- 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 { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
- 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::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, InboundOnionErr> {
- let (payment_data, keysend_preimage, custom_tlvs, onion_amt_msat, outgoing_cltv_value, payment_metadata) = match hop_data {
- msgs::InboundOnionPayload::Receive {
- payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
- } =>
- (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
- msgs::InboundOnionPayload::BlindedReceive {
- amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
- } => {
- let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
- (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
- }
- msgs::InboundOnionPayload::Forward { .. } => {
- 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 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()
- })
- }
- // final_expiry_too_soon
- // We have to have some headroom to broadcast on chain if we have the preimage, so make sure
- // we have at least HTLC_FAIL_BACK_BUFFER blocks to go.
- //
- // Also, ensure that, in the case of an unknown preimage for the received payment hash, our
- // 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 cltv_expiry <= current_height + HTLC_FAIL_BACK_BUFFER + 1 {
- let mut err_data = Vec::with_capacity(12);
- err_data.extend_from_slice(&amt_msat.to_be_bytes());
- err_data.extend_from_slice(¤t_height.to_be_bytes());
- return Err(InboundOnionErr {
- err_code: 0x4000 | 15, err_data,
- msg: "The final CLTV expiry is too soon to handle",
- });
- }
- 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(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 = 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: "Payment preimage didn't match payment hash",
- });
- }
- 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,
- custom_tlvs,
- }
- } else if let Some(data) = payment_data {
- PendingHTLCRouting::Receive {
- payment_data: data,
- payment_metadata,
- incoming_cltv_expiry: outgoing_cltv_value,
- phantom_shared_secret,
- custom_tlvs,
- }
- } 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: onion_amt_msat,
- outgoing_cltv_value,
- skimmed_fee_msat: counterparty_skimmed_fee_msat,
- })
- }
-