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P2P task per Tributary, not per message
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@kayabaNerve
kayabaNerve committed Sep 26, 2023
1 parent e1801b5 commit 7312428
Showing 1 changed file with 121 additions and 116 deletions.
237 changes: 121 additions & 116 deletions coordinator/src/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -346,134 +346,139 @@ pub async fn handle_p2p<D: Db, P: P2p>(
p2p: P,
mut new_tributary: broadcast::Receiver<ActiveTributary<D, P>>,
) {
let tributaries = Arc::new(RwLock::new(HashMap::new()));
loop {
while let Ok(tributary) = {
match new_tributary.try_recv() {
Ok(tributary) => Ok(tributary),
Err(broadcast::error::TryRecvError::Empty) => Err(()),
Err(broadcast::error::TryRecvError::Lagged(_)) => {
panic!("handle_p2p lagged to handle new_tributary")
}
Err(broadcast::error::TryRecvError::Closed) => panic!("new_tributary sender closed"),
}
} {
// TODO: Because the below maintains a read lock, this will never process until all prior P2P
// messages were handled. That's a notable latency spike
tributaries.write().await.insert(tributary.spec.genesis(), tributary);
}
let channels = Arc::new(RwLock::new(HashMap::new()));
tokio::spawn({
let p2p = p2p.clone();
let channels = channels.clone();
async move {
loop {
let tributary = new_tributary.recv().await.unwrap();
let genesis = tributary.spec.genesis();

let mut msg = p2p.receive().await;
// Spawn a dedicated task to handle this message, ensuring any singularly latent message
// doesn't hold everything up
// TODO: Move to one task per tributary (or two. One for Tendermint, one for Tributary)
tokio::spawn({
let p2p = p2p.clone();
let tributaries = tributaries.clone();
async move {
match msg.kind {
P2pMessageKind::KeepAlive => {}

P2pMessageKind::Tributary(genesis) => {
let tributaries = tributaries.read().await;
let Some(tributary) = tributaries.get(&genesis) else {
log::debug!("received p2p message for unknown network");
return;
};
let (send, mut recv) = mpsc::unbounded_channel();
channels.write().await.insert(genesis, send);

log::trace!("handling message for tributary {:?}", tributary.spec.set());
if tributary.tributary.handle_message(&msg.msg).await {
P2p::broadcast(&p2p, msg.kind, msg.msg).await;
}
}
tokio::spawn({
let p2p = p2p.clone();
async move {
let mut msg: Message<P> = recv.recv().await.unwrap();
match msg.kind {
P2pMessageKind::KeepAlive => {}

P2pMessageKind::Tributary(msg_genesis) => {
assert_eq!(msg_genesis, genesis);
log::trace!("handling message for tributary {:?}", tributary.spec.set());
if tributary.tributary.handle_message(&msg.msg).await {
P2p::broadcast(&p2p, msg.kind, msg.msg).await;
}
}

// TODO2: Rate limit this per timestamp
// And/or slash on Heartbeat which justifies a response, since the node obviously was
// offline and we must now use our bandwidth to compensate for them?
P2pMessageKind::Heartbeat(genesis) => {
if msg.msg.len() != 40 {
log::error!("validator sent invalid heartbeat");
return;
}
// TODO2: Rate limit this per timestamp
// And/or slash on Heartbeat which justifies a response, since the node obviously was
// offline and we must now use our bandwidth to compensate for them?
// TODO: Dedicated task for heartbeats
P2pMessageKind::Heartbeat(msg_genesis) => {
assert_eq!(msg_genesis, genesis);
if msg.msg.len() != 40 {
log::error!("validator sent invalid heartbeat");
return;
}

let tributaries = tributaries.read().await;
let Some(tributary) = tributaries.get(&genesis) else {
log::debug!("received heartbeat message for unknown network");
return;
};
let tributary_read = &tributary.tributary;

/*
// Have sqrt(n) nodes reply with the blocks
let mut responders = (tributary.spec.n() as f32).sqrt().floor() as u64;
// Try to have at least 3 responders
if responders < 3 {
responders = tributary.spec.n().min(3).into();
}
*/

// Have up to three nodes respond
let responders = u64::from(tributary.spec.n().min(3));

