Merge pull request #784 from halseth/protocol-errors

Wire protocol errors

fundingmanager.go

@@ -689,21 +689,40 @@ func (f *fundingManager) CancelPeerReservations(nodePub [33]byte) {
 }
 
 // failFundingFlow will fail the active funding flow with the target peer,
-// identified by its unique temporary channel ID. This method is send an error
+// identified by its unique temporary channel ID. This method will send an
-// to the remote peer, and also remove the reservation from our set of pending
+// error to the remote peer, and also remove the reservation from our set of
-// reservations.
+// pending reservations.
 //
 // TODO(roasbeef): if peer disconnects, and haven't yet broadcast funding
 // transaction, then all reservations should be cleared.
 func (f *fundingManager) failFundingFlow(peer *btcec.PublicKey,
-	tempChanID [32]byte, msg []byte) {
+	tempChanID [32]byte, fundingErr error) {
+
+	// We only send the exact error if it is part of out whitelisted set of
+	// errors (lnwire.ErrorCode or lnwallet.ReservationError).
+	var msg lnwire.ErrorData
+	switch e := fundingErr.(type) {
+
+	// Let the actual error message be sent to the remote.
+	case lnwallet.ReservationError:
+		msg = lnwire.ErrorData(e.Error())
+
+	// Send the status code.
+	case lnwire.ErrorCode:
+		msg = lnwire.ErrorData{byte(e)}
+
+	// We just send a generic error.
+	default:
+		msg = lnwire.ErrorData("funding failed due to internal error")
+	}
 
 	errMsg := &lnwire.Error{
 		ChanID: tempChanID,
 		Data:   msg,
 	}
 
-	fndgLog.Errorf("Failing funding flow: %v", spew.Sdump(errMsg))
+	fndgLog.Errorf("Failing funding flow: %v (%v)", fundingErr,
+		spew.Sdump(errMsg))
 
 	if _, err := f.cancelReservationCtx(peer, tempChanID); err != nil {
 		fndgLog.Errorf("unable to cancel reservation: %v", err)
@@ -819,8 +838,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 	if len(f.activeReservations[peerIDKey]) >= cfg.MaxPendingChannels {
 		f.failFundingFlow(
 			fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID,
-			lnwire.ErrorData{byte(lnwire.ErrMaxPendingChannels)},
+			lnwire.ErrMaxPendingChannels)
-		)
 		return
 	}
 
@@ -834,8 +852,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 		}
 		f.failFundingFlow(
 			fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID,
-			lnwire.ErrorData{byte(lnwire.ErrSynchronizingChain)},
+			lnwire.ErrSynchronizingChain)
-		)
 		return
 	}
 
@@ -844,8 +861,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 	if msg.FundingAmount > maxFundingAmount {
 		f.failFundingFlow(
 			fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID,
-			lnwire.ErrorData{byte(lnwire.ErrChanTooLarge)},
+			lnwire.ErrChanTooLarge)
-		)
 		return
 	}
 
@@ -871,7 +887,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 	if err != nil {
 		fndgLog.Errorf("Unable to initialize reservation: %v", err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			msg.PendingChannelID, []byte(err.Error()))
+			msg.PendingChannelID, err)
 		return
 	}
 
@@ -890,10 +906,9 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 		msg.MaxValueInFlight, msg.HtlcMinimum, msg.ChannelReserve,
 	)
 	if err != nil {
-		f.failFundingFlow(
+		fndgLog.Errorf("Unaccaptable channel constraints: %v", err)
-			fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID,
+		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			[]byte(fmt.Sprintf("Unacceptable channel "+
+			fmsg.msg.PendingChannelID, err,
-				"constraints: %v", err)),
 		)
 		return
 	}
@@ -951,9 +966,8 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 	err = reservation.ProcessSingleContribution(remoteContribution)
 	if err != nil {
 		fndgLog.Errorf("unable to add contribution reservation: %v", err)
-		// TODO(roasbeef): verify only sending sane info over
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			msg.PendingChannelID, []byte(err.Error()))
+			msg.PendingChannelID, err)
 		return
 	}
 
