handle more p2p requests + alt blocks

Cargo.lock

@@ -531,6 +531,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags 2.5.0",
  "bytemuck",
+ "bytes",
  "cuprate-database",
  "cuprate-database-service",
  "cuprate-helper",

binaries/cuprated/Cargo.toml

@@ -23,7 +23,7 @@ cuprate-p2p-core         = { path = "../../p2p/p2p-core" }
 cuprate-dandelion-tower  = { path = "../../p2p/dandelion-tower" }
 cuprate-async-buffer     = { path = "../../p2p/async-buffer" }
 cuprate-address-book     = { path = "../../p2p/address-book" }
-cuprate-blockchain       = { path = "../../storage/blockchain" }
+cuprate-blockchain       = { path = "../../storage/blockchain", features = ["service"] }
 cuprate-database-service = { path = "../../storage/service" }
 cuprate-txpool           = { path = "../../storage/txpool" }
 cuprate-database         = { path = "../../storage/database" }

binaries/cuprated/src/blockchain/manager.rs

@@ -1,17 +1,27 @@
 mod batch_handler;
+mod handler;
 
-use crate::blockchain::manager::batch_handler::handle_incoming_block_batch;
 use crate::blockchain::types::ConsensusBlockchainReadHandle;
 use cuprate_blockchain::service::{BlockchainReadHandle, BlockchainWriteHandle};
-use cuprate_consensus::{BlockChainContextService, BlockVerifierService, TxVerifierService};
+use cuprate_consensus::context::RawBlockChainContext;
+use cuprate_consensus::{
+    BlockChainContextRequest, BlockChainContextResponse, BlockChainContextService,
+    BlockVerifierService, ExtendedConsensusError, TxVerifierService, VerifyBlockRequest,
+    VerifyBlockResponse, VerifyTxRequest, VerifyTxResponse,
+};
 use cuprate_p2p::block_downloader::BlockBatch;
+use cuprate_types::blockchain::{BlockchainReadRequest, BlockchainResponse};
+use cuprate_types::Chain;
 use futures::StreamExt;
 use tokio::sync::mpsc::Receiver;
+use tower::{Service, ServiceExt};
+use tracing::error;
 
 pub struct BlockchainManager {
     blockchain_write_handle: BlockchainWriteHandle,
     blockchain_read_handle: BlockchainReadHandle,
     blockchain_context_service: BlockChainContextService,
+    cached_blockchain_context: RawBlockChainContext,
     block_verifier_service: BlockVerifierService<
         BlockChainContextService,
         TxVerifierService<ConsensusBlockchainReadHandle>,
@@ -34,20 +44,86 @@ impl BlockchainManager {
             blockchain_write_handle,
             blockchain_read_handle,
             blockchain_context_service,
+            cached_blockchain_context: todo!(),
             block_verifier_service,
         }
     }
 
+    async fn handle_incoming_main_chain_batch(
+        &mut self,
+        batch: BlockBatch,
+    ) -> Result<(), anyhow::Error> {
+        let VerifyBlockResponse::MainChainBatchPrepped(prepped) = self
+            .block_verifier_service
+            .ready()
+            .await
+            .expect("TODO")
+            .call(VerifyBlockRequest::MainChainBatchPrepareBlocks {
+                blocks: batch.blocks,
+            })
+            .await?
+        else {
+            panic!("Incorrect response!");
+        };
+
+        for (block, txs) in prepped {
+            let VerifyBlockResponse::MainChain(verified_block) = block_verifier_service
+                .ready()
+                .await
+                .expect("TODO")
+                .call(VerifyBlockRequest::MainChainPrepped { block, txs })
+                .await
+                .unwrap()
+            else {
+                panic!("Incorrect response!");
+            };
+
+            blockchain_context_service
+                .ready()
+                .await
+                .expect("TODO")
+                .call(BlockChainContextRequest::Update(NewBlockData {
+                    block_hash: verified_block.block_hash,
+                    height: verified_block.height,
+                    timestamp: verified_block.block.header.timestamp,
+                    weight: verified_block.weight,
+                    long_term_weight: verified_block.long_term_weight,
+                    generated_coins: verified_block.generated_coins,
+                    vote: HardFork::from_vote(verified_block.block.header.hardfork_signal),
+                    cumulative_difficulty: verified_block.cumulative_difficulty,
+                }))
+                .await
+                .expect("TODO");
+
+            blockchain_write_handle
+                .ready()
+                .await
+                .expect("TODO")
+                .call(BlockchainWriteRequest::WriteBlock(verified_block))
+                .await
+                .expect("TODO");
+        }
+    }
+
+    async fn handle_incoming_block_batch(&mut self, batch: BlockBatch) {
+        let (first_block, _) = batch
+            .blocks
+            .first()
+            .expect("Block batch should not be empty");
+
+        if first_block.header.previous == self.cached_blockchain_context.top_hash {
+            todo!("Main chain")
+        } else {
+            todo!("Alt chain")
+        }
+    }
+
     pub async fn run(mut self, mut batch_rx: Receiver<BlockBatch>) {
         loop {
             tokio::select! {
                 Some(batch) = batch_rx.recv() => {
-                    handle_incoming_block_batch(
+                    self.handle_incoming_block_batch(
                         batch,
-                        &mut self.block_verifier_service,
-                        &mut self.blockchain_context_service,
-                        &mut self.blockchain_read_handle,
-                        &mut self.blockchain_write_handle
                     ).await;
                 }
                 else => {

