2676 lines
88 KiB
Go
2676 lines
88 KiB
Go
package htlcswitch
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import (
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"bytes"
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"crypto/sha256"
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"fmt"
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prand "math/rand"
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"sync"
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"sync/atomic"
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"time"
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"github.com/btcsuite/btcd/chaincfg/chainhash"
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"github.com/davecgh/go-spew/spew"
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"github.com/go-errors/errors"
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/contractcourt"
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"github.com/lightningnetwork/lnd/htlcswitch/hodl"
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"github.com/lightningnetwork/lnd/lnpeer"
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"github.com/lightningnetwork/lnd/lnwallet"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/ticker"
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)
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func init() {
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prand.Seed(time.Now().UnixNano())
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}
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const (
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// expiryGraceDelta is a grace period that the timeout of incoming
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// HTLC's that pay directly to us (i.e we're the "exit node") must up
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// hold. We'll reject any HTLC's who's timeout minus this value is less
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// that or equal to the current block height. We require this in order
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// to ensure that if the extending party goes to the chain, then we'll
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// be able to claim the HTLC still.
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//
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// TODO(roasbeef): must be < default delta
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expiryGraceDelta = 2
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// DefaultMinLinkFeeUpdateTimeout represents the minimum interval in
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// which a link should propose to update its commitment fee rate.
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DefaultMinLinkFeeUpdateTimeout = 10 * time.Minute
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// DefaultMaxLinkFeeUpdateTimeout represents the maximum interval in
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// which a link should propose to update its commitment fee rate.
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DefaultMaxLinkFeeUpdateTimeout = 60 * time.Minute
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)
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// ForwardingPolicy describes the set of constraints that a given ChannelLink
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// is to adhere to when forwarding HTLC's. For each incoming HTLC, this set of
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// constraints will be consulted in order to ensure that adequate fees are
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// paid, and our time-lock parameters are respected. In the event that an
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// incoming HTLC violates any of these constraints, it is to be _rejected_ with
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// the error possibly carrying along a ChannelUpdate message that includes the
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// latest policy.
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type ForwardingPolicy struct {
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// MinHTLC is the smallest HTLC that is to be forwarded. This is
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// set when a channel is first opened, and will be static for the
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// lifetime of the channel.
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MinHTLC lnwire.MilliSatoshi
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// BaseFee is the base fee, expressed in milli-satoshi that must be
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// paid for each incoming HTLC. This field, combined with FeeRate is
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// used to compute the required fee for a given HTLC.
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BaseFee lnwire.MilliSatoshi
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// FeeRate is the fee rate, expressed in milli-satoshi that must be
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// paid for each incoming HTLC. This field combined with BaseFee is
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// used to compute the required fee for a given HTLC.
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FeeRate lnwire.MilliSatoshi
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// TimeLockDelta is the absolute time-lock value, expressed in blocks,
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// that will be subtracted from an incoming HTLC's timelock value to
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// create the time-lock value for the forwarded outgoing HTLC. The
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// following constraint MUST hold for an HTLC to be forwarded:
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//
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// * incomingHtlc.timeLock - timeLockDelta = fwdInfo.OutgoingCTLV
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//
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// where fwdInfo is the forwarding information extracted from the
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// per-hop payload of the incoming HTLC's onion packet.
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TimeLockDelta uint32
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// TODO(roasbeef): add fee module inside of switch
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}
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// ExpectedFee computes the expected fee for a given htlc amount. The value
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// returned from this function is to be used as a sanity check when forwarding
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// HTLC's to ensure that an incoming HTLC properly adheres to our propagated
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// forwarding policy.
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//
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// TODO(roasbeef): also add in current available channel bandwidth, inverse
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// func
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func ExpectedFee(f ForwardingPolicy,
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htlcAmt lnwire.MilliSatoshi) lnwire.MilliSatoshi {
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return f.BaseFee + (htlcAmt*f.FeeRate)/1000000
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}
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// ChannelLinkConfig defines the configuration for the channel link. ALL
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// elements within the configuration MUST be non-nil for channel link to carry
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// out its duties.
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type ChannelLinkConfig struct {
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// FwrdingPolicy is the initial forwarding policy to be used when
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// deciding whether to forwarding incoming HTLC's or not. This value
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// can be updated with subsequent calls to UpdateForwardingPolicy
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// targeted at a given ChannelLink concrete interface implementation.
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FwrdingPolicy ForwardingPolicy
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// Circuits provides restricted access to the switch's circuit map,
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// allowing the link to open and close circuits.
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Circuits CircuitModifier
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// Switch provides a reference to the HTLC switch, we only use this in
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// testing to access circuit operations not typically exposed by the
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// CircuitModifier.
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//
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// TODO(conner): remove after refactoring htlcswitch testing framework.
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Switch *Switch
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// ForwardPackets attempts to forward the batch of htlcs through the
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// switch. Any failed packets will be returned to the provided
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// ChannelLink.
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ForwardPackets func(...*htlcPacket) chan error
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// DecodeHopIterators facilitates batched decoding of HTLC Sphinx onion
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// blobs, which are then used to inform how to forward an HTLC.
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//
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// NOTE: This function assumes the same set of readers and preimages
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// are always presented for the same identifier.
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DecodeHopIterators func([]byte, []DecodeHopIteratorRequest) (
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[]DecodeHopIteratorResponse, error)
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// ExtractErrorEncrypter function is responsible for decoding HTLC
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// Sphinx onion blob, and creating onion failure obfuscator.
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ExtractErrorEncrypter ErrorEncrypterExtracter
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// FetchLastChannelUpdate retrieves the latest routing policy for a
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// target channel. This channel will typically be the outgoing channel
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// specified when we receive an incoming HTLC. This will be used to
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// provide payment senders our latest policy when sending encrypted
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// error messages.
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FetchLastChannelUpdate func(lnwire.ShortChannelID) (*lnwire.ChannelUpdate, error)
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// Peer is a lightning network node with which we have the channel link
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// opened.
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Peer lnpeer.Peer
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// Registry is a sub-system which responsible for managing the invoices
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// in thread-safe manner.
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Registry InvoiceDatabase
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// PreimageCache is a global witness beacon that houses any new
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// preimages discovered by other links. We'll use this to add new
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// witnesses that we discover which will notify any sub-systems
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// subscribed to new events.
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PreimageCache contractcourt.WitnessBeacon
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// OnChannelFailure is a function closure that we'll call if the
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// channel failed for some reason. Depending on the severity of the
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// error, the closure potentially must force close this channel and
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// disconnect the peer.
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//
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// NOTE: The method must return in order for the ChannelLink to be able
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// to shut down properly.
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OnChannelFailure func(lnwire.ChannelID, lnwire.ShortChannelID,
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LinkFailureError)
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// UpdateContractSignals is a function closure that we'll use to update
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// outside sub-systems with the latest signals for our inner Lightning
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// channel. These signals will notify the caller when the channel has
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// been closed, or when the set of active HTLC's is updated.
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UpdateContractSignals func(*contractcourt.ContractSignals) error
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// ChainEvents is an active subscription to the chain watcher for this
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// channel to be notified of any on-chain activity related to this
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// channel.
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ChainEvents *contractcourt.ChainEventSubscription
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// FeeEstimator is an instance of a live fee estimator which will be
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// used to dynamically regulate the current fee of the commitment
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// transaction to ensure timely confirmation.
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FeeEstimator lnwallet.FeeEstimator
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// DebugHTLC should be turned on if you want all HTLCs sent to a node
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// with the debug htlc R-Hash are immediately settled in the next
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// available state transition.
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DebugHTLC bool
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// hodl.Mask is a bitvector composed of hodl.Flags, specifying breakpoints
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// for HTLC forwarding internal to the switch.
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//
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// NOTE: This should only be used for testing, and should only be used
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// simultaneously with DebugHTLC.
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HodlMask hodl.Mask
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// SyncStates is used to indicate that we need send the channel
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// reestablishment message to the remote peer. It should be done if our
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// clients have been restarted, or remote peer have been reconnected.
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SyncStates bool
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// BatchTicker is the ticker that determines the interval that we'll
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// use to check the batch to see if there're any updates we should
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// flush out. By batching updates into a single commit, we attempt to
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// increase throughput by maximizing the number of updates coalesced
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// into a single commit.
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BatchTicker ticker.Ticker
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// FwdPkgGCTicker is the ticker determining the frequency at which
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// garbage collection of forwarding packages occurs. We use a
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// time-based approach, as opposed to block epochs, as to not hinder
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// syncing.
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FwdPkgGCTicker ticker.Ticker
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// BatchSize is the max size of a batch of updates done to the link
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// before we do a state update.
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BatchSize uint32
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// UnsafeReplay will cause a link to replay the adds in its latest
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// commitment txn after the link is restarted. This should only be used
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// in testing, it is here to ensure the sphinx replay detection on the
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// receiving node is persistent.
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UnsafeReplay bool
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// MinFeeUpdateTimeout and MaxFeeUpdateTimeout represent the timeout
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// interval bounds in which a link will propose to update its commitment
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// fee rate. A random timeout will be selected between these values.
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MinFeeUpdateTimeout time.Duration
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MaxFeeUpdateTimeout time.Duration
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}
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// channelLink is the service which drives a channel's commitment update
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// state-machine. In the event that an HTLC needs to be propagated to another
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// link, the forward handler from config is used which sends HTLC to the
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// switch. Additionally, the link encapsulate logic of commitment protocol
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// message ordering and updates.
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type channelLink struct {
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// The following fields are only meant to be used *atomically*
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started int32
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shutdown int32
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// failed should be set to true in case a link error happens, making
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// sure we don't process any more updates.
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failed bool
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// batchCounter is the number of updates which we received from remote
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// side, but not include in commitment transaction yet and plus the
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// current number of settles that have been sent, but not yet committed
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// to the commitment.
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//
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// TODO(andrew.shvv) remove after we add additional BatchNumber()
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// method in state machine.
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batchCounter uint32
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// keystoneBatch represents a volatile list of keystones that must be
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// written before attempting to sign the next commitment txn. These
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// represent all the HTLC's forwarded to the link from the switch. Once
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// we lock them into our outgoing commitment, then the circuit has a
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// keystone, and is fully opened.
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keystoneBatch []Keystone
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// openedCircuits is the set of all payment circuits that will be open
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// once we make our next commitment. After making the commitment we'll
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// ACK all these from our mailbox to ensure that they don't get
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// re-delivered if we reconnect.
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openedCircuits []CircuitKey
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// closedCircuits is the set of all payment circuits that will be
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// closed once we make our next commitment. After taking the commitment
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// we'll ACK all these to ensure that they don't get re-delivered if we
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// reconnect.
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closedCircuits []CircuitKey
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// channel is a lightning network channel to which we apply htlc
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// updates.
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channel *lnwallet.LightningChannel
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// shortChanID is the most up to date short channel ID for the link.
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shortChanID lnwire.ShortChannelID
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// cfg is a structure which carries all dependable fields/handlers
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// which may affect behaviour of the service.
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cfg ChannelLinkConfig
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// overflowQueue is used to store the htlc add updates which haven't
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// been processed because of the commitment transaction overflow.
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overflowQueue *packetQueue
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// startMailBox directs whether or not to start the mailbox when
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// starting the link. It may have already been started by the switch.
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startMailBox bool
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// mailBox is the main interface between the outside world and the
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// link. All incoming messages will be sent over this mailBox. Messages
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// include new updates from our connected peer, and new packets to be
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// forwarded sent by the switch.
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mailBox MailBox
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// upstream is a channel that new messages sent from the remote peer to
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// the local peer will be sent across.
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upstream chan lnwire.Message
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// downstream is a channel in which new multi-hop HTLC's to be
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// forwarded will be sent across. Messages from this channel are sent
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// by the HTLC switch.
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downstream chan *htlcPacket
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// htlcUpdates is a channel that we'll use to update outside
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// sub-systems with the latest set of active HTLC's on our channel.
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htlcUpdates chan []channeldb.HTLC
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// logCommitTimer is a timer which is sent upon if we go an interval
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// without receiving/sending a commitment update. It's role is to
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// ensure both chains converge to identical state in a timely manner.
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//
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// TODO(roasbeef): timer should be >> then RTT
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logCommitTimer *time.Timer
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logCommitTick <-chan time.Time
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// updateFeeTimer is the timer responsible for updating the link's
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// commitment fee every time it fires.
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updateFeeTimer *time.Timer
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sync.RWMutex
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wg sync.WaitGroup
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quit chan struct{}
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}
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// NewChannelLink creates a new instance of a ChannelLink given a configuration
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// and active channel that will be used to verify/apply updates to.
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func NewChannelLink(cfg ChannelLinkConfig,
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channel *lnwallet.LightningChannel) ChannelLink {
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return &channelLink{
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cfg: cfg,
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channel: channel,
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shortChanID: channel.ShortChanID(),
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// TODO(roasbeef): just do reserve here?
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logCommitTimer: time.NewTimer(300 * time.Millisecond),
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overflowQueue: newPacketQueue(lnwallet.MaxHTLCNumber / 2),
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htlcUpdates: make(chan []channeldb.HTLC),
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quit: make(chan struct{}),
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}
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}
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// A compile time check to ensure channelLink implements the ChannelLink
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// interface.
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var _ ChannelLink = (*channelLink)(nil)
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// Start starts all helper goroutines required for the operation of the channel
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// link.
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//
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// NOTE: Part of the ChannelLink interface.
