2  * ntp_monitor - monitor ntpd statistics
22  * Record statistics based on source address, mode and version. The
27  * Each entry is doubly linked into two lists, a hash table and a most-
28  * recently-used (MRU) list. When a packet arrives it is looked up in
68  * List of free structures structures, and counters of in-use and total
82  * headway is less than the minimum, as well as if the average headway
87 u_char	ntp_minpoll = NTP_MINPOLL;	/* minimum average log2 seconds */
108  * init_mon - initialize monitoring global data
123  * remove_from_hash - removes an entry from the address hash table and
134 	mru_entries--;  in remove_from_hash()
135 	hash = MON_HASH(&mon->rmtadr);  in remove_from_hash()
153  * mon_reclaim_entry - Remove an entry from the MRU list and from the
154  *		       hash array, then zero-initialize it.  Indirectly
175  * mon_getmoremem - get more memory and put it on the free list
190 		for (chunk += entries; entries; entries--)  in mon_getmoremem()
191 			mon_free_entry(--chunk);  in mon_getmoremem()
199  * mon_start - start up the monitoring software
218 	 * Select the MRU hash table size to limit the average count  in mon_start()
236  * mon_stop - stop the monitoring software
255 	 * Move everything on the MRU list to the free list quickly,  in mon_stop()
271  * mon_clearinterface -- remove mru entries referring to a local address
283 		if (mon->lcladr == lcladr) {  in mon_clearinterface()
288 			/* put on free list */  in mon_clearinterface()
296  * ntp_monitor - record stats about this packet
306  * such responses.  ntpdc -c reslist lets you see whether RES_LIMITED
328 	int		limit;		/* average threshold */  in ntp_monitor()
335 	pkt = &rbufp->recv_pkt;  in ntp_monitor()
336 	hash = MON_HASH(&rbufp->recv_srcadr);  in ntp_monitor()
337 	mode = PKT_MODE(pkt->li_vn_mode);  in ntp_monitor()
338 	version = PKT_VERSION(pkt->li_vn_mode);  in ntp_monitor()
346 	for (; mon != NULL; mon = mon->hash_next) {  in ntp_monitor()
347 		if (SOCK_EQ(&mon->rmtadr, &rbufp->recv_srcadr)) {  in ntp_monitor()
352 		interval_fp = rbufp->recv_time;  in ntp_monitor()
353 		L_SUB(&interval_fp, &mon->last);  in ntp_monitor()
354 		/* add one-half second to round up */  in ntp_monitor()
357 		mon->last = rbufp->recv_time;  in ntp_monitor()
358 		NSRCPORT(&mon->rmtadr) = NSRCPORT(&rbufp->recv_srcadr);  in ntp_monitor()
359 		mon->count++;  in ntp_monitor()
361 		mon->vn_mode = VN_MODE(version, mode);  in ntp_monitor()
372 		mon->leak -= interval;  in ntp_monitor()
373 		mon->leak = max(0, mon->leak);  in ntp_monitor()
375 		leak = mon->leak + head;  in ntp_monitor()
382 		 * If the minimum and average thresholds are not  in ntp_monitor()
385 		 * that we give a 1-s grace for the minimum threshold  in ntp_monitor()
386 		 * and a 2-s grace for the headway increment.  If one or  in ntp_monitor()
388 		 * less than the average threshold, set the counter to  in ntp_monitor()
389 		 * the average threshold plus the increment and leave  in ntp_monitor()
392 		 * This rate-limits the KoDs to no more often than the  in ntp_monitor()
393 		 * average headway.  in ntp_monitor()
396 			mon->leak = leak - 2;  in ntp_monitor()
398 		} else if (mon->leak < limit) {  in ntp_monitor()
399 			mon->leak = limit + head;  in ntp_monitor()
403 		mon->flags = restrict_mask;  in ntp_monitor()
405 		return mon->flags;  in ntp_monitor()
415 	 * - mru_mindepth ("mru mindepth") is a floor beneath which  in ntp_monitor()
418 	 *   limit on the total number of entries.  in ntp_monitor()
419 	 * - mru_maxage ("mru maxage") is a ceiling on the age in  in ntp_monitor()
424 	 * - mru_maxdepth ("mru maxdepth") is a hard limit on the  in ntp_monitor()
426 	 * - "mru maxmem" sets mru_maxdepth to the number of entries  in ntp_monitor()
429 	 * - mru_initalloc ("mru initalloc" sets the count of the  in ntp_monitor()
431 	 * - "mru initmem" sets mru_initalloc in units of kilobytes.  in ntp_monitor()
433 	 * - mru_incalloc ("mru incalloc" sets the number of entries to  in ntp_monitor()
434 	 *   allocate on-demand each time the free list is empty.  in ntp_monitor()
435 	 * - "mru incmem" sets mru_incalloc in units of kilobytes.  in ntp_monitor()
449 			interval_fp = rbufp->recv_time;  in ntp_monitor()
450 			L_SUB(&interval_fp, &oldest->last);  in ntp_monitor()
451 			/* add one-half second to round up */  in ntp_monitor()
455 		/* note -1 is legal for mru_maxage (disables) */  in ntp_monitor()
481 	mon->last = rbufp->recv_time;  in ntp_monitor()
482 	mon->first = mon->last;  in ntp_monitor()
483 	mon->count = 1;  in ntp_monitor()
484 	mon->flags = ~(RES_LIMITED | RES_KOD) & flags;  in ntp_monitor()
485 	mon->leak = 0;  in ntp_monitor()
486 	memcpy(&mon->rmtadr, &rbufp->recv_srcadr, sizeof(mon->rmtadr));  in ntp_monitor()
487 	mon->vn_mode = VN_MODE(version, mode);  in ntp_monitor()
488 	mon->lcladr = rbufp->dstadr;  in ntp_monitor()
489 	mon->cast_flags = (u_char)(((rbufp->dstadr->flags &  in ntp_monitor()
490 	    INT_MCASTOPEN) && rbufp->fd == mon->lcladr->fd) ? MDF_MCAST  in ntp_monitor()
491 	    : rbufp->fd == mon->lcladr->bfd ? MDF_BCAST : MDF_UCAST);  in ntp_monitor()
494 	 * Drop him into front of the hash table. Also put him on top of  in ntp_monitor()
500 	return mon->flags;  in ntp_monitor()