binaries/cuprated/src/blockchain/manager/batch_handler.rs

@@ -3,6 +3,7 @@
 use crate::blockchain::types::ConsensusBlockchainReadHandle;
 use cuprate_blockchain::service::{BlockchainReadHandle, BlockchainWriteHandle};
 use cuprate_consensus::context::NewBlockData;
+use cuprate_consensus::transactions::new_tx_verification_data;
 use cuprate_consensus::{
     BlockChainContextRequest, BlockChainContextResponse, BlockChainContextService,
     BlockVerifierService, BlockchainReadRequest, BlockchainResponse, ExtendedConsensusError,
@@ -11,82 +12,17 @@ use cuprate_consensus::{
 use cuprate_p2p::block_downloader::BlockBatch;
 use cuprate_types::blockchain::BlockchainWriteRequest;
 use cuprate_types::{Chain, HardFork};
+use rayon::prelude::*;
 use tower::{Service, ServiceExt};
 use tracing::{debug, error, info};
 
-pub async fn handle_incoming_block_batch<C, TxV>(
-    batch: BlockBatch,
-    block_verifier_service: &mut BlockVerifierService<C, TxV, ConsensusBlockchainReadHandle>,
-    blockchain_context_service: &mut C,
-    blockchain_read_handle: &mut BlockchainReadHandle,
-    blockchain_write_handle: &mut BlockchainWriteHandle,
-) where
-    C: Service<
-            BlockChainContextRequest,
-            Response = BlockChainContextResponse,
-            Error = tower::BoxError,
-        > + Clone
-        + Send
-        + 'static,
-    C::Future: Send + 'static,
-
-    TxV: Service<VerifyTxRequest, Response = VerifyTxResponse, Error = ExtendedConsensusError>
-        + Clone
-        + Send
-        + 'static,
-    TxV::Future: Send + 'static,
-{
-    let (first_block, _) = batch
-        .blocks
-        .first()
-        .expect("Block batch should not be empty");
-
-    handle_incoming_block_batch_main_chain(
-        batch,
-        block_verifier_service,
-        blockchain_context_service,
-        blockchain_write_handle,
-    )
-    .await;
-
-    // TODO: alt block to the DB
-    /*
-    match blockchain_read_handle
-        .oneshot(BlockchainReadRequest::FindBlock(
-            first_block.header.previous,
-        ))
-        .await
-    {
-        Err(_) | Ok(BlockchainResponse::FindBlock(None)) => {
-            // The block downloader shouldn't be downloading orphan blocks
-            error!("Failed to find parent block for first block in batch.");
-            return;
-        }
-        Ok(BlockchainResponse::FindBlock(Some((chain, _)))) => match chain {
-            Chain::Main => {
-                handle_incoming_block_batch_main_chain(
-                    batch,
-                    block_verifier_service,
-                    blockchain_context_service,
-                    blockchain_write_handle,
-                )
-                .await;
-            }
-            Chain::Alt(_) => todo!(),
-        },
-
-        Ok(_) => panic!("Blockchain service returned incorrect response"),
-    }
-
-     */
-}
-
 async fn handle_incoming_block_batch_main_chain<C, TxV>(
     batch: BlockBatch,
     block_verifier_service: &mut BlockVerifierService<C, TxV, ConsensusBlockchainReadHandle>,
     blockchain_context_service: &mut C,
     blockchain_write_handle: &mut BlockchainWriteHandle,
-) where
+) -> Result<(), anyhow::Error>
+where
     C: Service<
             BlockChainContextRequest,
             Response = BlockChainContextResponse,
@@ -114,8 +50,7 @@ async fn handle_incoming_block_batch_main_chain<C, TxV>(
         .call(VerifyBlockRequest::MainChainBatchPrepareBlocks {
             blocks: batch.blocks,
         })
-        .await
-        .unwrap()
+        .await?
     else {
         panic!("Incorrect response!");
     };
@@ -126,8 +61,7 @@ async fn handle_incoming_block_batch_main_chain<C, TxV>(
             .await
             .expect("TODO")
             .call(VerifyBlockRequest::MainChainPrepped { block, txs })
-            .await
-            .unwrap()
+            .await?
         else {
             panic!("Incorrect response!");
         };
@@ -158,3 +92,30 @@ async fn handle_incoming_block_batch_main_chain<C, TxV>(
             .expect("TODO");
     }
 }
+
+async fn handle_incoming_block_batch_alt_chain<C, TxV>(
+    batch: BlockBatch,
+    block_verifier_service: &mut BlockVerifierService<C, TxV, ConsensusBlockchainReadHandle>,
+    blockchain_context_service: &mut C,
+    blockchain_write_handle: &mut BlockchainWriteHandle,
+) -> Result<(), anyhow::Error>
+where
+    C: Service<
+            BlockChainContextRequest,
+            Response = BlockChainContextResponse,
+            Error = tower::BoxError,
+        > + Clone
+        + Send
+        + 'static,
+    C::Future: Send + 'static,
+
+    TxV: Service<VerifyTxRequest, Response = VerifyTxResponse, Error = ExtendedConsensusError>
+        + Clone
+        + Send
+        + 'static,
+    TxV::Future: Send + 'static,
+{
+    for (block, txs) in batch.blocks {
+        alt_block_info.cumulative_difficulty
+    }
+}

