_msg.m_status = MODE_CLIENT | (NTP_VERSION << 3);
822 p->next_action_time = G.cur_time; /* = set_next(p, 0); */
823 reset_peer_stats(p, STEP_THRESHOLD);
Denys Vlasenkof37f2812016-03-04 07:06:53 +0100824
825 /* Names like N.<country2chars>.pool.ntp.org are randomly resolved
826 * to a pool of machines. Sometimes different N's resolve to the same IP.
827 * It is not useful to have two peers with same IP. We skip duplicates.
828 */
Natanael Copab62ea342017-01-06 16:18:45 +0100829 if (resolve_peer_hostname(p)) {
830 for (item = G.ntp_peers; item != NULL; item = item->link) {
831 peer_t *pp = (peer_t *) item->data;
832 if (pp->p_dotted && strcmp(p->p_dotted, pp->p_dotted) == 0) {
833 bb_error_msg("duplicate peer %s (%s)", s, p->p_dotted);
834 free(p->p_lsa);
835 free(p->p_dotted);
836 free(p);
837 return;
838 }
Denys Vlasenkof37f2812016-03-04 07:06:53 +0100839 }
840 }
841
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100842 llist_add_to(&G.ntp_peers, p);
843 G.peer_cnt++;
844}
845
846static int
847do_sendto(int fd,
848 const struct sockaddr *from, const struct sockaddr *to, socklen_t addrlen,
849 msg_t *msg, ssize_t len)
850{
851 ssize_t ret;
852
853 errno = 0;
854 if (!from) {
855 ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen);
856 } else {
857 ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
858 }
859 if (ret != len) {
860 bb_perror_msg("send failed");
861 return -1;
862 }
863 return 0;
864}
865
Denys Vlasenko0b002812010-01-03 08:59:59 +0100866static void
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100867send_query_to_peer(peer_t *p)
868{
Natanael Copab62ea342017-01-06 16:18:45 +0100869 if (!p->p_lsa) {
870 if (!resolve_peer_hostname(p))
871 return;
872 }
873
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +0100874 /* Why do we need to bind()?
875 * See what happens when we don't bind:
876 *
877 * socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
878 * setsockopt(3, SOL_IP, IP_TOS, [16], 4) = 0
879 * gettimeofday({1259071266, 327885}, NULL) = 0
880 * sendto(3, "xxx", 48, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("10.34.32.125")}, 16) = 48
881 * ^^^ we sent it from some source port picked by kernel.
882 * time(NULL) = 1259071266
883 * write(2, "ntpd: entering poll 15 secs\n", 28) = 28
884 * poll([{fd=3, events=POLLIN}], 1, 15000) = 1 ([{fd=3, revents=POLLIN}])
885 * recv(3, "yyy", 68, MSG_DONTWAIT) = 48
886 * ^^^ this recv will receive packets to any local port!
887 *
888 * Uncomment this and use strace to see it in action:
889 */
890#define PROBE_LOCAL_ADDR /* { len_and_sockaddr lsa; lsa.len = LSA_SIZEOF_SA; getsockname(p->query.fd, &lsa.u.sa, &lsa.len); } */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100891
892 if (p->p_fd == -1) {
893 int fd, family;
894 len_and_sockaddr *local_lsa;
895
896 family = p->p_lsa->u.sa.sa_family;
897 p->p_fd = fd = xsocket_type(&local_lsa, family, SOCK_DGRAM);
898 /* local_lsa has "null" address and port 0 now.
899 * bind() ensures we have a *particular port* selected by kernel
900 * and remembered in p->p_fd, thus later recv(p->p_fd)
901 * receives only packets sent to this port.
902 */
903 PROBE_LOCAL_ADDR
904 xbind(fd, &local_lsa->u.sa, local_lsa->len);
905 PROBE_LOCAL_ADDR
906#if ENABLE_FEATURE_IPV6
907 if (family == AF_INET)
908#endif
Denys Vlasenkoc52cbea2015-08-24 19:48:03 +0200909 setsockopt_int(fd, IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100910 free(local_lsa);
911 }
912
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +0100913 /* Emit message _before_ attempted send. Think of a very short
914 * roundtrip networks: we need to go back to recv loop ASAP,
915 * to reduce delay. Printing messages after send works against that.
916 */
917 VERB1 bb_error_msg("sending query to %s", p->p_dotted);
918
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100919 /*
920 * Send out a random 64-bit number as our transmit time. The NTP
921 * server will copy said number into the originate field on the
922 * response that it sends us. This is totally legal per the SNTP spec.
923 *
924 * The impact of this is two fold: we no longer send out the current
925 * system time for the world to see (which may aid an attacker), and
926 * it gives us a (not very secure) way of knowing that we're not
927 * getting spoofed by an attacker that can't capture our traffic
928 * but can spoof packets from the NTP server we're communicating with.
929 *
930 * Save the real transmit timestamp locally.
931 */
Denys Vlasenko0ed5f7a2014-03-05 18:58:15 +0100932 p->p_xmt_msg.m_xmttime.int_partl = rand();
933 p->p_xmt_msg.m_xmttime.fractionl = rand();
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100934 p->p_xmttime = gettime1900d();
935
Denys Vlasenko5a7e3372013-05-23 16:06:59 +0200936 /* Were doing it only if sendto worked, but
Denys Vlasenko5ffdd1d2013-05-22 18:16:34 +0200937 * loss of sync detection needs reachable_bits updated
938 * even if sending fails *locally*:
939 * "network is unreachable" because cable was pulled?
940 * We still need to declare "unsync" if this condition persists.
941 */
942 p->reachable_bits <<= 1;
943
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100944 if (do_sendto(p->p_fd, /*from:*/ NULL, /*to:*/ &p->p_lsa->u.sa, /*addrlen:*/ p->p_lsa->len,
945 &p->p_xmt_msg, NTP_MSGSIZE_NOAUTH) == -1
946 ) {
947 close(p->p_fd);
948 p->p_fd = -1;
Denys Vlasenko5a7e3372013-05-23 16:06:59 +0200949 /*
950 * We know that we sent nothing.
951 * We can retry *soon* without fearing
952 * that we are flooding the peer.
953 */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100954 set_next(p, RETRY_INTERVAL);
Denys Vlasenko0b002812010-01-03 08:59:59 +0100955 return;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100956 }
957
Denys Vlasenko0b002812010-01-03 08:59:59 +0100958 set_next(p, RESPONSE_INTERVAL);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +0100959}
960
961
Denys Vlasenko24928ff2010-01-25 19:30:16 +0100962/* Note that there is no provision to prevent several run_scripts
Denys Vlasenko5a7e3372013-05-23 16:06:59 +0200963 * to be started in quick succession. In fact, it happens rather often
Denys Vlasenko24928ff2010-01-25 19:30:16 +0100964 * if initial syncronization results in a step.
965 * You will see "step" and then "stratum" script runs, sometimes
966 * as close as only 0.002 seconds apart.
967 * Script should be ready to deal with this.
968 */
Denys Vlasenko12628b72010-01-11 01:31:59 +0100969static void run_script(const char *action, double offset)
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100970{
971 char *argv[3];
Denys Vlasenko12628b72010-01-11 01:31:59 +0100972 char *env1, *env2, *env3, *env4;
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100973
Denys Vlasenko07c59872013-05-22 18:18:51 +0200974 G.last_script_run = G.cur_time;
975
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100976 if (!G.script_name)
977 return;
978
979 argv[0] = (char*) G.script_name;
980 argv[1] = (char*) action;
981 argv[2] = NULL;
982
983 VERB1 bb_error_msg("executing '%s %s'", G.script_name, action);
984
Denys Vlasenkoae473352010-01-07 11:51:13 +0100985 env1 = xasprintf("%s=%u", "stratum", G.stratum);
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100986 putenv(env1);
Denys Vlasenkoae473352010-01-07 11:51:13 +0100987 env2 = xasprintf("%s=%ld", "freq_drift_ppm", G.kernel_freq_drift);
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100988 putenv(env2);
Denys Vlasenkoae473352010-01-07 11:51:13 +0100989 env3 = xasprintf("%s=%u", "poll_interval", 1 << G.poll_exp);
990 putenv(env3);
Denys Vlasenko12628b72010-01-11 01:31:59 +0100991 env4 = xasprintf("%s=%f", "offset", offset);
992 putenv(env4);
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100993 /* Other items of potential interest: selected peer,
Denys Vlasenkoae473352010-01-07 11:51:13 +0100994 * rootdelay, reftime, rootdisp, refid, ntp_status,
Denys Vlasenko12628b72010-01-11 01:31:59 +0100995 * last_update_offset, last_update_recv_time, discipline_jitter,
996 * how many peers have reachable_bits = 0?
Denys Vlasenkoede737b2010-01-06 12:27:47 +0100997 */
998
Denys Vlasenko6959f6b2010-01-07 08:31:46 +0100999 /* Don't want to wait: it may run hwclock --systohc, and that
1000 * may take some time (seconds): */
Denys Vlasenko8531d762010-03-18 22:44:00 +01001001 /*spawn_and_wait(argv);*/
Denys Vlasenko6959f6b2010-01-07 08:31:46 +01001002 spawn(argv);
Denys Vlasenkoede737b2010-01-06 12:27:47 +01001003
1004 unsetenv("stratum");
1005 unsetenv("freq_drift_ppm");
Denys Vlasenkoae473352010-01-07 11:51:13 +01001006 unsetenv("poll_interval");
Denys Vlasenko12628b72010-01-11 01:31:59 +01001007 unsetenv("offset");
Denys Vlasenkoede737b2010-01-06 12:27:47 +01001008 free(env1);
1009 free(env2);
Denys Vlasenkoae473352010-01-07 11:51:13 +01001010 free(env3);
Denys Vlasenko12628b72010-01-11 01:31:59 +01001011 free(env4);
Denys Vlasenkoede737b2010-01-06 12:27:47 +01001012}
1013
Denys Vlasenko0b002812010-01-03 08:59:59 +01001014static NOINLINE void
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001015step_time(double offset)
1016{
Denys Vlasenko0b002812010-01-03 08:59:59 +01001017 llist_t *item;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001018 double dtime;
Denys Vlasenkofc4ebd02012-02-28 02:45:00 +01001019 struct timeval tvc, tvn;
1020 char buf[sizeof("yyyy-mm-dd hh:mm:ss") + /*paranoia:*/ 4];
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001021 time_t tval;
1022
Denys Vlasenkofc4ebd02012-02-28 02:45:00 +01001023 gettimeofday(&tvc, NULL); /* never fails */
1024 dtime = tvc.tv_sec + (1.0e-6 * tvc.tv_usec) + offset;
1025 d_to_tv(dtime, &tvn);
1026 if (settimeofday(&tvn, NULL) == -1)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001027 bb_perror_msg_and_die("settimeofday");
1028
Denys Vlasenkofc4ebd02012-02-28 02:45:00 +01001029 VERB2 {
1030 tval = tvc.tv_sec;
Denys Vlasenko8f2cb7a2013-03-29 12:30:33 +01001031 strftime_YYYYMMDDHHMMSS(buf, sizeof(buf), &tval);
Denys Vlasenkofc4ebd02012-02-28 02:45:00 +01001032 bb_error_msg("current time is %s.%06u", buf, (unsigned)tvc.tv_usec);
1033 }
1034 tval = tvn.tv_sec;
Denys Vlasenko8f2cb7a2013-03-29 12:30:33 +01001035 strftime_YYYYMMDDHHMMSS(buf, sizeof(buf), &tval);
Denys Vlasenkofc4ebd02012-02-28 02:45:00 +01001036 bb_error_msg("setting time to %s.%06u (offset %+fs)", buf, (unsigned)tvn.tv_usec, offset);
Denys Vlasenko0b002812010-01-03 08:59:59 +01001037
1038 /* Correct various fields which contain time-relative values: */
1039
Denys Vlasenko4125a6b2012-06-11 11:41:46 +02001040 /* Globals: */
1041 G.cur_time += offset;
1042 G.last_update_recv_time += offset;
1043 G.last_script_run += offset;
1044
Denys Vlasenko0b002812010-01-03 08:59:59 +01001045 /* p->lastpkt_recv_time, p->next_action_time and such: */
1046 for (item = G.ntp_peers; item != NULL; item = item->link) {
1047 peer_t *pp = (peer_t *) item->data;
1048 reset_peer_stats(pp, offset);
Denys Vlasenko16c52a52012-02-23 14:28:47 +01001049 //bb_error_msg("offset:%+f pp->next_action_time:%f -> %f",
Denys Vlasenkoeff6d592010-06-24 20:23:40 +02001050 // offset, pp->next_action_time, pp->next_action_time + offset);
1051 pp->next_action_time += offset;
Denys Vlasenko4125a6b2012-06-11 11:41:46 +02001052 if (pp->p_fd >= 0) {
1053 /* We wait for reply from this peer too.
