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htlcswitch: eliminate unnecessary indentation in processRemoteAdds 

In this commit, we remove a ton of unnecessary indentation in the
processRemoteAdds method. Before this commit, we had a switch statement
on the type of the entry. This was required before when the method was
generic, but now since we already know that it’s an Add, we no longer
require such a statement.
This commit is contained in:
Olaoluwa Osuntokun 2018-03-12 18:55:04 -07:00
parent 069311c47f
commit 8988a07bce
No known key found for this signature in database
GPG Key ID: 964EA263DD637C21
1 changed files with 430 additions and 443 deletions
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873
htlcswitch/link.go
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@ -1812,438 +1812,258 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
continue
}
// TODO(roasbeef): rework log entries to a shared
// interface.
switch pd.EntryType {
// 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).
case lnwallet.Add:
// 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
// Fetch the onion blob that was included within this processed
// payment descriptor.
var onionBlob [lnwire.OnionPacketSize]byte
copy(onionBlob[:], pd.OnionBlob)
log.Errorf("unable to decode onion hop "+
"iterator: %v", failureCode)
// 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.DecodeOnionObfuscator,
)
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.bestHeight
fwdInfo := chanIterator.ForwardingInstructions()
switch fwdInfo.NextHop {
case exitHop:
if l.cfg.DebugHTLC && l.cfg.HodlHTLC {
log.Warnf("hodl HTLC mode enabled, will not " +
"attempt to settle HTLC with sender")
continue
}
// Retrieve onion obfuscator from onion blob in order
// to produce initial obfuscation of the onion
// failureCode.
obfuscator, failureCode := chanIterator.ExtractErrorEncrypter(
l.cfg.DecodeOnionObfuscator,
)
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
// 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)
log.Errorf("unable to decode onion "+
"obfuscator: %v", failureCode)
failure := lnwire.FailFinalIncorrectCltvExpiry{}
l.sendHTLCError(
pd.HtlcIndex, &failure, obfuscator, pd.SourceRef,
)
needUpdate = true
continue
}
heightNow := l.bestHeight
fwdInfo := chanIterator.ForwardingInstructions()
switch fwdInfo.NextHop {
case exitHop:
if l.cfg.DebugHTLC && l.cfg.HodlHTLC {
log.Warnf("hodl HTLC mode enabled, " +
"will not attempt to settle " +
"HTLC with sender")
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.FailFinalIncorrectCltvExpiry{}
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, 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 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.
//
// TODO(roasbeef): also accept global default?
expectedHeight := heightNow + l.cfg.FwrdingPolicy.TimeLockDelta
if !l.cfg.DebugHTLC {
switch {
case 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 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("unable to settle htlc: %v", err)
return false
}
// Notify the invoiceRegistry of the invoices we
// just settled with this latest commitment
// update.
err = l.cfg.Registry.SettleInvoice(invoiceHash)
if err != nil {
l.fail("unable to settle invoice: %v", err)
return false
}
l.infof("Settling %x as exit hop", pd.RHash)
// HTLC was successfully settled locally send
// notification about it remote peer.
l.cfg.Peer.SendMessage(&lnwire.UpdateFulfillHTLC{
ChanID: l.ChanID(),
ID: pd.HtlcIndex,
PaymentPreimage: preimage,
})
needUpdate = true
// There are additional channels left within this
// route. So we'll verify that our forwarding
// constraints have been properly met by by this
// incoming HTLC.
default:
switch fwdPkg.State {
case channeldb.FwdStateProcessed:
if !fwdPkg.FwdFilter.Contains(idx) {
// 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.
break
}
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,
}
switchPackets = append(switchPackets,
updatePacket)
continue
}
// We want to avoid forwarding 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 := l.cfg.FwrdingPolicy.TimeLockDelta
if pd.Timeout-timeDelta <= heightNow {
log.Errorf("htlc(%x) has an expiry "+
"that's too soon: outgoing_expiry=%v, "+
"best_height=%v", pd.RHash[:],
pd.Timeout-timeDelta, heightNow)
var failure lnwire.FailureMessage
update, err := l.cfg.GetLastChannelUpdate()
if err != nil {
failure = lnwire.NewTemporaryChannelFailure(nil)
} else {
failure = lnwire.NewExpiryTooSoon(*update)
}
l.sendHTLCError(pd.HtlcIndex, failure,
obfuscator, pd.SourceRef)
needUpdate = true
continue
}
// As our second sanity check, we'll ensure that
// the passed HTLC isn't too small. If so, then
// we'll cancel the HTLC directly.
