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Replace ExternalBlock with Batch

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The initial TODO was simply to use one ExternalBlock per all batches in the
block. This would require publishing ExternalBlock after the last batch,
requiring knowing the last batch. While we could add such a pipeline, it'd
require:

1) Initial preprocesses using a distinct message from BatchPreprocess
2) An additional message sent after all BatchPreprocess are sent

Unfortunately, both would require tweaks to the SubstrateSigner which aren't
worth the complexity compared to the solution here, at least, not at this time.

While this will cause, if a Tributary is signing a block whose total batch data
exceeds 25 kB, to use multiple transactions which could be optimized out by
'better' local data pipelining, that's an extreme edge case. Given the temporal
nature of each Tributary, it's also an acceptable edge.

This does no longer achieve synchrony over external blocks accordingly. While
signed batches have synchrony, as they embed their block hash, batches being
signed don't have cryptographic synchrony on their contents. This means
validators who are eclipsed may produce invalid shares, as they sign a
different batch. This will be introduced in a follow-up commit.
This commit is contained in:
Luke Parker
2023-08-31 22:48:02 -04:00
parent 2dc35193c9
commit 9a5f8fc5dd
7 changed files with 58 additions and 120 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
coordinator/src/main.rs
View File

@@ -180,7 +180,7 @@ pub async fn scan_tributaries<
D: Db,
Pro: Processors,
P: P2p,
FRid: Future<Output = Vec<[u8; 32]>>,
FRid: Future<Output = ()>,
RID: Clone + Fn(NetworkId, [u8; 32], RecognizedIdType, [u8; 32]) -> FRid,
>(
raw_db: D,
@@ -590,19 +590,17 @@ pub async fn handle_processors<D: Db, Pro: Processors, P: P2p>(
id.attempt,
hex::encode(block),
);
// If this is the first attempt instance, synchronize around the block first
// If this is the first attempt instance, wait until we synchronize around the batch
// first
if id.attempt == 0 {
// Save the preprocess to disk so we can publish it later
// This is fine to use its own TX since it's static and just needs to be written
// before this message finishes it handling (or with this message's finished handling)
let mut txn = db.txn();
MainDb::<D>::save_first_preprocess(&mut txn, id.id, preprocess);
MainDb::<D>::add_batch_to_block(&mut txn, msg.network, block, id.id);
txn.commit();
// TODO: This will publish one ExternalBlock per Batch. We should only publish one per
// all batches within a block
Some(Transaction::ExternalBlock(block.0))
Some(Transaction::Batch(id.id))
} else {
Some(Transaction::BatchPreprocess(SignData {
plan: id.id,
@@ -787,11 +785,11 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
async move {
// SubstrateBlockAck is fired before Preprocess, creating a race between Tributary ack
// of the SubstrateBlock and the sending of all Preprocesses
// A similar race condition exists when multiple Batches are present in a block
// This waits until the necessary preprocess is available
let get_preprocess = |raw_db, id| async move {
loop {
let Some(preprocess) = MainDb::<D>::first_preprocess(raw_db, id) else {
assert_eq!(id_type, RecognizedIdType::Plan);
sleep(Duration::from_millis(100)).await;
continue;
};
@@ -799,53 +797,37 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
}
};
let (ids, txs) = match id_type {
RecognizedIdType::Block => {
let block = id;
let mut tx = match id_type {
RecognizedIdType::Batch => Transaction::BatchPreprocess(SignData {
plan: id,
attempt: 0,
data: get_preprocess(&raw_db, id).await,
signed: Transaction::empty_signed(),
}),
let ids = MainDb::<D>::batches_in_block(&raw_db, network, block);
let mut txs = vec![];
for id in &ids {
txs.push(Transaction::BatchPreprocess(SignData {
plan: *id,
attempt: 0,
data: get_preprocess(&raw_db, *id).await,
signed: Transaction::empty_signed(),
}));
}
(ids, txs)
}
RecognizedIdType::Plan => (
vec![id],
vec![Transaction::SignPreprocess(SignData {
plan: id,
attempt: 0,
data: get_preprocess(&raw_db, id).await,
signed: Transaction::empty_signed(),
})],
),
RecognizedIdType::Plan => Transaction::SignPreprocess(SignData {
plan: id,
attempt: 0,
data: get_preprocess(&raw_db, id).await,
signed: Transaction::empty_signed(),
}),
};
let tributaries = tributaries.read().await;
let Some(tributary) = tributaries.get(&genesis) else {
panic!("tributary we don't have came to consensus on an ExternalBlock");
panic!("tributary we don't have came to consensus on an Batch");
};
let tributary = tributary.tributary.read().await;
for mut tx in txs {
// TODO: Same note as prior nonce acquisition
log::trace!("getting next nonce for Tributary TX containing Batch signing data");
let nonce = tributary
.next_nonce(Ristretto::generator() * key.deref())
.await
.expect("publishing a TX to a tributary we aren't in");
tx.sign(&mut OsRng, genesis, &key, nonce);
// TODO: Same note as prior nonce acquisition
log::trace!("getting next nonce for Tributary TX containing Batch signing data");
let nonce = tributary
.next_nonce(Ristretto::generator() * key.deref())
.await
.expect("publishing a TX to a tributary we aren't in");
tx.sign(&mut OsRng, genesis, &key, nonce);
publish_transaction(&tributary, tx).await;
}
ids
publish_transaction(&tributary, tx).await;
}
}
};