2539 lines
82 KiB
Go
2539 lines
82 KiB
Go
package routing
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import (
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"bytes"
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"fmt"
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"runtime"
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"sync"
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"sync/atomic"
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"time"
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"github.com/btcsuite/btcd/btcec"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil"
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"github.com/davecgh/go-spew/spew"
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"github.com/go-errors/errors"
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sphinx "github.com/lightningnetwork/lightning-onion"
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/channeldb/kvdb"
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"github.com/lightningnetwork/lnd/clock"
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"github.com/lightningnetwork/lnd/htlcswitch"
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"github.com/lightningnetwork/lnd/input"
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"github.com/lightningnetwork/lnd/lntypes"
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"github.com/lightningnetwork/lnd/lnwallet"
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"github.com/lightningnetwork/lnd/lnwallet/chanvalidate"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/multimutex"
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"github.com/lightningnetwork/lnd/record"
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"github.com/lightningnetwork/lnd/routing/chainview"
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"github.com/lightningnetwork/lnd/routing/route"
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"github.com/lightningnetwork/lnd/ticker"
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"github.com/lightningnetwork/lnd/zpay32"
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)
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const (
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// DefaultPayAttemptTimeout is the default payment attempt timeout. The
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// payment attempt timeout defines the duration after which we stop
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// trying more routes for a payment.
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DefaultPayAttemptTimeout = time.Duration(time.Second * 60)
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// DefaultChannelPruneExpiry is the default duration used to determine
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// if a channel should be pruned or not.
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DefaultChannelPruneExpiry = time.Duration(time.Hour * 24 * 14)
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// defaultStatInterval governs how often the router will log non-empty
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// stats related to processing new channels, updates, or node
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// announcements.
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defaultStatInterval = time.Minute
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)
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var (
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// ErrRouterShuttingDown is returned if the router is in the process of
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// shutting down.
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ErrRouterShuttingDown = fmt.Errorf("router shutting down")
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)
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// ChannelGraphSource represents the source of information about the topology
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// of the lightning network. It's responsible for the addition of nodes, edges,
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// applying edge updates, and returning the current block height with which the
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// topology is synchronized.
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type ChannelGraphSource interface {
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// AddNode is used to add information about a node to the router
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// database. If the node with this pubkey is not present in an existing
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// channel, it will be ignored.
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AddNode(node *channeldb.LightningNode) error
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// AddEdge is used to add edge/channel to the topology of the router,
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// after all information about channel will be gathered this
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// edge/channel might be used in construction of payment path.
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AddEdge(edge *channeldb.ChannelEdgeInfo) error
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// AddProof updates the channel edge info with proof which is needed to
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// properly announce the edge to the rest of the network.
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AddProof(chanID lnwire.ShortChannelID, proof *channeldb.ChannelAuthProof) error
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// UpdateEdge is used to update edge information, without this message
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// edge considered as not fully constructed.
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UpdateEdge(policy *channeldb.ChannelEdgePolicy) error
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// IsStaleNode returns true if the graph source has a node announcement
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// for the target node with a more recent timestamp. This method will
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// also return true if we don't have an active channel announcement for
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// the target node.
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IsStaleNode(node route.Vertex, timestamp time.Time) bool
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// IsPublicNode determines whether the given vertex is seen as a public
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// node in the graph from the graph's source node's point of view.
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IsPublicNode(node route.Vertex) (bool, error)
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// IsKnownEdge returns true if the graph source already knows of the
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// passed channel ID either as a live or zombie edge.
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IsKnownEdge(chanID lnwire.ShortChannelID) bool
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// IsStaleEdgePolicy returns true if the graph source has a channel
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// edge for the passed channel ID (and flags) that have a more recent
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// timestamp.
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IsStaleEdgePolicy(chanID lnwire.ShortChannelID, timestamp time.Time,
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flags lnwire.ChanUpdateChanFlags) bool
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// MarkEdgeLive clears an edge from our zombie index, deeming it as
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// live.
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MarkEdgeLive(chanID lnwire.ShortChannelID) error
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// ForAllOutgoingChannels is used to iterate over all channels
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// emanating from the "source" node which is the center of the
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// star-graph.
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ForAllOutgoingChannels(cb func(c *channeldb.ChannelEdgeInfo,
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e *channeldb.ChannelEdgePolicy) error) error
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// CurrentBlockHeight returns the block height from POV of the router
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// subsystem.
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CurrentBlockHeight() (uint32, error)
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// GetChannelByID return the channel by the channel id.
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GetChannelByID(chanID lnwire.ShortChannelID) (*channeldb.ChannelEdgeInfo,
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*channeldb.ChannelEdgePolicy, *channeldb.ChannelEdgePolicy, error)
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// FetchLightningNode attempts to look up a target node by its identity
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// public key. channeldb.ErrGraphNodeNotFound is returned if the node
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// doesn't exist within the graph.
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FetchLightningNode(route.Vertex) (*channeldb.LightningNode, error)
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// ForEachNode is used to iterate over every node in the known graph.
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ForEachNode(func(node *channeldb.LightningNode) error) error
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// ForEachChannel is used to iterate over every channel in the known
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// graph.
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ForEachChannel(func(chanInfo *channeldb.ChannelEdgeInfo,
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e1, e2 *channeldb.ChannelEdgePolicy) error) error
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}
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// PaymentAttemptDispatcher is used by the router to send payment attempts onto
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// the network, and receive their results.
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type PaymentAttemptDispatcher interface {
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// SendHTLC is a function that directs a link-layer switch to
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// forward a fully encoded payment to the first hop in the route
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// denoted by its public key. A non-nil error is to be returned if the
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// payment was unsuccessful.
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SendHTLC(firstHop lnwire.ShortChannelID,
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paymentID uint64,
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htlcAdd *lnwire.UpdateAddHTLC) error
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// GetPaymentResult returns the the result of the payment attempt with
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// the given paymentID. The method returns a channel where the payment
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// result will be sent when available, or an error is encountered
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// during forwarding. When a result is received on the channel, the
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// HTLC is guaranteed to no longer be in flight. The switch shutting
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// down is signaled by closing the channel. If the paymentID is
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// unknown, ErrPaymentIDNotFound will be returned.
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GetPaymentResult(paymentID uint64, paymentHash lntypes.Hash,
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deobfuscator htlcswitch.ErrorDecrypter) (
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<-chan *htlcswitch.PaymentResult, error)
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}
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// PaymentSessionSource is an interface that defines a source for the router to
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// retrive new payment sessions.
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type PaymentSessionSource interface {
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// NewPaymentSession creates a new payment session that will produce
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// routes to the given target. An optional set of routing hints can be
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// provided in order to populate additional edges to explore when
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// finding a path to the payment's destination.
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NewPaymentSession(p *LightningPayment) (PaymentSession, error)
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// NewPaymentSessionEmpty creates a new paymentSession instance that is
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// empty, and will be exhausted immediately. Used for failure reporting
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// to missioncontrol for resumed payment we don't want to make more
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// attempts for.
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NewPaymentSessionEmpty() PaymentSession
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}
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// MissionController is an interface that exposes failure reporting and
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// probability estimation.
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type MissionController interface {
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// ReportPaymentFail reports a failed payment to mission control as
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// input for future probability estimates. It returns a bool indicating
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// whether this error is a final error and no further payment attempts
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// need to be made.
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ReportPaymentFail(paymentID uint64, rt *route.Route,
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failureSourceIdx *int, failure lnwire.FailureMessage) (
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*channeldb.FailureReason, error)
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// ReportPaymentSuccess reports a successful payment to mission control as input
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// for future probability estimates.
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ReportPaymentSuccess(paymentID uint64, rt *route.Route) error
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// GetProbability is expected to return the success probability of a
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// payment from fromNode along edge.
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GetProbability(fromNode, toNode route.Vertex,
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amt lnwire.MilliSatoshi) float64
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}
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// FeeSchema is the set fee configuration for a Lightning Node on the network.
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// Using the coefficients described within the schema, the required fee to
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// forward outgoing payments can be derived.
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type FeeSchema struct {
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// BaseFee is the base amount of milli-satoshis that will be chained
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// for ANY payment forwarded.
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BaseFee lnwire.MilliSatoshi
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// FeeRate is the rate that will be charged for forwarding payments.
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// This value should be interpreted as the numerator for a fraction
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// (fixed point arithmetic) whose denominator is 1 million. As a result
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// the effective fee rate charged per mSAT will be: (amount *
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// FeeRate/1,000,000).
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FeeRate uint32
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}
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// ChannelPolicy holds the parameters that determine the policy we enforce
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// when forwarding payments on a channel. These parameters are communicated
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// to the rest of the network in ChannelUpdate messages.
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type ChannelPolicy struct {
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// FeeSchema holds the fee configuration for a channel.
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FeeSchema
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// TimeLockDelta is the required HTLC timelock delta to be used
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// when forwarding payments.
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TimeLockDelta uint32
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// MaxHTLC is the maximum HTLC size including fees we are allowed to
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// forward over this channel.
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MaxHTLC lnwire.MilliSatoshi
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// MinHTLC is the minimum HTLC size including fees we are allowed to
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// forward over this channel.
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MinHTLC *lnwire.MilliSatoshi
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}
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// Config defines the configuration for the ChannelRouter. ALL elements within
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// the configuration MUST be non-nil for the ChannelRouter to carry out its
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// duties.
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type Config struct {
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// Graph is the channel graph that the ChannelRouter will use to gather
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// metrics from and also to carry out path finding queries.
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// TODO(roasbeef): make into an interface
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Graph *channeldb.ChannelGraph
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// Chain is the router's source to the most up-to-date blockchain data.
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// All incoming advertised channels will be checked against the chain
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// to ensure that the channels advertised are still open.
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Chain lnwallet.BlockChainIO
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// ChainView is an instance of a FilteredChainView which is used to
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// watch the sub-set of the UTXO set (the set of active channels) that
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// we need in order to properly maintain the channel graph.
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ChainView chainview.FilteredChainView
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// Payer is an instance of a PaymentAttemptDispatcher and is used by
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// the router to send payment attempts onto the network, and receive
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// their results.
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Payer PaymentAttemptDispatcher
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// Control keeps track of the status of ongoing payments, ensuring we
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// can properly resume them across restarts.
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Control ControlTower
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// MissionControl is a shared memory of sorts that executions of
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// payment path finding use in order to remember which vertexes/edges
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// were pruned from prior attempts. During SendPayment execution,
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// errors sent by nodes are mapped into a vertex or edge to be pruned.
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// Each run will then take into account this set of pruned
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// vertexes/edges to reduce route failure and pass on graph information
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// gained to the next execution.
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MissionControl MissionController
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// SessionSource defines a source for the router to retrieve new payment
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// sessions.
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SessionSource PaymentSessionSource
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// ChannelPruneExpiry is the duration used to determine if a channel
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// should be pruned or not. If the delta between now and when the
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// channel was last updated is greater than ChannelPruneExpiry, then
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// the channel is marked as a zombie channel eligible for pruning.
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ChannelPruneExpiry time.Duration
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// GraphPruneInterval is used as an interval to determine how often we
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// should examine the channel graph to garbage collect zombie channels.
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GraphPruneInterval time.Duration
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// QueryBandwidth is a method that allows the router to query the lower
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// link layer to determine the up to date available bandwidth at a
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// prospective link to be traversed. If the link isn't available, then
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// a value of zero should be returned. Otherwise, the current up to
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// date knowledge of the available bandwidth of the link should be
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// returned.
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QueryBandwidth func(edge *channeldb.ChannelEdgeInfo) lnwire.MilliSatoshi
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// NextPaymentID is a method that guarantees to return a new, unique ID
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// each time it is called. This is used by the router to generate a
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// unique payment ID for each payment it attempts to send, such that
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// the switch can properly handle the HTLC.
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NextPaymentID func() (uint64, error)
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// AssumeChannelValid toggles whether or not the router will check for
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// spentness of channel outpoints. For neutrino, this saves long rescans
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// from blocking initial usage of the daemon.
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AssumeChannelValid bool
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// PathFindingConfig defines global path finding parameters.
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PathFindingConfig PathFindingConfig
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// Clock is mockable time provider.
