Clarify roles in failing HTLCs, impl it, support rebalances 2018-03-htlc-failures
authorMatt Corallo <git@bluematt.me>
Tue, 20 Mar 2018 23:11:27 +0000 (19:11 -0400)
committerMatt Corallo <git@bluematt.me>
Thu, 22 Mar 2018 21:35:30 +0000 (17:35 -0400)
src/ln/channel.rs
src/ln/channelmanager.rs
src/ln/msgs.rs
src/ln/peer_handler.rs
src/ln/router.rs
src/util/events.rs

index 10cfb8bd9255d01ee5c855db61aac84e26a8ce81..ef73db8eb813b2dea164cc00a4b245924c1898a1 100644 (file)
@@ -782,8 +782,9 @@ impl Channel {
                        return Err(HandleError{err: "Unable to find a pending HTLC which matched the given payment preimage", msg: None});
                }
 
+               //TODO: This is racy af, they may have pending messages in flight to us that will not have
+               //received this yet!
                self.value_to_self_msat += htlc_amount_msat;
-
                Ok(msgs::UpdateFulfillHTLC {
                        channel_id: self.channel_id(),
                        htlc_id: htlc_id,
@@ -791,6 +792,37 @@ impl Channel {
                })
        }
 
+       pub fn get_update_fail_htlc(&mut self, payment_hash: &[u8; 32], err_packet: msgs::OnionErrorPacket) -> Result<msgs::UpdateFailHTLC, HandleError> {
+               if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
+                       return Err(HandleError{err: "Was asked to fail an HTLC when channel was not in an operational state", msg: None});
+               }
+
+               let mut htlc_id = 0;
+               let mut htlc_amount_msat = 0;
+               self.pending_htlcs.retain(|ref htlc| {
+                       if !htlc.outbound && htlc.payment_hash == *payment_hash {
+                               if htlc_id != 0 {
+                                       panic!("Duplicate HTLC payment_hash, you probably re-used payment preimages, NEVER DO THIS!");
+                               }
+                               htlc_id = htlc.htlc_id;
+                               htlc_amount_msat += htlc.amount_msat;
+                               false
+                       } else { true }
+               });
+               if htlc_amount_msat == 0 {
+                       return Err(HandleError{err: "Unable to find a pending HTLC which matched the given payment preimage", msg: None});
+               }
+
+               //TODO: This is racy af, they may have pending messages in flight to us that will not have
+               //received this yet!
+
+               Ok(msgs::UpdateFailHTLC {
+                       channel_id: self.channel_id(),
+                       htlc_id,
+                       reason: err_packet
+               })
+       }
+
        // Message handlers:
 
        pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel) -> Result<(), HandleError> {
@@ -1010,7 +1042,7 @@ impl Channel {
        }
 
        /// Removes an outbound HTLC which has been commitment_signed by the remote end
-       fn remove_htlc(&mut self, htlc_id: u64, check_preimage: Option<[u8; 32]>) -> Result<HTLCOutput, HandleError> {
+       fn remove_outbound_htlc(&mut self, htlc_id: u64, check_preimage: Option<[u8; 32]>) -> Result<HTLCOutput, HandleError> {
                let mut found_idx = None;
                for (idx, ref htlc) in self.pending_htlcs.iter().enumerate() {
                        if htlc.outbound && htlc.htlc_id == htlc_id {
@@ -1026,7 +1058,7 @@ impl Channel {
                        }
                }
                match found_idx {
-                       None => Err(HandleError{err: "Remote tried to fulfill an HTLC we couldn't find", msg: None}),
+                       None => Err(HandleError{err: "Remote tried to fulfill/fail an HTLC we couldn't find", msg: None}),
                        Some(idx) => {
                                Ok(self.pending_htlcs.swap_remove(idx))
                        }
@@ -1096,9 +1128,7 @@ impl Channel {
                let mut payment_hash = [0; 32];
                sha.result(&mut payment_hash);
 
-               //TODO: Tell channel_monitor about the payment_preimage
-
-               match self.remove_htlc(msg.htlc_id, Some(payment_hash)) {
+               match self.remove_outbound_htlc(msg.htlc_id, Some(payment_hash)) {
                        Err(e) => return Err(e),
                        Ok(htlc) => {
                                //TODO: Double-check that we didn't exceed some limits (or value_to_self went
@@ -1110,43 +1140,40 @@ impl Channel {
                self.check_and_free_holding_cell_htlcs()
        }
 
-
-       pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC) -> Result<Option<(Vec<msgs::UpdateAddHTLC>, msgs::CommitmentSigned)>, HandleError> {
+       pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC) -> Result<([u8; 32], Option<(Vec<msgs::UpdateAddHTLC>, msgs::CommitmentSigned)>), HandleError> {
                if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
                        return Err(HandleError{err: "Got add HTLC message when channel was not in an operational state", msg: None});
                }
 
-               //TODO: Lots of checks here (and implementation after the remove?)
-
-               match self.remove_htlc(msg.htlc_id, None) {
+               let payment_hash = match self.remove_outbound_htlc(msg.htlc_id, None) {
                        Err(e) => return Err(e),
-                       Ok(_htlc) => {
+                       Ok(htlc) => {
                                //TODO: Double-check that we didn't exceed some limits (or value_to_self went
                                //negative here?)
-                               ////TODO: Something?
+                               htlc.payment_hash
                        }
-               }
+               };
 
-               self.check_and_free_holding_cell_htlcs()
+               let holding_cell_freedom = self.check_and_free_holding_cell_htlcs()?;
+               Ok((payment_hash, holding_cell_freedom))
        }
 
-       pub fn update_fail_malformed_htlc(&mut self, msg: &msgs::UpdateFailMalformedHTLC) -> Result<Option<(Vec<msgs::UpdateAddHTLC>, msgs::CommitmentSigned)>, HandleError> {
+       pub fn update_fail_malformed_htlc(&mut self, msg: &msgs::UpdateFailMalformedHTLC) -> Result<([u8; 32], Option<(Vec<msgs::UpdateAddHTLC>, msgs::CommitmentSigned)>), HandleError> {
                if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
                        return Err(HandleError{err: "Got add HTLC message when channel was not in an operational state", msg: None});
                }
 
-               //TODO: Lots of checks here (and implementation after the remove?)
-
-               match self.remove_htlc(msg.htlc_id, None) {
+               let payment_hash = match self.remove_outbound_htlc(msg.htlc_id, None) {
                        Err(e) => return Err(e),
-                       Ok(_htlc) => {
+                       Ok(htlc) => {
                                //TODO: Double-check that we didn't exceed some limits (or value_to_self went
                                //negative here?)
-                               ////TODO: Something?
+                               htlc.payment_hash
                        }
-               }
+               };
 
-               self.check_and_free_holding_cell_htlcs()
+               let holding_cell_freedom = self.check_and_free_holding_cell_htlcs()?;
+               Ok((payment_hash, holding_cell_freedom))
        }
 
        pub fn commitment_signed(&mut self, msg: &msgs::CommitmentSigned) -> Result<(msgs::RevokeAndACK, Vec<PendingForwardHTLCInfo>), HandleError> {
index b1577b0a8a89ec23f1b73490f30b322a2fee6cc2..14e089249cdd37adc089a40b772abbe486301ce0 100644 (file)
@@ -47,9 +47,29 @@ pub struct PendingForwardHTLCInfo {
        outgoing_cltv_value: u32,
 }
 
