/*
* get_systime - return system time in NTP timestamp format.
*/
void get_systime(l_fp *now) /* system time */
{
double dtemp;
struct timeval tv; /* seconds and microseconds */
/*
* Convert Unix timeval from seconds and microseconds to NTP
* seconds and fraction.
*/
gettimeofday(&tv, NULL);
now->l_i = tv.tv_sec + JAN_1970;
dtemp = 0;
if (sys_tick > FUZZ)
dtemp = ntp_random() * 2. / FRAC * sys_tick * 1e6;
else if (sys_tick > 0)
dtemp = ntp_random() * 2. / FRAC;
dtemp = (tv.tv_usec + dtemp) * 1e-6;
if (dtemp >= 1.) {
dtemp -= 1.;
now->l_i++;
} else if (dtemp < 0) {
dtemp += 1.;
now->l_i--;
}
now->l_uf = (uint32_t)(dtemp * FRAC);
}
/*
* init_peer - initialize peer data structures and counters
*
* N.B. We use the random number routine in here. It had better be
* initialized prior to getting here.
*/
void
init_peer(void)
{
int i;
/*
* Initialize peer free list from static allocation.
*/
for (i = COUNTOF(init_peer_alloc) - 1; i >= 0; i--)
LINK_SLIST(peer_free, &init_peer_alloc[i], p_link);
total_peer_structs = COUNTOF(init_peer_alloc);
peer_free_count = COUNTOF(init_peer_alloc);
/*
* Initialize our first association ID
*/
do
current_association_ID = ntp_random() & ASSOCID_MAX;
while (!current_association_ID);
}
/*
* init_peer - initialize peer data structures and counters
*
* N.B. We use the random number routine in here. It had better be
* initialized prior to getting here.
*/
void
init_peer(void)
{
register int i;
/*
* Clear hash table and counters.
*/
for (i = 0; i < NTP_HASH_SIZE; i++) {
peer_hash[i] = 0;
peer_hash_count[i] = 0;
assoc_hash[i] = 0;
assoc_hash_count[i] = 0;
}
/*
* Clear stat counters
*/
findpeer_calls = peer_allocations = 0;
assocpeer_calls = peer_demobilizations = 0;
/*
* Initialize peer memory.
*/
peer_free = 0;
for (i = 0; i < INIT_PEER_ALLOC; i++) {
init_peer_alloc[i].next = peer_free;
peer_free = &init_peer_alloc[i];
}
total_peer_structs = INIT_PEER_ALLOC;
peer_free_count = INIT_PEER_ALLOC;
/*
* Initialize our first association ID
*/
while ((current_association_ID = ntp_random() & 0xffff) == 0);
}
/*
* ntp_monitor - record stats about this packet
*
* Returns supplied restriction flags, with RES_LIMITED and RES_KOD
* cleared unless the packet should not be responded to normally
* (RES_LIMITED) and possibly should trigger a KoD response (RES_KOD).
* The returned flags are saved in the MRU entry, so that it reflects
* whether the last packet from that source triggered rate limiting,
* and if so, possible KoD response. This implies you can not tell
* whether a given address is eligible for rate limiting/KoD from the
* monlist restrict bits, only whether or not the last packet triggered
* such responses. ntpdc -c reslist lets you see whether RES_LIMITED
* or RES_KOD is lit for a particular address before ntp_monitor()'s
* typical dousing.
*/
u_short
ntp_monitor(
struct recvbuf *rbufp,
u_short flags
)
{
l_fp interval_fp;
struct pkt * pkt;
mon_entry * mon;
mon_entry * oldest;
int oldest_age;
u_int hash;
u_short restrict_mask;
u_char mode;
u_char version;
int interval;
int head; /* headway increment */
int leak; /* new headway */
int limit; /* average threshold */
REQUIRE(rbufp != NULL);
if (mon_enabled == MON_OFF)
return ~(RES_LIMITED | RES_KOD) & flags;
pkt = &rbufp->recv_pkt;
hash = MON_HASH(&rbufp->recv_srcadr);
mode = PKT_MODE(pkt->li_vn_mode);
version = PKT_VERSION(pkt->li_vn_mode);
mon = mon_hash[hash];
/*
* We keep track of all traffic for a given IP in one entry,
* otherwise cron'ed ntpdate or similar evades RES_LIMITED.
