From 776c76eb3a2fadf89f28af739c79c9fe5117f5b5 Mon Sep 17 00:00:00 2001
From: sakridge <sakridge@gmail.com>
Date: Thu, 16 Sep 2021 16:12:26 +0300
Subject: [PATCH] Only allow votes when root distance gets too high #2

Updates from master
---
 core/src/banking_stage.rs | 38 +++++++++++++++++++++++++++++++++++---
 core/src/replay_stage.rs  |  9 ++++++++-
 runtime/src/bank.rs       |  2 +-
 3 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/core/src/banking_stage.rs b/core/src/banking_stage.rs
index f3662fa0b59e0e..e5c51e9529f1ab 100644
--- a/core/src/banking_stage.rs
+++ b/core/src/banking_stage.rs
@@ -50,7 +50,6 @@ use solana_sdk::{
 use solana_transaction_status::token_balances::{
     collect_token_balances, TransactionTokenBalancesSet,
 };
-use solana_vote_program::vote_transaction;
 use std::{
     borrow::Cow,
     cmp,
@@ -1033,7 +1032,7 @@ impl BankingStage {
             .filter_map(|tx_index| {
                 let p = &msgs.packets[*tx_index];
                 let tx: Transaction = limited_deserialize(&p.data[0..p.meta.size]).ok()?;
-                if votes_only && vote_transaction::parse_vote_transaction(&tx).is_none() {
+                if votes_only && !solana_runtime::bank::is_simple_vote_transaction(&tx) {
                     return None;
                 }
                 tx.verify_precompiles(libsecp256k1_0_5_upgrade_enabled)
@@ -1174,7 +1173,7 @@ impl BankingStage {
             msgs,
             &transaction_indexes,
             bank.libsecp256k1_0_5_upgrade_enabled(),
-            false,
+            bank.vote_only_bank(),
         );
 
         let tx_count = transaction_to_packet_indexes.len();
@@ -2914,4 +2913,37 @@ mod tests {
             transaction.message_data()
         );
     }
+
+    #[test]
+    fn test_transactions_from_packets() {
+        use solana_vote_program::vote_state::Vote;
+        solana_logger::setup();
+        let mut vote_packet = Packet::default();
+        let vote_instruction = solana_vote_program::vote_instruction::vote(
+            &Pubkey::new_unique(),
+            &Pubkey::new_unique(),
+            Vote::default(),
+        );
+        let vote_transaction =
+            Transaction::new_with_payer(&[vote_instruction], Some(&Pubkey::new_unique()));
+        Packet::populate_packet(&mut vote_packet, None, &vote_transaction).unwrap();
+        let mut non_vote = Packet::default();
+        let tx = system_transaction::transfer(
+            &Keypair::new(),
+            &Pubkey::new_unique(),
+            2,
+            Hash::default(),
+        );
+        Packet::populate_packet(&mut non_vote, None, &tx).unwrap();
+        let msgs = Packets::new(vec![non_vote, vote_packet]);
+        let packet_indexes = [0, 1];
+        let (transactions, _transaction_to_packet_indexes) =
+            BankingStage::transactions_from_packets(&msgs, &packet_indexes, false, true);
+        assert_eq!(transactions.len(), 1);
+        assert!(!transactions[0].transaction().signatures.is_empty());
+
+        let (transactions, _transaction_to_packet_indexes) =
+            BankingStage::transactions_from_packets(&msgs, &packet_indexes, false, false);
+        assert_eq!(transactions.len(), 2);
+    }
 }
diff --git a/core/src/replay_stage.rs b/core/src/replay_stage.rs
index 5ab1cd3ed207d3..b115fd451eccf2 100644
--- a/core/src/replay_stage.rs
+++ b/core/src/replay_stage.rs
@@ -1228,6 +1228,13 @@ impl ReplayStage {
             );
 
             let root_distance = poh_slot - root_slot;
+            const MAX_ROOT_DISTANCE_FOR_VOTE_ONLY: Slot = 500;
+            let vote_only_bank = if root_distance > MAX_ROOT_DISTANCE_FOR_VOTE_ONLY {
+                datapoint_info!("vote-only-bank", ("slot", poh_slot, i64));
+                true
+            } else {
+                false
+            };
 
             let tpu_bank = Self::new_bank_from_parent_with_notify(
                 &parent,
@@ -1235,7 +1242,7 @@ impl ReplayStage {
                 root_slot,
                 my_pubkey,
                 rpc_subscriptions,
-                root_distance > 500,
+                vote_only_bank,
             );
 
             let tpu_bank = bank_forks.write().unwrap().insert(tpu_bank);
diff --git a/runtime/src/bank.rs b/runtime/src/bank.rs
index a0506ec422c6c0..d6d6f0e4db4ac2 100644
--- a/runtime/src/bank.rs
+++ b/runtime/src/bank.rs
@@ -5150,7 +5150,7 @@ pub fn goto_end_of_slot(bank: &mut Bank) {
     }
 }
 
-fn is_simple_vote_transaction(transaction: &Transaction) -> bool {
+pub fn is_simple_vote_transaction(transaction: &Transaction) -> bool {
     if transaction.message.instructions.len() == 1 {
         let instruction = &transaction.message.instructions[0];
         let program_pubkey =