In this commit, we remove the restriction surrounding the largest
invoices that we'll allow a user to create. After #3967 has landed,
users will be able to send in _aggregate_ a payment larger than the
current max HTLC size limit in the network. As a result, we can just
treat that value as the system's MTU, and allow users to request
payments it multiples of that MTU value.
A follow up to this PR at a later time will also allow wumbo _channels_.
However, that requires us to tweak the way we scale CSV values, as post
wumbo, there is no true channel size limit, only the
_local_ limit of a given node. We also need to implement a way for nodes
to signal to other nodes their accepted max channel size.
Modifies the payment session to launch additional pathfinding attempts
for lower amounts. If a single shot payment isn't possible, the goal is
to try to complete the payment using multiple htlcs. In previous
commits, the payment lifecycle has been prepared to deal with
partial-amount routes returned from the payment session. It will query
for additional shards if needed.
Additionally a new rpc payment parameter is added that controls the
maximum number of shards that will be used for the payment.
The default was increased for the main sendpayment RPC in commit
d3fa9767a9729756bab9b4a1121344b265410b1a. This commit sets the
same default for QueryRoutes, routerrpc.SendPayment and
router.EstimateRouteFee.
This commit prepares for more manipulation of custom records. A list of
tlv.Record types is more difficult to use than the more basic
map[uint64][]byte.
Furthermore fields and variables are renamed to make them more
consistent.
In this commitment, we make the `SendToRoute` RPC call consistent with
all the other payment RPCs which will properly adhere to the current max
payment sat limit. This is a prep commit for the future wumbo soft cap
that will eventually land in lnd.
This commit parses mpp_total_amt_msat and mpp_payment_addr from the
SendToRoute rpc and populates an MPP record on the internal hop
reprsentation. When the router goes to encode the onion packet, these
fields will be serialized for the destination. We also populate the mpp
fields when marshalling routes in rpc responses.
Probabilities are no longer returned for querymc calls. To still provide
some insight into the mission control internals, this commit adds a new
rpc that calculates a success probability estimate for a specific node
pair and amount.
With the introduction of the max CLTV limit parameter, nodes are able to
reject HTLCs that exceed it. This should also be applied to path
finding, otherwise HTLCs crafted by the same node that exceed it never
left the switch. This wasn't a big deal since the previous max CLTV
limit was ~5000 blocks. Once it was lowered to 1008, the issue became
more apparent. Therefore, all of our path finding attempts now have a
restriction of said limit in in order to properly carry out HTLCs to the
network.
In order to prevent future unforeseen issues, we are temporarily
disabling the ability to send custom tlv records to the receiver of a
payment. Currently the receiver does not process or expose these
additional fields via rpc or internally, so they are being disabled
until the end-to-end flow is finished and fully validated.
In this commit, we add a new field to the Hop proto to allow callers to
be able to specify TLV records for the SendToRoute call, and also to be
able to display TLV records that were used during regular path finding.
We also update SendPayment to support dest TLV records.
Previously mission control tracked failures on a per node, per channel basis.
This commit changes this to tracking on the level of directed node pairs. The goal
of moving to this coarser-grained level is to reduce the number of required
payment attempts without compromising payment reliability.
Previously every payment had its own local mission control state which
was in effect only for that payment. In this commit most of the local
state is removed and payments all tap into the global mission control
probability estimator.
Furthermore the decay time of pruned edges and nodes is extended, so
that observations about the network can better benefit future payment
processes.
Last, the probability function is transformed from a binary output to a
gradual curve, allowing for a better trade off between candidate routes.
This PR replaces the previously used edge and node ignore lists in path
finding by a probability based system. It modifies path finding so that
it not only compares routes on fee and time lock, but also takes route
success probability into account.
Allowing routes to be compared based on success probability is achieved
by introducing a 'virtual' cost of a payment attempt and using that to
translate probability into another cost factor.
