Merge pull request #2887 from joostjager/asym-broadcast-delta
config: lower outgoing htlc broadcast delta
This commit is contained in:
commit
649991c46f
47
config.go
47
config.go
@ -68,11 +68,50 @@ const (
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defaultTorV2PrivateKeyFilename = "v2_onion_private_key"
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defaultTorV3PrivateKeyFilename = "v3_onion_private_key"
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defaultIncomingBroadcastDelta = 20
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defaultFinalCltvRejectDelta = 2
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// defaultIncomingBroadcastDelta defines the number of blocks before the
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// expiry of an incoming htlc at which we force close the channel. We
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// only go to chain if we also have the preimage to actually pull in the
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// htlc. BOLT #2 suggests 7 blocks. We use a few more for extra safety.
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// Within this window we need to get our sweep or 2nd level success tx
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// confirmed, because after that the remote party is also able to claim
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// the htlc using the timeout path.
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defaultIncomingBroadcastDelta = 10
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defaultOutgoingBroadcastDelta = 10
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defaultOutgoingCltvRejectDelta = 0
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// defaultFinalCltvRejectDelta defines the number of blocks before the
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// expiry of an incoming exit hop htlc at which we cancel it back
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// immediately. It is an extra safety measure over the final cltv
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// requirement as it is defined in the invoice. It ensures that we
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// cancel back htlcs that, when held on to, may cause us to force close
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// the channel because we enter the incoming broadcast window. Bolt #11
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// suggests 9 blocks here. We use a few more for additional safety.
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//
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// There is still a small gap that remains between receiving the
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// RevokeAndAck and canceling back. If a new block arrives within that
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// window, we may still force close the channel. There is currently no
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// way to reject an UpdateAddHtlc of which we already know that it will
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// push us in the broadcast window.
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defaultFinalCltvRejectDelta = defaultIncomingBroadcastDelta + 3
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// defaultOutgoingBroadcastDelta defines the number of blocks before the
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// expiry of an outgoing htlc at which we force close the channel. We
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// are not in a hurry to force close, because there is nothing to claim
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// for us. We do need to time the htlc out, because there may be an
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// incoming htlc that will time out too (albeit later). Bolt #2 suggests
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// a value of -1 here, but we allow one block less to prevent potential
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// confusion around the negative value. It means we force close the
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// channel at exactly the htlc expiry height.
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defaultOutgoingBroadcastDelta = 0
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// defaultOutgoingCltvRejectDelta defines the number of blocks before
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// the expiry of an outgoing htlc at which we don't want to offer it to
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// the next peer anymore. If that happens, we cancel back the incoming
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// htlc. This is to prevent the situation where we have an outstanding
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// htlc that brings or will soon bring us inside the outgoing broadcast
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// window and trigger us to force close the channel. Bolt #2 suggests a
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// value of 0. We pad it a bit, to prevent a slow round trip to the next
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// peer and a block arriving during that round trip to trigger force
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// closure.
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defaultOutgoingCltvRejectDelta = defaultOutgoingBroadcastDelta + 3
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// minTimeLockDelta is the minimum timelock we require for incoming
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// HTLCs on our channels.
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@ -107,6 +107,14 @@ type ChannelLink interface {
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incomingTimeout, outgoingTimeout uint32,
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heightNow uint32) lnwire.FailureMessage
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// HtlcSatifiesPolicyLocal should return a nil error if the passed HTLC
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// details satisfy the current channel policy. Otherwise, a valid
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// protocol failure message should be returned in order to signal the
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// violation. This call is intended to be used for locally initiated
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// payments for which there is no corresponding incoming htlc.
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HtlcSatifiesPolicyLocal(payHash [32]byte, amt lnwire.MilliSatoshi,
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timeout uint32, heightNow uint32) lnwire.FailureMessage
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// Bandwidth returns the amount of milli-satoshis which current link
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// might pass through channel link. The value returned from this method
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// represents the up to date available flow through the channel. This
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@ -2093,46 +2093,12 @@ func (l *channelLink) HtlcSatifiesPolicy(payHash [32]byte,
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policy := l.cfg.FwrdingPolicy
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l.RUnlock()
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// As our first sanity check, we'll ensure that the passed HTLC isn't
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// too small for the next hop. If so, then we'll cancel the HTLC
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// directly.
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if amtToForward < policy.MinHTLC {
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l.errorf("outgoing htlc(%x) is too small: min_htlc=%v, "+
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"htlc_value=%v", payHash[:], policy.MinHTLC,
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amtToForward)
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// As part of the returned error, we'll send our latest routing
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// policy so the sending node obtains the most up to date data.
