oxen-core/src/cryptonote_core/service_node_list.cpp

// Copyright (c)      2018, The Loki Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
//    conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
//    of conditions and the following disclaimer in the documentation and/or other
//    materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
//    used to endorse or promote products derived from this software without specific
//    prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <functional>
#include <random>


#include "ringct/rctSigs.h"
#include "wallet/wallet2.h"
#include "cryptonote_tx_utils.h"
#include "cryptonote_basic/tx_extra.h"
#include "common/int-util.h"
#include "common/scoped_message_writer.h"
#include "common/i18n.h"
#include "quorum_cop.h"
#include "common/exp2.h"

#include "service_node_list.h"

#undef LOKI_DEFAULT_LOG_CATEGORY
#define LOKI_DEFAULT_LOG_CATEGORY "service_nodes"

namespace service_nodes
{
  uint64_t service_node_info::get_min_contribution() const
  {
    uint64_t result = get_min_node_contribution(staking_requirement, total_reserved);
    return result;
  }

  service_node_list::service_node_list(cryptonote::Blockchain& blockchain)
    : m_blockchain(blockchain), m_hooks_registered(false), m_height(0), m_db(nullptr), m_service_node_pubkey(nullptr)
  {
  }

  void service_node_list::register_hooks(service_nodes::quorum_cop &quorum_cop)
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    if (!m_hooks_registered)
    {
      m_hooks_registered = true;
      m_blockchain.hook_block_added(*this);
      m_blockchain.hook_blockchain_detached(*this);
      m_blockchain.hook_init(*this);
      m_blockchain.hook_validate_miner_tx(*this);

      // NOTE: There is an implicit dependency on service node lists hooks
      m_blockchain.hook_init(quorum_cop);
      m_blockchain.hook_block_added(quorum_cop);
      m_blockchain.hook_blockchain_detached(quorum_cop);
    }
  }

  void service_node_list::init()
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    if (m_blockchain.get_current_hard_fork_version() < 9)
    {
      clear(true);
      return;
    }

    uint64_t current_height = m_blockchain.get_current_blockchain_height();
    bool loaded = load();

    if (loaded && m_height == current_height) return;

    if (!loaded || m_height > current_height) clear(true);

    LOG_PRINT_L0("Recalculating service nodes list, scanning blockchain from height " << m_height);
    LOG_PRINT_L0("This may take some time...");

    std::vector<std::pair<cryptonote::blobdata, cryptonote::block>> blocks;
    while (m_height < current_height)
    {
      blocks.clear();
      if (!m_blockchain.get_blocks(m_height, 1000, blocks))
      {
        LOG_ERROR("Unable to initialize service nodes list");
        return;
      }

      std::vector<cryptonote::transaction> txs;
      std::vector<crypto::hash> missed_txs;
      for (const auto& block_pair : blocks)
      {
        txs.clear();
        missed_txs.clear();

        const cryptonote::block& block = block_pair.second;
        std::vector<cryptonote::transaction> txs;
        std::vector<crypto::hash> missed_txs;
        if (!m_blockchain.get_transactions(block.tx_hashes, txs, missed_txs))
        {
          LOG_ERROR("Unable to get transactions for block " << block.hash);
          return;
        }

        block_added_generic(block, txs);
      }
    }
  }

  std::vector<crypto::public_key> service_node_list::get_service_nodes_pubkeys() const
  {
    std::vector<crypto::public_key> result;
    for (const auto& iter : m_service_nodes_infos)
      if (iter.second.is_fully_funded())
        result.push_back(iter.first);

    std::sort(result.begin(), result.end(),
      [](const crypto::public_key &a, const crypto::public_key &b) {
        return memcmp(reinterpret_cast<const void*>(&a), reinterpret_cast<const void*>(&b), sizeof(a)) < 0;
      });
    return result;
  }

  const std::shared_ptr<const quorum_state> service_node_list::get_quorum_state(uint64_t height) const
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    const auto &it = m_quorum_states.find(height);
    if (it == m_quorum_states.end())
    {
      // TODO(loki): Not being able to find the quorum is going to be a fatal error.
    }
    else
    {
      return it->second;
    }

    return std::make_shared<quorum_state>();
  }

  std::vector<service_node_pubkey_info> service_node_list::get_service_node_list_state(const std::vector<crypto::public_key> &service_node_pubkeys) const
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    std::vector<service_node_pubkey_info> result;

    if (service_node_pubkeys.empty())
    {
      result.reserve(m_service_nodes_infos.size());

      for (const auto &it : m_service_nodes_infos)
      {
        service_node_pubkey_info entry = {};
        entry.pubkey                   = it.first;
        entry.info                     = it.second;
        result.push_back(entry);
      }
    }
    else
    {
      result.reserve(service_node_pubkeys.size());
      for (const auto &it : service_node_pubkeys)
      {
        const auto &find_it = m_service_nodes_infos.find(it);
        if (find_it == m_service_nodes_infos.end())
          continue;

        service_node_pubkey_info entry = {};
        entry.pubkey                   = (*find_it).first;
        entry.info                     = (*find_it).second;
        result.push_back(entry);
      }
    }

    return result;
  }

  void service_node_list::set_db_pointer(cryptonote::BlockchainDB* db)
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    m_db = db;
  }

  void service_node_list::set_my_service_node_keys(crypto::public_key const *pub_key)
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    m_service_node_pubkey = pub_key;
  }

  bool service_node_list::is_service_node(const crypto::public_key& pubkey) const
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    return m_service_nodes_infos.find(pubkey) != m_service_nodes_infos.end();
  }

  bool service_node_list::contribution_tx_output_has_correct_unlock_time(const cryptonote::transaction& tx, size_t i, uint64_t block_height) const
  {
    uint64_t unlock_time = tx.unlock_time;

