Merge pull request #1524 from ViktorTigerstrom/2022-06-update-fail-holding-cell-htlcs...
[rust-lightning] / lightning / src / routing / router.rs
index 7536011d06d72782672f91ff24a499f1681aa5b4..90e658604ad1058040643e5b6be48fd93cfe29a8 100644 (file)
@@ -9,7 +9,7 @@
 
 //! 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::PublicKey;
@@ -17,9 +17,9 @@ 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;
 
@@ -151,8 +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)]
@@ -369,7 +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,
@@ -383,7 +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,
                }
@@ -650,8 +650,8 @@ fn default_node_features() -> NodeFeatures {
 /// 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` /
@@ -670,22 +670,18 @@ fn default_node_features() -> NodeFeatures {
 ///
 /// [`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>(
@@ -806,7 +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 {
@@ -1066,10 +1062,16 @@ where L::Target: Logger {
                                                                }
                                                        }
 
-                                                       let available_liquidity_msat = htlc_maximum_msat - used_liquidity_msat;
-                                                       let path_penalty_msat = $next_hops_path_penalty_msat.saturating_add(
-                                                               scorer.channel_penalty_msat(short_channel_id, amount_to_transfer_over_msat,
-                                                                       available_liquidity_msat, &$src_node_id, &$dest_node_id));
+                                                       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,
@@ -1295,16 +1297,6 @@ where L::Target: Logger {
                                                        short_channel_id: hop.short_channel_id,
                                                })
                                                .unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop });
-                                       let amount_to_transfer_msat = final_value_msat + aggregate_next_hops_fee_msat;
-                                       let capacity_msat = candidate.effective_capacity().as_msat();
-                                       aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
-                                               .saturating_add(scorer.channel_penalty_msat(hop.short_channel_id, amount_to_transfer_msat, capacity_msat, &source, &target));
-
-                                       aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
-                                               .saturating_add(hop.cltv_expiry_delta as u32);
-
-                                       aggregate_next_hops_path_length = aggregate_next_hops_path_length
-                                               .saturating_add(1);
 
                                        if !add_entry!(candidate, source, target, aggregate_next_hops_fee_msat,
                                                                path_value_msat, aggregate_next_hops_path_htlc_minimum_msat,
@@ -1316,6 +1308,25 @@ where L::Target: Logger {
                                                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
+                                               .saturating_add(channel_penalty_msat);
+
+                                       aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
+                                               .saturating_add(hop.cltv_expiry_delta as u32);
+
+                                       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 {
@@ -1401,7 +1412,7 @@ where L::Target: Logger {
                                        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;
@@ -1688,7 +1699,9 @@ 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();
 
@@ -1770,13 +1783,86 @@ 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, default_node_features,
+       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::Score;
+       use routing::scoring::{ChannelUsage, Score};
        use chain::transaction::OutPoint;
        use chain::keysinterface::KeysInterface;
        use ln::features::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
@@ -1820,6 +1906,7 @@ mod tests {
                        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,
@@ -1830,7 +1917,7 @@ mod tests {
                        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,
@@ -1839,7 +1926,7 @@ mod tests {
 
        // 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);
@@ -1864,14 +1951,14 @@ mod tests {
                        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()[..])[..]);
@@ -1880,14 +1967,14 @@ mod tests {
                        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);
@@ -1907,7 +1994,7 @@ mod tests {
                        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!()
                };
@@ -1942,15 +2029,16 @@ mod tests {
        }
 
        fn build_line_graph() -> (
-               Secp256k1<All>, sync::Arc<NetworkGraph>, NetGraphMsgHandler<sync::Arc<NetworkGraph>,
-               sync::Arc<test_utils::TestChainSource>, sync::Arc<crate::util::test_utils::TestLogger>>,
+               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 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 node 19:
                // our_id -1(1)2- node0 -1(2)2- node1 - ... - node19
@@ -1959,9 +2047,9 @@ mod tests {
                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(&net_graph_msg_handler, &secp_ctx, &cur_privkey, &next_privkey,
+                       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(&net_graph_msg_handler, &secp_ctx, &cur_privkey, UnsignedChannelUpdate {
+                       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,
@@ -1973,7 +2061,7 @@ mod tests {
                                fee_proportional_millionths: 0,
                                excess_data: Vec::new()
                        });
-                       update_channel(&net_graph_msg_handler, &secp_ctx, &next_privkey, UnsignedChannelUpdate {
+                       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,
@@ -1985,25 +2073,26 @@ mod tests {
                                fee_proportional_millionths: 0,
                                excess_data: Vec::new()
                        });
-                       add_or_update_node(&net_graph_msg_handler, &secp_ctx, next_privkey,
+                       add_or_update_node(&gossip_sync, &secp_ctx, next_privkey,
                                NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
                }
 
