Make the PaymentSecret in `PaymentReceived` events non-Optional
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 6adef4f6e20e9c7beeedac4676ae5647a8bbebd9..b1890853ec10630f4953f61cae03f99c4310a56d 100644 (file)
@@ -36,6 +36,7 @@ use bitcoin::secp256k1::ecdh::SharedSecret;
 use bitcoin::secp256k1;
 
 use chain;
+use chain::Confirm;
 use chain::Watch;
 use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
 use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, ChannelMonitorUpdateErr, HTLC_FAIL_BACK_BUFFER, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY, MonitorEvent, CLOSED_CHANNEL_UPDATE_ID};
@@ -95,7 +96,7 @@ enum PendingHTLCRouting {
                short_channel_id: u64, // This should be NonZero<u64> eventually when we bump MSRV
        },
        Receive {
-               payment_data: Option<msgs::FinalOnionHopData>,
+               payment_data: msgs::FinalOnionHopData,
                incoming_cltv_expiry: u32, // Used to track when we should expire pending HTLCs that go unclaimed
        },
 }
@@ -155,11 +156,10 @@ pub(crate) struct HTLCPreviousHopData {
 struct ClaimableHTLC {
        prev_hop: HTLCPreviousHopData,
        value: u64,
-       /// Filled in when the HTLC was received with a payment_secret packet, which contains a
-       /// total_msat (which may differ from value if this is a Multi-Path Payment) and a
+       /// Contains a total_msat (which may differ from value if this is a Multi-Path Payment) and a
        /// payment_secret which prevents path-probing attacks and can associate different HTLCs which
        /// are part of the same payment.
-       payment_data: Option<msgs::FinalOnionHopData>,
+       payment_data: msgs::FinalOnionHopData,
        cltv_expiry: u32,
 }
 
@@ -326,12 +326,11 @@ pub(super) struct ChannelHolder<Signer: Sign> {
        /// guarantees are made about the existence of a channel with the short id here, nor the short
        /// ids in the PendingHTLCInfo!
        pub(super) forward_htlcs: HashMap<u64, Vec<HTLCForwardInfo>>,
-       /// (payment_hash, payment_secret) -> Vec<HTLCs> for tracking HTLCs that
-       /// were to us and can be failed/claimed by the user
+       /// Map from payment hash to any HTLCs which are to us and can be failed/claimed by the user.
        /// Note that while this is held in the same mutex as the channels themselves, no consistency
        /// guarantees are made about the channels given here actually existing anymore by the time you
        /// go to read them!
-       claimable_htlcs: HashMap<(PaymentHash, Option<PaymentSecret>), Vec<ClaimableHTLC>>,
+       claimable_htlcs: HashMap<PaymentHash, Vec<ClaimableHTLC>>,
        /// Messages to send to peers - pushed to in the same lock that they are generated in (except
        /// for broadcast messages, where ordering isn't as strict).
        pub(super) pending_msg_events: Vec<MessageSendEvent>,
@@ -352,6 +351,24 @@ struct PeerState {
        latest_features: InitFeatures,
 }
 
+/// Stores a PaymentSecret and any other data we may need to validate an inbound payment is
+/// actually ours and not some duplicate HTLC sent to us by a node along the route.
+///
+/// For users who don't want to bother doing their own payment preimage storage, we also store that
+/// here.
+struct PendingInboundPayment {
+       /// The payment secret that the sender must use for us to accept this payment
+       payment_secret: PaymentSecret,
+       /// Time at which this HTLC expires - blocks with a header time above this value will result in
+       /// this payment being removed.
+       expiry_time: u64,
+       /// Arbitrary identifier the user specifies (or not)
+       user_payment_id: u64,
+       // Other required attributes of the payment, optionally enforced:
+       payment_preimage: Option<PaymentPreimage>,
+       min_value_msat: Option<u64>,
+}
+
 /// SimpleArcChannelManager is useful when you need a ChannelManager with a static lifetime, e.g.
 /// when you're using lightning-net-tokio (since tokio::spawn requires parameters with static
 /// lifetimes). Other times you can afford a reference, which is more efficient, in which case
@@ -430,6 +447,14 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
        pub(super) channel_state: Mutex<ChannelHolder<Signer>>,
        #[cfg(not(any(test, feature = "_test_utils")))]
        channel_state: Mutex<ChannelHolder<Signer>>,
+
+       /// Storage for PaymentSecrets and any requirements on future inbound payments before we will
+       /// expose them to users via a PaymentReceived event. HTLCs which do not meet the requirements
+       /// here are failed when we process them as pending-forwardable-HTLCs, and entries are removed
+       /// after we generate a PaymentReceived upon receipt of all MPP parts.
+       /// Locked *after* channel_state.
+       pending_inbound_payments: Mutex<HashMap<PaymentHash, PendingInboundPayment>>,
+
        our_network_key: SecretKey,
        our_network_pubkey: PublicKey,
 
@@ -437,6 +462,11 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
        /// value increases strictly since we don't assume access to a time source.
        last_node_announcement_serial: AtomicUsize,
 
+       /// The highest block timestamp we've seen, which is usually a good guess at the current time.
+       /// Assuming most miners are generating blocks with reasonable timestamps, this shouldn't be
+       /// very far in the past, and can only ever be up to two hours in the future.
+       highest_seen_timestamp: AtomicUsize,
+
        /// The bulk of our storage will eventually be here (channels and message queues and the like).
        /// If we are connected to a peer we always at least have an entry here, even if no channels
        /// are currently open with that peer.
@@ -478,6 +508,7 @@ pub struct ChainParameters {
 }
 
 /// The best known block as identified by its hash and height.
+#[derive(Clone, Copy)]
 pub struct BestBlock {
        block_hash: BlockHash,
        height: u32,
@@ -851,11 +882,14 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                claimable_htlcs: HashMap::new(),
                                pending_msg_events: Vec::new(),
                        }),
+                       pending_inbound_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()),
                        secp_ctx,
 
                        last_node_announcement_serial: AtomicUsize::new(0),
+                       highest_seen_timestamp: AtomicUsize::new(0),
 
                        per_peer_state: RwLock::new(HashMap::new()),
 
@@ -1213,6 +1247,10 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        msgs::OnionHopDataFormat::FinalNode { payment_data } => payment_data,
                                };
 
+                               if payment_data.is_none() {
+                                       return_err!("We require payment_secrets", 0x4000|0x2000|3, &[0;0]);
+                               }
+
                                // 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
@@ -1220,7 +1258,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
                                PendingHTLCStatus::Forward(PendingHTLCInfo {
                                        routing: PendingHTLCRouting::Receive {
-                                               payment_data,
+                                               payment_data: payment_data.unwrap(),
                                                incoming_cltv_expiry: msg.cltv_expiry,
                                        },
                                        payment_hash: msg.payment_hash.clone(),
@@ -1562,61 +1600,14 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                }
        }
 
