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https://github.com/lightningnetwork/lnd.git
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htlcswitch: handle forwarding settle and fail seperately
This commit adds two methods, `handlePacketFail` and `handlePacketSettle` to handle the settle and fail packets differently.
This commit is contained in:
yyforyongyu
yyforyongyu
parent
6cb374aea6
commit
2fc79d8946
@ -1099,118 +1099,26 @@ func (s *Switch) parseFailedPayment(deobfuscator ErrorDecrypter,
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// updates back. This behaviour is achieved by creation of payment circuits.
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func (s *Switch) handlePacketForward(packet *htlcPacket) error {
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switch htlc := packet.htlc.(type) {
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// Channel link forwarded us a new htlc, therefore we initiate the
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// payment circuit within our internal state so we can properly forward
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// the ultimate settle message back latter.
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case *lnwire.UpdateAddHTLC:
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return s.handlePacketAdd(packet, htlc)
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case *lnwire.UpdateFailHTLC, *lnwire.UpdateFulfillHTLC:
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// If the source of this packet has not been set, use the
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// circuit map to lookup the origin.
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circuit, err := s.closeCircuit(packet)
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if err != nil {
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return err
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}
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case *lnwire.UpdateFulfillHTLC:
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return s.handlePacketSettle(packet)
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// closeCircuit returns a nil circuit when a settle packet returns an
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// ErrUnknownCircuit error upon the inner call to CloseCircuit.
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if circuit == nil {
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return nil
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}
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fail, isFail := htlc.(*lnwire.UpdateFailHTLC)
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if isFail && !packet.hasSource {
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// HTLC resolutions and messages restored from disk
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// don't have the obfuscator set from the original htlc
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// add packet - set it here for use in blinded errors.
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packet.obfuscator = circuit.ErrorEncrypter
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switch {
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// No message to encrypt, locally sourced payment.
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case circuit.ErrorEncrypter == nil:
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// If this is a resolution message, then we'll need to
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// encrypt it as it's actually internally sourced.
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case packet.isResolution:
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var err error
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// TODO(roasbeef): don't need to pass actually?
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failure := &lnwire.FailPermanentChannelFailure{}
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fail.Reason, err = circuit.ErrorEncrypter.EncryptFirstHop(
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failure,
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)
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if err != nil {
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err = fmt.Errorf("unable to obfuscate "+
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"error: %v", err)
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log.Error(err)
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}
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// Alternatively, if the remote party send us an
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// UpdateFailMalformedHTLC, then we'll need to convert
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// this into a proper well formatted onion error as
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// there's no HMAC currently.
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case packet.convertedError:
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log.Infof("Converting malformed HTLC error "+
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"for circuit for Circuit(%x: "+
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"(%s, %d) <-> (%s, %d))", packet.circuit.PaymentHash,
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packet.incomingChanID, packet.incomingHTLCID,
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packet.outgoingChanID, packet.outgoingHTLCID)
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fail.Reason = circuit.ErrorEncrypter.EncryptMalformedError(
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fail.Reason,
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)
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default:
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// Otherwise, it's a forwarded error, so we'll perform a
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// wrapper encryption as normal.
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fail.Reason = circuit.ErrorEncrypter.IntermediateEncrypt(
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fail.Reason,
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)
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}
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} else if !isFail && circuit.Outgoing != nil {
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// If this is an HTLC settle, and it wasn't from a
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// locally initiated HTLC, then we'll log a forwarding
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// event so we can flush it to disk later.
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//
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// TODO(roasbeef): only do this once link actually
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// fully settles?
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localHTLC := packet.incomingChanID == hop.Source
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if !localHTLC {
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log.Infof("Forwarded HTLC(%x) of %v (fee: %v) "+
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"from IncomingChanID(%v) to OutgoingChanID(%v)",
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circuit.PaymentHash[:], circuit.OutgoingAmount,
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circuit.IncomingAmount-circuit.OutgoingAmount,
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circuit.Incoming.ChanID, circuit.Outgoing.ChanID)
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s.fwdEventMtx.Lock()
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s.pendingFwdingEvents = append(
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s.pendingFwdingEvents,
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channeldb.ForwardingEvent{
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Timestamp: time.Now(),
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IncomingChanID: circuit.Incoming.ChanID,
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OutgoingChanID: circuit.Outgoing.ChanID,
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AmtIn: circuit.IncomingAmount,
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AmtOut: circuit.OutgoingAmount,
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},
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)
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s.fwdEventMtx.Unlock()
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}
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}
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// A blank IncomingChanID in a circuit indicates that it is a pending
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// user-initiated payment.
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if packet.incomingChanID == hop.Source {
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s.wg.Add(1)
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go s.handleLocalResponse(packet)
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return nil
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}
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// Check to see that the source link is online before removing
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// the circuit.
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return s.mailOrchestrator.Deliver(packet.incomingChanID, packet)
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// Channel link forwarded us an update_fail_htlc message.
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//
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// NOTE: when the channel link receives an update_fail_malformed_htlc
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// from upstream, it will convert the message into update_fail_htlc and
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// forward it. Thus there's no need to catch `UpdateFailMalformedHTLC`
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// here.
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case *lnwire.UpdateFailHTLC:
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return s.handlePacketFail(packet, htlc)
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default:
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return errors.New("wrong update type")
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return fmt.Errorf("wrong update type: %T", htlc)
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}
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}
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@ -3051,3 +2959,161 @@ func (s *Switch) handlePacketAdd(packet *htlcPacket,
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return destination.handleSwitchPacket(packet)
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}
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// handlePacketSettle handles forwarding a settle packet.
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func (s *Switch) handlePacketSettle(packet *htlcPacket) error {
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// If the source of this packet has not been set, use the circuit map
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// to lookup the origin.
