Merge pull request #1524 from ViktorTigerstrom/2022-06-update-fail-holding-cell-htlcs...
[rust-lightning] / lightning / src / routing / router.rs
index 582b6f24491069be1402513d2fa7343e2650c5a7..90e658604ad1058040643e5b6be48fd93cfe29a8 100644 (file)
@@ -9,17 +9,17 @@
 
 //! The top-level routing/network map tracking logic lives here.
 //!
-//! You probably want to create a NetGraphMsgHandler and use that as your RoutingMessageHandler and then
+//! You probably want to create a P2PGossipSync and use that as your RoutingMessageHandler and then
 //! interrogate it to get routes for your own payments.
 
-use bitcoin::secp256k1::key::PublicKey;
+use bitcoin::secp256k1::PublicKey;
 
 use ln::channelmanager::ChannelDetails;
 use ln::features::{ChannelFeatures, InvoiceFeatures, NodeFeatures};
 use ln::msgs::{DecodeError, ErrorAction, LightningError, MAX_VALUE_MSAT};
-use routing::scoring::Score;
-use routing::network_graph::{DirectedChannelInfoWithUpdate, EffectiveCapacity, NetworkGraph, ReadOnlyNetworkGraph, NodeId, RoutingFees};
-use util::ser::{Writeable, Readable};
+use routing::gossip::{DirectedChannelInfoWithUpdate, EffectiveCapacity, ReadOnlyNetworkGraph, NodeId, RoutingFees};
+use routing::scoring::{ChannelUsage, Score};
+use util::ser::{Writeable, Readable, Writer};
 use util::logger::{Level, Logger};
 use util::chacha20::ChaCha20;
 
@@ -65,11 +65,10 @@ impl_writeable_tlv_based!(RouteHop, {
 #[derive(Clone, Hash, PartialEq, Eq)]
 pub struct Route {
        /// The list of routes taken for a single (potentially-)multi-part payment. The pubkey of the
-       /// last RouteHop in each path must be the same.
-       /// Each entry represents a list of hops, NOT INCLUDING our own, where the last hop is the
-       /// destination. Thus, this must always be at least length one. While the maximum length of any
-       /// given path is variable, keeping the length of any path to less than 20 should currently
-       /// ensure it is viable.
+       /// last RouteHop in each path must be the same. Each entry represents a list of hops, NOT
+       /// INCLUDING our own, where the last hop is the destination. Thus, this must always be at
+       /// least length one. While the maximum length of any given path is variable, keeping the length
+       /// of any path less or equal to 19 should currently ensure it is viable.
        pub paths: Vec<Vec<RouteHop>>,
        /// The `payment_params` parameter passed to [`find_route`].
        /// This is used by `ChannelManager` to track information which may be required for retries,
@@ -152,8 +151,8 @@ impl Readable for Route {
 
 /// Parameters needed to find a [`Route`].
 ///
-/// Passed to [`find_route`] and also provided in [`Event::PaymentPathFailed`] for retrying a failed
-/// payment path.
+/// Passed to [`find_route`] and [`build_route_from_hops`], but also provided in
+/// [`Event::PaymentPathFailed`] for retrying a failed payment path.
 ///
 /// [`Event::PaymentPathFailed`]: crate::util::events::Event::PaymentPathFailed
 #[derive(Clone, Debug)]
@@ -177,9 +176,23 @@ impl_writeable_tlv_based!(RouteParameters, {
 /// Maximum total CTLV difference we allow for a full payment path.
 pub const DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA: u32 = 1008;
 
-/// The median hop CLTV expiry delta currently seen in the network.
+// The median hop CLTV expiry delta currently seen in the network.
 const MEDIAN_HOP_CLTV_EXPIRY_DELTA: u32 = 40;
 
+// During routing, we only consider paths shorter than our maximum length estimate.
+// In the legacy onion format, the maximum number of hops used to be a fixed value of 20.
+// However, in the TLV onion format, there is no fixed maximum length, but the `hop_payloads`
+// field is always 1300 bytes. As the `tlv_payload` for each hop may vary in length, we have to
+// estimate how many hops the route may have so that it actually fits the `hop_payloads` field.
+//
+// We estimate 3+32 (payload length and HMAC) + 2+8 (amt_to_forward) + 2+4 (outgoing_cltv_value) +
+// 2+8 (short_channel_id) = 61 bytes for each intermediate hop and 3+32
+// (payload length and HMAC) + 2+8 (amt_to_forward) + 2+4 (outgoing_cltv_value) + 2+32+8
+// (payment_secret and total_msat) = 93 bytes for the final hop.
+// Since the length of the potentially included `payment_metadata` is unknown to us, we round
+// down from (1300-93) / 61 = 19.78... to arrive at a conservative estimate of 19.
+const MAX_PATH_LENGTH_ESTIMATE: u8 = 19;
+
 /// The recipient of a payment.
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct PaymentParameters {
@@ -327,16 +340,16 @@ struct RouteGraphNode {
        /// All penalties incurred from this hop on the way to the destination, as calculated using
        /// channel scoring.
        path_penalty_msat: u64,
+       /// The number of hops walked up to this node.
+       path_length_to_node: u8,
 }
 
 impl cmp::Ord for RouteGraphNode {
        fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
                let other_score = cmp::max(other.lowest_fee_to_peer_through_node, other.path_htlc_minimum_msat)
-                       .checked_add(other.path_penalty_msat)
-                       .unwrap_or_else(|| u64::max_value());
+                       .saturating_add(other.path_penalty_msat);
                let self_score = cmp::max(self.lowest_fee_to_peer_through_node, self.path_htlc_minimum_msat)
-                       .checked_add(self.path_penalty_msat)
-                       .unwrap_or_else(|| u64::max_value());
+                       .saturating_add(self.path_penalty_msat);
                other_score.cmp(&self_score).then_with(|| other.node_id.cmp(&self.node_id))
        }
 }
@@ -356,7 +369,7 @@ enum CandidateRouteHop<'a> {
        FirstHop {
                details: &'a ChannelDetails,
        },
-       /// A hop found in the [`NetworkGraph`], where the channel capacity may or may not be known.
+       /// A hop found in the [`ReadOnlyNetworkGraph`], where the channel capacity may be unknown.
        PublicHop {
                info: DirectedChannelInfoWithUpdate<'a>,
                short_channel_id: u64,
@@ -370,7 +383,7 @@ enum CandidateRouteHop<'a> {
 impl<'a> CandidateRouteHop<'a> {
        fn short_channel_id(&self) -> u64 {
                match self {
-                       CandidateRouteHop::FirstHop { details } => details.short_channel_id.unwrap(),
+                       CandidateRouteHop::FirstHop { details } => details.get_outbound_payment_scid().unwrap(),
                        CandidateRouteHop::PublicHop { short_channel_id, .. } => *short_channel_id,
                        CandidateRouteHop::PrivateHop { hint } => hint.short_channel_id,
                }
@@ -401,6 +414,16 @@ impl<'a> CandidateRouteHop<'a> {
                }
        }
 
+       fn htlc_maximum_msat(&self) -> u64 {
+               match self {
+                       CandidateRouteHop::FirstHop { details } => details.next_outbound_htlc_limit_msat,
+                       CandidateRouteHop::PublicHop { info, .. } => info.htlc_maximum_msat(),
+                       CandidateRouteHop::PrivateHop { hint } => {
+                               hint.htlc_maximum_msat.unwrap_or(u64::max_value())
+                       },
+               }
+       }
+
        fn fees(&self) -> RoutingFees {
                match self {
                        CandidateRouteHop::FirstHop { .. } => RoutingFees {
@@ -414,7 +437,7 @@ impl<'a> CandidateRouteHop<'a> {
        fn effective_capacity(&self) -> EffectiveCapacity {
                match self {
                        CandidateRouteHop::FirstHop { details } => EffectiveCapacity::ExactLiquidity {
-                               liquidity_msat: details.outbound_capacity_msat,
+                               liquidity_msat: details.next_outbound_htlc_limit_msat,
                        },
                        CandidateRouteHop::PublicHop { info, .. } => info.effective_capacity(),
                        CandidateRouteHop::PrivateHop { .. } => EffectiveCapacity::Infinite,
@@ -468,7 +491,8 @@ struct PathBuildingHop<'a> {
 
 impl<'a> core::fmt::Debug for PathBuildingHop<'a> {
        fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
-               f.debug_struct("PathBuildingHop")
+               let mut debug_struct = f.debug_struct("PathBuildingHop");
+               debug_struct
                        .field("node_id", &self.node_id)
                        .field("short_channel_id", &self.candidate.short_channel_id())
                        .field("total_fee_msat", &self.total_fee_msat)
@@ -477,8 +501,11 @@ impl<'a> core::fmt::Debug for PathBuildingHop<'a> {
                        .field("total_fee_msat - (next_hops_fee_msat + hop_use_fee_msat)", &(&self.total_fee_msat - (&self.next_hops_fee_msat + &self.hop_use_fee_msat)))
                        .field("path_penalty_msat", &self.path_penalty_msat)
                        .field("path_htlc_minimum_msat", &self.path_htlc_minimum_msat)
-                       .field("cltv_expiry_delta", &self.candidate.cltv_expiry_delta())
-                       .finish()
+                       .field("cltv_expiry_delta", &self.candidate.cltv_expiry_delta());
+               #[cfg(all(not(feature = "_bench_unstable"), any(test, fuzzing)))]
+               let debug_struct = debug_struct
+                       .field("value_contribution_msat", &self.value_contribution_msat);
+               debug_struct.finish()
        }
 }
 
@@ -495,6 +522,10 @@ impl<'a> PaymentPath<'a> {
                self.hops.last().unwrap().0.fee_msat
        }
 
+       fn get_path_penalty_msat(&self) -> u64 {
+               self.hops.first().map(|h| h.0.path_penalty_msat).unwrap_or(u64::max_value())
+       }
+
        fn get_total_fee_paid_msat(&self) -> u64 {
                if self.hops.len() < 1 {
                        return 0;
@@ -509,6 +540,10 @@ impl<'a> PaymentPath<'a> {
                return result;
        }
 
+       fn get_cost_msat(&self) -> u64 {
+               self.get_total_fee_paid_msat().saturating_add(self.get_path_penalty_msat())
+       }
+
        // If the amount transferred by the path is updated, the fees should be adjusted. Any other way
        // to change fees may result in an inconsistency.
        //
@@ -596,6 +631,17 @@ fn compute_fees(amount_msat: u64, channel_fees: RoutingFees) -> Option<u64> {
        }
 }
 
+/// The default `features` we assume for a node in a route, when no `features` are known about that
+/// specific node.
+///
+/// Default features are:
+/// * variable_length_onion_optional
+fn default_node_features() -> NodeFeatures {
+       let mut features = NodeFeatures::empty();
+       features.set_variable_length_onion_optional();
+       features
+}
+
 /// Finds a route from us (payer) to the given target node (payee).
 ///
 /// If the payee provided features in their invoice, they should be provided via `params.payee`.
@@ -604,8 +650,8 @@ fn compute_fees(amount_msat: u64, channel_fees: RoutingFees) -> Option<u64> {
 /// Private routing paths between a public node and the target may be included in `params.payee`.
 ///
 /// If some channels aren't announced, it may be useful to fill in `first_hops` with the results
-/// from [`ChannelManager::list_usable_channels`]. If it is filled in, the view of our local
-/// channels from [`NetworkGraph`] will be ignored, and only those in `first_hops` will be used.
+/// from [`ChannelManager::list_usable_channels`]. If it is filled in, the view of these channels
+/// from `network_graph` will be ignored, and only those in `first_hops` will be used.
 ///
 /// The fees on channels from us to the next hop are ignored as they are assumed to all be equal.
 /// However, the enabled/disabled bit on such channels as well as the `htlc_minimum_msat` /
@@ -624,28 +670,24 @@ fn compute_fees(amount_msat: u64, channel_fees: RoutingFees) -> Option<u64> {
 ///
 /// [`ChannelManager::list_usable_channels`]: crate::ln::channelmanager::ChannelManager::list_usable_channels
 /// [`Event::PaymentPathFailed`]: crate::util::events::Event::PaymentPathFailed
+/// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
 pub fn find_route<L: Deref, S: Score>(
-       our_node_pubkey: &PublicKey, route_params: &RouteParameters, network: &NetworkGraph,
-       first_hops: Option<&[&ChannelDetails]>, logger: L, scorer: &S, random_seed_bytes: &[u8; 32]
+       our_node_pubkey: &PublicKey, route_params: &RouteParameters,
+       network_graph: &ReadOnlyNetworkGraph, first_hops: Option<&[&ChannelDetails]>, logger: L,
+       scorer: &S, random_seed_bytes: &[u8; 32]
 ) -> Result<Route, LightningError>
 where L::Target: Logger {
-       let network_graph = network.read_only();
-       match get_route(
-               our_node_pubkey, &route_params.payment_params, &network_graph, first_hops, route_params.final_value_msat,
-               route_params.final_cltv_expiry_delta, logger, scorer, random_seed_bytes
-       ) {
-               Ok(mut route) => {
-                       add_random_cltv_offset(&mut route, &route_params.payment_params, &network_graph, random_seed_bytes);
-                       Ok(route)
-               },
-               Err(err) => Err(err),
-       }
+       let mut route = get_route(our_node_pubkey, &route_params.payment_params, network_graph, first_hops,
+               route_params.final_value_msat, route_params.final_cltv_expiry_delta, logger, scorer,
+               random_seed_bytes)?;
+       add_random_cltv_offset(&mut route, &route_params.payment_params, network_graph, random_seed_bytes);
+       Ok(route)
 }
 
 pub(crate) fn get_route<L: Deref, S: Score>(
        our_node_pubkey: &PublicKey, payment_params: &PaymentParameters, network_graph: &ReadOnlyNetworkGraph,
        first_hops: Option<&[&ChannelDetails]>, final_value_msat: u64, final_cltv_expiry_delta: u32,
-       logger: L, scorer: &S, _random_seed_bytes: &[u8; 32]
+       logger: L, scorer: &S, random_seed_bytes: &[u8; 32]
 ) -> Result<Route, LightningError>
 where L::Target: Logger {
        let payee_node_id = NodeId::from_pubkey(&payment_params.payee_pubkey);
@@ -670,6 +712,9 @@ where L::Target: Logger {
                        }
                }
        }
+       if payment_params.max_total_cltv_expiry_delta <= final_cltv_expiry_delta {
+               return Err(LightningError{err: "Can't find a route where the maximum total CLTV expiry delta is below the final CLTV expiry.".to_owned(), action: ErrorAction::IgnoreError});
+       }
 
