Merge pull request #459 from ariard/2020-01-fix-htlc-height-timer
[rust-lightning] / lightning / src / ln / peer_handler.rs
index c0035f4f42c09692970b5d472af6df0d97a4193b..5838b782f4d4124a906d07f7d8e4c0cfad65eb8d 100644 (file)
@@ -8,27 +8,31 @@
 
 use secp256k1::key::{SecretKey,PublicKey};
 
+use ln::features::InitFeatures;
 use ln::msgs;
+use ln::msgs::ChannelMessageHandler;
+use ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager};
 use util::ser::{Writeable, Writer, Readable};
 use ln::peer_channel_encryptor::{PeerChannelEncryptor,NextNoiseStep};
 use util::byte_utils;
-use util::events::{MessageSendEvent};
+use util::events::{MessageSendEvent, MessageSendEventsProvider};
 use util::logger::Logger;
 
 use std::collections::{HashMap,hash_map,HashSet,LinkedList};
 use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::{cmp,error,hash,fmt};
+use std::ops::Deref;
 
 use bitcoin_hashes::sha256::Hash as Sha256;
 use bitcoin_hashes::sha256::HashEngine as Sha256Engine;
 use bitcoin_hashes::{HashEngine, Hash};
 
 /// Provides references to trait impls which handle different types of messages.
-pub struct MessageHandler {
+pub struct MessageHandler<CM: Deref> where CM::Target: msgs::ChannelMessageHandler {
        /// A message handler which handles messages specific to channels. Usually this is just a
        /// ChannelManager object.
-       pub chan_handler: Arc<msgs::ChannelMessageHandler>,
+       pub chan_handler: CM,
        /// A message handler which handles messages updating our knowledge of the network channel
        /// graph. Usually this is just a Router object.
        pub route_handler: Arc<msgs::RoutingMessageHandler>,
@@ -103,8 +107,7 @@ struct Peer {
        channel_encryptor: PeerChannelEncryptor,
        outbound: bool,
        their_node_id: Option<PublicKey>,
-       their_global_features: Option<msgs::GlobalFeatures>,
-       their_local_features: Option<msgs::LocalFeatures>,
+       their_features: Option<InitFeatures>,
 
        pending_outbound_buffer: LinkedList<Vec<u8>>,
        pending_outbound_buffer_first_msg_offset: usize,
@@ -115,6 +118,8 @@ struct Peer {
        pending_read_is_header: bool,
 
        sync_status: InitSyncTracker,
+
+       awaiting_pong: bool,
 }
 
 impl Peer {
@@ -141,20 +146,6 @@ struct PeerHolder<Descriptor: SocketDescriptor> {
        /// Only add to this set when noise completes:
        node_id_to_descriptor: HashMap<PublicKey, Descriptor>,
 }
-struct MutPeerHolder<'a, Descriptor: SocketDescriptor + 'a> {
-       peers: &'a mut HashMap<Descriptor, Peer>,
-       peers_needing_send: &'a mut HashSet<Descriptor>,
-       node_id_to_descriptor: &'a mut HashMap<PublicKey, Descriptor>,
-}
-impl<Descriptor: SocketDescriptor> PeerHolder<Descriptor> {
-       fn borrow_parts(&mut self) -> MutPeerHolder<Descriptor> {
-               MutPeerHolder {
-                       peers: &mut self.peers,
-                       peers_needing_send: &mut self.peers_needing_send,
-                       node_id_to_descriptor: &mut self.node_id_to_descriptor,
-               }
-       }
-}
 
 #[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
 fn _check_usize_is_32_or_64() {
@@ -162,10 +153,31 @@ fn _check_usize_is_32_or_64() {
        unsafe { mem::transmute::<*const usize, [u8; 4]>(panic!()); }
 }
 
