config: add max_funding_satoshis to enforce for inbound channels

Author: valentinewallace

lightning/src/util/config.rs

@@ -100,6 +100,13 @@ pub struct ChannelHandshakeLimits {
 	///
 	/// Default value: 0.
 	pub min_funding_satoshis: u64,
+	/// Maximum allowed satoshis when a channel is funded, this is supplied by the sender and so
+	/// only applies to inbound channels.
+	///
+	/// Default value: 2^24.
+	//  Note that this default was chosen because it was the maximum funding amount prior to wumbo
+	//  channels being introduced.
+	pub max_funding_satoshis: u64,
 	/// The remote node sets a limit on the minimum size of HTLCs we can send to them. This allows
 	/// you to limit the maximum minimum-size they can require.
 	///
@@ -151,6 +158,7 @@ impl Default for ChannelHandshakeLimits {
 	fn default() -> Self {
 		ChannelHandshakeLimits {
 			min_funding_satoshis: 0,
+			max_funding_satoshis: 1 << 24,
 			max_htlc_minimum_msat: <u64>::max_value(),
 			min_max_htlc_value_in_flight_msat: 0,
 			max_channel_reserve_satoshis: <u64>::max_value(),