Clarify the in-flight HTLC state-tracking structs a bit.
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 60fe1c4586eb89471113ffe0c8ed6ae97fb90897..b73f8667073bac64abdb11fd9e2f7e81fbb07c7e 100644 (file)
@@ -30,26 +30,26 @@ use chain::transaction::OutPoint;
 use ln::channel::{Channel, ChannelError};
 use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdateErr, ManyChannelMonitor, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY};
 use ln::router::Route;
-use ln::features::InitFeatures;
+use ln::features::{InitFeatures, NodeFeatures};
 use ln::msgs;
 use ln::onion_utils;
 use ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
-use chain::keysinterface::{ChannelKeys, KeysInterface};
+use chain::keysinterface::{ChannelKeys, KeysInterface, InMemoryChannelKeys};
 use util::config::UserConfig;
 use util::{byte_utils, events};
 use util::ser::{Readable, ReadableArgs, Writeable, Writer};
-use util::chacha20::ChaCha20;
+use util::chacha20::{ChaCha20, ChaChaReader};
 use util::logger::Logger;
 use util::errors::APIError;
 
 use std::{cmp, mem};
 use std::collections::{HashMap, hash_map, HashSet};
-use std::io::Cursor;
+use std::io::{Cursor, Read};
 use std::sync::{Arc, Mutex, MutexGuard, RwLock};
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::time::Duration;
-
-const SIXTY_FIVE_ZEROS: [u8; 65] = [0; 65];
+use std::marker::{Sync, Send};
+use std::ops::Deref;
 
 // We hold various information about HTLC relay in the HTLC objects in Channel itself:
 //
@@ -57,15 +57,19 @@ const SIXTY_FIVE_ZEROS: [u8; 65] = [0; 65];
 // forward the HTLC with information it will give back to us when it does so, or if it should Fail
 // the HTLC with the relevant message for the Channel to handle giving to the remote peer.
 //
-// When a Channel forwards an HTLC to its peer, it will give us back the PendingForwardHTLCInfo
-// which we will use to construct an outbound HTLC, with a relevant HTLCSource::PreviousHopData
-// filled in to indicate where it came from (which we can use to either fail-backwards or fulfill
-// the HTLC backwards along the relevant path).
+// Once said HTLC is committed in the Channel, if the PendingHTLCStatus indicated Forward, the
+// Channel will return the PendingHTLCInfo back to us, and we will create an HTLCForwardInfo
+// with it to track where it came from (in case of onwards-forward error), waiting a random delay
+// before we forward it.
+//
+// We will then use HTLCForwardInfo's PendingHTLCInfo to construct an outbound HTLC, with a
+// relevant HTLCSource::PreviousHopData filled in to indicate where it came from (which we can use
+// to either fail-backwards or fulfill the HTLC backwards along the relevant path).
 // Alternatively, we can fill an outbound HTLC with a HTLCSource::OutboundRoute indicating this is
 // our payment, which we can use to decode errors or inform the user that the payment was sent.
-/// Stores the info we will need to send when we want to forward an HTLC onwards
+
 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
-pub(super) struct PendingForwardHTLCInfo {
+pub(super) struct PendingHTLCInfo {
        onion_packet: Option<msgs::OnionPacket>,
        incoming_shared_secret: [u8; 32],
        payment_hash: PaymentHash,
@@ -83,10 +87,22 @@ pub(super) enum HTLCFailureMsg {
 /// Stores whether we can't forward an HTLC or relevant forwarding info
 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 pub(super) enum PendingHTLCStatus {
-       Forward(PendingForwardHTLCInfo),
+       Forward(PendingHTLCInfo),
        Fail(HTLCFailureMsg),
 }
 
+pub(super) enum HTLCForwardInfo {
+       AddHTLC {
+               prev_short_channel_id: u64,
+               prev_htlc_id: u64,
+               forward_info: PendingHTLCInfo,
+       },
+       FailHTLC {
+               htlc_id: u64,
+               err_packet: msgs::OnionErrorPacket,
+       },
+}
+
 /// Tracks the inbound corresponding to an outbound HTLC
 #[derive(Clone, PartialEq)]
 pub(super) struct HTLCPreviousHopData {
@@ -231,18 +247,6 @@ impl MsgHandleErrInternal {
 /// second to 30 seconds, but people expect lightning to be, you know, kinda fast, sadly.
 const MIN_HTLC_RELAY_HOLDING_CELL_MILLIS: u64 = 100;
 