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func (l *channelLink) Start() error {
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if !atomic.CompareAndSwapInt32(&l.started, 0, 1) {
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err := errors.Errorf("channel link(%v): already started", l)
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log.Warn(err)
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return err
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}
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log.Infof("ChannelLink(%v) is starting", l)
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// Before we start the link, we'll update the ChainArbitrator with the
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// set of new channel signals for this channel.
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//
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// TODO(roasbeef): split goroutines within channel arb to avoid
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go func() {
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err := l.cfg.UpdateContractSignals(&contractcourt.ContractSignals{
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HtlcUpdates: l.htlcUpdates,
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ShortChanID: l.channel.ShortChanID(),
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})
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if err != nil {
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log.Errorf("Unable to update signals for "+
|
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"ChannelLink(%v)", l)
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}
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}()
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|
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l.mailBox.ResetMessages()
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l.overflowQueue.Start()
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|
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// Before launching the htlcManager messages, revert any circuits that
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// were marked open in the switch's circuit map, but did not make it
|
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// into a commitment txn. We use the next local htlc index as the cut
|
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// off point, since all indexes below that are committed. This action
|
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// is only performed if the link's final short channel ID has been
|
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// assigned, otherwise we would try to trim the htlcs belonging to the
|
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// all-zero, sourceHop ID.
|
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if l.ShortChanID() != sourceHop {
|
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localHtlcIndex, err := l.channel.NextLocalHtlcIndex()
|
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if err != nil {
|
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return fmt.Errorf("unable to retrieve next local "+
|
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"htlc index: %v", err)
|
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}
|
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|
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// NOTE: This is automatically done by the switch when it
|
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// starts up, but is necessary to prevent inconsistencies in
|
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// the case that the link flaps. This is a result of a link's
|
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// life-cycle being shorter than that of the switch.
|
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chanID := l.ShortChanID()
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err = l.cfg.Circuits.TrimOpenCircuits(chanID, localHtlcIndex)
|
|
if err != nil {
|
|
return fmt.Errorf("unable to trim circuits above "+
|
|
"local htlc index %d: %v", localHtlcIndex, err)
|
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}
|
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}
|
|
|
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l.updateFeeTimer = time.NewTimer(l.randomFeeUpdateTimeout())
|
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|
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l.wg.Add(1)
|
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go l.htlcManager()
|
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|
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return nil
|
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}
|
|
|
|
// Stop gracefully stops all active helper goroutines, then waits until they've
|
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// exited.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) Stop() {
|
|
if !atomic.CompareAndSwapInt32(&l.shutdown, 0, 1) {
|
|
log.Warnf("channel link(%v): already stopped", l)
|
|
return
|
|
}
|
|
|
|
log.Infof("ChannelLink(%v) is stopping", l)
|
|
|
|
if l.cfg.ChainEvents.Cancel != nil {
|
|
l.cfg.ChainEvents.Cancel()
|
|
}
|
|
|
|
l.updateFeeTimer.Stop()
|
|
l.channel.Stop()
|
|
l.overflowQueue.Stop()
|
|
|
|
close(l.quit)
|
|
l.wg.Wait()
|
|
}
|
|
|
|
// WaitForShutdown blocks until the link finishes shutting down, which includes
|
|
// termination of all dependent goroutines.
|
|
func (l *channelLink) WaitForShutdown() {
|
|
l.wg.Wait()
|
|
}
|
|
|
|
// EligibleToForward returns a bool indicating if the channel is able to
|
|
// actively accept requests to forward HTLC's. We're able to forward HTLC's if
|
|
// we know the remote party's next revocation point. Otherwise, we can't
|
|
// initiate new channel state. We also require that the short channel ID not be
|
|
// the all-zero source ID, meaning that the channel has had its ID finalized.
|
|
func (l *channelLink) EligibleToForward() bool {
|
|
return l.channel.RemoteNextRevocation() != nil &&
|
|
l.ShortChanID() != sourceHop
|
|
}
|
|
|
|
// sampleNetworkFee samples the current fee rate on the network to get into the
|
|
// chain in a timely manner. The returned value is expressed in fee-per-kw, as
|
|
// this is the native rate used when computing the fee for commitment
|
|
// transactions, and the second-level HTLC transactions.
|
|
func (l *channelLink) sampleNetworkFee() (lnwallet.SatPerKWeight, error) {
|
|
// We'll first query for the sat/kw recommended to be confirmed within 3
|
|
// blocks.
|
|
feePerKw, err := l.cfg.FeeEstimator.EstimateFeePerKW(3)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
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log.Debugf("ChannelLink(%v): sampled fee rate for 3 block conf: %v "+
|
|
"sat/kw", l, int64(feePerKw))
|
|
|
|
return feePerKw, nil
|
|
}
|
|
|
|
// shouldAdjustCommitFee returns true if we should update our commitment fee to
|
|
// match that of the network fee. We'll only update our commitment fee if the
|
|
// network fee is +/- 10% to our network fee.
|
|
func shouldAdjustCommitFee(netFee, chanFee lnwallet.SatPerKWeight) bool {
|
|
switch {
|
|
// If the network fee is greater than the commitment fee, then we'll
|
|
// switch to it if it's at least 10% greater than the commit fee.
|
|
case netFee > chanFee && netFee >= (chanFee+(chanFee*10)/100):
|
|
return true
|
|
|
|
// If the network fee is less than our commitment fee, then we'll
|
|
// switch to it if it's at least 10% less than the commitment fee.
|
|
case netFee < chanFee && netFee <= (chanFee-(chanFee*10)/100):
|
|
return true
|
|
|
|
// Otherwise, we won't modify our fee.
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// syncChanState attempts to synchronize channel states with the remote party.
|
|
// This method is to be called upon reconnection after the initial funding
|
|
// flow. We'll compare out commitment chains with the remote party, and re-send
|
|
// either a danging commit signature, a revocation, or both.
|
|
func (l *channelLink) syncChanStates() error {
|
|
log.Infof("Attempting to re-resynchronize ChannelPoint(%v)",
|
|
l.channel.ChannelPoint())
|
|
|
|
// First, we'll generate our ChanSync message to send to the other
|
|
// side. Based on this message, the remote party will decide if they
|
|
// need to retransmit any data or not.
|
|
localChanSyncMsg, err := l.channel.ChanSyncMsg()
|
|
if err != nil {
|
|
return fmt.Errorf("unable to generate chan sync message for "+
|
|
"ChannelPoint(%v)", l.channel.ChannelPoint())
|
|
}
|
|
if err := l.cfg.Peer.SendMessage(false, localChanSyncMsg); err != nil {
|
|
return fmt.Errorf("Unable to send chan sync message for "+
|
|
"ChannelPoint(%v)", l.channel.ChannelPoint())
|
|
}
|
|
|
|
var msgsToReSend []lnwire.Message
|
|
|
|
// Next, we'll wait to receive the ChanSync message with a timeout
|
|
// period. The first message sent MUST be the ChanSync message,
|
|
// otherwise, we'll terminate the connection.
|
|
chanSyncDeadline := time.After(time.Second * 30)
|
|
select {
|
|
case msg := <-l.upstream:
|
|
remoteChanSyncMsg, ok := msg.(*lnwire.ChannelReestablish)
|
|
if !ok {
|
|
return fmt.Errorf("first message sent to sync "+
|
|
"should be ChannelReestablish, instead "+
|
|
"received: %T", msg)
|
|
}
|
|
|
|
// If the remote party indicates that they think we haven't
|
|
// done any state updates yet, then we'll retransmit the
|
|
// funding locked message first. We do this, as at this point
|
|
// we can't be sure if they've really received the
|
|
// FundingLocked message.
|
|
if remoteChanSyncMsg.NextLocalCommitHeight == 1 &&
|
|
localChanSyncMsg.NextLocalCommitHeight == 1 &&
|
|
!l.channel.IsPending() {
|
|
|
|
log.Infof("ChannelPoint(%v): resending "+
|
|
"FundingLocked message to peer",
|
|
l.channel.ChannelPoint())
|
|
|
|
nextRevocation, err := l.channel.NextRevocationKey()
|
|
if err != nil {
|
|
return fmt.Errorf("unable to create next "+
|
|
"revocation: %v", err)
|
|
}
|
|
|
|
fundingLockedMsg := lnwire.NewFundingLocked(
|
|
l.ChanID(), nextRevocation,
|
|
)
|
|
err = l.cfg.Peer.SendMessage(false, fundingLockedMsg)
|
|
if err != nil {
|
|
return fmt.Errorf("unable to re-send "+
|
|
"FundingLocked: %v", err)
|
|
}
|
|
}
|
|
|
|
// In any case, we'll then process their ChanSync message.
|
|
log.Infof("Received re-establishment message from remote side "+
|
|
"for channel(%v)", l.channel.ChannelPoint())
|
|
|
|
var (
|
|
openedCircuits []CircuitKey
|
|
closedCircuits []CircuitKey
|
|
)
|
|
|
|
// We've just received a ChanSync message from the remote
|
|
// party, so we'll process the message in order to determine
|
|
// if we need to re-transmit any messages to the remote party.
|
|
msgsToReSend, openedCircuits, closedCircuits, err =
|
|
l.channel.ProcessChanSyncMsg(remoteChanSyncMsg)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Repopulate any identifiers for circuits that may have been
|
|
// opened or unclosed. This may happen if we needed to
|
|
// retransmit a commitment signature message.
|
|
l.openedCircuits = openedCircuits
|
|
l.closedCircuits = closedCircuits
|
|
|
|
// Ensure that all packets have been have been removed from the
|
|
// link's mailbox.
|
|
if err := l.ackDownStreamPackets(true); err != nil {
|
|
return err
|
|
}
|
|
|
|
if len(msgsToReSend) > 0 {
|
|
log.Infof("Sending %v updates to synchronize the "+
|
|
"state for ChannelPoint(%v)", len(msgsToReSend),
|
|
l.channel.ChannelPoint())
|
|
}
|
|
|
|
// If we have any messages to retransmit, we'll do so
|
|
// immediately so we return to a synchronized state as soon as
|
|
// possible.
|
|
for _, msg := range msgsToReSend {
|
|
l.cfg.Peer.SendMessage(false, msg)
|
|
}
|
|
|
|
case <-l.quit:
|
|
return ErrLinkShuttingDown
|
|
|
|
case <-chanSyncDeadline:
|
|
return fmt.Errorf("didn't receive ChannelReestablish before " +
|
|
"deadline")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// resolveFwdPkgs loads any forwarding packages for this link from disk, and
|
|
// reprocesses them in order. The primary goal is to make sure that any HTLCs
|
|
// we previously received are reinstated in memory, and forwarded to the switch
|
|
// if necessary. After a restart, this will also delete any previously
|
|
// completed packages.
|
|
func (l *channelLink) resolveFwdPkgs() error {
|
|
fwdPkgs, err := l.channel.LoadFwdPkgs()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
l.debugf("loaded %d fwd pks", len(fwdPkgs))
|
|
|
|
var needUpdate bool
|
|
for _, fwdPkg := range fwdPkgs {
|
|
hasUpdate, err := l.resolveFwdPkg(fwdPkg)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
needUpdate = needUpdate || hasUpdate
|
|
}
|
|
|
|
// If any of our reprocessing steps require an update to the commitment
|
|
// txn, we initiate a state transition to capture all relevant changes.
|
|
if needUpdate {
|
|
return l.updateCommitTx()
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// resolveFwdPkg interprets the FwdState of the provided package, either
|
|
// reprocesses any outstanding htlcs in the package, or performs garbage
|
|
// collection on the package.
|
|
func (l *channelLink) resolveFwdPkg(fwdPkg *channeldb.FwdPkg) (bool, error) {
|
|
// Remove any completed packages to clear up space.
|
|
if fwdPkg.State == channeldb.FwdStateCompleted {
|
|
l.debugf("removing completed fwd pkg for height=%d",
|
|
fwdPkg.Height)
|
|
|
|
err := l.channel.RemoveFwdPkg(fwdPkg.Height)
|
|
if err != nil {
|
|
l.errorf("unable to remove fwd pkg for height=%d: %v",
|
|
fwdPkg.Height, err)
|
|
return false, err
|
|
}
|
|
}
|
|
|
|
// Otherwise this is either a new package or one has gone through
|
|
// processing, but contains htlcs that need to be restored in memory.
|
|
// We replay this forwarding package to make sure our local mem state
|
|
// is resurrected, we mimic any original responses back to the remote
|
|
// party, and re-forward the relevant HTLCs to the switch.
|
|
|
|
// If the package is fully acked but not completed, it must still have
|
|
// settles and fails to propagate.
|
|
if !fwdPkg.SettleFailFilter.IsFull() {
|
|
settleFails := lnwallet.PayDescsFromRemoteLogUpdates(
|
|
fwdPkg.Source, fwdPkg.Height, fwdPkg.SettleFails,
|
|
)
|
|
l.processRemoteSettleFails(fwdPkg, settleFails)
|
|
}
|
|
|
|
// Finally, replay *ALL ADDS* in this forwarding package. The
|
|
// downstream logic is able to filter out any duplicates, but we must
|
|
// shove the entire, original set of adds down the pipeline so that the
|
|
// batch of adds presented to the sphinx router does not ever change.
