openethereum/ethash/src/compute.rs
Andronik Ordian 5a131175e8
[ethash] remove mem::uninitialized (#10861)
* [ethash] replace mem::uninitialized with MaybeUninit

* [ethash] replace another occurence of mem::uninitialized

* [ethash] remove last mem::uninitialized

* [ethash] clean up benches

* [ethash] update outdated comment

* [ethash] compile error on big endian targets

* [ethash] extract 32 into a constant

* [ethash] rename the constant to KECCAK_LEN

* [ethash] bench quick_get_difficulty

* [ethash] remove MaybeUninit completely

* [ethash] replace ptr::copy_nonoverlapping with copy_from_slice

* [ethash] s/header_len/hash_len

* [ethash] remove duplication in bench

* [ethash] add a config for basic benches

* [ethash] fix a typo in bench fn name

* [ethash] remove needless cast
2019-07-12 10:04:41 +02:00

443 lines
14 KiB
Rust

// Copyright 2015-2019 Parity Technologies (UK) Ltd.
// This file is part of Parity Ethereum.
// Parity Ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Parity Ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Parity Ethereum. If not, see <http://www.gnu.org/licenses/>.
//! Ethash implementation
//! See https://github.com/ethereum/wiki/wiki/Ethash
// TODO: fix endianess for big endian
use keccak::{keccak_512, keccak_256, H256};
use cache::{NodeCache, NodeCacheBuilder};
use progpow::{CDag, generate_cdag, progpow, keccak_f800_short, keccak_f800_long};
use seed_compute::SeedHashCompute;
use shared::*;
use std::io;
use std::mem;
use std::path::Path;
const MIX_WORDS: usize = ETHASH_MIX_BYTES / 4;
const MIX_NODES: usize = MIX_WORDS / NODE_WORDS;
pub const FNV_PRIME: u32 = 0x01000193;
/// Computation result
pub struct ProofOfWork {
/// Difficulty boundary
pub value: H256,
/// Mix
pub mix_hash: H256,
}
enum Algorithm {
Hashimoto,
Progpow(Box<CDag>),
}
pub struct Light {
block_number: u64,
cache: NodeCache,
algorithm: Algorithm,
}
/// Light cache structure
impl Light {
pub fn new_with_builder(
builder: &NodeCacheBuilder,
cache_dir: &Path,
block_number: u64,
progpow_transition: u64,
) -> Self {
let cache = builder.new_cache(cache_dir.to_path_buf(), block_number);
let algorithm = if block_number >= progpow_transition {
Algorithm::Progpow(Box::new(generate_cdag(cache.as_ref())))
} else {
Algorithm::Hashimoto
};
Light { block_number, cache, algorithm }
}
/// Calculate the light boundary data
/// `header_hash` - The header hash to pack into the mix
/// `nonce` - The nonce to pack into the mix
pub fn compute(&self, header_hash: &H256, nonce: u64, block_number: u64) -> ProofOfWork {
match self.algorithm {
Algorithm::Progpow(ref c_dag) => {
let (value, mix_hash) = progpow(
*header_hash,
nonce,
block_number,
self.cache.as_ref(),
c_dag,
);
ProofOfWork { value, mix_hash }
},
Algorithm::Hashimoto => light_compute(self, header_hash, nonce),
}
}
pub fn from_file_with_builder(
builder: &NodeCacheBuilder,
cache_dir: &Path,
block_number: u64,
progpow_transition: u64,
) -> io::Result<Self> {
let cache = builder.from_file(cache_dir.to_path_buf(), block_number)?;
let algorithm = if block_number >= progpow_transition {
Algorithm::Progpow(Box::new(generate_cdag(cache.as_ref())))
} else {
Algorithm::Hashimoto
};
Ok(Light { block_number, cache, algorithm })
}
pub fn to_file(&mut self) -> io::Result<&Path> {
self.cache.flush()?;
Ok(self.cache.cache_path())
}
}
pub fn slow_hash_block_number(block_number: u64) -> H256 {
SeedHashCompute::resume_compute_seedhash([0u8; 32], 0, block_number / ETHASH_EPOCH_LENGTH)
}
