Use ethash for verification

2016-01-17 12:00:34 +01:00
parent d07934ffee
commit e39e7491b8
9 changed files with 1183 additions and 7 deletions
--- a/ethash/src/compute.rs
+++ b/ethash/src/compute.rs
@@ -0,0 +1,294 @@
+//! Ethash implementation
+//! See https://github.com/ethereum/wiki/wiki/Ethash
+
+// TODO: fix endianess for big endian
+
+use std::mem;
+use std::ptr;
+use sizes::{CACHE_SIZES, DAG_SIZES};
+use tiny_keccak::Keccak;
+
+pub const ETHASH_EPOCH_LENGTH: u64 = 30000;
+pub const ETHASH_CACHE_ROUNDS: usize = 3;
+pub const ETHASH_MIX_BYTES: usize = 128;
+pub const ETHASH_ACCESSES:usize =  64;
+pub const ETHASH_DATASET_PARENTS:u32 = 256;
+
+const NODE_WORDS: usize = 64 / 4;
+const NODE_BYTES: usize = 64;
+const MIX_WORDS: usize = ETHASH_MIX_BYTES / 4;
+const MIX_NODES: usize = MIX_WORDS / NODE_WORDS;
+const FNV_PRIME: u32 =  0x01000193;
+
+/// Computation result
+pub struct ProofOfWork {
+	/// Difficulty boundary
+	pub value: H256,
+	/// Mix
+	pub mix_hash: H256
+}
+
+struct Node {
+	bytes: [u8; NODE_BYTES],
+}
+
+impl Default for Node {
+	fn default() -> Self { 
+		Node { bytes: [0u8; NODE_BYTES] }
+	}
+}
+
+impl Clone for Node {
+	fn clone(&self) -> Self {
+		Node { bytes: *&self.bytes }
+	}
+}
+
+impl Node {
+	#[inline]
+	fn as_words(&self) -> &[u32; NODE_WORDS] {
+		unsafe { mem::transmute(&self.bytes) }
+	}
+
+	#[inline]
+	fn as_words_mut(&mut self) -> &mut [u32; NODE_WORDS] {
+		unsafe { mem::transmute(&mut self.bytes) }
+	}
+}
+
+pub type H256 = [u8; 32];
+
+pub struct Light {
+	block_number: u64,
+	cache: Vec<Node>,
+}
+
+/// Light cache structur
+impl Light {
+	/// Create a new light cache for a given block number
+	pub fn new(block_number: u64) -> Light {
+		light_new(block_number)
+	}
+
+	/// 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) -> ProofOfWork {
+		light_compute(self, header_hash, nonce)
+	}
+}
+
+#[inline]
+fn fnv_hash(x: u32, y: u32) -> u32 {
+	return x.wrapping_mul(FNV_PRIME) ^ y;
+}
+
+#[inline]
+fn sha3_512(input: &[u8], output: &mut [u8]) {
+		let mut sha3 = Keccak::new_keccak512();
+		sha3.update(input);
+		sha3.finalize(output);
+}
+
+#[inline]
+fn get_cache_size(block_number: u64) -> usize {
+	assert!(block_number / ETHASH_EPOCH_LENGTH < 2048);
+	return CACHE_SIZES[(block_number / ETHASH_EPOCH_LENGTH) as usize] as usize;
+}
+
+#[inline]
+fn get_data_size(block_number: u64) -> usize {
+	assert!(block_number / ETHASH_EPOCH_LENGTH < 2048);
+	return DAG_SIZES[(block_number / ETHASH_EPOCH_LENGTH) as usize] as usize;
+}
+
+#[inline]
+fn get_seedhash(block_number: u64) -> H256 {
+	let epochs = block_number / ETHASH_EPOCH_LENGTH;
+	let mut ret: H256 = [0u8; 32];
+	for _ in 0..epochs {
+		let mut sha3 = Keccak::new_keccak256();
+		sha3.update(&ret);
+		sha3.finalize(&mut ret);
+	}
+	ret
+}
+
+/// 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) -> H256 {
+	let mut buf = [0u8; 64 + 32];
+	unsafe { ptr::copy_nonoverlapping(header_hash.as_ptr(), buf.as_mut_ptr(), 32) };
+	unsafe { ptr::copy_nonoverlapping(mem::transmute(&nonce), buf[32..].as_mut_ptr(), 8) };
+
+	let mut sha3 = Keccak::new_keccak512();
+	sha3.update(&buf[0..40]);
+	sha3.finalize(&mut buf);
+	unsafe { ptr::copy_nonoverlapping(mix_hash.as_ptr(), buf[64..].as_mut_ptr(), 32) };
+
+	let mut hash = [0u8; 32];
+	let mut sha3 = Keccak::new_keccak256();
+	sha3.update(&buf);
+	sha3.finalize(&mut hash);
+	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 {
+	if full_size % MIX_WORDS != 0 {
+		panic!("Unaligned full size");
+	}
+	// pack hash and nonce together into first 40 bytes of s_mix
+	let mut s_mix: [Node; MIX_NODES + 1] = [ Node::default(), Node::default(), Node::default() ];
+	unsafe { ptr::copy_nonoverlapping(header_hash.as_ptr(), s_mix.get_unchecked_mut(0).bytes.as_mut_ptr(), 32) };
+	unsafe { ptr::copy_nonoverlapping(mem::transmute(&nonce), s_mix.get_unchecked_mut(0).bytes[32..].as_mut_ptr(), 8) };
+
+	// compute sha3-512 hash and replicate across mix
+	unsafe {
+		let mut sha3 = Keccak::new_keccak512();
+		sha3.update(&s_mix.get_unchecked(0).bytes[0..40]);
+		sha3.finalize(&mut s_mix.get_unchecked_mut(0).bytes);
+
+		let (f_mix, mut mix) = s_mix.split_at_mut(1);
