Set HTLCPreviousHopData::blinded on intro node forward.

Useful so we know to fail back blinded HTLCs where we are the intro node with
the invalid_onion_blinding error per BOLT 4.

We don't set this field for blinded received HTLCs because we don't support
receiving to multi-hop blinded paths yet, and there's no point in setting it
for HTLCs received to 1-hop blinded paths because per the spec they should fail
back using an unblinded error code.

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index e3fe74d1a07f9bf67f7a3c83fbd06525c4ebf594..9861729d7781b1c4c1f3417df8c6a6aede365afa 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -167,6 +167,18 @@ pub struct BlindedForward {
        // Another field will be added here when we support forwarding as a non-intro node.
 }
 
+impl PendingHTLCRouting {
+       // Used to override the onion failure code and data if the HTLC is blinded.
+       fn blinded_failure(&self) -> Option<BlindedFailure> {
+               // TODO: needs update when we support receiving to multi-hop blinded paths
+               if let Self::Forward { blinded: Some(_), .. } = self {
+                       Some(BlindedFailure::FromIntroductionNode)
+               } else {
+                       None
+               }
+       }
+}
+
 /// Full details of an incoming HTLC, including routing info.
 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 pub struct PendingHTLCInfo {
@@ -4080,7 +4092,7 @@ where
                                htlc_id: payment.prev_htlc_id,
                                incoming_packet_shared_secret: payment.forward_info.incoming_shared_secret,
                                phantom_shared_secret: None,
-                               blinded_failure: None,
+                               blinded_failure: payment.forward_info.routing.blinded_failure(),
                        });
 
                        let failure_reason = HTLCFailReason::from_failure_code(0x4000 | 10);
@@ -4129,7 +4141,7 @@ where
                                                                                                        htlc_id: prev_htlc_id,
                                                                                                        incoming_packet_shared_secret: incoming_shared_secret,
                                                                                                        phantom_shared_secret: $phantom_ss,
-                                                                                                       blinded_failure: None,
+                                                                                                       blinded_failure: routing.blinded_failure(),
                                                                                                });
 
                                                                                                let reason = if $next_hop_unknown {
@@ -4159,7 +4171,7 @@ where
                                                                                                }
                                                                                        }
                                                                                }
-                                                                               if let PendingHTLCRouting::Forward { onion_packet, .. } = routing {
+                                                                               if let PendingHTLCRouting::Forward { ref onion_packet, .. } = routing {
                                                                                        let phantom_pubkey_res = self.node_signer.get_node_id(Recipient::PhantomNode);
                                                                                        if phantom_pubkey_res.is_ok() && fake_scid::is_valid_phantom(&self.fake_scid_rand_bytes, short_chan_id, &self.chain_hash) {
                                                                                                let phantom_shared_secret = self.node_signer.ecdh(Recipient::PhantomNode, &onion_packet.public_key.unwrap(), None).unwrap().secret_bytes();
@@ -4234,7 +4246,9 @@ where
                                                                        prev_short_channel_id, prev_htlc_id, prev_funding_outpoint, prev_user_channel_id,
                                                                        forward_info: PendingHTLCInfo {
                                                                                incoming_shared_secret, payment_hash, outgoing_amt_msat, outgoing_cltv_value,
-                                                                               routing: PendingHTLCRouting::Forward { onion_packet, .. }, skimmed_fee_msat, ..
+                                                                               routing: PendingHTLCRouting::Forward {
+                                                                                       onion_packet, blinded, ..
+                                                                               }, skimmed_fee_msat, ..
                                                                        },
                                                                }) => {
                                                                        log_trace!(self.logger, "Adding HTLC from short id {} with payment_hash {} to channel with short id {} after delay", prev_short_channel_id, &payment_hash, short_chan_id);
@@ -4246,7 +4260,7 @@ where
                                                                                incoming_packet_shared_secret: incoming_shared_secret,
                                                                                // Phantom payments are only PendingHTLCRouting::Receive.
                                                                                phantom_shared_secret: None,
-                                                                               blinded_failure: None,
+                                                                               blinded_failure: blinded.map(|_| BlindedFailure::FromIntroductionNode),
                                                                        });
                                                                        if let Err(e) = chan.queue_add_htlc(outgoing_amt_msat,
                                                                                payment_hash, outgoing_cltv_value, htlc_source.clone(),
@@ -4301,6 +4315,7 @@ where
                                                                        skimmed_fee_msat, ..
                                                                }
                                                        }) => {
+                                                               let blinded_failure = routing.blinded_failure();
                                                                let (cltv_expiry, onion_payload, payment_data, phantom_shared_secret, mut onion_fields) = match routing {
                                                                        PendingHTLCRouting::Receive { payment_data, payment_metadata, incoming_cltv_expiry, phantom_shared_secret, custom_tlvs } => {
                                                                                let _legacy_hop_data = Some(payment_data.clone());
@@ -4330,7 +4345,7 @@ where
                                                                                htlc_id: prev_htlc_id,
                                                                                incoming_packet_shared_secret: incoming_shared_secret,
                                                                                phantom_shared_secret,
-                                                                               blinded_failure: None,
+                                                                               blinded_failure,
                                                                        },
                                                                        // We differentiate the received value from the sender intended value
                                                                        // if possible so that we don't prematurely mark MPP payments complete
@@ -6611,7 +6626,7 @@ where
                                                                                        htlc_id: prev_htlc_id,
                                                                                        incoming_packet_shared_secret: forward_info.incoming_shared_secret,
                                                                                        phantom_shared_secret: None,
-                                                                                       blinded_failure: None,
+                                                                                       blinded_failure: forward_info.routing.blinded_failure(),
                                                                                });
 
                                                                                failed_intercept_forwards.push((htlc_source, forward_info.payment_hash,
@@ -8208,7 +8223,7 @@ where
                                                incoming_packet_shared_secret: htlc.forward_info.incoming_shared_secret,
                                                phantom_shared_secret: None,
                                                outpoint: htlc.prev_funding_outpoint,
-                                               blinded_failure: None,
+                                               blinded_failure: htlc.forward_info.routing.blinded_failure(),
                                        });
 
                                        let requested_forward_scid /* intercept scid */ = match htlc.forward_info.routing {