feat(floodsub): Add option to configure the maximum message length

Cargo.toml

@@ -82,7 +82,7 @@ libp2p-connection-limits = { version = "0.4.0", path = "misc/connection-limits"
 libp2p-core = { version = "0.42.0", path = "core" }
 libp2p-dcutr = { version = "0.12.0", path = "protocols/dcutr" }
 libp2p-dns = { version = "0.42.0", path = "transports/dns" }
-libp2p-floodsub = { version = "0.45.0", path = "protocols/floodsub" }
+libp2p-floodsub = { version = "0.46.0", path = "protocols/floodsub" }
 libp2p-gossipsub = { version = "0.47.1", path = "protocols/gossipsub" }
 libp2p-identify = { version = "0.45.0", path = "protocols/identify" }
 libp2p-identity = { version = "0.2.9" }

protocols/floodsub/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.46.0
+
+- Add a `max_message_len` option to `FloodsubConfig` for configuring the maximum message length.
+  See [PR 5588](https://github.com/libp2p/rust-libp2p/pull/5588)
+
 ## 0.45.0
 
 <!-- Update to libp2p-swarm v0.45.0 -->

protocols/floodsub/Cargo.toml

@@ -3,7 +3,7 @@ name = "libp2p-floodsub"
 edition = "2021"
 rust-version = { workspace = true }
 description = "Floodsub protocol for libp2p"
-version = "0.45.0"
+version = "0.46.0"
 authors = ["Parity Technologies <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"

protocols/floodsub/src/layer.rs

@@ -35,6 +35,7 @@ use libp2p_swarm::{
     dial_opts::DialOpts, CloseConnection, ConnectionDenied, ConnectionId, NetworkBehaviour,
     NotifyHandler, OneShotHandler, THandler, THandlerInEvent, THandlerOutEvent, ToSwarm,
 };
+use libp2p_swarm::{OneShotHandlerConfig, SubstreamProtocol};
 use smallvec::SmallVec;
 use std::collections::hash_map::{DefaultHasher, HashMap};
 use std::task::{Context, Poll};
@@ -97,6 +98,7 @@ impl Floodsub {
                             topic,
                             action: FloodsubSubscriptionAction::Subscribe,
                         }],
+                        max_message_len: self.config.max_message_len,
                     },
                 });
             }
@@ -133,6 +135,7 @@ impl Floodsub {
                         topic: topic.clone(),
                         action: FloodsubSubscriptionAction::Subscribe,
                     }],
+                    max_message_len: self.config.max_message_len,
                 },
             });
         }
@@ -163,6 +166,7 @@ impl Floodsub {
                         topic: topic.clone(),
                         action: FloodsubSubscriptionAction::Unsubscribe,
                     }],
+                    max_message_len: self.config.max_message_len,
                 },
             });
         }
@@ -263,6 +267,7 @@ impl Floodsub {
                 event: FloodsubRpc {
                     subscriptions: Vec::new(),
                     messages: vec![message.clone()],
+                    max_message_len: self.config.max_message_len,
                 },
             });
         }
@@ -293,6 +298,7 @@ impl Floodsub {
                             topic,
                             action: FloodsubSubscriptionAction::Subscribe,
                         }],
+                        max_message_len: self.config.max_message_len,
                     },
                 });
             }
@@ -338,7 +344,10 @@ impl NetworkBehaviour for Floodsub {
         _: &Multiaddr,
         _: &Multiaddr,
     ) -> Result<THandler<Self>, ConnectionDenied> {
-        Ok(Default::default())
+        Ok(OneShotHandler::new(
+            SubstreamProtocol::new(FloodsubProtocol::new(self.config.max_message_len), ()),
+            OneShotHandlerConfig::default(),
+        ))
     }
 
     fn handle_established_outbound_connection(
@@ -349,7 +358,10 @@ impl NetworkBehaviour for Floodsub {
         _: Endpoint,
         _: PortUse,
     ) -> Result<THandler<Self>, ConnectionDenied> {
-        Ok(Default::default())
+        Ok(OneShotHandler::new(
+            SubstreamProtocol::new(FloodsubProtocol::new(self.config.max_message_len), ()),
+            OneShotHandlerConfig::default(),
+        ))
     }
 
     fn on_connection_handler_event(
@@ -460,6 +472,7 @@ impl NetworkBehaviour for Floodsub {
                         FloodsubRpc {
                             subscriptions: Vec::new(),
                             messages: vec![message.clone()],
+                            max_message_len: self.config.max_message_len,
                         },
                     ));
                 }

protocols/floodsub/src/lib.rs

@@ -23,6 +23,7 @@
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 
 use libp2p_identity::PeerId;
+use protocol::DEFAULT_MAX_MESSAGE_LEN_BYTES;
 
 pub mod protocol;
 