|
|
var needUpdate bool
|
|
if !fwdPkg.AckFilter.IsFull() {
|
|
adds := lnwallet.PayDescsFromRemoteLogUpdates(
|
|
fwdPkg.Source, fwdPkg.Height, fwdPkg.Adds,
|
|
)
|
|
needUpdate = l.processRemoteAdds(fwdPkg, adds)
|
|
|
|
// If the link failed during processing the adds, we must
|
|
// return to ensure we won't attempted to update the state
|
|
// further.
|
|
if l.failed {
|
|
return false, fmt.Errorf("link failed while " +
|
|
"processing remote adds")
|
|
}
|
|
}
|
|
|
|
return needUpdate, nil
|
|
}
|
|
|
|
// fwdPkgGarbager periodically reads all forwarding packages from disk and
|
|
// removes those that can be discarded. It is safe to do this entirely in the
|
|
// background, since all state is coordinated on disk. This also ensures the
|
|
// link can continue to process messages and interleave database accesses.
|
|
//
|
|
// NOTE: This MUST be run as a goroutine.
|
|
func (l *channelLink) fwdPkgGarbager() {
|
|
defer l.wg.Done()
|
|
|
|
l.cfg.FwdPkgGCTicker.Resume()
|
|
defer l.cfg.FwdPkgGCTicker.Stop()
|
|
|
|
for {
|
|
select {
|
|
case <-l.cfg.FwdPkgGCTicker.Ticks():
|
|
fwdPkgs, err := l.channel.LoadFwdPkgs()
|
|
if err != nil {
|
|
l.warnf("unable to load fwdpkgs for gc: %v", err)
|
|
continue
|
|
}
|
|
|
|
// TODO(conner): batch removal of forward packages.
|
|
for _, fwdPkg := range fwdPkgs {
|
|
if fwdPkg.State != channeldb.FwdStateCompleted {
|
|
continue
|
|
}
|
|
|
|
err = l.channel.RemoveFwdPkg(fwdPkg.Height)
|
|
if err != nil {
|
|
l.warnf("unable to remove fwd pkg "+
|
|
"for height=%d: %v",
|
|
fwdPkg.Height, err)
|
|
}
|
|
}
|
|
case <-l.quit:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// htlcManager is the primary goroutine which drives a channel's commitment
|
|
// update state-machine in response to messages received via several channels.
|
|
// This goroutine reads messages from the upstream (remote) peer, and also from
|
|
// downstream channel managed by the channel link. In the event that an htlc
|
|
// needs to be forwarded, then send-only forward handler is used which sends
|
|
// htlc packets to the switch. Additionally, the this goroutine handles acting
|
|
// upon all timeouts for any active HTLCs, manages the channel's revocation
|
|
// window, and also the htlc trickle queue+timer for this active channels.
|
|
//
|
|
// NOTE: This MUST be run as a goroutine.
|
|
func (l *channelLink) htlcManager() {
|
|
defer func() {
|
|
l.cfg.BatchTicker.Stop()
|
|
l.wg.Done()
|
|
log.Infof("ChannelLink(%v) has exited", l)
|
|
}()
|
|
|
|
log.Infof("HTLC manager for ChannelPoint(%v) started, "+
|
|
"bandwidth=%v", l.channel.ChannelPoint(), l.Bandwidth())
|
|
|
|
// TODO(roasbeef): need to call wipe chan whenever D/C?
|
|
|
|
// If this isn't the first time that this channel link has been
|
|
// created, then we'll need to check to see if we need to
|
|
// re-synchronize state with the remote peer. settledHtlcs is a map of
|
|
// HTLC's that we re-settled as part of the channel state sync.
|
|
if l.cfg.SyncStates {
|
|
err := l.syncChanStates()
|
|
if err != nil {
|
|
switch {
|
|
case err == ErrLinkShuttingDown:
|
|
log.Debugf("unable to sync channel states, " +
|
|
"link is shutting down")
|
|
return
|
|
|
|
// We failed syncing the commit chains, probably
|
|
// because the remote has lost state. We should force
|
|
// close the channel.
|
|
// TODO(halseth): store sent chanSync message to
|
|
// database, such that it can be resent to peer in case
|
|
// it tries to sync the channel again.
|
|
case err == lnwallet.ErrCommitSyncRemoteDataLoss:
|
|
fallthrough
|
|
|
|
// The remote sent us an invalid last commit secret, we
|
|
// should force close the channel.
|
|
// TODO(halseth): and permanently ban the peer?
|
|
case err == lnwallet.ErrInvalidLastCommitSecret:
|
|
fallthrough
|
|
|
|
// The remote sent us a commit point different from
|
|
// what they sent us before.
|
|
// TODO(halseth): ban peer?
|
|
case err == lnwallet.ErrInvalidLocalUnrevokedCommitPoint:
|
|
l.fail(
|
|
LinkFailureError{
|
|
code: ErrSyncError,
|
|
ForceClose: true,
|
|
},
|
|
"unable to synchronize channel "+
|
|
"states: %v", err,
|
|
)
|
|
return
|
|
|
|
// We have lost state and cannot safely force close the
|
|
// channel. Fail the channel and wait for the remote to
|
|
// hopefully force close it. The remote has sent us its
|
|
// latest unrevoked commitment point, that we stored in
|
|
// the database, that we can use to retrieve the funds
|
|
// when the remote closes the channel.
|
|
// TODO(halseth): mark this, such that we prevent
|
|
// channel from being force closed by the user or
|
|
// contractcourt etc.
|
|
case err == lnwallet.ErrCommitSyncLocalDataLoss:
|
|
|
|
// We determined the commit chains were not possible to
|
|
// sync. We cautiously fail the channel, but don't
|
|
// force close.
|
|
// TODO(halseth): can we safely force close in any
|
|
// cases where this error is returned?
|
|
case err == lnwallet.ErrCannotSyncCommitChains:
|
|
|
|
// Other, unspecified error.
|
|
default:
|
|
}
|
|
|
|
l.fail(
|
|
LinkFailureError{
|
|
code: ErrSyncError,
|
|
ForceClose: false,
|
|
},
|
|
"unable to synchronize channel "+
|
|
"states: %v", err,
|
|
)
|
|
return
|
|
}
|
|
}
|
|
|
|
// With the channel states synced, we now reset the mailbox to ensure
|
|
// we start processing all unacked packets in order. This is done here
|
|
// to ensure that all acknowledgments that occur during channel
|
|
// resynchronization have taken affect, causing us only to pull unacked
|
|
// packets after starting to read from the downstream mailbox.
|
|
l.mailBox.ResetPackets()
|
|
|
|
// After cleaning up any memory pertaining to incoming packets, we now
|
|
// replay our forwarding packages to handle any htlcs that can be
|
|
// processed locally, or need to be forwarded out to the switch.
|
|
if err := l.resolveFwdPkgs(); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to resolve fwd pkgs: %v", err)
|
|
return
|
|
}
|
|
|
|
// With our link's in-memory state fully reconstructed, spawn a
|
|
// goroutine to manage the reclamation of disk space occupied by
|
|
// completed forwarding packages.
|
|
l.wg.Add(1)
|
|
go l.fwdPkgGarbager()
|
|
|
|
out:
|
|
for {
|
|
// We must always check if we failed at some point processing
|
|
// the last update before processing the next.
|
|
if l.failed {
|
|
l.errorf("link failed, exiting htlcManager")
|
|
break out
|
|
}
|
|
|
|
select {
|
|
// Our update fee timer has fired, so we'll check the network
|
|
// fee to see if we should adjust our commitment fee.
|
|
case <-l.updateFeeTimer.C:
|
|
l.updateFeeTimer.Reset(l.randomFeeUpdateTimeout())
|
|
|
|
// If we're not the initiator of the channel, don't we
|
|
// don't control the fees, so we can ignore this.
|
|
if !l.channel.IsInitiator() {
|
|
continue
|
|
}
|
|
|
|
// If we are the initiator, then we'll sample the
|
|
// current fee rate to get into the chain within 3
|
|
// blocks.
|
|
feePerKw, err := l.sampleNetworkFee()
|
|
if err != nil {
|
|
log.Errorf("unable to sample network fee: %v", err)
|
|
continue
|
|
}
|
|
|
|
// We'll check to see if we should update the fee rate
|
|
// based on our current set fee rate.
|
|
commitFee := l.channel.CommitFeeRate()
|
|
if !shouldAdjustCommitFee(feePerKw, commitFee) {
|
|
continue
|
|
}
|
|
|
|
// If we do, then we'll send a new UpdateFee message to
|
|
// the remote party, to be locked in with a new update.
|
|
if err := l.updateChannelFee(feePerKw); err != nil {
|
|
log.Errorf("unable to update fee rate: %v", err)
|
|
continue
|
|
}
|
|
|
|
// The underlying channel has notified us of a unilateral close
|
|
// carried out by the remote peer. In the case of such an
|
|
// event, we'll wipe the channel state from the peer, and mark
|
|
// the contract as fully settled. Afterwards we can exit.
|
|
//
|
|
// TODO(roasbeef): add force closure? also breach?
|
|
case <-l.cfg.ChainEvents.RemoteUnilateralClosure:
|
|
log.Warnf("Remote peer has closed ChannelPoint(%v) on-chain",
|
|
l.channel.ChannelPoint())
|
|
|
|
// TODO(roasbeef): remove all together
|
|
go func() {
|
|
chanPoint := l.channel.ChannelPoint()
|
|
err := l.cfg.Peer.WipeChannel(chanPoint)
|
|
if err != nil {
|
|
log.Errorf("unable to wipe channel %v", err)
|
|
}
|
|
}()
|
|
|
|
break out
|
|
|
|
case <-l.logCommitTick:
|
|
// If we haven't sent or received a new commitment
|
|
// update in some time, check to see if we have any
|
|
// pending updates we need to commit due to our
|
|
// commitment chains being desynchronized.
|
|
if l.channel.FullySynced() {
|
|
continue
|
|
}
|
|
|
|
if err := l.updateCommitTx(); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to update commitment: %v", err)
|
|
break out
|
|
}
|
|
|
|
case <-l.cfg.BatchTicker.Ticks():
|
|
// If the current batch is empty, then we have no work
|
|
// here. We also disable the batch ticker from waking up
|
|
// the htlcManager while the batch is empty.
|
|
if l.batchCounter == 0 {
|
|
l.cfg.BatchTicker.Pause()
|
|
continue
|
|
}
|
|
|
|
// Otherwise, attempt to extend the remote commitment
|
|
// chain including all the currently pending entries.
|
|
// If the send was unsuccessful, then abandon the
|
|
// update, waiting for the revocation window to open
|
|
// up.
|
|
if err := l.updateCommitTx(); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to update commitment: %v", err)
|
|
break out
|
|
}
|
|
|
|
// A packet that previously overflowed the commitment
|
|
// transaction is now eligible for processing once again. So
|
|
// we'll attempt to re-process the packet in order to allow it
|
|
// to continue propagating within the network.
|
|
case packet := <-l.overflowQueue.outgoingPkts:
|
|
msg := packet.htlc.(*lnwire.UpdateAddHTLC)
|
|
log.Tracef("Reprocessing downstream add update "+
|
|
"with payment hash(%x)", msg.PaymentHash[:])
|
|
|
|
l.handleDownStreamPkt(packet, true)
|
|
|
|
// If the downstream packet resulted in a non-empty
|
|
// batch, reinstate the batch ticker so that it can be
|
|
// cleared.
|
|
if l.batchCounter > 0 {
|
|
l.cfg.BatchTicker.Resume()
|
|
}
|
|
|
|
// A message from the switch was just received. This indicates
|
|
// that the link is an intermediate hop in a multi-hop HTLC
|
|
// circuit.
|
|
case pkt := <-l.downstream:
|
|
// If we have non empty processing queue then we'll add
|
|
// this to the overflow rather than processing it
|
|
// directly. Once an active HTLC is either settled or
|
|
// failed, then we'll free up a new slot.
|
|
htlc, ok := pkt.htlc.(*lnwire.UpdateAddHTLC)
|
|
if ok && l.overflowQueue.Length() != 0 {
|
|
log.Infof("Downstream htlc add update with "+
|
|
"payment hash(%x) have been added to "+
|
|
"reprocessing queue, batch_size=%v",
|
|
htlc.PaymentHash[:],
|
|
l.batchCounter)
|
|
|
|
l.overflowQueue.AddPkt(pkt)
|
|
continue
|
|
}
|
|
|
|
l.handleDownStreamPkt(pkt, false)
|
|
|
|
// If the downstream packet resulted in a non-empty
|
|
// batch, reinstate the batch ticker so that it can be
|
|
// cleared.
|
|
if l.batchCounter > 0 {
|
|
l.cfg.BatchTicker.Resume()
|
|
}
|
|
|
|
// A message from the connected peer was just received. This
|
|
// indicates that we have a new incoming HTLC, either directly
|
|
// for us, or part of a multi-hop HTLC circuit.
|
|
case msg := <-l.upstream:
|
|
l.handleUpstreamMsg(msg)
|
|
|
|
case <-l.quit:
|
|
break out
|
|
}
|
|
}
|
|
}
|
|
|
|
// randomFeeUpdateTimeout returns a random timeout between the bounds defined
|
|
// within the link's configuration that will be used to determine when the link
|
|
// should propose an update to its commitment fee rate.
|
|
func (l *channelLink) randomFeeUpdateTimeout() time.Duration {
|
|
lower := int64(l.cfg.MinFeeUpdateTimeout)
|
|
upper := int64(l.cfg.MaxFeeUpdateTimeout)
|
|
return time.Duration(prand.Int63n(upper-lower) + lower)
|
|
}
|
|
|
|
// handleDownStreamPkt processes an HTLC packet sent from the downstream HTLC
|
|
// Switch. Possible messages sent by the switch include requests to forward new
|
|
// HTLCs, timeout previously cleared HTLCs, and finally to settle currently
|
|
// cleared HTLCs with the upstream peer.
