Merge pull request #1843 from TheBlueMatt/2022-11-fix-bp-exit-docs
[rust-lightning] / lightning / src / routing / gossip.rs
index 37bf1ea5a6f9757d1da5a29f636aa0a853f2de8e..00846a7ba794a1e3b9ba52319d1daf97641097b6 100644 (file)
@@ -16,32 +16,33 @@ use bitcoin::secp256k1;
 
 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
 use bitcoin::hashes::Hash;
-use bitcoin::blockdata::script::Builder;
 use bitcoin::blockdata::transaction::TxOut;
-use bitcoin::blockdata::opcodes;
 use bitcoin::hash_types::BlockHash;
 
-use chain;
-use chain::Access;
-use ln::features::{ChannelFeatures, NodeFeatures};
-use ln::msgs::{DecodeError, ErrorAction, Init, LightningError, RoutingMessageHandler, NetAddress, MAX_VALUE_MSAT};
-use ln::msgs::{ChannelAnnouncement, ChannelUpdate, NodeAnnouncement, GossipTimestampFilter};
-use ln::msgs::{QueryChannelRange, ReplyChannelRange, QueryShortChannelIds, ReplyShortChannelIdsEnd};
-use ln::msgs;
-use util::ser::{Readable, ReadableArgs, Writeable, Writer, MaybeReadable};
-use util::logger::{Logger, Level};
-use util::events::{Event, EventHandler, MessageSendEvent, MessageSendEventsProvider};
-use util::scid_utils::{block_from_scid, scid_from_parts, MAX_SCID_BLOCK};
-
-use io;
-use io_extras::{copy, sink};
-use prelude::*;
+use crate::chain;
+use crate::chain::Access;
+use crate::ln::chan_utils::make_funding_redeemscript;
+use crate::ln::features::{ChannelFeatures, NodeFeatures, InitFeatures};
+use crate::ln::msgs::{DecodeError, ErrorAction, Init, LightningError, RoutingMessageHandler, NetAddress, MAX_VALUE_MSAT};
+use crate::ln::msgs::{ChannelAnnouncement, ChannelUpdate, NodeAnnouncement, GossipTimestampFilter};
+use crate::ln::msgs::{QueryChannelRange, ReplyChannelRange, QueryShortChannelIds, ReplyShortChannelIdsEnd};
+use crate::ln::msgs;
+use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer, MaybeReadable};
+use crate::util::logger::{Logger, Level};
+use crate::util::events::{Event, EventHandler, MessageSendEvent, MessageSendEventsProvider};
+use crate::util::scid_utils::{block_from_scid, scid_from_parts, MAX_SCID_BLOCK};
+use crate::util::string::PrintableString;
+
+use crate::io;
+use crate::io_extras::{copy, sink};
+use crate::prelude::*;
 use alloc::collections::{BTreeMap, btree_map::Entry as BtreeEntry};
 use core::{cmp, fmt};
-use sync::{RwLock, RwLockReadGuard};
+use crate::sync::{RwLock, RwLockReadGuard};
+#[cfg(feature = "std")]
 use core::sync::atomic::{AtomicUsize, Ordering};
-use sync::Mutex;
-use core::ops::Deref;
+use crate::sync::Mutex;
+use core::ops::{Bound, Deref};
 use bitcoin::hashes::hex::ToHex;
 
 #[cfg(feature = "std")]
@@ -51,6 +52,9 @@ use std::time::{SystemTime, UNIX_EPOCH};
 /// suggestion.
 const STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS: u64 = 60 * 60 * 24 * 14;
 
+/// We stop tracking the removal of permanently failed nodes and channels one week after removal
+const REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS: u64 = 60 * 60 * 24 * 7;
+
 /// The maximum number of extra bytes which we do not understand in a gossip message before we will
 /// refuse to relay the message.
 const MAX_EXCESS_BYTES_FOR_RELAY: usize = 1024;
@@ -131,6 +135,25 @@ pub struct NetworkGraph<L: Deref> where L::Target: Logger {
        // Lock order: channels -> nodes
        channels: RwLock<BTreeMap<u64, ChannelInfo>>,
        nodes: RwLock<BTreeMap<NodeId, NodeInfo>>,
+       // Lock order: removed_channels -> removed_nodes
+       //
+       // NOTE: In the following `removed_*` maps, we use seconds since UNIX epoch to track time instead
+       // of `std::time::Instant`s for a few reasons:
+       //   * We want it to be possible to do tracking in no-std environments where we can compare
+       //     a provided current UNIX timestamp with the time at which we started tracking.
+       //   * In the future, if we decide to persist these maps, they will already be serializable.
+       //   * Although we lose out on the platform's monotonic clock, the system clock in a std
+       //     environment should be practical over the time period we are considering (on the order of a
+       //     week).
+       //
+       /// Keeps track of short channel IDs for channels we have explicitly removed due to permanent
+       /// failure so that we don't resync them from gossip. Each SCID is mapped to the time (in seconds)
+       /// it was removed so that once some time passes, we can potentially resync it from gossip again.
+       removed_channels: Mutex<HashMap<u64, Option<u64>>>,
+       /// Keeps track of `NodeId`s we have explicitly removed due to permanent failure so that we don't
+       /// resync them from gossip. Each `NodeId` is mapped to the time (in seconds) it was removed so
+       /// that once some time passes, we can potentially resync it from gossip again.
+       removed_nodes: Mutex<HashMap<NodeId, Option<u64>>>,
 }
 
 /// A read-only view of [`NetworkGraph`].
@@ -143,7 +166,7 @@ pub struct ReadOnlyNetworkGraph<'a> {
 /// return packet by a node along the route. See [BOLT #4] for details.
 ///
 /// [BOLT #4]: https://github.com/lightning/bolts/blob/master/04-onion-routing.md
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum NetworkUpdate {
        /// An error indicating a `channel_update` messages should be applied via
        /// [`NetworkGraph::update_channel`].
@@ -161,7 +184,7 @@ pub enum NetworkUpdate {
                is_permanent: bool,
        },
        /// An error indicating that a node failed to route a payment, which should be applied via
-       /// [`NetworkGraph::node_failed`].
+       /// [`NetworkGraph::node_failed_permanent`] if permanent.
        NodeFailure {
                /// The node id of the failed node.
                node_id: PublicKey,
@@ -198,6 +221,7 @@ where C::Target: chain::Access, L::Target: Logger
 {
        network_graph: G,
        chain_access: Option<C>,
+       #[cfg(feature = "std")]
        full_syncs_requested: AtomicUsize,
        pending_events: Mutex<Vec<MessageSendEvent>>,
        logger: L,
@@ -214,6 +238,7 @@ where C::Target: chain::Access, L::Target: Logger
        pub fn new(network_graph: G, chain_access: Option<C>, logger: L) -> Self {
                P2PGossipSync {
                        network_graph,
+                       #[cfg(feature = "std")]
                        full_syncs_requested: AtomicUsize::new(0),
                        chain_access,
                        pending_events: Mutex::new(vec![]),
@@ -236,6 +261,7 @@ where C::Target: chain::Access, L::Target: Logger
                &self.network_graph
        }
 
+       #[cfg(feature = "std")]
        /// Returns true when a full routing table sync should be performed with a peer.
        fn should_request_full_sync(&self, _node_id: &PublicKey) -> bool {
                //TODO: Determine whether to request a full sync based on the network map.
@@ -267,9 +293,11 @@ impl<L: Deref> EventHandler for NetworkGraph<L> where L::Target: Logger {
                                                self.channel_failed(short_channel_id, is_permanent);
                                        },
                                        NetworkUpdate::NodeFailure { ref node_id, is_permanent } => {
-                                               let action = if is_permanent { "Removing" } else { "Disabling" };
-                                               log_debug!(self.logger, "{} node graph entry for {} due to a payment failure.", action, node_id);
-                                               self.node_failed(node_id, is_permanent);
+                                               if is_permanent {
+                                                       log_debug!(self.logger,
+                                                               "Removed node graph entry for {} due to a payment failure.", log_pubkey!(node_id));
+                                                       self.node_failed_permanent(node_id);
+                                               };
                                        },
                                }
                        }
@@ -318,56 +346,43 @@ where C::Target: chain::Access, L::Target: Logger
                Ok(msg.contents.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY)
        }
 
-       fn get_next_channel_announcements(&self, starting_point: u64, batch_amount: u8) -> Vec<(ChannelAnnouncement, Option<ChannelUpdate>, Option<ChannelUpdate>)> {
-               let mut result = Vec::with_capacity(batch_amount as usize);
+       fn get_next_channel_announcement(&self, starting_point: u64) -> Option<(ChannelAnnouncement, Option<ChannelUpdate>, Option<ChannelUpdate>)> {
                let channels = self.network_graph.channels.read().unwrap();
-               let mut iter = channels.range(starting_point..);
-               while result.len() < batch_amount as usize {
-                       if let Some((_, ref chan)) = iter.next() {
-                               if chan.announcement_message.is_some() {
-                                       let chan_announcement = chan.announcement_message.clone().unwrap();
-                                       let mut one_to_two_announcement: Option<msgs::ChannelUpdate> = None;
-                                       let mut two_to_one_announcement: Option<msgs::ChannelUpdate> = None;
-                                       if let Some(one_to_two) = chan.one_to_two.as_ref() {
-                                               one_to_two_announcement = one_to_two.last_update_message.clone();
-                                       }
-                                       if let Some(two_to_one) = chan.two_to_one.as_ref() {
-                                               two_to_one_announcement = two_to_one.last_update_message.clone();
-                                       }
-                                       result.push((chan_announcement, one_to_two_announcement, two_to_one_announcement));
-                               } else {
-                                       // TODO: We may end up sending un-announced channel_updates if we are sending
-                                       // initial sync data while receiving announce/updates for this channel.
+               for (_, ref chan) in channels.range(starting_point..) {
+                       if chan.announcement_message.is_some() {
+                               let chan_announcement = chan.announcement_message.clone().unwrap();
+                               let mut one_to_two_announcement: Option<msgs::ChannelUpdate> = None;
+                               let mut two_to_one_announcement: Option<msgs::ChannelUpdate> = None;
+                               if let Some(one_to_two) = chan.one_to_two.as_ref() {
+                                       one_to_two_announcement = one_to_two.last_update_message.clone();
                                }
+                               if let Some(two_to_one) = chan.two_to_one.as_ref() {
+                                       two_to_one_announcement = two_to_one.last_update_message.clone();
+                               }
+                               return Some((chan_announcement, one_to_two_announcement, two_to_one_announcement));
                        } else {
-                               return result;
+                               // TODO: We may end up sending un-announced channel_updates if we are sending
+                               // initial sync data while receiving announce/updates for this channel.
                        }
                }
-               result
+               None
        }
 