-struct ChannelHolder {
-       by_id: HashMap<Uint256, Channel>,
-       short_to_id: HashMap<u64, Uint256>,
+enum PendingOutboundHTLC {
+       IntermediaryHopData {
+               source_short_channel_id: u64,
+               incoming_packet_shared_secret: SharedSecret,
+       },
+       OutboundRoute {
+               route: Route,
+       },
+       /// Used for channel rebalancing
+       CycledRoute {
+               source_short_channel_id: u64,
+               incoming_packet_shared_secret: SharedSecret,
+               route: Route,
+       }
+}
+
+enum HTLCFailReason<'a> {
+       ErrorPacket {
+               err: &'a msgs::OnionErrorPacket,
+       },
+       Reason {
+               failure_code: u16,
+       }
 }
 
 /// We hold back HTLCs we intend to relay for a random interval in the range (this, 5*this). This
@@ -58,10 +78,33 @@ struct ChannelHolder {
 /// probably increase this significantly.
 const MIN_HTLC_RELAY_HOLDING_CELL_MILLIS: u32 = 50;
 
-struct PendingForwardableHTLCs {
+struct ChannelHolder {
+       by_id: HashMap<Uint256, Channel>,
+       short_to_id: HashMap<u64, Uint256>,
        next_forward: Instant,
        /// short channel id -> forward infos. Key of 0 means payments received
        forward_htlcs: HashMap<u64, Vec<PendingForwardHTLCInfo>>,
+       claimable_htlcs: HashMap<[u8; 32], PendingOutboundHTLC>,
+}
+struct MutChannelHolder<'a> {
+       by_id: &'a mut HashMap<Uint256, Channel>,
+       short_to_id: &'a mut HashMap<u64, Uint256>,
+       next_forward: &'a mut Instant,
+       /// short channel id -> forward infos. Key of 0 means payments received
+       forward_htlcs: &'a mut HashMap<u64, Vec<PendingForwardHTLCInfo>>,
+       claimable_htlcs: &'a mut HashMap<[u8; 32], PendingOutboundHTLC>,
+}
+impl ChannelHolder {
+       fn borrow_parts(&mut self) -> MutChannelHolder {
+               MutChannelHolder {
+                       by_id: &mut self.by_id,
+                       short_to_id: &mut self.short_to_id,
+                       next_forward: &mut self.next_forward,
+                       /// short channel id -> forward infos. Key of 0 means payments received
+                       forward_htlcs: &mut self.forward_htlcs,
+                       claimable_htlcs: &mut self.claimable_htlcs,
+               }
+       }
 }
 
 /// Manager which keeps track of a number of channels and sends messages to the appropriate
@@ -78,12 +121,10 @@ pub struct ChannelManager {
        fee_proportional_millionths: u32,
        secp_ctx: Secp256k1,
 
-       channels: Mutex<ChannelHolder>,
+       channel_state: Mutex<ChannelHolder>,
        our_network_key: SecretKey,
 
        pending_events: Mutex<Vec<events::Event>>,
-       pending_htlcs_forwardable: Mutex<PendingForwardableHTLCs>,
-       pending_claimable_htlcs: Mutex<HashMap<[u8; 32], u64>>,
 }
 
 const CLTV_EXPIRY_DELTA: u16 = 6 * 24 * 2; //TODO?
@@ -127,15 +168,16 @@ impl ChannelManager {
                        fee_proportional_millionths: fee_proportional_millionths,
                        secp_ctx: secp_ctx,
 
-                       channels: Mutex::new(ChannelHolder{by_id: HashMap::new(), short_to_id: HashMap::new()}),
-                       our_network_key: our_network_key,
-
-                       pending_events: Mutex::new(Vec::new()),
-                       pending_htlcs_forwardable: Mutex::new(PendingForwardableHTLCs {
+                       channel_state: Mutex::new(ChannelHolder{
+                               by_id: HashMap::new(),
+                               short_to_id: HashMap::new(),
                                next_forward: Instant::now(),
                                forward_htlcs: HashMap::new(),
+                               claimable_htlcs: HashMap::new(),
                        }),
-                       pending_claimable_htlcs: Mutex::new(HashMap::new()),
+                       our_network_key: our_network_key,
+
+                       pending_events: Mutex::new(Vec::new()),
                });
                let weak_res = Arc::downgrade(&res);
                res.chain_monitor.register_listener(weak_res);
@@ -145,8 +187,8 @@ impl ChannelManager {
        pub fn create_channel(&self, their_network_key: PublicKey, channel_value_satoshis: u64, user_id: u64) -> Result<msgs::OpenChannel, HandleError> {
                let channel = Channel::new_outbound(&*self.fee_estimator, their_network_key, channel_value_satoshis, self.announce_channels_publicly, user_id);
                let res = channel.get_open_channel(self.genesis_hash.clone(), &*self.fee_estimator)?;
-               let mut channels = self.channels.lock().unwrap();
-               match channels.by_id.insert(channel.channel_id(), channel) {
+               let mut channel_state = self.channel_state.lock().unwrap();
+               match channel_state.by_id.insert(channel.channel_id(), channel) {
                        Some(_) => panic!("RNG is bad???"),
                        None => Ok(res)
                }
@@ -415,13 +457,19 @@ impl ChannelManager {
        /// first hop in route. Value parameters are provided via the last hop in route, see
        /// documentation for RouteHop fields for more info.
        /// See-also docs on Channel::send_htlc_and_commit.
-       pub fn send_payment(&self, route: &Route, payment_hash: [u8; 32]) -> Result<Option<(msgs::UpdateAddHTLC, msgs::CommitmentSigned)>, HandleError> {
+       pub fn send_payment(&self, route: Route, payment_hash: [u8; 32]) -> Result<Option<(msgs::UpdateAddHTLC, msgs::CommitmentSigned)>, HandleError> {
                if route.hops.len() < 1 || route.hops.len() > 20 {
                        return Err(HandleError{err: "Route didn't go anywhere/had bogus size", msg: None});
                }
+               let our_node_id = self.get_our_node_id();
+               for (idx, hop) in route.hops.iter().enumerate() {
+                       if idx != route.hops.len() - 1 && hop.pubkey == our_node_id {
+                               return Err(HandleError{err: "Route went through us but wasn't a simple rebalance loop to us", msg: None});
+                       }
+               }
 
                let mut rng = thread_rng();
-               let session_priv = secp_call!(SecretKey::from_slice(&self.secp_ctx, & {
+               let session_priv = secp_call!(SecretKey::from_slice(&self.secp_ctx, &{
                        let mut session_key = [0; 32];
                        rng.fill_bytes(&mut session_key);
                        session_key
@@ -429,28 +477,40 @@ impl ChannelManager {
 
                let associated_data = Vec::new(); //TODO: What to put here?
 
