[rust-lightning] / lightning / src / ln / peer_handler.rs

// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.

//! Top level peer message handling and socket handling logic lives here.
//!
//! Instead of actually servicing sockets ourselves we require that you implement the
//! SocketDescriptor interface and use that to receive actions which you should perform on the
//! socket, and call into PeerManager with bytes read from the socket. The PeerManager will then
//! call into the provided message handlers (probably a ChannelManager and P2PGossipSync) with
//! messages they should handle, and encoding/sending response messages.

use bitcoin::secp256k1::{self, Secp256k1, SecretKey, PublicKey};

use ln::features::{InitFeatures, NodeFeatures};
use ln::msgs;
use ln::msgs::{ChannelMessageHandler, LightningError, NetAddress, OnionMessageHandler, RoutingMessageHandler};
use ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager};
use util::ser::{VecWriter, Writeable, Writer};
use ln::peer_channel_encryptor::{PeerChannelEncryptor,NextNoiseStep};
use ln::wire;
use ln::wire::Encode;
use onion_message::{SimpleArcOnionMessenger, SimpleRefOnionMessenger};
use routing::gossip::{NetworkGraph, P2PGossipSync};
use util::atomic_counter::AtomicCounter;
use util::crypto::sign;
use util::events::{MessageSendEvent, MessageSendEventsProvider, OnionMessageProvider};
use util::logger::Logger;

use prelude::*;
use io;
use alloc::collections::LinkedList;
use sync::{Arc, Mutex, MutexGuard, FairRwLock};
use core::sync::atomic::{AtomicBool, AtomicU64, Ordering};
use core::{cmp, hash, fmt, mem};
use core::ops::Deref;
use core::convert::Infallible;
#[cfg(feature = "std")] use std::error;

use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hashes::sha256d::Hash as Sha256dHash;
use bitcoin::hashes::sha256::HashEngine as Sha256Engine;
use bitcoin::hashes::{HashEngine, Hash};

/// Handler for BOLT1-compliant messages.
pub trait CustomMessageHandler: wire::CustomMessageReader {
        /// Called with the message type that was received and the buffer to be read.
        /// Can return a `MessageHandlingError` if the message could not be handled.
        fn handle_custom_message(&self, msg: Self::CustomMessage, sender_node_id: &PublicKey) -> Result<(), LightningError>;

        /// Gets the list of pending messages which were generated by the custom message
        /// handler, clearing the list in the process. The first tuple element must
        /// correspond to the intended recipients node ids. If no connection to one of the
        /// specified node does not exist, the message is simply not sent to it.
        fn get_and_clear_pending_msg(&self) -> Vec<(PublicKey, Self::CustomMessage)>;
}

/// A dummy struct which implements `RoutingMessageHandler` without storing any routing information
/// or doing any processing. You can provide one of these as the route_handler in a MessageHandler.
pub struct IgnoringMessageHandler{}
impl MessageSendEventsProvider for IgnoringMessageHandler {
        fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent> { Vec::new() }
}
impl RoutingMessageHandler for IgnoringMessageHandler {
        fn handle_node_announcement(&self, _msg: &msgs::NodeAnnouncement) -> Result<bool, LightningError> { Ok(false) }
        fn handle_channel_announcement(&self, _msg: &msgs::ChannelAnnouncement) -> Result<bool, LightningError> { Ok(false) }
        fn handle_channel_update(&self, _msg: &msgs::ChannelUpdate) -> Result<bool, LightningError> { Ok(false) }
        fn get_next_channel_announcement(&self, _starting_point: u64) ->
                Option<(msgs::ChannelAnnouncement, Option<msgs::ChannelUpdate>, Option<msgs::ChannelUpdate>)> { None }
        fn get_next_node_announcement(&self, _starting_point: Option<&PublicKey>) -> Option<msgs::NodeAnnouncement> { None }
        fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init) {}
        fn handle_reply_channel_range(&self, _their_node_id: &PublicKey, _msg: msgs::ReplyChannelRange) -> Result<(), LightningError> { Ok(()) }
        fn handle_reply_short_channel_ids_end(&self, _their_node_id: &PublicKey, _msg: msgs::ReplyShortChannelIdsEnd) -> Result<(), LightningError> { Ok(()) }
        fn handle_query_channel_range(&self, _their_node_id: &PublicKey, _msg: msgs::QueryChannelRange) -> Result<(), LightningError> { Ok(()) }
        fn handle_query_short_channel_ids(&self, _their_node_id: &PublicKey, _msg: msgs::QueryShortChannelIds) -> Result<(), LightningError> { Ok(()) }
        fn provided_node_features(&self) -> NodeFeatures { NodeFeatures::empty() }
        fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
                InitFeatures::empty()
        }
}
impl OnionMessageProvider for IgnoringMessageHandler {
        fn next_onion_message_for_peer(&self, _peer_node_id: PublicKey) -> Option<msgs::OnionMessage> { None }
}
impl OnionMessageHandler for IgnoringMessageHandler {
        fn handle_onion_message(&self, _their_node_id: &PublicKey, _msg: &msgs::OnionMessage) {}
        fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init) {}
        fn peer_disconnected(&self, _their_node_id: &PublicKey, _no_connection_possible: bool) {}
        fn provided_node_features(&self) -> NodeFeatures { NodeFeatures::empty() }
        fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
                InitFeatures::empty()
        }
}
impl Deref for IgnoringMessageHandler {
        type Target = IgnoringMessageHandler;
        fn deref(&self) -> &Self { self }
}

// Implement Type for Infallible, note that it cannot be constructed, and thus you can never call a
// method that takes self for it.
impl wire::Type for Infallible {
        fn type_id(&self) -> u16 {
                unreachable!();
        }
}
impl Writeable for Infallible {
        fn write<W: Writer>(&self, _: &mut W) -> Result<(), io::Error> {
                unreachable!();
        }
}

impl wire::CustomMessageReader for IgnoringMessageHandler {
        type CustomMessage = Infallible;
        fn read<R: io::Read>(&self, _message_type: u16, _buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError> {
                Ok(None)
        }
}

impl CustomMessageHandler for IgnoringMessageHandler {
        fn handle_custom_message(&self, _msg: Infallible, _sender_node_id: &PublicKey) -> Result<(), LightningError> {
                // Since we always return `None` in the read the handle method should never be called.
                unreachable!();
        }

        fn get_and_clear_pending_msg(&self) -> Vec<(PublicKey, Self::CustomMessage)> { Vec::new() }
}

/// A dummy struct which implements `ChannelMessageHandler` without having any channels.
/// You can provide one of these as the route_handler in a MessageHandler.
pub struct ErroringMessageHandler {
        message_queue: Mutex<Vec<MessageSendEvent>>
}
impl ErroringMessageHandler {
        /// Constructs a new ErroringMessageHandler
        pub fn new() -> Self {
                Self { message_queue: Mutex::new(Vec::new()) }
        }
        fn push_error(&self, node_id: &PublicKey, channel_id: [u8; 32]) {
                self.message_queue.lock().unwrap().push(MessageSendEvent::HandleError {
                        action: msgs::ErrorAction::SendErrorMessage {
                                msg: msgs::ErrorMessage { channel_id, data: "We do not support channel messages, sorry.".to_owned() },
                        },
                        node_id: node_id.clone(),
                });
        }
}
impl MessageSendEventsProvider for ErroringMessageHandler {
        fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent> {
                let mut res = Vec::new();
                mem::swap(&mut res, &mut self.message_queue.lock().unwrap());
                res
        }
}
impl ChannelMessageHandler for ErroringMessageHandler {
        // Any messages which are related to a specific channel generate an error message to let the
        // peer know we don't care about channels.
        fn handle_open_channel(&self, their_node_id: &PublicKey, _their_features: InitFeatures, msg: &msgs::OpenChannel) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.temporary_channel_id);
        }
        fn handle_accept_channel(&self, their_node_id: &PublicKey, _their_features: InitFeatures, msg: &msgs::AcceptChannel) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.temporary_channel_id);
        }
        fn handle_funding_created(&self, their_node_id: &PublicKey, msg: &msgs::FundingCreated) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.temporary_channel_id);
        }
        fn handle_funding_signed(&self, their_node_id: &PublicKey, msg: &msgs::FundingSigned) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_channel_ready(&self, their_node_id: &PublicKey, msg: &msgs::ChannelReady) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_shutdown(&self, their_node_id: &PublicKey, _their_features: &InitFeatures, msg: &msgs::Shutdown) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_closing_signed(&self, their_node_id: &PublicKey, msg: &msgs::ClosingSigned) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_update_add_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateAddHTLC) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_update_fulfill_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFulfillHTLC) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_update_fail_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFailHTLC) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_update_fail_malformed_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFailMalformedHTLC) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_commitment_signed(&self, their_node_id: &PublicKey, msg: &msgs::CommitmentSigned) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_revoke_and_ack(&self, their_node_id: &PublicKey, msg: &msgs::RevokeAndACK) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_update_fee(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFee) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_announcement_signatures(&self, their_node_id: &PublicKey, msg: &msgs::AnnouncementSignatures) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        fn handle_channel_reestablish(&self, their_node_id: &PublicKey, msg: &msgs::ChannelReestablish) {
                ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
        }
        // msgs::ChannelUpdate does not contain the channel_id field, so we just drop them.
        fn handle_channel_update(&self, _their_node_id: &PublicKey, _msg: &msgs::ChannelUpdate) {}
        fn peer_disconnected(&self, _their_node_id: &PublicKey, _no_connection_possible: bool) {}
        fn peer_connected(&self, _their_node_id: &PublicKey, _msg: &msgs::Init) {}
        fn handle_error(&self, _their_node_id: &PublicKey, _msg: &msgs::ErrorMessage) {}
        fn provided_node_features(&self) -> NodeFeatures { NodeFeatures::empty() }
        fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
                // Use our known channel feature set as peers may otherwise not be willing to talk to us at
                // all.
                InitFeatures::known_channel_features()
        }
}
impl Deref for ErroringMessageHandler {
        type Target = ErroringMessageHandler;
        fn deref(&self) -> &Self { self }
}

/// Provides references to trait impls which handle different types of messages.
pub struct MessageHandler<CM: Deref, RM: Deref, OM: Deref> where
                CM::Target: ChannelMessageHandler,
                RM::Target: RoutingMessageHandler,
                OM::Target: OnionMessageHandler,
{
        /// A message handler which handles messages specific to channels. Usually this is just a
        /// [`ChannelManager`] object or an [`ErroringMessageHandler`].
        ///
        /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
        pub chan_handler: CM,
        /// A message handler which handles messages updating our knowledge of the network channel
        /// graph. Usually this is just a [`P2PGossipSync`] object or an [`IgnoringMessageHandler`].
        ///
        /// [`P2PGossipSync`]: crate::routing::gossip::P2PGossipSync
        pub route_handler: RM,

        /// A message handler which handles onion messages. For now, this can only be an
        /// [`IgnoringMessageHandler`].
        pub onion_message_handler: OM,
}

/// Provides an object which can be used to send data to and which uniquely identifies a connection
/// to a remote host. You will need to be able to generate multiple of these which meet Eq and
/// implement Hash to meet the PeerManager API.
///
/// For efficiency, Clone should be relatively cheap for this type.
///
/// Two descriptors may compare equal (by [`cmp::Eq`] and [`hash::Hash`]) as long as the original
/// has been disconnected, the [`PeerManager`] has been informed of the disconnection (either by it
/// having triggered the disconnection or a call to [`PeerManager::socket_disconnected`]), and no
/// further calls to the [`PeerManager`] related to the original socket occur. This allows you to
/// use a file descriptor for your SocketDescriptor directly, however for simplicity you may wish
/// to simply use another value which is guaranteed to be globally unique instead.
pub trait SocketDescriptor : cmp::Eq + hash::Hash + Clone {
        /// Attempts to send some data from the given slice to the peer.
        ///
        /// Returns the amount of data which was sent, possibly 0 if the socket has since disconnected.
        /// Note that in the disconnected case, [`PeerManager::socket_disconnected`] must still be
        /// called and further write attempts may occur until that time.
        ///
        /// If the returned size is smaller than `data.len()`, a
        /// [`PeerManager::write_buffer_space_avail`] call must be made the next time more data can be
        /// written. Additionally, until a `send_data` event completes fully, no further
        /// [`PeerManager::read_event`] calls should be made for the same peer! Because this is to
        /// prevent denial-of-service issues, you should not read or buffer any data from the socket
        /// until then.
        ///
        /// If a [`PeerManager::read_event`] call on this descriptor had previously returned true
        /// (indicating that read events should be paused to prevent DoS in the send buffer),
        /// `resume_read` may be set indicating that read events on this descriptor should resume. A
        /// `resume_read` of false carries no meaning, and should not cause any action.
        fn send_data(&mut self, data: &[u8], resume_read: bool) -> usize;
        /// Disconnect the socket pointed to by this SocketDescriptor.
        ///
        /// You do *not* need to call [`PeerManager::socket_disconnected`] with this socket after this
        /// call (doing so is a noop).
        fn disconnect_socket(&mut self);
}

