1 files changed, 38 insertions, 0 deletions
diff --git a/src/txorphanage.cpp b/src/txorphanage.cpp
index 6baea9f69e..1527bdf5ea 100644
--- a/src/txorphanage.cpp
+++ b/src/txorphanage.cpp
@@ -10,6 +10,8 @@
 
 #include <cassert>
 
+/** Expiration time for orphan transactions in seconds */
+static constexpr int64_t ORPHAN_TX_EXPIRE_TIME = 20 * 60;
 /** Minimum time between orphan transactions expire time checks in seconds */
 static constexpr int64_t ORPHAN_TX_EXPIRE_INTERVAL = 5 * 60;
 
@@ -22,6 +24,42 @@ std::map<uint256, std::map<uint256, COrphanTx>::iterator> g_orphans_by_wtxid GUA
 
     std::vector<std::map<uint256, COrphanTx>::iterator> g_orphan_list GUARDED_BY(g_cs_orphans);
 
+bool OrphanageAddTx(const CTransactionRef& tx, NodeId peer)
+{
+    AssertLockHeld(g_cs_orphans);
+
+    const uint256& hash = tx->GetHash();
+    if (mapOrphanTransactions.count(hash))
+        return false;
+
+    // Ignore big transactions, to avoid a
+    // send-big-orphans memory exhaustion attack. If a peer has a legitimate
+    // large transaction with a missing parent then we assume
+    // it will rebroadcast it later, after the parent transaction(s)
+    // have been mined or received.
+    // 100 orphans, each of which is at most 100,000 bytes big is
+    // at most 10 megabytes of orphans and somewhat more byprev index (in the worst case):
+    unsigned int sz = GetTransactionWeight(*tx);
+    if (sz > MAX_STANDARD_TX_WEIGHT)
+    {
+        LogPrint(BCLog::MEMPOOL, "ignoring large orphan tx (size: %u, hash: %s)\n", sz, hash.ToString());
+        return false;
+    }
+
+    auto ret = mapOrphanTransactions.emplace(hash, COrphanTx{tx, peer, GetTime() + ORPHAN_TX_EXPIRE_TIME, g_orphan_list.size()});
+    assert(ret.second);
+    g_orphan_list.push_back(ret.first);
+    // Allow for lookups in the orphan pool by wtxid, as well as txid
+    g_orphans_by_wtxid.emplace(tx->GetWitnessHash(), ret.first);
+    for (const CTxIn& txin : tx->vin) {
+        mapOrphanTransactionsByPrev[txin.prevout].insert(ret.first);
+    }
+
+    LogPrint(BCLog::MEMPOOL, "stored orphan tx %s (mapsz %u outsz %u)\n", hash.ToString(),
+             mapOrphanTransactions.size(), mapOrphanTransactionsByPrev.size());
+    return true;
+}
+
 int EraseOrphanTx(const uint256& txid)
 {
     std::map<uint256, COrphanTx>::iterator it = mapOrphanTransactions.find(txid);