1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __BPF_RAND__
3#define __BPF_RAND__
4
5#include <stdint.h>
6#include <stdlib.h>
7#include <time.h>
8
9static inline uint64_t bpf_rand_mask(uint64_t mask)
10{
11	return (((uint64_t)(uint32_t)rand()) |
12	        ((uint64_t)(uint32_t)rand() << 32)) & mask;
13}
14
15#define bpf_rand_ux(x, m)			\
16static inline uint64_t bpf_rand_u##x(int shift)	\
17{						\
18	return bpf_rand_mask((m)) << shift;	\
19}
20
21bpf_rand_ux( 8,               0xffULL)
22bpf_rand_ux(16,             0xffffULL)
23bpf_rand_ux(24,           0xffffffULL)
24bpf_rand_ux(32,         0xffffffffULL)
25bpf_rand_ux(40,       0xffffffffffULL)
26bpf_rand_ux(48,     0xffffffffffffULL)
27bpf_rand_ux(56,   0xffffffffffffffULL)
28bpf_rand_ux(64, 0xffffffffffffffffULL)
29
30static inline void bpf_semi_rand_init(void)
31{
32	srand(time(NULL));
33}
34
35static inline uint64_t bpf_semi_rand_get(void)
36{
37	switch (rand() % 39) {
38	case  0: return 0x000000ff00000000ULL | bpf_rand_u8(0);
39	case  1: return 0xffffffff00000000ULL | bpf_rand_u16(0);
40	case  2: return 0x00000000ffff0000ULL | bpf_rand_u16(0);
41	case  3: return 0x8000000000000000ULL | bpf_rand_u32(0);
42	case  4: return 0x00000000f0000000ULL | bpf_rand_u32(0);
43	case  5: return 0x0000000100000000ULL | bpf_rand_u24(0);
44	case  6: return 0x800ff00000000000ULL | bpf_rand_u32(0);
45	case  7: return 0x7fffffff00000000ULL | bpf_rand_u32(0);
46	case  8: return 0xffffffffffffff00ULL ^ bpf_rand_u32(24);
47	case  9: return 0xffffffffffffff00ULL | bpf_rand_u8(0);
48	case 10: return 0x0000000010000000ULL | bpf_rand_u32(0);
49	case 11: return 0xf000000000000000ULL | bpf_rand_u8(0);
50	case 12: return 0x0000f00000000000ULL | bpf_rand_u8(8);
51	case 13: return 0x000000000f000000ULL | bpf_rand_u8(16);
52	case 14: return 0x0000000000000f00ULL | bpf_rand_u8(32);
53	case 15: return 0x00fff00000000f00ULL | bpf_rand_u8(48);
54	case 16: return 0x00007fffffffffffULL ^ bpf_rand_u32(1);
55	case 17: return 0xffff800000000000ULL | bpf_rand_u8(4);
56	case 18: return 0xffff800000000000ULL | bpf_rand_u8(20);
57	case 19: return (0xffffffc000000000ULL + 0x80000ULL) | bpf_rand_u32(0);
58	case 20: return (0xffffffc000000000ULL - 0x04000000ULL) | bpf_rand_u32(0);
59	case 21: return 0x0000000000000000ULL | bpf_rand_u8(55) | bpf_rand_u32(20);
60	case 22: return 0xffffffffffffffffULL ^ bpf_rand_u8(3) ^ bpf_rand_u32(40);
61	case 23: return 0x0000000000000000ULL | bpf_rand_u8(bpf_rand_u8(0) % 64);
62	case 24: return 0x0000000000000000ULL | bpf_rand_u16(bpf_rand_u8(0) % 64);
63	case 25: return 0xffffffffffffffffULL ^ bpf_rand_u8(bpf_rand_u8(0) % 64);
64	case 26: return 0xffffffffffffffffULL ^ bpf_rand_u40(bpf_rand_u8(0) % 64);
65	case 27: return 0x0000800000000000ULL;
66	case 28: return 0x8000000000000000ULL;
67	case 29: return 0x0000000000000000ULL;
68	case 30: return 0xffffffffffffffffULL;
69	case 31: return bpf_rand_u16(bpf_rand_u8(0) % 64);
70	case 32: return bpf_rand_u24(bpf_rand_u8(0) % 64);
71	case 33: return bpf_rand_u32(bpf_rand_u8(0) % 64);
72	case 34: return bpf_rand_u40(bpf_rand_u8(0) % 64);
73	case 35: return bpf_rand_u48(bpf_rand_u8(0) % 64);
74	case 36: return bpf_rand_u56(bpf_rand_u8(0) % 64);
75	case 37: return bpf_rand_u64(bpf_rand_u8(0) % 64);
76	default: return bpf_rand_u64(0);
77	}
78}
79
80#endif /* __BPF_RAND__ */
81