Split generating AcceptChannel msgs and the accept

Author: ViktorT-11

lightning/src/ln/channel.rs

@@ -536,15 +536,15 @@ pub(super) struct Channel<Signer: Sign> {
 	#[cfg(not(test))]
 	closing_fee_limits: Option<(u64, u64)>,
 
-	/// Flag that ensures that the `get_accept_channel` function must be called before the
+	/// Flag that ensures that the `accept_inbound_channel` function must be called before the
 	/// `funding_created` function is executed successfully. The reason for this flag is that
 	/// when the util::config::UserConfig.manually_accept_inbound_channels is set to true,
 	/// inbound channels are required to be manually accepted by the node operator before the
-	/// `SendAcceptChannel` message is created and sent out. The `get_accept_channel` function is
+	/// `SendAcceptChannel` message is created and sent out. The `accept_inbound_channel` function is
 	/// called during that process.
 	/// A counterparty node could theoretically send a `FundingCreated` message before the node
 	/// operator has accepted the inbound channel. That would would execute the `funding_created`
-	/// function before the `get_accept_channel` function, and should therefore be rejected.
+	/// function before the `accept_inbound_channel` function, and should therefore be rejected.
 	inbound_awaiting_accept: bool,
 
 	/// The hash of the block in which the funding transaction was included.
@@ -4526,7 +4526,11 @@ impl<Signer: Sign> Channel<Signer> {
 		self.inbound_awaiting_accept
 	}
 
-	pub fn get_accept_channel(&mut self) -> msgs::AcceptChannel {
+	/// Marks an inbound channel as accepted and generates a [`msgs::AcceptChannel`] message which
+	/// should be sent back to the counterparty node.
+	///
+	/// [`msgs::AcceptChannel`]: crate::ln::msgs::AcceptChannel
+	pub fn accept_inbound_channel(&mut self) -> msgs::AcceptChannel {
 		if self.is_outbound() {
 			panic!("Tried to send accept_channel for an outbound channel?");
 		}
@@ -4536,9 +4540,21 @@ impl<Signer: Sign> Channel<Signer> {
 		if self.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
 			panic!("Tried to send an accept_channel for a channel that has already advanced");
 		}
+		if !self.inbound_awaiting_accept {
+			panic!("The inbound channel has already been accepted");
+		}
 
 		self.inbound_awaiting_accept = false;
 
+		return self.get_accept_channel_message();
+	}
+
+	/// This function is used to explicitly generate a [`msgs::AcceptChannel`] message for an
+	/// inbound channel. If the intention is to accept an inbound channel, you should use the
+	/// [`Channel::accept_inbound_channel`] function instead.
+	///
+	/// [`msgs::AcceptChannel`]: crate::ln::msgs::AcceptChannel
+	pub fn get_accept_channel_message(&self) -> msgs::AcceptChannel {
 		let first_per_commitment_point = self.holder_signer.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
 		let keys = self.get_holder_pubkeys();
 
@@ -6079,7 +6095,7 @@ mod tests {
 		let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), &open_channel_msg, 7, &config, 0, &&logger).unwrap();
 
 		// Node B --> Node A: accept channel, explicitly setting B's dust limit.
-		let mut accept_channel_msg = node_b_chan.get_accept_channel();
+		let mut accept_channel_msg = node_b_chan.accept_inbound_channel();
 		accept_channel_msg.dust_limit_satoshis = 546;
 		node_a_chan.accept_channel(&accept_channel_msg, &config, &InitFeatures::known()).unwrap();
 		node_a_chan.holder_dust_limit_satoshis = 1560;
@@ -6197,7 +6213,7 @@ mod tests {
 		let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), &open_channel_msg, 7, &config, 0, &&logger).unwrap();
 
 		// Node B --> Node A: accept channel
-		let accept_channel_msg = node_b_chan.get_accept_channel();
+		let accept_channel_msg = node_b_chan.accept_inbound_channel();
 		node_a_chan.accept_channel(&accept_channel_msg, &config, &InitFeatures::known()).unwrap();
 
 		// Node A --> Node B: funding created

lightning/src/ln/channelmanager.rs

@@ -4119,7 +4119,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 				}
 				channel_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
 					node_id: channel.get().get_counterparty_node_id(),
-					msg: channel.get_mut().get_accept_channel(),
+					msg: channel.get_mut().accept_inbound_channel(),
 				});
 			}
 			hash_map::Entry::Vacant(_) => {
@@ -4149,7 +4149,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 				if !self.default_configuration.manually_accept_inbound_channels {
 					channel_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
 						node_id: counterparty_node_id.clone(),
-						msg: channel.get_accept_channel(),
+						msg: channel.accept_inbound_channel(),
 					});
 				} else {
 					let mut pending_events = self.pending_events.lock().unwrap();