X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Frouting%2Frouter.rs;h=634282d6c4b1f202fd0867312fc3dd83fc9b57fb;hb=f512586c3ffa5927024d82a409e502c4835eba16;hp=5bb81a033eb697193cde37776c8f9a9dadde04c8;hpb=2010670ac153ee1aeb4ccc40ee64a8b86ed54397;p=rust-lightning

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index 5bb81a03..634282d6 100644
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -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;
@@ -17,8 +17,8 @@ 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::gossip::{DirectedChannelInfoWithUpdate, EffectiveCapacity, ReadOnlyNetworkGraph, NodeId, RoutingFees};
 use routing::scoring::{ChannelUsage, Score};
-use routing::network_graph::{DirectedChannelInfoWithUpdate, EffectiveCapacity, NetworkGraph, ReadOnlyNetworkGraph, NodeId, RoutingFees};
 use util::ser::{Writeable, Readable, Writer};
 use util::logger::{Level, Logger};
 use util::chacha20::ChaCha20;
@@ -176,6 +176,11 @@ impl_writeable_tlv_based!(RouteParameters, {
 /// Maximum total CTLV difference we allow for a full payment path.
 pub const DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA: u32 = 1008;
 
+/// Maximum number of paths we allow an MPP payment to have.
+// The default limit is currently set rather arbitrary - there aren't any real fundamental path-count
+// limits, but for now more than 10 paths likely carries too much one-path failure.
+pub const DEFAULT_MAX_MPP_PATH_COUNT: u8 = 10;
+
 // The median hop CLTV expiry delta currently seen in the network.
 const MEDIAN_HOP_CLTV_EXPIRY_DELTA: u32 = 40;
 
@@ -214,13 +219,19 @@ pub struct PaymentParameters {
 	pub expiry_time: Option<u64>,
 
 	/// The maximum total CLTV delta we accept for the route.
+	/// Defaults to [`DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA`].
 	pub max_total_cltv_expiry_delta: u32,
+
+	/// The maximum number of paths that may be used by MPP payments.
+	/// Defaults to [`DEFAULT_MAX_MPP_PATH_COUNT`].
+	pub max_mpp_path_count: u8,
 }
 
 impl_writeable_tlv_based!(PaymentParameters, {
 	(0, payee_pubkey, required),
 	(1, max_total_cltv_expiry_delta, (default_value, DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA)),
 	(2, features, option),
+	(3, max_mpp_path_count, (default_value, DEFAULT_MAX_MPP_PATH_COUNT)),
 	(4, route_hints, vec_type),
 	(6, expiry_time, option),
 });
@@ -234,6 +245,7 @@ impl PaymentParameters {
 			route_hints: vec![],
 			expiry_time: None,
 			max_total_cltv_expiry_delta: DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA,
+			max_mpp_path_count: DEFAULT_MAX_MPP_PATH_COUNT,
 		}
 	}
 
@@ -269,6 +281,13 @@ impl PaymentParameters {
 	pub fn with_max_total_cltv_expiry_delta(self, max_total_cltv_expiry_delta: u32) -> Self {
 		Self { max_total_cltv_expiry_delta, ..self }
 	}
+
+	/// Includes a limit for the maximum number of payment paths that may be used by MPP.
+	///
+	/// (C-not exported) since bindings don't support move semantics
+	pub fn with_max_mpp_path_count(self, max_mpp_path_count: u8) -> Self {
+		Self { max_mpp_path_count, ..self }
+	}
 }
 
 /// A list of hops along a payment path terminating with a channel to the recipient.
@@ -369,7 +388,7 @@ 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 +402,7 @@ 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 +669,8 @@ 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` /
@@ -670,16 +689,17 @@ 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();
-	let mut route = get_route(our_node_pubkey, &route_params.payment_params, &network_graph, first_hops,
+	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);
+	add_random_cltv_offset(&mut route, &route_params.payment_params, network_graph, random_seed_bytes);
 	Ok(route)
 }
 
@@ -789,6 +809,11 @@ where L::Target: Logger {
 			node_info.features.supports_basic_mpp()
 		} else { false }
 	} else { false };
+
+	if allow_mpp && payment_params.max_mpp_path_count == 0 {
+		return Err(LightningError{err: "Can't find an MPP route with no paths allowed.".to_owned(), action: ErrorAction::IgnoreError});
+	}
+
 	log_trace!(logger, "Searching for a route from payer {} to payee {} {} MPP and {} first hops {}overriding the network graph", our_node_pubkey,
 		payment_params.payee_pubkey, if allow_mpp { "with" } else { "without" },
 		first_hops.map(|hops| hops.len()).unwrap_or(0), if first_hops.is_some() { "" } else { "not " });
@@ -801,7 +826,7 @@ 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 {
@@ -839,6 +864,21 @@ where L::Target: Logger {
 	let recommended_value_msat = final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR as u64;
 	let mut path_value_msat = final_value_msat;
 