-pub(super) enum HTLCForwardInfo {
-       AddHTLC {
-               prev_short_channel_id: u64,
-               prev_htlc_id: u64,
-               forward_info: PendingForwardHTLCInfo,
-       },
-       FailHTLC {
-               htlc_id: u64,
-               err_packet: msgs::OnionErrorPacket,
-       },
-}
-
 /// For events which result in both a RevokeAndACK and a CommitmentUpdate, by default they should
 /// be sent in the order they appear in the return value, however sometimes the order needs to be
 /// variable at runtime (eg Channel::channel_reestablish needs to re-send messages in the order
@@ -262,7 +266,7 @@ pub(super) struct ChannelHolder<ChanSigner: ChannelKeys> {
        /// short channel id -> forward infos. Key of 0 means payments received
        /// Note that while this is held in the same mutex as the channels themselves, no consistency
        /// guarantees are made about the existence of a channel with the short id here, nor the short
-       /// ids in the PendingForwardHTLCInfo!
+       /// ids in the PendingHTLCInfo!
        pub(super) forward_htlcs: HashMap<u64, Vec<HTLCForwardInfo>>,
        /// payment_hash -> Vec<(amount_received, htlc_source)> for tracking things that were to us and
        /// can be failed/claimed by the user
@@ -275,9 +279,30 @@ pub(super) struct ChannelHolder<ChanSigner: ChannelKeys> {
        pub(super) pending_msg_events: Vec<events::MessageSendEvent>,
 }
 
+/// State we hold per-peer. In the future we should put channels in here, but for now we only hold
+/// the latest Init features we heard from the peer.
+struct PeerState {
+       latest_features: InitFeatures,
+}
+
 #[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
 const ERR: () = "You need at least 32 bit pointers (well, usize, but we'll assume they're the same) for ChannelManager::latest_block_height";
 
+/// 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
+/// SimpleRefChannelManager is the more appropriate type. Defining these type aliases prevents
+/// issues such as overly long function definitions.
+pub type SimpleArcChannelManager<M> = Arc<ChannelManager<InMemoryChannelKeys, Arc<M>>>;
+
+/// SimpleRefChannelManager is a type alias for a ChannelManager reference, and is the reference
+/// counterpart to the SimpleArcChannelManager type alias. Use this type by default when you don't
+/// need a ChannelManager with a static lifetime. You'll need a static lifetime in cases such as
+/// usage of lightning-net-tokio (since tokio::spawn requires parameters with static lifetimes).
+/// But if this is not necessary, using a reference is more efficient. Defining these type aliases
+/// helps with issues such as long function definitions.
+pub type SimpleRefChannelManager<'a, M> = ChannelManager<InMemoryChannelKeys, &'a M>;
+
 /// Manager which keeps track of a number of channels and sends messages to the appropriate
 /// channel, also tracking HTLC preimages and forwarding onion packets appropriately.
 ///
@@ -307,12 +332,18 @@ const ERR: () = "You need at least 32 bit pointers (well, usize, but we'll assum
 /// ChannelUpdate messages informing peers that the channel is temporarily disabled. To avoid
 /// spam due to quick disconnection/reconnection, updates are not sent until the channel has been
 /// offline for a full minute. In order to track this, you must call
-/// timer_chan_freshness_every_min roughly once per minute, though it doesn't have to be perfec.
-pub struct ChannelManager<ChanSigner: ChannelKeys> {
+/// timer_chan_freshness_every_min roughly once per minute, though it doesn't have to be perfect.
+///
+/// Rather than using a plain ChannelManager, it is preferable to use either a SimpleArcChannelManager
+/// a SimpleRefChannelManager, for conciseness. See their documentation for more details, but
+/// essentially you should default to using a SimpleRefChannelManager, and use a
+/// SimpleArcChannelManager when you require a ChannelManager with a static lifetime, such as when
+/// you're using lightning-net-tokio.
+pub struct ChannelManager<ChanSigner: ChannelKeys, M: Deref> where M::Target: ManyChannelMonitor {
        default_configuration: UserConfig,
        genesis_hash: Sha256dHash,
        fee_estimator: Arc<FeeEstimator>,
-       monitor: Arc<ManyChannelMonitor>,
+       monitor: M,
        tx_broadcaster: Arc<BroadcasterInterface>,
 
        #[cfg(test)]
@@ -328,6 +359,16 @@ pub struct ChannelManager<ChanSigner: ChannelKeys> {
        channel_state: Mutex<ChannelHolder<ChanSigner>>,
        our_network_key: SecretKey,
 
