text: // Copyright (c) 2011-2020 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  // Unit tests for denial-of-service detection/prevention code
  
  #include <banman.h>
  #include <chainparams.h>
  #include <net.h>
  #include <net_processing.h>
  #include <script/sign.h>
  #include <script/signingprovider.h>
  #include <script/standard.h>
  #include <serialize.h>
  #include <util/memory.h>
  #include <util/string.h>
  #include <util/system.h>
  #include <util/time.h>
  #include <validation.h>
  
  #include <test/util/setup_common.h>
  
  #include <stdint.h>
  
  #include <boost/test/unit_test.hpp>
  
  struct CConnmanTest : public CConnman {
      using CConnman::CConnman;
      void AddNode(CNode& node)
      {
          LOCK(cs_vNodes);
          vNodes.push_back(&node);
      }
      void ClearNodes()
      {
          LOCK(cs_vNodes);
          for (CNode* node : vNodes) {
              delete node;
          }
          vNodes.clear();
      }
  };
  
  // Tests these internal-to-net_processing.cpp methods:
  extern bool AddOrphanTx(const CTransactionRef& tx, NodeId peer);
  extern void EraseOrphansFor(NodeId peer);
  extern unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans);
  extern void Misbehaving(NodeId nodeid, int howmuch, const std::string& message="");
  
  struct COrphanTx {
      CTransactionRef tx;
      NodeId fromPeer;
      int64_t nTimeExpire;
  };
  extern std::map<uint256, COrphanTx> mapOrphanTransactions GUARDED_BY(g_cs_orphans);
  
  static CService ip(uint32_t i)
  {
      struct in_addr s;
      s.s_addr = i;
      return CService(CNetAddr(s), Params().GetDefaultPort());
  }
  
  static NodeId id = 0;
  
  void UpdateLastBlockAnnounceTime(NodeId node, int64_t time_in_seconds);
  
  BOOST_FIXTURE_TEST_SUITE(denialofservice_tests, TestingSetup)
  
  // Test eviction of an outbound peer whose chain never advances
  // Mock a node connection, and use mocktime to simulate a peer
  // which never sends any headers messages.  PeerLogic should
  // decide to evict that outbound peer, after the appropriate timeouts.
  // Note that we protect 4 outbound nodes from being subject to
  // this logic; this test takes advantage of that protection only
  // being applied to nodes which send headers with sufficient
  // work.
  BOOST_AUTO_TEST_CASE(outbound_slow_chain_eviction)
  {
      auto connman = MakeUnique<CConnman>(0x1337, 0x1337);
      auto peerLogic = MakeUnique<PeerLogicValidation>(connman.get(), nullptr, *m_node.scheduler, *m_node.chainman, *m_node.mempool);
  
      // Mock an outbound peer
      CAddress addr1(ip(0xa0b0c001), NODE_NONE);
      CNode dummyNode1(id++, ServiceFlags(NODE_NETWORK|NODE_WITNESS), 0, INVALID_SOCKET, addr1, 0, 0, CAddress(), "", /*fInboundIn=*/ false);
      dummyNode1.SetSendVersion(PROTOCOL_VERSION);
  
      peerLogic->InitializeNode(&dummyNode1);
      dummyNode1.nVersion = 1;
      dummyNode1.fSuccessfullyConnected = true;
  
      // This test requires that we have a chain with non-zero work.
      {
          LOCK(cs_main);
          BOOST_CHECK(::ChainActive().Tip() != nullptr);
          BOOST_CHECK(::ChainActive().Tip()->nChainWork > 0);
      }
  
      // Test starts here
      {
          LOCK2(cs_main, dummyNode1.cs_sendProcessing);
          BOOST_CHECK(peerLogic->SendMessages(&dummyNode1)); // should result in getheaders
      }
      {
          LOCK2(cs_main, dummyNode1.cs_vSend);
          BOOST_CHECK(dummyNode1.vSendMsg.size() > 0);
          dummyNode1.vSendMsg.clear();
      }
  
