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 
9 static 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)			\
16 static inline uint64_t bpf_rand_u##x(int shift)	\
17 {						\
18 	return bpf_rand_mask((m)) << shift;	\
19 }
20 
21 bpf_rand_ux( 8,               0xffULL)
22 bpf_rand_ux(16,             0xffffULL)
23 bpf_rand_ux(24,           0xffffffULL)
24 bpf_rand_ux(32,         0xffffffffULL)
25 bpf_rand_ux(40,       0xffffffffffULL)
26 bpf_rand_ux(48,     0xffffffffffffULL)
27 bpf_rand_ux(56,   0xffffffffffffffULL)
28 bpf_rand_ux(64, 0xffffffffffffffffULL)
29 
30 static inline void bpf_semi_rand_init(void)
31 {
32 	srand(time(NULL));
33 }
34 
35 static 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