Make UDP message handling version mismatch tolerant

By  providing safe  defaults for  expected input  fields that  are not
present in messages from older version  senders, it is now possible to
mix  versions of  clients and  servers.  This  relies on  fields never
changing meaning or content, new fields may be safely added to the end
of existing messages.

Merged from the wsjtx-1.5 branch.



git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@5338 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

MessageClient.cpp

@@ -38,11 +38,13 @@ public:
     closedown ();
   }
 
+  enum StreamStatus {Fail, Short, OK};
+
   void parse_message (QByteArray const& msg);
   void pending_datagrams ();
   void heartbeat ();
   void closedown ();
-  bool check_status (QDataStream const&) const;
+  StreamStatus check_status (QDataStream const&) const;
 
   Q_SLOT void host_info_results (QHostInfo);
 
@@ -91,7 +93,7 @@ void MessageClient::impl::parse_message (QByteArray const& msg)
       // 
       NetworkMessage::Reader in {msg};
 
-      if (id_ == in.id ())          // for us
+      if (OK == check_status (in) && id_ == in.id ()) // OK and for us
         {
           //
           // message format is described in NetworkMessage.hpp
@@ -108,7 +110,7 @@ void MessageClient::impl::parse_message (QByteArray const& msg)
                 QByteArray mode;
                 QByteArray message;
                 in >> time >> snr >> delta_time >> delta_frequency >> mode >> message;
-                if (check_status (in))
+                if (check_status (in) != Fail)
                   {
                     Q_EMIT self_->reply (time, snr, delta_time, delta_frequency
                                          , QString::fromUtf8 (mode), QString::fromUtf8 (message));
@@ -117,23 +119,25 @@ void MessageClient::impl::parse_message (QByteArray const& msg)
               break;
 
             case NetworkMessage::Replay:
-              if (check_status (in))
+              if (check_status (in) != Fail)
                 {
                   Q_EMIT self_->replay ();
                 }
               break;
 
             case NetworkMessage::HaltTx:
-              if (check_status (in))
               {
-                  bool auto_only;
+                bool auto_only {false};
                 in >> auto_only;
+                if (check_status (in) != Fail)
+                  {
                     Q_EMIT self_->halt_tx (auto_only);
                   }
+              }
               break;
 
             case NetworkMessage::FreeText:
-              if (check_status (in))
+              if (check_status (in) != Fail)
                 {
                   QByteArray message;
                   in >> message;
@@ -163,7 +167,7 @@ void MessageClient::impl::heartbeat ()
     {
       QByteArray message;
       NetworkMessage::Builder hb {&message, NetworkMessage::Heartbeat, id_};
-      if (check_status (hb))
+      if (OK == check_status (hb))
         {
           writeDatagram (message, server_, server_port_);
         }
@@ -176,20 +180,22 @@ void MessageClient::impl::closedown ()
     {
       QByteArray message;
       NetworkMessage::Builder out {&message, NetworkMessage::Close, id_};
-      if (check_status (out))
+      if (OK == check_status (out))
         {
           writeDatagram (message, server_, server_port_);
         }
     }
 }
 
-bool MessageClient::impl::check_status (QDataStream const& stream) const
+auto MessageClient::impl::check_status (QDataStream const& stream) const -> StreamStatus
 {
   auto stat = stream.status ();
+  StreamStatus result {Fail};
   switch (stat)
     {
     case QDataStream::ReadPastEnd:
-      Q_EMIT self_->error ("Message serialization error: read failed");
+      qDebug () << __PRETTY_FUNCTION__ << " warning: short UDP message received.";
+      result = Short;
       break;
 
     case QDataStream::ReadCorruptData:
@@ -201,9 +207,10 @@ bool MessageClient::impl::check_status (QDataStream const& stream) const
       break;
 
     default:
+      result = OK;
       break;
     }
-  return QDataStream::Ok == stat;
+  return result;
 }
 
