Files
serai/coordinator/src/tributary/scanner.rs
Luke Parker 065d314e2a Further expand clippy workspace lints
Achieves a notable amount of reduced async and clones.
2023-12-17 00:04:49 -05:00

548 lines
18 KiB
Rust

use core::{marker::PhantomData, ops::Deref, future::Future, time::Duration};
use std::sync::Arc;
use zeroize::Zeroizing;
use ciphersuite::{group::GroupEncoding, Ciphersuite, Ristretto};
use frost::Participant;
use tokio::sync::broadcast;
use scale::{Encode, Decode};
use serai_client::{
primitives::{SeraiAddress, Signature},
validator_sets::primitives::{KeyPair, ValidatorSet},
Serai,
};
use serai_db::DbTxn;
use processor_messages::coordinator::SubstrateSignableId;
use tributary::{
TransactionKind, Transaction as TributaryTransaction, TransactionError, Block, TributaryReader,
tendermint::{
tx::{TendermintTx, Evidence, decode_signed_message},
TendermintNetwork,
},
};
use crate::{Db, processors::Processors, substrate::BatchInstructionsHashDb, tributary::*, P2p};
#[derive(Clone, Copy, PartialEq, Eq, Debug, Encode, Decode)]
pub enum RecognizedIdType {
Batch,
Plan,
}
#[async_trait::async_trait]
pub trait RIDTrait {
async fn recognized_id(
&self,
set: ValidatorSet,
genesis: [u8; 32],
kind: RecognizedIdType,
id: Vec<u8>,
);
}
#[async_trait::async_trait]
impl<
FRid: Send + Future<Output = ()>,
F: Sync + Fn(ValidatorSet, [u8; 32], RecognizedIdType, Vec<u8>) -> FRid,
> RIDTrait for F
{
async fn recognized_id(
&self,
set: ValidatorSet,
genesis: [u8; 32],
kind: RecognizedIdType,
id: Vec<u8>,
) {
(self)(set, genesis, kind, id).await
}
}
#[async_trait::async_trait]
pub trait PublishSeraiTransaction {
async fn publish_set_keys(
&self,
set: ValidatorSet,
removed: Vec<SeraiAddress>,
key_pair: KeyPair,
signature: Signature,
);
}
mod impl_pst_for_serai {
use super::*;
use serai_client::SeraiValidatorSets;
// Uses a macro because Rust can't resolve the lifetimes/generics around the check function
// check is expected to return true if the effect has already occurred
// The generated publish function will return true if *we* published the transaction
macro_rules! common_pst {
($Meta: ty, $check: ident) => {
async fn publish(
serai: &Serai,
set: ValidatorSet,
tx: serai_client::Transaction,
meta: $Meta,
) -> bool {
loop {
match serai.publish(&tx).await {
Ok(_) => return true,
// This is assumed to be some ephemeral error due to the assumed fault-free
// creation
// TODO2: Differentiate connection errors from invariants
Err(e) => {
if let Ok(serai) = serai.as_of_latest_finalized_block().await {
let serai = serai.validator_sets();
// The following block is irrelevant, and can/likely will fail, if we're publishing
// a TX for an old session
// If we're on a newer session, move on
if let Ok(Some(current_session)) = serai.session(set.network).await {
if current_session.0 > set.session.0 {
log::warn!(
"trying to publish a TX relevant to set {set:?} which isn't the latest"
);
return false;
}
}
// Check if someone else published the TX in question
if $check(serai, set, meta).await {
return false;
}
log::error!("couldn't connect to Serai node to publish TX: {e:?}");
tokio::time::sleep(core::time::Duration::from_secs(5)).await;
}
}
}
}
}
};
}
#[async_trait::async_trait]
impl PublishSeraiTransaction for Serai {
async fn publish_set_keys(
&self,
set: ValidatorSet,
removed: Vec<SeraiAddress>,
key_pair: KeyPair,
signature: Signature,
) {
let tx = SeraiValidatorSets::set_keys(set.network, removed, key_pair, signature);
async fn check(serai: SeraiValidatorSets<'_>, set: ValidatorSet, (): ()) -> bool {
if matches!(serai.keys(set).await, Ok(Some(_))) {
log::info!("another coordinator set key pair for {:?}", set);
return true;
}
false
}
common_pst!((), check);
if publish(self, set, tx, ()).await {
log::info!("published set keys for {set:?}");
}
}