+/// SimpleArcPeerManager is useful when you need a PeerManager 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
+/// SimpleRefPeerManager is the more appropriate type. Defining these type aliases prevents
+/// issues such as overly long function definitions.
+pub type SimpleArcPeerManager<SD, M> = Arc<PeerManager<SD, SimpleArcChannelManager<M>>>;
+
+/// SimpleRefPeerManager is a type alias for a PeerManager reference, and is the reference
+/// counterpart to the SimpleArcPeerManager type alias. Use this type by default when you don't
+/// need a PeerManager 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 SimpleRefPeerManager<'a, SD, M> = PeerManager<SD, SimpleRefChannelManager<'a, M>>;
+
 /// A PeerManager manages a set of peers, described by their SocketDescriptor and marshalls socket
 /// events into messages which it passes on to its MessageHandlers.
-pub struct PeerManager<Descriptor: SocketDescriptor> {
-       message_handler: MessageHandler,
+///
+/// Rather than using a plain PeerManager, it is preferable to use either a SimpleArcPeerManager
+/// a SimpleRefPeerManager, for conciseness. See their documentation for more details, but
+/// essentially you should default to using a SimpleRefPeerManager, and use a
+/// SimpleArcPeerManager when you require a PeerManager with a static lifetime, such as when
+/// you're using lightning-net-tokio.
+pub struct PeerManager<Descriptor: SocketDescriptor, CM: Deref> where CM::Target: msgs::ChannelMessageHandler {
+       message_handler: MessageHandler<CM>,
        peers: Mutex<PeerHolder<Descriptor>>,
        our_node_secret: SecretKey,
        ephemeral_key_midstate: Sha256Engine,
@@ -204,11 +216,11 @@ const INITIAL_SYNCS_TO_SEND: usize = 5;
 
 /// Manages and reacts to connection events. You probably want to use file descriptors as PeerIds.
 /// PeerIds may repeat, but only after disconnect_event() has been called.
-impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
+impl<Descriptor: SocketDescriptor, CM: Deref> PeerManager<Descriptor, CM> where CM::Target: msgs::ChannelMessageHandler {
        /// Constructs a new PeerManager with the given message handlers and node_id secret key
        /// ephemeral_random_data is used to derive per-connection ephemeral keys and must be
        /// cryptographically secure random bytes.
-       pub fn new(message_handler: MessageHandler, our_node_secret: SecretKey, ephemeral_random_data: &[u8; 32], logger: Arc<Logger>) -> PeerManager<Descriptor> {
+       pub fn new(message_handler: MessageHandler<CM>, our_node_secret: SecretKey, ephemeral_random_data: &[u8; 32], logger: Arc<Logger>) -> PeerManager<Descriptor, CM> {
                let mut ephemeral_key_midstate = Sha256::engine();
                ephemeral_key_midstate.input(ephemeral_random_data);
 
@@ -236,7 +248,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
        pub fn get_peer_node_ids(&self) -> Vec<PublicKey> {
                let peers = self.peers.lock().unwrap();
                peers.peers.values().filter_map(|p| {
-                       if !p.channel_encryptor.is_ready_for_encryption() || p.their_global_features.is_none() {
+                       if !p.channel_encryptor.is_ready_for_encryption() || p.their_features.is_none() {
                                return None;
                        }
                        p.their_node_id
@@ -274,8 +286,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                        channel_encryptor: peer_encryptor,
                        outbound: true,
                        their_node_id: None,
-                       their_global_features: None,
-                       their_local_features: None,
+                       their_features: None,
 
                        pending_outbound_buffer: LinkedList::new(),
                        pending_outbound_buffer_first_msg_offset: 0,
@@ -286,6 +297,8 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                        pending_read_is_header: false,
 
                        sync_status: InitSyncTracker::NoSyncRequested,
+
+                       awaiting_pong: false,
                }).is_some() {
                        panic!("PeerManager driver duplicated descriptors!");
                };
@@ -310,8 +323,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                        channel_encryptor: peer_encryptor,
                        outbound: false,
                        their_node_id: None,
-                       their_global_features: None,
-                       their_local_features: None,
+                       their_features: None,
 
                        pending_outbound_buffer: LinkedList::new(),
                        pending_outbound_buffer_first_msg_offset: 0,
@@ -322,6 +334,8 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                        pending_read_is_header: false,
 