-               let onion_keys = ChannelManager::construct_onion_keys(&self.secp_ctx, route, &session_priv)?;
-               let (onion_payloads, htlc_msat, htlc_cltv) = ChannelManager::build_onion_payloads(route)?;
+               let onion_keys = ChannelManager::construct_onion_keys(&self.secp_ctx, &route, &session_priv)?;
+               let (onion_payloads, htlc_msat, htlc_cltv) = ChannelManager::build_onion_payloads(&route)?;
                let onion_packet = ChannelManager::construct_onion_packet(onion_payloads, onion_keys, associated_data)?;
 
-               let mut channels = self.channels.lock().unwrap();
-               let id = match channels.short_to_id.get(&route.hops.first().unwrap().short_channel_id) {
+               let mut channel_state = self.channel_state.lock().unwrap();
+               let id = match channel_state.short_to_id.get(&route.hops.first().unwrap().short_channel_id) {
                        None => return Err(HandleError{err: "No channel available with first hop!", msg: None}),
                        Some(id) => id.clone()
                };
-               let chan = channels.by_id.get_mut(&id).unwrap();
-               if chan.get_their_node_id() != route.hops.first().unwrap().pubkey {
-                       return Err(HandleError{err: "Node ID mismatch on first hop!", msg: None});
+               let res = {
+                       let chan = channel_state.by_id.get_mut(&id).unwrap();
+                       if chan.get_their_node_id() != route.hops.first().unwrap().pubkey {
+                               return Err(HandleError{err: "Node ID mismatch on first hop!", msg: None});
+                       }
+                       chan.send_htlc_and_commit(htlc_msat, payment_hash.clone(), htlc_cltv, onion_packet)?
+               };
+
+               if channel_state.claimable_htlcs.insert(payment_hash, PendingOutboundHTLC::OutboundRoute {
+                       route: route,
+               }).is_some() {
+                       // TODO: We need to track these better, we're not generating these, so a
+                       // third-party might make this happen:
+                       panic!("payment_hash was repeated! Don't let this happen");
                }
-               chan.send_htlc_and_commit(htlc_msat, payment_hash, htlc_cltv, onion_packet)
+
+               Ok(res)
        }
 
        /// Call this upon creation of a funding transaction for the given channel.
        /// Panics if a funding transaction has already been provided for this channel.
        pub fn funding_transaction_generated(&self, temporary_channel_id: &Uint256, funding_txo: (Sha256dHash, u16)) {
                let (chan, msg) = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.remove(&temporary_channel_id) {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.remove(&temporary_channel_id) {
                                Some(mut chan) => {
                                        match chan.get_outbound_funding_created(funding_txo.0, funding_txo.1) {
                                                Ok(funding_msg) => {
@@ -482,8 +542,8 @@ impl ChannelManager {
                        });
                }
 
-               let mut channels = self.channels.lock().unwrap();
-               channels.by_id.insert(chan.channel_id(), chan);
+               let mut channel_state = self.channel_state.lock().unwrap();
+               channel_state.by_id.insert(chan.channel_id(), chan);
        }
 
        fn get_announcement_sigs(&self, chan: &Channel) -> Result<Option<msgs::AnnouncementSignatures>, HandleError> {
@@ -502,44 +562,25 @@ impl ChannelManager {
        }
 
        pub fn process_pending_htlc_forward(&self) {
-               let forward_htlcs = {
-                       let mut pending_forwards = self.pending_htlcs_forwardable.lock().unwrap();
-                       if Instant::now() < pending_forwards.next_forward {
-                               return;
-                       }
-                       let mut new_map = HashMap::new();
-                       mem::swap(&mut new_map, &mut pending_forwards.forward_htlcs);
-                       new_map
-               };
-
                let mut new_events = Vec::new();
-
                {
-                       for (short_chan_id, pending_forwards) in forward_htlcs.iter() {
-                               let mut pending_claimable_htlcs = self.pending_claimable_htlcs.lock().unwrap();
-                               for forward_info in pending_forwards {
-                                       pending_claimable_htlcs.insert(forward_info.payment_hash, forward_info.prev_short_channel_id);
-                                       if *short_chan_id == 0 {
-                                               new_events.push(events::Event::PaymentReceived {
-                                                       payment_hash: forward_info.payment_hash,
-                                                       amt: forward_info.amt_to_forward,
-                                               });
-                                       }
-                               }
+                       let mut channel_state_lock = self.channel_state.lock().unwrap();
+                       let channel_state = channel_state_lock.borrow_parts();
+
+                       if Instant::now() < *channel_state.next_forward {
+                               return;
                        }
-               }
-               {
-                       let mut channels = self.channels.lock().unwrap();
-                       for (short_chan_id, pending_forwards) in forward_htlcs {
+
+                       for (short_chan_id, pending_forwards) in channel_state.forward_htlcs.drain() {
                                if short_chan_id != 0 {
-                                       let forward_chan_id = match channels.short_to_id.get(&short_chan_id) {
+                                       let forward_chan_id = match channel_state.short_to_id.get(&short_chan_id) {
                                                Some(chan_id) => chan_id.clone(),
                                                None => {
                                                        // TODO: Send a failure packet back on each pending_forward
                                                        continue;
                                                }
                                        };
-                                       let forward_chan = &mut channels.by_id.get_mut(&forward_chan_id).unwrap();
+                                       let forward_chan = &mut channel_state.by_id.get_mut(&forward_chan_id).unwrap();
 
                                        let mut add_htlc_msgs = Vec::new();
                                        for forward_info in pending_forwards {
@@ -579,6 +620,13 @@ impl ChannelManager {
                                                        commitment_msg: commitment_msg,
                                                });
                                        }
+                               } else {
+                                       for forward_info in pending_forwards {
+                                               new_events.push(events::Event::PaymentReceived {
+                                                       payment_hash: forward_info.payment_hash,
+                                                       amt: forward_info.amt_to_forward,
+                                               });
+                                       }
                                }
                        }
                }
@@ -592,47 +640,147 @@ impl ChannelManager {
                }
        }
 
+       /// Indicates that the preimage for payment_hash is unknown after a PaymentReceived event.
+       pub fn fail_htlc_backwards(&self, payment_hash: &[u8; 32]) -> bool {
+               self.fail_htlc_backwards_internal(payment_hash, HTLCFailReason::Reason { failure_code: 0x4000 | 15 })
+       }
+
+       fn fail_htlc_backwards_internal(&self, payment_hash: &[u8; 32], onion_error: HTLCFailReason) -> bool {
+               let mut channel_state = self.channel_state.lock().unwrap();
+               let mut pending_htlc = {
+                       match channel_state.claimable_htlcs.remove(payment_hash) {
+                               Some(pending_htlc) => pending_htlc,
+                               None => return false,
+                       }
+               };
+
+               match pending_htlc {
+                       PendingOutboundHTLC::CycledRoute { source_short_channel_id, incoming_packet_shared_secret, .. } => {
+                               pending_htlc = PendingOutboundHTLC::IntermediaryHopData { source_short_channel_id, incoming_packet_shared_secret };
+                       },
+                       _ => {}
+               }
+
+               match pending_htlc {
+                       PendingOutboundHTLC::CycledRoute { .. } => { panic!("WAT"); },
+                       PendingOutboundHTLC::OutboundRoute { .. } => {
+                               //TODO: DECRYPT route from OutboundRoute
+                               let mut pending_events = self.pending_events.lock().unwrap();
+                               pending_events.push(events::Event::PaymentFailed {
+                                       payment_hash: payment_hash.clone()
+                               });
+                               false
+                       },
+                       PendingOutboundHTLC::IntermediaryHopData { source_short_channel_id, incoming_packet_shared_secret } => {
+                               let err_packet = match onion_error {
+                                       HTLCFailReason::Reason { failure_code } => {
+                                               let packet = ChannelManager::build_failure_packet(&incoming_packet_shared_secret, failure_code, &[0; 0]).encode();
+                                               ChannelManager::encrypt_failure_packet(&incoming_packet_shared_secret, &packet)
+                                       },
+                                       HTLCFailReason::ErrorPacket { err } => {
+                                               ChannelManager::encrypt_failure_packet(&incoming_packet_shared_secret, &err.data)
+                                       }
+                               };
+
+                               let (node_id, fail_msg) = {
+                                       let chan_id = match channel_state.short_to_id.get(&source_short_channel_id) {
+                                               Some(chan_id) => chan_id.clone(),
+                                               None => return false
+                                       };
+
+                                       let chan = channel_state.by_id.get_mut(&chan_id).unwrap();
+                                       match chan.get_update_fail_htlc(payment_hash, err_packet) {
+                                               Ok(msg) => (chan.get_their_node_id(), msg),
+                                               Err(_e) => {
+                                                       //TODO: Do something with e?
+                                                       return false;
+                                               },
+                                       }
+                               };
+
+                               let mut pending_events = self.pending_events.lock().unwrap();
+                               pending_events.push(events::Event::SendFailHTLC {
+                                       node_id,
+                                       msg: fail_msg
+                               });
+
+                               true
+                       },
+               }
+       }
+
        /// Provides a payment preimage in response to a PaymentReceived event, returning true and
        /// 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!
        pub fn claim_funds(&self, payment_preimage: [u8; 32]) -> bool {
+               self.claim_funds_internal(payment_preimage, true)
+       }
+       pub fn claim_funds_internal(&self, payment_preimage: [u8; 32], from_user: bool) -> bool {
                let mut sha = Sha256::new();
                sha.input(&payment_preimage);
                let mut payment_hash = [0; 32];
                sha.result(&mut payment_hash);
 
