Implement ZeroConf channel type.

Author: tnull

lightning/src/ln/channelmanager.rs

@@ -4200,7 +4200,11 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 				if *counterparty_node_id != channel.get().get_counterparty_node_id() {
 					return Err(APIError::APIMisuseError { err: "The passed counterparty_node_id doesn't match the channel's counterparty node_id".to_owned() });
 				}
-				if accept_0conf { channel.get_mut().set_0conf(); }
+				if accept_0conf {
+					channel.get_mut().set_0conf();
+				} else if channel.get().get_channel_type().requires_zero_conf() {
+					return Err(APIError::APIMisuseError { err: "This channel requires 0conf. Please use accept_inbound_channel_from_trusted_peer_0conf to accept.".to_owned() });
+				}
 				channel_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
 					node_id: channel.get().get_counterparty_node_id(),
 					msg: channel.get_mut().accept_inbound_channel(user_channel_id),
@@ -4242,6 +4246,9 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 			},
 			hash_map::Entry::Vacant(entry) => {
 				if !self.default_configuration.manually_accept_inbound_channels {
+					if channel.get_channel_type().requires_zero_conf() {
+						return Err(MsgHandleErrInternal::send_err_msg_no_close("No zero confirmation channels accepted".to_owned(), msg.temporary_channel_id.clone()));
+					}
 					channel_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
 						node_id: counterparty_node_id.clone(),
 						msg: channel.accept_inbound_channel(0),

lightning/src/ln/features.rs

@@ -217,7 +217,7 @@ mod sealed {
 			// Byte 4
 			,
 			// Byte 5
-			SCIDPrivacy,
+			SCIDPrivacy | ZeroConf,
 		],
 		optional_features: [
 			// Byte 0
@@ -402,7 +402,9 @@ mod sealed {
 	define_feature!(47, SCIDPrivacy, [InitContext, NodeContext, ChannelTypeContext],
 		"Feature flags for only forwarding with SCID aliasing. Called `option_scid_alias` in the BOLTs",
 		set_scid_privacy_optional, set_scid_privacy_required, supports_scid_privacy, requires_scid_privacy);
-
+	define_feature!(51, ZeroConf, [ChannelTypeContext],
+		"Feature flags for accepting channels with zero confirmations. Called `option_zeroconf` in the BOLTs",
+		set_zero_conf_optional, set_zero_conf_required, supports_zero_conf, requires_zero_conf);
 	define_feature!(55, Keysend, [NodeContext],
 		"Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
 		supports_keysend, requires_keysend);

lightning/src/util/events.rs

@@ -466,6 +466,10 @@ pub enum Event {
 		/// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
 		/// 0.0.106.
 		///
+		/// Also note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
+		/// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
+		/// 0.0.107.
+		///
 		/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 		channel_type: ChannelTypeFeatures,
 	},