15838907453

Committed 24 Jun 2025 01:26AM UTC coverage: 57.079% (-11.1%) from 68.172%

Build # 15838907453

Build Type

Pull #9982

github

Committed by

web-flow

Commit Message

Merge e42780be2 into 45c15646c

Pull Request Pull Request #9982: lnwire+lnwallet: add LocalNonces field for splice nonce coordination w/ taproot channels

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77.25

/routing/unified_edges.go

package routing

import (
        "math"

        "github.com/btcsuite/btcd/btcutil"
        graphdb "github.com/lightningnetwork/lnd/graph/db"
        "github.com/lightningnetwork/lnd/graph/db/models"
        "github.com/lightningnetwork/lnd/lnwire"
        "github.com/lightningnetwork/lnd/routing/route"
)

// nodeEdgeUnifier holds all edge unifiers for connections towards a node.
type nodeEdgeUnifier struct {
        // edgeUnifiers contains an edge unifier for every from node.
        edgeUnifiers map[route.Vertex]*edgeUnifier

        // sourceNode is the sender of a payment. The rules to pick the final
        // policy are different for local channels.
        sourceNode route.Vertex

        // toNode is the node for which the edge unifiers are instantiated.
        toNode route.Vertex

        // useInboundFees indicates whether to take inbound fees into account.
        useInboundFees bool

        // outChanRestr is an optional outgoing channel restriction for the
        // local channel to use.
        outChanRestr map[uint64]struct{}
}

// newNodeEdgeUnifier instantiates a new nodeEdgeUnifier object. Channel
// policies can be added to this object.
func newNodeEdgeUnifier(sourceNode, toNode route.Vertex, useInboundFees bool,
        outChanRestr map[uint64]struct{}) *nodeEdgeUnifier {

        return &nodeEdgeUnifier{
                edgeUnifiers:   make(map[route.Vertex]*edgeUnifier),
                toNode:         toNode,
                useInboundFees: useInboundFees,
                sourceNode:     sourceNode,
                outChanRestr:   outChanRestr,
        }
}

// addPolicy adds a single channel policy. Capacity may be zero if unknown
// (light clients). We expect a non-nil payload size function and will request a
// graceful shutdown if it is not provided as this indicates that edges are
// incorrectly specified.
func (u *nodeEdgeUnifier) addPolicy(fromNode route.Vertex,
        edge *models.CachedEdgePolicy, inboundFee models.InboundFee,
        capacity btcutil.Amount, hopPayloadSizeFn PayloadSizeFunc,
        blindedPayment *BlindedPayment) {

        localChan := fromNode == u.sourceNode

        // Skip channels if there is an outgoing channel restriction.
        if localChan && u.outChanRestr != nil {
                if _, ok := u.outChanRestr[edge.ChannelID]; !ok {
                        log.Debugf("Skipped adding policy for restricted edge "+
                                "%v", edge.ChannelID)

                        return
                }
        }

        // Update the edgeUnifiers map.
        unifier, ok := u.edgeUnifiers[fromNode]
        if !ok {
                unifier = &edgeUnifier{
                        localChan: localChan,
                }
                u.edgeUnifiers[fromNode] = unifier
        }

        // In case no payload size function was provided a graceful shutdown
        // is requested, because this function is not used as intended.
        if hopPayloadSizeFn == nil {
                log.Criticalf("No payloadsize function was provided for the "+
                        "edge (chanid=%v) when adding it to the edge unifier "+
                        "of node: %v", edge.ChannelID, fromNode)

                return
        }

        // Zero inbound fee for exit hops.
        if !u.useInboundFees {
                inboundFee = models.InboundFee{}
        }

        unifier.edges = append(unifier.edges, newUnifiedEdge(
                edge, capacity, inboundFee, hopPayloadSizeFn, blindedPayment,
        ))
}

// addGraphPolicies adds all policies that are known for the toNode in the
// graph.
func (u *nodeEdgeUnifier) addGraphPolicies(g Graph) error {
        cb := func(channel *graphdb.DirectedChannel) error {
                // If there is no edge policy for this candidate node, skip.
                // Note that we are searching backwards so this node would have
                // come prior to the pivot node in the route.
                if channel.InPolicy == nil {
                        log.Debugf("Skipped adding edge %v due to nil policy",
                                channel.ChannelID)