 MessageClient::MessageClient (QString const& id, QString const& server, port_type server_port, QObject * self)
@@ -262,10 +269,14 @@ void MessageClient::status_update (Frequency f, QString const& mode, QString con
       NetworkMessage::Builder out {&message, NetworkMessage::Status, m_->id_};
       out << f << mode.toUtf8 () << dx_call.toUtf8 () << report.toUtf8 () << tx_mode.toUtf8 ()
           << tx_enabled << transmitting;
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, m_->server_, m_->server_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }
 
@@ -277,10 +288,14 @@ void MessageClient::decode (bool is_new, QTime time, qint32 snr, float delta_tim
       QByteArray message;
       NetworkMessage::Builder out {&message, NetworkMessage::Decode, m_->id_};
       out << is_new << time << snr << delta_time << delta_frequency << mode.toUtf8 () << message_text.toUtf8 ();
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, m_->server_, m_->server_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }
 
@@ -290,10 +305,14 @@ void MessageClient::clear_decodes ()
     {
       QByteArray message;
       NetworkMessage::Builder out {&message, NetworkMessage::Clear, m_->id_};
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, m_->server_, m_->server_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }
 
@@ -308,9 +327,13 @@ void MessageClient::qso_logged (QDateTime time, QString const& dx_call, QString
       NetworkMessage::Builder out {&message, NetworkMessage::QSOLogged, m_->id_};
       out << time << dx_call.toUtf8 () << dx_grid.toUtf8 () << dial_frequency << mode.toUtf8 ()
           << report_sent.toUtf8 () << report_received.toUtf8 () << tx_power.toUtf8 () << comments.toUtf8 () << name.toUtf8 ();
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, m_->server_, m_->server_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }

MessageServer.cpp

@@ -34,12 +34,14 @@ public:
     clock_->start (NetworkMessage::pulse * 1000);
   }
 
+  enum StreamStatus {Fail, Short, OK};
+
   void leave_multicast_group ();
   void join_multicast_group ();
   void parse_message (QHostAddress const& sender, port_type sender_port, QByteArray const& msg);
   void tick ();
   void pending_datagrams ();
-  bool check_status (QDataStream const&) const;
+  StreamStatus check_status (QDataStream const&) const;
 
   MessageServer * self_;
   port_type port_;
@@ -110,6 +112,8 @@ void MessageServer::impl::parse_message (QHostAddress const& sender, port_type s
       NetworkMessage::Reader in {msg};
 
       auto id = in.id ();
+      if (OK == check_status (in))
+        {
           bool new_client {false};
           if (!clients_.contains (id))
             {
@@ -142,10 +146,10 @@ void MessageServer::impl::parse_message (QHostAddress const& sender, port_type s
                 QByteArray dx_call;
                 QByteArray report;
                 QByteArray tx_mode;
-            bool tx_enabled;
+                bool tx_enabled {false};
-            bool transmitting;
+                bool transmitting {false};
                 in >> f >> mode >> dx_call >> report >> tx_mode >> tx_enabled >> transmitting;
-            if (check_status (in))
+                if (check_status (in) != Fail)
                   {
                     Q_EMIT self_->status_update (id, f, QString::fromUtf8 (mode), QString::fromUtf8 (dx_call)
                                                  , QString::fromUtf8 (report), QString::fromUtf8 (tx_mode)
@@ -157,7 +161,7 @@ void MessageServer::impl::parse_message (QHostAddress const& sender, port_type s
             case NetworkMessage::Decode:
               {
                 // unpack message
-            bool is_new;
+                bool is_new {true};
                 QTime time;
                 qint32 snr;
                 float delta_time;
@@ -165,7 +169,7 @@ void MessageServer::impl::parse_message (QHostAddress const& sender, port_type s
                 QByteArray mode;
                 QByteArray message;
                 in >> is_new >> time >> snr >> delta_time >> delta_frequency >> mode >> message;
-            if (check_status (in))
+                if (check_status (in) != Fail)
                   {
                     Q_EMIT self_->decode (is_new, id, time, snr, delta_time, delta_frequency
                                           , QString::fromUtf8 (mode), QString::fromUtf8 (message));
@@ -187,7 +191,7 @@ void MessageServer::impl::parse_message (QHostAddress const& sender, port_type s
                 QByteArray name;
                 in >> time >> dx_call >> dx_grid >> dial_frequency >> mode >> report_sent >> report_received
                    >> tx_power >> comments >> name;
-            if (check_status (in))
+                if (check_status (in) != Fail)
                   {
                     Q_EMIT self_->qso_logged (id, time, QString::fromUtf8 (dx_call), QString::fromUtf8 (dx_grid)
                                               , dial_frequency, QString::fromUtf8 (mode), QString::fromUtf8 (report_sent)
@@ -198,7 +202,7 @@ void MessageServer::impl::parse_message (QHostAddress const& sender, port_type s
               break;
 