-               let short_chan_id = {
-                       let mut pending_claimable_htlcs = self.pending_claimable_htlcs.lock().unwrap();
-                       match pending_claimable_htlcs.remove(&payment_hash) {
-                               Some(short_id) => short_id,
+               let mut channel_state = self.channel_state.lock().unwrap();
+               let mut pending_htlc = {
+                       match channel_state.claimable_htlcs.remove(&payment_hash) {
+                               Some(pending_htlc) => pending_htlc,
                                None => return false,
                        }
                };
 
-               let (node_id, fulfill_msg) = {
-                       let mut channels = self.channels.lock().unwrap();
-                       let chan_id = match channels.short_to_id.get(&short_chan_id) {
-                               Some(chan_id) => chan_id.clone(),
-                               None => return false
-                       };
+               match pending_htlc {
+                       PendingOutboundHTLC::CycledRoute { source_short_channel_id, incoming_packet_shared_secret, route } => {
+                               if from_user { // This was the end hop back to us
+                                       pending_htlc = PendingOutboundHTLC::IntermediaryHopData { source_short_channel_id, incoming_packet_shared_secret };
+                                       channel_state.claimable_htlcs.insert(payment_hash, PendingOutboundHTLC::OutboundRoute { route });
+                               } else { // This came from the first upstream node
+                                       // Bank error in our favor! Maybe we should tell the user this somehow???
+                                       pending_htlc = PendingOutboundHTLC::OutboundRoute { route };
+                                       channel_state.claimable_htlcs.insert(payment_hash, PendingOutboundHTLC::IntermediaryHopData { source_short_channel_id, incoming_packet_shared_secret });
+                               }
+                       },
+                       _ => {},
+               }
 
-                       let chan = channels.by_id.get_mut(&chan_id).unwrap();
-                       match chan.get_update_fulfill_htlc(payment_preimage) {
-                               Ok(msg) => (chan.get_their_node_id(), msg),
-                               Err(_e) => {
-                                       //TODO: Do something with e?
-                                       return false;
-                               },
-                       }
-               };
+               match pending_htlc {
+                       PendingOutboundHTLC::CycledRoute { .. } => { panic!("WAT"); },
+                       PendingOutboundHTLC::OutboundRoute { .. } => {
+                               if from_user {
+                                       panic!("Called claim_funds with a preimage for an outgoing payment. There is nothing we can do with this, and something is seriously wrong if you knew this...");
+                               }
+                               let mut pending_events = self.pending_events.lock().unwrap();
+                               pending_events.push(events::Event::PaymentSent {
+                                       payment_preimage
+                               });
+                               false
+                       },
+                       PendingOutboundHTLC::IntermediaryHopData { source_short_channel_id, .. } => {
+                               let (node_id, fulfill_msg) = {
+                                       let chan_id = match channel_state.short_to_id.get(&source_short_channel_id) {
+                                               Some(chan_id) => chan_id.clone(),
+                                               None => return false
+                                       };
 
-               let mut pending_events = self.pending_events.lock().unwrap();
-               pending_events.push(events::Event::SendFulfillHTLC {
-                       node_id: node_id,
-                       msg: fulfill_msg
-               });
+                                       let chan = channel_state.by_id.get_mut(&chan_id).unwrap();
+                                       match chan.get_update_fulfill_htlc(payment_preimage) {
+                                               Ok(msg) => (chan.get_their_node_id(), msg),
+                                               Err(_e) => {
+                                                       //TODO: Do something with e?
+                                                       return false;
+                                               },
+                                       }
+                               };
 
-               true
+                               let mut pending_events = self.pending_events.lock().unwrap();
+                               pending_events.push(events::Event::SendFulfillHTLC {
+                                       node_id: node_id,
+                                       msg: fulfill_msg
+                               });
+
+                               true
+                       },
+               }
        }
 
        /// Gets the node_id held by this ChannelManager
@@ -654,9 +802,9 @@ impl ChainListener for ChannelManager {
        fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) {
                let mut new_funding_locked_messages = Vec::new();
                {
-                       let mut channels = self.channels.lock().unwrap();
+                       let mut channel_state = self.channel_state.lock().unwrap();
                        let mut short_to_ids_to_insert = Vec::new();
-                       for channel in channels.by_id.values_mut() {
+                       for channel in channel_state.by_id.values_mut() {
                                match channel.block_connected(header, height, txn_matched, indexes_of_txn_matched) {
                                        Some(funding_locked) => {
                                                let announcement_sigs = match self.get_announcement_sigs(channel) {
@@ -677,7 +825,7 @@ impl ChainListener for ChannelManager {
                                }
                        }
                        for to_insert in short_to_ids_to_insert {
-                               channels.short_to_id.insert(to_insert.0, to_insert.1);
+                               channel_state.short_to_id.insert(to_insert.0, to_insert.1);
                        }
                }
                let mut pending_events = self.pending_events.lock().unwrap();
@@ -687,8 +835,8 @@ impl ChainListener for ChannelManager {
        }
 
        fn block_disconnected(&self, header: &BlockHeader) {
-               let mut channels = self.channels.lock().unwrap();
-               for channel in channels.by_id.values_mut() {
+               let mut channel_state = self.channel_state.lock().unwrap();
+               for channel in channel_state.by_id.values_mut() {
                        if channel.block_disconnected(header) {
                                //TODO Close channel here
                        }
@@ -702,20 +850,20 @@ impl ChannelMessageHandler for ChannelManager {
                if msg.chain_hash != self.genesis_hash {
                        return Err(HandleError{err: "Unknown genesis block hash", msg: None});
                }
-               let mut channels = self.channels.lock().unwrap();
-               if channels.by_id.contains_key(&msg.temporary_channel_id) {
+               let mut channel_state = self.channel_state.lock().unwrap();
+               if channel_state.by_id.contains_key(&msg.temporary_channel_id) {
                        return Err(HandleError{err: "temporary_channel_id collision!", msg: None});
                }
                let channel = Channel::new_from_req(&*self.fee_estimator, their_node_id.clone(), msg, 0, self.announce_channels_publicly)?;
                let accept_msg = channel.get_accept_channel()?;
-               channels.by_id.insert(channel.channel_id(), channel);
+               channel_state.by_id.insert(channel.channel_id(), channel);
                Ok(accept_msg)
        }
 
