Disable mixhash verification for now.

Cargo.toml

@@ -4,6 +4,7 @@ panic = 'unwind'
 [workspace]
 members = [
 	"core/cli",
+	"core/ethash",
     "core/merkle-mountain-range",
     "core/fly-client",
     "core/sr-eth-primitives",

core/ethash/Cargo.toml

@@ -0,0 +1,29 @@
+[package]
+name = "ethash"
+description = "An Apache-licensed Ethash implementation."
+version = "0.4.0"
+authors = ["Wei Tang <hi@that.world>"]
+license = "Apache-2.0"
+edition = "2018"
+
+[dependencies]
+byteorder = { version = "1", default-features = false }
+rlp = { version = "0.4", default-features = false }
+sha3 = { version = "0.8", default-features = false }
+
+ethereum-types = { git = "https://github.com/darwinia-network/parity-common.git", default-features = false }
+primitive-types = { git = "https://github.com/darwinia-network/parity-common.git", default-features = false, features = ["rlp"] }
+
+[dev-dependencies]
+hex-literal = "0.2.1"
+
+[features]
+default = ["std"]
+std = [
+  "byteorder/std",
+  "rlp/std",
+  "sha3/std",
+
+  "ethereum-types/std",
+  "primitive-types/std",
+]

core/ethash/src/dag.rs

@@ -0,0 +1,52 @@
+use alloc::vec::Vec;
+use core::marker::PhantomData;
+use ethereum_types::{H256, H64, U256};
+
+pub trait Patch {
+	fn epoch_length() -> U256;
+}
+
+pub struct EthereumPatch;
+impl Patch for EthereumPatch {
+	fn epoch_length() -> U256 {
+		U256::from(30000)
+	}
+}
+
+pub struct LightDAG<P: Patch> {
+	epoch: usize,
+	cache: Vec<u8>,
+	#[allow(dead_code)]
+	cache_size: usize,
+	full_size: usize,
+	_marker: PhantomData<P>,
+}
+
+impl<P: Patch> LightDAG<P> {
+	pub fn new(number: U256) -> Self {
+		let epoch = (number / P::epoch_length()).as_usize();
+		let cache_size = crate::get_cache_size(epoch);
+		let full_size = crate::get_full_size(epoch);
+		let seed = crate::get_seedhash(epoch);
+
+		let mut cache: Vec<u8> = Vec::with_capacity(cache_size);
+		cache.resize(cache_size, 0);
+		crate::make_cache(&mut cache, seed);
+
+		Self {
+			cache,
+			cache_size,
+			full_size,
+			epoch,
+			_marker: PhantomData,
+		}
+	}
+
+	pub fn hashimoto(&self, hash: H256, nonce: H64) -> (H256, H256) {
+		crate::hashimoto_light(hash, nonce, self.full_size, &self.cache)
+	}
+
+	pub fn is_valid_for(&self, number: U256) -> bool {
+		(number / P::epoch_length()).as_usize() == self.epoch
+	}
+}