-       fn get_next_node_announcements(&self, starting_point: Option<&PublicKey>, batch_amount: u8) -> Vec<NodeAnnouncement> {
-               let mut result = Vec::with_capacity(batch_amount as usize);
+       fn get_next_node_announcement(&self, starting_point: Option<&PublicKey>) -> Option<NodeAnnouncement> {
                let nodes = self.network_graph.nodes.read().unwrap();
-               let mut iter = if let Some(pubkey) = starting_point {
-                               let mut iter = nodes.range(NodeId::from_pubkey(pubkey)..);
-                               iter.next();
-                               iter
+               let iter = if let Some(pubkey) = starting_point {
+                               nodes.range((Bound::Excluded(NodeId::from_pubkey(pubkey)), Bound::Unbounded))
                        } else {
-                               nodes.range::<NodeId, _>(..)
+                               nodes.range(..)
                        };
-               while result.len() < batch_amount as usize {
-                       if let Some((_, ref node)) = iter.next() {
-                               if let Some(node_info) = node.announcement_info.as_ref() {
-                                       if node_info.announcement_message.is_some() {
-                                               result.push(node_info.announcement_message.clone().unwrap());
-                                       }
+               for (_, ref node) in iter {
+                       if let Some(node_info) = node.announcement_info.as_ref() {
+                               if let Some(msg) = node_info.announcement_message.clone() {
+                                       return Some(msg);
                                }
-                       } else {
-                               return result;
                        }
                }
-               result
+               None
        }
 
        /// Initiates a stateless sync of routing gossip information with a peer
@@ -379,10 +394,12 @@ where C::Target: chain::Access, L::Target: Logger
        /// to request gossip messages for each channel. The sync is considered complete
        /// when the final reply_scids_end message is received, though we are not
        /// tracking this directly.
-       fn peer_connected(&self, their_node_id: &PublicKey, init_msg: &Init) {
+       fn peer_connected(&self, their_node_id: &PublicKey, init_msg: &Init) -> Result<(), ()> {
                // We will only perform a sync with peers that support gossip_queries.
                if !init_msg.features.supports_gossip_queries() {
-                       return ();
+                       // Don't disconnect peers for not supporting gossip queries. We may wish to have
+                       // channels with peers even without being able to exchange gossip.
+                       return Ok(());
                }
 
                // The lightning network's gossip sync system is completely broken in numerous ways.
@@ -435,13 +452,12 @@ where C::Target: chain::Access, L::Target: Logger
                // `gossip_timestamp_filter`, with the filter time set either two weeks ago or an hour ago.
                //
                // For no-std builds, we bury our head in the sand and do a full sync on each connection.
-               let should_request_full_sync = self.should_request_full_sync(&their_node_id);
                #[allow(unused_mut, unused_assignments)]
                let mut gossip_start_time = 0;
                #[cfg(feature = "std")]
                {
                        gossip_start_time = SystemTime::now().duration_since(UNIX_EPOCH).expect("Time must be > 1970").as_secs();
-                       if should_request_full_sync {
+                       if self.should_request_full_sync(&their_node_id) {
                                gossip_start_time -= 60 * 60 * 24 * 7 * 2; // 2 weeks ago
                        } else {
                                gossip_start_time -= 60 * 60; // an hour ago
@@ -457,6 +473,7 @@ where C::Target: chain::Access, L::Target: Logger
                                timestamp_range: u32::max_value(),
                        },
                });
+               Ok(())
        }
 
        fn handle_reply_channel_range(&self, _their_node_id: &PublicKey, _msg: ReplyChannelRange) -> Result<(), LightningError> {
@@ -584,6 +601,18 @@ where C::Target: chain::Access, L::Target: Logger
                        action: ErrorAction::IgnoreError,
                })
        }
+
+       fn provided_node_features(&self) -> NodeFeatures {
+               let mut features = NodeFeatures::empty();
+               features.set_gossip_queries_optional();
+               features
+       }
+
+       fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
+               let mut features = InitFeatures::empty();
+               features.set_gossip_queries_optional();
+               features
+       }
 }
 
 impl<G: Deref<Target=NetworkGraph<L>>, C: Deref, L: Deref> MessageSendEventsProvider for P2PGossipSync<G, C, L>
@@ -599,7 +628,7 @@ where
        }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 /// Details about one direction of a channel as received within a [`ChannelUpdate`].
 pub struct ChannelUpdateInfo {
        /// When the last update to the channel direction was issued.
@@ -630,7 +659,7 @@ impl fmt::Display for ChannelUpdateInfo {
 }
 
 impl Writeable for ChannelUpdateInfo {
-       fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+       fn write<W: crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                write_tlv_fields!(writer, {
                        (0, self.last_update, required),
                        (2, self.enabled, required),
@@ -682,7 +711,7 @@ impl Readable for ChannelUpdateInfo {
        }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 /// Details about a channel (both directions).
 /// Received within a channel announcement.
 pub struct ChannelInfo {
@@ -722,7 +751,7 @@ impl ChannelInfo {
                                return None;
                        }
                };
-               Some((DirectedChannelInfo::new(self, direction), source))
+               direction.map(|dir| (DirectedChannelInfo::new(self, dir), source))
        }
 
        /// Returns a [`DirectedChannelInfo`] for the channel directed from the given `source` to a
@@ -737,7 +766,7 @@ impl ChannelInfo {
                                return None;
                        }
                };
-               Some((DirectedChannelInfo::new(self, direction), target))
+               direction.map(|dir| (DirectedChannelInfo::new(self, dir), target))
        }
 
        /// Returns a [`ChannelUpdateInfo`] based on the direction implied by the channel_flag.
@@ -760,7 +789,7 @@ impl fmt::Display for ChannelInfo {
 }
 
 impl Writeable for ChannelInfo {
-       fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+       fn write<W: crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                write_tlv_fields!(writer, {
                        (0, self.features, required),
                        (1, self.announcement_received_time, (default_value, 0)),
@@ -784,7 +813,7 @@ struct ChannelUpdateInfoDeserWrapper(Option<ChannelUpdateInfo>);
 
 impl MaybeReadable for ChannelUpdateInfoDeserWrapper {
        fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
-               match ::util::ser::Readable::read(reader) {
+               match crate::util::ser::Readable::read(reader) {
                        Ok(channel_update_option) => Ok(Some(Self(channel_update_option))),
                        Err(DecodeError::ShortRead) => Ok(None),
                        Err(DecodeError::InvalidValue) => Ok(None),
@@ -832,29 +861,23 @@ impl Readable for ChannelInfo {
 #[derive(Clone)]
 pub struct DirectedChannelInfo<'a> {
        channel: &'a ChannelInfo,
-       direction: Option<&'a ChannelUpdateInfo>,
+       direction: &'a ChannelUpdateInfo,
        htlc_maximum_msat: u64,
        effective_capacity: EffectiveCapacity,
 }
 
 impl<'a> DirectedChannelInfo<'a> {
        #[inline]
-       fn new(channel: &'a ChannelInfo, direction: Option<&'a ChannelUpdateInfo>) -> Self {
-               let htlc_maximum_msat = direction.map(|direction| direction.htlc_maximum_msat);
+       fn new(channel: &'a ChannelInfo, direction: &'a ChannelUpdateInfo) -> Self {
+               let mut htlc_maximum_msat = direction.htlc_maximum_msat;
                let capacity_msat = channel.capacity_sats.map(|capacity_sats| capacity_sats * 1000);
 
-               let (htlc_maximum_msat, effective_capacity) = match (htlc_maximum_msat, capacity_msat) {
-                       (Some(amount_msat), Some(capacity_msat)) => {
-                               let htlc_maximum_msat = cmp::min(amount_msat, capacity_msat);
-                               (htlc_maximum_msat, EffectiveCapacity::Total { capacity_msat, htlc_maximum_msat: Some(htlc_maximum_msat) })
-                       },
-                       (Some(amount_msat), None) => {
-                               (amount_msat, EffectiveCapacity::MaximumHTLC { amount_msat })
-                       },
-                       (None, Some(capacity_msat)) => {
-                               (capacity_msat, EffectiveCapacity::Total { capacity_msat, htlc_maximum_msat: None })
+               let effective_capacity = match capacity_msat {
+                       Some(capacity_msat) => {
+                               htlc_maximum_msat = cmp::min(htlc_maximum_msat, capacity_msat);
+                               EffectiveCapacity::Total { capacity_msat, htlc_maximum_msat: htlc_maximum_msat }
                        },
-                       (None, None) => (EffectiveCapacity::Unknown.as_msat(), EffectiveCapacity::Unknown),
+                       None => EffectiveCapacity::MaximumHTLC { amount_msat: htlc_maximum_msat },
                };
 
                Self {
@@ -863,12 +886,11 @@ impl<'a> DirectedChannelInfo<'a> {
        }
 
        /// Returns information for the channel.
+       #[inline]
        pub fn channel(&self) -> &'a ChannelInfo { self.channel }
 
