Method ProcessCompactBlockTxns

src/net_processing.cpp:3472–3557

}

void PeerManagerImpl::ProcessCompactBlockTxns(CNode& pfrom, Peer& peer, const BlockTransactions& block_transactions)
{
    std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
    bool fBlockRead{false};
    {
        LOCK(cs_main);

        auto range_flight = mapBlocksInFlight.equal_range(block_transactions.blockhash);
        size_t already_in_flight = std::distance(range_flight.first, range_flight.second);
        bool requested_block_from_this_peer{false};

        // Multimap ensures ordering of outstanding requests. It's either empty or first in line.
        bool first_in_flight = already_in_flight == 0 || (range_flight.first->second.first == pfrom.GetId());

        while (range_flight.first != range_flight.second) {
            auto [node_id, block_it] = range_flight.first->second;
            if (node_id == pfrom.GetId() && block_it->partialBlock) {
                requested_block_from_this_peer = true;
                break;
            }
            range_flight.first++;
        }

        if (!requested_block_from_this_peer) {
            LogDebug(BCLog::NET, "Peer %d sent us block transactions for block we weren't expecting\n", pfrom.GetId());
            return;
        }

        PartiallyDownloadedBlock& partialBlock = *range_flight.first->second.second->partialBlock;

        if (partialBlock.header.IsNull()) {
            // It is possible for the header to be empty if a previous call to FillBlock wiped the header, but left
            // the PartiallyDownloadedBlock pointer around (i.e. did not call RemoveBlockRequest). In this case, we
            // should not call LookupBlockIndex below.
            RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId());
            Misbehaving(peer, "previous compact block reconstruction attempt failed");
            LogDebug(BCLog::NET, "Peer %d sent compact block transactions multiple times", pfrom.GetId());
            return;
        }

        // We should not have gotten this far in compact block processing unless it's attached to a known header
        const CBlockIndex* prev_block{Assume(m_chainman.m_blockman.LookupBlockIndex(partialBlock.header.hashPrevBlock))};
        ReadStatus status = partialBlock.FillBlock(*pblock, block_transactions.txn,
                                                   /*segwit_active=*/DeploymentActiveAfter(prev_block, m_chainman, Consensus::DEPLOYMENT_SEGWIT));
        if (status == READ_STATUS_INVALID) {
            RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId()); // Reset in-flight state in case Misbehaving does not result in a disconnect
            Misbehaving(peer, "invalid compact block/non-matching block transactions");
            return;
        } else if (status == READ_STATUS_FAILED) {
            if (first_in_flight) {
                // Might have collided, fall back to getdata now :(
                // We keep the failed partialBlock to disallow processing another compact block announcement from the same
                // peer for the same block. We let the full block download below continue under the same m_downloading_since
                // timer.
                std::vector<CInv> invs;
                invs.emplace_back(MSG_BLOCK | GetFetchFlags(peer), block_transactions.blockhash);
                MakeAndPushMessage(pfrom, NetMsgType::GETDATA, invs);
            } else {