In this commit, we remove the per channel `sigPool` within the
`lnwallet.LightningChannel` struct. With this change, we ensure that as
the number of channels grows, the number of gouroutines idling in the
sigPool stays constant. It's the case that currently on the daemon, most
channels are likely inactive, with only a hand full actually
consistently carrying out channel updates. As a result, this change
should reduce the amount of idle CPU usage, as we have less active
goroutines in select loops.
In order to make this change, the `SigPool` itself has been publicly
exported such that outside callers can make a `SigPool` and pass it into
newly created channels. Since the sig pool now lives outside the
channel, we were also able to do away with the Stop() method on the
channel all together.
Finally, the server is the sub-system that is currently responsible for
managing the `SigPool` within lnd.
This commit makes the AddNewChannel expect a OpenChannel instead of a
LightningChannel struct. This moves the responsibility for starting the
LightningChannel from the fundingmanager to the peer, and we can defer
the channel restoration until we know that the channel is not already
active.
In this commit, we also check ErrEdgeNotFound when attempting to send an
active/inactive channel update for a channel to the network. We do this
as it's possible that a channel has confirmed, but it still does not
meet the required number of confirmations to be publicly announced.
In this commit, we fix a small bug with regards to the persistent peer
connection pruning logic. Before this commit, it'd be the case that we'd
prune a persistent connection to a peer if all links happen to be
inactive. This isn't ideal, as the channels are still open, so we should
always be atttempting to connect to them. We fix this by looking at the
set of channels on-disk instead and prune the persistent connection if
there aren't any.
This commit moves the gossip sync dispatch
such that it is more tightly coupled to the
life cycle of the peer. In testing, I noticed
that the gossip syncer needs to be dispatched
before the first gossip messages come across
the wire.
The prior spawn location in the server happens
after starting all of the peer's goroutines,
which could permit an ordering where the
gossip syncer has not yet been registered.
The new location registers the gossip syncer
within the read handler such that the call is
blocks before any messages are read.
In this commit, we add a quit channel to the AddMsg method of the
msgStream struct. Before this commit, if the queue was full, the
readHandler would block and be unable to exit. We remedy this by
leveraging the existing quit channel of the peer as an additional select
case within the AddMsg method.
In this commit, we thread through the quit of the peer to the execution
of the apply function for a msgStream. This change ensures that if the
target is still processing the message, then the peer is able to exit
cleanly and not block insensately.
In this commit we move the atomic var increment that signals the
consumer goourtine has exited to the top of the method in a defer
statement. This cleans up some duplicate code and also adheres to the
pattern of using defers to signal cleaning up any dependent goroutine
state on exit.
In this commit, we raise the readHandler wait group done into a defer
statement at the top of the method. This fixes an existing but that
would cause the readHandler to declare it had exited, yet possibly still
be waiting on the chan message stream below to exit.
This commit fixes a bug that would cause us to fetch our peer's
ChannelUpdate in some cases, where we really wanted to fetch our own.
The reason this happened was that we passed the peer's pubkey to
fetchLastChanUpdate, making us match on their policy. This would lead to
ChannelUpdates being sent during routing which would have no effect on
the attempted path.
We fix this by always use our own pubkey in fetchLastChanUpdate, and
also uses the common methods within the server to be able to extract the
update even when only one policy is known.
This commit fixes a bug within the peer, where we would always use the
default forwarding policy when adding new links to the switch. Mostly
this wasn't a problem, as we most often are using default values for new
channels, but the min_htlc value is a value that is set by the remote,
not us.
If the remote specified a custom min_htlc during channel creation, we
would still use our DefaultMinHtlc value when first adding the link,
making us try to forward HTLCs that would be rejected by the remote.
We fix this by getting the required min_htlc value from the channel
state machine, and setting this for the link's forwarding policy.
Note that on restarts we will query the database for our latest
ChannelEdgePolicy, and use that to craft the forwardingPolicy. This
means that the value will be set correctly if the policy is found in the
database.
Sometimes when performing an initial sync, the remote
node isn't able to pull messages off the wire because
of long running tasks and queues are saturated. With
a shorter write timeout, we will give up trying to send
messages and teardown the connection, even though the
peer is still active.
This commit adds additional synchronization logic to
WaitForDisconnect, such that it can be spawned before
Start has been executed by the server. Without
modification, the current version will return
immediately since no goroutines will have been
spawned.
To solve this, we modify WaitForDisconnect to block until:
1) the peer is disconnected,
2) the peer is successfully started,
before watching the waitgroup.
In the first case, the waitgroup will block until all
(if any) spawned goroutines have exited. Otherwise, if
the Start is successful, we can switch to watching the
waitgroup, knowing that waitgroup counter is positive.