      int64_t nStartTime = GetTime();
      // Wait 21 minutes
      SetMockTime(nStartTime+21*60);
      {
          LOCK2(cs_main, dummyNode1.cs_sendProcessing);
          BOOST_CHECK(peerLogic->SendMessages(&dummyNode1)); // should result in getheaders
      }
      {
          LOCK2(cs_main, dummyNode1.cs_vSend);
          BOOST_CHECK(dummyNode1.vSendMsg.size() > 0);
      }
      // Wait 3 more minutes
      SetMockTime(nStartTime+24*60);
      {
          LOCK2(cs_main, dummyNode1.cs_sendProcessing);
          BOOST_CHECK(peerLogic->SendMessages(&dummyNode1)); // should result in disconnect
      }
      BOOST_CHECK(dummyNode1.fDisconnect == true);
      SetMockTime(0);
  
      bool dummy;
      peerLogic->FinalizeNode(dummyNode1.GetId(), dummy);
  }
  
  static void AddRandomOutboundPeer(std::vector<CNode *> &vNodes, PeerLogicValidation &peerLogic, CConnmanTest* connman)
  {
      CAddress addr(ip(g_insecure_rand_ctx.randbits(32)), NODE_NONE);
      vNodes.emplace_back(new CNode(id++, ServiceFlags(NODE_NETWORK|NODE_WITNESS), 0, INVALID_SOCKET, addr, 0, 0, CAddress(), "", /*fInboundIn=*/ false));
      CNode &node = *vNodes.back();
      node.SetSendVersion(PROTOCOL_VERSION);
  
      peerLogic.InitializeNode(&node);
      node.nVersion = 1;
      node.fSuccessfullyConnected = true;
  
      connman->AddNode(node);
  }
  
  BOOST_AUTO_TEST_CASE(stale_tip_peer_management)
  {
      auto connman = MakeUnique<CConnmanTest>(0x1337, 0x1337);
      auto peerLogic = MakeUnique<PeerLogicValidation>(connman.get(), nullptr, *m_node.scheduler, *m_node.chainman, *m_node.mempool);
  
      const Consensus::Params& consensusParams = Params().GetConsensus();
      constexpr int max_outbound_full_relay = MAX_OUTBOUND_FULL_RELAY_CONNECTIONS;
      CConnman::Options options;
      options.nMaxConnections = DEFAULT_MAX_PEER_CONNECTIONS;
      options.m_max_outbound_full_relay = max_outbound_full_relay;
      options.nMaxFeeler = MAX_FEELER_CONNECTIONS;
  
      connman->Init(options);
      std::vector<CNode *> vNodes;
  
      // Mock some outbound peers
      for (int i=0; i<max_outbound_full_relay; ++i) {
          AddRandomOutboundPeer(vNodes, *peerLogic, connman.get());
      }
  
      peerLogic->CheckForStaleTipAndEvictPeers(consensusParams);
  
      // No nodes should be marked for disconnection while we have no extra peers
      for (const CNode *node : vNodes) {
          BOOST_CHECK(node->fDisconnect == false);
      }
  
      SetMockTime(GetTime() + 3*consensusParams.nPowTargetSpacing + 1);
  
      // Now tip should definitely be stale, and we should look for an extra
      // outbound peer
      peerLogic->CheckForStaleTipAndEvictPeers(consensusParams);
      BOOST_CHECK(connman->GetTryNewOutboundPeer());
  
      // Still no peers should be marked for disconnection
      for (const CNode *node : vNodes) {
          BOOST_CHECK(node->fDisconnect == false);
      }
  
      // If we add one more peer, something should get marked for eviction
      // on the next check (since we're mocking the time to be in the future, the
      // required time connected check should be satisfied).
      AddRandomOutboundPeer(vNodes, *peerLogic, connman.get());
  
      peerLogic->CheckForStaleTipAndEvictPeers(consensusParams);
      for (int i=0; i<max_outbound_full_relay; ++i) {
          BOOST_CHECK(vNodes[i]->fDisconnect == false);
      }
      // Last added node should get marked for eviction
      BOOST_CHECK(vNodes.back()->fDisconnect == true);
  
      vNodes.back()->fDisconnect = false;
  