// Decide which nodes will respond by using the latest block's hash as a mutually
// agreed upon entropy source
// This isn't a secure source of entropy, yet it's fine for this
let entropy = u64::from_le_bytes(tributary_read.tip().await[.. 8].try_into().unwrap());
// If n = 10, responders = 3, we want start to be 0 ..= 7 (so the highest is 7, 8, 9)
// entropy % (10 + 1) - 3 = entropy % 8 = 0 ..= 7
let start =
usize::try_from(entropy % (u64::from(tributary.spec.n() + 1) - responders)).unwrap();
let mut selected = false;
for validator in
&tributary.spec.validators()[start .. (start + usize::try_from(responders).unwrap())]
{
if our_key == validator.0 {
selected = true;
break;
}
}
if !selected {
log::debug!("received heartbeat and not selected to respond");
return;
}
let tributary_read = &tributary.tributary;

log::debug!("received heartbeat and selected to respond");
/*
// Have sqrt(n) nodes reply with the blocks
let mut responders = (tributary.spec.n() as f32).sqrt().floor() as u64;
// Try to have at least 3 responders
if responders < 3 {
responders = tributary.spec.n().min(3).into();
}
*/

// Have up to three nodes respond
let responders = u64::from(tributary.spec.n().min(3));

// Decide which nodes will respond by using the latest block's hash as a mutually
// agreed upon entropy source
// This isn't a secure source of entropy, yet it's fine for this
let entropy =
u64::from_le_bytes(tributary_read.tip().await[.. 8].try_into().unwrap());
// If n = 10, responders = 3, we want `start` to be 0 ..= 7
// (so the highest is 7, 8, 9)
// entropy % (10 + 1) - 3 = entropy % 8 = 0 ..= 7
let start =
usize::try_from(entropy % (u64::from(tributary.spec.n() + 1) - responders))
.unwrap();
let mut selected = false;
for validator in &tributary.spec.validators()
[start .. (start + usize::try_from(responders).unwrap())]
{
if our_key == validator.0 {
selected = true;
break;
}
}
if !selected {
log::debug!("received heartbeat and not selected to respond");
return;
}

let reader = tributary_read.reader();
log::debug!("received heartbeat and selected to respond");

let mut latest = msg.msg[.. 32].try_into().unwrap();
while let Some(next) = reader.block_after(&latest) {
let mut res = reader.block(&next).unwrap().serialize();
res.extend(reader.commit(&next).unwrap());
// Also include the timestamp used within the Heartbeat
res.extend(&msg.msg[32 .. 40]);
p2p.send(msg.sender, P2pMessageKind::Block(tributary.spec.genesis()), res).await;
latest = next;
}
}
let reader = tributary_read.reader();

P2pMessageKind::Block(genesis) => {
let mut msg_ref: &[u8] = msg.msg.as_ref();
let Ok(block) = Block::<Transaction>::read(&mut msg_ref) else {
log::error!("received block message with an invalidly serialized block");
return;
};
// Get just the commit
msg.msg.drain(.. (msg.msg.len() - msg_ref.len()));
msg.msg.drain((msg.msg.len() - 8) ..);

let tributaries = tributaries.read().await;
let Some(tributary) = tributaries.get(&genesis) else {
log::debug!("received block message for unknown network");
return;
};
let mut latest = msg.msg[.. 32].try_into().unwrap();
while let Some(next) = reader.block_after(&latest) {
let mut res = reader.block(&next).unwrap().serialize();
res.extend(reader.commit(&next).unwrap());
// Also include the timestamp used within the Heartbeat
res.extend(&msg.msg[32 .. 40]);
p2p.send(msg.sender, P2pMessageKind::Block(tributary.spec.genesis()), res).await;
latest = next;
}
}

let res = tributary.tributary.sync_block(block, msg.msg).await;
log::debug!("received block from {:?}, sync_block returned {}", msg.sender, res);
P2pMessageKind::Block(msg_genesis) => {
assert_eq!(msg_genesis, genesis);
let mut msg_ref: &[u8] = msg.msg.as_ref();
let Ok(block) = Block::<Transaction>::read(&mut msg_ref) else {
log::error!("received block message with an invalidly serialized block");
return;
};
// Get just the commit
msg.msg.drain(.. (msg.msg.len() - msg_ref.len()));
msg.msg.drain((msg.msg.len() - 8) ..);

let res = tributary.tributary.sync_block(block, msg.msg).await;
log::debug!("received block from {:?}, sync_block returned {}", msg.sender, res);
}
}
}
});
}
}
});

loop {
let msg = p2p.receive().await;
match msg.kind {
P2pMessageKind::KeepAlive => {}
P2pMessageKind::Tributary(genesis) => {
if let Some(channel) = channels.read().await.get(&genesis) {
channel.send(msg).unwrap();
}
}
});
P2pMessageKind::Heartbeat(genesis) => {
if let Some(channel) = channels.read().await.get(&genesis) {
channel.send(msg).unwrap();
}
}
P2pMessageKind::Block(genesis) => {
if let Some(channel) = channels.read().await.get(&genesis) {
channel.send(msg).unwrap();
}
}
}
}
}

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