        // The general routing idea is the following:
        // 1. Fill first/last hops communicated by the caller.
@@ -757,7 +802,7 @@ where L::Target: Logger {
                HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
        if let Some(hops) = first_hops {
                for chan in hops {
-                       if chan.short_channel_id.is_none() {
+                       if chan.get_outbound_payment_scid().is_none() {
                                panic!("first_hops should be filled in with usable channels, not pending ones");
                        }
                        if chan.counterparty.node_id == *our_node_pubkey {
@@ -776,11 +821,11 @@ where L::Target: Logger {
        // The main heap containing all candidate next-hops sorted by their score (max(A* fee,
        // htlc_minimum)). Ideally this would be a heap which allowed cheap score reduction instead of
        // adding duplicate entries when we find a better path to a given node.
-       let mut targets = BinaryHeap::new();
+       let mut targets: BinaryHeap<RouteGraphNode> = BinaryHeap::new();
 
        // Map from node_id to information about the best current path to that node, including feerate
        // information.
-       let mut dist = HashMap::with_capacity(network_nodes.len());
+       let mut dist: HashMap<NodeId, PathBuildingHop> = HashMap::with_capacity(network_nodes.len());
 
        // During routing, if we ignore a path due to an htlc_minimum_msat limit, we set this,
        // indicating that we may wish to try again with a higher value, potentially paying to meet an
@@ -795,11 +840,12 @@ where L::Target: Logger {
        let recommended_value_msat = final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR as u64;
        let mut path_value_msat = final_value_msat;
 
-       // We don't want multiple paths (as per MPP) share liquidity of the same channels.
-       // This map allows paths to be aware of the channel use by other paths in the same call.
-       // This would help to make a better path finding decisions and not "overbook" channels.
-       // It is unaware of the directions (except for `outbound_capacity_msat` in `first_hops`).
-       let mut bookkept_channels_liquidity_available_msat = HashMap::with_capacity(network_nodes.len());
+       // Keep track of how much liquidity has been used in selected channels. Used to determine
+       // if the channel can be used by additional MPP paths or to inform path finding decisions. It is
+       // aware of direction *only* to ensure that the correct htlc_maximum_msat value is used. Hence,
+       // liquidity used in one direction will not offset any used in the opposite direction.
+       let mut used_channel_liquidities: HashMap<(u64, bool), u64> =
+               HashMap::with_capacity(network_nodes.len());
 
        // Keeping track of how much value we already collected across other paths. Helps to decide:
        // - how much a new path should be transferring (upper bound);
@@ -808,6 +854,29 @@ where L::Target: Logger {
        // - when we want to stop looking for new paths.
        let mut already_collected_value_msat = 0;
 
+       for (_, channels) in first_hop_targets.iter_mut() {
+               // Sort the first_hops channels to the same node(s) in priority order of which channel we'd
+               // most like to use.
+               //
+               // First, if channels are below `recommended_value_msat`, sort them in descending order,
+               // preferring larger channels to avoid splitting the payment into more MPP parts than is
+               // required.
+               //
+               // Second, because simply always sorting in descending order would always use our largest
+               // available outbound capacity, needlessly fragmenting our available channel capacities,
+               // sort channels above `recommended_value_msat` in ascending order, preferring channels
+               // which have enough, but not too much, capacity for the payment.
+               channels.sort_unstable_by(|chan_a, chan_b| {
+                       if chan_b.next_outbound_htlc_limit_msat < recommended_value_msat || chan_a.next_outbound_htlc_limit_msat < recommended_value_msat {
+                               // Sort in descending order
+                               chan_b.next_outbound_htlc_limit_msat.cmp(&chan_a.next_outbound_htlc_limit_msat)
+                       } else {
+                               // Sort in ascending order
+                               chan_a.next_outbound_htlc_limit_msat.cmp(&chan_b.next_outbound_htlc_limit_msat)
+                       }
+               });
+       }
+
        log_trace!(logger, "Building path from {} (payee) to {} (us/payer) for value {} msat.", payment_params.payee_pubkey, our_node_pubkey, final_value_msat);
 
        macro_rules! add_entry {
@@ -816,8 +885,8 @@ where L::Target: Logger {
                // since that value has to be transferred over this channel.
                // Returns whether this channel caused an update to `targets`.
                ( $candidate: expr, $src_node_id: expr, $dest_node_id: expr, $next_hops_fee_msat: expr,
-                  $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr,
-                  $next_hops_path_penalty_msat: expr, $next_hops_cltv_delta: expr ) => { {
+                       $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr,
+                       $next_hops_path_penalty_msat: expr, $next_hops_cltv_delta: expr, $next_hops_path_length: expr ) => { {
                        // We "return" whether we updated the path at the end, via this:
                        let mut did_add_update_path_to_src_node = false;
                        // Channels to self should not be used. This is more of belt-and-suspenders, because in
@@ -826,18 +895,23 @@ where L::Target: Logger {
                        // - for first and last hops early in get_route
                        if $src_node_id != $dest_node_id {
                                let short_channel_id = $candidate.short_channel_id();
-                               let available_liquidity_msat = bookkept_channels_liquidity_available_msat
-                                       .entry(short_channel_id)
-                                       .or_insert_with(|| $candidate.effective_capacity().as_msat());
+                               let htlc_maximum_msat = $candidate.htlc_maximum_msat();
 
-                               // It is tricky to substract $next_hops_fee_msat from available liquidity here.
+                               // It is tricky to subtract $next_hops_fee_msat from available liquidity here.
                                // It may be misleading because we might later choose to reduce the value transferred
                                // over these channels, and the channel which was insufficient might become sufficient.
                                // Worst case: we drop a good channel here because it can't cover the high following
                                // fees caused by one expensive channel, but then this channel could have been used
                                // if the amount being transferred over this path is lower.
                                // We do this for now, but this is a subject for removal.
-                               if let Some(available_value_contribution_msat) = available_liquidity_msat.checked_sub($next_hops_fee_msat) {
+                               if let Some(mut available_value_contribution_msat) = htlc_maximum_msat.checked_sub($next_hops_fee_msat) {
+                                       let used_liquidity_msat = used_channel_liquidities
+                                               .get(&(short_channel_id, $src_node_id < $dest_node_id))
+                                               .map_or(0, |used_liquidity_msat| {
+                                                       available_value_contribution_msat = available_value_contribution_msat
+                                                               .saturating_sub(*used_liquidity_msat);
+                                                       *used_liquidity_msat
+                                               });
 
                                        // Routing Fragmentation Mitigation heuristic:
                                        //
@@ -861,17 +935,19 @@ where L::Target: Logger {
                                        };
                                        // Verify the liquidity offered by this channel complies to the minimal contribution.
                                        let contributes_sufficient_value = available_value_contribution_msat >= minimal_value_contribution_msat;
+                                       // Do not consider candidate hops that would exceed the maximum path length.
+                                       let path_length_to_node = $next_hops_path_length + 1;
+                                       let doesnt_exceed_max_path_length = path_length_to_node <= MAX_PATH_LENGTH_ESTIMATE;
 
                                        // Do not consider candidates that exceed the maximum total cltv expiry limit.
                                        // In order to already account for some of the privacy enhancing random CLTV
                                        // expiry delta offset we add on top later, we subtract a rough estimate
                                        // (2*MEDIAN_HOP_CLTV_EXPIRY_DELTA) here.
-                                       let max_total_cltv_expiry_delta = payment_params.max_total_cltv_expiry_delta
+                                       let max_total_cltv_expiry_delta = (payment_params.max_total_cltv_expiry_delta - final_cltv_expiry_delta)
                                                .checked_sub(2*MEDIAN_HOP_CLTV_EXPIRY_DELTA)
-                                               .unwrap_or(payment_params.max_total_cltv_expiry_delta);
+                                               .unwrap_or(payment_params.max_total_cltv_expiry_delta - final_cltv_expiry_delta);
                                        let hop_total_cltv_delta = ($next_hops_cltv_delta as u32)
-                                               .checked_add($candidate.cltv_expiry_delta())
-                                               .unwrap_or(u32::max_value());
+                                               .saturating_add($candidate.cltv_expiry_delta());
                                        let doesnt_exceed_cltv_delta_limit = hop_total_cltv_delta <= max_total_cltv_expiry_delta;
 
                                        let value_contribution_msat = cmp::min(available_value_contribution_msat, $next_hops_value_contribution);
@@ -885,14 +961,22 @@ where L::Target: Logger {
                                        let over_path_minimum_msat = amount_to_transfer_over_msat >= $candidate.htlc_minimum_msat() &&
                                                amount_to_transfer_over_msat >= $next_hops_path_htlc_minimum_msat;
 
+                                       #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains
+                                       let may_overpay_to_meet_path_minimum_msat =
+                                               ((amount_to_transfer_over_msat < $candidate.htlc_minimum_msat() &&
+                                                 recommended_value_msat > $candidate.htlc_minimum_msat()) ||
+                                                (amount_to_transfer_over_msat < $next_hops_path_htlc_minimum_msat &&
+                                                 recommended_value_msat > $next_hops_path_htlc_minimum_msat));
+
                                        // If HTLC minimum is larger than the amount we're going to transfer, we shouldn't
-                                       // bother considering this channel.
-                                       // Since we're choosing amount_to_transfer_over_msat as maximum possible, it can
-                                       // be only reduced later (not increased), so this channel should just be skipped
-                                       // as not sufficient.
-                                       if !over_path_minimum_msat && doesnt_exceed_cltv_delta_limit {
+                                       // bother considering this channel. If retrying with recommended_value_msat may
+                                       // allow us to hit the HTLC minimum limit, set htlc_minimum_limit so that we go
+                                       // around again with a higher amount.
+                                       if contributes_sufficient_value && doesnt_exceed_max_path_length &&
+                                               doesnt_exceed_cltv_delta_limit && may_overpay_to_meet_path_minimum_msat {
                                                hit_minimum_limit = true;
-                                       } else if contributes_sufficient_value && doesnt_exceed_cltv_delta_limit {
+                                       } else if contributes_sufficient_value && doesnt_exceed_max_path_length &&
+                                               doesnt_exceed_cltv_delta_limit && over_path_minimum_msat {
                                                // Note that low contribution here (limited by available_liquidity_msat)
                                                // might violate htlc_minimum_msat on the hops which are next along the
                                                // payment path (upstream to the payee). To avoid that, we recompute
@@ -978,9 +1062,16 @@ where L::Target: Logger {
                                                                }
                                                        }
 
