Function ProcessGetHeadersMessage

src/p2p/chainmessage.cpp:512–552

}

bool ProcessGetHeadersMessage(CNode *pFrom, CDataStream &vRecv) {
    CBlockLocator locator;
    uint256 hashStop;
    vRecv >> locator >> hashStop;

    LOCK(cs_main);

    CBlockIndex *pIndex = nullptr;
    if (locator.IsNull()) {
        // If locator is null, return the hashStop block
        map<uint256, CBlockIndex *>::iterator mi = mapBlockIndex.find(hashStop);
        if (mi == mapBlockIndex.end())
            return true;

        pIndex = (*mi).second;
    } else {
        // Find the last block the caller has in the main chain
        pIndex = chainActive.FindFork(mapBlockIndex, locator);
        if (pIndex)
            pIndex = chainActive.Next(pIndex);
    }

    // We must use CBlocks, as CBlockHeaders won't include the 0x00 nTx count at the end
    vector<CBlock> vHeaders;
    int32_t nLimit = 2000;
    LogPrint(BCLog::NET, "getheaders %d to %s from peer %s\n", (pIndex ? pIndex->height : -1), hashStop.ToString(),
             pFrom->addr.ToString());

    for (; pIndex; pIndex = chainActive.Next(pIndex)) {
        CBlockHeader blockHeader;
        if (!GetBlockHeader(pIndex, blockHeader))
            return ERRORMSG("get block=%s index failed", pIndex->GetIdString());
        vHeaders.push_back(blockHeader);

        if (--nLimit <= 0 || pIndex->GetBlockHash() == hashStop)
            break;
    }
    pFrom->PushMessage("headers", vHeaders);

    return false;
}

void ProcessGetBlocksMessage(CNode *pFrom, CDataStream &vRecv) {
    CBlockLocator locator;