Method PushMessage

src/net.cpp:4140–4198

}

void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg)
{
    AssertLockNotHeld(m_total_bytes_sent_mutex);

    if (pnode->IsPrivateBroadcastConn() && !IsOutboundMessageAllowedInPrivateBroadcast(msg.m_type)) {
        LogDebug(BCLog::PRIVBROADCAST, "Omitting send of message '%s', %s", msg.m_type, pnode->LogPeer());
        return;
    }

    if (!m_private_broadcast.m_outbound_tor_ok_at_least_once.load() && !pnode->IsInboundConn() &&
        pnode->addr.IsTor() && msg.m_type == NetMsgType::VERACK) {
        // If we are sending the peer VERACK that means we successfully sent
        // and received another message to/from that peer (VERSION).
        m_private_broadcast.m_outbound_tor_ok_at_least_once.store(true);
    }

    size_t nMessageSize = msg.data.size();
    LogDebug(BCLog::NET, "sending %s (%d bytes) peer=%d\n", msg.m_type, nMessageSize, pnode->GetId());
    if (m_capture_messages) {
        CaptureMessage(pnode->addr, msg.m_type, msg.data, /*is_incoming=*/false);
    }

    TRACEPOINT(net, outbound_message,
        pnode->GetId(),
        pnode->m_addr_name.c_str(),
        pnode->ConnectionTypeAsString().c_str(),
        msg.m_type.c_str(),
        msg.data.size(),
        msg.data.data()
    );

    size_t nBytesSent = 0;
    {
        LOCK(pnode->cs_vSend);
        // Check if the transport still has unsent bytes, and indicate to it that we're about to
        // give it a message to send.
        const auto& [to_send, more, _msg_type] =
            pnode->m_transport->GetBytesToSend(/*have_next_message=*/true);
        const bool queue_was_empty{to_send.empty() && pnode->vSendMsg.empty()};

        // Update memory usage of send buffer.
        pnode->m_send_memusage += msg.GetMemoryUsage();
        if (pnode->m_send_memusage + pnode->m_transport->GetSendMemoryUsage() > nSendBufferMaxSize) pnode->fPauseSend = true;
        // Move message to vSendMsg queue.
        pnode->vSendMsg.push_back(std::move(msg));

        // If there was nothing to send before, and there is now (predicted by the "more" value
        // returned by the GetBytesToSend call above), attempt "optimistic write":
        // because the poll/select loop may pause for SELECT_TIMEOUT_MILLISECONDS before actually
        // doing a send, try sending from the calling thread if the queue was empty before.
        // With a V1Transport, more will always be true here, because adding a message always
        // results in sendable bytes there, but with V2Transport this is not the case (it may
        // still be in the handshake).
        if (queue_was_empty && more) {
            std::tie(nBytesSent, std::ignore) = SocketSendData(*pnode);
        }
    }
    if (nBytesSent) RecordBytesSent(nBytesSent);