From acaf0600e70ac712d81c021cd9f0f6e897e26157 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Tue, 18 Oct 2016 06:39:00 -0700
Subject: [PATCH] mempool: do not accept replace by fee.

---
 lib/mempool/mempool.js  |  6 ++++++
 lib/primitives/input.js |  9 +++++++++
 lib/primitives/tx.js    | 25 +++++++++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/lib/mempool/mempool.js b/lib/mempool/mempool.js
index 6757c7a9..25a48abb 100644
--- a/lib/mempool/mempool.js
+++ b/lib/mempool/mempool.js
@@ -644,6 +644,12 @@ Mempool.prototype._addTX = co(function* _addTX(tx) {
         ret.reason,
         ret.score);
     }
+    if (tx.isRBF()) {
+      throw new VerifyError(tx,
+        'nonstandard',
+        'replace-by-fee',
+        0);
+    }
   }
 
   result = yield this.chain.checkFinal(this.chain.tip, tx, lockFlags);
diff --git a/lib/primitives/input.js b/lib/primitives/input.js
index 1f8b3c9a..68b8cd1d 100644
--- a/lib/primitives/input.js
+++ b/lib/primitives/input.js
@@ -221,6 +221,15 @@ Input.prototype.isFinal = function isFinal() {
   return this.sequence === 0xffffffff;
 };
 
+/**
+ * Test to see if nSequence is less than 0xfffffffe.
+ * @returns {Boolean}
+ */
+
+Input.prototype.isRBF = function isRBF() {
+  return this.sequence < 0xfffffffe;
+};
+
 /**
  * Test to see if outpoint is null.
  * @returns {Boolean}
diff --git a/lib/primitives/tx.js b/lib/primitives/tx.js
index 5e9cb075..06ed05d4 100644
--- a/lib/primitives/tx.js
+++ b/lib/primitives/tx.js
@@ -782,6 +782,31 @@ TX.prototype.isCoinbase = function isCoinbase() {
   return this.inputs.length === 1 && this.inputs[0].prevout.isNull();
 };
 
+/**
+ * Test whether the transaction is a replacement.
+ * @returns {Boolean}
+ */
+
+TX.prototype.isRBF = function isRBF() {
+  var i, input;
+
+  for (i = 0; i < this.inputs.length; i++) {
+    input = this.inputs[i];
+
+    if (!input.isRBF())
+      continue;
+
+    if (this.version === 2) {
+      if (!(input.sequence & constants.sequence.DISABLE_FLAG))
+        continue;
+    }
+
+    return true;
+  }
+
+  return false;
+};
+
 /**
  * Calculate the fee for the transaction.
  * @returns {Amount} fee (zero if not all coins are available).