lnwire: convert ErrorGeneric to Error

With this change we move one step closer to matching the wire protocol
currently defined within the spec.

lnwire/error.go

@@ -0,0 +1,123 @@
+package lnwire
+
+import (
+	"fmt"
+	"io"
+	"math"
+
+	"google.golang.org/grpc/codes"
+)
+
+// ErrorCode represents the short error code for each of the defined errors
+// within the Lightning Network protocol spec.
+type ErrorCode uint16
+
+// ToGrpcCode is used to generate gRPC specific code which will be propagated
+// to the ln rpc client. This code is used to have more detailed view of what
+// goes wrong and also in order to have the ability pragmatically determine
+// the error and take specific actions on the client side.
+func (e ErrorCode) ToGrpcCode() codes.Code {
+	return (codes.Code)(e) + 100
+}
+
+const (
+	// ErrMaxPendingChannels is returned by remote peer when the number of
+	// active pending channels exceeds their maximum policy limit.
+	ErrMaxPendingChannels ErrorCode = 1
+
+	// ErrSynchronizingChain is returned by a remote peer that receives a
+	// channel update or a funding request while their still syncing to the
+	// latest state of the blockchain.
+	ErrSynchronizingChain ErrorCode = 2
+)
+
+// 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
+// set includes byte values 32 through 127 inclusive.
+type ErrorData []byte
+
+// Error represents a generic error bound to an exact channel. The message
+// format is purposefully general in order to allow expression of a wide array
+// of possible errors. Each Error message is directed at a particular open
+// channel referenced by ChannelPoint.
+type Error struct {
+	// ChanID references the active channel in which the error occurred
+	// within. If the ChanID is all zeroes, then this error applies to the
+	// entire established connection.
+	ChanID ChannelID
+
+	// Code is the short error code that succinctly identifies the error
+	// code. This is similar field is similar to HTTP error codes.
+	//
+	// TODO(roasbeef): make PR to repo to add error codes, in addition to
+	// what's there atm
+	Code ErrorCode
+
+	// Data is the attached error data that describes the exact failure
+	// which caused the error message to be sent.
+	Data ErrorData
+}
+
+// NewError creates a new Error message.
+func NewError() *Error {
+	return &Error{}
+}
+
+// A compile time check to ensure Error implements the lnwire.Message
+// interface.
+var _ Message = (*Error)(nil)
+
+// Decode deserializes a serialized Error message stored in the passed
+// io.Reader observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (c *Error) Decode(r io.Reader, pver uint32) error {
+	return readElements(r,
+		&c.ChanID,
+		&c.Code,
+		&c.Data,
+	)
+}
+
+// Encode serializes the target Error into the passed io.Writer observing the
+// protocol version specified.
+//
+// This is part of the lnwire.Message interface.
+func (c *Error) Encode(w io.Writer, pver uint32) error {
+	return writeElements(w,
+		c.ChanID,
+		c.Code,
+		c.Data,
+	)
+}
+
+// Command returns the integer uniquely identifying an Error message on the
+// wire.
+//
+// This is part of the lnwire.Message interface.
+func (c *Error) Command() uint32 {
+	return CmdError
+}
+
+// MaxPayloadLength returns the maximum allowed payload size for a Error
+// complete message observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (c *Error) MaxPayloadLength(uint32) uint32 {
+	// 32 + 2 + 655326
+	return 65536
+}
+
+// Validate performs any necessary sanity checks to ensure all fields present
+// on the Error are valid.
+//
+// This is part of the lnwire.Message interface.
+func (c *Error) Validate() error {
+	if len(c.Data) > math.MaxUint16 {
+		return fmt.Errorf("problem string length too long")
+	}
+
+	// We're good!
+	return nil
+}