-       /// Returns information for the direction.
-       pub fn direction(&self) -> Option<&'a ChannelUpdateInfo> { self.direction }
-
        /// Returns the maximum HTLC amount allowed over the channel in the direction.
+       #[inline]
        pub fn htlc_maximum_msat(&self) -> u64 {
                self.htlc_maximum_msat
        }
@@ -882,13 +904,9 @@ impl<'a> DirectedChannelInfo<'a> {
                self.effective_capacity
        }
 
-       /// Returns `Some` if [`ChannelUpdateInfo`] is available in the direction.
-       pub(super) fn with_update(self) -> Option<DirectedChannelInfoWithUpdate<'a>> {
-               match self.direction {
-                       Some(_) => Some(DirectedChannelInfoWithUpdate { inner: self }),
-                       None => None,
-               }
-       }
+       /// Returns information for the direction.
+       #[inline]
+       pub(super) fn direction(&self) -> &'a ChannelUpdateInfo { self.direction }
 }
 
 impl<'a> fmt::Debug for DirectedChannelInfo<'a> {
@@ -899,37 +917,11 @@ impl<'a> fmt::Debug for DirectedChannelInfo<'a> {
        }
 }
 
-/// A [`DirectedChannelInfo`] with [`ChannelUpdateInfo`] available in its direction.
-#[derive(Clone)]
-pub(super) struct DirectedChannelInfoWithUpdate<'a> {
-       inner: DirectedChannelInfo<'a>,
-}
-
-impl<'a> DirectedChannelInfoWithUpdate<'a> {
-       /// Returns information for the channel.
-       #[inline]
-       pub(super) fn channel(&self) -> &'a ChannelInfo { &self.inner.channel }
-
-       /// Returns information for the direction.
-       #[inline]
-       pub(super) fn direction(&self) -> &'a ChannelUpdateInfo { self.inner.direction.unwrap() }
-
-       /// Returns the [`EffectiveCapacity`] of the channel in the direction.
-       #[inline]
-       pub(super) fn effective_capacity(&self) -> EffectiveCapacity { self.inner.effective_capacity() }
-}
-
-impl<'a> fmt::Debug for DirectedChannelInfoWithUpdate<'a> {
-       fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-               self.inner.fmt(f)
-       }
-}
-
 /// The effective capacity of a channel for routing purposes.
 ///
 /// While this may be smaller than the actual channel capacity, amounts greater than
 /// [`Self::as_msat`] should not be routed through the channel.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 pub enum EffectiveCapacity {
        /// The available liquidity in the channel known from being a channel counterparty, and thus a
        /// direct hop.
@@ -948,7 +940,7 @@ pub enum EffectiveCapacity {
                /// The funding amount denominated in millisatoshi.
                capacity_msat: u64,
                /// The maximum HTLC amount denominated in millisatoshi.
-               htlc_maximum_msat: Option<u64>
+               htlc_maximum_msat: u64
        },
        /// A capacity sufficient to route any payment, typically used for private channels provided by
        /// an invoice.
@@ -990,7 +982,7 @@ impl_writeable_tlv_based!(RoutingFees, {
        (2, proportional_millionths, required)
 });
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 /// Information received in the latest node_announcement from this node.
 pub struct NodeAnnouncementInfo {
        /// Protocol features the node announced support for
@@ -1026,28 +1018,22 @@ impl_writeable_tlv_based!(NodeAnnouncementInfo, {
 ///
 /// Since node aliases are provided by third parties, they are a potential avenue for injection
 /// attacks. Care must be taken when processing.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct NodeAlias(pub [u8; 32]);
 
 impl fmt::Display for NodeAlias {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-               let control_symbol = core::char::REPLACEMENT_CHARACTER;
                let first_null = self.0.iter().position(|b| *b == 0).unwrap_or(self.0.len());
                let bytes = self.0.split_at(first_null).0;
                match core::str::from_utf8(bytes) {
-                       Ok(alias) => {
-                               for c in alias.chars() {
-                                       let mut bytes = [0u8; 4];
-                                       let c = if !c.is_control() { c } else { control_symbol };
-                                       f.write_str(c.encode_utf8(&mut bytes))?;
-                               }
-                       },
+                       Ok(alias) => PrintableString(alias).fmt(f)?,
                        Err(_) => {
+                               use core::fmt::Write;
                                for c in bytes.iter().map(|b| *b as char) {
                                        // Display printable ASCII characters
-                                       let mut bytes = [0u8; 4];
+                                       let control_symbol = core::char::REPLACEMENT_CHARACTER;
                                        let c = if c >= '\x20' && c <= '\x7e' { c } else { control_symbol };
-                                       f.write_str(c.encode_utf8(&mut bytes))?;
+                                       f.write_char(c)?;
                                }
                        },
                };
@@ -1067,7 +1053,7 @@ impl Readable for NodeAlias {
        }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 /// Details about a node in the network, known from the network announcement.
 pub struct NodeInfo {
        /// All valid channels a node has announced
@@ -1091,7 +1077,7 @@ impl fmt::Display for NodeInfo {
 }
 
 impl Writeable for NodeInfo {
-       fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+       fn write<W: crate::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                write_tlv_fields!(writer, {
                        (0, self.lowest_inbound_channel_fees, option),
                        (2, self.announcement_info, option),
@@ -1109,7 +1095,7 @@ struct NodeAnnouncementInfoDeserWrapper(NodeAnnouncementInfo);
 
 impl MaybeReadable for NodeAnnouncementInfoDeserWrapper {
        fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
-               match ::util::ser::Readable::read(reader) {
+               match crate::util::ser::Readable::read(reader) {
                        Ok(node_announcement_info) => return Ok(Some(Self(node_announcement_info))),
                        Err(_) => {
                                copy(reader, &mut sink()).unwrap();
@@ -1200,6 +1186,8 @@ impl<L: Deref> ReadableArgs<L> for NetworkGraph<L> where L::Target: Logger {
                        channels: RwLock::new(channels),
                        nodes: RwLock::new(nodes),
                        last_rapid_gossip_sync_timestamp: Mutex::new(last_rapid_gossip_sync_timestamp),
+                       removed_nodes: Mutex::new(HashMap::new()),
+                       removed_channels: Mutex::new(HashMap::new()),
                })
        }
 }
@@ -1218,6 +1206,7 @@ impl<L: Deref> fmt::Display for NetworkGraph<L> where L::Target: Logger {
        }
 }
 
+impl<L: Deref> Eq for NetworkGraph<L> where L::Target: Logger {}
 impl<L: Deref> PartialEq for NetworkGraph<L> where L::Target: Logger {
        fn eq(&self, other: &Self) -> bool {
                self.genesis_hash == other.genesis_hash &&
@@ -1236,6 +1225,8 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                        channels: RwLock::new(BTreeMap::new()),
                        nodes: RwLock::new(BTreeMap::new()),
                        last_rapid_gossip_sync_timestamp: Mutex::new(None),
+                       removed_channels: Mutex::new(HashMap::new()),
+                       removed_nodes: Mutex::new(HashMap::new()),
                }
        }
 
@@ -1299,7 +1290,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                                        // updates to ensure you always have the latest one, only vaguely suggesting
                                        // that it be at least the current time.
                                        if node_info.last_update  > msg.timestamp {
-                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreAndLog(Level::Gossip)});
+                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreDuplicateGossip});
                                        } else if node_info.last_update  == msg.timestamp {
                                                return Err(LightningError{err: "Update had the same timestamp as last processed update".to_owned(), action: ErrorAction::IgnoreDuplicateGossip});
                                        }
@@ -1447,6 +1438,54 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                        return Err(LightningError{err: "Channel announcement node had a channel with itself".to_owned(), action: ErrorAction::IgnoreError});
                }
 
+               let node_one = NodeId::from_pubkey(&msg.node_id_1);
+               let node_two = NodeId::from_pubkey(&msg.node_id_2);
+
+               {
+                       let channels = self.channels.read().unwrap();
+
+                       if let Some(chan) = channels.get(&msg.short_channel_id) {
+                               if chan.capacity_sats.is_some() {
+                                       // If we'd previously looked up the channel on-chain and checked the script
+                                       // against what appears on-chain, ignore the duplicate announcement.
+                                       //
+                                       // Because a reorg could replace one channel with another at the same SCID, if
+                                       // the channel appears to be different, we re-validate. This doesn't expose us
+                                       // to any more DoS risk than not, as a peer can always flood us with
+                                       // randomly-generated SCID values anyway.
+                                       //
+                                       // We use the Node IDs rather than the bitcoin_keys to check for "equivalence"
+                                       // as we didn't (necessarily) store the bitcoin keys, and we only really care
+                                       // if the peers on the channel changed anyway.
+                                       if node_one == chan.node_one && node_two == chan.node_two {
+                                               return Err(LightningError {
+                                                       err: "Already have chain-validated channel".to_owned(),
+                                                       action: ErrorAction::IgnoreDuplicateGossip
+                                               });
+                                       }
+                               } else if chain_access.is_none() {
+                                       // Similarly, if we can't check the chain right now anyway, ignore the
+                                       // duplicate announcement without bothering to take the channels write lock.
+                                       return Err(LightningError {
+                                               err: "Already have non-chain-validated channel".to_owned(),
+                                               action: ErrorAction::IgnoreDuplicateGossip
+                                       });
+                               }
+                       }
+               }
+
+               {
+                       let removed_channels = self.removed_channels.lock().unwrap();
+                       let removed_nodes = self.removed_nodes.lock().unwrap();
+                       if removed_channels.contains_key(&msg.short_channel_id) ||
+                               removed_nodes.contains_key(&node_one) ||
+                               removed_nodes.contains_key(&node_two) {
+                               return Err(LightningError{
+                                       err: format!("Channel with SCID {} or one of its nodes was removed from our network graph recently", &msg.short_channel_id),
+                                       action: ErrorAction::IgnoreAndLog(Level::Gossip)});
+                       }
+               }
+
                let utxo_value = match &chain_access {
                        &None => {
                                // Tentatively accept, potentially exposing us to DoS attacks
@@ -1455,13 +1494,10 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                        &Some(ref chain_access) => {
                                match chain_access.get_utxo(&msg.chain_hash, msg.short_channel_id) {
                                        Ok(TxOut { value, script_pubkey }) => {
-                                               let expected_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
-                                                                                   .push_slice(&msg.bitcoin_key_1.serialize())
-                                                                                   .push_slice(&msg.bitcoin_key_2.serialize())
-                                                                                   .push_opcode(opcodes::all::OP_PUSHNUM_2)
-                                                                                   .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
+                                               let expected_script =
+                                                       make_funding_redeemscript(&msg.bitcoin_key_1, &msg.bitcoin_key_2).to_v0_p2wsh();
                                                if script_pubkey != expected_script {
-                                                       return Err(LightningError{err: format!("Channel announcement key ({}) didn't match on-chain script ({})", script_pubkey.to_hex(), expected_script.to_hex()), action: ErrorAction::IgnoreError});
+                                                       return Err(LightningError{err: format!("Channel announcement key ({}) didn't match on-chain script ({})", expected_script.to_hex(), script_pubkey.to_hex()), action: ErrorAction::IgnoreError});
                                                }
                                                //TODO: Check if value is worth storing, use it to inform routing, and compare it
                                                //to the new HTLC max field in channel_update
@@ -1486,9 +1522,9 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
 