    if (tx.version >= cryptonote::transaction::version_3_per_output_unlock_times)
      unlock_time = tx.output_unlock_times[i];

    return unlock_time < CRYPTONOTE_MAX_BLOCK_NUMBER && unlock_time >= block_height + get_staking_requirement_lock_blocks(m_blockchain.nettype());
  }

  bool reg_tx_extract_fields(const cryptonote::transaction& tx, std::vector<cryptonote::account_public_address>& addresses, uint64_t& portions_for_operator, std::vector<uint64_t>& portions, uint64_t& expiration_timestamp, crypto::public_key& service_node_key, crypto::signature& signature, crypto::public_key& tx_pub_key)
  {
    cryptonote::tx_extra_service_node_register registration;
    if (!get_service_node_register_from_tx_extra(tx.extra, registration))
      return false;
    if (!cryptonote::get_service_node_pubkey_from_tx_extra(tx.extra, service_node_key))
      return false;

    addresses.clear();
    addresses.reserve(registration.m_public_spend_keys.size());
    for (size_t i = 0; i < registration.m_public_spend_keys.size(); i++)
      addresses.push_back(cryptonote::account_public_address{ registration.m_public_spend_keys[i], registration.m_public_view_keys[i] });

    portions_for_operator = registration.m_portions_for_operator;
    portions = registration.m_portions;
    expiration_timestamp = registration.m_expiration_timestamp;
    signature = registration.m_service_node_signature;
    tx_pub_key = cryptonote::get_tx_pub_key_from_extra(tx.extra);

    return true;
  }

  uint64_t get_reg_tx_staking_output_contribution(const cryptonote::transaction& tx, int i, crypto::key_derivation derivation, hw::device& hwdev)
  {
    if (tx.vout[i].target.type() != typeid(cryptonote::txout_to_key))
    {
      return 0;
    }

    rct::key mask;
    uint64_t money_transferred = 0;

    crypto::secret_key scalar1;
    hwdev.derivation_to_scalar(derivation, i, scalar1);
    try
    {
      switch (tx.rct_signatures.type)
      {
      case rct::RCTTypeSimple:
      case rct::RCTTypeBulletproof:
        money_transferred = rct::decodeRctSimple(tx.rct_signatures, rct::sk2rct(scalar1), i, mask, hwdev);
        break;
      case rct::RCTTypeFull:
        money_transferred = rct::decodeRct(tx.rct_signatures, rct::sk2rct(scalar1), i, mask, hwdev);
        break;
      default:
        LOG_PRINT_L0("Unsupported rct type: " << tx.rct_signatures.type);
        return 0;
      }
    }
    catch (const std::exception &e)
    {
      LOG_PRINT_L0("Failed to decode input " << i);
      return 0;
    }

    return money_transferred;
  }

  void service_node_list::process_deregistration_tx(const cryptonote::transaction& tx, uint64_t block_height)
  {
    if (!tx.is_deregister_tx())
      return;

    cryptonote::tx_extra_service_node_deregister deregister;
    if (!cryptonote::get_service_node_deregister_from_tx_extra(tx.extra, deregister))
    {
      LOG_ERROR("Transaction deregister did not have deregister data in tx extra, possibly corrupt tx in blockchain");
      return;
    }

    const auto state = get_quorum_state(deregister.block_height);

    if (!state)
    {
      // TODO(loki): Not being able to find a quorum is fatal! We want better caching abilities.
      LOG_ERROR("Quorum state for height: " << deregister.block_height << ", was not stored by the daemon");
      return;
    }

    if (deregister.service_node_index >= state->nodes_to_test.size())
    {
      LOG_ERROR("Service node index to vote off has become invalid, quorum rules have changed without a hardfork.");
      return;
    }

    const crypto::public_key& key = state->nodes_to_test[deregister.service_node_index];

    auto iter = m_service_nodes_infos.find(key);
    if (iter == m_service_nodes_infos.end())
      return;

    if (m_service_node_pubkey && *m_service_node_pubkey == key)
    {
      MGINFO_RED("Deregistration for service node (yours): " << key);
    }
    else
    {
      LOG_PRINT_L1("Deregistration for service node: " << key);
    }


    m_rollback_events.push_back(std::unique_ptr<rollback_event>(new rollback_change(block_height, key, iter->second)));
    m_service_nodes_infos.erase(iter);
  }

  bool check_service_node_portions(const std::vector<uint64_t>& portions)
  {
    uint64_t portions_left = STAKING_PORTIONS;

    for (const auto portion : portions) {
      const uint64_t min_portions = std::min(portions_left, MIN_PORTIONS);
      if (portion < min_portions || portion > portions_left) return false;
      portions_left -= portion;
    }

    return true;
  }

  bool service_node_list::is_registration_tx(const cryptonote::transaction& tx, uint64_t block_timestamp, uint64_t block_height, uint32_t index, crypto::public_key& key, service_node_info& info) const
  {
    crypto::public_key tx_pub_key, service_node_key;
    std::vector<cryptonote::account_public_address> service_node_addresses;
    std::vector<uint64_t> service_node_portions;
    uint64_t portions_for_operator;
    uint64_t expiration_timestamp;
    crypto::signature signature;

    if (!reg_tx_extract_fields(tx, service_node_addresses, portions_for_operator, service_node_portions, expiration_timestamp, service_node_key, signature, tx_pub_key))
      return false;

    if (service_node_portions.size() != service_node_addresses.size() || service_node_portions.empty())
      return false;

    // check the portions
    if (!check_service_node_portions(service_node_portions)) return false;

    if (portions_for_operator > STAKING_PORTIONS)
      return false;

