Da: network service backend (#695)

* Sketch up types and backend skeleton

* Pipe up sampling events

* Pipe up validation blobs events

* Added docs

* Cargo fmt

* Clippy happy

* Debug log events in validator swarm run method

nomos-da/network/core/src/behaviour/validator.rs

@@ -48,4 +48,28 @@ where
         self.dispersal.update_membership(membership.clone());
         self.replication.update_membership(membership);
     }
+
+    pub fn sampling_behaviour(&self) -> &SamplingBehaviour<Membership> {
+        &self.sampling
+    }
+
+    pub fn dispersal_behaviour(&self) -> &DispersalValidatorBehaviour<Membership> {
+        &self.dispersal
+    }
+
+    pub fn replication_behaviour(&self) -> &ReplicationBehaviour<Membership> {
+        &self.replication
+    }
+
+    pub fn sampling_behaviour_mut(&mut self) -> &mut SamplingBehaviour<Membership> {
+        &mut self.sampling
+    }
+
+    pub fn dispersal_behaviour_mut(&mut self) -> &mut DispersalValidatorBehaviour<Membership> {
+        &mut self.dispersal
+    }
+
+    pub fn replication_behaviour_mut(&mut self) -> &mut ReplicationBehaviour<Membership> {
+        &mut self.replication
+    }
 }

nomos-da/network/core/src/protocols/sampling/behaviour.rs

@@ -1,4 +1,5 @@
 // std
+use bincode::ErrorKind;
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::task::{Context, Poll};
 // crates
@@ -72,6 +73,74 @@ impl SamplingError {
     }
 }
 
+impl Clone for SamplingError {
+    fn clone(&self) -> Self {
+        match self {
+            SamplingError::Io { peer_id, error } => SamplingError::Io {
+                peer_id: *peer_id,
+                error: std::io::Error::new(error.kind(), error.to_string()),
+            },
+            SamplingError::Protocol {
+                subnetwork_id,
+                peer_id,
+                error,
+            } => SamplingError::Protocol {
+                subnetwork_id: *subnetwork_id,
+                peer_id: *peer_id,
+                error: error.clone(),
+            },
+            SamplingError::OpenStream { peer_id, error } => SamplingError::OpenStream {
+                peer_id: *peer_id,
+                error: match error {
+                    OpenStreamError::UnsupportedProtocol(protocol) => {
+                        OpenStreamError::UnsupportedProtocol(protocol.clone())
+                    }
+                    OpenStreamError::Io(error) => {
+                        OpenStreamError::Io(std::io::Error::new(error.kind(), error.to_string()))
+                    }
+                    err => OpenStreamError::Io(std::io::Error::new(
+                        std::io::ErrorKind::Other,
+                        err.to_string(),
+                    )),
+                },
+            },
+            SamplingError::Deserialize {
+                blob_id,
+                subnetwork_id,
+                peer_id,
+                error,
+            } => SamplingError::Deserialize {
+                blob_id: *blob_id,
+                subnetwork_id: *subnetwork_id,
+                peer_id: *peer_id,
+                error: clone_deserialize_error(error),
+            },
+            SamplingError::RequestChannel { request, peer_id } => SamplingError::RequestChannel {
+                request: request.clone(),
+                peer_id: *peer_id,
+            },
+            SamplingError::ResponseChannel { error, peer_id } => SamplingError::ResponseChannel {
+                peer_id: *peer_id,
+                error: *error,
+            },
+        }
+    }
+}
+
+fn clone_deserialize_error(error: &bincode::Error) -> bincode::Error {
+    Box::new(match error.as_ref() {
+        ErrorKind::Io(error) => ErrorKind::Io(std::io::Error::new(error.kind(), error.to_string())),
+        ErrorKind::InvalidUtf8Encoding(error) => ErrorKind::InvalidUtf8Encoding(*error),
+        ErrorKind::InvalidBoolEncoding(bool) => ErrorKind::InvalidBoolEncoding(*bool),
+        ErrorKind::InvalidCharEncoding => ErrorKind::InvalidCharEncoding,
+        ErrorKind::InvalidTagEncoding(tag) => ErrorKind::InvalidTagEncoding(*tag),
+        ErrorKind::DeserializeAnyNotSupported => ErrorKind::DeserializeAnyNotSupported,
+        ErrorKind::SizeLimit => ErrorKind::SizeLimit,
+        ErrorKind::SequenceMustHaveLength => ErrorKind::SequenceMustHaveLength,
+        ErrorKind::Custom(custom) => ErrorKind::Custom(custom.clone()),
+    })
+}
+
 /// Inner type representation of a Blob ID
 // TODO: Use a proper type that is common to the codebase
 type BlobId = [u8; 32];