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Clock clock.Clock
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}
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// EdgeLocator is a struct used to identify a specific edge.
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type EdgeLocator struct {
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// ChannelID is the channel of this edge.
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ChannelID uint64
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// Direction takes the value of 0 or 1 and is identical in definition to
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// the channel direction flag. A value of 0 means the direction from the
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// lower node pubkey to the higher.
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Direction uint8
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}
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// String returns a human readable version of the edgeLocator values.
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func (e *EdgeLocator) String() string {
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return fmt.Sprintf("%v:%v", e.ChannelID, e.Direction)
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}
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// ChannelRouter is the layer 3 router within the Lightning stack. Below the
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// ChannelRouter is the HtlcSwitch, and below that is the Bitcoin blockchain
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// itself. The primary role of the ChannelRouter is to respond to queries for
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// potential routes that can support a payment amount, and also general graph
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// reachability questions. The router will prune the channel graph
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// automatically as new blocks are discovered which spend certain known funding
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// outpoints, thereby closing their respective channels.
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type ChannelRouter struct {
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ntfnClientCounter uint64 // To be used atomically.
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started uint32 // To be used atomically.
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stopped uint32 // To be used atomically.
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bestHeight uint32 // To be used atomically.
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// cfg is a copy of the configuration struct that the ChannelRouter was
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// initialized with.
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cfg *Config
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// selfNode is the center of the star-graph centered around the
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// ChannelRouter. The ChannelRouter uses this node as a starting point
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// when doing any path finding.
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selfNode *channeldb.LightningNode
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// newBlocks is a channel in which new blocks connected to the end of
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// the main chain are sent over, and blocks updated after a call to
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// UpdateFilter.
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newBlocks <-chan *chainview.FilteredBlock
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// staleBlocks is a channel in which blocks disconnected fromt the end
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// of our currently known best chain are sent over.
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staleBlocks <-chan *chainview.FilteredBlock
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// networkUpdates is a channel that carries new topology updates
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// messages from outside the ChannelRouter to be processed by the
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// networkHandler.
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networkUpdates chan *routingMsg
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// topologyClients maps a client's unique notification ID to a
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// topologyClient client that contains its notification dispatch
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// channel.
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topologyClients map[uint64]*topologyClient
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// ntfnClientUpdates is a channel that's used to send new updates to
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// topology notification clients to the ChannelRouter. Updates either
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// add a new notification client, or cancel notifications for an
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// existing client.
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ntfnClientUpdates chan *topologyClientUpdate
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// channelEdgeMtx is a mutex we use to make sure we process only one
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// ChannelEdgePolicy at a time for a given channelID, to ensure
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// consistency between the various database accesses.
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channelEdgeMtx *multimutex.Mutex
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|
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// statTicker is a resumable ticker that logs the router's progress as
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// it discovers channels or receives updates.
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statTicker ticker.Ticker
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// stats tracks newly processed channels, updates, and node
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// announcements over a window of defaultStatInterval.
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stats *routerStats
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|
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sync.RWMutex
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quit chan struct{}
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wg sync.WaitGroup
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}
|
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|
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// A compile time check to ensure ChannelRouter implements the
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// ChannelGraphSource interface.
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var _ ChannelGraphSource = (*ChannelRouter)(nil)
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|
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// New creates a new instance of the ChannelRouter with the specified
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// configuration parameters. As part of initialization, if the router detects
|
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// that the channel graph isn't fully in sync with the latest UTXO (since the
|
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// channel graph is a subset of the UTXO set) set, then the router will proceed
|
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// to fully sync to the latest state of the UTXO set.
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func New(cfg Config) (*ChannelRouter, error) {
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|
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selfNode, err := cfg.Graph.SourceNode()
|
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if err != nil {
|
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return nil, err
|
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}
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|
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r := &ChannelRouter{
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cfg: &cfg,
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networkUpdates: make(chan *routingMsg),
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topologyClients: make(map[uint64]*topologyClient),
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ntfnClientUpdates: make(chan *topologyClientUpdate),
|
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channelEdgeMtx: multimutex.NewMutex(),
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selfNode: selfNode,
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statTicker: ticker.New(defaultStatInterval),
|
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stats: new(routerStats),
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quit: make(chan struct{}),
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}
|
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|
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return r, nil
|
|
}
|
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|
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// Start launches all the goroutines the ChannelRouter requires to carry out
|
|
// its duties. If the router has already been started, then this method is a
|
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// noop.
|
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func (r *ChannelRouter) Start() error {
|
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if !atomic.CompareAndSwapUint32(&r.started, 0, 1) {
|
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return nil
|
|
}
|
|
|
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log.Tracef("Channel Router starting")
|
|
|
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bestHash, bestHeight, err := r.cfg.Chain.GetBestBlock()
|
|
if err != nil {
|
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return err
|
|
}
|
|
|
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// If the graph has never been pruned, or hasn't fully been created yet,
|
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// then we don't treat this as an explicit error.
|
|
if _, _, err := r.cfg.Graph.PruneTip(); err != nil {
|
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switch {
|
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case err == channeldb.ErrGraphNeverPruned:
|
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fallthrough
|
|
case err == channeldb.ErrGraphNotFound:
|
|
// If the graph has never been pruned, then we'll set
|
|
// the prune height to the current best height of the
|
|
// chain backend.
|
|
_, err = r.cfg.Graph.PruneGraph(
|
|
nil, bestHash, uint32(bestHeight),
|
|
)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
default:
|
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return err
|
|
}
|
|
}
|
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|
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// If AssumeChannelValid is present, then we won't rely on pruning
|
|
// channels from the graph based on their spentness, but whether they
|
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// are considered zombies or not.
|
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if r.cfg.AssumeChannelValid {
|
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if err := r.pruneZombieChans(); err != nil {
|
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return err
|
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}
|
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} else {
|
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// Otherwise, we'll use our filtered chain view to prune
|
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// channels as soon as they are detected as spent on-chain.
|
|
if err := r.cfg.ChainView.Start(); err != nil {
|
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return err
|
|
}
|
|
|
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// Once the instance is active, we'll fetch the channel we'll
|
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// receive notifications over.
|
|
r.newBlocks = r.cfg.ChainView.FilteredBlocks()
|
|
r.staleBlocks = r.cfg.ChainView.DisconnectedBlocks()
|
|
|
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// Before we perform our manual block pruning, we'll construct
|
|
// and apply a fresh chain filter to the active
|
|
// FilteredChainView instance. We do this before, as otherwise
|
|
// we may miss on-chain events as the filter hasn't properly
|
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// been applied.
|
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channelView, err := r.cfg.Graph.ChannelView()
|
|
if err != nil && err != channeldb.ErrGraphNoEdgesFound {
|
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return err
|
|
}
|
|
|
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log.Infof("Filtering chain using %v channels active",
|
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len(channelView))
|
|
|
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if len(channelView) != 0 {
|
|
err = r.cfg.ChainView.UpdateFilter(
|
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channelView, uint32(bestHeight),
|
|
)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
// Before we begin normal operation of the router, we first need
|
|
// to synchronize the channel graph to the latest state of the
|
|
// UTXO set.
|
|
if err := r.syncGraphWithChain(); err != nil {
|
|
return err
|
|
}
|
|
|
|
// Finally, before we proceed, we'll prune any unconnected nodes
|
|
// from the graph in order to ensure we maintain a tight graph
|
|
// of "useful" nodes.
|
|
err = r.cfg.Graph.PruneGraphNodes()
|
|
if err != nil && err != channeldb.ErrGraphNodesNotFound {
|
|
return err
|
|
}
|
|
}
|
|
|
|
// If any payments are still in flight, we resume, to make sure their
|
|
// results are properly handled.
|
|
payments, err := r.cfg.Control.FetchInFlightPayments()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
for _, payment := range payments {
|
|
log.Infof("Resuming payment with hash %v", payment.Info.PaymentHash)
|
|
r.wg.Add(1)
|
|
go func(payment *channeldb.InFlightPayment) {
|
|
defer r.wg.Done()
|
|
|
|
// We create a dummy, empty payment session such that
|
|
// we won't make another payment attempt when the
|
|
// result for the in-flight attempt is received.
|
|
paySession := r.cfg.SessionSource.NewPaymentSessionEmpty()
|
|
|
|
// We pass in a zero timeout value, to indicate we
|
|
// don't need it to timeout. It will stop immediately
|
|
// after the existing attempt has finished anyway. We
|
|
// also set a zero fee limit, as no more routes should
|
|
// be tried.
|
|
_, _, err := r.sendPayment(
|
|
payment.Info.Value, 0,
|
|
payment.Info.PaymentHash, 0, paySession,
|
|
)
|
|
if err != nil {
|
|
log.Errorf("Resuming payment with hash %v "+
|
|
"failed: %v.", payment.Info.PaymentHash, err)
|
|
return
|
|
}
|
|
|
|
log.Infof("Resumed payment with hash %v completed.",
|
|
payment.Info.PaymentHash)
|
|
}(payment)
|
|
}
|
|
|
|
r.wg.Add(1)
|
|
go r.networkHandler()
|
|
|
|
return nil
|
|
}
|
|
|
|
// Stop signals the ChannelRouter to gracefully halt all routines. This method
|
|
// will *block* until all goroutines have excited. If the channel router has
|
|
// already stopped then this method will return immediately.
|
|
func (r *ChannelRouter) Stop() error {
|
|
if !atomic.CompareAndSwapUint32(&r.stopped, 0, 1) {
|
|
return nil
|
|
}
|
|
|
|
log.Tracef("Channel Router shutting down")
|
|
|
|
// Our filtered chain view could've only been started if
|
|
// AssumeChannelValid isn't present.
|
|
if !r.cfg.AssumeChannelValid {
|
|
if err := r.cfg.ChainView.Stop(); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
close(r.quit)
|
|
r.wg.Wait()
|
|
|
|
return nil
|
|
}
|
|
|
|
// syncGraphWithChain attempts to synchronize the current channel graph with
|
|
// the latest UTXO set state. This process involves pruning from the channel
|
|
// graph any channels which have been closed by spending their funding output
|
|
// since we've been down.
|
|
func (r *ChannelRouter) syncGraphWithChain() error {
|
|
// First, we'll need to check to see if we're already in sync with the
|
|
// latest state of the UTXO set.
|
|
bestHash, bestHeight, err := r.cfg.Chain.GetBestBlock()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
r.bestHeight = uint32(bestHeight)
|
|
|
|
pruneHash, pruneHeight, err := r.cfg.Graph.PruneTip()
|
|
if err != nil {
|
|
switch {
|
|
// If the graph has never been pruned, or hasn't fully been
|
|
// created yet, then we don't treat this as an explicit error.
|
|
case err == channeldb.ErrGraphNeverPruned:
|
|
case err == channeldb.ErrGraphNotFound:
|
|
default:
|
|
return err
|
|
}
|
|
}
|
|
|
|
log.Infof("Prune tip for Channel Graph: height=%v, hash=%v", pruneHeight,
|
|
pruneHash)
|
|
|
|
switch {
|
|
|
|
// If the graph has never been pruned, then we can exit early as this
|
|
// entails it's being created for the first time and hasn't seen any
|
|
// block or created channels.
|
|
case pruneHeight == 0 || pruneHash == nil:
|
|
return nil
|
|
|
|
// If the block hashes and heights match exactly, then we don't need to
|
|
// prune the channel graph as we're already fully in sync.
|
|
case bestHash.IsEqual(pruneHash) && uint32(bestHeight) == pruneHeight:
|
|
return nil
|
|
}
|
|
|
|
// If the main chain blockhash at prune height is different from the
|
|
// prune hash, this might indicate the database is on a stale branch.
|
|
mainBlockHash, err := r.cfg.Chain.GetBlockHash(int64(pruneHeight))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// While we are on a stale branch of the chain, walk backwards to find
|
|
// first common block.
|
|
for !pruneHash.IsEqual(mainBlockHash) {
|
|
log.Infof("channel graph is stale. Disconnecting block %v "+
|
|
"(hash=%v)", pruneHeight, pruneHash)
|
|
// Prune the graph for every channel that was opened at height
|
|
// >= pruneHeight.