binaries/cuprated/src/blockchain/manager/handler.rs

@@ -0,0 +1,163 @@
+use crate::blockchain::types::ConsensusBlockchainReadHandle;
+use cuprate_blockchain::service::{BlockchainReadHandle, BlockchainWriteHandle};
+use cuprate_consensus::transactions::new_tx_verification_data;
+use cuprate_consensus::{
+    BlockChainContextRequest, BlockChainContextResponse, BlockVerifierService,
+    ExtendedConsensusError, VerifyBlockRequest, VerifyBlockResponse, VerifyTxRequest,
+    VerifyTxResponse,
+};
+use cuprate_p2p::block_downloader::BlockBatch;
+use cuprate_types::blockchain::{
+    BlockchainReadRequest, BlockchainResponse, BlockchainWriteRequest,
+};
+use cuprate_types::AltBlockInformation;
+use monero_serai::block::Block;
+use monero_serai::transaction::Transaction;
+use rayon::prelude::*;
+use tower::{Service, ServiceExt};
+
+async fn handle_incoming_alt_block<C, TxV>(
+    block: Block,
+    txs: Vec<Transaction>,
+    current_cumulative_difficulty: u128,
+    block_verifier_service: &mut BlockVerifierService<C, TxV, ConsensusBlockchainReadHandle>,
+    blockchain_context_service: &mut C,
+    blockchain_write_handle: &mut BlockchainWriteHandle,
+) -> Result<(), anyhow::Error>
+where
+    C: Service<
+            BlockChainContextRequest,
+            Response = BlockChainContextResponse,
+            Error = tower::BoxError,
+        > + Clone
+        + Send
+        + 'static,
+    C::Future: Send + 'static,
+
+    TxV: Service<VerifyTxRequest, Response = VerifyTxResponse, Error = ExtendedConsensusError>
+        + Clone
+        + Send
+        + 'static,
+    TxV::Future: Send + 'static,
+{
+    let prepared_txs = txs
+        .into_par_iter()
+        .map(|tx| {
+            let tx = new_tx_verification_data(tx)?;
+            (tx.tx_hash, tx)
+        })
+        .collect::<Result<_, _>>()?;
+
+    let VerifyBlockResponse::AltChain(alt_block_info) = block_verifier_service
+        .ready()
+        .await
+        .expect("TODO")
+        .call(VerifyBlockRequest::AltChain {
+            block,
+            prepared_txs,
+        })
+        .await?
+    else {
+        panic!("Incorrect response!");
+    };
+
+    if alt_block_info.cumulative_difficulty > current_cumulative_difficulty {
+        todo!("do re-org");
+    }
+
+    blockchain_write_handle
+        .ready()
+        .await
+        .expect("TODO")
+        .call(BlockchainWriteRequest::WriteAltBlock(alt_block_info))?;
+
+    Ok(())
+}
+
+async fn try_do_reorg<C, TxV>(
+    top_alt_block: AltBlockInformation,
+    chain_height: usize,
+    block_verifier_service: &mut BlockVerifierService<C, TxV, ConsensusBlockchainReadHandle>,
+    blockchain_context_service: &mut C,
+    blockchain_write_handle: &mut BlockchainWriteHandle,
+    blockchain_read_handle: &mut BlockchainReadHandle,
+) -> Result<(), anyhow::Error>
+where
+    C: Service<
+            BlockChainContextRequest,
+            Response = BlockChainContextResponse,
+            Error = tower::BoxError,
+        > + Clone
+        + Send
+        + 'static,
+    C::Future: Send + 'static,
+
+    TxV: Service<VerifyTxRequest, Response = VerifyTxResponse, Error = ExtendedConsensusError>
+        + Clone
+        + Send
+        + 'static,
+    TxV::Future: Send + 'static,
+{
+    let BlockchainResponse::AltBlocksInChain(mut alt_blocks) = blockchain_read_handle
+        .ready()
+        .await
+        .expect("TODO")
+        .call(BlockchainReadRequest::AltBlocksInChain(
+            top_alt_block.chain_id,
+        ))
+        .await?
+    else {
+        panic!("Incorrect response!");
+    };
+
+    alt_blocks.push(top_alt_block);
+
+    let split_height = alt_blocks[0].height;
+
+    let BlockchainResponse::PopBlocks(old_main_chain_id) = blockchain_write_handle
+        .ready()
+        .await
+        .expect("TODO")
+        .call(BlockchainWriteRequest::PopBlocks(
+            chain_height - split_height + 1,
+        ))
+        .await?
+    else {
+        panic!("Incorrect response!");
+    };
+
+    todo!()
+}
+
+async fn verify_add_alt_blocks_to_main_chain<C, TxV>(
+    alt_blocks: Vec<AltBlockInformation>,
+    block_verifier_service: &mut BlockVerifierService<C, TxV, ConsensusBlockchainReadHandle>,
+    blockchain_context_service: &mut C,
+    blockchain_write_handle: &mut BlockchainWriteHandle,
+) -> Result<(), anyhow::Error>
+where
+    C: Service<
+            BlockChainContextRequest,
+            Response = BlockChainContextResponse,
+            Error = tower::BoxError,
+        > + Clone
+        + Send
+        + 'static,
+    C::Future: Send + 'static,
+
+    TxV: Service<VerifyTxRequest, Response = VerifyTxResponse, Error = ExtendedConsensusError>
+        + Clone
+        + Send
+        + 'static,
+    TxV::Future: Send + 'static,
+{
+    let VerifyBlockResponse::AltChain(alt_block_info) = block_verifier_service
+        .ready()
+        .await
+        .expect("TODO")
+        .call(VerifyBlockRequest::MainChainPrepped { block, txs })
+        .await?
+    else {
+        panic!("Incorrect response!");
+    };
+}