-                                                       let path_penalty_msat = $next_hops_path_penalty_msat.checked_add(
-                                                               scorer.channel_penalty_msat(short_channel_id, amount_to_transfer_over_msat, *available_liquidity_msat,
-                                                                       &$src_node_id, &$dest_node_id)).unwrap_or_else(|| u64::max_value());
+                                                       let channel_usage = ChannelUsage {
+                                                               amount_msat: amount_to_transfer_over_msat,
+                                                               inflight_htlc_msat: used_liquidity_msat,
+                                                               effective_capacity: $candidate.effective_capacity(),
+                                                       };
+                                                       let channel_penalty_msat = scorer.channel_penalty_msat(
+                                                               short_channel_id, &$src_node_id, &$dest_node_id, channel_usage
+                                                       );
+                                                       let path_penalty_msat = $next_hops_path_penalty_msat
+                                                               .saturating_add(channel_penalty_msat);
                                                        let new_graph_node = RouteGraphNode {
                                                                node_id: $src_node_id,
                                                                lowest_fee_to_peer_through_node: total_fee_msat,
@@ -989,6 +1080,7 @@ where L::Target: Logger {
                                                                value_contribution_msat: value_contribution_msat,
                                                                path_htlc_minimum_msat,
                                                                path_penalty_msat,
+                                                               path_length_to_node,
                                                        };
 
                                                        // Update the way of reaching $src_node_id with the given short_channel_id (from $dest_node_id),
@@ -1008,11 +1100,9 @@ where L::Target: Logger {
                                                        // the fees included in $next_hops_path_htlc_minimum_msat, but also
                                                        // can't use something that may decrease on future hops.
                                                        let old_cost = cmp::max(old_entry.total_fee_msat, old_entry.path_htlc_minimum_msat)
-                                                               .checked_add(old_entry.path_penalty_msat)
-                                                               .unwrap_or_else(|| u64::max_value());
+                                                               .saturating_add(old_entry.path_penalty_msat);
                                                        let new_cost = cmp::max(total_fee_msat, path_htlc_minimum_msat)
-                                                               .checked_add(path_penalty_msat)
-                                                               .unwrap_or_else(|| u64::max_value());
+                                                               .saturating_add(path_penalty_msat);
 
                                                        if !old_entry.was_processed && new_cost < old_cost {
                                                                targets.push(new_graph_node);
@@ -1066,14 +1156,17 @@ where L::Target: Logger {
                } }
        }
 
-       let empty_node_features = NodeFeatures::empty();
+       let default_node_features = default_node_features();
+
        // Find ways (channels with destination) to reach a given node and store them
        // in the corresponding data structures (routing graph etc).
        // $fee_to_target_msat represents how much it costs to reach to this node from the payee,
        // meaning how much will be paid in fees after this node (to the best of our knowledge).
        // This data can later be helpful to optimize routing (pay lower fees).
        macro_rules! add_entries_to_cheapest_to_target_node {
-               ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr, $next_hops_path_penalty_msat: expr, $next_hops_cltv_delta: expr ) => {
+               ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr,
+                 $next_hops_path_htlc_minimum_msat: expr, $next_hops_path_penalty_msat: expr,
+                 $next_hops_cltv_delta: expr, $next_hops_path_length: expr ) => {
                        let skip_node = if let Some(elem) = dist.get_mut(&$node_id) {
                                let was_processed = elem.was_processed;
                                elem.was_processed = true;
@@ -1090,14 +1183,17 @@ where L::Target: Logger {
                                if let Some(first_channels) = first_hop_targets.get(&$node_id) {
                                        for details in first_channels {
                                                let candidate = CandidateRouteHop::FirstHop { details };
-                                               add_entry!(candidate, our_node_id, $node_id, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat, $next_hops_cltv_delta);
+                                               add_entry!(candidate, our_node_id, $node_id, $fee_to_target_msat,
+                                                       $next_hops_value_contribution,
+                                                       $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat,
+                                                       $next_hops_cltv_delta, $next_hops_path_length);
                                        }
                                }
 
                                let features = if let Some(node_info) = $node.announcement_info.as_ref() {
                                        &node_info.features
                                } else {
-                                       &empty_node_features
+                                       &default_node_features
                                };
 
                                if !features.requires_unknown_bits() {
@@ -1113,7 +1209,12 @@ where L::Target: Logger {
                                                                                        info: directed_channel.with_update().unwrap(),
                                                                                        short_channel_id: *chan_id,
                                                                                };
-                                                                               add_entry!(candidate, *source, $node_id, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat, $next_hops_cltv_delta);
+                                                                               add_entry!(candidate, *source, $node_id,
+                                                                                       $fee_to_target_msat,
+                                                                                       $next_hops_value_contribution,
+                                                                                       $next_hops_path_htlc_minimum_msat,
+                                                                                       $next_hops_path_penalty_msat,
+                                                                                       $next_hops_cltv_delta, $next_hops_path_length);
                                                                        }
                                                                }
                                                        }
@@ -1128,9 +1229,8 @@ where L::Target: Logger {
 
        // TODO: diversify by nodes (so that all paths aren't doomed if one node is offline).
        'paths_collection: loop {
-               // For every new path, start from scratch, except
-               // bookkept_channels_liquidity_available_msat, which will improve
-               // the further iterations of path finding. Also don't erase first_hop_targets.
+               // For every new path, start from scratch, except for used_channel_liquidities, which
+               // helps to avoid reusing previously selected paths in future iterations.
                targets.clear();
                dist.clear();
                hit_minimum_limit = false;
@@ -1140,8 +1240,10 @@ where L::Target: Logger {
                if let Some(first_channels) = first_hop_targets.get(&payee_node_id) {
                        for details in first_channels {
                                let candidate = CandidateRouteHop::FirstHop { details };
-                               let added = add_entry!(candidate, our_node_id, payee_node_id, 0, path_value_msat, 0, 0u64, 0);
-                               log_trace!(logger, "{} direct route to payee via SCID {}", if added { "Added" } else { "Skipped" }, candidate.short_channel_id());
+                               let added = add_entry!(candidate, our_node_id, payee_node_id, 0, path_value_msat,
+                                                                       0, 0u64, 0, 0);
+                               log_trace!(logger, "{} direct route to payee via SCID {}",
+                                               if added { "Added" } else { "Skipped" }, candidate.short_channel_id());
                        }
                }
 
@@ -1154,7 +1256,7 @@ where L::Target: Logger {
                        // If not, targets.pop() will not even let us enter the loop in step 2.
                        None => {},
                        Some(node) => {
-                               add_entries_to_cheapest_to_target_node!(node, payee_node_id, 0, path_value_msat, 0, 0u64, 0);
+                               add_entries_to_cheapest_to_target_node!(node, payee_node_id, 0, path_value_msat, 0, 0u64, 0, 0);
                        },
                }
 
@@ -1181,6 +1283,7 @@ where L::Target: Logger {
                                let mut aggregate_next_hops_path_htlc_minimum_msat: u64 = 0;
                                let mut aggregate_next_hops_path_penalty_msat: u64 = 0;
                                let mut aggregate_next_hops_cltv_delta: u32 = 0;
+                               let mut aggregate_next_hops_path_length: u8 = 0;
 
                                for (idx, (hop, prev_hop_id)) in hop_iter.zip(prev_hop_iter).enumerate() {
                                        let source = NodeId::from_pubkey(&hop.src_node_id);
@@ -1194,27 +1297,45 @@ where L::Target: Logger {
                                                        short_channel_id: hop.short_channel_id,
                                                })
                                                .unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop });
-                                       let capacity_msat = candidate.effective_capacity().as_msat();
+
+                                       if !add_entry!(candidate, source, target, aggregate_next_hops_fee_msat,
+                                                               path_value_msat, aggregate_next_hops_path_htlc_minimum_msat,
+                                                               aggregate_next_hops_path_penalty_msat,
+                                                               aggregate_next_hops_cltv_delta, aggregate_next_hops_path_length) {
+                                               // If this hop was not used then there is no use checking the preceding
+                                               // hops in the RouteHint. We can break by just searching for a direct
+                                               // channel between last checked hop and first_hop_targets.
+                                               hop_used = false;
+                                       }
+
+                                       let used_liquidity_msat = used_channel_liquidities
+                                               .get(&(hop.short_channel_id, source < target)).copied().unwrap_or(0);
+                                       let channel_usage = ChannelUsage {
+                                               amount_msat: final_value_msat + aggregate_next_hops_fee_msat,
+                                               inflight_htlc_msat: used_liquidity_msat,
+                                               effective_capacity: candidate.effective_capacity(),
+                                       };
+                                       let channel_penalty_msat = scorer.channel_penalty_msat(
+                                               hop.short_channel_id, &source, &target, channel_usage
+                                       );
                                        aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
-                                               .checked_add(scorer.channel_penalty_msat(hop.short_channel_id, final_value_msat, capacity_msat, &source, &target))
-                                               .unwrap_or_else(|| u64::max_value());
+                                               .saturating_add(channel_penalty_msat);
 
                                        aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
-                                               .checked_add(hop.cltv_expiry_delta as u32)
-                                               .unwrap_or_else(|| u32::max_value());
+                                               .saturating_add(hop.cltv_expiry_delta as u32);
 
-                                       if !add_entry!(candidate, source, target, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta) {
-                                               // If this hop was not used then there is no use checking the preceding hops
-                                               // in the RouteHint. We can break by just searching for a direct channel between
-                                               // last checked hop and first_hop_targets
-                                               hop_used = false;
-                                       }
+                                       aggregate_next_hops_path_length = aggregate_next_hops_path_length
+                                               .saturating_add(1);
 
                                        // Searching for a direct channel between last checked hop and first_hop_targets
                                        if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&prev_hop_id)) {
                                                for details in first_channels {
                                                        let candidate = CandidateRouteHop::FirstHop { details };
-                                                       add_entry!(candidate, our_node_id, NodeId::from_pubkey(&prev_hop_id), aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta);
+                                                       add_entry!(candidate, our_node_id, NodeId::from_pubkey(&prev_hop_id),
+                                                               aggregate_next_hops_fee_msat, path_value_msat,
+                                                               aggregate_next_hops_path_htlc_minimum_msat,
+                                                               aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta,
+                                                               aggregate_next_hops_path_length);
                                                }
                                        }
 
@@ -1225,7 +1346,7 @@ where L::Target: Logger {
                                        // In the next values of the iterator, the aggregate fees already reflects
                                        // the sum of value sent from payer (final_value_msat) and routing fees
                                        // for the last node in the RouteHint. We need to just add the fees to
-                                       // route through the current node so that the preceeding node (next iteration)
+                                       // route through the current node so that the preceding node (next iteration)
                                        // can use it.
                                        let hops_fee = compute_fees(aggregate_next_hops_fee_msat + final_value_msat, hop.fees)
                                                .map_or(None, |inc| inc.checked_add(aggregate_next_hops_fee_msat));
@@ -1250,7 +1371,13 @@ where L::Target: Logger {
                                                if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&hop.src_node_id)) {
                                                        for details in first_channels {
                                                                let candidate = CandidateRouteHop::FirstHop { details };
-                                                               add_entry!(candidate, our_node_id, NodeId::from_pubkey(&hop.src_node_id), aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta);
+                                                               add_entry!(candidate, our_node_id,
+                                                                       NodeId::from_pubkey(&hop.src_node_id),
+                                                                       aggregate_next_hops_fee_msat, path_value_msat,
+                                                                       aggregate_next_hops_path_htlc_minimum_msat,
+                                                                       aggregate_next_hops_path_penalty_msat,
+                                                                       aggregate_next_hops_cltv_delta,
+                                                                       aggregate_next_hops_path_length);
                                                        }
                                                }
                                        }
@@ -1273,19 +1400,19 @@ where L::Target: Logger {
                // Both these cases (and other cases except reaching recommended_value_msat) mean that
                // paths_collection will be stopped because found_new_path==false.
                // This is not necessarily a routing failure.
-               'path_construction: while let Some(RouteGraphNode { node_id, lowest_fee_to_node, total_cltv_delta, value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat, .. }) = targets.pop() {
+               'path_construction: while let Some(RouteGraphNode { node_id, lowest_fee_to_node, total_cltv_delta, value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat, path_length_to_node, .. }) = targets.pop() {
 
                        // Since we're going payee-to-payer, hitting our node as a target means we should stop
                        // traversing the graph and arrange the path out of what we found.
                        if node_id == our_node_id {
                                let mut new_entry = dist.remove(&our_node_id).unwrap();
-                               let mut ordered_hops = vec!((new_entry.clone(), NodeFeatures::empty()));
+                               let mut ordered_hops: Vec<(PathBuildingHop, NodeFeatures)> = vec!((new_entry.clone(), default_node_features.clone()));
 
