Merge pull request #2128 from valentinewallace/2023-03-route-blinding-groundwork
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 6cd4799ff3cf77063e5b313e8a6d6a70631373a7..3757b06b3c94dc3b5f2bfca20d6096796980f9a1 100644 (file)
@@ -341,7 +341,7 @@ impl HTLCSource {
        }
 }
 
-struct ReceiveError {
+struct InboundOnionErr {
        err_code: u16,
        err_data: Vec<u8>,
        msg: &'static str,
@@ -2631,14 +2631,64 @@ where
                }
        }
 
+       fn construct_fwd_pending_htlc_info(
+               &self, msg: &msgs::UpdateAddHTLC, hop_data: msgs::InboundOnionPayload, hop_hmac: [u8; 32],
+               new_packet_bytes: [u8; onion_utils::ONION_DATA_LEN], shared_secret: [u8; 32],
+               next_packet_pubkey_opt: Option<Result<PublicKey, secp256k1::Error>>
+       ) -> Result<PendingHTLCInfo, InboundOnionErr> {
+               debug_assert!(next_packet_pubkey_opt.is_some());
+               let outgoing_packet = msgs::OnionPacket {
+                       version: 0,
+                       public_key: next_packet_pubkey_opt.unwrap_or(Err(secp256k1::Error::InvalidPublicKey)),
+                       hop_data: new_packet_bytes,
+                       hmac: hop_hmac,
+               };
+
+               let (short_channel_id, amt_to_forward, outgoing_cltv_value) = match hop_data {
+                       msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
+                               (short_channel_id, amt_to_forward, outgoing_cltv_value),
+                       msgs::InboundOnionPayload::Receive { .. } =>
+                               return Err(InboundOnionErr {
+                                       msg: "Final Node OnionHopData provided for us as an intermediary node",
+                                       err_code: 0x4000 | 22,
+                                       err_data: Vec::new(),
+                               }),
+               };
+
+               Ok(PendingHTLCInfo {
+                       routing: PendingHTLCRouting::Forward {
+                               onion_packet: outgoing_packet,
+                               short_channel_id,
+                       },
+                       payment_hash: msg.payment_hash,
+                       incoming_shared_secret: shared_secret,
+                       incoming_amt_msat: Some(msg.amount_msat),
+                       outgoing_amt_msat: amt_to_forward,
+                       outgoing_cltv_value,
+                       skimmed_fee_msat: None,
+               })
+       }
+
        fn construct_recv_pending_htlc_info(
-               &self, hop_data: msgs::OnionHopData, shared_secret: [u8; 32], payment_hash: PaymentHash,
+               &self, hop_data: msgs::InboundOnionPayload, shared_secret: [u8; 32], payment_hash: PaymentHash,
                amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>, allow_underpay: bool,
                counterparty_skimmed_fee_msat: Option<u64>,
-       ) -> Result<PendingHTLCInfo, ReceiveError> {
+       ) -> Result<PendingHTLCInfo, InboundOnionErr> {
+               let (payment_data, keysend_preimage, onion_amt_msat, outgoing_cltv_value, payment_metadata) = match hop_data {
+                       msgs::InboundOnionPayload::Receive {
+                               payment_data, keysend_preimage, amt_msat, outgoing_cltv_value, payment_metadata, ..
+                       } =>
+                               (payment_data, keysend_preimage, amt_msat, outgoing_cltv_value, payment_metadata),
+                       _ =>
+                               return Err(InboundOnionErr {
+                                       err_code: 0x4000|22,
+                                       err_data: Vec::new(),
+                                       msg: "Got non final data with an HMAC of 0",
+                               }),
+               };
                // final_incorrect_cltv_expiry
-               if hop_data.outgoing_cltv_value > cltv_expiry {
-                       return Err(ReceiveError {
+               if outgoing_cltv_value > cltv_expiry {
+                       return Err(InboundOnionErr {
                                msg: "Upstream node set CLTV to less than the CLTV set by the sender",
                                err_code: 18,
                                err_data: cltv_expiry.to_be_bytes().to_vec()
@@ -2652,85 +2702,74 @@ where
                // payment logic has enough time to fail the HTLC backward before our onchain logic triggers a
                // channel closure (see HTLC_FAIL_BACK_BUFFER rationale).