/// Error for PeerManager errors. If you get one of these, you must disconnect the socket and
/// generate no further read_event/write_buffer_space_avail/socket_disconnected calls for the
/// descriptor.
#[derive(Clone)]
pub struct PeerHandleError {
        /// Used to indicate that we probably can't make any future connections to this peer (e.g.
        /// because we required features that our peer was missing, or vice versa).
        ///
        /// While LDK's [`ChannelManager`] will not do it automatically, you likely wish to force-close
        /// any channels with this peer or check for new versions of LDK.
        ///
        /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
        pub no_connection_possible: bool,
}
impl fmt::Debug for PeerHandleError {
        fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                formatter.write_str("Peer Sent Invalid Data")
        }
}
impl fmt::Display for PeerHandleError {
        fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                formatter.write_str("Peer Sent Invalid Data")
        }
}

#[cfg(feature = "std")]
impl error::Error for PeerHandleError {
        fn description(&self) -> &str {
                "Peer Sent Invalid Data"
        }
}

enum InitSyncTracker{
        NoSyncRequested,
        ChannelsSyncing(u64),
        NodesSyncing(PublicKey),
}

/// The ratio between buffer sizes at which we stop sending initial sync messages vs when we stop
/// forwarding gossip messages to peers altogether.
const FORWARD_INIT_SYNC_BUFFER_LIMIT_RATIO: usize = 2;

/// When the outbound buffer has this many messages, we'll stop reading bytes from the peer until
/// we have fewer than this many messages in the outbound buffer again.
/// We also use this as the target number of outbound gossip messages to keep in the write buffer,
/// refilled as we send bytes.
const OUTBOUND_BUFFER_LIMIT_READ_PAUSE: usize = 12;
/// When the outbound buffer has this many messages, we'll simply skip relaying gossip messages to
/// the peer.
const OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP: usize = OUTBOUND_BUFFER_LIMIT_READ_PAUSE * FORWARD_INIT_SYNC_BUFFER_LIMIT_RATIO;

/// If we've sent a ping, and are still awaiting a response, we may need to churn our way through
/// the socket receive buffer before receiving the ping.
///
/// On a fairly old Arm64 board, with Linux defaults, this can take as long as 20 seconds, not
/// including any network delays, outbound traffic, or the same for messages from other peers.
///
/// Thus, to avoid needlessly disconnecting a peer, we allow a peer to take this many timer ticks
/// per connected peer to respond to a ping, as long as they send us at least one message during
/// each tick, ensuring we aren't actually just disconnected.
/// With a timer tick interval of ten seconds, this translates to about 40 seconds per connected
/// peer.
///
/// When we improve parallelism somewhat we should reduce this to e.g. this many timer ticks per
/// two connected peers, assuming most LDK-running systems have at least two cores.
const MAX_BUFFER_DRAIN_TICK_INTERVALS_PER_PEER: i8 = 4;

/// This is the minimum number of messages we expect a peer to be able to handle within one timer
/// tick. Once we have sent this many messages since the last ping, we send a ping right away to
/// ensures we don't just fill up our send buffer and leave the peer with too many messages to
/// process before the next ping.
///
/// Note that we continue responding to other messages even after we've sent this many messages, so
/// it's more of a general guideline used for gossip backfill (and gossip forwarding, times
/// [`FORWARD_INIT_SYNC_BUFFER_LIMIT_RATIO`]) than a hard limit.
const BUFFER_DRAIN_MSGS_PER_TICK: usize = 32;

struct Peer {
        channel_encryptor: PeerChannelEncryptor,
        their_node_id: Option<PublicKey>,
        their_features: Option<InitFeatures>,
        their_net_address: Option<NetAddress>,

        pending_outbound_buffer: LinkedList<Vec<u8>>,
        pending_outbound_buffer_first_msg_offset: usize,
        // Queue gossip broadcasts separately from `pending_outbound_buffer` so we can easily prioritize
        // channel messages over them.
        gossip_broadcast_buffer: LinkedList<Vec<u8>>,
        awaiting_write_event: bool,

        pending_read_buffer: Vec<u8>,
        pending_read_buffer_pos: usize,
        pending_read_is_header: bool,

        sync_status: InitSyncTracker,

        msgs_sent_since_pong: usize,
        awaiting_pong_timer_tick_intervals: i8,
        received_message_since_timer_tick: bool,
        sent_gossip_timestamp_filter: bool,
}

impl Peer {
        /// Returns true if the channel announcements/updates for the given channel should be
        /// forwarded to this peer.
        /// If we are sending our routing table to this peer and we have not yet sent channel
        /// announcements/updates for the given channel_id then we will send it when we get to that
        /// point and we shouldn't send it yet to avoid sending duplicate updates. If we've already
        /// sent the old versions, we should send the update, and so return true here.
        fn should_forward_channel_announcement(&self, channel_id: u64) -> bool {
                if self.their_features.as_ref().unwrap().supports_gossip_queries() &&
                        !self.sent_gossip_timestamp_filter {
                                return false;
                        }
                match self.sync_status {
                        InitSyncTracker::NoSyncRequested => true,
                        InitSyncTracker::ChannelsSyncing(i) => i < channel_id,
                        InitSyncTracker::NodesSyncing(_) => true,
                }
        }

        /// Similar to the above, but for node announcements indexed by node_id.
        fn should_forward_node_announcement(&self, node_id: PublicKey) -> bool {
                if self.their_features.as_ref().unwrap().supports_gossip_queries() &&
                        !self.sent_gossip_timestamp_filter {
                                return false;
                        }
                match self.sync_status {
                        InitSyncTracker::NoSyncRequested => true,
                        InitSyncTracker::ChannelsSyncing(_) => false,
                        InitSyncTracker::NodesSyncing(pk) => pk < node_id,
                }
        }

        /// Returns whether we should be reading bytes from this peer, based on whether its outbound
        /// buffer still has space and we don't need to pause reads to get some writes out.
        fn should_read(&self) -> bool {
                self.pending_outbound_buffer.len() < OUTBOUND_BUFFER_LIMIT_READ_PAUSE
        }

        /// Determines if we should push additional gossip background sync (aka "backfill") onto a peer's
        /// outbound buffer. This is checked every time the peer's buffer may have been drained.
        fn should_buffer_gossip_backfill(&self) -> bool {
                self.pending_outbound_buffer.is_empty() && self.gossip_broadcast_buffer.is_empty()
                        && self.msgs_sent_since_pong < BUFFER_DRAIN_MSGS_PER_TICK
        }

        /// Determines if we should push an onion message onto a peer's outbound buffer. This is checked
        /// every time the peer's buffer may have been drained.
        fn should_buffer_onion_message(&self) -> bool {
                self.pending_outbound_buffer.is_empty()
                        && self.msgs_sent_since_pong < BUFFER_DRAIN_MSGS_PER_TICK
        }

        /// Determines if we should push additional gossip broadcast messages onto a peer's outbound
        /// buffer. This is checked every time the peer's buffer may have been drained.
        fn should_buffer_gossip_broadcast(&self) -> bool {
                self.pending_outbound_buffer.is_empty()
                        && self.msgs_sent_since_pong < BUFFER_DRAIN_MSGS_PER_TICK
        }

        /// Returns whether this peer's outbound buffers are full and we should drop gossip broadcasts.
        fn buffer_full_drop_gossip_broadcast(&self) -> bool {
                let total_outbound_buffered =
                        self.gossip_broadcast_buffer.len() + self.pending_outbound_buffer.len();

                total_outbound_buffered > OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP ||
                        self.msgs_sent_since_pong > BUFFER_DRAIN_MSGS_PER_TICK * FORWARD_INIT_SYNC_BUFFER_LIMIT_RATIO
        }
}

/// 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.
///
/// (C-not exported) as `Arc`s don't make sense in bindings.
pub type SimpleArcPeerManager<SD, M, T, F, C, L> = PeerManager<SD, Arc<SimpleArcChannelManager<M, T, F, L>>, Arc<P2PGossipSync<Arc<NetworkGraph<Arc<L>>>, Arc<C>, Arc<L>>>, Arc<SimpleArcOnionMessenger<L>>, Arc<L>, IgnoringMessageHandler>;

/// 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.
///
/// (C-not exported) as general type aliases don't make sense in bindings.
pub type SimpleRefPeerManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, 'k, SD, M, T, F, C, L> = PeerManager<SD, SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, M, T, F, L>, &'e P2PGossipSync<&'g NetworkGraph<&'f L>, &'h C, &'f L>, &'i SimpleRefOnionMessenger<'j, 'k, L>, &'f L, IgnoringMessageHandler>;

/// A PeerManager manages a set of peers, described by their [`SocketDescriptor`] and marshalls
/// socket events into messages which it passes on to its [`MessageHandler`].
///
/// Locks are taken internally, so you must never assume that reentrancy from a
/// [`SocketDescriptor`] call back into [`PeerManager`] methods will not deadlock.
///
/// Calls to [`read_event`] will decode relevant messages and pass them to the
/// [`ChannelMessageHandler`], likely doing message processing in-line. Thus, the primary form of
/// parallelism in Rust-Lightning is in calls to [`read_event`]. Note, however, that calls to any
/// [`PeerManager`] functions related to the same connection must occur only in serial, making new
/// calls only after previous ones have returned.
///
/// 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.
///
/// [`read_event`]: PeerManager::read_event
pub struct PeerManager<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CMH: Deref> where
                CM::Target: ChannelMessageHandler,
                RM::Target: RoutingMessageHandler,
                OM::Target: OnionMessageHandler,
                L::Target: Logger,
                CMH::Target: CustomMessageHandler {
        message_handler: MessageHandler<CM, RM, OM>,
        /// Connection state for each connected peer - we have an outer read-write lock which is taken
        /// as read while we're doing processing for a peer and taken write when a peer is being added
        /// or removed.
        ///
        /// The inner Peer lock is held for sending and receiving bytes, but note that we do *not* hold
        /// it while we're processing a message. This is fine as [`PeerManager::read_event`] requires
        /// that there be no parallel calls for a given peer, so mutual exclusion of messages handed to
        /// the `MessageHandler`s for a given peer is already guaranteed.
        peers: FairRwLock<HashMap<Descriptor, Mutex<Peer>>>,
        /// Only add to this set when noise completes.
        /// Locked *after* peers. When an item is removed, it must be removed with the `peers` write
        /// lock held. Entries may be added with only the `peers` read lock held (though the
        /// `Descriptor` value must already exist in `peers`).
        node_id_to_descriptor: Mutex<HashMap<PublicKey, Descriptor>>,
        /// We can only have one thread processing events at once, but we don't usually need the full
        /// `peers` write lock to do so, so instead we block on this empty mutex when entering
        /// `process_events`.
        event_processing_lock: Mutex<()>,
        /// Because event processing is global and always does all available work before returning,
        /// there is no reason for us to have many event processors waiting on the lock at once.
        /// Instead, we limit the total blocked event processors to always exactly one by setting this
        /// when an event process call is waiting.
        blocked_event_processors: AtomicBool,

        /// Used to track the last value sent in a node_announcement "timestamp" field. We ensure this
        /// value increases strictly since we don't assume access to a time source.
        last_node_announcement_serial: AtomicU64,

        our_node_secret: SecretKey,
        ephemeral_key_midstate: Sha256Engine,
        custom_message_handler: CMH,

        peer_counter: AtomicCounter,

        logger: L,
        secp_ctx: Secp256k1<secp256k1::SignOnly>
}

enum MessageHandlingError {
        PeerHandleError(PeerHandleError),
        LightningError(LightningError),
}

impl From<PeerHandleError> for MessageHandlingError {
        fn from(error: PeerHandleError) -> Self {
                MessageHandlingError::PeerHandleError(error)
        }
}

impl From<LightningError> for MessageHandlingError {
        fn from(error: LightningError) -> Self {
                MessageHandlingError::LightningError(error)
        }
}

macro_rules! encode_msg {
        ($msg: expr) => {{
                let mut buffer = VecWriter(Vec::new());
                wire::write($msg, &mut buffer).unwrap();
                buffer.0
        }}
}

impl<Descriptor: SocketDescriptor, CM: Deref, OM: Deref, L: Deref> PeerManager<Descriptor, CM, IgnoringMessageHandler, OM, L, IgnoringMessageHandler> where
                CM::Target: ChannelMessageHandler,
                OM::Target: OnionMessageHandler,
                L::Target: Logger {
        /// Constructs a new `PeerManager` with the given `ChannelMessageHandler` and
        /// `OnionMessageHandler`. No routing message handler is used and network graph messages are
        /// ignored.
        ///
        /// ephemeral_random_data is used to derive per-connection ephemeral keys and must be
        /// cryptographically secure random bytes.
        ///
        /// `current_time` is used as an always-increasing counter that survives across restarts and is
        /// incremented irregularly internally. In general it is best to simply use the current UNIX
        /// timestamp, however if it is not available a persistent counter that increases once per
        /// minute should suffice.
        ///
        /// (C-not exported) as we can't export a PeerManager with a dummy route handler
        pub fn new_channel_only(channel_message_handler: CM, onion_message_handler: OM, our_node_secret: SecretKey, current_time: u64, ephemeral_random_data: &[u8; 32], logger: L) -> Self {
                Self::new(MessageHandler {
                        chan_handler: channel_message_handler,
                        route_handler: IgnoringMessageHandler{},
                        onion_message_handler,
                }, our_node_secret, current_time, ephemeral_random_data, logger, IgnoringMessageHandler{})
        }
}

impl<Descriptor: SocketDescriptor, RM: Deref, L: Deref> PeerManager<Descriptor, ErroringMessageHandler, RM, IgnoringMessageHandler, L, IgnoringMessageHandler> where
                RM::Target: RoutingMessageHandler,
                L::Target: Logger {
        /// Constructs a new `PeerManager` with the given `RoutingMessageHandler`. No channel message
        /// handler or onion message handler is used and onion and channel messages will be ignored (or
        /// generate error messages). Note that some other lightning implementations time-out connections
        /// after some time if no channel is built with the peer.
        ///
        /// `current_time` is used as an always-increasing counter that survives across restarts and is
        /// incremented irregularly internally. In general it is best to simply use the current UNIX
        /// timestamp, however if it is not available a persistent counter that increases once per
        /// minute should suffice.
        ///
        /// ephemeral_random_data is used to derive per-connection ephemeral keys and must be
        /// cryptographically secure random bytes.
        ///
        /// (C-not exported) as we can't export a PeerManager with a dummy channel handler
        pub fn new_routing_only(routing_message_handler: RM, our_node_secret: SecretKey, current_time: u64, ephemeral_random_data: &[u8; 32], logger: L) -> Self {
                Self::new(MessageHandler {
                        chan_handler: ErroringMessageHandler::new(),
                        route_handler: routing_message_handler,
                        onion_message_handler: IgnoringMessageHandler{},
                }, our_node_secret, current_time, ephemeral_random_data, logger, IgnoringMessageHandler{})
        }
}

