openethereum/src/ethereum/ethash.rs
2016-01-19 17:02:01 +01:00

247 lines
9.0 KiB
Rust

extern crate ethash;
use self::ethash::{quick_get_difficulty, EthashManager, H256 as EH256};
use common::*;
use block::*;
use spec::*;
use engine::*;
use evm::Schedule;
use evm::Factory;
/// Engine using Ethash proof-of-work consensus algorithm, suitable for Ethereum
/// mainnet chains in the Olympic, Frontier and Homestead eras.
pub struct Ethash {
spec: Spec,
pow: EthashManager,
factory: Factory,
u64_params: RwLock<HashMap<String, u64>>,
u256_params: RwLock<HashMap<String, U256>>,
}
impl Ethash {
/// TODO [arkpar] Please document me
pub fn new_boxed(spec: Spec) -> Box<Engine> {
Box::new(Ethash {
spec: spec,
pow: EthashManager::new(),
// TODO [todr] should this return any specific factory?
factory: Factory::default(),
u64_params: RwLock::new(HashMap::new()),
u256_params: RwLock::new(HashMap::new())
})
}
fn u64_param(&self, name: &str) -> u64 {
*self.u64_params.write().unwrap().entry(name.to_string()).or_insert_with(||
self.spec().engine_params.get(name).map(|a| decode(&a)).unwrap_or(0u64))
}
fn u256_param(&self, name: &str) -> U256 {
*self.u256_params.write().unwrap().entry(name.to_string()).or_insert_with(||
self.spec().engine_params.get(name).map(|a| decode(&a)).unwrap_or(x!(0)))
}
}
impl Engine for Ethash {
fn name(&self) -> &str { "Ethash" }
fn version(&self) -> SemanticVersion { SemanticVersion::new(1, 0, 0) }
// Two fields - mix
fn seal_fields(&self) -> usize { 2 }
// Two empty data items in RLP.
fn seal_rlp(&self) -> Bytes { encode(&H64::new()) }
/// Additional engine-specific information for the user/developer concerning `header`.
fn extra_info(&self, _header: &Header) -> HashMap<String, String> { HashMap::new() }
fn spec(&self) -> &Spec { &self.spec }
fn vm_factory(&self) -> &Factory {
&self.factory
}
fn schedule(&self, env_info: &EnvInfo) -> Schedule {
match env_info.number < self.u64_param("frontierCompatibilityModeLimit") {
true => Schedule::new_frontier(),
_ => Schedule::new_homestead(),
}
}
fn populate_from_parent(&self, header: &mut Header, parent: &Header) {
header.difficulty = self.calculate_difficuty(header, parent);
header.gas_limit = {
let gas_floor_target: U256 = x!(3141562);
let gas_limit = parent.gas_limit;
let bound_divisor = self.u256_param("gasLimitBoundDivisor");
if gas_limit < gas_floor_target {
min(gas_floor_target, gas_limit + gas_limit / bound_divisor - x!(1))
} else {
max(gas_floor_target, gas_limit - gas_limit / bound_divisor + x!(1) + (header.gas_used * x!(6) / x!(5)) / bound_divisor)
}
};
// info!("ethash: populate_from_parent #{}: difficulty={} and gas_limit={}", header.number, header.difficulty, header.gas_limit);
}
/// Apply the block reward on finalisation of the block.
/// This assumes that all uncles are valid uncles (i.e. of at least one generation before the current).
fn on_close_block(&self, block: &mut Block) {
let reward = self.spec().engine_params.get("blockReward").map(|a| decode(&a)).unwrap_or(U256::from(0u64));
let fields = block.fields();
// Bestow block reward
fields.state.add_balance(&fields.header.author, &(reward + reward / U256::from(32) * U256::from(fields.uncles.len())));
// Bestow uncle rewards
let current_number = fields.header.number();
for u in fields.uncles.iter() {
fields.state.add_balance(u.author(), &(reward * U256::from(8 + u.number() - current_number) / U256::from(8)));
}
fields.state.commit();
}
fn verify_block_basic(&self, header: &Header, _block: Option<&[u8]>) -> result::Result<(), Error> {
let min_difficulty = decode(self.spec().engine_params.get("minimumDifficulty").unwrap());
if header.difficulty < min_difficulty {
return Err(From::from(BlockError::InvalidDifficulty(Mismatch { expected: min_difficulty, found: header.difficulty })))
}
let difficulty = Ethash::boundary_to_difficulty(&Ethash::from_ethash(quick_get_difficulty(
&Ethash::to_ethash(header.bare_hash()),
header.nonce(),
&Ethash::to_ethash(header.mix_hash()))));
if difficulty < header.difficulty {
return Err(From::from(BlockError::InvalidEthashDifficulty(Mismatch { expected: header.difficulty, found: difficulty })));
}
Ok(())
}
fn verify_block_unordered(&self, header: &Header, _block: Option<&[u8]>) -> result::Result<(), Error> {
let result = self.pow.compute_light(header.number as u64, &Ethash::to_ethash(header.bare_hash()), header.nonce());
let mix = Ethash::from_ethash(result.mix_hash);
let difficulty = Ethash::boundary_to_difficulty(&Ethash::from_ethash(result.value));
if mix != header.mix_hash() {
return Err(From::from(BlockError::InvalidBlockNonce(Mismatch { expected: mix, found: header.mix_hash() })));
}
if difficulty < header.difficulty {
return Err(From::from(BlockError::InvalidEthashDifficulty(Mismatch { expected: header.difficulty, found: difficulty })));
}
Ok(())
}
fn verify_block_family(&self, header: &Header, parent: &Header, _block: Option<&[u8]>) -> result::Result<(), Error> {
// Check difficulty is correct given the two timestamps.