                        return nil
                }

                // Add this policy to the corresponding edgeUnifier. We default
                // to the clear hop payload size function because
                // `addGraphPolicies` is only used for cleartext intermediate
                // hops in a route.
                inboundFee := models.NewInboundFeeFromWire(
                        channel.InboundFee,
                )

                u.addPolicy(
                        channel.OtherNode, channel.InPolicy, inboundFee,
                        channel.Capacity, defaultHopPayloadSize, nil,
                )

                return nil
        }

        // Iterate over all channels of the to node.
        return g.ForEachNodeDirectedChannel(u.toNode, cb)
}

// unifiedEdge is the individual channel data that is kept inside an edgeUnifier
// object.
type unifiedEdge struct {
        policy      *models.CachedEdgePolicy
        capacity    btcutil.Amount
        inboundFees models.InboundFee

        // hopPayloadSize supplies an edge with the ability to calculate the
        // exact payload size if this edge would be included in a route. This
        // is needed because hops of a blinded path differ in their payload
        // structure compared to cleartext hops.
        hopPayloadSizeFn PayloadSizeFunc

        // blindedPayment if set, is the BlindedPayment that this edge was
        // derived from originally.
        blindedPayment *BlindedPayment
}

// newUnifiedEdge constructs a new unifiedEdge.
func newUnifiedEdge(policy *models.CachedEdgePolicy, capacity btcutil.Amount,
        inboundFees models.InboundFee, hopPayloadSizeFn PayloadSizeFunc,
        blindedPayment *BlindedPayment) *unifiedEdge {

        return &unifiedEdge{
                policy:           policy,
                capacity:         capacity,
                inboundFees:      inboundFees,
                hopPayloadSizeFn: hopPayloadSizeFn,
                blindedPayment:   blindedPayment,
        }
}

// amtInRange checks whether an amount falls within the valid range for a
// channel.
func (u *unifiedEdge) amtInRange(amt lnwire.MilliSatoshi) bool {
        // If the capacity is available (non-light clients), skip channels that
        // are too small.
        if u.capacity > 0 &&
                amt > lnwire.NewMSatFromSatoshis(u.capacity) {

                log.Tracef("Not enough capacity: amt=%v, capacity=%v",
                        amt, u.capacity)
                return false
        }

        // Skip channels for which this htlc is too large.
        if u.policy.MessageFlags.HasMaxHtlc() &&
                amt > u.policy.MaxHTLC {

                log.Tracef("Exceeds policy's MaxHTLC: amt=%v, MaxHTLC=%v",
                        amt, u.policy.MaxHTLC)
                return false
        }

        // Skip channels for which this htlc is too small.
        if amt < u.policy.MinHTLC {
                log.Tracef("below policy's MinHTLC: amt=%v, MinHTLC=%v",
                        amt, u.policy.MinHTLC)
                return false
        }

        return true
}

// edgeUnifier is an object that covers all channels between a pair of nodes.
type edgeUnifier struct {
        edges     []*unifiedEdge
        localChan bool
}

// getEdge returns the optimal unified edge to use for this connection given a
// specific amount to send. It differentiates between local and network
// channels.
func (u *edgeUnifier) getEdge(netAmtReceived lnwire.MilliSatoshi,
        bandwidthHints bandwidthHints,
        nextOutFee lnwire.MilliSatoshi) *unifiedEdge {

        if u.localChan {
                return u.getEdgeLocal(
                        netAmtReceived, bandwidthHints, nextOutFee,
                )
        }

        return u.getEdgeNetwork(netAmtReceived, nextOutFee)
}

// calcCappedInboundFee calculates the inbound fee for a channel, taking into
// account the total node fee for the "to" node.
func calcCappedInboundFee(edge *unifiedEdge, amt lnwire.MilliSatoshi,
        nextOutFee lnwire.MilliSatoshi) int64 {

        // Calculate the inbound fee charged for the amount that passes over the
        // channel.
        inboundFee := edge.inboundFees.CalcFee(amt)

        // Take into account that the total node fee cannot be negative.
        if inboundFee < -int64(nextOutFee) {
                inboundFee = -int64(nextOutFee)
        }

        return inboundFee
}

// getEdgeLocal returns the optimal unified edge to use for this local
// connection given a specific amount to send.
func (u *edgeUnifier) getEdgeLocal(netAmtReceived lnwire.MilliSatoshi,
        bandwidthHints bandwidthHints,
        nextOutFee lnwire.MilliSatoshi) *unifiedEdge {

        var (
                bestEdge     *unifiedEdge
                maxBandwidth lnwire.MilliSatoshi
        )

        for _, edge := range u.edges {
                // Calculate the inbound fee charged at the receiving node.
                inboundFee := calcCappedInboundFee(
                        edge, netAmtReceived, nextOutFee,
                )

