lnwire: rename ChannelUpdateAnnouncement to ChannelUpdate

lnwire/channel_update.go

@@ -0,0 +1,166 @@
+package lnwire
+
+import (
+	"bytes"
+	"errors"
+	"io"
+
+	"github.com/roasbeef/btcd/btcec"
+)
+
+// ChannelUpdate message is used after channel has been initially announced.
+// Each side independently announces its fees and minimum expiry for HTLCs and
+// other parameters. Also this message is used to redeclare initially setted
+// channel parameters.
+type ChannelUpdate struct {
+	// Signature is used to validate the announced data and prove the
+	// ownership of node id.
+	Signature *btcec.Signature
+
+	// ShortChannelID is the unique description of the funding transaction.
+	ShortChannelID ShortChannelID
+
+	// Timestamp allows ordering in the case of multiple announcements.
+	// We should ignore the message if timestamp is not greater than
+	// the last-received.
+	Timestamp uint32
+
+	// Flags least-significant bit must be set to 0 if the creating node
+	// corresponds to the first node in the previously sent channel
+	// announcement and 1 otherwise.
+	Flags uint16
+
+	// TimeLockDelta is the minimum number of blocks this node requires to
+	// be added to the expiry of HTLCs. This is a security parameter
+	// determined by the node operator. This value represents the required
+	// gap between the time locks of the incoming and outgoing HTLC's set
+	// to this node.
+	TimeLockDelta uint16
+
+	// HtlcMinimumMsat is the minimum HTLC value which will be accepted.
+	HtlcMinimumMsat uint32
+
+	// FeeBaseMstat...
+	FeeBaseMsat uint32
+
+	// FeeProportionalMillionths...
+	FeeProportionalMillionths uint32
+}
+
+// A compile time check to ensure ChannelUpdate implements the lnwire.Message
+// interface.
+var _ Message = (*ChannelUpdate)(nil)
+
+// Validate performs any necessary sanity checks to ensure all fields present
+// on the ChannelUpdate are valid.
+//
+// This is part of the lnwire.Message interface.
+func (a *ChannelUpdate) Validate() error {
+	// NOTE: As far as we don't have the node id (public key) in this
+	// message, we can't validate the signature on this stage, it should
+	// be validated latter - in discovery service handler.
+
+	if a.TimeLockDelta == 0 {
+		return errors.New("expiry should be greater then zero")
+	}
+
+	return nil
+}
+
+// Decode deserializes a serialized ChannelUpdate stored in the passed
+// io.Reader observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (a *ChannelUpdate) Decode(r io.Reader, pver uint32) error {
+	return readElements(r,
+		&a.Signature,
+		&a.ShortChannelID,
+		&a.Timestamp,
+		&a.Flags,
+		&a.TimeLockDelta,
+		&a.HtlcMinimumMsat,
+		&a.FeeBaseMsat,
+		&a.FeeProportionalMillionths,
+	)
+}
+
+// Encode serializes the target ChannelUpdate into the passed io.Writer
+// observing the protocol version specified.
+//
+// This is part of the lnwire.Message interface.
+func (a *ChannelUpdate) Encode(w io.Writer, pver uint32) error {
+	return writeElements(w,
+		a.Signature,
+		a.ShortChannelID,
+		a.Timestamp,
+		a.Flags,
+		a.TimeLockDelta,
+		a.HtlcMinimumMsat,
+		a.FeeBaseMsat,
+		a.FeeProportionalMillionths,
+	)
+}
+
+// Command returns the integer uniquely identifying this message type on the
+// wire.
+//
+// This is part of the lnwire.Message interface.
+func (a *ChannelUpdate) Command() uint32 {
+	return CmdChannelUpdate
+}
+
+// MaxPayloadLength returns the maximum allowed payload size for this message
+// observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (a *ChannelUpdate) MaxPayloadLength(pver uint32) uint32 {
+	var length uint32
+
+	// Signature - 64 bytes
+	length += 64
+
+	// ShortChannelID - 8 bytes
+	length += 8
+
+	// Timestamp - 4 bytes
+	length += 4
+
+	// Flags - 2 bytes
+	length += 2
+
+	// Expiry - 2 bytes
+	length += 2
+
+	// HtlcMinimumMstat - 4 bytes
+	length += 4
+
+	// FeeBaseMstat - 4 bytes
+	length += 4
+
+	// FeeProportionalMillionths - 4 bytes
+	length += 4
+
+	return length
+}
+
+// DataToSign is used to retrieve part of the announcement message which should
+// be signed.
+func (a *ChannelUpdate) DataToSign() ([]byte, error) {
+
+	// We should not include the signatures itself.
+	var w bytes.Buffer
+	err := writeElements(&w,
+		a.ShortChannelID,
+		a.Timestamp,
+		a.Flags,
+		a.TimeLockDelta,
+		a.HtlcMinimumMsat,
+		a.FeeBaseMsat,
+		a.FeeProportionalMillionths,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return w.Bytes(), nil
+}