fix: total difficulty logic (#260)

* fix total difficulty logic

* lints

* refactor and address comments

Author: frisitano

Cargo.lock

@@ -43,6 +43,8 @@ pub struct ScrollNetworkManager<N> {
     from_handle_rx: UnboundedReceiverStream<NetworkHandleMessage>,
     /// The scroll wire protocol manager.
     scroll_wire: ScrollWireManager,
+    /// The constant value that must be added to the block number to get the total difficulty.
+    td_constant: U128,
 }
 
 impl ScrollNetworkManager<RethNetworkHandle<ScrollNetworkPrimitives>> {
@@ -51,6 +53,7 @@ impl ScrollNetworkManager<RethNetworkHandle<ScrollNetworkPrimitives>> {
     pub async fn new<C: BlockNumReaderT + 'static>(
         mut network_config: RethNetworkConfig<C, ScrollNetworkPrimitives>,
         scroll_wire_config: ScrollWireConfig,
+        td_constant: U128,
     ) -> Self {
         // Create the scroll-wire protocol handler.
         let (scroll_wire_handler, events) = ScrollWireProtocolHandler::new(scroll_wire_config);
@@ -74,7 +77,7 @@ impl ScrollNetworkManager<RethNetworkHandle<ScrollNetworkPrimitives>> {
         // Spawn the inner network manager.
         tokio::spawn(inner_network_manager);
 
-        Self { handle, from_handle_rx: from_handle_rx.into(), scroll_wire }
+        Self { handle, from_handle_rx: from_handle_rx.into(), scroll_wire, td_constant }
     }
 }
 
@@ -83,7 +86,11 @@ impl<N: FullNetwork<Primitives = ScrollNetworkPrimitives>> ScrollNetworkManager<
     ///
     /// This is used when the scroll-wire [`ScrollWireProtocolHandler`] and the inner network
     /// manager [`RethNetworkManager`] are instantiated externally.
-    pub fn from_parts(inner_network_handle: N, events: UnboundedReceiver<ScrollWireEvent>) -> Self {
+    pub fn from_parts(
+        inner_network_handle: N,
+        events: UnboundedReceiver<ScrollWireEvent>,
+        td_constant: U128,
+    ) -> Self {
         // Create the channel for sending messages to the network manager from the network handle.
         let (to_manager_tx, from_handle_rx) = mpsc::unbounded_channel();
 
@@ -92,7 +99,7 @@ impl<N: FullNetwork<Primitives = ScrollNetworkPrimitives>> ScrollNetworkManager<
 
         let handle = ScrollNetworkHandle::new(to_manager_tx, inner_network_handle);
 
-        Self { handle, from_handle_rx: from_handle_rx.into(), scroll_wire }
+        Self { handle, from_handle_rx: from_handle_rx.into(), scroll_wire, td_constant }
     }
 
     /// Returns a new [`ScrollNetworkHandle`] instance.
@@ -119,7 +126,7 @@ impl<N: FullNetwork<Primitives = ScrollNetworkPrimitives>> ScrollNetworkManager<
             .collect();
 
         let eth_wire_new_block = {
-            let td = U128::from(block.block.header.number);
+            let td = compute_td(self.td_constant, block.block.header.number);
             let mut eth_wire_block = block.block.clone();
             eth_wire_block.header.extra_data = block.signature.clone().into();
             EthWireNewBlock { block: eth_wire_block, td }
@@ -223,3 +230,8 @@ impl<N: FullNetwork<Primitives = ScrollNetworkPrimitives>> Stream for ScrollNetw
         Poll::Pending
     }
 }
+
+/// Compute totally difficulty for a given block number.
+fn compute_td(td_constant: U128, block_number: u64) -> U128 {
+    td_constant.saturating_add(U128::from(block_number))
+}

crates/network/src/manager.rs

@@ -15,6 +15,7 @@ workspace = true
 
 [dependencies]
 # alloy
+alloy-chains.workspace = true
 alloy-primitives.workspace = true
 alloy-provider.workspace = true
 alloy-rpc-client.workspace = true
@@ -90,6 +91,7 @@ tokio.workspace = true
 tracing.workspace = true
 