                // Add inbound fee to get to the amount that is sent over the
                // local channel.
                amt := netAmtReceived + lnwire.MilliSatoshi(inboundFee)

                // Check valid amount range for the channel. We skip this test
                // for payments with custom HTLC data, as the amount sent on
                // the BTC layer may differ from the amount that is actually
                // forwarded in custom channels.
                if bandwidthHints.firstHopCustomBlob().IsNone() &&
                        !edge.amtInRange(amt) {

                        log.Debugf("Amount %v not in range for edge %v",
                                netAmtReceived, edge.policy.ChannelID)

                        continue
                }

                // For local channels, there is no fee to pay or an extra time
                // lock. We only consider the currently available bandwidth for
                // channel selection. The disabled flag is ignored for local
                // channels.

                // Retrieve bandwidth for this local channel. If not
                // available, assume this channel has enough bandwidth.
                //
                // TODO(joostjager): Possibly change to skipping this
                // channel. The bandwidth hint is expected to be
                // available.
                bandwidth, ok := bandwidthHints.availableChanBandwidth(
                        edge.policy.ChannelID, amt,
                )
                if !ok {
                        log.Debugf("Cannot get bandwidth for edge %v, use max "+
                                "instead", edge.policy.ChannelID)
                        bandwidth = lnwire.MaxMilliSatoshi
                }

                // TODO(yy): if the above `!ok` is chosen, we'd have
                // `bandwidth` to be the max value, which will end up having
                // the `maxBandwidth` to be have the largest value and this
                // edge will be the chosen one. This is wrong in two ways,
                // 1. we need to understand why `availableChanBandwidth` cannot
                // find bandwidth for this edge as something is wrong with this
                // channel, and,
                // 2. this edge is likely NOT the local channel with the
                // highest available bandwidth.
                //
                // Skip channels that can't carry the payment.
                if amt > bandwidth {
                        log.Debugf("Skipped edge %v: not enough bandwidth, "+
                                "bandwidth=%v, amt=%v", edge.policy.ChannelID,
                                bandwidth, amt)

                        continue
                }

                // We pick the local channel with the highest available
                // bandwidth, to maximize the success probability. It can be
                // that the channel state changes between querying the bandwidth
                // hints and sending out the htlc.
                if bandwidth < maxBandwidth {
                        log.Debugf("Skipped edge %v: not max bandwidth, "+
                                "bandwidth=%v, maxBandwidth=%v",
                                edge.policy.ChannelID, bandwidth, maxBandwidth)

                        continue
                }
                maxBandwidth = bandwidth

                // Update best edge.
                bestEdge = newUnifiedEdge(
                        edge.policy, edge.capacity, edge.inboundFees,
                        edge.hopPayloadSizeFn, edge.blindedPayment,
                )
        }

        return bestEdge
}

// getEdgeNetwork returns the optimal unified edge to use for this connection
// given a specific amount to send. The goal is to return a unified edge with a
// policy that maximizes the probability of a successful forward in a non-strict
// forwarding context.
func (u *edgeUnifier) getEdgeNetwork(netAmtReceived lnwire.MilliSatoshi,
        nextOutFee lnwire.MilliSatoshi) *unifiedEdge {

        var (
                bestPolicy       *unifiedEdge
                maxFee           int64 = math.MinInt64
                maxTimelock      uint16
                maxCapMsat       lnwire.MilliSatoshi
                hopPayloadSizeFn PayloadSizeFunc
        )

        for _, edge := range u.edges {
                // Calculate the inbound fee charged at the receiving node.
                inboundFee := calcCappedInboundFee(
                        edge, netAmtReceived, nextOutFee,
                )

                // Add inbound fee to get to the amount that is sent over the
                // channel.
                amt := netAmtReceived + lnwire.MilliSatoshi(inboundFee)

                // Check valid amount range for the channel.
                if !edge.amtInRange(amt) {
                        log.Debugf("Amount %v not in range for edge %v",
                                amt, edge.policy.ChannelID)
                        continue
                }

                // For network channels, skip the disabled ones.
                if edge.policy.IsDisabled() {
                        log.Debugf("Skipped edge %v due to it being disabled",
                                edge.policy.ChannelID)
                        continue
                }

                // Track the maximal capacity for usable channels. If we don't
                // know the capacity, we fall back to MaxHTLC.
                capMsat := lnwire.NewMSatFromSatoshis(edge.capacity)
                if capMsat == 0 && edge.policy.MessageFlags.HasMaxHtlc() {
                        log.Tracef("No capacity available for channel %v, "+
                                "using MaxHtlcMsat (%v) as a fallback.",
                                edge.policy.ChannelID, edge.policy.MaxHTLC)

