Move download_sender_certificates_for_receiver to proxy

linera-base/Cargo.toml

@@ -51,8 +51,8 @@ linera-kywasmtime = { workspace = true, optional = true }
 linera-witty = { workspace = true, features = ["macros"] }
 lru.workspace = true
 prometheus = { workspace = true, optional = true }
-quick_cache.workspace = true
 proptest = { workspace = true, optional = true, features = ["alloc"] }
+quick_cache.workspace = true
 rand.workspace = true
 reqwest = { workspace = true, optional = true }
 serde = { workspace = true, features = ["rc"] }

linera-core/Cargo.toml

@@ -67,10 +67,10 @@ linera-storage.workspace = true
 linera-version.workspace = true
 linera-views.workspace = true
 lru.workspace = true
-quick_cache.workspace = true
 papaya = { workspace = true, features = ["serde"] }
 prometheus = { workspace = true, optional = true }
 proptest = { workspace = true, optional = true }
+quick_cache.workspace = true
 rand = { workspace = true, features = ["std_rng"] }
 serde.workspace = true
 serde_json.workspace = true

linera-core/src/chain_worker/actor.rs

@@ -17,6 +17,7 @@ use linera_base::{
     hashed::Hashed,
     identifiers::{ApplicationId, BlobId, ChainId, StreamId},
     time::Instant,
+    value_cache::{ParkingCache, ValueCache},
 };
 use linera_chain::{
     data_types::{BlockProposal, MessageBundle, ProposedBlock},
@@ -32,8 +33,6 @@ use linera_views::context::InactiveContext;
 use tokio::sync::{mpsc, oneshot, OwnedRwLockReadGuard};
 use tracing::{debug, instrument, trace, Instrument as _};
 
-use linera_base::value_cache::{ParkingCache, ValueCache};
-
 use super::{config::ChainWorkerConfig, state::ChainWorkerState, DeliveryNotifier};
 use crate::{
     chain_worker::BlockOutcome,

linera-core/src/chain_worker/state.rs

@@ -20,6 +20,7 @@ use linera_base::{
     ensure,
     hashed::Hashed,
     identifiers::{AccountOwner, ApplicationId, BlobId, BlobType, ChainId, EventId, StreamId},
+    value_cache::{ParkingCache, ValueCache},
 };
 use linera_chain::{
     data_types::{
@@ -43,8 +44,6 @@ use linera_views::{
 use tokio::sync::{oneshot, OwnedRwLockReadGuard, RwLock, RwLockWriteGuard};
 use tracing::{debug, instrument, trace, warn};
 
-use linera_base::value_cache::{ParkingCache, ValueCache};
-
 use super::{ChainWorkerConfig, ChainWorkerRequest, DeliveryNotifier, EventSubscriptionsResult};
 use crate::{
     data_types::{ChainInfo, ChainInfoQuery, ChainInfoResponse, CrossChainRequest},
@@ -590,7 +589,8 @@ where
             for block in blocks {
                 let hashed_block = block.into_inner();
                 let height = hashed_block.inner().header.height;
-                self.block_values.insert_hashed(Cow::Owned(hashed_block.clone()));
+                self.block_values
+                    .insert_hashed(Cow::Owned(hashed_block.clone()));
                 height_to_blocks.insert(height, hashed_block);
             }
         }
@@ -1458,8 +1458,7 @@ where
                     .query_application(context, query, self.service_runtime_endpoint.as_mut())
                     .await
                     .with_execution_context(ChainExecutionContext::Query)?;
-                self.execution_state_cache
-                    .insert(&requested_block, state);
+                self.execution_state_cache.insert(&requested_block, state);
                 Ok(outcome)
             } else {
                 tracing::debug!(requested_block = %requested_block, "requested block hash not found in cache, querying committed state");

linera-core/src/client/mod.rs

@@ -1207,63 +1207,40 @@ impl<Env: Environment> Client<Env> {
             .get(&sender_chain_id)
             .copied()
             .unwrap_or(BlockHeight::ZERO);
-        let (max_epoch, committees) = self.admin_committees().await?;
-
-        // Recursively collect all certificates we need, following
-        // the chain of previous_message_blocks back to next_outbox_height.
-        let mut certificates = BTreeMap::new();
-        let mut current_height = height;
 
