153 lines
3.8 KiB
Go
153 lines
3.8 KiB
Go
package lnwire
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import (
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"bytes"
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"io"
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"github.com/roasbeef/btcd/btcec"
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)
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// ChannelUpdate message is used after channel has been initially announced.
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// Each side independently announces its fees and minimum expiry for HTLCs and
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// other parameters. Also this message is used to redeclare initially setted
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// channel parameters.
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type ChannelUpdate struct {
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// Signature is used to validate the announced data and prove the
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// ownership of node id.
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Signature *btcec.Signature
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// ShortChannelID is the unique description of the funding transaction.
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ShortChannelID ShortChannelID
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// Timestamp allows ordering in the case of multiple announcements.
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// We should ignore the message if timestamp is not greater than
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// the last-received.
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Timestamp uint32
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// Flags least-significant bit must be set to 0 if the creating node
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// corresponds to the first node in the previously sent channel
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// announcement and 1 otherwise.
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Flags uint16
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// TimeLockDelta is the minimum number of blocks this node requires to
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// be added to the expiry of HTLCs. This is a security parameter
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// determined by the node operator. This value represents the required
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// gap between the time locks of the incoming and outgoing HTLC's set
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// to this node.
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TimeLockDelta uint16
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// HtlcMinimumMsat is the minimum HTLC value which will be accepted.
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HtlcMinimumMsat uint64
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// BaseFee is the base fee that must be used for incoming HTLC's to
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// this particular channel. This value will be tacked onto the required
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// for a payment independent of the size of the payment.
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BaseFee uint32
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// FeeRate is the fee rate that will be charged per millionth of a
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// satoshi.
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FeeRate uint32
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}
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// A compile time check to ensure ChannelUpdate implements the lnwire.Message
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// interface.
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var _ Message = (*ChannelUpdate)(nil)
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// Decode deserializes a serialized ChannelUpdate stored in the passed
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// io.Reader observing the specified protocol version.
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//
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// This is part of the lnwire.Message interface.
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func (a *ChannelUpdate) Decode(r io.Reader, pver uint32) error {
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return readElements(r,
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&a.Signature,
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&a.ShortChannelID,
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&a.Timestamp,
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&a.Flags,
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&a.TimeLockDelta,
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&a.HtlcMinimumMsat,
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&a.BaseFee,
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&a.FeeRate,
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)
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}
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// Encode serializes the target ChannelUpdate into the passed io.Writer
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// observing the protocol version specified.
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//
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// This is part of the lnwire.Message interface.
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func (a *ChannelUpdate) Encode(w io.Writer, pver uint32) error {
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return writeElements(w,
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a.Signature,
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a.ShortChannelID,
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a.Timestamp,
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a.Flags,
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a.TimeLockDelta,
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a.HtlcMinimumMsat,
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a.BaseFee,
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a.FeeRate,
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)
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}
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// MsgType returns the integer uniquely identifying this message type on the
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// wire.
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//
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// This is part of the lnwire.Message interface.
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func (a *ChannelUpdate) MsgType() MessageType {
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return MsgChannelUpdate
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}
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// MaxPayloadLength returns the maximum allowed payload size for this message
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// observing the specified protocol version.
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//
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// This is part of the lnwire.Message interface.
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func (a *ChannelUpdate) MaxPayloadLength(pver uint32) uint32 {
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var length uint32
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// Signature - 64 bytes
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length += 64
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// ShortChannelID - 8 bytes
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length += 8
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// Timestamp - 4 bytes
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length += 4
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// Flags - 2 bytes
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length += 2
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// Expiry - 2 bytes
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length += 2
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// HtlcMinimumMstat - 8 bytes
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length += 8
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// FeeBaseMstat - 4 bytes
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length += 4
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// FeeProportionalMillionths - 4 bytes
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length += 4
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return length
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}
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// DataToSign is used to retrieve part of the announcement message which should
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// be signed.
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func (a *ChannelUpdate) DataToSign() ([]byte, error) {
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// We should not include the signatures itself.
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var w bytes.Buffer
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err := writeElements(&w,
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a.ShortChannelID,
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a.Timestamp,
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a.Flags,
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a.TimeLockDelta,
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a.HtlcMinimumMsat,
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a.BaseFee,
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a.FeeRate,
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)
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if err != nil {
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return nil, err
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}
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return w.Bytes(), nil
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}
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