1054 * But due to step we are doing, reply's data is no longer
1055 * useful (in fact, it'll be bogus). Stop waiting for it.
1056 */
1057 close(pp->p_fd);
1058 pp->p_fd = -1;
1059 set_next(pp, RETRY_INTERVAL);
1060 }
Denys Vlasenko0b002812010-01-03 08:59:59 +01001061 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001062}
1063
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02001064static void clamp_pollexp_and_set_MAXSTRAT(void)
1065{
1066 if (G.poll_exp < MINPOLL)
1067 G.poll_exp = MINPOLL;
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001068 if (G.poll_exp > BIGPOLL)
1069 G.poll_exp = BIGPOLL;
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02001070 G.polladj_count = 0;
1071 G.stratum = MAXSTRAT;
1072}
1073
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001074
1075/*
1076 * Selection and clustering, and their helpers
1077 */
1078typedef struct {
1079 peer_t *p;
1080 int type;
1081 double edge;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001082 double opt_rd; /* optimization */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001083} point_t;
1084static int
1085compare_point_edge(const void *aa, const void *bb)
1086{
1087 const point_t *a = aa;
1088 const point_t *b = bb;
1089 if (a->edge < b->edge) {
1090 return -1;
1091 }
1092 return (a->edge > b->edge);
1093}
1094typedef struct {
1095 peer_t *p;
1096 double metric;
1097} survivor_t;
1098static int
1099compare_survivor_metric(const void *aa, const void *bb)
1100{
1101 const survivor_t *a = aa;
1102 const survivor_t *b = bb;
Denys Vlasenko510f56a2010-01-03 12:00:26 +01001103 if (a->metric < b->metric) {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001104 return -1;
Denys Vlasenko510f56a2010-01-03 12:00:26 +01001105 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001106 return (a->metric > b->metric);
1107}
1108static int
1109fit(peer_t *p, double rd)
1110{
Denys Vlasenko0b002812010-01-03 08:59:59 +01001111 if ((p->reachable_bits & (p->reachable_bits-1)) == 0) {
1112 /* One or zero bits in reachable_bits */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001113 VERB4 bb_error_msg("peer %s unfit for selection: unreachable", p->p_dotted);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001114 return 0;
1115 }
Denys Vlasenkofb132e42010-10-29 11:46:52 +02001116#if 0 /* we filter out such packets earlier */
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001117 if ((p->lastpkt_status & LI_ALARM) == LI_ALARM
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001118 || p->lastpkt_stratum >= MAXSTRAT
1119 ) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001120 VERB4 bb_error_msg("peer %s unfit for selection: bad status/stratum", p->p_dotted);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001121 return 0;
1122 }
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001123#endif
Denys Vlasenko0b002812010-01-03 08:59:59 +01001124 /* rd is root_distance(p) */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001125 if (rd > MAXDIST + FREQ_TOLERANCE * (1 << G.poll_exp)) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001126 VERB4 bb_error_msg("peer %s unfit for selection: root distance too high", p->p_dotted);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001127 return 0;
1128 }
1129//TODO
1130// /* Do we have a loop? */
1131// if (p->refid == p->dstaddr || p->refid == s.refid)
1132// return 0;
Denys Vlasenkob7c9fb22011-02-03 00:05:48 +01001133 return 1;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001134}
1135static peer_t*
Denys Vlasenko0b002812010-01-03 08:59:59 +01001136select_and_cluster(void)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001137{
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001138 peer_t *p;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001139 llist_t *item;
1140 int i, j;
1141 int size = 3 * G.peer_cnt;
1142 /* for selection algorithm */
1143 point_t point[size];
1144 unsigned num_points, num_candidates;
1145 double low, high;
1146 unsigned num_falsetickers;
1147 /* for cluster algorithm */
1148 survivor_t survivor[size];
1149 unsigned num_survivors;
1150
1151 /* Selection */
1152
1153 num_points = 0;
1154 item = G.ntp_peers;
Denys Vlasenkoff3f3ac2015-01-29 16:31:36 +01001155 while (item != NULL) {
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001156 double rd, offset;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001157
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001158 p = (peer_t *) item->data;
1159 rd = root_distance(p);
1160 offset = p->filter_offset;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001161 if (!fit(p, rd)) {
1162 item = item->link;
1163 continue;
1164 }
1165
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001166 VERB5 bb_error_msg("interval: [%f %f %f] %s",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001167 offset - rd,
1168 offset,
1169 offset + rd,
1170 p->p_dotted
1171 );
1172 point[num_points].p = p;
1173 point[num_points].type = -1;
1174 point[num_points].edge = offset - rd;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001175 point[num_points].opt_rd = rd;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001176 num_points++;
1177 point[num_points].p = p;
1178 point[num_points].type = 0;
1179 point[num_points].edge = offset;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001180 point[num_points].opt_rd = rd;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001181 num_points++;
1182 point[num_points].p = p;
1183 point[num_points].type = 1;
1184 point[num_points].edge = offset + rd;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001185 point[num_points].opt_rd = rd;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001186 num_points++;
1187 item = item->link;
1188 }
1189 num_candidates = num_points / 3;
1190 if (num_candidates == 0) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001191 VERB3 bb_error_msg("no valid datapoints%s", ", no peer selected");
Denys Vlasenko0b002812010-01-03 08:59:59 +01001192 return NULL;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001193 }
1194//TODO: sorting does not seem to be done in reference code
1195 qsort(point, num_points, sizeof(point[0]), compare_point_edge);
1196
1197 /* Start with the assumption that there are no falsetickers.
1198 * Attempt to find a nonempty intersection interval containing
1199 * the midpoints of all truechimers.
1200 * If a nonempty interval cannot be found, increase the number
1201 * of assumed falsetickers by one and try again.
1202 * If a nonempty interval is found and the number of falsetickers
1203 * is less than the number of truechimers, a majority has been found
1204 * and the midpoint of each truechimer represents
1205 * the candidates available to the cluster algorithm.
1206 */
1207 num_falsetickers = 0;
1208 while (1) {
1209 int c;
1210 unsigned num_midpoints = 0;
1211
1212 low = 1 << 9;
1213 high = - (1 << 9);
1214 c = 0;
1215 for (i = 0; i < num_points; i++) {
1216 /* We want to do:
1217 * if (point[i].type == -1) c++;
1218 * if (point[i].type == 1) c--;
1219 * and it's simpler to do it this way:
1220 */
1221 c -= point[i].type;
1222 if (c >= num_candidates - num_falsetickers) {
1223 /* If it was c++ and it got big enough... */
1224 low = point[i].edge;
1225 break;
1226 }
1227 if (point[i].type == 0)
1228 num_midpoints++;
1229 }
1230 c = 0;
1231 for (i = num_points-1; i >= 0; i--) {
1232 c += point[i].type;
1233 if (c >= num_candidates - num_falsetickers) {
1234 high = point[i].edge;
1235 break;
1236 }
1237 if (point[i].type == 0)
1238 num_midpoints++;
1239 }
1240 /* If the number of midpoints is greater than the number
1241 * of allowed falsetickers, the intersection contains at
1242 * least one truechimer with no midpoint - bad.
1243 * Also, interval should be nonempty.
1244 */
1245 if (num_midpoints <= num_falsetickers && low < high)
1246 break;
1247 num_falsetickers++;
1248 if (num_falsetickers * 2 >= num_candidates) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001249 VERB3 bb_error_msg("falsetickers:%d, candidates:%d%s",
1250 num_falsetickers, num_candidates,
1251 ", no peer selected");
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001252 return NULL;
1253 }
1254 }
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001255 VERB4 bb_error_msg("selected interval: [%f, %f]; candidates:%d falsetickers:%d",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001256 low, high, num_candidates, num_falsetickers);
1257
1258 /* Clustering */
1259
1260 /* Construct a list of survivors (p, metric)
1261 * from the chime list, where metric is dominated
1262 * first by stratum and then by root distance.
1263 * All other things being equal, this is the order of preference.
1264 */
1265 num_survivors = 0;
1266 for (i = 0; i < num_points; i++) {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001267 if (point[i].edge < low || point[i].edge > high)
1268 continue;
1269 p = point[i].p;
1270 survivor[num_survivors].p = p;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001271 /* x.opt_rd == root_distance(p); */
1272 survivor[num_survivors].metric = MAXDIST * p->lastpkt_stratum + point[i].opt_rd;
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001273 VERB5 bb_error_msg("survivor[%d] metric:%f peer:%s",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001274 num_survivors, survivor[num_survivors].metric, p->p_dotted);
1275 num_survivors++;
1276 }
1277 /* There must be at least MIN_SELECTED survivors to satisfy the
1278 * correctness assertions. Ordinarily, the Byzantine criteria
1279 * require four survivors, but for the demonstration here, one
1280 * is acceptable.
1281 */
1282 if (num_survivors < MIN_SELECTED) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001283 VERB3 bb_error_msg("survivors:%d%s",
1284 num_survivors,
1285 ", no peer selected");
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001286 return NULL;
1287 }
1288
1289//looks like this is ONLY used by the fact that later we pick survivor[0].
1290//we can avoid sorting then, just find the minimum once!
1291 qsort(survivor, num_survivors, sizeof(survivor[0]), compare_survivor_metric);
1292
1293 /* For each association p in turn, calculate the selection
1294 * jitter p->sjitter as the square root of the sum of squares
1295 * (p->offset - q->offset) over all q associations. The idea is
1296 * to repeatedly discard the survivor with maximum selection
1297 * jitter until a termination condition is met.
1298 */
1299 while (1) {
1300 unsigned max_idx = max_idx;
1301 double max_selection_jitter = max_selection_jitter;
1302 double min_jitter = min_jitter;
1303
1304 if (num_survivors <= MIN_CLUSTERED) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001305 VERB4 bb_error_msg("num_survivors %d <= %d, not discarding more",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001306 num_survivors, MIN_CLUSTERED);
1307 break;
1308 }
1309
1310 /* To make sure a few survivors are left
1311 * for the clustering algorithm to chew on,
1312 * we stop if the number of survivors
1313 * is less than or equal to MIN_CLUSTERED (3).