+       last_node_announcement_serial: 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.
+       /// Because adding or removing an entry is rare, we usually take an outer read lock and then
+       /// operate on the inner value freely. Sadly, this prevents parallel operation when opening a
+       /// new channel.
+       per_peer_state: RwLock<HashMap<PublicKey, Mutex<PeerState>>>,
+
        pending_events: Mutex<Vec<events::Event>>,
        /// Used when we have to take a BIG lock to make sure everything is self-consistent.
        /// Essentially just when we're serializing ourselves out.
@@ -390,6 +431,10 @@ pub struct ChannelDetails {
        pub short_channel_id: Option<u64>,
        /// The node_id of our counterparty
        pub remote_network_id: PublicKey,
+       /// The Features the channel counterparty provided upon last connection.
+       /// Useful for routing as it is the most up-to-date copy of the counterparty's features and
+       /// many routing-relevant features are present in the init context.
+       pub counterparty_features: InitFeatures,
        /// The value, in satoshis, of this channel as appears in the funding output
        pub channel_value_satoshis: u64,
        /// The user_id passed in to create_channel, or 0 if the channel was inbound.
@@ -532,7 +577,7 @@ macro_rules! handle_monitor_err {
                                                        } else if $resend_commitment { "commitment" }
                                                        else if $resend_raa { "RAA" }
                                                        else { "nothing" },
-                                               (&$failed_forwards as &Vec<(PendingForwardHTLCInfo, u64)>).len(),
+                                               (&$failed_forwards as &Vec<(PendingHTLCInfo, u64)>).len(),
                                                (&$failed_fails as &Vec<(HTLCSource, PaymentHash, HTLCFailReason)>).len());
                                if !$resend_commitment {
                                        debug_assert!($action_type == RAACommitmentOrder::RevokeAndACKFirst || !$resend_raa);
@@ -568,7 +613,7 @@ macro_rules! maybe_break_monitor_err {
        }
 }
 
-impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref> ChannelManager<ChanSigner, M> where M::Target: ManyChannelMonitor {
        /// Constructs a new ChannelManager to hold several channels and route between them.
        ///
        /// This is the main "logic hub" for all channel-related actions, and implements
@@ -587,14 +632,14 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
        /// the ChannelManager as a listener to the BlockNotifier and call the BlockNotifier's
        /// `block_(dis)connected` methods, which will notify all registered listeners in one
        /// go.
-       pub fn new(network: Network, feeest: Arc<FeeEstimator>, monitor: Arc<ManyChannelMonitor>, tx_broadcaster: Arc<BroadcasterInterface>, logger: Arc<Logger>,keys_manager: Arc<KeysInterface<ChanKeySigner = ChanSigner>>, config: UserConfig, current_blockchain_height: usize) -> Result<Arc<ChannelManager<ChanSigner>>, secp256k1::Error> {
+       pub fn new(network: Network, feeest: Arc<FeeEstimator>, monitor: M, tx_broadcaster: Arc<BroadcasterInterface>, logger: Arc<Logger>,keys_manager: Arc<KeysInterface<ChanKeySigner = ChanSigner>>, config: UserConfig, current_blockchain_height: usize) -> Result<ChannelManager<ChanSigner, M>, secp256k1::Error> {
                let secp_ctx = Secp256k1::new();
 
-               let res = Arc::new(ChannelManager {
+               let res = ChannelManager {
                        default_configuration: config.clone(),
                        genesis_hash: genesis_block(network).header.bitcoin_hash(),
                        fee_estimator: feeest.clone(),
-                       monitor: monitor.clone(),
+                       monitor,
                        tx_broadcaster,
 
                        latest_block_height: AtomicUsize::new(current_blockchain_height),
@@ -610,13 +655,17 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                        }),
                        our_network_key: keys_manager.get_node_secret(),
 
+                       last_node_announcement_serial: AtomicUsize::new(0),
+
+                       per_peer_state: RwLock::new(HashMap::new()),
+
                        pending_events: Mutex::new(Vec::new()),
                        total_consistency_lock: RwLock::new(()),
 
                        keys_manager,
 
                        logger,
-               });
+               };
 
                Ok(res)
        }
@@ -660,56 +709,53 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                Ok(())
        }
 