/// A simple wrapper that optionally prints " from <pubkey>" for an optional pubkey.
/// This works around `format!()` taking a reference to each argument, preventing
/// `if let Some(node_id) = peer.their_node_id { format!(.., node_id) } else { .. }` from compiling
/// due to lifetime errors.
struct OptionalFromDebugger<'a>(&'a Option<PublicKey>);
impl core::fmt::Display for OptionalFromDebugger<'_> {
        fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> Result<(), core::fmt::Error> {
                if let Some(node_id) = self.0 { write!(f, " from {}", log_pubkey!(node_id)) } else { Ok(()) }
        }
}

/// A function used to filter out local or private addresses
/// https://www.iana.org./assignments/ipv4-address-space/ipv4-address-space.xhtml
/// https://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml
fn filter_addresses(ip_address: Option<NetAddress>) -> Option<NetAddress> {
        match ip_address{
                // For IPv4 range 10.0.0.0 - 10.255.255.255 (10/8)
                Some(NetAddress::IPv4{addr: [10, _, _, _], port: _}) => None,
                // For IPv4 range 0.0.0.0 - 0.255.255.255 (0/8)
                Some(NetAddress::IPv4{addr: [0, _, _, _], port: _}) => None,
                // For IPv4 range 100.64.0.0 - 100.127.255.255 (100.64/10)
                Some(NetAddress::IPv4{addr: [100, 64..=127, _, _], port: _}) => None,
                // For IPv4 range       127.0.0.0 - 127.255.255.255 (127/8)
                Some(NetAddress::IPv4{addr: [127, _, _, _], port: _}) => None,
                // For IPv4 range       169.254.0.0 - 169.254.255.255 (169.254/16)
                Some(NetAddress::IPv4{addr: [169, 254, _, _], port: _}) => None,
                // For IPv4 range 172.16.0.0 - 172.31.255.255 (172.16/12)
                Some(NetAddress::IPv4{addr: [172, 16..=31, _, _], port: _}) => None,
                // For IPv4 range 192.168.0.0 - 192.168.255.255 (192.168/16)
                Some(NetAddress::IPv4{addr: [192, 168, _, _], port: _}) => None,
                // For IPv4 range 192.88.99.0 - 192.88.99.255  (192.88.99/24)
                Some(NetAddress::IPv4{addr: [192, 88, 99, _], port: _}) => None,
                // For IPv6 range 2000:0000:0000:0000:0000:0000:0000:0000 - 3fff:ffff:ffff:ffff:ffff:ffff:ffff:ffff (2000::/3)
                Some(NetAddress::IPv6{addr: [0x20..=0x3F, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _], port: _}) => ip_address,
                // For remaining addresses
                Some(NetAddress::IPv6{addr: _, port: _}) => None,
                Some(..) => ip_address,
                None => None,
        }
}

impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CMH: Deref> PeerManager<Descriptor, CM, RM, OM, L, CMH> where
                CM::Target: ChannelMessageHandler,
                RM::Target: RoutingMessageHandler,
                OM::Target: OnionMessageHandler,
                L::Target: Logger,
                CMH::Target: CustomMessageHandler {
        /// 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.
        ///
        /// `current_time` is used as an always-increasing counter that survives across restarts and is
        /// incremented irregularly internally. In general it is best to simply use the current UNIX
        /// timestamp, however if it is not available a persistent counter that increases once per
        /// minute should suffice.
        pub fn new(message_handler: MessageHandler<CM, RM, OM>, our_node_secret: SecretKey, current_time: u64, ephemeral_random_data: &[u8; 32], logger: L, custom_message_handler: CMH) -> Self {
                let mut ephemeral_key_midstate = Sha256::engine();
                ephemeral_key_midstate.input(ephemeral_random_data);

                let mut secp_ctx = Secp256k1::signing_only();
                let ephemeral_hash = Sha256::from_engine(ephemeral_key_midstate.clone()).into_inner();
                secp_ctx.seeded_randomize(&ephemeral_hash);

                PeerManager {
                        message_handler,
                        peers: FairRwLock::new(HashMap::new()),
                        node_id_to_descriptor: Mutex::new(HashMap::new()),
                        event_processing_lock: Mutex::new(()),
                        blocked_event_processors: AtomicBool::new(false),
                        our_node_secret,
                        ephemeral_key_midstate,
                        peer_counter: AtomicCounter::new(),
                        last_node_announcement_serial: AtomicU64::new(current_time),
                        logger,
                        custom_message_handler,
                        secp_ctx,
                }
        }

        /// Get the list of node ids for peers which have completed the initial handshake.
        ///
        /// For outbound connections, this will be the same as the their_node_id parameter passed in to
        /// new_outbound_connection, however entries will only appear once the initial handshake has
        /// completed and we are sure the remote peer has the private key for the given node_id.
        pub fn get_peer_node_ids(&self) -> Vec<PublicKey> {
                let peers = self.peers.read().unwrap();
                peers.values().filter_map(|peer_mutex| {
                        let p = peer_mutex.lock().unwrap();
                        if !p.channel_encryptor.is_ready_for_encryption() || p.their_features.is_none() {
                                return None;
                        }
                        p.their_node_id
                }).collect()
        }

        fn get_ephemeral_key(&self) -> SecretKey {
                let mut ephemeral_hash = self.ephemeral_key_midstate.clone();
                let counter = self.peer_counter.get_increment();
                ephemeral_hash.input(&counter.to_le_bytes());
                SecretKey::from_slice(&Sha256::from_engine(ephemeral_hash).into_inner()).expect("You broke SHA-256!")
        }

        /// Indicates a new outbound connection has been established to a node with the given node_id
        /// and an optional remote network address.
        ///
        /// The remote network address adds the option to report a remote IP address back to a connecting
        /// peer using the init message.
        /// The user should pass the remote network address of the host they are connected to.
        ///
        /// If an `Err` is returned here you must disconnect the connection immediately.
        ///
        /// Returns a small number of bytes to send to the remote node (currently always 50).
        ///
        /// Panics if descriptor is duplicative with some other descriptor which has not yet been
        /// [`socket_disconnected()`].
        ///
        /// [`socket_disconnected()`]: PeerManager::socket_disconnected
        pub fn new_outbound_connection(&self, their_node_id: PublicKey, descriptor: Descriptor, remote_network_address: Option<NetAddress>) -> Result<Vec<u8>, PeerHandleError> {
                let mut peer_encryptor = PeerChannelEncryptor::new_outbound(their_node_id.clone(), self.get_ephemeral_key());
                let res = peer_encryptor.get_act_one(&self.secp_ctx).to_vec();
                let pending_read_buffer = [0; 50].to_vec(); // Noise act two is 50 bytes

                let mut peers = self.peers.write().unwrap();
                if peers.insert(descriptor, Mutex::new(Peer {
                        channel_encryptor: peer_encryptor,
                        their_node_id: None,
                        their_features: None,
                        their_net_address: remote_network_address,

                        pending_outbound_buffer: LinkedList::new(),
                        pending_outbound_buffer_first_msg_offset: 0,
                        gossip_broadcast_buffer: LinkedList::new(),
                        awaiting_write_event: false,

                        pending_read_buffer,
                        pending_read_buffer_pos: 0,
                        pending_read_is_header: false,

                        sync_status: InitSyncTracker::NoSyncRequested,

                        msgs_sent_since_pong: 0,
                        awaiting_pong_timer_tick_intervals: 0,
                        received_message_since_timer_tick: false,
                        sent_gossip_timestamp_filter: false,
                })).is_some() {
                        panic!("PeerManager driver duplicated descriptors!");
                };
                Ok(res)
        }

        /// Indicates a new inbound connection has been established to a node with an optional remote
        /// network address.
        ///
        /// The remote network address adds the option to report a remote IP address back to a connecting
        /// peer using the init message.
        /// The user should pass the remote network address of the host they are connected to.
        ///
        /// May refuse the connection by returning an Err, but will never write bytes to the remote end
        /// (outbound connector always speaks first). If an `Err` is returned here you must disconnect
        /// the connection immediately.
        ///
        /// Panics if descriptor is duplicative with some other descriptor which has not yet been
        /// [`socket_disconnected()`].
        ///
        /// [`socket_disconnected()`]: PeerManager::socket_disconnected
        pub fn new_inbound_connection(&self, descriptor: Descriptor, remote_network_address: Option<NetAddress>) -> Result<(), PeerHandleError> {
                let peer_encryptor = PeerChannelEncryptor::new_inbound(&self.our_node_secret, &self.secp_ctx);
                let pending_read_buffer = [0; 50].to_vec(); // Noise act one is 50 bytes

                let mut peers = self.peers.write().unwrap();
                if peers.insert(descriptor, Mutex::new(Peer {
                        channel_encryptor: peer_encryptor,
                        their_node_id: None,
                        their_features: None,
                        their_net_address: remote_network_address,

                        pending_outbound_buffer: LinkedList::new(),
                        pending_outbound_buffer_first_msg_offset: 0,
                        gossip_broadcast_buffer: LinkedList::new(),
                        awaiting_write_event: false,

                        pending_read_buffer,
                        pending_read_buffer_pos: 0,
                        pending_read_is_header: false,

                        sync_status: InitSyncTracker::NoSyncRequested,

                        msgs_sent_since_pong: 0,
                        awaiting_pong_timer_tick_intervals: 0,
                        received_message_since_timer_tick: false,
                        sent_gossip_timestamp_filter: false,
                })).is_some() {
                        panic!("PeerManager driver duplicated descriptors!");
                };
                Ok(())
        }

        fn do_attempt_write_data(&self, descriptor: &mut Descriptor, peer: &mut Peer) {
                while !peer.awaiting_write_event {
                        if peer.should_buffer_onion_message() {
                                if let Some(peer_node_id) = peer.their_node_id {
                                        if let Some(next_onion_message) =
                                                self.message_handler.onion_message_handler.next_onion_message_for_peer(peer_node_id) {
                                                        self.enqueue_message(peer, &next_onion_message);
                                        }
                                }
                        }
                        if peer.should_buffer_gossip_broadcast() {
                                if let Some(msg) = peer.gossip_broadcast_buffer.pop_front() {
                                        peer.pending_outbound_buffer.push_back(msg);
                                }
                        }
                        if peer.should_buffer_gossip_backfill() {
                                match peer.sync_status {
                                        InitSyncTracker::NoSyncRequested => {},
                                        InitSyncTracker::ChannelsSyncing(c) if c < 0xffff_ffff_ffff_ffff => {
                                                if let Some((announce, update_a_option, update_b_option)) =
                                                        self.message_handler.route_handler.get_next_channel_announcement(c)
                                                {
                                                        self.enqueue_message(peer, &announce);
                                                        if let Some(update_a) = update_a_option {
                                                                self.enqueue_message(peer, &update_a);
                                                        }
                                                        if let Some(update_b) = update_b_option {
                                                                self.enqueue_message(peer, &update_b);
                                                        }
                                                        peer.sync_status = InitSyncTracker::ChannelsSyncing(announce.contents.short_channel_id + 1);
                                                } else {
                                                        peer.sync_status = InitSyncTracker::ChannelsSyncing(0xffff_ffff_ffff_ffff);
                                                }
                                        },
                                        InitSyncTracker::ChannelsSyncing(c) if c == 0xffff_ffff_ffff_ffff => {
                                                if let Some(msg) = self.message_handler.route_handler.get_next_node_announcement(None) {
                                                        self.enqueue_message(peer, &msg);
                                                        peer.sync_status = InitSyncTracker::NodesSyncing(msg.contents.node_id);
                                                } else {
                                                        peer.sync_status = InitSyncTracker::NoSyncRequested;
                                                }
                                        },
                                        InitSyncTracker::ChannelsSyncing(_) => unreachable!(),
                                        InitSyncTracker::NodesSyncing(key) => {
                                                if let Some(msg) = self.message_handler.route_handler.get_next_node_announcement(Some(&key)) {
                                                        self.enqueue_message(peer, &msg);
                                                        peer.sync_status = InitSyncTracker::NodesSyncing(msg.contents.node_id);
                                                } else {
                                                        peer.sync_status = InitSyncTracker::NoSyncRequested;
                                                }
                                        },
                                }
                        }
                        if peer.msgs_sent_since_pong >= BUFFER_DRAIN_MSGS_PER_TICK {
                                self.maybe_send_extra_ping(peer);
                        }