1314 */
1315 for (i = 0; i < num_survivors; i++) {
1316 double selection_jitter_sq;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001317
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001318 p = survivor[i].p;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001319 if (i == 0 || p->filter_jitter < min_jitter)
1320 min_jitter = p->filter_jitter;
1321
1322 selection_jitter_sq = 0;
1323 for (j = 0; j < num_survivors; j++) {
1324 peer_t *q = survivor[j].p;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001325 selection_jitter_sq += SQUARE(p->filter_offset - q->filter_offset);
1326 }
1327 if (i == 0 || selection_jitter_sq > max_selection_jitter) {
1328 max_selection_jitter = selection_jitter_sq;
1329 max_idx = i;
1330 }
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001331 VERB6 bb_error_msg("survivor %d selection_jitter^2:%f",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001332 i, selection_jitter_sq);
1333 }
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001334 max_selection_jitter = SQRT(max_selection_jitter / num_survivors);
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001335 VERB5 bb_error_msg("max_selection_jitter (at %d):%f min_jitter:%f",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001336 max_idx, max_selection_jitter, min_jitter);
1337
1338 /* If the maximum selection jitter is less than the
1339 * minimum peer jitter, then tossing out more survivors
1340 * will not lower the minimum peer jitter, so we might
1341 * as well stop.
1342 */
1343 if (max_selection_jitter < min_jitter) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001344 VERB4 bb_error_msg("max_selection_jitter:%f < min_jitter:%f, num_survivors:%d, not discarding more",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001345 max_selection_jitter, min_jitter, num_survivors);
1346 break;
1347 }
1348
1349 /* Delete survivor[max_idx] from the list
1350 * and go around again.
1351 */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001352 VERB6 bb_error_msg("dropping survivor %d", max_idx);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001353 num_survivors--;
1354 while (max_idx < num_survivors) {
1355 survivor[max_idx] = survivor[max_idx + 1];
1356 max_idx++;
1357 }
1358 }
1359
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001360 if (0) {
1361 /* Combine the offsets of the clustering algorithm survivors
1362 * using a weighted average with weight determined by the root
1363 * distance. Compute the selection jitter as the weighted RMS
1364 * difference between the first survivor and the remaining
1365 * survivors. In some cases the inherent clock jitter can be
1366 * reduced by not using this algorithm, especially when frequent
1367 * clockhopping is involved. bbox: thus we don't do it.
1368 */
1369 double x, y, z, w;
1370 y = z = w = 0;
1371 for (i = 0; i < num_survivors; i++) {
1372 p = survivor[i].p;
1373 x = root_distance(p);
1374 y += 1 / x;
1375 z += p->filter_offset / x;
1376 w += SQUARE(p->filter_offset - survivor[0].p->filter_offset) / x;
1377 }
1378 //G.cluster_offset = z / y;
1379 //G.cluster_jitter = SQRT(w / y);
1380 }
1381
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001382 /* Pick the best clock. If the old system peer is on the list
1383 * and at the same stratum as the first survivor on the list,
1384 * then don't do a clock hop. Otherwise, select the first
1385 * survivor on the list as the new system peer.
1386 */
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001387 p = survivor[0].p;
1388 if (G.last_update_peer
1389 && G.last_update_peer->lastpkt_stratum <= p->lastpkt_stratum
1390 ) {
1391 /* Starting from 1 is ok here */
1392 for (i = 1; i < num_survivors; i++) {
1393 if (G.last_update_peer == survivor[i].p) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001394 VERB5 bb_error_msg("keeping old synced peer");
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001395 p = G.last_update_peer;
1396 goto keep_old;
1397 }
1398 }
1399 }
1400 G.last_update_peer = p;
1401 keep_old:
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001402 VERB4 bb_error_msg("selected peer %s filter_offset:%+f age:%f",
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001403 p->p_dotted,
1404 p->filter_offset,
1405 G.cur_time - p->lastpkt_recv_time
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001406 );
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001407 return p;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001408}
1409
1410
1411/*
1412 * Local clock discipline and its helpers
1413 */
1414static void
1415set_new_values(int disc_state, double offset, double recv_time)
1416{
1417 /* Enter new state and set state variables. Note we use the time
1418 * of the last clock filter sample, which must be earlier than
1419 * the current time.
1420 */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001421 VERB4 bb_error_msg("disc_state=%d last update offset=%f recv_time=%f",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001422 disc_state, offset, recv_time);
1423 G.discipline_state = disc_state;
1424 G.last_update_offset = offset;
1425 G.last_update_recv_time = recv_time;
1426}
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001427/* Return: -1: decrease poll interval, 0: leave as is, 1: increase */
Denys Vlasenko0b002812010-01-03 08:59:59 +01001428static NOINLINE int
1429update_local_clock(peer_t *p)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001430{
1431 int rc;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001432 struct timex tmx;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001433 /* Note: can use G.cluster_offset instead: */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001434 double offset = p->filter_offset;
1435 double recv_time = p->lastpkt_recv_time;
1436 double abs_offset;
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001437#if !USING_KERNEL_PLL_LOOP
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001438 double freq_drift;
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001439#endif
Bartosz Golaszewski76ad7482014-01-18 15:36:27 +01001440#if !USING_KERNEL_PLL_LOOP || USING_INITIAL_FREQ_ESTIMATION
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001441 double since_last_update;
Bartosz Golaszewski76ad7482014-01-18 15:36:27 +01001442#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001443 double etemp, dtemp;
1444
1445 abs_offset = fabs(offset);
1446
Denys Vlasenko12628b72010-01-11 01:31:59 +01001447#if 0
Denys Vlasenko24928ff2010-01-25 19:30:16 +01001448 /* If needed, -S script can do it by looking at $offset
1449 * env var and killing parent */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001450 /* If the offset is too large, give up and go home */
1451 if (abs_offset > PANIC_THRESHOLD) {
1452 bb_error_msg_and_die("offset %f far too big, exiting", offset);
1453 }
Denys Vlasenko12628b72010-01-11 01:31:59 +01001454#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001455
1456 /* If this is an old update, for instance as the result
1457 * of a system peer change, avoid it. We never use
1458 * an old sample or the same sample twice.
1459 */
1460 if (recv_time <= G.last_update_recv_time) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001461 VERB3 bb_error_msg("update from %s: same or older datapoint, not using it",
1462 p->p_dotted);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001463 return 0; /* "leave poll interval as is" */
1464 }
1465
1466 /* Clock state machine transition function. This is where the
1467 * action is and defines how the system reacts to large time
1468 * and frequency errors.
1469 */
Bartosz Golaszewski76ad7482014-01-18 15:36:27 +01001470#if !USING_KERNEL_PLL_LOOP || USING_INITIAL_FREQ_ESTIMATION
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001471 since_last_update = recv_time - G.reftime;
Bartosz Golaszewski76ad7482014-01-18 15:36:27 +01001472#endif
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001473#if !USING_KERNEL_PLL_LOOP
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001474 freq_drift = 0;
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001475#endif
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001476#if USING_INITIAL_FREQ_ESTIMATION
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001477 if (G.discipline_state == STATE_FREQ) {
1478 /* Ignore updates until the stepout threshold */
1479 if (since_last_update < WATCH_THRESHOLD) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001480 VERB4 bb_error_msg("measuring drift, datapoint ignored, %f sec remains",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001481 WATCH_THRESHOLD - since_last_update);
1482 return 0; /* "leave poll interval as is" */
1483 }
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001484# if !USING_KERNEL_PLL_LOOP
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001485 freq_drift = (offset - G.last_update_offset) / since_last_update;
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001486# endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001487 }
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001488#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001489
1490 /* There are two main regimes: when the
1491 * offset exceeds the step threshold and when it does not.
1492 */
1493 if (abs_offset > STEP_THRESHOLD) {
Denys Vlasenko6c46eed2013-12-04 17:12:11 +01001494#if 0
Denys Vlasenkocb1dc1d2013-12-04 13:19:04 +01001495 double remains;
1496
Denys Vlasenko6c46eed2013-12-04 17:12:11 +01001497// This "spike state" seems to be useless, peer selection already drops
1498// occassional "bad" datapoints. If we are here, there were _many_
1499// large offsets. When a few first large offsets are seen,
1500// we end up in "no valid datapoints, no peer selected" state.
1501// Only when enough of them are seen (which means it's not a fluke),
1502// we end up here. Looks like _our_ clock is off.
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001503 switch (G.discipline_state) {
1504 case STATE_SYNC:
1505 /* The first outlyer: ignore it, switch to SPIK state */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001506 VERB3 bb_error_msg("update from %s: offset:%+f, spike%s",
1507 p->p_dotted, offset,
1508 "");
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001509 G.discipline_state = STATE_SPIK;
1510 return -1; /* "decrease poll interval" */
1511
1512 case STATE_SPIK:
1513 /* Ignore succeeding outlyers until either an inlyer
1514 * is found or the stepout threshold is exceeded.
1515 */
Denys Vlasenkocb1dc1d2013-12-04 13:19:04 +01001516 remains = WATCH_THRESHOLD - since_last_update;
1517 if (remains > 0) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001518 VERB3 bb_error_msg("update from %s: offset:%+f, spike%s",
1519 p->p_dotted, offset,
1520 ", datapoint ignored");
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001521 return -1; /* "decrease poll interval" */
1522 }
1523 /* fall through: we need to step */
1524 } /* switch */
Denys Vlasenko6c46eed2013-12-04 17:12:11 +01001525#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001526
1527 /* Step the time and clamp down the poll interval.
1528 *
1529 * In NSET state an initial frequency correction is
1530 * not available, usually because the frequency file has
1531 * not yet been written. Since the time is outside the
1532 * capture range, the clock is stepped. The frequency
1533 * will be set directly following the stepout interval.
1534 *
1535 * In FSET state the initial frequency has been set
1536 * from the frequency file. Since the time is outside
1537 * the capture range, the clock is stepped immediately,
1538 * rather than after the stepout interval. Guys get
1539 * nervous if it takes 17 minutes to set the clock for
1540 * the first time.
1541 *
1542 * In SPIK state the stepout threshold has expired and
1543 * the phase is still above the step threshold. Note
1544 * that a single spike greater than the step threshold
1545 * is always suppressed, even at the longer poll
1546 * intervals.
1547 */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001548 VERB4 bb_error_msg("stepping time by %+f; poll_exp=MINPOLL", offset);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001549 step_time(offset);
1550 if (option_mask32 & OPT_q) {
1551 /* We were only asked to set time once. Done. */
1552 exit(0);
1553 }
1554
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02001555 clamp_pollexp_and_set_MAXSTRAT();
Denys Vlasenkoede737b2010-01-06 12:27:47 +01001556
Denys Vlasenko12628b72010-01-11 01:31:59 +01001557 run_script("step", offset);
Denys Vlasenkoede737b2010-01-06 12:27:47 +01001558
Denys Vlasenkocb761132014-01-08 17:17:52 +01001559 recv_time += offset;
1560
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001561#if USING_INITIAL_FREQ_ESTIMATION
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001562 if (G.discipline_state == STATE_NSET) {
1563 set_new_values(STATE_FREQ, /*offset:*/ 0, recv_time);
1564 return 1; /* "ok to increase poll interval" */
1565 }
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001566#endif
Denys Vlasenko547ee792012-03-05 10:18:00 +01001567 abs_offset = offset = 0;
Denys Vlasenko132b0442012-03-05 00:51:48 +01001568 set_new_values(STATE_SYNC, offset, recv_time);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001569 } else { /* abs_offset <= STEP_THRESHOLD */
1570
Miroslav Lichvar760d0352014-10-05 03:10:15 +02001571 /* The ratio is calculated before jitter is updated to make
1572 * poll adjust code more sensitive to large offsets.
