In this commit, we make our findPath function use an edge's MaxHTLC as
its available bandwidth instead of its Capacity. We do this as it's
possible for the capacity of an edge to not exist when operating as a
light client. For channels that do not support the MaxHTLC optional
field, we'll fall back to using the edge's Capacity.
In this commit, we refactor DeleteChannelEdge to use ChannelIDs rather
than ChannelPoints. We do this as the only use of DeleteChannelEdge is
when we are pruning zombie channels from our graph. When running under a
light client, we are unable to obtain the ChannelPoint of each edge due
to the expensive operations required to do so. As a stop-gap, we'll
resort towards using an edge's ChannelID instead, which is already
gossiped between nodes.
This commit serves as another stop-gap for light clients since they are
unable to obtain the capacity and channel point of graph edges. Since
they're aware of these things for their own channels, they can populate
the information within the graph themselves once each channel has been
successfully added to the graph.
In this commit, we extend the gossiper with support for external callers
to provide optional fields that can serve as useful when processing a
specific network announcement. This will serve useful for light clients,
which are unable to obtain the channel point and capacity for a given
channel, but can provide them manually for their own set of channels.
Since light clients no longer have access to an edge's capacity, they
are unable to validate whether the max HTLC value for an updated edge
policy respects the capacity limit. As a stop-gap, we'll skip this
check.
This serves as a stop-gap for light clients as blocks need to be
downloaded from the P2P network, and even with caches, would be too
costly for them to verify. Doing this has two side effects however:
we'll no longer know of the channel capacity and outpoint, which are
essential for some of lnd's responsibilities.
In this commit, we disable attempting to determine when a channel has
been closed out on-chain whenever AssumeChannelValid is active. Since
the flag indicates that performing this operation is expensive, we do
this as a temporary optimization until we can include proofs of channels
being closed in the gossip protocol.
With this change, the only way for channels being removed from the graph
will be once they're considered zombies: which can happen when both
edges of a channel have their disabled bits set or when both edges
haven't had an update within the past two weeks.
To ensure we don't mark an edge as live again just because an update
with a fresh timestamp was received, we'll ensure that we reject any
new updates for zombie channels if they remain disabled when running
with AssumeChannelValid.
In this commit, we add an additional heuristic when running with
AssumeChannelValid. Since AssumeChannelValid being present assumes that
we're not able to quickly determine whether channels are valid, we also
assume that any channels with the disabled bit set on both sides are
considered zombie. This should be relatively safe to do, since the
disabled bits are usually set when the channel is closed on-chain. In
the case that they aren't, we'll have to wait until both edges haven't
had a new update within two weeks to prune them.
We do this to ensure we don't prune too aggressively, as it's possible
that we've only received the channel announcement for a channel, but not
its accompanying channel updates.
This new version of neutrino includes a number of fixes to the query
functionality of neutrino, stuck syncing issues, and peer connection
handling and banning.
This enables users to specify an external API for fee estimation.
The API is expected to return fees in the JSON format:
`{
fee_by_block_target: {
a: x,
b: y,
...
c: z
}
}`
where a, b, c are block targets and x, y, z are fees in sat/kb.
Note that a, b, c need not be contiguous.
In this commit, we add a new interface which will allow callers to drop
in an arbitrary Web API for fee estimation with an arbitrary
request/response schema.
Co-authored-by: Valentine Wallace <vwallace@protonmail.com>
