ton/validator-session/validator-session.cpp

/*
    This file is part of TON Blockchain Library.

    TON Blockchain Library is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    TON Blockchain Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.

    Copyright 2017-2019 Telegram Systems LLP
*/
#include "validator-session.hpp"
#include "td/utils/Random.h"
#include "td/utils/crypto.h"

namespace ton {

namespace validatorsession {

void ValidatorSessionImpl::process_blocks(std::vector<catchain::CatChainBlock *> blocks) {
  VLOG(VALIDATOR_SESSION_DEBUG) << this << ": processing " << blocks.size() << " blocks";
  requested_new_block_ = false;
  requested_new_block_now_ = false;

  for (auto block : blocks) {
    auto e = dynamic_cast<const BlockExtra *>(block->extra());
    CHECK(e != nullptr);
    real_state_ = ValidatorSessionState::merge(description(), real_state_, e->get_ref());
  }

  if (real_state_->cur_round_seqno() != cur_round_) {
    on_new_round(real_state_->cur_round_seqno());
  }

  td::uint32 cnt = 0;
  auto ts = description().get_ts();
  auto att = description().get_attempt_seqno(ts);
  std::vector<tl_object_ptr<ton_api::validatorSession_round_Message>> msgs;

  if (generated_ && !sent_generated_) {
    auto it = blocks_[0].find(generated_block_);
    CHECK(it != blocks_[0].end());

    auto &B = it->second;
    auto file_hash = sha256_bits256(B->data_);
    auto collated_data_file_hash = sha256_bits256(B->collated_data_);
    msgs.emplace_back(create_tl_object<ton_api::validatorSession_message_submittedBlock>(
        cur_round_, B->root_hash_, file_hash, collated_data_file_hash));
    cnt++;
    sent_generated_ = true;
  }

  auto to_approve = real_state_->choose_blocks_to_approve(description(), local_idx());
  for (auto &block : to_approve) {
    auto id = SentBlock::get_block_id(block);
    if (approved_.count(id) && approved_[id].first <= td::Clocks::system()) {
      msgs.emplace_back(create_tl_object<ton_api::validatorSession_message_approvedBlock>(
          cur_round_, id, approved_[id].second.clone()));
      cnt++;
    }
  }
  for (auto &B : pending_reject_) {
    msgs.emplace_back(
        create_tl_object<ton_api::validatorSession_message_rejectedBlock>(cur_round_, B.first, std::move(B.second)));
  }
  pending_reject_.clear();

  if (signed_) {
    bool found = false;
    auto B = real_state_->choose_block_to_sign(description(), local_idx(), found);
    if (found) {
      CHECK(SentBlock::get_block_id(B) == signed_block_);
      msgs.emplace_back(
          create_tl_object<ton_api::validatorSession_message_commit>(cur_round_, signed_block_, std::move(signature_)));
      cnt++;
    }
  }

  for (auto &msg : msgs) {
    VLOG(VALIDATOR_SESSION_INFO) << this << ": applying action: " << msg.get();
    real_state_ = ValidatorSessionState::action(description(), real_state_, local_idx(), att, msg.get());
  }

  if (real_state_->check_need_generate_vote_for(description(), local_idx(), att)) {
    VLOG(VALIDATOR_SESSION_INFO) << this << ": generating VOTEFOR";
    auto msg = real_state_->generate_vote_for(description(), local_idx(), att);
    CHECK(msg);
    real_state_ = ValidatorSessionState::action(description(), real_state_, local_idx(), att, msg.get());
    msgs.push_back(std::move(msg));
  }

  while (true) {
    auto msg = real_state_->create_action(description(), local_idx(), att);
    bool stop = false;
    if (msg->get_id() == ton_api::validatorSession_message_empty::ID) {
      stop = true;
    }
    VLOG(VALIDATOR_SESSION_INFO) << this << ": applying action: " << msg.get();
    real_state_ = ValidatorSessionState::action(description(), real_state_, local_idx(), att, msg.get());
    msgs.emplace_back(std::move(msg));
    cnt++;
    if (stop) {
      break;
    }
  }

  real_state_ = ValidatorSessionState::move_to_persistent(description(), real_state_);