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circuit, err := s.closeCircuit(packet)
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if err != nil {
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return err
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}
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// closeCircuit returns a nil circuit when a settle packet returns an
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// ErrUnknownCircuit error upon the inner call to CloseCircuit.
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//
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// NOTE: We can only get a nil circuit when it has already been deleted
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// and when `UpdateFulfillHTLC` is received. After which `RevokeAndAck`
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// is received, which invokes `processRemoteSettleFails` in its link.
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if circuit == nil {
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log.Debugf("Found nil circuit: packet=%v", spew.Sdump(packet))
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return nil
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}
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localHTLC := packet.incomingChanID == hop.Source
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// If this is a locally initiated HTLC, we need to handle the packet by
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// storing the network result.
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//
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// A blank IncomingChanID in a circuit indicates that it is a pending
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// user-initiated payment.
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//
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// NOTE: `closeCircuit` modifies the state of `packet`.
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if localHTLC {
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// TODO(yy): remove the goroutine and send back the error here.
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s.wg.Add(1)
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go s.handleLocalResponse(packet)
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// If this is a locally initiated HTLC, there's no need to
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// forward it so we exit.
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return nil
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}
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// If this is an HTLC settle, and it wasn't from a locally initiated
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// HTLC, then we'll log a forwarding event so we can flush it to disk
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// later.
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if circuit.Outgoing != nil {
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log.Infof("Forwarded HTLC(%x) of %v (fee: %v) "+
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"from IncomingChanID(%v) to OutgoingChanID(%v)",
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circuit.PaymentHash[:], circuit.OutgoingAmount,
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circuit.IncomingAmount-circuit.OutgoingAmount,
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circuit.Incoming.ChanID, circuit.Outgoing.ChanID)
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s.fwdEventMtx.Lock()
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s.pendingFwdingEvents = append(
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s.pendingFwdingEvents,
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channeldb.ForwardingEvent{
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Timestamp: time.Now(),
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IncomingChanID: circuit.Incoming.ChanID,
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OutgoingChanID: circuit.Outgoing.ChanID,
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AmtIn: circuit.IncomingAmount,
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AmtOut: circuit.OutgoingAmount,
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},
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)
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s.fwdEventMtx.Unlock()
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}
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// Deliver this packet.
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return s.mailOrchestrator.Deliver(packet.incomingChanID, packet)
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}
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// handlePacketFail handles forwarding a fail packet.
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func (s *Switch) handlePacketFail(packet *htlcPacket,
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htlc *lnwire.UpdateFailHTLC) error {
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// If the source of this packet has not been set, use the circuit map
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// to lookup the origin.
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circuit, err := s.closeCircuit(packet)
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if err != nil {
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return err
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}
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// If this is a locally initiated HTLC, we need to handle the packet by
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// storing the network result.
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//
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// A blank IncomingChanID in a circuit indicates that it is a pending
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// user-initiated payment.
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//
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// NOTE: `closeCircuit` modifies the state of `packet`.
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if packet.incomingChanID == hop.Source {
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// TODO(yy): remove the goroutine and send back the error here.
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s.wg.Add(1)
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go s.handleLocalResponse(packet)
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// If this is a locally initiated HTLC, there's no need to
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// forward it so we exit.
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return nil
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}
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// Exit early if this hasSource is true. This flag is only set via
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// mailbox's `FailAdd`. This method has two callsites,
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// - the packet has timed out after `MailboxDeliveryTimeout`, defaults
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// to 1 min.
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// - the HTLC fails the validation in `channel.AddHTLC`.
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// In either case, the `Reason` field is populated. Thus there's no
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// need to proceed and extract the failure reason below.
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if packet.hasSource {
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// Deliver this packet.
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return s.mailOrchestrator.Deliver(packet.incomingChanID, packet)
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}
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// HTLC resolutions and messages restored from disk don't have the
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// obfuscator set from the original htlc add packet - set it here for
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// use in blinded errors.
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packet.obfuscator = circuit.ErrorEncrypter
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switch {
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// No message to encrypt, locally sourced payment.
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case circuit.ErrorEncrypter == nil:
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// TODO(yy) further check this case as we shouldn't end up here
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// as `isLocal` is already false.
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// If this is a resolution message, then we'll need to encrypt it as
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// it's actually internally sourced.
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case packet.isResolution:
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var err error
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// TODO(roasbeef): don't need to pass actually?
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failure := &lnwire.FailPermanentChannelFailure{}
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htlc.Reason, err = circuit.ErrorEncrypter.EncryptFirstHop(
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failure,
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)
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if err != nil {
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err = fmt.Errorf("unable to obfuscate error: %w", err)
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log.Error(err)
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}
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// Alternatively, if the remote party sends us an
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// UpdateFailMalformedHTLC, then we'll need to convert this into a
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// proper well formatted onion error as there's no HMAC currently.
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case packet.convertedError:
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log.Infof("Converting malformed HTLC error for circuit for "+
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"Circuit(%x: (%s, %d) <-> (%s, %d))",
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packet.circuit.PaymentHash,
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packet.incomingChanID, packet.incomingHTLCID,
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packet.outgoingChanID, packet.outgoingHTLCID)
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htlc.Reason = circuit.ErrorEncrypter.EncryptMalformedError(
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htlc.Reason,
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)
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default:
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// Otherwise, it's a forwarded error, so we'll perform a
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// wrapper encryption as normal.
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htlc.Reason = circuit.ErrorEncrypter.IntermediateEncrypt(
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htlc.Reason,
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)
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}
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// Deliver this packet.
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return s.mailOrchestrator.Deliver(packet.incomingChanID, packet)
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}
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