|
|
_, err := r.cfg.Graph.DisconnectBlockAtHeight(pruneHeight)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
pruneHash, pruneHeight, err = r.cfg.Graph.PruneTip()
|
|
if err != nil {
|
|
switch {
|
|
// If at this point the graph has never been pruned, we
|
|
// can exit as this entails we are back to the point
|
|
// where it hasn't seen any block or created channels,
|
|
// alas there's nothing left to prune.
|
|
case err == channeldb.ErrGraphNeverPruned:
|
|
return nil
|
|
case err == channeldb.ErrGraphNotFound:
|
|
return nil
|
|
default:
|
|
return err
|
|
}
|
|
}
|
|
mainBlockHash, err = r.cfg.Chain.GetBlockHash(int64(pruneHeight))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
log.Infof("Syncing channel graph from height=%v (hash=%v) to height=%v "+
|
|
"(hash=%v)", pruneHeight, pruneHash, bestHeight, bestHash)
|
|
|
|
// If we're not yet caught up, then we'll walk forward in the chain
|
|
// pruning the channel graph with each new block that hasn't yet been
|
|
// consumed by the channel graph.
|
|
var spentOutputs []*wire.OutPoint
|
|
for nextHeight := pruneHeight + 1; nextHeight <= uint32(bestHeight); nextHeight++ {
|
|
// Break out of the rescan early if a shutdown has been
|
|
// requested, otherwise long rescans will block the daemon from
|
|
// shutting down promptly.
|
|
select {
|
|
case <-r.quit:
|
|
return ErrRouterShuttingDown
|
|
default:
|
|
}
|
|
|
|
// Using the next height, request a manual block pruning from
|
|
// the chainview for the particular block hash.
|
|
nextHash, err := r.cfg.Chain.GetBlockHash(int64(nextHeight))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
filterBlock, err := r.cfg.ChainView.FilterBlock(nextHash)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// We're only interested in all prior outputs that have been
|
|
// spent in the block, so collate all the referenced previous
|
|
// outpoints within each tx and input.
|
|
for _, tx := range filterBlock.Transactions {
|
|
for _, txIn := range tx.TxIn {
|
|
spentOutputs = append(spentOutputs,
|
|
&txIn.PreviousOutPoint)
|
|
}
|
|
}
|
|
}
|
|
|
|
// With the spent outputs gathered, attempt to prune the channel graph,
|
|
// also passing in the best hash+height so the prune tip can be updated.
|
|
closedChans, err := r.cfg.Graph.PruneGraph(
|
|
spentOutputs, bestHash, uint32(bestHeight),
|
|
)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
log.Infof("Graph pruning complete: %v channels were closed since "+
|
|
"height %v", len(closedChans), pruneHeight)
|
|
return nil
|
|
}
|
|
|
|
// pruneZombieChans is a method that will be called periodically to prune out
|
|
// any "zombie" channels. We consider channels zombies if *both* edges haven't
|
|
// been updated since our zombie horizon. If AssumeChannelValid is present,
|
|
// we'll also consider channels zombies if *both* edges are disabled. This
|
|
// usually signals that a channel has been closed on-chain. We do this
|
|
// periodically to keep a healthy, lively routing table.
|
|
func (r *ChannelRouter) pruneZombieChans() error {
|
|
chansToPrune := make(map[uint64]struct{})
|
|
chanExpiry := r.cfg.ChannelPruneExpiry
|
|
|
|
log.Infof("Examining channel graph for zombie channels")
|
|
|
|
// A helper method to detect if the channel belongs to this node
|
|
isSelfChannelEdge := func(info *channeldb.ChannelEdgeInfo) bool {
|
|
return info.NodeKey1Bytes == r.selfNode.PubKeyBytes ||
|
|
info.NodeKey2Bytes == r.selfNode.PubKeyBytes
|
|
}
|
|
|
|
// First, we'll collect all the channels which are eligible for garbage
|
|
// collection due to being zombies.
|
|
filterPruneChans := func(info *channeldb.ChannelEdgeInfo,
|
|
e1, e2 *channeldb.ChannelEdgePolicy) error {
|
|
|
|
// Exit early in case this channel is already marked to be pruned
|
|
if _, markedToPrune := chansToPrune[info.ChannelID]; markedToPrune {
|
|
return nil
|
|
}
|
|
|
|
// We'll ensure that we don't attempt to prune our *own*
|
|
// channels from the graph, as in any case this should be
|
|
// re-advertised by the sub-system above us.
|
|
if isSelfChannelEdge(info) {
|
|
return nil
|
|
}
|
|
|
|
// If *both* edges haven't been updated for a period of
|
|
// chanExpiry, then we'll mark the channel itself as eligible
|
|
// for graph pruning.
|
|
var e1Zombie, e2Zombie bool
|
|
if e1 != nil {
|
|
e1Zombie = time.Since(e1.LastUpdate) >= chanExpiry
|
|
if e1Zombie {
|
|
log.Tracef("Edge #1 of ChannelID(%v) last "+
|
|
"update: %v", info.ChannelID,
|
|
e1.LastUpdate)
|
|
}
|
|
}
|
|
if e2 != nil {
|
|
e2Zombie = time.Since(e2.LastUpdate) >= chanExpiry
|
|
if e2Zombie {
|
|
log.Tracef("Edge #2 of ChannelID(%v) last "+
|
|
"update: %v", info.ChannelID,
|
|
e2.LastUpdate)
|
|
}
|
|
}
|
|
|
|
// If the channel is not considered zombie, we can move on to
|
|
// the next.
|
|
if !e1Zombie || !e2Zombie {
|
|
return nil
|
|
}
|
|
|
|
log.Debugf("ChannelID(%v) is a zombie, collecting to prune",
|
|
info.ChannelID)
|
|
|
|
// TODO(roasbeef): add ability to delete single directional edge
|
|
chansToPrune[info.ChannelID] = struct{}{}
|
|
|
|
return nil
|
|
}
|
|
|
|
// If AssumeChannelValid is present we'll look at the disabled bit for both
|
|
// edges. If they're both disabled, then we can interpret this as the
|
|
// channel being closed and can prune it from our graph.
|
|
if r.cfg.AssumeChannelValid {
|
|
disabledChanIDs, err := r.cfg.Graph.DisabledChannelIDs()
|
|
if err != nil {
|
|
return fmt.Errorf("unable to get disabled channels ids "+
|
|
"chans: %v", err)
|
|
}
|
|
|
|
disabledEdges, err := r.cfg.Graph.FetchChanInfos(disabledChanIDs)
|
|
if err != nil {
|
|
return fmt.Errorf("unable to fetch disabled channels edges "+
|
|
"chans: %v", err)
|
|
}
|
|
|
|
// Ensuring we won't prune our own channel from the graph.
|
|
for _, disabledEdge := range disabledEdges {
|
|
if !isSelfChannelEdge(disabledEdge.Info) {
|
|
chansToPrune[disabledEdge.Info.ChannelID] = struct{}{}
|
|
}
|
|
}
|
|
}
|
|
|
|
startTime := time.Unix(0, 0)
|
|
endTime := time.Now().Add(-1 * chanExpiry)
|
|
oldEdges, err := r.cfg.Graph.ChanUpdatesInHorizon(startTime, endTime)
|
|
if err != nil {
|
|
return fmt.Errorf("unable to fetch expired channel updates "+
|
|
"chans: %v", err)
|
|
}
|
|
|
|
for _, u := range oldEdges {
|
|
filterPruneChans(u.Info, u.Policy1, u.Policy2)
|
|
}
|
|
|
|
log.Infof("Pruning %v zombie channels", len(chansToPrune))
|
|
|
|
// With the set of zombie-like channels obtained, we'll do another pass
|
|
// to delete them from the channel graph.
|
|
toPrune := make([]uint64, 0, len(chansToPrune))
|
|
for chanID := range chansToPrune {
|
|
toPrune = append(toPrune, chanID)
|
|
log.Tracef("Pruning zombie channel with ChannelID(%v)", chanID)
|
|
}
|
|
if err := r.cfg.Graph.DeleteChannelEdges(toPrune...); err != nil {
|
|
return fmt.Errorf("unable to delete zombie channels: %v", err)
|
|
}
|
|
|
|
// With the channels pruned, we'll also attempt to prune any nodes that
|
|
// were a part of them.
|
|
err = r.cfg.Graph.PruneGraphNodes()
|
|
if err != nil && err != channeldb.ErrGraphNodesNotFound {
|
|
return fmt.Errorf("unable to prune graph nodes: %v", err)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// networkHandler is the primary goroutine for the ChannelRouter. The roles of
|
|
// this goroutine include answering queries related to the state of the
|
|
// network, pruning the graph on new block notification, applying network
|
|
// updates, and registering new topology clients.
|
|
//
|
|
// NOTE: This MUST be run as a goroutine.
|
|
func (r *ChannelRouter) networkHandler() {
|
|
defer r.wg.Done()
|
|
|
|
graphPruneTicker := time.NewTicker(r.cfg.GraphPruneInterval)
|
|
defer graphPruneTicker.Stop()
|
|
|
|
defer r.statTicker.Stop()
|
|
|
|
r.stats.Reset()
|
|
|
|
// We'll use this validation barrier to ensure that we process all jobs
|
|
// in the proper order during parallel validation.
|
|
validationBarrier := NewValidationBarrier(runtime.NumCPU()*4, r.quit)
|
|
|
|
for {
|
|
|
|
// If there are stats, resume the statTicker.
|
|
if !r.stats.Empty() {
|
|
r.statTicker.Resume()
|
|
}
|
|
|
|
select {
|
|
// A new fully validated network update has just arrived. As a
|
|
// result we'll modify the channel graph accordingly depending
|
|
// on the exact type of the message.
|
|
case update := <-r.networkUpdates:
|
|
// We'll set up any dependants, and wait until a free
|
|
// slot for this job opens up, this allow us to not
|
|
// have thousands of goroutines active.
|
|
validationBarrier.InitJobDependencies(update.msg)
|
|
|
|
r.wg.Add(1)
|
|
go func() {
|
|
defer r.wg.Done()
|
|
defer validationBarrier.CompleteJob()
|
|
|
|
// If this message has an existing dependency,
|
|
// then we'll wait until that has been fully
|
|
// validated before we proceed.
|
|
err := validationBarrier.WaitForDependants(
|
|
update.msg,
|
|
)
|
|
if err != nil {
|
|
if err != ErrVBarrierShuttingDown {
|
|
log.Warnf("unexpected error "+
|
|
"during validation "+
|
|
"barrier shutdown: %v",
|
|
err)
|
|
}
|
|
return
|
|
}
|
|
|
|
// Process the routing update to determine if
|
|
// this is either a new update from our PoV or
|
|
// an update to a prior vertex/edge we
|
|
// previously accepted.
|
|
err = r.processUpdate(update.msg)
|
|
update.err <- err
|
|
|
|
// If this message had any dependencies, then
|
|
// we can now signal them to continue.
|
|
validationBarrier.SignalDependants(update.msg)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
// Send off a new notification for the newly
|
|
// accepted update.
|
|
topChange := &TopologyChange{}
|
|
err = addToTopologyChange(
|
|
r.cfg.Graph, topChange, update.msg,
|
|
)
|
|
if err != nil {
|
|
log.Errorf("unable to update topology "+
|
|
"change notification: %v", err)
|
|
return
|
|
}
|
|
|
|
if !topChange.isEmpty() {
|
|
r.notifyTopologyChange(topChange)
|
|
}
|
|
}()
|
|
|
|
// TODO(roasbeef): remove all unconnected vertexes
|
|
// after N blocks pass with no corresponding
|
|
// announcements.
|
|
|
|
case chainUpdate, ok := <-r.staleBlocks:
|
|
// If the channel has been closed, then this indicates
|
|
// the daemon is shutting down, so we exit ourselves.
|
|
if !ok {
|
|
return
|
|
}
|
|
|
|
// Since this block is stale, we update our best height
|
|
// to the previous block.
|
|
blockHeight := uint32(chainUpdate.Height)
|
|
atomic.StoreUint32(&r.bestHeight, blockHeight-1)
|
|
|
|
// Update the channel graph to reflect that this block
|
|
// was disconnected.