  VLOG(VALIDATOR_SESSION_DEBUG) << this << ": created block: root_hash=" << real_state_->get_hash(description());

  auto payload = create_tl_object<ton_api::validatorSession_blockUpdate>(ts, std::move(msgs),
                                                                         real_state_->get_hash(description()));
  td::actor::send_closure(catchain_, &catchain::CatChain::processed_block, serialize_tl_object(payload, true));

  auto round = real_state_->cur_round_seqno();
  if (round > cur_round_) {
    on_new_round(round);
  }

  virtual_state_ = ValidatorSessionState::merge(description(), virtual_state_, real_state_);
  virtual_state_ = ValidatorSessionState::move_to_persistent(description(), virtual_state_);
  description().clear_temp_memory();
}

void ValidatorSessionImpl::finished_processing() {
  if (virtual_state_->get_hash(description()) != real_state_->get_hash(description())) {
    VLOG(VALIDATOR_SESSION_WARNING) << this << ": hash mismatch (maybe some node blamed)";
  }
  virtual_state_ = real_state_;
  check_all();
}

void ValidatorSessionImpl::preprocess_block(catchain::CatChainBlock *block) {
  auto start_time = td::Timestamp::now();
  td::PerfWarningTimer p_timer{"Loong block preprocess", 0.1};
  td::PerfWarningTimer q_timer{"Looong block preprocess", 0.1};

  auto prev = block->prev();
  const ValidatorSessionState *state;
  if (prev) {
    auto e = dynamic_cast<const BlockExtra *>(prev->extra());
    CHECK(e != nullptr);
    state = e->get_ref();
  } else {
    state = ValidatorSessionState::create(description());
  }
  auto deps = block->deps();
  for (auto b : deps) {
    auto e = dynamic_cast<const BlockExtra *>(b->extra());
    CHECK(e != nullptr);
    state = ValidatorSessionState::merge(description(), state, e->get_ref());
  }

  if (block->payload().size() != 0 || deps.size() != 0) {
    auto R = fetch_tl_object<ton_api::validatorSession_blockUpdate>(block->payload().clone(), true);
    if (!R.is_error()) {
      auto B = R.move_as_ok();
      auto att = description().get_attempt_seqno(B->ts_);
      for (auto &msg : B->actions_) {
        VLOG(VALIDATOR_SESSION_INFO) << this << "[node " << description().get_source_id(block->source()) << "][block "
                                     << block->hash() << "]: applying action " << msg.get();
        state = ValidatorSessionState::action(description(), state, block->source(), att, msg.get());
      }
      state = ValidatorSessionState::make_all(description(), state, block->source(), att);
      if (state->get_hash(description()) != static_cast<td::uint32>(B->state_)) {
        VLOG(VALIDATOR_SESSION_WARNING) << this << "[node " << description().get_source_id(block->source())
                                        << "][block " << block->hash()
                                        << "]: state hash mismatch: computed=" << state->get_hash(description())
                                        << " received=" << B->state_;
        for (auto &msg : B->actions_) {
          VLOG(VALIDATOR_SESSION_WARNING) << this << "[node " << description().get_source_id(block->source())
                                          << "][block " << block->hash() << "]: applied action " << msg.get();
        }
      }
    } else {
      VLOG(VALIDATOR_SESSION_WARNING) << this << "[node " << description().get_source_id(block->source()) << "][block "
                                      << block->hash() << "]: failed to parse: " << R.move_as_error();
      state = ValidatorSessionState::make_all(description(), state, block->source(), state->get_ts(block->source()));
    }
  }
  q_timer.reset();
  state = ValidatorSessionState::move_to_persistent(description(), state);
  block->set_extra(std::make_unique<BlockExtra>(state));
  if (block->source() == local_idx() && !catchain_started_) {
    real_state_ = state;
  }
  virtual_state_ = ValidatorSessionState::merge(description(), virtual_state_, state);
  virtual_state_ = ValidatorSessionState::move_to_persistent(description(), virtual_state_);
  description().clear_temp_memory();
  if (real_state_->cur_round_seqno() != cur_round_) {
    on_new_round(real_state_->cur_round_seqno());
  }
  check_all();
  VLOG(VALIDATOR_SESSION_DEBUG) << this << ": preprocessed block " << block->hash() << " in "
                                << static_cast<td::uint32>(1000 * (td::Timestamp::now().at() - start_time.at()))
                                << "ms: state=" << state->get_hash(description());
}