                        capMsat = edge.policy.MaxHTLC
                }
                maxCapMsat = max(capMsat, maxCapMsat)

                // Track the maximum time lock of all channels that are
                // candidate for non-strict forwarding at the routing node.
                maxTimelock = max(maxTimelock, edge.policy.TimeLockDelta)

                outboundFee := int64(edge.policy.ComputeFee(amt))
                fee := outboundFee + inboundFee

                // Use the policy that results in the highest fee for this
                // specific amount.
                if fee < maxFee {
                        log.Debugf("Skipped edge %v due to it produces less "+
                                "fee: fee=%v, maxFee=%v",
                                edge.policy.ChannelID, fee, maxFee)

                        continue
                }
                maxFee = fee

                bestPolicy = newUnifiedEdge(
                        edge.policy, 0, edge.inboundFees, nil,
                        edge.blindedPayment,
                )

                // The payload size function for edges to a connected peer is
                // always the same hence there is not need to find the maximum.
                // This also counts for blinded edges where we only have one
                // edge to a blinded peer.
                hopPayloadSizeFn = edge.hopPayloadSizeFn
        }

        // Return early if no channel matches.
        if bestPolicy == nil {
                return nil
        }

        // We have already picked the highest fee that could be required for
        // non-strict forwarding. To also cover the case where a lower fee
        // channel requires a longer time lock, we modify the policy by setting
        // the maximum encountered time lock. Note that this results in a
        // synthetic policy that is not actually present on the routing node.
        //
        // The reason we do this, is that we try to maximize the chance that we
        // get forwarded. Because we penalize pair-wise, there won't be a second
        // chance for this node pair. But this is all only needed for nodes that
        // have distinct policies for channels to the same peer.
        policyCopy := *bestPolicy.policy
        policyCopy.TimeLockDelta = maxTimelock
        modifiedEdge := newUnifiedEdge(
                &policyCopy, maxCapMsat.ToSatoshis(), bestPolicy.inboundFees,
                hopPayloadSizeFn, bestPolicy.blindedPayment,
        )

        return modifiedEdge
}

// minAmt returns the minimum amount that can be forwarded on this connection.
func (u *edgeUnifier) minAmt() lnwire.MilliSatoshi {
        minAmount := lnwire.MaxMilliSatoshi
        for _, edge := range u.edges {
                minAmount = min(minAmount, edge.policy.MinHTLC)
        }