|
|
_, err := r.cfg.Graph.DisconnectBlockAtHeight(blockHeight)
|
|
if err != nil {
|
|
log.Errorf("unable to prune graph with stale "+
|
|
"block: %v", err)
|
|
continue
|
|
}
|
|
|
|
// TODO(halseth): notify client about the reorg?
|
|
|
|
// A new block has arrived, so we can prune the channel graph
|
|
// of any channels which were closed in the block.
|
|
case chainUpdate, ok := <-r.newBlocks:
|
|
// If the channel has been closed, then this indicates
|
|
// the daemon is shutting down, so we exit ourselves.
|
|
if !ok {
|
|
return
|
|
}
|
|
|
|
// We'll ensure that any new blocks received attach
|
|
// directly to the end of our main chain. If not, then
|
|
// we've somehow missed some blocks. We don't process
|
|
// this block as otherwise, we may miss on-chain
|
|
// events.
|
|
currentHeight := atomic.LoadUint32(&r.bestHeight)
|
|
if chainUpdate.Height != currentHeight+1 {
|
|
log.Errorf("out of order block: expecting "+
|
|
"height=%v, got height=%v", currentHeight+1,
|
|
chainUpdate.Height)
|
|
continue
|
|
}
|
|
|
|
// Once a new block arrives, we update our running
|
|
// track of the height of the chain tip.
|
|
blockHeight := uint32(chainUpdate.Height)
|
|
atomic.StoreUint32(&r.bestHeight, blockHeight)
|
|
log.Infof("Pruning channel graph using block %v (height=%v)",
|
|
chainUpdate.Hash, blockHeight)
|
|
|
|
// We're only interested in all prior outputs that have
|
|
// been spent in the block, so collate all the
|
|
// referenced previous outpoints within each tx and
|
|
// input.
|
|
var spentOutputs []*wire.OutPoint
|
|
for _, tx := range chainUpdate.Transactions {
|
|
for _, txIn := range tx.TxIn {
|
|
spentOutputs = append(spentOutputs,
|
|
&txIn.PreviousOutPoint)
|
|
}
|
|
}
|
|
|
|
// With the spent outputs gathered, attempt to prune
|
|
// the channel graph, also passing in the hash+height
|
|
// of the block being pruned so the prune tip can be
|
|
// updated.
|
|
chansClosed, err := r.cfg.Graph.PruneGraph(spentOutputs,
|
|
&chainUpdate.Hash, chainUpdate.Height)
|
|
if err != nil {
|
|
log.Errorf("unable to prune routing table: %v", err)
|
|
continue
|
|
}
|
|
|
|
log.Infof("Block %v (height=%v) closed %v channels",
|
|
chainUpdate.Hash, blockHeight, len(chansClosed))
|
|
|
|
if len(chansClosed) == 0 {
|
|
continue
|
|
}
|
|
|
|
// Notify all currently registered clients of the newly
|
|
// closed channels.
|
|
closeSummaries := createCloseSummaries(blockHeight, chansClosed...)
|
|
r.notifyTopologyChange(&TopologyChange{
|
|
ClosedChannels: closeSummaries,
|
|
})
|
|
|
|
// A new notification client update has arrived. We're either
|
|
// gaining a new client, or cancelling notifications for an
|
|
// existing client.
|
|
case ntfnUpdate := <-r.ntfnClientUpdates:
|
|
clientID := ntfnUpdate.clientID
|
|
|
|
if ntfnUpdate.cancel {
|
|
r.RLock()
|
|
client, ok := r.topologyClients[ntfnUpdate.clientID]
|
|
r.RUnlock()
|
|
if ok {
|
|
r.Lock()
|
|
delete(r.topologyClients, clientID)
|
|
r.Unlock()
|
|
|
|
close(client.exit)
|
|
client.wg.Wait()
|
|
|
|
close(client.ntfnChan)
|
|
}
|
|
|
|
continue
|
|
}
|
|
|
|
r.Lock()
|
|
r.topologyClients[ntfnUpdate.clientID] = &topologyClient{
|
|
ntfnChan: ntfnUpdate.ntfnChan,
|
|
exit: make(chan struct{}),
|
|
}
|
|
r.Unlock()
|
|
|
|
// The graph prune ticker has ticked, so we'll examine the
|
|
// state of the known graph to filter out any zombie channels
|
|
// for pruning.
|
|
case <-graphPruneTicker.C:
|
|
if err := r.pruneZombieChans(); err != nil {
|
|
log.Errorf("Unable to prune zombies: %v", err)
|
|
}
|
|
|
|
// Log any stats if we've processed a non-empty number of
|
|
// channels, updates, or nodes. We'll only pause the ticker if
|
|
// the last window contained no updates to avoid resuming and
|
|
// pausing while consecutive windows contain new info.
|
|
case <-r.statTicker.Ticks():
|
|
if !r.stats.Empty() {
|
|
log.Infof(r.stats.String())
|
|
} else {
|
|
r.statTicker.Pause()
|
|
}
|
|
r.stats.Reset()
|
|
|
|
// The router has been signalled to exit, to we exit our main
|
|
// loop so the wait group can be decremented.
|
|
case <-r.quit:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// assertNodeAnnFreshness returns a non-nil error if we have an announcement in
|
|
// the database for the passed node with a timestamp newer than the passed
|
|
// timestamp. ErrIgnored will be returned if we already have the node, and
|
|
// ErrOutdated will be returned if we have a timestamp that's after the new
|
|
// timestamp.
|
|
func (r *ChannelRouter) assertNodeAnnFreshness(node route.Vertex,
|
|
msgTimestamp time.Time) error {
|
|
|
|
// If we are not already aware of this node, it means that we don't
|
|
// know about any channel using this node. To avoid a DoS attack by
|
|
// node announcements, we will ignore such nodes. If we do know about
|
|
// this node, check that this update brings info newer than what we
|
|
// already have.
|
|
lastUpdate, exists, err := r.cfg.Graph.HasLightningNode(node)
|
|
if err != nil {
|
|
return errors.Errorf("unable to query for the "+
|
|
"existence of node: %v", err)
|
|
}
|
|
if !exists {
|
|
return newErrf(ErrIgnored, "Ignoring node announcement"+
|
|
" for node not found in channel graph (%x)",
|
|
node[:])
|
|
}
|
|
|
|
// If we've reached this point then we're aware of the vertex being
|
|
// advertised. So we now check if the new message has a new time stamp,
|
|
// if not then we won't accept the new data as it would override newer
|
|
// data.
|
|
if !lastUpdate.Before(msgTimestamp) {
|
|
return newErrf(ErrOutdated, "Ignoring outdated "+
|
|
"announcement for %x", node[:])
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// processUpdate processes a new relate authenticated channel/edge, node or
|
|
// channel/edge update network update. If the update didn't affect the internal
|
|
// state of the draft due to either being out of date, invalid, or redundant,
|
|
// then error is returned.
|
|
func (r *ChannelRouter) processUpdate(msg interface{}) error {
|
|
switch msg := msg.(type) {
|
|
case *channeldb.LightningNode:
|
|
// Before we add the node to the database, we'll check to see
|
|
// if the announcement is "fresh" or not. If it isn't, then
|
|
// we'll return an error.
|
|
err := r.assertNodeAnnFreshness(msg.PubKeyBytes, msg.LastUpdate)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := r.cfg.Graph.AddLightningNode(msg); err != nil {
|
|
return errors.Errorf("unable to add node %v to the "+
|
|
"graph: %v", msg.PubKeyBytes, err)
|
|
}
|
|
|
|
log.Tracef("Updated vertex data for node=%x", msg.PubKeyBytes)
|
|
r.stats.incNumNodeUpdates()
|
|
|
|
case *channeldb.ChannelEdgeInfo:
|
|
// Prior to processing the announcement we first check if we
|
|
// already know of this channel, if so, then we can exit early.
|
|
_, _, exists, isZombie, err := r.cfg.Graph.HasChannelEdge(
|
|
msg.ChannelID,
|
|
)
|
|
if err != nil && err != channeldb.ErrGraphNoEdgesFound {
|
|
return errors.Errorf("unable to check for edge "+
|
|
"existence: %v", err)
|
|
}
|
|
if isZombie {
|
|
return newErrf(ErrIgnored, "ignoring msg for zombie "+
|
|
"chan_id=%v", msg.ChannelID)
|
|
}
|
|
if exists {
|
|
return newErrf(ErrIgnored, "ignoring msg for known "+
|
|
"chan_id=%v", msg.ChannelID)
|
|
}
|
|
|
|
// If AssumeChannelValid is present, then we are unable to
|
|
// perform any of the expensive checks below, so we'll
|
|
// short-circuit our path straight to adding the edge to our
|
|
// graph.
|
|
if r.cfg.AssumeChannelValid {
|
|
if err := r.cfg.Graph.AddChannelEdge(msg); err != nil {
|
|
return fmt.Errorf("unable to add edge: %v", err)
|
|
}
|
|
log.Tracef("New channel discovered! Link "+
|
|
"connects %x and %x with ChannelID(%v)",
|
|
msg.NodeKey1Bytes, msg.NodeKey2Bytes,
|
|
msg.ChannelID)
|
|
r.stats.incNumEdgesDiscovered()
|
|
|
|
break
|
|
}
|
|
|
|
// Before we can add the channel to the channel graph, we need
|
|
// to obtain the full funding outpoint that's encoded within
|
|
// the channel ID.
|
|
channelID := lnwire.NewShortChanIDFromInt(msg.ChannelID)
|
|
fundingTx, err := r.fetchFundingTx(&channelID)
|
|
if err != nil {
|
|
return errors.Errorf("unable to fetch funding tx for "+
|
|
"chan_id=%v: %v", msg.ChannelID, err)
|
|
}
|
|
|
|
// Recreate witness output to be sure that declared in channel
|
|
// edge bitcoin keys and channel value corresponds to the
|
|
// reality.
|
|
witnessScript, err := input.GenMultiSigScript(
|
|
msg.BitcoinKey1Bytes[:], msg.BitcoinKey2Bytes[:],
|
|
)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
pkScript, err := input.WitnessScriptHash(witnessScript)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Next we'll validate that this channel is actually well
|
|
// formed. If this check fails, then this channel either
|
|
// doesn't exist, or isn't the one that was meant to be created
|
|
// according to the passed channel proofs.
|
|
fundingPoint, err := chanvalidate.Validate(&chanvalidate.Context{
|
|
Locator: &chanvalidate.ShortChanIDChanLocator{
|
|
ID: channelID,
|
|
},
|
|
MultiSigPkScript: pkScript,
|
|
FundingTx: fundingTx,
|
|
})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Now that we have the funding outpoint of the channel, ensure
|
|
// that it hasn't yet been spent. If so, then this channel has
|
|
// been closed so we'll ignore it.
|
|
fundingPkScript, err := input.WitnessScriptHash(witnessScript)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
chanUtxo, err := r.cfg.Chain.GetUtxo(
|
|
fundingPoint, fundingPkScript, channelID.BlockHeight,
|
|
r.quit,
|
|
)
|
|
if err != nil {
|
|
return fmt.Errorf("unable to fetch utxo "+
|
|
"for chan_id=%v, chan_point=%v: %v",
|
|
msg.ChannelID, fundingPoint, err)
|
|
}
|
|
|
|
// TODO(roasbeef): this is a hack, needs to be removed
|
|
// after commitment fees are dynamic.
|
|
msg.Capacity = btcutil.Amount(chanUtxo.Value)
|
|
msg.ChannelPoint = *fundingPoint
|
|
if err := r.cfg.Graph.AddChannelEdge(msg); err != nil {
|
|
return errors.Errorf("unable to add edge: %v", err)
|
|
}
|
|
|
|
log.Tracef("New channel discovered! Link "+
|
|
"connects %x and %x with ChannelPoint(%v): "+
|
|
"chan_id=%v, capacity=%v",
|
|
msg.NodeKey1Bytes, msg.NodeKey2Bytes,
|
|
fundingPoint, msg.ChannelID, msg.Capacity)
|
|
r.stats.incNumEdgesDiscovered()
|
|
|
|
// As a new edge has been added to the channel graph, we'll
|
|
// update the current UTXO filter within our active
|
|
// FilteredChainView so we are notified if/when this channel is
|
|
// closed.