        fn handle_accept_channel(&self, their_node_id: &PublicKey, msg: &msgs::AcceptChannel) -> Result<(), HandleError> {
                let (value, output_script, user_id) = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.get_mut(&msg.temporary_channel_id) {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.get_mut(&msg.temporary_channel_id) {
                                Some(chan) => {
                                        if chan.get_their_node_id() != *their_node_id {
                                                return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -741,8 +889,8 @@ impl ChannelMessageHandler for ChannelManager {
                //funding_created a second time, or long after the first, or whatever (note this also
                //leaves the short_to_id map in a busted state.
                let chan = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.remove(&msg.temporary_channel_id) {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.remove(&msg.temporary_channel_id) {
                                Some(mut chan) => {
                                        if chan.get_their_node_id() != *their_node_id {
                                                return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -764,15 +912,15 @@ impl ChannelMessageHandler for ChannelManager {
                   // for a bogus channel.
                let chan_monitor = chan.0.channel_monitor();
                self.monitor.add_update_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor)?;
-               let mut channels = self.channels.lock().unwrap();
-               channels.by_id.insert(chan.1.channel_id, chan.0);
+               let mut channel_state = self.channel_state.lock().unwrap();
+               channel_state.by_id.insert(chan.1.channel_id, chan.0);
                Ok(chan.1)
        }
 
        fn handle_funding_signed(&self, their_node_id: &PublicKey, msg: &msgs::FundingSigned) -> Result<(), HandleError> {
                let (funding_txo, user_id) = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.get_mut(&msg.channel_id) {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.get_mut(&msg.channel_id) {
                                Some(chan) => {
                                        if chan.get_their_node_id() != *their_node_id {
                                                return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -792,8 +940,8 @@ impl ChannelMessageHandler for ChannelManager {
        }
 
        fn handle_funding_locked(&self, their_node_id: &PublicKey, msg: &msgs::FundingLocked) -> Result<Option<msgs::AnnouncementSignatures>, HandleError> {
-               let mut channels = self.channels.lock().unwrap();
-               match channels.by_id.get_mut(&msg.channel_id) {
+               let mut channel_state = self.channel_state.lock().unwrap();
+               match channel_state.by_id.get_mut(&msg.channel_id) {
                        Some(chan) => {
                                if chan.get_their_node_id() != *their_node_id {
                                        return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -999,10 +1147,11 @@ impl ChannelMessageHandler for ChannelManager {
                                }
                        };
 
-               let mut channels = self.channels.lock().unwrap();
+               let mut channel_state_lock = self.channel_state.lock().unwrap();
+               let channel_state = channel_state_lock.borrow_parts();
 
-               if pending_forward_info.short_channel_id != 0 {
-                       let forwarding_id = match channels.short_to_id.get(&pending_forward_info.short_channel_id) {
+               if pending_forward_info.onion_packet.is_some() { // If short_channel_id is 0 here, we'll reject them in the body here
+                       let forwarding_id = match channel_state.short_to_id.get(&pending_forward_info.short_channel_id) {
                                None => {
                                        return Err(HandleError{err: "Don't have available channel for forwarding as requested.",
                                                msg: Some(msgs::ErrorMessage::UpdateFailHTLC {
@@ -1016,7 +1165,7 @@ impl ChannelMessageHandler for ChannelManager {
                                },
                                Some(id) => id.clone(),
                        };
-                       let chan = channels.by_id.get_mut(&forwarding_id).unwrap();
+                       let chan = channel_state.by_id.get_mut(&forwarding_id).unwrap();
                        if !chan.is_live() {
                                let chan_update = self.get_channel_update(chan).unwrap();
                                return Err(HandleError{err: "Forwarding channel is not in a ready state.",
@@ -1031,7 +1180,37 @@ impl ChannelMessageHandler for ChannelManager {
                        }
                }
 
-               match channels.by_id.get_mut(&msg.channel_id) {
+               let claimable_htlcs_entry = channel_state.claimable_htlcs.entry(msg.payment_hash.clone());
+
+               // We dont correctly handle payments that route through us twice on their way to their
+               // destination. That's OK since those nodes are probably busted or trying to do network
+               // mapping through repeated loops. In either case, we want them to stop talking to us, so
+               // we send permanent_node_failure.
+               match &claimable_htlcs_entry {
+                       &hash_map::Entry::Occupied(ref e) => {
+                               let mut acceptable_cycle = false;
+                               match e.get() {
+                                       &PendingOutboundHTLC::OutboundRoute { .. } => {
+                                               acceptable_cycle = pending_forward_info.short_channel_id == 0;
+                                       },
+                                       _ => {},
+                               }
+                               if !acceptable_cycle {
+                                       return Err(HandleError{err: "Payment looped through us twice",
+                                               msg: Some(msgs::ErrorMessage::UpdateFailHTLC {
+                                                       msg: msgs::UpdateFailHTLC {
+                                                               channel_id: msg.channel_id,
+                                                               htlc_id: msg.htlc_id,
+                                                               reason: ChannelManager::build_first_hop_failure_packet(&shared_secret, 0x4000 | 0x2000|2, &[0;0]),
+                                                       }
+                                               }),
+                                       });
+                               }
+                       },
+                       _ => {},
+               }
+
+               let (source_short_channel_id, res) = match channel_state.by_id.get_mut(&msg.channel_id) {
                        Some(chan) => {
                                if chan.get_their_node_id() != *their_node_id {
                                        return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -1039,17 +1218,43 @@ impl ChannelMessageHandler for ChannelManager {
                                if !chan.is_usable() {
                                        return Err(HandleError{err: "Channel not yet available for receiving HTLCs", msg: None});
                                }
-                               pending_forward_info.prev_short_channel_id = chan.get_short_channel_id().unwrap();
-                               chan.update_add_htlc(&msg, pending_forward_info)
+                               let short_channel_id = chan.get_short_channel_id().unwrap();
+                               pending_forward_info.prev_short_channel_id = short_channel_id;
+                               (short_channel_id, chan.update_add_htlc(&msg, pending_forward_info)?)
                        },
                        None => return Err(HandleError{err: "Failed to find corresponding channel", msg: None}), //TODO: panic?
+               };
+
+               match claimable_htlcs_entry {
+                       hash_map::Entry::Occupied(mut e) => {
+                               let mut outbound_route = e.get_mut();
+                               let route = match outbound_route {
+                                       &mut PendingOutboundHTLC::OutboundRoute { ref route } => {
+                                               route.clone()
+                                       },
+                                       _ => { panic!("WAT") },
+                               };
+                               *outbound_route = PendingOutboundHTLC::CycledRoute {
+                                       source_short_channel_id,
+                                       incoming_packet_shared_secret: shared_secret,
+                                       route
+                               };
+                       },
+                       hash_map::Entry::Vacant(e) => {
+                               e.insert(PendingOutboundHTLC::IntermediaryHopData {
+                                       source_short_channel_id,
+                                       incoming_packet_shared_secret: shared_secret,
+                               });
+                       }
                }
+
+               Ok(res)
        }
 