                        let next_buff = match peer.pending_outbound_buffer.front() {
                                None => return,
                                Some(buff) => buff,
                        };

                        let pending = &next_buff[peer.pending_outbound_buffer_first_msg_offset..];
                        let data_sent = descriptor.send_data(pending, peer.should_read());
                        peer.pending_outbound_buffer_first_msg_offset += data_sent;
                        if peer.pending_outbound_buffer_first_msg_offset == next_buff.len() {
                                peer.pending_outbound_buffer_first_msg_offset = 0;
                                peer.pending_outbound_buffer.pop_front();
                        } else {
                                peer.awaiting_write_event = true;
                        }
                }
        }

        /// Indicates that there is room to write data to the given socket descriptor.
        ///
        /// May return an Err to indicate that the connection should be closed.
        ///
        /// May call [`send_data`] on the descriptor passed in (or an equal descriptor) before
        /// returning. Thus, be very careful with reentrancy issues! The invariants around calling
        /// [`write_buffer_space_avail`] in case a write did not fully complete must still hold - be
        /// ready to call `[write_buffer_space_avail`] again if a write call generated here isn't
        /// sufficient!
        ///
        /// [`send_data`]: SocketDescriptor::send_data
        /// [`write_buffer_space_avail`]: PeerManager::write_buffer_space_avail
        pub fn write_buffer_space_avail(&self, descriptor: &mut Descriptor) -> Result<(), PeerHandleError> {
                let peers = self.peers.read().unwrap();
                match peers.get(descriptor) {
                        None => {
                                // This is most likely a simple race condition where the user found that the socket
                                // was writeable, then we told the user to `disconnect_socket()`, then they called
                                // this method. Return an error to make sure we get disconnected.
                                return Err(PeerHandleError { no_connection_possible: false });
                        },
                        Some(peer_mutex) => {
                                let mut peer = peer_mutex.lock().unwrap();
                                peer.awaiting_write_event = false;
                                self.do_attempt_write_data(descriptor, &mut peer);
                        }
                };
                Ok(())
        }

        /// Indicates that data was read from the given socket descriptor.
        ///
        /// May return an Err to indicate that the connection should be closed.
        ///
        /// Will *not* call back into [`send_data`] on any descriptors to avoid reentrancy complexity.
        /// Thus, however, you should call [`process_events`] after any `read_event` to generate
        /// [`send_data`] calls to handle responses.
        ///
        /// If `Ok(true)` is returned, further read_events should not be triggered until a
        /// [`send_data`] call on this descriptor has `resume_read` set (preventing DoS issues in the
        /// send buffer).
        ///
        /// [`send_data`]: SocketDescriptor::send_data
        /// [`process_events`]: PeerManager::process_events
        pub fn read_event(&self, peer_descriptor: &mut Descriptor, data: &[u8]) -> Result<bool, PeerHandleError> {
                match self.do_read_event(peer_descriptor, data) {
                        Ok(res) => Ok(res),
                        Err(e) => {
                                log_trace!(self.logger, "Peer sent invalid data or we decided to disconnect due to a protocol error");
                                self.disconnect_event_internal(peer_descriptor, e.no_connection_possible);
                                Err(e)
                        }
                }
        }

        /// Append a message to a peer's pending outbound/write buffer
        fn enqueue_message<M: wire::Type>(&self, peer: &mut Peer, message: &M) {
                let mut buffer = VecWriter(Vec::with_capacity(2048));
                wire::write(message, &mut buffer).unwrap(); // crash if the write failed

                if is_gossip_msg(message.type_id()) {
                        log_gossip!(self.logger, "Enqueueing message {:?} to {}", message, log_pubkey!(peer.their_node_id.unwrap()));
                } else {
                        log_trace!(self.logger, "Enqueueing message {:?} to {}", message, log_pubkey!(peer.their_node_id.unwrap()))
                }
                peer.msgs_sent_since_pong += 1;
                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&buffer.0[..]));
        }

        /// Append a message to a peer's pending outbound/write gossip broadcast buffer
        fn enqueue_encoded_gossip_broadcast(&self, peer: &mut Peer, encoded_message: &Vec<u8>) {
                peer.msgs_sent_since_pong += 1;
                peer.gossip_broadcast_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_message[..]));
        }

        fn do_read_event(&self, peer_descriptor: &mut Descriptor, data: &[u8]) -> Result<bool, PeerHandleError> {
                let mut pause_read = false;
                let peers = self.peers.read().unwrap();
                let mut msgs_to_forward = Vec::new();
                let mut peer_node_id = None;
                match peers.get(peer_descriptor) {
                        None => {
                                // This is most likely a simple race condition where the user read some bytes
                                // from the socket, then we told the user to `disconnect_socket()`, then they
                                // called this method. Return an error to make sure we get disconnected.
                                return Err(PeerHandleError { no_connection_possible: false });
                        },
                        Some(peer_mutex) => {
                                let mut read_pos = 0;
                                while read_pos < data.len() {
                                        macro_rules! try_potential_handleerror {
                                                ($peer: expr, $thing: expr) => {
                                                        match $thing {
                                                                Ok(x) => x,
                                                                Err(e) => {
                                                                        match e.action {
                                                                                msgs::ErrorAction::DisconnectPeer { msg: _ } => {
                                                                                        //TODO: Try to push msg
                                                                                        log_debug!(self.logger, "Error handling message{}; disconnecting peer with: {}", OptionalFromDebugger(&peer_node_id), e.err);
                                                                                        return Err(PeerHandleError{ no_connection_possible: false });
                                                                                },
                                                                                msgs::ErrorAction::IgnoreAndLog(level) => {
                                                                                        log_given_level!(self.logger, level, "Error handling message{}; ignoring: {}", OptionalFromDebugger(&peer_node_id), e.err);
                                                                                        continue
                                                                                },
                                                                                msgs::ErrorAction::IgnoreDuplicateGossip => continue, // Don't even bother logging these
                                                                                msgs::ErrorAction::IgnoreError => {
                                                                                        log_debug!(self.logger, "Error handling message{}; ignoring: {}", OptionalFromDebugger(&peer_node_id), e.err);
                                                                                        continue;
                                                                                },
                                                                                msgs::ErrorAction::SendErrorMessage { msg } => {
                                                                                        log_debug!(self.logger, "Error handling message{}; sending error message with: {}", OptionalFromDebugger(&peer_node_id), e.err);
                                                                                        self.enqueue_message($peer, &msg);
                                                                                        continue;
                                                                                },
                                                                                msgs::ErrorAction::SendWarningMessage { msg, log_level } => {
                                                                                        log_given_level!(self.logger, log_level, "Error handling message{}; sending warning message with: {}", OptionalFromDebugger(&peer_node_id), e.err);
                                                                                        self.enqueue_message($peer, &msg);
                                                                                        continue;
                                                                                },
                                                                        }
                                                                }
                                                        }
                                                }
                                        }

                                        let mut peer_lock = peer_mutex.lock().unwrap();
                                        let peer = &mut *peer_lock;
                                        let mut msg_to_handle = None;
                                        if peer_node_id.is_none() {
                                                peer_node_id = peer.their_node_id.clone();
                                        }

                                        assert!(peer.pending_read_buffer.len() > 0);
                                        assert!(peer.pending_read_buffer.len() > peer.pending_read_buffer_pos);

                                        {
                                                let data_to_copy = cmp::min(peer.pending_read_buffer.len() - peer.pending_read_buffer_pos, data.len() - read_pos);
                                                peer.pending_read_buffer[peer.pending_read_buffer_pos..peer.pending_read_buffer_pos + data_to_copy].copy_from_slice(&data[read_pos..read_pos + data_to_copy]);
                                                read_pos += data_to_copy;
                                                peer.pending_read_buffer_pos += data_to_copy;
                                        }

                                        if peer.pending_read_buffer_pos == peer.pending_read_buffer.len() {
                                                peer.pending_read_buffer_pos = 0;

                                                macro_rules! insert_node_id {
                                                        () => {
                                                                match self.node_id_to_descriptor.lock().unwrap().entry(peer.their_node_id.unwrap()) {
                                                                        hash_map::Entry::Occupied(_) => {
                                                                                log_trace!(self.logger, "Got second connection with {}, closing", log_pubkey!(peer.their_node_id.unwrap()));
                                                                                peer.their_node_id = None; // Unset so that we don't generate a peer_disconnected event
                                                                                return Err(PeerHandleError{ no_connection_possible: false })
                                                                        },
                                                                        hash_map::Entry::Vacant(entry) => {
                                                                                log_debug!(self.logger, "Finished noise handshake for connection with {}", log_pubkey!(peer.their_node_id.unwrap()));
                                                                                entry.insert(peer_descriptor.clone())
                                                                        },
                                                                };
                                                        }
                                                }

                                                let next_step = peer.channel_encryptor.get_noise_step();
                                                match next_step {
                                                        NextNoiseStep::ActOne => {
                                                                let act_two = try_potential_handleerror!(peer, peer.channel_encryptor
                                                                        .process_act_one_with_keys(&peer.pending_read_buffer[..],
                                                                                &self.our_node_secret, self.get_ephemeral_key(), &self.secp_ctx)).to_vec();
                                                                peer.pending_outbound_buffer.push_back(act_two);
                                                                peer.pending_read_buffer = [0; 66].to_vec(); // act three is 66 bytes long
                                                        },
                                                        NextNoiseStep::ActTwo => {
                                                                let (act_three, their_node_id) = try_potential_handleerror!(peer,
                                                                        peer.channel_encryptor.process_act_two(&peer.pending_read_buffer[..],
                                                                                &self.our_node_secret, &self.secp_ctx));
                                                                peer.pending_outbound_buffer.push_back(act_three.to_vec());
                                                                peer.pending_read_buffer = [0; 18].to_vec(); // Message length header is 18 bytes
                                                                peer.pending_read_is_header = true;

                                                                peer.their_node_id = Some(their_node_id);
                                                                insert_node_id!();
                                                                let features = self.message_handler.chan_handler.provided_init_features(&their_node_id)
                                                                        .or(self.message_handler.route_handler.provided_init_features(&their_node_id))
                                                                        .or(self.message_handler.onion_message_handler.provided_init_features(&their_node_id));
                                                                let resp = msgs::Init { features, remote_network_address: filter_addresses(peer.their_net_address.clone()) };
                                                                self.enqueue_message(peer, &resp);
                                                                peer.awaiting_pong_timer_tick_intervals = 0;
                                                        },
                                                        NextNoiseStep::ActThree => {
                                                                let their_node_id = try_potential_handleerror!(peer,
                                                                        peer.channel_encryptor.process_act_three(&peer.pending_read_buffer[..]));
                                                                peer.pending_read_buffer = [0; 18].to_vec(); // Message length header is 18 bytes
                                                                peer.pending_read_is_header = true;
                                                                peer.their_node_id = Some(their_node_id);
                                                                insert_node_id!();
                                                                let features = self.message_handler.chan_handler.provided_init_features(&their_node_id)
                                                                        .or(self.message_handler.route_handler.provided_init_features(&their_node_id))
                                                                        .or(self.message_handler.onion_message_handler.provided_init_features(&their_node_id));
                                                                let resp = msgs::Init { features, remote_network_address: filter_addresses(peer.their_net_address.clone()) };
                                                                self.enqueue_message(peer, &resp);
                                                                peer.awaiting_pong_timer_tick_intervals = 0;
                                                        },
                                                        NextNoiseStep::NoiseComplete => {
                                                                if peer.pending_read_is_header {
                                                                        let msg_len = try_potential_handleerror!(peer,
                                                                                peer.channel_encryptor.decrypt_length_header(&peer.pending_read_buffer[..]));
                                                                        if peer.pending_read_buffer.capacity() > 8192 { peer.pending_read_buffer = Vec::new(); }
                                                                        peer.pending_read_buffer.resize(msg_len as usize + 16, 0);
                                                                        if msg_len < 2 { // Need at least the message type tag
                                                                                return Err(PeerHandleError{ no_connection_possible: false });
                                                                        }
                                                                        peer.pending_read_is_header = false;
                                                                } else {
                                                                        let msg_data = try_potential_handleerror!(peer,
                                                                                peer.channel_encryptor.decrypt_message(&peer.pending_read_buffer[..]));
                                                                        assert!(msg_data.len() >= 2);

                                                                        // Reset read buffer
                                                                        if peer.pending_read_buffer.capacity() > 8192 { peer.pending_read_buffer = Vec::new(); }
                                                                        peer.pending_read_buffer.resize(18, 0);
                                                                        peer.pending_read_is_header = true;

