331 lines
12 KiB
Rust
331 lines
12 KiB
Rust
//! Ethash implementation
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//! See https://github.com/ethereum/wiki/wiki/Ethash
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// TODO: fix endianess for big endian
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use std::mem;
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use std::ptr;
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use sizes::{CACHE_SIZES, DAG_SIZES};
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use sha3;
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use std::slice;
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use std::path::PathBuf;
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use std::io::{Read, Write, self};
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use std::fs::{self, File};
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pub const ETHASH_EPOCH_LENGTH: u64 = 30000;
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pub const ETHASH_CACHE_ROUNDS: usize = 3;
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pub const ETHASH_MIX_BYTES: usize = 128;
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pub const ETHASH_ACCESSES:usize = 64;
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pub const ETHASH_DATASET_PARENTS:u32 = 256;
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const NODE_WORDS: usize = 64 / 4;
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const NODE_BYTES: usize = 64;
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const MIX_WORDS: usize = ETHASH_MIX_BYTES / 4;
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const MIX_NODES: usize = MIX_WORDS / NODE_WORDS;
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const FNV_PRIME: u32 = 0x01000193;
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/// Computation result
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pub struct ProofOfWork {
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/// Difficulty boundary
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pub value: H256,
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/// Mix
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pub mix_hash: H256
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}
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struct Node {
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bytes: [u8; NODE_BYTES],
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}
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impl Default for Node {
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fn default() -> Self {
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Node { bytes: [0u8; NODE_BYTES] }
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}
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}
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impl Clone for Node {
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fn clone(&self) -> Self {
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Node { bytes: *&self.bytes }
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}
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}
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impl Node {
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#[inline]
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fn as_words(&self) -> &[u32; NODE_WORDS] {
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unsafe { mem::transmute(&self.bytes) }
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}
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#[inline]
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fn as_words_mut(&mut self) -> &mut [u32; NODE_WORDS] {
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unsafe { mem::transmute(&mut self.bytes) }
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}
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}
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pub type H256 = [u8; 32];
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pub struct Light {
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block_number: u64,
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cache: Vec<Node>,
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}
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/// Light cache structur
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impl Light {
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/// Create a new light cache for a given block number
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pub fn new(block_number: u64) -> Light {
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light_new(block_number)
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}
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/// Calculate the light boundary data
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/// `header_hash` - The header hash to pack into the mix
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/// `nonce` - The nonce to pack into the mix
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pub fn compute(&self, header_hash: &H256, nonce: u64) -> ProofOfWork {
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light_compute(self, header_hash, nonce)
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}
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pub fn file_path(block_number: u64) -> PathBuf {
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let mut home = ::std::env::home_dir().unwrap();
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home.push(".ethash");
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home.push("light");
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let seed_hash = get_seedhash(block_number);
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home.push(to_hex(&seed_hash));
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home
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}
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pub fn from_file(block_number: u64) -> io::Result<Light> {
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let path = Light::file_path(block_number);
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let mut file = try!(File::open(path));
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let cache_size = get_cache_size(block_number);
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if try!(file.metadata()).len() != cache_size as u64 {
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return Err(io::Error::new(io::ErrorKind::Other, "Cache file size mismatch"));
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}
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let num_nodes = cache_size / NODE_BYTES;
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let mut nodes: Vec<Node> = Vec::new();
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nodes.resize(num_nodes, unsafe { mem::uninitialized() });
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let buf = unsafe { slice::from_raw_parts_mut(nodes.as_mut_ptr() as *mut u8, cache_size) };
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try!(file.read_exact(buf));
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Ok(Light {
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cache: nodes,
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block_number: block_number,
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})
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}
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pub fn to_file(&self) -> io::Result<()> {
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let path = Light::file_path(self.block_number);
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try!(fs::create_dir_all(path.parent().unwrap()));
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let mut file = try!(File::create(path));
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let cache_size = self.cache.len() * NODE_BYTES;
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let buf = unsafe { slice::from_raw_parts(self.cache.as_ptr() as *const u8, cache_size) };
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try!(file.write(buf));
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Ok(())
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}
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}
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#[inline]
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fn fnv_hash(x: u32, y: u32) -> u32 {