-       /// Call this upon creation of a funding transaction for the given channel.
-       ///
-       /// Returns an [`APIError::APIMisuseError`] if the funding_transaction spent non-SegWit outputs
-       /// or if no output was found which matches the parameters in [`Event::FundingGenerationReady`].
-       ///
-       /// Panics if a funding transaction has already been provided for this channel.
-       ///
-       /// May panic if the output found in the funding transaction is duplicative with some other
-       /// channel (note that this should be trivially prevented by using unique funding transaction
-       /// keys per-channel).
-       ///
-       /// Do NOT broadcast the funding transaction yourself. When we have safely received our
-       /// counterparty's signature the funding transaction will automatically be broadcast via the
-       /// [`BroadcasterInterface`] provided when this `ChannelManager` was constructed.
-       ///
-       /// Note that this includes RBF or similar transaction replacement strategies - lightning does
-       /// not currently support replacing a funding transaction on an existing channel. Instead,
-       /// create a new channel with a conflicting funding transaction.
-       pub fn funding_transaction_generated(&self, temporary_channel_id: &[u8; 32], funding_transaction: Transaction) -> Result<(), APIError> {
-               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
-
-               for inp in funding_transaction.input.iter() {
-                       if inp.witness.is_empty() {
-                               return Err(APIError::APIMisuseError {
-                                       err: "Funding transaction must be fully signed and spend Segwit outputs".to_owned()
-                               });
-                       }
-               }
-
+       /// Handles the generation of a funding transaction, optionally (for tests) with a function
+       /// which checks the correctness of the funding transaction given the associated channel.
+       fn funding_transaction_generated_intern<FundingOutput: Fn(&Channel<Signer>, &Transaction) -> Result<OutPoint, APIError>>
+                       (&self, temporary_channel_id: &[u8; 32], funding_transaction: Transaction, find_funding_output: FundingOutput) -> Result<(), APIError> {
                let (chan, msg) = {
                        let (res, chan) = match self.channel_state.lock().unwrap().by_id.remove(temporary_channel_id) {
                                Some(mut chan) => {
-                                       let mut output_index = None;
-                                       let expected_spk = chan.get_funding_redeemscript().to_v0_p2wsh();
-                                       for (idx, outp) in funding_transaction.output.iter().enumerate() {
-                                               if outp.script_pubkey == expected_spk && outp.value == chan.get_value_satoshis() {
-                                                       if output_index.is_some() {
-                                                               return Err(APIError::APIMisuseError {
-                                                                       err: "Multiple outputs matched the expected script and value".to_owned()
-                                                               });
-                                                       }
-                                                       if idx > u16::max_value() as usize {
-                                                               return Err(APIError::APIMisuseError {
-                                                                       err: "Transaction had more than 2^16 outputs, which is not supported".to_owned()
-                                                               });
-                                                       }
-                                                       output_index = Some(idx as u16);
-                                               }
-                                       }
-                                       if output_index.is_none() {
-                                               return Err(APIError::APIMisuseError {
-                                                       err: "No output matched the script_pubkey and value in the FundingGenerationReady event".to_owned()
-                                               });
-                                       }
-                                       let funding_txo = OutPoint { txid: funding_transaction.txid(), index: output_index.unwrap() };
+                                       let funding_txo = find_funding_output(&chan, &funding_transaction)?;
 
                                        (chan.get_outbound_funding_created(funding_transaction, funding_txo, &self.logger)
                                                .map_err(|e| if let ChannelError::Close(msg) = e {
@@ -1652,6 +1643,68 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                Ok(())
        }
 