        return minAmount
}

1	package routing
2
3	import (
4	"math"
5
6	"github.com/btcsuite/btcd/btcutil"
7	graphdb "github.com/lightningnetwork/lnd/graph/db"
8	"github.com/lightningnetwork/lnd/graph/db/models"
9	"github.com/lightningnetwork/lnd/lnwire"
10	"github.com/lightningnetwork/lnd/routing/route"
11	)
12
13	// nodeEdgeUnifier holds all edge unifiers for connections towards a node.
14	type nodeEdgeUnifier struct {
15	// edgeUnifiers contains an edge unifier for every from node.
16	edgeUnifiers map[route.Vertex]*edgeUnifier
17
18	// sourceNode is the sender of a payment. The rules to pick the final
19	// policy are different for local channels.
20	sourceNode route.Vertex
21
22	// toNode is the node for which the edge unifiers are instantiated.
23	toNode route.Vertex
24
25	// useInboundFees indicates whether to take inbound fees into account.
26	useInboundFees bool
27
28	// outChanRestr is an optional outgoing channel restriction for the
29	// local channel to use.
30	outChanRestr map[uint64]struct{}
31	}
32
33	// newNodeEdgeUnifier instantiates a new nodeEdgeUnifier object. Channel
34	// policies can be added to this object.
35	func newNodeEdgeUnifier(sourceNode, toNode route.Vertex, useInboundFees bool,
36	outChanRestr map[uint64]struct{}) *nodeEdgeUnifier {	1✔
37		1✔
38	return &nodeEdgeUnifier{	1✔
39	edgeUnifiers: make(map[route.Vertex]*edgeUnifier),	1✔
40	toNode: toNode,	1✔
41	useInboundFees: useInboundFees,	1✔
42	sourceNode: sourceNode,	1✔
43	outChanRestr: outChanRestr,	1✔
44	}	1✔
45	}	1✔
46
47	// addPolicy adds a single channel policy. Capacity may be zero if unknown
48	// (light clients). We expect a non-nil payload size function and will request a
49	// graceful shutdown if it is not provided as this indicates that edges are
50	// incorrectly specified.
51	func (u *nodeEdgeUnifier) addPolicy(fromNode route.Vertex,
52	edge *models.CachedEdgePolicy, inboundFee models.InboundFee,
53	capacity btcutil.Amount, hopPayloadSizeFn PayloadSizeFunc,
54	blindedPayment *BlindedPayment) {	1✔
55		1✔
56	localChan := fromNode == u.sourceNode	1✔
57		1✔
58	// Skip channels if there is an outgoing channel restriction.	1✔
59	if localChan && u.outChanRestr != nil {	1✔
UNCOV 60	if _, ok := u.outChanRestr[edge.ChannelID]; !ok {	×
UNCOV 61	log.Debugf("Skipped adding policy for restricted edge "+	×
UNCOV 62	"%v", edge.ChannelID)	×
UNCOV 63		×
UNCOV 64	return	×
UNCOV 65	}	×
66	}
67
68	// Update the edgeUnifiers map.
69	unifier, ok := u.edgeUnifiers[fromNode]	1✔
70	if !ok {	2✔
71	unifier = &edgeUnifier{	1✔
72	localChan: localChan,	1✔
73	}	1✔
74	u.edgeUnifiers[fromNode] = unifier	1✔
75	}	1✔
76
77	// In case no payload size function was provided a graceful shutdown
78	// is requested, because this function is not used as intended.
79	if hopPayloadSizeFn == nil {	1✔
80	log.Criticalf("No payloadsize function was provided for the "+	×
81	"edge (chanid=%v) when adding it to the edge unifier "+	×
82	"of node: %v", edge.ChannelID, fromNode)	×
83		×
84	return	×
85	}	×
86
87	// Zero inbound fee for exit hops.
88	if !u.useInboundFees {	2✔
89	inboundFee = models.InboundFee{}	1✔
90	}	1✔
91
92	unifier.edges = append(unifier.edges, newUnifiedEdge(	1✔
93	edge, capacity, inboundFee, hopPayloadSizeFn, blindedPayment,	1✔
94	))	1✔
95	}
96
97	// addGraphPolicies adds all policies that are known for the toNode in the
98	// graph.
99	func (u *nodeEdgeUnifier) addGraphPolicies(g Graph) error {	1✔
100	cb := func(channel *graphdb.DirectedChannel) error {	2✔
101	// If there is no edge policy for this candidate node, skip.	1✔
102	// Note that we are searching backwards so this node would have	1✔
103	// come prior to the pivot node in the route.	1✔
104	if channel.InPolicy == nil {	1✔
105	log.Debugf("Skipped adding edge %v due to nil policy",	×
106	channel.ChannelID)	×
107		×
108	return nil	×
109	}	×
110
111	// Add this policy to the corresponding edgeUnifier. We default
112	// to the clear hop payload size function because
113	// `addGraphPolicies` is only used for cleartext intermediate