|
|
//
|
|
// TODO(roasbeef): add sync ntfn to ensure switch always has consistent view?
|
|
func (l *channelLink) handleDownStreamPkt(pkt *htlcPacket, isReProcess bool) {
|
|
var isSettle bool
|
|
switch htlc := pkt.htlc.(type) {
|
|
case *lnwire.UpdateAddHTLC:
|
|
// If hodl.AddOutgoing mode is active, we exit early to simulate
|
|
// arbitrary delays between the switch adding an ADD to the
|
|
// mailbox, and the HTLC being added to the commitment state.
|
|
if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.AddOutgoing) {
|
|
l.warnf(hodl.AddOutgoing.Warning())
|
|
return
|
|
}
|
|
|
|
// A new payment has been initiated via the downstream channel,
|
|
// so we add the new HTLC to our local log, then update the
|
|
// commitment chains.
|
|
htlc.ChanID = l.ChanID()
|
|
openCircuitRef := pkt.inKey()
|
|
index, err := l.channel.AddHTLC(htlc, &openCircuitRef)
|
|
if err != nil {
|
|
switch err {
|
|
|
|
// The channels spare bandwidth is fully allocated, so
|
|
// we'll put this HTLC into the overflow queue.
|
|
case lnwallet.ErrMaxHTLCNumber:
|
|
l.infof("Downstream htlc add update with "+
|
|
"payment hash(%x) have been added to "+
|
|
"reprocessing queue, batch: %v",
|
|
htlc.PaymentHash[:],
|
|
l.batchCounter)
|
|
|
|
l.overflowQueue.AddPkt(pkt)
|
|
return
|
|
|
|
// The HTLC was unable to be added to the state
|
|
// machine, as a result, we'll signal the switch to
|
|
// cancel the pending payment.
|
|
default:
|
|
l.warnf("Unable to handle downstream add HTLC: %v", err)
|
|
|
|
var (
|
|
localFailure = false
|
|
reason lnwire.OpaqueReason
|
|
)
|
|
|
|
var failure lnwire.FailureMessage
|
|
update, err := l.cfg.FetchLastChannelUpdate(
|
|
l.ShortChanID(),
|
|
)
|
|
if err != nil {
|
|
failure = &lnwire.FailTemporaryNodeFailure{}
|
|
} else {
|
|
failure = lnwire.NewTemporaryChannelFailure(
|
|
update,
|
|
)
|
|
}
|
|
|
|
// Encrypt the error back to the source unless
|
|
// the payment was generated locally.
|
|
if pkt.obfuscator == nil {
|
|
var b bytes.Buffer
|
|
err := lnwire.EncodeFailure(&b, failure, 0)
|
|
if err != nil {
|
|
l.errorf("unable to encode failure: %v", err)
|
|
return
|
|
}
|
|
reason = lnwire.OpaqueReason(b.Bytes())
|
|
localFailure = true
|
|
} else {
|
|
var err error
|
|
reason, err = pkt.obfuscator.EncryptFirstHop(failure)
|
|
if err != nil {
|
|
l.errorf("unable to obfuscate error: %v", err)
|
|
return
|
|
}
|
|
}
|
|
|
|
failPkt := &htlcPacket{
|
|
incomingChanID: pkt.incomingChanID,
|
|
incomingHTLCID: pkt.incomingHTLCID,
|
|
circuit: pkt.circuit,
|
|
sourceRef: pkt.sourceRef,
|
|
hasSource: true,
|
|
localFailure: localFailure,
|
|
htlc: &lnwire.UpdateFailHTLC{
|
|
Reason: reason,
|
|
},
|
|
}
|
|
|
|
go l.forwardBatch(failPkt)
|
|
|
|
// Remove this packet from the link's mailbox,
|
|
// this prevents it from being reprocessed if
|
|
// the link restarts and resets it mailbox. If
|
|
// this response doesn't make it back to the
|
|
// originating link, it will be rejected upon
|
|
// attempting to reforward the Add to the
|
|
// switch, since the circuit was never fully
|
|
// opened, and the forwarding package shows it
|
|
// as unacknowledged.
|
|
l.mailBox.AckPacket(pkt.inKey())
|
|
|
|
return
|
|
}
|
|
}
|
|
|
|
l.tracef("Received downstream htlc: payment_hash=%x, "+
|
|
"local_log_index=%v, batch_size=%v",
|
|
htlc.PaymentHash[:], index, l.batchCounter+1)
|
|
|
|
pkt.outgoingChanID = l.ShortChanID()
|
|
pkt.outgoingHTLCID = index
|
|
htlc.ID = index
|
|
|
|
l.debugf("Queueing keystone of ADD open circuit: %s->%s",
|
|
pkt.inKey(), pkt.outKey())
|
|
|
|
l.openedCircuits = append(l.openedCircuits, pkt.inKey())
|
|
l.keystoneBatch = append(l.keystoneBatch, pkt.keystone())
|
|
|
|
l.cfg.Peer.SendMessage(false, htlc)
|
|
|
|
case *lnwire.UpdateFulfillHTLC:
|
|
// If hodl.SettleOutgoing mode is active, we exit early to
|
|
// simulate arbitrary delays between the switch adding the
|
|
// SETTLE to the mailbox, and the HTLC being added to the
|
|
// commitment state.
|
|
if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.SettleOutgoing) {
|
|
l.warnf(hodl.SettleOutgoing.Warning())
|
|
return
|
|
}
|
|
|
|
// An HTLC we forward to the switch has just settled somewhere
|
|
// upstream. Therefore we settle the HTLC within the our local
|
|
// state machine.
|
|
closedCircuitRef := pkt.inKey()
|
|
if err := l.channel.SettleHTLC(
|
|
htlc.PaymentPreimage,
|
|
pkt.incomingHTLCID,
|
|
pkt.sourceRef,
|
|
pkt.destRef,
|
|
&closedCircuitRef,
|
|
); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to settle incoming HTLC: %v", err)
|
|
return
|
|
}
|
|
|
|
l.debugf("Queueing removal of SETTLE closed circuit: %s->%s",
|
|
pkt.inKey(), pkt.outKey())
|
|
|
|
l.closedCircuits = append(l.closedCircuits, pkt.inKey())
|
|
|
|
// With the HTLC settled, we'll need to populate the wire
|
|
// message to target the specific channel and HTLC to be
|
|
// cancelled.
|
|
htlc.ChanID = l.ChanID()
|
|
htlc.ID = pkt.incomingHTLCID
|
|
|
|
// Then we send the HTLC settle message to the connected peer
|
|
// so we can continue the propagation of the settle message.
|
|
l.cfg.Peer.SendMessage(false, htlc)
|
|
isSettle = true
|
|
|
|
case *lnwire.UpdateFailHTLC:
|
|
// If hodl.FailOutgoing mode is active, we exit early to
|
|
// simulate arbitrary delays between the switch adding a FAIL to
|
|
// the mailbox, and the HTLC being added to the commitment
|
|
// state.
|
|
if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.FailOutgoing) {
|
|
l.warnf(hodl.FailOutgoing.Warning())
|
|
return
|
|
}
|
|
|
|
// An HTLC cancellation has been triggered somewhere upstream,
|
|
// we'll remove then HTLC from our local state machine.
|
|
closedCircuitRef := pkt.inKey()
|
|
if err := l.channel.FailHTLC(
|
|
pkt.incomingHTLCID,
|
|
htlc.Reason,
|
|
pkt.sourceRef,
|
|
pkt.destRef,
|
|
&closedCircuitRef,
|
|
); err != nil {
|
|
log.Errorf("unable to cancel HTLC: %v", err)
|
|
return
|
|
}
|
|
|
|
l.debugf("Queueing removal of FAIL closed circuit: %s->%s",
|
|
pkt.inKey(), pkt.outKey())
|
|
|
|
l.closedCircuits = append(l.closedCircuits, pkt.inKey())
|
|
|
|
// With the HTLC removed, we'll need to populate the wire
|
|
// message to target the specific channel and HTLC to be
|
|
// cancelled. The "Reason" field will have already been set
|
|
// within the switch.
|
|
htlc.ChanID = l.ChanID()
|
|
htlc.ID = pkt.incomingHTLCID
|
|
|
|
// Finally, we send the HTLC message to the peer which
|
|
// initially created the HTLC.
|
|
l.cfg.Peer.SendMessage(false, htlc)
|
|
isSettle = true
|
|
}
|
|
|
|
l.batchCounter++
|
|
|
|
// If this newly added update exceeds the min batch size for adds, or
|
|
// this is a settle request, then initiate an update.
|
|
if l.batchCounter >= l.cfg.BatchSize || isSettle {
|
|
if err := l.updateCommitTx(); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to update commitment: %v", err)
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// handleUpstreamMsg processes wire messages related to commitment state
|
|
// updates from the upstream peer. The upstream peer is the peer whom we have a
|
|
// direct channel with, updating our respective commitment chains.
|
|
func (l *channelLink) handleUpstreamMsg(msg lnwire.Message) {
|
|
switch msg := msg.(type) {
|
|
|
|
case *lnwire.UpdateAddHTLC:
|
|
// We just received an add request from an upstream peer, so we
|
|
// add it to our state machine, then add the HTLC to our
|
|
// "settle" list in the event that we know the preimage.
|
|
index, err := l.channel.ReceiveHTLC(msg)
|
|
if err != nil {
|
|
l.fail(LinkFailureError{code: ErrInvalidUpdate},
|
|
"unable to handle upstream add HTLC: %v", err)
|
|
return
|
|
}
|
|
|
|
l.tracef("Receive upstream htlc with payment hash(%x), "+
|
|
"assigning index: %v", msg.PaymentHash[:], index)
|
|
|
|
case *lnwire.UpdateFulfillHTLC:
|
|
pre := msg.PaymentPreimage
|
|
idx := msg.ID
|
|
if err := l.channel.ReceiveHTLCSettle(pre, idx); err != nil {
|
|
l.fail(
|
|
LinkFailureError{
|
|
code: ErrInvalidUpdate,
|
|
ForceClose: true,
|
|
},
|
|
"unable to handle upstream settle HTLC: %v", err,
|
|
)
|
|
return
|
|
}
|
|
|
|
// TODO(roasbeef): pipeline to switch
|
|
|
|
// As we've learned of a new preimage for the first time, we'll
|
|
// add it to our preimage cache. By doing this, we ensure
|
|
// any contested contracts watched by any on-chain arbitrators
|
|
// can now sweep this HTLC on-chain.
|
|
go func() {
|
|
err := l.cfg.PreimageCache.AddPreimage(pre[:])
|
|
if err != nil {
|
|
l.errorf("unable to add preimage=%x to "+
|
|
"cache", pre[:])
|
|
}
|
|
}()
|
|
|
|
case *lnwire.UpdateFailMalformedHTLC:
|
|
// Convert the failure type encoded within the HTLC fail
|
|
// message to the proper generic lnwire error code.
|
|
var failure lnwire.FailureMessage
|
|
switch msg.FailureCode {
|
|
case lnwire.CodeInvalidOnionVersion:
|
|
failure = &lnwire.FailInvalidOnionVersion{
|
|
OnionSHA256: msg.ShaOnionBlob,
|
|
}
|
|
case lnwire.CodeInvalidOnionHmac:
|
|
failure = &lnwire.FailInvalidOnionHmac{
|
|
OnionSHA256: msg.ShaOnionBlob,
|
|
}
|
|
|
|
case lnwire.CodeInvalidOnionKey:
|
|
failure = &lnwire.FailInvalidOnionKey{
|
|
OnionSHA256: msg.ShaOnionBlob,
|
|
}
|
|
default:
|
|
log.Errorf("Unknown failure code: %v", msg.FailureCode)
|
|
failure = &lnwire.FailTemporaryChannelFailure{}
|
|
}
|
|
|
|
// With the error parsed, we'll convert the into it's opaque
|
|
// form.
|
|
var b bytes.Buffer
|
|
if err := lnwire.EncodeFailure(&b, failure, 0); err != nil {
|
|
l.errorf("unable to encode malformed error: %v", err)
|
|
return
|
|
}
|
|
|
|
// If remote side have been unable to parse the onion blob we
|
|
// have sent to it, than we should transform the malformed HTLC
|
|
// message to the usual HTLC fail message.
|
|
err := l.channel.ReceiveFailHTLC(msg.ID, b.Bytes())
|
|
if err != nil {
|
|
l.fail(LinkFailureError{code: ErrInvalidUpdate},
|
|
"unable to handle upstream fail HTLC: %v", err)
|
|
return
|
|
}
|
|
|
|
case *lnwire.UpdateFailHTLC:
|
|
idx := msg.ID
|
|
err := l.channel.ReceiveFailHTLC(idx, msg.Reason[:])
|
|
if err != nil {
|
|
l.fail(LinkFailureError{code: ErrInvalidUpdate},
|
|
"unable to handle upstream fail HTLC: %v", err)
|
|
return
|
|
}
|
|
|
|
case *lnwire.CommitSig:
|
|
// We just received a new updates to our local commitment
|
|
// chain, validate this new commitment, closing the link if
|
|
// invalid.
