lnd.xprv/lnwire/query_channel_range.go

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package lnwire
import (
"io"
"math"
"github.com/btcsuite/btcd/chaincfg/chainhash"
)
// QueryChannelRange is a message sent by a node in order to query the
// receiving node of the set of open channel they know of with short channel
// ID's after the specified block height, capped at the number of blocks beyond
// that block height. This will be used by nodes upon initial connect to
// synchronize their views of the network.
type QueryChannelRange struct {
// ChainHash denotes the target chain that we're trying to synchronize
// channel graph state for.
ChainHash chainhash.Hash
// FirstBlockHeight is the first block in the query range. The
// responder should send all new short channel IDs from this block
// until this block plus the specified number of blocks.
FirstBlockHeight uint32
// NumBlocks is the number of blocks beyond the first block that short
// channel ID's should be sent for.
NumBlocks uint32
}
// NewQueryChannelRange creates a new empty QueryChannelRange message.
func NewQueryChannelRange() *QueryChannelRange {
return &QueryChannelRange{}
}
// A compile time check to ensure QueryChannelRange implements the
// lnwire.Message interface.
var _ Message = (*QueryChannelRange)(nil)
// Decode deserializes a serialized QueryChannelRange message stored in the
// passed io.Reader observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (q *QueryChannelRange) Decode(r io.Reader, pver uint32) error {
return ReadElements(r,
q.ChainHash[:],
&q.FirstBlockHeight,
&q.NumBlocks,
)
}
// Encode serializes the target QueryChannelRange into the passed io.Writer
// observing the protocol version specified.
//
// This is part of the lnwire.Message interface.
func (q *QueryChannelRange) Encode(w io.Writer, pver uint32) error {
return WriteElements(w,
q.ChainHash[:],
q.FirstBlockHeight,
q.NumBlocks,
)
}
// MsgType returns the integer uniquely identifying this message type on the
// wire.
//
// This is part of the lnwire.Message interface.
func (q *QueryChannelRange) MsgType() MessageType {
return MsgQueryChannelRange
}
// MaxPayloadLength returns the maximum allowed payload size for a
// QueryChannelRange complete message observing the specified protocol version.
//
// This is part of the lnwire.Message interface.
func (q *QueryChannelRange) MaxPayloadLength(uint32) uint32 {
// 32 + 4 + 4
return 40
}
// LastBlockHeight returns the last block height covered by the range of a
// QueryChannelRange message.
func (q *QueryChannelRange) LastBlockHeight() uint32 {
// Handle overflows by casting to uint64.
lastBlockHeight := uint64(q.FirstBlockHeight) + uint64(q.NumBlocks) - 1
if lastBlockHeight > math.MaxUint32 {
return math.MaxUint32
}
return uint32(lastBlockHeight)
}