Package Relay Draft 2 (Orphanage Eviction Approach)

src/Makefile.am

@@ -220,6 +220,7 @@ BITCOIN_CORE_H = \
   node/minisketchwrapper.h \
   node/psbt.h \
   node/transaction.h \
+  node/txpackagetracker.h \
   node/txreconciliation.h \
   node/utxo_snapshot.h \
   node/validation_cache_args.h \
@@ -412,6 +413,7 @@ libbitcoin_node_a_SOURCES = \
   node/minisketchwrapper.cpp \
   node/psbt.cpp \
   node/transaction.cpp \
+  node/txpackagetracker.cpp \
   node/txreconciliation.cpp \
   node/utxo_snapshot.cpp \
   node/validation_cache_args.cpp \

src/Makefile.test.include

@@ -151,6 +151,7 @@ BITCOIN_TESTS =\
   test/translation_tests.cpp \
   test/txindex_tests.cpp \
   test/txpackage_tests.cpp \
+  test/txpackagetracker_tests.cpp \
   test/txreconciliation_tests.cpp \
   test/txrequest_tests.cpp \
   test/txvalidation_tests.cpp \
@@ -237,6 +238,7 @@ test_fuzz_fuzz_SOURCES = \
  $(FUZZ_WALLET_SRC) \
  test/fuzz/addition_overflow.cpp \
  test/fuzz/addrman.cpp \
+ test/fuzz/ancestorpackage.cpp \
  test/fuzz/asmap.cpp \
  test/fuzz/asmap_direct.cpp \
  test/fuzz/autofile.cpp \

src/consensus/validation.h

@@ -54,6 +54,7 @@ enum class TxValidationResult {
     TX_CONFLICT,
     TX_MEMPOOL_POLICY,        //!< violated mempool's fee/size/descendant/RBF/etc limits
     TX_NO_MEMPOOL,            //!< this node does not have a mempool so can't validate the transaction
+    TX_LOW_FEE,               //!< fee was insufficient to meet some policy (minimum/RBF/etc)
 };
 
 /** A "reason" why a block was invalid, suitable for determining whether the

src/init.cpp

@@ -47,6 +47,7 @@
 #include <node/mempool_args.h>
 #include <node/mempool_persist_args.h>
 #include <node/miner.h>
+#include <node/txpackagetracker.h>
 #include <node/txreconciliation.h>
 #include <node/validation_cache_args.h>
 #include <policy/feerate.h>
@@ -489,6 +490,7 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-i2psam=<ip:port>", "I2P SAM proxy to reach I2P peers and accept I2P connections (default: none)", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-i2pacceptincoming", strprintf("Whether to accept inbound I2P connections (default: %i). Ignored if -i2psam is not set. Listening for inbound I2P connections is done through the SAM proxy, not by binding to a local address and port.", DEFAULT_I2P_ACCEPT_INCOMING), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-onlynet=<net>", "Make automatic outbound connections only to network <net> (" + Join(GetNetworkNames(), ", ") + "). Inbound and manual connections are not affected by this option. It can be specified multiple times to allow multiple networks.", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    argsman.AddArg("-packagerelay", strprintf("[EXPERIMENTAL] Support relaying transaction packages (default: %u)", node::DEFAULT_ENABLE_PACKAGE_RELAY), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-peerbloomfilters", strprintf("Support filtering of blocks and transaction with bloom filters (default: %u)", DEFAULT_PEERBLOOMFILTERS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-peerblockfilters", strprintf("Serve compact block filters to peers per BIP 157 (default: %u)", DEFAULT_PEERBLOCKFILTERS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-txreconciliation", strprintf("Enable transaction reconciliations per BIP 330 (default: %d)", DEFAULT_TXRECONCILIATION_ENABLE), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CONNECTION);
@@ -1556,10 +1558,11 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     }
 