+       #[cfg(test)]
+       pub(crate) fn funding_transaction_generated_unchecked(&self, temporary_channel_id: &[u8; 32], funding_transaction: Transaction, output_index: u16) -> Result<(), APIError> {
+               self.funding_transaction_generated_intern(temporary_channel_id, funding_transaction, |_, tx| {
+                       Ok(OutPoint { txid: tx.txid(), index: output_index })
+               })
+       }
+
+       /// Call this upon creation of a funding transaction for the given channel.
+       ///
+       /// Returns an [`APIError::APIMisuseError`] if the funding_transaction spent non-SegWit outputs
+       /// or if no output was found which matches the parameters in [`Event::FundingGenerationReady`].
+       ///
+       /// Panics if a funding transaction has already been provided for this channel.
+       ///
+       /// May panic if the output found in the funding transaction is duplicative with some other
+       /// channel (note that this should be trivially prevented by using unique funding transaction
+       /// keys per-channel).
+       ///
+       /// Do NOT broadcast the funding transaction yourself. When we have safely received our
+       /// counterparty's signature the funding transaction will automatically be broadcast via the
+       /// [`BroadcasterInterface`] provided when this `ChannelManager` was constructed.
+       ///
+       /// Note that this includes RBF or similar transaction replacement strategies - lightning does
+       /// not currently support replacing a funding transaction on an existing channel. Instead,
+       /// create a new channel with a conflicting funding transaction.
+       pub fn funding_transaction_generated(&self, temporary_channel_id: &[u8; 32], funding_transaction: Transaction) -> Result<(), APIError> {
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+
+               for inp in funding_transaction.input.iter() {
+                       if inp.witness.is_empty() {
+                               return Err(APIError::APIMisuseError {
+                                       err: "Funding transaction must be fully signed and spend Segwit outputs".to_owned()
+                               });
+                       }
+               }
+               self.funding_transaction_generated_intern(temporary_channel_id, funding_transaction, |chan, tx| {
+                       let mut output_index = None;
+                       let expected_spk = chan.get_funding_redeemscript().to_v0_p2wsh();
+                       for (idx, outp) in tx.output.iter().enumerate() {
+                               if outp.script_pubkey == expected_spk && outp.value == chan.get_value_satoshis() {
+                                       if output_index.is_some() {
+                                               return Err(APIError::APIMisuseError {
+                                                       err: "Multiple outputs matched the expected script and value".to_owned()
+                                               });
+                                       }
+                                       if idx > u16::max_value() as usize {
+                                               return Err(APIError::APIMisuseError {
+                                                       err: "Transaction had more than 2^16 outputs, which is not supported".to_owned()
+                                               });
+                                       }
+                                       output_index = Some(idx as u16);
+                               }
+                       }
+                       if output_index.is_none() {
+                               return Err(APIError::APIMisuseError {
+                                       err: "No output matched the script_pubkey and value in the FundingGenerationReady event".to_owned()
+                               });
+                       }
+                       Ok(OutPoint { txid: tx.txid(), index: output_index.unwrap() })
+               })
+       }
+
        fn get_announcement_sigs(&self, chan: &Channel<Signer>) -> Option<msgs::AnnouncementSignatures> {
                if !chan.should_announce() {
                        log_trace!(self.logger, "Can't send announcement_signatures for private channel {}", log_bytes!(chan.channel_id()));
@@ -1899,61 +1952,94 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                                        routing: PendingHTLCRouting::Receive { payment_data, incoming_cltv_expiry },
                                                                        incoming_shared_secret, payment_hash, amt_to_forward, .. },
                                                                        prev_funding_outpoint } => {
-                                                               let prev_hop = HTLCPreviousHopData {
-                                                                       short_channel_id: prev_short_channel_id,
-                                                                       outpoint: prev_funding_outpoint,
-                                                                       htlc_id: prev_htlc_id,
-                                                                       incoming_packet_shared_secret: incoming_shared_secret,
-                                                               };
-
-                                                               let mut total_value = 0;
-                                                               let payment_secret_opt =
-                                                                       if let &Some(ref data) = &payment_data { Some(data.payment_secret.clone()) } else { None };
-                                                               let htlcs = channel_state.claimable_htlcs.entry((payment_hash, payment_secret_opt))
-                                                                       .or_insert(Vec::new());
-                                                               htlcs.push(ClaimableHTLC {
-                                                                       prev_hop,
+                                                               let claimable_htlc = ClaimableHTLC {
+                                                                       prev_hop: HTLCPreviousHopData {
+                                                                               short_channel_id: prev_short_channel_id,
+                                                                               outpoint: prev_funding_outpoint,
+                                                                               htlc_id: prev_htlc_id,
+                                                                               incoming_packet_shared_secret: incoming_shared_secret,
+                                                                       },
                                                                        value: amt_to_forward,
                                                                        payment_data: payment_data.clone(),
                                                                        cltv_expiry: incoming_cltv_expiry,
-                                                               });
-                                                               if let &Some(ref data) = &payment_data {
-                                                                       for htlc in htlcs.iter() {
-                                                                               total_value += htlc.value;
-                                                                               if htlc.payment_data.as_ref().unwrap().total_msat != data.total_msat {
-                                                                                       total_value = msgs::MAX_VALUE_MSAT;
-                                                                               }
-                                                                               if total_value >= msgs::MAX_VALUE_MSAT { break; }
-                                                                       }
-                                                                       if total_value >= msgs::MAX_VALUE_MSAT || total_value > data.total_msat  {
-                                                                               for htlc in htlcs.iter() {
-                                                                                       let mut htlc_msat_height_data = byte_utils::be64_to_array(htlc.value).to_vec();
-                                                                                       htlc_msat_height_data.extend_from_slice(
-                                                                                               &byte_utils::be32_to_array(self.best_block.read().unwrap().height()),
-                                                                                       );
-                                                                                       failed_forwards.push((HTLCSource::PreviousHopData(HTLCPreviousHopData {
-                                                                                                       short_channel_id: htlc.prev_hop.short_channel_id,
-                                                                                                       outpoint: prev_funding_outpoint,
-                                                                                                       htlc_id: htlc.prev_hop.htlc_id,
-                                                                                                       incoming_packet_shared_secret: htlc.prev_hop.incoming_packet_shared_secret,
-                                                                                               }), payment_hash,
-                                                                                               HTLCFailReason::Reason { failure_code: 0x4000 | 15, data: htlc_msat_height_data }
-                                                                                       ));
-                                                                               }
-                                                                       } else if total_value == data.total_msat {
-                                                                               new_events.push(events::Event::PaymentReceived {
-                                                                                       payment_hash,
-                                                                                       payment_secret: Some(data.payment_secret),
-                                                                                       amt: total_value,
-                                                                               });
+                                                               };
+
+                                                               macro_rules! fail_htlc {
+                                                                       ($htlc: expr) => {
+                                                                               let mut htlc_msat_height_data = byte_utils::be64_to_array($htlc.value).to_vec();
+                                                                               htlc_msat_height_data.extend_from_slice(
+                                                                                       &byte_utils::be32_to_array(self.best_block.read().unwrap().height()),
+                                                                               );
+                                                                               failed_forwards.push((HTLCSource::PreviousHopData(HTLCPreviousHopData {
+                                                                                               short_channel_id: $htlc.prev_hop.short_channel_id,
+                                                                                               outpoint: prev_funding_outpoint,
+                                                                                               htlc_id: $htlc.prev_hop.htlc_id,
+                                                                                               incoming_packet_shared_secret: $htlc.prev_hop.incoming_packet_shared_secret,
+                                                                                       }), payment_hash,
+                                                                                       HTLCFailReason::Reason { failure_code: 0x4000 | 15, data: htlc_msat_height_data }
+                                                                               ));
                                                                        }
-                                                               } else {
-                                                                       new_events.push(events::Event::PaymentReceived {
-                                                                               payment_hash,
-                                                                               payment_secret: None,
-                                                                               amt: amt_to_forward,
-                                                                       });
                                                                }
+
+                                                               // Check that the payment hash and secret are known. Note that we
+                                                               // MUST take care to handle the "unknown payment hash" and
+                                                               // "incorrect payment secret" cases here identically or we'd expose
+                                                               // that we are the ultimate recipient of the given payment hash.
+                                                               // Further, we must not expose whether we have any other HTLCs
+                                                               // associated with the same payment_hash pending or not.
+                                                               let mut payment_secrets = self.pending_inbound_payments.lock().unwrap();
+                                                               match payment_secrets.entry(payment_hash) {
+                                                                       hash_map::Entry::Vacant(_) => {
+                                                                               log_trace!(self.logger, "Failing new HTLC with payment_hash {} as we didn't have a corresponding inbound payment.", log_bytes!(payment_hash.0));
+                                                                               fail_htlc!(claimable_htlc);
+                                                                       },
+                                                                       hash_map::Entry::Occupied(inbound_payment) => {
+                                                                               if inbound_payment.get().payment_secret != payment_data.payment_secret {
+                                                                                       log_trace!(self.logger, "Failing new HTLC with payment_hash {} as it didn't match our expected payment secret.", log_bytes!(payment_hash.0));
+                                                                                       fail_htlc!(claimable_htlc);
+                                                                               } else if inbound_payment.get().min_value_msat.is_some() && payment_data.total_msat < inbound_payment.get().min_value_msat.unwrap() {
+                                                                                       log_trace!(self.logger, "Failing new HTLC with payment_hash {} as it didn't match our minimum value (had {}, needed {}).",
+                                                                                               log_bytes!(payment_hash.0), payment_data.total_msat, inbound_payment.get().min_value_msat.unwrap());
+                                                                                       fail_htlc!(claimable_htlc);
+                                                                               } else {
+                                                                                       let mut total_value = 0;
+                                                                                       let htlcs = channel_state.claimable_htlcs.entry(payment_hash)
+                                                                                               .or_insert(Vec::new());
+                                                                                       htlcs.push(claimable_htlc);
+                                                                                       for htlc in htlcs.iter() {
+                                                                                               total_value += htlc.value;
+                                                                                               if htlc.payment_data.total_msat != payment_data.total_msat {
+                                                                                                       log_trace!(self.logger, "Failing HTLCs with payment_hash {} as the HTLCs had inconsistent total values (eg {} and {})",
+                                                                                                               log_bytes!(payment_hash.0), payment_data.total_msat, htlc.payment_data.total_msat);
+                                                                                                       total_value = msgs::MAX_VALUE_MSAT;
+                                                                                               }
+                                                                                               if total_value >= msgs::MAX_VALUE_MSAT { break; }
+                                                                                       }
+                                                                                       if total_value >= msgs::MAX_VALUE_MSAT || total_value > payment_data.total_msat {
+                                                                                               log_trace!(self.logger, "Failing HTLCs with payment_hash {} as the total value {} ran over expected value {} (or HTLCs were inconsistent)",
+                                                                                                       log_bytes!(payment_hash.0), total_value, payment_data.total_msat);
+                                                                                               for htlc in htlcs.iter() {
+                                                                                                       fail_htlc!(htlc);
+                                                                                               }
+                                                                                       } else if total_value == payment_data.total_msat {
+                                                                                               new_events.push(events::Event::PaymentReceived {
+                                                                                                       payment_hash,
+                                                                                                       payment_secret: payment_data.payment_secret,
+                                                                                                       amt: total_value,
+                                                                                                       user_payment_id: inbound_payment.get().user_payment_id,
+                                                                                               });
+                                                                                               // Only ever generate at most one PaymentReceived
+                                                                                               // per registered payment_hash, even if it isn't
+                                                                                               // claimed.
+                                                                                               inbound_payment.remove_entry();
+                                                                                       } else {
+                                                                                               // Nothing to do - we haven't reached the total
+                                                                                               // payment value yet, wait until we receive more
+                                                                                               // MPP parts.
+                                                                                       }
+                                                                               }
+                                                                       },
+                                                               };
                                                        },
                                                        HTLCForwardInfo::AddHTLC { .. } => {
                                                                panic!("short_channel_id == 0 should imply any pending_forward entries are of type Receive");
@@ -2039,11 +2125,11 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        /// along the path (including in our own channel on which we received it).
        /// Returns false if no payment was found to fail backwards, true if the process of failing the
        /// HTLC backwards has been started.
-       pub fn fail_htlc_backwards(&self, payment_hash: &PaymentHash, payment_secret: &Option<PaymentSecret>) -> bool {
+       pub fn fail_htlc_backwards(&self, payment_hash: &PaymentHash) -> bool {
                let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
 