void ValidatorSessionImpl::process_broadcast(PublicKeyHash src, td::BufferSlice data) {
  auto src_idx = description().get_source_idx(src);
  auto R = fetch_tl_object<ton_api::validatorSession_candidate>(data.clone(), true);
  if (R.is_error()) {
    VLOG(VALIDATOR_SESSION_WARNING) << this << "[node " << src << "][broadcast " << sha256_bits256(data.as_slice())
                                    << "]: failed to parse: " << R.move_as_error();
    return;
  }
  auto candidate = R.move_as_ok();
  if (PublicKeyHash{candidate->src_} != src) {
    VLOG(VALIDATOR_SESSION_WARNING) << this << "[node " << src << "][broadcast " << sha256_bits256(data.as_slice())
                                    << "]: source mismatch";
    return;
  }
  if (candidate->data_.size() > description().opts().max_block_size ||
      candidate->collated_data_.size() > description().opts().max_collated_data_size) {
    VLOG(VALIDATOR_SESSION_WARNING) << this << "[node " << src << "][broadcast " << sha256_bits256(data.as_slice())
                                    << "]: too big broadcast size=" << candidate->data_.size() << " "
                                    << candidate->collated_data_.size();
    return;
  }

  auto file_hash = sha256_bits256(candidate->data_.as_slice());
  auto collated_data_file_hash = sha256_bits256(candidate->collated_data_.as_slice());
  auto block_round = static_cast<td::uint32>(candidate->round_);
  auto block_id = description().candidate_id(src_idx, candidate->root_hash_, file_hash, collated_data_file_hash);

  if (block_round < cur_round_ || block_round >= cur_round_ + blocks_.size()) {
    VLOG(VALIDATOR_SESSION_NOTICE) << this << "[node " << src << "][broadcast " << block_id
                                   << "]: bad round=" << block_round << " cur_round" << cur_round_;
    return;
  }
  auto it = blocks_[block_round - cur_round_].find(block_id);
  if (it != blocks_[block_round - cur_round_].end()) {
    VLOG(VALIDATOR_SESSION_INFO) << this << "[node " << src << "][broadcast " << block_id << "]: duplicate";
    return;
  }

  auto priority = description().get_node_priority(src_idx, block_round);
  if (priority < 0) {
    VLOG(VALIDATOR_SESSION_WARNING) << this << "[node " << src << "][broadcast " << block_id
                                    << "]: source is not allowed to generate blocks in this round";
    return;
  }

  blocks_[block_round - cur_round_][block_id] = std::move(candidate);

  VLOG(VALIDATOR_SESSION_WARNING) << this << ": received broadcast " << block_id;
  if (block_round != cur_round_) {
    return;
  }

  CHECK(!pending_approve_.count(block_id));
  CHECK(!approved_.count(block_id));
  CHECK(!pending_reject_.count(block_id));
  CHECK(!rejected_.count(block_id));

  auto v = virtual_state_->choose_blocks_to_approve(description(), local_idx());
  for (auto &b : v) {
    if (b && SentBlock::get_block_id(b) == block_id) {
      try_approve_block(b);
      break;
    }
  }
}

void ValidatorSessionImpl::process_message(PublicKeyHash src, td::BufferSlice data) {
}

void ValidatorSessionImpl::process_query(PublicKeyHash src, td::BufferSlice data,
                                         td::Promise<td::BufferSlice> promise) {
  if (!started_) {
    promise.set_error(td::Status::Error(ErrorCode::notready, "not started"));
    return;
  }
  auto F = fetch_tl_object<ton_api::validatorSession_downloadCandidate>(std::move(data), true);
  if (F.is_error()) {
    promise.set_error(F.move_as_error_prefix("validator session: cannot parse query: "));
    return;
  }
  auto f = F.move_as_ok();

  auto round_id = static_cast<td::uint32>(f->round_);
  if (round_id > real_state_->cur_round_seqno()) {
    promise.set_error(td::Status::Error(ErrorCode::notready, "too big round id"));
    return;
  }
  const SentBlock *block = nullptr;
  auto id = description().candidate_id(description().get_source_idx(PublicKeyHash{f->id_->src_}), f->id_->root_hash_,
                                       f->id_->file_hash_, f->id_->collated_data_file_hash_);
  if (round_id < real_state_->cur_round_seqno()) {
    block = real_state_->get_committed_block(description(), round_id);
    if (!block || SentBlock::get_block_id(block) != id) {
      promise.set_error(td::Status::Error(ErrorCode::notready, "wrong block in old round"));
      return;
    }
  } else {
    CHECK(round_id == real_state_->cur_round_seqno());
    bool found;
    block = real_state_->get_block(description(), id, found);
    if (!found || !block) {
      promise.set_error(td::Status::Error(ErrorCode::notready, "wrong block"));
      return;
    }
    if (!real_state_->check_block_is_approved_by(description(), local_idx(), id)) {
      promise.set_error(td::Status::Error(ErrorCode::notready, "not approved block"));
      return;
    }
  }
  CHECK(block);