|
|
filterUpdate := []channeldb.EdgePoint{
|
|
{
|
|
FundingPkScript: fundingPkScript,
|
|
OutPoint: *fundingPoint,
|
|
},
|
|
}
|
|
err = r.cfg.ChainView.UpdateFilter(
|
|
filterUpdate, atomic.LoadUint32(&r.bestHeight),
|
|
)
|
|
if err != nil {
|
|
return errors.Errorf("unable to update chain "+
|
|
"view: %v", err)
|
|
}
|
|
|
|
case *channeldb.ChannelEdgePolicy:
|
|
// We make sure to hold the mutex for this channel ID,
|
|
// such that no other goroutine is concurrently doing
|
|
// database accesses for the same channel ID.
|
|
r.channelEdgeMtx.Lock(msg.ChannelID)
|
|
defer r.channelEdgeMtx.Unlock(msg.ChannelID)
|
|
|
|
edge1Timestamp, edge2Timestamp, exists, isZombie, err :=
|
|
r.cfg.Graph.HasChannelEdge(msg.ChannelID)
|
|
if err != nil && err != channeldb.ErrGraphNoEdgesFound {
|
|
return errors.Errorf("unable to check for edge "+
|
|
"existence: %v", err)
|
|
|
|
}
|
|
|
|
// If the channel is marked as a zombie in our database, and
|
|
// we consider this a stale update, then we should not apply the
|
|
// policy.
|
|
isStaleUpdate := time.Since(msg.LastUpdate) > r.cfg.ChannelPruneExpiry
|
|
if isZombie && isStaleUpdate {
|
|
return newErrf(ErrIgnored, "ignoring stale update "+
|
|
"(flags=%v|%v) for zombie chan_id=%v",
|
|
msg.MessageFlags, msg.ChannelFlags,
|
|
msg.ChannelID)
|
|
}
|
|
|
|
// If the channel doesn't exist in our database, we cannot
|
|
// apply the updated policy.
|
|
if !exists {
|
|
return newErrf(ErrIgnored, "ignoring update "+
|
|
"(flags=%v|%v) for unknown chan_id=%v",
|
|
msg.MessageFlags, msg.ChannelFlags,
|
|
msg.ChannelID)
|
|
}
|
|
|
|
// As edges are directional edge node has a unique policy for
|
|
// the direction of the edge they control. Therefore we first
|
|
// check if we already have the most up to date information for
|
|
// that edge. If this message has a timestamp not strictly
|
|
// newer than what we already know of we can exit early.
|
|
switch {
|
|
|
|
// A flag set of 0 indicates this is an announcement for the
|
|
// "first" node in the channel.
|
|
case msg.ChannelFlags&lnwire.ChanUpdateDirection == 0:
|
|
|
|
// Ignore outdated message.
|
|
if !edge1Timestamp.Before(msg.LastUpdate) {
|
|
return newErrf(ErrOutdated, "Ignoring "+
|
|
"outdated update (flags=%v|%v) for "+
|
|
"known chan_id=%v", msg.MessageFlags,
|
|
msg.ChannelFlags, msg.ChannelID)
|
|
}
|
|
|
|
// Similarly, a flag set of 1 indicates this is an announcement
|
|
// for the "second" node in the channel.
|
|
case msg.ChannelFlags&lnwire.ChanUpdateDirection == 1:
|
|
|
|
// Ignore outdated message.
|
|
if !edge2Timestamp.Before(msg.LastUpdate) {
|
|
return newErrf(ErrOutdated, "Ignoring "+
|
|
"outdated update (flags=%v|%v) for "+
|
|
"known chan_id=%v", msg.MessageFlags,
|
|
msg.ChannelFlags, msg.ChannelID)
|
|
}
|
|
}
|
|
|
|
// Now that we know this isn't a stale update, we'll apply the
|
|
// new edge policy to the proper directional edge within the
|
|
// channel graph.
|
|
if err = r.cfg.Graph.UpdateEdgePolicy(msg); err != nil {
|
|
err := errors.Errorf("unable to add channel: %v", err)
|
|
log.Error(err)
|
|
return err
|
|
}
|
|
|
|
log.Tracef("New channel update applied: %v",
|
|
newLogClosure(func() string { return spew.Sdump(msg) }))
|
|
r.stats.incNumChannelUpdates()
|
|
|
|
default:
|
|
return errors.Errorf("wrong routing update message type")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// fetchFundingTx returns the funding transaction identified by the passed
|
|
// short channel ID.
|
|
//
|
|
// TODO(roasbeef): replace with call to GetBlockTransaction? (would allow to
|
|
// later use getblocktxn)
|
|
func (r *ChannelRouter) fetchFundingTx(
|
|
chanID *lnwire.ShortChannelID) (*wire.MsgTx, error) {
|
|
|
|
// First fetch the block hash by the block number encoded, then use
|
|
// that hash to fetch the block itself.
|
|
blockNum := int64(chanID.BlockHeight)
|
|
blockHash, err := r.cfg.Chain.GetBlockHash(blockNum)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
fundingBlock, err := r.cfg.Chain.GetBlock(blockHash)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// As a sanity check, ensure that the advertised transaction index is
|
|
// within the bounds of the total number of transactions within a
|
|
// block.
|
|
numTxns := uint32(len(fundingBlock.Transactions))
|
|
if chanID.TxIndex > numTxns-1 {
|
|
return nil, fmt.Errorf("tx_index=#%v is out of range "+
|
|
"(max_index=%v), network_chan_id=%v", chanID.TxIndex,
|
|
numTxns-1, chanID)
|
|
}
|
|
|
|
return fundingBlock.Transactions[chanID.TxIndex], nil
|
|
}
|
|
|
|
// routingMsg couples a routing related routing topology update to the
|
|
// error channel.
|
|
type routingMsg struct {
|
|
msg interface{}
|
|
err chan error
|
|
}
|
|
|
|
// FindRoute attempts to query the ChannelRouter for the optimum path to a
|
|
// particular target destination to which it is able to send `amt` after
|
|
// factoring in channel capacities and cumulative fees along the route.
|
|
func (r *ChannelRouter) FindRoute(source, target route.Vertex,
|
|
amt lnwire.MilliSatoshi, restrictions *RestrictParams,
|
|
destCustomRecords record.CustomSet,
|
|
routeHints map[route.Vertex][]*channeldb.ChannelEdgePolicy,
|
|
finalExpiry uint16) (*route.Route, error) {
|
|
|
|
log.Debugf("Searching for path to %v, sending %v", target, amt)
|
|
|
|
// We'll attempt to obtain a set of bandwidth hints that can help us
|
|
// eliminate certain routes early on in the path finding process.
|
|
bandwidthHints, err := generateBandwidthHints(
|
|
r.selfNode, r.cfg.QueryBandwidth,
|
|
)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// We'll fetch the current block height so we can properly calculate the
|
|
// required HTLC time locks within the route.
|
|
_, currentHeight, err := r.cfg.Chain.GetBestBlock()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Now that we know the destination is reachable within the graph, we'll
|
|
// execute our path finding algorithm.
|
|
finalHtlcExpiry := currentHeight + int32(finalExpiry)
|
|
|
|
routingTx, err := newDbRoutingTx(r.cfg.Graph)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer func() {
|
|
err := routingTx.close()
|
|
if err != nil {
|
|
log.Errorf("Error closing db tx: %v", err)
|
|
}
|
|
}()
|
|
|
|
path, err := findPath(
|
|
&graphParams{
|
|
additionalEdges: routeHints,
|
|
bandwidthHints: bandwidthHints,
|
|
graph: routingTx,
|
|
},
|
|
restrictions,
|
|
&r.cfg.PathFindingConfig,
|
|
source, target, amt, finalHtlcExpiry,
|
|
)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Create the route with absolute time lock values.
|
|
route, err := newRoute(
|
|
source, path, uint32(currentHeight),
|
|
finalHopParams{
|
|
amt: amt,
|
|
totalAmt: amt,
|
|
cltvDelta: finalExpiry,
|
|
records: destCustomRecords,
|
|
},
|
|
)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
go log.Tracef("Obtained path to send %v to %x: %v",
|
|
amt, target, newLogClosure(func() string {
|
|
return spew.Sdump(route)
|
|
}),
|
|
)
|
|
|
|
return route, nil
|
|
}
|
|
|
|
// generateNewSessionKey generates a new ephemeral private key to be used for a
|
|
// payment attempt.
|
|
func generateNewSessionKey() (*btcec.PrivateKey, error) {
|
|
// Generate a new random session key to ensure that we don't trigger
|
|
// any replay.
|
|
//
|
|
// TODO(roasbeef): add more sources of randomness?
|
|
return btcec.NewPrivateKey(btcec.S256())
|
|
}
|
|
|
|
// generateSphinxPacket generates then encodes a sphinx packet which encodes
|
|
// the onion route specified by the passed layer 3 route. The blob returned
|
|
// from this function can immediately be included within an HTLC add packet to
|
|
// be sent to the first hop within the route.
|
|
func generateSphinxPacket(rt *route.Route, paymentHash []byte,
|
|
sessionKey *btcec.PrivateKey) ([]byte, *sphinx.Circuit, error) {
|
|
|
|
// Now that we know we have an actual route, we'll map the route into a
|
|
// sphinx payument path which includes per-hop paylods for each hop
|
|
// that give each node within the route the necessary information
|
|
// (fees, CLTV value, etc) to properly forward the payment.
|
|
sphinxPath, err := rt.ToSphinxPath()
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
|
|
log.Tracef("Constructed per-hop payloads for payment_hash=%x: %v",
|
|
paymentHash[:], newLogClosure(func() string {
|
|
path := make([]sphinx.OnionHop, sphinxPath.TrueRouteLength())
|
|
for i := range path {
|
|
hopCopy := sphinxPath[i]
|
|
hopCopy.NodePub.Curve = nil
|
|
path[i] = hopCopy
|
|
}
|
|
return spew.Sdump(path)
|
|
}),
|
|
)
|
|
|
|
// Next generate the onion routing packet which allows us to perform
|
|
// privacy preserving source routing across the network.
|
|
sphinxPacket, err := sphinx.NewOnionPacket(
|
|
sphinxPath, sessionKey, paymentHash,
|
|
sphinx.DeterministicPacketFiller,
|
|
)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
|
|
// Finally, encode Sphinx packet using its wire representation to be
|
|
// included within the HTLC add packet.
|
|
var onionBlob bytes.Buffer
|
|
if err := sphinxPacket.Encode(&onionBlob); err != nil {
|
|
return nil, nil, err
|
|
}
|
|
|
|
log.Tracef("Generated sphinx packet: %v",
|
|
newLogClosure(func() string {
|
|
// We make a copy of the ephemeral key and unset the
|
|
// internal curve here in order to keep the logs from
|
|
// getting noisy.
|
|
key := *sphinxPacket.EphemeralKey
|
|
key.Curve = nil
|
|
packetCopy := *sphinxPacket
|
|
packetCopy.EphemeralKey = &key
|
|
return spew.Sdump(packetCopy)
|
|
}),
|
|
)
|
|
|
|
return onionBlob.Bytes(), &sphinx.Circuit{
|
|
SessionKey: sessionKey,
|
|
PaymentPath: sphinxPath.NodeKeys(),
|
|
}, nil
|
|
}
|
|
|
|
// LightningPayment describes a payment to be sent through the network to the
|
|
// final destination.
|
|
type LightningPayment struct {
|
|
// Target is the node in which the payment should be routed towards.
|
|
Target route.Vertex
|
|
|
|
// Amount is the value of the payment to send through the network in
|
|
// milli-satoshis.
|
|
Amount lnwire.MilliSatoshi
|
|
|
|
// FeeLimit is the maximum fee in millisatoshis that the payment should
|
|
// accept when sending it through the network. The payment will fail
|
|
// if there isn't a route with lower fees than this limit.
|
|
FeeLimit lnwire.MilliSatoshi
|
|
|
|
// CltvLimit is the maximum time lock that is allowed for attempts to
|
|
// complete this payment.
|
|
CltvLimit uint32
|
|
|
|
// PaymentHash is the r-hash value to use within the HTLC extended to
|
|
// the first hop.