                        sync_status: InitSyncTracker::NoSyncRequested,
+
+                       awaiting_pong: false,
                }).is_some() {
                        panic!("PeerManager driver duplicated descriptors!");
                };
@@ -447,7 +461,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
        fn do_read_event(&self, peer_descriptor: &mut Descriptor, data: Vec<u8>) -> Result<bool, PeerHandleError> {
                let pause_read = {
                        let mut peers_lock = self.peers.lock().unwrap();
-                       let peers = peers_lock.borrow_parts();
+                       let peers = &mut *peers_lock;
                        let pause_read = match peers.peers.get_mut(peer_descriptor) {
                                None => panic!("Descriptor for read_event is not already known to PeerManager"),
                                Some(peer) => {
@@ -564,14 +578,13 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
 
                                                                        peer.their_node_id = Some(their_node_id);
                                                                        insert_node_id!();
-                                                                       let mut local_features = msgs::LocalFeatures::new();
+                                                                       let mut features = InitFeatures::supported();
                                                                        if self.initial_syncs_sent.load(Ordering::Acquire) < INITIAL_SYNCS_TO_SEND {
                                                                                self.initial_syncs_sent.fetch_add(1, Ordering::AcqRel);
-                                                                               local_features.set_initial_routing_sync();
+                                                                               features.set_initial_routing_sync();
                                                                        }
                                                                        encode_and_send_msg!(msgs::Init {
-                                                                               global_features: msgs::GlobalFeatures::new(),
-                                                                               local_features,
+                                                                               features,
                                                                        }, 16);
                                                                },
                                                                NextNoiseStep::ActThree => {
@@ -600,7 +613,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
 
                                                                                let msg_type = byte_utils::slice_to_be16(&msg_data[0..2]);
                                                                                log_trace!(self, "Received message of type {} from {}", msg_type, log_pubkey!(peer.their_node_id.unwrap()));
-                                                                               if msg_type != 16 && peer.their_global_features.is_none() {
+                                                                               if msg_type != 16 && peer.their_features.is_none() {
                                                                                        // Need an init message as first message
                                                                                        log_trace!(self, "Peer {} sent non-Init first message", log_pubkey!(peer.their_node_id.unwrap()));
                                                                                        return Err(PeerHandleError{ no_connection_possible: false });
@@ -610,46 +623,44 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                                                                                        // Connection control:
                                                                                        16 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::Init::read(&mut reader));
-                                                                                               if msg.global_features.requires_unknown_bits() {
+                                                                                               if msg.features.requires_unknown_bits() {
                                                                                                        log_info!(self, "Peer global features required unknown version bits");
                                                                                                        return Err(PeerHandleError{ no_connection_possible: true });
                                                                                                }
-                                                                                               if msg.local_features.requires_unknown_bits() {
+                                                                                               if msg.features.requires_unknown_bits() {
                                                                                                        log_info!(self, "Peer local features required unknown version bits");
                                                                                                        return Err(PeerHandleError{ no_connection_possible: true });
                                                                                                }
-                                                                                               if peer.their_global_features.is_some() {
+                                                                                               if peer.their_features.is_some() {
                                                                                                        return Err(PeerHandleError{ no_connection_possible: false });
                                                                                                }
 
                                                                                                log_info!(self, "Received peer Init message: data_loss_protect: {}, initial_routing_sync: {}, upfront_shutdown_script: {}, unkown local flags: {}, unknown global flags: {}",
-                                                                                                       if msg.local_features.supports_data_loss_protect() { "supported" } else { "not supported"},
-                                                                                                       if msg.local_features.initial_routing_sync() { "requested" } else { "not requested" },
-                                                                                                       if msg.local_features.supports_upfront_shutdown_script() { "supported" } else { "not supported"},
-                                                                                                       if msg.local_features.supports_unknown_bits() { "present" } else { "none" },
-                                                                                                       if msg.global_features.supports_unknown_bits() { "present" } else { "none" });
+                                                                                                       if msg.features.supports_data_loss_protect() { "supported" } else { "not supported"},
+                                                                                                       if msg.features.initial_routing_sync() { "requested" } else { "not requested" },
+                                                                                                       if msg.features.supports_upfront_shutdown_script() { "supported" } else { "not supported"},
+                                                                                                       if msg.features.supports_unknown_bits() { "present" } else { "none" },
+                                                                                                       if msg.features.supports_unknown_bits() { "present" } else { "none" });
 