        fn handle_update_fulfill_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFulfillHTLC) -> Result<Option<(Vec<msgs::UpdateAddHTLC>, msgs::CommitmentSigned)>, HandleError> {
                let res = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.get_mut(&msg.channel_id) {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.get_mut(&msg.channel_id) {
                                Some(chan) => {
                                        if chan.get_their_node_id() != *their_node_id {
                                                return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -1060,41 +1265,50 @@ impl ChannelMessageHandler for ChannelManager {
                        }
                };
                //TODO: Delay the claimed_funds relaying just like we do outbound relay!
-               self.claim_funds(msg.payment_preimage.clone());
+               self.claim_funds_internal(msg.payment_preimage.clone(), false);
                res
        }
 
        fn handle_update_fail_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFailHTLC) -> Result<Option<(Vec<msgs::UpdateAddHTLC>, msgs::CommitmentSigned)>, HandleError> {
-               let mut channels = self.channels.lock().unwrap();
-               match channels.by_id.get_mut(&msg.channel_id) {
-                       Some(chan) => {
-                               if chan.get_their_node_id() != *their_node_id {
-                                       return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
-                               }
-                               chan.update_fail_htlc(&msg)
-                       },
-                       None => return Err(HandleError{err: "Failed to find corresponding channel", msg: None})
-               }
-               //TODO Pass the reason backwards through the onion channel
+               let res = {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.get_mut(&msg.channel_id) {
+                               Some(chan) => {
+                                       if chan.get_their_node_id() != *their_node_id {
+                                               return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
+                                       }
+                                       chan.update_fail_htlc(&msg)?
+                               },
+                               None => return Err(HandleError{err: "Failed to find corresponding channel", msg: None})
+                       }
+               };
+               self.fail_htlc_backwards_internal(&res.0, HTLCFailReason::ErrorPacket { err: &msg.reason });
+               Ok(res.1)
        }
 
        fn handle_update_fail_malformed_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFailMalformedHTLC) -> Result<Option<(Vec<msgs::UpdateAddHTLC>, msgs::CommitmentSigned)>, HandleError> {
-               let mut channels = self.channels.lock().unwrap();
-               match channels.by_id.get_mut(&msg.channel_id) {
-                       Some(chan) => {
-                               if chan.get_their_node_id() != *their_node_id {
-                                       return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
-                               }
-                               chan.update_fail_malformed_htlc(&msg)
-                       },
-                       None => return Err(HandleError{err: "Failed to find corresponding channel", msg: None})
-               }
+               let res = {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.get_mut(&msg.channel_id) {
+                               Some(chan) => {
+                                       if chan.get_their_node_id() != *their_node_id {
+                                               return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
+                                       }
+                                       chan.update_fail_malformed_htlc(&msg)?
+                               },
+                               None => return Err(HandleError{err: "Failed to find corresponding channel", msg: None})
+                       }
+               };
+               self.fail_htlc_backwards_internal(&res.0, HTLCFailReason::Reason { failure_code: msg.failure_code });
+               Ok(res.1)
        }
 
        fn handle_commitment_signed(&self, their_node_id: &PublicKey, msg: &msgs::CommitmentSigned) -> Result<msgs::RevokeAndACK, HandleError> {
-               let ((res, mut forwarding_infos), monitor) = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.get_mut(&msg.channel_id) {
+               let mut forward_event = None;
+               let (res, monitor) = {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+
+                       let ((res, mut forwarding_infos), monitor) = match channel_state.by_id.get_mut(&msg.channel_id) {
                                Some(chan) => {
                                        if chan.get_their_node_id() != *their_node_id {
                                                return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -1102,21 +1316,15 @@ impl ChannelMessageHandler for ChannelManager {
                                        (chan.commitment_signed(&msg)?, chan.channel_monitor())
                                },
                                None => return Err(HandleError{err: "Failed to find corresponding channel", msg: None})
-                       }
-               };
-               //TODO: Only if we store HTLC sigs
-               self.monitor.add_update_monitor(monitor.get_funding_txo().unwrap(), monitor)?;
+                       };
 
-               let mut forward_event = None;
-               {
-                       let mut pending_htlcs = self.pending_htlcs_forwardable.lock().unwrap();
-                       if pending_htlcs.forward_htlcs.is_empty() {
+                       if channel_state.forward_htlcs.is_empty() {
                                let mut rng = thread_rng();
                                forward_event = Some(Instant::now() + Duration::from_millis(((rng.next_f32() * 4.0 + 1.0) * MIN_HTLC_RELAY_HOLDING_CELL_MILLIS as f32) as u64));
-                               pending_htlcs.next_forward = forward_event.unwrap();
+                               channel_state.next_forward = forward_event.unwrap();
                        }
                        for forward_info in forwarding_infos.drain(..) {
-                               match pending_htlcs.forward_htlcs.entry(forward_info.short_channel_id) {
+                               match channel_state.forward_htlcs.entry(forward_info.short_channel_id) {
                                        hash_map::Entry::Occupied(mut entry) => {
                                                entry.get_mut().push(forward_info);
                                        },
@@ -1125,7 +1333,12 @@ impl ChannelMessageHandler for ChannelManager {
                                        }
                                }
                        }
-               }
+
+                       (res, monitor)
+               };
+               //TODO: Only if we store HTLC sigs
+               self.monitor.add_update_monitor(monitor.get_funding_txo().unwrap(), monitor)?;
+
                match forward_event {
                        Some(time) => {
                                let mut pending_events = self.pending_events.lock().unwrap();
@@ -1141,8 +1354,8 @@ impl ChannelMessageHandler for ChannelManager {
 
        fn handle_revoke_and_ack(&self, their_node_id: &PublicKey, msg: &msgs::RevokeAndACK) -> Result<(), HandleError> {
                let monitor = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.get_mut(&msg.channel_id) {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.get_mut(&msg.channel_id) {
                                Some(chan) => {
                                        if chan.get_their_node_id() != *their_node_id {
                                                return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -1158,8 +1371,8 @@ impl ChannelMessageHandler for ChannelManager {
        }
 
        fn handle_update_fee(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFee) -> Result<(), HandleError> {
-               let mut channels = self.channels.lock().unwrap();
-               match channels.by_id.get_mut(&msg.channel_id) {
+               let mut channel_state = self.channel_state.lock().unwrap();
+               match channel_state.by_id.get_mut(&msg.channel_id) {
                        Some(chan) => {
                                if chan.get_their_node_id() != *their_node_id {
                                        return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -1172,8 +1385,8 @@ impl ChannelMessageHandler for ChannelManager {
 
        fn handle_announcement_signatures(&self, their_node_id: &PublicKey, msg: &msgs::AnnouncementSignatures) -> Result<(), HandleError> {
                let (chan_announcement, chan_update) = {
-                       let mut channels = self.channels.lock().unwrap();
-                       match channels.by_id.get_mut(&msg.channel_id) {
+                       let mut channel_state = self.channel_state.lock().unwrap();
+                       match channel_state.by_id.get_mut(&msg.channel_id) {
                                Some(chan) => {
                                        if chan.get_their_node_id() != *their_node_id {
                                                return Err(HandleError{err: "Got a message for a channel from the wrong node!", msg: None})
@@ -1514,25 +1727,19 @@ mod tests {
        }
 
