1 files changed, 87 insertions, 0 deletions
diff --git a/src/rust/external/crypto_rand.rs b/src/rust/external/crypto_rand.rs
new file mode 100644
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+++ b/src/rust/external/crypto_rand.rs
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+// Copyright (c) 2018, The Tor Project, Inc.
+// Copyright (c) 2018, isis agora lovecruft
+// See LICENSE for licensing information
+
+//! Bindings to external (P)RNG interfaces and utilities in 
+//! src/common/crypto_rand.[ch].
+//!
+//! We wrap our C implementations in src/common/crypto_rand.[ch] here in order
+//! to provide wrappers with native Rust types, and then provide more Rusty
+//! types and and trait implementations in src/rust/crypto/rand/.
+
+use std::time::Duration;
+
+use libc::c_double;
+use libc::c_int;
+use libc::size_t;
+use libc::time_t;
+use libc::uint8_t;
+
+extern "C" {
+    fn crypto_seed_rng() -> c_int;
+    fn crypto_rand(out: *mut uint8_t, out_len: size_t);
+    fn crypto_strongest_rand(out: *mut uint8_t, out_len: size_t);
+    fn crypto_rand_time_range(min: time_t, max: time_t) -> time_t;
+    fn crypto_rand_double() -> c_double;
+}
+
+/// Seed OpenSSL's random number generator with bytes from the operating
+/// system.
+///
+/// # Returns
+///
+/// `true` on success; `false` on failure.
+pub fn c_tor_crypto_seed_rng() -> bool {
+    let ret: c_int;
+
+    unsafe {
+        ret = crypto_seed_rng();
+    }
+    match ret {
+        0 => return true,
+        _ => return false,
+    }
+}
+
+/// Fill the bytes of `dest` with random data.
+pub fn c_tor_crypto_rand(dest: &mut [u8]) {
+    unsafe {
+        crypto_rand(dest.as_mut_ptr(), dest.len() as size_t);
+    }
+}
+
+/// Fill the bytes of `dest` with "strong" random data by hashing
+/// together randomness obtained from OpenSSL's RNG and the operating
+/// system.
+pub fn c_tor_crypto_strongest_rand(dest: &mut [u8]) {
+    // We'll let the C side panic if the len is larger than
+    // MAX_STRONGEST_RAND_SIZE, rather than potentially panicking here.  A
+    // paranoid caller should assert on the length of dest *before* calling this
+    // function.
+    unsafe {
+        crypto_strongest_rand(dest.as_mut_ptr(), dest.len() as size_t);
+    }
+}
+
+/// Get a random time, in seconds since the Unix Epoch.
+///
+/// # Returns
+///
+/// A `std::time::Duration` of seconds since the Unix Epoch.
+pub fn c_tor_crypto_rand_time_range(min: &Duration, max: &Duration) -> Duration {
+    let ret: time_t;
+
+    unsafe {
+        ret = crypto_rand_time_range(min.as_secs() as time_t, max.as_secs() as time_t);
+    }
+
+    Duration::from_secs(ret as u64)
+}
+
+/// Return a pseudorandom 64-bit float, chosen uniformly from the range [0.0, 1.0).
+pub fn c_tor_crypto_rand_double() -> f64 {
+    unsafe {
+        crypto_rand_double()
+    }
+}
+