                                                                        let mut reader = io::Cursor::new(&msg_data[..]);
                                                                        let message_result = wire::read(&mut reader, &*self.custom_message_handler);
                                                                        let message = match message_result {
                                                                                Ok(x) => x,
                                                                                Err(e) => {
                                                                                        match e {
                                                                                                // Note that to avoid recursion we never call
                                                                                                // `do_attempt_write_data` from here, causing
                                                                                                // the messages enqueued here to not actually
                                                                                                // be sent before the peer is disconnected.
                                                                                                (msgs::DecodeError::UnknownRequiredFeature, Some(ty)) if is_gossip_msg(ty) => {
                                                                                                        log_gossip!(self.logger, "Got a channel/node announcement with an unknown required feature flag, you may want to update!");
                                                                                                        continue;
                                                                                                }
                                                                                                (msgs::DecodeError::UnsupportedCompression, _) => {
                                                                                                        log_gossip!(self.logger, "We don't support zlib-compressed message fields, sending a warning and ignoring message");
                                                                                                        self.enqueue_message(peer, &msgs::WarningMessage { channel_id: [0; 32], data: "Unsupported message compression: zlib".to_owned() });
                                                                                                        continue;
                                                                                                }
                                                                                                (_, Some(ty)) if is_gossip_msg(ty) => {
                                                                                                        log_gossip!(self.logger, "Got an invalid value while deserializing a gossip message");
                                                                                                        self.enqueue_message(peer, &msgs::WarningMessage { channel_id: [0; 32], data: "Unreadable/bogus gossip message".to_owned() });
                                                                                                        continue;
                                                                                                }
                                                                                                (msgs::DecodeError::UnknownRequiredFeature, ty) => {
                                                                                                        log_gossip!(self.logger, "Received a message with an unknown required feature flag or TLV, you may want to update!");
                                                                                                        self.enqueue_message(peer, &msgs::WarningMessage { channel_id: [0; 32], data: format!("Received an unknown required feature/TLV in message type {:?}", ty) });
                                                                                                        return Err(PeerHandleError { no_connection_possible: false });
                                                                                                }
                                                                                                (msgs::DecodeError::UnknownVersion, _) => return Err(PeerHandleError { no_connection_possible: false }),
                                                                                                (msgs::DecodeError::InvalidValue, _) => {
                                                                                                        log_debug!(self.logger, "Got an invalid value while deserializing message");
                                                                                                        return Err(PeerHandleError { no_connection_possible: false });
                                                                                                }
                                                                                                (msgs::DecodeError::ShortRead, _) => {
                                                                                                        log_debug!(self.logger, "Deserialization failed due to shortness of message");
                                                                                                        return Err(PeerHandleError { no_connection_possible: false });
                                                                                                }
                                                                                                (msgs::DecodeError::BadLengthDescriptor, _) => return Err(PeerHandleError { no_connection_possible: false }),
                                                                                                (msgs::DecodeError::Io(_), _) => return Err(PeerHandleError { no_connection_possible: false }),
                                                                                        }
                                                                                }
                                                                        };

                                                                        msg_to_handle = Some(message);
                                                                }
                                                        }
                                                }
                                        }
                                        pause_read = !peer.should_read();

                                        if let Some(message) = msg_to_handle {
                                                match self.handle_message(&peer_mutex, peer_lock, message) {
                                                        Err(handling_error) => match handling_error {
                                                                MessageHandlingError::PeerHandleError(e) => { return Err(e) },
                                                                MessageHandlingError::LightningError(e) => {
                                                                        try_potential_handleerror!(&mut peer_mutex.lock().unwrap(), Err(e));
                                                                },
                                                        },
                                                        Ok(Some(msg)) => {
                                                                msgs_to_forward.push(msg);
                                                        },
                                                        Ok(None) => {},
                                                }
                                        }
                                }
                        }
                }

                for msg in msgs_to_forward.drain(..) {
                        self.forward_broadcast_msg(&*peers, &msg, peer_node_id.as_ref());
                }

                Ok(pause_read)
        }

        /// Process an incoming message and return a decision (ok, lightning error, peer handling error) regarding the next action with the peer
        /// Returns the message back if it needs to be broadcasted to all other peers.
        fn handle_message(
                &self,
                peer_mutex: &Mutex<Peer>,
                mut peer_lock: MutexGuard<Peer>,
                message: wire::Message<<<CMH as core::ops::Deref>::Target as wire::CustomMessageReader>::CustomMessage>
        ) -> Result<Option<wire::Message<<<CMH as core::ops::Deref>::Target as wire::CustomMessageReader>::CustomMessage>>, MessageHandlingError> {
                let their_node_id = peer_lock.their_node_id.clone().expect("We know the peer's public key by the time we receive messages");
                peer_lock.received_message_since_timer_tick = true;

                // Need an Init as first message
                if let wire::Message::Init(msg) = message {
                        if msg.features.requires_unknown_bits() {
                                log_debug!(self.logger, "Peer features required unknown version bits");
                                return Err(PeerHandleError{ no_connection_possible: true }.into());
                        }
                        if peer_lock.their_features.is_some() {
                                return Err(PeerHandleError{ no_connection_possible: false }.into());
                        }

                        log_info!(self.logger, "Received peer Init message from {}: {}", log_pubkey!(their_node_id), msg.features);

                        // For peers not supporting gossip queries start sync now, otherwise wait until we receive a filter.
                        if msg.features.initial_routing_sync() && !msg.features.supports_gossip_queries() {
                                peer_lock.sync_status = InitSyncTracker::ChannelsSyncing(0);
                        }

                        if !msg.features.supports_static_remote_key() {
                                log_debug!(self.logger, "Peer {} does not support static remote key, disconnecting with no_connection_possible", log_pubkey!(their_node_id));
                                return Err(PeerHandleError{ no_connection_possible: true }.into());
                        }

                        self.message_handler.route_handler.peer_connected(&their_node_id, &msg);
                        self.message_handler.chan_handler.peer_connected(&their_node_id, &msg);
                        self.message_handler.onion_message_handler.peer_connected(&their_node_id, &msg);

                        peer_lock.their_features = Some(msg.features);
                        return Ok(None);
                } else if peer_lock.their_features.is_none() {
                        log_debug!(self.logger, "Peer {} sent non-Init first message", log_pubkey!(their_node_id));
                        return Err(PeerHandleError{ no_connection_possible: false }.into());
                }

                if let wire::Message::GossipTimestampFilter(_msg) = message {
                        // When supporting gossip messages, start inital gossip sync only after we receive
                        // a GossipTimestampFilter
                        if peer_lock.their_features.as_ref().unwrap().supports_gossip_queries() &&
                                !peer_lock.sent_gossip_timestamp_filter {
                                peer_lock.sent_gossip_timestamp_filter = true;
                                peer_lock.sync_status = InitSyncTracker::ChannelsSyncing(0);
                        }
                        return Ok(None);
                }

                let their_features = peer_lock.their_features.clone();
                mem::drop(peer_lock);

                if is_gossip_msg(message.type_id()) {
                        log_gossip!(self.logger, "Received message {:?} from {}", message, log_pubkey!(their_node_id));
                } else {
                        log_trace!(self.logger, "Received message {:?} from {}", message, log_pubkey!(their_node_id));
                }

                let mut should_forward = None;

                match message {
                        // Setup and Control messages:
                        wire::Message::Init(_) => {
                                // Handled above
                        },
                        wire::Message::GossipTimestampFilter(_) => {
                                // Handled above
                        },
                        wire::Message::Error(msg) => {
                                let mut data_is_printable = true;
                                for b in msg.data.bytes() {
                                        if b < 32 || b > 126 {
                                                data_is_printable = false;
                                                break;
                                        }
                                }

                                if data_is_printable {
                                        log_debug!(self.logger, "Got Err message from {}: {}", log_pubkey!(their_node_id), msg.data);
                                } else {
                                        log_debug!(self.logger, "Got Err message from {} with non-ASCII error message", log_pubkey!(their_node_id));
                                }
                                self.message_handler.chan_handler.handle_error(&their_node_id, &msg);
                                if msg.channel_id == [0; 32] {
                                        return Err(PeerHandleError{ no_connection_possible: true }.into());
                                }
                        },
                        wire::Message::Warning(msg) => {
                                let mut data_is_printable = true;
                                for b in msg.data.bytes() {
                                        if b < 32 || b > 126 {
                                                data_is_printable = false;
                                                break;
                                        }
                                }

                                if data_is_printable {
                                        log_debug!(self.logger, "Got warning message from {}: {}", log_pubkey!(their_node_id), msg.data);
                                } else {
                                        log_debug!(self.logger, "Got warning message from {} with non-ASCII error message", log_pubkey!(their_node_id));
                                }
                        },

                        wire::Message::Ping(msg) => {
                                if msg.ponglen < 65532 {
                                        let resp = msgs::Pong { byteslen: msg.ponglen };
                                        self.enqueue_message(&mut *peer_mutex.lock().unwrap(), &resp);
                                }
                        },
                        wire::Message::Pong(_msg) => {
                                let mut peer_lock = peer_mutex.lock().unwrap();
                                peer_lock.awaiting_pong_timer_tick_intervals = 0;
                                peer_lock.msgs_sent_since_pong = 0;
                        },

                        // Channel messages:
                        wire::Message::OpenChannel(msg) => {
                                self.message_handler.chan_handler.handle_open_channel(&their_node_id, their_features.clone().unwrap(), &msg);
                        },
                        wire::Message::AcceptChannel(msg) => {
                                self.message_handler.chan_handler.handle_accept_channel(&their_node_id, their_features.clone().unwrap(), &msg);
                        },

                        wire::Message::FundingCreated(msg) => {
                                self.message_handler.chan_handler.handle_funding_created(&their_node_id, &msg);
                        },
                        wire::Message::FundingSigned(msg) => {
                                self.message_handler.chan_handler.handle_funding_signed(&their_node_id, &msg);
                        },
                        wire::Message::ChannelReady(msg) => {
                                self.message_handler.chan_handler.handle_channel_ready(&their_node_id, &msg);
                        },

                        wire::Message::Shutdown(msg) => {
                                self.message_handler.chan_handler.handle_shutdown(&their_node_id, their_features.as_ref().unwrap(), &msg);
                        },
                        wire::Message::ClosingSigned(msg) => {
                                self.message_handler.chan_handler.handle_closing_signed(&their_node_id, &msg);
                        },

                        // Commitment messages:
                        wire::Message::UpdateAddHTLC(msg) => {
                                self.message_handler.chan_handler.handle_update_add_htlc(&their_node_id, &msg);
                        },
                        wire::Message::UpdateFulfillHTLC(msg) => {
                                self.message_handler.chan_handler.handle_update_fulfill_htlc(&their_node_id, &msg);
                        },
                        wire::Message::UpdateFailHTLC(msg) => {
                                self.message_handler.chan_handler.handle_update_fail_htlc(&their_node_id, &msg);
                        },
                        wire::Message::UpdateFailMalformedHTLC(msg) => {
                                self.message_handler.chan_handler.handle_update_fail_malformed_htlc(&their_node_id, &msg);
                        },

                        wire::Message::CommitmentSigned(msg) => {
                                self.message_handler.chan_handler.handle_commitment_signed(&their_node_id, &msg);
                        },
                        wire::Message::RevokeAndACK(msg) => {
                                self.message_handler.chan_handler.handle_revoke_and_ack(&their_node_id, &msg);
                        },
                        wire::Message::UpdateFee(msg) => {
                                self.message_handler.chan_handler.handle_update_fee(&their_node_id, &msg);
                        },
                        wire::Message::ChannelReestablish(msg) => {
                                self.message_handler.chan_handler.handle_channel_reestablish(&their_node_id, &msg);
                        },

                        // Routing messages:
                        wire::Message::AnnouncementSignatures(msg) => {
                                self.message_handler.chan_handler.handle_announcement_signatures(&their_node_id, &msg);
                        },
                        wire::Message::ChannelAnnouncement(msg) => {
                                if self.message_handler.route_handler.handle_channel_announcement(&msg)
                                                .map_err(|e| -> MessageHandlingError { e.into() })? {
                                        should_forward = Some(wire::Message::ChannelAnnouncement(msg));
                                }
                        },
                        wire::Message::NodeAnnouncement(msg) => {
                                if self.message_handler.route_handler.handle_node_announcement(&msg)
                                                .map_err(|e| -> MessageHandlingError { e.into() })? {
                                        should_forward = Some(wire::Message::NodeAnnouncement(msg));
                                }
                        },
                        wire::Message::ChannelUpdate(msg) => {
                                self.message_handler.chan_handler.handle_channel_update(&their_node_id, &msg);
                                if self.message_handler.route_handler.handle_channel_update(&msg)
                                                .map_err(|e| -> MessageHandlingError { e.into() })? {
                                        should_forward = Some(wire::Message::ChannelUpdate(msg));
                                }
                        },
                        wire::Message::QueryShortChannelIds(msg) => {
                                self.message_handler.route_handler.handle_query_short_channel_ids(&their_node_id, msg)?;
                        },
                        wire::Message::ReplyShortChannelIdsEnd(msg) => {
                                self.message_handler.route_handler.handle_reply_short_channel_ids_end(&their_node_id, msg)?;
                        },
                        wire::Message::QueryChannelRange(msg) => {
                                self.message_handler.route_handler.handle_query_channel_range(&their_node_id, msg)?;
                        },
                        wire::Message::ReplyChannelRange(msg) => {
                                self.message_handler.route_handler.handle_reply_channel_range(&their_node_id, msg)?;
                        },

                        // Onion message:
                        wire::Message::OnionMessage(msg) => {
                                self.message_handler.onion_message_handler.handle_onion_message(&their_node_id, &msg);
                        },