|
|
err := l.channel.ReceiveNewCommitment(msg.CommitSig, msg.HtlcSigs)
|
|
if err != nil {
|
|
// If we were unable to reconstruct their proposed
|
|
// commitment, then we'll examine the type of error. If
|
|
// it's an InvalidCommitSigError, then we'll send a
|
|
// direct error.
|
|
var sendData []byte
|
|
switch err.(type) {
|
|
case *lnwallet.InvalidCommitSigError:
|
|
sendData = []byte(err.Error())
|
|
case *lnwallet.InvalidHtlcSigError:
|
|
sendData = []byte(err.Error())
|
|
}
|
|
l.fail(
|
|
LinkFailureError{
|
|
code: ErrInvalidCommitment,
|
|
ForceClose: true,
|
|
SendData: sendData,
|
|
},
|
|
"ChannelPoint(%v): unable to accept new "+
|
|
"commitment: %v",
|
|
l.channel.ChannelPoint(), err,
|
|
)
|
|
return
|
|
}
|
|
|
|
// As we've just accepted a new state, we'll now
|
|
// immediately send the remote peer a revocation for our prior
|
|
// state.
|
|
nextRevocation, currentHtlcs, err := l.channel.RevokeCurrentCommitment()
|
|
if err != nil {
|
|
log.Errorf("unable to revoke commitment: %v", err)
|
|
return
|
|
}
|
|
l.cfg.Peer.SendMessage(false, nextRevocation)
|
|
|
|
// Since we just revoked our commitment, we may have a new set
|
|
// of HTLC's on our commitment, so we'll send them over our
|
|
// HTLC update channel so any callers can be notified.
|
|
select {
|
|
case l.htlcUpdates <- currentHtlcs:
|
|
case <-l.quit:
|
|
return
|
|
}
|
|
|
|
// As we've just received a commitment signature, we'll
|
|
// re-start the log commit timer to wake up the main processing
|
|
// loop to check if we need to send a commitment signature as
|
|
// we owe one.
|
|
//
|
|
// TODO(roasbeef): instead after revocation?
|
|
if !l.logCommitTimer.Stop() {
|
|
select {
|
|
case <-l.logCommitTimer.C:
|
|
default:
|
|
}
|
|
}
|
|
l.logCommitTimer.Reset(300 * time.Millisecond)
|
|
l.logCommitTick = l.logCommitTimer.C
|
|
|
|
// If both commitment chains are fully synced from our PoV,
|
|
// then we don't need to reply with a signature as both sides
|
|
// already have a commitment with the latest accepted.
|
|
if l.channel.FullySynced() {
|
|
return
|
|
}
|
|
|
|
// Otherwise, the remote party initiated the state transition,
|
|
// so we'll reply with a signature to provide them with their
|
|
// version of the latest commitment.
|
|
if err := l.updateCommitTx(); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to update commitment: %v", err)
|
|
return
|
|
}
|
|
|
|
case *lnwire.RevokeAndAck:
|
|
// We've received a revocation from the remote chain, if valid,
|
|
// this moves the remote chain forward, and expands our
|
|
// revocation window.
|
|
fwdPkg, adds, settleFails, err := l.channel.ReceiveRevocation(msg)
|
|
if err != nil {
|
|
// TODO(halseth): force close?
|
|
l.fail(LinkFailureError{code: ErrInvalidRevocation},
|
|
"unable to accept revocation: %v", err)
|
|
return
|
|
}
|
|
|
|
l.processRemoteSettleFails(fwdPkg, settleFails)
|
|
needUpdate := l.processRemoteAdds(fwdPkg, adds)
|
|
|
|
// If the link failed during processing the adds, we must
|
|
// return to ensure we won't attempted to update the state
|
|
// further.
|
|
if l.failed {
|
|
return
|
|
}
|
|
|
|
if needUpdate {
|
|
if err := l.updateCommitTx(); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to update commitment: %v", err)
|
|
return
|
|
}
|
|
}
|
|
|
|
case *lnwire.UpdateFee:
|
|
// We received fee update from peer. If we are the initiator we
|
|
// will fail the channel, if not we will apply the update.
|
|
fee := lnwallet.SatPerKWeight(msg.FeePerKw)
|
|
if err := l.channel.ReceiveUpdateFee(fee); err != nil {
|
|
l.fail(LinkFailureError{code: ErrInvalidUpdate},
|
|
"error receiving fee update: %v", err)
|
|
return
|
|
}
|
|
case *lnwire.Error:
|
|
// Error received from remote, MUST fail channel, but should
|
|
// only print the contents of the error message if all
|
|
// characters are printable ASCII.
|
|
errMsg := "non-ascii data"
|
|
if isASCII(msg.Data) {
|
|
errMsg = string(msg.Data)
|
|
}
|
|
l.fail(LinkFailureError{code: ErrRemoteError},
|
|
"ChannelPoint(%v): received error from peer: %v",
|
|
l.channel.ChannelPoint(), errMsg)
|
|
default:
|
|
log.Warnf("ChannelPoint(%v): received unknown message of type %T",
|
|
l.channel.ChannelPoint(), msg)
|
|
}
|
|
|
|
}
|
|
|
|
// ackDownStreamPackets is responsible for removing htlcs from a link's mailbox
|
|
// for packets delivered from server, and cleaning up any circuits closed by
|
|
// signing a previous commitment txn. This method ensures that the circuits are
|
|
// removed from the circuit map before removing them from the link's mailbox,
|
|
// otherwise it could be possible for some circuit to be missed if this link
|
|
// flaps.
|
|
//
|
|
// The `forgive` flag allows this method to tolerate restarts, and ignores
|
|
// errors that could be caused by a previous circuit deletion. Under normal
|
|
// operation, this is set to false so that we would fail the link if we were
|
|
// unable to remove a circuit.
|
|
func (l *channelLink) ackDownStreamPackets(forgive bool) error {
|
|
// First, remove the downstream Add packets that were included in the
|
|
// previous commitment signature. This will prevent the Adds from being
|
|
// replayed if this link disconnects.
|
|
for _, inKey := range l.openedCircuits {
|
|
// In order to test the sphinx replay logic of the remote
|
|
// party, unsafe replay does not acknowledge the packets from
|
|
// the mailbox. We can then force a replay of any Add packets
|
|
// held in memory by disconnecting and reconnecting the link.
|
|
if l.cfg.UnsafeReplay {
|
|
continue
|
|
}
|
|
|
|
l.debugf("removing Add packet %s from mailbox", inKey)
|
|
l.mailBox.AckPacket(inKey)
|
|
}
|
|
|
|
// Now, we will delete all circuits closed by the previous commitment
|
|
// signature, which is the result of downstream Settle/Fail packets. We
|
|
// batch them here to ensure circuits are closed atomically and for
|
|
// performance.
|
|
err := l.cfg.Circuits.DeleteCircuits(l.closedCircuits...)
|
|
switch err {
|
|
case nil:
|
|
// Successful deletion.
|
|
|
|
case ErrUnknownCircuit:
|
|
if forgive {
|
|
// After a restart, we may have already removed this
|
|
// circuit. Since it shouldn't be possible for a
|
|
// circuit to be closed by different htlcs, we assume
|
|
// this error signals that the whole batch was
|
|
// successfully removed.
|
|
l.warnf("forgiving unknown circuit error after " +
|
|
"attempting deletion, circuit was probably " +
|
|
"removed before shutting down.")
|
|
break
|
|
}
|
|
|
|
return err
|
|
|
|
default:
|
|
l.errorf("unable to delete %d circuits: %v",
|
|
len(l.closedCircuits), err)
|
|
return err
|
|
}
|
|
|
|
// With the circuits removed from memory and disk, we now ack any
|
|
// Settle/Fails in the mailbox to ensure they do not get redelivered
|
|
// after startup. If forgive is enabled and we've reached this point,
|
|
// the circuits must have been removed at some point, so it is now safe
|
|
// to un-queue the corresponding Settle/Fails.
|
|
for _, inKey := range l.closedCircuits {
|
|
l.debugf("removing Fail/Settle packet %s from mailbox", inKey)
|
|
l.mailBox.AckPacket(inKey)
|
|
}
|
|
|
|
// Lastly, reset our buffers to be empty while keeping any acquired
|
|
// growth in the backing array.
|
|
l.openedCircuits = l.openedCircuits[:0]
|
|
l.closedCircuits = l.closedCircuits[:0]
|
|
|
|
return nil
|
|
}
|
|
|
|
// updateCommitTx signs, then sends an update to the remote peer adding a new
|
|
// commitment to their commitment chain which includes all the latest updates
|
|
// we've received+processed up to this point.
|
|
func (l *channelLink) updateCommitTx() error {
|
|
// Preemptively write all pending keystones to disk, just in case the
|
|
// HTLCs we have in memory are included in the subsequent attempt to
|
|
// sign a commitment state.
|
|
err := l.cfg.Circuits.OpenCircuits(l.keystoneBatch...)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Reset the batch, but keep the backing buffer to avoid reallocating.
|
|
l.keystoneBatch = l.keystoneBatch[:0]
|
|
|
|
// If hodl.Commit mode is active, we will refrain from attempting to
|
|
// commit any in-memory modifications to the channel state. Exiting here
|
|
// permits testing of either the switch or link's ability to trim
|
|
// circuits that have been opened, but unsuccessfully committed.
|
|
if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.Commit) {
|
|
l.warnf(hodl.Commit.Warning())
|
|
return nil
|
|
}
|
|
|
|
theirCommitSig, htlcSigs, err := l.channel.SignNextCommitment()
|
|
if err == lnwallet.ErrNoWindow {
|
|
l.tracef("revocation window exhausted, unable to send: %v, "+
|
|
"dangling_opens=%v, dangling_closes%v",
|
|
l.batchCounter, newLogClosure(func() string {
|
|
return spew.Sdump(l.openedCircuits)
|
|
}),
|
|
newLogClosure(func() string {
|
|
return spew.Sdump(l.closedCircuits)
|
|
}),
|
|
)
|
|
return nil
|
|
} else if err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := l.ackDownStreamPackets(false); err != nil {
|
|
return err
|
|
}
|
|
|
|
commitSig := &lnwire.CommitSig{
|
|
ChanID: l.ChanID(),
|
|
CommitSig: theirCommitSig,
|
|
HtlcSigs: htlcSigs,
|
|
}
|
|
l.cfg.Peer.SendMessage(false, commitSig)
|
|
|
|
// We've just initiated a state transition, attempt to stop the
|
|
// logCommitTimer. If the timer already ticked, then we'll consume the
|
|
// value, dropping
|
|
if l.logCommitTimer != nil && !l.logCommitTimer.Stop() {
|
|
select {
|
|
case <-l.logCommitTimer.C:
|
|
default:
|
|
}
|
|
}
|
|
l.logCommitTick = nil
|
|
|
|
// Finally, clear our the current batch, so we can accurately make
|
|
// further batch flushing decisions.
|
|
l.batchCounter = 0
|
|
|
|
return nil
|
|
}
|
|
|
|
// Peer returns the representation of remote peer with which we have the
|
|
// channel link opened.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) Peer() lnpeer.Peer {
|
|
return l.cfg.Peer
|
|
}
|
|
|
|
// ShortChanID returns the short channel ID for the channel link. The short
|
|
// channel ID encodes the exact location in the main chain that the original
|
|
// funding output can be found.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) ShortChanID() lnwire.ShortChannelID {
|
|
l.RLock()
|
|
defer l.RUnlock()
|
|
|
|
return l.shortChanID
|
|
}
|
|
|
|
// UpdateShortChanID updates the short channel ID for a link. This may be
|
|
// required in the event that a link is created before the short chan ID for it
|
|
// is known, or a re-org occurs, and the funding transaction changes location
|
|
// within the chain.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) UpdateShortChanID() (lnwire.ShortChannelID, error) {
|
|
chanID := l.ChanID()
|
|
|
|
// Refresh the channel state's short channel ID by loading it from disk.
|
|
// This ensures that the channel state accurately reflects the updated
|
|
// short channel ID.
|
|
err := l.channel.State().RefreshShortChanID()
|
|
if err != nil {
|
|
l.errorf("unable to refresh short_chan_id for chan_id=%v: %v",
|
|
chanID, err)
|
|
return sourceHop, err
|
|
}
|
|
|
|
sid := l.channel.ShortChanID()
|
|
|
|
l.infof("Updating to short_chan_id=%v for chan_id=%v", sid, chanID)
|
|
|
|
l.Lock()
|
|
l.shortChanID = sid
|
|
l.Unlock()
|
|
|
|
go func() {
|
|
err := l.cfg.UpdateContractSignals(&contractcourt.ContractSignals{
|
|
HtlcUpdates: l.htlcUpdates,
|
|
ShortChanID: sid,
|
|
})
|
|
if err != nil {
|
|
log.Errorf("Unable to update signals for "+
|
|
"ChannelLink(%v)", l)
|
|
}
|
|
}()
|
|
|
|
return sid, nil
|
|
}
|
|
|
|
// ChanID returns the channel ID for the channel link. The channel ID is a more
|
|
// compact representation of a channel's full outpoint.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) ChanID() lnwire.ChannelID {
|
|
return lnwire.NewChanIDFromOutPoint(l.channel.ChannelPoint())
|
|
}
|
|
|
|
// Bandwidth returns the total amount that can flow through the channel link at
|
|
// this given instance. The value returned is expressed in millisatoshi and can
|
|
// be used by callers when making forwarding decisions to determine if a link
|
|
// can accept an HTLC.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) Bandwidth() lnwire.MilliSatoshi {
|
|
channelBandwidth := l.channel.AvailableBalance()
|
|
overflowBandwidth := l.overflowQueue.TotalHtlcAmount()
|
|
|
|
// To compute the total bandwidth, we'll take the current available
|
|
// bandwidth, then subtract the overflow bandwidth as we'll eventually
|
|
// also need to evaluate those HTLC's once space on the commitment
|
|
// transaction is free.