binaries/cuprated/src/main.rs

@@ -42,7 +42,9 @@ fn main() {
                 .unwrap();
 
         let net = cuprate_p2p::initialize_network(
-            p2p::request_handler::P2pProtocolRequestHandler,
+            p2p::request_handler::P2pProtocolRequestHandler {
+                blockchain_read_handle: bc_read_handle.clone(),
+            },
             p2p::core_sync_svc::CoreSyncService(context_svc.clone()),
             config.clearnet_config(),
         )

binaries/cuprated/src/p2p/request_handler.rs

@@ -1,12 +1,23 @@
+use bytes::Bytes;
 use cuprate_p2p_core::{ProtocolRequest, ProtocolResponse};
 use futures::future::BoxFuture;
 use futures::FutureExt;
 use std::task::{Context, Poll};
-use tower::Service;
+use tower::{Service, ServiceExt};
 use tracing::trace;
 
+use cuprate_blockchain::service::BlockchainReadHandle;
+use cuprate_helper::cast::usize_to_u64;
+use cuprate_helper::map::split_u128_into_low_high_bits;
+use cuprate_p2p::constants::{MAX_BLOCKCHAIN_SUPPLEMENT_LEN, MAX_BLOCK_BATCH_LEN};
+use cuprate_types::blockchain::{BlockchainReadRequest, BlockchainResponse};
+use cuprate_types::BlockCompleteEntry;
+use cuprate_wire::protocol::{ChainRequest, ChainResponse, GetObjectsRequest, GetObjectsResponse};
+
 #[derive(Clone)]
-pub struct P2pProtocolRequestHandler;
+pub struct P2pProtocolRequestHandler {
+    pub(crate) blockchain_read_handle: BlockchainReadHandle,
+}
 
 impl Service<ProtocolRequest> for P2pProtocolRequestHandler {
     type Response = ProtocolResponse;
@@ -19,15 +30,98 @@ impl Service<ProtocolRequest> for P2pProtocolRequestHandler {
 
