zcashd/src/timedata.cpp

// Copyright (c) 2014 The Bitcoin Core developers
// Copyright (c) 2020-2023 The Zcash developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://www.opensource.org/licenses/mit-license.php .

#include "timedata.h"

#include "netbase.h"
#include "sync.h"
#include "ui_interface.h"
#include "util/system.h"
#include "util/strencodings.h"
#include "warnings.h"


CTimeWarning timeWarning;

/**
 * Warn if we have seen TIMEDATA_WARNING_SAMPLES peer times, in the version messages of the
 * first TIMEDATA_MAX_SAMPLES unique (by IP address) peers that connect, that are more than
 * TIMEDATA_WARNING_THRESHOLD seconds but less than TIMEDATA_IGNORE_THRESHOLD seconds away
 * from local time.
 */

int64_t CTimeWarning::AddTimeData(const CNetAddr& ip, int64_t nTime, int64_t now)
{
    assert(now >= 0 && now <= INT64_MAX - TIMEDATA_IGNORE_THRESHOLD);

    if (nTime <= now - TIMEDATA_IGNORE_THRESHOLD || nTime >= now + TIMEDATA_IGNORE_THRESHOLD) {
        return 0;
    }

    int64_t nTimeOffset = nTime - now;

    LOCK(cs);
    // Ignore duplicate IPs.
    if (setKnown.size() == TIMEDATA_MAX_SAMPLES || !setKnown.insert(ip).second) {
        return nTimeOffset;
    }

    LogPrint("net","added time data, samples %d, offset %+d (%+d minutes)\n", setKnown.size(), nTimeOffset, nTimeOffset/60);

    if (nPeersBehind + nPeersAhead < TIMEDATA_WARNING_SAMPLES) {
        if (nTimeOffset < -TIMEDATA_WARNING_THRESHOLD) {
            nPeersBehind++;
        } else if (nTimeOffset > TIMEDATA_WARNING_THRESHOLD) {
            nPeersAhead++;
        }

        if (nPeersBehind + nPeersAhead == TIMEDATA_WARNING_SAMPLES) {
            Warn(nPeersAhead, nPeersBehind);
        }
    }
    return nTimeOffset;
}

void CTimeWarning::Warn(size_t peersAhead, size_t peersBehind)
{
    std::string strMessage;
    if (peersBehind >= TIMEDATA_WARNING_MAJORITY) {
        strMessage = _("Your computer's date and time may be ahead of the rest of the network! If your clock is wrong Zcash will not work properly.");
    } else if (peersAhead >= TIMEDATA_WARNING_MAJORITY) {
        strMessage = _("Your computer's date and time may be behind the rest of the network! If your clock is wrong Zcash will not work properly.");
    } else {
        strMessage = _("Please check that your computer's date and time are correct! If your clock is wrong Zcash will not work properly.");
    }
    SetMiscWarning(strMessage, GetTime());
    uiInterface.ThreadSafeMessageBox(strMessage, "", CClientUIInterface::MSG_WARNING);
}