  auto P = td::PromiseCreator::lambda(
      [promise = std::move(promise), src = f->id_->src_, round_id](td::Result<BlockCandidate> R) mutable {
        if (R.is_error()) {
          promise.set_error(R.move_as_error_prefix("failed to get candidate: "));
        } else {
          auto c = R.move_as_ok();
          auto obj = create_tl_object<ton_api::validatorSession_candidate>(
              src, round_id, c.id.root_hash, std::move(c.data), std::move(c.collated_data));
          promise.set_value(serialize_tl_object(obj, true));
        }
      });

  callback_->get_approved_candidate(description().get_source_public_key(block->get_src_idx()), f->id_->root_hash_,
                                    f->id_->file_hash_, f->id_->collated_data_file_hash_, std::move(P));
}

void ValidatorSessionImpl::candidate_decision_fail(td::uint32 round, ValidatorSessionCandidateId hash,
                                                   std::string result, td::BufferSlice proof) {
  if (round != cur_round_) {
    return;
  }
  LOG(ERROR) << this << ": failed candidate " << hash << ": " << result;
  pending_approve_.erase(hash);
  pending_reject_.emplace(hash, td::BufferSlice{result});
  rejected_.insert(hash);
}

void ValidatorSessionImpl::candidate_decision_ok(td::uint32 round, ValidatorSessionCandidateId hash, RootHash root_hash,
                                                 FileHash file_hash, td::uint32 ok_from) {
  if (round != cur_round_) {
    return;
  }

  LOG(INFO) << this << ": approved candidate " << hash;

  auto obj = create_tl_object<ton_api::ton_blockIdApprove>(root_hash, file_hash);
  auto data = serialize_tl_object(obj, true);

  auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), print_id = print_id(), hash, ok_from,
                                       round = cur_round_](td::Result<td::BufferSlice> R) {
    if (R.is_error()) {
      LOG(FATAL) << print_id << ": failed to sign: " << R.move_as_error();
    } else {
      td::actor::send_closure(SelfId, &ValidatorSessionImpl::candidate_approved_signed, round, hash, ok_from,
                              R.move_as_ok());
    }
  });

  td::actor::send_closure(keyring_, &keyring::Keyring::sign_message, local_id(), std::move(data), std::move(P));
}

void ValidatorSessionImpl::candidate_approved_signed(td::uint32 round, ValidatorSessionCandidateId hash,
                                                     td::uint32 ok_from, td::BufferSlice signature) {
  pending_approve_.erase(hash);
  approved_[hash] = std::pair<td::uint32, td::BufferSlice>{ok_from, std::move(signature)};

  if (ok_from <= td::Clocks::system()) {
    request_new_block(false);
  } else {
    LOG(WARNING) << "too new block. ts=" << ok_from;
    alarm_timestamp().relax(td::Timestamp::at_unix(ok_from));
  }
}

void ValidatorSessionImpl::generated_block(td::uint32 round, ValidatorSessionCandidateId root_hash,
                                           td::BufferSlice data, td::BufferSlice collated_data) {
  if (round != cur_round_) {
    return;
  }
  if (data.size() > description().opts().max_block_size ||
      collated_data.size() > description().opts().max_collated_data_size) {
    LOG(ERROR) << this << ": generated candidate is too big. Dropping. size=" << data.size() << " "
               << collated_data.size();
    return;
  }
  auto file_hash = sha256_bits256(data.as_slice());
  auto collated_data_file_hash = sha256_bits256(collated_data.as_slice());

  auto b = create_tl_object<ton_api::validatorSession_candidate>(local_id().tl(), round, root_hash, std::move(data),
                                                                 std::move(collated_data));

  auto B = serialize_tl_object(b, true);

  auto block_id = description().candidate_id(local_idx(), root_hash, file_hash, collated_data_file_hash);

  td::actor::send_closure(catchain_, &catchain::CatChain::send_broadcast, std::move(B));

  blocks_[0].emplace(block_id, std::move(b));
  pending_generate_ = false;
  generated_ = true;
  generated_block_ = block_id;

  request_new_block(true);
}

void ValidatorSessionImpl::signed_block(td::uint32 round, ValidatorSessionCandidateId hash, td::BufferSlice signature) {
  if (round != cur_round_) {
    return;
  }
  pending_sign_ = false;
  signed_ = true;
  signed_block_ = hash;
  signature_ = std::move(signature);

  request_new_block(false);
}

void ValidatorSessionImpl::alarm() {
  alarm_timestamp() = td::Timestamp::never();
  check_all();
}

