From f2187780d21630bd922c0ae214c921d8f7d9f522 Mon Sep 17 00:00:00 2001
From: Pankaj Garg <pankaj@solana.com>
Date: Thu, 18 Apr 2019 11:18:49 -0700
Subject: [PATCH] Do not forward vote transactions (#3871)

---
 core/src/banking_stage.rs | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/core/src/banking_stage.rs b/core/src/banking_stage.rs
index 389c16c4e0..ffdaa0cae2 100644
--- a/core/src/banking_stage.rs
+++ b/core/src/banking_stage.rs
@@ -84,10 +84,11 @@ impl BankingStage {
         // Many banks that process transactions in parallel.
         let bank_thread_hdls: Vec<JoinHandle<()>> = (0..num_threads)
             .map(|i| {
-                let verified_receiver = if i < num_threads - 1 {
-                    verified_receiver.clone()
+                let (verified_receiver, enable_forwarding) = if i < num_threads - 1 {
+                    (verified_receiver.clone(), true)
                 } else {
-                    verified_vote_receiver.clone()
+                    // Disable forwarding of vote transactions, as votes are gossiped
+                    (verified_vote_receiver.clone(), false)
                 };
 
                 let poh_recorder = poh_recorder.clone();
@@ -102,6 +103,7 @@ impl BankingStage {
                             &poh_recorder,
                             &cluster_info,
                             &mut recv_start,
+                            enable_forwarding,
                         );
                         exit.store(true, Ordering::Relaxed);
                     })
@@ -205,6 +207,7 @@ impl BankingStage {
         poh_recorder: &Arc<Mutex<PohRecorder>>,
         cluster_info: &Arc<RwLock<ClusterInfo>>,
         buffered_packets: &[(Packets, usize, Vec<u8>)],
+        enable_forwarding: bool,
     ) -> Result<UnprocessedPackets> {
         let rcluster_info = cluster_info.read().unwrap();
 
@@ -219,11 +222,13 @@ impl BankingStage {
                 Self::process_buffered_packets(poh_recorder, buffered_packets)
             }
             BufferedPacketsDecision::Forward => {
-                let _ = Self::forward_unprocessed_packets(
-                    &socket,
-                    &rcluster_info.leader_data().unwrap().tpu_via_blobs,
-                    &buffered_packets,
-                );
+                if enable_forwarding {
+                    let _ = Self::forward_unprocessed_packets(
+                        &socket,
+                        &rcluster_info.leader_data().unwrap().tpu_via_blobs,
+                        &buffered_packets,
+                    );
+                }
                 Ok(vec![])
             }
             _ => Ok(buffered_packets.to_vec()),
@@ -256,6 +261,7 @@ impl BankingStage {
         poh_recorder: &Arc<Mutex<PohRecorder>>,
         cluster_info: &Arc<RwLock<ClusterInfo>>,
         recv_start: &mut Instant,
+        enable_forwarding: bool,
     ) {
         let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
         let mut buffered_packets = vec![];
@@ -266,6 +272,7 @@ impl BankingStage {
                     poh_recorder,
                     cluster_info,
                     &buffered_packets,
+                    enable_forwarding,
                 )
                 .map(|packets| buffered_packets = packets)
                 .unwrap_or_else(|_| buffered_packets.clear());
@@ -295,12 +302,14 @@ impl BankingStage {
                         continue;
                     }
 
-                    if let Some(leader) = cluster_info.read().unwrap().leader_data() {
-                        let _ = Self::forward_unprocessed_packets(
-                            &socket,
-                            &leader.tpu_via_blobs,
-                            &unprocessed_packets,
-                        );
+                    if enable_forwarding {
+                        if let Some(leader) = cluster_info.read().unwrap().leader_data() {
+                            let _ = Self::forward_unprocessed_packets(
+                                &socket,
+                                &leader.tpu_via_blobs,
+                                &unprocessed_packets,
+                            );
+                        }
                     }
                 }
                 Err(err) => {