-        // Stop if we've reached the height we've already processed.
-        while current_height >= next_outbox_height {
-            // Download the certificate for this height.
-            let downloaded = self
-                .requests_scheduler
-                .download_certificates_by_heights(
-                    remote_node,
-                    sender_chain_id,
-                    vec![current_height],
-                )
-                .await?;
-            let Some(certificate) = downloaded.into_iter().next() else {
-                return Err(chain_client::Error::CannotDownloadMissingSenderBlock {
-                    chain_id: sender_chain_id,
-                    height: current_height,
-                });
-            };
+        // Skip if we already have all certificates up to this height.
+        if height < next_outbox_height {
+            return Ok(());
+        }
 
-            // Validate the certificate.
-            Client::<Env>::check_certificate(max_epoch, &committees, &certificate)?
-                .into_result()?;
+        let (max_epoch, committees) = self.admin_committees().await?;
 
-            // Check if there's a previous message block to our chain.
-            let block = certificate.block();
-            let next_height = block
-                .body
-                .previous_message_blocks
-                .get(&receiver_chain_id)
-                .map(|(_prev_hash, prev_height)| *prev_height);
-
-            // Store this certificate.
-            certificates.insert(current_height, certificate);
-
-            if let Some(prev_height) = next_height {
-                // Continue with the previous block.
-                current_height = prev_height;
-            } else {
-                // No more dependencies.
-                break;
-            }
-        }
+        // Request the proxy to do the traversal and return the certificates
+        // in ascending height order, ready for processing.
+        let certificates = self
+            .requests_scheduler
+            .download_sender_certificates_for_receiver(
+                remote_node,
+                sender_chain_id,
+                receiver_chain_id,
+                height,
+                next_outbox_height,
+            )
+            .await?;
 
         if certificates.is_empty() {
             self.local_node
                 .retry_pending_cross_chain_requests(sender_chain_id)
                 .await?;
+            return Ok(());
         }
 
-        // Process certificates in ascending block height order (BTreeMap keeps them sorted).
-        for certificate in certificates.into_values() {
+        // Process certificates in ascending block height order (already sorted by proxy).
+        for certificate in certificates {
+            // Validate the certificate.
+            Client::<Env>::check_certificate(max_epoch, &committees, &certificate)?
+                .into_result()?;
+
             self.receive_sender_certificate(
                 certificate,
                 ReceiveCertificateMode::AlreadyChecked,

linera-core/src/client/requests_scheduler/request.rs

@@ -19,6 +19,13 @@ pub enum RequestKey {
         chain_id: ChainId,
         heights: Vec<BlockHeight>,
     },
+    /// Download sender certificates for a receiver chain
+    SenderCertificates {
+        sender_chain_id: ChainId,
+        receiver_chain_id: ChainId,
+        target_height: BlockHeight,
+        start_height: BlockHeight,
+    },
     /// Download a blob by ID
     Blob(BlobId),
     /// Download a pending blob
@@ -32,6 +39,9 @@ impl RequestKey {
     pub(super) fn chain_id(&self) -> Option<ChainId> {
         match self {
             RequestKey::Certificates { chain_id, .. } => Some(*chain_id),
+            RequestKey::SenderCertificates {
+                sender_chain_id, ..
+            } => Some(*sender_chain_id),
             RequestKey::PendingBlob { chain_id, .. } => Some(*chain_id),
             _ => None,
         }

linera-core/src/client/requests_scheduler/scheduler.rs

@@ -396,6 +396,35 @@ impl<Env: Environment> RequestsScheduler<Env> {
         .await
     }
 