+	// Routing Fragmentation Mitigation heuristic:
+	//
+	// Routing fragmentation across many payment paths increases the overall routing
+	// fees as you have irreducible routing fees per-link used (`fee_base_msat`).
+	// Taking too many smaller paths also increases the chance of payment failure.
+	// Thus to avoid this effect, we require from our collected links to provide
+	// at least a minimal contribution to the recommended value yet-to-be-fulfilled.
+	// This requirement is currently set to be 1/max_mpp_path_count of the payment
+	// value to ensure we only ever return routes that do not violate this limit.
+	let minimal_value_contribution_msat: u64 = if allow_mpp {
+		(final_value_msat + (payment_params.max_mpp_path_count as u64 - 1)) / payment_params.max_mpp_path_count as u64
+	} else {
+		final_value_msat
+	};
+
 	// Keep track of how much liquidity has been used in selected channels. Used to determine
 	// if the channel can be used by additional MPP paths or to inform path finding decisions. It is
 	// aware of direction *only* to ensure that the correct htlc_maximum_msat value is used. Hence,
@@ -846,11 +886,8 @@ where L::Target: Logger {
 	let mut used_channel_liquidities: HashMap<(u64, bool), u64> =
 		HashMap::with_capacity(network_nodes.len());
 
-	// Keeping track of how much value we already collected across other paths. Helps to decide:
-	// - how much a new path should be transferring (upper bound);
-	// - whether a channel should be disregarded because
-	//   it's available liquidity is too small comparing to how much more we need to collect;
-	// - when we want to stop looking for new paths.
+	// Keeping track of how much value we already collected across other paths. Helps to decide
+	// when we want to stop looking for new paths.
 	let mut already_collected_value_msat = 0;
 
 	for (_, channels) in first_hop_targets.iter_mut() {
@@ -912,26 +949,6 @@ where L::Target: Logger {
 							*used_liquidity_msat
 						});
 
-					// Routing Fragmentation Mitigation heuristic:
-					//
-					// Routing fragmentation across many payment paths increases the overall routing
-					// fees as you have irreducible routing fees per-link used (`fee_base_msat`).
-					// Taking too many smaller paths also increases the chance of payment failure.
-					// Thus to avoid this effect, we require from our collected links to provide
-					// at least a minimal contribution to the recommended value yet-to-be-fulfilled.
-					//
-					// This requirement is currently 5% of the remaining-to-be-collected value.
-					// This means as we successfully advance in our collection,
-					// the absolute liquidity contribution is lowered,
-					// thus increasing the number of potential channels to be selected.
-
-					// Derive the minimal liquidity contribution with a ratio of 20 (5%, rounded up)
-					// or 100% if we're not allowed to do multipath payments.
-					let minimal_value_contribution_msat: u64 = if allow_mpp {
-						(recommended_value_msat - already_collected_value_msat + 19) / 20
-					} else {
-						final_value_msat
-					};
 					// Verify the liquidity offered by this channel complies to the minimal contribution.
 					let contributes_sufficient_value = available_value_contribution_msat >= minimal_value_contribution_msat;
 					// Do not consider candidate hops that would exceed the maximum path length.
@@ -1411,7 +1428,7 @@ 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;
@@ -1503,10 +1520,8 @@ where L::Target: Logger {
 					*used_channel_liquidities.entry((victim_scid, true)).or_default() = exhausted;
 				}
 
-				// Track the total amount all our collected paths allow to send so that we:
-				// - know when to stop looking for more paths
-				// - know which of the hops are useless considering how much more sats we need
-				//   (contributes_sufficient_value)
+				// Track the total amount all our collected paths allow to send so that we know
+				// when to stop looking for more paths
 				already_collected_value_msat += value_contribution_msat;
 
 				payment_paths.push(payment_path);
@@ -1677,6 +1692,8 @@ where L::Target: Logger {
 		});
 		selected_paths.push(path);
 	}
+	// Make sure we would never create a route with more paths than we allow.
+	debug_assert!(selected_paths.len() <= payment_params.max_mpp_path_count.into());
 
 	if let Some(features) = &payment_params.features {
 		for path in selected_paths.iter_mut() {
@@ -1787,11 +1804,10 @@ fn add_random_cltv_offset(route: &mut Route, payment_params: &PaymentParameters,
 ///
 /// 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: &NetworkGraph,
-	logger: L, random_seed_bytes: &[u8; 32]
+	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 network_graph = network.read_only();
 	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)?;
@@ -1858,7 +1874,7 @@ fn build_route_from_hops_internal<L: Deref>(
 