                                'path_walk: loop {
                                        let mut features_set = false;
                                        if let Some(first_channels) = first_hop_targets.get(&ordered_hops.last().unwrap().0.node_id) {
                                                for details in first_channels {
-                                                       if details.short_channel_id.unwrap() == ordered_hops.last().unwrap().0.candidate.short_channel_id() {
+                                                       if details.get_outbound_payment_scid().unwrap() == ordered_hops.last().unwrap().0.candidate.short_channel_id() {
                                                                ordered_hops.last_mut().unwrap().1 = details.counterparty.features.to_context();
                                                                features_set = true;
                                                                break;
@@ -1297,7 +1424,7 @@ where L::Target: Logger {
                                                        if let Some(node_info) = node.announcement_info.as_ref() {
                                                                ordered_hops.last_mut().unwrap().1 = node_info.features.clone();
                                                        } else {
-                                                               ordered_hops.last_mut().unwrap().1 = NodeFeatures::empty();
+                                                               ordered_hops.last_mut().unwrap().1 = default_node_features.clone();
                                                        }
                                                } else {
                                                        // We can fill in features for everything except hops which were
@@ -1324,7 +1451,7 @@ where L::Target: Logger {
                                        // so that fees paid for a HTLC forwarding on the current channel are
                                        // associated with the previous channel (where they will be subtracted).
                                        ordered_hops.last_mut().unwrap().0.fee_msat = new_entry.hop_use_fee_msat;
-                                       ordered_hops.push((new_entry.clone(), NodeFeatures::empty()));
+                                       ordered_hops.push((new_entry.clone(), default_node_features.clone()));
                                }
                                ordered_hops.last_mut().unwrap().0.fee_msat = value_contribution_msat;
                                ordered_hops.last_mut().unwrap().0.hop_use_fee_msat = 0;
@@ -1351,26 +1478,30 @@ where L::Target: Logger {
                                // Remember that we used these channels so that we don't rely
                                // on the same liquidity in future paths.
                                let mut prevented_redundant_path_selection = false;
-                               for (payment_hop, _) in payment_path.hops.iter() {
-                                       let channel_liquidity_available_msat = bookkept_channels_liquidity_available_msat.get_mut(&payment_hop.candidate.short_channel_id()).unwrap();
-                                       let mut spent_on_hop_msat = value_contribution_msat;
-                                       let next_hops_fee_msat = payment_hop.next_hops_fee_msat;
-                                       spent_on_hop_msat += next_hops_fee_msat;
-                                       if spent_on_hop_msat == *channel_liquidity_available_msat {
+                               let prev_hop_iter = core::iter::once(&our_node_id)
+                                       .chain(payment_path.hops.iter().map(|(hop, _)| &hop.node_id));
+                               for (prev_hop, (hop, _)) in prev_hop_iter.zip(payment_path.hops.iter()) {
+                                       let spent_on_hop_msat = value_contribution_msat + hop.next_hops_fee_msat;
+                                       let used_liquidity_msat = used_channel_liquidities
+                                               .entry((hop.candidate.short_channel_id(), *prev_hop < hop.node_id))
+                                               .and_modify(|used_liquidity_msat| *used_liquidity_msat += spent_on_hop_msat)
+                                               .or_insert(spent_on_hop_msat);
+                                       if *used_liquidity_msat == hop.candidate.htlc_maximum_msat() {
                                                // If this path used all of this channel's available liquidity, we know
                                                // this path will not be selected again in the next loop iteration.
                                                prevented_redundant_path_selection = true;
                                        }
-                                       *channel_liquidity_available_msat -= spent_on_hop_msat;
+                                       debug_assert!(*used_liquidity_msat <= hop.candidate.htlc_maximum_msat());
                                }
                                if !prevented_redundant_path_selection {
                                        // If we weren't capped by hitting a liquidity limit on a channel in the path,
                                        // we'll probably end up picking the same path again on the next iteration.
                                        // Decrease the available liquidity of a hop in the middle of the path.
-                                       let victim_scid = payment_path.hops[(payment_path.hops.len() - 1) / 2].0.candidate.short_channel_id();
+                                       let victim_scid = payment_path.hops[(payment_path.hops.len()) / 2].0.candidate.short_channel_id();
+                                       let exhausted = u64::max_value();
                                        log_trace!(logger, "Disabling channel {} for future path building iterations to avoid duplicates.", victim_scid);
-                                       let victim_liquidity = bookkept_channels_liquidity_available_msat.get_mut(&victim_scid).unwrap();
-                                       *victim_liquidity = 0;
+                                       *used_channel_liquidities.entry((victim_scid, false)).or_default() = exhausted;
+                                       *used_channel_liquidities.entry((victim_scid, true)).or_default() = exhausted;
                                }
 
                                // Track the total amount all our collected paths allow to send so that we:
@@ -1395,7 +1526,9 @@ where L::Target: Logger {
                        match network_nodes.get(&node_id) {
                                None => {},
                                Some(node) => {
-                                       add_entries_to_cheapest_to_target_node!(node, node_id, lowest_fee_to_node, value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat, total_cltv_delta);
+                                       add_entries_to_cheapest_to_target_node!(node, node_id, lowest_fee_to_node,
+                                               value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat,
+                                               total_cltv_delta, path_length_to_node);
                                },
                        }
                }
@@ -1439,24 +1572,31 @@ where L::Target: Logger {
        }
 
        // Sort by total fees and take the best paths.
-       payment_paths.sort_by_key(|path| path.get_total_fee_paid_msat());
+       payment_paths.sort_unstable_by_key(|path| path.get_total_fee_paid_msat());
        if payment_paths.len() > 50 {
                payment_paths.truncate(50);
        }
 
        // Draw multiple sufficient routes by randomly combining the selected paths.
        let mut drawn_routes = Vec::new();
-       for i in 0..payment_paths.len() {
+       let mut prng = ChaCha20::new(random_seed_bytes, &[0u8; 12]);
+       let mut random_index_bytes = [0u8; ::core::mem::size_of::<usize>()];
+
+       let num_permutations = payment_paths.len();
+       for _ in 0..num_permutations {
                let mut cur_route = Vec::<PaymentPath>::new();
                let mut aggregate_route_value_msat = 0;
 
                // Step (6).
-               // TODO: real random shuffle
-               // Currently just starts with i_th and goes up to i-1_th in a looped way.
-               let cur_payment_paths = [&payment_paths[i..], &payment_paths[..i]].concat();
+               // Do a Fisher-Yates shuffle to create a random permutation of the payment paths
+               for cur_index in (1..payment_paths.len()).rev() {
+                       prng.process_in_place(&mut random_index_bytes);
+                       let random_index = usize::from_be_bytes(random_index_bytes).wrapping_rem(cur_index+1);
+                       payment_paths.swap(cur_index, random_index);
+               }
 
                // Step (7).
-               for payment_path in cur_payment_paths {
+               for payment_path in &payment_paths {
                        cur_route.push(payment_path.clone());
                        aggregate_route_value_msat += payment_path.get_value_msat();
                        if aggregate_route_value_msat > final_value_msat {
@@ -1466,12 +1606,16 @@ where L::Target: Logger {
                                // also makes routing more reliable.
                                let mut overpaid_value_msat = aggregate_route_value_msat - final_value_msat;
 
-                               // First, drop some expensive low-value paths entirely if possible.
-                               // Sort by value so that we drop many really-low values first, since
-                               // fewer paths is better: the payment is less likely to fail.
-                               // TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
-                               // so that the sender pays less fees overall. And also htlc_minimum_msat.
-                               cur_route.sort_by_key(|path| path.get_value_msat());
+                               // First, we drop some expensive low-value paths entirely if possible, since fewer
+                               // paths is better: the payment is less likely to fail. In order to do so, we sort
+                               // by value and fall back to total fees paid, i.e., in case of equal values we
+                               // prefer lower cost paths.
+                               cur_route.sort_unstable_by(|a, b| {
+                                       a.get_value_msat().cmp(&b.get_value_msat())
+                                               // Reverse ordering for cost, so we drop higher-cost paths first
+                                               .then_with(|| b.get_cost_msat().cmp(&a.get_cost_msat()))
+                               });
+
                                // We should make sure that at least 1 path left.
                                let mut paths_left = cur_route.len();
                                cur_route.retain(|path| {
@@ -1495,13 +1639,14 @@ where L::Target: Logger {
                                assert!(cur_route.len() > 0);
 
                                // Step (8).
-                               // Now, substract the overpaid value from the most-expensive path.
+                               // Now, subtract the overpaid value from the most-expensive path.
                                // TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
                                // so that the sender pays less fees overall. And also htlc_minimum_msat.
-                               cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.candidate.fees().proportional_millionths as u64).sum::<u64>() });
+                               cur_route.sort_unstable_by_key(|path| { path.hops.iter().map(|hop| hop.0.candidate.fees().proportional_millionths as u64).sum::<u64>() });
                                let expensive_payment_path = cur_route.first_mut().unwrap();
-                               // We already dropped all the small channels above, meaning all the
-                               // remaining channels are larger than remaining overpaid_value_msat.
+
+                               // We already dropped all the small value paths above, meaning all the
+                               // remaining paths are larger than remaining overpaid_value_msat.
                                // Thus, this can't be negative.
                                let expensive_path_new_value_msat = expensive_payment_path.get_value_msat() - overpaid_value_msat;
                                expensive_payment_path.update_value_and_recompute_fees(expensive_path_new_value_msat);
@@ -1512,8 +1657,8 @@ where L::Target: Logger {
        }
 
        // Step (9).
-       // Select the best route by lowest total fee.
-       drawn_routes.sort_by_key(|paths| paths.iter().map(|path| path.get_total_fee_paid_msat()).sum::<u64>());
+       // Select the best route by lowest total cost.
+       drawn_routes.sort_unstable_by_key(|paths| paths.iter().map(|path| path.get_cost_msat()).sum::<u64>());
        let mut selected_paths = Vec::<Vec<Result<RouteHop, LightningError>>>::new();
        for payment_path in drawn_routes.first().unwrap() {
                let mut path = payment_path.hops.iter().map(|(payment_hop, node_features)| {
@@ -1554,52 +1699,67 @@ where L::Target: Logger {
 // destination, if the remaining CLTV expiry delta exactly matches a feasible path in the network
 // graph. In order to improve privacy, this method obfuscates the CLTV expiry deltas along the
 // payment path by adding a randomized 'shadow route' offset to the final hop.
-fn add_random_cltv_offset(route: &mut Route, payment_params: &PaymentParameters, network_graph: &ReadOnlyNetworkGraph, random_seed_bytes: &[u8; 32]) {
+fn add_random_cltv_offset(route: &mut Route, payment_params: &PaymentParameters,
+       network_graph: &ReadOnlyNetworkGraph, random_seed_bytes: &[u8; 32]
+) {
        let network_channels = network_graph.channels();
        let network_nodes = network_graph.nodes();
 
        for path in route.paths.iter_mut() {
                let mut shadow_ctlv_expiry_delta_offset: u32 = 0;
 
-               // Choose the last publicly known node as the starting point for the random walk
-               if let Some(starting_hop) = path.iter().rev().find(|h| network_nodes.contains_key(&NodeId::from_pubkey(&h.pubkey))) {
-                       let mut cur_node_id = NodeId::from_pubkey(&starting_hop.pubkey);
+               // Remember the last three nodes of the random walk and avoid looping back on them.
+               // Init with the last three nodes from the actual path, if possible.
+               let mut nodes_to_avoid: [NodeId; 3] = [NodeId::from_pubkey(&path.last().unwrap().pubkey),
+                       NodeId::from_pubkey(&path.get(path.len().saturating_sub(2)).unwrap().pubkey),
+                       NodeId::from_pubkey(&path.get(path.len().saturating_sub(3)).unwrap().pubkey)];
+
+               // Choose the last publicly known node as the starting point for the random walk.
+               let mut cur_hop: Option<NodeId> = None;
+               let mut path_nonce = [0u8; 12];
+               if let Some(starting_hop) = path.iter().rev()
+                       .find(|h| network_nodes.contains_key(&NodeId::from_pubkey(&h.pubkey))) {
+                               cur_hop = Some(NodeId::from_pubkey(&starting_hop.pubkey));
+                               path_nonce.copy_from_slice(&cur_hop.unwrap().as_slice()[..12]);
+               }
+
+               // Init PRNG with the path-dependant nonce, which is static for private paths.
+               let mut prng = ChaCha20::new(random_seed_bytes, &path_nonce);
+               let mut random_path_bytes = [0u8; ::core::mem::size_of::<usize>()];
 
-                       // Init PRNG with path nonce
-                       let mut path_nonce = [0u8; 12];
-                       path_nonce.copy_from_slice(&cur_node_id.as_slice()[..12]);
-                       let mut prng = ChaCha20::new(random_seed_bytes, &path_nonce);
-                       let mut random_path_bytes = [0u8; ::core::mem::size_of::<usize>()];
+               // Pick a random path length in [1 .. 3]
+               prng.process_in_place(&mut random_path_bytes);
+               let random_walk_length = usize::from_be_bytes(random_path_bytes).wrapping_rem(3).wrapping_add(1);
 
-                       // Pick a random path length in [1 .. 3]
-                       prng.process_in_place(&mut random_path_bytes);
-                       let random_walk_length = usize::from_be_bytes(random_path_bytes).wrapping_rem(3).wrapping_add(1);
+               for random_hop in 0..random_walk_length {
+                       // If we don't find a suitable offset in the public network graph, we default to
+                       // MEDIAN_HOP_CLTV_EXPIRY_DELTA.
+                       let mut random_hop_offset = MEDIAN_HOP_CLTV_EXPIRY_DELTA;
 