if pd.Amount < l.cfg.FwrdingPolicy.MinHTLC {
log.Errorf("Incoming htlc(%x) is too "+
"small: min_htlc=%v, htlc_value=%v",
pd.RHash[:], l.cfg.FwrdingPolicy.MinHTLC,
pd.Amount)
// 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.GetLastChannelUpdate()
if err != nil {
failure = lnwire.NewTemporaryChannelFailure(nil)
} else {
failure = lnwire.NewAmountBelowMinimum(
pd.Amount, *update)
}
l.sendHTLCError(pd.HtlcIndex, failure,
obfuscator, pd.SourceRef)
needUpdate = true
continue
}
// Next, using the amount of the incoming HTLC,
// we'll calculate the expected fee this
// incoming HTLC must carry in order to be
// accepted.
expectedFee := ExpectedFee(
l.cfg.FwrdingPolicy,
fwdInfo.AmountToForward,
// 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, 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,
)
// 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 := pd.Amount - fwdInfo.AmountToForward
if pd.Amount < fwdInfo.AmountToForward ||
actualFee < expectedFee {
needUpdate = true
continue
}
log.Errorf("Incoming htlc(%x) has "+
"insufficient fee: expected "+
"%v, got %v", pd.RHash[:],
int64(expectedFee),
int64(pd.Amount-fwdInfo.AmountToForward))
// 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 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[:])
}
// 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.GetLastChannelUpdate()
if err != nil {
failure = lnwire.NewTemporaryChannelFailure(nil)
} else {
failure = lnwire.NewFeeInsufficient(pd.Amount,
*update)
}
// 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 {
l.sendHTLCError(pd.HtlcIndex, failure,
obfuscator, pd.SourceRef)
needUpdate = true
continue
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.
//
// TODO(roasbeef): also accept global default?
expectedHeight := heightNow + l.cfg.FwrdingPolicy.TimeLockDelta
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("unable to settle htlc: %v", err)
return false
}
// Notify the invoiceRegistry of the invoices we just
// settled with this latest commitment update.
err = l.cfg.Registry.SettleInvoice(invoiceHash)
if err != nil {
l.fail("unable to settle invoice: %v", err)
return false
}
l.infof("settling %x as exit hop", pd.RHash)
// HTLC was successfully settled locally send
// notification about it remote peer.
l.cfg.Peer.SendMessage(&lnwire.UpdateFulfillHTLC{
ChanID: l.ChanID(),
ID: pd.HtlcIndex,
PaymentPreimage: preimage,
})
needUpdate = true
// There are additional channels left within this route. So
// we'll verify that our forwarding constraints have been
// properly met by by this incoming HTLC.
default:
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
}
// 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 pd.Timeout-timeDelta < fwdInfo.OutgoingCTLV {
log.Errorf("Incoming htlc(%x) has "+
"incorrect time-lock value: "+
"expected at least %v block delta, "+
"got %v block delta", pd.RHash[:],
timeDelta,
pd.Timeout-fwdInfo.OutgoingCTLV)
// Grab the latest routing policy so
// the sending node is up to date with
// our current policy.
update, err := l.cfg.GetLastChannelUpdate()
if err != nil {
l.fail("unable to create channel update "+
"while handling the error: %v", err)
return false
}
failure := lnwire.NewIncorrectCltvExpiry(
pd.Timeout, *update)
l.sendHTLCError(pd.HtlcIndex, failure,
obfuscator, pd.SourceRef)
needUpdate = true
continue
}
// TODO(roasbeef): also add max timeout value
// With all our forwarding constraints met,
// we'll create the outgoing HTLC using the
// parameters as specified in the forwarding
// info.