nomos-da/network/core/src/swarm/validator.rs

@@ -1,10 +1,12 @@
 // std
 // crates
 use futures::StreamExt;
+use kzgrs_backend::common::blob::DaBlob;
 use libp2p::identity::Keypair;
 use libp2p::swarm::SwarmEvent;
 use libp2p::{PeerId, Swarm, SwarmBuilder};
-use log::debug;
+use log::{debug, error};
+use nomos_da_messages::replication::ReplicationReq;
 use tokio::sync::mpsc::{unbounded_channel, UnboundedSender};
 use tokio_stream::wrappers::UnboundedReceiverStream;
 // internal
@@ -18,6 +20,7 @@ use subnetworks_assignations::MembershipHandler;
 
 pub struct ValidatorEventsStream {
     pub sampling_events_receiver: UnboundedReceiverStream<SamplingEvent>,
+    pub validation_events_receiver: UnboundedReceiverStream<DaBlob>,
 }
 
 pub struct ValidatorSwarm<
@@ -25,6 +28,7 @@ pub struct ValidatorSwarm<
 > {
     swarm: Swarm<ValidatorBehaviour<Membership>>,
     sampling_events_sender: UnboundedSender<SamplingEvent>,
+    validation_events_sender: UnboundedSender<DaBlob>,
 }
 
 impl<Membership> ValidatorSwarm<Membership>
@@ -33,14 +37,19 @@ where
 {
     pub fn new(key: Keypair, membership: Membership) -> (Self, ValidatorEventsStream) {
         let (sampling_events_sender, sampling_events_receiver) = unbounded_channel();
+        let (validation_events_sender, validation_events_receiver) = unbounded_channel();
+
         let sampling_events_receiver = UnboundedReceiverStream::new(sampling_events_receiver);
+        let validation_events_receiver = UnboundedReceiverStream::new(validation_events_receiver);
         (
             Self {
                 swarm: Self::build_swarm(key, membership),
                 sampling_events_sender,
+                validation_events_sender,
             },
             ValidatorEventsStream {
                 sampling_events_receiver,
+                validation_events_receiver,
             },
         )
     }
@@ -53,21 +62,48 @@ where
             .build()
     }
 
+    pub fn protocol_swarm(&self) -> &Swarm<ValidatorBehaviour<Membership>> {
+        &self.swarm
+    }
+
+    pub fn protocol_swarm_mut(&mut self) -> &mut Swarm<ValidatorBehaviour<Membership>> {
+        &mut self.swarm
+    }
+
     async fn handle_sampling_event(&mut self, event: SamplingEvent) {
         if let Err(e) = self.sampling_events_sender.send(event) {
             debug!("Error distributing sampling message internally: {e:?}");
         }
     }
 
-    async fn handle_dispersal_event(&mut self, _event: DispersalEvent) {
-        // TODO: hook incoming dispersal events => to replication
-        unimplemented!()
+    async fn handle_dispersal_event(&mut self, event: DispersalEvent) {
+        match event {
+            // Send message for replication
+            DispersalEvent::IncomingMessage { message } => {
+                if let Ok(blob) = bincode::deserialize::<DaBlob>(
+                    message
+                        .blob
+                        .as_ref()
+                        .expect("Message blob should not be empty")
+                        .data
+                        .as_slice(),
+                ) {
+                    if let Err(e) = self.validation_events_sender.send(blob) {
+                        error!("Error sending blob to validation: {e:?}");
+                    }
+                }
+                self.swarm
+                    .behaviour_mut()
+                    .replication_behaviour_mut()
+                    .send_message(ReplicationReq {
+                        blob: message.blob,
+                        subnetwork_id: message.subnetwork_id,
+                    });
+            }
+        }
     }
 
-    async fn handle_replication_event(&mut self, _event: ReplicationEvent) {
-        // TODO: Hook incoming blobs from replication protocol
-        unimplemented!()
-    }
+    async fn handle_replication_event(&mut self, _event: ReplicationEvent) {}
 
     async fn handle_behaviour_event(&mut self, event: ValidatorBehaviourEvent<Membership>) {
         match event {
@@ -83,33 +119,33 @@ where
         }
     }
 