@@ -48,13 +49,30 @@ pub struct FloodsubConfig {
     /// `true` if messages published by local node should be propagated as messages received from
     /// the network, `false` by default.
     pub subscribe_local_messages: bool,
+
+    /// Maximum message length in bytes. Defaults to 2KiB.
+    pub max_message_len: usize,
 }
 
 impl FloodsubConfig {
     pub fn new(local_peer_id: PeerId) -> Self {
         Self {
             local_peer_id,
             subscribe_local_messages: false,
+            max_message_len: DEFAULT_MAX_MESSAGE_LEN_BYTES,
         }
     }
+
+    /// Set whether or not messages published by local node should be
+    /// propagated as messages received from the network.
+    pub fn with_subscribe_local_messages(mut self, subscribe_local_messages: bool) -> Self {
+        self.subscribe_local_messages = subscribe_local_messages;
+        self
+    }
+
+    /// Set the maximum message length in bytes.
+    pub fn with_max_message_len(mut self, max_message_len: usize) -> Self {
+        self.max_message_len = max_message_len;
+        self
+    }
 }

protocols/floodsub/src/protocol.rs

@@ -32,18 +32,29 @@ use libp2p_identity::PeerId;
 use libp2p_swarm::StreamProtocol;
 use std::{io, iter, pin::Pin};
 
-const MAX_MESSAGE_LEN_BYTES: usize = 2048;
+pub(crate) const DEFAULT_MAX_MESSAGE_LEN_BYTES: usize = 2048;
 
 const PROTOCOL_NAME: StreamProtocol = StreamProtocol::new("/floodsub/1.0.0");
 
 /// Implementation of `ConnectionUpgrade` for the floodsub protocol.
-#[derive(Debug, Clone, Default)]
-pub struct FloodsubProtocol {}
+#[derive(Debug, Clone)]
+pub struct FloodsubProtocol {
+    /// Maximum message length in bytes.
+    pub max_message_len: usize,
+}
 
 impl FloodsubProtocol {
     /// Builds a new `FloodsubProtocol`.
-    pub fn new() -> FloodsubProtocol {
-        FloodsubProtocol {}
+    pub fn new(max_message_len: usize) -> FloodsubProtocol {
+        Self { max_message_len }
+    }
+}
+
+impl Default for FloodsubProtocol {
+    fn default() -> Self {
+        Self {
+            max_message_len: DEFAULT_MAX_MESSAGE_LEN_BYTES,
+        }
     }
 }
 
@@ -68,7 +79,7 @@ where
         Box::pin(async move {
             let mut framed = Framed::new(
                 socket,
-                quick_protobuf_codec::Codec::<proto::RPC>::new(MAX_MESSAGE_LEN_BYTES),
+                quick_protobuf_codec::Codec::<proto::RPC>::new(self.max_message_len),
             );
 
             let rpc = framed
@@ -102,6 +113,7 @@ where
                         topic: Topic::new(sub.topic_id.unwrap_or_default()),
                     })
                     .collect(),
+                max_message_len: self.max_message_len,
             })
         })
     }
@@ -132,6 +144,8 @@ pub struct FloodsubRpc {
     pub messages: Vec<FloodsubMessage>,
     /// List of subscriptions.
     pub subscriptions: Vec<FloodsubSubscription>,
+    /// Maximum message length in bytes.
+    pub max_message_len: usize,
 }
 
 impl UpgradeInfo for FloodsubRpc {
@@ -155,7 +169,7 @@ where
         Box::pin(async move {
             let mut framed = Framed::new(
                 socket,
-                quick_protobuf_codec::Codec::<proto::RPC>::new(MAX_MESSAGE_LEN_BYTES),
+                quick_protobuf_codec::Codec::<proto::RPC>::new(self.max_message_len),
             );
             framed.send(self.into_rpc()).await?;
             framed.close().await?;