      // Update the last announced block time for the last
      // peer, and check that the next newest node gets evicted.
      UpdateLastBlockAnnounceTime(vNodes.back()->GetId(), GetTime());
  
      peerLogic->CheckForStaleTipAndEvictPeers(consensusParams);
      for (int i=0; i<max_outbound_full_relay-1; ++i) {
          BOOST_CHECK(vNodes[i]->fDisconnect == false);
      }
      BOOST_CHECK(vNodes[max_outbound_full_relay-1]->fDisconnect == true);
      BOOST_CHECK(vNodes.back()->fDisconnect == false);
  
      bool dummy;
      for (const CNode *node : vNodes) {
          peerLogic->FinalizeNode(node->GetId(), dummy);
      }
  
      connman->ClearNodes();
  }
  
  BOOST_AUTO_TEST_CASE(peer_discouragement)
  {
      auto banman = MakeUnique<BanMan>(GetDataDir() / "banlist.dat", nullptr, DEFAULT_MISBEHAVING_BANTIME);
      auto connman = MakeUnique<CConnman>(0x1337, 0x1337);
      auto peerLogic = MakeUnique<PeerLogicValidation>(connman.get(), banman.get(), *m_node.scheduler, *m_node.chainman, *m_node.mempool);
  
      banman->ClearBanned();
      CAddress addr1(ip(0xa0b0c001), NODE_NONE);
      CNode dummyNode1(id++, NODE_NETWORK, 0, INVALID_SOCKET, addr1, 0, 0, CAddress(), "", true);
      dummyNode1.SetSendVersion(PROTOCOL_VERSION);
      peerLogic->InitializeNode(&dummyNode1);
      dummyNode1.nVersion = 1;
      dummyNode1.fSuccessfullyConnected = true;
      {
          LOCK(cs_main);
          Misbehaving(dummyNode1.GetId(), DISCOURAGEMENT_THRESHOLD); // Should be discouraged
      }
      {
          LOCK2(cs_main, dummyNode1.cs_sendProcessing);
          BOOST_CHECK(peerLogic->SendMessages(&dummyNode1));
      }
      BOOST_CHECK(banman->IsDiscouraged(addr1));
      BOOST_CHECK(!banman->IsDiscouraged(ip(0xa0b0c001|0x0000ff00))); // Different IP, not discouraged
  
      CAddress addr2(ip(0xa0b0c002), NODE_NONE);
      CNode dummyNode2(id++, NODE_NETWORK, 0, INVALID_SOCKET, addr2, 1, 1, CAddress(), "", true);
      dummyNode2.SetSendVersion(PROTOCOL_VERSION);
      peerLogic->InitializeNode(&dummyNode2);
      dummyNode2.nVersion = 1;
      dummyNode2.fSuccessfullyConnected = true;
      {
          LOCK(cs_main);
          Misbehaving(dummyNode2.GetId(), DISCOURAGEMENT_THRESHOLD - 1);
      }
      {
          LOCK2(cs_main, dummyNode2.cs_sendProcessing);
          BOOST_CHECK(peerLogic->SendMessages(&dummyNode2));
      }
      BOOST_CHECK(!banman->IsDiscouraged(addr2)); // 2 not discouraged yet...
      BOOST_CHECK(banman->IsDiscouraged(addr1));  // ... but 1 still should be
      {
          LOCK(cs_main);
          Misbehaving(dummyNode2.GetId(), 1); // 2 reaches discouragement threshold
      }
      {
          LOCK2(cs_main, dummyNode2.cs_sendProcessing);
          BOOST_CHECK(peerLogic->SendMessages(&dummyNode2));
      }
      BOOST_CHECK(banman->IsDiscouraged(addr1));  // Expect both 1 and 2
      BOOST_CHECK(banman->IsDiscouraged(addr2));  // to be discouraged now
  
      bool dummy;
      peerLogic->FinalizeNode(dummyNode1.GetId(), dummy);
      peerLogic->FinalizeNode(dummyNode2.GetId(), dummy);
  }
  
  BOOST_AUTO_TEST_CASE(DoS_bantime)
  {
      auto banman = MakeUnique<BanMan>(GetDataDir() / "banlist.dat", nullptr, DEFAULT_MISBEHAVING_BANTIME);
      auto connman = MakeUnique<CConnman>(0x1337, 0x1337);
      auto peerLogic = MakeUnique<PeerLogicValidation>(connman.get(), banman.get(), *m_node.scheduler, *m_node.chainman, *m_node.mempool);
  
      banman->ClearBanned();
      int64_t nStartTime = GetTime();
      SetMockTime(nStartTime); // Overrides future calls to GetTime()
  
      CAddress addr(ip(0xa0b0c001), NODE_NONE);
      CNode dummyNode(id++, NODE_NETWORK, 0, INVALID_SOCKET, addr, 4, 4, CAddress(), "", true);
      dummyNode.SetSendVersion(PROTOCOL_VERSION);
      peerLogic->InitializeNode(&dummyNode);
      dummyNode.nVersion = 1;
      dummyNode.fSuccessfullyConnected = true;
  
