lnwire: add new QueryChannelRange gossip query message

lnwire/query_channel_range.go

@@ -0,0 +1,77 @@
+package lnwire
+
+import (
+	"io"
+
+	"github.com/roasbeef/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
+}