        static mut PAYMENT_COUNT: u8 = 0;
-       fn send_payment(origin_node: &ChannelManager, origin_router: &Router, expected_route: &[&ChannelManager]) {
-               let route = origin_router.get_route(&expected_route.last().unwrap().get_our_node_id(), &Vec::new(), 1000000, 142).unwrap();
-               assert_eq!(route.hops.len(), expected_route.len());
-               for (node, hop) in expected_route.iter().zip(route.hops.iter()) {
-                       assert_eq!(hop.pubkey, node.get_our_node_id());
-               }
-
-               let payment_preimage = unsafe { [PAYMENT_COUNT; 32] };
+       fn send_along_route(origin_node: &ChannelManager, route: Route, expected_route: &[&ChannelManager], recv_value: u64) -> ([u8; 32], [u8; 32]) {
+               let our_payment_preimage = unsafe { [PAYMENT_COUNT; 32] };
                unsafe { PAYMENT_COUNT += 1 };
                let our_payment_hash = {
                        let mut sha = Sha256::new();
-                       sha.input(&payment_preimage[..]);
+                       sha.input(&our_payment_preimage[..]);
                        let mut ret = [0; 32];
                        sha.result(&mut ret);
                        ret
                };
 
                let mut payment_event = {
-                       let msgs = origin_node.send_payment(&route, our_payment_hash).unwrap().unwrap();
+                       let msgs = origin_node.send_payment(route, our_payment_hash).unwrap().unwrap();
                        SendEvent {
                                node_id: expected_route[0].get_our_node_id(),
                                msgs: vec!(msgs.0),
@@ -1555,7 +1762,7 @@ mod tests {
                                _ => panic!("Unexpected event"),
                        };
 
-                       node.pending_htlcs_forwardable.lock().unwrap().next_forward = Instant::now();
+                       node.channel_state.lock().unwrap().next_forward = Instant::now();
                        node.process_pending_htlc_forward();
 
                        let mut events_2 = node.get_and_clear_pending_events();
@@ -1564,7 +1771,7 @@ mod tests {
                                match events_2[0] {
                                        Event::PaymentReceived { ref payment_hash, amt } => {
                                                assert_eq!(our_payment_hash, *payment_hash);
-                                               assert_eq!(amt, 1000000);
+                                               assert_eq!(amt, recv_value);
                                        },
                                        _ => panic!("Unexpected event"),
                                }
@@ -1578,7 +1785,19 @@ mod tests {
                        prev_node = node;
                }
 
-               assert!(expected_route.last().unwrap().claim_funds(payment_preimage));
+               (our_payment_preimage, our_payment_hash)
+       }
+
+       fn send_payment(origin_node: &ChannelManager, origin_router: &Router, expected_route: &[&ChannelManager], recv_value: u64) {
+               let route = origin_router.get_route(&expected_route.last().unwrap().get_our_node_id(), &Vec::new(), recv_value, 142).unwrap();
+               assert_eq!(route.hops.len(), expected_route.len());
+               for (node, hop) in expected_route.iter().zip(route.hops.iter()) {
+                       assert_eq!(hop.pubkey, node.get_our_node_id());
+               }
+
+               let our_payment_preimage = send_along_route(origin_node, route, expected_route, recv_value).0;
+
+               assert!(expected_route.last().unwrap().claim_funds(our_payment_preimage));
 
                let mut expected_next_node = expected_route.last().unwrap().get_our_node_id();
                let mut prev_node = expected_route.last().unwrap();
@@ -1606,6 +1825,62 @@ mod tests {
 
                assert_eq!(expected_next_node, origin_node.get_our_node_id());
                assert!(origin_node.handle_update_fulfill_htlc(&expected_route.first().unwrap().get_our_node_id(), &next_msg.unwrap()).unwrap().is_none());
+
+               let events = origin_node.get_and_clear_pending_events();
+               assert_eq!(events.len(), 1);
+               match events[0] {
+                       Event::PaymentSent { payment_preimage } => {
+                               assert_eq!(payment_preimage, our_payment_preimage);
+                       },
+                       _ => panic!("Unexpected event"),
+               }
+       }
+
+       fn send_failed_payment(origin_node: &ChannelManager, origin_router: &Router, expected_route: &[&ChannelManager]) {
+               let route = origin_router.get_route(&expected_route.last().unwrap().get_our_node_id(), &Vec::new(), 1000000, 142).unwrap();
+               assert_eq!(route.hops.len(), expected_route.len());
+               for (node, hop) in expected_route.iter().zip(route.hops.iter()) {
+                       assert_eq!(hop.pubkey, node.get_our_node_id());
+               }
+               let our_payment_hash = send_along_route(origin_node, route, expected_route, 1000000).1;
+
+               assert!(expected_route.last().unwrap().fail_htlc_backwards(&our_payment_hash));
+
+               let mut expected_next_node = expected_route.last().unwrap().get_our_node_id();
+               let mut prev_node = expected_route.last().unwrap();
+               let mut next_msg = None;
+               for node in expected_route.iter().rev() {
+                       assert_eq!(expected_next_node, node.get_our_node_id());
+                       match next_msg {
+                               Some(msg) => {
+                                       assert!(node.handle_update_fail_htlc(&prev_node.get_our_node_id(), &msg).unwrap().is_none());
+                               }, None => {}
+                       }
+
+                       let events = node.get_and_clear_pending_events();
+                       assert_eq!(events.len(), 1);
+                       match events[0] {
+                               Event::SendFailHTLC { ref node_id, ref msg } => {
+                                       expected_next_node = node_id.clone();
+                                       next_msg = Some(msg.clone());
+                               },
+                               _ => panic!("Unexpected event"),
+                       };
+
+                       prev_node = node;
+               }
+
+               assert_eq!(expected_next_node, origin_node.get_our_node_id());
+               assert!(origin_node.handle_update_fail_htlc(&expected_route.first().unwrap().get_our_node_id(), &next_msg.unwrap()).unwrap().is_none());
+
+               let events = origin_node.get_and_clear_pending_events();
+               assert_eq!(events.len(), 1);
+               match events[0] {
+                       Event::PaymentFailed { payment_hash } => {
+                               assert_eq!(payment_hash, our_payment_hash);
+                       },
+                       _ => panic!("Unexpected event"),
+               }
        }
 
        #[test]
@@ -1680,9 +1955,13 @@ mod tests {
                }
 
                // Send some payments
-               send_payment(&node_1, &router_1, &vec!(&*node_2, &*node_3, &*node_4)[..]);
-               send_payment(&node_2, &router_2, &vec!(&*node_3, &*node_4)[..]);
-               send_payment(&node_4, &router_4, &vec!(&*node_3, &*node_2, &*node_1)[..]);
+               send_payment(&node_1, &router_1, &vec!(&*node_2, &*node_3, &*node_4)[..], 1000000);
+               send_payment(&node_2, &router_2, &vec!(&*node_3, &*node_4)[..], 1000000);
+               send_payment(&node_4, &router_4, &vec!(&*node_3, &*node_2, &*node_1)[..], 1000000);
+               send_payment(&node_4, &router_4, &vec!(&*node_3, &*node_2)[..], 250000);
+
+               // Test failure packets
+               send_failed_payment(&node_1, &router_1, &vec!(&*node_2, &*node_3, &*node_4)[..]);
 
                // Add a new channel that skips 3
                let chan_announcement_4 = create_chan_between_nodes(&node_2, &chain_monitor_2, &node_4, &chain_monitor_4);
@@ -1692,7 +1971,31 @@ mod tests {
                        router.handle_channel_update(&chan_announcement_4.2).unwrap();
                }
 
