We shift the duty of determining the policies to the backward pass as
the forward pass will only be responsible for finding the corrected
receiver amount.
Note that this is not a pure refactor as demonstrated in the test, as
the forward pass doesn't select new policies anymore, which is less
flexible and doesn't lead to the highest possible receiver amount. This
is however neccessary as we otherwise won't be able to compute
forwarding amounts involving inbound fees and this edge case is unlikely
to occur, because we search for a min amount for a route that was most
likely constructed for a larger amount.
Continue adding some complexity behind the BlindedPaymentPathSet. What
we do here is add a new IntroNodeOnlyPath method. The assumption we
make here is: If multiple blinded paths are provided to us in an invoice
but one of those paths only includes an intro node, then there is no
point in looking at any other path since we know that the intro node is
the destination node. So in such a case, we would have discarded any
other path in the `NewBlindedPaymentPathSet` constructor. So then we
would only have a single blinded path made up of an introduction node
only. In this specific case, in the `newRoute` function, no edge passed
to the function would have a blindedPayment associated with it (since
there are no blinded hops in this case). So we will have a case where
`blindedPathSet` passed to `newRoute` is not nil but `blindedPayment` is
nil since nonce was extacted from any edge. If this happens then we can
assume that this is the Intro-Node-Only situation described above. And
so we grabe the associated payment from the path set.
Instead of needing to remember how to handle the FinalCLTV value of a
blinded payment path at various points in the code base, we hide the
logic behind a unified FinalCLTVDelta method on the blinded path.
If multiple blinded paths are provided, they will each have a different
pub key for the destination node. This makes using our existing
pathfinding logic tricky since it depends on having a single destination
node (characterised by a single pub key). We want to re-use this logic.
So what we do is swap out the pub keys of the destinaion hop with a
pseudo target pub key. This will then be used during pathfinding. Later
on once a path is found, we will swap the real destination keys back in
so that onion creation can be done.
We split up the functionality in getRouteUnifiers into checking that all
edges exist via getEdgeUnifiers and then add a backward pass that will
be responsible for determining the sender amount.
We remove the node pub key from the error string, as in route building
this is duplicate info, which can be determined from the input keys,
further it's not available in the backward pass anymore.
We refactor the BuildRoute test to use the require library and add a
test case for a max HTLC violation on the last hop.
Add a `FindBlindedPaths` method to the `ChannelRouter` which will use
the new `findBlindedPaths` function to get a set of candidate blinded
path routes. It then uses mission control to select the best of these
paths.
Note that as of this commit, the MC data we get from these queries won't
mean much since we wont have data about a channel in the direction
towards us. But we do this now in preparation for a future PR which will
start writing mission control success pairs for successful receives from
blinded route paths.
This commit is a large refactor that moves over various responsibilities
from the ChannelRouter to the graph.Builder. These include all graph
related tasks such as:
- graph pruning
- validation of new network updates & persisting new updates
- notifying topology update clients of any changes.
This is a large commit but:
- many of the files are purely moved from `routing` to `graph`
- the business logic put in the graph Builder is copied exactly as is
from the ChannelRouter with one exception:
- The ChannelRouter just needs to be able to call the Builder's
`ApplyChannelUpdate` method. So this is now exported and provided to
the ChannelRouter as a config option.
- The trickiest part was just moving over the test code since quite a
bit had to be duplicated.
In preparation for adding a clean Graph DB interface, we create a
version of FetchLightningNode that doesnt allow a caller to provide in a
transaction.
In this commit, we completely remove the Router's dependence on a Graph
source that requires a `kvdb.RTx`. In so doing, we are more prepared for
a future where the Graph source is backed by different DB structure such
as pure SQL.
The two areas affected here are: the ChannelRouter's graph access that
it uses for pathfinding. And the SessionSource's graph access that it
uses for payments.
The ChannelRouter gets given a Graph and the SessionSource is given a
GraphSessionFactory which it can use to create a new session. Behind the
scenes, this will acquire a kvdb.RTx that will be used for calls to the
Graph's `ForEachNodeChannel` method.
In preparation for structs outside of the `routing` package implementing
this interface, export `routingGraph` and rename it to `Graph` so as to
avoid stuttering.
In this commit, we further reduce the routingGraph interface and this
time we make it more node-agnostic so that it can be backed by any graph
and not one with a concept of "sourceNode".
This commit is purely a refactor. In it, we let the `BlindedEdge` struct
carry a pointer to the `BlindedPayment` that it was derived from. This
is done now because later on in the PR series, we will need more
information about the `BlindedPayment` that an edge was derived from.
Since we now pass in the whole BlindedPayment, we swap out the
`cipherText` member for a `hopIndex` member so that we dont carry around
two sources of truth in the same struct.
In this commit we set up the payment loop context
according to user-provided parameters. The
`cancelable` parameter indicates whether the user
is able to interrupt the payment loop by cancelling
the server stream context. We'll additionally wrap
the context in a deadline if the user provided a
payment timeout.
We remove the timeout channel of the payment_lifecycle.go
and in favor of the deadline context.
Fixes the problem that inbound base fee and fee rate are overwritten
with 0 if they are not specified in PolicyUpdateRequest. This ensures
backward compatibility with older rpc clients that do not yet support
the inbound feature.
In this commit, the tlv extension of a channel update message is parsed.
If an inbound fee schedule is encountered, it is reported in the
graph rpc calls.
In the previous commit the AdditionalEdge interface was introduced
with both of its implementations `BlindedEdge` and `PrivateEdge`.
In both cases where we append a route either by a blinded route
section or private route hints we now use these new types. In
addition the `PayloadSizeFunc` type is introduced in the
`unifiedEdge` struct. This is necessary to have the payload size
function at hand when searching for a route hence not overshooting
the max sphinx package size of 1300 bytes.
In this commit, the FetchChanInfos ChannelGraph method is updated to
take in an optional read transaction for the case where it is called
from within another transaction.
This commit introduces a wrapper function fetchFundingTxWrapper
which calls fetchFundingTx in a goroutine. This is to avoid an issue
with pruned nodes where the router is attempting to stop, but the
prunedBlockDispatcher is waiting to connect to peers that can serve
the block. This can cause the shutdown process to hang until we
connect to a peer that can send us the block.
This commit adds a new interface method `TerminalInfo` and changes its
implementation to return an `*HTLCAttempt` so it includes the route for
a successful payment. Method `GetFailureReason` is now removed as its
returned value can be found in the above method.
This commit removes the method `launchShard` and splits its original
functionality into two steps - first create the attempt, second send the
attempt. This enables us to have finer control over "which error is
returned from which system and how to handle it".
This commit starts handling switch error inside `sendAttempt` when an
error is returned from sending the HTLC. To make sure the updated
`HTLCAttempt` is always returned to the callsite, `handleSwitchErr` now
also returns a `attemptResult`.
This commit removes the unclear abstraction `shardHandler` that's used
in our payment lifecycle. As we'll see in the following commits,
`shardHandler` is an unnecessary layer and everything can be cleanly
managed inside `paymentLifecycle`.
bitromortac