-                       for _random_hop in 0..random_walk_length {
+                       if let Some(cur_node_id) = cur_hop {
                                if let Some(cur_node) = network_nodes.get(&cur_node_id) {
-                                       // Randomly choose the next hop
+                                       // Randomly choose the next unvisited hop.
                                        prng.process_in_place(&mut random_path_bytes);
-                                       if let Some(random_channel) = usize::from_be_bytes(random_path_bytes).checked_rem(cur_node.channels.len())
+                                       if let Some(random_channel) = usize::from_be_bytes(random_path_bytes)
+                                               .checked_rem(cur_node.channels.len())
                                                .and_then(|index| cur_node.channels.get(index))
                                                .and_then(|id| network_channels.get(id)) {
                                                        random_channel.as_directed_from(&cur_node_id).map(|(dir_info, next_id)| {
-                                                               dir_info.direction().map(|channel_update_info|
-                                                                       shadow_ctlv_expiry_delta_offset = shadow_ctlv_expiry_delta_offset
-                                                                               .checked_add(channel_update_info.cltv_expiry_delta.into())
-                                                                               .unwrap_or(shadow_ctlv_expiry_delta_offset));
-                                                               cur_node_id = *next_id;
+                                                               if !nodes_to_avoid.iter().any(|x| x == next_id) {
+                                                                       nodes_to_avoid[random_hop] = *next_id;
+                                                                       dir_info.direction().map(|channel_update_info| {
+                                                                               random_hop_offset = channel_update_info.cltv_expiry_delta.into();
+                                                                               cur_hop = Some(*next_id);
+                                                                       });
+                                                               }
                                                        });
                                                }
                                }
                        }
-               } else {
-                       // If the entire path is private, choose a random offset from multiples of
-                       // MEDIAN_HOP_CLTV_EXPIRY_DELTA
-                       let mut prng = ChaCha20::new(random_seed_bytes, &[0u8; 8]);
-                       let mut random_bytes = [0u8; 4];
-                       prng.process_in_place(&mut random_bytes);
-                       let random_walk_length = u32::from_be_bytes(random_bytes).wrapping_rem(3).wrapping_add(1);
-                       shadow_ctlv_expiry_delta_offset = random_walk_length * MEDIAN_HOP_CLTV_EXPIRY_DELTA;
+
+                       shadow_ctlv_expiry_delta_offset = shadow_ctlv_expiry_delta_offset
+                               .checked_add(random_hop_offset)
+                               .unwrap_or(shadow_ctlv_expiry_delta_offset);
                }
 
                // Limit the total offset to reduce the worst-case locked liquidity timevalue
@@ -1623,16 +1783,91 @@ fn add_random_cltv_offset(route: &mut Route, payment_params: &PaymentParameters,
        }
 }
 
+/// Construct a route from us (payer) to the target node (payee) via the given hops (which should
+/// exclude the payer, but include the payee). This may be useful, e.g., for probing the chosen path.
+///
+/// Re-uses logic from `find_route`, so the restrictions described there also apply here.
+pub fn build_route_from_hops<L: Deref>(
+       our_node_pubkey: &PublicKey, hops: &[PublicKey], route_params: &RouteParameters,
+       network_graph: &ReadOnlyNetworkGraph, logger: L, random_seed_bytes: &[u8; 32]
+) -> Result<Route, LightningError>
+where L::Target: Logger {
+       let mut route = build_route_from_hops_internal(
+               our_node_pubkey, hops, &route_params.payment_params, &network_graph,
+               route_params.final_value_msat, route_params.final_cltv_expiry_delta, logger, random_seed_bytes)?;
+       add_random_cltv_offset(&mut route, &route_params.payment_params, &network_graph, random_seed_bytes);
+       Ok(route)
+}
+
+fn build_route_from_hops_internal<L: Deref>(
+       our_node_pubkey: &PublicKey, hops: &[PublicKey], payment_params: &PaymentParameters,
+       network_graph: &ReadOnlyNetworkGraph, final_value_msat: u64, final_cltv_expiry_delta: u32,
+       logger: L, random_seed_bytes: &[u8; 32]
+) -> Result<Route, LightningError> where L::Target: Logger {
+
+       struct HopScorer {
+               our_node_id: NodeId,
+               hop_ids: [Option<NodeId>; MAX_PATH_LENGTH_ESTIMATE as usize],
+       }
+
+       impl Score for HopScorer {
+               fn channel_penalty_msat(&self, _short_channel_id: u64, source: &NodeId, target: &NodeId,
+                       _usage: ChannelUsage) -> u64
+               {
+                       let mut cur_id = self.our_node_id;
+                       for i in 0..self.hop_ids.len() {
+                               if let Some(next_id) = self.hop_ids[i] {
+                                       if cur_id == *source && next_id == *target {
+                                               return 0;
+                                       }
+                                       cur_id = next_id;
+                               } else {
+                                       break;
+                               }
+                       }
+                       u64::max_value()
+               }
+
+               fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
+
+               fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
+       }
+
+       impl<'a> Writeable for HopScorer {
+               #[inline]
+               fn write<W: Writer>(&self, _w: &mut W) -> Result<(), io::Error> {
+                       unreachable!();
+               }
+       }
+
+       if hops.len() > MAX_PATH_LENGTH_ESTIMATE.into() {
+               return Err(LightningError{err: "Cannot build a route exceeding the maximum path length.".to_owned(), action: ErrorAction::IgnoreError});
+       }
+
+       let our_node_id = NodeId::from_pubkey(our_node_pubkey);
+       let mut hop_ids = [None; MAX_PATH_LENGTH_ESTIMATE as usize];
+       for i in 0..hops.len() {
+               hop_ids[i] = Some(NodeId::from_pubkey(&hops[i]));
+       }
+
+       let scorer = HopScorer { our_node_id, hop_ids };
+
+       get_route(our_node_pubkey, payment_params, network_graph, None, final_value_msat,
+               final_cltv_expiry_delta, logger, &scorer, random_seed_bytes)
+}
+
 #[cfg(test)]
 mod tests {
-       use routing::network_graph::{NetworkGraph, NetGraphMsgHandler, NodeId};
-       use routing::router::{get_route, add_random_cltv_offset, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees, DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA};
-       use routing::scoring::Score;
+       use routing::gossip::{NetworkGraph, P2PGossipSync, NodeId};
+       use routing::router::{get_route, build_route_from_hops_internal, add_random_cltv_offset, default_node_features,
+               PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees,
+               DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE};
+       use routing::scoring::{ChannelUsage, Score};
        use chain::transaction::OutPoint;
        use chain::keysinterface::KeysInterface;
        use ln::features::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
        use ln::msgs::{ErrorAction, LightningError, OptionalField, UnsignedChannelAnnouncement, ChannelAnnouncement, RoutingMessageHandler,
-          NodeAnnouncement, UnsignedNodeAnnouncement, ChannelUpdate, UnsignedChannelUpdate};
+               NodeAnnouncement, UnsignedNodeAnnouncement, ChannelUpdate, UnsignedChannelUpdate};
        use ln::channelmanager;
        use util::test_utils;
        use util::chacha20::ChaCha20;
@@ -1650,7 +1885,7 @@ mod tests {
 
        use hex;
 
-       use bitcoin::secp256k1::key::{PublicKey,SecretKey};
+       use bitcoin::secp256k1::{PublicKey,SecretKey};
        use bitcoin::secp256k1::{Secp256k1, All};
 
        use prelude::*;
@@ -1665,25 +1900,33 @@ mod tests {
                                node_id,
                                unspendable_punishment_reserve: 0,
                                forwarding_info: None,
+                               outbound_htlc_minimum_msat: None,
+                               outbound_htlc_maximum_msat: None,
                        },
                        funding_txo: Some(OutPoint { txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0 }),
+                       channel_type: None,
                        short_channel_id,
+                       outbound_scid_alias: None,
+                       inbound_scid_alias: None,
                        channel_value_satoshis: 0,
                        user_channel_id: 0,
                        balance_msat: 0,
                        outbound_capacity_msat,
+                       next_outbound_htlc_limit_msat: outbound_capacity_msat,
                        inbound_capacity_msat: 42,
                        unspendable_punishment_reserve: None,
                        confirmations_required: None,
                        force_close_spend_delay: None,
-                       is_outbound: true, is_funding_locked: true,
+                       is_outbound: true, is_channel_ready: true,
                        is_usable: true, is_public: true,
+                       inbound_htlc_minimum_msat: None,
+                       inbound_htlc_maximum_msat: None,
                }
        }
 
        // Using the same keys for LN and BTC ids
        fn add_channel(
-               net_graph_msg_handler: &NetGraphMsgHandler<Arc<NetworkGraph>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
+               gossip_sync: &P2PGossipSync<Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
                secp_ctx: &Secp256k1<All>, node_1_privkey: &SecretKey, node_2_privkey: &SecretKey, features: ChannelFeatures, short_channel_id: u64
        ) {
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
@@ -1702,36 +1945,36 @@ mod tests {
 
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
-                       node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
-                       node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
-                       bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
-                       bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
+                       node_signature_1: secp_ctx.sign_ecdsa(&msghash, node_1_privkey),
+                       node_signature_2: secp_ctx.sign_ecdsa(&msghash, node_2_privkey),
+                       bitcoin_signature_1: secp_ctx.sign_ecdsa(&msghash, node_1_privkey),
+                       bitcoin_signature_2: secp_ctx.sign_ecdsa(&msghash, node_2_privkey),
                        contents: unsigned_announcement.clone(),
                };
-               match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
+               match gossip_sync.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        _ => panic!()
                };
        }
 
        fn update_channel(
-               net_graph_msg_handler: &NetGraphMsgHandler<Arc<NetworkGraph>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
+               gossip_sync: &P2PGossipSync<Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
                secp_ctx: &Secp256k1<All>, node_privkey: &SecretKey, update: UnsignedChannelUpdate
        ) {
                let msghash = hash_to_message!(&Sha256dHash::hash(&update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
-                       signature: secp_ctx.sign(&msghash, node_privkey),
+                       signature: secp_ctx.sign_ecdsa(&msghash, node_privkey),
                        contents: update.clone()
                };
 
-               match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
+               match gossip_sync.handle_channel_update(&valid_channel_update) {
                        Ok(res) => assert!(res),
                        Err(_) => panic!()
                };
        }
 
        fn add_or_update_node(
-               net_graph_msg_handler: &NetGraphMsgHandler<Arc<NetworkGraph>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
+               gossip_sync: &P2PGossipSync<Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
                secp_ctx: &Secp256k1<All>, node_privkey: &SecretKey, features: NodeFeatures, timestamp: u32
        ) {
                let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);
@@ -1747,18 +1990,18 @@ mod tests {
                };
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = NodeAnnouncement {
-                       signature: secp_ctx.sign(&msghash, node_privkey),
+                       signature: secp_ctx.sign_ecdsa(&msghash, node_privkey),
                        contents: unsigned_announcement.clone()
                };
 
-               match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
+               match gossip_sync.handle_node_announcement(&valid_announcement) {
                        Ok(_) => (),
                        Err(_) => panic!()
                };
        }
 
        fn get_nodes(secp_ctx: &Secp256k1<All>) -> (SecretKey, PublicKey, Vec<SecretKey>, Vec<PublicKey>) {
-               let privkeys: Vec<SecretKey> = (2..10).map(|i| {
+               let privkeys: Vec<SecretKey> = (2..22).map(|i| {
                        SecretKey::from_slice(&hex::decode(format!("{:02x}", i).repeat(32)).unwrap()[..]).unwrap()
                }).collect();
 