|
|
PaymentHash [32]byte
|
|
|
|
// FinalCLTVDelta is the CTLV expiry delta to use for the _final_ hop
|
|
// in the route. This means that the final hop will have a CLTV delta
|
|
// of at least: currentHeight + FinalCLTVDelta.
|
|
FinalCLTVDelta uint16
|
|
|
|
// PayAttemptTimeout is a timeout value that we'll use to determine
|
|
// when we should should abandon the payment attempt after consecutive
|
|
// payment failure. This prevents us from attempting to send a payment
|
|
// indefinitely. A zero value means the payment will never time out.
|
|
//
|
|
// TODO(halseth): make wallclock time to allow resume after startup.
|
|
PayAttemptTimeout time.Duration
|
|
|
|
// RouteHints represents the different routing hints that can be used to
|
|
// assist a payment in reaching its destination successfully. These
|
|
// hints will act as intermediate hops along the route.
|
|
//
|
|
// NOTE: This is optional unless required by the payment. When providing
|
|
// multiple routes, ensure the hop hints within each route are chained
|
|
// together and sorted in forward order in order to reach the
|
|
// destination successfully.
|
|
RouteHints [][]zpay32.HopHint
|
|
|
|
// OutgoingChannelIDs is the list of channels that are allowed for the
|
|
// first hop. If nil, any channel may be used.
|
|
OutgoingChannelIDs []uint64
|
|
|
|
// LastHop is the pubkey of the last node before the final destination
|
|
// is reached. If nil, any node may be used.
|
|
LastHop *route.Vertex
|
|
|
|
// DestFeatures specifies the set of features we assume the final node
|
|
// has for pathfinding. Typically these will be taken directly from an
|
|
// invoice, but they can also be manually supplied or assumed by the
|
|
// sender. If a nil feature vector is provided, the router will try to
|
|
// fallback to the graph in order to load a feature vector for a node in
|
|
// the public graph.
|
|
DestFeatures *lnwire.FeatureVector
|
|
|
|
// PaymentAddr is the payment address specified by the receiver. This
|
|
// field should be a random 32-byte nonce presented in the receiver's
|
|
// invoice to prevent probing of the destination.
|
|
PaymentAddr *[32]byte
|
|
|
|
// PaymentRequest is an optional payment request that this payment is
|
|
// attempting to complete.
|
|
PaymentRequest []byte
|
|
|
|
// DestCustomRecords are TLV records that are to be sent to the final
|
|
// hop in the new onion payload format. If the destination does not
|
|
// understand this new onion payload format, then the payment will
|
|
// fail.
|
|
DestCustomRecords record.CustomSet
|
|
|
|
// MaxParts is the maximum number of partial payments that may be used
|
|
// to complete the full amount.
|
|
MaxParts uint32
|
|
}
|
|
|
|
// SendPayment attempts to send a payment as described within the passed
|
|
// LightningPayment. This function is blocking and will return either: when the
|
|
// payment is successful, or all candidates routes have been attempted and
|
|
// resulted in a failed payment. If the payment succeeds, then a non-nil Route
|
|
// will be returned which describes the path the successful payment traversed
|
|
// within the network to reach the destination. Additionally, the payment
|
|
// preimage will also be returned.
|
|
func (r *ChannelRouter) SendPayment(payment *LightningPayment) ([32]byte,
|
|
*route.Route, error) {
|
|
|
|
paySession, err := r.preparePayment(payment)
|
|
if err != nil {
|
|
return [32]byte{}, nil, err
|
|
}
|
|
|
|
log.Tracef("Dispatching SendPayment for lightning payment: %v",
|
|
spewPayment(payment))
|
|
|
|
// Since this is the first time this payment is being made, we pass nil
|
|
// for the existing attempt.
|
|
return r.sendPayment(
|
|
payment.Amount, payment.FeeLimit, payment.PaymentHash,
|
|
payment.PayAttemptTimeout, paySession,
|
|
)
|
|
}
|
|
|
|
// SendPaymentAsync is the non-blocking version of SendPayment. The payment
|
|
// result needs to be retrieved via the control tower.
|
|
func (r *ChannelRouter) SendPaymentAsync(payment *LightningPayment) error {
|
|
paySession, err := r.preparePayment(payment)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Since this is the first time this payment is being made, we pass nil
|
|
// for the existing attempt.
|
|
r.wg.Add(1)
|
|
go func() {
|
|
defer r.wg.Done()
|
|
|
|
log.Tracef("Dispatching SendPayment for lightning payment: %v",
|
|
spewPayment(payment))
|
|
|
|
_, _, err := r.sendPayment(
|
|
payment.Amount, payment.FeeLimit, payment.PaymentHash,
|
|
payment.PayAttemptTimeout, paySession,
|
|
)
|
|
if err != nil {
|
|
log.Errorf("Payment with hash %x failed: %v",
|
|
payment.PaymentHash, err)
|
|
}
|
|
}()
|
|
|
|
return nil
|
|
}
|
|
|
|
// spewPayment returns a log closures that provides a spewed string
|
|
// representation of the passed payment.
|
|
func spewPayment(payment *LightningPayment) logClosure {
|
|
return newLogClosure(func() string {
|
|
// Make a copy of the payment with a nilled Curve
|
|
// before spewing.
|
|
var routeHints [][]zpay32.HopHint
|
|
for _, routeHint := range payment.RouteHints {
|
|
var hopHints []zpay32.HopHint
|
|
for _, hopHint := range routeHint {
|
|
h := hopHint.Copy()
|
|
h.NodeID.Curve = nil
|
|
hopHints = append(hopHints, h)
|
|
}
|
|
routeHints = append(routeHints, hopHints)
|
|
}
|
|
p := *payment
|
|
p.RouteHints = routeHints
|
|
return spew.Sdump(p)
|
|
})
|
|
}
|
|
|
|
// preparePayment creates the payment session and registers the payment with the
|
|
// control tower.
|
|
func (r *ChannelRouter) preparePayment(payment *LightningPayment) (
|
|
PaymentSession, error) {
|
|
|
|
// Before starting the HTLC routing attempt, we'll create a fresh
|
|
// payment session which will report our errors back to mission
|
|
// control.
|
|
paySession, err := r.cfg.SessionSource.NewPaymentSession(payment)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Record this payment hash with the ControlTower, ensuring it is not
|
|
// already in-flight.
|
|
//
|
|
// TODO(roasbeef): store records as part of creation info?
|
|
info := &channeldb.PaymentCreationInfo{
|
|
PaymentHash: payment.PaymentHash,
|
|
Value: payment.Amount,
|
|
CreationTime: r.cfg.Clock.Now(),
|
|
PaymentRequest: payment.PaymentRequest,
|
|
}
|
|
|
|
err = r.cfg.Control.InitPayment(payment.PaymentHash, info)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return paySession, nil
|
|
}
|
|
|
|
// SendToRoute attempts to send a payment with the given hash through the
|
|
// provided route. This function is blocking and will return the attempt
|
|
// information as it is stored in the database. For a successful htlc, this
|
|
// information will contain the preimage. If an error occurs after the attempt
|
|
// was initiated, both return values will be non-nil.
|
|
func (r *ChannelRouter) SendToRoute(hash lntypes.Hash, rt *route.Route) (
|
|
*channeldb.HTLCAttempt, error) {
|
|
|
|
// Calculate amount paid to receiver.
|
|
amt := rt.ReceiverAmt()
|
|
|
|
// If this is meant as a MP payment shard, we set the amount
|
|
// for the creating info to the total amount of the payment.
|
|
finalHop := rt.Hops[len(rt.Hops)-1]
|
|
mpp := finalHop.MPP
|
|
if mpp != nil {
|
|
amt = mpp.TotalMsat()
|
|
}
|
|
|
|
// Record this payment hash with the ControlTower, ensuring it is not
|
|
// already in-flight.
|
|
info := &channeldb.PaymentCreationInfo{
|
|
PaymentHash: hash,
|
|
Value: amt,
|
|
CreationTime: r.cfg.Clock.Now(),
|
|
PaymentRequest: nil,
|
|
}
|
|
|
|
err := r.cfg.Control.InitPayment(hash, info)
|
|
switch {
|
|
// If this is an MPP attempt and the hash is already registered with
|
|
// the database, we can go on to launch the shard.
|
|
case err == channeldb.ErrPaymentInFlight && mpp != nil:
|
|
|
|
// Any other error is not tolerated.
|
|
case err != nil:
|
|
return nil, err
|
|
}
|
|
|
|
log.Tracef("Dispatching SendToRoute for hash %v: %v",
|
|
hash, newLogClosure(func() string {
|
|
return spew.Sdump(rt)
|
|
}),
|
|
)
|
|
|
|
// Launch a shard along the given route.
|
|
sh := &shardHandler{
|
|
router: r,
|
|
paymentHash: hash,
|
|
}
|
|
|
|
var shardError error
|
|
attempt, outcome, err := sh.launchShard(rt)
|
|
|
|
// With SendToRoute, it can happen that the route exceeds protocol
|
|
// constraints. Mark the payment as failed with an internal error.
|
|
if err == route.ErrMaxRouteHopsExceeded ||
|
|
err == sphinx.ErrMaxRoutingInfoSizeExceeded {
|
|
|
|
log.Debugf("Invalid route provided for payment %x: %v",
|
|
hash, err)
|
|
|
|
controlErr := r.cfg.Control.Fail(
|
|
hash, channeldb.FailureReasonError,
|
|
)
|
|
if controlErr != nil {
|
|
return nil, controlErr
|
|
}
|
|
}
|
|
|
|
// In any case, don't continue if there is an error.
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var htlcAttempt *channeldb.HTLCAttempt
|
|
switch {
|
|
// Failed to launch shard.
|
|
case outcome.err != nil:
|
|
shardError = outcome.err
|
|
htlcAttempt = outcome.attempt
|
|
|
|
// Shard successfully launched, wait for the result to be available.
|
|
default:
|
|
result, err := sh.collectResult(attempt)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// We got a successful result.
|
|
if result.err == nil {
|
|
return result.attempt, nil
|
|
}
|
|
|
|
// The shard failed, break switch to handle it.
|
|
shardError = result.err
|
|
htlcAttempt = result.attempt
|
|
}
|
|
|
|
// Since for SendToRoute we won't retry in case the shard fails, we'll
|
|
// mark the payment failed with the control tower immediately. Process
|
|
// the error to check if it maps into a terminal error code, if not use
|
|
// a generic NO_ROUTE error.
|
|
reason := r.processSendError(
|
|
attempt.AttemptID, &attempt.Route, shardError,
|
|
)
|
|
if reason == nil {
|
|
r := channeldb.FailureReasonNoRoute
|
|
reason = &r
|
|
}
|
|
|
|
err = r.cfg.Control.Fail(hash, *reason)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return htlcAttempt, shardError
|
|
}
|
|
|
|
// sendPayment attempts to send a payment to the passed payment hash. This
|
|
// function is blocking and will return either: when the payment is successful,
|
|
// or all candidates routes have been attempted and resulted in a failed
|
|
// payment. If the payment succeeds, then a non-nil Route will be returned
|
|
// which describes the path the successful payment traversed within the network
|
|
// to reach the destination. Additionally, the payment preimage will also be
|
|
// returned.
|
|
//
|
|
// The existing attempt argument should be set to nil if this is a payment that
|
|
// haven't had any payment attempt sent to the switch yet. If it has had an
|
|
// attempt already, it should be passed such that the result can be retrieved.
|
|
//
|
|
// This method relies on the ControlTower's internal payment state machine to
|
|
// carry out its execution. After restarts it is safe, and assumed, that the
|
|
// router will call this method for every payment still in-flight according to
|
|
// the ControlTower.
|
|
func (r *ChannelRouter) sendPayment(
|
|
totalAmt, feeLimit lnwire.MilliSatoshi, paymentHash lntypes.Hash,
|
|
timeout time.Duration,
|
|
paySession PaymentSession) ([32]byte, *route.Route, error) {
|
|
|
|
// We'll also fetch the current block height so we can properly
|
|
// calculate the required HTLC time locks within the route.