                let mut channel_state = Some(self.channel_state.lock().unwrap());
-               let removed_source = channel_state.as_mut().unwrap().claimable_htlcs.remove(&(*payment_hash, *payment_secret));
+               let removed_source = channel_state.as_mut().unwrap().claimable_htlcs.remove(payment_hash);
                if let Some(mut sources) = removed_source {
                        for htlc in sources.drain(..) {
                                if channel_state.is_none() { channel_state = Some(self.channel_state.lock().unwrap()); }
@@ -2208,24 +2294,22 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        /// generating message events for the net layer to claim the payment, if possible. Thus, you
        /// should probably kick the net layer to go send messages if this returns true!
        ///
-       /// You must specify the expected amounts for this HTLC, and we will only claim HTLCs
-       /// available within a few percent of the expected amount. This is critical for several
-       /// reasons : a) it avoids providing senders with `proof-of-payment` (in the form of the
-       /// payment_preimage without having provided the full value and b) it avoids certain
-       /// privacy-breaking recipient-probing attacks which may reveal payment activity to
-       /// motivated attackers.
-       ///
-       /// Note that the privacy concerns in (b) are not relevant in payments with a payment_secret
-       /// set. Thus, for such payments we will claim any payments which do not under-pay.
+       /// Note that if you did not set an `amount_msat` when calling [`create_inbound_payment`] or
+       /// [`create_inbound_payment_for_hash`] you must check that the amount in the `PaymentReceived`
+       /// event matches your expectation. If you fail to do so and call this method, you may provide
+       /// the sender "proof-of-payment" when they did not fulfill the full expected payment.
        ///
        /// May panic if called except in response to a PaymentReceived event.
-       pub fn claim_funds(&self, payment_preimage: PaymentPreimage, payment_secret: &Option<PaymentSecret>, expected_amount: u64) -> bool {
+       ///
+       /// [`create_inbound_payment`]: Self::create_inbound_payment
+       /// [`create_inbound_payment_for_hash`]: Self::create_inbound_payment_for_hash
+       pub fn claim_funds(&self, payment_preimage: PaymentPreimage) -> bool {
                let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 
                let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
 
                let mut channel_state = Some(self.channel_state.lock().unwrap());
-               let removed_source = channel_state.as_mut().unwrap().claimable_htlcs.remove(&(payment_hash, *payment_secret));
+               let removed_source = channel_state.as_mut().unwrap().claimable_htlcs.remove(&payment_hash);
                if let Some(mut sources) = removed_source {
                        assert!(!sources.is_empty());
 
@@ -2240,27 +2324,19 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        // we got all the HTLCs and then a channel closed while we were waiting for the user to
                        // provide the preimage, so worrying too much about the optimal handling isn't worth
                        // it.
-
-                       let (is_mpp, mut valid_mpp) = if let &Some(ref data) = &sources[0].payment_data {
-                               assert!(payment_secret.is_some());
-                               (true, data.total_msat >= expected_amount)
-                       } else {
-                               assert!(payment_secret.is_none());
-                               (false, false)
-                       };
-
+                       let mut valid_mpp = true;
                        for htlc in sources.iter() {
-                               if !is_mpp || !valid_mpp { break; }
                                if let None = channel_state.as_ref().unwrap().short_to_id.get(&htlc.prev_hop.short_channel_id) {
                                        valid_mpp = false;
+                                       break;
                                }
                        }
 
