X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fmsgs.rs;h=004bd3d99d318e2458f41e9c31307614afb93b5f;hb=5b28744755a4a5ef0303c9cbf927502495194055;hp=3042b4d32e0a344e185ef9756654aefa759606aa;hpb=4894d52d30399c21b7994952a8de0d1d7848c58d;p=rust-lightning

diff --git a/lightning/src/ln/msgs.rs b/lightning/src/ln/msgs.rs
index 3042b4d3..004bd3d9 100644
--- a/lightning/src/ln/msgs.rs
+++ b/lightning/src/ln/msgs.rs
@@ -543,7 +543,14 @@ pub struct UnsignedChannelUpdate {
 	pub timestamp: u32,
 	/// Channel flags
 	pub flags: u8,
-	/// The number of blocks to subtract from incoming HTLC cltv_expiry values
+	/// The number of blocks such that if:
+	/// `incoming_htlc.cltv_expiry < outgoing_htlc.cltv_expiry + cltv_expiry_delta`
+	/// then we need to fail the HTLC backwards. When forwarding an HTLC, cltv_expiry_delta determines
+	/// the outgoing HTLC's minimum cltv_expiry value -- so, if an incoming HTLC comes in with a
+	/// cltv_expiry of 100000, and the node we're forwarding to has a cltv_expiry_delta value of 10,
+	/// then we'll check that the outgoing HTLC's cltv_expiry value is at least 100010 before
+	/// forwarding. Note that the HTLC sender is the one who originally sets this value when
+	/// constructing the route.
 	pub cltv_expiry_delta: u16,
 	/// The minimum HTLC size incoming to sender, in milli-satoshi
 	pub htlc_minimum_msat: u64,