                let current_height: u32 = self.best_block.read().unwrap().height();
-               if (hop_data.outgoing_cltv_value as u64) <= current_height as u64 + HTLC_FAIL_BACK_BUFFER as u64 + 1 {
+               if (outgoing_cltv_value as u64) <= current_height as u64 + HTLC_FAIL_BACK_BUFFER as u64 + 1 {
                        let mut err_data = Vec::with_capacity(12);
                        err_data.extend_from_slice(&amt_msat.to_be_bytes());
                        err_data.extend_from_slice(&current_height.to_be_bytes());
-                       return Err(ReceiveError {
+                       return Err(InboundOnionErr {
                                err_code: 0x4000 | 15, err_data,
                                msg: "The final CLTV expiry is too soon to handle",
                        });
                }
-               if (!allow_underpay && hop_data.amt_to_forward > amt_msat) ||
-                       (allow_underpay && hop_data.amt_to_forward >
+               if (!allow_underpay && onion_amt_msat > amt_msat) ||
+                       (allow_underpay && onion_amt_msat >
                         amt_msat.saturating_add(counterparty_skimmed_fee_msat.unwrap_or(0)))
                {
-                       return Err(ReceiveError {
+                       return Err(InboundOnionErr {
                                err_code: 19,
                                err_data: amt_msat.to_be_bytes().to_vec(),
                                msg: "Upstream node sent less than we were supposed to receive in payment",
                        });
                }
 
-               let routing = match hop_data.format {
-                       msgs::OnionHopDataFormat::NonFinalNode { .. } => {
-                               return Err(ReceiveError {
+               let routing = if let Some(payment_preimage) = keysend_preimage {
+                       // We need to check that the sender knows the keysend preimage before processing this
+                       // payment further. Otherwise, an intermediary routing hop forwarding non-keysend-HTLC X
+                       // could discover the final destination of X, by probing the adjacent nodes on the route
+                       // with a keysend payment of identical payment hash to X and observing the processing
+                       // time discrepancies due to a hash collision with X.
+                       let hashed_preimage = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
+                       if hashed_preimage != payment_hash {
+                               return Err(InboundOnionErr {
                                        err_code: 0x4000|22,
                                        err_data: Vec::new(),
-                                       msg: "Got non final data with an HMAC of 0",
+                                       msg: "Payment preimage didn't match payment hash",
                                });
-                       },
-                       msgs::OnionHopDataFormat::FinalNode { payment_data, keysend_preimage, payment_metadata } => {
-                               if let Some(payment_preimage) = keysend_preimage {
-                                       // We need to check that the sender knows the keysend preimage before processing this
-                                       // payment further. Otherwise, an intermediary routing hop forwarding non-keysend-HTLC X
-                                       // could discover the final destination of X, by probing the adjacent nodes on the route
-                                       // with a keysend payment of identical payment hash to X and observing the processing
-                                       // time discrepancies due to a hash collision with X.
-                                       let hashed_preimage = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
-                                       if hashed_preimage != payment_hash {
-                                               return Err(ReceiveError {
-                                                       err_code: 0x4000|22,
-                                                       err_data: Vec::new(),
-                                                       msg: "Payment preimage didn't match payment hash",
-                                               });
-                                       }
-                                       if !self.default_configuration.accept_mpp_keysend && payment_data.is_some() {
-                                               return Err(ReceiveError {
-                                                       err_code: 0x4000|22,
-                                                       err_data: Vec::new(),
-                                                       msg: "We don't support MPP keysend payments",
-                                               });
-                                       }
-                                       PendingHTLCRouting::ReceiveKeysend {
-                                               payment_data,
-                                               payment_preimage,
-                                               payment_metadata,
-                                               incoming_cltv_expiry: hop_data.outgoing_cltv_value,
-                                       }
-                               } else if let Some(data) = payment_data {
-                                       PendingHTLCRouting::Receive {
-                                               payment_data: data,
-                                               payment_metadata,
-                                               incoming_cltv_expiry: hop_data.outgoing_cltv_value,
-                                               phantom_shared_secret,
-                                       }
-                               } else {