}
}
#[async_trait::async_trait]
pub trait PTTTrait {
async fn publish_tributary_tx(&self, tx: Transaction);
}
#[async_trait::async_trait]
impl<FPtt: Send + Future<Output = ()>, F: Sync + Fn(Transaction) -> FPtt> PTTTrait for F {
async fn publish_tributary_tx(&self, tx: Transaction) {
(self)(tx).await
}
}
pub struct TributaryBlockHandler<
'a,
T: DbTxn,
Pro: Processors,
PST: PublishSeraiTransaction,
PTT: PTTTrait,
RID: RIDTrait,
P: P2p,
> {
pub txn: &'a mut T,
pub our_key: &'a Zeroizing<<Ristretto as Ciphersuite>::F>,
pub recognized_id: &'a RID,
pub processors: &'a Pro,
pub publish_serai_tx: &'a PST,
pub publish_tributary_tx: &'a PTT,
pub spec: &'a TributarySpec,
block: Block<Transaction>,
pub block_number: u32,
_p2p: PhantomData<P>,
}
impl<
T: DbTxn,
Pro: Processors,
PST: PublishSeraiTransaction,
PTT: PTTTrait,
RID: RIDTrait,
P: P2p,
> TributaryBlockHandler<'_, T, Pro, PST, PTT, RID, P>
{
pub fn fatal_slash(&mut self, slashing: [u8; 32], reason: &str) {
// TODO: If this fatal slash puts the remaining set below the threshold, spin
let genesis = self.spec.genesis();
log::warn!("fatally slashing {}. reason: {}", hex::encode(slashing), reason);
FatallySlashed::set_fatally_slashed(self.txn, genesis, slashing);
// TODO: disconnect the node from network/ban from further participation in all Tributaries
// TODO: If during DKG, trigger a re-attempt
// Despite triggering a re-attempt, this DKG may still complete and may become in-use
}
// TODO: Once Substrate confirms a key, we need to rotate our validator set OR form a second
// Tributary post-DKG
// https://github.com/serai-dex/serai/issues/426
pub fn fatal_slash_with_participant_index(
&mut self,
removed: &[<Ristretto as Ciphersuite>::G],
i: Participant,
reason: &str,
) {
// Resolve from Participant to <Ristretto as Ciphersuite>::G
let i = u16::from(i);
let mut validator = None;
for (potential, _) in self.spec.validators() {
let v_i = self.spec.i(removed, potential).unwrap();
if (u16::from(v_i.start) <= i) && (i < u16::from(v_i.end)) {
validator = Some(potential);
break;
}
}
let validator = validator.unwrap();
self.fatal_slash(validator.to_bytes(), reason);
}
async fn handle<D: Db>(mut self) {
log::info!("found block for Tributary {:?}", self.spec.set());
let transactions = self.block.transactions.clone();
for tx in transactions {
match tx {
TributaryTransaction::Tendermint(TendermintTx::SlashEvidence(ev)) => {
// Since the evidence is on the chain, it should already have been validated
// We can just punish the signer
let data = match ev {
Evidence::ConflictingMessages(first, second) |
Evidence::ConflictingPrecommit(first, second) => (first, Some(second)),
Evidence::InvalidPrecommit(first) | Evidence::InvalidValidRound(first) => (first, None),
};
let msgs = (
decode_signed_message::<TendermintNetwork<D, Transaction, P>>(&data.0).unwrap(),
if data.1.is_some() {
Some(
decode_signed_message::<TendermintNetwork<D, Transaction, P>>(&data.1.unwrap())
.unwrap(),
)
} else {
None
},
);
// Since anything with evidence is fundamentally faulty behavior, not just temporal
// errors, mark the node as fatally slashed
self.fatal_slash(msgs.0.msg.sender, &format!("invalid tendermint messages: {msgs:?}"));
}
TributaryTransaction::Application(tx) => {
self.handle_application_tx(tx).await;
}
}
}
let genesis = self.spec.genesis();
for topic in ReattemptDb::take(self.txn, genesis, self.block_number) {
let attempt = AttemptDb::start_next_attempt(self.txn, genesis, topic);
log::info!("re-attempting {topic:?} with attempt {attempt}");
/*
All of these have the same common flow:
1) Check if this re-attempt is actually needed
2) If so, dispatch whatever events as needed
This is because we *always* re-attempt any protocol which had participation. That doesn't
mean we *should* re-attempt this protocol.
