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Commit	Line	Data
	1	/*
	2	* Copyright (c) 2017-2018 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28
	29	#include <netinet/in_stat.h>
	30
	31	#define IN_STAT_ACTIVITY_GRANULARITY 8 /* 8 sec granularity */
	32	#define IN_STAT_ACTIVITY_TIME_SEC_SHIFT 3 /* 8 sec per bit */
	33	#define IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE ((uint64_t) 128)
	34	#define IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE ((uint64_t) 64)
	35	#define IN_STAT_ACTIVITY_TOTAL_TIME ((uint64_t) (8 * 128))
	36	#define IN_STAT_SET_MOST_SIGNIFICANT_BIT ((u_int64_t )0x8000000000000000)
	37
	38	void
	39	in_stat_set_activity_bitmap(activity_bitmap_t *activity, uint64_t now)
	40	{
	41	uint64_t elapsed_time, slot;
	42	uint64_t *bitmap;
	43	if (activity->start == 0) {
	44	// Align all activity maps
	45	activity->start = now - (now % IN_STAT_ACTIVITY_GRANULARITY);
	46	}
	47	elapsed_time = now - activity->start;
	48
	49	slot = elapsed_time >> IN_STAT_ACTIVITY_TIME_SEC_SHIFT;
	50	if (slot < IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE) {
	51	if (slot < IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
	52	bitmap = &activity->bitmap[0];
	53	} else {
	54	bitmap = &activity->bitmap[1];
	55	slot -= IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE;
	56	}
	57	*bitmap \|= (((u_int64_t) 1) << slot);
	58	} else {
	59	if (slot >= (IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE * 2)) {
	60	activity->start = now - IN_STAT_ACTIVITY_TOTAL_TIME;
	61	activity->bitmap[0] = activity->bitmap[1] = 0;
	62	} else {
	63	uint64_t shift =
	64	slot - (IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE - 1);
	65	/*
	66	* Move the start time and bitmap forward to
	67	* cover the lost time
	68	*/
	69	activity->start +=
	70	(shift << IN_STAT_ACTIVITY_TIME_SEC_SHIFT);
	71	if (shift > IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
	72	activity->bitmap[0] = activity->bitmap[1];
	73	activity->bitmap[1] = 0;
	74	shift -= IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE;
	75	if (shift == IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
	76	activity->bitmap[0] = 0;
	77	} else {
	78	activity->bitmap[0] >>= shift;
	79	}
	80	} else {
	81	uint64_t mask_lower, tmp;
	82	uint64_t b1_low, b0_high;
	83
	84	/*
	85	* generate a mask with all of lower
	86	* 'shift' bits set
	87	*/
	88	tmp = (((uint64_t)1) << (shift - 1));
	89	mask_lower = ((tmp - 1) ^ tmp);
	90	activity->bitmap[0] >>= shift;
	91	b1_low = (activity->bitmap[1] & mask_lower);
	92
	93	b0_high = (b1_low <<
	94	(IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE -
	95	shift));
	96	activity->bitmap[0] \|= b0_high;
	97	activity->bitmap[1] >>= shift;
	98	}
	99	}
	100	activity->bitmap[1] \|= IN_STAT_SET_MOST_SIGNIFICANT_BIT;
	101	}
	102	}