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return x.wrapping_mul(FNV_PRIME) ^ y;
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}
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#[inline]
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fn sha3_512(input: &[u8], output: &mut [u8]) {
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unsafe { sha3::sha3_512(output.as_mut_ptr(), output.len(), input.as_ptr(), input.len()) };
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}
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#[inline]
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fn get_cache_size(block_number: u64) -> usize {
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assert!(block_number / ETHASH_EPOCH_LENGTH < 2048);
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return CACHE_SIZES[(block_number / ETHASH_EPOCH_LENGTH) as usize] as usize;
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}
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#[inline]
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fn get_data_size(block_number: u64) -> usize {
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assert!(block_number / ETHASH_EPOCH_LENGTH < 2048);
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return DAG_SIZES[(block_number / ETHASH_EPOCH_LENGTH) as usize] as usize;
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}
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#[inline]
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fn get_seedhash(block_number: u64) -> H256 {
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let epochs = block_number / ETHASH_EPOCH_LENGTH;
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let mut ret: H256 = [0u8; 32];
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for _ in 0..epochs {
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unsafe { sha3::sha3_256(ret[..].as_mut_ptr(), 32, ret[..].as_ptr(), 32) };
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}
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ret
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}
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/// Difficulty quick check for POW preverification
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///
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/// `header_hash` The hash of the header
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/// `nonce` The block's nonce
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/// `mix_hash` The mix digest hash
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/// Boundary recovered from mix hash
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pub fn quick_get_difficulty(header_hash: &H256, nonce: u64, mix_hash: &H256) -> H256 {
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let mut buf = [0u8; 64 + 32];
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unsafe { ptr::copy_nonoverlapping(header_hash.as_ptr(), buf.as_mut_ptr(), 32) };
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unsafe { ptr::copy_nonoverlapping(mem::transmute(&nonce), buf[32..].as_mut_ptr(), 8) };
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unsafe { sha3::sha3_512(buf.as_mut_ptr(), 64, buf.as_ptr(), 40) };
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unsafe { ptr::copy_nonoverlapping(mix_hash.as_ptr(), buf[64..].as_mut_ptr(), 32) };
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let mut hash = [0u8; 32];
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unsafe { sha3::sha3_256(hash.as_mut_ptr(), hash.len(), buf.as_ptr(), buf.len()) };
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hash.as_mut_ptr();
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hash
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}
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/// Calculate the light client data
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/// `light` - The light client handler
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/// `header_hash` - The header hash to pack into the mix
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/// `nonce` - The nonce to pack into the mix
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pub fn light_compute(light: &Light, header_hash: &H256, nonce: u64) -> ProofOfWork {
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let full_size = get_data_size(light.block_number);
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hash_compute(light, full_size, header_hash, nonce)
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}
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fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64) -> ProofOfWork {
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if full_size % MIX_WORDS != 0 {
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panic!("Unaligned full size");
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}
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// pack hash and nonce together into first 40 bytes of s_mix
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let mut s_mix: [Node; MIX_NODES + 1] = [ Node::default(), Node::default(), Node::default() ];
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unsafe { ptr::copy_nonoverlapping(header_hash.as_ptr(), s_mix.get_unchecked_mut(0).bytes.as_mut_ptr(), 32) };
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unsafe { ptr::copy_nonoverlapping(mem::transmute(&nonce), s_mix.get_unchecked_mut(0).bytes[32..].as_mut_ptr(), 8) };
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// compute sha3-512 hash and replicate across mix
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unsafe {
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sha3::sha3_512(s_mix.get_unchecked_mut(0).bytes.as_mut_ptr(), NODE_BYTES, s_mix.get_unchecked(0).bytes.as_ptr(), 40);
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let (f_mix, mut mix) = s_mix.split_at_mut(1);
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for w in 0..MIX_WORDS {
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*mix.get_unchecked_mut(0).as_words_mut().get_unchecked_mut(w) = *f_mix.get_unchecked(0).as_words().get_unchecked(w % NODE_WORDS);
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}
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let page_size = 4 * MIX_WORDS;
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let num_full_pages = (full_size / page_size) as u32;
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for i in 0..(ETHASH_ACCESSES as u32) {
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let index = fnv_hash(f_mix.get_unchecked(0).as_words().get_unchecked(0) ^ i, *mix.get_unchecked(0).as_words().get_unchecked((i as usize) % MIX_WORDS)) % num_full_pages;
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for n in 0..MIX_NODES {
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let tmp_node = calculate_dag_item(index * MIX_NODES as u32 + n as u32, light);
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for w in 0..NODE_WORDS {
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*mix.get_unchecked_mut(n).as_words_mut().get_unchecked_mut(w) = fnv_hash(*mix.get_unchecked(n).as_words().get_unchecked(w), *tmp_node.as_words().get_unchecked(w));
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}
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}
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}
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// compress mix
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for i in 0..(MIX_WORDS / 4) {
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let w = i * 4;
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let mut reduction = *mix.get_unchecked(0).as_words().get_unchecked(w + 0);
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reduction = reduction.wrapping_mul(FNV_PRIME) ^ *mix.get_unchecked(0).as_words().get_unchecked(w + 1);
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reduction = reduction.wrapping_mul(FNV_PRIME) ^ *mix.get_unchecked(0).as_words().get_unchecked(w + 2);
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reduction = reduction.wrapping_mul(FNV_PRIME) ^ *mix.get_unchecked(0).as_words().get_unchecked(w + 3);
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*mix.get_unchecked_mut(0).as_words_mut().get_unchecked_mut(i) = reduction;
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}
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let mut mix_hash = [0u8; 32];
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let mut buf = [0u8; 32 + 64];