                        let mut errs = Vec::new();
                        let mut claimed_any_htlcs = false;
                        for htlc in sources.drain(..) {
-                               if channel_state.is_none() { channel_state = Some(self.channel_state.lock().unwrap()); }
-                               if (is_mpp && !valid_mpp) || (!is_mpp && (htlc.value < expected_amount || htlc.value > expected_amount * 2)) {
+                               if !valid_mpp {
+                                       if channel_state.is_none() { channel_state = Some(self.channel_state.lock().unwrap()); }
                                        let mut htlc_msat_height_data = byte_utils::be64_to_array(htlc.value).to_vec();
                                        htlc_msat_height_data.extend_from_slice(&byte_utils::be32_to_array(
                                                        self.best_block.read().unwrap().height()));
@@ -2277,10 +2353,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                                claimed_any_htlcs = true;
                                                        } else { errs.push(e); }
                                                },
-                                               Err(None) if is_mpp => unreachable!("We already checked for channel existence, we can't fail here!"),
-                                               Err(None) => {
-                                                       log_warn!(self.logger, "Channel we expected to claim an HTLC from was closed.");
-                                               },
+                                               Err(None) => unreachable!("We already checked for channel existence, we can't fail here!"),
                                                Ok(()) => claimed_any_htlcs = true,
                                        }
                                }
@@ -2548,7 +2621,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
        fn internal_funding_created(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingCreated) -> Result<(), MsgHandleErrInternal> {
                let ((funding_msg, monitor), mut chan) = {
-                       let last_block_hash = self.best_block.read().unwrap().block_hash();
+                       let best_block = *self.best_block.read().unwrap();
                        let mut channel_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_lock;
                        match channel_state.by_id.entry(msg.temporary_channel_id.clone()) {
@@ -2556,7 +2629,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        if chan.get().get_counterparty_node_id() != *counterparty_node_id {
                                                return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), msg.temporary_channel_id));
                                        }
-                                       (try_chan_entry!(self, chan.get_mut().funding_created(msg, last_block_hash, &self.logger), channel_state, chan), chan.remove())
+                                       (try_chan_entry!(self, chan.get_mut().funding_created(msg, best_block, &self.logger), channel_state, chan), chan.remove())
                                },
                                hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close("Failed to find corresponding channel".to_owned(), msg.temporary_channel_id))
                        }
@@ -2605,7 +2678,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
        fn internal_funding_signed(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingSigned) -> Result<(), MsgHandleErrInternal> {
                let funding_tx = {
-                       let last_block_hash = self.best_block.read().unwrap().block_hash();
+                       let best_block = *self.best_block.read().unwrap();
                        let mut channel_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_lock;
                        match channel_state.by_id.entry(msg.channel_id) {
@@ -2613,7 +2686,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        if chan.get().get_counterparty_node_id() != *counterparty_node_id {
                                                return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), msg.channel_id));
                                        }
-                                       let (monitor, funding_tx) = match chan.get_mut().funding_signed(&msg, last_block_hash, &self.logger) {
+                                       let (monitor, funding_tx) = match chan.get_mut().funding_signed(&msg, best_block, &self.logger) {
                                                Ok(update) => update,
                                                Err(e) => try_chan_entry!(self, Err(e), channel_state, chan),
                                        };
@@ -3304,6 +3377,92 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        self.finish_force_close_channel(failure);
                }
        }
+
+       fn set_payment_hash_secret_map(&self, payment_hash: PaymentHash, payment_preimage: Option<PaymentPreimage>, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32, user_payment_id: u64) -> Result<PaymentSecret, APIError> {
+               assert!(invoice_expiry_delta_secs <= 60*60*24*365); // Sadly bitcoin timestamps are u32s, so panic before 2106
+
+               let payment_secret = PaymentSecret(self.keys_manager.get_secure_random_bytes());
+
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+               let mut payment_secrets = self.pending_inbound_payments.lock().unwrap();
+               match payment_secrets.entry(payment_hash) {
+                       hash_map::Entry::Vacant(e) => {
+                               e.insert(PendingInboundPayment {
+                                       payment_secret, min_value_msat, user_payment_id, payment_preimage,
+                                       // We assume that highest_seen_timestamp is pretty close to the current time -
+                                       // its updated when we receive a new block with the maximum time we've seen in
+                                       // a header. It should never be more than two hours in the future.
+                                       // Thus, we add two hours here as a buffer to ensure we absolutely
+                                       // never fail a payment too early.
+                                       // Note that we assume that received blocks have reasonably up-to-date
+                                       // timestamps.
+                                       expiry_time: self.highest_seen_timestamp.load(Ordering::Acquire) as u64 + invoice_expiry_delta_secs as u64 + 7200,
+                               });
+                       },
+                       hash_map::Entry::Occupied(_) => return Err(APIError::APIMisuseError { err: "Duplicate payment hash".to_owned() }),
+               }
+               Ok(payment_secret)
+       }
+
+       /// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
+       /// to pay us.
+       ///
+       /// This differs from [`create_inbound_payment_for_hash`] only in that it generates the
+       /// [`PaymentHash`] and [`PaymentPreimage`] for you, returning the first and storing the second.
+       ///
+       /// See [`create_inbound_payment_for_hash`] for detailed documentation on behavior and requirements.
+       ///
+       /// [`create_inbound_payment_for_hash`]: Self::create_inbound_payment_for_hash
+       pub fn create_inbound_payment(&self, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32, user_payment_id: u64) -> (PaymentHash, PaymentSecret) {
+               let payment_preimage = PaymentPreimage(self.keys_manager.get_secure_random_bytes());
+               let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
+
+               (payment_hash,
+                       self.set_payment_hash_secret_map(payment_hash, Some(payment_preimage), min_value_msat, invoice_expiry_delta_secs, user_payment_id)
+                               .expect("RNG Generated Duplicate PaymentHash"))
+       }
+
+       /// Gets a [`PaymentSecret`] for a given [`PaymentHash`], for which the payment preimage is
+       /// stored external to LDK.
+       ///
+       /// A [`PaymentReceived`] event will only be generated if the [`PaymentSecret`] matches a
+       /// payment secret fetched via this method or [`create_inbound_payment`], and which is at least
+       /// the `min_value_msat` provided here, if one is provided.
+       ///
+       /// The [`PaymentHash`] (and corresponding [`PaymentPreimage`]) must be globally unique. This
+       /// method may return an Err if another payment with the same payment_hash is still pending.
+       ///
+       /// `user_payment_id` will be provided back in [`PaymentReceived::user_payment_id`] events to
+       /// allow tracking of which events correspond with which calls to this and
+       /// [`create_inbound_payment`]. `user_payment_id` has no meaning inside of LDK, it is simply
+       /// copied to events and otherwise ignored. It may be used to correlate PaymentReceived events
+       /// with invoice metadata stored elsewhere.
+       ///
+       /// `min_value_msat` should be set if the invoice being generated contains a value. Any payment
+       /// received for the returned [`PaymentHash`] will be required to be at least `min_value_msat`
+       /// before a [`PaymentReceived`] event will be generated, ensuring that we do not provide the
+       /// sender "proof-of-payment" unless they have paid the required amount.
+       ///
+       /// `invoice_expiry_delta_secs` describes the number of seconds that the invoice is valid for
+       /// in excess of the current time. This should roughly match the expiry time set in the invoice.
+       /// After this many seconds, we will remove the inbound payment, resulting in any attempts to
+       /// pay the invoice failing. The BOLT spec suggests 7,200 secs as a default validity time for
+       /// invoices when no timeout is set.
+       ///
+       /// Note that we use block header time to time-out pending inbound payments (with some margin
+       /// to compensate for the inaccuracy of block header timestamps). Thus, in practice we will
+       /// accept a payment and generate a [`PaymentReceived`] event for some time after the expiry.
+       /// If you need exact expiry semantics, you should enforce them upon receipt of
+       /// [`PaymentReceived`].
+       ///
+       /// May panic if `invoice_expiry_delta_secs` is greater than one year.
+       ///
+       /// [`create_inbound_payment`]: Self::create_inbound_payment
+       /// [`PaymentReceived`]: events::Event::PaymentReceived
+       /// [`PaymentReceived::user_payment_id`]: events::Event::PaymentReceived::user_payment_id
+       pub fn create_inbound_payment_for_hash(&self, payment_hash: PaymentHash, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32, user_payment_id: u64) -> Result<PaymentSecret, APIError> {
+               self.set_payment_hash_secret_map(payment_hash, None, min_value_msat, invoice_expiry_delta_secs, user_payment_id)
+       }
 }
 
 impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> MessageSendEventsProvider for ChannelManager<Signer, M, T, K, F, L>
@@ -3362,8 +3521,8 @@ where
                }
 
                let txdata: Vec<_> = block.txdata.iter().enumerate().collect();
-               self.transactions_confirmed(&block.header, height, &txdata);
-               self.update_best_block(&block.header, height);
+               self.transactions_confirmed(&block.header, &txdata, height);
+               self.best_block_updated(&block.header, height);
        }
 
        fn block_disconnected(&self, header: &BlockHeader, height: u32) {
@@ -3378,16 +3537,94 @@ where
                        *best_block = BestBlock::new(header.prev_blockhash, new_height)
                }
 
-               self.do_chain_event(Some(new_height), |channel| channel.update_best_block(new_height, header.time));
+               self.do_chain_event(Some(new_height), |channel| channel.best_block_updated(new_height, header.time));
+       }
+}
+
+impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> chain::Confirm for ChannelManager<Signer, M, T, K, F, L>
+where
+       M::Target: chain::Watch<Signer>,
+       T::Target: BroadcasterInterface,
+       K::Target: KeysInterface<Signer = Signer>,
+       F::Target: FeeEstimator,
+       L::Target: Logger,
+{
+       fn transactions_confirmed(&self, header: &BlockHeader, txdata: &TransactionData, height: u32) {
+               // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
+               // during initialization prior to the chain_monitor being fully configured in some cases.
+               // See the docs for `ChannelManagerReadArgs` for more.
+
+               let block_hash = header.block_hash();
+               log_trace!(self.logger, "{} transactions included in block {} at height {} provided", txdata.len(), block_hash, height);
+
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+               self.do_chain_event(Some(height), |channel| channel.transactions_confirmed(&block_hash, height, txdata, &self.logger).map(|a| (a, Vec::new())));
+       }
+
+       fn best_block_updated(&self, header: &BlockHeader, height: u32) {
+               // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
+               // during initialization prior to the chain_monitor being fully configured in some cases.
+               // See the docs for `ChannelManagerReadArgs` for more.
+
+               let block_hash = header.block_hash();
+               log_trace!(self.logger, "New best block: {} at height {}", block_hash, height);
+
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+
+               *self.best_block.write().unwrap() = BestBlock::new(block_hash, height);
+
+               self.do_chain_event(Some(height), |channel| channel.best_block_updated(height, header.time));
+
+               macro_rules! max_time {
+                       ($timestamp: expr) => {
+                               loop {
+                                       // Update $timestamp to be the max of its current value and the block
+                                       // timestamp. This should keep us close to the current time without relying on
+                                       // having an explicit local time source.
+                                       // Just in case we end up in a race, we loop until we either successfully
+                                       // update $timestamp or decide we don't need to.
+                                       let old_serial = $timestamp.load(Ordering::Acquire);
+                                       if old_serial >= header.time as usize { break; }
+                                       if $timestamp.compare_exchange(old_serial, header.time as usize, Ordering::AcqRel, Ordering::Relaxed).is_ok() {
+                                               break;
+                                       }
+                               }
+                       }
+               }
+               max_time!(self.last_node_announcement_serial);
+               max_time!(self.highest_seen_timestamp);
+       }
+
+       fn get_relevant_txids(&self) -> Vec<Txid> {
+               let channel_state = self.channel_state.lock().unwrap();
+               let mut res = Vec::with_capacity(channel_state.short_to_id.len());
+               for chan in channel_state.by_id.values() {
+                       if let Some(funding_txo) = chan.get_funding_txo() {
+                               res.push(funding_txo.txid);
+                       }
+               }
+               res
+       }
+
+       fn transaction_unconfirmed(&self, txid: &Txid) {
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+               self.do_chain_event(None, |channel| {
+                       if let Some(funding_txo) = channel.get_funding_txo() {
+                               if funding_txo.txid == *txid {
+                                       channel.funding_transaction_unconfirmed().map(|_| (None, Vec::new()))
+                               } else { Ok((None, Vec::new())) }
+                       } else { Ok((None, Vec::new())) }
+               });
        }
 }
 
 impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelManager<Signer, M, T, K, F, L>
-       where M::Target: chain::Watch<Signer>,
-        T::Target: BroadcasterInterface,
-        K::Target: KeysInterface<Signer = Signer>,
-        F::Target: FeeEstimator,
-        L::Target: Logger,
+where
+       M::Target: chain::Watch<Signer>,
+       T::Target: BroadcasterInterface,
+       K::Target: KeysInterface<Signer = Signer>,
+       F::Target: FeeEstimator,
+       L::Target: Logger,
 {
        /// Calls a function which handles an on-chain event (blocks dis/connected, transactions
        /// un/confirmed, etc) on each channel, handling any resulting errors or messages generated by
@@ -3453,7 +3690,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        });
 
                        if let Some(height) = height_opt {
-                               channel_state.claimable_htlcs.retain(|&(ref payment_hash, _), htlcs| {
+                               channel_state.claimable_htlcs.retain(|payment_hash, htlcs| {
                                        htlcs.retain(|htlc| {
                                                // If height is approaching the number of blocks we think it takes us to get
                                                // our commitment transaction confirmed before the HTLC expires, plus the
@@ -3481,131 +3718,6 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                }
        }
 