@@ -985,7 +999,7 @@ func (f *fundingManager) handleFundingOpen(fmsg *fundingOpenMsg) {
 	if err != nil {
 		fndgLog.Errorf("unable to send funding response to peer: %v", err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			msg.PendingChannelID, []byte(err.Error()))
+			msg.PendingChannelID, err)
 		return
 	}
 }
@@ -1028,11 +1042,9 @@ func (f *fundingManager) handleFundingAccept(fmsg *fundingAcceptMsg) {
 		msg.MaxValueInFlight, msg.HtlcMinimum, msg.ChannelReserve,
 	)
 	if err != nil {
-		f.failFundingFlow(
+		fndgLog.Warnf("Unacceptable channel constraints: %v", err)
-			fmsg.peerAddress.IdentityKey, fmsg.msg.PendingChannelID,
+		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			[]byte(fmt.Sprintf("Unacceptable channel "+
+			fmsg.msg.PendingChannelID, err)
-				"constraints: %v", err)),
-		)
 		return
 	}
 
@@ -1070,7 +1082,7 @@ func (f *fundingManager) handleFundingAccept(fmsg *fundingAcceptMsg) {
 		fndgLog.Errorf("Unable to process contribution from %v: %v",
 			fmsg.peerAddress.IdentityKey, err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			msg.PendingChannelID, []byte(err.Error()))
+			msg.PendingChannelID, err)
 		resCtx.err <- err
 		return
 	}
@@ -1115,7 +1127,7 @@ func (f *fundingManager) handleFundingAccept(fmsg *fundingAcceptMsg) {
 	if err != nil {
 		fndgLog.Errorf("Unable to parse signature: %v", err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			msg.PendingChannelID, []byte(err.Error()))
+			msg.PendingChannelID, err)
 		resCtx.err <- err
 		return
 	}
@@ -1123,7 +1135,7 @@ func (f *fundingManager) handleFundingAccept(fmsg *fundingAcceptMsg) {
 	if err != nil {
 		fndgLog.Errorf("Unable to send funding complete message: %v", err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			msg.PendingChannelID, []byte(err.Error()))
+			msg.PendingChannelID, err)
 		resCtx.err <- err
 		return
 	}
@@ -1177,7 +1189,7 @@ func (f *fundingManager) handleFundingCreated(fmsg *fundingCreatedMsg) {
 		// TODO(roasbeef): better error logging: peerID, channelID, etc.
 		fndgLog.Errorf("unable to complete single reservation: %v", err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			pendingChanID, []byte(err.Error()))
+			pendingChanID, err)
 		return
 	}
 
@@ -1218,7 +1230,7 @@ func (f *fundingManager) handleFundingCreated(fmsg *fundingCreatedMsg) {
 	if err != nil {
 		fndgLog.Errorf("unable to parse signature: %v", err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			pendingChanID, []byte(err.Error()))
+			pendingChanID, err)
 		deleteFromDatabase()
 		return
 	}
@@ -1230,7 +1242,7 @@ func (f *fundingManager) handleFundingCreated(fmsg *fundingCreatedMsg) {
 	if err := f.cfg.SendToPeer(peerKey, fundingSigned); err != nil {
 		fndgLog.Errorf("unable to send FundingSigned message: %v", err)
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			pendingChanID, []byte(err.Error()))
+			pendingChanID, err)
 		deleteFromDatabase()
 		return
 	}
@@ -1332,11 +1344,12 @@ func (f *fundingManager) handleFundingSigned(fmsg *fundingSignedMsg) {
 	delete(f.signedReservations, fmsg.msg.ChanID)
 	f.resMtx.Unlock()
 	if !ok {
-		err := fmt.Sprintf("Unable to find signed reservation for "+
+		err := fmt.Errorf("Unable to find signed reservation for "+
 			"chan_id=%x", fmsg.msg.ChanID)
-		fndgLog.Warnf(err)
+		fndgLog.Warnf(err.Error())
+		// TODO: add ErrChanNotFound?
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			pendingChanID, []byte(err))
+			pendingChanID, err)
 		return
 	}
 