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var failure lnwire.FailureMessage
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update, err := l.cfg.FetchLastChannelUpdate(l.ShortChanID())
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if err != nil {
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failure = &lnwire.FailTemporaryNodeFailure{}
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} else {
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failure = lnwire.NewAmountBelowMinimum(
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amtToForward, *update,
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// First check whether the outgoing htlc satisfies the channel policy.
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err := l.htlcSatifiesPolicyOutgoing(
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policy, payHash, amtToForward, outgoingTimeout, heightNow,
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)
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}
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return failure
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}
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// Next, ensure that the passed HTLC isn't too large. If so, we'll cancel
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// the HTLC directly.
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if policy.MaxHTLC != 0 && amtToForward > policy.MaxHTLC {
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l.errorf("outgoing htlc(%x) is too large: max_htlc=%v, "+
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"htlc_value=%v", payHash[:], policy.MaxHTLC, amtToForward)
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// As part of the returned error, we'll send our latest routing policy
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// so the sending node obtains the most up-to-date data.
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var failure lnwire.FailureMessage
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update, err := l.cfg.FetchLastChannelUpdate(l.ShortChanID())
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if err != nil {
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failure = &lnwire.FailTemporaryNodeFailure{}
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} else {
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failure = lnwire.NewTemporaryChannelFailure(update)
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}
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return failure
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return err
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}
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// Next, using the amount of the incoming HTLC, we'll calculate the
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@ -2165,36 +2131,6 @@ func (l *channelLink) HtlcSatifiesPolicy(payHash [32]byte,
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return failure
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}
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// We want to avoid offering an HTLC which will expire in the near
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// future, so we'll reject an HTLC if the outgoing expiration time is
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// too close to the current height.
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if outgoingTimeout <= heightNow+l.cfg.OutgoingCltvRejectDelta {
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l.errorf("htlc(%x) has an expiry that's too soon: "+
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"outgoing_expiry=%v, best_height=%v", payHash[:],
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outgoingTimeout, heightNow)
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var failure lnwire.FailureMessage
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update, err := l.cfg.FetchLastChannelUpdate(
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l.ShortChanID(),
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)
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if err != nil {
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failure = lnwire.NewTemporaryChannelFailure(update)
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} else {
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failure = lnwire.NewExpiryTooSoon(*update)
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}
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return failure
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}
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// Check absolute max delta.
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if outgoingTimeout > maxCltvExpiry+heightNow {
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l.errorf("outgoing htlc(%x) has a time lock too far in the "+
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"future: got %v, but maximum is %v", payHash[:],
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outgoingTimeout-heightNow, maxCltvExpiry)
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return &lnwire.FailExpiryTooFar{}
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}
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// Finally, we'll ensure that the time-lock on the outgoing HTLC meets
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// the following constraint: the incoming time-lock minus our time-lock
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// delta should equal the outgoing time lock. Otherwise, whether the
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@ -2225,6 +2161,105 @@ func (l *channelLink) HtlcSatifiesPolicy(payHash [32]byte,
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return nil
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}
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// HtlcSatifiesPolicyLocal should return a nil error if the passed HTLC details
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// satisfy the current channel policy. Otherwise, a valid protocol failure
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// message should be returned in order to signal the violation. This call is
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// intended to be used for locally initiated payments for which there is no
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// corresponding incoming htlc.
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func (l *channelLink) HtlcSatifiesPolicyLocal(payHash [32]byte,
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amt lnwire.MilliSatoshi, timeout uint32,
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heightNow uint32) lnwire.FailureMessage {
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l.RLock()
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policy := l.cfg.FwrdingPolicy
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l.RUnlock()
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return l.htlcSatifiesPolicyOutgoing(
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policy, payHash, amt, timeout, heightNow,
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)
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}
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// htlcSatifiesPolicyOutgoing checks whether the given htlc parameters satisfy
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// the channel's amount and time lock constraints.
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func (l *channelLink) htlcSatifiesPolicyOutgoing(policy ForwardingPolicy,
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payHash [32]byte, amt lnwire.MilliSatoshi, timeout uint32,
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heightNow uint32) lnwire.FailureMessage {
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// As our first sanity check, we'll ensure that the passed HTLC isn't
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// too small for the next hop. If so, then we'll cancel the HTLC
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// directly.
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if amt < policy.MinHTLC {
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l.errorf("outgoing htlc(%x) is too small: min_htlc=%v, "+
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"htlc_value=%v", payHash[:], policy.MinHTLC,
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amt)
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// As part of the returned error, we'll send our latest routing
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// policy so the sending node obtains the most up to date data.
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var failure lnwire.FailureMessage
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update, err := l.cfg.FetchLastChannelUpdate(l.ShortChanID())
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if err != nil {
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failure = &lnwire.FailTemporaryNodeFailure{}
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} else {
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failure = lnwire.NewAmountBelowMinimum(
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amt, *update,
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)
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}
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return failure
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}
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// Next, ensure that the passed HTLC isn't too large. If so, we'll cancel
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// the HTLC directly.
