channelmanager: DRY PendingHTLCInfo creation for receives
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 4e493546c23e7be9ddc9a31414e137c14c27be5e..2c99c821468e299b3ad2c6c34f34991d36204aaa 100644 (file)
@@ -48,7 +48,7 @@ use ln::msgs;
 use ln::msgs::NetAddress;
 use ln::onion_utils;
 use ln::msgs::{ChannelMessageHandler, DecodeError, LightningError, MAX_VALUE_MSAT, OptionalField};
-use chain::keysinterface::{Sign, KeysInterface, KeysManager, InMemorySigner};
+use chain::keysinterface::{Sign, KeysInterface, KeysManager, InMemorySigner, Recipient};
 use util::config::UserConfig;
 use util::events::{EventHandler, EventsProvider, MessageSendEvent, MessageSendEventsProvider, ClosureReason};
 use util::{byte_utils, events};
@@ -81,6 +81,7 @@ mod inbound_payment {
        use ln::msgs;
        use ln::msgs::MAX_VALUE_MSAT;
        use util::chacha20::ChaCha20;
+       use util::crypto::hkdf_extract_expand_thrice;
        use util::logger::Logger;
 
        use core::convert::TryInto;
@@ -112,7 +113,13 @@ mod inbound_payment {
 
        impl ExpandedKey {
                pub(super) fn new(key_material: &KeyMaterial) -> ExpandedKey {
-                       hkdf_extract_expand(b"LDK Inbound Payment Key Expansion", &key_material)
+                       let (metadata_key, ldk_pmt_hash_key, user_pmt_hash_key) =
+                               hkdf_extract_expand_thrice(b"LDK Inbound Payment Key Expansion", &key_material.0);
+                       Self {
+                               metadata_key,
+                               ldk_pmt_hash_key,
+                               user_pmt_hash_key,
+                       }
                }
        }
 
@@ -330,31 +337,6 @@ mod inbound_payment {
                }
                return Ok(PaymentPreimage(decoded_payment_preimage))
        }
-
-       fn hkdf_extract_expand(salt: &[u8], ikm: &KeyMaterial) -> ExpandedKey {
-               let mut hmac = HmacEngine::<Sha256>::new(salt);
-               hmac.input(&ikm.0);
-               let prk = Hmac::from_engine(hmac).into_inner();
-               let mut hmac = HmacEngine::<Sha256>::new(&prk[..]);
-               hmac.input(&[1; 1]);
-               let metadata_key = Hmac::from_engine(hmac).into_inner();
-
-               let mut hmac = HmacEngine::<Sha256>::new(&prk[..]);
-               hmac.input(&metadata_key);
-               hmac.input(&[2; 1]);
-               let ldk_pmt_hash_key = Hmac::from_engine(hmac).into_inner();
-
-               let mut hmac = HmacEngine::<Sha256>::new(&prk[..]);
-               hmac.input(&ldk_pmt_hash_key);
-               hmac.input(&[3; 1]);
-               let user_pmt_hash_key = Hmac::from_engine(hmac).into_inner();
-
-               ExpandedKey {
-                       metadata_key,
-                       ldk_pmt_hash_key,
-                       user_pmt_hash_key,
-               }
-       }
 }
 
 // We hold various information about HTLC relay in the HTLC objects in Channel itself:
@@ -536,6 +518,12 @@ pub(super) enum HTLCFailReason {
        }
 }
 
+struct ReceiveError {
+       err_code: u16,
+       err_data: Vec<u8>,
+       msg: &'static str,
+}
+
 /// Return value for claim_funds_from_hop
 enum ClaimFundsFromHop {
        PrevHopForceClosed,
@@ -1697,8 +1685,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        pending_inbound_payments: Mutex::new(HashMap::new()),
                        pending_outbound_payments: Mutex::new(HashMap::new()),
 
-                       our_network_key: keys_manager.get_node_secret(),
-                       our_network_pubkey: PublicKey::from_secret_key(&secp_ctx, &keys_manager.get_node_secret()),
+                       our_network_key: keys_manager.get_node_secret(Recipient::Node).unwrap(),
+                       our_network_pubkey: PublicKey::from_secret_key(&secp_ctx, &keys_manager.get_node_secret(Recipient::Node).unwrap()),
                        secp_ctx,
 