@@ -1346,8 +1359,9 @@ func (f *fundingManager) handleFundingSigned(fmsg *fundingSignedMsg) {
 	if err != nil {
 		fndgLog.Warnf("Unable to find reservation (peerID:%v, chanID:%x)",
 			peerKey, pendingChanID[:])
+		// TODO: add ErrChanNotFound?
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			pendingChanID, []byte(err.Error()))
+			pendingChanID, err)
 		return
 	}
 
@@ -1369,7 +1383,7 @@ func (f *fundingManager) handleFundingSigned(fmsg *fundingSignedMsg) {
 		fndgLog.Errorf("Unable to complete reservation sign complete: %v", err)
 		resCtx.err <- err
 		f.failFundingFlow(fmsg.peerAddress.IdentityKey,
-			pendingChanID, []byte(err.Error()))
+			pendingChanID, err)
 		return
 	}
 

lnwallet/errors.go

@@ -0,0 +1,108 @@
+package lnwallet
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/roasbeef/btcd/chaincfg/chainhash"
+	"github.com/roasbeef/btcutil"
+)
+
+// ReservationError wraps certain errors returned during channel reservation
+// that can be sent across the wire to the remote peer. Errors not being
+// ReservationErrors will not be sent to the remote in case of a failed channel
+// reservation, as they may contain private information.
+type ReservationError struct {
+	error
+}
+
+// A compile time check to ensure ReservationError implements the error
+// interface.
+var _ error = (*ReservationError)(nil)
+
+// ErrZeroCapacity returns an error indicating the funder attempted to put zero
+// funds into the channel.
+func ErrZeroCapacity() ReservationError {
+	return ReservationError{
+		errors.New("zero channel funds"),
+	}
+}
+
+// ErrChainMismatch returns an error indicating that the initiator tried to
+// open a channel for an unknown chain.
+func ErrChainMismatch(knownChain,
+	unknownChain *chainhash.Hash) ReservationError {
+	return ReservationError{
+		fmt.Errorf("Unknown chain=%v. Supported chain=%v",
+			unknownChain, knownChain),
+	}
+}
+
+// ErrFunderBalanceDust returns an error indicating the initial balance of the
+// funder is considered dust at the current commitment fee.
+func ErrFunderBalanceDust(commitFee, funderBalance,
+	minBalance int64) ReservationError {
+	return ReservationError{
+		fmt.Errorf("Funder balance too small (%v) with fee=%v sat, "+
+			"minimum=%v sat required", funderBalance,
+			commitFee, minBalance),
+	}
+}
+
+// ErrCsvDelayTooLarge returns an error indicating that the CSV delay was to
+// large to be accepted, along with the current max.
+func ErrCsvDelayTooLarge(remoteDelay, maxDelay uint16) ReservationError {
+	return ReservationError{
+		fmt.Errorf("CSV delay too large: %v, max is %v",
+			remoteDelay, maxDelay),
+	}
+}
+
+// ErrChanReserveTooLarge returns an error indicating that the chan reserve the
+// remote is requiring, is too large to be accepted.
+func ErrChanReserveTooLarge(reserve,
+	maxReserve btcutil.Amount) ReservationError {
+	return ReservationError{
+		fmt.Errorf("Channel reserve is too large: %v sat, max "+
+			"is %v sat", int64(reserve), int64(maxReserve)),
+	}
+}
+
+// ErrMinHtlcTooLarge returns an error indicating that the MinHTLC value the
+// remote required is too large to be accepted.
+func ErrMinHtlcTooLarge(minHtlc,
+	maxMinHtlc lnwire.MilliSatoshi) ReservationError {
+	return ReservationError{
+		fmt.Errorf("Minimum HTLC value is too large: %v, max is %v",
+			minHtlc, maxMinHtlc),
+	}
+}
+
+// ErrMaxHtlcNumTooLarge returns an error indicating that the 'max HTLCs in
+// flight' value the remote required is too large to be accepted.
+func ErrMaxHtlcNumTooLarge(maxHtlc, maxMaxHtlc uint16) ReservationError {
+	return ReservationError{
+		fmt.Errorf("maxHtlcs is too large: %d, max is %d",
+			maxHtlc, maxMaxHtlc),
+	}
+}
+
+// ErrMaxHtlcNumTooSmall returns an error indicating that the 'max HTLCs in
+// flight' value the remote required is too small to be accepted.
+func ErrMaxHtlcNumTooSmall(maxHtlc, minMaxHtlc uint16) ReservationError {
+	return ReservationError{
+		fmt.Errorf("maxHtlcs is too small: %d, min is %d",
+			maxHtlc, minMaxHtlc),
+	}
+}
+
+// ErrMaxValueInFlightTooSmall returns an error indicating that the 'max HTLC
+// value in flight' the remote required is too small to be accepted.
+func ErrMaxValueInFlightTooSmall(maxValInFlight,
+	minMaxValInFlight lnwire.MilliSatoshi) ReservationError {
+	return ReservationError{
+		fmt.Errorf("maxValueInFlight too small: %v, min is %v",
+			maxValInFlight, minMaxValInFlight),
+	}
+}

