dash/src/llmq/quorums_utils.cpp

// Copyright (c) 2018 The Dash Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "quorums_utils.h"

#include "chainparams.h"
#include "random.h"

namespace llmq
{

std::vector<CDeterministicMNCPtr> CLLMQUtils::GetAllQuorumMembers(Consensus::LLMQType llmqType, const uint256& blockHash)
{
    auto& params = Params().GetConsensus().llmqs.at(llmqType);
    auto allMns = deterministicMNManager->GetListForBlock(blockHash);
    auto modifier = ::SerializeHash(std::make_pair((uint8_t)llmqType, blockHash));
    return allMns.CalculateQuorum(params.size, modifier);
}

uint256 CLLMQUtils::BuildCommitmentHash(uint8_t llmqType, const uint256& blockHash, const std::vector<bool>& validMembers, const CBLSPublicKey& pubKey, const uint256& vvecHash)
{
    CHashWriter hw(SER_NETWORK, 0);
    hw << llmqType;
    hw << blockHash;
    hw << DYNBITSET(validMembers);
    hw << pubKey;
    hw << vvecHash;
    return hw.GetHash();
}

std::set<CService> CLLMQUtils::GetQuorumConnections(Consensus::LLMQType llmqType, const uint256& blockHash, const uint256& forMember)
{
    auto& params = Params().GetConsensus().llmqs.at(llmqType);

    auto mns = GetAllQuorumMembers(llmqType, blockHash);
    std::set<CService> result;
    for (size_t i = 0; i < mns.size(); i++) {
        auto& dmn = mns[i];
        if (dmn->proTxHash == forMember) {
            for (int n = 0; n < params.neighborConnections; n++) {
                size_t idx = (i + 1 + n) % mns.size();
                auto& otherDmn = mns[idx];
                if (otherDmn == dmn) {
                    continue;
                }
                result.emplace(otherDmn->pdmnState->addr);
            }
            size_t startIdx = i + mns.size() / 2;
            startIdx -= (params.diagonalConnections / 2) * params.neighborConnections;
            startIdx %= mns.size();
            for (int n = 0; n < params.diagonalConnections; n++) {
                size_t idx = startIdx + n * params.neighborConnections;
                idx %= mns.size();
                auto& otherDmn = mns[idx];
                if (otherDmn == dmn) {
                    continue;
                }
                result.emplace(otherDmn->pdmnState->addr);
            }
        }
    }
    return result;
}

std::set<size_t> CLLMQUtils::CalcDeterministicWatchConnections(Consensus::LLMQType llmqType, const uint256& blockHash, size_t memberCount, size_t connectionCount)
{
    static uint256 qwatchConnectionSeed;
    static std::atomic<bool> qwatchConnectionSeedGenerated{false};
    static CCriticalSection qwatchConnectionSeedCs;
    if (!qwatchConnectionSeedGenerated) {
        LOCK(qwatchConnectionSeedCs);
        if (!qwatchConnectionSeedGenerated) {
            qwatchConnectionSeed = GetRandHash();
            qwatchConnectionSeedGenerated = true;
        }
    }

    std::set<size_t> result;
    uint256 rnd = qwatchConnectionSeed;
    for (size_t i = 0; i < connectionCount; i++) {
        rnd = ::SerializeHash(std::make_pair(rnd, std::make_pair((uint8_t)llmqType, blockHash)));
        result.emplace(rnd.GetUint64(0) % memberCount);
    }
    return result;
}

}