-       /// Updates channel state to take note of transactions which were confirmed in the given block
-       /// at the given height.
-       ///
-       /// Note that you must still call (or have called) [`update_best_block`] with the block
-       /// information which is included here.
-       ///
-       /// This method may be called before or after [`update_best_block`] for a given block's
-       /// transaction data and may be called multiple times with additional transaction data for a
-       /// given block.
-       ///
-       /// This method may be called for a previous block after an [`update_best_block`] call has
-       /// been made for a later block, however it must *not* be called with transaction data from a
-       /// block which is no longer in the best chain (ie where [`update_best_block`] has already
-       /// been informed about a blockchain reorganization which no longer includes the block which
-       /// corresponds to `header`).
-       ///
-       /// [`update_best_block`]: `Self::update_best_block`
-       pub fn transactions_confirmed(&self, header: &BlockHeader, height: u32, txdata: &TransactionData) {
-               // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
-               // during initialization prior to the chain_monitor being fully configured in some cases.
-               // See the docs for `ChannelManagerReadArgs` for more.
-
-               let block_hash = header.block_hash();
-               log_trace!(self.logger, "{} transactions included in block {} at height {} provided", txdata.len(), block_hash, height);
-
-               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
-               self.do_chain_event(Some(height), |channel| channel.transactions_confirmed(&block_hash, height, txdata, &self.logger).map(|a| (a, Vec::new())));
-       }
-
-       /// Updates channel state with the current best blockchain tip. You should attempt to call this
-       /// quickly after a new block becomes available, however if multiple new blocks become
-       /// available at the same time, only a single `update_best_block()` call needs to be made.
-       ///
-       /// This method should also be called immediately after any block disconnections, once at the
-       /// reorganization fork point, and once with the new chain tip. Calling this method at the
-       /// blockchain reorganization fork point ensures we learn when a funding transaction which was
-       /// previously confirmed is reorganized out of the blockchain, ensuring we do not continue to
-       /// accept payments which cannot be enforced on-chain.
-       ///
-       /// In both the block-connection and block-disconnection case, this method may be called either
-       /// once per block connected or disconnected, or simply at the fork point and new tip(s),
-       /// skipping any intermediary blocks.
-       pub fn update_best_block(&self, header: &BlockHeader, height: u32) {
-               // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
-               // during initialization prior to the chain_monitor being fully configured in some cases.
-               // See the docs for `ChannelManagerReadArgs` for more.
-
-               let block_hash = header.block_hash();
-               log_trace!(self.logger, "New best block: {} at height {}", block_hash, height);
-
-               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
-
-               *self.best_block.write().unwrap() = BestBlock::new(block_hash, height);
-
-               self.do_chain_event(Some(height), |channel| channel.update_best_block(height, header.time));
-
-               loop {
-                       // Update last_node_announcement_serial to be the max of its current value and the
-                       // block timestamp. This should keep us close to the current time without relying on
-                       // having an explicit local time source.
-                       // Just in case we end up in a race, we loop until we either successfully update
-                       // last_node_announcement_serial or decide we don't need to.
-                       let old_serial = self.last_node_announcement_serial.load(Ordering::Acquire);
-                       if old_serial >= header.time as usize { break; }
-                       if self.last_node_announcement_serial.compare_exchange(old_serial, header.time as usize, Ordering::AcqRel, Ordering::Relaxed).is_ok() {
-                               break;
-                       }
-               }
-       }
-
-       /// Gets the set of txids which should be monitored for their confirmation state.
-       ///
-       /// If you're providing information about reorganizations via [`transaction_unconfirmed`], this
-       /// is the set of transactions which you may need to call [`transaction_unconfirmed`] for.
-       ///
-       /// This may be useful to poll to determine the set of transactions which must be registered
-       /// with an Electrum server or for which an Electrum server needs to be polled to determine
-       /// transaction confirmation state.
-       ///
-       /// This may update after any [`transactions_confirmed`] or [`block_connected`] call.
-       ///
-       /// Note that this is NOT the set of transactions which must be included in calls to
-       /// [`transactions_confirmed`] if they are confirmed, but a small subset of it.
-       ///
-       /// [`transactions_confirmed`]: Self::transactions_confirmed
-       /// [`transaction_unconfirmed`]: Self::transaction_unconfirmed
-       /// [`block_connected`]: chain::Listen::block_connected
-       pub fn get_relevant_txids(&self) -> Vec<Txid> {
-               let channel_state = self.channel_state.lock().unwrap();
-               let mut res = Vec::with_capacity(channel_state.short_to_id.len());
-               for chan in channel_state.by_id.values() {
-                       if let Some(funding_txo) = chan.get_funding_txo() {
-                               res.push(funding_txo.txid);
-                       }
-               }
-               res
-       }
-
-       /// Marks a transaction as having been reorganized out of the blockchain.
-       ///
-       /// If a transaction is included in [`get_relevant_txids`], and is no longer in the main branch
-       /// of the blockchain, this function should be called to indicate that the transaction should
-       /// be considered reorganized out.
-       ///
-       /// Once this is called, the given transaction will no longer appear on [`get_relevant_txids`],
-       /// though this may be called repeatedly for a given transaction without issue.
-       ///
-       /// Note that if the transaction is confirmed on the main chain in a different block (indicated
-       /// via a call to [`transactions_confirmed`]), it may re-appear in [`get_relevant_txids`], thus
-       /// be very wary of race-conditions wherein the final state of a transaction indicated via
-       /// these APIs is not the same as its state on the blockchain.
-       ///
-       /// [`transactions_confirmed`]: Self::transactions_confirmed
-       /// [`get_relevant_txids`]: Self::get_relevant_txids
-       pub fn transaction_unconfirmed(&self, txid: &Txid) {
-               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
-               self.do_chain_event(None, |channel| {
-                       if let Some(funding_txo) = channel.get_funding_txo() {
-                               if funding_txo.txid == *txid {
-                                       channel.funding_transaction_unconfirmed().map(|_| (None, Vec::new()))
-                               } else { Ok((None, Vec::new())) }
-                       } else { Ok((None, Vec::new())) }
-               });
-       }
-
        /// Blocks until ChannelManager needs to be persisted or a timeout is reached. It returns a bool
        /// indicating whether persistence is necessary. Only one listener on
        /// `await_persistable_update` or `await_persistable_update_timeout` is guaranteed to be woken
@@ -3952,7 +4064,8 @@ impl Writeable for PendingHTLCInfo {
                        },
                        &PendingHTLCRouting::Receive { ref payment_data, ref incoming_cltv_expiry } => {
                                1u8.write(writer)?;
-                               payment_data.write(writer)?;
+                               payment_data.payment_secret.write(writer)?;
+                               payment_data.total_msat.write(writer)?;
                                incoming_cltv_expiry.write(writer)?;
                        },
                }
@@ -3973,7 +4086,10 @@ impl Readable for PendingHTLCInfo {
                                        short_channel_id: Readable::read(reader)?,
                                },
                                1u8 => PendingHTLCRouting::Receive {
-                                       payment_data: Readable::read(reader)?,
+                                       payment_data: msgs::FinalOnionHopData {
+                                               payment_secret: Readable::read(reader)?,
+                                               total_msat: Readable::read(reader)?,
+                                       },
                                        incoming_cltv_expiry: Readable::read(reader)?,
                                },
                                _ => return Err(DecodeError::InvalidValue),
@@ -4045,12 +4161,29 @@ impl_writeable!(HTLCPreviousHopData, 0, {
        incoming_packet_shared_secret
 });
 