     fn call(&mut self, req: ProtocolRequest) -> Self::Future {
         match req {
-            ProtocolRequest::GetObjects(_) => trace!("TODO: GetObjects"),
-            ProtocolRequest::GetChain(_) => trace!("TODO: GetChain"),
-            ProtocolRequest::FluffyMissingTxs(_) => trace!("TODO: FluffyMissingTxs"),
-            ProtocolRequest::GetTxPoolCompliment(_) => trace!("TODO: GetTxPoolCompliment"),
-            ProtocolRequest::NewBlock(_) => trace!("TODO: NewBlock"),
-            ProtocolRequest::NewFluffyBlock(_) => trace!("TODO: NewFluffyBlock"),
-            ProtocolRequest::NewTransactions(_) => trace!("TODO: NewTransactions"),
+            ProtocolRequest::GetObjects(req) => {
+                get_objects(self.blockchain_read_handle.clone(), req).boxed()
+            }
+            ProtocolRequest::GetChain(req) => {
+                get_chain(self.blockchain_read_handle.clone(), req).boxed()
+            }
+            ProtocolRequest::FluffyMissingTxs(_) => async { Ok(ProtocolResponse::NA) }.boxed(),
+            ProtocolRequest::GetTxPoolCompliment(_) => async { Ok(ProtocolResponse::NA) }.boxed(),
+            ProtocolRequest::NewBlock(_) => async { Ok(ProtocolResponse::NA) }.boxed(),
+            ProtocolRequest::NewFluffyBlock(_) => async { Ok(ProtocolResponse::NA) }.boxed(),
+            ProtocolRequest::NewTransactions(_) => async { Ok(ProtocolResponse::NA) }.boxed(),
         }
-
-        async { Ok(ProtocolResponse::NA) }.boxed()
     }
 }
+
+async fn get_objects(
+    blockchain_read_handle: BlockchainReadHandle,
+    req: GetObjectsRequest,
+) -> Result<ProtocolResponse, tower::BoxError> {
+    if req.blocks.is_empty() {
+        Err("No blocks requested in a GetObjectsRequest")?;
+    }
+
+    if req.blocks.len() > MAX_BLOCK_BATCH_LEN {
+        Err("Too many blocks requested in a GetObjectsRequest")?;
+    }
+
+    let block_ids: Vec<[u8; 32]> = (&req.blocks).into();
+    // de-allocate the backing [`Bytes`]
+    drop(req);
+
+    let res = blockchain_read_handle
+        .oneshot(BlockchainReadRequest::BlockCompleteEntries(block_ids))
+        .await?;
+
+    let BlockchainResponse::BlockCompleteEntries {
+        blocks,
+        missed_ids,
+        current_blockchain_height,
+    } = res
+    else {
+        panic!("Blockchain service returned wrong response!");
+    };
+
+    Ok(ProtocolResponse::GetObjects(GetObjectsResponse {
+        blocks,
+        missed_ids: missed_ids.into(),
+        current_blockchain_height: usize_to_u64(current_blockchain_height),
+    }))
+}
+
+async fn get_chain(
+    blockchain_read_handle: BlockchainReadHandle,
+    req: ChainRequest,
+) -> Result<ProtocolResponse, tower::BoxError> {
+    if req.block_ids.is_empty() {
+        Err("No block hashes sent in a `ChainRequest`")?;
+    }
+
+    if req.block_ids.len() > MAX_BLOCKCHAIN_SUPPLEMENT_LEN {
+        Err("Too many block hashes in a `ChainRequest`")?;
+    }
+
+    let block_ids: Vec<[u8; 32]> = (&req.block_ids).into();
+    // de-allocate the backing [`Bytes`]
+    drop(req);
+
+    let res = blockchain_read_handle
+        .oneshot(BlockchainReadRequest::NextMissingChainEntry(block_ids))
+        .await?;
+
+    let BlockchainResponse::NextMissingChainEntry {
+        next_entry,
+        first_missing_block,
+        start_height,
+        chain_height,
+        cumulative_difficulty,
+    } = res
+    else {
+        panic!("Blockchain service returned wrong response!");
+    };
+
+    let (cumulative_difficulty_low64, cumulative_difficulty_top64) =
+        split_u128_into_low_high_bits(cumulative_difficulty);
+
+    Ok(ProtocolResponse::GetChain(ChainResponse {
+        start_height: usize_to_u64(start_height),
+        total_height: usize_to_u64(chain_height),
+        cumulative_difficulty_low64,
+        cumulative_difficulty_top64,
+        m_block_ids: next_entry.into(),
+        m_block_weights: vec![],
+        first_block: first_missing_block.map_or(Bytes::new(), Bytes::from),
+    }))
+}

consensus/src/block.rs

@@ -8,6 +8,7 @@ use std::{
 };
 
 use futures::FutureExt;
+use monero_serai::generators::H;
 use monero_serai::{
     block::Block,
     transaction::{Input, Transaction},
@@ -183,6 +184,19 @@ impl PreparedBlock {
             block: block.block,
         })
     }
+
+    pub fn new_alt_block(block: AltBlockInformation) -> Result<PreparedBlock, ConsensusError> {
+        Ok(PreparedBlock {
+            block_blob: block.block_blob,
+            hf_vote: HardFork::from_version(block.block.header.hardfork_version)
+                .map_err(|_| BlockError::HardForkError(HardForkError::HardForkUnknown))?,
+            hf_version: HardFork::from_vote(block.block.header.hardfork_signal),
+            block_hash: block.block_hash,
+            pow_hash: block.pow_hash,
+            miner_tx_weight: block.block.miner_transaction.weight(),
+            block: block.block,
+        })
+    }
 }
 
 /// A request to verify a block.