@@ -1785,18 +2028,71 @@ mod tests {
                }
        }
 
+       fn build_line_graph() -> (
+               Secp256k1<All>, sync::Arc<NetworkGraph<Arc<test_utils::TestLogger>>>,
+               P2PGossipSync<sync::Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, sync::Arc<test_utils::TestChainSource>, sync::Arc<test_utils::TestLogger>>,
+               sync::Arc<test_utils::TestChainSource>, sync::Arc<test_utils::TestLogger>,
+       ) {
+               let secp_ctx = Secp256k1::new();
+               let logger = Arc::new(test_utils::TestLogger::new());
+               let chain_monitor = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let network_graph = Arc::new(NetworkGraph::new(genesis_hash, Arc::clone(&logger)));
+               let gossip_sync = P2PGossipSync::new(Arc::clone(&network_graph), None, Arc::clone(&logger));
+
+               // Build network from our_id to node 19:
+               // our_id -1(1)2- node0 -1(2)2- node1 - ... - node19
+               let (our_privkey, _, privkeys, _) = get_nodes(&secp_ctx);
+
+               for (idx, (cur_privkey, next_privkey)) in core::iter::once(&our_privkey)
+                       .chain(privkeys.iter()).zip(privkeys.iter()).enumerate() {
+                       let cur_short_channel_id = (idx as u64) + 1;
+                       add_channel(&gossip_sync, &secp_ctx, &cur_privkey, &next_privkey,
+                               ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), cur_short_channel_id);
+                       update_channel(&gossip_sync, &secp_ctx, &cur_privkey, UnsignedChannelUpdate {
+                               chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+                               short_channel_id: cur_short_channel_id,
+                               timestamp: idx as u32,
+                               flags: 0,
+                               cltv_expiry_delta: 0,
+                               htlc_minimum_msat: 0,
+                               htlc_maximum_msat: OptionalField::Absent,
+                               fee_base_msat: 0,
+                               fee_proportional_millionths: 0,
+                               excess_data: Vec::new()
+                       });
+                       update_channel(&gossip_sync, &secp_ctx, &next_privkey, UnsignedChannelUpdate {
+                               chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+                               short_channel_id: cur_short_channel_id,
+                               timestamp: (idx as u32)+1,
+                               flags: 1,
+                               cltv_expiry_delta: 0,
+                               htlc_minimum_msat: 0,
+                               htlc_maximum_msat: OptionalField::Absent,
+                               fee_base_msat: 0,
+                               fee_proportional_millionths: 0,
+                               excess_data: Vec::new()
+                       });
+                       add_or_update_node(&gossip_sync, &secp_ctx, next_privkey,
+                               NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
+               }
+
+               (secp_ctx, network_graph, gossip_sync, chain_monitor, logger)
+       }
+
        fn build_graph() -> (
                Secp256k1<All>,
-               sync::Arc<NetworkGraph>,
-               NetGraphMsgHandler<sync::Arc<NetworkGraph>, sync::Arc<test_utils::TestChainSource>, sync::Arc<crate::util::test_utils::TestLogger>>,
+               sync::Arc<NetworkGraph<Arc<test_utils::TestLogger>>>,
+               P2PGossipSync<sync::Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, sync::Arc<test_utils::TestChainSource>, sync::Arc<test_utils::TestLogger>>,
                sync::Arc<test_utils::TestChainSource>,
                sync::Arc<test_utils::TestLogger>,
        ) {
                let secp_ctx = Secp256k1::new();
                let logger = Arc::new(test_utils::TestLogger::new());
                let chain_monitor = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
-               let network_graph = Arc::new(NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()));
-               let net_graph_msg_handler = NetGraphMsgHandler::new(Arc::clone(&network_graph), None, Arc::clone(&logger));
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let network_graph = Arc::new(NetworkGraph::new(genesis_hash, Arc::clone(&logger)));
+               let gossip_sync = P2PGossipSync::new(Arc::clone(&network_graph), None, Arc::clone(&logger));
                // Build network from our_id to node6:
                //
                //        -1(1)2-  node0  -1(3)2-
@@ -1858,8 +2154,8 @@ mod tests {
 
                let (our_privkey, _, privkeys, _) = get_nodes(&secp_ctx);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[0], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &our_privkey, &privkeys[0], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 1,
@@ -1872,10 +2168,10 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[0], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[0], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2);
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 1,
@@ -1887,7 +2183,7 @@ mod tests {
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 1,
@@ -1900,10 +2196,10 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[7], ChannelFeatures::from_le_bytes(id_to_feature_flags(12)), 12);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &our_privkey, &privkeys[7], ChannelFeatures::from_le_bytes(id_to_feature_flags(12)), 12);
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 1,
@@ -1915,7 +2211,7 @@ mod tests {
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 1,
@@ -1928,10 +2224,10 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[7], NodeFeatures::from_le_bytes(id_to_feature_flags(8)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[7], NodeFeatures::from_le_bytes(id_to_feature_flags(8)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[0], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 1,
@@ -1943,7 +2239,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 1,
@@ -1956,8 +2252,8 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[1], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 1,
@@ -1969,7 +2265,7 @@ mod tests {
                        fee_proportional_millionths: 1000000,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 1,
@@ -1982,8 +2278,8 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(13)), 13);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[7], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(13)), 13);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 1,
@@ -1995,7 +2291,7 @@ mod tests {
                        fee_proportional_millionths: 2000000,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 1,
@@ -2008,10 +2304,10 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 1,
@@ -2023,7 +2319,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 1,
@@ -2036,8 +2332,8 @@ mod tests {
                        excess_data: Vec::new(),
                });
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(11)), 11);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(11)), 11);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 11,
                        timestamp: 1,
@@ -2049,7 +2345,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[3], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 11,
                        timestamp: 1,
@@ -2062,12 +2358,12 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(5)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(5)), 0);
 
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[5], ChannelFeatures::from_le_bytes(id_to_feature_flags(7)), 7);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[2], &privkeys[5], ChannelFeatures::from_le_bytes(id_to_feature_flags(7)), 7);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 1,
@@ -2079,7 +2375,7 @@ mod tests {
                        fee_proportional_millionths: 1000000,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[5], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[5], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 1,
@@ -2092,9 +2388,9 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[5], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[5], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0);
 
-               (secp_ctx, network_graph, net_graph_msg_handler, chain_monitor, logger)
+               (secp_ctx, network_graph, gossip_sync, chain_monitor, logger)
        }
 
        #[test]
@@ -2154,7 +2450,7 @@ mod tests {
 
        #[test]
        fn htlc_minimum_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
                let scorer = test_utils::TestScorer::with_penalty(0);
@@ -2164,7 +2460,7 @@ mod tests {
                // Simple route to 2 via 1
 
                // Disable other paths
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -2176,7 +2472,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -2188,7 +2484,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -2200,7 +2496,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 2,
@@ -2212,7 +2508,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 2,
@@ -2227,7 +2523,7 @@ mod tests {
 
                // Check against amount_to_transfer_over_msat.
                // Set minimal HTLC of 200_000_000 msat.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 3,
@@ -2242,7 +2538,7 @@ mod tests {
 
                // Second hop only allows to forward 199_999_999 at most, thus not allowing the first hop to
                // be used.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 3,
@@ -2261,7 +2557,7 @@ mod tests {
                } else { panic!(); }
 
                // Lift the restriction on the first hop.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 4,
@@ -2281,7 +2577,7 @@ mod tests {
 
        #[test]
        fn htlc_minimum_overpay_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
                let scorer = test_utils::TestScorer::with_penalty(0);
@@ -2291,7 +2587,7 @@ mod tests {
                // A route to node#2 via two paths.
                // One path allows transferring 35-40 sats, another one also allows 35-40 sats.
                // Thus, they can't send 60 without overpaying.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -2303,7 +2599,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 3,
@@ -2317,7 +2613,7 @@ mod tests {
                });
 
                // Make 0 fee.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -2329,7 +2625,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 2,
@@ -2343,7 +2639,7 @@ mod tests {
                });
 
                // Disable other paths
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 3,
@@ -2364,7 +2660,7 @@ mod tests {
 
                // Now, test that if there are 2 paths, a "cheaper" by fee path wouldn't be prioritized
                // while taking even more fee to match htlc_minimum_msat.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 4,
@@ -2376,7 +2672,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 3,
@@ -2388,7 +2684,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 4,
@@ -2419,7 +2715,7 @@ mod tests {
 
        #[test]
        fn disable_channels_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
                let scorer = test_utils::TestScorer::with_penalty(0);
@@ -2427,7 +2723,7 @@ mod tests {
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
 
                // // Disable channels 4 and 12 by flags=2
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 2,
@@ -2439,7 +2735,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -2479,7 +2775,7 @@ mod tests {
 
        #[test]
        fn disable_node_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
                let scorer = test_utils::TestScorer::with_penalty(0);
@@ -2487,10 +2783,11 @@ mod tests {
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
 
                // Disable nodes 1, 2, and 8 by requiring unknown feature bits
-               let unknown_features = NodeFeatures::known().set_unknown_feature_required();
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[0], unknown_features.clone(), 1);
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], unknown_features.clone(), 1);
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[7], unknown_features.clone(), 1);
+               let mut unknown_features = NodeFeatures::known();
+               unknown_features.set_unknown_feature_required();
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[0], unknown_features.clone(), 1);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[1], unknown_features.clone(), 1);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[7], unknown_features.clone(), 1);
 
                // If all nodes require some features we don't understand, route should fail
                if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 100, 42, Arc::clone(&logger), &scorer, &random_seed_bytes) {
@@ -2724,7 +3021,7 @@ mod tests {
                assert_eq!(route.paths[0][4].short_channel_id, 8);
                assert_eq!(route.paths[0][4].fee_msat, 100);
                assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
        }
 
@@ -2800,7 +3097,7 @@ mod tests {
                assert_eq!(route.paths[0][4].short_channel_id, 8);
                assert_eq!(route.paths[0][4].fee_msat, 100);
                assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
        }
 
@@ -2833,7 +3130,7 @@ mod tests {
 
        #[test]
        fn multi_hint_last_hops_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let last_hops = multi_hop_last_hops_hint([nodes[2], nodes[3]]);
                let payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(last_hops.clone());
@@ -2844,7 +3141,7 @@ mod tests {
                // Test shows that multiple hop hints are considered.
 
                // Disabling channels 6 & 7 by flags=2
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 2,
@@ -2856,7 +3153,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 2,
@@ -2897,13 +3194,13 @@ mod tests {
                assert_eq!(route.paths[0][3].short_channel_id, last_hops[0].0[1].short_channel_id);
                assert_eq!(route.paths[0][3].fee_msat, 100);
                assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][3].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
        }
 
        #[test]
        fn private_multi_hint_last_hops_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
 
                let non_announced_privkey = SecretKey::from_slice(&hex::decode(format!("{:02x}", 0xf0).repeat(32)).unwrap()[..]).unwrap();
@@ -2916,7 +3213,7 @@ mod tests {
                // Test shows that multiple hop hints are considered.
 
                // Disabling channels 6 & 7 by flags=2
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 2,
@@ -2928,7 +3225,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 2,
@@ -2962,14 +3259,14 @@ mod tests {
                assert_eq!(route.paths[0][2].short_channel_id, last_hops[0].0[0].short_channel_id);
                assert_eq!(route.paths[0][2].fee_msat, 0);
                assert_eq!(route.paths[0][2].cltv_expiry_delta, 129);
-               assert_eq!(route.paths[0][2].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][2].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][2].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
 
                assert_eq!(route.paths[0][3].pubkey, nodes[6]);
                assert_eq!(route.paths[0][3].short_channel_id, last_hops[0].0[1].short_channel_id);
                assert_eq!(route.paths[0][3].fee_msat, 100);
                assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][3].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
        }
 
@@ -3060,7 +3357,7 @@ mod tests {
                assert_eq!(route.paths[0][4].short_channel_id, 8);
                assert_eq!(route.paths[0][4].fee_msat, 100);
                assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
        }
 
@@ -3090,7 +3387,7 @@ mod tests {
                assert_eq!(route.paths[0][1].short_channel_id, 8);
                assert_eq!(route.paths[0][1].fee_msat, 100);
                assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][1].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][1].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][1].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
 
                last_hops[0].0[0].fees.base_msat = 1000;
@@ -3127,7 +3424,7 @@ mod tests {
                assert_eq!(route.paths[0][3].short_channel_id, 10);
                assert_eq!(route.paths[0][3].fee_msat, 100);
                assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][3].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
 
                // ...but still use 8 for larger payments as 6 has a variable feerate
@@ -3168,7 +3465,7 @@ mod tests {
                assert_eq!(route.paths[0][4].short_channel_id, 8);
                assert_eq!(route.paths[0][4].fee_msat, 2000);
                assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
        }
 
@@ -3194,8 +3491,12 @@ mod tests {
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
-               get_route(&source_node_id, &payment_params, &NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()).read_only(),
-                               Some(&our_chans.iter().collect::<Vec<_>>()), route_val, 42, &test_utils::TestLogger::new(), &scorer, &random_seed_bytes)
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let logger = test_utils::TestLogger::new();
+               let network_graph = NetworkGraph::new(genesis_hash, &logger);
+               let route = get_route(&source_node_id, &payment_params, &network_graph.read_only(),
+                               Some(&our_chans.iter().collect::<Vec<_>>()), route_val, 42, &logger, &scorer, &random_seed_bytes);
+               route
        }
 
        #[test]
@@ -3220,7 +3521,7 @@ mod tests {
                assert_eq!(route.paths[0][1].short_channel_id, 8);
                assert_eq!(route.paths[0][1].fee_msat, 1000000);
                assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
-               assert_eq!(route.paths[0][1].node_features.le_flags(), &[0; 0]); // We dont pass flags in from invoices yet
+               assert_eq!(route.paths[0][1].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
                assert_eq!(route.paths[0][1].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly
        }
 
@@ -3246,7 +3547,7 @@ mod tests {
        fn available_amount_while_routing_test() {
                // Tests whether we choose the correct available channel amount while routing.
 