|
|
linkBandwidth := channelBandwidth - overflowBandwidth
|
|
|
|
// If the channel reserve is greater than the total available balance
|
|
// of the link, just return 0.
|
|
reserve := lnwire.NewMSatFromSatoshis(l.channel.LocalChanReserve())
|
|
if linkBandwidth < reserve {
|
|
return 0
|
|
}
|
|
|
|
// Else the amount that is available to flow through the link at this
|
|
// point is the available balance minus the reserve amount we are
|
|
// required to keep as collateral.
|
|
return linkBandwidth - reserve
|
|
}
|
|
|
|
// AttachMailBox updates the current mailbox used by this link, and hooks up
|
|
// the mailbox's message and packet outboxes to the link's upstream and
|
|
// downstream chans, respectively.
|
|
func (l *channelLink) AttachMailBox(mailbox MailBox) {
|
|
l.Lock()
|
|
l.mailBox = mailbox
|
|
l.upstream = mailbox.MessageOutBox()
|
|
l.downstream = mailbox.PacketOutBox()
|
|
l.Unlock()
|
|
}
|
|
|
|
// UpdateForwardingPolicy updates the forwarding policy for the target
|
|
// ChannelLink. Once updated, the link will use the new forwarding policy to
|
|
// govern if it an incoming HTLC should be forwarded or not. Note that this
|
|
// processing of the new policy will ensure that uninitialized fields in the
|
|
// passed policy won't override already initialized fields in the current
|
|
// policy.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) UpdateForwardingPolicy(newPolicy ForwardingPolicy) {
|
|
l.Lock()
|
|
defer l.Unlock()
|
|
|
|
// In order to avoid overriding a valid policy with a "null" field in
|
|
// the new policy, we'll only update to the set sub policy if the new
|
|
// value isn't uninitialized.
|
|
if newPolicy.BaseFee != 0 {
|
|
l.cfg.FwrdingPolicy.BaseFee = newPolicy.BaseFee
|
|
}
|
|
if newPolicy.FeeRate != 0 {
|
|
l.cfg.FwrdingPolicy.FeeRate = newPolicy.FeeRate
|
|
}
|
|
if newPolicy.TimeLockDelta != 0 {
|
|
l.cfg.FwrdingPolicy.TimeLockDelta = newPolicy.TimeLockDelta
|
|
}
|
|
if newPolicy.MinHTLC != 0 {
|
|
l.cfg.FwrdingPolicy.MinHTLC = newPolicy.MinHTLC
|
|
}
|
|
}
|
|
|
|
// HtlcSatifiesPolicy should return a nil error if the passed HTLC details
|
|
// satisfy the current forwarding policy fo the target link. Otherwise, a
|
|
// valid protocol failure message should be returned in order to signal to the
|
|
// source of the HTLC, the policy consistency issue.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) HtlcSatifiesPolicy(payHash [32]byte,
|
|
incomingHtlcAmt, amtToForward lnwire.MilliSatoshi,
|
|
incomingTimeout, outgoingTimeout uint32,
|
|
heightNow uint32) lnwire.FailureMessage {
|
|
|
|
l.RLock()
|
|
policy := l.cfg.FwrdingPolicy
|
|
l.RUnlock()
|
|
|
|
// As our first sanity check, we'll ensure that the passed HTLC isn't
|
|
// too small for the next hop. If so, then we'll cancel the HTLC
|
|
// directly.
|
|
if amtToForward < policy.MinHTLC {
|
|
l.errorf("outgoing htlc(%x) is too small: min_htlc=%v, "+
|
|
"htlc_value=%v", payHash[:], policy.MinHTLC,
|
|
amtToForward)
|
|
|
|
// As part of the returned error, we'll send our latest routing
|
|
// policy so the sending node obtains the most up to date data.
|
|
var failure lnwire.FailureMessage
|
|
update, err := l.cfg.FetchLastChannelUpdate(l.ShortChanID())
|
|
if err != nil {
|
|
failure = &lnwire.FailTemporaryNodeFailure{}
|
|
} else {
|
|
failure = lnwire.NewAmountBelowMinimum(
|
|
amtToForward, *update,
|
|
)
|
|
}
|
|
|
|
return failure
|
|
}
|
|
|
|
// Next, using the amount of the incoming HTLC, we'll calculate the
|
|
// expected fee this incoming HTLC must carry in order to satisfy the
|
|
// constraints of the outgoing link.
|
|
expectedFee := ExpectedFee(policy, amtToForward)
|
|
|
|
// If the actual fee is less than our expected fee, then we'll reject
|
|
// this HTLC as it didn't provide a sufficient amount of fees, or the
|
|
// values have been tampered with, or the send used incorrect/dated
|
|
// information to construct the forwarding information for this hop. In
|
|
// any case, we'll cancel this HTLC.
|
|
actualFee := incomingHtlcAmt - amtToForward
|
|
if incomingHtlcAmt < amtToForward || actualFee < expectedFee {
|
|
l.errorf("outgoing htlc(%x) has insufficient fee: expected %v, "+
|
|
"got %v", payHash[:], int64(expectedFee), int64(actualFee))
|
|
|
|
// As part of the returned error, we'll send our latest routing
|
|
// policy so the sending node obtains the most up to date data.
|
|
var failure lnwire.FailureMessage
|
|
update, err := l.cfg.FetchLastChannelUpdate(l.ShortChanID())
|
|
if err != nil {
|
|
failure = &lnwire.FailTemporaryNodeFailure{}
|
|
} else {
|
|
failure = lnwire.NewFeeInsufficient(
|
|
amtToForward, *update,
|
|
)
|
|
}
|
|
|
|
return failure
|
|
}
|
|
|
|
// We want to avoid accepting an HTLC which will expire in the near
|
|
// future, so we'll reject an HTLC if its expiration time is too close
|
|
// to the current height.
|
|
timeDelta := policy.TimeLockDelta
|
|
if incomingTimeout-timeDelta <= heightNow {
|
|
l.errorf("htlc(%x) has an expiry that's too soon: "+
|
|
"outgoing_expiry=%v, best_height=%v", payHash[:],
|
|
incomingTimeout-timeDelta, heightNow)
|
|
|
|
var failure lnwire.FailureMessage
|
|
update, err := l.cfg.FetchLastChannelUpdate(
|
|
l.ShortChanID(),
|
|
)
|
|
if err != nil {
|
|
failure = lnwire.NewTemporaryChannelFailure(update)
|
|
} else {
|
|
failure = lnwire.NewExpiryTooSoon(*update)
|
|
}
|
|
|
|
return failure
|
|
}
|
|
|
|
// Finally, we'll ensure that the time-lock on the outgoing HTLC meets
|
|
// the following constraint: the incoming time-lock minus our time-lock
|
|
// delta should equal the outgoing time lock. Otherwise, whether the
|
|
// sender messed up, or an intermediate node tampered with the HTLC.
|
|
if incomingTimeout-timeDelta < outgoingTimeout {
|
|
l.errorf("Incoming htlc(%x) has incorrect time-lock value: "+
|
|
"expected at least %v block delta, got %v block delta",
|
|
payHash[:], timeDelta, incomingTimeout-outgoingTimeout)
|
|
|
|
// Grab the latest routing policy so the sending node is up to
|
|
// date with our current policy.
|
|
var failure lnwire.FailureMessage
|
|
update, err := l.cfg.FetchLastChannelUpdate(
|
|
l.ShortChanID(),
|
|
)
|
|
if err != nil {
|
|
failure = lnwire.NewTemporaryChannelFailure(update)
|
|
} else {
|
|
failure = lnwire.NewIncorrectCltvExpiry(
|
|
incomingTimeout, *update,
|
|
)
|
|
}
|
|
|
|
return failure
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Stats returns the statistics of channel link.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) Stats() (uint64, lnwire.MilliSatoshi, lnwire.MilliSatoshi) {
|
|
snapshot := l.channel.StateSnapshot()
|
|
|
|
return snapshot.ChannelCommitment.CommitHeight,
|
|
snapshot.TotalMSatSent,
|
|
snapshot.TotalMSatReceived
|
|
}
|
|
|
|
// String returns the string representation of channel link.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) String() string {
|
|
return l.channel.ChannelPoint().String()
|
|
}
|
|
|
|
// HandleSwitchPacket handles the switch packets. This packets which might be
|
|
// forwarded to us from another channel link in case the htlc update came from
|
|
// another peer or if the update was created by user
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) HandleSwitchPacket(pkt *htlcPacket) error {
|
|
l.tracef("received switch packet inkey=%v, outkey=%v",
|
|
pkt.inKey(), pkt.outKey())
|
|
|
|
l.mailBox.AddPacket(pkt)
|
|
return nil
|
|
}
|
|
|
|
// HandleChannelUpdate handles the htlc requests as settle/add/fail which sent
|
|
// to us from remote peer we have a channel with.
|
|
//
|
|
// NOTE: Part of the ChannelLink interface.
|
|
func (l *channelLink) HandleChannelUpdate(message lnwire.Message) {
|
|
l.mailBox.AddMessage(message)
|
|
}
|
|
|
|
// updateChannelFee updates the commitment fee-per-kw on this channel by
|
|
// committing to an update_fee message.
|
|
func (l *channelLink) updateChannelFee(feePerKw lnwallet.SatPerKWeight) error {
|
|
|
|
log.Infof("ChannelPoint(%v): updating commit fee to %v sat/kw", l,
|
|
feePerKw)
|
|
|
|
// We skip sending the UpdateFee message if the channel is not
|
|
// currently eligible to forward messages.
|
|
if !l.EligibleToForward() {
|
|
log.Debugf("ChannelPoint(%v): skipping fee update for "+
|
|
"inactive channel", l.ChanID())
|
|
return nil
|
|
}
|
|
|
|
// First, we'll update the local fee on our commitment.
|
|
if err := l.channel.UpdateFee(feePerKw); err != nil {
|
|
return err
|
|
}
|
|
|
|
// We'll then attempt to send a new UpdateFee message, and also lock it
|
|
// in immediately by triggering a commitment update.
|
|
msg := lnwire.NewUpdateFee(l.ChanID(), uint32(feePerKw))
|
|
if err := l.cfg.Peer.SendMessage(false, msg); err != nil {
|
|
return err
|
|
}
|
|
return l.updateCommitTx()
|
|
}
|
|
|
|
// processRemoteSettleFails accepts a batch of settle/fail payment descriptors
|
|
// after receiving a revocation from the remote party, and reprocesses them in
|
|
// the context of the provided forwarding package. Any settles or fails that
|
|
// have already been acknowledged in the forwarding package will not be sent to
|
|
// the switch.
|
|
func (l *channelLink) processRemoteSettleFails(fwdPkg *channeldb.FwdPkg,
|
|
settleFails []*lnwallet.PaymentDescriptor) {
|
|
|
|
if len(settleFails) == 0 {
|
|
return
|
|
}
|
|
|
|
log.Debugf("ChannelLink(%v): settle-fail-filter %v",
|
|
l.ShortChanID(), fwdPkg.SettleFailFilter)
|
|
|
|
var switchPackets []*htlcPacket
|
|
for i, pd := range settleFails {
|
|
// Skip any settles or fails that have already been
|
|
// acknowledged by the incoming link that originated the
|
|
// forwarded Add.
|
|
if fwdPkg.SettleFailFilter.Contains(uint16(i)) {
|
|
continue
|
|
}
|
|
|
|
// TODO(roasbeef): rework log entries to a shared
|
|
// interface.
|
|
|
|
switch pd.EntryType {
|
|
|
|
// A settle for an HTLC we previously forwarded HTLC has been
|
|
// received. So we'll forward the HTLC to the switch which will
|
|
// handle propagating the settle to the prior hop.
|
|
case lnwallet.Settle:
|
|
// If hodl.SettleIncoming is requested, we will not
|
|
// forward the SETTLE to the switch and will not signal
|
|
// a free slot on the commitment transaction.
|
|
if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.SettleIncoming) {
|
|
l.warnf(hodl.SettleIncoming.Warning())
|
|
continue
|
|
}
|
|
|
|
settlePacket := &htlcPacket{
|
|
outgoingChanID: l.ShortChanID(),
|
|
outgoingHTLCID: pd.ParentIndex,
|
|
destRef: pd.DestRef,
|
|
htlc: &lnwire.UpdateFulfillHTLC{
|
|
PaymentPreimage: pd.RPreimage,
|
|
},
|
|
}
|
|
|
|
// Add the packet to the batch to be forwarded, and
|
|
// notify the overflow queue that a spare spot has been
|
|
// freed up within the commitment state.
|
|
switchPackets = append(switchPackets, settlePacket)
|
|
l.overflowQueue.SignalFreeSlot()
|
|
|
|
// A failureCode message for a previously forwarded HTLC has
|
|
// been received. As a result a new slot will be freed up in
|
|
// our commitment state, so we'll forward this to the switch so
|
|
// the backwards undo can continue.