    // check the signature is all good

    crypto::hash hash;
    if (!get_registration_hash(service_node_addresses, portions_for_operator, service_node_portions, expiration_timestamp, hash))
      return false;
    if (!crypto::check_key(service_node_key) || !crypto::check_signature(hash, service_node_key, signature))
      return false;
    if (expiration_timestamp < block_timestamp)
      return false;

    // check the initial contribution exists

    info.staking_requirement = get_staking_requirement(m_blockchain.nettype(), block_height);

    cryptonote::account_public_address address;
    uint64_t transferred = 0;
    if (!get_contribution(tx, block_height, address, transferred))
      return false;
    if (transferred < info.staking_requirement / MAX_NUMBER_OF_CONTRIBUTORS)
      return false;
    int is_this_a_new_address = 0;
    if (std::find(service_node_addresses.begin(), service_node_addresses.end(), address) == service_node_addresses.end())
      is_this_a_new_address = 1;
    if (service_node_addresses.size() + is_this_a_new_address > MAX_NUMBER_OF_CONTRIBUTORS)
      return false;

    // don't actually process this contribution now, do it when we fall through later.

    key = service_node_key;

    info.operator_address = service_node_addresses[0];
    info.portions_for_operator = portions_for_operator;
    info.registration_height = block_height;
    info.last_reward_block_height = block_height;
    info.last_reward_transaction_index = index;
    info.total_contributed = 0;
    info.total_reserved = 0;
    info.contributors.clear();

    for (size_t i = 0; i < service_node_addresses.size(); i++)
    {
      // Check for duplicates
      auto iter = std::find(service_node_addresses.begin(), service_node_addresses.begin() + i, service_node_addresses[i]);
      if (iter != service_node_addresses.begin() + i)
        return false;
      uint64_t hi, lo, resulthi, resultlo;
      lo = mul128(info.staking_requirement, service_node_portions[i], &hi);
      div128_64(hi, lo, STAKING_PORTIONS, &resulthi, &resultlo);
      info.contributors.push_back(service_node_info::contribution(resultlo, service_node_addresses[i]));
      info.total_reserved += resultlo;
    }

    return true;
  }

  void service_node_list::process_registration_tx(const cryptonote::transaction& tx, uint64_t block_timestamp, uint64_t block_height, uint32_t index)
  {
    crypto::public_key key;
    service_node_info info;
    if (!is_registration_tx(tx, block_timestamp, block_height, index, key, info))
      return;

    // NOTE: A node doesn't expire until registration_height + lock blocks excess now which acts as the grace period
    // So it is possible to find the node still in our list.
    bool registered_during_grace_period = false;
    const auto iter = m_service_nodes_infos.find(key);
    if (iter != m_service_nodes_infos.end())
    {
      int hard_fork_version = m_blockchain.get_hard_fork_version(block_height);
      if (hard_fork_version >= cryptonote::Blockchain::version_10_swarms)
      {
        service_node_info const &old_info = iter->second;
        uint64_t expiry_height = old_info.registration_height + get_staking_requirement_lock_blocks(m_blockchain.nettype());
        if (block_height < expiry_height)
          return;

        // NOTE: Node preserves its position in list if it reregisters during grace period.
        registered_during_grace_period = true;
        info.last_reward_block_height = old_info.last_reward_block_height;
        info.last_reward_transaction_index = old_info.last_reward_transaction_index;
      }
      else
      {
        return;
      }
    }

    if (m_service_node_pubkey && *m_service_node_pubkey == key)
    {
      if (registered_during_grace_period)
      {
        MGINFO_GREEN("Service node re-registered (yours): " << key << " at block height: " << block_height);
      }
      else
      {
        MGINFO_GREEN("Service node registered (yours): " << key << " at block height: " << block_height);
      }
    }
    else
    {
      LOG_PRINT_L1("New service node registered: " << key << " at block height: " << block_height);
    }

    m_rollback_events.push_back(std::unique_ptr<rollback_event>(new rollback_new(block_height, key)));
    m_service_nodes_infos[key] = info;
  }

  bool service_node_list::get_contribution(const cryptonote::transaction& tx, uint64_t block_height, cryptonote::account_public_address& address, uint64_t& transferred) const
  {
    crypto::secret_key tx_key;

    if (!cryptonote::get_service_node_contributor_from_tx_extra(tx.extra, address))
      return false;
    if (!cryptonote::get_tx_secret_key_from_tx_extra(tx.extra, tx_key))
      return false;

    crypto::key_derivation derivation;
    if (!crypto::generate_key_derivation(address.m_view_public_key, tx_key, derivation))
      return false;

    hw::device& hwdev = hw::get_device("default");

    transferred = 0;
    for (size_t i = 0; i < tx.vout.size(); i++)
      if (contribution_tx_output_has_correct_unlock_time(tx, i, block_height))
        transferred += get_reg_tx_staking_output_contribution(tx, i, derivation, hwdev);

    return true;
  }

  void service_node_list::process_contribution_tx(const cryptonote::transaction& tx, uint64_t block_height, uint32_t index)
  {
    crypto::public_key pubkey;
    cryptonote::account_public_address address;
    uint64_t transferred;

    if (!cryptonote::get_service_node_pubkey_from_tx_extra(tx.extra, pubkey))
      return;
    if (!get_contribution(tx, block_height, address, transferred))
      return;

    auto iter = m_service_nodes_infos.find(pubkey);
    if (iter == m_service_nodes_infos.end())
      return;

    service_node_info& info = iter->second;

    if (info.is_fully_funded())
      return;

    auto& contributors = info.contributors;

