quiche/
rand.rs

1// Copyright (C) 2018-2019, Cloudflare, Inc.
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are
6// met:
7//
8//     * Redistributions of source code must retain the above copyright notice,
9//       this list of conditions and the following disclaimer.
10//
11//     * Redistributions in binary form must reproduce the above copyright
12//       notice, this list of conditions and the following disclaimer in the
13//       documentation and/or other materials provided with the distribution.
14//
15// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
16// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
17// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
19// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
23// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
24// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27pub fn rand_bytes(buf: &mut [u8]) {
28    unsafe {
29        RAND_bytes(buf.as_mut_ptr(), buf.len());
30    }
31}
32
33pub fn rand_u8() -> u8 {
34    let mut buf = [0; 1];
35
36    rand_bytes(&mut buf);
37
38    buf[0]
39}
40
41pub fn rand_u64() -> u64 {
42    let mut buf = [0; 8];
43
44    rand_bytes(&mut buf);
45
46    u64::from_ne_bytes(buf)
47}
48
49pub fn rand_u64_uniform(max: u64) -> u64 {
50    let chunk_size = u64::MAX / max;
51    let end_of_last_chunk = chunk_size * max;
52
53    let mut r = rand_u64();
54
55    while r >= end_of_last_chunk {
56        r = rand_u64();
57    }
58
59    r / chunk_size
60}
61
62extern "C" {
63    fn RAND_bytes(buf: *mut u8, len: libc::size_t) -> libc::c_int;
64}
quiche/rand.rs

quiche/
rand.rs