void ValidatorSessionImpl::check_vote_for_slot(td::uint32 att) {
  if (!catchain_started_) {
    return;
  }
  if (!started_) {
    return;
  }
  if (virtual_state_->check_need_generate_vote_for(description(), local_idx(), att)) {
    request_new_block(false);
  }
}

void ValidatorSessionImpl::check_generate_slot() {
  if (!catchain_started_) {
    return;
  }
  if (!generated_ && !pending_generate_ && started_) {
    if (real_state_->check_block_is_sent_by(description(), local_idx())) {
      generated_ = true;
      sent_generated_ = true;
      return;
    }
    auto priority = description().get_node_priority(local_idx(), cur_round_);
    if (priority >= 0) {
      auto t = td::Timestamp::at(round_started_at_.at() + description().get_delay(priority));
      if (t.is_in_past()) {
        pending_generate_ = true;

        td::PerfWarningTimer timer{"too long block generation", 1.0};

        auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), print_id = print_id(), timer = std::move(timer),
                                             round = cur_round_](td::Result<BlockCandidate> R) {
          if (R.is_ok()) {
            auto c = R.move_as_ok();
            td::actor::send_closure(SelfId, &ValidatorSessionImpl::generated_block, round, c.id.root_hash,
                                    c.data.clone(), c.collated_data.clone());
          } else {
            LOG(WARNING) << print_id << ": failed to generate block candidate: " << R.move_as_error();
          }
        });
        callback_->on_generate_slot(cur_round_, std::move(P));
      } else {
        alarm_timestamp().relax(t);
      }
    }
  }
}

void ValidatorSessionImpl::try_approve_block(const SentBlock *block) {
  auto block_id = SentBlock::get_block_id(block);
  {
    auto it = approved_.find(block_id);
    if (it != approved_.end()) {
      if (it->second.first <= td::Clocks::system()) {
        request_new_block(false);
      } else {
        alarm_timestamp().relax(td::Timestamp::at_unix(it->second.first));
      }
      return;
    }
  }
  if (pending_approve_.count(block_id) || rejected_.count(block_id)) {
    return;
  }

  auto delay = block ? description().get_delay(description().get_node_priority(block->get_src_idx(), cur_round_))
                     : description().get_empty_block_delay();
  auto T = td::Timestamp::at(round_started_at_.at() + delay);
  if (!T.is_in_past()) {
    alarm_timestamp().relax(T);
    return;
  }

  if (block) {
    auto T = td::Timestamp::at(round_started_at_.at() + description().get_delay(block->get_src_idx()) + 2.0);
    auto it = blocks_[0].find(block_id);

    if (it != blocks_[0].end()) {
      td::PerfWarningTimer timer{"too long block validation", 1.0};
      auto &B = it->second;

      auto P = td::PromiseCreator::lambda([round = cur_round_, hash = block_id, root_hash = block->get_root_hash(),
                                           file_hash = block->get_file_hash(), timer = std::move(timer),
                                           SelfId = actor_id(this)](td::Result<CandidateDecision> res) {
        auto R = res.move_as_ok();
        if (R.is_ok()) {
          td::actor::send_closure(SelfId, &ValidatorSessionImpl::candidate_decision_ok, round, hash, root_hash,
                                  file_hash, R.ok_from());
        } else {
          td::actor::send_closure(SelfId, &ValidatorSessionImpl::candidate_decision_fail, round, hash, R.reason(),
                                  R.proof());
        }
      });
      pending_approve_.insert(block_id);
      CHECK(static_cast<td::int32>(cur_round_) == B->round_);

      callback_->on_candidate(cur_round_, description().get_source_public_key(block->get_src_idx()), B->root_hash_,
                              B->data_.clone(), B->collated_data_.clone(), std::move(P));
    } else if (T.is_in_past()) {
      if (!active_requests_.count(block_id)) {
        auto v = virtual_state_->get_block_approvers(description(), block_id);
        if (v.size() > 0) {
          auto id = description().get_source_id(v[td::Random::fast(0, static_cast<td::int32>(v.size() - 1))]);
          auto src_id = description().get_source_id(block->get_src_idx());
          active_requests_.insert(block_id);
          auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), id, src_id, print_id = print_id(),
                                               hash = block_id, round = cur_round_](td::Result<td::BufferSlice> R) {
            td::actor::send_closure(SelfId, &ValidatorSessionImpl::end_request, round, hash);
            if (R.is_error()) {
              VLOG(VALIDATOR_SESSION_WARNING)
                  << print_id << ": failed to get candidate " << hash << " from " << id << ": " << R.move_as_error();
            } else {
              td::actor::send_closure(SelfId, &ValidatorSessionImpl::process_broadcast, src_id, R.move_as_ok());
            }
          });