                        // Unknown messages:
                        wire::Message::Unknown(type_id) if message.is_even() => {
                                log_debug!(self.logger, "Received unknown even message of type {}, disconnecting peer!", type_id);
                                // Fail the channel if message is an even, unknown type as per BOLT #1.
                                return Err(PeerHandleError{ no_connection_possible: true }.into());
                        },
                        wire::Message::Unknown(type_id) => {
                                log_trace!(self.logger, "Received unknown odd message of type {}, ignoring", type_id);
                        },
                        wire::Message::Custom(custom) => {
                                self.custom_message_handler.handle_custom_message(custom, &their_node_id)?;
                        },
                };
                Ok(should_forward)
        }

        fn forward_broadcast_msg(&self, peers: &HashMap<Descriptor, Mutex<Peer>>, msg: &wire::Message<<<CMH as core::ops::Deref>::Target as wire::CustomMessageReader>::CustomMessage>, except_node: Option<&PublicKey>) {
                match msg {
                        wire::Message::ChannelAnnouncement(ref msg) => {
                                log_gossip!(self.logger, "Sending message to all peers except {:?} or the announced channel's counterparties: {:?}", except_node, msg);
                                let encoded_msg = encode_msg!(msg);

                                for (_, peer_mutex) in peers.iter() {
                                        let mut peer = peer_mutex.lock().unwrap();
                                        if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
                                                        !peer.should_forward_channel_announcement(msg.contents.short_channel_id) {
                                                continue
                                        }
                                        if peer.buffer_full_drop_gossip_broadcast() {
                                                log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
                                                continue;
                                        }
                                        if peer.their_node_id.as_ref() == Some(&msg.contents.node_id_1) ||
                                           peer.their_node_id.as_ref() == Some(&msg.contents.node_id_2) {
                                                continue;
                                        }
                                        if except_node.is_some() && peer.their_node_id.as_ref() == except_node {
                                                continue;
                                        }
                                        self.enqueue_encoded_gossip_broadcast(&mut *peer, &encoded_msg);
                                }
                        },
                        wire::Message::NodeAnnouncement(ref msg) => {
                                log_gossip!(self.logger, "Sending message to all peers except {:?} or the announced node: {:?}", except_node, msg);
                                let encoded_msg = encode_msg!(msg);

                                for (_, peer_mutex) in peers.iter() {
                                        let mut peer = peer_mutex.lock().unwrap();
                                        if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
                                                        !peer.should_forward_node_announcement(msg.contents.node_id) {
                                                continue
                                        }
                                        if peer.buffer_full_drop_gossip_broadcast() {
                                                log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
                                                continue;
                                        }
                                        if peer.their_node_id.as_ref() == Some(&msg.contents.node_id) {
                                                continue;
                                        }
                                        if except_node.is_some() && peer.their_node_id.as_ref() == except_node {
                                                continue;
                                        }
                                        self.enqueue_encoded_gossip_broadcast(&mut *peer, &encoded_msg);
                                }
                        },
                        wire::Message::ChannelUpdate(ref msg) => {
                                log_gossip!(self.logger, "Sending message to all peers except {:?}: {:?}", except_node, msg);
                                let encoded_msg = encode_msg!(msg);

                                for (_, peer_mutex) in peers.iter() {
                                        let mut peer = peer_mutex.lock().unwrap();
                                        if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
                                                        !peer.should_forward_channel_announcement(msg.contents.short_channel_id)  {
                                                continue
                                        }
                                        if peer.buffer_full_drop_gossip_broadcast() {
                                                log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
                                                continue;
                                        }
                                        if except_node.is_some() && peer.their_node_id.as_ref() == except_node {
                                                continue;
                                        }
                                        self.enqueue_encoded_gossip_broadcast(&mut *peer, &encoded_msg);
                                }
                        },
                        _ => debug_assert!(false, "We shouldn't attempt to forward anything but gossip messages"),
                }
        }

        /// Checks for any events generated by our handlers and processes them. Includes sending most
        /// response messages as well as messages generated by calls to handler functions directly (eg
        /// functions like [`ChannelManager::process_pending_htlc_forwards`] or [`send_payment`]).
        ///
        /// May call [`send_data`] on [`SocketDescriptor`]s. Thus, be very careful with reentrancy
        /// issues!
        ///
        /// You don't have to call this function explicitly if you are using [`lightning-net-tokio`]
        /// or one of the other clients provided in our language bindings.
        ///
        /// Note that if there are any other calls to this function waiting on lock(s) this may return
        /// without doing any work. All available events that need handling will be handled before the
        /// other calls return.
        ///
        /// [`send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
        /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
        /// [`send_data`]: SocketDescriptor::send_data
        pub fn process_events(&self) {
                let mut _single_processor_lock = self.event_processing_lock.try_lock();
                if _single_processor_lock.is_err() {
                        // While we could wake the older sleeper here with a CV and make more even waiting
                        // times, that would be a lot of overengineering for a simple "reduce total waiter
                        // count" goal.
                        match self.blocked_event_processors.compare_exchange(false, true, Ordering::AcqRel, Ordering::Acquire) {
                                Err(val) => {
                                        debug_assert!(val, "compare_exchange failed spuriously?");
                                        return;
                                },
                                Ok(val) => {
                                        debug_assert!(!val, "compare_exchange succeeded spuriously?");
                                        // We're the only waiter, as the running process_events may have emptied the
                                        // pending events "long" ago and there are new events for us to process, wait until
                                        // its done and process any leftover events before returning.
                                        _single_processor_lock = Ok(self.event_processing_lock.lock().unwrap());
                                        self.blocked_event_processors.store(false, Ordering::Release);
                                }
                        }
                }

                let mut peers_to_disconnect = HashMap::new();
                let mut events_generated = self.message_handler.chan_handler.get_and_clear_pending_msg_events();
                events_generated.append(&mut self.message_handler.route_handler.get_and_clear_pending_msg_events());

                {
                        // TODO: There are some DoS attacks here where you can flood someone's outbound send
                        // buffer by doing things like announcing channels on another node. We should be willing to
                        // drop optional-ish messages when send buffers get full!

                        let peers_lock = self.peers.read().unwrap();
                        let peers = &*peers_lock;
                        macro_rules! get_peer_for_forwarding {
                                ($node_id: expr) => {
                                        {
                                                if peers_to_disconnect.get($node_id).is_some() {
                                                        // If we've "disconnected" this peer, do not send to it.
                                                        continue;
                                                }
                                                let descriptor_opt = self.node_id_to_descriptor.lock().unwrap().get($node_id).cloned();
                                                match descriptor_opt {
                                                        Some(descriptor) => match peers.get(&descriptor) {
                                                                Some(peer_mutex) => {
                                                                        let peer_lock = peer_mutex.lock().unwrap();
                                                                        if peer_lock.their_features.is_none() {
                                                                                continue;
                                                                        }
                                                                        peer_lock
                                                                },
                                                                None => {
                                                                        debug_assert!(false, "Inconsistent peers set state!");
                                                                        continue;
                                                                }
                                                        },
                                                        None => {
                                                                continue;
                                                        },
                                                }
                                        }
                                }
                        }
                        for event in events_generated.drain(..) {
                                match event {
                                        MessageSendEvent::SendAcceptChannel { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendAcceptChannel event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.temporary_channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendOpenChannel { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendOpenChannel event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.temporary_channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendFundingCreated { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendFundingCreated event in peer_handler for node {} for channel {} (which becomes {})",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.temporary_channel_id),
                                                                log_funding_channel_id!(msg.funding_txid, msg.funding_output_index));
                                                // TODO: If the peer is gone we should generate a DiscardFunding event
                                                // indicating to the wallet that they should just throw away this funding transaction
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendFundingSigned { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendFundingSigned event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendChannelReady { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendChannelReady event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendAnnouncementSignatures { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendAnnouncementSignatures event in peer_handler for node {} for channel {})",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::UpdateHTLCs { ref node_id, updates: msgs::CommitmentUpdate { ref update_add_htlcs, ref update_fulfill_htlcs, ref update_fail_htlcs, ref update_fail_malformed_htlcs, ref update_fee, ref commitment_signed } } => {
                                                log_debug!(self.logger, "Handling UpdateHTLCs event in peer_handler for node {} with {} adds, {} fulfills, {} fails for channel {}",
                                                                log_pubkey!(node_id),
                                                                update_add_htlcs.len(),
                                                                update_fulfill_htlcs.len(),
                                                                update_fail_htlcs.len(),
                                                                log_bytes!(commitment_signed.channel_id));
                                                let mut peer = get_peer_for_forwarding!(node_id);
                                                for msg in update_add_htlcs {
                                                        self.enqueue_message(&mut *peer, msg);
                                                }
                                                for msg in update_fulfill_htlcs {
                                                        self.enqueue_message(&mut *peer, msg);
                                                }
                                                for msg in update_fail_htlcs {
                                                        self.enqueue_message(&mut *peer, msg);
                                                }
                                                for msg in update_fail_malformed_htlcs {
                                                        self.enqueue_message(&mut *peer, msg);
                                                }
                                                if let &Some(ref msg) = update_fee {
                                                        self.enqueue_message(&mut *peer, msg);
                                                }
                                                self.enqueue_message(&mut *peer, commitment_signed);
                                        },
                                        MessageSendEvent::SendRevokeAndACK { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendRevokeAndACK event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendClosingSigned { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendClosingSigned event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendShutdown { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling Shutdown event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendChannelReestablish { ref node_id, ref msg } => {
                                                log_debug!(self.logger, "Handling SendChannelReestablish event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendChannelAnnouncement { ref node_id, ref msg, ref update_msg } => {
                                                log_debug!(self.logger, "Handling SendChannelAnnouncement event in peer_handler for node {} for short channel id {}",
                                                                log_pubkey!(node_id),
                                                                msg.contents.short_channel_id);
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), update_msg);
                                        },
                                        MessageSendEvent::BroadcastChannelAnnouncement { msg, update_msg } => {
                                                log_debug!(self.logger, "Handling BroadcastChannelAnnouncement event in peer_handler for short channel id {}", msg.contents.short_channel_id);
                                                match self.message_handler.route_handler.handle_channel_announcement(&msg) {
                                                        Ok(_) | Err(LightningError { action: msgs::ErrorAction::IgnoreDuplicateGossip, .. }) =>
                                                                self.forward_broadcast_msg(peers, &wire::Message::ChannelAnnouncement(msg), None),
                                                        _ => {},
                                                }
                                                match self.message_handler.route_handler.handle_channel_update(&update_msg) {
                                                        Ok(_) | Err(LightningError { action: msgs::ErrorAction::IgnoreDuplicateGossip, .. }) =>
                                                                self.forward_broadcast_msg(peers, &wire::Message::ChannelUpdate(update_msg), None),
                                                        _ => {},
                                                }
                                        },
                                        MessageSendEvent::BroadcastChannelUpdate { msg } => {
                                                log_debug!(self.logger, "Handling BroadcastChannelUpdate event in peer_handler for short channel id {}", msg.contents.short_channel_id);
                                                match self.message_handler.route_handler.handle_channel_update(&msg) {
                                                        Ok(_) | Err(LightningError { action: msgs::ErrorAction::IgnoreDuplicateGossip, .. }) =>
                                                                self.forward_broadcast_msg(peers, &wire::Message::ChannelUpdate(msg), None),
                                                        _ => {},
                                                }
                                        },
                                        MessageSendEvent::SendChannelUpdate { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendChannelUpdate event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id), msg.contents.short_channel_id);
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::HandleError { ref node_id, ref action } => {
                                                match *action {
                                                        msgs::ErrorAction::DisconnectPeer { ref msg } => {
                                                                // We do not have the peers write lock, so we just store that we're
                                                                // about to disconenct the peer and do it after we finish
                                                                // processing most messages.
                                                                peers_to_disconnect.insert(*node_id, msg.clone());
                                                        },
                                                        msgs::ErrorAction::IgnoreAndLog(level) => {
                                                                log_given_level!(self.logger, level, "Received a HandleError event to be ignored for node {}", log_pubkey!(node_id));
                                                        },
                                                        msgs::ErrorAction::IgnoreDuplicateGossip => {},
                                                        msgs::ErrorAction::IgnoreError => {
                                                                log_debug!(self.logger, "Received a HandleError event to be ignored for node {}", log_pubkey!(node_id));
                                                        },
                                                        msgs::ErrorAction::SendErrorMessage { ref msg } => {
                                                                log_trace!(self.logger, "Handling SendErrorMessage HandleError event in peer_handler for node {} with message {}",
                                                                                log_pubkey!(node_id),
                                                                                msg.data);
                                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                                        },
                                                        msgs::ErrorAction::SendWarningMessage { ref msg, ref log_level } => {
                                                                log_given_level!(self.logger, *log_level, "Handling SendWarningMessage HandleError event in peer_handler for node {} with message {}",
                                                                                log_pubkey!(node_id),
                                                                                msg.data);
                                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                                        },
                                                }
                                        },
                                        MessageSendEvent::SendChannelRangeQuery { ref node_id, ref msg } => {
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        },
                                        MessageSendEvent::SendShortIdsQuery { ref node_id, ref msg } => {
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        }
                                        MessageSendEvent::SendReplyChannelRange { ref node_id, ref msg } => {
                                                log_gossip!(self.logger, "Handling SendReplyChannelRange event in peer_handler for node {} with num_scids={} first_blocknum={} number_of_blocks={}, sync_complete={}",
                                                        log_pubkey!(node_id),
                                                        msg.short_channel_ids.len(),
                                                        msg.first_blocknum,
                                                        msg.number_of_blocks,
                                                        msg.sync_complete);
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        }
                                        MessageSendEvent::SendGossipTimestampFilter { ref node_id, ref msg } => {
                                                self.enqueue_message(&mut *get_peer_for_forwarding!(node_id), msg);
                                        }
                                }
                        }

                        for (node_id, msg) in self.custom_message_handler.get_and_clear_pending_msg() {
                                if peers_to_disconnect.get(&node_id).is_some() { continue; }
                                self.enqueue_message(&mut *get_peer_for_forwarding!(&node_id), &msg);
                        }

                        for (descriptor, peer_mutex) in peers.iter() {
                                self.do_attempt_write_data(&mut (*descriptor).clone(), &mut *peer_mutex.lock().unwrap());
                        }
                }
                if !peers_to_disconnect.is_empty() {
                        let mut peers_lock = self.peers.write().unwrap();
                        let peers = &mut *peers_lock;
                        for (node_id, msg) in peers_to_disconnect.drain() {
                                // Note that since we are holding the peers *write* lock we can
                                // remove from node_id_to_descriptor immediately (as no other
                                // thread can be holding the peer lock if we have the global write
                                // lock).

