channeldb/invoices: update AMP invoice htlcs

channeldb/invoice_test.go

@@ -1421,6 +1421,23 @@ func TestSetIDIndex(t *testing.T) {
 	require.Nil(t, err)
 	require.Equal(t, invoice, &dbInvoiceBySetID)
 
+	// Now settle the first htlc set, asserting that the two htlcs with set
+	// id 2 get canceled as a result.
+	dbInvoice, err = db.UpdateInvoice(ref, getUpdateInvoiceAMPSettle(setID))
+	require.Nil(t, err)
+
+	invoice.State = ContractSettled
+	invoice.SettleDate = dbInvoice.SettleDate
+	invoice.SettleIndex = 1
+	invoice.AmtPaid = amt
+	invoice.Htlcs[CircuitKey{HtlcID: 0}].ResolveTime = time.Unix(1, 0)
+	invoice.Htlcs[CircuitKey{HtlcID: 0}].State = HtlcStateSettled
+	invoice.Htlcs[CircuitKey{HtlcID: 1}].ResolveTime = time.Unix(1, 0)
+	invoice.Htlcs[CircuitKey{HtlcID: 1}].State = HtlcStateCanceled
+	invoice.Htlcs[CircuitKey{HtlcID: 2}].ResolveTime = time.Unix(1, 0)
+	invoice.Htlcs[CircuitKey{HtlcID: 2}].State = HtlcStateCanceled
+	require.Equal(t, invoice, dbInvoice)
+
 	// Lastly, querying for an unknown set id should fail.
 	refUnknownSetID := InvoiceRefBySetID([32]byte{})
 	_, err = db.LookupInvoice(refUnknownSetID)
@@ -1484,6 +1501,24 @@ func updateAcceptAMPHtlc(id uint64, amt lnwire.MilliSatoshi,
 	}
 }
 
+func getUpdateInvoiceAMPSettle(setID *[32]byte) InvoiceUpdateCallback {
+	return func(invoice *Invoice) (*InvoiceUpdateDesc, error) {
+		if invoice.State == ContractSettled {
+			return nil, ErrInvoiceAlreadySettled
+		}
+
+		update := &InvoiceUpdateDesc{
+			State: &InvoiceStateUpdateDesc{
+				Preimage: nil,
+				NewState: ContractSettled,
+				SetID:    setID,
+			},
+		}
+
+		return update, nil
+	}
+}
+
 // TestDeleteInvoices tests that deleting a list of invoices will succeed
 // if all delete references are valid, or will fail otherwise.
 func TestDeleteInvoices(t *testing.T) {

channeldb/invoices.go

@@ -1753,6 +1753,11 @@ func (d *DB) updateInvoice(hash lntypes.Hash, invoices,
 		return &invoice, nil
 	}
 
+	var setID *[32]byte
+	if update.State != nil {
+		setID = update.State.SetID
+	}
+
 	now := d.clock.Now()
 
 	// Update invoice state if the update descriptor indicates an invoice
@@ -1847,7 +1852,7 @@ func (d *DB) updateInvoice(hash lntypes.Hash, invoices,
 		// The invoice state may have changed and this could have
 		// implications for the states of the individual htlcs. Align
 		// the htlc state with the current invoice state.
-		err := updateHtlc(now, htlc, invoice.State)
+		err := updateHtlc(now, htlc, invoice.State, setID)
 		if err != nil {
 			return nil, err
 		}
@@ -1908,19 +1913,47 @@ func updateInvoiceState(invoice *Invoice, hash lntypes.Hash,
 	// or canceled. The only restriction is on transitioning to settled
 	// where we ensure the preimage is valid.
 	case ContractOpen:
-		if update.NewState == ContractSettled {
-			// Validate preimage.
+		if update.NewState == ContractCanceled {
+			invoice.State = update.NewState
+			return nil
+		}
+
+		// For AMP invoices, there are no invoice-level preimage checks.
+		// However, we still sanity check that we aren't trying to
+		// settle an AMP invoice with a preimage.
+		if update.SetID != nil {
+			if update.Preimage != nil {
+				return errors.New("AMP set cannot have preimage")
+			}
+			invoice.State = update.NewState
+			return nil
+		}
+
 		switch {
+
+		// Validate the supplied preimage for non-AMP invoices.
 		case update.Preimage != nil:
 			if update.Preimage.Hash() != hash {
 				return ErrInvoicePreimageMismatch
 			}
 			invoice.Terms.PaymentPreimage = update.Preimage
 
