P2pService: Make max_response_size in PostcardCodec a u64

CHANGELOG.md

@@ -38,6 +38,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [2429](https://github.com/FuelLabs/fuel-core/pull/2429): Introduce custom enum for representing result of running service tasks
 - [2377](https://github.com/FuelLabs/fuel-core/pull/2377): Add more errors that can be returned as responses when using protocol `/fuel/req_res/0.0.2`. The errors supported are `ProtocolV1EmptyResponse` (status code `0`) for converting empty responses sent via protocol `/fuel/req_res/0.0.1`, `RequestedRangeTooLarge`(status code `1`) if the client requests a range of objects such as sealed block headers or transactions too large, `Timeout` (status code `2`) if the remote peer takes too long to fulfill a request, or `SyncProcessorOutOfCapacity` if the remote peer is fulfilling too many requests concurrently.
 - [2388](https://github.com/FuelLabs/fuel-core/pull/2388): Rework the P2P service codecs to avoid unnecessary coupling between components. The refactoring makes it explicit that the Gossipsub and RequestResponse codecs only share encoding/decoding functionalities from the Postcard codec. It also makes handling Gossipsub and RequestResponse messages completely independent of each other.
+- [2460](https://github.com/FuelLabs/fuel-core/pull/2460): The type of the `max_response_size`for the postcard codec used in `RequestResponse` protocols has been changed from `usize` to `u64`.
 
 #### Breaking
 - [2389](https://github.com/FuelLabs/fuel-core/pull/2258): Updated the `messageProof` GraphQL schema to return a non-nullable `MessageProof`.

crates/services/p2p/src/codecs/postcard.rs

@@ -14,7 +14,7 @@ use std::{
 pub struct PostcardCodec;
 
 impl RequestResponseMessageHandler<PostcardCodec> {
-    pub fn new(max_block_size: usize) -> Self {
+    pub fn new(max_block_size: u64) -> Self {
         assert_ne!(
             max_block_size, 0,
             "RequestResponseMessageHandler does not support zero block size"

crates/services/p2p/src/codecs/request_response.rs

@@ -30,9 +30,7 @@ pub struct RequestResponseMessageHandler<Codec> {
     /// Used for `max_size` parameter when reading Response Message
     /// Necessary in order to avoid DoS attacks
     /// Currently the size mostly depends on the max size of the Block
-    // TODO: https://github.com/FuelLabs/fuel-core/issues/2459.
-    // Make this a u64 instead of usize.
-    pub(crate) max_response_size: usize,
+    pub(crate) max_response_size: u64,
 }
 
 /// Since Postcard does not support async reads or writes out of the box

crates/services/p2p/src/service.rs

@@ -828,7 +828,7 @@ where
             broadcast.reserved_peers_broadcast.clone(),
             config,
             GossipsubMessageHandler::new(),
-            RequestResponseMessageHandler::new(max_block_size),
+            RequestResponseMessageHandler::new(max_block_size.try_into()?),
         )
         .await?;
         p2p_service.update_block_height(last_height);