|
|
case lnwallet.Fail:
|
|
// If hodl.SettleIncoming is requested, we will not
|
|
// forward the FAIL to the switch and will not signal a
|
|
// free slot on the commitment transaction.
|
|
if l.cfg.DebugHTLC && l.cfg.HodlMask.Active(hodl.FailIncoming) {
|
|
l.warnf(hodl.FailIncoming.Warning())
|
|
continue
|
|
}
|
|
|
|
// Fetch the reason the HTLC was cancelled so we can
|
|
// continue to propagate it.
|
|
failPacket := &htlcPacket{
|
|
outgoingChanID: l.ShortChanID(),
|
|
outgoingHTLCID: pd.ParentIndex,
|
|
destRef: pd.DestRef,
|
|
htlc: &lnwire.UpdateFailHTLC{
|
|
Reason: lnwire.OpaqueReason(pd.FailReason),
|
|
},
|
|
}
|
|
|
|
// Add the packet to the batch to be forwarded, and
|
|
// notify the overflow queue that a spare spot has been
|
|
// freed up within the commitment state.
|
|
switchPackets = append(switchPackets, failPacket)
|
|
l.overflowQueue.SignalFreeSlot()
|
|
}
|
|
}
|
|
|
|
// Only spawn the task forward packets we have a non-zero number.
|
|
if len(switchPackets) > 0 {
|
|
go l.forwardBatch(switchPackets...)
|
|
}
|
|
}
|
|
|
|
// processRemoteAdds serially processes each of the Add payment descriptors
|
|
// which have been "locked-in" by receiving a revocation from the remote party.
|
|
// The forwarding package provided instructs how to process this batch,
|
|
// indicating whether this is the first time these Adds are being processed, or
|
|
// whether we are reprocessing as a result of a failure or restart. Adds that
|
|
// have already been acknowledged in the forwarding package will be ignored.
|
|
func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
|
|
lockedInHtlcs []*lnwallet.PaymentDescriptor) bool {
|
|
|
|
l.tracef("processing %d remote adds for height %d",
|
|
len(lockedInHtlcs), fwdPkg.Height)
|
|
|
|
decodeReqs := make([]DecodeHopIteratorRequest, 0, len(lockedInHtlcs))
|
|
for _, pd := range lockedInHtlcs {
|
|
switch pd.EntryType {
|
|
|
|
// TODO(conner): remove type switch?
|
|
case lnwallet.Add:
|
|
// Before adding the new htlc to the state machine,
|
|
// parse the onion object in order to obtain the
|
|
// routing information with DecodeHopIterator function
|
|
// which process the Sphinx packet.
|
|
onionReader := bytes.NewReader(pd.OnionBlob)
|
|
|
|
req := DecodeHopIteratorRequest{
|
|
OnionReader: onionReader,
|
|
RHash: pd.RHash[:],
|
|
IncomingCltv: pd.Timeout,
|
|
}
|
|
|
|
decodeReqs = append(decodeReqs, req)
|
|
}
|
|
}
|
|
|
|
// Atomically decode the incoming htlcs, simultaneously checking for
|
|
// replay attempts. A particular index in the returned, spare list of
|
|
// channel iterators should only be used if the failure code at the
|
|
// same index is lnwire.FailCodeNone.
|
|
decodeResps, sphinxErr := l.cfg.DecodeHopIterators(
|
|
fwdPkg.ID(), decodeReqs,
|
|
)
|
|
if sphinxErr != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to decode hop iterators: %v", sphinxErr)
|
|
return false
|
|
}
|
|
|
|
var (
|
|
needUpdate bool
|
|
switchPackets []*htlcPacket
|
|
)
|
|
|
|
for i, pd := range lockedInHtlcs {
|
|
idx := uint16(i)
|
|
|
|
if fwdPkg.State == channeldb.FwdStateProcessed &&
|
|
fwdPkg.AckFilter.Contains(idx) {
|
|
|
|
// If this index is already found in the ack filter,
|
|
// the response to this forwarding decision has already
|
|
// been committed by one of our commitment txns. ADDs
|
|
// in this state are waiting for the rest of the fwding
|
|
// package to get acked before being garbage collected.
|
|
continue
|
|
}
|
|
|
|
// An incoming HTLC add has been full-locked in. As a result we
|
|
// can now examine the forwarding details of the HTLC, and the
|
|
// HTLC itself to decide if: we should forward it, cancel it,
|
|
// or are able to settle it (and it adheres to our fee related
|
|
// constraints).
|
|
|
|
// Fetch the onion blob that was included within this processed
|
|
// payment descriptor.
|
|
var onionBlob [lnwire.OnionPacketSize]byte
|
|
copy(onionBlob[:], pd.OnionBlob)
|
|
|
|
// Before adding the new htlc to the state machine, parse the
|
|
// onion object in order to obtain the routing information with
|
|
// DecodeHopIterator function which process the Sphinx packet.
|
|
chanIterator, failureCode := decodeResps[i].Result()
|
|
if failureCode != lnwire.CodeNone {
|
|
// If we're unable to process the onion blob than we
|
|
// should send the malformed htlc error to payment
|
|
// sender.
|
|
l.sendMalformedHTLCError(pd.HtlcIndex, failureCode,
|
|
onionBlob[:], pd.SourceRef)
|
|
needUpdate = true
|
|
|
|
log.Errorf("unable to decode onion hop "+
|
|
"iterator: %v", failureCode)
|
|
continue
|
|
}
|
|
|
|
// Retrieve onion obfuscator from onion blob in order to
|
|
// produce initial obfuscation of the onion failureCode.
|
|
obfuscator, failureCode := chanIterator.ExtractErrorEncrypter(
|
|
l.cfg.ExtractErrorEncrypter,
|
|
)
|
|
if failureCode != lnwire.CodeNone {
|
|
// If we're unable to process the onion blob than we
|
|
// should send the malformed htlc error to payment
|
|
// sender.
|
|
l.sendMalformedHTLCError(pd.HtlcIndex, failureCode,
|
|
onionBlob[:], pd.SourceRef)
|
|
needUpdate = true
|
|
|
|
log.Errorf("unable to decode onion "+
|
|
"obfuscator: %v", failureCode)
|
|
continue
|
|
}
|
|
|
|
heightNow := l.cfg.Switch.BestHeight()
|
|
|
|
fwdInfo := chanIterator.ForwardingInstructions()
|
|
switch fwdInfo.NextHop {
|
|
case exitHop:
|
|
// If hodl.ExitSettle is requested, we will not validate
|
|
// the final hop's ADD, nor will we settle the
|
|
// corresponding invoice or respond with the preimage.
|
|
if l.cfg.DebugHTLC &&
|
|
l.cfg.HodlMask.Active(hodl.ExitSettle) {
|
|
l.warnf(hodl.ExitSettle.Warning())
|
|
continue
|
|
}
|
|
|
|
// First, we'll check the expiry of the HTLC itself
|
|
// against, the current block height. If the timeout is
|
|
// too soon, then we'll reject the HTLC.
|
|
if pd.Timeout-expiryGraceDelta <= heightNow {
|
|
log.Errorf("htlc(%x) has an expiry that's too "+
|
|
"soon: expiry=%v, best_height=%v",
|
|
pd.RHash[:], pd.Timeout, heightNow)
|
|
|
|
failure := lnwire.FailFinalExpiryTooSoon{}
|
|
l.sendHTLCError(
|
|
pd.HtlcIndex, &failure, obfuscator, pd.SourceRef,
|
|
)
|
|
needUpdate = true
|
|
continue
|
|
}
|
|
|
|
// We're the designated payment destination. Therefore
|
|
// we attempt to see if we have an invoice locally
|
|
// which'll allow us to settle this htlc.
|
|
invoiceHash := chainhash.Hash(pd.RHash)
|
|
invoice, minCltvDelta, err := l.cfg.Registry.LookupInvoice(
|
|
invoiceHash,
|
|
)
|
|
if err != nil {
|
|
log.Errorf("unable to query invoice registry: "+
|
|
" %v", err)
|
|
failure := lnwire.FailUnknownPaymentHash{}
|
|
l.sendHTLCError(
|
|
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
|
|
)
|
|
|
|
needUpdate = true
|
|
continue
|
|
}
|
|
|
|
// If the invoice is already settled, we choose to
|
|
// accept the payment to simplify failure recovery.
|
|
//
|
|
// NOTE: Though our recovery and forwarding logic is
|
|
// predominately batched, settling invoices happens
|
|
// iteratively. We may reject one of two payments
|
|
// for the same rhash at first, but then restart and
|
|
// reject both after seeing that the invoice has been
|
|
// settled. Without any record of which one settles
|
|
// first, it is ambiguous as to which one actually
|
|
// settled the invoice. Thus, by accepting all
|
|
// payments, we eliminate the race condition that can
|
|
// lead to this inconsistency.
|
|
//
|
|
// TODO(conner): track ownership of settlements to
|
|
// properly recover from failures? or add batch invoice
|
|
// settlement
|
|
if invoice.Terms.Settled {
|
|
log.Warnf("Accepting duplicate payment for "+
|
|
"hash=%x", pd.RHash[:])
|
|
}
|
|
|
|
// If we're not currently in debug mode, and the
|
|
// extended htlc doesn't meet the value requested, then
|
|
// we'll fail the htlc. Otherwise, we settle this htlc
|
|
// within our local state update log, then send the
|
|
// update entry to the remote party.
|
|
//
|
|
// NOTE: We make an exception when the value requested
|
|
// by the invoice is zero. This means the invoice
|
|
// allows the payee to specify the amount of satoshis
|
|
// they wish to send. So since we expect the htlc to
|
|
// have a different amount, we should not fail.
|
|
if !l.cfg.DebugHTLC && invoice.Terms.Value > 0 &&
|
|
pd.Amount < invoice.Terms.Value {
|
|
|
|
log.Errorf("rejecting htlc due to incorrect "+
|
|
"amount: expected %v, received %v",
|
|
invoice.Terms.Value, pd.Amount)
|
|
|
|
failure := lnwire.FailIncorrectPaymentAmount{}
|
|
l.sendHTLCError(
|
|
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
|
|
)
|
|
|
|
needUpdate = true
|
|
continue
|
|
}
|
|
|
|
// As we're the exit hop, we'll double check the
|
|
// hop-payload included in the HTLC to ensure that it
|
|
// was crafted correctly by the sender and matches the
|
|
// HTLC we were extended.
|
|
//
|
|
// NOTE: We make an exception when the value requested
|
|
// by the invoice is zero. This means the invoice
|
|
// allows the payee to specify the amount of satoshis
|
|
// they wish to send. So since we expect the htlc to
|
|
// have a different amount, we should not fail.
|
|
if !l.cfg.DebugHTLC && invoice.Terms.Value > 0 &&
|
|
fwdInfo.AmountToForward < invoice.Terms.Value {
|
|
|
|
log.Errorf("Onion payload of incoming htlc(%x) "+
|
|
"has incorrect value: expected %v, "+
|
|
"got %v", pd.RHash, invoice.Terms.Value,
|
|
fwdInfo.AmountToForward)
|
|
|
|
failure := lnwire.FailIncorrectPaymentAmount{}
|
|
l.sendHTLCError(
|
|
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
|
|
)
|
|
|
|
needUpdate = true
|
|
continue
|
|
}
|
|
|
|
// We'll also ensure that our time-lock value has been
|
|
// computed correctly.
|
|
expectedHeight := heightNow + minCltvDelta
|
|
switch {
|
|
|
|
case !l.cfg.DebugHTLC && fwdInfo.OutgoingCTLV < expectedHeight:
|
|
log.Errorf("Onion payload of incoming "+
|
|
"htlc(%x) has incorrect time-lock: "+
|
|
"expected %v, got %v",
|
|
pd.RHash[:], expectedHeight,
|
|
fwdInfo.OutgoingCTLV)
|
|
|
|
failure := lnwire.NewFinalIncorrectCltvExpiry(
|
|
fwdInfo.OutgoingCTLV,
|
|
)
|
|
l.sendHTLCError(
|
|
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
|
|
)
|
|
|
|
needUpdate = true
|
|
continue
|
|
|
|
case !l.cfg.DebugHTLC && pd.Timeout != fwdInfo.OutgoingCTLV:
|
|
log.Errorf("HTLC(%x) has incorrect "+
|
|
"time-lock: expected %v, got %v",
|
|
pd.RHash[:], pd.Timeout,
|
|
fwdInfo.OutgoingCTLV)
|
|
|
|
failure := lnwire.NewFinalIncorrectCltvExpiry(
|
|
fwdInfo.OutgoingCTLV,
|
|
)
|
|
l.sendHTLCError(
|
|
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
|
|
)
|
|
|
|
needUpdate = true
|
|
continue
|
|
}
|
|
|
|
preimage := invoice.Terms.PaymentPreimage
|
|
err = l.channel.SettleHTLC(
|
|
preimage, pd.HtlcIndex, pd.SourceRef, nil, nil,
|
|
)
|
|
if err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to settle htlc: %v", err)
|
|
return false
|
|
}
|
|
|
|
// Notify the invoiceRegistry of the invoices we just
|
|
// settled (with the amount accepted at settle time)
|
|
// with this latest commitment update.
|
|
err = l.cfg.Registry.SettleInvoice(
|
|
invoiceHash, pd.Amount,
|
|
)
|
|
if err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to settle invoice: %v", err)
|
|
return false
|
|
}
|
|
|
|
l.infof("settling %x as exit hop", pd.RHash)
|
|
|
|
// If the link is in hodl.BogusSettle mode, replace the
|
|
// preimage with a fake one before sending it to the
|
|
// peer.