             case NetworkMessage::Close:
-          if (check_status (in))
+              if (check_status (in) != Fail)
                 {
                   Q_EMIT self_->client_closed (id);
                   clients_.remove (id);
@@ -210,6 +214,11 @@ void MessageServer::impl::parse_message (QHostAddress const& sender, port_type s
               break;
             }
         }
+      else
+        {
+          Q_EMIT self_->error ("MessageServer warning: invalid UDP message received");
+        }
+    }
   catch (std::exception const& e)
     {
       Q_EMIT self_->error (QString {"MessageServer exception: %1"}.arg (e.what ()));
@@ -234,13 +243,15 @@ void MessageServer::impl::tick ()
     }
 }
 
-bool MessageServer::impl::check_status (QDataStream const& stream) const
+auto MessageServer::impl::check_status (QDataStream const& stream) const -> StreamStatus
 {
   auto stat = stream.status ();
+  StreamStatus result {Fail};
   switch (stat)
     {
     case QDataStream::ReadPastEnd:
-      Q_EMIT self_->error ("Message serialization error: read failed");
+      qDebug () << __PRETTY_FUNCTION__ << " warning: short UDP message received.";
+      result = Short;
       break;
 
     case QDataStream::ReadCorruptData:
@@ -252,9 +263,10 @@ bool MessageServer::impl::check_status (QDataStream const& stream) const
       break;
 
     default:
+      result = OK;
       break;
     }
-  return QDataStream::Ok == stat;
+  return result;
 }
 
 MessageServer::MessageServer (QObject * parent)
@@ -296,10 +308,14 @@ void MessageServer::reply (QString const& id, QTime time, qint32 snr, float delt
       QByteArray message;
       NetworkMessage::Builder out {&message, NetworkMessage::Reply, id};
       out << time << snr << delta_time << delta_frequency << mode.toUtf8 () << message_text.toUtf8 ();
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, iter.value ().sender_address_, (*iter).sender_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }
 
@@ -310,10 +326,14 @@ void MessageServer::replay (QString const& id)
     {
       QByteArray message;
       NetworkMessage::Builder out {&message, NetworkMessage::Replay, id};
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, iter.value ().sender_address_, (*iter).sender_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }
 
@@ -325,10 +345,14 @@ void MessageServer::halt_tx (QString const& id, bool auto_only)
       QByteArray message;
       NetworkMessage::Builder out {&message, NetworkMessage::HaltTx, id};
       out << auto_only;
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, iter.value ().sender_address_, (*iter).sender_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }
 
@@ -340,9 +364,13 @@ void MessageServer::free_text (QString const& id, QString const& text)
       QByteArray message;
       NetworkMessage::Builder out {&message, NetworkMessage::FreeText, id};
       out << text.toUtf8 ();
-      if (m_->check_status (out))
+      if (impl::OK == m_->check_status (out))
         {
           m_->writeDatagram (message, iter.value ().sender_address_, (*iter).sender_port_);
         }
+      else
+        {
+          Q_EMIT error ("Error creating UDP message");
+        }
     }
 }