-               let (secp_ctx, network_graph, mut net_graph_msg_handler, chain_monitor, logger) = build_graph();
+               let (secp_ctx, network_graph, mut gossip_sync, chain_monitor, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -3257,7 +3558,7 @@ mod tests {
                // our node to node2 via node0: channels {1, 3}.
 
                // First disable all other paths.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -3269,7 +3570,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -3284,7 +3585,7 @@ mod tests {
 
                // Make the first channel (#1) very permissive,
                // and we will be testing all limits on the second channel.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -3299,7 +3600,7 @@ mod tests {
 
                // First, let's see if routing works if we have absolutely no idea about the available amount.
                // In this case, it should be set to 250_000 sats.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -3330,9 +3631,9 @@ mod tests {
                        assert_eq!(path.last().unwrap().fee_msat, 250_000_000);
                }
 
-               // Check that setting outbound_capacity_msat in first_hops limits the channels.
+               // Check that setting next_outbound_htlc_limit_msat in first_hops limits the channels.
                // Disable channel #1 and use another first hop.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 3,
@@ -3345,7 +3646,7 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               // Now, limit the first_hop by the outbound_capacity_msat of 200_000 sats.
+               // Now, limit the first_hop by the next_outbound_htlc_limit_msat of 200_000 sats.
                let our_chans = vec![get_channel_details(Some(42), nodes[0].clone(), InitFeatures::from_le_bytes(vec![0b11]), 200_000_000)];
 
                {
@@ -3367,7 +3668,7 @@ mod tests {
                }
 
                // Enable channel #1 back.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 4,
@@ -3382,7 +3683,7 @@ mod tests {
 
 
                // Now let's see if routing works if we know only htlc_maximum_msat.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 3,
@@ -3417,7 +3718,7 @@ mod tests {
 
                // We can't change UTXO capacity on the fly, so we'll disable
                // the existing channel and add another one with the capacity we need.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 4,
@@ -3437,10 +3738,10 @@ mod tests {
                .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
 
                *chain_monitor.utxo_ret.lock().unwrap() = Ok(TxOut { value: 15, script_pubkey: good_script.clone() });
-               net_graph_msg_handler.add_chain_access(Some(chain_monitor));
+               gossip_sync.add_chain_access(Some(chain_monitor));
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 333);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[0], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 333);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 333,
                        timestamp: 1,
@@ -3452,7 +3753,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 333,
                        timestamp: 1,
@@ -3484,7 +3785,7 @@ mod tests {
                }
 
                // Now let's see if routing chooses htlc_maximum_msat over UTXO capacity.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 333,
                        timestamp: 6,
@@ -3520,7 +3821,7 @@ mod tests {
        fn available_liquidity_last_hop_test() {
                // Check that available liquidity properly limits the path even when only
                // one of the latter hops is limited.
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -3532,7 +3833,7 @@ mod tests {
                // Total capacity: 50 sats.
 
                // Disable other potential paths.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -3544,7 +3845,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 2,
@@ -3559,7 +3860,7 @@ mod tests {
 
                // Limit capacities
 
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -3571,7 +3872,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -3584,7 +3885,7 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 2,
@@ -3596,7 +3897,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 11,
                        timestamp: 2,
@@ -3645,7 +3946,7 @@ mod tests {
 
        #[test]
        fn ignore_fee_first_hop_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -3653,7 +3954,7 @@ mod tests {
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
 
                // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50).
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -3665,7 +3966,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -3693,7 +3994,7 @@ mod tests {
 
        #[test]
        fn simple_mpp_route_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -3709,7 +4010,7 @@ mod tests {
                // Their aggregate capacity will be 50 + 60 + 180 = 290 sats.
 
                // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50).
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -3721,7 +4022,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -3736,7 +4037,7 @@ mod tests {
 
                // Path via node7 is channels {12, 13}. Limit them to 60 and 60 sats
                // (total limit 60).
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -3748,7 +4049,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -3763,7 +4064,7 @@ mod tests {
 
                // Path via node1 is channels {2, 4}. Limit them to 200 and 180 sats
                // (total capacity 180 sats).
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -3775,7 +4076,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 2,
@@ -3826,7 +4127,7 @@ mod tests {
 
        #[test]
        fn long_mpp_route_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -3841,7 +4142,7 @@ mod tests {
                // are used twice will have 200 sats capacity.
 
                // Disable other potential paths.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -3853,7 +4154,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 2,
@@ -3867,7 +4168,7 @@ mod tests {
                });
 
                // Path via {node0, node2} is channels {1, 3, 5}.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -3879,7 +4180,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -3893,8 +4194,8 @@ mod tests {
                });
 
                // Capacity of 200 sats because this channel will be used by 3rd path as well.
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 5,
                        timestamp: 2,
@@ -3910,7 +4211,7 @@ mod tests {
                // Path via {node7, node2, node4} is channels {12, 13, 6, 11}.
                // Add 100 sats to the capacities of {12, 13}, because these channels
                // are also used for 3rd path. 100 sats for the rest. Total capacity: 100 sats.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -3922,7 +4223,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -3935,7 +4236,7 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 2,
@@ -3947,7 +4248,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 11,
                        timestamp: 2,
@@ -3990,7 +4291,7 @@ mod tests {
 
        #[test]
        fn mpp_cheaper_route_test() {
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -4009,7 +4310,7 @@ mod tests {
                // are used twice will have 200 sats capacity.
 
                // Disable other potential paths.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -4021,7 +4322,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 2,
@@ -4035,7 +4336,7 @@ mod tests {
                });
 
                // Path via {node0, node2} is channels {1, 3, 5}.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -4047,7 +4348,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -4061,8 +4362,8 @@ mod tests {
                });
 
                // Capacity of 200 sats because this channel will be used by 3rd path as well.
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 5,
                        timestamp: 2,
@@ -4078,7 +4379,7 @@ mod tests {
                // Path via {node7, node2, node4} is channels {12, 13, 6, 11}.
                // Add 100 sats to the capacities of {12, 13}, because these channels
                // are also used for 3rd path. 100 sats for the rest. Total capacity: 100 sats.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -4090,7 +4391,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -4103,7 +4404,7 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 2,
@@ -4115,7 +4416,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 11,
                        timestamp: 2,
@@ -4159,7 +4460,7 @@ mod tests {
                // This test makes sure that MPP algorithm properly takes into account
                // fees charged on the channels, by making the fees impactful:
                // if the fee is not properly accounted for, the behavior is different.
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -4176,7 +4477,7 @@ mod tests {
                // It's fine to ignore this concern for now.
 
                // Disable other potential paths.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -4189,7 +4490,7 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 7,
                        timestamp: 2,
@@ -4203,7 +4504,7 @@ mod tests {
                });
 
                // Path via {node0, node2} is channels {1, 3, 5}.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -4215,7 +4516,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -4228,8 +4529,8 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 5,
                        timestamp: 2,
@@ -4252,7 +4553,7 @@ mod tests {
                // - channel 12 capacity is 250 sats
                // - fee for channel 6 is 150 sats
                // Let's test this by enforcing these 2 conditions and removing other limits.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -4264,7 +4565,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -4277,7 +4578,7 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 2,
@@ -4289,7 +4590,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 11,
                        timestamp: 2,
@@ -4340,7 +4641,7 @@ mod tests {
                // to only have the remaining to-collect amount in available liquidity.
                //
                // This bug appeared in production in some specific channel configurations.
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -4360,7 +4661,7 @@ mod tests {
                // would first use the no-fee route and then fail to find a path along the second route as
                // we think we can only send up to 1 additional sat over the last-hop but refuse to as its
                // under 5% of our payment amount.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -4372,7 +4673,7 @@ mod tests {
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -4384,7 +4685,7 @@ mod tests {
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 2,
@@ -4396,7 +4697,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -4430,7 +4731,7 @@ mod tests {
        fn drop_lowest_channel_mpp_route_test() {
                // This test checks that low-capacity channel is dropped when after
                // path finding we realize that we found more capacity than we need.
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -4447,7 +4748,7 @@ mod tests {
                // Their aggregate capacity will be 50 + 60 + 20 = 130 sats.
 
                // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 2,
@@ -4459,7 +4760,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 2,
@@ -4473,7 +4774,7 @@ mod tests {
                });
 
                // Path via node7 is channels {12, 13}. Limit them to 60 and 60 sats (total limit 60);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -4485,7 +4786,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 13,
                        timestamp: 2,
@@ -4499,7 +4800,7 @@ mod tests {
                });
 
                // Path via node1 is channels {2, 4}. Limit them to 20 and 20 sats (total capacity 20 sats).
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -4511,7 +4812,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 2,
@@ -4587,17 +4888,18 @@ mod tests {
                // payment) htlc_minimum_msat. In the original algorithm, this resulted in node4's
                // "previous hop" being set to node 3, creating a loop in the path.
                let secp_ctx = Secp256k1::new();
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
                let logger = Arc::new(test_utils::TestLogger::new());
-               let network = Arc::new(NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()));
-               let net_graph_msg_handler = NetGraphMsgHandler::new(Arc::clone(&network), None, Arc::clone(&logger));
+               let network = Arc::new(NetworkGraph::new(genesis_hash, Arc::clone(&logger)));
+               let gossip_sync = P2PGossipSync::new(Arc::clone(&network), None, Arc::clone(&logger));
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
                let payment_params = PaymentParameters::from_node_id(nodes[6]);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 6,
                        timestamp: 1,
@@ -4609,10 +4911,10 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[1], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 5,
                        timestamp: 1,
@@ -4624,10 +4926,10 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 1,
@@ -4639,10 +4941,10 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[3], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[3], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 3,
                        timestamp: 1,
@@ -4654,10 +4956,10 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0);
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 1,
@@ -4670,8 +4972,8 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[6], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1);
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+               add_channel(&gossip_sync, &secp_ctx, &privkeys[4], &privkeys[6], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1);
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 1,
                        timestamp: 1,
@@ -4683,7 +4985,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[6], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0);
+               add_or_update_node(&gossip_sync, &secp_ctx, &privkeys[6], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0);
 
                {
                        // Now ensure the route flows simply over nodes 1 and 4 to 6.
@@ -4720,7 +5022,7 @@ mod tests {
                // Test that if, while walking the graph, we find a hop that has exactly enough liquidity
                // for us, including later hop fees, we take it. In the first version of our MPP algorithm
                // we calculated fees on a higher value, resulting in us ignoring such paths.
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, _, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -4729,7 +5031,7 @@ mod tests {
 
                // We modify the graph to set the htlc_maximum of channel 2 to below the value we wish to
                // send.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -4742,7 +5044,7 @@ mod tests {
                        excess_data: Vec::new()
                });
 
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 12,
                        timestamp: 2,
@@ -4784,7 +5086,7 @@ mod tests {
                // htlc_maximum_msat, we don't end up undershooting a later htlc_minimum_msat. In the
                // initial version of MPP we'd accept such routes but reject them while recalculating fees,
                // resulting in us thinking there is no possible path, even if other paths exist.
-               let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let scorer = test_utils::TestScorer::with_penalty(0);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -4794,7 +5096,7 @@ mod tests {
                // We modify the graph to set the htlc_minimum of channel 2 and 4 as needed - channel 2
                // gets an htlc_maximum_msat of 80_000 and channel 4 an htlc_minimum_msat of 90_000. We
                // then try to send 90_000.
-               update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 2,
                        timestamp: 2,
@@ -4806,7 +5108,7 @@ mod tests {
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
                });
-               update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 4,
                        timestamp: 2,
@@ -4853,8 +5155,9 @@ mod tests {
                // route over multiple channels with the same first hop.
                let secp_ctx = Secp256k1::new();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
                let logger = Arc::new(test_utils::TestLogger::new());
-               let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
+               let network_graph = NetworkGraph::new(genesis_hash, Arc::clone(&logger));
                let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[0]).with_features(InvoiceFeatures::known());
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
@@ -4889,6 +5192,32 @@ mod tests {
                        assert_eq!(route.paths[1][0].short_channel_id, 2);
                        assert_eq!(route.paths[1][0].fee_msat, 50_000);
                }
+
+               {
+                       // If we have a bunch of outbound channels to the same node, where most are not
+                       // sufficient to pay the full payment, but one is, we should default to just using the
+                       // one single channel that has sufficient balance, avoiding MPP.
+                       //
+                       // If we have several options above the 3xpayment value threshold, we should pick the
+                       // smallest of them, avoiding further fragmenting our available outbound balance to
+                       // this node.
+                       let route = get_route(&our_id, &payment_params, &network_graph.read_only(), Some(&[
+                               &get_channel_details(Some(2), nodes[0], InitFeatures::known(), 50_000),
+                               &get_channel_details(Some(3), nodes[0], InitFeatures::known(), 50_000),
+                               &get_channel_details(Some(5), nodes[0], InitFeatures::known(), 50_000),
+                               &get_channel_details(Some(6), nodes[0], InitFeatures::known(), 300_000),
+                               &get_channel_details(Some(7), nodes[0], InitFeatures::known(), 50_000),
+                               &get_channel_details(Some(8), nodes[0], InitFeatures::known(), 50_000),
+                               &get_channel_details(Some(9), nodes[0], InitFeatures::known(), 50_000),
+                               &get_channel_details(Some(4), nodes[0], InitFeatures::known(), 1_000_000),
+                       ]), 100_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
+                       assert_eq!(route.paths.len(), 1);
+                       assert_eq!(route.paths[0].len(), 1);
+
+                       assert_eq!(route.paths[0][0].pubkey, nodes[0]);
+                       assert_eq!(route.paths[0][0].short_channel_id, 6);
+                       assert_eq!(route.paths[0][0].fee_msat, 100_000);
+               }
        }
 
