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
in_stat_set_activity_bitmap(activity_bitmap_t * activity,uint64_t now)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 }
103