    // Only create a new contributor if they stake at least a quarter
    // and if we don't already have the maximum
    auto contrib_iter = std::find_if(contributors.begin(), contributors.end(),
        [&address](const service_node_info::contribution& contributor) { return contributor.address == address; });
    if (contrib_iter == contributors.end())
    {
      if (contributors.size() >= MAX_NUMBER_OF_CONTRIBUTORS || transferred < info.get_min_contribution())
        return;
    }

    m_rollback_events.push_back(std::unique_ptr<rollback_event>(new rollback_change(block_height, pubkey, info)));

    if (contrib_iter == contributors.end())
    {
      contributors.push_back(service_node_info::contribution(0, address));
      contrib_iter = --contributors.end();
    }

    service_node_info::contribution& contributor = *contrib_iter;

    // In this action, we cannot
    // increase total_reserved so much that it is >= staking_requirement
    uint64_t can_increase_reserved_by = info.staking_requirement - info.total_reserved;
    uint64_t max_amount = contributor.reserved + can_increase_reserved_by;
    transferred = std::min(max_amount - contributor.amount, transferred);

    contributor.amount += transferred;
    info.total_contributed += transferred;

    if (contributor.amount > contributor.reserved)
    {
      info.total_reserved += contributor.amount - contributor.reserved;
      contributor.reserved = contributor.amount;
    }

    iter->second.last_reward_block_height = block_height;
    iter->second.last_reward_transaction_index = index;

    LOG_PRINT_L1("Contribution of " << transferred << " received for service node " << pubkey);

    return;
  }

  void service_node_list::block_added(const cryptonote::block& block, const std::vector<cryptonote::transaction>& txs)
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    block_added_generic(block, txs);
    store();
  }


  template<typename T>
  void service_node_list::block_added_generic(const cryptonote::block& block, const T& txs)
  {
    uint64_t block_height = cryptonote::get_block_height(block);
    int hard_fork_version = m_blockchain.get_hard_fork_version(block_height);

    if (hard_fork_version < 9)
      return;

    assert(m_height == block_height);
    m_height++;
    {
      const size_t ROLLBACK_EVENT_EXPIRATION_BLOCKS = 30;
      uint64_t cull_height = (block_height < ROLLBACK_EVENT_EXPIRATION_BLOCKS) ? block_height : block_height - ROLLBACK_EVENT_EXPIRATION_BLOCKS;

      while (!m_rollback_events.empty() && m_rollback_events.front()->m_block_height < cull_height)
      {
        m_rollback_events.pop_front();
      }
      m_rollback_events.push_front(std::unique_ptr<rollback_event>(new prevent_rollback(cull_height)));
    }

    for (const crypto::public_key& pubkey : get_expired_nodes(block_height))
    {
      auto i = m_service_nodes_infos.find(pubkey);
      if (i != m_service_nodes_infos.end())
      {
        if (m_service_node_pubkey && *m_service_node_pubkey == pubkey)
        {
          MGINFO_GREEN("Service node expired (yours): " << pubkey << " at block height: " << block_height);
        }
        else
        {
          LOG_PRINT_L1("Service node expired: " << pubkey << " at block height: " << block_height);
        }

        m_rollback_events.push_back(std::unique_ptr<rollback_event>(new rollback_change(block_height, pubkey, i->second)));
        m_service_nodes_infos.erase(i);
      }
      // Service nodes may expire early if they double staked by accident, so
      // expiration doesn't mean the node is in the list.
    }

    crypto::public_key winner_pubkey = cryptonote::get_service_node_winner_from_tx_extra(block.miner_tx.extra);
    if (m_service_nodes_infos.count(winner_pubkey) == 1)
    {
      m_rollback_events.push_back(
        std::unique_ptr<rollback_event>(
          new rollback_change(block_height, winner_pubkey, m_service_nodes_infos[winner_pubkey])
        )
      );
      // set the winner as though it was re-registering at transaction index=UINT32_MAX for this block
      m_service_nodes_infos[winner_pubkey].last_reward_block_height = block_height;
      m_service_nodes_infos[winner_pubkey].last_reward_transaction_index = UINT32_MAX;
    }

    uint32_t index = 0;
    for (const cryptonote::transaction& tx : txs)
    {
      crypto::public_key key;
      service_node_info info;
      cryptonote::account_public_address address;
      process_registration_tx(tx, block.timestamp, block_height, index);
      process_contribution_tx(tx, block_height, index);
      process_deregistration_tx(tx, block_height);
      index++;
    }

    const size_t QUORUM_LIFETIME         = (6 * loki::service_node_deregister::DEREGISTER_LIFETIME_BY_HEIGHT);
    // save six times the quorum lifetime, to be sure. also to help with debugging.
    const size_t cache_state_from_height = (block_height < QUORUM_LIFETIME) ? 0 : block_height - QUORUM_LIFETIME;

    store_quorum_state_from_rewards_list(block_height);

    while (!m_quorum_states.empty() && m_quorum_states.begin()->first < cache_state_from_height)
    {
      m_quorum_states.erase(m_quorum_states.begin());
    }
  }

  void service_node_list::blockchain_detached(uint64_t height)
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    while (!m_rollback_events.empty() && m_rollback_events.back()->m_block_height >= height)
    {
      if (!m_rollback_events.back()->apply(m_service_nodes_infos))
      {
        init();
        break;
      }
      m_rollback_events.pop_back();
    }

    while (!m_quorum_states.empty() && (--m_quorum_states.end())->first >= height)
    {
      m_quorum_states.erase(--m_quorum_states.end());
    }

    m_height = height;

    store();
  }

  std::vector<crypto::public_key> service_node_list::get_expired_nodes(uint64_t block_height) const
  {
    std::vector<crypto::public_key> expired_nodes;
    int hard_fork_version = m_blockchain.get_hard_fork_version(block_height);

    uint64_t lock_blocks = get_staking_requirement_lock_blocks(m_blockchain.nettype());
    if (hard_fork_version >= cryptonote::Blockchain::version_10_swarms)
      lock_blocks += STAKING_REQUIREMENT_LOCK_BLOCKS_EXCESS;

