Implement override checksum for GRE

common/gre.cpp

@@ -89,8 +89,16 @@ AbstractProtocol::FieldFlags GreProtocol::fieldFlags(int index) const
 
     flags = AbstractProtocol::fieldFlags(index);
 
-    if (index == gre_checksum)
+    switch (index) {
+    case gre_checksum:
         flags |= CksumField;
+        break;
+
+    case gre_isOverrideChecksum:
+        flags &= ~FrameField;
+        flags |= MetaField;
+        break;
+    }
 
     return flags;
 }
@@ -218,18 +226,21 @@ QVariant GreProtocol::fieldData(int index, FieldAttrib attrib,
             if (attrib == FieldBitSize)
                 return 16;
 
-            quint32 sum = 0;
             quint16 cksum;
+            if (data.is_override_checksum()) {
+                cksum = data.checksum();
+            } else {
+                quint32 sum = 0;
+                cksum = protocolFrameCksum(streamIndex, CksumIp);
+                sum += (quint16) ~cksum;
+                cksum = protocolFramePayloadCksum(streamIndex, CksumIp);
+                sum += (quint16) ~cksum;
 
-            cksum = protocolFrameCksum(streamIndex, CksumIp);
-            sum += (quint16) ~cksum;
-            cksum = protocolFramePayloadCksum(streamIndex, CksumIp);
-            sum += (quint16) ~cksum;
+                while (sum >> 16)
+                    sum = (sum & 0xFFFF) + (sum >> 16);
 
-            while (sum >> 16)
-                sum = (sum & 0xFFFF) + (sum >> 16);
-
-            cksum = (~sum) & 0xFFFF;
+                cksum = (~sum) & 0xFFFF;
+            }
 
             switch(attrib)
             {
@@ -347,6 +358,19 @@ QVariant GreProtocol::fieldData(int index, FieldAttrib attrib,
             break;
         }
 
+        // Meta fields
+        case gre_isOverrideChecksum:
+        {
+            switch(attrib)
+            {
+                case FieldValue:
+                    return data.is_override_checksum();
+                default:
+                    break;
+            }
+            break;
+        }
+
         default:
             qFatal("%s: unimplemented case %d in switch", __PRETTY_FUNCTION__,
                 index);
@@ -406,6 +430,11 @@ bool GreProtocol::setFieldData(int index, const QVariant &value,
                 data.set_checksum(csum);
             break;
         }
+        case gre_isOverrideChecksum:
+        {
+            data.set_is_override_checksum(value.toBool());
+            break;
+        }
         case gre_rsvd1:
         {
             uint rsvd1 = value.toUInt(&isOk);

common/gre.h

@@ -58,6 +58,9 @@ public:
         gre_key,
         gre_sequence,
 
+        // Meta Fields
+        gre_isOverrideChecksum,
+
         gre_fieldCount
     };
 

common/gre.proto

@@ -28,9 +28,10 @@ message Gre {
     optional uint32    version = 3;
     optional uint32    protocol_type = 4;
     optional uint32    checksum = 5;
-    optional uint32    rsvd1 = 6;
-    optional uint32    key = 7 [default = 0x2020bad7];
-    optional uint32    sequence_num = 8;
+    optional bool      is_override_checksum = 6;
+    optional uint32    rsvd1 = 7;
+    optional uint32    key = 8 [default = 0x2020bad7];
+    optional uint32    sequence_num = 9;
 }
 
 extend Protocol {

common/gre.ui

@@ -62,9 +62,15 @@
      <property name="prefix">
       <string>0x</string>
      </property>
+     <property name="minimum">
+      <number>-1</number>
+     </property>
      <property name="maximum">
       <number>65535</number>
      </property>
+     <property name="value">
+      <number>-1</number>
+     </property>
      <property name="displayIntegerBase">
       <number>16</number>
      </property>
@@ -167,5 +173,21 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>hasChecksum</sender>
+   <signal>toggled(bool)</signal>
+   <receiver>checksum</receiver>
+   <slot>setEnabled(bool)</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>87</x>
+     <y>43</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>109</x>
+     <y>45</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
 </ui>

common/greconfig.cpp

@@ -24,6 +24,9 @@ GreConfigForm::GreConfigForm(QWidget *parent)
     : AbstractProtocolConfigForm(parent)
 {
     setupUi(this);
+
+    connect(hasChecksum, SIGNAL(clicked(bool)),
+            this, SLOT(setAutoChecksum(bool)));
 }
 
 GreConfigForm::~GreConfigForm()
@@ -51,9 +54,11 @@ void GreConfigForm::loadWidget(AbstractProtocol *proto)
     hasChecksum->setChecked(flags & GRE_FLAG_CKSUM);
     checksum->setValue(
         proto->fieldData(
-            GreProtocol::gre_checksum,
-            AbstractProtocol::FieldValue
-        ).toUInt());
+            GreProtocol::gre_isOverrideChecksum,
+            AbstractProtocol::FieldValue).toBool() ?
+            proto->fieldData(
+                GreProtocol::gre_checksum,
+                AbstractProtocol::FieldValue).toUInt() : -1);
 
     hasKey->setChecked(flags & GRE_FLAG_KEY);
     key->setValue(
@@ -93,6 +98,9 @@ void GreConfigForm::storeWidget(AbstractProtocol *proto)
     proto->setFieldData(
         GreProtocol::gre_checksum,
         checksum->value());
+    proto->setFieldData(
+        GreProtocol::gre_isOverrideChecksum,
+        checksum->value() > -1 ? true: false);
 
     proto->setFieldData(
         GreProtocol::gre_key,
@@ -103,3 +111,8 @@ void GreConfigForm::storeWidget(AbstractProtocol *proto)
         sequence->value());
 }
 
+void GreConfigForm::setAutoChecksum(bool enabled)
+{
+    if (enabled)
+        checksum->setValue(-1); // auto
+}

common/greconfig.h

@@ -36,6 +36,9 @@ public:
 
     virtual void loadWidget(AbstractProtocol *proto);
     virtual void storeWidget(AbstractProtocol *proto);
+
+private slots:
+    void setAutoChecksum(bool enabled);
 };
 
 #endif

common/grepdml.cpp

@@ -91,9 +91,14 @@ void PdmlGreProtocol::prematureEndHandler(int /*pos*/,
  Ostinato recalculate these, you can set the is_override_length,
  is_override_cksum meta-fields to true here
 */
-void PdmlGreProtocol::postProtocolHandler(OstProto::Protocol* /*pbProto*/,
+void PdmlGreProtocol::postProtocolHandler(OstProto::Protocol* pbProto,
         OstProto::Stream* /*stream*/)
 {
+    OstProto::Gre *gre = pbProto->MutableExtension(OstProto::gre);
+
+    qDebug("GRE: post");
+
+    gre->set_is_override_checksum(overrideCksum_);
     return;
 }