 [dev-dependencies]
+alloy-chains.workspace = true
 alloy-eips.workspace = true
 futures.workspace = true
 reth-e2e-test-utils.workspace = true

crates/node/Cargo.toml

@@ -5,7 +5,8 @@ use crate::{
 };
 use std::{fs, path::PathBuf, sync::Arc, time::Duration};
 
-use alloy_primitives::{hex, Address};
+use alloy_chains::NamedChain;
+use alloy_primitives::{hex, Address, U128};
 use alloy_provider::{Provider, ProviderBuilder};
 use alloy_rpc_client::RpcClient;
 use alloy_signer::Signer;
@@ -139,9 +140,6 @@ impl ScrollRollupNodeConfig {
             "Building rollup node with config:\n{:#?}",
             self
         );
-        // Instantiate the network manager
-        let network = ctx.network;
-        let scroll_network_manager = ScrollNetworkManager::from_parts(network.clone(), events);
 
         // Get the chain spec.
         let chain_spec = ctx.chain_spec;
@@ -150,6 +148,11 @@ impl ScrollRollupNodeConfig {
         let named_chain = chain_spec.chain().named().expect("expected named chain");
         let node_config = Arc::new(NodeConfig::from_named_chain(named_chain));
 
+        // Instantiate the network manager
+        let network = ctx.network;
+        let scroll_network_manager =
+            ScrollNetworkManager::from_parts(network.clone(), events, td_constant(named_chain));
+
         // Create the engine api client.
         let engine_api = ScrollAuthApiEngineClient::new(rpc_server_handles.auth.http_client());
 
@@ -596,6 +599,15 @@ pub struct GasPriceOracleArgs {
     pub default_suggested_priority_fee: u64,
 }
 
+/// Returns the total difficulty constant for the given chain.
+const fn td_constant(chain: NamedChain) -> U128 {
+    match chain {
+        NamedChain::Scroll => constants::SCROLL_MAINNET_TD_CONSTANT,
+        NamedChain::ScrollSepolia => constants::SCROLL_SEPOLIA_TD_CONSTANT,
+        _ => U128::ZERO, // Default to zero for other chains
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/node/src/args.rs

@@ -1,5 +1,7 @@
 //! Constants related to the [`crate::ScrollRollupNode`]
 
+use alloy_primitives::U128;
+
 /// The max retries for the L1 provider.
 pub(crate) const PROVIDER_MAX_RETRIES: u32 = 10;
 
@@ -27,3 +29,11 @@ pub(crate) const DEFAULT_SUGGEST_PRIORITY_FEE: u64 = 100;
 /// Scroll default gas limit.
 /// Should match <https://github.com/scroll-tech/reth/blob/scroll/crates/scroll/node/src/builder/payload.rs#L36>.
 pub const SCROLL_GAS_LIMIT: u64 = 20_000_000;
+
+/// The constant value that must be added to the block number to get the total difficulty for Scroll
+/// mainnet.
+pub(crate) const SCROLL_MAINNET_TD_CONSTANT: U128 = U128::from_limbs([14906960, 0]);
+
+/// The constant value that must be added to the block number to get the total difficulty for Scroll
+/// Sepolia.
+pub(crate) const SCROLL_SEPOLIA_TD_CONSTANT: U128 = U128::from_limbs([8484488, 0]);

crates/node/src/constants.rs

@@ -495,8 +495,12 @@ async fn can_bridge_blocks() {
         .with_pow()
         .build_with_noop_provider(chain_spec.clone());
     let scroll_wire_config = ScrollWireConfig::new(true);
-    let mut scroll_network =
-        scroll_network::ScrollNetworkManager::new(network_config, scroll_wire_config).await;
+    let mut scroll_network = scroll_network::ScrollNetworkManager::new(
+        network_config,
+        scroll_wire_config,
+        Default::default(),
+    )
+    .await;
     let scroll_network_handle = scroll_network.handle();
 
     // Connect the scroll-wire node to the scroll NetworkManager.