-               (secp_ctx, network_graph, net_graph_msg_handler, chain_monitor, logger)
+               (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-
@@ -2065,8 +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,
@@ -2079,10 +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,
@@ -2094,7 +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,
@@ -2107,10 +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,
@@ -2122,7 +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,
@@ -2135,10 +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,
@@ -2150,7 +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,
@@ -2163,8 +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,
@@ -2176,7 +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,
@@ -2189,8 +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,
@@ -2202,7 +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,
@@ -2215,10 +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,
@@ -2230,7 +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,
@@ -2243,8 +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,
@@ -2256,7 +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,
@@ -2269,12 +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,
@@ -2286,7 +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,
@@ -2299,9 +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]
@@ -2361,7 +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);
@@ -2371,7 +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,
@@ -2383,7 +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,
@@ -2395,7 +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,
@@ -2407,7 +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,
@@ -2419,7 +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,
@@ -2434,7 +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,
@@ -2449,7 +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,
@@ -2468,7 +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,
@@ -2488,7 +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);
@@ -2498,7 +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,
@@ -2510,7 +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,
@@ -2524,7 +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,
@@ -2536,7 +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,
@@ -2550,7 +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,
@@ -2571,7 +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,
@@ -2583,7 +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,
@@ -2595,7 +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,
@@ -2626,7 +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);
@@ -2634,7 +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,
@@ -2646,7 +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,
@@ -2686,7 +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);
@@ -2696,9 +2785,9 @@ mod tests {
                // Disable nodes 1, 2, and 8 by requiring unknown feature bits
                let mut unknown_features = NodeFeatures::known();
                unknown_features.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);
+               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) {
@@ -3041,7 +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());
@@ -3052,7 +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,
@@ -3064,7 +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,
@@ -3111,7 +3200,7 @@ mod tests {
 
        #[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();
@@ -3124,7 +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,
@@ -3136,7 +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,
@@ -3402,8 +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]
@@ -3454,7 +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);
@@ -3465,7 +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,
@@ -3477,7 +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,
@@ -3492,7 +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,
@@ -3507,7 +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,
@@ -3540,7 +3633,7 @@ mod tests {
 
                // 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,
@@ -3575,7 +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,
@@ -3590,7 +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,
@@ -3625,7 +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,
@@ -3645,10 +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,
@@ -3660,7 +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,
@@ -3692,7 +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,
@@ -3728,7 +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);
@@ -3740,7 +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,
@@ -3752,7 +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,
@@ -3767,7 +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,
@@ -3779,7 +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,
@@ -3792,7 +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,
@@ -3804,7 +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,
@@ -3853,7 +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);
@@ -3861,7 +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,
@@ -3873,7 +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,
@@ -3901,7 +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);
@@ -3917,7 +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,
@@ -3929,7 +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,
@@ -3944,7 +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,
@@ -3956,7 +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,
@@ -3971,7 +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,
@@ -3983,7 +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,
@@ -4034,7 +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);
@@ -4049,7 +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,
@@ -4061,7 +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,
@@ -4075,7 +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,
@@ -4087,7 +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,
@@ -4101,8 +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,
@@ -4118,7 +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,
@@ -4130,7 +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,
@@ -4143,7 +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,
@@ -4155,7 +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,
@@ -4198,7 +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);
@@ -4217,7 +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,
@@ -4229,7 +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,
@@ -4243,7 +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,
@@ -4255,7 +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,
@@ -4269,8 +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,
@@ -4286,7 +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,
@@ -4298,7 +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,
@@ -4311,7 +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,
@@ -4323,7 +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,
@@ -4367,7 +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);
@@ -4384,7 +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,
@@ -4397,7 +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,
@@ -4411,7 +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,
@@ -4423,7 +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,
@@ -4436,8 +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,
@@ -4460,7 +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,
@@ -4472,7 +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,
@@ -4485,7 +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,
@@ -4497,7 +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,
@@ -4548,7 +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);
@@ -4568,7 +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,
@@ -4580,7 +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,
@@ -4592,7 +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,
@@ -4604,7 +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,
@@ -4638,7 +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);
@@ -4655,7 +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,
@@ -4667,7 +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,
@@ -4681,7 +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,
@@ -4693,7 +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,
@@ -4707,7 +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,
@@ -4719,7 +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,
@@ -4795,17 +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,
@@ -4817,10 +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,
@@ -4832,10 +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,
@@ -4847,10 +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,
@@ -4862,10 +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,
@@ -4878,8 +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,
@@ -4891,7 +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.
@@ -4928,7 +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);
@@ -4937,7 +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,
@@ -4950,7 +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,
@@ -4992,7 +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);
@@ -5002,7 +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,
@@ -5014,7 +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,
@@ -5061,8 +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);
@@ -5168,7 +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 }
                }
 
@@ -5186,7 +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 }
                }
 
@@ -5471,6 +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.
@@ -5480,7 +5595,7 @@ mod tests {
                seed
        }
        #[cfg(not(feature = "no-std"))]
-       use util::ser::Readable;
+       use util::ser::ReadableArgs;
 
        #[test]
        #[cfg(not(feature = "no-std"))]
@@ -5494,7 +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();
 
@@ -5510,7 +5626,6 @@ mod tests {
                                let payment_params = PaymentParameters::from_node_id(dst);
                                let amt = seed as u64 % 200_000_000;
                                let params = ProbabilisticScoringParameters::default();
-                               let logger = test_utils::TestLogger::new();
                                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;
@@ -5531,7 +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();
 
@@ -5547,7 +5663,6 @@ 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 logger = test_utils::TestLogger::new();
                                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;
@@ -5593,9 +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::test_utils::TestLogger;
+       use util::ser::ReadableArgs;
 
        use test::Bencher;
 
@@ -5604,9 +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 {
@@ -5632,6 +5748,7 @@ mod benches {
                        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,
@@ -5642,7 +5759,7 @@ mod benches {
                        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,
@@ -5652,36 +5769,24 @@ mod benches {
 
        #[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 logger = TestLogger::new();
-               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, &logger);
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
@@ -5689,15 +5794,16 @@ mod benches {
 
        #[bench]
        fn generate_mpp_routes_with_probabilistic_scorer(bench: &mut Bencher) {
-               let logger = TestLogger::new();
-               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, &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();