1573 */
1574 G.offset_to_jitter_ratio = abs_offset / G.discipline_jitter;
1575
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001576 /* Compute the clock jitter as the RMS of exponentially
1577 * weighted offset differences. Used by the poll adjust code.
1578 */
1579 etemp = SQUARE(G.discipline_jitter);
Denys Vlasenko74584b82012-03-02 01:22:40 +01001580 dtemp = SQUARE(offset - G.last_update_offset);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001581 G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG);
Miroslav Lichvar760d0352014-10-05 03:10:15 +02001582 if (G.discipline_jitter < G_precision_sec)
1583 G.discipline_jitter = G_precision_sec;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001584
1585 switch (G.discipline_state) {
1586 case STATE_NSET:
1587 if (option_mask32 & OPT_q) {
1588 /* We were only asked to set time once.
1589 * The clock is precise enough, no need to step.
1590 */
1591 exit(0);
1592 }
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001593#if USING_INITIAL_FREQ_ESTIMATION
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001594 /* This is the first update received and the frequency
1595 * has not been initialized. The first thing to do
1596 * is directly measure the oscillator frequency.
1597 */
1598 set_new_values(STATE_FREQ, offset, recv_time);
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001599#else
1600 set_new_values(STATE_SYNC, offset, recv_time);
1601#endif
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001602 VERB4 bb_error_msg("transitioning to FREQ, datapoint ignored");
Denys Vlasenko0b002812010-01-03 08:59:59 +01001603 return 0; /* "leave poll interval as is" */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001604
1605#if 0 /* this is dead code for now */
1606 case STATE_FSET:
1607 /* This is the first update and the frequency
1608 * has been initialized. Adjust the phase, but
1609 * don't adjust the frequency until the next update.
1610 */
1611 set_new_values(STATE_SYNC, offset, recv_time);
1612 /* freq_drift remains 0 */
1613 break;
1614#endif
1615
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001616#if USING_INITIAL_FREQ_ESTIMATION
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001617 case STATE_FREQ:
1618 /* since_last_update >= WATCH_THRESHOLD, we waited enough.
1619 * Correct the phase and frequency and switch to SYNC state.
1620 * freq_drift was already estimated (see code above)
1621 */
1622 set_new_values(STATE_SYNC, offset, recv_time);
1623 break;
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001624#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001625
1626 default:
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001627#if !USING_KERNEL_PLL_LOOP
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001628 /* Compute freq_drift due to PLL and FLL contributions.
1629 *
1630 * The FLL and PLL frequency gain constants
1631 * depend on the poll interval and Allan
1632 * intercept. The FLL is not used below one-half
1633 * the Allan intercept. Above that the loop gain
1634 * increases in steps to 1 / AVG.
1635 */
1636 if ((1 << G.poll_exp) > ALLAN / 2) {
1637 etemp = FLL - G.poll_exp;
1638 if (etemp < AVG)
1639 etemp = AVG;
1640 freq_drift += (offset - G.last_update_offset) / (MAXD(since_last_update, ALLAN) * etemp);
1641 }
1642 /* For the PLL the integration interval
1643 * (numerator) is the minimum of the update
1644 * interval and poll interval. This allows
1645 * oversampling, but not undersampling.
1646 */
1647 etemp = MIND(since_last_update, (1 << G.poll_exp));
1648 dtemp = (4 * PLL) << G.poll_exp;
1649 freq_drift += offset * etemp / SQUARE(dtemp);
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001650#endif
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001651 set_new_values(STATE_SYNC, offset, recv_time);
1652 break;
1653 }
Denys Vlasenkoede737b2010-01-06 12:27:47 +01001654 if (G.stratum != p->lastpkt_stratum + 1) {
1655 G.stratum = p->lastpkt_stratum + 1;
Denys Vlasenko12628b72010-01-11 01:31:59 +01001656 run_script("stratum", offset);
Denys Vlasenkoede737b2010-01-06 12:27:47 +01001657 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001658 }
1659
Denys Vlasenko0b002812010-01-03 08:59:59 +01001660 G.reftime = G.cur_time;
Denys Vlasenko1ee5afd2010-01-02 15:57:07 +01001661 G.ntp_status = p->lastpkt_status;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001662 G.refid = p->lastpkt_refid;
1663 G.rootdelay = p->lastpkt_rootdelay + p->lastpkt_delay;
Denys Vlasenko9b20adc2010-01-17 02:51:33 +01001664 dtemp = p->filter_jitter; // SQRT(SQUARE(p->filter_jitter) + SQUARE(G.cluster_jitter));
Denys Vlasenko0b002812010-01-03 08:59:59 +01001665 dtemp += MAXD(p->filter_dispersion + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time) + abs_offset, MINDISP);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001666 G.rootdisp = p->lastpkt_rootdisp + dtemp;
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001667 VERB4 bb_error_msg("updating leap/refid/reftime/rootdisp from peer %s", p->p_dotted);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001668
1669 /* We are in STATE_SYNC now, but did not do adjtimex yet.
1670 * (Any other state does not reach this, they all return earlier)
Denys Vlasenko132b0442012-03-05 00:51:48 +01001671 * By this time, freq_drift and offset are set
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001672 * to values suitable for adjtimex.
Denys Vlasenko61313112010-01-01 19:56:16 +01001673 */
1674#if !USING_KERNEL_PLL_LOOP
1675 /* Calculate the new frequency drift and frequency stability (wander).
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001676 * Compute the clock wander as the RMS of exponentially weighted
1677 * frequency differences. This is not used directly, but can,
1678 * along with the jitter, be a highly useful monitoring and
1679 * debugging tool.
1680 */
1681 dtemp = G.discipline_freq_drift + freq_drift;
Denys Vlasenko61313112010-01-01 19:56:16 +01001682 G.discipline_freq_drift = MAXD(MIND(MAXDRIFT, dtemp), -MAXDRIFT);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001683 etemp = SQUARE(G.discipline_wander);
1684 dtemp = SQUARE(dtemp);
1685 G.discipline_wander = SQRT(etemp + (dtemp - etemp) / AVG);
1686
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001687 VERB4 bb_error_msg("discipline freq_drift=%.9f(int:%ld corr:%e) wander=%f",
Denys Vlasenko61313112010-01-01 19:56:16 +01001688 G.discipline_freq_drift,
1689 (long)(G.discipline_freq_drift * 65536e6),
1690 freq_drift,
1691 G.discipline_wander);
1692#endif
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001693 VERB4 {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001694 memset(&tmx, 0, sizeof(tmx));
1695 if (adjtimex(&tmx) < 0)
1696 bb_perror_msg_and_die("adjtimex");
Denys Vlasenko8be49c32012-03-06 19:16:50 +01001697 bb_error_msg("p adjtimex freq:%ld offset:%+ld status:0x%x tc:%ld",
1698 tmx.freq, tmx.offset, tmx.status, tmx.constant);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001699 }
1700
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001701 memset(&tmx, 0, sizeof(tmx));
1702#if 0
Denys Vlasenko61313112010-01-01 19:56:16 +01001703//doesn't work, offset remains 0 (!) in kernel:
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001704//ntpd: set adjtimex freq:1786097 tmx.offset:77487
1705//ntpd: prev adjtimex freq:1786097 tmx.offset:0
1706//ntpd: cur adjtimex freq:1786097 tmx.offset:0
1707 tmx.modes = ADJ_FREQUENCY | ADJ_OFFSET;
1708 /* 65536 is one ppm */
1709 tmx.freq = G.discipline_freq_drift * 65536e6;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001710#endif
1711 tmx.modes = ADJ_OFFSET | ADJ_STATUS | ADJ_TIMECONST;// | ADJ_MAXERROR | ADJ_ESTERROR;
Denys Vlasenkofc47fce2016-02-10 06:55:07 +01001712 tmx.constant = (int)G.poll_exp - 4;
Denys Vlasenko132b0442012-03-05 00:51:48 +01001713 /* EXPERIMENTAL.
1714 * The below if statement should be unnecessary, but...
1715 * It looks like Linux kernel's PLL is far too gentle in changing
1716 * tmx.freq in response to clock offset. Offset keeps growing
1717 * and eventually we fall back to smaller poll intervals.
Denys Vlasenko10ad6222017-04-17 16:13:32 +02001718 * We can make correction more aggressive (about x2) by supplying
Denys Vlasenko132b0442012-03-05 00:51:48 +01001719 * PLL time constant which is one less than the real one.
1720 * To be on a safe side, let's do it only if offset is significantly
1721 * larger than jitter.
1722 */
Denys Vlasenkofc47fce2016-02-10 06:55:07 +01001723 if (G.offset_to_jitter_ratio >= TIMECONST_HACK_GATE)
Denys Vlasenko132b0442012-03-05 00:51:48 +01001724 tmx.constant--;
Denys Vlasenkofc47fce2016-02-10 06:55:07 +01001725 tmx.offset = (long)(offset * 1000000); /* usec */
1726 if (SLEW_THRESHOLD < STEP_THRESHOLD) {
1727 if (tmx.offset > (long)(SLEW_THRESHOLD * 1000000)) {
1728 tmx.offset = (long)(SLEW_THRESHOLD * 1000000);
1729 tmx.constant--;
1730 }
1731 if (tmx.offset < -(long)(SLEW_THRESHOLD * 1000000)) {
1732 tmx.offset = -(long)(SLEW_THRESHOLD * 1000000);
1733 tmx.constant--;
1734 }
1735 }
1736 if (tmx.constant < 0)
1737 tmx.constant = 0;
1738
1739 tmx.status = STA_PLL;
1740 if (G.ntp_status & LI_PLUSSEC)
1741 tmx.status |= STA_INS;
1742 if (G.ntp_status & LI_MINUSSEC)
1743 tmx.status |= STA_DEL;
Denys Vlasenko132b0442012-03-05 00:51:48 +01001744
1745 //tmx.esterror = (uint32_t)(clock_jitter * 1e6);
1746 //tmx.maxerror = (uint32_t)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001747 rc = adjtimex(&tmx);
1748 if (rc < 0)
1749 bb_perror_msg_and_die("adjtimex");
Denys Vlasenkod9109e32010-01-02 00:36:43 +01001750 /* NB: here kernel returns constant == G.poll_exp, not == G.poll_exp - 4.
1751 * Not sure why. Perhaps it is normal.
