X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=b88a38b56504eb652c68fb445c29b5e4e4addb5b;hb=10071b51e2b7bafcef1ce958524bd70ef5c7ba5a;hp=8c237992ab75ebd64a9c2860fca0b1210b0fbe0e;hpb=e2f216b694cfc2302e97280f9e9a6775941fd563;p=rust-lightning

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 8c237992..b88a38b5 100644
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -500,9 +500,6 @@ pub(crate) const EXPIRE_PREV_CONFIG_TICKS: usize = 5;
 // Holder designates channel data owned for the benefice of the user client.
 // Counterparty designates channel data owned by the another channel participant entity.
 pub(super) struct Channel<Signer: Sign> {
-	#[cfg(any(test, feature = "_test_utils"))]
-	pub(crate) config: LegacyChannelConfig,
-	#[cfg(not(any(test, feature = "_test_utils")))]
 	config: LegacyChannelConfig,
 
 	// Track the previous `ChannelConfig` so that we can continue forwarding HTLCs that were
@@ -4551,6 +4548,43 @@ impl<Signer: Sign> Channel<Signer> {
 		did_channel_update
 	}
 
+	fn internal_htlc_satisfies_config(
+		&self, htlc: &msgs::UpdateAddHTLC, amt_to_forward: u64, outgoing_cltv_value: u32, config: &ChannelConfig,
+	) -> Result<(), (&'static str, u16)> {
+		let fee = amt_to_forward.checked_mul(config.forwarding_fee_proportional_millionths as u64)
+			.and_then(|prop_fee| (prop_fee / 1000000).checked_add(config.forwarding_fee_base_msat as u64));
+		if fee.is_none() || htlc.amount_msat < fee.unwrap() ||
+			(htlc.amount_msat - fee.unwrap()) < amt_to_forward {
+			return Err((
+				"Prior hop has deviated from specified fees parameters or origin node has obsolete ones",
+				0x1000 | 12, // fee_insufficient
+			));
+		}
+		if (htlc.cltv_expiry as u64) < outgoing_cltv_value as u64 + config.cltv_expiry_delta as u64 {
+			return Err((
+				"Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
+				0x1000 | 13, // incorrect_cltv_expiry
+			));
+		}
+		Ok(())
+	}
+
+	/// Determines whether the parameters of an incoming HTLC to be forwarded satisfy the channel's
+	/// [`ChannelConfig`]. This first looks at the channel's current [`ChannelConfig`], and if
+	/// unsuccessful, falls back to the previous one if one exists.
+	pub fn htlc_satisfies_config(
+		&self, htlc: &msgs::UpdateAddHTLC, amt_to_forward: u64, outgoing_cltv_value: u32,
+	) -> Result<(), (&'static str, u16)> {
+		self.internal_htlc_satisfies_config(&htlc, amt_to_forward, outgoing_cltv_value, &self.config())
+			.or_else(|err| {
+				if let Some(prev_config) = self.prev_config() {
+					self.internal_htlc_satisfies_config(htlc, amt_to_forward, outgoing_cltv_value, &prev_config)
+				} else {
+					Err(err)
+				}
+			})
+	}
+
 	pub fn get_feerate(&self) -> u32 {
 		self.feerate_per_kw
 	}