     ChainstateManager& chainman = *Assert(node.chainman);
+    const bool enable_package_relay{gArgs.GetBoolArg("-packagerelay", node::DEFAULT_ENABLE_PACKAGE_RELAY)};
 
     assert(!node.peerman);
     node.peerman = PeerManager::make(*node.connman, *node.addrman, node.banman.get(),
-                                     chainman, *node.mempool, ignores_incoming_txs);
+                                     chainman, *node.mempool, ignores_incoming_txs, enable_package_relay);
     RegisterValidationInterface(node.peerman.get());
 
     // ********************************************************* Step 8: start indexers

src/kernel/mempool_persist.cpp

@@ -63,6 +63,7 @@ bool LoadMempool(CTxMemPool& pool, const fs::path& load_path, Chainstate& active
         }
         uint64_t num;
         file >> num;
+        LOCK2(cs_main, pool.cs);
         while (num) {
             --num;
             CTransactionRef tx;
@@ -77,8 +78,12 @@ bool LoadMempool(CTxMemPool& pool, const fs::path& load_path, Chainstate& active
                 pool.PrioritiseTransaction(tx->GetHash(), amountdelta);
             }
             if (nTime > TicksSinceEpoch<std::chrono::seconds>(now - pool.m_expiry)) {
-                LOCK(cs_main);
-                const auto& accepted = AcceptToMemoryPool(active_chainstate, tx, nTime, /*bypass_limits=*/false, /*test_accept=*/false);
+                // Use bypass_limits=true to skip feerate checks, and call TrimToSize() at the very
+                // end. This means the mempool may temporarily exceed its maximum capacity. However,
+                // this means fee-bumped transactions are persisted, and the resulting mempool
+                // minimum feerate is not dependent on the order in which transactions are loaded
+                // from disk.
+                const auto& accepted = AcceptToMemoryPool(active_chainstate, tx, nTime, /*bypass_limits=*/true, /*test_accept=*/false);
                 if (accepted.m_result_type == MempoolAcceptResult::ResultType::VALID) {
                     ++count;
                 } else {
@@ -104,6 +109,13 @@ bool LoadMempool(CTxMemPool& pool, const fs::path& load_path, Chainstate& active
         for (const auto& i : mapDeltas) {
             pool.PrioritiseTransaction(i.first, i.second);
         }
+        const auto size_before_trim{pool.size()};
+        // Ensure the maximum memory limits are ultimately enforced and any transactions below
+        // minimum feerates are evicted, since bypass_limits was set to true during ATMP calls.
+        pool.TrimToSize(pool.m_max_size_bytes);
+        const auto num_evicted{size_before_trim - pool.size()};
+        count -= num_evicted;
+        failed += num_evicted;
 
         std::set<uint256> unbroadcast_txids;
         file >> unbroadcast_txids;

src/logging.cpp

@@ -182,6 +182,7 @@ const CLogCategoryDesc LogCategories[] =
     {BCLog::BLOCKSTORE, "blockstorage"},
     {BCLog::TXRECONCILIATION, "txreconciliation"},
     {BCLog::SCAN, "scan"},
+    {BCLog::TXPACKAGES, "txpackages"},
     {BCLog::ALL, "1"},
     {BCLog::ALL, "all"},
 };
@@ -286,6 +287,8 @@ std::string LogCategoryToStr(BCLog::LogFlags category)
         return "txreconciliation";
     case BCLog::LogFlags::SCAN:
         return "scan";
+    case BCLog::LogFlags::TXPACKAGES:
+        return "txpackages";
     case BCLog::LogFlags::ALL:
         return "all";
     }

src/logging.h

@@ -68,6 +68,7 @@ namespace BCLog {
         BLOCKSTORE  = (1 << 26),
         TXRECONCILIATION = (1 << 27),
         SCAN        = (1 << 28),
+        TXPACKAGES  = (1 << 29),
         ALL         = ~(uint32_t)0,
     };
     enum class Level {