1752 */
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001753 VERB4 bb_error_msg("adjtimex:%d freq:%ld offset:%+ld status:0x%x",
Denys Vlasenko132b0442012-03-05 00:51:48 +01001754 rc, tmx.freq, tmx.offset, tmx.status);
Denys Vlasenko12628b72010-01-11 01:31:59 +01001755 G.kernel_freq_drift = tmx.freq / 65536;
Denys Vlasenko03718bb2016-02-24 01:22:45 +01001756 VERB2 bb_error_msg("update from:%s offset:%+f delay:%f jitter:%f clock drift:%+.3fppm tc:%d",
1757 p->p_dotted,
1758 offset,
1759 p->lastpkt_delay,
1760 G.discipline_jitter,
1761 (double)tmx.freq / 65536,
1762 (int)tmx.constant
1763 );
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001764
1765 return 1; /* "ok to increase poll interval" */
1766}
1767
1768
1769/*
1770 * We've got a new reply packet from a peer, process it
1771 * (helpers first)
1772 */
1773static unsigned
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02001774poll_interval(int upper_bound)
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001775{
Denys Vlasenko3e78f6f2014-02-09 15:35:04 +01001776 unsigned interval, r, mask;
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02001777 interval = 1 << G.poll_exp;
1778 if (interval > upper_bound)
1779 interval = upper_bound;
Denys Vlasenko3e78f6f2014-02-09 15:35:04 +01001780 mask = ((interval-1) >> 4) | 1;
Denys Vlasenko0ed5f7a2014-03-05 18:58:15 +01001781 r = rand();
Denys Vlasenko3e78f6f2014-02-09 15:35:04 +01001782 interval += r & mask; /* ~ random(0..1) * interval/16 */
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02001783 VERB4 bb_error_msg("chose poll interval:%u (poll_exp:%d)", interval, G.poll_exp);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001784 return interval;
1785}
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001786static void
Miroslav Lichvar590a22c2014-09-18 16:19:05 +02001787adjust_poll(int count)
1788{
1789 G.polladj_count += count;
1790 if (G.polladj_count > POLLADJ_LIMIT) {
1791 G.polladj_count = 0;
1792 if (G.poll_exp < MAXPOLL) {
1793 G.poll_exp++;
1794 VERB4 bb_error_msg("polladj: discipline_jitter:%f ++poll_exp=%d",
1795 G.discipline_jitter, G.poll_exp);
1796 }
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001797 } else if (G.polladj_count < -POLLADJ_LIMIT || (count < 0 && G.poll_exp > BIGPOLL)) {
Miroslav Lichvar590a22c2014-09-18 16:19:05 +02001798 G.polladj_count = 0;
1799 if (G.poll_exp > MINPOLL) {
1800 llist_t *item;
1801
1802 G.poll_exp--;
1803 /* Correct p->next_action_time in each peer
1804 * which waits for sending, so that they send earlier.
1805 * Old pp->next_action_time are on the order
1806 * of t + (1 << old_poll_exp) + small_random,
1807 * we simply need to subtract ~half of that.
1808 */
1809 for (item = G.ntp_peers; item != NULL; item = item->link) {
1810 peer_t *pp = (peer_t *) item->data;
1811 if (pp->p_fd < 0)
1812 pp->next_action_time -= (1 << G.poll_exp);
1813 }
1814 VERB4 bb_error_msg("polladj: discipline_jitter:%f --poll_exp=%d",
1815 G.discipline_jitter, G.poll_exp);
1816 }
1817 } else {
1818 VERB4 bb_error_msg("polladj: count:%d", G.polladj_count);
1819 }
1820}
1821static NOINLINE void
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001822recv_and_process_peer_pkt(peer_t *p)
1823{
1824 int rc;
1825 ssize_t size;
1826 msg_t msg;
1827 double T1, T2, T3, T4;
Denys Vlasenkod531f932014-04-19 19:00:16 +02001828 double offset;
1829 double prev_delay, delay;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001830 unsigned interval;
1831 datapoint_t *datapoint;
1832 peer_t *q;
1833
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +01001834 offset = 0;
1835
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001836 /* We can recvfrom here and check from.IP, but some multihomed
1837 * ntp servers reply from their *other IP*.
1838 * TODO: maybe we should check at least what we can: from.port == 123?
1839 */
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001840 recv_again:
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001841 size = recv(p->p_fd, &msg, sizeof(msg), MSG_DONTWAIT);
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001842 if (size < 0) {
1843 if (errno == EINTR)
1844 /* Signal caught */
1845 goto recv_again;
1846 if (errno == EAGAIN)
1847 /* There was no packet after all
1848 * (poll() returning POLLIN for a fd
1849 * is not a ironclad guarantee that data is there)
1850 */
1851 return;
1852 /*
1853 * If you need a different handling for a specific
1854 * errno, always explain it in comment.
1855 */
1856 bb_perror_msg_and_die("recv(%s) error", p->p_dotted);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001857 }
1858
1859 if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
1860 bb_error_msg("malformed packet received from %s", p->p_dotted);
Denys Vlasenko4125a6b2012-06-11 11:41:46 +02001861 return;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001862 }
1863
1864 if (msg.m_orgtime.int_partl != p->p_xmt_msg.m_xmttime.int_partl
1865 || msg.m_orgtime.fractionl != p->p_xmt_msg.m_xmttime.fractionl
1866 ) {
Denys Vlasenko4125a6b2012-06-11 11:41:46 +02001867 /* Somebody else's packet */
1868 return;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001869 }
1870
Denys Vlasenko4125a6b2012-06-11 11:41:46 +02001871 /* We do not expect any more packets from this peer for now.
1872 * Closing the socket informs kernel about it.
1873 * We open a new socket when we send a new query.
1874 */
1875 close(p->p_fd);
1876 p->p_fd = -1;
1877
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001878 if ((msg.m_status & LI_ALARM) == LI_ALARM
1879 || msg.m_stratum == 0
1880 || msg.m_stratum > NTP_MAXSTRATUM
1881 ) {
Denys Vlasenkod99ef632013-05-22 17:48:19 +02001882 bb_error_msg("reply from %s: peer is unsynced", p->p_dotted);
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001883 /*
1884 * Stratum 0 responses may have commands in 32-bit m_refid field:
1885 * "DENY", "RSTR" - peer does not like us at all,
1886 * "RATE" - peer is overloaded, reduce polling freq.
1887 * If poll interval is small, increase it.
1888 */
1889 if (G.poll_exp < BIGPOLL)
1890 goto increase_interval;
Denys Vlasenkod99ef632013-05-22 17:48:19 +02001891 goto pick_normal_interval;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001892 }
1893
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001894// /* Verify valid root distance */
1895// if (msg.m_rootdelay / 2 + msg.m_rootdisp >= MAXDISP || p->lastpkt_reftime > msg.m_xmt)
1896// return; /* invalid header values */
1897
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001898 /*
1899 * From RFC 2030 (with a correction to the delay math):
1900 *
1901 * Timestamp Name ID When Generated
1902 * ------------------------------------------------------------
1903 * Originate Timestamp T1 time request sent by client
1904 * Receive Timestamp T2 time request received by server
1905 * Transmit Timestamp T3 time reply sent by server
1906 * Destination Timestamp T4 time reply received by client
1907 *
1908 * The roundtrip delay and local clock offset are defined as
1909 *
1910 * delay = (T4 - T1) - (T3 - T2); offset = ((T2 - T1) + (T3 - T4)) / 2
1911 */
1912 T1 = p->p_xmttime;
1913 T2 = lfp_to_d(msg.m_rectime);
1914 T3 = lfp_to_d(msg.m_xmttime);
Denys Vlasenko0b002812010-01-03 08:59:59 +01001915 T4 = G.cur_time;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001916
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001917 /* The delay calculation is a special case. In cases where the
1918 * server and client clocks are running at different rates and
1919 * with very fast networks, the delay can appear negative. In
1920 * order to avoid violating the Principle of Least Astonishment,
1921 * the delay is clamped not less than the system precision.
1922 */
Denys Vlasenkod531f932014-04-19 19:00:16 +02001923 delay = (T4 - T1) - (T3 - T2);
1924 if (delay < G_precision_sec)
1925 delay = G_precision_sec;
Denys Vlasenkod99ef632013-05-22 17:48:19 +02001926 /*
1927 * If this packet's delay is much bigger than the last one,
1928 * it's better to just ignore it than use its much less precise value.
1929 */
Denys Vlasenkod531f932014-04-19 19:00:16 +02001930 prev_delay = p->p_raw_delay;
1931 p->p_raw_delay = delay;
1932 if (p->reachable_bits && delay > prev_delay * BAD_DELAY_GROWTH) {
Denys Vlasenko5a21c852014-04-20 13:04:23 +02001933 bb_error_msg("reply from %s: delay %f is too high, ignoring", p->p_dotted, delay);
Denys Vlasenkod99ef632013-05-22 17:48:19 +02001934 goto pick_normal_interval;
1935 }
1936
Denys Vlasenkod531f932014-04-19 19:00:16 +02001937 p->lastpkt_delay = delay;
1938 p->lastpkt_recv_time = T4;
1939 VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
1940 p->lastpkt_status = msg.m_status;
1941 p->lastpkt_stratum = msg.m_stratum;
1942 p->lastpkt_rootdelay = sfp_to_d(msg.m_rootdelay);
1943 p->lastpkt_rootdisp = sfp_to_d(msg.m_rootdisp);
1944 p->lastpkt_refid = msg.m_refid;
1945
Denys Vlasenkod99ef632013-05-22 17:48:19 +02001946 p->datapoint_idx = p->reachable_bits ? (p->datapoint_idx + 1) % NUM_DATAPOINTS : 0;
1947 datapoint = &p->filter_datapoint[p->datapoint_idx];
1948 datapoint->d_recv_time = T4;
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +01001949 datapoint->d_offset = offset = ((T2 - T1) + (T3 - T4)) / 2;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001950 datapoint->d_dispersion = LOG2D(msg.m_precision_exp) + G_precision_sec;
Denys Vlasenko0b002812010-01-03 08:59:59 +01001951 if (!p->reachable_bits) {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001952 /* 1st datapoint ever - replicate offset in every element */
1953 int i;
Denys Vlasenko132b0442012-03-05 00:51:48 +01001954 for (i = 0; i < NUM_DATAPOINTS; i++) {
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +01001955 p->filter_datapoint[i].d_offset = offset;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001956 }
1957 }
1958
Denys Vlasenko0b002812010-01-03 08:59:59 +01001959 p->reachable_bits |= 1;
Denys Vlasenko074e8dc2010-01-04 23:58:13 +01001960 if ((MAX_VERBOSE && G.verbose) || (option_mask32 & OPT_w)) {
Denys Vlasenko79bec062012-03-08 13:02:52 +01001961 bb_error_msg("reply from %s: offset:%+f delay:%f status:0x%02x strat:%d refid:0x%08x rootdelay:%f reach:0x%02x",
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001962 p->p_dotted,
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +01001963 offset,
Denys Vlasenko4168fdd2010-01-04 00:19:13 +01001964 p->lastpkt_delay,
1965 p->lastpkt_status,
1966 p->lastpkt_stratum,
1967 p->lastpkt_refid,
Denys Vlasenkod98dc922012-03-08 03:27:49 +01001968 p->lastpkt_rootdelay,
1969 p->reachable_bits
Denys Vlasenko4168fdd2010-01-04 00:19:13 +01001970 /* not shown: m_ppoll, m_precision_exp, m_rootdisp,
1971 * m_reftime, m_orgtime, m_rectime, m_xmttime
1972 */
1973 );
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01001974 }
1975
1976 /* Muck with statictics and update the clock */
Denys Vlasenko0b002812010-01-03 08:59:59 +01001977 filter_datapoints(p);
1978 q = select_and_cluster();
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001979 rc = 0;
Denys Vlasenko4168fdd2010-01-04 00:19:13 +01001980 if (q) {
Denys Vlasenko12628b72010-01-11 01:31:59 +01001981 if (!(option_mask32 & OPT_w)) {
Denys Vlasenko4168fdd2010-01-04 00:19:13 +01001982 rc = update_local_clock(q);
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02001983#if 0
1984//Disabled this because there is a case where largish offsets
1985//are unavoidable: if network round-trip delay is, say, ~0.6s,
1986//error in offset estimation would be ~delay/2 ~= 0.3s.
1987//Thus, offsets will be usually in -0.3...0.3s range.
1988//In this case, this code would keep poll interval small,
1989//but it won't be helping.
