openethereum/src/verification.rs

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/// Block and transaction verification functions
///
/// Block verification is done in 3 steps
/// 1. Quick verification upon adding to the block queue
/// 2. Signatures verification done in the queue.
/// 3. Final verification against the blockchain done before enactment.
use common::*;
use engine::Engine;
use blockchain::BlockChain;
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/// Phase 1 quick block verification. Only does checks that are cheap. Operates on a single block
pub fn verify_block_basic(bytes: &[u8], engine: &Engine) -> Result<(), Error> {
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let block = BlockView::new(bytes);
let header = block.header();
try!(verify_header(&header));
try!(verify_block_integrity(bytes, &header.transactions_root, &header.uncles_hash));
try!(engine.verify_block_basic(&header, Some(bytes)));
for u in Rlp::new(bytes).at(2).iter().map(|rlp| rlp.as_val::<Header>()) {
try!(verify_header(&u));
try!(engine.verify_block_basic(&u, None));
}
Ok(())
}
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/// Phase 2 verification. Perform costly checks such as transaction signatures and block nonce for ethash.
/// Still operates on a individual block
/// TODO: return cached transactions, header hash.
pub fn verify_block_unordered(bytes: &[u8], engine: &Engine) -> Result<(), Error> {
let block = BlockView::new(bytes);
let header = block.header();
try!(engine.verify_block_unordered(&header, Some(bytes)));
for u in Rlp::new(bytes).at(2).iter().map(|rlp| rlp.as_val::<Header>()) {
try!(engine.verify_block_unordered(&u, None));
}
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Ok(())
}
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/// Phase 3 verification. Check block information against parent and uncles.
pub fn verify_block_final(bytes: &[u8], engine: &Engine, bc: &BlockChain) -> Result<(), Error> {
let block = BlockView::new(bytes);
let header = block.header();
let parent = try!(bc.block_header(&header.parent_hash).ok_or::<Error>(From::from(BlockError::UnknownParent(header.parent_hash.clone()))));
try!(verify_parent(&header, &parent));
try!(engine.verify_block_final(&header, &parent, Some(bytes)));
let num_uncles = Rlp::new(bytes).at(2).item_count();
if num_uncles != 0 {
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if num_uncles > engine.maximum_uncle_count() {
return Err(From::from(BlockError::TooManyUncles(OutOfBounds { min: 0, max: engine.maximum_uncle_count(), found: num_uncles })));
}
let mut excluded = HashSet::new();
excluded.insert(header.hash());
let mut hash = header.parent_hash.clone();
excluded.insert(hash.clone());
for _ in 0..6 {
match bc.block_details(&hash) {
Some(details) => {
excluded.insert(details.parent.clone());
let b = bc.block(&hash).unwrap();
excluded.extend(BlockView::new(&b).uncle_hashes());
hash = details.parent;
}
None => break
}
}
for uncle in Rlp::new(bytes).at(2).iter().map(|rlp| rlp.as_val::<Header>()) {
let uncle_parent = try!(bc.block_header(&uncle.parent_hash).ok_or::<Error>(From::from(BlockError::UnknownUncleParent(uncle.parent_hash.clone()))));
if excluded.contains(&uncle_parent.hash()) {
return Err(From::from(BlockError::UncleInChain(uncle_parent.hash())))
}
// m_currentBlock.number() - uncle.number() m_cB.n - uP.n()
// 1 2
// 2
// 3
// 4
// 5
// 6 7
// (8 Invalid)
let depth = if header.number > uncle.number { header.number - uncle.number } else { 0 };
if depth > 6 {
return Err(From::from(BlockError::UncleTooOld(OutOfBounds { min: header.number - depth, max: header.number - 1, found: uncle.number })));
}
else if depth < 1 {
return Err(From::from(BlockError::UncleIsBrother(OutOfBounds { min: header.number - depth, max: header.number - 1, found: uncle.number })));
}
// cB
// cB.p^1 1 depth, valid uncle
// cB.p^2 ---/ 2
// cB.p^3 -----/ 3
// cB.p^4 -------/ 4
// cB.p^5 ---------/ 5
// cB.p^6 -----------/ 6
// cB.p^7 -------------/
// cB.p^8
let mut expected_uncle_parent = header.parent_hash.clone();
for _ in 0..depth {
expected_uncle_parent = bc.block_details(&expected_uncle_parent).unwrap().parent;
}
if expected_uncle_parent != uncle_parent.hash() {
return Err(From::from(BlockError::UncleParentNotInChain(uncle_parent.hash())));
}
try!(engine.verify_block_final(&uncle, &uncle_parent, Some(bytes)));
}
}
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Ok(())
}
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/// Check basic header parameters.
fn verify_header(header: &Header) -> Result<(), Error> {
if header.number > From::from(BlockNumber::max_value()) {
return Err(From::from(BlockError::InvalidNumber(OutOfBounds { max: From::from(BlockNumber::max_value()), min: 0, found: header.number })))
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}
if header.gas_used > header.gas_limit {
return Err(From::from(BlockError::TooMuchGasUsed(OutOfBounds { max: header.gas_limit, min: From::from(0), found: header.gas_used })));
}
Ok(())
}
/// Check header parameters agains parent header.
fn verify_parent(header: &Header, parent: &Header) -> Result<(), Error> {
if !header.parent_hash.is_zero() && parent.hash() != header.parent_hash {
return Err(From::from(BlockError::InvalidParentHash(Mismatch { expected: parent.hash(), found: header.parent_hash.clone() })))
}
if header.timestamp <= parent.timestamp {
return Err(From::from(BlockError::InvalidTimestamp(OutOfBounds { max: u64::max_value(), min: parent.timestamp + 1, found: header.timestamp })))
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}
if header.number <= parent.number {
return Err(From::from(BlockError::InvalidNumber(OutOfBounds { max: BlockNumber::max_value(), min: parent.number + 1, found: header.number })));
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}
Ok(())
}
/// Verify block data against header: transactions root and uncles hash.
fn verify_block_integrity(block: &[u8], transactions_root: &H256, uncles_hash: &H256) -> Result<(), Error> {
let block = Rlp::new(block);
let tx = block.at(1);
let expected_root = &ordered_trie_root(tx.iter().map(|r| r.as_raw().to_vec()).collect()); //TODO: get rid of vectors here
if expected_root != transactions_root {
return Err(From::from(BlockError::InvalidTransactionsRoot(Mismatch { expected: expected_root.clone(), found: transactions_root.clone() })))
}
let expected_uncles = &block.at(2).as_raw().sha3();
if expected_uncles != uncles_hash {
return Err(From::from(BlockError::InvalidUnclesHash(Mismatch { expected: expected_uncles.clone(), found: uncles_hash.clone() })))
}
Ok(())
}