From 250cdeeae8a24758b219afdaab321644fef943be Mon Sep 17 00:00:00 2001
From: parazyd <parazyd@dyne.org>
Date: Sat, 30 Apr 2022 20:50:17 +0200
Subject: [PATCH] consensus/proto/tx: Don't act on state transitions if the tx
 is known.

---
 src/blockchain/txstore.rs          |  5 +++++
 src/consensus/proto/protocol_tx.rs | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/blockchain/txstore.rs b/src/blockchain/txstore.rs
index 53b36e0ad..e9c07fe0f 100644
--- a/src/blockchain/txstore.rs
+++ b/src/blockchain/txstore.rs
@@ -35,6 +35,11 @@ impl TxStore {
         Ok(ret)
     }
 
+    /// Check if the txstore contains a given transaction.
+    pub fn contains(&self, txid: blake3::Hash) -> Result<bool> {
+        Ok(self.0.contains_key(txid.as_bytes())?)
+    }
+
     /// Fetch requested transactions from the txstore. The `strict` param
     /// will make the function fail if a transaction has not been found.
     pub fn get(&self, tx_hashes: &[blake3::Hash], strict: bool) -> Result<Vec<Option<Tx>>> {
diff --git a/src/consensus/proto/protocol_tx.rs b/src/consensus/proto/protocol_tx.rs
index 92b46f536..eee6e46dc 100644
--- a/src/consensus/proto/protocol_tx.rs
+++ b/src/consensus/proto/protocol_tx.rs
@@ -10,6 +10,7 @@ use crate::{
         ProtocolJobsManager, ProtocolJobsManagerPtr,
     },
     node::MemoryState,
+    util::serial::serialize,
     Result,
 };
 
@@ -54,6 +55,21 @@ impl ProtocolTx {
             debug!("ProtocolTx::handle_receive_tx() recv: {:?}", tx);
 
             let tx_copy = (*tx).clone();
+            let tx_hash = blake3::hash(&serialize(&tx_copy));
+
+            let tx_in_txstore =
+                match self.state.read().await.blockchain.transactions.contains(tx_hash) {
+                    Ok(v) => v,
+                    Err(e) => {
+                        error!("handle_receive_tx(): Failed querying txstore: {}", e);
+                        continue
+                    }
+                };
+
+            if self.state.read().await.unconfirmed_txs.contains(&tx_copy) || tx_in_txstore {
+                debug!("ProtocolTx::handle_receive_tx(): We have already seen this tx.");
+                continue
+            }
 
             debug!("ProtocolTx::handle_receive_tx(): Starting state transition validation");
             let canon_state_clone = self.state.read().await.state_machine.lock().await.clone();