`channel_update` messages already have their signatures checked
with the network graph write lock held, so there's no reason to
check the signatures before doing other quicker checks first,
including checking if we're already aware of a newer update for the
channel.
This reduces common-case CPU usage as `channel_update`s are sent
rather liberally over the p2p network to gossip them.
When we have many channels to the same first-hop, many of which do
not have sufficient balance to make the requested payment, but when
some do, instead of simply using the available channel balance we
may switch to MPP, potentially with many, many paths.
Instead, we should seek to use the smallest channel which can
easily handle the requested payment, which we do here by sorting
the first_hops in our router before beginning the graph search.
Note that the "real" fix for this should be to instead decide which
channel to use at HTLC-send time, as most other nodes do during
relay, but this provides a minimal fix without needing to do the
rather-large work of refactoring our HTLC send+relay pipelines.
Issues with overly-aggressive MPP on many channels were reported by
Cash App.
Type aliases are now more robustly being exported in the C bindings
generator, which requires ensuring we don't include some type
aliases which make no sense in bindings.
On connection, if our peer supports gossip queries, and we never
send a `gossip_timestamp_filter`, our peer is supposed to never
send us gossip outside of explicit queries. Thus, we'll end up
always having stale gossip information after the first few
connections we make to peers.
The solution is to send a dummy `gossip_timestamp_filter`
immediately after connecting to peers.
Its somewhat strange to have a trait method which is named after
the intended action, rather than the action that occurred, leaving
it up to the implementor what action they want to take.
If the scoring in the routing benchmark causes us to take a
different path from the original scan, we may end up deciding that
the only path to a node has a too-high total CLTV delta, causing us
to panic in the benchmarking phase.
Here we simply check for that possibility and remove paths that
fail post-scoring.
Filter the route hints in `create_phantom_invoice` based on the
following criteria:
* Only one channel for every counterparty node per phantom
payment-receiving node in the invoice
* Always select the channel with the highest inbound capacity
* For each payment-receiving node, filter out channels with a lower
inbound capacity than the invoice amount, if any channel exists with
enough capacity to cover the invoice amount
* If any public channels exists for a payment-receiving node, push a
single RouteHintHop with the phantom route and let the sender find the
path to the payment-receiving node through the public channels.
Filter the route hints in `create_invoice_from_channelmanager` based on
the following criteria:
* Only one channel per counterparty node
* Always select the channel with the highest inbound capacity
* Filter out channels with a lower inbound capacity than the invoice
amount, if any channel exists with enough capacity to cover the invoice
amount
* If any public channel exists, the invoice route_hints should be empty,
and the sender will need to find the path to the payment-receiving node
by looking at the public channels instead
Previously, if we were offline when a funding transaction was
locked in, and then we came back online, calling
`best_block_updated` once followed by `transactions_confirmed`,
we'd not generate a funding_locked until the next
`best_block_updated`.
We address this by re-calling `best_block_updated` in
`transactions_confirmed`, similar to how `ChannelMonitor` works.
As a part of adding SCID aliases to channels, we now have to accept
otherwise-redundant funding_locked messages which serve only to
update the SCID alias. Previously, we'd failt he channel as such
an update used to be bogus.
This creates an SCID alias for all of our outbound channels, which
we send to our counterparties as a part of the `funding_locked`
message and then recognize in any HTLC forwarding instructions.
Note that we generate an SCID alias for all channels, including
already open ones, even though we currently have no way of
communicating to our peers the SCID alias for already-open
channels.
New `funding_locked` messages can include SCID aliases which our
counterparty will recognize as "ours" for the purposes of relaying
transactions to us. This avoids telling the world about our
on-chain transactions every time we want to receive a payment, and
will allow for receiving payments before the funding transaction
appears on-chain.
Here we store the new SCID aliases and use them in invoices instead
of he "standard" SCIDs.