                        inbound_payment_key: expanded_inbound_key,
@@ -2061,6 +2049,102 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                }
        }
 
+       fn construct_recv_pending_htlc_info(&self, hop_data: msgs::OnionHopData, shared_secret: [u8; 32],
+               payment_hash: PaymentHash, amt_msat: u64, cltv_expiry: u32) -> Result<PendingHTLCInfo, ReceiveError>
+       {
+               // final_incorrect_cltv_expiry
+               if hop_data.outgoing_cltv_value != cltv_expiry {
+                       return Err(ReceiveError {
+                               msg: "Upstream node set CLTV to the wrong value",
+                               err_code: 18,
+                               err_data: byte_utils::be32_to_array(cltv_expiry).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).
+               if (hop_data.outgoing_cltv_value as u64) <= self.best_block.read().unwrap().height() as u64 + HTLC_FAIL_BACK_BUFFER as u64 + 1  {
+                       return Err(ReceiveError {
+                               err_code: 17,
+                               err_data: Vec::new(),
+                               msg: "The final CLTV expiry is too soon to handle",
+                       });
+               }
+               if hop_data.amt_to_forward > amt_msat {
+                       return Err(ReceiveError {
+                               err_code: 19,
+                               err_data: byte_utils::be64_to_array(amt_msat).to_vec(),
+                               msg: "Upstream node sent less than we were supposed to receive in payment",
+                       });
+               }
+
+               let routing = match hop_data.format {
+                       msgs::OnionHopDataFormat::Legacy { .. } => {
+                               return Err(ReceiveError {
+                                       err_code: 0x4000|0x2000|3,
+                                       err_data: Vec::new(),
+                                       msg: "We require payment_secrets",
+                               });
+                       },
+                       msgs::OnionHopDataFormat::NonFinalNode { .. } => {
+                               return Err(ReceiveError {
+                                       err_code: 0x4000|22,
+                                       err_data: Vec::new(),
+                                       msg: "Got non final data with an HMAC of 0",
+                               });
+                       },
+                       msgs::OnionHopDataFormat::FinalNode { payment_data, keysend_preimage } => {
+                               if payment_data.is_some() && keysend_preimage.is_some() {
+                                       return Err(ReceiveError {
+                                               err_code: 0x4000|22,
+                                               err_data: Vec::new(),
+                                               msg: "We don't support MPP keysend payments",
+                                       });
+                               } else if let Some(data) = payment_data {
+                                       PendingHTLCRouting::Receive {
+                                               payment_data: data,
+                                               incoming_cltv_expiry: hop_data.outgoing_cltv_value,
+                                       }
+                               } else 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",
+                                               });
+                                       }
+
+                                       PendingHTLCRouting::ReceiveKeysend {
+                                               payment_preimage,
+                                               incoming_cltv_expiry: hop_data.outgoing_cltv_value,
+                                       }
+                               } else {
+                                       return Err(ReceiveError {
+                                               err_code: 0x4000|0x2000|3,
+                                               err_data: Vec::new(),
+                                               msg: "We require payment_secrets",
+                                       });
+                               }
+                       },
+               };
+               Ok(PendingHTLCInfo {
+                       routing,
+                       payment_hash,
+                       incoming_shared_secret: shared_secret,
+                       amt_to_forward: amt_msat,
+                       outgoing_cltv_value: hop_data.outgoing_cltv_value,
+               })
+       }
+
        fn decode_update_add_htlc_onion(&self, msg: &msgs::UpdateAddHTLC) -> (PendingHTLCStatus, MutexGuard<ChannelHolder<Signer>>) {
                macro_rules! return_malformed_err {
                        ($msg: expr, $err_code: expr) => {
@@ -2126,68 +2210,16 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                let pending_forward_info = match next_hop {
                        onion_utils::Hop::Receive(next_hop_data) => {
                                // OUR PAYMENT!
-                               // 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).
-                               if (msg.cltv_expiry as u64) <= self.best_block.read().unwrap().height() as u64 + HTLC_FAIL_BACK_BUFFER as u64 + 1 {
-                                       return_err!("The final CLTV expiry is too soon to handle", 17, &[0;0]);
-                               }
-                               // final_incorrect_htlc_amount
-                               if next_hop_data.amt_to_forward > msg.amount_msat {
-                                       return_err!("Upstream node sent less than we were supposed to receive in payment", 19, &byte_utils::be64_to_array(msg.amount_msat));