1990//BIGOFF check below deals with a case of seeing multi-second offsets.
1991
Denys Vlasenko12628b72010-01-11 01:31:59 +01001992 /* If drift is dangerously large, immediately
1993 * drop poll interval one step down.
1994 */
Denys Vlasenko5b9a9102010-01-17 01:05:58 +01001995 if (fabs(q->filter_offset) >= POLLDOWN_OFFSET) {
Denys Vlasenkoa14958c2013-12-04 16:32:09 +01001996 VERB4 bb_error_msg("offset:%+f > POLLDOWN_OFFSET", q->filter_offset);
Miroslav Lichvar590a22c2014-09-18 16:19:05 +02001997 adjust_poll(-POLLADJ_LIMIT * 3);
1998 rc = 0;
Denys Vlasenko12628b72010-01-11 01:31:59 +01001999 }
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02002000#endif
Denys Vlasenko12628b72010-01-11 01:31:59 +01002001 }
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02002002 } else {
2003 /* No peer selected.
2004 * If poll interval is small, increase it.
2005 */
2006 if (G.poll_exp < BIGPOLL)
2007 goto increase_interval;
Denys Vlasenko4168fdd2010-01-04 00:19:13 +01002008 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002009
2010 if (rc != 0) {
2011 /* Adjust the poll interval by comparing the current offset
2012 * with the clock jitter. If the offset is less than
2013 * the clock jitter times a constant, then the averaging interval
2014 * is increased, otherwise it is decreased. A bit of hysteresis
2015 * helps calm the dance. Works best using burst mode.
2016 */
Denys Vlasenko547ee792012-03-05 10:18:00 +01002017 if (rc > 0 && G.offset_to_jitter_ratio <= POLLADJ_GATE) {
Denys Vlasenkobfc2a322010-01-01 18:12:06 +01002018 /* was += G.poll_exp but it is a bit
2019 * too optimistic for my taste at high poll_exp's */
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02002020 increase_interval:
Miroslav Lichvar590a22c2014-09-18 16:19:05 +02002021 adjust_poll(MINPOLL);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002022 } else {
Denys Vlasenkofc47fce2016-02-10 06:55:07 +01002023 VERB3 if (rc > 0)
Denys Vlasenko4c48a642016-03-03 22:01:23 +01002024 bb_error_msg("want smaller interval: offset/jitter = %u",
2025 G.offset_to_jitter_ratio);
Miroslav Lichvar590a22c2014-09-18 16:19:05 +02002026 adjust_poll(-G.poll_exp * 2);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002027 }
2028 }
2029
2030 /* Decide when to send new query for this peer */
Denys Vlasenkod99ef632013-05-22 17:48:19 +02002031 pick_normal_interval:
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02002032 interval = poll_interval(INT_MAX);
2033 if (fabs(offset) >= BIGOFF && interval > BIGOFF_INTERVAL) {
Denys Vlasenkofc47fce2016-02-10 06:55:07 +01002034 /* If we are synced, offsets are less than SLEW_THRESHOLD,
Denys Vlasenko0b3a38b2013-12-08 16:11:04 +01002035 * or at the very least not much larger than it.
2036 * Now we see a largish one.
2037 * Either this peer is feeling bad, or packet got corrupted,
2038 * or _our_ clock is wrong now and _all_ peers will show similar
2039 * largish offsets too.
2040 * I observed this with laptop suspend stopping clock.
2041 * In any case, it makes sense to make next request soonish:
2042 * cases 1 and 2: get a better datapoint,
2043 * case 3: allows to resync faster.
2044 */
2045 interval = BIGOFF_INTERVAL;
2046 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002047
Denys Vlasenko4168fdd2010-01-04 00:19:13 +01002048 set_next(p, interval);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002049}
2050
2051#if ENABLE_FEATURE_NTPD_SERVER
Denys Vlasenko0b002812010-01-03 08:59:59 +01002052static NOINLINE void
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002053recv_and_process_client_pkt(void /*int fd*/)
2054{
2055 ssize_t size;
Cristian Ionescu-Idbohrn662972a2011-05-16 03:53:00 +02002056 //uint8_t version;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002057 len_and_sockaddr *to;
2058 struct sockaddr *from;
2059 msg_t msg;
2060 uint8_t query_status;
2061 l_fixedpt_t query_xmttime;
2062
Denys Vlasenko3e3a8d52012-04-01 16:31:04 +02002063 to = get_sock_lsa(G_listen_fd);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002064 from = xzalloc(to->len);
2065
Denys Vlasenko3e3a8d52012-04-01 16:31:04 +02002066 size = recv_from_to(G_listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002067 if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
2068 char *addr;
2069 if (size < 0) {
2070 if (errno == EAGAIN)
2071 goto bail;
2072 bb_perror_msg_and_die("recv");
2073 }
2074 addr = xmalloc_sockaddr2dotted_noport(from);
2075 bb_error_msg("malformed packet received from %s: size %u", addr, (int)size);
2076 free(addr);
2077 goto bail;
2078 }
2079
Miroslav Lichvar150dc7a2016-08-01 20:24:24 +02002080 /* Respond only to client and symmetric active packets */
2081 if ((msg.m_status & MODE_MASK) != MODE_CLIENT
2082 && (msg.m_status & MODE_MASK) != MODE_SYM_ACT
2083 ) {
2084 goto bail;
2085 }
2086
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002087 query_status = msg.m_status;
2088 query_xmttime = msg.m_xmttime;
2089
2090 /* Build a reply packet */
2091 memset(&msg, 0, sizeof(msg));
Paul Marksb7841cf2013-01-14 02:39:10 +01002092 msg.m_status = G.stratum < MAXSTRAT ? (G.ntp_status & LI_MASK) : LI_ALARM;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002093 msg.m_status |= (query_status & VERSION_MASK);
2094 msg.m_status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
Denys Vlasenko69675782013-01-14 01:34:48 +01002095 MODE_SERVER : MODE_SYM_PAS;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002096 msg.m_stratum = G.stratum;
2097 msg.m_ppoll = G.poll_exp;
2098 msg.m_precision_exp = G_precision_exp;
Denys Vlasenko0b002812010-01-03 08:59:59 +01002099 /* this time was obtained between poll() and recv() */
2100 msg.m_rectime = d_to_lfp(G.cur_time);
2101 msg.m_xmttime = d_to_lfp(gettime1900d()); /* this instant */
Denys Vlasenkod6782572010-10-04 01:20:44 +02002102 if (G.peer_cnt == 0) {
2103 /* we have no peers: "stratum 1 server" mode. reftime = our own time */
2104 G.reftime = G.cur_time;
2105 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002106 msg.m_reftime = d_to_lfp(G.reftime);
2107 msg.m_orgtime = query_xmttime;
2108 msg.m_rootdelay = d_to_sfp(G.rootdelay);
2109//simple code does not do this, fix simple code!
2110 msg.m_rootdisp = d_to_sfp(G.rootdisp);
Cristian Ionescu-Idbohrn662972a2011-05-16 03:53:00 +02002111 //version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002112 msg.m_refid = G.refid; // (version > (3 << VERSION_SHIFT)) ? G.refid : G.refid3;
2113
2114 /* We reply from the local address packet was sent to,
2115 * this makes to/from look swapped here: */
Denys Vlasenko3e3a8d52012-04-01 16:31:04 +02002116 do_sendto(G_listen_fd,
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002117 /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
2118 &msg, size);
2119
2120 bail:
2121 free(to);
2122 free(from);
2123}
2124#endif
2125
2126/* Upstream ntpd's options:
2127 *
2128 * -4 Force DNS resolution of host names to the IPv4 namespace.
2129 * -6 Force DNS resolution of host names to the IPv6 namespace.
2130 * -a Require cryptographic authentication for broadcast client,
2131 * multicast client and symmetric passive associations.
2132 * This is the default.
2133 * -A Do not require cryptographic authentication for broadcast client,
2134 * multicast client and symmetric passive associations.
2135 * This is almost never a good idea.
2136 * -b Enable the client to synchronize to broadcast servers.
2137 * -c conffile
2138 * Specify the name and path of the configuration file,
2139 * default /etc/ntp.conf
2140 * -d Specify debugging mode. This option may occur more than once,
2141 * with each occurrence indicating greater detail of display.
2142 * -D level
2143 * Specify debugging level directly.
2144 * -f driftfile
2145 * Specify the name and path of the frequency file.
2146 * This is the same operation as the "driftfile FILE"
2147 * configuration command.
2148 * -g Normally, ntpd exits with a message to the system log
2149 * if the offset exceeds the panic threshold, which is 1000 s
2150 * by default. This option allows the time to be set to any value
2151 * without restriction; however, this can happen only once.
2152 * If the threshold is exceeded after that, ntpd will exit
2153 * with a message to the system log. This option can be used
2154 * with the -q and -x options. See the tinker command for other options.
2155 * -i jaildir
2156 * Chroot the server to the directory jaildir. This option also implies
2157 * that the server attempts to drop root privileges at startup
2158 * (otherwise, chroot gives very little additional security).
2159 * You may need to also specify a -u option.
2160 * -k keyfile
2161 * Specify the name and path of the symmetric key file,
2162 * default /etc/ntp/keys. This is the same operation
2163 * as the "keys FILE" configuration command.
2164 * -l logfile
2165 * Specify the name and path of the log file. The default
2166 * is the system log file. This is the same operation as
2167 * the "logfile FILE" configuration command.
2168 * -L Do not listen to virtual IPs. The default is to listen.
2169 * -n Don't fork.
2170 * -N To the extent permitted by the operating system,
2171 * run the ntpd at the highest priority.
2172 * -p pidfile
2173 * Specify the name and path of the file used to record the ntpd
2174 * process ID. This is the same operation as the "pidfile FILE"
2175 * configuration command.
2176 * -P priority
2177 * To the extent permitted by the operating system,
2178 * run the ntpd at the specified priority.
2179 * -q Exit the ntpd just after the first time the clock is set.
2180 * This behavior mimics that of the ntpdate program, which is
2181 * to be retired. The -g and -x options can be used with this option.
2182 * Note: The kernel time discipline is disabled with this option.
2183 * -r broadcastdelay
2184 * Specify the default propagation delay from the broadcast/multicast
2185 * server to this client. This is necessary only if the delay
2186 * cannot be computed automatically by the protocol.
2187 * -s statsdir
2188 * Specify the directory path for files created by the statistics
2189 * facility. This is the same operation as the "statsdir DIR"
2190 * configuration command.
2191 * -t key
2192 * Add a key number to the trusted key list. This option can occur
2193 * more than once.
2194 * -u user[:group]
2195 * Specify a user, and optionally a group, to switch to.
2196 * -v variable
2197 * -V variable
2198 * Add a system variable listed by default.
2199 * -x Normally, the time is slewed if the offset is less than the step
2200 * threshold, which is 128 ms by default, and stepped if above
2201 * the threshold. This option sets the threshold to 600 s, which is
2202 * well within the accuracy window to set the clock manually.
2203 * Note: since the slew rate of typical Unix kernels is limited
2204 * to 0.5 ms/s, each second of adjustment requires an amortization
2205 * interval of 2000 s. Thus, an adjustment as much as 600 s
2206 * will take almost 14 days to complete. This option can be used
2207 * with the -g and -q options. See the tinker command for other options.
2208 * Note: The kernel time discipline is disabled with this option.
2209 */
2210
2211/* By doing init in a separate function we decrease stack usage
2212 * in main loop.