    if (block_height < lock_blocks)
      return expired_nodes;

    if (hard_fork_version >= cryptonote::Blockchain::version_10_swarms)
    {
      for (auto &it : m_service_nodes_infos)
      {
        crypto::public_key const &pubkey = it.first;
        service_node_info  const &info   = it.second;

        uint64_t node_expiry_height = info.registration_height + lock_blocks;
        if (block_height > node_expiry_height)
        {
          expired_nodes.push_back(pubkey);
        }
      }
    }
    else
    {
      const uint64_t expired_nodes_block_height = block_height - lock_blocks;
      std::vector<std::pair<cryptonote::blobdata, cryptonote::block>> blocks;
      if (!m_blockchain.get_blocks(expired_nodes_block_height, 1, blocks))
      {
          LOG_ERROR("Unable to get historical blocks");
          return expired_nodes;
      }

      const cryptonote::block& block = blocks.begin()->second;
      std::vector<cryptonote::transaction> txs;
      std::vector<crypto::hash> missed_txs;
      if (!m_blockchain.get_transactions(block.tx_hashes, txs, missed_txs))
      {
        LOG_ERROR("Unable to get transactions for block " << block.hash);
        return expired_nodes;
      }

      uint32_t index = 0;
      for (const cryptonote::transaction& tx : txs)
      {
        crypto::public_key key;
        service_node_info info;
        if (is_registration_tx(tx, block.timestamp, expired_nodes_block_height, index, key, info))
        {
          expired_nodes.push_back(key);
        }
        index++;
      }
    }

    return expired_nodes;
  }

  std::vector<std::pair<cryptonote::account_public_address, uint64_t>> service_node_list::get_winner_addresses_and_portions(const crypto::hash& prev_id) const
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    crypto::public_key key = select_winner(prev_id);
    if (key == crypto::null_pkey)
      return { std::make_pair(null_address, STAKING_PORTIONS) };

    std::vector<std::pair<cryptonote::account_public_address, uint64_t>> winners;

    const service_node_info& info = m_service_nodes_infos.at(key);

    const uint64_t remaining_portions = STAKING_PORTIONS - info.portions_for_operator;

    // Add contributors and their portions to winners.
    for (const auto& contributor : info.contributors)
    {
      uint64_t hi, lo, resulthi, resultlo;
      lo = mul128(contributor.amount, remaining_portions, &hi);
      div128_64(hi, lo, info.staking_requirement, &resulthi, &resultlo);

      if (contributor.address == info.operator_address)
        resultlo += info.portions_for_operator;

      winners.push_back(std::make_pair(contributor.address, resultlo));
    }
    return winners;
  }

  crypto::public_key service_node_list::select_winner(const crypto::hash& prev_id) const
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    auto oldest_waiting = std::pair<uint64_t, uint32_t>(std::numeric_limits<uint64_t>::max(), std::numeric_limits<uint32_t>::max());
    crypto::public_key key = crypto::null_pkey;
    for (const auto& info : m_service_nodes_infos)
      if (info.second.is_fully_funded())
      {
        auto waiting_since = std::make_pair(info.second.last_reward_block_height, info.second.last_reward_transaction_index);
        if (waiting_since < oldest_waiting)
        {
          oldest_waiting = waiting_since;
          key = info.first;
        }
      }
    return key;
  }

  /// validates the miner TX for the next block
  //
  bool service_node_list::validate_miner_tx(const crypto::hash& prev_id, const cryptonote::transaction& miner_tx, uint64_t height, int hard_fork_version, uint64_t base_reward) const
  {
    std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);
    if (hard_fork_version < 9)
      return true;

    uint64_t total_service_node_reward = cryptonote::get_service_node_reward(height, base_reward, hard_fork_version);

    crypto::public_key winner = select_winner(prev_id);

    crypto::public_key check_winner_pubkey = cryptonote::get_service_node_winner_from_tx_extra(miner_tx.extra);
    if (check_winner_pubkey != winner)
      return false;

    const std::vector<std::pair<cryptonote::account_public_address, uint64_t>> addresses_and_portions = get_winner_addresses_and_portions(prev_id);
    
    if (miner_tx.vout.size() - 1 < addresses_and_portions.size())
      return false;

    for (size_t i = 0; i < addresses_and_portions.size(); i++)
    {
      size_t vout_index = miner_tx.vout.size() - 1 /* governance */ - addresses_and_portions.size() + i;

      uint64_t reward = cryptonote::get_portion_of_reward(addresses_and_portions[i].second, total_service_node_reward);

      if (miner_tx.vout[vout_index].amount != reward)
      {
        MERROR("Service node reward amount incorrect. Should be " << cryptonote::print_money(reward) << ", is: " << cryptonote::print_money(miner_tx.vout[vout_index].amount));
        return false;
      }

      if (miner_tx.vout[vout_index].target.type() != typeid(cryptonote::txout_to_key))
      {
        MERROR("Service node output target type should be txout_to_key");
        return false;
      }

      crypto::key_derivation derivation = AUTO_VAL_INIT(derivation);;
      crypto::public_key out_eph_public_key = AUTO_VAL_INIT(out_eph_public_key);
      cryptonote::keypair gov_key = cryptonote::get_deterministic_keypair_from_height(height);

      bool r = crypto::generate_key_derivation(addresses_and_portions[i].first.m_view_public_key, gov_key.sec, derivation);
      CHECK_AND_ASSERT_MES(r, false, "while creating outs: failed to generate_key_derivation(" << addresses_and_portions[i].first.m_view_public_key << ", " << gov_key.sec << ")");
      r = crypto::derive_public_key(derivation, vout_index, addresses_and_portions[i].first.m_spend_public_key, out_eph_public_key);
      CHECK_AND_ASSERT_MES(r, false, "while creating outs: failed to derive_public_key(" << derivation << ", " << vout_index << ", "<< addresses_and_portions[i].first.m_spend_public_key << ")");

