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.
In this commit, we extend the graph's FetchChannelEdgesByID and
HasChannelEdge methods to also check the zombie index whenever the edge
to be looked up doesn't exist within the edge index. We do this to
signal to callers that the edge is known, but only as a zombie, and the
only information that we have about the edge are the node public keys of
the two parties involved in the edge.
In the event that an edge does exist within the zombie index, we make
an additional check on edge policies to ensure they are not within the
router's pruning window, indicating that it is a fresh update.
Currently public keys are represented either as a 33-byte array (Vertex) or as a
btcec.PublicKey struct. The latter isn't useable as index into maps and
cannot be used easily in compares. Therefore the 33-byte array
representation is used predominantly throughout the code base.
This commit converts the argument types of source and target nodes for
path finding to Vertex. Path finding executes no crypto operations and
using Vertex simplifies the code.
Additionally, it prepares for the path finding source parameter to be
exposed over rpc in a follow up commit without requiring conversion back
and forth between Vertex and btcec.PublicKey.
This commit allows the execution of QueryRoutes to be controlled using
lists of black-listed edges and nodes. Any path returned will not pass
through the edges and/or nodes on the list.
Since the MaxHTLC field was recently added to the ChannelEdgePolicy struct,
and the Flags field was broken into ChannelFlags and MessageFlags, the
test edge policies should be updated accordingly.
This commit is a step to split the lnwallet package. It puts the Input
interface and implementations in a separate package along with all their
dependencies from lnwallet.
In this commit:
* we partition lnwire.ChanUpdateFlag into two (ChanUpdateChanFlags and
ChanUpdateMsgFlags), from a uint16 to a pair of uint8's
* we rename the ChannelUpdate.Flags to ChannelFlags and add an
additional MessageFlags field, which will be used to indicate the
presence of the optional field HtlcMaximumMsat within the ChannelUpdate.
* we partition ChannelEdgePolicy.Flags into message and channel flags.
This change corresponds to the partitioning of the ChannelUpdate's Flags
field into MessageFlags and ChannelFlags.
Co-authored-by: Johan T. Halseth <johanth@gmail.com>
In this commit we introduce pruning of channel edges instead of channels.
Channel failures apply to a single direction and it is unnecessarily
restricting to prune both directions.
In this commit the dependency of unmarshallRoute on edge policies being
available is removed. Edge policies may be unknown and reported as nil.
SendToRoute does not need the policies, but it does need pubkeys of the
route hops. In this commit, unmarshallRoute is modified so that it
takes the pubkeys from edgeInfo instead of channelEdgePolicy.
In addition to this, the route structure is simplified. No more connection
to the database at that point. Fees are determined based on incoming and
outgoing amounts.
- Extend SendRequest and QueryRoutesRequest protos
- newRoute function takes fee limit and cuts off routes that exceed it
- queryRoutes, payInvoice and sendPayment commands take the feeLimit inputs and pass them down to newRoute
- When no feeLimit is included, don't enforce any feeLimits at all (by setting feeLimit to maxValue)
In this commit, we introduce a new method to the channel router's config
struct: QueryBandwidth. This method allows the channel router to query
for the up-to-date available bandwidth of a particular link. In the case
that this link emanates from/to us, then we can query the switch to see
if the link is active (if not bandwidth is zero), and return the current
best estimate for the available bandwidth of the link. If the link,
isn't one of ours, then we can thread through the total maximal
capacity of the link.
In order to implement this, the missionControl struct will now query the
switch upon creation to obtain a fresh bandwidth snapshot. We take care
to do this in a distinct db transaction in order to now introduced a
circular waiting condition between the mutexes in bolt, and the channel
state machine.
The aim of this change is to reduce the number of unnecessary failures
during HTLC payment routing as we'll now skip any links that are
inactive, or just don't have enough bandwidth for the payment. Nodes
that have several hundred channels (all of which in various states of
activity and available bandwidth) should see a nice gain from this w.r.t
payment latency.
In this commit, we update the TestSendPaymentErrorPathPruning test to
reflect the new behavior w.r.t how we respond to UnknownPeer errors. In
this new test, we expect that we'll find alternative route in light of
us getting an UnknownPeer error "pointing" to our destination node.
In this commit, we modify our path finding algorithm to take an
additional set of edges that are currently not known to us that are
used to temporarily extend our graph with during a payment session.
These edges should assist the sender of a payment in successfully
constructing a path to the destination.
These edges should usually represent private channels, as they are not
publicly advertised to the network for routing.
In this commit, we modify the way we handle FeeInsufficientErrors to
more aggressively route around nodes that repeatedly return the same
error to us. This will ensure we skip older nodes on the network which
are running a buggier older version of lnd. Eventually most nodes will
upgrade to this new version, making this change less needed.
We also update the existing test to properly use a multi-hop route to
ensure that we route around the offending node.
In this commit, we address a number of edge cases that were unaccounted
for when responding to errors that can be sent back due to an HTLC
routing failure. Namely:
* We’ll no longer stop payment attempts if we’re unable to apply a
channel update, instead, we’ll log the error, prune the channel and
continue.
* We’ll no remember which channels were pruned due to insufficient
fee errors. If we ever get a repeat fee error from a channel, then we
prune it. This ensure that we don’t get stuck in a loop due to a node
continually advertising the same fees.
* We also correct an error in which node we’d prune due to a
temporary or permanent node failure. Before this commit, we would prune
the next node, when we should actually be pruning the node that sent us
the error.
Finally, we also add a new test to exercise the fee insufficient error
handling and channel pruning.
Fixes#865.
In this commit, we add a set of new methods to check the freshness of
an edge/node. This will allow callers to skip expensive validation in
the case that the router already knows of an item, or knows of a
fresher version of that time.
A set of tests have been added to ensure basic correctness of these new
methods.
In router_test FindRoutes is passing DefaultFinalCLTVDelta in place
where numPaths is expected. This commit passes a default numPaths for
function calls to FindRoutes so that final cltv delta are correctly
passed.
In this commit, we modify the edgeWeight function that’s used within
the findPath method to weight fees more heavily than the time lock
value at an edge. We do this in order to greedily prefer lower fees
during path finding. This is a simple stop gap in place of more complex
weighting parameters that will be investigated later.
We also modify the edge distance to use an int64 rather than a float.
Finally an additional test has been added in order to excessive this
new change. Before the commit, the test was failing as we preferred the
route with lower total time lock.
Before this commit, we wouldn’t properly set the TotalFees attribute.
As a result, our sorting algorithm at the end to select candidate
routes would simply maintain the time-lock order rather than also sort
by total fees. This commit fixes this issue and also allows the test
added in the prior commit to pass.
In this commit we add a new test to the set of unit tests for the
ChannelRouter: TestRouterChansClosedOfflinePruneGraph. This tests that
if channels are closed while the ChannelRouter is down, then upon
restart the channels are properly recognized as being closed.