p2p/address-book/src/lib.rs

@@ -88,14 +88,19 @@ mod sealed {
 
     /// An internal trait for the address book for a [`NetworkZone`] that adds the requirement of [`borsh`] traits
     /// onto the network address.
-    pub trait BorshNetworkZone: NetworkZone<Addr = Self::BorshAddr> {
-        type BorshAddr: NetZoneAddress + borsh::BorshDeserialize + borsh::BorshSerialize;
+    pub trait BorshNetworkZone:
+        NetworkZone<
+        Addr: NetZoneAddress<BanID: borsh::BorshDeserialize + borsh::BorshSerialize>
+                  + borsh::BorshDeserialize
+                  + borsh::BorshSerialize,
+    >
+    {
     }
 
     impl<T: NetworkZone> BorshNetworkZone for T
     where
         T::Addr: borsh::BorshDeserialize + borsh::BorshSerialize,
+        <T::Addr as NetZoneAddress>::BanID: borsh::BorshDeserialize + borsh::BorshSerialize,
     {
-        type BorshAddr = T::Addr;
     }
 }

p2p/p2p/src/constants.rs

@@ -46,7 +46,12 @@ pub(crate) const INITIAL_CHAIN_REQUESTS_TO_SEND: usize = 3;
 /// The enforced maximum amount of blocks to request in a batch.
 ///
 /// Requesting more than this will cause the peer to disconnect and potentially lead to bans.
-pub(crate) const MAX_BLOCK_BATCH_LEN: usize = 100;
+pub const MAX_BLOCK_BATCH_LEN: usize = 100;
+
+/// The enforced maximum amount of block hashes in a blockchain supplement request.
+///
+/// Requesting more than this might cause the peer to disconnect and potentially lead to bans.
+pub const MAX_BLOCKCHAIN_SUPPLEMENT_LEN: usize = 250;
 
 /// The timeout that the block downloader will use for requests.
 pub(crate) const BLOCK_DOWNLOADER_REQUEST_TIMEOUT: Duration = Duration::from_secs(30);

p2p/p2p/src/lib.rs

@@ -26,7 +26,7 @@ mod broadcast;
 mod client_pool;
 pub mod config;
 pub mod connection_maintainer;
-mod constants;
+pub mod constants;
 mod inbound_server;
 mod sync_states;
 

storage/blockchain/Cargo.toml

@@ -38,6 +38,7 @@ serde            = { workspace = true, optional = true }
 tower        = { workspace = true }
 thread_local = { workspace = true, optional = true }
 rayon        = { workspace = true, optional = true }
+bytes = "1.6.0"
 
 [dev-dependencies]
 cuprate-helper     = { path = "../../helper", features = ["thread", "cast"] }

storage/blockchain/src/ops/block.rs

@@ -2,20 +2,23 @@
 
 //---------------------------------------------------------------------------------------------------- Import
 use bytemuck::TransparentWrapper;
-use monero_serai::block::{Block, BlockHeader};
+use bytes::Bytes;
 
 use cuprate_database::{
-    RuntimeError, StorableVec, {DatabaseRo, DatabaseRw},
+    RuntimeError, StorableVec, {DatabaseIter, DatabaseRo, DatabaseRw},
 };
+use cuprate_helper::cast::usize_to_u64;
 use cuprate_helper::{
     map::{combine_low_high_bits_to_u128, split_u128_into_low_high_bits},
     tx_utils::tx_fee,
 };
 use cuprate_types::{
-    AltBlockInformation, ChainId, ExtendedBlockHeader, HardFork, VerifiedBlockInformation,
-    VerifiedTransactionInformation,
+    AltBlockInformation, BlockCompleteEntry, ChainId, ExtendedBlockHeader, HardFork,
+    TransactionBlobs, VerifiedBlockInformation, VerifiedTransactionInformation,
 };
+use monero_serai::block::{Block, BlockHeader};
 
+use crate::tables::TablesIter;
 use crate::{
     ops::{
         alt_block,
@@ -256,6 +259,40 @@ pub fn get_block_extended_header_top(
     Ok((header, height))
 }
 
+//---------------------------------------------------------------------------------------------------- `get_block_complete_entry`
+
+pub fn get_block_complete_entry(
+    block_hash: &BlockHash,
+    tables: &impl TablesIter,
+) -> Result<BlockCompleteEntry, RuntimeError> {
+    let height = tables.block_heights().get(block_hash)?;
+
+    let block_blob = tables.block_blobs().get(&height)?.0;
+
+    let block = Block::read(&mut block_blob.as_slice()).expect("Valid block failed to be read");
+
+    let txs = if let Some(first_tx) = block.transactions.first() {
+        let first_tx_idx = tables.tx_ids().get(first_tx)?;
+        let end_tx_idx = first_tx_idx + usize_to_u64(block.transactions.len());
+
+        let tx_blobs = tables.tx_blobs_iter().get_range(first_tx_idx..end_tx_idx)?;
+
+        tx_blobs
+            .map(|res| Ok(Bytes::from(res?.0)))
+            .collect::<Result<_, RuntimeError>>()?
+    } else {
+        vec![]
+    };
+
+    Ok(BlockCompleteEntry {
+        block: Bytes::from(block_blob),
+        txs: TransactionBlobs::Normal(txs),
+        pruned: false,
+        // This is only needed when pruned.
+        block_weight: 0,
+    })
+}
+
 //---------------------------------------------------------------------------------------------------- Misc
 /// Retrieve a [`BlockInfo`] via its [`BlockHeight`].
 #[doc = doc_error!()]

storage/blockchain/src/service/read.rs

@@ -1,19 +1,20 @@
 //! Database reader thread-pool definitions and logic.
 
