Remove Channel::counterparty_htlc_minimum_msat

Author: ViktorTigerstrom

lightning/src/ln/channel.rs

@@ -631,7 +631,6 @@ pub(super) struct Channel<Signer: Sign> {
 	#[cfg(not(test))]
 	holder_selected_channel_reserve_satoshis: u64,
 
-	counterparty_htlc_minimum_msat: u64,
 	holder_htlc_minimum_msat: u64,
 	#[cfg(test)]
 	pub counterparty_max_accepted_htlcs: u16,
@@ -924,7 +923,6 @@ impl<Signer: Sign> Channel<Signer> {
 			holder_max_htlc_value_in_flight_msat: Self::get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis),
 			counterparty_selected_channel_reserve_satoshis: None, // Filled in in accept_channel
 			holder_selected_channel_reserve_satoshis,
-			counterparty_htlc_minimum_msat: 0,
 			holder_htlc_minimum_msat: if config.own_channel_config.our_htlc_minimum_msat == 0 { 1 } else { config.own_channel_config.our_htlc_minimum_msat },
 			counterparty_max_accepted_htlcs: 0,
 			minimum_depth: None, // Filled in in accept_channel
@@ -1230,12 +1228,17 @@ impl<Signer: Sign> Channel<Signer> {
 			holder_max_htlc_value_in_flight_msat: Self::get_holder_max_htlc_value_in_flight_msat(msg.funding_satoshis),
 			counterparty_selected_channel_reserve_satoshis: Some(msg.channel_reserve_satoshis),
 			holder_selected_channel_reserve_satoshis,
-			counterparty_htlc_minimum_msat: msg.htlc_minimum_msat,
 			holder_htlc_minimum_msat: if config.own_channel_config.our_htlc_minimum_msat == 0 { 1 } else { config.own_channel_config.our_htlc_minimum_msat },
 			counterparty_max_accepted_htlcs: msg.max_accepted_htlcs,
 			minimum_depth: Some(config.own_channel_config.minimum_depth),
 
-			counterparty_forwarding_info: None,
+			counterparty_forwarding_info: Some(CounterpartyForwardingInfo {
+				fee_base_msat: 0,
+				fee_proportional_millionths: 0,
+				cltv_expiry_delta: 0,
+				outbound_htlc_minimum_msat: Some(msg.htlc_minimum_msat),
+				outbound_htlc_maximum_msat: None,
+			}),
 
 			channel_transaction_parameters: ChannelTransactionParameters {
 				holder_pubkeys: pubkeys,
@@ -1949,8 +1952,15 @@ impl<Signer: Sign> Channel<Signer> {
 		self.counterparty_dust_limit_satoshis = msg.dust_limit_satoshis;
 		self.counterparty_max_htlc_value_in_flight_msat = cmp::min(msg.max_htlc_value_in_flight_msat, self.channel_value_satoshis * 1000);
 		self.counterparty_selected_channel_reserve_satoshis = Some(msg.channel_reserve_satoshis);
-		self.counterparty_htlc_minimum_msat = msg.htlc_minimum_msat;
 		self.counterparty_max_accepted_htlcs = msg.max_accepted_htlcs;
+		self.counterparty_forwarding_info = Some(CounterpartyForwardingInfo {
+			fee_base_msat: 0,
+			fee_proportional_millionths: 0,
+			cltv_expiry_delta: 0,
+			outbound_htlc_minimum_msat: Some(msg.htlc_minimum_msat),
+			outbound_htlc_maximum_msat: self.get_counterparty_htlc_maximum_msat(),
+		});
+
 		self.minimum_depth = Some(msg.minimum_depth);
 
 		let counterparty_pubkeys = ChannelPublicKeys {
@@ -4307,7 +4317,7 @@ impl<Signer: Sign> Channel<Signer> {
 