*/
for (; mon != NULL; mon = mon->hash_next)
if (SOCK_EQ(&mon->rmtadr, &rbufp->recv_srcadr))
break;
if (mon != NULL) {
interval_fp = rbufp->recv_time;
L_SUB(&interval_fp, &mon->last);
/* add one-half second to round up */
L_ADDUF(&interval_fp, 0x80000000);
interval = interval_fp.l_i;
mon->last = rbufp->recv_time;
NSRCPORT(&mon->rmtadr) = NSRCPORT(&rbufp->recv_srcadr);
mon->count++;
restrict_mask = flags;
mon->vn_mode = VN_MODE(version, mode);
/* Shuffle to the head of the MRU list. */
UNLINK_DLIST(mon, mru);
LINK_DLIST(mon_mru_list, mon, mru);
/*
* At this point the most recent arrival is first in the
* MRU list. Decrease the counter by the headway, but
* not less than zero.
*/
mon->leak -= interval;
mon->leak = max(0, mon->leak);
head = 1 << ntp_minpoll;
leak = mon->leak + head;
limit = NTP_SHIFT * head;
DPRINTF(2, ("MRU: interval %d headway %d limit %d\n",
interval, leak, limit));
/*
* If the minimum and average thresholds are not
* exceeded, douse the RES_LIMITED and RES_KOD bits and
* increase the counter by the headway increment. Note
* that we give a 1-s grace for the minimum threshold
* and a 2-s grace for the headway increment. If one or
* both thresholds are exceeded and the old counter is
* less than the average threshold, set the counter to
* the average threshold plus the increment and leave
* the RES_LIMITED and RES_KOD bits lit. Otherwise,
* leave the counter alone and douse the RES_KOD bit.
* This rate-limits the KoDs to no less than the average
* headway.
*/
if (interval + 1 >= ntp_minpkt && leak < limit) {
mon->leak = leak - 2;
restrict_mask &= ~(RES_LIMITED | RES_KOD);
} else if (mon->leak < limit)
mon->leak = limit + head;
else
restrict_mask &= ~RES_KOD;
mon->flags = restrict_mask;
return mon->flags;
}
/*
* If we got here, this is the first we've heard of this
* guy. Get him some memory, either from the free list
* or from the tail of the MRU list.
*
* The following ntp.conf "mru" knobs come into play determining
* the depth (or count) of the MRU list:
* - mru_mindepth ("mru mindepth") is a floor beneath which
* entries are kept without regard to their age. The
* default is 600 which matches the longtime implementation
* limit on the total number of entries.
* - mru_maxage ("mru maxage") is a ceiling on the age in
* seconds of entries. Entries older than this are
* reclaimed once mon_mindepth is exceeded. 64s default.
* Note that entries older than this can easily survive
* as they are reclaimed only as needed.
* - mru_maxdepth ("mru maxdepth") is a hard limit on the
* number of entries.
* - "mru maxmem" sets mru_maxdepth to the number of entries
* which fit in the given number of kilobytes. The default is
* 1024, or 1 megabyte.
* - mru_initalloc ("mru initalloc" sets the count of the
* initial allocation of MRU entries.
* - "mru initmem" sets mru_initalloc in units of kilobytes.
* The default is 4.
* - mru_incalloc ("mru incalloc" sets the number of entries to
* allocate on-demand each time the free list is empty.
* - "mru incmem" sets mru_incalloc in units of kilobytes.
* The default is 4.
* Whichever of "mru maxmem" or "mru maxdepth" occurs last in
* ntp.conf controls. Similarly for "mru initalloc" and "mru
* initmem", and for "mru incalloc" and "mru incmem".