                                if let Some(mut descriptor) = self.node_id_to_descriptor.lock().unwrap().remove(&node_id) {
                                        if let Some(peer_mutex) = peers.remove(&descriptor) {
                                                if let Some(msg) = msg {
                                                        log_trace!(self.logger, "Handling DisconnectPeer HandleError event in peer_handler for node {} with message {}",
                                                                        log_pubkey!(node_id),
                                                                        msg.data);
                                                        let mut peer = peer_mutex.lock().unwrap();
                                                        self.enqueue_message(&mut *peer, &msg);
                                                        // This isn't guaranteed to work, but if there is enough free
                                                        // room in the send buffer, put the error message there...
                                                        self.do_attempt_write_data(&mut descriptor, &mut *peer);
                                                } else {
                                                        log_trace!(self.logger, "Handling DisconnectPeer HandleError event in peer_handler for node {} with no message", log_pubkey!(node_id));
                                                }
                                        }
                                        descriptor.disconnect_socket();
                                        self.message_handler.chan_handler.peer_disconnected(&node_id, false);
                                        self.message_handler.onion_message_handler.peer_disconnected(&node_id, false);
                                }
                        }
                }
        }

        /// Indicates that the given socket descriptor's connection is now closed.
        pub fn socket_disconnected(&self, descriptor: &Descriptor) {
                self.disconnect_event_internal(descriptor, false);
        }

        fn disconnect_event_internal(&self, descriptor: &Descriptor, no_connection_possible: bool) {
                let mut peers = self.peers.write().unwrap();
                let peer_option = peers.remove(descriptor);
                match peer_option {
                        None => {
                                // This is most likely a simple race condition where the user found that the socket
                                // was disconnected, then we told the user to `disconnect_socket()`, then they
                                // called this method. Either way we're disconnected, return.
                        },
                        Some(peer_lock) => {
                                let peer = peer_lock.lock().unwrap();
                                if let Some(node_id) = peer.their_node_id {
                                        log_trace!(self.logger,
                                                "Handling disconnection of peer {}, with {}future connection to the peer possible.",
                                                log_pubkey!(node_id), if no_connection_possible { "no " } else { "" });
                                        self.node_id_to_descriptor.lock().unwrap().remove(&node_id);
                                        self.message_handler.chan_handler.peer_disconnected(&node_id, no_connection_possible);
                                        self.message_handler.onion_message_handler.peer_disconnected(&node_id, no_connection_possible);
                                }
                        }
                };
        }

        /// Disconnect a peer given its node id.
        ///
        /// Set `no_connection_possible` to true to prevent any further connection with this peer,
        /// force-closing any channels we have with it.
        ///
        /// If a peer is connected, this will call [`disconnect_socket`] on the descriptor for the
        /// peer. Thus, be very careful about reentrancy issues.
        ///
        /// [`disconnect_socket`]: SocketDescriptor::disconnect_socket
        pub fn disconnect_by_node_id(&self, node_id: PublicKey, no_connection_possible: bool) {
                let mut peers_lock = self.peers.write().unwrap();
                if let Some(mut descriptor) = self.node_id_to_descriptor.lock().unwrap().remove(&node_id) {
                        log_trace!(self.logger, "Disconnecting peer with id {} due to client request", node_id);
                        peers_lock.remove(&descriptor);
                        self.message_handler.chan_handler.peer_disconnected(&node_id, no_connection_possible);
                        self.message_handler.onion_message_handler.peer_disconnected(&node_id, no_connection_possible);
                        descriptor.disconnect_socket();
                }
        }

        /// Disconnects all currently-connected peers. This is useful on platforms where there may be
        /// an indication that TCP sockets have stalled even if we weren't around to time them out
        /// using regular ping/pongs.
        pub fn disconnect_all_peers(&self) {
                let mut peers_lock = self.peers.write().unwrap();
                self.node_id_to_descriptor.lock().unwrap().clear();
                let peers = &mut *peers_lock;
                for (mut descriptor, peer) in peers.drain() {
                        if let Some(node_id) = peer.lock().unwrap().their_node_id {
                                log_trace!(self.logger, "Disconnecting peer with id {} due to client request to disconnect all peers", node_id);
                                self.message_handler.chan_handler.peer_disconnected(&node_id, false);
                                self.message_handler.onion_message_handler.peer_disconnected(&node_id, false);
                        }
                        descriptor.disconnect_socket();
                }
        }

        /// This is called when we're blocked on sending additional gossip messages until we receive a
        /// pong. If we aren't waiting on a pong, we take this opportunity to send a ping (setting
        /// `awaiting_pong_timer_tick_intervals` to a special flag value to indicate this).
        fn maybe_send_extra_ping(&self, peer: &mut Peer) {
                if peer.awaiting_pong_timer_tick_intervals == 0 {
                        peer.awaiting_pong_timer_tick_intervals = -1;
                        let ping = msgs::Ping {
                                ponglen: 0,
                                byteslen: 64,
                        };
                        self.enqueue_message(peer, &ping);
                }
        }

        /// Send pings to each peer and disconnect those which did not respond to the last round of
        /// pings.
        ///
        /// This may be called on any timescale you want, however, roughly once every ten seconds is
        /// preferred. The call rate determines both how often we send a ping to our peers and how much
        /// time they have to respond before we disconnect them.
        ///
        /// May call [`send_data`] on all [`SocketDescriptor`]s. Thus, be very careful with reentrancy
        /// issues!
        ///
        /// [`send_data`]: SocketDescriptor::send_data
        pub fn timer_tick_occurred(&self) {
                let mut descriptors_needing_disconnect = Vec::new();
                {
                        let peers_lock = self.peers.read().unwrap();

                        for (descriptor, peer_mutex) in peers_lock.iter() {
                                let mut peer = peer_mutex.lock().unwrap();
                                if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_node_id.is_none() {
                                        // The peer needs to complete its handshake before we can exchange messages. We
                                        // give peers one timer tick to complete handshake, reusing
                                        // `awaiting_pong_timer_tick_intervals` to track number of timer ticks taken
                                        // for handshake completion.
                                        if peer.awaiting_pong_timer_tick_intervals != 0 {
                                                descriptors_needing_disconnect.push(descriptor.clone());
                                        } else {
                                                peer.awaiting_pong_timer_tick_intervals = 1;
                                        }
                                        continue;
                                }

                                if peer.awaiting_pong_timer_tick_intervals == -1 {
                                        // Magic value set in `maybe_send_extra_ping`.
                                        peer.awaiting_pong_timer_tick_intervals = 1;
                                        peer.received_message_since_timer_tick = false;
                                        continue;
                                }

                                if (peer.awaiting_pong_timer_tick_intervals > 0 && !peer.received_message_since_timer_tick)
                                        || peer.awaiting_pong_timer_tick_intervals as u64 >
                                                MAX_BUFFER_DRAIN_TICK_INTERVALS_PER_PEER as u64 * peers_lock.len() as u64
                                {
                                        descriptors_needing_disconnect.push(descriptor.clone());
                                        continue;
                                }
                                peer.received_message_since_timer_tick = false;

                                if peer.awaiting_pong_timer_tick_intervals > 0 {
                                        peer.awaiting_pong_timer_tick_intervals += 1;
                                        continue;
                                }

                                peer.awaiting_pong_timer_tick_intervals = 1;
                                let ping = msgs::Ping {
                                        ponglen: 0,
                                        byteslen: 64,
                                };
                                self.enqueue_message(&mut *peer, &ping);
                                self.do_attempt_write_data(&mut (descriptor.clone()), &mut *peer);
                        }
                }

                if !descriptors_needing_disconnect.is_empty() {
                        {
                                let mut peers_lock = self.peers.write().unwrap();
                                for descriptor in descriptors_needing_disconnect.iter() {
                                        if let Some(peer) = peers_lock.remove(descriptor) {
                                                if let Some(node_id) = peer.lock().unwrap().their_node_id {
                                                        log_trace!(self.logger, "Disconnecting peer with id {} due to ping timeout", node_id);
                                                        self.node_id_to_descriptor.lock().unwrap().remove(&node_id);
                                                        self.message_handler.chan_handler.peer_disconnected(&node_id, false);
                                                        self.message_handler.onion_message_handler.peer_disconnected(&node_id, false);
                                                }
                                        }
                                }
                        }

                        for mut descriptor in descriptors_needing_disconnect.drain(..) {
                                descriptor.disconnect_socket();
                        }
                }
        }

        #[allow(dead_code)]
        // Messages of up to 64KB should never end up more than half full with addresses, as that would
        // be absurd. We ensure this by checking that at least 100 (our stated public contract on when
        // broadcast_node_announcement panics) of the maximum-length addresses would fit in a 64KB
        // message...
        const HALF_MESSAGE_IS_ADDRS: u32 = ::core::u16::MAX as u32 / (NetAddress::MAX_LEN as u32 + 1) / 2;
        #[deny(const_err)]
        #[allow(dead_code)]
        // ...by failing to compile if the number of addresses that would be half of a message is
        // smaller than 100:
        const STATIC_ASSERT: u32 = Self::HALF_MESSAGE_IS_ADDRS - 100;

        /// Generates a signed node_announcement from the given arguments, sending it to all connected
        /// peers. Note that peers will likely ignore this message unless we have at least one public
        /// channel which has at least six confirmations on-chain.
        ///
        /// `rgb` is a node "color" and `alias` is 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. These will be included in the node_announcement, publicly
        /// tying these addresses together and to this node. If you wish to preserve user privacy,
        /// addresses should likely contain only Tor Onion addresses.
        ///
        /// Panics if `addresses` is absurdly large (more than 100).
        ///
        /// [`get_and_clear_pending_msg_events`]: MessageSendEventsProvider::get_and_clear_pending_msg_events
        pub fn broadcast_node_announcement(&self, rgb: [u8; 3], alias: [u8; 32], mut addresses: Vec<NetAddress>) {
                if addresses.len() > 100 {
                        panic!("More than half the message size was taken up by public addresses!");
                }

                // While all existing nodes handle unsorted addresses just fine, the spec requires that
                // addresses be sorted for future compatibility.
                addresses.sort_by_key(|addr| addr.get_id());

                let features = self.message_handler.chan_handler.provided_node_features()
                        .or(self.message_handler.route_handler.provided_node_features())
                        .or(self.message_handler.onion_message_handler.provided_node_features());
                let announcement = msgs::UnsignedNodeAnnouncement {
                        features,
                        timestamp: self.last_node_announcement_serial.fetch_add(1, Ordering::AcqRel) as u32,
                        node_id: PublicKey::from_secret_key(&self.secp_ctx, &self.our_node_secret),
                        rgb, alias, addresses,
                        excess_address_data: Vec::new(),
                        excess_data: Vec::new(),
                };
                let msghash = hash_to_message!(&Sha256dHash::hash(&announcement.encode()[..])[..]);
                let node_announce_sig = sign(&self.secp_ctx, &msghash, &self.our_node_secret);

                let msg = msgs::NodeAnnouncement {
                        signature: node_announce_sig,
                        contents: announcement
                };

                log_debug!(self.logger, "Broadcasting NodeAnnouncement after passing it to our own RoutingMessageHandler.");
                let _ = self.message_handler.route_handler.handle_node_announcement(&msg);
                self.forward_broadcast_msg(&*self.peers.read().unwrap(), &wire::Message::NodeAnnouncement(msg), None);
        }
}

fn is_gossip_msg(type_id: u16) -> bool {
        match type_id {
                msgs::ChannelAnnouncement::TYPE |
                msgs::ChannelUpdate::TYPE |
                msgs::NodeAnnouncement::TYPE |
                msgs::QueryChannelRange::TYPE |
                msgs::ReplyChannelRange::TYPE |
                msgs::QueryShortChannelIds::TYPE |
                msgs::ReplyShortChannelIdsEnd::TYPE => true,
                _ => false
        }
}

#[cfg(test)]
mod tests {
        use ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor, IgnoringMessageHandler, filter_addresses};
        use ln::{msgs, wire};
        use ln::msgs::NetAddress;
        use util::events;
        use util::test_utils;

        use bitcoin::secp256k1::Secp256k1;
        use bitcoin::secp256k1::{SecretKey, PublicKey};

        use prelude::*;
        use sync::{Arc, Mutex};
        use core::sync::atomic::Ordering;