-                                                                                               if msg.local_features.initial_routing_sync() {
+                                                                                               if msg.features.initial_routing_sync() {
                                                                                                        peer.sync_status = InitSyncTracker::ChannelsSyncing(0);
                                                                                                        peers.peers_needing_send.insert(peer_descriptor.clone());
                                                                                                }
-                                                                                               peer.their_global_features = Some(msg.global_features);
-                                                                                               peer.their_local_features = Some(msg.local_features);
 
                                                                                                if !peer.outbound {
-                                                                                                       let mut local_features = msgs::LocalFeatures::new();
+                                                                                                       let mut features = InitFeatures::supported();
                                                                                                        if self.initial_syncs_sent.load(Ordering::Acquire) < INITIAL_SYNCS_TO_SEND {
                                                                                                                self.initial_syncs_sent.fetch_add(1, Ordering::AcqRel);
-                                                                                                               local_features.set_initial_routing_sync();
+                                                                                                               features.set_initial_routing_sync();
                                                                                                        }
 
                                                                                                        encode_and_send_msg!(msgs::Init {
-                                                                                                               global_features: msgs::GlobalFeatures::new(),
-                                                                                                               local_features,
+                                                                                                               features,
                                                                                                        }, 16);
                                                                                                }
 
-                                                                                               self.message_handler.chan_handler.peer_connected(&peer.their_node_id.unwrap());
+                                                                                               self.message_handler.chan_handler.peer_connected(&peer.their_node_id.unwrap(), &msg);
+                                                                                               peer.their_features = Some(msg.features);
                                                                                        },
                                                                                        17 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::ErrorMessage::read(&mut reader));
@@ -680,79 +691,79 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                                                                                                }
                                                                                        },
                                                                                        19 => {
+                                                                                               peer.awaiting_pong = false;
                                                                                                try_potential_decodeerror!(msgs::Pong::read(&mut reader));
                                                                                        },
-
                                                                                        // Channel control:
                                                                                        32 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::OpenChannel::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_open_channel(&peer.their_node_id.unwrap(), peer.their_local_features.clone().unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_open_channel(&peer.their_node_id.unwrap(), peer.their_features.clone().unwrap(), &msg);
                                                                                        },
                                                                                        33 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::AcceptChannel::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_accept_channel(&peer.their_node_id.unwrap(), peer.their_local_features.clone().unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_accept_channel(&peer.their_node_id.unwrap(), peer.their_features.clone().unwrap(), &msg);
                                                                                        },
 
                                                                                        34 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::FundingCreated::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_funding_created(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_funding_created(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        35 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::FundingSigned::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_funding_signed(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_funding_signed(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        36 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::FundingLocked::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_funding_locked(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_funding_locked(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
 
                                                                                        38 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::Shutdown::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_shutdown(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_shutdown(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        39 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::ClosingSigned::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_closing_signed(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_closing_signed(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
 
                                                                                        128 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::UpdateAddHTLC::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_update_add_htlc(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_update_add_htlc(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        130 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::UpdateFulfillHTLC::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_update_fulfill_htlc(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_update_fulfill_htlc(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        131 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::UpdateFailHTLC::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_update_fail_htlc(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_update_fail_htlc(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        135 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::UpdateFailMalformedHTLC::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_update_fail_malformed_htlc(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_update_fail_malformed_htlc(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
 
                                                                                        132 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::CommitmentSigned::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_commitment_signed(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_commitment_signed(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        133 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::RevokeAndACK::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_revoke_and_ack(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_revoke_and_ack(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        134 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::UpdateFee::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_update_fee(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_update_fee(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        136 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::ChannelReestablish::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_channel_reestablish(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_channel_reestablish(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
 