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if policy.MaxHTLC != 0 && amt > policy.MaxHTLC {
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l.errorf("outgoing htlc(%x) is too large: max_htlc=%v, "+
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"htlc_value=%v", payHash[:], policy.MaxHTLC, amt)
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// As part of the returned error, we'll send our latest routing policy
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// so the sending node obtains the most up-to-date data.
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var failure lnwire.FailureMessage
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update, err := l.cfg.FetchLastChannelUpdate(l.ShortChanID())
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if err != nil {
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failure = &lnwire.FailTemporaryNodeFailure{}
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} else {
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failure = lnwire.NewTemporaryChannelFailure(update)
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}
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return failure
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}
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// We want to avoid offering an HTLC which will expire in the near
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// future, so we'll reject an HTLC if the outgoing expiration time is
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// too close to the current height.
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if timeout <= heightNow+l.cfg.OutgoingCltvRejectDelta {
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l.errorf("htlc(%x) has an expiry that's too soon: "+
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"outgoing_expiry=%v, best_height=%v", payHash[:],
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timeout, heightNow)
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var failure lnwire.FailureMessage
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update, err := l.cfg.FetchLastChannelUpdate(
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l.ShortChanID(),
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)
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if err != nil {
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failure = lnwire.NewTemporaryChannelFailure(update)
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} else {
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failure = lnwire.NewExpiryTooSoon(*update)
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}
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return failure
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}
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// Check absolute max delta.
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if timeout > maxCltvExpiry+heightNow {
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l.errorf("outgoing htlc(%x) has a time lock too far in the "+
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"future: got %v, but maximum is %v", payHash[:],
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timeout-heightNow, maxCltvExpiry)
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return &lnwire.FailExpiryTooFar{}
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}
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return nil
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}
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// Stats returns the statistics of channel link.
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//
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// NOTE: Part of the ChannelLink interface.
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@ -1365,13 +1365,12 @@ func TestChannelLinkExpiryTooSoonExitNode(t *testing.T) {
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amount := lnwire.NewMSatFromSatoshis(btcutil.SatoshiPerBitcoin)
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// We'll craft an HTLC packet, but set the final hop CLTV to 3 blocks
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// after the current true height. This is less or equal to the expiry
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// grace delta of 3, so we expect the incoming htlc to be failed by the
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// We'll craft an HTLC packet, but set the final hop CLTV to 5 blocks
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// after the current true height. This is less than the test invoice
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// cltv delta of 6, so we expect the incoming htlc to be failed by the
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// exit hop.
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lastHopDelta := n.firstBobChannelLink.cfg.FwrdingPolicy.TimeLockDelta
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htlcAmt, totalTimelock, hops := generateHops(amount,
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startingHeight+3-lastHopDelta, n.firstBobChannelLink)
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startingHeight-1, n.firstBobChannelLink)
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// Now we'll send out the payment from Alice to Bob.
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firstHop := n.firstBobChannelLink.ShortChanID()
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@ -612,6 +612,8 @@ type mockChannelLink struct {
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eligible bool
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htlcID uint64
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htlcSatifiesPolicyLocalResult lnwire.FailureMessage
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}
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// completeCircuit is a helper method for adding the finalized payment circuit
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@ -675,6 +677,13 @@ func (f *mockChannelLink) HtlcSatifiesPolicy([32]byte, lnwire.MilliSatoshi,
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return nil
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}
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func (f *mockChannelLink) HtlcSatifiesPolicyLocal(payHash [32]byte,
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amt lnwire.MilliSatoshi, timeout uint32,
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heightNow uint32) lnwire.FailureMessage {
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return f.htlcSatifiesPolicyLocalResult
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}
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func (f *mockChannelLink) Stats() (uint64, lnwire.MilliSatoshi, lnwire.MilliSatoshi) {
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return 0, 0, 0
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}
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@ -728,7 +737,7 @@ func newDB() (*channeldb.DB, func(), error) {
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return cdb, cleanUp, nil
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}
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const testInvoiceCltvExpiry = 4
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const testInvoiceCltvExpiry = 6
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type mockInvoiceRegistry struct {
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settleChan chan lntypes.Hash
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@ -799,6 +799,23 @@ func (s *Switch) handleLocalDispatch(pkt *htlcPacket) error {
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}
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}
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// Ensure that the htlc satisfies the outgoing channel policy.