// Otherwise, it was already processed, we can
// can collect it and continue.
addMsg := &lnwire.UpdateAddHTLC{
Expiry: fwdInfo.OutgoingCTLV,
Amount: fwdInfo.AmountToForward,
@ -2254,43 +2074,210 @@ func (l *channelLink) processRemoteAdds(fwdPkg *channeldb.FwdPkg,
// the _next_ hop using the hop iterator
// decoded for the current hop.
buf := bytes.NewBuffer(addMsg.OnionBlob[0:0])
err := chanIterator.EncodeNextHop(buf)
// 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,
}
switchPackets = append(switchPackets,
updatePacket)
continue
}
// We want to avoid forwarding 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 := l.cfg.FwrdingPolicy.TimeLockDelta
if pd.Timeout-timeDelta <= heightNow {
log.Errorf("htlc(%x) has an expiry "+
"that's too soon: outgoing_expiry=%v, "+
"best_height=%v", pd.RHash[:],
pd.Timeout-timeDelta, heightNow)
var failure lnwire.FailureMessage
update, err := l.cfg.GetLastChannelUpdate()
if err != nil {
log.Errorf("unable to encode the "+
"remaining route %v", err)
failure := lnwire.NewTemporaryChannelFailure(nil)
l.sendHTLCError(pd.HtlcIndex, failure,
obfuscator, pd.SourceRef)
needUpdate = true
continue
failure = lnwire.NewTemporaryChannelFailure(nil)
} else {
failure = lnwire.NewExpiryTooSoon(*update)
}
// 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,
}
l.sendHTLCError(
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
)
needUpdate = true
continue
}
fwdPkg.FwdFilter.Set(idx)
switchPackets = append(switchPackets,
updatePacket)
// As our second sanity check, we'll ensure that the
// passed HTLC isn't too small. If so, then
// we'll cancel the HTLC directly.
if pd.Amount < l.cfg.FwrdingPolicy.MinHTLC {
log.Errorf("Incoming htlc(%x) is too "+
"small: min_htlc=%v, htlc_value=%v",
pd.RHash[:], l.cfg.FwrdingPolicy.MinHTLC,
pd.Amount)
// 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.GetLastChannelUpdate()
if err != nil {
failure = lnwire.NewTemporaryChannelFailure(nil)
} else {
failure = lnwire.NewAmountBelowMinimum(
pd.Amount, *update)
}
l.sendHTLCError(
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
)
needUpdate = true
continue
}
// Next, using the amount of the incoming HTLC, we'll
// calculate the expected fee this incoming HTLC must
// carry in order to be accepted.
expectedFee := ExpectedFee(
l.cfg.FwrdingPolicy,
fwdInfo.AmountToForward,
)
// 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 := pd.Amount - fwdInfo.AmountToForward
if pd.Amount < fwdInfo.AmountToForward ||
actualFee < expectedFee {
log.Errorf("Incoming htlc(%x) has insufficient "+
"fee: expected %v, got %v", pd.RHash[:],
int64(expectedFee),
int64(pd.Amount-fwdInfo.AmountToForward))
// 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.GetLastChannelUpdate()
if err != nil {
failure = lnwire.NewTemporaryChannelFailure(nil)
} else {
failure = lnwire.NewFeeInsufficient(pd.Amount,
*update)
}
l.sendHTLCError(
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
)
needUpdate = true
continue
}
// 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 pd.Timeout-timeDelta < fwdInfo.OutgoingCTLV {
log.Errorf("Incoming htlc(%x) has incorrect "+
"time-lock value: expected at least "+
"%v block delta, got %v block delta",
pd.RHash[:], timeDelta,
pd.Timeout-fwdInfo.OutgoingCTLV)
// Grab the latest routing policy so the
// sending node is up to date with our current
// policy.
update, err := l.cfg.GetLastChannelUpdate()
if err != nil {
l.fail("unable to create channel update "+
"while handling the error: %v", err)
return false
}
failure := lnwire.NewIncorrectCltvExpiry(
pd.Timeout, *update)
l.sendHTLCError(
pd.HtlcIndex, failure, obfuscator, pd.SourceRef,
)
needUpdate = true
continue
}
// TODO(roasbeef): also add max timeout value
// 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)
failure := lnwire.NewTemporaryChannelFailure(nil)
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,
}
fwdPkg.FwdFilter.Set(idx)
switchPackets = append(switchPackets,
updatePacket)
}
}
}