-       /// Gets the list of open channels, in random order. See ChannelDetail field documentation for
-       /// more information.
-       pub fn list_channels(&self) -> Vec<ChannelDetails> {
-               let channel_state = self.channel_state.lock().unwrap();
-               let mut res = Vec::with_capacity(channel_state.by_id.len());
-               for (channel_id, channel) in channel_state.by_id.iter() {
-                       let (inbound_capacity_msat, outbound_capacity_msat) = channel.get_inbound_outbound_available_balance_msat();
-                       res.push(ChannelDetails {
-                               channel_id: (*channel_id).clone(),
-                               short_channel_id: channel.get_short_channel_id(),
-                               remote_network_id: channel.get_their_node_id(),
-                               channel_value_satoshis: channel.get_value_satoshis(),
-                               inbound_capacity_msat,
-                               outbound_capacity_msat,
-                               user_id: channel.get_user_id(),
-                               is_live: channel.is_live(),
-                       });
-               }
-               res
-       }
-
-       /// Gets the list of usable channels, in random order. Useful as an argument to
-       /// Router::get_route to ensure non-announced channels are used.
-       ///
-       /// These are guaranteed to have their is_live value set to true, see the documentation for
-       /// ChannelDetails::is_live for more info on exactly what the criteria are.
-       pub fn list_usable_channels(&self) -> Vec<ChannelDetails> {
-               let channel_state = self.channel_state.lock().unwrap();
-               let mut res = Vec::with_capacity(channel_state.by_id.len());
-               for (channel_id, channel) in channel_state.by_id.iter() {
-                       // Note we use is_live here instead of usable which leads to somewhat confused
-                       // internal/external nomenclature, but that's ok cause that's probably what the user
-                       // really wanted anyway.
-                       if channel.is_live() {
+       fn list_channels_with_filter<F: FnMut(&(&[u8; 32], &Channel<ChanSigner>)) -> bool>(&self, f: F) -> Vec<ChannelDetails> {
+               let mut res = Vec::new();
+               {
+                       let channel_state = self.channel_state.lock().unwrap();
+                       res.reserve(channel_state.by_id.len());
+                       for (channel_id, channel) in channel_state.by_id.iter().filter(f) {
                                let (inbound_capacity_msat, outbound_capacity_msat) = channel.get_inbound_outbound_available_balance_msat();
                                res.push(ChannelDetails {
                                        channel_id: (*channel_id).clone(),
                                        short_channel_id: channel.get_short_channel_id(),
                                        remote_network_id: channel.get_their_node_id(),
+                                       counterparty_features: InitFeatures::empty(),
                                        channel_value_satoshis: channel.get_value_satoshis(),
                                        inbound_capacity_msat,
                                        outbound_capacity_msat,
                                        user_id: channel.get_user_id(),
-                                       is_live: true,
+                                       is_live: channel.is_live(),
                                });
                        }
                }
+               let per_peer_state = self.per_peer_state.read().unwrap();
+               for chan in res.iter_mut() {
+                       if let Some(peer_state) = per_peer_state.get(&chan.remote_network_id) {
+                               chan.counterparty_features = peer_state.lock().unwrap().latest_features.clone();
+                       }
+               }
                res
        }
 
+       /// Gets the list of open channels, in random order. See ChannelDetail field documentation for
+       /// more information.
+       pub fn list_channels(&self) -> Vec<ChannelDetails> {
+               self.list_channels_with_filter(|_| true)
+       }
+
+       /// Gets the list of usable channels, in random order. Useful as an argument to
+       /// Router::get_route to ensure non-announced channels are used.
+       ///
+       /// These are guaranteed to have their is_live value set to true, see the documentation for
+       /// ChannelDetails::is_live for more info on exactly what the criteria are.
+       pub fn list_usable_channels(&self) -> Vec<ChannelDetails> {
+               // Note we use is_live here instead of usable which leads to somewhat confused
+               // internal/external nomenclature, but that's ok cause that's probably what the user
+               // really wanted anyway.
+               self.list_channels_with_filter(|&(_, ref channel)| channel.is_live())
+       }
+
        /// Begins the process of closing a channel. After this call (plus some timeout), no new HTLCs
        /// will be accepted on the given channel, and after additional timeout/the closing of all
        /// pending HTLCs, the channel will be closed on chain.
@@ -866,22 +912,30 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                }
 
                let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
-               let next_hop_data = {
-                       let mut decoded = [0; 65];
-                       chacha.process(&msg.onion_routing_packet.hop_data[0..65], &mut decoded);
-                       match msgs::OnionHopData::read(&mut Cursor::new(&decoded[..])) {
+               let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&msg.onion_routing_packet.hop_data[..]) };
+               let (next_hop_data, next_hop_hmac) = {
+                       match msgs::OnionHopData::read(&mut chacha_stream) {
                                Err(err) => {
                                        let error_code = match err {
                                                msgs::DecodeError::UnknownVersion => 0x4000 | 1, // unknown realm byte
+                                               msgs::DecodeError::UnknownRequiredFeature|
+                                               msgs::DecodeError::InvalidValue|
+                                               msgs::DecodeError::ShortRead => 0x4000 | 22, // invalid_onion_payload
                                                _ => 0x2000 | 2, // Should never happen
                                        };
                                        return_err!("Unable to decode our hop data", error_code, &[0;0]);
                                },
-                               Ok(msg) => msg
+                               Ok(msg) => {
+                                       let mut hmac = [0; 32];
+                                       if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
+                                               return_err!("Unable to decode hop data", 0x4000 | 22, &[0;0]);
+                                       }
+                                       (msg, hmac)
+                               },
                        }
                };
 
-               let pending_forward_info = if next_hop_data.hmac == [0; 32] {
+               let pending_forward_info = if next_hop_hmac == [0; 32] {
                                #[cfg(test)]
                                {
                                        // In tests, make sure that the initial onion pcket data is, at least, non-0.
@@ -891,10 +945,11 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        // as-is (and were originally 0s).
                                        // Of course reverse path calculation is still pretty easy given naive routing
                                        // algorithms, but this fixes the most-obvious case.
-                                       let mut new_packet_data = [0; 19*65];
-                                       chacha.process(&msg.onion_routing_packet.hop_data[65..], &mut new_packet_data[0..19*65]);
-                                       assert_ne!(new_packet_data[0..65], [0; 65][..]);
-                                       assert_ne!(new_packet_data[..], [0; 19*65][..]);
+                                       let mut next_bytes = [0; 32];
+                                       chacha_stream.read_exact(&mut next_bytes).unwrap();
+                                       assert_ne!(next_bytes[..], [0; 32][..]);
+                                       chacha_stream.read_exact(&mut next_bytes).unwrap();
+                                       assert_ne!(next_bytes[..], [0; 32][..]);
                                }
 