|
|
_, currentHeight, err := r.cfg.Chain.GetBestBlock()
|
|
if err != nil {
|
|
return [32]byte{}, nil, err
|
|
}
|
|
|
|
// Now set up a paymentLifecycle struct with these params, such that we
|
|
// can resume the payment from the current state.
|
|
p := &paymentLifecycle{
|
|
router: r,
|
|
totalAmount: totalAmt,
|
|
feeLimit: feeLimit,
|
|
paymentHash: paymentHash,
|
|
paySession: paySession,
|
|
currentHeight: currentHeight,
|
|
}
|
|
|
|
// If a timeout is specified, create a timeout channel. If no timeout is
|
|
// specified, the channel is left nil and will never abort the payment
|
|
// loop.
|
|
if timeout != 0 {
|
|
p.timeoutChan = time.After(timeout)
|
|
}
|
|
|
|
return p.resumePayment()
|
|
|
|
}
|
|
|
|
// tryApplyChannelUpdate tries to apply a channel update present in the failure
|
|
// message if any.
|
|
func (r *ChannelRouter) tryApplyChannelUpdate(rt *route.Route,
|
|
errorSourceIdx int, failure lnwire.FailureMessage) error {
|
|
|
|
// It makes no sense to apply our own channel updates.
|
|
if errorSourceIdx == 0 {
|
|
log.Errorf("Channel update of ourselves received")
|
|
|
|
return nil
|
|
}
|
|
|
|
// Extract channel update if the error contains one.
|
|
update := r.extractChannelUpdate(failure)
|
|
if update == nil {
|
|
return nil
|
|
}
|
|
|
|
// Parse pubkey to allow validation of the channel update. This should
|
|
// always succeed, otherwise there is something wrong in our
|
|
// implementation. Therefore return an error.
|
|
errVertex := rt.Hops[errorSourceIdx-1].PubKeyBytes
|
|
errSource, err := btcec.ParsePubKey(
|
|
errVertex[:], btcec.S256(),
|
|
)
|
|
if err != nil {
|
|
log.Errorf("Cannot parse pubkey: idx=%v, pubkey=%v",
|
|
errorSourceIdx, errVertex)
|
|
|
|
return err
|
|
}
|
|
|
|
// Apply channel update.
|
|
if !r.applyChannelUpdate(update, errSource) {
|
|
log.Debugf("Invalid channel update received: node=%v",
|
|
errVertex)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// processSendError analyzes the error for the payment attempt received from the
|
|
// switch and updates mission control and/or channel policies. Depending on the
|
|
// error type, this error is either the final outcome of the payment or we need
|
|
// to continue with an alternative route. This is indicated by the boolean
|
|
// return value.
|
|
func (r *ChannelRouter) processSendError(paymentID uint64, rt *route.Route,
|
|
sendErr error) *channeldb.FailureReason {
|
|
|
|
internalErrorReason := channeldb.FailureReasonError
|
|
|
|
reportFail := func(srcIdx *int,
|
|
msg lnwire.FailureMessage) *channeldb.FailureReason {
|
|
|
|
// Report outcome to mission control.
|
|
reason, err := r.cfg.MissionControl.ReportPaymentFail(
|
|
paymentID, rt, srcIdx, msg,
|
|
)
|
|
if err != nil {
|
|
log.Errorf("Error reporting payment result to mc: %v",
|
|
err)
|
|
|
|
return &internalErrorReason
|
|
}
|
|
|
|
return reason
|
|
}
|
|
|
|
if sendErr == htlcswitch.ErrUnreadableFailureMessage {
|
|
log.Tracef("Unreadable failure when sending htlc")
|
|
|
|
return reportFail(nil, nil)
|
|
}
|
|
|
|
// If the error is a ClearTextError, we have received a valid wire
|
|
// failure message, either from our own outgoing link or from a node
|
|
// down the route. If the error is not related to the propagation of
|
|
// our payment, we can stop trying because an internal error has
|
|
// occurred.
|
|
rtErr, ok := sendErr.(htlcswitch.ClearTextError)
|
|
if !ok {
|
|
return &internalErrorReason
|
|
}
|
|
|
|
// failureSourceIdx is the index of the node that the failure occurred
|
|
// at. If the ClearTextError received is not a ForwardingError the
|
|
// payment error occurred at our node, so we leave this value as 0
|
|
// to indicate that the failure occurred locally. If the error is a
|
|
// ForwardingError, it did not originate at our node, so we set
|
|
// failureSourceIdx to the index of the node where the failure occurred.
|
|
failureSourceIdx := 0
|
|
source, ok := rtErr.(*htlcswitch.ForwardingError)
|
|
if ok {
|
|
failureSourceIdx = source.FailureSourceIdx
|
|
}
|
|
|
|
// Extract the wire failure and apply channel update if it contains one.
|
|
// If we received an unknown failure message from a node along the
|
|
// route, the failure message will be nil.
|
|
failureMessage := rtErr.WireMessage()
|
|
if failureMessage != nil {
|
|
err := r.tryApplyChannelUpdate(
|
|
rt, failureSourceIdx, failureMessage,
|
|
)
|
|
if err != nil {
|
|
return &internalErrorReason
|
|
}
|
|
}
|
|
|
|
log.Tracef("Node=%v reported failure when sending htlc",
|
|
failureSourceIdx)
|
|
|
|
return reportFail(&failureSourceIdx, failureMessage)
|
|
}
|
|
|
|
// extractChannelUpdate examines the error and extracts the channel update.
|
|
func (r *ChannelRouter) extractChannelUpdate(
|
|
failure lnwire.FailureMessage) *lnwire.ChannelUpdate {
|
|
|
|
var update *lnwire.ChannelUpdate
|
|
switch onionErr := failure.(type) {
|
|
case *lnwire.FailExpiryTooSoon:
|
|
update = &onionErr.Update
|
|
case *lnwire.FailAmountBelowMinimum:
|
|
update = &onionErr.Update
|
|
case *lnwire.FailFeeInsufficient:
|
|
update = &onionErr.Update
|
|
case *lnwire.FailIncorrectCltvExpiry:
|
|
update = &onionErr.Update
|
|
case *lnwire.FailChannelDisabled:
|
|
update = &onionErr.Update
|
|
case *lnwire.FailTemporaryChannelFailure:
|
|
update = onionErr.Update
|
|
}
|
|
|
|
return update
|
|
}
|
|
|
|
// applyChannelUpdate validates a channel update and if valid, applies it to the
|
|
// database. It returns a bool indicating whether the updates was successful.
|
|
func (r *ChannelRouter) applyChannelUpdate(msg *lnwire.ChannelUpdate,
|
|
pubKey *btcec.PublicKey) bool {
|
|
|
|
ch, _, _, err := r.GetChannelByID(msg.ShortChannelID)
|
|
if err != nil {
|
|
log.Errorf("Unable to retrieve channel by id: %v", err)
|
|
return false
|
|
}
|
|
|
|
if err := ValidateChannelUpdateAnn(pubKey, ch.Capacity, msg); err != nil {
|
|
log.Errorf("Unable to validate channel update: %v", err)
|
|
return false
|
|
}
|
|
|
|
err = r.UpdateEdge(&channeldb.ChannelEdgePolicy{
|
|
SigBytes: msg.Signature.ToSignatureBytes(),
|
|
ChannelID: msg.ShortChannelID.ToUint64(),
|
|
LastUpdate: time.Unix(int64(msg.Timestamp), 0),
|
|
MessageFlags: msg.MessageFlags,
|
|
ChannelFlags: msg.ChannelFlags,
|
|
TimeLockDelta: msg.TimeLockDelta,
|
|
MinHTLC: msg.HtlcMinimumMsat,
|
|
MaxHTLC: msg.HtlcMaximumMsat,
|
|
FeeBaseMSat: lnwire.MilliSatoshi(msg.BaseFee),
|
|
FeeProportionalMillionths: lnwire.MilliSatoshi(msg.FeeRate),
|
|
})
|
|
if err != nil && !IsError(err, ErrIgnored, ErrOutdated) {
|
|
log.Errorf("Unable to apply channel update: %v", err)
|
|
return false
|
|
}
|
|
|
|
return true
|
|
}
|
|
|
|
// AddNode is used to add information about a node to the router database. If
|
|
// the node with this pubkey is not present in an existing channel, it will
|
|
// be ignored.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) AddNode(node *channeldb.LightningNode) error {
|
|
rMsg := &routingMsg{
|
|
msg: node,
|
|
err: make(chan error, 1),
|
|
}
|
|
|
|
select {
|
|
case r.networkUpdates <- rMsg:
|
|
select {
|
|
case err := <-rMsg.err:
|
|
return err
|
|
case <-r.quit:
|
|
return ErrRouterShuttingDown
|
|
}
|
|
case <-r.quit:
|
|
return ErrRouterShuttingDown
|
|
}
|
|
}
|
|
|
|
// AddEdge is used to add edge/channel to the topology of the router, after all
|
|
// information about channel will be gathered this edge/channel might be used
|
|
// in construction of payment path.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) AddEdge(edge *channeldb.ChannelEdgeInfo) error {
|
|
rMsg := &routingMsg{
|
|
msg: edge,
|
|
err: make(chan error, 1),
|
|
}
|
|
|
|
select {
|
|
case r.networkUpdates <- rMsg:
|
|
select {
|
|
case err := <-rMsg.err:
|
|
return err
|
|
case <-r.quit:
|
|
return ErrRouterShuttingDown
|
|
}
|
|
case <-r.quit:
|
|
return ErrRouterShuttingDown
|
|
}
|
|
}
|
|
|
|
// UpdateEdge is used to update edge information, without this message edge
|
|
// considered as not fully constructed.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) UpdateEdge(update *channeldb.ChannelEdgePolicy) error {
|
|
rMsg := &routingMsg{
|
|
msg: update,
|
|
err: make(chan error, 1),
|
|
}
|
|
|
|
select {
|
|
case r.networkUpdates <- rMsg:
|
|
select {
|
|
case err := <-rMsg.err:
|
|
return err
|
|
case <-r.quit:
|
|
return ErrRouterShuttingDown
|
|
}
|
|
case <-r.quit:
|
|
return ErrRouterShuttingDown
|
|
}
|
|
}
|
|
|
|
// CurrentBlockHeight returns the block height from POV of the router subsystem.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) CurrentBlockHeight() (uint32, error) {
|
|
_, height, err := r.cfg.Chain.GetBestBlock()
|
|
return uint32(height), err
|
|
}
|
|
|
|
// GetChannelByID return the channel by the channel id.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) GetChannelByID(chanID lnwire.ShortChannelID) (
|
|
*channeldb.ChannelEdgeInfo,
|
|
*channeldb.ChannelEdgePolicy,
|
|
*channeldb.ChannelEdgePolicy, error) {
|
|
|
|
return r.cfg.Graph.FetchChannelEdgesByID(chanID.ToUint64())
|
|
}
|
|
|
|
// FetchLightningNode attempts to look up a target node by its identity public
|
|
// key. channeldb.ErrGraphNodeNotFound is returned if the node doesn't exist
|
|
// within the graph.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) FetchLightningNode(node route.Vertex) (*channeldb.LightningNode, error) {
|
|
return r.cfg.Graph.FetchLightningNode(nil, node)
|
|
}
|
|
|
|
// ForEachNode is used to iterate over every node in router topology.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) ForEachNode(cb func(*channeldb.LightningNode) error) error {
|
|
return r.cfg.Graph.ForEachNode(func(_ kvdb.ReadTx, n *channeldb.LightningNode) error {
|
|
return cb(n)
|
|
})
|
|
}
|
|
|
|
// ForAllOutgoingChannels is used to iterate over all outgoing channels owned by
|
|
// the router.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) ForAllOutgoingChannels(cb func(*channeldb.ChannelEdgeInfo,
|
|
*channeldb.ChannelEdgePolicy) error) error {
|
|
|
|
return r.selfNode.ForEachChannel(nil, func(_ kvdb.ReadTx, c *channeldb.ChannelEdgeInfo,
|
|
e, _ *channeldb.ChannelEdgePolicy) error {
|
|
|
|
if e == nil {
|
|
return fmt.Errorf("channel from self node has no policy")
|
|
}
|
|
|
|
return cb(c, e)
|
|
})
|
|
}
|
|
|
|
// ForEachChannel is used to iterate over every known edge (channel) within our
|
|
// view of the channel graph.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) ForEachChannel(cb func(chanInfo *channeldb.ChannelEdgeInfo,
|
|
e1, e2 *channeldb.ChannelEdgePolicy) error) error {
|
|
|
|
return r.cfg.Graph.ForEachChannel(cb)
|
|
}
|
|
|
|
// AddProof updates the channel edge info with proof which is needed to
|
|
// properly announce the edge to the rest of the network.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) AddProof(chanID lnwire.ShortChannelID,
|
|
proof *channeldb.ChannelAuthProof) error {
|
|
|
|
info, _, _, err := r.cfg.Graph.FetchChannelEdgesByID(chanID.ToUint64())
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
info.AuthProof = proof
|
|
return r.cfg.Graph.UpdateChannelEdge(info)
|
|
}
|
|
|
|
// IsStaleNode returns true if the graph source has a node announcement for the
|
|
// target node with a more recent timestamp.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) IsStaleNode(node route.Vertex, timestamp time.Time) bool {
|
|
// If our attempt to assert that the node announcement is fresh fails,
|
|
// then we know that this is actually a stale announcement.