                let chan_info = ChannelInfo {
                        features: msg.features.clone(),
-                       node_one: NodeId::from_pubkey(&msg.node_id_1),
+                       node_one,
                        one_to_two: None,
-                       node_two: NodeId::from_pubkey(&msg.node_id_2),
+                       node_two,
                        two_to_one: None,
                        capacity_sats: utxo_value,
                        announcement_message: if msg.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY
@@ -1504,10 +1540,16 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
        /// May cause the removal of nodes too, if this was their last channel.
        /// If not permanent, makes channels unavailable for routing.
        pub fn channel_failed(&self, short_channel_id: u64, is_permanent: bool) {
+               #[cfg(feature = "std")]
+               let current_time_unix = Some(SystemTime::now().duration_since(UNIX_EPOCH).expect("Time must be > 1970").as_secs());
+               #[cfg(not(feature = "std"))]
+               let current_time_unix = None;
+
                let mut channels = self.channels.write().unwrap();
                if is_permanent {
                        if let Some(chan) = channels.remove(&short_channel_id) {
                                let mut nodes = self.nodes.write().unwrap();
+                               self.removed_channels.lock().unwrap().insert(short_channel_id, current_time_unix);
                                Self::remove_channel_in_nodes(&mut nodes, &chan, short_channel_id);
                        }
                } else {
@@ -1522,12 +1564,36 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                }
        }
 
-       /// Marks a node in the graph as failed.
-       pub fn node_failed(&self, _node_id: &PublicKey, is_permanent: bool) {
-               if is_permanent {
-                       // TODO: Wholly remove the node
-               } else {
-                       // TODO: downgrade the node
+       /// Marks a node in the graph as permanently failed, effectively removing it and its channels
+       /// from local storage.
+       pub fn node_failed_permanent(&self, node_id: &PublicKey) {
+               #[cfg(feature = "std")]
+               let current_time_unix = Some(SystemTime::now().duration_since(UNIX_EPOCH).expect("Time must be > 1970").as_secs());
+               #[cfg(not(feature = "std"))]
+               let current_time_unix = None;
+
+               let node_id = NodeId::from_pubkey(node_id);
+               let mut channels = self.channels.write().unwrap();
+               let mut nodes = self.nodes.write().unwrap();
+               let mut removed_channels = self.removed_channels.lock().unwrap();
+               let mut removed_nodes = self.removed_nodes.lock().unwrap();
+
+               if let Some(node) = nodes.remove(&node_id) {
+                       for scid in node.channels.iter() {
+                               if let Some(chan_info) = channels.remove(scid) {
+                                       let other_node_id = if node_id == chan_info.node_one { chan_info.node_two } else { chan_info.node_one };
+                                       if let BtreeEntry::Occupied(mut other_node_entry) = nodes.entry(other_node_id) {
+                                               other_node_entry.get_mut().channels.retain(|chan_id| {
+                                                       *scid != *chan_id
+                                               });
+                                               if other_node_entry.get().channels.is_empty() {
+                                                       other_node_entry.remove_entry();
+                                               }
+                                       }
+                                       removed_channels.insert(*scid, current_time_unix);
+                               }
+                       }
+                       removed_nodes.insert(node_id, current_time_unix);
                }
        }
 
@@ -1543,11 +1609,14 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
        /// Note that for users of the `lightning-background-processor` crate this method may be
        /// automatically called regularly for you.
        ///
+       /// This method will also cause us to stop tracking removed nodes and channels if they have been
+       /// in the map for a while so that these can be resynced from gossip in the future.
+       ///
        /// This method is only available with the `std` feature. See
-       /// [`NetworkGraph::remove_stale_channels_with_time`] for `no-std` use.
-       pub fn remove_stale_channels(&self) {
+       /// [`NetworkGraph::remove_stale_channels_and_tracking_with_time`] for `no-std` use.
+       pub fn remove_stale_channels_and_tracking(&self) {
                let time = SystemTime::now().duration_since(UNIX_EPOCH).expect("Time must be > 1970").as_secs();
-               self.remove_stale_channels_with_time(time);
+               self.remove_stale_channels_and_tracking_with_time(time);
        }
 
        /// Removes information about channels that we haven't heard any updates about in some time.
@@ -1558,9 +1627,12 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
        /// updates every two weeks, the non-normative section of BOLT 7 currently suggests that
        /// pruning occur for updates which are at least two weeks old, which we implement here.
        ///
+       /// This method will also cause us to stop tracking removed nodes and channels if they have been
+       /// in the map for a while so that these can be resynced from gossip in the future.
+       ///
        /// This function takes the current unix time as an argument. For users with the `std` feature
-       /// enabled, [`NetworkGraph::remove_stale_channels`] may be preferable.
-       pub fn remove_stale_channels_with_time(&self, current_time_unix: u64) {
+       /// enabled, [`NetworkGraph::remove_stale_channels_and_tracking`] may be preferable.
+       pub fn remove_stale_channels_and_tracking_with_time(&self, current_time_unix: u64) {
                let mut channels = self.channels.write().unwrap();
                // Time out if we haven't received an update in at least 14 days.
                if current_time_unix > u32::max_value() as u64 { return; } // Remove by 2106
@@ -1576,7 +1648,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                        if info.two_to_one.is_some() && info.two_to_one.as_ref().unwrap().last_update < min_time_unix {
                                info.two_to_one = None;
                        }
-                       if info.one_to_two.is_none() && info.two_to_one.is_none() {
+                       if info.one_to_two.is_none() || info.two_to_one.is_none() {
                                // We check the announcement_received_time here to ensure we don't drop
                                // announcements that we just received and are just waiting for our peer to send a
                                // channel_update for.
@@ -1590,8 +1662,29 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                        for scid in scids_to_remove {
                                let info = channels.remove(&scid).expect("We just accessed this scid, it should be present");
                                Self::remove_channel_in_nodes(&mut nodes, &info, scid);
+                               self.removed_channels.lock().unwrap().insert(scid, Some(current_time_unix));
                        }
                }
+
+               let should_keep_tracking = |time: &mut Option<u64>| {
+                       if let Some(time) = time {
+                               current_time_unix.saturating_sub(*time) < REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS
+                       } else {
+                               // NOTE: In the case of no-std, we won't have access to the current UNIX time at the time of removal,
+                               // so we'll just set the removal time here to the current UNIX time on the very next invocation
+                               // of this function.
+                               #[cfg(feature = "no-std")]
+                               {
+                                       let mut tracked_time = Some(current_time_unix);
+                                       core::mem::swap(time, &mut tracked_time);
+                                       return true;
+                               }
+                               #[allow(unreachable_code)]
+                               false
+                       }};
+
+               self.removed_channels.lock().unwrap().retain(|_, time| should_keep_tracking(time));
+               self.removed_nodes.lock().unwrap().retain(|_, time| should_keep_tracking(time));
        }
 
        /// For an already known (from announcement) channel, update info about one of the directions
@@ -1664,7 +1757,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
                                                        // pruning based on the timestamp field being more than two weeks old,
                                                        // but only in the non-normative section.
                                                        if existing_chan_info.last_update > msg.timestamp {
-                                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreAndLog(Level::Gossip)});
+                                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreDuplicateGossip});
                                                        } else if existing_chan_info.last_update == msg.timestamp {
                                                                return Err(LightningError{err: "Update had same timestamp as last processed update".to_owned(), action: ErrorAction::IgnoreDuplicateGossip});
                                                        }
@@ -1796,6 +1889,12 @@ impl ReadOnlyNetworkGraph<'_> {
                self.channels.get(&short_channel_id)
        }
 
+       #[cfg(c_bindings)] // Non-bindings users should use `channels`
+       /// Returns the list of channels in the graph
+       pub fn list_channels(&self) -> Vec<u64> {
+               self.channels.keys().map(|c| *c).collect()
+       }
+
        /// Returns all known nodes' public keys along with announced node info.
        ///
        /// (C-not exported) because we have no mapping for `BTreeMap`s
@@ -1808,6 +1907,12 @@ impl ReadOnlyNetworkGraph<'_> {
                self.nodes.get(node_id)
        }
 