      if (boost::get<cryptonote::txout_to_key>(miner_tx.vout[vout_index].target).key != out_eph_public_key)
      {
        MERROR("Invalid service node reward output");
        return false;
      }
    }

    return true;
  }

  static uint64_t uniform_distribution_portable(std::mt19937_64& mersenne_twister, uint64_t n)
  {
    uint64_t secureMax = mersenne_twister.max() - mersenne_twister.max() % n;
    uint64_t x;
    do x = mersenne_twister(); while (x >= secureMax);
    return  x / (secureMax / n);
  }

  void loki_shuffle(std::vector<size_t>& a, uint64_t seed)
  {
    if (a.size() <= 1) return;
    std::mt19937_64 mersenne_twister(seed);
    for (size_t i = 1; i < a.size(); i++)
    {
      size_t j = (size_t)uniform_distribution_portable(mersenne_twister, i+1);
      if (i != j)
        std::swap(a[i], a[j]);
    }
  }

  void service_node_list::store_quorum_state_from_rewards_list(uint64_t height)
  {
    const crypto::hash block_hash = m_blockchain.get_block_id_by_height(height);
    if (block_hash == crypto::null_hash)
    {
      MERROR("Block height: " << height << " returned null hash");
      return;
    }

    std::vector<crypto::public_key> full_node_list = get_service_nodes_pubkeys();
    std::vector<size_t>                              pub_keys_indexes(full_node_list.size());
    {
      size_t index = 0;
      for (size_t i = 0; i < full_node_list.size(); i++) { pub_keys_indexes[i] = i; }

      // Shuffle indexes
      uint64_t seed = 0;
      std::memcpy(&seed, block_hash.data, std::min(sizeof(seed), sizeof(block_hash.data)));

      loki_shuffle(pub_keys_indexes, seed);
    }

    // Assign indexes from shuffled list into quorum and list of nodes to test

    auto new_state = std::make_shared<quorum_state>();

    {
      std::vector<crypto::public_key>& quorum = new_state->quorum_nodes;
      {
        quorum.resize(std::min(full_node_list.size(), QUORUM_SIZE));
        for (size_t i = 0; i < quorum.size(); i++)
        {
          size_t node_index                   = pub_keys_indexes[i];
          const crypto::public_key &key = full_node_list[node_index];
          quorum[i] = key;
        }
      }

      std::vector<crypto::public_key>& nodes_to_test = new_state->nodes_to_test;
      {
        size_t num_remaining_nodes = pub_keys_indexes.size() - quorum.size();
        size_t num_nodes_to_test   = std::max(num_remaining_nodes/NTH_OF_THE_NETWORK_TO_TEST,
                                              std::min(MIN_NODES_TO_TEST, num_remaining_nodes));

        nodes_to_test.resize(num_nodes_to_test);

        const int pub_keys_offset = quorum.size();
        for (size_t i = 0; i < nodes_to_test.size(); i++)
        {
          size_t node_index             = pub_keys_indexes[pub_keys_offset + i];
          const crypto::public_key &key = full_node_list[node_index];
          nodes_to_test[i]              = key;
        }
      }
    }

    m_quorum_states[height] = new_state;
  }

  //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

  service_node_list::rollback_event::rollback_event(uint64_t block_height, rollback_type type) : m_block_height(block_height), type(type)
  {
  }

  service_node_list::rollback_change::rollback_change(uint64_t block_height, const crypto::public_key& key, const service_node_info& info)
    : service_node_list::rollback_event(block_height, change_type), m_key(key), m_info(info)
  {
  }

  bool service_node_list::rollback_change::apply(std::unordered_map<crypto::public_key, service_node_info>& service_nodes_infos) const
  {
    service_nodes_infos[m_key] = m_info;
    return true;
  }

  service_node_list::rollback_new::rollback_new(uint64_t block_height, const crypto::public_key& key)
    : service_node_list::rollback_event(block_height, new_type), m_key(key)
  {
  }

  bool service_node_list::rollback_new::apply(std::unordered_map<crypto::public_key, service_node_info>& service_nodes_infos) const
  {
    auto iter = service_nodes_infos.find(m_key);
    if (iter == service_nodes_infos.end())
    {
      MERROR("Could not find service node pubkey in rollback new");
      return false;
    }
    service_nodes_infos.erase(iter);
    return true;
  }

  service_node_list::prevent_rollback::prevent_rollback(uint64_t block_height) : service_node_list::rollback_event(block_height, prevent_type)
  {
  }

  bool service_node_list::prevent_rollback::apply(std::unordered_map<crypto::public_key, service_node_info>& service_nodes_infos) const
  {
    MERROR("Unable to rollback any further!");
    return false;
  }

  bool service_node_list::store()
  {

    CHECK_AND_ASSERT_MES(m_db != nullptr, false, "Failed to store service node info, m_db == nullptr");
    data_members_for_serialization data_to_store;
    {
      std::lock_guard<boost::recursive_mutex> lock(m_sn_mutex);

      quorum_state_for_serialization quorum;
      for(const auto& kv_pair : m_quorum_states)
      {
        quorum.height = kv_pair.first;
        quorum.state = *kv_pair.second;
        data_to_store.quorum_states.push_back(quorum);
      }

      node_info_for_serialization info;
      for (const auto& kv_pair : m_service_nodes_infos)
      {
        info.key = kv_pair.first;
        info.info = kv_pair.second;
        data_to_store.infos.push_back(info);
      }

      rollback_event_variant event;
      for (const auto& event_ptr : m_rollback_events)
      {
        switch (event_ptr->type)
        {
          case rollback_event::change_type:
            event = *reinterpret_cast<rollback_change *>(event_ptr.get());
            data_to_store.events.push_back(*reinterpret_cast<rollback_change *>(event_ptr.get()));
            break;
          case rollback_event::new_type:
            event = *reinterpret_cast<rollback_new *>(event_ptr.get());
            data_to_store.events.push_back(*reinterpret_cast<rollback_new *>(event_ptr.get()));
            break;
          case rollback_event::prevent_type:
            event = *reinterpret_cast<prevent_rollback *>(event_ptr.get());
            data_to_store.events.push_back(*reinterpret_cast<prevent_rollback *>(event_ptr.get()));
            break;
          default:
            MERROR("On storing service node data, unknown rollback event type encountered");
            return false;
        }
      }