-    pub async fn step(&mut self) {
-        tokio::select! {
-            Some(event) = self.swarm.next() => {
+    pub async fn run(mut self) {
+        loop {
+            if let Some(event) = self.swarm.next().await {
+                debug!("Da swarm event received: {event:?}");
                 match event {
                     SwarmEvent::Behaviour(behaviour_event) => {
                         self.handle_behaviour_event(behaviour_event).await;
-                    },
-                    SwarmEvent::ConnectionEstablished{ .. } => {}
-                    SwarmEvent::ConnectionClosed{ .. } => {}
-                    SwarmEvent::IncomingConnection{ .. } => {}
-                    SwarmEvent::IncomingConnectionError{ .. } => {}
-                    SwarmEvent::OutgoingConnectionError{ .. } => {}
-                    SwarmEvent::NewListenAddr{ .. } => {}
-                    SwarmEvent::ExpiredListenAddr{ .. } => {}
-                    SwarmEvent::ListenerClosed{ .. } => {}
-                    SwarmEvent::ListenerError{ .. } => {}
-                    SwarmEvent::Dialing{ .. } => {}
-                    SwarmEvent::NewExternalAddrCandidate{ .. } => {}
-                    SwarmEvent::ExternalAddrConfirmed{ .. } => {}
-                    SwarmEvent::ExternalAddrExpired{ .. } => {}
-                    SwarmEvent::NewExternalAddrOfPeer{ .. } => {}
+                    }
+                    SwarmEvent::ConnectionEstablished { .. } => {}
+                    SwarmEvent::ConnectionClosed { .. } => {}
+                    SwarmEvent::IncomingConnection { .. } => {}
+                    SwarmEvent::IncomingConnectionError { .. } => {}
+                    SwarmEvent::OutgoingConnectionError { .. } => {}
+                    SwarmEvent::NewListenAddr { .. } => {}
+                    SwarmEvent::ExpiredListenAddr { .. } => {}
+                    SwarmEvent::ListenerClosed { .. } => {}
+                    SwarmEvent::ListenerError { .. } => {}
+                    SwarmEvent::Dialing { .. } => {}
+                    SwarmEvent::NewExternalAddrCandidate { .. } => {}
+                    SwarmEvent::ExternalAddrConfirmed { .. } => {}
+                    SwarmEvent::ExternalAddrExpired { .. } => {}
+                    SwarmEvent::NewExternalAddrOfPeer { .. } => {}
                     event => {
                         debug!("Unsupported validator swarm event: {event:?}");
                     }
                 }
             }
-
         }
     }
 }

nomos-services/data-availability/network/Cargo.toml

@@ -8,7 +8,11 @@ async-trait = "0.1"
 futures = "0.3"
 kzgrs-backend = { path = "../../../nomos-da/kzgrs-backend" }
 overwatch-rs = { git = "https://github.com/logos-co/Overwatch", rev = "2f70806" }
+nomos-da-network-core = { path = "../../../nomos-da/network/core" }
+subnetworks-assignations = { path = "../../../nomos-da/network/subnetworks-assignations" }
+libp2p = { version = "0.54", features = ["ed25519"] }
 serde = { version = "1.0", features = ["derive"] }
 tokio = { version = "1", features = ["macros", "sync"] }
 tokio-stream = "0.1"
 tracing = "0.1"
+log = "0.4.22"

nomos-services/data-availability/network/src/backends/libp2p/mod.rs

@@ -0,0 +1 @@
+pub mod validator;