          get_broadcast_p2p(id, block->get_file_hash(), block->get_collated_data_file_hash(),
                            description().get_source_id(block->get_src_idx()), cur_round_, block->get_root_hash(),
                            std::move(P), td::Timestamp::in(2.0));
        } else {
          LOG(VALIDATOR_SESSION_DEBUG) << this << ": no nodes to download candidate " << block << " from";
        }
      }
    } else {
      alarm_timestamp().relax(T);
    }
  } else {
    approved_[block_id] = std::pair<td::uint32, td::BufferSlice>{0, td::BufferSlice{}};

    request_new_block(false);
  }
}

void ValidatorSessionImpl::get_broadcast_p2p(PublicKeyHash node, ValidatorSessionFileHash file_hash,
                                             ValidatorSessionCollatedDataFileHash collated_data_file_hash,
                                             PublicKeyHash src, td::uint32 round, ValidatorSessionRootHash root_hash,
                                             td::Promise<td::BufferSlice> promise, td::Timestamp timeout) {
  if (timeout.is_in_past()) {
    promise.set_error(td::Status::Error(ErrorCode::timeout, "timeout"));
    return;
  }

  auto obj = create_tl_object<ton_api::validatorSession_downloadCandidate>(
      round,
      create_tl_object<ton_api::validatorSession_candidateId>(src.tl(), root_hash, file_hash, collated_data_file_hash));

  td::actor::send_closure(catchain_, &catchain::CatChain::send_query_via, node, "download candidate",
                          std::move(promise), timeout, serialize_tl_object(obj, true),
                          description().opts().max_block_size + description().opts().max_collated_data_size + 1024,
                          rldp_);
}

void ValidatorSessionImpl::check_sign_slot() {
  if (!catchain_started_) {
    return;
  }
  if (pending_sign_ || !started_) {
    return;
  }

  if (real_state_->check_block_is_signed_by(description(), local_idx())) {
    signed_ = true;
    return;
  }
  if (signed_) {
    request_new_block(false);
    return;
  }
  auto found = false;
  auto B = virtual_state_->choose_block_to_sign(description(), local_idx(), found);
  if (found) {
    if (!B) {
      signed_ = true;
      signed_block_ = skip_round_candidate_id();

      request_new_block(false);
    } else {
      pending_sign_ = true;

      auto obj = create_tl_object<ton_api::ton_blockId>(B->get_root_hash(), B->get_file_hash());
      auto data = serialize_tl_object(obj, true);

      auto P =
          td::PromiseCreator::lambda([SelfId = actor_id(this), print_id = print_id(), hash = SentBlock::get_block_id(B),
                                      round = cur_round_](td::Result<td::BufferSlice> R) {
            if (R.is_error()) {
              LOG(FATAL) << print_id << ": failed to sign: " << R.move_as_error();
            } else {
              td::actor::send_closure(SelfId, &ValidatorSessionImpl::signed_block, round, hash, R.move_as_ok());
            }
          });

      td::actor::send_closure(keyring_, &keyring::Keyring::sign_message, local_id(), std::move(data), std::move(P));
    }
  }
}

void ValidatorSessionImpl::check_approve() {
  if (!catchain_started_) {
    return;
  }
  if (!started_) {
    return;
  }
  auto to_approve = virtual_state_->choose_blocks_to_approve(description(), local_idx());
  for (auto &block : to_approve) {
    try_approve_block(block);
  }
}

void ValidatorSessionImpl::check_action(td::uint32 att) {
  if (!catchain_started_) {
    return;
  }
  if (!requested_new_block_) {
    auto action = virtual_state_->create_action(description(), local_idx(), att);
    if (action && action->get_id() != ton_api::validatorSession_message_empty::ID) {
      request_new_block(false);
    }
  }
}

void ValidatorSessionImpl::check_all() {
  if (!catchain_started_) {
    return;
  }
  if (virtual_state_->cur_round_seqno() != cur_round_) {
    request_new_block(false);
    return;
  }
  if (round_debug_at_.is_in_past()) {
    td::BufferSlice buf{10000};
    td::StringBuilder sb{buf.as_slice()};
    real_state_->dump_cur_attempt(description(), sb);
    virtual_state_->dump_cur_attempt(description(), sb);
    auto to_approve = virtual_state_->choose_blocks_to_approve(description(), local_idx());
    sb << "to approve: \n";
    for (auto &B : to_approve) {
      if (B) {
        auto block_id = SentBlock::get_block_id(B);
        auto pending = pending_approve_.count(block_id) == 1;
        auto rejected = rejected_.count(block_id) == 1;
        auto accepted = approved_.count(block_id) == 1;
        sb << "    " << block_id << " pending:  " << pending << " rejected: " << rejected << " accepted: " << accepted
           << "\n";
      } else {
        sb << "    SKIP\n";
      }
    }
    LOG(ERROR) << sb.as_cslice();
    round_debug_at_ = td::Timestamp::in(60.0);
  }
  auto att = description().get_attempt_seqno(description().get_ts());
  check_sign_slot();
  check_approve();
  check_generate_slot();
  check_action(att);
  check_vote_for_slot(att);
  alarm_timestamp().relax(round_debug_at_);
  alarm_timestamp().relax(description().attempt_start_at(att + 1));
}