-                                       return Err(ReceiveError {
-                                               err_code: 0x4000|0x2000|3,
-                                               err_data: Vec::new(),
-                                               msg: "We require payment_secrets",
-                                       });
-                               }
-                       },
+                       }
+                       if !self.default_configuration.accept_mpp_keysend && payment_data.is_some() {
+                               return Err(InboundOnionErr {
+                                       err_code: 0x4000|22,
+                                       err_data: Vec::new(),
+                                       msg: "We don't support MPP keysend payments",
+                               });
+                       }
+                       PendingHTLCRouting::ReceiveKeysend {
+                               payment_data,
+                               payment_preimage,
+                               payment_metadata,
+                               incoming_cltv_expiry: outgoing_cltv_value,
+                       }
+               } else if let Some(data) = payment_data {
+                       PendingHTLCRouting::Receive {
+                               payment_data: data,
+                               payment_metadata,
+                               incoming_cltv_expiry: outgoing_cltv_value,
+                               phantom_shared_secret,
+                       }
+               } else {
+                       return Err(InboundOnionErr {
+                               err_code: 0x4000|0x2000|3,
+                               err_data: Vec::new(),
+                               msg: "We require payment_secrets",
+                       });
                };
                Ok(PendingHTLCInfo {
                        routing,
                        payment_hash,
                        incoming_shared_secret: shared_secret,
                        incoming_amt_msat: Some(amt_msat),
-                       outgoing_amt_msat: hop_data.amt_to_forward,
-                       outgoing_cltv_value: hop_data.outgoing_cltv_value,
+                       outgoing_amt_msat: onion_amt_msat,
+                       outgoing_cltv_value,
                        skimmed_fee_msat: counterparty_skimmed_fee_msat,
                })
        }
@@ -2794,9 +2833,8 @@ where
                };
                let (outgoing_scid, outgoing_amt_msat, outgoing_cltv_value, next_packet_pk_opt) = match next_hop {
                        onion_utils::Hop::Forward {
-                               next_hop_data: msgs::OnionHopData {
-                                       format: msgs::OnionHopDataFormat::NonFinalNode { short_channel_id }, amt_to_forward,
-                                       outgoing_cltv_value,
+                               next_hop_data: msgs::InboundOnionPayload::Forward {
+                                       short_channel_id, amt_to_forward, outgoing_cltv_value
                                }, ..
                        } => {
                                let next_pk = onion_utils::next_hop_packet_pubkey(&self.secp_ctx,
@@ -2806,9 +2844,7 @@ where
                        // We'll do receive checks in [`Self::construct_pending_htlc_info`] so we have access to the
                        // inbound channel's state.
                        onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
-                       onion_utils::Hop::Forward {
-                               next_hop_data: msgs::OnionHopData { format: msgs::OnionHopDataFormat::FinalNode { .. }, .. }, ..
-                       } => {
+                       onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } => {
                                return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
                        }
                };
@@ -2979,37 +3015,15 @@ where
                                                // delay) once they've send us a commitment_signed!
                                                PendingHTLCStatus::Forward(info)
                                        },
-                                       Err(ReceiveError { err_code, err_data, msg }) => return_err!(msg, err_code, &err_data)
+                                       Err(InboundOnionErr { err_code, err_data, msg }) => return_err!(msg, err_code, &err_data)
                                }
                        },
                        onion_utils::Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes } => {
-                               debug_assert!(next_packet_pubkey_opt.is_some());
-                               let outgoing_packet = msgs::OnionPacket {
-                                       version: 0,
-                                       public_key: next_packet_pubkey_opt.unwrap_or(Err(secp256k1::Error::InvalidPublicKey)),
-                                       hop_data: new_packet_bytes,
-                                       hmac: next_hop_hmac.clone(),
-                               };
-
-                               let short_channel_id = match next_hop_data.format {
-                                       msgs::OnionHopDataFormat::NonFinalNode { short_channel_id } => short_channel_id,
-                                       msgs::OnionHopDataFormat::FinalNode { .. } => {
-                                               return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0;0]);
-                                       },
-                               };
-
-                               PendingHTLCStatus::Forward(PendingHTLCInfo {
-                                       routing: PendingHTLCRouting::Forward {
-                                               onion_packet: outgoing_packet,