nomos-services/data-availability/network/src/backends/libp2p/validator.rs

@@ -0,0 +1,217 @@
+use crate::backends::NetworkBackend;
+use futures::{Stream, StreamExt};
+use kzgrs_backend::common::blob::DaBlob;
+use libp2p::identity::Keypair;
+use libp2p::PeerId;
+use log::error;
+use nomos_da_network_core::protocols::sampling;
+use nomos_da_network_core::protocols::sampling::behaviour::SamplingError;
+use nomos_da_network_core::swarm::validator::{ValidatorEventsStream, ValidatorSwarm};
+use nomos_da_network_core::SubnetworkId;
+use overwatch_rs::overwatch::handle::OverwatchHandle;
+use overwatch_rs::services::state::NoState;
+use std::fmt::Debug;
+use std::marker::PhantomData;
+use std::pin::Pin;
+use subnetworks_assignations::MembershipHandler;
+use tokio::sync::broadcast;
+use tokio::sync::mpsc::error::SendError;
+use tokio::sync::mpsc::UnboundedSender;
+use tokio::task::JoinHandle;
+use tokio_stream::wrappers::BroadcastStream;
+
+type BlobId = [u8; 32];
+type ColumnIdx = u32;
+
+const BROADCAST_CHANNEL_SIZE: usize = 128;
+
+/// Message that the backend replies to
+#[derive(Debug)]
+pub enum DaNetworkMessage {
+    /// Kickstart a network sapling
+    RequestSample {
+        subnetwork_id: ColumnIdx,
+        blob_id: BlobId,
+    },
+}
+
+/// Events types to subscribe to
+/// * Sampling: Incoming sampling events [success/fail]
+/// * Incoming blobs to be verified
+#[derive(Debug)]
+pub enum DaNetworkEventKind {
+    Sampling,
+    Verifying,
+}
+
+/// Sampling events coming from da network
+#[derive(Debug, Clone)]
+pub enum SamplingEvent {
+    /// A success sampling
+    SamplingSuccess { blob_id: BlobId, blob: Box<DaBlob> },
+    /// A failed sampling error
+    SamplingError { error: SamplingError },
+}
+
+/// DA network incoming events
+#[derive(Debug)]
+pub enum DaNetworkEvent {
+    Sampling(SamplingEvent),
+    Verifying(Box<DaBlob>),
+}
+
+/// DA network backend for validators
+/// Internally uses a libp2p swarm composed of the [`ValidatorBehaviour`]
+/// It forwards network messages to the corresponding subscription channels/streams
+pub struct DaNetworkValidatorBackend<Membership> {
+    // TODO: this join handles should be cancelable tasks. We should add an stop method for
+    // the `NetworkBackend` trait so if the service is stopped the backend can gracefully handle open
+    // sub-tasks as well.
+    #[allow(dead_code)]
+    task: JoinHandle<()>,
+    #[allow(dead_code)]
+    replies_task: JoinHandle<()>,
+    sampling_request_channel: UnboundedSender<(SubnetworkId, BlobId)>,
+    sampling_broadcast_receiver: broadcast::Receiver<SamplingEvent>,
+    verifying_broadcast_receiver: broadcast::Receiver<DaBlob>,
+    _membership: PhantomData<Membership>,
+}
+
+#[derive(Clone, Debug)]
+pub struct DaNetworkValidatorBackendSettings<Membership> {
+    /// Identification key
+    key: Keypair,
+    /// Membership of DA network PoV set
+    membership: Membership,
+}
+
+impl<Membership> DaNetworkValidatorBackend<Membership> {
+    /// Send the sampling request to the underlying sampling behaviour
+    async fn handle_sample_request(&self, subnetwork_id: SubnetworkId, blob_id: BlobId) {
+        if let Err(SendError((subnetwork_id, blob_id))) =
+            self.sampling_request_channel.send((subnetwork_id, blob_id))
+        {
+            error!(
+                "Error requesting sample for subnetwork id : {subnetwork_id}, blob_id: {blob_id:?}"
+            );
+        }
+    }
+}
+
+#[async_trait::async_trait]
+impl<Membership> NetworkBackend for DaNetworkValidatorBackend<Membership>
+where
+    Membership: MembershipHandler<NetworkId = SubnetworkId, Id = PeerId>
+        + Clone
+        + Debug
+        + Send
+        + Sync
+        + 'static,
+{
+    type Settings = DaNetworkValidatorBackendSettings<Membership>;
+    type State = NoState<Self::Settings>;
+    type Message = DaNetworkMessage;
+    type EventKind = DaNetworkEventKind;
+    type NetworkEvent = DaNetworkEvent;
+
+    fn new(config: Self::Settings, overwatch_handle: OverwatchHandle) -> Self {
+        let (validator_swarm, events_streams) = ValidatorSwarm::new(config.key, config.membership);
+        let sampling_request_channel = validator_swarm
