Add blocking mechanism for UDP message destinations and enforce for pskreporter addresses

Avoid fragmentation of pskreporter destined datagrams

Keep  datagram size  below  a  reasonable IPv4  MTU  size of  protocol
headers + 1400.

Thanks to Philip,  N1DQ, for the suggestion as with  FT8 mode datagram
payload sizes to Pskrepotrer are sometimes as big a 8kBytes.

Correct a factor of two error in Pskreporter UDP message sizing

Data is built  as a hexadecmal string,  so is twice the  length of the
message bytes it is encoded as.

Merged from trunk.



git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx-1.8@8345 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

MessageClient.cpp

@@ -1,6 +1,8 @@
 #include "MessageClient.hpp"
 
 #include <stdexcept>
+#include <vector>
+#include <algorithm>
 
 #include <QUdpSocket>
 #include <QHostInfo>
@@ -76,6 +78,7 @@ public:
   QHostAddress server_;
   quint32 schema_;
   QTimer * heartbeat_timer_;
+  std::vector<QHostAddress> blocked_addresses_;
 
   // hold messages sent before host lookup completes asynchronously
   QQueue<QByteArray> pending_messages_;
@@ -93,15 +96,24 @@ void MessageClient::impl::host_info_results (QHostInfo host_info)
     }
   else if (host_info.addresses ().size ())
     {
-      server_ = host_info.addresses ()[0];
-
-      // send initial heartbeat which allows schema negotiation
-      heartbeat ();
-
-      // clear any backlog
-      while (pending_messages_.size ())
+      auto server = host_info.addresses ()[0];
+      if (blocked_addresses_.end () == std::find (blocked_addresses_.begin (), blocked_addresses_.end (), server))
         {
-          send_message (pending_messages_.dequeue ());
+          server_ = server;
+
+          // send initial heartbeat which allows schema negotiation
+          heartbeat ();
+
+          // clear any backlog
+          while (pending_messages_.size ())
+            {
+              send_message (pending_messages_.dequeue ());
+            }
+        }
+      else
+        {
+          Q_EMIT self_->error ("UDP server blocked, please try another");
+          pending_messages_.clear (); // discard
         }
     }
 }
@@ -349,6 +361,17 @@ void MessageClient::send_raw_datagram (QByteArray const& message, QHostAddress c
     }
 }
 
+void MessageClient::add_blocked_destination (QHostAddress const& a)
+{
+  m_->blocked_addresses_.push_back (a);
+  if (a == m_->server_)
+    {
+      m_->server_.clear ();
+      Q_EMIT error ("UDP server blocked, please try another");
+      m_->pending_messages_.clear (); // discard
+    }
+}
+
 void MessageClient::status_update (Frequency f, QString const& mode, QString const& dx_call
                                    , QString const& report, QString const& tx_mode
                                    , bool tx_enabled, bool transmitting, bool decoding

MessageClient.hpp

@@ -69,6 +69,10 @@ public:
   // UDP messaging if desired
   Q_SLOT void send_raw_datagram (QByteArray const&, QHostAddress const& dest_address, port_type dest_port);
 
+  // disallowed message destination (does not block datagrams sent
+  // with send_raw_datagram() above)
+  Q_SLOT void add_blocked_destination (QHostAddress const&);
+
   // this signal is emitted if the server sends us a reply, the only
   // reply supported is reply to a prior CQ or QRZ message
   Q_SIGNAL void reply (QTime, qint32 snr, float delta_time, quint32 delta_frequency, QString const& mode

psk_reporter.cpp

@@ -12,6 +12,11 @@
 
 #include "moc_psk_reporter.cpp"
 