+    pub async fn download_sender_certificates_for_receiver(
+        &self,
+        peer: &RemoteNode<Env::ValidatorNode>,
+        sender_chain_id: ChainId,
+        receiver_chain_id: ChainId,
+        target_height: BlockHeight,
+        start_height: BlockHeight,
+    ) -> Result<Vec<ConfirmedBlockCertificate>, NodeError> {
+        self.with_peer(
+            RequestKey::SenderCertificates {
+                sender_chain_id,
+                receiver_chain_id,
+                target_height,
+                start_height,
+            },
+            peer.clone(),
+            move |peer| async move {
+                peer.download_sender_certificates_for_receiver(
+                    sender_chain_id,
+                    receiver_chain_id,
+                    target_height,
+                    start_height,
+                )
+                .await
+            },
+        )
+        .await
+    }
+
     pub async fn download_certificate_for_blob(
         &self,
         peer: &RemoteNode<Env::ValidatorNode>,

linera-core/src/data_types.rs

@@ -347,6 +347,22 @@ pub struct CertificatesByHeightRequest {
     pub heights: Vec<BlockHeight>,
 }
 
+/// Request for downloading sender certificates with their sending ancestors.
+/// The proxy will traverse `previous_message_blocks` to find all certificates
+/// that sent messages to the receiver chain.
+#[derive(Debug, Clone)]
+pub struct SenderCertificatesRequest {
+    /// The chain that sent the messages.
+    pub sender_chain_id: ChainId,
+    /// The chain that receives the messages.
+    pub receiver_chain_id: ChainId,
+    /// The target block height to start from.
+    pub target_height: BlockHeight,
+    /// The height from which to stop traversing (exclusive lower bound).
+    /// This is typically the `next_outbox_height` the client already has.
+    pub start_height: BlockHeight,
+}
+
 /// The outcome of trying to commit a list of operations to the chain.
 #[derive(Debug)]
 pub enum ClientOutcome<T> {

linera-core/src/node.rs

@@ -156,6 +156,19 @@ pub trait ValidatorNode {
         heights: Vec<BlockHeight>,
     ) -> Result<Vec<ConfirmedBlockCertificate>, NodeError>;
 
+    /// Downloads sender certificates with their sending ancestors.
+    /// The proxy traverses `previous_message_blocks` to find all certificates
+    /// from `sender_chain_id` that sent messages to `receiver_chain_id`,
+    /// starting from `target_height` and stopping at `start_height`.
+    /// Returns certificates in ascending height order, ready for processing.
+    async fn download_sender_certificates_for_receiver(
+        &self,
+        sender_chain_id: ChainId,
+        receiver_chain_id: ChainId,
+        target_height: BlockHeight,
+        start_height: BlockHeight,
+    ) -> Result<Vec<ConfirmedBlockCertificate>, NodeError>;
+
     /// Returns the hash of the `Certificate` that last used a blob.
     async fn blob_last_used_by(&self, blob_id: BlobId) -> Result<CryptoHash, NodeError>;
 

linera-core/src/remote_node.rs

@@ -266,6 +266,43 @@ impl<N: ValidatorNode> RemoteNode<N> {
         Ok(certificates)
     }
 
+    /// Downloads sender certificates with their sending ancestors.
+    #[instrument(level = "trace")]
+    pub async fn download_sender_certificates_for_receiver(
+        &self,
+        sender_chain_id: ChainId,
+        receiver_chain_id: ChainId,
+        target_height: BlockHeight,
+        start_height: BlockHeight,
+    ) -> Result<Vec<ConfirmedBlockCertificate>, NodeError> {
+        let certificates = self
+            .node
+            .download_sender_certificates_for_receiver(
+                sender_chain_id,
+                receiver_chain_id,
+                target_height,
+                start_height,
+            )
+            .await?;
+
+        // Validate that all returned certificates are for the sender chain
+        // and in ascending height order.
+        let mut prev_height = None;
+        for certificate in &certificates {
+            ensure!(
+                certificate.inner().chain_id() == sender_chain_id,
+                NodeError::UnexpectedCertificateValue
+            );
+            let height = certificate.inner().height();
+            if let Some(prev) = prev_height {
+                ensure!(height > prev, NodeError::UnexpectedCertificateValue);
+            }
+            prev_height = Some(height);
+        }
+
+        Ok(certificates)
+    }
+
     /// Checks that requesting these blobs when trying to handle this certificate is legitimate,
     /// i.e. that there are no duplicates and the blobs are actually required.
     pub fn check_blobs_not_found<T: CertificateValue>(