The alternatives were:
1) Note on-chain we completed a protocol, halting re-attempts upon 34%.
2) Vote on-chain to re-attempt a protocol.
This schema doesn't have any additional messages upon the success case (whereas
alternative #1 does) and doesn't have overhead (as alternative #2 does, sending votes and
then preprocesses. This only sends preprocesses).
*/
match topic {
Topic::Dkg => {
FatalSlashesAsOfDkgAttempt::set(
self.txn,
genesis,
attempt,
&FatalSlashes::get(self.txn, genesis).unwrap_or(vec![]),
);
if DkgCompleted::get(self.txn, genesis).is_none() {
// Since it wasn't completed, instruct the processor to start the next attempt
let id =
processor_messages::key_gen::KeyGenId { session: self.spec.set().session, attempt };
let removed = crate::tributary::latest_removed(self.txn, genesis);
let our_i =
self.spec.i(&removed, Ristretto::generator() * self.our_key.deref()).unwrap();
// TODO: Don't fatal slash, yet don't include, parties who have been offline so long as
// we still meet the needed threshold. This will have to have any parties removed for
// being offline, who aren't participating in the confirmed key, drop the Tributary and
// notify their processor.
// TODO: Instead of DKG confirmations taking a n-of-n MuSig, have it take a t-of-n with
// a specification of those explicitly removed and those removed due to being offline.
let params =
frost::ThresholdParams::new(self.spec.t(), self.spec.n(&removed), our_i.start)
.unwrap();
let shares = u16::from(our_i.end) - u16::from(our_i.start);
self
.processors
.send(
self.spec.set().network,
processor_messages::key_gen::CoordinatorMessage::GenerateKey { id, params, shares },
)
.await;
}
}
Topic::DkgConfirmation => {
panic!("re-attempting DkgConfirmation when we should be re-attempting the Dkg")
}
Topic::SubstrateSign(inner_id) => {
let id = processor_messages::coordinator::SubstrateSignId {
session: self.spec.set().session,
id: inner_id,
attempt,
};
match inner_id {
SubstrateSignableId::CosigningSubstrateBlock(block) => {
let block_number = SeraiBlockNumber::get(self.txn, block)
.expect("couldn't get the block number for prior attempted cosign");
// Check if the cosigner has a signature from our set for this block/a newer one
let latest_cosign =
crate::cosign_evaluator::LatestCosign::get(self.txn, self.spec.set().network)
.map_or(0, |cosign| cosign.block_number);
if latest_cosign < block_number {
// Instruct the processor to start the next attempt
self
.processors
.send(
self.spec.set().network,
processor_messages::coordinator::CoordinatorMessage::CosignSubstrateBlock {
id,
block_number,
},
)
.await;
}
}
SubstrateSignableId::Batch(batch) => {
// If the Batch hasn't appeared on-chain...