                                // OUR PAYMENT!
@@ -903,11 +958,11 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        return_err!("The final CLTV expiry is too soon to handle", 17, &[0;0]);
                                }
                                // final_incorrect_htlc_amount
-                               if next_hop_data.data.amt_to_forward > msg.amount_msat {
+                               if next_hop_data.amt_to_forward > msg.amount_msat {
                                        return_err!("Upstream node sent less than we were supposed to receive in payment", 19, &byte_utils::be64_to_array(msg.amount_msat));
                                }
                                // final_incorrect_cltv_expiry
-                               if next_hop_data.data.outgoing_cltv_value != msg.cltv_expiry {
+                               if next_hop_data.outgoing_cltv_value != msg.cltv_expiry {
                                        return_err!("Upstream node set CLTV to the wrong value", 18, &byte_utils::be32_to_array(msg.cltv_expiry));
                                }
 
@@ -916,18 +971,29 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                // instead we stay symmetric with the forwarding case, only responding (after a
                                // delay) once they've send us a commitment_signed!
 
-                               PendingHTLCStatus::Forward(PendingForwardHTLCInfo {
+                               PendingHTLCStatus::Forward(PendingHTLCInfo {
                                        onion_packet: None,
                                        payment_hash: msg.payment_hash.clone(),
                                        short_channel_id: 0,
                                        incoming_shared_secret: shared_secret,
-                                       amt_to_forward: next_hop_data.data.amt_to_forward,
-                                       outgoing_cltv_value: next_hop_data.data.outgoing_cltv_value,
+                                       amt_to_forward: next_hop_data.amt_to_forward,
+                                       outgoing_cltv_value: next_hop_data.outgoing_cltv_value,
                                })
                        } else {
                                let mut new_packet_data = [0; 20*65];
-                               chacha.process(&msg.onion_routing_packet.hop_data[65..], &mut new_packet_data[0..19*65]);
-                               chacha.process(&SIXTY_FIVE_ZEROS[..], &mut new_packet_data[19*65..]);
+                               let read_pos = chacha_stream.read(&mut new_packet_data).unwrap();
+                               #[cfg(debug_assertions)]
+                               {
+                                       // Check two things:
+                                       // a) that the behavior of our stream here will return Ok(0) even if the TLV
+                                       //    read above emptied out our buffer and the unwrap() wont needlessly panic
+                                       // b) that we didn't somehow magically end up with extra data.
+                                       let mut t = [0; 1];
+                                       debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
+                               }
+                               // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
+                               // fill the onion hop data we'll forward to our next-hop peer.
+                               chacha_stream.chacha.process_in_place(&mut new_packet_data[read_pos..]);
 
                                let mut new_pubkey = msg.onion_routing_packet.public_key.unwrap();
 
@@ -946,21 +1012,29 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        version: 0,
                                        public_key,
                                        hop_data: new_packet_data,
-                                       hmac: next_hop_data.hmac.clone(),
+                                       hmac: next_hop_hmac.clone(),
                                };
 
-                               PendingHTLCStatus::Forward(PendingForwardHTLCInfo {
+                               let short_channel_id = match next_hop_data.format {
+                                       msgs::OnionHopDataFormat::Legacy { short_channel_id } => short_channel_id,
+                                       msgs::OnionHopDataFormat::NonFinalNode { short_channel_id } => short_channel_id,
+                                       msgs::OnionHopDataFormat::FinalNode => {
+                                               return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0;0]);
+                                       },
+                               };
+
+                               PendingHTLCStatus::Forward(PendingHTLCInfo {
                                        onion_packet: Some(outgoing_packet),
                                        payment_hash: msg.payment_hash.clone(),
-                                       short_channel_id: next_hop_data.data.short_channel_id,
+                                       short_channel_id: short_channel_id,
                                        incoming_shared_secret: shared_secret,
-                                       amt_to_forward: next_hop_data.data.amt_to_forward,
-                                       outgoing_cltv_value: next_hop_data.data.outgoing_cltv_value,
+                                       amt_to_forward: next_hop_data.amt_to_forward,
+                                       outgoing_cltv_value: next_hop_data.outgoing_cltv_value,
                                })
                        };
 