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ptr::copy_nonoverlapping(f_mix.get_unchecked_mut(0).bytes.as_ptr(), buf.as_mut_ptr(), 64);
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ptr::copy_nonoverlapping(mix.get_unchecked_mut(0).bytes.as_ptr(), buf[64..].as_mut_ptr(), 32);
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ptr::copy_nonoverlapping(mix.get_unchecked_mut(0).bytes.as_ptr(), mix_hash.as_mut_ptr(), 32);
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let mut value: H256 = [0u8; 32];
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sha3::sha3_256(value.as_mut_ptr(), value.len(), buf.as_ptr(), buf.len());
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ProofOfWork {
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mix_hash: mix_hash,
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value: value,
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}
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}
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}
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fn calculate_dag_item(node_index: u32, light: &Light) -> Node {
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unsafe {
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let num_parent_nodes = light.cache.len();
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let cache_nodes = &light.cache;
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let init = cache_nodes.get_unchecked(node_index as usize % num_parent_nodes);
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let mut ret = init.clone();
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*ret.as_words_mut().get_unchecked_mut(0) ^= node_index;
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sha3::sha3_512(ret.bytes.as_mut_ptr(), ret.bytes.len(), ret.bytes.as_ptr(), ret.bytes.len());
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for i in 0..ETHASH_DATASET_PARENTS {
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let parent_index = fnv_hash(node_index ^ i, *ret.as_words().get_unchecked(i as usize % NODE_WORDS)) % num_parent_nodes as u32;
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let parent = cache_nodes.get_unchecked(parent_index as usize);
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for w in 0..NODE_WORDS {
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*ret.as_words_mut().get_unchecked_mut(w) = fnv_hash(*ret.as_words().get_unchecked(w), *parent.as_words().get_unchecked(w));
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}
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}
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sha3::sha3_512(ret.bytes.as_mut_ptr(), ret.bytes.len(), ret.bytes.as_ptr(), ret.bytes.len());
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ret
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}
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}
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fn light_new(block_number: u64) -> Light {
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let seedhash = get_seedhash(block_number);
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let cache_size = get_cache_size(block_number);
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if cache_size % NODE_BYTES != 0 {
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panic!("Unaligned cache size");
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}
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let num_nodes = cache_size / NODE_BYTES;
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let mut nodes = Vec::with_capacity(num_nodes);
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nodes.resize(num_nodes, Node::default());
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unsafe {
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sha3_512(&seedhash[0..32], &mut nodes.get_unchecked_mut(0).bytes);
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for i in 1..num_nodes {
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sha3::sha3_512(nodes.get_unchecked_mut(i).bytes.as_mut_ptr(), NODE_BYTES, nodes.get_unchecked(i - 1).bytes.as_ptr(), NODE_BYTES);
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}
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for _ in 0..ETHASH_CACHE_ROUNDS {
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for i in 0..num_nodes {
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let idx = *nodes.get_unchecked_mut(i).as_words().get_unchecked(0) as usize % num_nodes;
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let mut data = nodes.get_unchecked((num_nodes - 1 + i) % num_nodes).clone();
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for w in 0..NODE_WORDS {
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*data.as_words_mut().get_unchecked_mut(w) ^= *nodes.get_unchecked(idx).as_words().get_unchecked(w) ;
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}
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sha3_512(&data.bytes, &mut nodes.get_unchecked_mut(i).bytes);
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}
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}
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}
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Light {
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cache: nodes,
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block_number: block_number,
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}
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}
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static CHARS: &'static[u8] = b"0123456789abcdef";
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fn to_hex(bytes: &[u8]) -> String {
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let mut v = Vec::with_capacity(bytes.len() * 2);
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for &byte in bytes.iter() {
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v.push(CHARS[(byte >> 4) as usize]);
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v.push(CHARS[(byte & 0xf) as usize]);
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}
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unsafe {
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String::from_utf8_unchecked(v)
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}
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}
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#[test]
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fn test_difficulty_test() {
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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];
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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 ];
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let nonce = 0xd7b3ac70a301a249;
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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];
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assert_eq!(quick_get_difficulty(&hash, nonce, &mix_hash)[..], boundary_good[..]);
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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];
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assert!(quick_get_difficulty(&hash, nonce, &mix_hash)[..] != boundary_bad[..]);
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}
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#[test]
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fn test_light_compute() {
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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];
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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 ];
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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];
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let nonce = 0xd7b3ac70a301a249;
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// difficulty = 0x085657254bd9u64;
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let light = Light::new(486382);
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let result = light_compute(&light, &hash, nonce);
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assert_eq!(result.mix_hash[..], mix_hash[..]);
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assert_eq!(result.value[..], boundary[..]);
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}
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