feat(beacon-network): add json-rpc method to get the latest finalized…

… root (ethereum#1364)

trin-beacon/Cargo.toml

@@ -11,6 +11,7 @@ description = "Beacon network subprotocol for Trin."
 authors = ["https://github.com/ethereum/trin/graphs/contributors"]
 
 [dependencies]
+alloy-primitives = "0.7.0"
 anyhow = "1.0.68"
 chrono = "0.4.38"
 discv5 = { version = "0.4.1", features = ["serde"] }
@@ -30,6 +31,8 @@ trin-metrics = { path = "../trin-metrics" }
 trin-storage = { path = "../trin-storage" }
 trin-validation = { path = "../trin-validation" }
 utp-rs = { git = "https://github.com/ethereum/utp", tag = "v0.1.0-alpha.13" }
+mockall = "0.13.0"
+mockall_double = "0.3.1"
 
 [dev-dependencies]
 serde_yaml = "0.9.33"

trin-beacon/src/lib.rs

@@ -10,8 +10,8 @@ mod sync;
 mod test_utils;
 pub mod validation;
 
+use mockall_double::double;
 use std::sync::Arc;
-
 use tokio::{
     sync::{broadcast, mpsc, RwLock},
     task::JoinHandle,

trin-beacon/src/network.rs

@@ -1,6 +1,5 @@
-use std::sync::Arc;
-
 use parking_lot::RwLock as PLRwLock;
+use std::sync::Arc;
 use tokio::sync::{Mutex, RwLock};
 use tracing::error;
 use utp_rs::socket::UtpSocket;

trin-beacon/src/validation.rs

@@ -1,8 +1,6 @@
+use alloy_primitives::B256;
 use anyhow::anyhow;
 use chrono::Duration;
-use ssz::Decode;
-use std::sync::Arc;
-
 use ethportal_api::{
     consensus::fork::ForkName,
     types::content_value::beacon::{
@@ -13,9 +11,13 @@ use ethportal_api::{
     BeaconContentKey,
 };
 use light_client::consensus::rpc::portal_rpc::expected_current_slot;
+use mockall_double::double;
+use ssz::{Decode, Encode};
+use std::sync::Arc;
 use tokio::sync::RwLock;
 
 use trin_validation::{
+    merkle::proof::verify_merkle_proof,
     oracle::HeaderOracle,
     validator::{ValidationResult, Validator},
 };
@@ -157,7 +159,34 @@ impl Validator<BeaconContentKey> for BeaconValidator {
                     ));
                 }
 
-                // TODO: Validate the historical summaries with proof against current state root
+                // Verify the historical summaries against the latest finalized state root
+                let latest_finalized_root = self
+                    .header_oracle
+                    .read()
+                    .await
+                    .get_finalized_state_root()
+                    .await?;
+                let historical_summaries_state_proof = fork_versioned_historical_summaries
+                    .historical_summaries_with_proof
+                    .proof;
+                let historical_summaries_root = fork_versioned_historical_summaries
+                    .historical_summaries_with_proof
+                    .historical_summaries
+                    .as_ssz_bytes();
+                let historical_summaries_root = B256::try_from(&historical_summaries_root[..])
+                    .map_err(|err| anyhow!("Invalid historical summaries root: {:?}", err))?;
+
+                if !verify_merkle_proof(
+                    historical_summaries_root,
+                    &historical_summaries_state_proof,
+                    5,
+                    59, // 31 + 28 = 59
+                    latest_finalized_root,
+                ) {
+                    return Err(anyhow!(
+                        "Merkle proof validation failed for HistoricalSummariesProof"
+                    ));
+                }
             }
         }
 
@@ -347,11 +376,16 @@ mod tests {
             "Light client optimistic update is not from the recent fork. Expected deneb, got capella"
         );
     }
+
     #[tokio::test]
     async fn test_validate_historical_summaries_with_proof() {
-        let validator = BeaconValidator {
-            header_oracle: Arc::new(RwLock::new(HeaderOracle::default())),
-        };
+        let mut mock_oracle = MockHeaderOracle::new();
+        mock_oracle
+            .expect_get_finalized_state_root()
+            .returning(|| Ok(B256::from_slice(&[0x12, 0x34])));
+        let header_oracle = Arc::new(RwLock::new(mock_oracle));
+        let validator = BeaconValidator { header_oracle };
+
         let summaries_with_proof = test_utils::get_history_summaries_with_proof();
         let content = summaries_with_proof.as_ssz_bytes();
         let content_key =

trin-validation/Cargo.toml

@@ -26,6 +26,7 @@ ssz_types = { git = "https://github.com/KolbyML/ssz_types.git", rev = "2a5922de7
 tokio = { version = "1.14.0", features = ["full"] }
 tree_hash = { git = "https://github.com/KolbyML/tree_hash.git", rev = "8aaf8bb4184148768d48e2cfbbdd0b95d1da8730" }
 tree_hash_derive = { git = "https://github.com/KolbyML/tree_hash.git", rev = "8aaf8bb4184148768d48e2cfbbdd0b95d1da8730" }
+mockall = "0.13.0"
 
 [dev-dependencies]
 alloy-rlp = "0.3.4"

trin-validation/src/oracle.rs

@@ -1,6 +1,7 @@
 use alloy_primitives::B256;
 use anyhow::anyhow;
 use enr::NodeId;
+use mockall::{automock, mock};
 use serde_json::Value;
 use tokio::sync::mpsc;
 
@@ -177,6 +178,24 @@ impl HeaderOracle {
 
         Ok(enr)
     }
+
+    /// Return latest finalized root of the beacon state.
+    pub async fn get_finalized_state_root(&self) -> anyhow::Result<B256> {
+        let endpoint = BeaconEndpoint::FinalizedStateRoot;
+        let (resp, mut resp_rx) = mpsc::unbounded_channel::<Result<Value, String>>();
+        let request = BeaconJsonRpcRequest { endpoint, resp };
+        let tx = self.beacon_jsonrpc_tx()?;
+        tx.send(request)?;
+
+        let state_root = match resp_rx.recv().await {
+            Some(val) => val.map_err(|err| anyhow!("Beacon network request error: {err:?}"))?,
+            None => return Err(anyhow!("No response from Beacon network")),
+        };
+
+        let state_root: B256 = serde_json::from_value(state_root)?;
+
+        Ok(state_root)
+    }
 }
 
 #[cfg(test)]