This commit refactors the semantics of unified policies to unified
edges. The main changes are the following renamings:
* unifiedPolicies -> nodeEdgeUnifier
* unifiedPolicy -> edgeUnifier
* unifiedPolicyEdge -> unifiedEdge
Comments and shortened variable names are changed to reflect the new
semantics.
We encapsulate the capacity inside a unifiedPolicyEdge for later usage.
The meaning of "policy" has changed now, which will be refactored in the
next commmit.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
Pass htlc amount down to the channel so that we don't need to rely
on minHtlc (and pad it when the channel sets a 0 min htlc). Update
test to just check some sane values since we're no longer relying
on minHtlc amount at all.
In this commit we change path finding to no longer consider all channels
between a pair of nodes individually. We assume that nodes forward
non-strict and when we attempt a connection between two nodes, we don't
want to try multiple channels because their policies may not be identical.
Having distinct policies for channel to the same peer is against the
recommendation in the spec, but it happens in the wild. Especially since
we recently changed the default cltv delta value.
What this commit introduces is a unified policy. This can be looked upon
as the greatest common denominator of all policies and should maximize
the probability of getting the payment forwarded.