+       #[cfg(c_bindings)] // Non-bindings users should use `nodes`
+       /// Returns the list of nodes in the graph
+       pub fn list_nodes(&self) -> Vec<NodeId> {
+               self.nodes.keys().map(|n| *n).collect()
+       }
+
        /// Get network addresses by node id.
        /// Returns None if the requested node is completely unknown,
        /// or if node announcement for the node was never received.
@@ -1823,37 +1928,39 @@ impl ReadOnlyNetworkGraph<'_> {
 
 #[cfg(test)]
 mod tests {
-       use chain;
-       use ln::PaymentHash;
-       use ln::features::{ChannelFeatures, InitFeatures, NodeFeatures};
-       use routing::gossip::{P2PGossipSync, NetworkGraph, NetworkUpdate, NodeAlias, MAX_EXCESS_BYTES_FOR_RELAY, NodeId, RoutingFees, ChannelUpdateInfo, ChannelInfo, NodeAnnouncementInfo, NodeInfo};
-       use ln::msgs::{Init, RoutingMessageHandler, UnsignedNodeAnnouncement, NodeAnnouncement,
+       use crate::chain;
+       use crate::ln::channelmanager;
+       use crate::ln::chan_utils::make_funding_redeemscript;
+       use crate::ln::PaymentHash;
+       use crate::ln::features::InitFeatures;
+       use crate::routing::gossip::{P2PGossipSync, NetworkGraph, NetworkUpdate, NodeAlias, MAX_EXCESS_BYTES_FOR_RELAY, NodeId, RoutingFees, ChannelUpdateInfo, ChannelInfo, NodeAnnouncementInfo, NodeInfo};
+       use crate::ln::msgs::{RoutingMessageHandler, UnsignedNodeAnnouncement, NodeAnnouncement,
                UnsignedChannelAnnouncement, ChannelAnnouncement, UnsignedChannelUpdate, ChannelUpdate,
                ReplyChannelRange, QueryChannelRange, QueryShortChannelIds, MAX_VALUE_MSAT};
-       use util::test_utils;
-       use util::ser::{ReadableArgs, Writeable};
-       use util::events::{Event, EventHandler, MessageSendEvent, MessageSendEventsProvider};
-       use util::scid_utils::scid_from_parts;
+       use crate::util::test_utils;
+       use crate::util::ser::{ReadableArgs, Writeable};
+       use crate::util::events::{Event, EventHandler, MessageSendEvent, MessageSendEventsProvider};
+       use crate::util::scid_utils::scid_from_parts;
 
+       use crate::routing::gossip::REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS;
        use super::STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS;
 
        use bitcoin::hashes::sha256d::Hash as Sha256dHash;
        use bitcoin::hashes::Hash;
        use bitcoin::network::constants::Network;
        use bitcoin::blockdata::constants::genesis_block;
-       use bitcoin::blockdata::script::{Builder, Script};
+       use bitcoin::blockdata::script::Script;
        use bitcoin::blockdata::transaction::TxOut;
-       use bitcoin::blockdata::opcodes;
 
        use hex;
 
        use bitcoin::secp256k1::{PublicKey, SecretKey};
        use bitcoin::secp256k1::{All, Secp256k1};
 
-       use io;
+       use crate::io;
        use bitcoin::secp256k1;
-       use prelude::*;
-       use sync::Arc;
+       use crate::prelude::*;
+       use crate::sync::Arc;
 
        fn create_network_graph() -> NetworkGraph<Arc<test_utils::TestLogger>> {
                let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
@@ -1872,6 +1979,7 @@ mod tests {
        }
 
        #[test]
+       #[cfg(feature = "std")]
        fn request_full_sync_finite_times() {
                let network_graph = create_network_graph();
                let (secp_ctx, gossip_sync) = create_gossip_sync(&network_graph);
@@ -1888,7 +1996,7 @@ mod tests {
        fn get_signed_node_announcement<F: Fn(&mut UnsignedNodeAnnouncement)>(f: F, node_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> NodeAnnouncement {
                let node_id = PublicKey::from_secret_key(&secp_ctx, node_key);
                let mut unsigned_announcement = UnsignedNodeAnnouncement {
-                       features: NodeFeatures::known(),
+                       features: channelmanager::provided_node_features(),
                        timestamp: 100,
                        node_id: node_id,
                        rgb: [0; 3],
@@ -1912,7 +2020,7 @@ mod tests {
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();
 
                let mut unsigned_announcement = UnsignedChannelAnnouncement {
-                       features: ChannelFeatures::known(),
+                       features: channelmanager::provided_channel_features(),
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 0,
                        node_id_1,
@@ -1933,14 +2041,10 @@ mod tests {
        }
 
        fn get_channel_script(secp_ctx: &Secp256k1<secp256k1::All>) -> Script {
-               let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
-               let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();
-               Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
-                             .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_1_btckey).serialize())
-                             .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_2_btckey).serialize())
-                             .push_opcode(opcodes::all::OP_PUSHNUM_2)
-                             .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script()
-                             .to_v0_p2wsh()
+               let node_1_btckey = SecretKey::from_slice(&[40; 32]).unwrap();
+               let node_2_btckey = SecretKey::from_slice(&[39; 32]).unwrap();
+               make_funding_redeemscript(&PublicKey::from_secret_key(secp_ctx, &node_1_btckey),
+                       &PublicKey::from_secret_key(secp_ctx, &node_2_btckey)).to_v0_p2wsh()
        }
 
        fn get_signed_channel_update<F: Fn(&mut UnsignedChannelUpdate)>(f: F, node_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> ChannelUpdate {
@@ -2055,7 +2159,7 @@ mod tests {
                // drop new one on the floor, since we can't see any changes.
                match gossip_sync.handle_channel_announcement(&valid_announcement) {
                        Ok(_) => panic!(),
-                       Err(e) => assert_eq!(e.err, "Already have knowledge of channel")
+                       Err(e) => assert_eq!(e.err, "Already have non-chain-validated channel")
                };
 
                // Test if an associated transaction were not on-chain (or not confirmed).
@@ -2089,36 +2193,43 @@ mod tests {
                        };
                }
 
-               // If we receive announcement for the same channel (but TX is not confirmed),
-               // drop new one on the floor, since we can't see any changes.
-               *chain_source.utxo_ret.lock().unwrap() = Err(chain::AccessError::UnknownTx);
+               // If we receive announcement for the same channel, once we've validated it against the
+               // chain, we simply ignore all new (duplicate) announcements.
+               *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: 0, script_pubkey: good_script });
                match gossip_sync.handle_channel_announcement(&valid_announcement) {
                        Ok(_) => panic!(),
-                       Err(e) => assert_eq!(e.err, "Channel announced without corresponding UTXO entry")
+                       Err(e) => assert_eq!(e.err, "Already have chain-validated channel")
                };
 
-               // But if it is confirmed, replace the channel
-               *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: 0, script_pubkey: good_script });
-               let valid_announcement = get_signed_channel_announcement(|unsigned_announcement| {
-                       unsigned_announcement.features = ChannelFeatures::empty();
-                       unsigned_announcement.short_channel_id += 2;
-               }, node_1_privkey, node_2_privkey, &secp_ctx);
-               match gossip_sync.handle_channel_announcement(&valid_announcement) {
-                       Ok(res) => assert!(res),
-                       _ => panic!()
-               };
+               #[cfg(feature = "std")]
                {
-                       match network_graph.read_only().channels().get(&valid_announcement.contents.short_channel_id) {
-                               Some(channel_entry) => {
-                                       assert_eq!(channel_entry.features, ChannelFeatures::empty());
-                               },
+                       use std::time::{SystemTime, UNIX_EPOCH};
+
+                       let tracking_time = SystemTime::now().duration_since(UNIX_EPOCH).expect("Time must be > 1970").as_secs();
+                       // Mark a node as permanently failed so it's tracked as removed.
+                       gossip_sync.network_graph().node_failed_permanent(&PublicKey::from_secret_key(&secp_ctx, node_1_privkey));
+
+                       // Return error and ignore valid channel announcement if one of the nodes has been tracked as removed.
+                       let valid_announcement = get_signed_channel_announcement(|unsigned_announcement| {
+                               unsigned_announcement.short_channel_id += 3;
+                       }, node_1_privkey, node_2_privkey, &secp_ctx);
+                       match gossip_sync.handle_channel_announcement(&valid_announcement) {
+                               Ok(_) => panic!(),
+                               Err(e) => assert_eq!(e.err, "Channel with SCID 3 or one of its nodes was removed from our network graph recently")
+                       }
+
+                       gossip_sync.network_graph().remove_stale_channels_and_tracking_with_time(tracking_time + REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS);
+
+                       // The above channel announcement should be handled as per normal now.
+                       match gossip_sync.handle_channel_announcement(&valid_announcement) {
+                               Ok(res) => assert!(res),
                                _ => panic!()
-                       };
+                       }
                }
 
                // Don't relay valid channels with excess data
                let valid_announcement = get_signed_channel_announcement(|unsigned_announcement| {
-                       unsigned_announcement.short_channel_id += 3;
+                       unsigned_announcement.short_channel_id += 4;
                        unsigned_announcement.excess_data.resize(MAX_EXCESS_BYTES_FOR_RELAY + 1, 0);
                }, node_1_privkey, node_2_privkey, &secp_ctx);
                match gossip_sync.handle_channel_announcement(&valid_announcement) {
@@ -2253,6 +2364,7 @@ mod tests {
 
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
+               let node_2_id = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
 
