lnwire: add a ChannelAnnouncement interface

Add a new ChannelAnnouncement interface and ensure that
ChannelAnnouncement1 implements it.

lnwire/channel_announcement.go

@@ -190,6 +190,8 @@ func (a *ChannelAnnouncement1) DataToSign() ([]byte, error) {
 // Validate validates the channel announcement message and checks that node
 // signatures covers the announcement message, and that the bitcoin signatures
 // covers the node keys.
+//
+// NOTE: This is part of the ChannelAnnouncement interface.
 func (a *ChannelAnnouncement1) Validate(_ func(id *ShortChannelID) (
 	[]byte, error)) error {
 
@@ -260,3 +262,38 @@ func (a *ChannelAnnouncement1) Validate(_ func(id *ShortChannelID) (
 
 	return nil
 }
+
+// Node1KeyBytes returns the bytes representing the public key of node 1 in the
+// channel.
+//
+// NOTE: This is part of the ChannelAnnouncement interface.
+func (a *ChannelAnnouncement1) Node1KeyBytes() [33]byte {
+	return a.NodeID1
+}
+
+// Node2KeyBytes returns the bytes representing the public key of node 2 in the
+// channel.
+//
+// NOTE: This is part of the ChannelAnnouncement interface.
+func (a *ChannelAnnouncement1) Node2KeyBytes() [33]byte {
+	return a.NodeID2
+}
+
+// GetChainHash returns the hash of the chain which this channel's funding
+// transaction is confirmed in.
+//
+// NOTE: This is part of the ChannelAnnouncement interface.
+func (a *ChannelAnnouncement1) GetChainHash() chainhash.Hash {
+	return a.ChainHash
+}
+
+// SCID returns the short channel ID of the channel.
+//
+// NOTE: This is part of the ChannelAnnouncement interface.
+func (a *ChannelAnnouncement1) SCID() ShortChannelID {
+	return a.ShortChannelID
+}
+
+// A compile-time check to ensure that ChannelAnnouncement1 implements the
+// ChannelAnnouncement interface.
+var _ ChannelAnnouncement = (*ChannelAnnouncement1)(nil)

lnwire/interfaces.go

@@ -1,5 +1,7 @@
 package lnwire
 
+import "github.com/btcsuite/btcd/chaincfg/chainhash"
+
 // AnnounceSignatures is an interface that represents a message used to
 // exchange signatures of a ChannelAnnouncment message during the funding flow.
 type AnnounceSignatures interface {
@@ -11,3 +13,27 @@ type AnnounceSignatures interface {
 
 	Message
 }
+
+// ChannelAnnouncement is an interface that must be satisfied by any message
+// used to announce and prove the existence of a channel.
+type ChannelAnnouncement interface {
+	// SCID returns the short channel ID of the channel.
+	SCID() ShortChannelID
+
+	// GetChainHash returns the hash of the chain which this channel's
+	// funding transaction is confirmed in.
+	GetChainHash() chainhash.Hash
+
+	// Node1KeyBytes returns the bytes representing the public key of node
+	// 1 in the channel.
+	Node1KeyBytes() [33]byte
+
+	// Node2KeyBytes returns the bytes representing the public key of node
+	// 2 in the channel.
+	Node2KeyBytes() [33]byte
+
+	// Validate checks the various signatures of the announcement.
+	Validate(fetchPKScript func(id *ShortChannelID) ([]byte, error)) error
+
+	Message
+}