114	// hops in a route.
115	inboundFee := models.NewInboundFeeFromWire(	1✔
116	channel.InboundFee,	1✔
117	)	1✔
118		1✔
119	u.addPolicy(	1✔
120	channel.OtherNode, channel.InPolicy, inboundFee,	1✔
121	channel.Capacity, defaultHopPayloadSize, nil,	1✔
122	)	1✔
123		1✔
124	return nil	1✔
125	}
126
127	// Iterate over all channels of the to node.
128	return g.ForEachNodeDirectedChannel(u.toNode, cb)	1✔
129	}
130
131	// unifiedEdge is the individual channel data that is kept inside an edgeUnifier
132	// object.
133	type unifiedEdge struct {
134	policy *models.CachedEdgePolicy
135	capacity btcutil.Amount
136	inboundFees models.InboundFee
137
138	// hopPayloadSize supplies an edge with the ability to calculate the
139	// exact payload size if this edge would be included in a route. This
140	// is needed because hops of a blinded path differ in their payload
141	// structure compared to cleartext hops.
142	hopPayloadSizeFn PayloadSizeFunc
143
144	// blindedPayment if set, is the BlindedPayment that this edge was
145	// derived from originally.
146	blindedPayment *BlindedPayment
147	}
148
149	// newUnifiedEdge constructs a new unifiedEdge.
150	func newUnifiedEdge(policy *models.CachedEdgePolicy, capacity btcutil.Amount,
151	inboundFees models.InboundFee, hopPayloadSizeFn PayloadSizeFunc,
152	blindedPayment BlindedPayment) unifiedEdge {	1✔
153		1✔
154	return &unifiedEdge{	1✔
155	policy: policy,	1✔
156	capacity: capacity,	1✔
157	inboundFees: inboundFees,	1✔
158	hopPayloadSizeFn: hopPayloadSizeFn,	1✔
159	blindedPayment: blindedPayment,	1✔
160	}	1✔
161	}	1✔
162
163	// amtInRange checks whether an amount falls within the valid range for a
164	// channel.
165	func (u *unifiedEdge) amtInRange(amt lnwire.MilliSatoshi) bool {	1✔
166	// If the capacity is available (non-light clients), skip channels that	1✔
167	// are too small.	1✔
168	if u.capacity > 0 &&	1✔
169	amt > lnwire.NewMSatFromSatoshis(u.capacity) {	1✔
UNCOV 170		×
UNCOV 171	log.Tracef("Not enough capacity: amt=%v, capacity=%v",	×
UNCOV 172	amt, u.capacity)	×
UNCOV 173	return false	×
UNCOV 174	}	×
175
176	// Skip channels for which this htlc is too large.
177	if u.policy.MessageFlags.HasMaxHtlc() &&	1✔
178	amt > u.policy.MaxHTLC {	2✔
179		1✔
180	log.Tracef("Exceeds policy's MaxHTLC: amt=%v, MaxHTLC=%v",	1✔
181	amt, u.policy.MaxHTLC)	1✔
182	return false	1✔
183	}	1✔
184
185	// Skip channels for which this htlc is too small.
186	if amt < u.policy.MinHTLC {	2✔
187	log.Tracef("below policy's MinHTLC: amt=%v, MinHTLC=%v",	1✔
188	amt, u.policy.MinHTLC)	1✔
189	return false	1✔
190	}	1✔
191
192	return true	1✔
193	}
194
195	// edgeUnifier is an object that covers all channels between a pair of nodes.
196	type edgeUnifier struct {
197	edges []*unifiedEdge
198	localChan bool
199	}
200
201	// getEdge returns the optimal unified edge to use for this connection given a
202	// specific amount to send. It differentiates between local and network
203	// channels.
204	func (u *edgeUnifier) getEdge(netAmtReceived lnwire.MilliSatoshi,
205	bandwidthHints bandwidthHints,
206	nextOutFee lnwire.MilliSatoshi) *unifiedEdge {	1✔
207		1✔
208	if u.localChan {	2✔
209	return u.getEdgeLocal(	1✔
210	netAmtReceived, bandwidthHints, nextOutFee,	1✔
211	)	1✔
212	}	1✔
213
214	return u.getEdgeNetwork(netAmtReceived, nextOutFee)	1✔
215	}
216
217	// calcCappedInboundFee calculates the inbound fee for a channel, taking into
218	// account the total node fee for the "to" node.
219	func calcCappedInboundFee(edge *unifiedEdge, amt lnwire.MilliSatoshi,
220	nextOutFee lnwire.MilliSatoshi) int64 {	1✔
221		1✔
222	// Calculate the inbound fee charged for the amount that passes over the	1✔
223	// channel.	1✔
224	inboundFee := edge.inboundFees.CalcFee(amt)	1✔
225		1✔
226	// Take into account that the total node fee cannot be negative.	1✔
227	if inboundFee < -int64(nextOutFee) {	1✔
UNCOV 228	inboundFee = -int64(nextOutFee)	×
UNCOV 229	}	×
230
231	return inboundFee	1✔
232	}
233
234	// getEdgeLocal returns the optimal unified edge to use for this local