2213 */
2214static NOINLINE void ntp_init(char **argv)
2215{
2216 unsigned opts;
2217 llist_t *peers;
2218
Denys Vlasenko0ed5f7a2014-03-05 18:58:15 +01002219 srand(getpid());
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002220
2221 if (getuid())
2222 bb_error_msg_and_die(bb_msg_you_must_be_root);
2223
2224 /* Set some globals */
Miroslav Lichvar760d0352014-10-05 03:10:15 +02002225 G.discipline_jitter = G_precision_sec;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002226 G.stratum = MAXSTRAT;
Denys Vlasenko0b002812010-01-03 08:59:59 +01002227 if (BURSTPOLL != 0)
2228 G.poll_exp = BURSTPOLL; /* speeds up initial sync */
Denys Vlasenkoede737b2010-01-06 12:27:47 +01002229 G.last_script_run = G.reftime = G.last_update_recv_time = gettime1900d(); /* sets G.cur_time too */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002230
2231 /* Parse options */
2232 peers = NULL;
Denys Vlasenko237bedd2016-07-06 21:58:02 +02002233 opt_complementary = "dd:wn" /* -d: counter; -p: list; -w implies -n */
Denys Vlasenko278842d2014-07-15 15:06:54 +02002234 IF_FEATURE_NTPD_SERVER(":Il"); /* -I implies -l */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002235 opts = getopt32(argv,
2236 "nqNx" /* compat */
Denys Vlasenko237bedd2016-07-06 21:58:02 +02002237 "wp:*S:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
Denys Vlasenko278842d2014-07-15 15:06:54 +02002238 IF_FEATURE_NTPD_SERVER("I:") /* compat */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002239 "d" /* compat */
2240 "46aAbgL", /* compat, ignored */
Natanael Copab62ea342017-01-06 16:18:45 +01002241 &peers, &G.script_name,
Denys Vlasenko278842d2014-07-15 15:06:54 +02002242#if ENABLE_FEATURE_NTPD_SERVER
2243 &G.if_name,
2244#endif
2245 &G.verbose);
Denys Vlasenko504fe452014-03-23 15:06:38 +01002246
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002247// if (opts & OPT_x) /* disable stepping, only slew is allowed */
2248// G.time_was_stepped = 1;
Denys Vlasenkoaabb0a92016-07-03 17:58:54 +02002249
2250#if ENABLE_FEATURE_NTPD_SERVER
2251 G_listen_fd = -1;
2252 if (opts & OPT_l) {
2253 G_listen_fd = create_and_bind_dgram_or_die(NULL, 123);
2254 if (G.if_name) {
2255 if (setsockopt_bindtodevice(G_listen_fd, G.if_name))
2256 xfunc_die();
2257 }
2258 socket_want_pktinfo(G_listen_fd);
2259 setsockopt_int(G_listen_fd, IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY);
2260 }
2261#endif
2262 /* I hesitate to set -20 prio. -15 should be high enough for timekeeping */
2263 if (opts & OPT_N)
2264 setpriority(PRIO_PROCESS, 0, -15);
2265
Denys Vlasenkoaabb0a92016-07-03 17:58:54 +02002266 if (!(opts & OPT_n)) {
2267 bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO, argv);
2268 logmode = LOGMODE_NONE;
2269 }
2270
Denys Vlasenkod6782572010-10-04 01:20:44 +02002271 if (peers) {
2272 while (peers)
2273 add_peers(llist_pop(&peers));
Denys Vlasenko504fe452014-03-23 15:06:38 +01002274 }
2275#if ENABLE_FEATURE_NTPD_CONF
2276 else {
2277 parser_t *parser;
2278 char *token[3];
2279
2280 parser = config_open("/etc/ntp.conf");
2281 while (config_read(parser, token, 3, 1, "# \t", PARSE_NORMAL)) {
2282 if (strcmp(token[0], "server") == 0 && token[1]) {
2283 add_peers(token[1]);
2284 continue;
2285 }
2286 bb_error_msg("skipping %s:%u: unimplemented command '%s'",
2287 "/etc/ntp.conf", parser->lineno, token[0]
2288 );
2289 }
2290 config_close(parser);
2291 }
2292#endif
2293 if (G.peer_cnt == 0) {
2294 if (!(opts & OPT_l))
2295 bb_show_usage();
Denys Vlasenkod6782572010-10-04 01:20:44 +02002296 /* -l but no peers: "stratum 1 server" mode */
2297 G.stratum = 1;
2298 }
Denys Vlasenko74c992a2010-08-27 02:15:01 +02002299 /* If network is up, syncronization occurs in ~10 seconds.
Denys Vlasenko8e23faf2011-04-07 01:45:20 +02002300 * We give "ntpd -q" 10 seconds to get first reply,
2301 * then another 50 seconds to finish syncing.
Denys Vlasenko74c992a2010-08-27 02:15:01 +02002302 *
2303 * I tested ntpd 4.2.6p1 and apparently it never exits
2304 * (will try forever), but it does not feel right.
2305 * The goal of -q is to act like ntpdate: set time
2306 * after a reasonably small period of polling, or fail.
2307 */
Denys Vlasenko8e23faf2011-04-07 01:45:20 +02002308 if (opts & OPT_q) {
2309 option_mask32 |= OPT_qq;
2310 alarm(10);
2311 }
Denys Vlasenko74c992a2010-08-27 02:15:01 +02002312
2313 bb_signals(0
2314 | (1 << SIGTERM)
2315 | (1 << SIGINT)
2316 | (1 << SIGALRM)
2317 , record_signo
2318 );
2319 bb_signals(0
2320 | (1 << SIGPIPE)
2321 | (1 << SIGCHLD)
2322 , SIG_IGN
2323 );
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002324}
2325
2326int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
2327int ntpd_main(int argc UNUSED_PARAM, char **argv)
2328{
Denys Vlasenko0b002812010-01-03 08:59:59 +01002329#undef G
2330 struct globals G;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002331 struct pollfd *pfd;
2332 peer_t **idx2peer;
Denys Vlasenko0b002812010-01-03 08:59:59 +01002333 unsigned cnt;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002334
Denys Vlasenko0b002812010-01-03 08:59:59 +01002335 memset(&G, 0, sizeof(G));
2336 SET_PTR_TO_GLOBALS(&G);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002337
2338 ntp_init(argv);
2339
Denys Vlasenko0b002812010-01-03 08:59:59 +01002340 /* If ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
2341 cnt = G.peer_cnt + ENABLE_FEATURE_NTPD_SERVER;
2342 idx2peer = xzalloc(sizeof(idx2peer[0]) * cnt);
2343 pfd = xzalloc(sizeof(pfd[0]) * cnt);
2344
Leonid Lisovskiy894ef602010-10-20 22:36:51 +02002345 /* Countdown: we never sync before we sent INITIAL_SAMPLES+1
Denys Vlasenko65d722b2010-01-11 02:14:04 +01002346 * packets to each peer.
Denys Vlasenko0b002812010-01-03 08:59:59 +01002347 * NB: if some peer is not responding, we may end up sending
2348 * fewer packets to it and more to other peers.
Leonid Lisovskiy894ef602010-10-20 22:36:51 +02002349 * NB2: sync usually happens using INITIAL_SAMPLES packets,
Denys Vlasenko65d722b2010-01-11 02:14:04 +01002350 * since last reply does not come back instantaneously.
Denys Vlasenko0b002812010-01-03 08:59:59 +01002351 */
Leonid Lisovskiy894ef602010-10-20 22:36:51 +02002352 cnt = G.peer_cnt * (INITIAL_SAMPLES + 1);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002353
Anthony G. Basile12677ac2012-12-10 14:49:39 -05002354 write_pidfile(CONFIG_PID_FILE_PATH "/ntpd.pid");
2355
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002356 while (!bb_got_signal) {
2357 llist_t *item;
2358 unsigned i, j;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002359 int nfds, timeout;
Denys Vlasenko0b002812010-01-03 08:59:59 +01002360 double nextaction;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002361
2362 /* Nothing between here and poll() blocks for any significant time */
2363
Denys Vlasenko0b002812010-01-03 08:59:59 +01002364 nextaction = G.cur_time + 3600;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002365
2366 i = 0;
2367#if ENABLE_FEATURE_NTPD_SERVER
Denys Vlasenko3e3a8d52012-04-01 16:31:04 +02002368 if (G_listen_fd != -1) {
2369 pfd[0].fd = G_listen_fd;
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002370 pfd[0].events = POLLIN;
2371 i++;
2372 }
2373#endif
2374 /* Pass over peer list, send requests, time out on receives */
Denys Vlasenko0b002812010-01-03 08:59:59 +01002375 for (item = G.ntp_peers; item != NULL; item = item->link) {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002376 peer_t *p = (peer_t *) item->data;
2377
Denys Vlasenko0b002812010-01-03 08:59:59 +01002378 if (p->next_action_time <= G.cur_time) {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002379 if (p->p_fd == -1) {
2380 /* Time to send new req */
Denys Vlasenko0b002812010-01-03 08:59:59 +01002381 if (--cnt == 0) {
Miroslav Lichvarfb143f72014-09-18 16:19:03 +02002382 VERB4 bb_error_msg("disabling burst mode");
2383 G.polladj_count = 0;
2384 G.poll_exp = MINPOLL;
Denys Vlasenko0b002812010-01-03 08:59:59 +01002385 }
2386 send_query_to_peer(p);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002387 } else {
2388 /* Timed out waiting for reply */
2389 close(p->p_fd);
2390 p->p_fd = -1;
Miroslav Lichvarb434ce72014-10-02 17:18:43 +02002391 /* If poll interval is small, increase it */
2392 if (G.poll_exp < BIGPOLL)
2393 adjust_poll(MINPOLL);
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02002394 timeout = poll_interval(NOREPLY_INTERVAL);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002395 bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
Denys Vlasenko0b002812010-01-03 08:59:59 +01002396 p->p_dotted, p->reachable_bits, timeout);
Denys Vlasenkoc8641962016-03-04 07:26:08 +01002397
2398 /* What if don't see it because it changed its IP? */
Denys Vlasenkoe4caf1d2016-06-06 02:26:49 +02002399 if (p->reachable_bits == 0)
Natanael Copab62ea342017-01-06 16:18:45 +01002400 resolve_peer_hostname(p);
Denys Vlasenkoc8641962016-03-04 07:26:08 +01002401
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002402 set_next(p, timeout);
2403 }
2404 }
2405
2406 if (p->next_action_time < nextaction)
2407 nextaction = p->next_action_time;
2408
2409 if (p->p_fd >= 0) {
2410 /* Wait for reply from this peer */
2411 pfd[i].fd = p->p_fd;
2412 pfd[i].events = POLLIN;
2413 idx2peer[i] = p;
2414 i++;
2415 }
2416 }
2417
Denys Vlasenko0b002812010-01-03 08:59:59 +01002418 timeout = nextaction - G.cur_time;
2419 if (timeout < 0)
2420 timeout = 0;
2421 timeout++; /* (nextaction - G.cur_time) rounds down, compensating */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002422
2423 /* Here we may block */
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +01002424 VERB2 {
Denys Vlasenko3e3a8d52012-04-01 16:31:04 +02002425 if (i > (ENABLE_FEATURE_NTPD_SERVER && G_listen_fd != -1)) {
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +01002426 /* We wait for at least one reply.
2427 * Poll for it, without wasting time for message.
2428 * Since replies often come under 1 second, this also
2429 * reduces clutter in logs.