void ValidatorSessionImpl::request_new_block(bool now) {
  if (requested_new_block_now_) {
    return;
  }
  if (!now && requested_new_block_) {
    return;
  }
  requested_new_block_ = true;
  if (now) {
    requested_new_block_now_ = true;
    td::actor::send_closure(catchain_, &catchain::CatChain::need_new_block, td::Timestamp::now());
  } else {
    double lambda = 10.0 / description().get_total_nodes();
    double x = -1 / lambda * log(td::Random::fast(1, 999) * 0.001);
    if (x > 0.5) {
      x = 0.5;
    }
    td::actor::send_closure(catchain_, &catchain::CatChain::need_new_block, td::Timestamp::in(x));
  }
}

void ValidatorSessionImpl::on_new_round(td::uint32 round) {
  if (round != 0) {
    CHECK(cur_round_ < round);
    pending_generate_ = false;
    generated_ = false;
    sent_generated_ = false;

    pending_approve_.clear();
    rejected_.clear();
    pending_reject_.clear();
    approved_.clear();

    pending_sign_ = false;
    signed_ = false;
    signature_ = td::BufferSlice{};
    signed_block_ = skip_round_candidate_id();

    active_requests_.clear();
  }

  while (cur_round_ < round) {
    auto block = real_state_->get_committed_block(description(), cur_round_);
    //CHECK(block);
    auto sigs = real_state_->get_committed_block_signatures(description(), cur_round_);
    CHECK(sigs);
    auto approve_sigs = real_state_->get_committed_block_approve_signatures(description(), cur_round_);
    CHECK(approve_sigs);

    std::vector<std::pair<PublicKeyHash, td::BufferSlice>> export_sigs;
    CHECK(sigs->size() == description().get_total_nodes());
    for (td::uint32 i = 0; i < description().get_total_nodes(); i++) {
      auto sig = sigs->at(i);
      if (sig) {
        CHECK(description().is_persistent(sig));
        export_sigs.emplace_back(description().get_source_id(i), sig->value().clone());
      }
    }

    std::vector<std::pair<PublicKeyHash, td::BufferSlice>> export_approve_sigs;
    CHECK(approve_sigs->size() == description().get_total_nodes());
    for (td::uint32 i = 0; i < description().get_total_nodes(); i++) {
      auto sig = approve_sigs->at(i);
      if (sig) {
        CHECK(description().is_persistent(sig));
        export_approve_sigs.emplace_back(description().get_source_id(i), sig->value().clone());
      }
    }

    auto it = blocks_[0].find(SentBlock::get_block_id(block));
    if (!block) {
      callback_->on_block_skipped(cur_round_);
    } else if (it == blocks_[0].end()) {
      callback_->on_block_committed(cur_round_, description().get_source_public_key(block->get_src_idx()),
                                    block->get_root_hash(), block->get_file_hash(), td::BufferSlice(),
                                    std::move(export_sigs), std::move(export_approve_sigs));
    } else {
      callback_->on_block_committed(cur_round_, description().get_source_public_key(block->get_src_idx()),
                                    block->get_root_hash(), block->get_file_hash(), it->second->data_.clone(),
                                    std::move(export_sigs), std::move(export_approve_sigs));
    }
    cur_round_++;
    for (size_t i = 0; i < blocks_.size() - 1; i++) {
      blocks_[i] = std::move(blocks_[i + 1]);
    }
    blocks_[blocks_.size() - 1].clear();
  }

  round_started_at_ = td::Timestamp::now();
  round_debug_at_ = td::Timestamp::in(60.0);
  check_all();
}

void ValidatorSessionImpl::on_catchain_started() {
  catchain_started_ = true;

  auto X = virtual_state_->get_blocks_approved_by(description(), local_idx());

