Add support for deserializing the new SCID alias in funding_locked

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -3457,6 +3457,7 @@ impl<Signer: Sign> Channel<Signer> {
 			Some(msgs::FundingLocked {
 				channel_id: self.channel_id(),
 				next_per_commitment_point,
+				short_channel_id_alias: None,
 			})
 		} else { None };
 
@@ -3678,6 +3679,7 @@ impl<Signer: Sign> Channel<Signer> {
 				funding_locked: Some(msgs::FundingLocked {
 					channel_id: self.channel_id(),
 					next_per_commitment_point,
+					short_channel_id_alias: None,
 				}),
 				raa: None, commitment_update: None, mon_update: None,
 				order: RAACommitmentOrder::CommitmentFirst,
@@ -3713,6 +3715,7 @@ impl<Signer: Sign> Channel<Signer> {
 			Some(msgs::FundingLocked {
 				channel_id: self.channel_id(),
 				next_per_commitment_point,
+				short_channel_id_alias: None,
 			})
 		} else { None };
 
@@ -4447,6 +4450,7 @@ impl<Signer: Sign> Channel<Signer> {
 					return Some(msgs::FundingLocked {
 						channel_id: self.channel_id,
 						next_per_commitment_point,
+						short_channel_id_alias: None,
 					});
 				}
 			} else {

lightning/src/ln/msgs.rs

@@ -241,6 +241,9 @@ pub struct FundingLocked {
 	pub channel_id: [u8; 32],
 	/// The per-commitment point of the second commitment transaction
 	pub next_per_commitment_point: PublicKey,
+	/// If set, provides a short_channel_id alias for this channel. The sender will accept payments
+	/// to be forwarded over this SCID and forward them to this messages' recipient.
+	pub short_channel_id_alias: Option<u64>,
 }
 
 /// A shutdown message to be sent or received from a peer
@@ -1155,7 +1158,9 @@ impl_writeable_msg!(FundingSigned, {
 impl_writeable_msg!(FundingLocked, {
 	channel_id,
 	next_per_commitment_point,
-}, {});
+}, {
+	(1, short_channel_id_alias, option),
+});
 
 impl Writeable for Init {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
@@ -2246,6 +2251,7 @@ mod tests {
 		let funding_locked = msgs::FundingLocked {
 			channel_id: [2; 32],
 			next_per_commitment_point: pubkey_1,
+			short_channel_id_alias: None,
 		};
 		let encoded_value = funding_locked.encode();
 		let target_value = hex::decode("0202020202020202020202020202020202020202020202020202020202020202031b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f").unwrap();