if BatchInstructionsHashDb::get(self.txn, self.spec.set().network, batch).is_none() {
// Instruct the processor to start the next attempt
// The processor won't continue if it's already signed a Batch
// Prior checking if the Batch is on-chain just may reduce the non-participating
// 33% from publishing their re-attempt messages
self
.processors
.send(
self.spec.set().network,
processor_messages::coordinator::CoordinatorMessage::BatchReattempt { id },
)
.await;
}
}
}
}
Topic::Sign(id) => {
// Instruct the processor to start the next attempt
// If it has already noted a completion, it won't send a preprocess and will simply drop
// the re-attempt message
self
.processors
.send(
self.spec.set().network,
processor_messages::sign::CoordinatorMessage::Reattempt {
id: processor_messages::sign::SignId {
session: self.spec.set().session,
id,
attempt,
},
},
)
.await;
}
}
}
}
}
#[allow(clippy::too_many_arguments)]
pub(crate) async fn handle_new_blocks<
D: Db,
Pro: Processors,
PST: PublishSeraiTransaction,
PTT: PTTTrait,
RID: RIDTrait,
P: P2p,
>(
db: &mut D,
key: &Zeroizing<<Ristretto as Ciphersuite>::F>,
recognized_id: &RID,
processors: &Pro,
publish_serai_tx: &PST,
publish_tributary_tx: &PTT,
spec: &TributarySpec,
tributary: &TributaryReader<D, Transaction>,
) {
let genesis = tributary.genesis();
let mut last_block = LastHandledBlock::get(db, genesis).unwrap_or(genesis);
let mut block_number = TributaryBlockNumber::get(db, last_block).unwrap_or(0);
while let Some(next) = tributary.block_after(&last_block) {
let block = tributary.block(&next).unwrap();
block_number += 1;
// Make sure we have all of the provided transactions for this block
for tx in &block.transactions {
// Provided TXs will appear first in the Block, so we can break after we hit a non-Provided
let TransactionKind::Provided(order) = tx.kind() else {
break;
};
// make sure we have all the provided txs in this block locally
if !tributary.locally_provided_txs_in_block(&block.hash(), order) {
return;
}
}
let mut txn = db.txn();
TributaryBlockNumber::set(&mut txn, next, &block_number);
(TributaryBlockHandler {
txn: &mut txn,
spec,
our_key: key,
recognized_id,
processors,
publish_serai_tx,
publish_tributary_tx,
block,
block_number,
_p2p: PhantomData::<P>,
})
.handle::<D>()
.await;
last_block = next;
LastHandledBlock::set(&mut txn, genesis, &next);
txn.commit();
}
}
pub(crate) async fn scan_tributaries_task<
D: Db,
Pro: Processors,
P: P2p,
RID: 'static + Send + Sync + Clone + RIDTrait,
>(
raw_db: D,
key: Zeroizing<<Ristretto as Ciphersuite>::F>,
recognized_id: RID,
processors: Pro,
serai: Arc<Serai>,
mut tributary_event: broadcast::Receiver<crate::TributaryEvent<D, P>>,
) {
log::info!("scanning tributaries");
loop {
match tributary_event.recv().await {
Ok(crate::TributaryEvent::NewTributary(crate::ActiveTributary { spec, tributary })) => {
// For each Tributary, spawn a dedicated scanner task
tokio::spawn({
let raw_db = raw_db.clone();
let key = key.clone();
let recognized_id = recognized_id.clone();
let processors = processors.clone();
let serai = serai.clone();
async move {
let spec = &spec;
let reader = tributary.reader();
let mut tributary_db = raw_db.clone();
loop {
// Check if the set was retired, and if so, don't further operate
if crate::db::RetiredTributaryDb::get(&raw_db, spec.set()).is_some() {
break;
}
// Obtain the next block notification now to prevent obtaining it immediately after
// the next block occurs
let next_block_notification = tributary.next_block_notification().await;
handle_new_blocks::<_, _, _, _, _, P>(
&mut tributary_db,
&key,
&recognized_id,
&processors,
&*serai,
&|tx: Transaction| {
let tributary = tributary.clone();
async move {
match tributary.add_transaction(tx.clone()).await {
Ok(_) => {}
// Can happen as this occurs on a distinct DB TXN
Err(TransactionError::InvalidNonce) => {
log::warn!(
"publishing TX {tx:?} returned InvalidNonce. was it already added?"
)
}
Err(e) => panic!("created an invalid transaction: {e:?}"),
}
}
},
spec,
&reader,
)
.await;
// Run either when the notification fires, or every interval of block_time
let _ = tokio::time::timeout(
Duration::from_secs(tributary::Tributary::<D, Transaction, P>::block_time().into()),
next_block_notification,
)
.await;
}
}
});
}
// The above loop simply checks the DB every few seconds, voiding the need for this event
Ok(crate::TributaryEvent::TributaryRetired(_)) => {}
Err(broadcast::error::RecvError::Lagged(_)) => {
panic!("scan_tributaries lagged to handle tributary_event")
}
Err(broadcast::error::RecvError::Closed) => panic!("tributary_event sender closed"),
}
}
}