2430 */
2431 nfds = poll(pfd, i, 1000);
2432 if (nfds != 0)
2433 goto did_poll;
2434 if (--timeout <= 0)
2435 goto did_poll;
2436 }
Denys Vlasenko8be49c32012-03-06 19:16:50 +01002437 bb_error_msg("poll:%us sockets:%u interval:%us", timeout, i, 1 << G.poll_exp);
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +01002438 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002439 nfds = poll(pfd, i, timeout * 1000);
Denys Vlasenkoe8ce2852012-03-03 12:15:46 +01002440 did_poll:
Denys Vlasenko0b002812010-01-03 08:59:59 +01002441 gettime1900d(); /* sets G.cur_time */
Denys Vlasenkoede737b2010-01-06 12:27:47 +01002442 if (nfds <= 0) {
Denys Vlasenko5ffdd1d2013-05-22 18:16:34 +02002443 if (!bb_got_signal /* poll wasn't interrupted by a signal */
2444 && G.cur_time - G.last_script_run > 11*60
2445 ) {
Denys Vlasenkoede737b2010-01-06 12:27:47 +01002446 /* Useful for updating battery-backed RTC and such */
Denys Vlasenko12628b72010-01-11 01:31:59 +01002447 run_script("periodic", G.last_update_offset);
Denys Vlasenko06667f22010-01-06 13:05:08 +01002448 gettime1900d(); /* sets G.cur_time */
Denys Vlasenkoede737b2010-01-06 12:27:47 +01002449 }
Denys Vlasenko5ffdd1d2013-05-22 18:16:34 +02002450 goto check_unsync;
Denys Vlasenkoede737b2010-01-06 12:27:47 +01002451 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002452
2453 /* Process any received packets */
2454 j = 0;
2455#if ENABLE_FEATURE_NTPD_SERVER
Denys Vlasenko0b002812010-01-03 08:59:59 +01002456 if (G.listen_fd != -1) {
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002457 if (pfd[0].revents /* & (POLLIN|POLLERR)*/) {
2458 nfds--;
Denys Vlasenko0b002812010-01-03 08:59:59 +01002459 recv_and_process_client_pkt(/*G.listen_fd*/);
2460 gettime1900d(); /* sets G.cur_time */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002461 }
2462 j = 1;
2463 }
2464#endif
2465 for (; nfds != 0 && j < i; j++) {
2466 if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
Denys Vlasenko8e23faf2011-04-07 01:45:20 +02002467 /*
2468 * At init, alarm was set to 10 sec.
2469 * Now we did get a reply.
2470 * Increase timeout to 50 seconds to finish syncing.
2471 */
2472 if (option_mask32 & OPT_qq) {
2473 option_mask32 &= ~OPT_qq;
2474 alarm(50);
2475 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002476 nfds--;
2477 recv_and_process_peer_pkt(idx2peer[j]);
Denys Vlasenko0b002812010-01-03 08:59:59 +01002478 gettime1900d(); /* sets G.cur_time */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002479 }
2480 }
Denys Vlasenkod99ef632013-05-22 17:48:19 +02002481
Denys Vlasenko5ffdd1d2013-05-22 18:16:34 +02002482 check_unsync:
Denys Vlasenkod99ef632013-05-22 17:48:19 +02002483 if (G.ntp_peers && G.stratum != MAXSTRAT) {
2484 for (item = G.ntp_peers; item != NULL; item = item->link) {
2485 peer_t *p = (peer_t *) item->data;
2486 if (p->reachable_bits)
2487 goto have_reachable_peer;
2488 }
2489 /* No peer responded for last 8 packets, panic */
Denys Vlasenkod3fe9602014-09-27 22:56:09 +02002490 clamp_pollexp_and_set_MAXSTRAT();
Denys Vlasenko5a7e3372013-05-23 16:06:59 +02002491 run_script("unsync", 0.0);
Denys Vlasenkod99ef632013-05-22 17:48:19 +02002492 have_reachable_peer: ;
2493 }
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002494 } /* while (!bb_got_signal) */
2495
Anthony G. Basile12677ac2012-12-10 14:49:39 -05002496 remove_pidfile(CONFIG_PID_FILE_PATH "/ntpd.pid");
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002497 kill_myself_with_sig(bb_got_signal);
2498}
2499
2500
2501
2502
2503
2504
2505/*** openntpd-4.6 uses only adjtime, not adjtimex ***/
2506
2507/*** ntp-4.2.6/ntpd/ntp_loopfilter.c - adjtimex usage ***/
2508
2509#if 0
2510static double
2511direct_freq(double fp_offset)
2512{
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002513#ifdef KERNEL_PLL
2514 /*
2515 * If the kernel is enabled, we need the residual offset to
2516 * calculate the frequency correction.
2517 */
2518 if (pll_control && kern_enable) {
2519 memset(&ntv, 0, sizeof(ntv));
2520 ntp_adjtime(&ntv);
2521#ifdef STA_NANO
2522 clock_offset = ntv.offset / 1e9;
2523#else /* STA_NANO */
2524 clock_offset = ntv.offset / 1e6;
2525#endif /* STA_NANO */
2526 drift_comp = FREQTOD(ntv.freq);
2527 }
2528#endif /* KERNEL_PLL */
2529 set_freq((fp_offset - clock_offset) / (current_time - clock_epoch) + drift_comp);
2530 wander_resid = 0;
2531 return drift_comp;
2532}
2533
2534static void
Denys Vlasenkofb132e42010-10-29 11:46:52 +02002535set_freq(double freq) /* frequency update */
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002536{
2537 char tbuf[80];
2538
2539 drift_comp = freq;
2540
2541#ifdef KERNEL_PLL
2542 /*
2543 * If the kernel is enabled, update the kernel frequency.
2544 */
2545 if (pll_control && kern_enable) {
2546 memset(&ntv, 0, sizeof(ntv));
2547 ntv.modes = MOD_FREQUENCY;
2548 ntv.freq = DTOFREQ(drift_comp);
2549 ntp_adjtime(&ntv);
2550 snprintf(tbuf, sizeof(tbuf), "kernel %.3f PPM", drift_comp * 1e6);
2551 report_event(EVNT_FSET, NULL, tbuf);
2552 } else {
2553 snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
2554 report_event(EVNT_FSET, NULL, tbuf);
2555 }
2556#else /* KERNEL_PLL */
2557 snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
2558 report_event(EVNT_FSET, NULL, tbuf);
2559#endif /* KERNEL_PLL */
2560}
2561
2562...
2563...
2564...
2565
2566#ifdef KERNEL_PLL
2567 /*
2568 * This code segment works when clock adjustments are made using
2569 * precision time kernel support and the ntp_adjtime() system
2570 * call. This support is available in Solaris 2.6 and later,
2571 * Digital Unix 4.0 and later, FreeBSD, Linux and specially
2572 * modified kernels for HP-UX 9 and Ultrix 4. In the case of the
2573 * DECstation 5000/240 and Alpha AXP, additional kernel
2574 * modifications provide a true microsecond clock and nanosecond
2575 * clock, respectively.
2576 *
2577 * Important note: The kernel discipline is used only if the
2578 * step threshold is less than 0.5 s, as anything higher can
2579 * lead to overflow problems. This might occur if some misguided
2580 * lad set the step threshold to something ridiculous.
2581 */
2582 if (pll_control && kern_enable) {
2583
2584#define MOD_BITS (MOD_OFFSET | MOD_MAXERROR | MOD_ESTERROR | MOD_STATUS | MOD_TIMECONST)
2585
2586 /*
2587 * We initialize the structure for the ntp_adjtime()
2588 * system call. We have to convert everything to
2589 * microseconds or nanoseconds first. Do not update the
2590 * system variables if the ext_enable flag is set. In
2591 * this case, the external clock driver will update the
2592 * variables, which will be read later by the local
2593 * clock driver. Afterwards, remember the time and
2594 * frequency offsets for jitter and stability values and
2595 * to update the frequency file.
2596 */
2597 memset(&ntv, 0, sizeof(ntv));
2598 if (ext_enable) {
2599 ntv.modes = MOD_STATUS;
2600 } else {
2601#ifdef STA_NANO
2602 ntv.modes = MOD_BITS | MOD_NANO;
2603#else /* STA_NANO */
2604 ntv.modes = MOD_BITS;
2605#endif /* STA_NANO */
2606 if (clock_offset < 0)
2607 dtemp = -.5;
2608 else
2609 dtemp = .5;
2610#ifdef STA_NANO
2611 ntv.offset = (int32)(clock_offset * 1e9 + dtemp);
2612 ntv.constant = sys_poll;
2613#else /* STA_NANO */
2614 ntv.offset = (int32)(clock_offset * 1e6 + dtemp);
2615 ntv.constant = sys_poll - 4;
2616#endif /* STA_NANO */
2617 ntv.esterror = (u_int32)(clock_jitter * 1e6);
2618 ntv.maxerror = (u_int32)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
2619 ntv.status = STA_PLL;
2620
2621 /*
2622 * Enable/disable the PPS if requested.
2623 */
2624 if (pps_enable) {
2625 if (!(pll_status & STA_PPSTIME))
2626 report_event(EVNT_KERN,
Denys Vlasenko69675782013-01-14 01:34:48 +01002627 NULL, "PPS enabled");
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002628 ntv.status |= STA_PPSTIME | STA_PPSFREQ;
2629 } else {
2630 if (pll_status & STA_PPSTIME)
2631 report_event(EVNT_KERN,
Denys Vlasenko69675782013-01-14 01:34:48 +01002632 NULL, "PPS disabled");
2633 ntv.status &= ~(STA_PPSTIME | STA_PPSFREQ);
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002634 }
2635 if (sys_leap == LEAP_ADDSECOND)
2636 ntv.status |= STA_INS;
2637 else if (sys_leap == LEAP_DELSECOND)
2638 ntv.status |= STA_DEL;
2639 }
2640
2641 /*
2642 * Pass the stuff to the kernel. If it squeals, turn off
2643 * the pps. In any case, fetch the kernel offset,
2644 * frequency and jitter.
2645 */
2646 if (ntp_adjtime(&ntv) == TIME_ERROR) {
2647 if (!(ntv.status & STA_PPSSIGNAL))
2648 report_event(EVNT_KERN, NULL,
Denys Vlasenko69675782013-01-14 01:34:48 +01002649 "PPS no signal");
Denys Vlasenkodd6673b2010-01-01 16:46:17 +01002650 }
2651 pll_status = ntv.status;
2652#ifdef STA_NANO
2653 clock_offset = ntv.offset / 1e9;
2654#else /* STA_NANO */
2655 clock_offset = ntv.offset / 1e6;
2656#endif /* STA_NANO */
2657 clock_frequency = FREQTOD(ntv.freq);
2658
2659 /*
2660 * If the kernel PPS is lit, monitor its performance.
2661 */
2662 if (ntv.status & STA_PPSTIME) {
2663#ifdef STA_NANO
2664 clock_jitter = ntv.jitter / 1e9;
2665#else /* STA_NANO */
2666 clock_jitter = ntv.jitter / 1e6;
2667#endif /* STA_NANO */
2668 }
2669
2670#if defined(STA_NANO) && NTP_API == 4
2671 /*
2672 * If the TAI changes, update the kernel TAI.
2673 */
2674 if (loop_tai != sys_tai) {
2675 loop_tai = sys_tai;
2676 ntv.modes = MOD_TAI;
2677 ntv.constant = sys_tai;
2678 ntp_adjtime(&ntv);
2679 }
2680#endif /* STA_NANO */
2681 }
2682#endif /* KERNEL_PLL */
2683#endif