        #[derive(Clone)]
        struct FileDescriptor {
                fd: u16,
                outbound_data: Arc<Mutex<Vec<u8>>>,
        }
        impl PartialEq for FileDescriptor {
                fn eq(&self, other: &Self) -> bool {
                        self.fd == other.fd
                }
        }
        impl Eq for FileDescriptor { }
        impl core::hash::Hash for FileDescriptor {
                fn hash<H: core::hash::Hasher>(&self, hasher: &mut H) {
                        self.fd.hash(hasher)
                }
        }

        impl SocketDescriptor for FileDescriptor {
                fn send_data(&mut self, data: &[u8], _resume_read: bool) -> usize {
                        self.outbound_data.lock().unwrap().extend_from_slice(data);
                        data.len()
                }

                fn disconnect_socket(&mut self) {}
        }

        struct PeerManagerCfg {
                chan_handler: test_utils::TestChannelMessageHandler,
                routing_handler: test_utils::TestRoutingMessageHandler,
                logger: test_utils::TestLogger,
        }

        fn create_peermgr_cfgs(peer_count: usize) -> Vec<PeerManagerCfg> {
                let mut cfgs = Vec::new();
                for _ in 0..peer_count {
                        cfgs.push(
                                PeerManagerCfg{
                                        chan_handler: test_utils::TestChannelMessageHandler::new(),
                                        logger: test_utils::TestLogger::new(),
                                        routing_handler: test_utils::TestRoutingMessageHandler::new(),
                                }
                        );
                }

                cfgs
        }

        fn create_network<'a>(peer_count: usize, cfgs: &'a Vec<PeerManagerCfg>) -> Vec<PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler, &'a test_utils::TestRoutingMessageHandler, IgnoringMessageHandler, &'a test_utils::TestLogger, IgnoringMessageHandler>> {
                let mut peers = Vec::new();
                for i in 0..peer_count {
                        let node_secret = SecretKey::from_slice(&[42 + i as u8; 32]).unwrap();
                        let ephemeral_bytes = [i as u8; 32];
                        let msg_handler = MessageHandler { chan_handler: &cfgs[i].chan_handler, route_handler: &cfgs[i].routing_handler, onion_message_handler: IgnoringMessageHandler {} };
                        let peer = PeerManager::new(msg_handler, node_secret, 0, &ephemeral_bytes, &cfgs[i].logger, IgnoringMessageHandler {});
                        peers.push(peer);
                }

                peers
        }

        fn establish_connection<'a>(peer_a: &PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler, &'a test_utils::TestRoutingMessageHandler, IgnoringMessageHandler, &'a test_utils::TestLogger, IgnoringMessageHandler>, peer_b: &PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler, &'a test_utils::TestRoutingMessageHandler, IgnoringMessageHandler, &'a test_utils::TestLogger, IgnoringMessageHandler>) -> (FileDescriptor, FileDescriptor) {
                let secp_ctx = Secp256k1::new();
                let a_id = PublicKey::from_secret_key(&secp_ctx, &peer_a.our_node_secret);
                let mut fd_a = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
                let mut fd_b = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
                let initial_data = peer_b.new_outbound_connection(a_id, fd_b.clone(), None).unwrap();
                peer_a.new_inbound_connection(fd_a.clone(), None).unwrap();
                assert_eq!(peer_a.read_event(&mut fd_a, &initial_data).unwrap(), false);
                peer_a.process_events();

                let a_data = fd_a.outbound_data.lock().unwrap().split_off(0);
                assert_eq!(peer_b.read_event(&mut fd_b, &a_data).unwrap(), false);

                peer_b.process_events();
                let b_data = fd_b.outbound_data.lock().unwrap().split_off(0);
                assert_eq!(peer_a.read_event(&mut fd_a, &b_data).unwrap(), false);

                peer_a.process_events();
                let a_data = fd_a.outbound_data.lock().unwrap().split_off(0);
                assert_eq!(peer_b.read_event(&mut fd_b, &a_data).unwrap(), false);

                (fd_a.clone(), fd_b.clone())
        }

        #[test]
        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 cfgs = create_peermgr_cfgs(2);
                let chan_handler = test_utils::TestChannelMessageHandler::new();
                let mut peers = create_network(2, &cfgs);
                establish_connection(&peers[0], &peers[1]);
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);

                let secp_ctx = Secp256k1::new();
                let their_id = PublicKey::from_secret_key(&secp_ctx, &peers[1].our_node_secret);

                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 = &chan_handler;

                peers[0].process_events();
                assert_eq!(peers[0].peers.read().unwrap().len(), 0);
        }

        #[test]
        fn test_send_simple_msg() {
                // Simple test which builds a network of PeerManager, connects and brings them to NoiseState::Finished and
                // push a message from one peer to another.
                let cfgs = create_peermgr_cfgs(2);
                let a_chan_handler = test_utils::TestChannelMessageHandler::new();
                let b_chan_handler = test_utils::TestChannelMessageHandler::new();
                let mut peers = create_network(2, &cfgs);
                let (fd_a, mut fd_b) = establish_connection(&peers[0], &peers[1]);
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);

                let secp_ctx = Secp256k1::new();
                let their_id = PublicKey::from_secret_key(&secp_ctx, &peers[1].our_node_secret);

                let msg = msgs::Shutdown { channel_id: [42; 32], scriptpubkey: bitcoin::Script::new() };
                a_chan_handler.pending_events.lock().unwrap().push(events::MessageSendEvent::SendShutdown {
                        node_id: their_id, msg: msg.clone()
                });
                peers[0].message_handler.chan_handler = &a_chan_handler;

                b_chan_handler.expect_receive_msg(wire::Message::Shutdown(msg));
                peers[1].message_handler.chan_handler = &b_chan_handler;

                peers[0].process_events();

                let a_data = fd_a.outbound_data.lock().unwrap().split_off(0);
                assert_eq!(peers[1].read_event(&mut fd_b, &a_data).unwrap(), false);
        }

        #[test]
        fn test_disconnect_all_peer() {
                // Simple test which builds a network of PeerManager, connects and brings them to NoiseState::Finished and
                // then calls disconnect_all_peers
                let cfgs = create_peermgr_cfgs(2);
                let peers = create_network(2, &cfgs);
                establish_connection(&peers[0], &peers[1]);
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);

                peers[0].disconnect_all_peers();
                assert_eq!(peers[0].peers.read().unwrap().len(), 0);
        }

        #[test]
        fn test_timer_tick_occurred() {
                // Create peers, a vector of two peer managers, perform initial set up and check that peers[0] has one Peer.
                let cfgs = create_peermgr_cfgs(2);
                let peers = create_network(2, &cfgs);
                establish_connection(&peers[0], &peers[1]);
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);

                // peers[0] awaiting_pong is set to true, but the Peer is still connected
                peers[0].timer_tick_occurred();
                peers[0].process_events();
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);

                // Since timer_tick_occurred() is called again when awaiting_pong is true, all Peers are disconnected
                peers[0].timer_tick_occurred();
                peers[0].process_events();
                assert_eq!(peers[0].peers.read().unwrap().len(), 0);
        }

        #[test]
        fn test_do_attempt_write_data() {
                // Create 2 peers with custom TestRoutingMessageHandlers and connect them.
                let cfgs = create_peermgr_cfgs(2);
                cfgs[0].routing_handler.request_full_sync.store(true, Ordering::Release);
                cfgs[1].routing_handler.request_full_sync.store(true, Ordering::Release);
                let peers = create_network(2, &cfgs);

                // By calling establish_connect, we trigger do_attempt_write_data between
                // the peers. Previously this function would mistakenly enter an infinite loop
                // when there were more channel messages available than could fit into a peer's
                // buffer. This issue would now be detected by this test (because we use custom
                // RoutingMessageHandlers that intentionally return more channel messages
                // than can fit into a peer's buffer).
                let (mut fd_a, mut fd_b) = establish_connection(&peers[0], &peers[1]);

                // Make each peer to read the messages that the other peer just wrote to them. Note that
                // due to the max-message-before-ping limits this may take a few iterations to complete.
                for _ in 0..150/super::BUFFER_DRAIN_MSGS_PER_TICK + 1 {
                        peers[1].process_events();
                        let a_read_data = fd_b.outbound_data.lock().unwrap().split_off(0);
                        assert!(!a_read_data.is_empty());

                        peers[0].read_event(&mut fd_a, &a_read_data).unwrap();
                        peers[0].process_events();

                        let b_read_data = fd_a.outbound_data.lock().unwrap().split_off(0);
                        assert!(!b_read_data.is_empty());
                        peers[1].read_event(&mut fd_b, &b_read_data).unwrap();

                        peers[0].process_events();
                        assert_eq!(fd_a.outbound_data.lock().unwrap().len(), 0, "Until A receives data, it shouldn't send more messages");
                }

                // Check that each peer has received the expected number of channel updates and channel
                // announcements.
                assert_eq!(cfgs[0].routing_handler.chan_upds_recvd.load(Ordering::Acquire), 108);
                assert_eq!(cfgs[0].routing_handler.chan_anns_recvd.load(Ordering::Acquire), 54);
                assert_eq!(cfgs[1].routing_handler.chan_upds_recvd.load(Ordering::Acquire), 108);
                assert_eq!(cfgs[1].routing_handler.chan_anns_recvd.load(Ordering::Acquire), 54);
        }

        #[test]
        fn test_handshake_timeout() {
                // Tests that we time out a peer still waiting on handshake completion after a full timer
                // tick.
                let cfgs = create_peermgr_cfgs(2);
                cfgs[0].routing_handler.request_full_sync.store(true, Ordering::Release);
                cfgs[1].routing_handler.request_full_sync.store(true, Ordering::Release);
                let peers = create_network(2, &cfgs);

                let secp_ctx = Secp256k1::new();
                let a_id = PublicKey::from_secret_key(&secp_ctx, &peers[0].our_node_secret);
                let mut fd_a = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
                let mut fd_b = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
                let initial_data = peers[1].new_outbound_connection(a_id, fd_b.clone(), None).unwrap();
                peers[0].new_inbound_connection(fd_a.clone(), None).unwrap();

                // If we get a single timer tick before completion, that's fine
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);
                peers[0].timer_tick_occurred();
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);

                assert_eq!(peers[0].read_event(&mut fd_a, &initial_data).unwrap(), false);
                peers[0].process_events();
                let a_data = fd_a.outbound_data.lock().unwrap().split_off(0);
                assert_eq!(peers[1].read_event(&mut fd_b, &a_data).unwrap(), false);
                peers[1].process_events();

                // ...but if we get a second timer tick, we should disconnect the peer
                peers[0].timer_tick_occurred();
                assert_eq!(peers[0].peers.read().unwrap().len(), 0);

                let b_data = fd_b.outbound_data.lock().unwrap().split_off(0);
                assert!(peers[0].read_event(&mut fd_a, &b_data).is_err());
        }

        #[test]
        fn test_filter_addresses(){
                // Tests the filter_addresses function.

                // For (10/8)
                let ip_address = NetAddress::IPv4{addr: [10, 0, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [10, 0, 255, 201], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [10, 255, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (0/8)
                let ip_address = NetAddress::IPv4{addr: [0, 0, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [0, 0, 255, 187], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [0, 255, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (100.64/10)
                let ip_address = NetAddress::IPv4{addr: [100, 64, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [100, 78, 255, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [100, 127, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (127/8)
                let ip_address = NetAddress::IPv4{addr: [127, 0, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [127, 65, 73, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [127, 255, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (169.254/16)
                let ip_address = NetAddress::IPv4{addr: [169, 254, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [169, 254, 221, 101], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [169, 254, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (172.16/12)
                let ip_address = NetAddress::IPv4{addr: [172, 16, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [172, 27, 101, 23], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [172, 31, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (192.168/16)
                let ip_address = NetAddress::IPv4{addr: [192, 168, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [192, 168, 205, 159], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [192, 168, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (192.88.99/24)
                let ip_address = NetAddress::IPv4{addr: [192, 88, 99, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [192, 88, 99, 140], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv4{addr: [192, 88, 99, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For other IPv4 addresses
                let ip_address = NetAddress::IPv4{addr: [188, 255, 99, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), Some(ip_address.clone()));
                let ip_address = NetAddress::IPv4{addr: [123, 8, 129, 14], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), Some(ip_address.clone()));
                let ip_address = NetAddress::IPv4{addr: [2, 88, 9, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), Some(ip_address.clone()));

                // For (2000::/3)
                let ip_address = NetAddress::IPv6{addr: [32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), Some(ip_address.clone()));
                let ip_address = NetAddress::IPv6{addr: [45, 34, 209, 190, 0, 123, 55, 34, 0, 0, 3, 27, 201, 0, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), Some(ip_address.clone()));
                let ip_address = NetAddress::IPv6{addr: [63, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), Some(ip_address.clone()));

                // For other IPv6 addresses
                let ip_address = NetAddress::IPv6{addr: [24, 240, 12, 32, 0, 0, 0, 0, 20, 97, 0, 32, 121, 254, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv6{addr: [68, 23, 56, 63, 0, 0, 2, 7, 75, 109, 0, 39, 0, 0, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);
                let ip_address = NetAddress::IPv6{addr: [101, 38, 140, 230, 100, 0, 30, 98, 0, 26, 0, 0, 57, 96, 0, 0], port: 1000};
                assert_eq!(filter_addresses(Some(ip_address.clone())), None);

                // For (None)
                assert_eq!(filter_addresses(None), None);
        }
}