                {
                        // There is no nodes in the table at the beginning.
@@ -2274,7 +2386,7 @@ mod tests {
                        network_graph.handle_event(&Event::PaymentPathFailed {
                                payment_id: None,
                                payment_hash: PaymentHash([0; 32]),
-                               rejected_by_dest: false,
+                               payment_failed_permanently: false,
                                all_paths_failed: true,
                                path: vec![],
                                network_update: Some(NetworkUpdate::ChannelUpdateMessage {
@@ -2301,7 +2413,7 @@ mod tests {
                        network_graph.handle_event(&Event::PaymentPathFailed {
                                payment_id: None,
                                payment_hash: PaymentHash([0; 32]),
-                               rejected_by_dest: false,
+                               payment_failed_permanently: false,
                                all_paths_failed: true,
                                path: vec![],
                                network_update: Some(NetworkUpdate::ChannelFailure {
@@ -2326,7 +2438,7 @@ mod tests {
                network_graph.handle_event(&Event::PaymentPathFailed {
                        payment_id: None,
                        payment_hash: PaymentHash([0; 32]),
-                       rejected_by_dest: false,
+                       payment_failed_permanently: false,
                        all_paths_failed: true,
                        path: vec![],
                        network_update: Some(NetworkUpdate::ChannelFailure {
@@ -2342,12 +2454,64 @@ mod tests {
                assert_eq!(network_graph.read_only().channels().len(), 0);
                // Nodes are also deleted because there are no associated channels anymore
                assert_eq!(network_graph.read_only().nodes().len(), 0);
-               // TODO: Test NetworkUpdate::NodeFailure, which is not implemented yet.
+
+               {
+                       // Get a new network graph since we don't want to track removed nodes in this test with "std"
+                       let network_graph = NetworkGraph::new(genesis_hash, &logger);
+
+                       // Announce a channel to test permanent node failure
+                       let valid_channel_announcement = get_signed_channel_announcement(|_| {}, node_1_privkey, node_2_privkey, &secp_ctx);
+                       let short_channel_id = valid_channel_announcement.contents.short_channel_id;
+                       let chain_source: Option<&test_utils::TestChainSource> = None;
+                       assert!(network_graph.update_channel_from_announcement(&valid_channel_announcement, &chain_source).is_ok());
+                       assert!(network_graph.read_only().channels().get(&short_channel_id).is_some());
+
+                       // Non-permanent node failure does not delete any nodes or channels
+                       network_graph.handle_event(&Event::PaymentPathFailed {
+                               payment_id: None,
+                               payment_hash: PaymentHash([0; 32]),
+                               payment_failed_permanently: false,
+                               all_paths_failed: true,
+                               path: vec![],
+                               network_update: Some(NetworkUpdate::NodeFailure {
+                                       node_id: node_2_id,
+                                       is_permanent: false,
+                               }),
+                               short_channel_id: None,
+                               retry: None,
+                               error_code: None,
+                               error_data: None,
+                       });
+
+                       assert!(network_graph.read_only().channels().get(&short_channel_id).is_some());
+                       assert!(network_graph.read_only().nodes().get(&NodeId::from_pubkey(&node_2_id)).is_some());
+
+                       // Permanent node failure deletes node and its channels
+                       network_graph.handle_event(&Event::PaymentPathFailed {
+                               payment_id: None,
+                               payment_hash: PaymentHash([0; 32]),
+                               payment_failed_permanently: false,
+                               all_paths_failed: true,
+                               path: vec![],
+                               network_update: Some(NetworkUpdate::NodeFailure {
+                                       node_id: node_2_id,
+                                       is_permanent: true,
+                               }),
+                               short_channel_id: None,
+                               retry: None,
+                               error_code: None,
+                               error_data: None,
+                       });
+
+                       assert_eq!(network_graph.read_only().nodes().len(), 0);
+                       // Channels are also deleted because the associated node has been deleted
+                       assert_eq!(network_graph.read_only().channels().len(), 0);
+               }
        }
 
        #[test]
        fn test_channel_timeouts() {
-               // Test the removal of channels with `remove_stale_channels`.
+               // Test the removal of channels with `remove_stale_channels_and_tracking`.
                let logger = test_utils::TestLogger::new();
                let chain_source = test_utils::TestChainSource::new(Network::Testnet);
                let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
@@ -2364,32 +2528,120 @@ mod tests {
                assert!(network_graph.update_channel_from_announcement(&valid_channel_announcement, &chain_source).is_ok());
                assert!(network_graph.read_only().channels().get(&short_channel_id).is_some());
 
+               // Submit two channel updates for each channel direction (update.flags bit).
                let valid_channel_update = get_signed_channel_update(|_| {}, node_1_privkey, &secp_ctx);
                assert!(gossip_sync.handle_channel_update(&valid_channel_update).is_ok());
                assert!(network_graph.read_only().channels().get(&short_channel_id).unwrap().one_to_two.is_some());
 
-               network_graph.remove_stale_channels_with_time(100 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS);
+               let valid_channel_update_2 = get_signed_channel_update(|update| {update.flags |=1;}, node_2_privkey, &secp_ctx);
+               gossip_sync.handle_channel_update(&valid_channel_update_2).unwrap();
+               assert!(network_graph.read_only().channels().get(&short_channel_id).unwrap().two_to_one.is_some());
+
+               network_graph.remove_stale_channels_and_tracking_with_time(100 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS);
                assert_eq!(network_graph.read_only().channels().len(), 1);
                assert_eq!(network_graph.read_only().nodes().len(), 2);
 
-               network_graph.remove_stale_channels_with_time(101 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS);
+               network_graph.remove_stale_channels_and_tracking_with_time(101 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS);
+               #[cfg(not(feature = "std"))] {
+                       // Make sure removed channels are tracked.
+                       assert_eq!(network_graph.removed_channels.lock().unwrap().len(), 1);
+               }
+               network_graph.remove_stale_channels_and_tracking_with_time(101 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS +
+                       REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS);
+
                #[cfg(feature = "std")]
                {
                        // In std mode, a further check is performed before fully removing the channel -
                        // the channel_announcement must have been received at least two weeks ago. We
-                       // fudge that here by indicating the time has jumped two weeks. Note that the
-                       // directional channel information will have been removed already..
+                       // fudge that here by indicating the time has jumped two weeks.
                        assert_eq!(network_graph.read_only().channels().len(), 1);
                        assert_eq!(network_graph.read_only().nodes().len(), 2);
-                       assert!(network_graph.read_only().channels().get(&short_channel_id).unwrap().one_to_two.is_none());
 
+                       // Note that the directional channel information will have been removed already..
+                       // We want to check that this will work even if *one* of the channel updates is recent,
+                       // so we should add it with a recent timestamp.
+                       assert!(network_graph.read_only().channels().get(&short_channel_id).unwrap().one_to_two.is_none());
                        use std::time::{SystemTime, UNIX_EPOCH};
                        let announcement_time = SystemTime::now().duration_since(UNIX_EPOCH).expect("Time must be > 1970").as_secs();
-                       network_graph.remove_stale_channels_with_time(announcement_time + 1 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS);
+                       let valid_channel_update = get_signed_channel_update(|unsigned_channel_update| {
+                               unsigned_channel_update.timestamp = (announcement_time + 1 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS) as u32;
+                       }, node_1_privkey, &secp_ctx);
+                       assert!(gossip_sync.handle_channel_update(&valid_channel_update).is_ok());
+                       assert!(network_graph.read_only().channels().get(&short_channel_id).unwrap().one_to_two.is_some());
+                       network_graph.remove_stale_channels_and_tracking_with_time(announcement_time + 1 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS);
+                       // Make sure removed channels are tracked.
+                       assert_eq!(network_graph.removed_channels.lock().unwrap().len(), 1);
+                       // Provide a later time so that sufficient time has passed
+                       network_graph.remove_stale_channels_and_tracking_with_time(announcement_time + 1 + STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS +
+                               REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS);
                }
 
                assert_eq!(network_graph.read_only().channels().len(), 0);
                assert_eq!(network_graph.read_only().nodes().len(), 0);
+               assert!(network_graph.removed_channels.lock().unwrap().is_empty());
+
+               #[cfg(feature = "std")]
+               {
+                       use std::time::{SystemTime, UNIX_EPOCH};
+
+                       let tracking_time = SystemTime::now().duration_since(UNIX_EPOCH).expect("Time must be > 1970").as_secs();
+
+                       // Clear tracked nodes and channels for clean slate
+                       network_graph.removed_channels.lock().unwrap().clear();
+                       network_graph.removed_nodes.lock().unwrap().clear();
+
+                       // Add a channel and nodes from channel announcement. So our network graph will
+                       // now only consist of two nodes and one channel between them.
+                       assert!(network_graph.update_channel_from_announcement(
+                               &valid_channel_announcement, &chain_source).is_ok());
+
+                       // Mark the channel as permanently failed. This will also remove the two nodes
+                       // and all of the entries will be tracked as removed.
+                       network_graph.channel_failed(short_channel_id, true);
+
+                       // Should not remove from tracking if insufficient time has passed
+                       network_graph.remove_stale_channels_and_tracking_with_time(
+                               tracking_time + REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS - 1);
+                       assert_eq!(network_graph.removed_channels.lock().unwrap().len(), 1);
+
+                       // Provide a later time so that sufficient time has passed
+                       network_graph.remove_stale_channels_and_tracking_with_time(
+                               tracking_time + REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS);
+                       assert!(network_graph.removed_channels.lock().unwrap().is_empty());
+                       assert!(network_graph.removed_nodes.lock().unwrap().is_empty());
+               }
+
+               #[cfg(not(feature = "std"))]
+               {
+                       // When we don't have access to the system clock, the time we started tracking removal will only
+                       // be that provided by the first call to `remove_stale_channels_and_tracking_with_time`. Hence,
+                       // only if sufficient time has passed after that first call, will the next call remove it from
+                       // tracking.
+                       let removal_time = 1664619654;
+
+                       // Clear removed nodes and channels for clean slate
+                       network_graph.removed_channels.lock().unwrap().clear();
+                       network_graph.removed_nodes.lock().unwrap().clear();
+
+                       // Add a channel and nodes from channel announcement. So our network graph will
+                       // now only consist of two nodes and one channel between them.
+                       assert!(network_graph.update_channel_from_announcement(
+                               &valid_channel_announcement, &chain_source).is_ok());
+
+                       // Mark the channel as permanently failed. This will also remove the two nodes
+                       // and all of the entries will be tracked as removed.
+                       network_graph.channel_failed(short_channel_id, true);
+
+                       // The first time we call the following, the channel will have a removal time assigned.
+                       network_graph.remove_stale_channels_and_tracking_with_time(removal_time);
+                       assert_eq!(network_graph.removed_channels.lock().unwrap().len(), 1);
+
+                       // Provide a later time so that sufficient time has passed
+                       network_graph.remove_stale_channels_and_tracking_with_time(
+                               removal_time + REMOVED_ENTRIES_TRACKING_AGE_LIMIT_SECS);
+                       assert!(network_graph.removed_channels.lock().unwrap().is_empty());
+                       assert!(network_graph.removed_nodes.lock().unwrap().is_empty());
+               }
        }
 
