Introduce MAX_BIP125_RBF_SEQUENCE constant

src/bitcoin-tx.cpp

@@ -13,6 +13,7 @@
 #include "core_io.h"
 #include "keystore.h"
 #include "policy/policy.h"
+#include "policy/rbf.h"
 #include "primitives/transaction.h"
 #include "script/script.h"
 #include "script/sign.h"
@@ -215,7 +216,7 @@ static void MutateTxRBFOptIn(CMutableTransaction& tx, const std::string& strInId
     int cnt = 0;
     for (CTxIn& txin : tx.vin) {
         if (strInIdx == "" || cnt == inIdx) {
-            txin.nSequence = std::numeric_limits<unsigned int>::max() - 2;
+            txin.nSequence = MAX_BIP125_RBF_SEQUENCE;
         }
         ++cnt;
     }

src/policy/rbf.h

@@ -7,6 +7,8 @@
 
 #include "txmempool.h"
 
+static const uint32_t MAX_BIP125_RBF_SEQUENCE = 0xfffffffd;
+
 enum RBFTransactionState {
     RBF_TRANSACTIONSTATE_UNKNOWN,
     RBF_TRANSACTIONSTATE_REPLACEABLE_BIP125,

src/rpc/rawtransaction.cpp

@@ -14,6 +14,7 @@
 #include "merkleblock.h"
 #include "net.h"
 #include "policy/policy.h"
+#include "policy/rbf.h"
 #include "primitives/transaction.h"
 #include "rpc/server.h"
 #include "script/script.h"
@@ -359,7 +360,7 @@ UniValue createrawtransaction(const JSONRPCRequest& request)
 
         uint32_t nSequence;
         if (rbfOptIn) {
-            nSequence = std::numeric_limits<uint32_t>::max() - 2;
+            nSequence = MAX_BIP125_RBF_SEQUENCE;
         } else if (rawTx.nLockTime) {
             nSequence = std::numeric_limits<uint32_t>::max() - 1;
         } else {
@@ -372,7 +373,7 @@ UniValue createrawtransaction(const JSONRPCRequest& request)
             int64_t seqNr64 = sequenceObj.get_int64();
             if (seqNr64 < 0 || seqNr64 > std::numeric_limits<uint32_t>::max()) {
                 throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, sequence number is out of range");
-            } else if (seqNr64 <= std::numeric_limits<uint32_t>::max() - 2 && request.params.size() > 3 && request.params[3].isFalse()) {
+            } else if (seqNr64 <= MAX_BIP125_RBF_SEQUENCE && request.params.size() > 3 && request.params[3].isFalse()) {
                 throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter combination: Sequence number contradicts optintorbf option");
             } else {
                 nSequence = (uint32_t)seqNr64;

src/wallet/wallet.cpp

@@ -2685,9 +2685,10 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
                 // and in the spirit of "smallest possible change from prior
                 // behavior."
                 bool rbf = coinControl ? coinControl->signalRbf : fWalletRbf;
+                const uint32_t nSequence = rbf ? MAX_BIP125_RBF_SEQUENCE : (std::numeric_limits<unsigned int>::max() - 1);
                 for (const auto& coin : setCoins)
                     txNew.vin.push_back(CTxIn(coin.outpoint,CScript(),
-                                              std::numeric_limits<unsigned int>::max() - (rbf ? 2 : 1)));
+                                              nSequence));
 
                 // Fill in dummy signatures for fee calculation.
                 if (!DummySignTx(txNew, setCoins)) {