fn fnv_hash(x: u32, y: u32) -> u32 {
return x.wrapping_mul(FNV_PRIME) ^ y;
}
/// Difficulty quick check for POW preverification
///
/// `header_hash` The hash of the header
/// `nonce` The block's nonce
/// `mix_hash` The mix digest hash
/// Boundary recovered from mix hash
pub fn quick_get_difficulty(header_hash: &H256, nonce: u64, mix_hash: &H256, progpow: bool) -> H256 {
unsafe {
if progpow {
let seed = keccak_f800_short(*header_hash, nonce, [0u32; 8]);
keccak_f800_long(*header_hash, seed, mem::transmute(*mix_hash))
} else {
let mut buf = [0u8; 64 + 32];
let hash_len = header_hash.len();
buf[..hash_len].copy_from_slice(header_hash);
buf[hash_len..hash_len + mem::size_of::<u64>()].copy_from_slice(&nonce.to_ne_bytes());
keccak_512::unchecked(buf.as_mut_ptr(), 64, buf.as_ptr(), 40);
buf[64..].copy_from_slice(mix_hash);
let mut hash = [0u8; 32];
keccak_256::unchecked(hash.as_mut_ptr(), hash.len(), buf.as_ptr(), buf.len());
hash
}
}
}
/// Calculate the light client data
/// `light` - The light client handler
/// `header_hash` - The header hash to pack into the mix
/// `nonce` - The nonce to pack into the mix
pub fn light_compute(light: &Light, header_hash: &H256, nonce: u64) -> ProofOfWork {
let full_size = get_data_size(light.block_number);
hash_compute(light, full_size, header_hash, nonce)
}
fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64) -> ProofOfWork {
macro_rules! make_const_array {
($n:expr, $value:expr) => {{
// We use explicit lifetimes to ensure that val's borrow is invalidated until the
// transmuted val dies.
unsafe fn make_const_array<T, U>(val: &mut [T]) -> &mut [U; $n] {
use ::std::mem;
debug_assert_eq!(val.len() * mem::size_of::<T>(), $n * mem::size_of::<U>());
&mut *(val.as_mut_ptr() as *mut [U; $n])
}
make_const_array($value)
}}
}
#[repr(C)]
struct MixBuf {
half_mix: Node,
compress_bytes: [u8; MIX_WORDS],
};
if full_size % MIX_WORDS != 0 {
panic!("Unaligned full size");
}
// You may be asking yourself: what in the name of Crypto Jesus is going on here? So: we need
// `half_mix` and `compress_bytes` in a single array later down in the code (we hash them
// together to create `value`) so that we can hash the full array. However, we do a bunch of
// reading and writing to these variables first. We originally allocated two arrays and then
// stuck them together with `ptr::copy_nonoverlapping` at the end, but this method is
// _significantly_ faster - by my benchmarks, a consistent 3-5%. This is the most ridiculous
// optimization I have ever done and I am so sorry. I can only chalk it up to cache locality
// improvements, since I can't imagine that 3-5% of our runtime is taken up by catting two
// arrays together.
let mut buf: MixBuf = MixBuf {
half_mix: unsafe {
// Pack `header_hash` and `nonce` together
let mut out = [0u8; NODE_BYTES];
let hash_len = header_hash.len();
out[..hash_len].copy_from_slice(header_hash);
out[hash_len..hash_len + mem::size_of::<u64>()].copy_from_slice(&nonce.to_ne_bytes());
// compute keccak-512 hash and replicate across mix
keccak_512::unchecked(
out.as_mut_ptr(),
NODE_BYTES,
out.as_ptr(),
header_hash.len() + mem::size_of::<u64>(),
);
Node { bytes: out }
},
compress_bytes: [0u8; MIX_WORDS],
};
let mut mix: [_; MIX_NODES] = [buf.half_mix.clone(), buf.half_mix.clone()];
let page_size = 4 * MIX_WORDS;
let num_full_pages = (full_size / page_size) as u32;
// deref once for better performance
let cache: &[Node] = light.cache.as_ref();
let first_val = buf.half_mix.as_words()[0];