 #[cfg(test)]
 mod tests {
-	use routing::network_graph::{NetworkGraph, NetGraphMsgHandler, NodeId};
+	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};
@@ -1906,6 +1922,7 @@ 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,
@@ -1916,16 +1933,17 @@ 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,
+			config: None,
 		}
 	}
 
 	// Using the same keys for LN and BTC ids
 	fn add_channel(
-		net_graph_msg_handler: &NetGraphMsgHandler<Arc<NetworkGraph>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
+		gossip_sync: &P2PGossipSync<Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
 		secp_ctx: &Secp256k1<All>, node_1_privkey: &SecretKey, node_2_privkey: &SecretKey, features: ChannelFeatures, short_channel_id: u64
 	) {
 		let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
@@ -1950,14 +1968,14 @@ 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()[..])[..]);
@@ -1966,14 +1984,14 @@ 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);
@@ -1993,7 +2011,7 @@ 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!()
 		};
@@ -2028,15 +2046,16 @@ 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
@@ -2045,9 +2064,9 @@ 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,
@@ -2059,7 +2078,7 @@ 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,
@@ -2071,25 +2090,26 @@ 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-
@@ -2151,8 +2171,8 @@ 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,
@@ -2165,10 +2185,10 @@ 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,
@@ -2180,7 +2200,7 @@ 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,
@@ -2193,10 +2213,10 @@ 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,
@@ -2208,7 +2228,7 @@ 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,
@@ -2221,10 +2241,10 @@ 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,
@@ -2236,7 +2256,7 @@ 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,
@@ -2249,8 +2269,8 @@ 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,
@@ -2262,7 +2282,7 @@ 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,
@@ -2275,8 +2295,8 @@ 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,
@@ -2288,7 +2308,7 @@ 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,
@@ -2301,10 +2321,10 @@ 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,
@@ -2316,7 +2336,7 @@ 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,
@@ -2329,8 +2349,8 @@ 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,
@@ -2342,7 +2362,7 @@ 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,
@@ -2355,12 +2375,12 @@ 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,
@@ -2372,7 +2392,7 @@ 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,
@@ -2385,9 +2405,9 @@ 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]
@@ -2447,7 +2467,7 @@ 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);
@@ -2457,7 +2477,7 @@ 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,
@@ -2469,7 +2489,7 @@ 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,
@@ -2481,7 +2501,7 @@ 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,
@@ -2493,7 +2513,7 @@ 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,
@@ -2505,7 +2525,7 @@ 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,
@@ -2520,7 +2540,7 @@ 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,
@@ -2535,7 +2555,7 @@ 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,
@@ -2554,7 +2574,7 @@ 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,
@@ -2574,7 +2594,7 @@ 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);
@@ -2584,7 +2604,7 @@ 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,
@@ -2596,7 +2616,7 @@ 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,
@@ -2610,7 +2630,7 @@ 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,
@@ -2622,7 +2642,7 @@ 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,
@@ -2636,7 +2656,7 @@ 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,
@@ -2657,7 +2677,7 @@ 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,
@@ -2669,7 +2689,7 @@ 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,
@@ -2681,7 +2701,7 @@ 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,
@@ -2712,7 +2732,7 @@ 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);
@@ -2720,7 +2740,7 @@ 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,
@@ -2732,7 +2752,7 @@ 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,
@@ -2772,7 +2792,7 @@ 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);
@@ -2782,9 +2802,9 @@ 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) {
@@ -3127,7 +3147,7 @@ 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());
@@ -3138,7 +3158,7 @@ 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,
@@ -3150,7 +3170,7 @@ 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,
@@ -3197,7 +3217,7 @@ 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();
@@ -3210,7 +3230,7 @@ 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,
@@ -3222,7 +3242,7 @@ 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,
@@ -3488,8 +3508,12 @@ 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]
@@ -3540,7 +3564,7 @@ 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);
@@ -3551,7 +3575,7 @@ 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,
@@ -3563,7 +3587,7 @@ 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,
@@ -3578,7 +3602,7 @@ 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,
@@ -3593,7 +3617,7 @@ 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,
@@ -3626,7 +3650,7 @@ 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,
@@ -3661,7 +3685,7 @@ 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,
@@ -3676,7 +3700,7 @@ 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,
@@ -3711,7 +3735,7 @@ 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,
@@ -3731,10 +3755,10 @@ 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,
@@ -3746,7 +3770,7 @@ 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,
@@ -3778,7 +3802,7 @@ 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,
@@ -3814,7 +3838,7 @@ 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);
@@ -3826,7 +3850,7 @@ 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,
@@ -3838,7 +3862,7 @@ 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,
@@ -3853,7 +3877,7 @@ 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,
@@ -3865,7 +3889,7 @@ 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,
@@ -3878,7 +3902,7 @@ 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,
@@ -3890,7 +3914,7 @@ 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,
@@ -3939,7 +3963,7 @@ 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);
@@ -3947,7 +3971,7 @@ 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,
@@ -3959,7 +3983,7 @@ 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,
@@ -3987,12 +4011,13 @@ 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);
 		let random_seed_bytes = keys_manager.get_secure_random_bytes();
-		let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
+		let payment_params = PaymentParameters::from_node_id(nodes[2])
+			.with_features(InvoiceFeatures::known());
 
