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Merge pull request #1447 from Roasbeef/forwarding-timelock-fix
routing+htlcswitch: finalize switch of CLTV delta directionality in path finding and link forwarding
This commit is contained in:
Olaoluwa Osuntokun
GitHub
@@ -1747,7 +1747,9 @@ func (l *channelLink) UpdateForwardingPolicy(newPolicy ForwardingPolicy) {
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//
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// NOTE: Part of the ChannelLink interface.
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func (l *channelLink) HtlcSatifiesPolicy(payHash [32]byte,
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incomingHtlcAmt, amtToForward lnwire.MilliSatoshi) lnwire.FailureMessage {
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incomingHtlcAmt, amtToForward lnwire.MilliSatoshi,
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incomingTimeout, outgoingTimeout 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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@@ -1788,10 +1790,8 @@ func (l *channelLink) HtlcSatifiesPolicy(payHash [32]byte,
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// any case, we'll cancel this HTLC.
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actualFee := incomingHtlcAmt - amtToForward
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if incomingHtlcAmt < amtToForward || actualFee < expectedFee {
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l.errorf("outgoing htlc(%x) has insufficient "+
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"fee: expected %v, got %v", payHash[:],
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int64(expectedFee),
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int64(actualFee))
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l.errorf("outgoing htlc(%x) has insufficient fee: expected %v, "+
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"got %v", payHash[:], int64(expectedFee), int64(actualFee))
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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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@@ -1808,6 +1808,54 @@ 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 accepting an HTLC which will expire in the near
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// future, so we'll reject an HTLC if its expiration time is too close
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// to the current height.
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timeDelta := policy.TimeLockDelta
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if incomingTimeout-timeDelta <= heightNow {
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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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incomingTimeout-timeDelta, 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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// 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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// sender messed up, or an intermediate node tampered with the HTLC.
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if incomingTimeout-timeDelta < outgoingTimeout {
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l.errorf("Incoming htlc(%x) has incorrect time-lock value: "+
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"expected at least %v block delta, got %v block delta",
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payHash[:], timeDelta, incomingTimeout-outgoingTimeout)
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// Grab the latest routing policy so the sending node is up to
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// date with our current policy.
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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.NewIncorrectCltvExpiry(
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incomingTimeout, *update,
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)
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}
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return failure
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}
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return nil
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}
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@@ -2289,8 +2337,7 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
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needUpdate = true
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// There are additional channels left within this route. So
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// we'll verify that our forwarding constraints have been
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// properly met by this incoming HTLC.
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// we'll simply do some forwarding package book-keeping.
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default:
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// If hodl.AddIncoming is requested, we will not
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// validate the forwarded ADD, nor will we send the
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@@ -2332,14 +2379,16 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
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chanIterator.EncodeNextHop(buf)
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updatePacket := &htlcPacket{
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incomingChanID: l.ShortChanID(),
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incomingHTLCID: pd.HtlcIndex,
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outgoingChanID: fwdInfo.NextHop,
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sourceRef: pd.SourceRef,
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incomingAmount: pd.Amount,
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amount: addMsg.Amount,
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htlc: addMsg,
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obfuscator: obfuscator,
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incomingChanID: l.ShortChanID(),
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incomingHTLCID: pd.HtlcIndex,
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outgoingChanID: fwdInfo.NextHop,
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sourceRef: pd.SourceRef,
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incomingAmount: pd.Amount,
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amount: addMsg.Amount,
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htlc: addMsg,
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obfuscator: obfuscator,
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incomingTimeout: pd.Timeout,
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outgoingTimeout: fwdInfo.OutgoingCTLV,
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}
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switchPackets = append(
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switchPackets, updatePacket,
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@@ -2348,80 +2397,8 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
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continue
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}
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// We'll consult the forwarding policy for this link
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// when checking time locked related constraints.
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hopPolicy := l.cfg.FwrdingPolicy
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// We want to avoid forwarding an HTLC which will
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// expire in the near future, so we'll reject an HTLC
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// if its expiration time is too close to the current
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// height.
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timeDelta := hopPolicy.TimeLockDelta
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if pd.Timeout-timeDelta <= heightNow {
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log.Errorf("htlc(%x) has an expiry "+
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"that's too soon: outgoing_expiry=%v, "+
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"best_height=%v", pd.RHash[:],
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pd.Timeout-timeDelta, 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(
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update,
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)
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} else {
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failure = lnwire.NewExpiryTooSoon(*update)
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}
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator,
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pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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// Finally, we'll ensure that the time-lock on the
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// outgoing HTLC meets the following constraint: the
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// incoming time-lock minus our time-lock delta should
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// equal the outgoing time lock. Otherwise, whether the
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// sender messed up, or an intermediate node tampered
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// with the HTLC.
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if pd.Timeout-timeDelta < fwdInfo.OutgoingCTLV {
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log.Errorf("Incoming htlc(%x) has incorrect "+
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"time-lock value: expected at least "+
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"%v block delta, got %v block delta",
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pd.RHash[:], timeDelta,
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pd.Timeout-fwdInfo.OutgoingCTLV)
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// Grab the latest routing policy so the
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// sending node is up to date with our current
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// policy.
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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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l.fail(LinkFailureError{
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code: ErrInternalError},
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"unable to create channel "+
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"update while handling "+
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"the error: %v", err)
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return false
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}
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failure := lnwire.NewIncorrectCltvExpiry(
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pd.Timeout, *update)
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l.sendHTLCError(
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pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
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)
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needUpdate = true
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continue
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}
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// TODO(roasbeef): also add max timeout value
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// TODO(roasbeef): ensure don't accept outrageous
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// timeout for htlc
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// With all our forwarding constraints met, we'll
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// create the outgoing HTLC using the parameters as
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@@ -2470,14 +2447,16 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
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// section.
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if fwdPkg.State == channeldb.FwdStateLockedIn {
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updatePacket := &htlcPacket{
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incomingChanID: l.ShortChanID(),
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incomingHTLCID: pd.HtlcIndex,
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outgoingChanID: fwdInfo.NextHop,
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sourceRef: pd.SourceRef,
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incomingAmount: pd.Amount,
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amount: addMsg.Amount,
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htlc: addMsg,
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obfuscator: obfuscator,
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incomingChanID: l.ShortChanID(),
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incomingHTLCID: pd.HtlcIndex,
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outgoingChanID: fwdInfo.NextHop,
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sourceRef: pd.SourceRef,
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incomingAmount: pd.Amount,
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amount: addMsg.Amount,
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htlc: addMsg,
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obfuscator: obfuscator,
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incomingTimeout: pd.Timeout,
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outgoingTimeout: fwdInfo.OutgoingCTLV,
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}
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fwdPkg.FwdFilter.Set(idx)
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