2d4e511ca2
Update ntp-4.2.8p13 --> 4.2.8p14. The advisory can be found at: http://support.ntp.org/bin/view/Main/SecurityNotice#\ March_2020_ntp_4_2_8p14_NTP_Rele No CVEs have been documented yet. MFC after: now Security: http://support.ntp.org/bin/view/Main/NtpBug3610 http://support.ntp.org/bin/view/Main/NtpBug3596 http://support.ntp.org/bin/view/Main/NtpBug3592
278 lines
11 KiB
C
278 lines
11 KiB
C
/*
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* ntp_leapsec.h - leap second processing for NTPD
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*
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* Written by Juergen Perlinger (perlinger@ntp.org) for the NTP project.
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* The contents of 'html/copyright.html' apply.
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* ----------------------------------------------------------------------
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* This is an attempt to get the leap second handling into a dedicated
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* module to make the somewhat convoluted logic testable.
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*/
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#ifndef NTP_LEAPSEC_H
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#define NTP_LEAPSEC_H
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struct stat;
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/* function pointer types. Note that 'fprintf' and 'getc' can be casted
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* to the dumper resp. reader type, provided the auxiliary argument is a
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* valid FILE pointer in hat case.
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*/
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typedef void (*leapsec_dumper)(void*, const char *fmt, ...);
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typedef int (*leapsec_reader)(void*);
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struct leap_table;
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typedef struct leap_table leap_table_t;
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/* Validate a stream containing a leap second file in the NIST / NTPD
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* format that can also be loaded via 'leapsec_load()'. This uses
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* the SHA1 hash and preprocessing as described in the NIST leapsecond
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* file.
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*/
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#define LSVALID_GOODHASH 1 /* valid signature */
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#define LSVALID_NOHASH 0 /* no signature in file */
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#define LSVALID_BADHASH -1 /* signature mismatch */
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#define LSVALID_BADFORMAT -2 /* signature not parseable */
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extern int leapsec_validate(leapsec_reader, void*);
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/* Set/get electric mode
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* Electric mode is defined as the operation mode where the system clock
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* automagically manages the leap second, so we don't have to care about
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* stepping the clock. (This should be the case with most systems,
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* including the current implementation of the Win32 timekeeping.)
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*
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* The consequence of electric mode is that we do not 'see' the leap
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* second, and no client actions are needed when crossing the leap era
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* boundary. In manual (aka non-electric) mode the clock will simply
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* step forward untill *we* (that is, this module) tells the client app
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* to step at the right time. This needs a slightly different type of
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* processing, so switching between those two modes should not be done
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* too close to a leap second. The transition might be lost in that
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* case. (The limit is actual 2 sec before transition.)
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*
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* OTOH, this is a system characteristic, so it's expected to be set
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* properly somewhere after system start and retain the value.
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*
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* Simply querying the state or setting it to the same value as before
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* does not have any unwanted side effects. You can query by giving a
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* negative value for the switch.
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*/
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extern int/*BOOL*/ leapsec_electric(int/*BOOL*/ on);
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/* Query result for a leap era. This is the minimal stateless
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* information available for a time stamp in UTC.
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*/
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struct leap_era {
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vint64 ebase; /* era base (UTC of start) */
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vint64 ttime; /* era end (UTC of next leap second) */
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int16_t taiof; /* offset to TAI in this era */
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};
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typedef struct leap_era leap_era_t;
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/* Query result for a leap second schedule
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* 'ebase' is the nominal UTC time when the current leap era
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* started. (Era base time)
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* 'ttime' is the next transition point in full time scale. (Nominal UTC
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* time when the next leap era starts.)
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* 'ddist' is the distance to the transition, in clock seconds.
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* This is the distance to the due time, which is different
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* from the transition time if the mode is non-electric.
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* Only valid if 'tai_diff' is not zero.
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* 'tai_offs' is the CURRENT distance from clock (UTC) to TAI. Always
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* valid.