debug_assert_eq!(MIX_NODES, 2);
debug_assert_eq!(NODE_WORDS, 16);
for i in 0..ETHASH_ACCESSES as u32 {
let index = {
// This is trivially safe, but does not work on big-endian. The safety of this is
// asserted in debug builds (see the definition of `make_const_array!`).
let mix_words: &mut [u32; MIX_WORDS] =
unsafe { make_const_array!(MIX_WORDS, &mut mix) };
fnv_hash(first_val ^ i, mix_words[i as usize % MIX_WORDS]) % num_full_pages
};
unroll! {
// MIX_NODES
for n in 0..2 {
let tmp_node = calculate_dag_item(
index * MIX_NODES as u32 + n as u32,
cache,
);
unroll! {
// NODE_WORDS
for w in 0..16 {
mix[n].as_words_mut()[w] =
fnv_hash(
mix[n].as_words()[w],
tmp_node.as_words()[w],
);
}
}
}
}
}
let mix_words: [u32; MIX_WORDS] = unsafe { mem::transmute(mix) };
{
// We iterate precisely `compress.len()` times and set each index,
// leaving the array fully initialized. THIS ONLY WORKS ON LITTLE-ENDIAN MACHINES.
// See a future PR to make this and the rest of the code work correctly on
// big-endian arches like mips.
let compress: &mut [u32; MIX_WORDS / 4] =
unsafe { make_const_array!(MIX_WORDS / 4, &mut buf.compress_bytes) };
#[cfg(target_endian = "big")]
{
compile_error!("parity-ethereum currently only supports little-endian targets");
}
// Compress mix
debug_assert_eq!(MIX_WORDS / 4, 8);
unroll! {
for i in 0..8 {
let w = i * 4;
let mut reduction = mix_words[w + 0];
reduction = reduction.wrapping_mul(FNV_PRIME) ^ mix_words[w + 1];
reduction = reduction.wrapping_mul(FNV_PRIME) ^ mix_words[w + 2];
reduction = reduction.wrapping_mul(FNV_PRIME) ^ mix_words[w + 3];
compress[i] = reduction;
}
}
}
let mix_hash = buf.compress_bytes;
let value: H256 = {
// We can interpret the buffer as an array of `u8`s, since it's `repr(C)`.
let read_ptr: *const u8 = &buf as *const MixBuf as *const u8;
// We overwrite the second half since `keccak_256` has an internal buffer and so allows
// overlapping arrays as input.
let write_ptr: *mut u8 = &mut buf.compress_bytes as *mut [u8; 32] as *mut u8;
unsafe {
keccak_256::unchecked(
write_ptr,
buf.compress_bytes.len(),
read_ptr,
buf.half_mix.bytes.len() + buf.compress_bytes.len(),
);
}
buf.compress_bytes
};
ProofOfWork { mix_hash: mix_hash, value: value }
}
// TODO: Use the `simd` crate
pub fn calculate_dag_item(node_index: u32, cache: &[Node]) -> Node {
let num_parent_nodes = cache.len();
let mut ret = cache[node_index as usize % num_parent_nodes].clone();
ret.as_words_mut()[0] ^= node_index;
keccak_512::inplace(ret.as_bytes_mut());
debug_assert_eq!(NODE_WORDS, 16);
for i in 0..ETHASH_DATASET_PARENTS as u32 {
let parent_index = fnv_hash(node_index ^ i, ret.as_words()[i as usize % NODE_WORDS]) %
num_parent_nodes as u32;
let parent = &cache[parent_index as usize];
unroll! {
for w in 0..16 {
ret.as_words_mut()[w] = fnv_hash(ret.as_words()[w], parent.as_words()[w]);
}
}
}
keccak_512::inplace(ret.as_bytes_mut());
ret
}
#[cfg(test)]
mod test {
use super::*;
use std::fs;
use tempdir::TempDir;
#[test]
fn test_get_cache_size() {
// https://github.com/ethereum/wiki/wiki/Ethash/ef6b93f9596746a088ea95d01ca2778be43ae68f#data-sizes
assert_eq!(16776896usize, get_cache_size(0));
assert_eq!(16776896usize, get_cache_size(1));
assert_eq!(16776896usize, get_cache_size(ETHASH_EPOCH_LENGTH - 1));
assert_eq!(16907456usize, get_cache_size(ETHASH_EPOCH_LENGTH));
assert_eq!(16907456usize, get_cache_size(ETHASH_EPOCH_LENGTH + 1));
assert_eq!(284950208usize, get_cache_size(2046 * ETHASH_EPOCH_LENGTH));
