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routing/pathfind: consolidate final vs non-final hop processing

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Conner Fromknecht 2019-12-18 23:55:27 -08:00
parent 495ae8ca42
commit b97adf79a4
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1 changed files with 26 additions and 23 deletions
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49
routing/pathfind.go
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@ -141,18 +141,34 @@ func newRoute(sourceVertex route.Vertex,
// payload for the hop this edge is leading to.
edge := pathEdges[i]
// If this is the last hop, then the hop payload will contain
// the exact amount. In BOLT #4: Onion Routing
// Protocol / "Payload for the Last Node", this is detailed.
amtToForward := finalHop.amt
// We'll calculate the amounts, timelocks, and fees for each hop
// in the route. The base case is the final hop which includes
// their amount and timelocks. These values will accumulate
// contributions from the preceding hops back to the sender as
// we compute the route in reverse.
var (
amtToForward lnwire.MilliSatoshi
fee lnwire.MilliSatoshi
outgoingTimeLock uint32
)
if i == len(pathEdges)-1 {
// If this is the last hop, then the hop payload will
// contain the exact amount. In BOLT #4: Onion Routing
// Protocol / "Payload for the Last Node", this is
// detailed.
amtToForward = finalHop.amt
// Fee is not part of the hop payload, but only used for
// reporting through RPC. Set to zero for the final hop.
fee := lnwire.MilliSatoshi(0)
// Fee is not part of the hop payload, but only used for
// reporting through RPC. Set to zero for the final hop.
fee = lnwire.MilliSatoshi(0)
// If the current hop isn't the last hop, then add enough funds
// to pay for transit over the next link.
if i != len(pathEdges)-1 {
// As this is the last hop, we'll use the specified
// final CLTV delta value instead of the value from the
// last link in the route.
totalTimeLock += uint32(finalHop.cltvDelta)
outgoingTimeLock = currentHeight + uint32(finalHop.cltvDelta)
} else {
// The amount that the current hop needs to forward is
// equal to the incoming amount of the next hop.
amtToForward = nextIncomingAmount
@ -163,20 +179,7 @@ func newRoute(sourceVertex route.Vertex,
// is stored as part of the incoming channel of
// the next hop.
fee = pathEdges[i+1].ComputeFee(amtToForward)
}
// If this is the last hop, then for verification purposes, the
// value of the outgoing time-lock should be _exactly_ the
// absolute time out they'd expect in the HTLC.
var outgoingTimeLock uint32
if i == len(pathEdges)-1 {
// As this is the last hop, we'll use the specified
// final CLTV delta value instead of the value from the
// last link in the route.
totalTimeLock += uint32(finalHop.cltvDelta)
outgoingTimeLock = currentHeight + uint32(finalHop.cltvDelta)
} else {
// Next, increment the total timelock of the entire
// route such that each hops time lock increases as we
// walk backwards in the route, using the delta of the