Allow forwarding HTLCs that were constructed for previous config

[rust-lightning] / lightning / src / ln / channelmanager.rs

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index fcd53b502f24946b2d8dee96bb636075834b2e6d..ef37dabc8ade68150602216d2ae42ad29fc67d4d 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -2230,7 +2230,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                },
                                                Some(id) => Some(id.clone()),
                                        };
-                                       let (chan_update_opt, forwardee_cltv_expiry_delta) = if let Some(forwarding_id) = forwarding_id_opt {
+                                       let chan_update_opt = if let Some(forwarding_id) = forwarding_id_opt {
                                                let chan = channel_state.as_mut().unwrap().by_id.get_mut(&forwarding_id).unwrap();
                                                if !chan.should_announce() && !self.default_configuration.accept_forwards_to_priv_channels {
                                                        // Note that the behavior here should be identical to the above block - we
@@ -2257,18 +2257,20 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                if *amt_to_forward < chan.get_counterparty_htlc_minimum_msat() { // amount_below_minimum
                                                        break Some(("HTLC amount was below the htlc_minimum_msat", 0x1000 | 11, chan_update_opt));
                                                }
-                                               let fee = amt_to_forward.checked_mul(chan.get_fee_proportional_millionths() as u64)
-                                                       .and_then(|prop_fee| { (prop_fee / 1000000)
-                                                       .checked_add(chan.get_outbound_forwarding_fee_base_msat() as u64) });
-                                               if fee.is_none() || msg.amount_msat < fee.unwrap() || (msg.amount_msat - fee.unwrap()) < *amt_to_forward { // fee_insufficient
-                                                       break Some(("Prior hop has deviated from specified fees parameters or origin node has obsolete ones", 0x1000 | 12, chan_update_opt));
+                                               if let Err((err, code)) = chan.htlc_satisfies_config(&msg, *amt_to_forward, *outgoing_cltv_value) {
+                                                       break Some((err, code, chan_update_opt));
                                                }
-                                               (chan_update_opt, chan.get_cltv_expiry_delta())
-                                       } else { (None, MIN_CLTV_EXPIRY_DELTA) };
+                                               chan_update_opt
+                                       } else {
+                                               if (msg.cltv_expiry as u64) < (*outgoing_cltv_value) as u64 + MIN_CLTV_EXPIRY_DELTA as u64 { // incorrect_cltv_expiry
+                                                       break Some((
+                                                               "Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
+                                                               0x1000 | 13, None,
+                                                       ));
+                                               }
+                                               None
+                                       };
 
-                                       if (msg.cltv_expiry as u64) < (*outgoing_cltv_value) as u64 + forwardee_cltv_expiry_delta as u64 { // incorrect_cltv_expiry
-                                               break Some(("Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta", 0x1000 | 13, chan_update_opt));
-                                       }
                                        let cur_height = self.best_block.read().unwrap().height() + 1;
                                        // Theoretically, channel counterparty shouldn't send us a HTLC expiring now,
                                        // but we want to be robust wrt to counterparty packet sanitization (see