Previously, the fuzzer hit a debug panic because we wouldn't include the amount
overpaid to meet a last hop's min_htlc in the total collected paths value. We
now include this value and also penalize hops along the overpaying path to
ensure that it gets deprioritized in path selection.
Previously, we would add a first_hop<>network_node channel that did not have
enough contribution amount to cover the next channel's min htlc plus fees,
because we were storing the next hop as having a path_min that did not include
fees, and would add a connecting first_hop node that did not have enough
contribution amount, leading to a debug panic upon invalid path construction.
See previous commit, but the bug where we would underestimate how much a first
hop candidate needed to be able to relay was also present in blinded paths.
Previously, we would add a candidate hop to the list of potential hops even
though its available contribution wasn't sufficient to meet the next hop's
min_htlc. We'd subsequently build an invalid path using this hop and hit a
debug assertion.
See tests, but the fuzzer found several panics from not fully ignoring these
hints.
We should support these route hints eventually, but it will involve some
reworking of the Path/BlindedTail structs.
MonitorUpdatingPersister is an implementation of Persister that stores
ChannelMonitorUpdates separately from ChannelMonitors. Its RFC is
in #2545, at https://github.com/orgs/lightningdevkit/discussions/2545.
Co-Authored-By: Elias Rohrer <dev@tnull.de>
When using the normal default constructors, we should have some
fee maximum to ensure our default behavior is safe. Here we pick
1% + 50 sats to ensure we're always willing to pay
reasonabl(y high) fees, but not anything too wild.
We setup an MPP scenario with two paths in which we need to overpay to
reach `htlc_minimum_msat`. We then fail the overpaid path and check that
on retry our `max_total_routing_fee_msat` only accounts for the path
fees, but not for the fees overpaid in the first attempt.
We exclude any candidate hops if we find that using them would let the
aggregated path routing fees exceed `max_total_routing_fee_msat`.
Moreover, we return an error if the aggregated fees over all paths of
the selected route would surpass `max_total_routing_fee_msat`.
Currently, users have no means to upper-bound the total fees accruing
when finding a route. Here, we add a corresponding field to
`RouteParameters` which will be used to limit the candidate set during
path finding in the following commits.
`ChannelManager::finish_force_close_channel` exists to do cleanups
which must happen without the `per_peer_state` mutex held. However,
because it lacked lock assertions, several changes snuck in
recently which resulted in it running with peer-state locks held,
risking a deadlock if some HTLCs need to be failed.
We've run into this several times in the wild, likely due to
https://github.com/ElementsProject/lightning/issues/6200 wherein a node on the
path will error with 0x1000 but not provide a channel update (a spec
violation).
Previously, we would blame the inbound edge even though the buggy peer wanted
us to blame the outbound edge. Since this issue seems to be recurring and our
blaming the inbound edge is causing us to punish innocent channels, trust the
peer that the outbound edge is the one to blame.
Previously this value would be incorrectly set to true because we wouldn't
account for blinded hops when determining if we were processing the last hop's
failure packet.
Our ultimate goal with this field is to set
PaymentPathFailed::payment_failed_permanently, so use this name rather than
flipping a bool back and forth across methods.