235	// connection given a specific amount to send.
236	func (u *edgeUnifier) getEdgeLocal(netAmtReceived lnwire.MilliSatoshi,
237	bandwidthHints bandwidthHints,
238	nextOutFee lnwire.MilliSatoshi) *unifiedEdge {	1✔
239		1✔
240	var (	1✔
241	bestEdge *unifiedEdge	1✔
242	maxBandwidth lnwire.MilliSatoshi	1✔
243	)	1✔
244		1✔
245	for _, edge := range u.edges {	2✔
246	// Calculate the inbound fee charged at the receiving node.	1✔
247	inboundFee := calcCappedInboundFee(	1✔
248	edge, netAmtReceived, nextOutFee,	1✔
249	)	1✔
250		1✔
251	// Add inbound fee to get to the amount that is sent over the	1✔
252	// local channel.	1✔
253	amt := netAmtReceived + lnwire.MilliSatoshi(inboundFee)	1✔
254		1✔
255	// Check valid amount range for the channel. We skip this test	1✔
256	// for payments with custom HTLC data, as the amount sent on	1✔
257	// the BTC layer may differ from the amount that is actually	1✔
258	// forwarded in custom channels.	1✔
259	if bandwidthHints.firstHopCustomBlob().IsNone() &&	1✔
260	!edge.amtInRange(amt) {	1✔
UNCOV 261		×
UNCOV 262	log.Debugf("Amount %v not in range for edge %v",	×
UNCOV 263	netAmtReceived, edge.policy.ChannelID)	×
UNCOV 264		×
UNCOV 265	continue	×
266	}
267
268	// For local channels, there is no fee to pay or an extra time
269	// lock. We only consider the currently available bandwidth for
270	// channel selection. The disabled flag is ignored for local
271	// channels.
272
273	// Retrieve bandwidth for this local channel. If not
274	// available, assume this channel has enough bandwidth.
275	//
276	// TODO(joostjager): Possibly change to skipping this
277	// channel. The bandwidth hint is expected to be
278	// available.
279	bandwidth, ok := bandwidthHints.availableChanBandwidth(	1✔
280	edge.policy.ChannelID, amt,	1✔
281	)	1✔
282	if !ok {	1✔
UNCOV 283	log.Debugf("Cannot get bandwidth for edge %v, use max "+	×
UNCOV 284	"instead", edge.policy.ChannelID)	×
UNCOV 285	bandwidth = lnwire.MaxMilliSatoshi	×
UNCOV 286	}	×
287
288	// TODO(yy): if the above `!ok` is chosen, we'd have
289	// `bandwidth` to be the max value, which will end up having
290	// the `maxBandwidth` to be have the largest value and this
291	// edge will be the chosen one. This is wrong in two ways,
292	// 1. we need to understand why `availableChanBandwidth` cannot
293	// find bandwidth for this edge as something is wrong with this
294	// channel, and,
295	// 2. this edge is likely NOT the local channel with the
296	// highest available bandwidth.
297	//
298	// Skip channels that can't carry the payment.
299	if amt > bandwidth {	2✔
300	log.Debugf("Skipped edge %v: not enough bandwidth, "+	1✔
301	"bandwidth=%v, amt=%v", edge.policy.ChannelID,	1✔
302	bandwidth, amt)	1✔
303		1✔
304	continue	1✔
305	}
306
307	// We pick the local channel with the highest available
308	// bandwidth, to maximize the success probability. It can be
309	// that the channel state changes between querying the bandwidth
310	// hints and sending out the htlc.
311	if bandwidth < maxBandwidth {	1✔
UNCOV 312	log.Debugf("Skipped edge %v: not max bandwidth, "+	×
UNCOV 313	"bandwidth=%v, maxBandwidth=%v",	×
UNCOV 314	edge.policy.ChannelID, bandwidth, maxBandwidth)	×
UNCOV 315		×
UNCOV 316	continue	×
317	}
318	maxBandwidth = bandwidth	1✔
319		1✔
320	// Update best edge.	1✔
321	bestEdge = newUnifiedEdge(	1✔
322	edge.policy, edge.capacity, edge.inboundFees,	1✔
323	edge.hopPayloadSizeFn, edge.blindedPayment,	1✔
324	)	1✔
325	}
326
327	return bestEdge	1✔
328	}
329
330	// getEdgeNetwork returns the optimal unified edge to use for this connection
331	// given a specific amount to send. The goal is to return a unified edge with a
332	// policy that maximizes the probability of a successful forward in a non-strict
333	// forwarding context.
334	func (u *edgeUnifier) getEdgeNetwork(netAmtReceived lnwire.MilliSatoshi,
335	nextOutFee lnwire.MilliSatoshi) *unifiedEdge {	1✔
336		1✔
337	var (	1✔
338	bestPolicy *unifiedEdge	1✔
339	maxFee int64 = math.MinInt64	1✔
340	maxTimelock uint16	1✔