 		// We need a route consisting of 3 paths:
 		// From our node to node2 via node0, node7, node1 (three paths one hop each).
@@ -4003,7 +4028,7 @@ 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,
@@ -4015,7 +4040,7 @@ 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,
@@ -4030,7 +4055,7 @@ 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,
@@ -4042,7 +4067,7 @@ 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,
@@ -4057,7 +4082,7 @@ 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,
@@ -4069,7 +4094,7 @@ 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,
@@ -4085,15 +4110,39 @@ mod tests {
 		{
 			// Attempt to route more than available results in a failure.
 			if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(
-					&our_id, &payment_params, &network_graph.read_only(), None, 300_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes) {
-				assert_eq!(err, "Failed to find a sufficient route to the given destination");
+				&our_id, &payment_params, &network_graph.read_only(), None, 300_000, 42,
+				Arc::clone(&logger), &scorer, &random_seed_bytes) {
+					assert_eq!(err, "Failed to find a sufficient route to the given destination");
+			} else { panic!(); }
+		}
+
+		{
+			// Attempt to route while setting max_mpp_path_count to 0 results in a failure.
+			let zero_payment_params = payment_params.clone().with_max_mpp_path_count(0);
+			if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(
+				&our_id, &zero_payment_params, &network_graph.read_only(), None, 100, 42,
+				Arc::clone(&logger), &scorer, &random_seed_bytes) {
+					assert_eq!(err, "Can't find an MPP route with no paths allowed.");
+			} else { panic!(); }
+		}
+
+		{
+			// Attempt to route while setting max_mpp_path_count to 3 results in a failure.
+			// This is the case because the minimal_value_contribution_msat would require each path
+			// to account for 1/3 of the total value, which is violated by 2 out of 3 paths.
+			let fail_payment_params = payment_params.clone().with_max_mpp_path_count(3);
+			if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(
+				&our_id, &fail_payment_params, &network_graph.read_only(), None, 250_000, 42,
+				Arc::clone(&logger), &scorer, &random_seed_bytes) {
+					assert_eq!(err, "Failed to find a sufficient route to the given destination");
 			} else { panic!(); }
 		}
 
 		{
 			// Now, attempt to route 250 sats (just a bit below the capacity).
 			// Our algorithm should provide us with these 3 paths.
-			let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 250_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
+			let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None,
+				250_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
 			assert_eq!(route.paths.len(), 3);
 			let mut total_amount_paid_msat = 0;
 			for path in &route.paths {
@@ -4106,7 +4155,8 @@ mod tests {
 