|
|
if l.cfg.DebugHTLC &&
|
|
l.cfg.HodlMask.Active(hodl.BogusSettle) {
|
|
l.warnf(hodl.BogusSettle.Warning())
|
|
preimage = [32]byte{}
|
|
copy(preimage[:], bytes.Repeat([]byte{2}, 32))
|
|
}
|
|
|
|
// HTLC was successfully settled locally send
|
|
// notification about it remote peer.
|
|
l.cfg.Peer.SendMessage(false, &lnwire.UpdateFulfillHTLC{
|
|
ChanID: l.ChanID(),
|
|
ID: pd.HtlcIndex,
|
|
PaymentPreimage: preimage,
|
|
})
|
|
needUpdate = true
|
|
|
|
// There are additional channels left within this route. So
|
|
// we'll simply do some forwarding package book-keeping.
|
|
default:
|
|
// If hodl.AddIncoming is requested, we will not
|
|
// validate the forwarded ADD, nor will we send the
|
|
// packet to the htlc switch.
|
|
if l.cfg.DebugHTLC &&
|
|
l.cfg.HodlMask.Active(hodl.AddIncoming) {
|
|
l.warnf(hodl.AddIncoming.Warning())
|
|
continue
|
|
}
|
|
|
|
switch fwdPkg.State {
|
|
case channeldb.FwdStateProcessed:
|
|
// This add was not forwarded on the previous
|
|
// processing phase, run it through our
|
|
// validation pipeline to reproduce an error.
|
|
// This may trigger a different error due to
|
|
// expiring timelocks, but we expect that an
|
|
// error will be reproduced.
|
|
if !fwdPkg.FwdFilter.Contains(idx) {
|
|
break
|
|
}
|
|
|
|
// Otherwise, it was already processed, we can
|
|
// can collect it and continue.
|
|
addMsg := &lnwire.UpdateAddHTLC{
|
|
Expiry: fwdInfo.OutgoingCTLV,
|
|
Amount: fwdInfo.AmountToForward,
|
|
PaymentHash: pd.RHash,
|
|
}
|
|
|
|
// Finally, we'll encode the onion packet for
|
|
// the _next_ hop using the hop iterator
|
|
// decoded for the current hop.
|
|
buf := bytes.NewBuffer(addMsg.OnionBlob[0:0])
|
|
|
|
// We know this cannot fail, as this ADD
|
|
// was marked forwarded in a previous
|
|
// round of processing.
|
|
chanIterator.EncodeNextHop(buf)
|
|
|
|
updatePacket := &htlcPacket{
|
|
incomingChanID: l.ShortChanID(),
|
|
incomingHTLCID: pd.HtlcIndex,
|
|
outgoingChanID: fwdInfo.NextHop,
|
|
sourceRef: pd.SourceRef,
|
|
incomingAmount: pd.Amount,
|
|
amount: addMsg.Amount,
|
|
htlc: addMsg,
|
|
obfuscator: obfuscator,
|
|
incomingTimeout: pd.Timeout,
|
|
outgoingTimeout: fwdInfo.OutgoingCTLV,
|
|
}
|
|
switchPackets = append(
|
|
switchPackets, updatePacket,
|
|
)
|
|
|
|
continue
|
|
}
|
|
|
|
// TODO(roasbeef): ensure don't accept outrageous
|
|
// timeout for htlc
|
|
|
|
// With all our forwarding constraints met, we'll
|
|
// create the outgoing HTLC using the parameters as
|
|
// specified in the forwarding info.
|
|
addMsg := &lnwire.UpdateAddHTLC{
|
|
Expiry: fwdInfo.OutgoingCTLV,
|
|
Amount: fwdInfo.AmountToForward,
|
|
PaymentHash: pd.RHash,
|
|
}
|
|
|
|
// Finally, we'll encode the onion packet for the
|
|
// _next_ hop using the hop iterator decoded for the
|
|
// current hop.
|
|
buf := bytes.NewBuffer(addMsg.OnionBlob[0:0])
|
|
err := chanIterator.EncodeNextHop(buf)
|
|
if err != nil {
|
|
log.Errorf("unable to encode the "+
|
|
"remaining route %v", err)
|
|
|
|
var failure lnwire.FailureMessage
|
|
update, err := l.cfg.FetchLastChannelUpdate(
|
|
l.ShortChanID(),
|
|
)
|
|
if err != nil {
|
|
failure = &lnwire.FailTemporaryNodeFailure{}
|
|
} else {
|
|
failure = lnwire.NewTemporaryChannelFailure(
|
|
update,
|
|
)
|
|
}
|
|
|
|
l.sendHTLCError(
|
|
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
|
|
)
|
|
needUpdate = true
|
|
continue
|
|
}
|
|
|
|
// Now that this add has been reprocessed, only append
|
|
// it to our list of packets to forward to the switch
|
|
// this is the first time processing the add. If the
|
|
// fwd pkg has already been processed, then we entered
|
|
// the above section to recreate a previous error. If
|
|
// the packet had previously been forwarded, it would
|
|
// have been added to switchPackets at the top of this
|
|
// section.
|
|
if fwdPkg.State == channeldb.FwdStateLockedIn {
|
|
updatePacket := &htlcPacket{
|
|
incomingChanID: l.ShortChanID(),
|
|
incomingHTLCID: pd.HtlcIndex,
|
|
outgoingChanID: fwdInfo.NextHop,
|
|
sourceRef: pd.SourceRef,
|
|
incomingAmount: pd.Amount,
|
|
amount: addMsg.Amount,
|
|
htlc: addMsg,
|
|
obfuscator: obfuscator,
|
|
incomingTimeout: pd.Timeout,
|
|
outgoingTimeout: fwdInfo.OutgoingCTLV,
|
|
}
|
|
|
|
fwdPkg.FwdFilter.Set(idx)
|
|
switchPackets = append(switchPackets,
|
|
updatePacket)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Commit the htlcs we are intending to forward if this package has not
|
|
// been fully processed.
|
|
if fwdPkg.State == channeldb.FwdStateLockedIn {
|
|
err := l.channel.SetFwdFilter(fwdPkg.Height, fwdPkg.FwdFilter)
|
|
if err != nil {
|
|
l.fail(LinkFailureError{code: ErrInternalError},
|
|
"unable to set fwd filter: %v", err)
|
|
return false
|
|
}
|
|
}
|
|
|
|
if len(switchPackets) == 0 {
|
|
return needUpdate
|
|
}
|
|
|
|
l.debugf("forwarding %d packets to switch", len(switchPackets))
|
|
|
|
// NOTE: This call is made synchronous so that we ensure all circuits
|
|
// are committed in the exact order that they are processed in the link.
|
|
// Failing to do this could cause reorderings/gaps in the range of
|
|
// opened circuits, which violates assumptions made by the circuit
|
|
// trimming.
|
|
l.forwardBatch(switchPackets...)
|
|
|
|
return needUpdate
|
|
}
|
|
|
|
// forwardBatch forwards the given htlcPackets to the switch, and waits on the
|
|
// err chan for the individual responses. This method is intended to be spawned
|
|
// as a goroutine so the responses can be handled in the background.
|
|
func (l *channelLink) forwardBatch(packets ...*htlcPacket) {
|
|
// Don't forward packets for which we already have a response in our
|
|
// mailbox. This could happen if a packet fails and is buffered in the
|
|
// mailbox, and the incoming link flaps.
|
|
var filteredPkts = make([]*htlcPacket, 0, len(packets))
|
|
for _, pkt := range packets {
|
|
if l.mailBox.HasPacket(pkt.inKey()) {
|
|
continue
|
|
}
|
|
|
|
filteredPkts = append(filteredPkts, pkt)
|
|
}
|
|
|
|
errChan := l.cfg.ForwardPackets(filteredPkts...)
|
|
go l.handleBatchFwdErrs(errChan)
|
|
}
|
|
|
|
// handleBatchFwdErrs waits on the given errChan until it is closed, logging
|
|
// the errors returned from any unsuccessful forwarding attempts.
|
|
func (l *channelLink) handleBatchFwdErrs(errChan chan error) {
|
|
for {
|
|
err, ok := <-errChan
|
|
if !ok {
|
|
// Err chan has been drained or switch is shutting
|
|
// down. Either way, return.
|
|
return
|
|
}
|
|
|
|
if err == nil {
|
|
continue
|
|
}
|
|
|
|
l.errorf("unhandled error while forwarding htlc packet over "+
|
|
"htlcswitch: %v", err)
|
|
}
|
|
}
|
|
|
|
// sendHTLCError functions cancels HTLC and send cancel message back to the
|
|
// peer from which HTLC was received.
|
|
func (l *channelLink) sendHTLCError(htlcIndex uint64, failure lnwire.FailureMessage,
|
|
e ErrorEncrypter, sourceRef *channeldb.AddRef) {
|
|
|
|
reason, err := e.EncryptFirstHop(failure)
|
|
if err != nil {
|
|
log.Errorf("unable to obfuscate error: %v", err)
|
|
return
|
|
}
|
|
|
|
err = l.channel.FailHTLC(htlcIndex, reason, sourceRef, nil, nil)
|
|
if err != nil {
|
|
log.Errorf("unable cancel htlc: %v", err)
|
|
return
|
|
}
|
|
|
|
l.cfg.Peer.SendMessage(false, &lnwire.UpdateFailHTLC{
|
|
ChanID: l.ChanID(),
|
|
ID: htlcIndex,
|
|
Reason: reason,
|
|
})
|
|
}
|
|
|
|
// sendMalformedHTLCError helper function which sends the malformed HTLC update
|
|
// to the payment sender.
|
|
func (l *channelLink) sendMalformedHTLCError(htlcIndex uint64,
|
|
code lnwire.FailCode, onionBlob []byte, sourceRef *channeldb.AddRef) {
|
|
|
|
shaOnionBlob := sha256.Sum256(onionBlob)
|
|
err := l.channel.MalformedFailHTLC(htlcIndex, code, shaOnionBlob, sourceRef)
|
|
if err != nil {
|
|
log.Errorf("unable cancel htlc: %v", err)
|
|
return
|
|
}
|
|
|
|
l.cfg.Peer.SendMessage(false, &lnwire.UpdateFailMalformedHTLC{
|
|
ChanID: l.ChanID(),
|
|
ID: htlcIndex,
|
|
ShaOnionBlob: shaOnionBlob,
|
|
FailureCode: code,
|
|
})
|
|
}
|
|
|
|
// fail is a function which is used to encapsulate the action necessary for
|
|
// properly failing the link. It takes a LinkFailureError, which will be passed
|
|
// to the OnChannelFailure closure, in order for it to determine if we should
|
|
// force close the channel, and if we should send an error message to the
|
|
// remote peer.
|
|
func (l *channelLink) fail(linkErr LinkFailureError,
|
|
format string, a ...interface{}) {
|
|
reason := errors.Errorf(format, a...)
|
|
|
|
// Return if we have already notified about a failure.
|
|
if l.failed {
|
|
l.warnf("Ignoring link failure (%v), as link already failed",
|
|
reason)
|
|
return
|
|
}
|
|
|
|
l.errorf("Failing link: %s", reason)
|
|
|
|
// Set failed, such that we won't process any more updates, and notify
|
|
// the peer about the failure.
|
|
l.failed = true
|
|
l.cfg.OnChannelFailure(l.ChanID(), l.ShortChanID(), linkErr)
|
|
}
|
|
|
|
// infof prefixes the channel's identifier before printing to info log.
|
|
func (l *channelLink) infof(format string, a ...interface{}) {
|
|
msg := fmt.Sprintf(format, a...)
|
|
log.Infof("ChannelLink(%s) %s", l.ShortChanID(), msg)
|
|
}
|
|
|
|
// debugf prefixes the channel's identifier before printing to debug log.
|
|
func (l *channelLink) debugf(format string, a ...interface{}) {
|
|
msg := fmt.Sprintf(format, a...)
|
|
log.Debugf("ChannelLink(%s) %s", l.ShortChanID(), msg)
|
|
}
|
|
|
|
// warnf prefixes the channel's identifier before printing to warn log.
|
|
func (l *channelLink) warnf(format string, a ...interface{}) {
|
|
msg := fmt.Sprintf(format, a...)
|
|
log.Warnf("ChannelLink(%s) %s", l.ShortChanID(), msg)
|
|
}
|
|
|
|
// errorf prefixes the channel's identifier before printing to error log.
|
|
func (l *channelLink) errorf(format string, a ...interface{}) {
|
|
msg := fmt.Sprintf(format, a...)
|
|
log.Errorf("ChannelLink(%s) %s", l.ShortChanID(), msg)
|
|
}
|
|
|
|
// tracef prefixes the channel's identifier before printing to trace log.
|
|
func (l *channelLink) tracef(format string, a ...interface{}) {
|
|
msg := fmt.Sprintf(format, a...)
|
|
log.Tracef("ChannelLink(%s) %s", l.ShortChanID(), msg)
|
|
}
|
|
|
|
// isASCII is a helper method that checks whether all bytes in `data` would be
|
|
// printable ASCII characters if interpreted as a string.
|
|
func isASCII(data []byte) bool {
|
|
isASCII := true
|
|
for _, c := range data {
|
|
if c < 32 || c > 126 {
|
|
isASCII = false
|
|
break
|
|
}
|
|
}
|
|
return isASCII
|
|
}
|