-                                               short_channel_id,
-                                       },
-                                       payment_hash: msg.payment_hash.clone(),
-                                       incoming_shared_secret: shared_secret,
-                                       incoming_amt_msat: Some(msg.amount_msat),
-                                       outgoing_amt_msat: next_hop_data.amt_to_forward,
-                                       outgoing_cltv_value: next_hop_data.outgoing_cltv_value,
-                                       skimmed_fee_msat: None,
-                               })
+                               match self.construct_fwd_pending_htlc_info(msg, next_hop_data, next_hop_hmac,
+                                       new_packet_bytes, shared_secret, next_packet_pubkey_opt) {
+                                       Ok(info) => PendingHTLCStatus::Forward(info),
+                                       Err(InboundOnionErr { err_code, err_data, msg }) => return_err!(msg, err_code, &err_data)
+                               }
                        }
                }
        }
@@ -3814,7 +3828,7 @@ where
                                                                                                                        outgoing_cltv_value, Some(phantom_shared_secret), false, None)
                                                                                                                {
                                                                                                                        Ok(info) => phantom_receives.push((prev_short_channel_id, prev_funding_outpoint, prev_user_channel_id, vec![(info, prev_htlc_id)])),
-                                                                                                                       Err(ReceiveError { err_code, err_data, msg }) => failed_payment!(msg, err_code, err_data, Some(phantom_shared_secret))
+                                                                                                                       Err(InboundOnionErr { err_code, err_data, msg }) => failed_payment!(msg, err_code, err_data, Some(phantom_shared_secret))
                                                                                                                }
                                                                                                        },
                                                                                                        _ => panic!(),
@@ -10070,20 +10084,18 @@ mod tests {
                let node = create_network(1, &node_cfg, &node_chanmgr);
                let sender_intended_amt_msat = 100;
                let extra_fee_msat = 10;
-               let hop_data = msgs::OnionHopData {
-                       amt_to_forward: 100,
+               let hop_data = msgs::InboundOnionPayload::Receive {
+                       amt_msat: 100,
                        outgoing_cltv_value: 42,
-                       format: msgs::OnionHopDataFormat::FinalNode {
-                               keysend_preimage: None,
-                               payment_metadata: None,
-                               payment_data: Some(msgs::FinalOnionHopData {
-                                       payment_secret: PaymentSecret([0; 32]), total_msat: sender_intended_amt_msat,
-                               }),
-                       }
+                       payment_metadata: None,
+                       keysend_preimage: None,
+                       payment_data: Some(msgs::FinalOnionHopData {
+                               payment_secret: PaymentSecret([0; 32]), total_msat: sender_intended_amt_msat,
+                       }),
                };
                // Check that if the amount we received + the penultimate hop extra fee is less than the sender
                // intended amount, we fail the payment.
-               if let Err(crate::ln::channelmanager::ReceiveError { err_code, .. }) =
+               if let Err(crate::ln::channelmanager::InboundOnionErr { err_code, .. }) =
                        node[0].node.construct_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
                                sender_intended_amt_msat - extra_fee_msat - 1, 42, None, true, Some(extra_fee_msat))
                {
@@ -10091,16 +10103,14 @@ mod tests {
                } else { panic!(); }
 
                // If amt_received + extra_fee is equal to the sender intended amount, we're fine.
-               let hop_data = msgs::OnionHopData { // This is the same hop_data as above, OnionHopData doesn't implement Clone
-                       amt_to_forward: 100,
+               let hop_data = msgs::InboundOnionPayload::Receive { // This is the same payload as above, InboundOnionPayload doesn't implement Clone
+                       amt_msat: 100,
                        outgoing_cltv_value: 42,
-                       format: msgs::OnionHopDataFormat::FinalNode {
-                               keysend_preimage: None,
-                               payment_metadata: None,
-                               payment_data: Some(msgs::FinalOnionHopData {
-                                       payment_secret: PaymentSecret([0; 32]), total_msat: sender_intended_amt_msat,
-                               }),
-                       }
+                       payment_metadata: None,
+                       keysend_preimage: None,
+                       payment_data: Some(msgs::FinalOnionHopData {
+                               payment_secret: PaymentSecret([0; 32]), total_msat: sender_intended_amt_msat,
+                       }),
                };
                assert!(node[0].node.construct_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
                        sender_intended_amt_msat - extra_fee_msat, 42, None, true, Some(extra_fee_msat)).is_ok());