 //---------------------------------------------------------------------------------------------------- Import
+use rayon::{
+    iter::{Either, IntoParallelIterator, ParallelIterator},
+    prelude::*,
+    ThreadPool,
+};
+use std::cmp::min;
+use std::ops::Index;
 use std::{
     collections::{HashMap, HashSet},
     sync::Arc,
 };
-
-use rayon::{
-    iter::{IntoParallelIterator, ParallelIterator},
-    prelude::*,
-    ThreadPool,
-};
 use thread_local::ThreadLocal;
 
-use cuprate_database::{ConcreteEnv, DatabaseRo, Env, EnvInner, RuntimeError};
+use cuprate_database::{ConcreteEnv, DatabaseIter, DatabaseRo, Env, EnvInner, RuntimeError};
 use cuprate_database_service::{init_thread_pool, DatabaseReadService, ReaderThreads};
 use cuprate_helper::map::combine_low_high_bits_to_u128;
 use cuprate_types::{
@@ -21,6 +22,8 @@ use cuprate_types::{
     Chain, ChainId, ExtendedBlockHeader, OutputOnChain,
 };
 
+use crate::ops::block::get_block_complete_entry;
+use crate::tables::{BlockBlobs, TxIds};
 use crate::{
     ops::{
         alt_block::{
@@ -92,6 +95,7 @@ fn map_request(
     /* SOMEDAY: pre-request handling, run some code for each request? */
 
     match request {
+        R::BlockCompleteEntries(blocks) => block_complete_entries(env, blocks),
         R::BlockExtendedHeader(block) => block_extended_header(env, block),
         R::BlockHash(block, chain) => block_hash(env, block, chain),
         R::FindBlock(block_hash) => find_block(env, block_hash),
@@ -106,6 +110,7 @@ fn map_request(
         R::KeyImagesSpent(set) => key_images_spent(env, set),
         R::CompactChainHistory => compact_chain_history(env),
         R::FindFirstUnknown(block_ids) => find_first_unknown(env, &block_ids),
+        R::NextMissingChainEntry(block_hashes) => next_missing_chain_entry(env, block_hashes),
         R::AltBlocksInChain(chain_id) => alt_blocks_in_chain(env, chain_id),
     }
 
@@ -180,9 +185,41 @@ macro_rules! get_tables {
 // FIXME: implement multi-transaction read atomicity.
 // <https://github.com/Cuprate/cuprate/pull/113#discussion_r1576874589>.
 
-// TODO: The overhead of parallelism may be too much for every request, perfomace test to find optimal
+// TODO: The overhead of parallelism may be too much for every request, performance test to find optimal
 // amount of parallelism.
 
+/// [`BlockchainReadRequest::BlockCompleteEntries`].
+fn block_complete_entries(env: &ConcreteEnv, block_hashes: Vec<BlockHash>) -> ResponseResult {
+    // Prepare tx/tables in `ThreadLocal`.
+    let env_inner = env.env_inner();
+    let tx_ro = thread_local(env);
+    let tables = thread_local(env);
+
+    let (missed_ids, blocks) = block_hashes
+        .into_par_iter()
+        .map(|block_hash| {
+            let tx_ro = tx_ro.get_or_try(|| env_inner.tx_ro())?;
+            let tables = get_tables!(env_inner, tx_ro, tables)?.as_ref();
+
+            match get_block_complete_entry(&block_hash, tables) {
+                Err(RuntimeError::KeyNotFound) => Ok(Either::Left(block_hash)),
+                res => res.map(Either::Right),
+            }
+        })
+        .collect::<Result<_, _>>()?;
+
+    let tx_ro = tx_ro.get_or_try(|| env_inner.tx_ro())?;
+    let tables = get_tables!(env_inner, tx_ro, tables)?.as_ref();
+
+    let chain_height = crate::ops::blockchain::chain_height(tables.block_heights())?;
+
+    Ok(BlockchainResponse::BlockCompleteEntries {
+        blocks,
+        missed_ids,
+        current_blockchain_height: chain_height,
+    })
+}
+
 /// [`BlockchainReadRequest::BlockExtendedHeader`].
 #[inline]
 fn block_extended_header(env: &ConcreteEnv, block_height: BlockHeight) -> ResponseResult {
@@ -556,6 +593,62 @@ fn find_first_unknown(env: &ConcreteEnv, block_ids: &[BlockHash]) -> ResponseRes
     })
 }
 
