]> git.bitcoin.ninja Git - rust-lightning/commitdiff
Make payments not duplicatively fail/succeed on reload/reconnect
authorMatt Corallo <git@bluematt.me>
Sun, 9 May 2021 19:19:11 +0000 (19:19 +0000)
committerMatt Corallo <git@bluematt.me>
Thu, 20 May 2021 16:30:27 +0000 (16:30 +0000)
We currently generate duplicative PaymentFailed/PaymentSent events
in two cases:

a) If we receive a update_fulfill_htlc message, followed by a
   disconnect, then a resend of the same update_fulfill_htlc
   message, we will generate a PaymentSent event for each message.

b) When a Channel is closed, any outbound HTLCs which were relayed
   through it are simply dropped when the Channel is. From there,
   the ChannelManager relies on the ChannelMonitor having a copy of
   the relevant fail-/claim-back data and processes the HTLC
   fail/claim when the ChannelMonitor tells it to.

   If, due to an on-chain event, an HTLC is failed/claimed, and
   then we serialize the ChannelManager, but do not re-serialize
   the relevant ChannelMonitor, we may end up getting a duplicative
   event.

In order to provide the expected consistency, we add explicit
tracking of pending outbound payments using their unique
session_priv field which is generated when the payment is sent.
Then, before generating PaymentFailed/PaymentSent events, we check
that the session_priv for the payment is still pending.

Thix fixes #209.

lightning/src/ln/channelmanager.rs
lightning/src/util/events.rs

index 54bd3c89ff3f9d94789d576623ab6373f76b7821..52bd8ad1cdbd82fdba046839f3497c49c8a775f2 100644 (file)
@@ -442,6 +442,18 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
        /// Locked *after* channel_state.
        pending_inbound_payments: Mutex<HashMap<PaymentHash, PendingInboundPayment>>,
 
+       /// The session_priv bytes of outbound payments which are pending resolution.
+       /// The authoritative state of these HTLCs resides either within Channels or ChannelMonitors
+       /// (if the channel has been force-closed), however we track them here to prevent duplicative
+       /// PaymentSent/PaymentFailed events. Specifically, in the case of a duplicative
+       /// update_fulfill_htlc message after a reconnect, we may "claim" a payment twice.
+       /// Additionally, because ChannelMonitors are often not re-serialized after connecting block(s)
+       /// which may generate a claim event, we may receive similar duplicate claim/fail MonitorEvents
+       /// after reloading from disk while replaying blocks against ChannelMonitors.
+       ///
+       /// Locked *after* channel_state.
+       pending_outbound_payments: Mutex<HashSet<[u8; 32]>>,
+
        our_network_key: SecretKey,
        our_network_pubkey: PublicKey,
 
@@ -913,6 +925,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                pending_msg_events: Vec::new(),
                        }),
                        pending_inbound_payments: Mutex::new(HashMap::new()),
+                       pending_outbound_payments: Mutex::new(HashSet::new()),
 
                        our_network_key: keys_manager.get_node_secret(),
                        our_network_pubkey: PublicKey::from_secret_key(&secp_ctx, &keys_manager.get_node_secret()),
@@ -1467,7 +1480,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        pub(crate) fn send_payment_along_path(&self, path: &Vec<RouteHop>, payment_hash: &PaymentHash, payment_secret: &Option<PaymentSecret>, total_value: u64, cur_height: u32) -> Result<(), APIError> {
                log_trace!(self.logger, "Attempting to send payment for path with next hop {}", path.first().unwrap().short_channel_id);
                let prng_seed = self.keys_manager.get_secure_random_bytes();
-               let session_priv = SecretKey::from_slice(&self.keys_manager.get_secure_random_bytes()[..]).expect("RNG is busted");
+               let session_priv_bytes = self.keys_manager.get_secure_random_bytes();
+               let session_priv = SecretKey::from_slice(&session_priv_bytes[..]).expect("RNG is busted");
 
                let onion_keys = onion_utils::construct_onion_keys(&self.secp_ctx, &path, &session_priv)
                        .map_err(|_| APIError::RouteError{err: "Pubkey along hop was maliciously selected"})?;
@@ -1478,6 +1492,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash);
 
                let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
+               assert!(self.pending_outbound_payments.lock().unwrap().insert(session_priv_bytes));
 
