Persist whether an HTLC is blinded in HTLCPreviousHopData.

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

Another variant will be added to the new Blinded enum when we support
receiving/forwarding as a non-intro node.

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 9941ad6583c7f1cfb929009b7ed63f3311654e58..e3fe74d1a07f9bf67f7a3c83fbd06525c4ebf594 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -225,6 +225,13 @@ pub(super) enum HTLCForwardInfo {
        },
 }
 
+// Used for failing blinded HTLCs backwards correctly.
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+enum BlindedFailure {
+       FromIntroductionNode,
+       // Another variant will be added here for non-intro nodes.
+}
+
 /// Tracks the inbound corresponding to an outbound HTLC
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub(crate) struct HTLCPreviousHopData {
@@ -234,6 +241,7 @@ pub(crate) struct HTLCPreviousHopData {
        htlc_id: u64,
        incoming_packet_shared_secret: [u8; 32],
        phantom_shared_secret: Option<[u8; 32]>,
+       blinded_failure: Option<BlindedFailure>,
 
        // This field is consumed by `claim_funds_from_hop()` when updating a force-closed backwards
        // channel with a preimage provided by the forward channel.
@@ -4072,6 +4080,7 @@ where
                                htlc_id: payment.prev_htlc_id,
                                incoming_packet_shared_secret: payment.forward_info.incoming_shared_secret,
                                phantom_shared_secret: None,
+                               blinded_failure: None,
                        });
 
                        let failure_reason = HTLCFailReason::from_failure_code(0x4000 | 10);
@@ -4120,6 +4129,7 @@ where
                                                                                                        htlc_id: prev_htlc_id,
                                                                                                        incoming_packet_shared_secret: incoming_shared_secret,
                                                                                                        phantom_shared_secret: $phantom_ss,
+                                                                                                       blinded_failure: None,
                                                                                                });
 
                                                                                                let reason = if $next_hop_unknown {
@@ -4236,6 +4246,7 @@ where
                                                                                incoming_packet_shared_secret: incoming_shared_secret,
                                                                                // Phantom payments are only PendingHTLCRouting::Receive.
                                                                                phantom_shared_secret: None,
+                                                                               blinded_failure: None,
                                                                        });
                                                                        if let Err(e) = chan.queue_add_htlc(outgoing_amt_msat,
                                                                                payment_hash, outgoing_cltv_value, htlc_source.clone(),
@@ -4319,6 +4330,7 @@ where
                                                                                htlc_id: prev_htlc_id,
                                                                                incoming_packet_shared_secret: incoming_shared_secret,
                                                                                phantom_shared_secret,
+                                                                               blinded_failure: None,
                                                                        },
                                                                        // We differentiate the received value from the sender intended value
                                                                        // if possible so that we don't prematurely mark MPP payments complete
@@ -4349,6 +4361,7 @@ where
                                                                                                htlc_id: $htlc.prev_hop.htlc_id,
                                                                                                incoming_packet_shared_secret: $htlc.prev_hop.incoming_packet_shared_secret,
                                                                                                phantom_shared_secret,
+                                                                                               blinded_failure: None,
                                                                                        }), payment_hash,
                                                                                        HTLCFailReason::reason(0x4000 | 15, htlc_msat_height_data),
                                                                                        HTLCDestination::FailedPayment { payment_hash: $payment_hash },
@@ -6598,6 +6611,7 @@ where
                                                                                        htlc_id: prev_htlc_id,
                                                                                        incoming_packet_shared_secret: forward_info.incoming_shared_secret,
                                                                                        phantom_shared_secret: None,
+                                                                                       blinded_failure: None,
                                                                                });
 
                                                                                failed_intercept_forwards.push((htlc_source, forward_info.payment_hash,
@@ -8194,6 +8208,7 @@ where
                                                incoming_packet_shared_secret: htlc.forward_info.incoming_shared_secret,
                                                phantom_shared_secret: None,
                                                outpoint: htlc.prev_funding_outpoint,
+                                               blinded_failure: None,
                                        });
 
                                        let requested_forward_scid /* intercept scid */ = match htlc.forward_info.routing {
@@ -9266,10 +9281,15 @@ impl_writeable_tlv_based_enum!(PendingHTLCStatus, ;
        (1, Fail),
 );
 
+impl_writeable_tlv_based_enum!(BlindedFailure,
+       (0, FromIntroductionNode) => {}, ;
+);
+
 impl_writeable_tlv_based!(HTLCPreviousHopData, {
        (0, short_channel_id, required),
        (1, phantom_shared_secret, option),
        (2, outpoint, required),
+       (3, blinded_failure, option),
        (4, htlc_id, required),
        (6, incoming_packet_shared_secret, required),
        (7, user_channel_id, option),