1 /*
2 * Copyright (c) 2017-2024 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 <string.h>
30 #include <netinet/in_stat.h>
31
32 #define IN_STAT_ACTIVITY_GRANULARITY 8 /* 8 sec granularity */
33 #define IN_STAT_ACTIVITY_TIME_SEC_SHIFT 3 /* 8 sec per bit */
34 #define IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE ((uint64_t) 128)
35 #define IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE ((uint64_t) 64)
36 #define IN_STAT_ACTIVITY_TOTAL_TIME ((uint64_t) (8 * 128))
37 #define IN_STAT_SET_MOST_SIGNIFICANT_BIT ((u_int64_t )0x8000000000000000)
38
39 void
in_stat_set_activity_bitmap(activity_bitmap_t * activity,uint64_t now)40 in_stat_set_activity_bitmap(activity_bitmap_t *activity, uint64_t now)
41 {
42 uint64_t elapsed_time, slot;
43 uint64_t *bitmap;
44 if (activity->start == 0) {
45 // Align all activity maps
46 activity->start = now - (now % IN_STAT_ACTIVITY_GRANULARITY);
47 }
48 elapsed_time = now - activity->start;
49
50 slot = elapsed_time >> IN_STAT_ACTIVITY_TIME_SEC_SHIFT;
51 if (slot < IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE) {
52 if (slot < IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
53 bitmap = &activity->bitmap[0];
54 } else {
55 bitmap = &activity->bitmap[1];
56 slot -= IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE;
57 }
58 *bitmap |= (((u_int64_t) 1) << slot);
59 } else {
60 if (slot >= (IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE * 2)) {
61 activity->start = now - IN_STAT_ACTIVITY_TOTAL_TIME;
62 activity->bitmap[0] = activity->bitmap[1] = 0;
63 } else {
64 uint64_t shift =
65 slot - (IN_STAT_ACTIVITY_BITMAP_TOTAL_SIZE - 1);
66 /*
67 * Move the start time and bitmap forward to
68 * cover the lost time
69 */
70 activity->start +=
71 (shift << IN_STAT_ACTIVITY_TIME_SEC_SHIFT);
72 if (shift > IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
73 activity->bitmap[0] = activity->bitmap[1];
74 activity->bitmap[1] = 0;
75 shift -= IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE;
76 if (shift == IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE) {
77 activity->bitmap[0] = 0;
78 } else {
79 activity->bitmap[0] >>= shift;
80 }
81 } else {
82 uint64_t mask_lower, tmp;
83 uint64_t b1_low, b0_high;
84
85 /*
86 * generate a mask with all of lower
87 * 'shift' bits set
88 */
89 tmp = (((uint64_t)1) << (shift - 1));
90 mask_lower = ((tmp - 1) ^ tmp);
91 activity->bitmap[0] >>= shift;
92 b1_low = (activity->bitmap[1] & mask_lower);
93
94 b0_high = (b1_low <<
95 (IN_STAT_ACTIVITY_BITMAP_FIELD_SIZE -
96 shift));
97 activity->bitmap[0] |= b0_high;
98 activity->bitmap[1] >>= shift;
99 }
100 }
101 activity->bitmap[1] |= IN_STAT_SET_MOST_SIGNIFICANT_BIT;
102 }
103 }
104