assert_eq!(285081536usize, get_cache_size(2047 * ETHASH_EPOCH_LENGTH));
assert_eq!(285081536usize, get_cache_size(2048 * ETHASH_EPOCH_LENGTH - 1));
}
#[test]
fn test_get_data_size() {
// https://github.com/ethereum/wiki/wiki/Ethash/ef6b93f9596746a088ea95d01ca2778be43ae68f#data-sizes
assert_eq!(1073739904usize, get_data_size(0));
assert_eq!(1073739904usize, get_data_size(1));
assert_eq!(1073739904usize, get_data_size(ETHASH_EPOCH_LENGTH - 1));
assert_eq!(1082130304usize, get_data_size(ETHASH_EPOCH_LENGTH));
assert_eq!(1082130304usize, get_data_size(ETHASH_EPOCH_LENGTH + 1));
assert_eq!(18236833408usize, get_data_size(2046 * ETHASH_EPOCH_LENGTH));
assert_eq!(18245220736usize, get_data_size(2047 * ETHASH_EPOCH_LENGTH));
}
#[test]
fn test_difficulty_test() {
let hash = [
0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe, 0xe4, 0x0a, 0xb3,
0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f, 0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94,
0x05, 0x52, 0x7d, 0x72,
];
let mix_hash = [
0x1f, 0xff, 0x04, 0xce, 0xc9, 0x41, 0x73, 0xfd, 0x59, 0x1e, 0x3d, 0x89, 0x60, 0xce,
0x6b, 0xdf, 0x8b, 0x19, 0x71, 0x04, 0x8c, 0x71, 0xff, 0x93, 0x7b, 0xb2, 0xd3, 0x2a,
0x64, 0x31, 0xab, 0x6d,
];
let nonce = 0xd7b3ac70a301a249;
let boundary_good = [
0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3e, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2,
0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a,
0xe9, 0x7e, 0x53, 0x84,
];
assert_eq!(quick_get_difficulty(&hash, nonce, &mix_hash, false)[..], boundary_good[..]);
let boundary_bad = [
0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3a, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2,
0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a,
0xe9, 0x7e, 0x53, 0x84,
];
assert!(quick_get_difficulty(&hash, nonce, &mix_hash, false)[..] != boundary_bad[..]);
}
#[test]
fn test_light_compute() {
let hash = [
0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe, 0xe4, 0x0a, 0xb3,
0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f, 0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94,
0x05, 0x52, 0x7d, 0x72,
];
let mix_hash = [
0x1f, 0xff, 0x04, 0xce, 0xc9, 0x41, 0x73, 0xfd, 0x59, 0x1e, 0x3d, 0x89, 0x60, 0xce,
0x6b, 0xdf, 0x8b, 0x19, 0x71, 0x04, 0x8c, 0x71, 0xff, 0x93, 0x7b, 0xb2, 0xd3, 0x2a,
0x64, 0x31, 0xab, 0x6d,
];
let boundary = [
0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3e, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2,
0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a,
0xe9, 0x7e, 0x53, 0x84,
];
let nonce = 0xd7b3ac70a301a249;
let tempdir = TempDir::new("").unwrap();
// difficulty = 0x085657254bd9u64;
let light = NodeCacheBuilder::new(None, u64::max_value()).light(tempdir.path(), 486382);
let result = light_compute(&light, &hash, nonce);
assert_eq!(result.mix_hash[..], mix_hash[..]);
assert_eq!(result.value[..], boundary[..]);
}
#[test]
fn test_drop_old_data() {
let tempdir = TempDir::new("").unwrap();
let builder = NodeCacheBuilder::new(None, u64::max_value());
let first = builder.light(tempdir.path(), 0).to_file().unwrap().to_owned();
let second = builder.light(tempdir.path(), ETHASH_EPOCH_LENGTH).to_file().unwrap().to_owned();
assert!(fs::metadata(&first).is_ok());
let _ = builder.light(tempdir.path(), ETHASH_EPOCH_LENGTH * 2).to_file();
assert!(fs::metadata(&first).is_err());
assert!(fs::metadata(&second).is_ok());
let _ = builder.light(tempdir.path(), ETHASH_EPOCH_LENGTH * 3).to_file();
assert!(fs::metadata(&second).is_err());
}
}