+            .protocol_swarm()
+            .behaviour()
+            .sampling_behaviour()
+            .sample_request_channel();
+
+        let task = overwatch_handle.runtime().spawn(validator_swarm.run());
+        let (sampling_broadcast_sender, sampling_broadcast_receiver) =
+            broadcast::channel(BROADCAST_CHANNEL_SIZE);
+        let (verifying_broadcast_sender, verifying_broadcast_receiver) =
+            broadcast::channel(BROADCAST_CHANNEL_SIZE);
+        let replies_task = overwatch_handle
+            .runtime()
+            .spawn(handle_validator_events_stream(
+                events_streams,
+                sampling_broadcast_sender,
+                verifying_broadcast_sender,
+            ));
+
+        Self {
+            task,
+            replies_task,
+            sampling_request_channel,
+            sampling_broadcast_receiver,
+            verifying_broadcast_receiver,
+            _membership: Default::default(),
+        }
+    }
+
+    async fn process(&self, msg: Self::Message) {
+        match msg {
+            DaNetworkMessage::RequestSample {
+                subnetwork_id,
+                blob_id,
+            } => {
+                self.handle_sample_request(subnetwork_id, blob_id).await;
+            }
+        }
+    }
+
+    async fn subscribe(
+        &mut self,
+        event: Self::EventKind,
+    ) -> Pin<Box<dyn Stream<Item = Self::NetworkEvent> + Send>> {
+        match event {
+            DaNetworkEventKind::Sampling => Box::pin(
+                BroadcastStream::new(self.sampling_broadcast_receiver.resubscribe())
+                    .filter_map(|event| async { event.ok() })
+                    .map(Self::NetworkEvent::Sampling),
+            ),
+            DaNetworkEventKind::Verifying => Box::pin(
+                BroadcastStream::new(self.verifying_broadcast_receiver.resubscribe())
+                    .filter_map(|event| async { event.ok() })
+                    .map(|blob| Self::NetworkEvent::Verifying(Box::new(blob))),
+            ),
+        }
+    }
+}
+
+/// Task that handles forwarding of events to the subscriptions channels/stream
+async fn handle_validator_events_stream(
+    events_streams: ValidatorEventsStream,
+    sampling_broadcast_sender: broadcast::Sender<SamplingEvent>,
+    validation_broadcast_sender: broadcast::Sender<DaBlob>,
+) {
+    let ValidatorEventsStream {
+        mut sampling_events_receiver,
+        mut validation_events_receiver,
+    } = events_streams;
+    #[allow(clippy::never_loop)]
+    loop {
+        // WARNING: `StreamExt::next` is cancellation safe.
+        // If adding more branches check if such methods are within the cancellation safe set:
+        // https://docs.rs/tokio/latest/tokio/macro.select.html#cancellation-safety
+        tokio::select! {
+            Some(sampling_event) = StreamExt::next(&mut sampling_events_receiver) => {
+                match sampling_event {
+                    sampling::behaviour::SamplingEvent::SamplingSuccess{ blob_id, blob , .. } => {
+                        if let Err(e) = sampling_broadcast_sender.send(SamplingEvent::SamplingSuccess {blob_id, blob}){
+                            error!("Error in internal broadcast of sampling success: {e:?}");
+                        }
+                    }
+                    sampling::behaviour::SamplingEvent::IncomingSample{ .. } => {
+                        unimplemented!("Handle request/response from Sampling service");
+                    }
+                    sampling::behaviour::SamplingEvent::SamplingError{ error  } => {
+                        if let Err(e) = sampling_broadcast_sender.send(SamplingEvent::SamplingError {error}) {
+                            error!{"Error in internal broadcast of sampling error: {e:?}"};
+                        }
+                    }}
+            }
+            Some(da_blob) = StreamExt::next(&mut validation_events_receiver)=> {
+                if let Err(error) = validation_broadcast_sender.send(da_blob) {
+                    error!("Error in internal broadcast of validation for blob: {:?}", error.0);
+                }
+            }
+        }
+    }
+}