-               send_payment(&node_1, &router_1, &vec!(&*node_2, &*node_4)[..]);
+               send_payment(&node_1, &router_1, &vec!(&*node_2, &*node_4)[..], 1000000);
+
+               // Rebalance a bit
+               let mut hops = Vec::with_capacity(3);
+               hops.push(RouteHop {
+                       pubkey: node_3.get_our_node_id(),
+                       short_channel_id: chan_announcement_2.1.contents.short_channel_id,
+                       fee_msat: 0,
+                       cltv_expiry_delta: chan_announcement_3.1.contents.cltv_expiry_delta as u32
+               });
+               hops.push(RouteHop {
+                       pubkey: node_4.get_our_node_id(),
+                       short_channel_id: chan_announcement_3.1.contents.short_channel_id,
+                       fee_msat: 0,
+                       cltv_expiry_delta: chan_announcement_4.2.contents.cltv_expiry_delta as u32
+               });
+               hops.push(RouteHop {
+                       pubkey: node_2.get_our_node_id(),
+                       short_channel_id: chan_announcement_4.1.contents.short_channel_id,
+                       fee_msat: 250000,
+                       cltv_expiry_delta: 142,
+               });
+               hops[1].fee_msat = chan_announcement_4.2.contents.fee_base_msat as u64 + chan_announcement_4.2.contents.fee_proportional_millionths as u64 * hops[2].fee_msat as u64 / 1000000;
+               hops[0].fee_msat = chan_announcement_3.1.contents.fee_base_msat as u64 + chan_announcement_3.1.contents.fee_proportional_millionths as u64 * hops[1].fee_msat as u64 / 1000000;
+               send_along_route(&node_2, Route { hops }, &vec!(&*node_3, &*node_4, &*node_2)[..], 250000);
 
                // Check that we processed all pending events
                for node in vec!(&node_1, &node_2, &node_3, &node_4) {
index 3c56aa120ec43fb974c25c80c099411bd1f6c66e..3cdd4c77cb0efbd198b2c1ef782186e488088a6f 100644 (file)
@@ -205,12 +205,14 @@ pub struct UpdateFulfillHTLC {
        pub payment_preimage: [u8; 32],
 }
 
+#[derive(Clone)]
 pub struct UpdateFailHTLC {
        pub channel_id: Uint256,
        pub htlc_id: u64,
        pub reason: OnionErrorPacket,
 }
 
+#[derive(Clone)]
 pub struct UpdateFailMalformedHTLC {
        pub channel_id: Uint256,
        pub htlc_id: u64,
@@ -337,6 +339,9 @@ pub struct HandleError { //TODO: rename me
        pub msg: Option<ErrorMessage>, //TODO: Move into an Action enum and require it!
 }
 
+/// A trait to describe an object which can receive channel messages. Messages MAY be called in
+/// paralell when they originate from different their_node_ids, however they MUST NOT be called in
+/// paralell when the two calls have the same their_node_id.
 pub trait ChannelMessageHandler : events::EventsProvider {
        //Channel init:
        fn handle_open_channel(&self, their_node_id: &PublicKey, msg: &OpenChannel) -> Result<AcceptChannel, HandleError>;
@@ -399,6 +404,7 @@ pub struct DecodedOnionErrorPacket {
        pub pad: Vec<u8>,
 }
 
+#[derive(Clone)]
 pub struct OnionErrorPacket {
        // This really should be a constant size slice, but the spec lets these things be up to 128KB?
        // (TODO) We limit it in decode to much lower...
index 3a0d6b66d3578135dbe050cb936d74893b74215c..2b60bbf122bce3af47a16997afe48740ede9805a 100644 (file)
@@ -502,6 +502,8 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                                        Event::FundingGenerationReady {..} => { /* Hand upstream */ },
                                        Event::FundingBroadcastSafe {..} => { /* Hand upstream */ },
                                        Event::PaymentReceived {..} => { /* Hand upstream */ },
+                                       Event::PaymentSent {..} => { /* Hand upstream */ },
+                                       Event::PaymentFailed {..} => { /* Hand upstream */ },
 
                                        Event::PendingHTLCsForwardable {..} => {
                                                //TODO: Handle upstream in some confused form so that upstream just knows
@@ -547,6 +549,14 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                                                Self::do_attempt_write_data(&mut descriptor, peer);
                                                continue;
                                        },
+                                       Event::SendFailHTLC { ref node_id, ref msg } => {
+                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
+                                                               //TODO: Do whatever we're gonna do for handling dropped messages
+                                                       });
+                                               peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg, 131)));
+                                               Self::do_attempt_write_data(&mut descriptor, peer);
+                                               continue;
+                                       },
                                        Event::BroadcastChannelAnnouncement { ref msg, ref update_msg } => {
                                                let encoded_msg = encode_msg!(msg, 256);
                                                let encoded_update_msg = encode_msg!(update_msg, 258);
index 2419106fdd844e3b2bd357c02bc88b63c500cabf..75df79450f3507d80969ee0eb186a3a8022d28f6 100644 (file)
@@ -12,6 +12,7 @@ use std::collections::{HashMap,BinaryHeap};
 use std::collections::hash_map::Entry;
 
 /// A hop in a route
+#[derive(Clone)]
 pub struct RouteHop {
        pub pubkey: PublicKey,
        /// The channel that should be used from the previous hop to reach this node.
@@ -24,6 +25,7 @@ pub struct RouteHop {
 }
 
 /// A route from us through the network to a destination
+#[derive(Clone)]
 pub struct Route {
        /// The list of hops, NOT INCLUDING our own, where the last hop is the destination. Thus, this
        /// must always be at least length one. By protocol rules, this may not currently exceed 20 in
index 1bdc3682168ff73d4c567c286eca136f8158725c..9cf25ec38e15b23439d82a8f18c6c446352cb846 100644 (file)
@@ -30,10 +30,23 @@ pub enum Event {
        },
        /// Indicates we've received money! Just gotta dig out that payment preimage and feed it to
        /// ChannelManager::claim_funds to get it....
+       /// Note that if the preimage is not known, you must call ChannelManager::fail_htlc_backwards
+       /// to free up resources for this HTLC.
        PaymentReceived {
                payment_hash: [u8; 32],
                amt: u64,
        },
+       /// 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). payment_preimage serves as a payment receipt,
+       /// if you wish to have such a thing, you must store it somehow!
+       PaymentSent {
+               payment_preimage: [u8; 32],
+       },
+       /// Indicates an outbound payment we made failed. Probably some intermediary node dropped
+       /// something. You may wish to retry with a different route.
+       PaymentFailed {
+               payment_hash: [u8; 32],
+       },
 
        // Events indicating the network loop should send a message to a peer:
        /// Used to indicate that ChannelManager::process_pending_htlc_forwards should be called at a
@@ -64,6 +77,11 @@ pub enum Event {
                node_id: PublicKey,
                msg: msgs::UpdateFulfillHTLC,
        },
+       /// Used to indicate that we need to fail an htlc from the peer with the given node_id.
+       SendFailHTLC {
+               node_id: PublicKey,
+               msg: msgs::UpdateFailHTLC,
+       },
        /// Used to indicate that a channel_announcement and channel_update should be broadcast to all
        /// peers (except the peer with node_id either msg.contents.node_id_1 or msg.contents.node_id_2).
        BroadcastChannelAnnouncement {