        #[test]
@@ -2400,8 +2652,8 @@ mod tests {
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
 
                // Channels were not announced yet.
-               let channels_with_announcements = gossip_sync.get_next_channel_announcements(0, 1);
-               assert_eq!(channels_with_announcements.len(), 0);
+               let channels_with_announcements = gossip_sync.get_next_channel_announcement(0);
+               assert!(channels_with_announcements.is_none());
 
                let short_channel_id;
                {
@@ -2415,17 +2667,15 @@ mod tests {
                }
 
                // Contains initial channel announcement now.
-               let channels_with_announcements = gossip_sync.get_next_channel_announcements(short_channel_id, 1);
-               assert_eq!(channels_with_announcements.len(), 1);
-               if let Some(channel_announcements) = channels_with_announcements.first() {
-                       let &(_, ref update_1, ref update_2) = channel_announcements;
+               let channels_with_announcements = gossip_sync.get_next_channel_announcement(short_channel_id);
+               if let Some(channel_announcements) = channels_with_announcements {
+                       let (_, ref update_1, ref update_2) = channel_announcements;
                        assert_eq!(update_1, &None);
                        assert_eq!(update_2, &None);
                } else {
                        panic!();
                }
 
-
                {
                        // Valid channel update
                        let valid_channel_update = get_signed_channel_update(|unsigned_channel_update| {
@@ -2438,10 +2688,9 @@ mod tests {
                }
 
                // Now contains an initial announcement and an update.
-               let channels_with_announcements = gossip_sync.get_next_channel_announcements(short_channel_id, 1);
-               assert_eq!(channels_with_announcements.len(), 1);
-               if let Some(channel_announcements) = channels_with_announcements.first() {
-                       let &(_, ref update_1, ref update_2) = channel_announcements;
+               let channels_with_announcements = gossip_sync.get_next_channel_announcement(short_channel_id);
+               if let Some(channel_announcements) = channels_with_announcements {
+                       let (_, ref update_1, ref update_2) = channel_announcements;
                        assert_ne!(update_1, &None);
                        assert_eq!(update_2, &None);
                } else {
@@ -2461,10 +2710,9 @@ mod tests {
                }
 
                // Test that announcements with excess data won't be returned
-               let channels_with_announcements = gossip_sync.get_next_channel_announcements(short_channel_id, 1);
-               assert_eq!(channels_with_announcements.len(), 1);
-               if let Some(channel_announcements) = channels_with_announcements.first() {
-                       let &(_, ref update_1, ref update_2) = channel_announcements;
+               let channels_with_announcements = gossip_sync.get_next_channel_announcement(short_channel_id);
+               if let Some(channel_announcements) = channels_with_announcements {
+                       let (_, ref update_1, ref update_2) = channel_announcements;
                        assert_eq!(update_1, &None);
                        assert_eq!(update_2, &None);
                } else {
@@ -2472,8 +2720,8 @@ mod tests {
                }
 
                // Further starting point have no channels after it
-               let channels_with_announcements = gossip_sync.get_next_channel_announcements(short_channel_id + 1000, 1);
-               assert_eq!(channels_with_announcements.len(), 0);
+               let channels_with_announcements = gossip_sync.get_next_channel_announcement(short_channel_id + 1000);
+               assert!(channels_with_announcements.is_none());
        }
 
        #[test]
@@ -2485,8 +2733,8 @@ mod tests {
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
 
                // No nodes yet.
-               let next_announcements = gossip_sync.get_next_node_announcements(None, 10);
-               assert_eq!(next_announcements.len(), 0);
+               let next_announcements = gossip_sync.get_next_node_announcement(None);
+               assert!(next_announcements.is_none());
 
                {
                        // Announce a channel to add 2 nodes
@@ -2497,10 +2745,9 @@ mod tests {
                        };
                }
 
-
                // Nodes were never announced
-               let next_announcements = gossip_sync.get_next_node_announcements(None, 3);
-               assert_eq!(next_announcements.len(), 0);
+               let next_announcements = gossip_sync.get_next_node_announcement(None);
+               assert!(next_announcements.is_none());
 
                {
                        let valid_announcement = get_signed_node_announcement(|_| {}, node_1_privkey, &secp_ctx);
@@ -2516,12 +2763,12 @@ mod tests {
                        };
                }
 
-               let next_announcements = gossip_sync.get_next_node_announcements(None, 3);
-               assert_eq!(next_announcements.len(), 2);
+               let next_announcements = gossip_sync.get_next_node_announcement(None);
+               assert!(next_announcements.is_some());
 
                // Skip the first node.
-               let next_announcements = gossip_sync.get_next_node_announcements(Some(&node_id_1), 2);
-               assert_eq!(next_announcements.len(), 1);
+               let next_announcements = gossip_sync.get_next_node_announcement(Some(&node_id_1));
+               assert!(next_announcements.is_some());
 
                {
                        // Later announcement which should not be relayed (excess data) prevent us from sharing a node
@@ -2535,8 +2782,8 @@ mod tests {
                        };
                }
 
-               let next_announcements = gossip_sync.get_next_node_announcements(Some(&node_id_1), 2);
-               assert_eq!(next_announcements.len(), 0);
+               let next_announcements = gossip_sync.get_next_node_announcement(Some(&node_id_1));
+               assert!(next_announcements.is_none());
        }
 
        #[test]
@@ -2587,6 +2834,7 @@ mod tests {
        #[cfg(feature = "std")]
        fn calling_sync_routing_table() {
                use std::time::{SystemTime, UNIX_EPOCH};
+               use crate::ln::msgs::Init;
 
                let network_graph = create_network_graph();
                let (secp_ctx, gossip_sync) = create_gossip_sync(&network_graph);
@@ -2597,16 +2845,18 @@ mod tests {
 
                // It should ignore if gossip_queries feature is not enabled
                {
-                       let init_msg = Init { features: InitFeatures::known().clear_gossip_queries(), remote_network_address: None };
-                       gossip_sync.peer_connected(&node_id_1, &init_msg);
+                       let init_msg = Init { features: InitFeatures::empty(), remote_network_address: None };
+                       gossip_sync.peer_connected(&node_id_1, &init_msg).unwrap();
                        let events = gossip_sync.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 0);
                }
 
                // It should send a gossip_timestamp_filter with the correct information
                {
-                       let init_msg = Init { features: InitFeatures::known(), remote_network_address: None };
-                       gossip_sync.peer_connected(&node_id_1, &init_msg);
+                       let mut features = InitFeatures::empty();
+                       features.set_gossip_queries_optional();
+                       let init_msg = Init { features, remote_network_address: None };
+                       gossip_sync.peer_connected(&node_id_1, &init_msg).unwrap();
                        let events = gossip_sync.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
@@ -2955,10 +3205,10 @@ mod tests {
 
        #[test]
        fn channel_info_is_readable() {
-               let chanmon_cfgs = ::ln::functional_test_utils::create_chanmon_cfgs(2);
-               let node_cfgs = ::ln::functional_test_utils::create_node_cfgs(2, &chanmon_cfgs);
-               let node_chanmgrs = ::ln::functional_test_utils::create_node_chanmgrs(2, &node_cfgs, &[None, None, None, None]);
-               let nodes = ::ln::functional_test_utils::create_network(2, &node_cfgs, &node_chanmgrs);
+               let chanmon_cfgs = crate::ln::functional_test_utils::create_chanmon_cfgs(2);
+               let node_cfgs = crate::ln::functional_test_utils::create_node_cfgs(2, &chanmon_cfgs);
+               let node_chanmgrs = crate::ln::functional_test_utils::create_node_chanmgrs(2, &node_cfgs, &[None, None, None, None]);
+               let nodes = crate::ln::functional_test_utils::create_network(2, &node_cfgs, &node_chanmgrs);
 
                // 1. Test encoding/decoding of ChannelUpdateInfo
                let chan_update_info = ChannelUpdateInfo {
@@ -2975,7 +3225,7 @@ mod tests {
                assert!(chan_update_info.write(&mut encoded_chan_update_info).is_ok());
 
                // First make sure we can read ChannelUpdateInfos we just wrote
-               let read_chan_update_info: ChannelUpdateInfo = ::util::ser::Readable::read(&mut encoded_chan_update_info.as_slice()).unwrap();
+               let read_chan_update_info: ChannelUpdateInfo = crate::util::ser::Readable::read(&mut encoded_chan_update_info.as_slice()).unwrap();
                assert_eq!(chan_update_info, read_chan_update_info);
 