-			case invoice.Terms.PaymentPreimage == nil:
+		// Permit non-AMP invoices to be accepted without knowing the
+		// preimage. When trying to settle we'll have to pass through
+		// the above check in order to not hit the one below.
+		case update.NewState == ContractAccepted:
+
+		// Fail if we still don't have a preimage when transitioning to
+		// settle the non-AMP invoice.
+		case update.NewState == ContractSettled &&
+			invoice.Terms.PaymentPreimage == nil:
+
 			return errors.New("unknown preimage")
 		}
-		}
+
+		invoice.State = update.NewState
+
+		return nil
 
 	// Once settled, we are in a terminal state.
 	case ContractSettled:
@@ -1933,10 +1966,6 @@ func updateInvoiceState(invoice *Invoice, hash lntypes.Hash,
 	default:
 		return errors.New("unknown state transition")
 	}
-
-	invoice.State = update.NewState
-
-	return nil
 }
 
 // cancelSingleHtlc validates cancelation of a single htlc and update its state.
@@ -1963,39 +1992,81 @@ func cancelSingleHtlc(resolveTime time.Time, htlc *InvoiceHTLC,
 
 // updateHtlc aligns the state of an htlc with the given invoice state.
 func updateHtlc(resolveTime time.Time, htlc *InvoiceHTLC,
-	invState ContractState) error {
+	invState ContractState, setID *[32]byte) error {
 
-	switch invState {
+	trySettle := func(persist bool) error {
+		if htlc.State != HtlcStateAccepted {
+			return nil
+		}
 
-	case ContractSettled:
-		if htlc.State == HtlcStateAccepted {
-			htlc.State = HtlcStateSettled
+		// Settle the HTLC if it matches the settled set id. Since we
+		// only allow settling of one HTLC set (for now) we cancel any
+		// that do not match the set id.
+		var htlcState HtlcState
+		if htlc.IsInHTLCSet(setID) {
+			// Non-AMP HTLCs can be settled immediately since we
+			// already know the preimage is valid due to checks at
+			// the invoice level. For AMP HTLCs, verify that the
+			// per-HTLC preimage-hash pair is valid.
+			if setID != nil && !htlc.AMP.Preimage.Matches(htlc.AMP.Hash) {
+				return fmt.Errorf("AMP preimage mismatch, "+
+					"preimage=%v hash=%v", *htlc.AMP.Preimage,
+					htlc.AMP.Hash)
+			}
+
+			htlcState = HtlcStateSettled
+		} else {
+			htlcState = HtlcStateCanceled
+		}
+
+		// Only persist the changes if the invoice is moving to the
+		// settled state.
+		if persist {
+			htlc.State = htlcState
 			htlc.ResolveTime = resolveTime
 		}
 
-	case ContractCanceled:
-		switch htlc.State {
-
-		case HtlcStateAccepted:
-			htlc.State = HtlcStateCanceled
-			htlc.ResolveTime = resolveTime
-
-		case HtlcStateSettled:
-			return fmt.Errorf("cannot have a settled htlc with " +
-				"invoice in state canceled")
+		return nil
 	}
 
-	case ContractOpen, ContractAccepted:
+	if invState == ContractSettled {
+		// Check that we can settle the HTLCs. For legacy and MPP HTLCs
+		// this will be a NOP, but for AMP HTLCs this asserts that we
+		// have a valid hash/preimage pair. Passing true permits the
+		// method to update the HTLC to HtlcStateSettled.
+		return trySettle(true)
+	}
+
+	// We should never find a settled HTLC on an invoice that isn't in
+	// ContractSettled.
 	if htlc.State == HtlcStateSettled {
 		return fmt.Errorf("cannot have a settled htlc with "+
 			"invoice in state %v", invState)
 	}
 
+	switch invState {
+
+	case ContractCanceled:
+		if htlc.State == HtlcStateAccepted {
+			htlc.State = HtlcStateCanceled
+			htlc.ResolveTime = resolveTime
+		}
+		return nil
+
+	case ContractAccepted:
+		// Check that we can settle the HTLCs. For legacy and MPP HTLCs
+		// this will be a NOP, but for AMP HTLCs this asserts that we
+		// have a valid hash/preimage pair. Passing false prevents the
+		// method from putting the HTLC in HtlcStateSettled, leaving it
+		// in HtlcStateAccepted.
+		return trySettle(false)
+
+	case ContractOpen:
+		return nil
+
 	default:
 		return errors.New("unknown state transition")
 	}
-
-	return nil
 }
 
 // setSettleMetaFields updates the metadata associated with settlement of an