        #[test]
@@ -4934,7 +5263,7 @@ mod tests {
                fn write<W: Writer>(&self, _w: &mut W) -> Result<(), ::io::Error> { unimplemented!() }
        }
        impl Score for BadChannelScorer {
-               fn channel_penalty_msat(&self, short_channel_id: u64, _send_amt: u64, _capacity_msat: u64, _source: &NodeId, _target: &NodeId) -> u64 {
+               fn channel_penalty_msat(&self, short_channel_id: u64, _: &NodeId, _: &NodeId, _: ChannelUsage) -> u64 {
                        if short_channel_id == self.short_channel_id { u64::max_value() } else { 0 }
                }
 
@@ -4952,7 +5281,7 @@ mod tests {
        }
 
        impl Score for BadNodeScorer {
-               fn channel_penalty_msat(&self, _short_channel_id: u64, _send_amt: u64, _capacity_msat: u64, _source: &NodeId, target: &NodeId) -> u64 {
+               fn channel_penalty_msat(&self, _: u64, _: &NodeId, target: &NodeId, _: ChannelUsage) -> u64 {
                        if *target == self.node_id { u64::max_value() } else { 0 }
                }
 
@@ -5091,7 +5420,7 @@ mod tests {
                        .with_max_total_cltv_expiry_delta(feasible_max_total_cltv_delta);
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
-               let route = get_route(&our_id, &feasible_payment_params, &network_graph, None, 100, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
+               let route = get_route(&our_id, &feasible_payment_params, &network_graph, None, 100, 0, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
                let path = route.paths[0].iter().map(|hop| hop.short_channel_id).collect::<Vec<_>>();
                assert_ne!(path.len(), 0);
 
@@ -5099,7 +5428,36 @@ mod tests {
                let fail_max_total_cltv_delta = 23;
                let fail_payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(last_hops(&nodes))
                        .with_max_total_cltv_expiry_delta(fail_max_total_cltv_delta);
-               match get_route(&our_id, &fail_payment_params, &network_graph, None, 100, 42, Arc::clone(&logger), &scorer, &random_seed_bytes)
+               match get_route(&our_id, &fail_payment_params, &network_graph, None, 100, 0, Arc::clone(&logger), &scorer, &random_seed_bytes)
+               {
+                       Err(LightningError { err, .. } ) => {
+                               assert_eq!(err, "Failed to find a path to the given destination");
+                       },
+                       Ok(_) => panic!("Expected error"),
+               }
+       }
+
+       #[test]
+       fn limits_path_length() {
+               let (secp_ctx, network, _, _, logger) = build_line_graph();
+               let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
+               let network_graph = network.read_only();
+
+               let scorer = test_utils::TestScorer::with_penalty(0);
+               let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
+               let random_seed_bytes = keys_manager.get_secure_random_bytes();
+
+               // First check we can actually create a long route on this graph.
+               let feasible_payment_params = PaymentParameters::from_node_id(nodes[18]);
+               let route = get_route(&our_id, &feasible_payment_params, &network_graph, None, 100, 0,
+                       Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
+               let path = route.paths[0].iter().map(|hop| hop.short_channel_id).collect::<Vec<_>>();
+               assert!(path.len() == MAX_PATH_LENGTH_ESTIMATE.into());
+
+               // But we can't create a path surpassing the MAX_PATH_LENGTH_ESTIMATE limit.
+               let fail_payment_params = PaymentParameters::from_node_id(nodes[19]);
+               match get_route(&our_id, &fail_payment_params, &network_graph, None, 100, 0,
+                       Arc::clone(&logger), &scorer, &random_seed_bytes)
                {
                        Err(LightningError { err, .. } ) => {
                                assert_eq!(err, "Failed to find a path to the given destination");
@@ -5208,6 +5566,26 @@ mod tests {
                assert!(path_plausibility.iter().all(|x| *x));
        }
 
+       #[test]
+       fn builds_correct_path_from_hops() {
+               let (secp_ctx, network, _, _, logger) = build_graph();
+               let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
+               let network_graph = network.read_only();
+
+               let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
+               let random_seed_bytes = keys_manager.get_secure_random_bytes();
+
+               let payment_params = PaymentParameters::from_node_id(nodes[3]);
+               let hops = [nodes[1], nodes[2], nodes[4], nodes[3]];
+               let route = build_route_from_hops_internal(&our_id, &hops, &payment_params,
+                        &network_graph, 100, 0, Arc::clone(&logger), &random_seed_bytes).unwrap();
+               let route_hop_pubkeys = route.paths[0].iter().map(|hop| hop.pubkey).collect::<Vec<_>>();
+               assert_eq!(hops.len(), route.paths[0].len());
+               for (idx, hop_pubkey) in hops.iter().enumerate() {
+                       assert!(*hop_pubkey == route_hop_pubkeys[idx]);
+               }
+       }
+
        #[cfg(not(feature = "no-std"))]
        pub(super) fn random_init_seed() -> u64 {
                // Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG.
@@ -5217,7 +5595,7 @@ mod tests {
                seed
        }
        #[cfg(not(feature = "no-std"))]
-       use util::ser::Readable;
+       use util::ser::ReadableArgs;
 
        #[test]
        #[cfg(not(feature = "no-std"))]
@@ -5231,7 +5609,8 @@ mod tests {
                                return;
                        },
                };
-               let graph = NetworkGraph::read(&mut d).unwrap();
+               let logger = test_utils::TestLogger::new();
+               let graph = NetworkGraph::read(&mut d, &logger).unwrap();
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
 
@@ -5247,8 +5626,8 @@ mod tests {
                                let payment_params = PaymentParameters::from_node_id(dst);
                                let amt = seed as u64 % 200_000_000;
                                let params = ProbabilisticScoringParameters::default();
-                               let scorer = ProbabilisticScorer::new(params, &graph);
-                               if get_route(src, &payment_params, &graph.read_only(), None, amt, 42, &test_utils::TestLogger::new(), &scorer, &random_seed_bytes).is_ok() {
+                               let scorer = ProbabilisticScorer::new(params, &graph, &logger);
+                               if get_route(src, &payment_params, &graph.read_only(), None, amt, 42, &logger, &scorer, &random_seed_bytes).is_ok() {
                                        continue 'load_endpoints;
                                }
                        }
@@ -5267,7 +5646,8 @@ mod tests {
                                return;
                        },
                };
-               let graph = NetworkGraph::read(&mut d).unwrap();
+               let logger = test_utils::TestLogger::new();
+               let graph = NetworkGraph::read(&mut d, &logger).unwrap();
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
 
@@ -5283,8 +5663,8 @@ mod tests {
                                let payment_params = PaymentParameters::from_node_id(dst).with_features(InvoiceFeatures::known());
                                let amt = seed as u64 % 200_000_000;
                                let params = ProbabilisticScoringParameters::default();
-                               let scorer = ProbabilisticScorer::new(params, &graph);
-                               if get_route(src, &payment_params, &graph.read_only(), None, amt, 42, &test_utils::TestLogger::new(), &scorer, &random_seed_bytes).is_ok() {
+                               let scorer = ProbabilisticScorer::new(params, &graph, &logger);
+                               if get_route(src, &payment_params, &graph.read_only(), None, amt, 42, &logger, &scorer, &random_seed_bytes).is_ok() {
                                        continue 'load_endpoints;
                                }
                        }
@@ -5328,8 +5708,10 @@ mod benches {
        use chain::keysinterface::{KeysManager,KeysInterface};
        use ln::channelmanager::{ChannelCounterparty, ChannelDetails};
        use ln::features::{InitFeatures, InvoiceFeatures};
-       use routing::scoring::{FixedPenaltyScorer, ProbabilisticScorer, ProbabilisticScoringParameters, Scorer};
+       use routing::gossip::NetworkGraph;
+       use routing::scoring::{FixedPenaltyScorer, ProbabilisticScorer, ProbabilisticScoringParameters};
        use util::logger::{Logger, Record};
+       use util::ser::ReadableArgs;
 
        use test::Bencher;
 
@@ -5338,9 +5720,9 @@ mod benches {
                fn log(&self, _record: &Record) {}
        }
 
-       fn read_network_graph() -> NetworkGraph {
+       fn read_network_graph(logger: &DummyLogger) -> NetworkGraph<&DummyLogger> {
                let mut d = test_utils::get_route_file().unwrap();
-               NetworkGraph::read(&mut d).unwrap()
+               NetworkGraph::read(&mut d, logger).unwrap()
        }
 
        fn payer_pubkey() -> PublicKey {
@@ -5357,72 +5739,71 @@ mod benches {
                                node_id,
                                unspendable_punishment_reserve: 0,
                                forwarding_info: None,
+                               outbound_htlc_minimum_msat: None,
+                               outbound_htlc_maximum_msat: None,
                        },
                        funding_txo: Some(OutPoint {
                                txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0
                        }),
+                       channel_type: None,
                        short_channel_id: Some(1),
+                       inbound_scid_alias: None,
+                       outbound_scid_alias: None,
                        channel_value_satoshis: 10_000_000,
                        user_channel_id: 0,
                        balance_msat: 10_000_000,
                        outbound_capacity_msat: 10_000_000,
+                       next_outbound_htlc_limit_msat: 10_000_000,
                        inbound_capacity_msat: 0,
                        unspendable_punishment_reserve: None,
                        confirmations_required: None,
                        force_close_spend_delay: None,
                        is_outbound: true,
-                       is_funding_locked: true,
+                       is_channel_ready: true,
                        is_usable: true,
                        is_public: true,
+                       inbound_htlc_minimum_msat: None,
+                       inbound_htlc_maximum_msat: None,
                }
        }
 
        #[bench]
        fn generate_routes_with_zero_penalty_scorer(bench: &mut Bencher) {
-               let network_graph = read_network_graph();
+               let logger = DummyLogger {};
+               let network_graph = read_network_graph(&logger);
                let scorer = FixedPenaltyScorer::with_penalty(0);
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
        }
 
        #[bench]
        fn generate_mpp_routes_with_zero_penalty_scorer(bench: &mut Bencher) {
-               let network_graph = read_network_graph();
+               let logger = DummyLogger {};
+               let network_graph = read_network_graph(&logger);
                let scorer = FixedPenaltyScorer::with_penalty(0);
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
        }
 
-       #[bench]
-       fn generate_routes_with_default_scorer(bench: &mut Bencher) {
-               let network_graph = read_network_graph();
-               let scorer = Scorer::default();
-               generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
-       }
-
-       #[bench]
-       fn generate_mpp_routes_with_default_scorer(bench: &mut Bencher) {
-               let network_graph = read_network_graph();
-               let scorer = Scorer::default();
-               generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
-       }
-
        #[bench]
        fn generate_routes_with_probabilistic_scorer(bench: &mut Bencher) {
-               let network_graph = read_network_graph();
+               let logger = DummyLogger {};
+               let network_graph = read_network_graph(&logger);
                let params = ProbabilisticScoringParameters::default();
-               let scorer = ProbabilisticScorer::new(params, &network_graph);
+               let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
        }
 
        #[bench]
        fn generate_mpp_routes_with_probabilistic_scorer(bench: &mut Bencher) {
-               let network_graph = read_network_graph();
+               let logger = DummyLogger {};
+               let network_graph = read_network_graph(&logger);
                let params = ProbabilisticScoringParameters::default();
-               let scorer = ProbabilisticScorer::new(params, &network_graph);
+               let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
        }
 
        fn generate_routes<S: Score>(
-               bench: &mut Bencher, graph: &NetworkGraph, mut scorer: S, features: InvoiceFeatures
+               bench: &mut Bencher, graph: &NetworkGraph<&DummyLogger>, mut scorer: S,
+               features: InvoiceFeatures
        ) {
                let nodes = graph.read_only().nodes().clone();
                let payer = payer_pubkey();