*/
if (mru_entries < mru_mindepth) {
if (NULL == mon_free)
mon_getmoremem();
UNLINK_HEAD_SLIST(mon, mon_free, hash_next);
} else {
oldest = TAIL_DLIST(mon_mru_list, mru);
oldest_age = 0; /* silence uninit warning */
if (oldest != NULL) {
interval_fp = rbufp->recv_time;
L_SUB(&interval_fp, &oldest->last);
/* add one-half second to round up */
L_ADDUF(&interval_fp, 0x80000000);
oldest_age = interval_fp.l_i;
}
/* note -1 is legal for mru_maxage (disables) */
if (oldest != NULL && mru_maxage < oldest_age) {
mon_reclaim_entry(oldest);
mon = oldest;
} else if (mon_free != NULL || mru_alloc <
mru_maxdepth) {
if (NULL == mon_free)
mon_getmoremem();
UNLINK_HEAD_SLIST(mon, mon_free, hash_next);
/* Preempt from the MRU list if old enough. */
} else if (ntp_random() / (2. * FRAC) >
(double)oldest_age / mon_age) {
return ~(RES_LIMITED | RES_KOD) & flags;
} else {
mon_reclaim_entry(oldest);
mon = oldest;
}
}
INSIST(mon != NULL);
/*
* Got one, initialize it
*/
mru_entries++;
mru_peakentries = max(mru_peakentries, mru_entries);
mon->last = rbufp->recv_time;
mon->first = mon->last;
mon->count = 1;
mon->flags = ~(RES_LIMITED | RES_KOD) & flags;
mon->leak = 0;
memcpy(&mon->rmtadr, &rbufp->recv_srcadr, sizeof(mon->rmtadr));
mon->vn_mode = VN_MODE(version, mode);
mon->lcladr = rbufp->dstadr;
mon->cast_flags = (u_char)(((rbufp->dstadr->flags &
INT_MCASTOPEN) && rbufp->fd == mon->lcladr->fd) ? MDF_MCAST
: rbufp->fd == mon->lcladr->bfd ? MDF_BCAST : MDF_UCAST);
/*
* Drop him into front of the hash table. Also put him on top of
* the MRU list.
*/
LINK_SLIST(mon_hash[hash], mon, hash_next);
LINK_DLIST(mon_mru_list, mon, mru);
return mon->flags;
}
/*
* get_systime - return system time in NTP timestamp format.
*/
void
get_systime(
l_fp *now /* system time */
)
{
static struct timespec ts_prev; /* prior os time */
static l_fp lfp_prev; /* prior result */
static double dfuzz_prev; /* prior fuzz */
struct timespec ts; /* seconds and nanoseconds */
struct timespec ts_min; /* earliest permissible */
struct timespec ts_lam; /* lamport fictional increment */
struct timespec ts_prev_log; /* for msyslog only */
double dfuzz;
double ddelta;
l_fp result;
l_fp lfpfuzz;
l_fp lfpdelta;
get_ostime(&ts);
DEBUG_REQUIRE(systime_init_done);
ENTER_GET_SYSTIME_CRITSEC();
/*
* After default_get_precision() has set a nonzero sys_fuzz,
* ensure every reading of the OS clock advances by at least
* sys_fuzz over the prior reading, thereby assuring each
* fuzzed result is strictly later than the prior. Limit the
* necessary fiction to 1 second.
*/
if (!USING_SIGIO()) {
ts_min = add_tspec_ns(ts_prev, sys_fuzz_nsec);
if (cmp_tspec(ts, ts_min) < 0) {
ts_lam = sub_tspec(ts_min, ts);
if (ts_lam.tv_sec > 0 && !lamport_violated) {
msyslog(LOG_ERR,
"get_systime Lamport advance exceeds one second (%.9f)",
ts_lam.tv_sec +
1e-9 * ts_lam.tv_nsec);
exit(1);
}
if (!lamport_violated)
ts = ts_min;
}
ts_prev_log = ts_prev;
ts_prev = ts;
} else {
/*
* Quiet "ts_prev_log.tv_sec may be used uninitialized"
* warning from x86 gcc 4.5.2.