      {
          LOCK(cs_main);
          Misbehaving(dummyNode.GetId(), DISCOURAGEMENT_THRESHOLD);
      }
      {
          LOCK2(cs_main, dummyNode.cs_sendProcessing);
          BOOST_CHECK(peerLogic->SendMessages(&dummyNode));
      }
      BOOST_CHECK(banman->IsDiscouraged(addr));
  
      bool dummy;
      peerLogic->FinalizeNode(dummyNode.GetId(), dummy);
  }
  
  static CTransactionRef RandomOrphan()
  {
      std::map<uint256, COrphanTx>::iterator it;
      LOCK2(cs_main, g_cs_orphans);
      it = mapOrphanTransactions.lower_bound(InsecureRand256());
      if (it == mapOrphanTransactions.end())
          it = mapOrphanTransactions.begin();
      return it->second.tx;
  }
  
  BOOST_AUTO_TEST_CASE(DoS_mapOrphans)
  {
      CKey key;
      key.MakeNewKey(true);
      FillableSigningProvider keystore;
      BOOST_CHECK(keystore.AddKey(key));
  
      // 50 orphan transactions:
      for (int i = 0; i < 50; i++)
      {
          CMutableTransaction tx;
          tx.vin.resize(1);
          tx.vin[0].prevout.n = 0;
          tx.vin[0].prevout.hash = InsecureRand256();
          tx.vin[0].scriptSig << OP_1;
          tx.vout.resize(1);
          tx.vout[0].nValue = 1*CENT;
          tx.vout[0].scriptPubKey = GetScriptForDestination(PKHash(key.GetPubKey()));
  
          AddOrphanTx(MakeTransactionRef(tx), i);
      }
  
      // ... and 50 that depend on other orphans:
      for (int i = 0; i < 50; i++)
      {
          CTransactionRef txPrev = RandomOrphan();
  
          CMutableTransaction tx;
          tx.vin.resize(1);
          tx.vin[0].prevout.n = 0;
          tx.vin[0].prevout.hash = txPrev->GetHash();
          tx.vout.resize(1);
          tx.vout[0].nValue = 1*CENT;
          tx.vout[0].scriptPubKey = GetScriptForDestination(PKHash(key.GetPubKey()));
          BOOST_CHECK(SignSignature(keystore, *txPrev, tx, 0, SIGHASH_ALL));
  
          AddOrphanTx(MakeTransactionRef(tx), i);
      }
  
      // This really-big orphan should be ignored:
      for (int i = 0; i < 10; i++)
      {
          CTransactionRef txPrev = RandomOrphan();
  
          CMutableTransaction tx;
          tx.vout.resize(1);
          tx.vout[0].nValue = 1*CENT;
          tx.vout[0].scriptPubKey = GetScriptForDestination(PKHash(key.GetPubKey()));
          tx.vin.resize(2777);
          for (unsigned int j = 0; j < tx.vin.size(); j++)
          {
              tx.vin[j].prevout.n = j;
              tx.vin[j].prevout.hash = txPrev->GetHash();
          }
          BOOST_CHECK(SignSignature(keystore, *txPrev, tx, 0, SIGHASH_ALL));
          // Re-use same signature for other inputs
          // (they don't have to be valid for this test)
          for (unsigned int j = 1; j < tx.vin.size(); j++)
              tx.vin[j].scriptSig = tx.vin[0].scriptSig;
  
          BOOST_CHECK(!AddOrphanTx(MakeTransactionRef(tx), i));
      }
  
      LOCK2(cs_main, g_cs_orphans);
      // Test EraseOrphansFor:
      for (NodeId i = 0; i < 3; i++)
      {
          size_t sizeBefore = mapOrphanTransactions.size();
          EraseOrphansFor(i);
          BOOST_CHECK(mapOrphanTransactions.size() < sizeBefore);
      }
  
      // Test LimitOrphanTxSize() function:
      LimitOrphanTxSize(40);
      BOOST_CHECK(mapOrphanTransactions.size() <= 40);
      LimitOrphanTxSize(10);
      BOOST_CHECK(mapOrphanTransactions.size() <= 10);
      LimitOrphanTxSize(0);
      BOOST_CHECK(mapOrphanTransactions.empty());
  }
  
  BOOST_AUTO_TEST_SUITE_END()
  