                channel_state = Some(self.channel_state.lock().unwrap());
-               if let &PendingHTLCStatus::Forward(PendingForwardHTLCInfo { ref onion_packet, ref short_channel_id, ref amt_to_forward, ref outgoing_cltv_value, .. }) = &pending_forward_info {
+               if let &PendingHTLCStatus::Forward(PendingHTLCInfo { ref onion_packet, ref short_channel_id, ref amt_to_forward, ref outgoing_cltv_value, .. }) = &pending_forward_info {
                        if onion_packet.is_some() { // If short_channel_id is 0 here, we'll reject them in the body here
                                let id_option = channel_state.as_ref().unwrap().short_to_id.get(&short_channel_id).cloned();
                                let forwarding_id = match id_option {
@@ -1097,6 +1171,9 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                let onion_keys = secp_call!(onion_utils::construct_onion_keys(&self.secp_ctx, &route, &session_priv),
                                APIError::RouteError{err: "Pubkey along hop was maliciously selected"});
                let (onion_payloads, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(&route, cur_height)?;
+               if onion_utils::route_size_insane(&onion_payloads) {
+                       return Err(APIError::RouteError{err: "Route had too large size once"});
+               }
                let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, prng_seed, &payment_hash);
 
                let _ = self.total_consistency_lock.read().unwrap();
@@ -1245,6 +1322,37 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                })
        }
 
+       /// Generates a signed node_announcement from the given arguments and creates a
+       /// BroadcastNodeAnnouncement event.
+       ///
+       /// RGB is a node "color" and alias a printable human-readable string to describe this node to
+       /// humans. They carry no in-protocol meaning.
+       ///
+       /// addresses represent the set (possibly empty) of socket addresses on which this node accepts
+       /// incoming connections.
+       pub fn broadcast_node_announcement(&self, rgb: [u8; 3], alias: [u8; 32], addresses: msgs::NetAddressSet) {
+               let _ = self.total_consistency_lock.read().unwrap();
+
+               let announcement = msgs::UnsignedNodeAnnouncement {
+                       features: NodeFeatures::supported(),
+                       timestamp: self.last_node_announcement_serial.fetch_add(1, Ordering::AcqRel) as u32,
+                       node_id: self.get_our_node_id(),
+                       rgb, alias,
+                       addresses: addresses.to_vec(),
+                       excess_address_data: Vec::new(),
+                       excess_data: Vec::new(),
+               };
+               let msghash = hash_to_message!(&Sha256dHash::hash(&announcement.encode()[..])[..]);
+
+               let mut channel_state = self.channel_state.lock().unwrap();
+               channel_state.pending_msg_events.push(events::MessageSendEvent::BroadcastNodeAnnouncement {
+                       msg: msgs::NodeAnnouncement {
+                               signature: self.secp_ctx.sign(&msghash, &self.our_network_key),
+                               contents: announcement
+                       },
+               });
+       }
+
        /// Processes HTLCs which are pending waiting on random forward delay.
        ///
        /// Should only really ever be called in response to a PendingHTLCsForwardable event.
@@ -2079,7 +2187,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        // If the update_add is completely bogus, the call will Err and we will close,
                                        // but if we've sent a shutdown and they haven't acknowledged it yet, we just
                                        // want to reject the new HTLC and fail it backwards instead of forwarding.
-                                       if let PendingHTLCStatus::Forward(PendingForwardHTLCInfo { incoming_shared_secret, .. }) = pending_forward_info {
+                                       if let PendingHTLCStatus::Forward(PendingHTLCInfo { incoming_shared_secret, .. }) = pending_forward_info {
                                                let chan_update = self.get_channel_update(chan.get());
                                                pending_forward_info = PendingHTLCStatus::Fail(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
                                                        channel_id: msg.channel_id,
@@ -2209,7 +2317,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
        }
 
        #[inline]
-       fn forward_htlcs(&self, per_source_pending_forwards: &mut [(u64, Vec<(PendingForwardHTLCInfo, u64)>)]) {
+       fn forward_htlcs(&self, per_source_pending_forwards: &mut [(u64, Vec<(PendingHTLCInfo, u64)>)]) {
                for &mut (prev_short_channel_id, ref mut pending_forwards) in per_source_pending_forwards {
                        let mut forward_event = None;
                        if !pending_forwards.is_empty() {
@@ -2467,7 +2575,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
        }
 }
 
-impl<ChanSigner: ChannelKeys> events::MessageSendEventsProvider for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref> events::MessageSendEventsProvider for ChannelManager<ChanSigner, M> where M::Target: ManyChannelMonitor {
        fn get_and_clear_pending_msg_events(&self) -> Vec<events::MessageSendEvent> {
                // TODO: Event release to users and serialization is currently race-y: it's very easy for a
                // user to serialize a ChannelManager with pending events in it and lose those events on
@@ -2492,7 +2600,7 @@ impl<ChanSigner: ChannelKeys> events::MessageSendEventsProvider for ChannelManag
        }
 }
 