-impl_writeable!(ClaimableHTLC, 0, {
-       prev_hop,
-       value,
-       payment_data,
-       cltv_expiry
-});
+impl Writeable for ClaimableHTLC {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+               self.prev_hop.write(writer)?;
+               self.value.write(writer)?;
+               self.payment_data.payment_secret.write(writer)?;
+               self.payment_data.total_msat.write(writer)?;
+               self.cltv_expiry.write(writer)
+       }
+}
+
+impl Readable for ClaimableHTLC {
+       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+               Ok(ClaimableHTLC {
+                       prev_hop: Readable::read(reader)?,
+                       value: Readable::read(reader)?,
+                       payment_data: msgs::FinalOnionHopData {
+                               payment_secret: Readable::read(reader)?,
+                               total_msat: Readable::read(reader)?,
+                       },
+                       cltv_expiry: Readable::read(reader)?,
+               })
+       }
+}
 
 impl Writeable for HTLCSource {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
@@ -4152,6 +4285,14 @@ impl Readable for HTLCForwardInfo {
        }
 }
 
+impl_writeable!(PendingInboundPayment, 0, {
+       payment_secret,
+       expiry_time,
+       user_payment_id,
+       payment_preimage,
+       min_value_msat
+});
+
 impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> Writeable for ChannelManager<Signer, M, T, K, F, L>
        where M::Target: chain::Watch<Signer>,
         T::Target: BroadcasterInterface,
@@ -4231,6 +4372,14 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> Writeable f
                }
 
                (self.last_node_announcement_serial.load(Ordering::Acquire) as u32).write(writer)?;
+               (self.highest_seen_timestamp.load(Ordering::Acquire) as u32).write(writer)?;
+
+               let pending_inbound_payments = self.pending_inbound_payments.lock().unwrap();
+               (pending_inbound_payments.len() as u64).write(writer)?;
+               for (hash, pending_payment) in pending_inbound_payments.iter() {
+                       hash.write(writer)?;
+                       pending_payment.write(writer)?;
+               }
 
                Ok(())
        }
@@ -4461,6 +4610,15 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                }
 
                let last_node_announcement_serial: u32 = Readable::read(reader)?;
+               let highest_seen_timestamp: u32 = Readable::read(reader)?;
+
+               let pending_inbound_payment_count: u64 = Readable::read(reader)?;
+               let mut pending_inbound_payments: HashMap<PaymentHash, PendingInboundPayment> = HashMap::with_capacity(cmp::min(pending_inbound_payment_count as usize, MAX_ALLOC_SIZE/(3*32)));
+               for _ in 0..pending_inbound_payment_count {
+                       if pending_inbound_payments.insert(Readable::read(reader)?, Readable::read(reader)?).is_some() {
+                               return Err(DecodeError::InvalidValue);
+                       }
+               }
 
                let mut secp_ctx = Secp256k1::new();
                secp_ctx.seeded_randomize(&args.keys_manager.get_secure_random_bytes());
@@ -4480,11 +4638,14 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                claimable_htlcs,
                                pending_msg_events: Vec::new(),
                        }),
+                       pending_inbound_payments: Mutex::new(pending_inbound_payments),
+
                        our_network_key: args.keys_manager.get_node_secret(),
                        our_network_pubkey: PublicKey::from_secret_key(&secp_ctx, &args.keys_manager.get_node_secret()),
                        secp_ctx,
 
                        last_node_announcement_serial: AtomicUsize::new(last_node_announcement_serial as usize),
+                       highest_seen_timestamp: AtomicUsize::new(highest_seen_timestamp as usize),
 
                        per_peer_state: RwLock::new(per_peer_state),
 
@@ -4567,7 +4728,7 @@ pub mod bench {
        use chain::channelmonitor::Persist;
        use chain::keysinterface::{KeysManager, InMemorySigner};
        use ln::channelmanager::{BestBlock, ChainParameters, ChannelManager, PaymentHash, PaymentPreimage};
-       use ln::features::InitFeatures;
+       use ln::features::{InitFeatures, InvoiceFeatures};
        use ln::functional_test_utils::*;
        use ln::msgs::ChannelMessageHandler;
        use routing::network_graph::NetworkGraph;
@@ -4661,15 +4822,20 @@ pub mod bench {
 
                let dummy_graph = NetworkGraph::new(genesis_hash);
 
+               let mut payment_count: u64 = 0;
                macro_rules! send_payment {
                        ($node_a: expr, $node_b: expr) => {
                                let usable_channels = $node_a.list_usable_channels();
-                               let route = get_route(&$node_a.get_our_node_id(), &dummy_graph, &$node_b.get_our_node_id(), None, Some(&usable_channels.iter().map(|r| r).collect::<Vec<_>>()), &[], 10_000, TEST_FINAL_CLTV, &logger_a).unwrap();
+                               let route = get_route(&$node_a.get_our_node_id(), &dummy_graph, &$node_b.get_our_node_id(), Some(InvoiceFeatures::known()),
+                                       Some(&usable_channels.iter().map(|r| r).collect::<Vec<_>>()), &[], 10_000, TEST_FINAL_CLTV, &logger_a).unwrap();
 
-                               let payment_preimage = PaymentPreimage([0; 32]);
+                               let mut payment_preimage = PaymentPreimage([0; 32]);
+                               payment_preimage.0[0..8].copy_from_slice(&payment_count.to_le_bytes());
+                               payment_count += 1;
                                let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner());
+                               let payment_secret = $node_b.create_inbound_payment_for_hash(payment_hash, None, 7200, 0).unwrap();
 
-                               $node_a.send_payment(&route, payment_hash, &None).unwrap();
+                               $node_a.send_payment(&route, payment_hash, &Some(payment_secret)).unwrap();
                                let payment_event = SendEvent::from_event($node_a.get_and_clear_pending_msg_events().pop().unwrap());
                                $node_b.handle_update_add_htlc(&$node_a.get_our_node_id(), &payment_event.msgs[0]);
                                $node_b.handle_commitment_signed(&$node_a.get_our_node_id(), &payment_event.commitment_msg);
@@ -4679,8 +4845,8 @@ pub mod bench {
                                $node_b.handle_revoke_and_ack(&$node_a.get_our_node_id(), &get_event_msg!(NodeHolder { node: &$node_a }, MessageSendEvent::SendRevokeAndACK, $node_b.get_our_node_id()));
 
                                expect_pending_htlcs_forwardable!(NodeHolder { node: &$node_b });
-                               expect_payment_received!(NodeHolder { node: &$node_b }, payment_hash, 10_000);
-                               assert!($node_b.claim_funds(payment_preimage, &None, 10_000));
+                               expect_payment_received!(NodeHolder { node: &$node_b }, payment_hash, payment_secret, 10_000);
+                               assert!($node_b.claim_funds(payment_preimage));
 
                                match $node_b.get_and_clear_pending_msg_events().pop().unwrap() {
                                        MessageSendEvent::UpdateHTLCs { node_id, updates } => {