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parity-zcash
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median time verfication might be unordered?

This commit is contained in:
NikVolf 2016-11-25 14:54:22 +03:00
parent 9f4469e480
commit a4de321cc7
1 changed files with 18 additions and 18 deletions
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36
verification/src/chain_verifier.rs
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@ -1,6 +1,5 @@
//! Bitcoin chain verifier
use std::cmp;
use std::collections::HashSet;
use db::{self, BlockRef, BlockLocation};
use super::{Verify, VerificationResult, Chain, Error, TransactionError, ContinueVerify};
@ -64,13 +63,6 @@ impl ChainVerifier {
}
}
if let Some(median_timestamp) = self.ordered_median_timestamp(block, at_height) {
if median_timestamp > block.block_header.time {
trace!(target: "verification", "median timestamp verification failed, median: {}, current: {}", median_timestamp, block.block_header.time);
return Err(Error::Timestamp);
}
}
let coinbase_spends = block.transactions()[0].total_spends();
let mut total_unspent = 0u64;
@ -219,6 +211,13 @@ impl ChainVerifier {
return Err(Error::Timestamp);
}
if let Some(median_timestamp) = self.median_timestamp(block) {
if median_timestamp > block.block_header.time {
trace!(target: "verification", "median timestamp verification failed, median: {}, current: {}", median_timestamp, block.block_header.time);
return Err(Error::Timestamp);
}
}
// todo: serialized_size function is at least suboptimal
let size = ::serialization::Serializable::serialized_size(block);
if size > MAX_BLOCK_SIZE {
@ -275,24 +274,25 @@ impl ChainVerifier {
}
}
fn ordered_median_timestamp(&self, block: &chain::Block, height: u32) -> Option<u32> {
if height == 0 {
return None;
}
fn median_timestamp(&self, block: &chain::Block) -> Option<u32> {
// TODO: make 11 a const
let max = cmp::min(height, 11);
let mut timestamps = HashSet::new();
let mut block_ref = block.block_header.previous_header_hash.clone().into();
// TODO: optimize it, so it does not make 11 redundant queries each time
for _ in 0..max {
let previous_header = self.store.block_header(block_ref).expect("block_ref < height; qed");
for _ in 0..10 {
let previous_header = match self.store.block_header(block_ref) {
Some(h) => h,
None => { break; }
};
timestamps.insert(previous_header.time);
block_ref = previous_header.previous_header_hash.into();
}
let timestamps: Vec<_> = timestamps.into_iter().collect();
Some(timestamps[timestamps.len() / 2])
if timestamps.len() > 2 {
let timestamps: Vec<_> = timestamps.into_iter().collect();
Some(timestamps[timestamps.len() / 2])
}
else { None }
}
fn work_required(&self, height: u32) -> Option<u32> {