+namespace
+{
+  int constexpr MAX_PAYLOAD_LENGTH {1400};
+}
+
 PSK_Reporter::PSK_Reporter(MessageClient * message_client, QObject *parent) :
     QObject {parent},
     m_messageClient {message_client},
@@ -68,10 +73,7 @@ void PSK_Reporter::addRemoteStation(QString call, QString grid, QString freq, QS
 
 void PSK_Reporter::sendReport()
 {
-    if (m_spotQueue.isEmpty()) {
-        return;
-    }
-
+  while (!m_spotQueue.isEmpty()) {
     QString report_h;
 
     // Header
@@ -91,15 +93,16 @@ void PSK_Reporter::sendReport()
 
     // Sender information
     QString txInfoData_h = "50E3llll";
-    while (!m_spotQueue.isEmpty()) {
-        QHash<QString,QString> spot = m_spotQueue.dequeue();
-        txInfoData_h += QString("%1").arg(spot["call"].length(),2,16,QChar('0')) + spot["call"].toUtf8().toHex();
-        txInfoData_h += QString("%1").arg(spot["freq"].toLongLong(),8,16,QChar('0'));
-        txInfoData_h += QString("%1").arg(spot["snr"].toInt(),8,16,QChar('0')).right(2);
-        txInfoData_h += QString("%1").arg(spot["mode"].length(),2,16,QChar('0')) + spot["mode"].toUtf8().toHex();
-        txInfoData_h += QString("%1").arg(spot["grid"].length(),2,16,QChar('0')) + spot["grid"].toUtf8().toHex();
-        txInfoData_h += QString("%1").arg(1,2,16,QChar('0')); // REPORTER_SOURCE_AUTOMATIC
-        txInfoData_h += QString("%1").arg(spot["time"].toInt(),8,16,QChar('0'));
+    while (!m_spotQueue.isEmpty()
+           && (header_h.size () + m_rxInfoDescriptor_h.size () + m_txInfoDescriptor_h.size () + rxInfoData_h.size () + txInfoData_h.size ()) / 2 < MAX_PAYLOAD_LENGTH) {
+      QHash<QString,QString> spot = m_spotQueue.dequeue();
+      txInfoData_h += QString("%1").arg(spot["call"].length(),2,16,QChar('0')) + spot["call"].toUtf8().toHex();
+      txInfoData_h += QString("%1").arg(spot["freq"].toLongLong(),8,16,QChar('0'));
+      txInfoData_h += QString("%1").arg(spot["snr"].toInt(),8,16,QChar('0')).right(2);
+      txInfoData_h += QString("%1").arg(spot["mode"].length(),2,16,QChar('0')) + spot["mode"].toUtf8().toHex();
+      txInfoData_h += QString("%1").arg(spot["grid"].length(),2,16,QChar('0')) + spot["grid"].toUtf8().toHex();
+      txInfoData_h += QString("%1").arg(1,2,16,QChar('0')); // REPORTER_SOURCE_AUTOMATIC
+      txInfoData_h += QString("%1").arg(spot["time"].toInt(),8,16,QChar('0'));
     }
     txInfoData_h += "0000";
     txInfoData_h.replace("50E3llll", "50E3" + QString("%1").arg(txInfoData_h.length()/2,4,16,QChar('0')));
@@ -113,14 +116,18 @@ void PSK_Reporter::sendReport()
     if (!m_pskReporterAddress.isNull()) {
       m_messageClient->send_raw_datagram (report, m_pskReporterAddress, 4739);
     }
+  }
 }
 
 void PSK_Reporter::dnsLookupResult(QHostInfo info)
 {
     if (!info.addresses().isEmpty()) {
         m_pskReporterAddress = info.addresses().at(0);
-//        qDebug() << "PSK Reporter IP: " << m_pskReporterAddress;
+        //        qDebug() << "PSK Reporter IP: " << m_pskReporterAddress;
+
+        // deal with miss-configured settings that attempt to set a
+        // Pskreporter Internet address for the WSJT-X UDP protocol
+        // server address
+        m_messageClient->add_blocked_destination (m_pskReporterAddress);
     }
 }
-
-