lnd.xprv/lnwire/channel_update.go

153 lines
3.8 KiB
Go

package lnwire
import (
"bytes"
"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 uint64
// BaseFee is the base fee that must be used for incoming HTLC's to
// this particular channel. This value will be tacked onto the required
// for a payment independent of the size of the payment.
BaseFee uint32
// FeeRate is the fee rate that will be charged per millionth of a
// satoshi.
FeeRate uint32
}
// A compile time check to ensure ChannelUpdate implements the lnwire.Message
// interface.
var _ Message = (*ChannelUpdate)(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.BaseFee,
&a.FeeRate,
)
}
// 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.BaseFee,
a.FeeRate,
)
}
// MsgType returns the integer uniquely identifying this message type on the
// wire.
//
// This is part of the lnwire.Message interface.
func (a *ChannelUpdate) MsgType() MessageType {
return MsgChannelUpdate
}
// 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 - 8 bytes
length += 8
// 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.BaseFee,
a.FeeRate,
)
if err != nil {
return nil, err
}
return w.Bytes(), nil
}