Do not always persist ChannelManager on channel_update messages
authorMatt Corallo <git@bluematt.me>
Mon, 28 Jun 2021 00:54:24 +0000 (00:54 +0000)
committerMatt Corallo <git@bluematt.me>
Wed, 30 Jun 2021 16:13:48 +0000 (16:13 +0000)
If we receive a `channel_update` message for a channel unrelated to
our own, we shouldn't trigger a persistence of our
`ChannelManager`. This avoids significant persistence traffic during
initial node startup.

lightning/src/ln/channel.rs
lightning/src/ln/channelmanager.rs

index 5f5bc51dbb14c3b205847994f238131d2e4c2fbb..2f447c86155ffc78853f1516b2e44e120adb8b0f 100644 (file)
@@ -288,7 +288,7 @@ impl HTLCCandidate {
 }
 
 /// Information needed for constructing an invoice route hint for this channel.
-#[derive(Clone)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct CounterpartyForwardingInfo {
        /// Base routing fee in millisatoshis.
        pub fee_base_msat: u32,
index f72c76e7ac3eeb7b3944b3f99c42debeab013a90..e536d462c6eb5db3ba6a9f3dbfce3de1c78e46d6 100644 (file)
@@ -632,7 +632,7 @@ const CHECK_CLTV_EXPIRY_SANITY: u32 = MIN_CLTV_EXPIRY_DELTA as u32 - LATENCY_GRA
 const CHECK_CLTV_EXPIRY_SANITY_2: u32 = MIN_CLTV_EXPIRY_DELTA as u32 - LATENCY_GRACE_PERIOD_BLOCKS - 2*CLTV_CLAIM_BUFFER;
 
 /// Details of a channel, as returned by ChannelManager::list_channels and ChannelManager::list_usable_channels
-#[derive(Clone)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct ChannelDetails {
        /// The channel's ID (prior to funding transaction generation, this is a random 32 bytes,
        /// thereafter this is the txid of the funding transaction xor the funding transaction output).
@@ -3346,14 +3346,15 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                Ok(())
        }
 
-       fn internal_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) -> Result<(), MsgHandleErrInternal> {
+       /// Returns ShouldPersist if anything changed, otherwise either SkipPersist or an Err.
+       fn internal_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) -> Result<NotifyOption, MsgHandleErrInternal> {
                let mut channel_state_lock = self.channel_state.lock().unwrap();
                let channel_state = &mut *channel_state_lock;
                let chan_id = match channel_state.short_to_id.get(&msg.contents.short_channel_id) {
                        Some(chan_id) => chan_id.clone(),
                        None => {
                                // It's not a local channel
-                               return Ok(())
+                               return Ok(NotifyOption::SkipPersist)
                        }
                };
                match channel_state.by_id.entry(chan_id) {
@@ -3363,7 +3364,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                // If the announcement is about a channel of ours which is public, some
                                                // other peer may simply be forwarding all its gossip to us. Don't provide
                                                // a scary-looking error message and return Ok instead.
-                                               return Ok(());
+                                               return Ok(NotifyOption::SkipPersist);
                                        }
                                        return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a channel_update for a channel from the wrong node - it shouldn't know about our private channels!".to_owned(), chan_id));
                                }
@@ -3371,7 +3372,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        },
                        hash_map::Entry::Vacant(_) => unreachable!()
                }
-               Ok(())
+               Ok(NotifyOption::DoPersist)
        }
 
        fn internal_channel_reestablish(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReestablish) -> Result<(), MsgHandleErrInternal> {
@@ -4116,8 +4117,13 @@ impl<Signer: Sign, M: Deref , T: Deref , K: Deref , F: Deref , L: Deref >
        }
 
        fn handle_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) {
-               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
-               let _ = handle_error!(self, self.internal_channel_update(counterparty_node_id, msg), *counterparty_node_id);
+               PersistenceNotifierGuard::optionally_notify(&self.total_consistency_lock, &self.persistence_notifier, || {
+                       if let Ok(persist) = handle_error!(self, self.internal_channel_update(counterparty_node_id, msg), *counterparty_node_id) {
+                               persist
+                       } else {
+                               NotifyOption::SkipPersist
+                       }
+               });
        }
 
        fn handle_channel_reestablish(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReestablish) {
@@ -4823,6 +4829,9 @@ mod tests {
        use core::sync::atomic::{AtomicBool, Ordering};
        use std::thread;
        use core::time::Duration;
+       use ln::functional_test_utils::*;
+       use ln::features::InitFeatures;
+       use ln::msgs::ChannelMessageHandler;
 
        #[test]
        fn test_wait_timeout() {
@@ -4865,6 +4874,53 @@ mod tests {
                        }
                }
        }
+
+       #[test]
+       fn test_notify_limits() {
+               // Check that a few cases which don't require the persistence of a new ChannelManager,
+               // indeed, do not cause the persistence of a new ChannelManager.
+               let chanmon_cfgs = create_chanmon_cfgs(3);
+               let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
+               let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
+               let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+
+               let mut chan = create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
+
+               // We check that the channel info nodes have doesn't change too early, even though we try
+               // to connect messages with new values
+               chan.0.contents.fee_base_msat *= 2;
+               chan.1.contents.fee_base_msat *= 2;
+               let node_a_chan_info = nodes[0].node.list_channels()[0].clone();
+               let node_b_chan_info = nodes[1].node.list_channels()[0].clone();
+
+               // The first two nodes (which opened a channel) should now require fresh persistence
+               assert!(nodes[0].node.await_persistable_update_timeout(Duration::from_millis(1)));
+               assert!(nodes[1].node.await_persistable_update_timeout(Duration::from_millis(1)));
+               // ... but the last node should not.
+               assert!(!nodes[2].node.await_persistable_update_timeout(Duration::from_millis(1)));
+               // After persisting the first two nodes they should no longer need fresh persistence.
+               assert!(!nodes[0].node.await_persistable_update_timeout(Duration::from_millis(1)));
+               assert!(!nodes[1].node.await_persistable_update_timeout(Duration::from_millis(1)));
+
+               // Node 3, unrelated to the only channel, shouldn't care if it receives a channel_update
+               // about the channel.
+               nodes[2].node.handle_channel_update(&nodes[1].node.get_our_node_id(), &chan.0);
+               nodes[2].node.handle_channel_update(&nodes[1].node.get_our_node_id(), &chan.1);
+               assert!(!nodes[2].node.await_persistable_update_timeout(Duration::from_millis(1)));
+
+               // The nodes which are a party to the channel should also ignore messages from unrelated
+               // parties.
+               nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan.0);
+               nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan.1);
+               nodes[1].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan.0);
+               nodes[1].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan.1);
+               assert!(!nodes[0].node.await_persistable_update_timeout(Duration::from_millis(1)));
+               assert!(!nodes[1].node.await_persistable_update_timeout(Duration::from_millis(1)));
+
+               // At this point the channel info given by peers should still be the same.
+               assert_eq!(nodes[0].node.list_channels()[0], node_a_chan_info);
+               assert_eq!(nodes[1].node.list_channels()[0], node_b_chan_info);
+       }
 }
 
 #[cfg(all(any(test, feature = "_test_utils"), feature = "unstable"))]