Version 2 transactions remain non-standard until CSV activates

Before activation, such transactions might not be mined, so don't
allow into the mempool.

- Tests: move get_bip9_status to util.py

- Test relay of version 2 transactions

Github-Pull: #7835
Rebased-From: e4ba9f6b0402cf7a2ad0d74f617c434a26c6e124 5cb1d8a2071d05beb9907a423178895fd8a5c359 da5fdbb3a2778523cce70d635c1aa2b31a693bc6

1 files changed, 8 insertions, 0 deletions

diff --git a/src/main.cpp b/src/main.cpp
index 2275a02080..f85ac33177 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1022,6 +1022,14 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState &state, const C
     if (fRequireStandard && !IsStandardTx(tx, reason))
         return state.DoS(0, false, REJECT_NONSTANDARD, reason);
 
+    // Don't relay version 2 transactions until CSV is active, and we can be
+    // sure that such transactions will be mined (unless we're on
+    // -testnet/-regtest).
+    const CChainParams& chainparams = Params();
+    if (fRequireStandard && tx.nVersion >= 2 && VersionBitsTipState(chainparams.GetConsensus(), Consensus::DEPLOYMENT_CSV) != THRESHOLD_ACTIVE) {
+        return state.DoS(0, false, REJECT_NONSTANDARD, "premature-version2-tx");
+    }
+
     // Only accept nLockTime-using transactions that can be mined in the next
     // block; we don't want our mempool filled up with transactions that can't
     // be mined yet.