-impl<ChanSigner: ChannelKeys> events::EventsProvider for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref> events::EventsProvider for ChannelManager<ChanSigner, M> where M::Target: ManyChannelMonitor {
        fn get_and_clear_pending_events(&self) -> Vec<events::Event> {
                // TODO: Event release to users and serialization is currently race-y: it's very easy for a
                // user to serialize a ChannelManager with pending events in it and lose those events on
@@ -2517,7 +2625,7 @@ impl<ChanSigner: ChannelKeys> events::EventsProvider for ChannelManager<ChanSign
        }
 }
 
-impl<ChanSigner: ChannelKeys> ChainListener for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send> ChainListener for ChannelManager<ChanSigner, M> where M::Target: ManyChannelMonitor {
        fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) {
                let header_hash = header.bitcoin_hash();
                log_trace!(self, "Block {} at height {} connected with {} txn matched", header_hash, height, txn_matched.len());
@@ -2631,7 +2739,7 @@ impl<ChanSigner: ChannelKeys> ChainListener for ChannelManager<ChanSigner> {
        }
 }
 
-impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send> ChannelMessageHandler for ChannelManager<ChanSigner, M> where M::Target: ManyChannelMonitor {
        fn handle_open_channel(&self, their_node_id: &PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel) {
                let _ = self.total_consistency_lock.read().unwrap();
                let res = self.internal_open_channel(their_node_id, their_features, msg);
@@ -2780,6 +2888,7 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                let _ = self.total_consistency_lock.read().unwrap();
                let mut failed_channels = Vec::new();
                let mut failed_payments = Vec::new();
+               let mut no_channels_remain = true;
                {
                        let mut channel_state_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_state_lock;
@@ -2818,6 +2927,8 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                                                                short_to_id.remove(&short_id);
                                                        }
                                                        return false;
+                                               } else {
+                                                       no_channels_remain = false;
                                                }
                                        }
                                        true
@@ -2837,12 +2948,17 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                                        &events::MessageSendEvent::SendShutdown { ref node_id, .. } => node_id != their_node_id,
                                        &events::MessageSendEvent::SendChannelReestablish { ref node_id, .. } => node_id != their_node_id,
                                        &events::MessageSendEvent::BroadcastChannelAnnouncement { .. } => true,
+                                       &events::MessageSendEvent::BroadcastNodeAnnouncement { .. } => true,
                                        &events::MessageSendEvent::BroadcastChannelUpdate { .. } => true,
                                        &events::MessageSendEvent::HandleError { ref node_id, .. } => node_id != their_node_id,
                                        &events::MessageSendEvent::PaymentFailureNetworkUpdate { .. } => true,
                                }
                        });
                }
+               if no_channels_remain {
+                       self.per_peer_state.write().unwrap().remove(their_node_id);
+               }
+
                for failure in failed_channels.drain(..) {
                        self.finish_force_close_channel(failure);
                }
@@ -2853,10 +2969,25 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                }
        }
 
-       fn peer_connected(&self, their_node_id: &PublicKey) {
+       fn peer_connected(&self, their_node_id: &PublicKey, init_msg: &msgs::Init) {
                log_debug!(self, "Generating channel_reestablish events for {}", log_pubkey!(their_node_id));
 
                let _ = self.total_consistency_lock.read().unwrap();
+
+               {
+                       let mut peer_state_lock = self.per_peer_state.write().unwrap();
+                       match peer_state_lock.entry(their_node_id.clone()) {
+                               hash_map::Entry::Vacant(e) => {
+                                       e.insert(Mutex::new(PeerState {
+                                               latest_features: init_msg.features.clone(),
+                                       }));
+                               },
+                               hash_map::Entry::Occupied(e) => {
+                                       e.get().lock().unwrap().latest_features = init_msg.features.clone();
+                               },
+                       }
+               }
+
                let mut channel_state_lock = self.channel_state.lock().unwrap();
                let channel_state = &mut *channel_state_lock;
                let pending_msg_events = &mut channel_state.pending_msg_events;
@@ -2898,7 +3029,7 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
 const SERIALIZATION_VERSION: u8 = 1;
 const MIN_SERIALIZATION_VERSION: u8 = 1;
 
-impl Writeable for PendingForwardHTLCInfo {
+impl Writeable for PendingHTLCInfo {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                self.onion_packet.write(writer)?;
                self.incoming_shared_secret.write(writer)?;
@@ -2910,9 +3041,9 @@ impl Writeable for PendingForwardHTLCInfo {
        }
 }
 
-impl<R: ::std::io::Read> Readable<R> for PendingForwardHTLCInfo {
-       fn read(reader: &mut R) -> Result<PendingForwardHTLCInfo, DecodeError> {
-               Ok(PendingForwardHTLCInfo {
+impl<R: ::std::io::Read> Readable<R> for PendingHTLCInfo {
+       fn read(reader: &mut R) -> Result<PendingHTLCInfo, DecodeError> {
+               Ok(PendingHTLCInfo {
                        onion_packet: Readable::read(reader)?,
                        incoming_shared_secret: Readable::read(reader)?,
                        payment_hash: Readable::read(reader)?,
@@ -3079,7 +3210,7 @@ impl<R: ::std::io::Read> Readable<R> for HTLCForwardInfo {
        }
 }
 