-                               }
-                               // final_incorrect_cltv_expiry
-                               if next_hop_data.outgoing_cltv_value != msg.cltv_expiry {
-                                       return_err!("Upstream node set CLTV to the wrong value", 18, &byte_utils::be32_to_array(msg.cltv_expiry));
-                               }
-
-                               let routing = match next_hop_data.format {
-                                       msgs::OnionHopDataFormat::Legacy { .. } => return_err!("We require payment_secrets", 0x4000|0x2000|3, &[0;0]),
-                                       msgs::OnionHopDataFormat::NonFinalNode { .. } => return_err!("Got non final data with an HMAC of 0", 0x4000 | 22, &[0;0]),
-                                       msgs::OnionHopDataFormat::FinalNode { payment_data, keysend_preimage } => {
-                                               if payment_data.is_some() && keysend_preimage.is_some() {
-                                                       return_err!("We don't support MPP keysend payments", 0x4000|22, &[0;0]);
-                                               } else if let Some(data) = payment_data {
-                                                       PendingHTLCRouting::Receive {
-                                                               payment_data: data,
-                                                               incoming_cltv_expiry: msg.cltv_expiry,
-                                                       }
-                                               } else 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 != msg.payment_hash {
-                                                               return_err!("Payment preimage didn't match payment hash", 0x4000|22, &[0;0]);
-                                                       }
-
-                                                       PendingHTLCRouting::ReceiveKeysend {
-                                                               payment_preimage,
-                                                               incoming_cltv_expiry: msg.cltv_expiry,
-                                                       }
-                                               } else {
-                                                       return_err!("We require payment_secrets", 0x4000|0x2000|3, &[0;0]);
-                                               }
+                               match self.construct_recv_pending_htlc_info(next_hop_data, shared_secret, msg.payment_hash, msg.amount_msat, msg.cltv_expiry) {
+                                       Ok(info) => {
+                                               // Note that we could obviously respond immediately with an update_fulfill_htlc
+                                               // message, however that would leak that we are the recipient of this payment, so
+                                               // instead we stay symmetric with the forwarding case, only responding (after a
+                                               // delay) once they've send us a commitment_signed!
+                                               PendingHTLCStatus::Forward(info)
                                        },
-                               };
-
-                               // Note that we could obviously respond immediately with an update_fulfill_htlc
-                               // message, however that would leak that we are the recipient of this payment, so
-                               // instead we stay symmetric with the forwarding case, only responding (after a
-                               // delay) once they've send us a commitment_signed!
-
-                               PendingHTLCStatus::Forward(PendingHTLCInfo {
-                                       routing,
-                                       payment_hash: msg.payment_hash.clone(),
-                                       incoming_shared_secret: shared_secret,
-                                       amt_to_forward: next_hop_data.amt_to_forward,
-                                       outgoing_cltv_value: next_hop_data.outgoing_cltv_value,
-                               })
+                                       Err(ReceiveError { 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 } => {
                                let mut new_pubkey = msg.onion_routing_packet.public_key.unwrap();
@@ -6593,7 +6625,11 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        pending_events_read.append(&mut channel_closures);
                }
 
-               let our_network_pubkey = PublicKey::from_secret_key(&secp_ctx, &args.keys_manager.get_node_secret());
+               let our_network_key = match args.keys_manager.get_node_secret(Recipient::Node) {
+                       Ok(key) => key,
+                       Err(()) => return Err(DecodeError::InvalidValue)
+               };
+               let our_network_pubkey = PublicKey::from_secret_key(&secp_ctx, &our_network_key);
                if let Some(network_pubkey) = received_network_pubkey {
                        if network_pubkey != our_network_pubkey {
                                log_error!(args.logger, "Key that was generated does not match the existing key.");
@@ -6622,7 +6658,7 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        pending_inbound_payments: Mutex::new(pending_inbound_payments),
                        pending_outbound_payments: Mutex::new(pending_outbound_payments.unwrap()),
 
-                       our_network_key: args.keys_manager.get_node_secret(),
+                       our_network_key,
                        our_network_pubkey,
                        secp_ctx,