                                                                                        // Routing control:
                                                                                        259 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::AnnouncementSignatures::read(&mut reader));
-                                                                                               try_potential_handleerror!(self.message_handler.chan_handler.handle_announcement_signatures(&peer.their_node_id.unwrap(), &msg));
+                                                                                               self.message_handler.chan_handler.handle_announcement_signatures(&peer.their_node_id.unwrap(), &msg);
                                                                                        },
                                                                                        256 => {
                                                                                                let msg = try_potential_decodeerror!(msgs::ChannelAnnouncement::read(&mut reader));
@@ -813,7 +824,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
 
                        let mut events_generated = self.message_handler.chan_handler.get_and_clear_pending_msg_events();
                        let mut peers_lock = self.peers.lock().unwrap();
-                       let peers = peers_lock.borrow_parts();
+                       let peers = &mut *peers_lock;
                        for event in events_generated.drain(..) {
                                macro_rules! get_peer_for_forwarding {
                                        ($node_id: expr, $handle_no_such_peer: block) => {
@@ -827,7 +838,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                                                        };
                                                        match peers.peers.get_mut(&descriptor) {
                                                                Some(peer) => {
-                                                                       if peer.their_global_features.is_none() {
+                                                                       if peer.their_features.is_none() {
                                                                                $handle_no_such_peer;
                                                                                continue;
                                                                        }
@@ -978,7 +989,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                                                        let encoded_update_msg = encode_msg!(update_msg, 258);
 
                                                        for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
-                                                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_global_features.is_none() ||
+                                                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
                                                                                !peer.should_forward_channel(msg.contents.short_channel_id) {
                                                                        continue
                                                                }
@@ -1002,7 +1013,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                                                        let encoded_msg = encode_msg!(msg, 258);
 
                                                        for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
-                                                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_global_features.is_none() ||
+                                                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
                                                                                !peer.should_forward_channel(msg.contents.short_channel_id)  {
                                                                        continue
                                                                }
@@ -1088,6 +1099,48 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
                        }
                };
        }
+
+       /// This function should be called roughly once every 30 seconds.
+       /// It will send pings to each peer and disconnect those which did not respond to the last round of pings.
+
+       /// Will most likely call send_data on all of the registered descriptors, thus, be very careful with reentrancy issues!
+       pub fn timer_tick_occured(&self) {
+               let mut peers_lock = self.peers.lock().unwrap();
+               {
+                       let peers = &mut *peers_lock;
+                       let peers_needing_send = &mut peers.peers_needing_send;
+                       let node_id_to_descriptor = &mut peers.node_id_to_descriptor;
+                       let peers = &mut peers.peers;
+
+                       peers.retain(|descriptor, peer| {
+                               if peer.awaiting_pong == true {
+                                       peers_needing_send.remove(descriptor);
+                                       match peer.their_node_id {
+                                               Some(node_id) => {
+                                                       node_id_to_descriptor.remove(&node_id);
+                                                       self.message_handler.chan_handler.peer_disconnected(&node_id, true);
+                                               },
+                                               None => {}
+                                       }
+                               }
+
+                               let ping = msgs::Ping {
+                                       ponglen: 0,
+                                       byteslen: 64,
+                               };
+                               peer.pending_outbound_buffer.push_back(encode_msg!(ping, 18));
+                               let mut descriptor_clone = descriptor.clone();
+                               self.do_attempt_write_data(&mut descriptor_clone, peer);
+
+                               if peer.awaiting_pong {
+                                       false // Drop the peer
+                               } else {
+                                       peer.awaiting_pong = true;
+                                       true
+                               }
+                       });
+               }
+       }
 }
 
 #[cfg(test)]
@@ -1118,22 +1171,31 @@ mod tests {
                fn disconnect_socket(&mut self) {}
        }
 