  for (auto &x : X) {
    if (x) {
      auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), round = virtual_state_->cur_round_seqno(),
                                           src = description().get_source_id(x->get_src_idx()),
                                           root_hash = x->get_root_hash()](td::Result<BlockCandidate> R) {
        if (R.is_error()) {
          LOG(ERROR) << "failed to get candidate: " << R.move_as_error();
        } else {
          auto B = R.move_as_ok();
          auto broadcast = create_tl_object<ton_api::validatorSession_candidate>(
              src.tl(), round, root_hash, std::move(B.data), std::move(B.collated_data));
          td::actor::send_closure(SelfId, &ValidatorSessionImpl::process_broadcast, src,
                                  serialize_tl_object(broadcast, true));
        }
      });
      callback_->get_approved_candidate(description().get_source_public_key(x->get_src_idx()), x->get_root_hash(),
                                        x->get_file_hash(), x->get_collated_data_file_hash(), std::move(P));
    }
  }

  check_all();
}

ValidatorSessionImpl::ValidatorSessionImpl(catchain::CatChainSessionId session_id, ValidatorSessionOptions opts,
                                           PublicKeyHash local_id, std::vector<ValidatorSessionNode> nodes,
                                           std::unique_ptr<Callback> callback,
                                           td::actor::ActorId<keyring::Keyring> keyring,
                                           td::actor::ActorId<adnl::Adnl> adnl, td::actor::ActorId<rldp::Rldp> rldp,
                                           td::actor::ActorId<overlay::Overlays> overlays, std::string db_root)
    : unique_hash_(session_id)
    , callback_(std::move(callback))
    , db_root_(db_root)
    , keyring_(keyring)
    , adnl_(adnl)
    , rldp_(rldp)
    , overlay_manager_(overlays) {
  description_ = ValidatorSessionDescription::create(std::move(opts), nodes, local_id);
}

void ValidatorSessionImpl::start() {
  started_ = true;
  VLOG(VALIDATOR_SESSION_NOTICE) << this << ": started";

  auto w = description().export_catchain_nodes();

  catchain_ = catchain::CatChain::create(
      make_catchain_callback(),
      catchain::CatChainOptions{description().opts().catchain_idle_timeout, description().opts().catchain_max_deps},
      keyring_, adnl_, overlay_manager_, std::move(w), local_id(), unique_hash_, db_root_);

  check_all();
}

void ValidatorSessionImpl::destroy() {
  if (!catchain_.empty()) {
    td::actor::send_closure(catchain_, &catchain::CatChain::destroy);
    catchain_.release();
  }
  stop();
}

void ValidatorSessionImpl::start_up() {
  CHECK(!rldp_.empty());
  cur_round_ = 0;
  round_started_at_ = td::Timestamp::now();
  round_debug_at_ = td::Timestamp::in(60.0);
  real_state_ = ValidatorSessionState::create(description());
  real_state_ = ValidatorSessionState::move_to_persistent(description(), real_state_);
  virtual_state_ = real_state_;

  check_all();
  td::actor::send_closure(rldp_, &rldp::Rldp::add_id, description().get_source_adnl_id(local_idx()));
}

td::actor::ActorOwn<ValidatorSession> ValidatorSession::create(
    catchain::CatChainSessionId session_id, ValidatorSessionOptions opts, PublicKeyHash local_id,
    std::vector<ValidatorSessionNode> nodes, std::unique_ptr<Callback> callback,
    td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
    td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<overlay::Overlays> overlays, std::string db_root) {
  return td::actor::create_actor<ValidatorSessionImpl>("session", session_id, std::move(opts), local_id,
                                                       std::move(nodes), std::move(callback), keyring, adnl, rldp,
                                                       overlays, db_root);
}

td::Bits256 ValidatorSessionOptions::get_hash() const {
  return create_hash_tl_object<ton_api::validatorSession_config>(
      catchain_idle_timeout, catchain_max_deps, round_candidates, next_candidate_delay, round_attempt_duration,
      max_round_attempts, max_block_size, max_collated_data_size);
}

ValidatorSessionOptions::ValidatorSessionOptions(const ValidatorSessionConfig &conf) {
  CHECK(!conf.proto_version);
  catchain_idle_timeout = conf.catchain_idle_timeout;
  catchain_max_deps = conf.catchain_max_deps;
  max_block_size = conf.max_block_size;
  max_collated_data_size = conf.max_collated_data_size;
  max_round_attempts = conf.max_round_attempts;
  next_candidate_delay = conf.next_candidate_delay;
  round_attempt_duration = conf.round_attempt_duration;
  round_candidates = conf.round_candidates;
}

}  // namespace validatorsession

}  // namespace ton