lnwallet/interface_test.go

@@ -581,7 +581,7 @@ func testReservationInitiatorBalanceBelowDustCancel(miner *rpctest.Harness,
 		t.Fatalf("initialization should have failed due to " +
 			"insufficient local amount")
 
-	case !strings.Contains(err.Error(), "local output is too small"):
+	case !strings.Contains(err.Error(), "Funder balance too small"):
 		t.Fatalf("incorrect error: %v", err)
 	}
 }

lnwallet/reservation.go

@@ -1,7 +1,6 @@
 package lnwallet
 
 import (
-	"fmt"
 	"net"
 	"sync"
 
@@ -186,9 +185,11 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount,
 	//
 	// TODO(roasbeef): reject if 30% goes to fees? dust channel
 	if initiator && ourBalance.ToSatoshis() <= 2*DefaultDustLimit() {
-		return nil, fmt.Errorf("unable to init reservation, with "+
+		return nil, ErrFunderBalanceDust(
-			"fee=%v sat/kw, local output is too small: %v sat",
+			int64(commitFee),
-			int64(commitFee), int64(ourBalance.ToSatoshis()))
+			int64(ourBalance.ToSatoshis()),
+			int64(2*DefaultDustLimit()),
+		)
 	}
 
 	// Next we'll set the channel type based on what we can ascertain about
@@ -282,8 +283,9 @@ func (r *ChannelReservation) CommitConstraints(csvDelay, maxHtlcs uint16,
 
 	// Fail if we consider csvDelay excessively large.
 	// TODO(halseth): find a more scientific choice of value.
-	if csvDelay > 10000 {
+	const maxDelay = 10000
-		return fmt.Errorf("csvDelay is too large: %d", csvDelay)
+	if csvDelay > maxDelay {
+		return ErrCsvDelayTooLarge(csvDelay, maxDelay)
 	}
 
 	// Fail if we consider the channel reserve to be too large.
@@ -291,8 +293,7 @@ func (r *ChannelReservation) CommitConstraints(csvDelay, maxHtlcs uint16,
 	// channel capacity.
 	maxChanReserve := r.partialState.Capacity / 5
 	if chanReserve > maxChanReserve {
-		return fmt.Errorf("chanReserve is too large: %g",
+		return ErrChanReserveTooLarge(chanReserve, maxChanReserve)
-			chanReserve.ToBTC())
 	}
 