-       fn create_network(peer_count: usize) -> Vec<PeerManager<FileDescriptor>> {
+       fn create_chan_handlers(peer_count: usize) -> Vec<test_utils::TestChannelMessageHandler> {
+               let mut chan_handlers = Vec::new();
+               for _ in 0..peer_count {
+                       let chan_handler = test_utils::TestChannelMessageHandler::new();
+                       chan_handlers.push(chan_handler);
+               }
+
+               chan_handlers
+       }
+
+       fn create_network<'a>(peer_count: usize, chan_handlers: &'a Vec<test_utils::TestChannelMessageHandler>) -> Vec<PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler>> {
                let mut peers = Vec::new();
                let mut rng = thread_rng();
                let logger : Arc<Logger> = Arc::new(test_utils::TestLogger::new());
                let mut ephemeral_bytes = [0; 32];
                rng.fill_bytes(&mut ephemeral_bytes);
 
-               for _ in 0..peer_count {
-                       let chan_handler = test_utils::TestChannelMessageHandler::new();
+               for i in 0..peer_count {
                        let router = test_utils::TestRoutingMessageHandler::new();
                        let node_id = {
                                let mut key_slice = [0;32];
                                rng.fill_bytes(&mut key_slice);
                                SecretKey::from_slice(&key_slice).unwrap()
                        };
-                       let msg_handler = MessageHandler { chan_handler: Arc::new(chan_handler), route_handler: Arc::new(router) };
+                       let msg_handler = MessageHandler { chan_handler: &chan_handlers[i], route_handler: Arc::new(router) };
                        let peer = PeerManager::new(msg_handler, node_id, &ephemeral_bytes, Arc::clone(&logger));
                        peers.push(peer);
                }
@@ -1141,7 +1203,7 @@ mod tests {
                peers
        }
 
-       fn establish_connection(peer_a: &PeerManager<FileDescriptor>, peer_b: &PeerManager<FileDescriptor>) {
+       fn establish_connection<'a>(peer_a: &PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler>, peer_b: &PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler>) {
                let secp_ctx = Secp256k1::new();
                let their_id = PublicKey::from_secret_key(&secp_ctx, &peer_b.our_node_secret);
                let fd = FileDescriptor { fd: 1};
@@ -1153,22 +1215,39 @@ mod tests {
        fn test_disconnect_peer() {
                // Simple test which builds a network of PeerManager, connects and brings them to NoiseState::Finished and
                // push a DisconnectPeer event to remove the node flagged by id
-               let mut peers = create_network(2);
+               let chan_handlers = create_chan_handlers(2);
+               let chan_handler = test_utils::TestChannelMessageHandler::new();
+               let mut peers = create_network(2, &chan_handlers);
                establish_connection(&peers[0], &peers[1]);
                assert_eq!(peers[0].peers.lock().unwrap().peers.len(), 1);
 
                let secp_ctx = Secp256k1::new();
                let their_id = PublicKey::from_secret_key(&secp_ctx, &peers[1].our_node_secret);
 
-               let chan_handler = test_utils::TestChannelMessageHandler::new();
                chan_handler.pending_events.lock().unwrap().push(events::MessageSendEvent::HandleError {
                        node_id: their_id,
                        action: msgs::ErrorAction::DisconnectPeer { msg: None },
                });
                assert_eq!(chan_handler.pending_events.lock().unwrap().len(), 1);
-               peers[0].message_handler.chan_handler = Arc::new(chan_handler);
+               peers[0].message_handler.chan_handler = &chan_handler;
 
                peers[0].process_events();
                assert_eq!(peers[0].peers.lock().unwrap().peers.len(), 0);
        }
+       #[test]
+       fn test_timer_tick_occured(){
+               // Create peers, a vector of two peer managers, perform initial set up and check that peers[0] has one Peer.
+               let chan_handlers = create_chan_handlers(2);
+               let peers = create_network(2, &chan_handlers);
+               establish_connection(&peers[0], &peers[1]);
+               assert_eq!(peers[0].peers.lock().unwrap().peers.len(), 1);
+
+               // peers[0] awaiting_pong is set to true, but the Peer is still connected
+               peers[0].timer_tick_occured();
+               assert_eq!(peers[0].peers.lock().unwrap().peers.len(), 1);
+
+               // Since timer_tick_occured() is called again when awaiting_pong is true, all Peers are disconnected
+               peers[0].timer_tick_occured();
+               assert_eq!(peers[0].peers.lock().unwrap().peers.len(), 0);
+       }
 }