-impl<ChanSigner: ChannelKeys + Writeable> Writeable for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys + Writeable, M: Deref> Writeable for ChannelManager<ChanSigner, M> where M::Target: ManyChannelMonitor {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                let _ = self.total_consistency_lock.write().unwrap();
 
@@ -3123,6 +3254,16 @@ impl<ChanSigner: ChannelKeys + Writeable> Writeable for ChannelManager<ChanSigne
                        }
                }
 
+               let per_peer_state = self.per_peer_state.write().unwrap();
+               (per_peer_state.len() as u64).write(writer)?;
+               for (peer_pubkey, peer_state_mutex) in per_peer_state.iter() {
+                       peer_pubkey.write(writer)?;
+                       let peer_state = peer_state_mutex.lock().unwrap();
+                       peer_state.latest_features.write(writer)?;
+               }
+
+               (self.last_node_announcement_serial.load(Ordering::Acquire) as u32).write(writer)?;
+
                Ok(())
        }
 }
@@ -3142,7 +3283,7 @@ impl<ChanSigner: ChannelKeys + Writeable> Writeable for ChannelManager<ChanSigne
 /// 5) Move the ChannelMonitors into your local ManyChannelMonitor.
 /// 6) Disconnect/connect blocks on the ChannelManager.
 /// 7) Register the new ChannelManager with your ChainWatchInterface.
-pub struct ChannelManagerReadArgs<'a, ChanSigner: ChannelKeys> {
+pub struct ChannelManagerReadArgs<'a, ChanSigner: ChannelKeys, M: Deref> where M::Target: ManyChannelMonitor {
        /// The keys provider which will give us relevant keys. Some keys will be loaded during
        /// deserialization.
        pub keys_manager: Arc<KeysInterface<ChanKeySigner = ChanSigner>>,
@@ -3156,7 +3297,7 @@ pub struct ChannelManagerReadArgs<'a, ChanSigner: ChannelKeys> {
        /// No calls to the ManyChannelMonitor will be made during deserialization. It is assumed that
        /// you have deserialized ChannelMonitors separately and will add them to your
        /// ManyChannelMonitor after deserializing this ChannelManager.
-       pub monitor: Arc<ManyChannelMonitor>,
+       pub monitor: M,
 
        /// The BroadcasterInterface which will be used in the ChannelManager in the future and may be
        /// used to broadcast the latest local commitment transactions of channels which must be
@@ -3182,8 +3323,8 @@ pub struct ChannelManagerReadArgs<'a, ChanSigner: ChannelKeys> {
        pub channel_monitors: &'a mut HashMap<OutPoint, &'a mut ChannelMonitor>,
 }
 
-impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArgs<R, ChannelManagerReadArgs<'a, ChanSigner>> for (Sha256dHash, ChannelManager<ChanSigner>) {
-       fn read(reader: &mut R, args: ChannelManagerReadArgs<'a, ChanSigner>) -> Result<Self, DecodeError> {
+impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>, M: Deref> ReadableArgs<R, ChannelManagerReadArgs<'a, ChanSigner, M>> for (Sha256dHash, ChannelManager<ChanSigner, M>) where M::Target: ManyChannelMonitor {
+       fn read(reader: &mut R, args: ChannelManagerReadArgs<'a, ChanSigner, M>) -> Result<Self, DecodeError> {
                let _ver: u8 = Readable::read(reader)?;
                let min_ver: u8 = Readable::read(reader)?;
                if min_ver > SERIALIZATION_VERSION {
@@ -3256,6 +3397,18 @@ impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArg
                        claimable_htlcs.insert(payment_hash, previous_hops);
                }
 
+               let peer_count: u64 = Readable::read(reader)?;
+               let mut per_peer_state = HashMap::with_capacity(cmp::min(peer_count as usize, 128));
+               for _ in 0..peer_count {
+                       let peer_pubkey = Readable::read(reader)?;
+                       let peer_state = PeerState {
+                               latest_features: Readable::read(reader)?,
+                       };
+                       per_peer_state.insert(peer_pubkey, Mutex::new(peer_state));
+               }
+
+               let last_node_announcement_serial: u32 = Readable::read(reader)?;
+
                let channel_manager = ChannelManager {
                        genesis_hash,
                        fee_estimator: args.fee_estimator,
@@ -3275,6 +3428,10 @@ impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArg
                        }),
                        our_network_key: args.keys_manager.get_node_secret(),
 
+                       last_node_announcement_serial: AtomicUsize::new(last_node_announcement_serial as usize),
+
+                       per_peer_state: RwLock::new(per_peer_state),
+
                        pending_events: Mutex::new(Vec::new()),
                        total_consistency_lock: RwLock::new(()),
                        keys_manager: args.keys_manager,