MOVEONLY: check that fees > direct conflicts to policy/rbf

1 files changed, 2 insertions, 24 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index 710fe2d873..b0403bffd2 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -782,30 +782,8 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
     if (fReplacementTransaction)
     {
         CFeeRate newFeeRate(nModifiedFees, nSize);
-        for (const auto& mi : setIterConflicting) {
-            // Don't allow the replacement to reduce the feerate of the
-            // mempool.
-            //
-            // We usually don't want to accept replacements with lower
-            // feerates than what they replaced as that would lower the
-            // feerate of the next block. Requiring that the feerate always
-            // be increased is also an easy-to-reason about way to prevent
-            // DoS attacks via replacements.
-            //
-            // We only consider the feerates of transactions being directly
-            // replaced, not their indirect descendants. While that does
-            // mean high feerate children are ignored when deciding whether
-            // or not to replace, we do require the replacement to pay more
-            // overall fees too, mitigating most cases.
-            CFeeRate oldFeeRate(mi->GetModifiedFee(), mi->GetTxSize());
-            if (newFeeRate <= oldFeeRate)
-            {
-                return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee",
-                        strprintf("rejecting replacement %s; new feerate %s <= old feerate %s",
-                            hash.ToString(),
-                            newFeeRate.ToString(),
-                            oldFeeRate.ToString()));
-            }
+        if (const auto err_string{PaysMoreThanConflicts(setIterConflicting, newFeeRate, hash)}) {
+            return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee", *err_string);
         }
 
         // Calculate all conflicting entries and enforce Rule #5.