let expected_difficulty = self.calculate_difficuty(header, parent);
if header.difficulty != expected_difficulty {
return Err(From::from(BlockError::InvalidDifficulty(Mismatch { expected: expected_difficulty, found: header.difficulty })))
}
let gas_limit_divisor = decode(self.spec().engine_params.get("gasLimitBoundDivisor").unwrap());
let min_gas = parent.gas_limit - parent.gas_limit / gas_limit_divisor;
let max_gas = parent.gas_limit + parent.gas_limit / gas_limit_divisor;
if header.gas_limit <= min_gas || header.gas_limit >= max_gas {
return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit })));
}
Ok(())
}
fn verify_transaction_basic(&self, t: &Transaction, header: &Header) -> result::Result<(), Error> {
if header.number() >= self.u64_param("frontierCompatibilityModeLimit") {
try!(t.check_low_s());
}
Ok(())
}
fn verify_transaction(&self, t: &Transaction, _header: &Header) -> Result<(), Error> {
t.sender().map(|_|()) // Perform EC recovery and cache sender
}
}
impl Ethash {
fn calculate_difficuty(&self, header: &Header, parent: &Header) -> U256 {
const EXP_DIFF_PERIOD: u64 = 100000;
if header.number == 0 {
panic!("Can't calculate genesis block difficulty");
}
let min_difficulty = self.u256_param("minimumDifficulty");
let difficulty_bound_divisor = self.u256_param("difficultyBoundDivisor");
let duration_limit = self.u64_param("durationLimit");
let frontier_limit = self.u64_param("frontierCompatibilityModeLimit");
let mut target = if header.number < frontier_limit {
if header.timestamp >= parent.timestamp + duration_limit {
parent.difficulty - (parent.difficulty / difficulty_bound_divisor)
}
else {
parent.difficulty + (parent.difficulty / difficulty_bound_divisor)
}
}
else {
let diff_inc = (header.timestamp - parent.timestamp) / 10;
if diff_inc <= 1 {
parent.difficulty + parent.difficulty / From::from(2048) * From::from(1 - diff_inc)
}
else {
parent.difficulty - parent.difficulty / From::from(2048) * From::from(max(diff_inc - 1, 99))
}
};
target = max(min_difficulty, target);
let period = ((parent.number + 1) / EXP_DIFF_PERIOD) as usize;
if period > 1 {
target = max(min_difficulty, target + (U256::from(1) << (period - 2)));
}
target
}
fn boundary_to_difficulty(boundary: &H256) -> U256 {
U256::from((U512::one() << 256) / x!(U256::from(boundary.as_slice())))
}
fn to_ethash(hash: H256) -> EH256 {
unsafe { mem::transmute(hash) }
}
fn from_ethash(hash: EH256) -> H256 {
unsafe { mem::transmute(hash) }
}
}
impl Header {
fn nonce(&self) -> u64 {
decode(&self.seal()[1])
}
fn mix_hash(&self) -> H256 {
decode(&self.seal()[0])
}
}
#[test]
fn on_close_block() {
use super::*;
let engine = new_morden().to_engine().unwrap();
let genesis_header = engine.spec().genesis_header();
let mut db = JournalDB::new_temp();
engine.spec().ensure_db_good(&mut db);
let last_hashes = vec![genesis_header.hash()];
let b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
let b = b.close();
assert_eq!(b.state().balance(&Address::zero()), U256::from_str("4563918244f40000").unwrap());
}
#[test]
fn on_close_block_with_uncle() {
use super::*;
let engine = new_morden().to_engine().unwrap();
let genesis_header = engine.spec().genesis_header();
let mut db = JournalDB::new_temp();
engine.spec().ensure_db_good(&mut db);
let last_hashes = vec![genesis_header.hash()];
let mut b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
let mut uncle = Header::new();
let uncle_author = address_from_hex("ef2d6d194084c2de36e0dabfce45d046b37d1106");
uncle.author = uncle_author.clone();
b.push_uncle(uncle).unwrap();
let b = b.close();
assert_eq!(b.state().balance(&Address::zero()), U256::from_str("478eae0e571ba000").unwrap());
assert_eq!(b.state().balance(&uncle_author), U256::from_str("3cb71f51fc558000").unwrap());
}
// TODO: difficulty test