+/// [`BlockchainReadRequest::NextMissingChainEntry`]
+fn next_missing_chain_entry(env: &ConcreteEnv, block_hashes: Vec<[u8; 32]>) -> ResponseResult {
+    let env_inner = env.env_inner();
+    let tx_ro = env_inner.tx_ro()?;
+
+    let table_block_heights = env_inner.open_db_ro::<BlockHeights>(&tx_ro)?;
+    let table_block_infos = env_inner.open_db_ro::<BlockInfos>(&tx_ro)?;
+
+    let (top_block_height, top_block_info) = table_block_infos.last()?;
+
+    let mut start_height = 0;
+
+    for block_hash in block_hashes {
+        match table_block_heights.get(&block_hash) {
+            Ok(height) => {
+                start_height = height;
+                break;
+            }
+            Err(RuntimeError::KeyNotFound) => continue,
+            Err(e) => return Err(e),
+        }
+    }
+
+    let table_block_infos = env_inner.open_db_ro::<BlockInfos>(&tx_ro)?;
+
+    const DEFAULT_CHAIN_ENTRY_SIZE: usize = 10_000;
+
+    let end_height = min(
+        start_height + DEFAULT_CHAIN_ENTRY_SIZE,
+        top_block_height + 1,
+    );
+
+    let block_hashes: Vec<_> = table_block_infos
+        .get_range(start_height..end_height)?
+        .map(|block_info| Ok(block_info?.block_hash))
+        .collect::<Result<_, _>>()?;
+
+    let first_missing_block = if block_hashes.len() > 1 {
+        let table_block_blobs = env_inner.open_db_ro::<BlockBlobs>(&tx_ro)?;
+        Some(table_block_blobs.get(&(start_height + 1))?.0)
+    } else {
+        None
+    };
+
+    Ok(BlockchainResponse::NextMissingChainEntry {
+        next_entry: block_hashes,
+        first_missing_block,
+        start_height,
+        chain_height: top_block_height + 1,
+        cumulative_difficulty: combine_low_high_bits_to_u128(
+            top_block_info.cumulative_difficulty_low,
+            top_block_info.cumulative_difficulty_high,
+        ),
+    })
+}
+
 /// [`BlockchainReadRequest::AltBlocksInChain`]
 fn alt_blocks_in_chain(env: &ConcreteEnv, chain_id: ChainId) -> ResponseResult {
     // Prepare tx/tables in `ThreadLocal`.

types/src/blockchain.rs

@@ -11,7 +11,7 @@ use std::{
 
 use crate::{
     types::{Chain, ExtendedBlockHeader, OutputOnChain, VerifiedBlockInformation},
-    AltBlockInformation, ChainId,
+    AltBlockInformation, BlockCompleteEntry, ChainId,
 };
 
 //---------------------------------------------------------------------------------------------------- ReadRequest
@@ -25,6 +25,11 @@ use crate::{
 /// See `Response` for the expected responses per `Request`.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum BlockchainReadRequest {
+    /// Request for [`BlockCompleteEntry`]s.
+    ///
+    /// The input is the hashes of the blocks wanted.
+    BlockCompleteEntries(Vec<[u8; 32]>),
+
     /// Request a block's extended header.
     ///
     /// The input is the block's height.
@@ -101,6 +106,13 @@ pub enum BlockchainReadRequest {
     /// order, or else the returned response is unspecified and meaningless,
     /// as this request performs a binary search.
     FindFirstUnknown(Vec<[u8; 32]>),
+
+    /// A request for the next missing chain entry.
+    ///
+    /// The input is a list of block hashes in reverse chronological order that do not necessarily
+    /// directly follow each other.
+    NextMissingChainEntry(Vec<[u8; 32]>),
+
     /// A request for all alt blocks in the chain with the given [`ChainId`].
     AltBlocksInChain(ChainId),
 }
@@ -145,6 +157,16 @@ pub enum BlockchainWriteRequest {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum BlockchainResponse {
     //------------------------------------------------------ Reads
+    /// Response to [`BlockchainReadRequest::BlockCompleteEntries`]
+    BlockCompleteEntries {
+        /// The blocks requested that we had.
+        blocks: Vec<BlockCompleteEntry>,
+        /// The hashes of the blocks we did not have.
+        missed_ids: Vec<[u8; 32]>,
+        /// The current height of our blockchain.
+        current_blockchain_height: usize,
+    },
+
     /// Response to [`BlockchainReadRequest::BlockExtendedHeader`].
     ///
     /// Inner value is the extended headed of the requested block.
@@ -218,6 +240,24 @@ pub enum BlockchainResponse {
     /// This will be [`None`] if all blocks were known.
     FindFirstUnknown(Option<(usize, usize)>),
 
+    /// The response for [`BlockchainReadRequest::NextMissingChainEntry`]
+    NextMissingChainEntry {
+        /// A list of block hashes that should be next from the requested chain.
+        ///
+        /// The first block hash will overlap with one of the blocks in the request.
+        next_entry: Vec<[u8; 32]>,
+        /// The block blob of the second block in `next_entry`.
+        ///
+        /// If there is only 1 block in `next_entry` then this will be [`None`].
+        first_missing_block: Option<Vec<u8>>,
+        /// The height of the first block in `next_entry`.
+        start_height: usize,
+        /// The current height of our chain.
+        chain_height: usize,
+        /// The cumulative difficulty of our chain.
+        cumulative_difficulty: u128,
+    },
+
     /// The response for [`BlockchainReadRequest::AltBlocksInChain`].
     ///
     /// Contains all the alt blocks in the alt-chain in chronological order.