 	// Fail if the minimum HTLC value is too large. If this is
@@ -302,29 +303,28 @@ func (r *ChannelReservation) CommitConstraints(csvDelay, maxHtlcs uint16,
 	// it wants.
 	// TODO(halseth): set a reasonable/dynamic value.
 	if minHtlc > maxValueInFlight {
-		return fmt.Errorf("minimum HTLC value is too large: %g",
+		return ErrMinHtlcTooLarge(minHtlc, maxValueInFlight)
-			r.ourContribution.MinHTLC.ToBTC())
 	}
 
 	// Fail if maxHtlcs is above the maximum allowed number of 483.
 	// This number is specified in BOLT-02.
 	if maxHtlcs > uint16(MaxHTLCNumber/2) {
-		return fmt.Errorf("maxHtlcs is too large: %d", maxHtlcs)
+		return ErrMaxHtlcNumTooLarge(maxHtlcs, uint16(MaxHTLCNumber/2))
 	}
 
 	// Fail if we consider maxHtlcs too small. If this is too small
 	// we cannot offer many HTLCs to the remote.
 	const minNumHtlc = 5
 	if maxHtlcs < minNumHtlc {
-		return fmt.Errorf("maxHtlcs is too small: %d", maxHtlcs)
+		return ErrMaxHtlcNumTooSmall(maxHtlcs, minNumHtlc)
 	}
 
 	// Fail if we consider maxValueInFlight too small. We currently
 	// require the remote to at least allow minNumHtlc * minHtlc
 	// in flight.
 	if maxValueInFlight < minNumHtlc*minHtlc {
-		return fmt.Errorf("maxValueInFlight is too small: %g",
+		return ErrMaxValueInFlightTooSmall(maxValueInFlight,
-			maxValueInFlight.ToBTC())
+			minNumHtlc*minHtlc)
 	}
 
 	r.ourContribution.ChannelConfig.CsvDelay = csvDelay

lnwallet/wallet.go

@@ -479,8 +479,8 @@ func (l *LightningWallet) InitChannelReservation(
 func (l *LightningWallet) handleFundingReserveRequest(req *initFundingReserveMsg) {
 	// It isn't possible to create a channel with zero funds committed.
 	if req.fundingAmount+req.capacity == 0 {
-		req.err <- fmt.Errorf("cannot have channel with zero " +
+		err := ErrZeroCapacity()
-			"satoshis funded")
+		req.err <- err
 		req.resp <- nil
 		return
 	}
@@ -488,9 +488,9 @@ func (l *LightningWallet) handleFundingReserveRequest(req *initFundingReserveMsg
 	// If the funding request is for a different chain than the one the
 	// wallet is aware of, then we'll reject the request.
 	if !bytes.Equal(l.Cfg.NetParams.GenesisHash[:], req.chainHash[:]) {
-		req.err <- fmt.Errorf("unable to create channel reservation "+
+		err := ErrChainMismatch(l.Cfg.NetParams.GenesisHash,
-			"for chain=%v, wallet is on chain=%v",
+			req.chainHash)
-			req.chainHash, l.Cfg.NetParams.GenesisHash)
+		req.err <- err
 		req.resp <- nil
 		return
 	}

lnwire/error.go

@@ -48,6 +48,13 @@ func (e ErrorCode) String() string {
 	}
 }
 
+// Error returns the human redable version of the target ErrorCode.
+//
+// Satisfies the Error interface.
+func (e ErrorCode) Error() string {
+	return e.String()
+}
+
 // ErrorData is a set of bytes associated with a particular sent error. A
 // receiving node SHOULD only print out data verbatim if the string is composed
 // solely of printable ASCII characters. For reference, the printable character