nomos-services/data-availability/network/src/backends/mock/executor.rs

@@ -1,10 +1,13 @@
+use futures::{Stream, StreamExt};
 use kzgrs_backend::common::{blob::DaBlob, build_blob_id};
 use overwatch_rs::{overwatch::handle::OverwatchHandle, services::state::NoState};
 use serde::{Deserialize, Serialize};
+use std::pin::Pin;
 use tokio::sync::{
-    broadcast::{self, Receiver},
+    broadcast::{self},
     mpsc,
 };
+use tokio_stream::wrappers::BroadcastStream;
 
 use crate::backends::NetworkBackend;
 
@@ -96,9 +99,15 @@ impl NetworkBackend for MockExecutorBackend {
         }
     }
 
-    async fn subscribe(&mut self, kind: Self::EventKind) -> Receiver<Self::NetworkEvent> {
+    async fn subscribe(
+        &mut self,
+        kind: Self::EventKind,
+    ) -> Pin<Box<dyn Stream<Item = Self::NetworkEvent> + Send>> {
         match kind {
-            EventKind::Dispersal | EventKind::Sample => self.events_tx.subscribe(),
+            EventKind::Dispersal | EventKind::Sample => Box::pin(
+                BroadcastStream::new(self.events_tx.subscribe())
+                    .filter_map(|event| async { event.ok() }),
+            ),
         }
     }
 }

nomos-services/data-availability/network/src/backends/mod.rs

@@ -1,8 +1,10 @@
+pub mod libp2p;
 pub mod mock;
 
 use super::*;
+use futures::Stream;
 use overwatch_rs::{overwatch::handle::OverwatchHandle, services::state::ServiceState};
-use tokio::sync::broadcast::Receiver;
+use std::pin::Pin;
 
 #[async_trait::async_trait]
 pub trait NetworkBackend {
@@ -14,5 +16,8 @@ pub trait NetworkBackend {
 
     fn new(config: Self::Settings, overwatch_handle: OverwatchHandle) -> Self;
     async fn process(&self, msg: Self::Message);
-    async fn subscribe(&mut self, event: Self::EventKind) -> Receiver<Self::NetworkEvent>;
+    async fn subscribe(
+        &mut self,
+        event: Self::EventKind,
+    ) -> Pin<Box<dyn Stream<Item = Self::NetworkEvent> + Send>>;
 }

nomos-services/data-availability/network/src/lib.rs

@@ -2,10 +2,11 @@ pub mod backends;
 
 // std
 use std::fmt::{self, Debug};
+use std::pin::Pin;
 // crates
 use async_trait::async_trait;
 use backends::NetworkBackend;
-use futures::StreamExt;
+use futures::{Stream, StreamExt};
 use overwatch_rs::services::life_cycle::LifecycleMessage;
 use overwatch_rs::services::{
     handle::ServiceStateHandle,
@@ -14,7 +15,6 @@ use overwatch_rs::services::{
     ServiceCore, ServiceData, ServiceId,
 };
 use serde::{Deserialize, Serialize};
-use tokio::sync::broadcast;
 use tokio::sync::oneshot;
 use tracing::error;
 // internal
@@ -23,7 +23,7 @@ pub enum DaNetworkMsg<B: NetworkBackend> {
     Process(B::Message),
     Subscribe {
         kind: B::EventKind,
-        sender: oneshot::Sender<broadcast::Receiver<B::NetworkEvent>>,
+        sender: oneshot::Sender<Pin<Box<dyn Stream<Item = B::NetworkEvent> + Send>>>,
     },
 }
 
@@ -31,10 +31,9 @@ impl<B: NetworkBackend> Debug for DaNetworkMsg<B> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         match self {
             Self::Process(msg) => write!(fmt, "DaNetworkMsg::Process({msg:?})"),
-            Self::Subscribe { kind, sender } => write!(
-                fmt,
-                "DaNetworkMsg::Subscribe{{ kind: {kind:?}, sender: {sender:?}}}"
-            ),
+            Self::Subscribe { kind, .. } => {
+                write!(fmt, "DaNetworkMsg::Subscribe{{ kind: {kind:?}}}")
+            }
         }
     }
 }
@@ -52,7 +51,7 @@ impl<B: NetworkBackend> Debug for NetworkConfig<B> {
     }
 }
 
-pub struct NetworkService<B: NetworkBackend + 'static> {
+pub struct NetworkService<B: NetworkBackend + Send + 'static> {
     backend: B,
     service_state: ServiceStateHandle<Self>,
 }
@@ -61,7 +60,7 @@ pub struct NetworkState<B: NetworkBackend> {
     _backend: B::State,
 }
 
-impl<B: NetworkBackend + 'static> ServiceData for NetworkService<B> {
+impl<B: NetworkBackend + 'static + Send> ServiceData for NetworkService<B> {
     const SERVICE_ID: ServiceId = "DaNetwork";
     type Settings = NetworkConfig<B>;
     type State = NetworkState<B>;