tx fees, policy: do not read estimates of old fee_estimates.dat

Old fee estimates could cause transactions to become stuck in the
mempool. This commit prevents the node from using stale estimates
from an old file.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/policy/fees.h b/src/policy/fees.h
index a6c45839b9..a348ba05d8 100644
--- a/src/policy/fees.h
+++ b/src/policy/fees.h
@@ -25,6 +25,11 @@
 // How often to flush fee estimates to fee_estimates.dat.
 static constexpr std::chrono::hours FEE_FLUSH_INTERVAL{1};
 
+/** fee_estimates.dat that are more than 60 hours (2.5 days) will not be read,
+ * as the estimates in the file are stale.
+ */
+static constexpr std::chrono::hours MAX_FILE_AGE{60};
+
 class AutoFile;
 class CTxMemPoolEntry;
 class TxConfirmStats;
@@ -248,6 +253,9 @@ public:
     void FlushFeeEstimates()
         EXCLUSIVE_LOCKS_REQUIRED(!m_cs_fee_estimator);
 
+    /** Calculates the age of the file, since last modified */
+    std::chrono::hours GetFeeEstimatorFileAge();
+
 private:
     mutable Mutex m_cs_fee_estimator;