    }

    data_to_store.height = m_height;

    std::stringstream ss;
    binary_archive<true> ba(ss);

    bool r = ::serialization::serialize(ba, data_to_store);
    CHECK_AND_ASSERT_MES(r, false, "Failed to store service node info: failed to serialize data");

    std::string blob = ss.str();
    m_db->block_txn_start(false/*readonly*/);
    m_db->set_service_node_data(blob);
    m_db->block_txn_stop();

    return true;
  }

  bool service_node_list::load()
  {
    LOG_PRINT_L1("service_node_list::load()");
    clear(false);
    if (!m_db)
    {
      return false;
    }
    std::stringstream ss;

    data_members_for_serialization data_in;
    std::string blob;

    m_db->block_txn_start(true/*readonly*/);
    if (!m_db->get_service_node_data(blob))
    {
      m_db->block_txn_stop();
      return false;
    }
    m_db->block_txn_stop();

    ss << blob;
    binary_archive<false> ba(ss);
    bool r = ::serialization::serialize(ba, data_in);
    CHECK_AND_ASSERT_MES(r, false, "Failed to parse service node data from blob");

    m_height = data_in.height;

    for (const auto& quorum : data_in.quorum_states)
    {
      m_quorum_states[quorum.height] = std::make_shared<quorum_state>(quorum.state);
    }

    for (const auto& info : data_in.infos)
    {
      m_service_nodes_infos[info.key] = info.info;
    }

    for (const auto& event : data_in.events)
    {
      if (event.type() == typeid(rollback_change))
      {
        rollback_change *i = new rollback_change();
        const rollback_change& from = boost::get<rollback_change>(event);
        i->m_block_height = from.m_block_height;
        i->m_key = from.m_key;
        i->m_info = from.m_info;
        i->type = rollback_event::change_type;
        m_rollback_events.push_back(std::unique_ptr<rollback_event>(i));
      }
      else if (event.type() == typeid(rollback_new))
      {
        rollback_new *i = new rollback_new();
        const rollback_new& from = boost::get<rollback_new>(event);
        i->m_block_height = from.m_block_height;
        i->m_key = from.m_key;
        i->type = rollback_event::new_type;
        m_rollback_events.push_back(std::unique_ptr<rollback_event>(i));
      }
      else if (event.type() == typeid(prevent_rollback))
      {
        prevent_rollback *i = new prevent_rollback();
        const prevent_rollback& from = boost::get<prevent_rollback>(event);
        i->m_block_height = from.m_block_height;
        i->type = rollback_event::prevent_type;
        m_rollback_events.push_back(std::unique_ptr<rollback_event>(i));
      }
      else
      {
        MERROR("Unhandled rollback event type in restoring data to service node list.");
        return false;
      }
    }

    MGINFO("Service node data loaded successfully, m_height: " << m_height);
    MGINFO(m_service_nodes_infos.size() << " nodes and " << m_rollback_events.size() << " rollback events loaded.");

    LOG_PRINT_L1("service_node_list::load() returning success");
    return true;
  }

  void service_node_list::clear(bool delete_db_entry)
  {
    m_service_nodes_infos.clear();
    m_rollback_events.clear();

    if (m_db && delete_db_entry)
    {
      m_db->block_txn_start(false/*readonly*/);
      m_db->clear_service_node_data();
      m_db->block_txn_stop();
    }

    m_quorum_states.clear();

    uint64_t hardfork_9_from_height = 0;
    {
      uint32_t window, votes, threshold;
      uint8_t voting;
      m_blockchain.get_hard_fork_voting_info(9, window, votes, threshold, hardfork_9_from_height, voting);
    }
    m_height = hardfork_9_from_height;
  }

  bool convert_registration_args(cryptonote::network_type nettype, std::vector<std::string> args, std::vector<cryptonote::account_public_address>& addresses, std::vector<uint64_t>& portions, uint64_t& portions_for_operator, bool& autostake)
  {
    autostake = false;
    if (!args.empty() && args[0] == "auto")
    {
      autostake = true;
      args.erase(args.begin());
    }

    if (args.size() % 2 == 0 || args.size() < 3)
    {
      MERROR(tr("Usage: [auto] <operator cut> <address> <fraction> [<address> <fraction> [...]]]"));
      return false;
    }
    if ((args.size()-1)/ 2 > MAX_NUMBER_OF_CONTRIBUTORS)
    {
      MERROR(tr("Exceeds the maximum number of contributors, which is ") << MAX_NUMBER_OF_CONTRIBUTORS);
      return false;
    }
    addresses.clear();
    portions.clear();
    try
    {
      portions_for_operator = boost::lexical_cast<uint64_t>(args[0]);
      if (portions_for_operator > STAKING_PORTIONS)
      {
        MERROR(tr("Invalid portion amount: ") << args[0] << tr(". ") << tr("Must be between 0 and ") << STAKING_PORTIONS);
        return false;
      }
    }
    catch (const std::exception &e)
    {
      MERROR(tr("Invalid portion amount: ") << args[0] << tr(". ") << tr("Must be between 0 and ") << STAKING_PORTIONS);
      return false;
    }
    uint64_t portions_left = STAKING_PORTIONS;
    for (size_t i = 1; i < args.size(); i += 2)
    {
      cryptonote::address_parse_info info;
      if (!cryptonote::get_account_address_from_str(info, nettype, args[i]))
      {
        MERROR(tr("failed to parse address"));
        return false;
      }