341	maxCapMsat lnwire.MilliSatoshi	1✔
342	hopPayloadSizeFn PayloadSizeFunc	1✔
343	)	1✔
344		1✔
345	for _, edge := range u.edges {	2✔
346	// Calculate the inbound fee charged at the receiving node.	1✔
347	inboundFee := calcCappedInboundFee(	1✔
348	edge, netAmtReceived, nextOutFee,	1✔
349	)	1✔
350		1✔
351	// Add inbound fee to get to the amount that is sent over the	1✔
352	// channel.	1✔
353	amt := netAmtReceived + lnwire.MilliSatoshi(inboundFee)	1✔
354		1✔
355	// Check valid amount range for the channel.	1✔
356	if !edge.amtInRange(amt) {	2✔
357	log.Debugf("Amount %v not in range for edge %v",	1✔
358	amt, edge.policy.ChannelID)	1✔
359	continue	1✔
360	}
361
362	// For network channels, skip the disabled ones.
363	if edge.policy.IsDisabled() {	1✔
UNCOV 364	log.Debugf("Skipped edge %v due to it being disabled",	×
UNCOV 365	edge.policy.ChannelID)	×
UNCOV 366	continue	×
367	}
368
369	// Track the maximal capacity for usable channels. If we don't
370	// know the capacity, we fall back to MaxHTLC.
371	capMsat := lnwire.NewMSatFromSatoshis(edge.capacity)	1✔
372	if capMsat == 0 && edge.policy.MessageFlags.HasMaxHtlc() {	1✔
UNCOV 373	log.Tracef("No capacity available for channel %v, "+	×
UNCOV 374	"using MaxHtlcMsat (%v) as a fallback.",	×
UNCOV 375	edge.policy.ChannelID, edge.policy.MaxHTLC)	×
UNCOV 376		×
UNCOV 377	capMsat = edge.policy.MaxHTLC	×
UNCOV 378	}	×
379	maxCapMsat = max(capMsat, maxCapMsat)	1✔
380		1✔
381	// Track the maximum time lock of all channels that are	1✔
382	// candidate for non-strict forwarding at the routing node.	1✔
383	maxTimelock = max(maxTimelock, edge.policy.TimeLockDelta)	1✔
384		1✔
385	outboundFee := int64(edge.policy.ComputeFee(amt))	1✔
386	fee := outboundFee + inboundFee	1✔
387		1✔
388	// Use the policy that results in the highest fee for this	1✔
389	// specific amount.	1✔
390	if fee < maxFee {	1✔
UNCOV 391	log.Debugf("Skipped edge %v due to it produces less "+	×
UNCOV 392	"fee: fee=%v, maxFee=%v",	×
UNCOV 393	edge.policy.ChannelID, fee, maxFee)	×
UNCOV 394		×
UNCOV 395	continue	×
396	}
397	maxFee = fee	1✔
398		1✔
399	bestPolicy = newUnifiedEdge(	1✔
400	edge.policy, 0, edge.inboundFees, nil,	1✔
401	edge.blindedPayment,	1✔
402	)	1✔
403		1✔
404	// The payload size function for edges to a connected peer is	1✔
405	// always the same hence there is not need to find the maximum.	1✔
406	// This also counts for blinded edges where we only have one	1✔
407	// edge to a blinded peer.	1✔
408	hopPayloadSizeFn = edge.hopPayloadSizeFn	1✔
409	}
410
411	// Return early if no channel matches.
412	if bestPolicy == nil {	2✔
413	return nil	1✔
414	}	1✔
415
416	// We have already picked the highest fee that could be required for
417	// non-strict forwarding. To also cover the case where a lower fee
418	// channel requires a longer time lock, we modify the policy by setting
419	// the maximum encountered time lock. Note that this results in a
420	// synthetic policy that is not actually present on the routing node.
421	//
422	// The reason we do this, is that we try to maximize the chance that we
423	// get forwarded. Because we penalize pair-wise, there won't be a second
424	// chance for this node pair. But this is all only needed for nodes that
425	// have distinct policies for channels to the same peer.
426	policyCopy := *bestPolicy.policy	1✔
427	policyCopy.TimeLockDelta = maxTimelock	1✔
428	modifiedEdge := newUnifiedEdge(	1✔
429	&policyCopy, maxCapMsat.ToSatoshis(), bestPolicy.inboundFees,	1✔
430	hopPayloadSizeFn, bestPolicy.blindedPayment,	1✔
431	)	1✔
432		1✔
433	return modifiedEdge	1✔
434	}
435
436	// minAmt returns the minimum amount that can be forwarded on this connection.
UNCOV 437	func (u *edgeUnifier) minAmt() lnwire.MilliSatoshi {	×
UNCOV 438	minAmount := lnwire.MaxMilliSatoshi	×
UNCOV 439	for _, edge := range u.edges {	×
UNCOV 440	minAmount = min(minAmount, edge.policy.MinHTLC)	×
UNCOV 441	}	×
442
UNCOV 443	return minAmount	×
444	}

lightningnetwork / lnd / 15838907453

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