|
|
return r.assertNodeAnnFreshness(node, timestamp) != nil
|
|
}
|
|
|
|
// IsPublicNode determines whether the given vertex is seen as a public node in
|
|
// the graph from the graph's source node's point of view.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) IsPublicNode(node route.Vertex) (bool, error) {
|
|
return r.cfg.Graph.IsPublicNode(node)
|
|
}
|
|
|
|
// IsKnownEdge returns true if the graph source already knows of the passed
|
|
// channel ID either as a live or zombie edge.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) IsKnownEdge(chanID lnwire.ShortChannelID) bool {
|
|
_, _, exists, isZombie, _ := r.cfg.Graph.HasChannelEdge(chanID.ToUint64())
|
|
return exists || isZombie
|
|
}
|
|
|
|
// IsStaleEdgePolicy returns true if the graph soruce has a channel edge for
|
|
// the passed channel ID (and flags) that have a more recent timestamp.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) IsStaleEdgePolicy(chanID lnwire.ShortChannelID,
|
|
timestamp time.Time, flags lnwire.ChanUpdateChanFlags) bool {
|
|
|
|
edge1Timestamp, edge2Timestamp, exists, isZombie, err :=
|
|
r.cfg.Graph.HasChannelEdge(chanID.ToUint64())
|
|
if err != nil {
|
|
return false
|
|
|
|
}
|
|
|
|
// If we know of the edge as a zombie, then we'll make some additional
|
|
// checks to determine if the new policy is fresh.
|
|
if isZombie {
|
|
// When running with AssumeChannelValid, we also prune channels
|
|
// if both of their edges are disabled. We'll mark the new
|
|
// policy as stale if it remains disabled.
|
|
if r.cfg.AssumeChannelValid {
|
|
isDisabled := flags&lnwire.ChanUpdateDisabled ==
|
|
lnwire.ChanUpdateDisabled
|
|
if isDisabled {
|
|
return true
|
|
}
|
|
}
|
|
|
|
// Otherwise, we'll fall back to our usual ChannelPruneExpiry.
|
|
return time.Since(timestamp) > r.cfg.ChannelPruneExpiry
|
|
}
|
|
|
|
// If we don't know of the edge, then it means it's fresh (thus not
|
|
// stale).
|
|
if !exists {
|
|
return false
|
|
}
|
|
|
|
// As edges are directional edge node has a unique policy for the
|
|
// direction of the edge they control. Therefore we first check if we
|
|
// already have the most up to date information for that edge. If so,
|
|
// then we can exit early.
|
|
switch {
|
|
// A flag set of 0 indicates this is an announcement for the "first"
|
|
// node in the channel.
|
|
case flags&lnwire.ChanUpdateDirection == 0:
|
|
return !edge1Timestamp.Before(timestamp)
|
|
|
|
// Similarly, a flag set of 1 indicates this is an announcement for the
|
|
// "second" node in the channel.
|
|
case flags&lnwire.ChanUpdateDirection == 1:
|
|
return !edge2Timestamp.Before(timestamp)
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
// MarkEdgeLive clears an edge from our zombie index, deeming it as live.
|
|
//
|
|
// NOTE: This method is part of the ChannelGraphSource interface.
|
|
func (r *ChannelRouter) MarkEdgeLive(chanID lnwire.ShortChannelID) error {
|
|
return r.cfg.Graph.MarkEdgeLive(chanID.ToUint64())
|
|
}
|
|
|
|
// generateBandwidthHints is a helper function that's utilized the main
|
|
// findPath function in order to obtain hints from the lower layer w.r.t to the
|
|
// available bandwidth of edges on the network. Currently, we'll only obtain
|
|
// bandwidth hints for the edges we directly have open ourselves. Obtaining
|
|
// these hints allows us to reduce the number of extraneous attempts as we can
|
|
// skip channels that are inactive, or just don't have enough bandwidth to
|
|
// carry the payment.
|
|
func generateBandwidthHints(sourceNode *channeldb.LightningNode,
|
|
queryBandwidth func(*channeldb.ChannelEdgeInfo) lnwire.MilliSatoshi) (map[uint64]lnwire.MilliSatoshi, error) {
|
|
|
|
// First, we'll collect the set of outbound edges from the target
|
|
// source node.
|
|
var localChans []*channeldb.ChannelEdgeInfo
|
|
err := sourceNode.ForEachChannel(nil, func(tx kvdb.ReadTx,
|
|
edgeInfo *channeldb.ChannelEdgeInfo,
|
|
_, _ *channeldb.ChannelEdgePolicy) error {
|
|
|
|
localChans = append(localChans, edgeInfo)
|
|
return nil
|
|
})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Now that we have all of our outbound edges, we'll populate the set
|
|
// of bandwidth hints, querying the lower switch layer for the most up
|
|
// to date values.
|
|
bandwidthHints := make(map[uint64]lnwire.MilliSatoshi)
|
|
for _, localChan := range localChans {
|
|
bandwidthHints[localChan.ChannelID] = queryBandwidth(localChan)
|
|
}
|
|
|
|
return bandwidthHints, nil
|
|
}
|
|
|
|
// ErrNoChannel is returned when a route cannot be built because there are no
|
|
// channels that satisfy all requirements.
|
|
type ErrNoChannel struct {
|
|
position int
|
|
fromNode route.Vertex
|
|
}
|
|
|
|
// Error returns a human readable string describing the error.
|
|
func (e ErrNoChannel) Error() string {
|
|
return fmt.Sprintf("no matching outgoing channel available for "+
|
|
"node %v (%v)", e.position, e.fromNode)
|
|
}
|
|
|
|
// BuildRoute returns a fully specified route based on a list of pubkeys. If
|
|
// amount is nil, the minimum routable amount is used. To force a specific
|
|
// outgoing channel, use the outgoingChan parameter.
|
|
func (r *ChannelRouter) BuildRoute(amt *lnwire.MilliSatoshi,
|
|
hops []route.Vertex, outgoingChan *uint64,
|
|
finalCltvDelta int32) (*route.Route, error) {
|
|
|
|
log.Tracef("BuildRoute called: hopsCount=%v, amt=%v",
|
|
len(hops), amt)
|
|
|
|
var outgoingChans map[uint64]struct{}
|
|
if outgoingChan != nil {
|
|
outgoingChans = map[uint64]struct{}{
|
|
*outgoingChan: {},
|
|
}
|
|
}
|
|
|
|
// If no amount is specified, we need to build a route for the minimum
|
|
// amount that this route can carry.
|
|
useMinAmt := amt == nil
|
|
|
|
// We'll attempt to obtain a set of bandwidth hints that helps us select
|
|
// the best outgoing channel to use in case no outgoing channel is set.
|
|
bandwidthHints, err := generateBandwidthHints(
|
|
r.selfNode, r.cfg.QueryBandwidth,
|
|
)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Fetch the current block height outside the routing transaction, to
|
|
// prevent the rpc call blocking the database.
|
|
_, height, err := r.cfg.Chain.GetBestBlock()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Allocate a list that will contain the unified policies for this
|
|
// route.
|
|
edges := make([]*unifiedPolicy, len(hops))
|
|
|
|
var runningAmt lnwire.MilliSatoshi
|
|
if useMinAmt {
|
|
// For minimum amount routes, aim to deliver at least 1 msat to
|
|
// the destination. There are nodes in the wild that have a
|
|
// min_htlc channel policy of zero, which could lead to a zero
|
|
// amount payment being made.
|
|
runningAmt = 1
|
|
} else {
|
|
// If an amount is specified, we need to build a route that
|
|
// delivers exactly this amount to the final destination.
|
|
runningAmt = *amt
|
|
}
|
|
|
|
// Open a transaction to execute the graph queries in.
|
|
routingTx, err := newDbRoutingTx(r.cfg.Graph)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer func() {
|
|
err := routingTx.close()
|
|
if err != nil {
|
|
log.Errorf("Error closing db tx: %v", err)
|
|
}
|
|
}()
|
|
|
|
// Traverse hops backwards to accumulate fees in the running amounts.
|
|
source := r.selfNode.PubKeyBytes
|
|
for i := len(hops) - 1; i >= 0; i-- {
|
|
toNode := hops[i]
|
|
|
|
var fromNode route.Vertex
|
|
if i == 0 {
|
|
fromNode = source
|
|
} else {
|
|
fromNode = hops[i-1]
|
|
}
|
|
|
|
localChan := i == 0
|
|
|
|
// Build unified policies for this hop based on the channels
|
|
// known in the graph.
|
|
u := newUnifiedPolicies(source, toNode, outgoingChans)
|
|
|
|
err := u.addGraphPolicies(routingTx)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Exit if there are no channels.
|
|
unifiedPolicy, ok := u.policies[fromNode]
|
|
if !ok {
|
|
return nil, ErrNoChannel{
|
|
fromNode: fromNode,
|
|
position: i,
|
|
}
|
|
}
|
|
|
|
// If using min amt, increase amt if needed.
|
|
if useMinAmt {
|
|
min := unifiedPolicy.minAmt()
|
|
if min > runningAmt {
|
|
runningAmt = min
|
|
}
|
|
}
|
|
|
|
// Get a forwarding policy for the specific amount that we want
|
|
// to forward.
|
|
policy := unifiedPolicy.getPolicy(runningAmt, bandwidthHints)
|
|
if policy == nil {
|
|
return nil, ErrNoChannel{
|
|
fromNode: fromNode,
|
|
position: i,
|
|
}
|
|
}
|
|
|
|
// Add fee for this hop.
|
|
if !localChan {
|
|
runningAmt += policy.ComputeFee(runningAmt)
|
|
}
|
|
|
|
log.Tracef("Select channel %v at position %v", policy.ChannelID, i)
|
|
|
|
edges[i] = unifiedPolicy
|
|
}
|
|
|
|
// Now that we arrived at the start of the route and found out the route
|
|
// total amount, we make a forward pass. Because the amount may have
|
|
// been increased in the backward pass, fees need to be recalculated and
|
|
// amount ranges re-checked.
|
|
var pathEdges []*channeldb.ChannelEdgePolicy
|
|
receiverAmt := runningAmt
|
|
for i, edge := range edges {
|
|
policy := edge.getPolicy(receiverAmt, bandwidthHints)
|
|
if policy == nil {
|
|
return nil, ErrNoChannel{
|
|
fromNode: hops[i-1],
|
|
position: i,
|
|
}
|
|
}
|
|
|
|
if i > 0 {
|
|
// Decrease the amount to send while going forward.
|
|
receiverAmt -= policy.ComputeFeeFromIncoming(
|
|
receiverAmt,
|
|
)
|
|
}
|
|
|
|
pathEdges = append(pathEdges, policy)
|
|
}
|
|
|
|
// Build and return the final route.
|
|
return newRoute(
|
|
source, pathEdges, uint32(height),
|
|
finalHopParams{
|
|
amt: receiverAmt,
|
|
totalAmt: receiverAmt,
|
|
cltvDelta: uint16(finalCltvDelta),
|
|
records: nil,
|
|
},
|
|
)
|
|
}
|