      if (info.has_payment_id)
      {
        MERROR(tr("can't use a payment id for staking tx"));
        return false;
      }

      if (info.is_subaddress)
      {
        MERROR(tr("can't use a subaddress for staking tx"));
        return false;
      }

      addresses.push_back(info.address);

      try
      {
        uint64_t num_portions = boost::lexical_cast<uint64_t>(args[i+1]);
        uint64_t min_portions = std::min(portions_left, MIN_PORTIONS);
        if (num_portions < min_portions || num_portions > portions_left)
        {
          MERROR(tr("Invalid portion amount: ") << args[i+1] << tr(". ") << tr("The contributors must each have at least 25%, except for the last contributor which may have the remaining amount"));
          return false;
        }
        portions_left -= num_portions;
        portions.push_back(num_portions);
      }
      catch (const std::exception &e)
      {
        MERROR(tr("Invalid portion amount: ") << args[i+1] << tr(". ") << tr("The contributors must each have at least 25%, except for the last contributor which may have the remaining amount"));
        return false;
      }
    }
    return true;
  }

  bool make_registration_cmd(cryptonote::network_type nettype, const std::vector<std::string> args, const crypto::public_key& service_node_pubkey,
                             const crypto::secret_key service_node_key, std::string &cmd, bool make_friendly)
  {

    std::vector<cryptonote::account_public_address> addresses;
    std::vector<uint64_t> portions;
    uint64_t operator_portions;
    bool autostake;
    if (!convert_registration_args(nettype, args, addresses, portions, operator_portions, autostake))
    {
      MERROR(tr("Could not convert registration args"));
      return false;
    }

    uint64_t exp_timestamp = time(nullptr) + (autostake ? STAKING_AUTHORIZATION_EXPIRATION_AUTOSTAKE : STAKING_AUTHORIZATION_EXPIRATION_WINDOW);

    crypto::hash hash;
    bool hashed = cryptonote::get_registration_hash(addresses, operator_portions, portions, exp_timestamp, hash);
    if (!hashed)
    {
      MERROR(tr("Could not make registration hash from addresses and portions"));
      return false;
    }

    crypto::signature signature;
    crypto::generate_signature(hash, service_node_pubkey, service_node_key, signature);

    std::stringstream stream;
    if (make_friendly)
    {
      stream << tr("Run this command in the wallet that will fund this registration:\n\n");
    }

    stream << "register_service_node";
    for (size_t i = 0; i < args.size(); ++i)
    {
      stream << " " << args[i];
    }

    stream << " " << exp_timestamp << " ";
    stream << epee::string_tools::pod_to_hex(service_node_pubkey) << " ";
    stream << epee::string_tools::pod_to_hex(signature);

    if (make_friendly)
    {
      stream << "\n\n";
      time_t tt = exp_timestamp;
      struct tm tm;
#ifdef WIN32
      gmtime_s(&tm, &tt);
#else
      gmtime_r(&tt, &tm);
#endif

      char buffer[128];
      strftime(buffer, sizeof(buffer), "%Y-%m-%d %I:%M:%S %p", &tm);
      stream << tr("This registration expires at ") << buffer << tr(".\n");
      stream << tr("This should be in about 2 weeks, or two years for autostaking.\n");
      stream << tr("If it isn't, check this computer's clock.\n");
      stream << tr("Please submit your registration into the blockchain before this time or it will be invalid.");
    }

    cmd = stream.str();
    return true;
  }

  uint64_t get_staking_requirement_lock_blocks(cryptonote::network_type nettype)
  {
    constexpr static uint32_t STAKING_REQUIREMENT_LOCK_BLOCKS         = 30*24*30;
    constexpr static uint32_t STAKING_REQUIREMENT_LOCK_BLOCKS_TESTNET = 30*24*2;
    constexpr static uint32_t STAKING_REQUIREMENT_LOCK_BLOCKS_FAKENET = 30;

    switch(nettype) {
      case cryptonote::TESTNET: return STAKING_REQUIREMENT_LOCK_BLOCKS_TESTNET;
      case cryptonote::FAKECHAIN: return STAKING_REQUIREMENT_LOCK_BLOCKS_FAKENET;
      default: return STAKING_REQUIREMENT_LOCK_BLOCKS;
    }
  }

  uint64_t get_staking_requirement(cryptonote::network_type m_nettype, uint64_t height)
  {
    if (m_nettype == cryptonote::TESTNET || m_nettype == cryptonote::FAKECHAIN)
      return COIN * 100;

    uint64_t hardfork_height = m_nettype == cryptonote::MAINNET ? 101250 : 96210 /* stagenet */;
    if (height < hardfork_height) height = hardfork_height;

    uint64_t height_adjusted = height - hardfork_height;
    uint64_t base = 10000 * COIN;
    uint64_t variable = (35000.0 * COIN) / loki_exp2(height_adjusted/129600.0);
    uint64_t linear_up = (uint64_t)(5 * COIN * height / 2592) + 8000 * COIN;
    uint64_t flat = 15000 * COIN;
    return std::max(base + variable, height < 3628800 ? linear_up : flat);
  }

  uint64_t portions_to_amount(uint64_t portions, uint64_t staking_requirement)
  {
    uint64_t hi, lo, resulthi, resultlo;
    lo = mul128(staking_requirement, portions, &hi);
    div128_64(hi, lo, STAKING_PORTIONS, &resulthi, &resultlo);
    return resultlo;
  }
}