                // Check the serialization hasn't changed.
@@ -2985,17 +3235,17 @@ mod tests {
                // Check we fail if htlc_maximum_msat is not present in either the ChannelUpdateInfo itself
                // or the ChannelUpdate enclosed with `last_update_message`.
                let legacy_chan_update_info_with_some_and_fail_update: Vec<u8> = hex::decode("b40004000000170201010402002a060800000000000004d2080909000000000000162e0a0d0c00040000000902040000000a0c8181d977cb9b53d93a6ff64bb5f1e158b4094b66e798fb12911168a3ccdf80a83096340a6a95da0ae8d9f776528eecdbb747eb6b545495a4319ed5378e35b21e073a000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f00083a840000034d013413a70000009000000000000f42400000271000000014").unwrap();
-               let read_chan_update_info_res: Result<ChannelUpdateInfo, ::ln::msgs::DecodeError> = ::util::ser::Readable::read(&mut legacy_chan_update_info_with_some_and_fail_update.as_slice());
+               let read_chan_update_info_res: Result<ChannelUpdateInfo, crate::ln::msgs::DecodeError> = crate::util::ser::Readable::read(&mut legacy_chan_update_info_with_some_and_fail_update.as_slice());
                assert!(read_chan_update_info_res.is_err());
 
                let legacy_chan_update_info_with_none: Vec<u8> = hex::decode("2c0004000000170201010402002a060800000000000004d20801000a0d0c00040000000902040000000a0c0100").unwrap();
-               let read_chan_update_info_res: Result<ChannelUpdateInfo, ::ln::msgs::DecodeError> = ::util::ser::Readable::read(&mut legacy_chan_update_info_with_none.as_slice());
+               let read_chan_update_info_res: Result<ChannelUpdateInfo, crate::ln::msgs::DecodeError> = crate::util::ser::Readable::read(&mut legacy_chan_update_info_with_none.as_slice());
                assert!(read_chan_update_info_res.is_err());
-                       
+
                // 2. Test encoding/decoding of ChannelInfo
                // Check we can encode/decode ChannelInfo without ChannelUpdateInfo fields present.
                let chan_info_none_updates = ChannelInfo {
-                       features: ChannelFeatures::known(),
+                       features: channelmanager::provided_channel_features(),
                        node_one: NodeId::from_pubkey(&nodes[0].node.get_our_node_id()),
                        one_to_two: None,
                        node_two: NodeId::from_pubkey(&nodes[1].node.get_our_node_id()),
@@ -3008,12 +3258,12 @@ mod tests {
                let mut encoded_chan_info: Vec<u8> = Vec::new();
                assert!(chan_info_none_updates.write(&mut encoded_chan_info).is_ok());
 
-               let read_chan_info: ChannelInfo = ::util::ser::Readable::read(&mut encoded_chan_info.as_slice()).unwrap();
+               let read_chan_info: ChannelInfo = crate::util::ser::Readable::read(&mut encoded_chan_info.as_slice()).unwrap();
                assert_eq!(chan_info_none_updates, read_chan_info);
 
                // Check we can encode/decode ChannelInfo with ChannelUpdateInfo fields present.
                let chan_info_some_updates = ChannelInfo {
-                       features: ChannelFeatures::known(),
+                       features: channelmanager::provided_channel_features(),
                        node_one: NodeId::from_pubkey(&nodes[0].node.get_our_node_id()),
                        one_to_two: Some(chan_update_info.clone()),
                        node_two: NodeId::from_pubkey(&nodes[1].node.get_our_node_id()),
@@ -3026,7 +3276,7 @@ mod tests {
                let mut encoded_chan_info: Vec<u8> = Vec::new();
                assert!(chan_info_some_updates.write(&mut encoded_chan_info).is_ok());
 
-               let read_chan_info: ChannelInfo = ::util::ser::Readable::read(&mut encoded_chan_info.as_slice()).unwrap();
+               let read_chan_info: ChannelInfo = crate::util::ser::Readable::read(&mut encoded_chan_info.as_slice()).unwrap();
                assert_eq!(chan_info_some_updates, read_chan_info);
 
                // Check the serialization hasn't changed.
@@ -3036,13 +3286,13 @@ mod tests {
                // Check we can decode legacy ChannelInfo, even if the `two_to_one` / `one_to_two` /
                // `last_update_message` fields fail to decode due to missing htlc_maximum_msat.
                let legacy_chan_info_with_some_and_fail_update = hex::decode("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").unwrap();
-               let read_chan_info: ChannelInfo = ::util::ser::Readable::read(&mut legacy_chan_info_with_some_and_fail_update.as_slice()).unwrap();
+               let read_chan_info: ChannelInfo = crate::util::ser::Readable::read(&mut legacy_chan_info_with_some_and_fail_update.as_slice()).unwrap();
                assert_eq!(read_chan_info.announcement_received_time, 87654);
                assert_eq!(read_chan_info.one_to_two, None);
                assert_eq!(read_chan_info.two_to_one, None);
 
                let legacy_chan_info_with_none: Vec<u8> = hex::decode("ba00020000010800000000000156660221027f921585f2ac0c7c70e36110adecfd8fd14b8a99bfb3d000a283fcac358fce88042e2e2c0004000000170201010402002a060800000000000004d20801000a0d0c00040000000902040000000a0c010006210355f8d2238a322d16b602bd0ceaad5b01019fb055971eaadcc9b29226a4da6c23082e2e2c0004000000170201010402002a060800000000000004d20801000a0d0c00040000000902040000000a0c01000a01000c0100").unwrap();
-               let read_chan_info: ChannelInfo = ::util::ser::Readable::read(&mut legacy_chan_info_with_none.as_slice()).unwrap();
+               let read_chan_info: ChannelInfo = crate::util::ser::Readable::read(&mut legacy_chan_info_with_none.as_slice()).unwrap();
                assert_eq!(read_chan_info.announcement_received_time, 87654);
                assert_eq!(read_chan_info.one_to_two, None);
                assert_eq!(read_chan_info.two_to_one, None);
@@ -3053,9 +3303,9 @@ mod tests {
                use std::convert::TryFrom;
 
                // 1. Check we can read a valid NodeAnnouncementInfo and fail on an invalid one
-               let valid_netaddr = ::ln::msgs::NetAddress::Hostname { hostname: ::util::ser::Hostname::try_from("A".to_string()).unwrap(), port: 1234 };
+               let valid_netaddr = crate::ln::msgs::NetAddress::Hostname { hostname: crate::util::ser::Hostname::try_from("A".to_string()).unwrap(), port: 1234 };
                let valid_node_ann_info = NodeAnnouncementInfo {
-                       features: NodeFeatures::known(),
+                       features: channelmanager::provided_node_features(),
                        last_update: 0,
                        rgb: [0u8; 3],
                        alias: NodeAlias([0u8; 32]),
@@ -3065,11 +3315,11 @@ mod tests {
 
                let mut encoded_valid_node_ann_info = Vec::new();
                assert!(valid_node_ann_info.write(&mut encoded_valid_node_ann_info).is_ok());
-               let read_valid_node_ann_info: NodeAnnouncementInfo = ::util::ser::Readable::read(&mut encoded_valid_node_ann_info.as_slice()).unwrap();
+               let read_valid_node_ann_info: NodeAnnouncementInfo = crate::util::ser::Readable::read(&mut encoded_valid_node_ann_info.as_slice()).unwrap();
                assert_eq!(read_valid_node_ann_info, valid_node_ann_info);
 
                let encoded_invalid_node_ann_info = hex::decode("3f0009000788a000080a51a20204000000000403000000062000000000000000000000000000000000000000000000000000000000000000000a0505014004d2").unwrap();
-               let read_invalid_node_ann_info_res: Result<NodeAnnouncementInfo, ::ln::msgs::DecodeError> = ::util::ser::Readable::read(&mut encoded_invalid_node_ann_info.as_slice());
+               let read_invalid_node_ann_info_res: Result<NodeAnnouncementInfo, crate::ln::msgs::DecodeError> = crate::util::ser::Readable::read(&mut encoded_invalid_node_ann_info.as_slice());
                assert!(read_invalid_node_ann_info_res.is_err());
 
                // 2. Check we can read a NodeInfo anyways, but set the NodeAnnouncementInfo to None if invalid
@@ -3081,11 +3331,11 @@ mod tests {
 
                let mut encoded_valid_node_info = Vec::new();
                assert!(valid_node_info.write(&mut encoded_valid_node_info).is_ok());
-               let read_valid_node_info: NodeInfo = ::util::ser::Readable::read(&mut encoded_valid_node_info.as_slice()).unwrap();
+               let read_valid_node_info: NodeInfo = crate::util::ser::Readable::read(&mut encoded_valid_node_info.as_slice()).unwrap();
                assert_eq!(read_valid_node_info, valid_node_info);
 
                let encoded_invalid_node_info_hex = hex::decode("4402403f0009000788a000080a51a20204000000000403000000062000000000000000000000000000000000000000000000000000000000000000000a0505014004d20400").unwrap();
-               let read_invalid_node_info: NodeInfo = ::util::ser::Readable::read(&mut encoded_invalid_node_info_hex.as_slice()).unwrap();
+               let read_invalid_node_info: NodeInfo = crate::util::ser::Readable::read(&mut encoded_invalid_node_info_hex.as_slice()).unwrap();
                assert_eq!(read_invalid_node_info.announcement_info, None);
        }
 }
@@ -3099,8 +3349,8 @@ mod benches {
 
        #[bench]
        fn read_network_graph(bench: &mut Bencher) {
-               let logger = ::util::test_utils::TestLogger::new();
-               let mut d = ::routing::router::test_utils::get_route_file().unwrap();
+               let logger = crate::util::test_utils::TestLogger::new();
+               let mut d = crate::routing::router::bench_utils::get_route_file().unwrap();
                let mut v = Vec::new();
                d.read_to_end(&mut v).unwrap();
                bench.iter(|| {
@@ -3110,8 +3360,8 @@ mod benches {
 
        #[bench]
        fn write_network_graph(bench: &mut Bencher) {
-               let logger = ::util::test_utils::TestLogger::new();
-               let mut d = ::routing::router::test_utils::get_route_file().unwrap();
+               let logger = crate::util::test_utils::TestLogger::new();
+               let mut d = crate::routing::router::bench_utils::get_route_file().unwrap();
                let net_graph = NetworkGraph::read(&mut d, &logger).unwrap();
                bench.iter(|| {
                        let _ = net_graph.encode();