*/
ZERO(ts_prev_log);
}
/* convert from timespec to l_fp fixed-point */
result = tspec_stamp_to_lfp(ts);
/*
* Add in the fuzz.
*/
dfuzz = ntp_random() * 2. / FRAC * sys_fuzz;
DTOLFP(dfuzz, &lfpfuzz);
L_ADD(&result, &lfpfuzz);
/*
* Ensure result is strictly greater than prior result (ignoring
* sys_residual's effect for now) once sys_fuzz has been
* determined.
*/
if (!USING_SIGIO()) {
if (!L_ISZERO(&lfp_prev) && !lamport_violated) {
if (!L_ISGTU(&result, &lfp_prev) &&
sys_fuzz > 0.) {
msyslog(LOG_ERR, "ts_prev %s ts_min %s",
tspectoa(ts_prev_log),
tspectoa(ts_min));
msyslog(LOG_ERR, "ts %s", tspectoa(ts));
msyslog(LOG_ERR, "sys_fuzz %ld nsec, prior fuzz %.9f",
sys_fuzz_nsec, dfuzz_prev);
msyslog(LOG_ERR, "this fuzz %.9f",
dfuzz);
lfpdelta = lfp_prev;
L_SUB(&lfpdelta, &result);
LFPTOD(&lfpdelta, ddelta);
msyslog(LOG_ERR,
"prev get_systime 0x%x.%08x is %.9f later than 0x%x.%08x",
lfp_prev.l_ui, lfp_prev.l_uf,
ddelta, result.l_ui, result.l_uf);
}
}
lfp_prev = result;
dfuzz_prev = dfuzz;
if (lamport_violated)
lamport_violated = FALSE;
}
LEAVE_GET_SYSTIME_CRITSEC();
*now = result;
}
/*
* get_systime - return system time in NTP timestamp format.
*/
void
get_systime(
l_fp *now /* system time */
)
{
double dtemp;
#if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_GETCLOCK)
struct timespec ts; /* seconds and nanoseconds */
/*
* Convert Unix timespec from seconds and nanoseconds to NTP
* seconds and fraction.
*/
# ifdef HAVE_CLOCK_GETTIME
clock_gettime(CLOCK_REALTIME, &ts);
# else
getclock(TIMEOFDAY, &ts);
# endif
now->l_i = (int32)ts.tv_sec + JAN_1970;
dtemp = 0;
if (sys_tick > FUZZ)
dtemp = ntp_random() * 2. / FRAC * sys_tick * 1e9;
else if (sys_tick > 0)
dtemp = ntp_random() * 2. / FRAC;
dtemp = (ts.tv_nsec + dtemp) * 1e-9 + sys_residual;
if (dtemp >= 1.) {
dtemp -= 1.;
now->l_i++;
} else if (dtemp < 0) {
dtemp += 1.;
now->l_i--;
}
now->l_uf = (u_int32)(dtemp * FRAC);
#else /* HAVE_CLOCK_GETTIME || HAVE_GETCLOCK */
struct timeval tv; /* seconds and microseconds */
/*
* Convert Unix timeval from seconds and microseconds to NTP
* seconds and fraction.
*/
GETTIMEOFDAY(&tv, NULL);
now->l_i = tv.tv_sec + JAN_1970;
dtemp = 0;
if (sys_tick > FUZZ)
dtemp = ntp_random() * 2. / FRAC * sys_tick * 1e6;
else if (sys_tick > 0)
dtemp = ntp_random() * 2. / FRAC;
dtemp = (tv.tv_usec + dtemp) * 1e-6 + sys_residual;
if (dtemp >= 1.) {
dtemp -= 1.;
now->l_i++;
} else if (dtemp < 0) {
dtemp += 1.;
now->l_i--;
}
now->l_uf = (u_int32)(dtemp * FRAC);
#endif /* HAVE_CLOCK_GETTIME || HAVE_GETCLOCK */
}