 		{
 			// Attempt to route an exact amount is also fine
-			let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 290_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
+			let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None,
+				290_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
 			assert_eq!(route.paths.len(), 3);
 			let mut total_amount_paid_msat = 0;
 			for path in &route.paths {
@@ -4120,7 +4170,7 @@ 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);
@@ -4135,7 +4185,7 @@ 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,
@@ -4147,7 +4197,7 @@ 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,
@@ -4161,7 +4211,7 @@ 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,
@@ -4173,7 +4223,7 @@ 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,
@@ -4187,8 +4237,8 @@ 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,
@@ -4204,7 +4254,7 @@ 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,
@@ -4216,7 +4266,7 @@ 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,
@@ -4229,7 +4279,7 @@ 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,
@@ -4241,7 +4291,7 @@ 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,
@@ -4284,7 +4334,7 @@ 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);
@@ -4303,7 +4353,7 @@ 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,
@@ -4315,7 +4365,7 @@ 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,
@@ -4329,7 +4379,7 @@ 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,
@@ -4341,7 +4391,7 @@ 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,
@@ -4355,8 +4405,8 @@ 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,
@@ -4372,7 +4422,7 @@ 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,
@@ -4384,7 +4434,7 @@ 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,
@@ -4397,7 +4447,7 @@ 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,
@@ -4409,7 +4459,7 @@ 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,
@@ -4453,7 +4503,7 @@ 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);
@@ -4470,7 +4520,7 @@ 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,
@@ -4483,7 +4533,7 @@ 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,
@@ -4497,7 +4547,7 @@ 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,
@@ -4509,7 +4559,7 @@ 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,
@@ -4522,8 +4572,8 @@ 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,
@@ -4546,7 +4596,7 @@ 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,
@@ -4558,7 +4608,7 @@ 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,
@@ -4571,7 +4621,7 @@ 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,
@@ -4583,7 +4633,7 @@ 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,
@@ -4634,7 +4684,7 @@ 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);
@@ -4654,7 +4704,7 @@ 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,
@@ -4666,7 +4716,7 @@ 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,
@@ -4678,7 +4728,7 @@ 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,
@@ -4690,7 +4740,7 @@ 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,
@@ -4724,7 +4774,7 @@ 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);
@@ -4741,7 +4791,7 @@ 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,
@@ -4753,7 +4803,7 @@ 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,
@@ -4767,7 +4817,7 @@ 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,
@@ -4779,7 +4829,7 @@ 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,
@@ -4793,7 +4843,7 @@ 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,
@@ -4805,7 +4855,7 @@ 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,
@@ -4881,17 +4931,18 @@ 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,
@@ -4903,10 +4954,10 @@ 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,
@@ -4918,10 +4969,10 @@ 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,
@@ -4933,10 +4984,10 @@ 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,
@@ -4948,10 +4999,10 @@ 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,
@@ -4964,8 +5015,8 @@ 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,
@@ -4977,7 +5028,7 @@ 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.
@@ -5014,7 +5065,7 @@ 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);
@@ -5023,7 +5074,7 @@ 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,
@@ -5036,7 +5087,7 @@ 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,
@@ -5078,7 +5129,7 @@ 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);
@@ -5088,7 +5139,7 @@ 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,
@@ -5100,7 +5151,7 @@ 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,
@@ -5147,8 +5198,9 @@ 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);
@@ -5586,7 +5638,7 @@ mod tests {
 		seed
 	}
 	#[cfg(not(feature = "no-std"))]
-	use util::ser::Readable;
+	use util::ser::ReadableArgs;
 
 	#[test]
 	#[cfg(not(feature = "no-std"))]
@@ -5600,7 +5652,8 @@ 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();
 
@@ -5616,7 +5669,6 @@ 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;
@@ -5637,7 +5689,8 @@ 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();
 
@@ -5653,7 +5706,6 @@ 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;
@@ -5699,9 +5751,10 @@ 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;
 
@@ -5710,9 +5763,9 @@ 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 {
@@ -5738,6 +5791,7 @@ 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,
@@ -5748,46 +5802,35 @@ 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,
 			inbound_htlc_maximum_msat: None,
+			config: None,
 		}
 	}
 
 	#[bench]
 	fn generate_routes_with_zero_penalty_scorer(bench: &mut Bencher) {
-		let network_graph = read_network_graph();
+		let logger = DummyLogger {};
+		let network_graph = read_network_graph(&logger);
 		let scorer = FixedPenaltyScorer::with_penalty(0);
 		generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
 	}
 
 	#[bench]
 	fn generate_mpp_routes_with_zero_penalty_scorer(bench: &mut Bencher) {
-		let network_graph = read_network_graph();
+		let logger = DummyLogger {};
+		let network_graph = read_network_graph(&logger);
 		let scorer = FixedPenaltyScorer::with_penalty(0);
 		generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
 	}
 
-	#[bench]
-	fn generate_routes_with_default_scorer(bench: &mut Bencher) {
-		let network_graph = read_network_graph();
-		let scorer = Scorer::default();
-		generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
-	}
-
-	#[bench]
-	fn generate_mpp_routes_with_default_scorer(bench: &mut Bencher) {
-		let network_graph = read_network_graph();
-		let scorer = Scorer::default();
-		generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
-	}
-
 	#[bench]
 	fn generate_routes_with_probabilistic_scorer(bench: &mut Bencher) {
-		let 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());
@@ -5795,15 +5838,16 @@ 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();