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* 'tai_diff' is the change in TAI offset after the next leap
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* transition. Zero if nothing is pending or too far ahead.
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* 'warped' is set only once, when the the leap second occurred between
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* two queries. Always zero in electric mode. If non-zero,
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* immediately step the clock.
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* 'proximity' is a proximity warning. See definitions below. This is
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* more useful than an absolute difference to the leap second.
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* 'dynamic' != 0 if entry was requested by clock/peer
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*/
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struct leap_result {
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vint64 ebase;
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vint64 ttime;
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uint32_t ddist;
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int16_t tai_offs;
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int16_t tai_diff;
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int16_t warped;
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uint8_t proximity;
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uint8_t dynamic;
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};
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typedef struct leap_result leap_result_t;
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/* The leap signature is used in two distinct circumstances, and it has
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* slightly different content in these cases:
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* - it is used to indictae the time range covered by the leap second
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* table, and then it contains the last transition, TAI offset after
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* the final transition, and the expiration time.
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* - it is used to query data for AUTOKEY updates, and then it contains
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* the *current* TAI offset, the *next* transition time and the
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* expiration time of the table.
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*/
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struct leap_signature {
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uint32_t etime; /* expiration time */
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uint32_t ttime; /* transition time */
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int16_t taiof; /* total offset to TAI */
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};
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typedef struct leap_signature leap_signature_t;
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#ifdef LEAP_SMEAR
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struct leap_smear_info {
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int enabled; /* not 0 if smearing is generally enabled */
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int in_progress; /* not 0 if smearing is in progress, i.e. the offset has been computed */
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int leap_occurred; /* not 0 if the leap second has already occurred, i.e., during the leap second */
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double doffset; /* the current smear offset as double */
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l_fp offset; /* the current smear offset */
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uint32_t t_offset; /* the current time for which a smear offset has been computed */
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long interval; /* smear interval, in [s], should be at least some hours */
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double intv_start; /* start time of the smear interval */
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double intv_end; /* end time of the smear interval */
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};
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typedef struct leap_smear_info leap_smear_info_t;
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#endif /* LEAP_SMEAR */
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#define LSPROX_NOWARN 0 /* clear radar screen */
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#define LSPROX_SCHEDULE 1 /* less than 1 month to target*/
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#define LSPROX_ANNOUNCE 2 /* less than 1 day to target */
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#define LSPROX_ALERT 3 /* less than 10 sec to target */
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/* Get the current or alternate table pointer. Getting the alternate
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* pointer will automatically copy the primary table, so it can be
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* subsequently modified.
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*/
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extern leap_table_t *leapsec_get_table(int alternate);
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/* Set the current leap table. Accepts only return values from
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* 'leapsec_get_table()', so it's hard to do something wrong. Returns
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* TRUE if the current table is the requested one.
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*/
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extern int/*BOOL*/ leapsec_set_table(leap_table_t *);
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/* Clear all leap second data. Use it for init & cleanup */
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extern void leapsec_clear(leap_table_t*);
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/* Load a leap second file. If 'blimit' is set, do not store (but
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* register with their TAI offset) leap entries before the build date.
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* Update the leap signature data on the fly.
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*/
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extern int/*BOOL*/ leapsec_load(leap_table_t*, leapsec_reader,
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void*, int blimit);
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/* Dump the current leap table in readable format, using the provided
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* dump formatter function.
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*/
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extern void leapsec_dump(const leap_table_t*, leapsec_dumper func, void *farg);
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/* Read a leap second file from stream. This is a convenience wrapper
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* around the generic load function, 'leapsec_load()'.
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*/
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extern int/*BOOL*/ leapsec_load_stream(FILE * fp, const char * fname,
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int/*BOOL*/logall, int/*BOOL*/vhash);
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/* Read a leap second file from file. It checks that the file exists and
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* (if 'force' is not applied) the ctime/mtime has changed since the
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* last load. If the file has to be loaded, either due to 'force' or
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* changed time stamps, the 'stat()' results of the file are stored in
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* '*sb' for the next cycle. Returns TRUE on successful load, FALSE
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* otherwise. Uses 'leapsec_load_stream()' internally.