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currentHeight := atomic.LoadUint32(&s.bestHeight)
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htlcErr := link.HtlcSatifiesPolicyLocal(
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htlc.PaymentHash,
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htlc.Amount,
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htlc.Expiry, currentHeight,
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)
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if htlcErr != nil {
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log.Errorf("Link %v policy for local forward not "+
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"satisfied", pkt.outgoingChanID)
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return &ForwardingError{
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ErrorSource: s.cfg.SelfKey,
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FailureMessage: htlcErr,
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}
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}
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if link.Bandwidth() < htlc.Amount {
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err := fmt.Errorf("Link %v has insufficient capacity: "+
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"need %v, has %v", pkt.outgoingChanID,
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@ -1363,6 +1363,21 @@ func TestSkipIneligibleLinksMultiHopForward(t *testing.T) {
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func TestSkipIneligibleLinksLocalForward(t *testing.T) {
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t.Parallel()
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testSkipLinkLocalForward(t, false, nil)
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}
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// TestSkipPolicyUnsatisfiedLinkLocalForward ensures that the switch will not
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// attempt to send locally initiated HTLCs that would violate the channel policy
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// down a link.
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func TestSkipPolicyUnsatisfiedLinkLocalForward(t *testing.T) {
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t.Parallel()
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testSkipLinkLocalForward(t, true, lnwire.NewTemporaryChannelFailure(nil))
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}
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func testSkipLinkLocalForward(t *testing.T, eligible bool,
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policyResult lnwire.FailureMessage) {
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// We'll create a single link for this test, marking it as being unable
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// to forward form the get go.
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alicePeer, err := newMockServer(t, "alice", testStartingHeight, nil, 6)
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@ -1382,8 +1397,9 @@ func TestSkipIneligibleLinksLocalForward(t *testing.T) {
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chanID1, _, aliceChanID, _ := genIDs()
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aliceChannelLink := newMockChannelLink(
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s, chanID1, aliceChanID, alicePeer, false,
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s, chanID1, aliceChanID, alicePeer, eligible,
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)
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aliceChannelLink.htlcSatifiesPolicyLocalResult = policyResult
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if err := s.AddLink(aliceChannelLink); err != nil {
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t.Fatalf("unable to add alice link: %v", err)
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}
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@ -1052,7 +1052,7 @@ func (h *hopNetwork) createChannelLink(server, peer *mockServer,
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MinFeeUpdateTimeout: minFeeUpdateTimeout,
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MaxFeeUpdateTimeout: maxFeeUpdateTimeout,
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OnChannelFailure: func(lnwire.ChannelID, lnwire.ShortChannelID, LinkFailureError) {},
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FinalCltvRejectDelta: 3,
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FinalCltvRejectDelta: 5,
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OutgoingCltvRejectDelta: 3,
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},
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channel,
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|
17
lnd_test.go
17
lnd_test.go
@ -9466,7 +9466,8 @@ func testMultiHopHtlcLocalTimeout(net *lntest.NetworkHarness, t *harnessTest) {
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// We'll now mine enough blocks to trigger Bob's broadcast of his
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// commitment transaction due to the fact that the HTLC is about to
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// timeout.
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// timeout. With the default outgoing broadcast delta of zero, this will
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// be the same height as the htlc expiry height.
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numBlocks := uint32(finalCltvDelta - defaultOutgoingBroadcastDelta)
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if _, err := net.Miner.Node.Generate(numBlocks); err != nil {
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t.Fatalf("unable to generate blocks: %v", err)
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@ -9503,8 +9504,9 @@ func testMultiHopHtlcLocalTimeout(net *lntest.NetworkHarness, t *harnessTest) {
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t.Fatalf("htlc mismatch: %v", predErr)
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}
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// We'll mine defaultCSV blocks in order to generate the sweep transaction
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// of Bob's funding output.
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// We'll mine defaultCSV blocks in order to generate the sweep
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// transaction of Bob's funding output. This will also bring us to the
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// maturity height of the htlc tx output.
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if _, err := net.Miner.Node.Generate(defaultCSV); err != nil {
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t.Fatalf("unable to generate blocks: %v", err)
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}
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@ -9514,15 +9516,6 @@ func testMultiHopHtlcLocalTimeout(net *lntest.NetworkHarness, t *harnessTest) {
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t.Fatalf("unable to find bob's funding output sweep tx: %v", err)
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}
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// We'll now mine the remaining blocks to cause the HTLC itself to
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// timeout.
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_, err = net.Miner.Node.Generate(
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defaultOutgoingBroadcastDelta - defaultCSV,
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)
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if err != nil {
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t.Fatalf("unable to generate blocks: %v", err)
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}
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// The second layer HTLC timeout transaction should now have been
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// broadcast on-chain.
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secondLayerHash, err := waitForTxInMempool(net.Miner.Node, minerMempoolTimeout)
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|
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Block a user