 	/// Allowed in any state (including after shutdown)
 	pub fn get_counterparty_htlc_minimum_msat(&self) -> u64 {
-		self.counterparty_htlc_minimum_msat
+		self.counterparty_forwarding_info.as_ref().map(|info| info.outbound_htlc_minimum_msat.unwrap_or(0)).unwrap_or(0)
 	}
 
 	/// Allowed in any state (including after shutdown), but will return none before TheirInitSent
@@ -5103,8 +5113,9 @@ impl<Signer: Sign> Channel<Signer> {
 			return Err(ChannelError::Ignore("Cannot send 0-msat HTLC".to_owned()));
 		}
 
-		if amount_msat < self.counterparty_htlc_minimum_msat {
-			return Err(ChannelError::Ignore(format!("Cannot send less than their minimum HTLC value ({})", self.counterparty_htlc_minimum_msat)));
+		let counterparty_htlc_minimum_msat = self.get_counterparty_htlc_minimum_msat();
+		if amount_msat < counterparty_htlc_minimum_msat {
+			return Err(ChannelError::Ignore(format!("Cannot send less than their minimum HTLC value ({})", counterparty_htlc_minimum_msat)));
 		}
 
 		if (self.channel_state & (ChannelState::PeerDisconnected as u32)) != 0 {
@@ -5775,7 +5786,11 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
 		// Note that this field is ignored by 0.0.99+ as the TLV Optional variant is used instead.
 		self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0).write(writer)?;
 
-		self.counterparty_htlc_minimum_msat.write(writer)?;
+		// Versions prior to 0.0.107, stored the `outbound_htlc_minimum_msat` field as a
+		// non-optional field of the `Channel` struct, which was written here. It has since been
+		// refactored to be part of the `CounterpartyForwardingInfo` struct.
+		self.counterparty_forwarding_info.as_ref()
+			.map(|info| info.outbound_htlc_minimum_msat.unwrap_or(0)).unwrap_or(0).write(writer)?;
 		self.holder_htlc_minimum_msat.write(writer)?;
 		self.counterparty_max_accepted_htlcs.write(writer)?;
 
@@ -6036,7 +6051,10 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<(&'a K, u32)> for Channel<Signer>
 			// Read the 8 bytes of backwards-compatibility data.
 			let _dummy: u64 = Readable::read(reader)?;
 		}
-		let counterparty_htlc_minimum_msat = Readable::read(reader)?;
+		// Versions prior to 0.0.107, stored the `outbound_htlc_minimum_msat` field as a
+		// non-optional field of the `Channel` struct, which has since been refactored to be part
+		// of the `CounterpartyForwardingInfo` struct. It's therefore read here.
+		let outbound_htlc_minimum_msat = Readable::read(reader)?;
 		let holder_htlc_minimum_msat = Readable::read(reader)?;
 		let counterparty_max_accepted_htlcs = Readable::read(reader)?;
 
@@ -6055,7 +6073,7 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<(&'a K, u32)> for Channel<Signer>
 				fee_base_msat: Readable::read(reader)?,
 				fee_proportional_millionths: Readable::read(reader)?,
 				cltv_expiry_delta: Readable::read(reader)?,
-				outbound_htlc_minimum_msat: Some(counterparty_htlc_minimum_msat),
+				outbound_htlc_minimum_msat: Some(outbound_htlc_minimum_msat),
 				outbound_htlc_maximum_msat: None,
 			}),
 			_ => return Err(DecodeError::InvalidValue),
@@ -6238,7 +6256,6 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<(&'a K, u32)> for Channel<Signer>
 			holder_max_htlc_value_in_flight_msat: holder_max_htlc_value_in_flight_msat.unwrap(),
 			counterparty_selected_channel_reserve_satoshis,
 			holder_selected_channel_reserve_satoshis: holder_selected_channel_reserve_satoshis.unwrap(),
-			counterparty_htlc_minimum_msat,
 			holder_htlc_minimum_msat,
 			counterparty_max_accepted_htlcs,
 			minimum_depth,