                let err: Result<(), _> = loop {
                        let mut channel_lock = self.channel_state.lock().unwrap();
@@ -2228,17 +2243,25 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        self.fail_htlc_backwards_internal(channel_state,
                                                htlc_src, &payment_hash, HTLCFailReason::Reason { failure_code, data: onion_failure_data});
                                },
-                               HTLCSource::OutboundRoute { .. } => {
-                                       self.pending_events.lock().unwrap().push(
-                                               events::Event::PaymentFailed {
-                                                       payment_hash,
-                                                       rejected_by_dest: false,
+                               HTLCSource::OutboundRoute { session_priv, .. } => {
+                                       if {
+                                               let mut session_priv_bytes = [0; 32];
+                                               session_priv_bytes.copy_from_slice(&session_priv[..]);
+                                               self.pending_outbound_payments.lock().unwrap().remove(&session_priv_bytes)
+                                       } {
+                                               self.pending_events.lock().unwrap().push(
+                                                       events::Event::PaymentFailed {
+                                                               payment_hash,
+                                                               rejected_by_dest: false,
 #[cfg(test)]
-                                                       error_code: None,
+                                                               error_code: None,
 #[cfg(test)]
-                                                       error_data: None,
-                                               }
-                                       )
+                                                               error_data: None,
+                                                       }
+                                               )
+                                       } else {
+                                               log_trace!(self.logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
+                                       }
                                },
                        };
                }
@@ -2260,7 +2283,15 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                // from block_connected which may run during initialization prior to the chain_monitor
                // being fully configured. See the docs for `ChannelManagerReadArgs` for more.
                match source {
-                       HTLCSource::OutboundRoute { ref path, .. } => {
+                       HTLCSource::OutboundRoute { ref path, session_priv, .. } => {
+                               if {
+                                       let mut session_priv_bytes = [0; 32];
+                                       session_priv_bytes.copy_from_slice(&session_priv[..]);
+                                       !self.pending_outbound_payments.lock().unwrap().remove(&session_priv_bytes)
+                               } {
+                                       log_trace!(self.logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
+                                       return;
+                               }
                                log_trace!(self.logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
                                mem::drop(channel_state_lock);
                                match &onion_error {
@@ -2489,12 +2520,20 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
        fn claim_funds_internal(&self, mut channel_state_lock: MutexGuard<ChannelHolder<Signer>>, source: HTLCSource, payment_preimage: PaymentPreimage) {
                match source {
-                       HTLCSource::OutboundRoute { .. } => {
+                       HTLCSource::OutboundRoute { session_priv, .. } => {
                                mem::drop(channel_state_lock);
-                               let mut pending_events = self.pending_events.lock().unwrap();
-                               pending_events.push(events::Event::PaymentSent {
-                                       payment_preimage
-                               });
+                               if {
+                                       let mut session_priv_bytes = [0; 32];
+                                       session_priv_bytes.copy_from_slice(&session_priv[..]);
+                                       self.pending_outbound_payments.lock().unwrap().remove(&session_priv_bytes)
+                               } {
+                                       let mut pending_events = self.pending_events.lock().unwrap();
+                                       pending_events.push(events::Event::PaymentSent {
+                                               payment_preimage
+                                       });
+                               } else {
+                                       log_trace!(self.logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
+                               }
                        },
                        HTLCSource::PreviousHopData(hop_data) => {
                                let prev_outpoint = hop_data.outpoint;
@@ -4470,6 +4509,12 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> Writeable f
                        pending_payment.write(writer)?;
                }
 
+               let pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
+               (pending_outbound_payments.len() as u64).write(writer)?;
+               for session_priv in pending_outbound_payments.iter() {
+                       session_priv.write(writer)?;
+               }
+
                Ok(())
        }
 }
@@ -4709,6 +4754,14 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        }
                }
 
+               let pending_outbound_payments_count: u64 = Readable::read(reader)?;
+               let mut pending_outbound_payments: HashSet<[u8; 32]> = HashSet::with_capacity(cmp::min(pending_outbound_payments_count as usize, MAX_ALLOC_SIZE/32));
+               for _ in 0..pending_outbound_payments_count {
+                       if !pending_outbound_payments.insert(Readable::read(reader)?) {
+                               return Err(DecodeError::InvalidValue);
+                       }
+               }
+
                let mut secp_ctx = Secp256k1::new();
                secp_ctx.seeded_randomize(&args.keys_manager.get_secure_random_bytes());
 
@@ -4728,6 +4781,7 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                pending_msg_events: Vec::new(),
                        }),
                        pending_inbound_payments: Mutex::new(pending_inbound_payments),
+                       pending_outbound_payments: Mutex::new(pending_outbound_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()),
index 798f562526fa8acbba55e4353e94c08b03d50980..599ed2afa68c0b7d2363904959a6daadb9a72c10 100644 (file)
@@ -95,8 +95,6 @@ pub enum Event {
        },
        /// Indicates an outbound payment we made succeeded (ie it made it all the way to its target
        /// and we got back the payment preimage for it).
-       /// Note that duplicative PaymentSent Events may be generated - it is your responsibility to
-       /// deduplicate them by payment_preimage (which MUST be unique)!
        PaymentSent {
                /// The preimage to the hash given to ChannelManager::send_payment.
                /// Note that this serves as a payment receipt, if you wish to have such a thing, you must
@@ -105,8 +103,6 @@ pub enum Event {
        },
        /// Indicates an outbound payment we made failed. Probably some intermediary node dropped
        /// something. You may wish to retry with a different route.
-       /// Note that duplicative PaymentFailed Events may be generated - it is your responsibility to
-       /// deduplicate them by payment_hash (which MUST be unique)!
        PaymentFailed {
                /// The hash which was given to ChannelManager::send_payment.
                payment_hash: PaymentHash,