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*/
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extern int/*BOOL*/ leapsec_load_file(const char * fname, struct stat * sb,
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int/*BOOL*/force, int/*BOOL*/logall,
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int/*BOOL*/vhash);
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/* Get the current leap data signature. This consists of the last
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* ransition, the table expiration, and the total TAI difference at the
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* last transition. This is valid even if the leap transition itself was
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* culled due to the build date limit.
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*/
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extern void leapsec_getsig(leap_signature_t * psig);
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/* Check if the leap table is expired at the given time.
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*/
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extern int/*BOOL*/ leapsec_expired(uint32_t when, const time_t * pivot);
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/* Get the distance to expiration in days.
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* Returns negative values if expired, zero if there are less than 24hrs
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* left, and positive numbers otherwise.
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*/
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extern int32_t leapsec_daystolive(uint32_t when, const time_t * pivot);
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/* Reset the current leap frame, so the next query will do proper table
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* lookup from fresh. Suppresses a possible leap era transition detection
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* for the next query.
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*/
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extern void leapsec_reset_frame(void);
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#if 0 /* currently unused -- possibly revived later */
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/* Given a transition time, the TAI offset valid after that and an
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* expiration time, try to establish a system leap transition. Only
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* works if the existing table is extended. On success, updates the
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* signature data.
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*/
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extern int/*BOOL*/ leapsec_add_fix(int offset, uint32_t ttime, uint32_t etime,
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const time_t * pivot);
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#endif
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/* Take a time stamp and create a leap second frame for it. This will
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* schedule a leap second for the beginning of the next month, midnight
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* UTC. The 'insert' argument tells if a leap second is added (!=0) or
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* removed (==0). We do not handle multiple inserts (yet?)
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*
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* Returns 1 if the insert worked, 0 otherwise. (It's not possible to
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* insert a leap second into the current history -- only appending
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* towards the future is allowed!)
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*
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* 'ntp_now' is subject to era unfolding. The entry is marked
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* dynamic. The leap signature is NOT updated.
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*/
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extern int/*BOOL*/ leapsec_add_dyn(int/*BOOL*/ insert, uint32_t ntp_now,
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const time_t * pivot);
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/* Take a time stamp and get the associated leap information. The time
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* stamp is subject to era unfolding around the pivot or the current
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* system time if pivot is NULL. Sets the information in '*qr' and
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* returns TRUE if a leap second era boundary was crossed between the
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* last and the current query. In that case, qr->warped contains the
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* required clock stepping, which is always zero in electric mode.
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*/
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extern int/*BOOL*/ leapsec_query(leap_result_t * qr, uint32_t ntpts,
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const time_t * pivot);
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/* For a given time stamp, fetch the data for the bracketing leap
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* era. The time stamp is subject to NTP era unfolding.
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*/
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extern int/*BOOL*/ leapsec_query_era(leap_era_t * qr, uint32_t ntpts,
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const time_t * pivot);
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/* Get the current leap frame info. Returns TRUE if the result contains
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* useable data, FALSE if there is currently no leap second frame.
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* This merely replicates some results from a previous query, but since
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* it does not check the current time, only the following entries are
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* meaningful:
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* qr->ttime;
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* qr->tai_offs;
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* qr->tai_diff;
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* qr->dynamic;
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*/
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extern int/*BOOL*/ leapsec_frame(leap_result_t *qr);
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/* Process a AUTOKEY TAI offset information. This *might* augment the
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* current leap data table with the given TAI offset.
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* Returns TRUE if action was taken, FALSE otherwise.
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*/
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extern int/*BOOL*/ leapsec_autokey_tai(int tai_offset, uint32_t ntpnow,
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const time_t * pivot);
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/* reset global state for unit tests */
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extern void leapsec_ut_pristine(void);
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#endif /* !defined(NTP_LEAPSEC_H) */
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