+		for w in 0..MIX_WORDS {
+			*mix.get_unchecked_mut(0).as_words_mut().get_unchecked_mut(w) = *f_mix.get_unchecked(0).as_words().get_unchecked(w % NODE_WORDS);
+		}
+
+		let page_size = 4 * MIX_WORDS;
+		let num_full_pages = (full_size / page_size) as u32;
+
+		for i in 0..(ETHASH_ACCESSES as u32) {
+			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;
+			for n in 0..MIX_NODES {
+				let tmp_node = calculate_dag_item(index * MIX_NODES as u32 + n as u32, light);
+				for w in 0..NODE_WORDS {
+					*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));
+				}
+			}
+		}
+
+		// compress mix
+		for i in 0..(MIX_WORDS / 4) {
+			let w = i * 4;
+			let mut reduction = *mix.get_unchecked(0).as_words().get_unchecked(w + 0);
+			reduction = reduction.wrapping_mul(FNV_PRIME) ^ *mix.get_unchecked(0).as_words().get_unchecked(w + 1);
+			reduction = reduction.wrapping_mul(FNV_PRIME) ^ *mix.get_unchecked(0).as_words().get_unchecked(w + 2);
+			reduction = reduction.wrapping_mul(FNV_PRIME) ^ *mix.get_unchecked(0).as_words().get_unchecked(w + 3);
+			*mix.get_unchecked_mut(0).as_words_mut().get_unchecked_mut(i) = reduction;
+		}
+
+		let mut mix_hash: H256 = [0u8; 32];
+		ptr::copy_nonoverlapping(mix.get_unchecked_mut(0).bytes.as_ptr(), mix_hash.as_mut_ptr(), 32);
+		let mut value: H256 = [0u8; 32];
+
+		let mut sha3 = Keccak::new_keccak256();
+		sha3.update(&f_mix.get_unchecked(0).bytes);
+		sha3.update(&mix_hash);
+		sha3.finalize(&mut value);
+
+		ProofOfWork {
+			mix_hash: mix_hash,
+			value: value,
+		}
+	}
+}
+
+fn calculate_dag_item(node_index: u32, light: &Light) -> Node {
+	unsafe {
+		let num_parent_nodes = light.cache.len();
+		let cache_nodes = &light.cache;
+		let init = cache_nodes.get_unchecked(node_index as usize % num_parent_nodes);
+		let mut ret = init.clone();
+		*ret.as_words_mut().get_unchecked_mut(0) ^= node_index;
+
+		let mut sha3 = Keccak::new_keccak512();
+		sha3.update(&ret.bytes);
+		sha3.finalize(&mut ret.bytes);
+
+		for i in 0..ETHASH_DATASET_PARENTS {
+			let parent_index = fnv_hash(node_index ^ i, *ret.as_words().get_unchecked(i as usize % NODE_WORDS)) % num_parent_nodes as u32;
+			let parent = cache_nodes.get_unchecked(parent_index as usize);
+			for w in 0..NODE_WORDS {
+				*ret.as_words_mut().get_unchecked_mut(w) = fnv_hash(*ret.as_words().get_unchecked(w), *parent.as_words().get_unchecked(w));
+			}
+		}
+
+		let mut sha3 = Keccak::new_keccak512();
+		sha3.update(&ret.bytes);
+		sha3.finalize(&mut ret.bytes);
+		ret
+	}
+}
+
+fn light_new(block_number: u64) -> Light {
+	let seedhash = get_seedhash(block_number);
+	let cache_size = get_cache_size(block_number);
+
+	if cache_size % NODE_BYTES != 0 {
+		panic!("Unaligned cache size");
+	}
+	let num_nodes = cache_size / NODE_BYTES;
+
+	let mut nodes = Vec::with_capacity(num_nodes);
+	nodes.resize(num_nodes, Node::default());
+	unsafe {
+		sha3_512(&seedhash[0..32], &mut nodes.get_unchecked_mut(0).bytes);
+		for i in 1..num_nodes {
+			let mut sha3 = Keccak::new_keccak512();
+			sha3.update(&nodes.get_unchecked_mut(i - 1).bytes);
+			sha3.finalize(&mut nodes.get_unchecked_mut(i).bytes);
+		}
+		
+		for _ in 0..ETHASH_CACHE_ROUNDS {
+			for i in 0..num_nodes {
+				let idx = *nodes.get_unchecked_mut(i).as_words().get_unchecked(0) as usize % num_nodes;
+				let mut data = nodes.get_unchecked((num_nodes - 1 + i) % num_nodes).clone();
+				for w in 0..NODE_WORDS {
+					*data.as_words_mut().get_unchecked_mut(w) ^= *nodes.get_unchecked(idx).as_words().get_unchecked(w) ;
+				}
+				sha3_512(&data.bytes, &mut nodes.get_unchecked_mut(i).bytes);
+			}
+		}
+	}
+
+	Light {
+		cache: nodes,
+		block_number: block_number,
+	}
+}
+
+#[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!(quick_check_difficulty(&hash, nonce, &mix_hash, &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_check_difficulty(&hash, nonce, &mix_hash, &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;
+	// difficulty = 0x085657254bd9u64;
+	let light = Light::new(486382);
+	let result = light_compute(&light, &hash, nonce);
+	assert_eq!(result.mix_hash[..], mix_hash[..]);
+	assert_eq!(result.value[..], boundary[..]);
+}