lnwire/error_generic.go

@@ -1,125 +0,0 @@
-package lnwire
-
-import (
-	"fmt"
-	"io"
-
-	"github.com/roasbeef/btcd/wire"
-	"google.golang.org/grpc/codes"
-)
-
-// ErrorCode represents the short error code for each of the defined errors
-// within the Lightning Network protocol spec.
-type ErrorCode uint16
-
-// ToGrpcCode is used to generate gRPC specific code which will be propagated
-// to the ln rpc client. This code is used to have more detailed view of what
-// goes wrong and also in order to have the ability pragmatically determine
-// the error and take specific actions on the client side.
-func (e ErrorCode) ToGrpcCode() codes.Code {
-	return (codes.Code)(e) + 100
-}
-
-const (
-	// ErrMaxPendingChannels is returned by remote peer when the number of
-	// active pending channels exceeds their maximum policy limit.
-	ErrMaxPendingChannels ErrorCode = 1
-
-	// ErrSynchronizingChain is returned by a remote peer that receives a
-	// channel update or a funding request while their still syncing to the
-	// latest state of the blockchain.
-	ErrSynchronizingChain ErrorCode = 2
-)
-
-// ErrorGeneric represents a generic error bound to an exact channel. The
-// message format is purposefully general in order to allow expression of a wide
-// array of possible errors. Each ErrorGeneric message is directed at a particular
-// open channel referenced by ChannelPoint.
-type ErrorGeneric struct {
-	// ChannelPoint references the active channel in which the error
-	// occurred within. A ChannelPoint of zeroHash:0 denotes this error
-	// applies to the entire established connection.
-	ChannelPoint wire.OutPoint
-
-	// PendingChannelID allows peers communicate errors in the context of a
-	// particular pending channel. With this field, once a peer reads an
-	// ErrorGeneric message with the PendingChannelID field set, then they
-	// can forward the error to the fundingManager who can handle it
-	// properly.
-	PendingChannelID uint64
-
-	// Code is the short error ID which describes the nature of the error.
-	Code ErrorCode
-
-	// Problem is a human-readable string further elaborating upon the
-	// nature of the exact error. The maximum allowed length of this
-	// message is 8192 bytes.
-	Problem string
-}
-
-// NewErrorGeneric creates a new ErrorGeneric message.
-func NewErrorGeneric() *ErrorGeneric {
-	return &ErrorGeneric{}
-}
-
-// A compile time check to ensure ErrorGeneric implements the lnwire.Message
-// interface.
-var _ Message = (*ErrorGeneric)(nil)
-
-// Decode deserializes a serialized ErrorGeneric message stored in the
-// passed io.Reader observing the specified protocol version.
-//
-// This is part of the lnwire.Message interface.
-func (c *ErrorGeneric) Decode(r io.Reader, pver uint32) error {
-	// ChannelPoint(8)
-	// Problem
-	return readElements(r,
-		&c.ChannelPoint,
-		&c.Code,
-		&c.Problem,
-		&c.PendingChannelID,
-	)
-}
-
-// Encode serializes the target ErrorGeneric into the passed io.Writer
-// observing the protocol version specified.
-//
-// This is part of the lnwire.Message interface.
-func (c *ErrorGeneric) Encode(w io.Writer, pver uint32) error {
-	return writeElements(w,
-		c.ChannelPoint,
-		c.Code,
-		c.Problem,
-		c.PendingChannelID,
-	)
-}
-
-// Command returns the integer uniquely identifying an ErrorGeneric message on
-// the wire.
-//
-// This is part of the lnwire.Message interface.
-func (c *ErrorGeneric) Command() uint32 {
-	return CmdErrorGeneric
-}
-
-// MaxPayloadLength returns the maximum allowed payload size for a
-// ErrorGeneric complete message observing the specified protocol version.
-//
-// This is part of the lnwire.Message interface.
-func (c *ErrorGeneric) MaxPayloadLength(uint32) uint32 {
-	// 8+8192
-	return 8208
-}
-
-// Validate performs any necessary sanity checks to ensure all fields present
-// on the ErrorGeneric are valid.
-//
-// This is part of the lnwire.Message interface.
-func (c *ErrorGeneric) Validate() error {
-	if len(c.Problem) > 8192 {
-		return fmt.Errorf("problem string length too long")
-	}
-
-	// We're good!
-	return nil
-}

lnwire/error_test.go

@@ -6,22 +6,21 @@ import (
 	"testing"
 )
 
-func TestErrorGenericEncodeDecode(t *testing.T) {
+func TestErrorEncodeDecode(t *testing.T) {
-	eg := &ErrorGeneric{
+	eg := &Error{
-		ChannelPoint:     *outpoint1,
+		ChanID: ChannelID(revHash),
-		PendingChannelID: 1,
 		Code:   99,
-		Problem:          "Hello world!",
+		Data:   []byte{'k', 'e', 'k'},
 	}
 
-	// Next encode the EG message into an empty bytes buffer.
+	// Next encode the error message into an empty bytes buffer.
 	var b bytes.Buffer
 	if err := eg.Encode(&b, 0); err != nil {
 		t.Fatalf("unable to encode ErrorGeneric: %v", err)
 	}
 
-	// Deserialize the encoded EG message into a new empty struct.
+	// Deserialize the encoded error message into a new empty struct.
-	eg2 := &ErrorGeneric{}
+	eg2 := &Error{}
 	if err := eg2.Decode(&b, 0); err != nil {
 		t.Fatalf("unable to decode ErrorGeneric: %v", err)
 	}

lnwire/lnwire.go

@@ -174,6 +174,16 @@ func writeElement(w io.Writer, element interface{}) error {
 		if _, err := w.Write(b[:]); err != nil {
 			return err
 		}
+	case ErrorData:
+		var l [2]byte
+		binary.BigEndian.PutUint16(l[:], uint16(len(e)))
+		if _, err := w.Write(l[:]); err != nil {
+			return err
+		}
+
+		if _, err := w.Write(e[:]); err != nil {
+			return err
+		}
 	case OpaqueReason:
 		var l [2]byte
 		binary.BigEndian.PutUint16(l[:], uint16(len(e)))
@@ -514,6 +524,17 @@ func readElement(r io.Reader, element interface{}) error {
 		if _, err := io.ReadFull(r, *e); err != nil {
 			return err
 		}
+	case *ErrorData:
+		var l [2]byte
+		if _, err := io.ReadFull(r, l[:]); err != nil {
+			return err
+		}
+		errorLen := binary.BigEndian.Uint16(l[:])
+
+		*e = ErrorData(make([]byte, errorLen))
+		if _, err := io.ReadFull(r, *e); err != nil {
+			return err
+		}
 	case *[6]byte:
 		if _, err := io.ReadFull(r, e[:]); err != nil {
 			return err

lnwire/message.go

@@ -49,7 +49,7 @@ const (
 	CmdRevokeAndAck = uint32(2010)
 
 	// Commands for reporting protocol errors.
-	CmdErrorGeneric = uint32(4000)
+	CmdError = uint32(4000)
 
 	// Commands for discovery service.
 	CmdChannelAnnouncement       = uint32(5000)
@@ -119,8 +119,8 @@ func makeEmptyMessage(command uint32) (Message, error) {
 		msg = &CommitSig{}
 	case CmdRevokeAndAck:
 		msg = &RevokeAndAck{}
-	case CmdErrorGeneric:
+	case CmdError:
-		msg = &ErrorGeneric{}
+		msg = &Error{}
 	case CmdChannelAnnouncement:
 		msg = &ChannelAnnouncement{}
 	case CmdChannelUpdateAnnouncement: