ExploreResponse: Objects are a list of objects, not a single one.

thomas-v2 · thomas-v2 · commit 8ea8087c0fbf · 2023-12-25T13:40:40.000+01:00
Before if it was a list of objects, the first was used as parent object,
which was wrong. As a result if a list of objects was in the response
(without a parent object), the first object was not processed correct
(as a result, exploring the list of DBs, the first DB was missing.
The change thus affects all other parts which use the explore function.
diff --git a/src/S7CommPlusDriver/Alarming/BrowseAlarms.cs b/src/S7CommPlusDriver/Alarming/BrowseAlarms.cs
@@ -17,6 +17,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 
 namespace S7CommPlusDriver
 {
@@ -66,10 +67,13 @@ public int ExploreASAlarms(ref Dictionary<ulong, AlarmData> Alarms, int language
             {
                 return res;
             }
-            List<PObject> staiclass = exploreRes.ResponseObject.GetObjectsByClassId(Ids.MultipleSTAI_Class_Rid);
-            if (staiclass != null && staiclass.Count > 0)
+
+            var alarmobjs = exploreRes.Objects.First(o => o.RelationId == 0x8a7e0000).GetObjects();
+            var staiclass = alarmobjs.First(o => o.ClassId == Ids.MultipleSTAI_Class_Rid);
+
+            if (staiclass != null)
             {
-                PValue stais = staiclass[0].GetAttribute(Ids.MultipleSTAI_STAIs);
+                PValue stais = staiclass.GetAttribute(Ids.MultipleSTAI_STAIs);
                 if (stais != null)
                 {
                     if (stais.GetType() == typeof(ValueBlobSparseArray))
@@ -133,14 +137,14 @@ public int ExploreASAlarms(ref Dictionary<ulong, AlarmData> Alarms, int language
             }
 
             // All objects which have Alarm AP inside, have a sub-Object with ID 7854 = MultipleSTAI.Class_Rid
-            List<PObject> objList = exploreRes.ResponseObject.GetObjects();
+            var obj = exploreRes.Objects.First(o => o.ClassId == Ids.PLCProgram_Class_Rid);
 
-            foreach (var ob in objList)
+            foreach (var ob in obj.GetObjects())
             {
-                staiclass = ob.GetObjectsByClassId(Ids.MultipleSTAI_Class_Rid);
-                if (staiclass != null && staiclass.Count > 0)
+                var staiclasses = ob.GetObjectsByClassId(Ids.MultipleSTAI_Class_Rid);
+                if (staiclasses != null && staiclasses.Count > 0)
                 {
-                    PValue stais = staiclass[0].GetAttribute(Ids.MultipleSTAI_STAIs);
+                    PValue stais = staiclasses[0].GetAttribute(Ids.MultipleSTAI_STAIs);
                     if (stais != null)
                     {
                         if (stais.GetType() == typeof(ValueBlobSparseArray))
@@ -200,9 +204,11 @@ public int ExploreASAlarms(ref Dictionary<ulong, AlarmData> Alarms, int language
             // [0] contains informations of how to get infos from [1], which has infos about offsets in [2].
             // [2] contains the resulting offsets for the strings in TextLibraryStringArea.
             // TODO: Check if all fields are present, or use try/catch?
-
-            var tloa = ((ValueBlobArray)exploreRes.ResponseObject.GetAttribute(Ids.TextLibraryOffsetArea)).GetValue();
-            var tlsa = ((ValueBlob)exploreRes.ResponseObject.GetAttribute(Ids.TextLibraryStringArea)).GetValue();
+            ValueBlob[] tloa = null;
+            byte[] tlsa = null;
+            var textlib = exploreRes.Objects.First(o => o.ClassId == Ids.TextLibraryClassRID);
+            tloa = ((ValueBlobArray)textlib.GetAttribute(Ids.TextLibraryOffsetArea)).GetValue();
+            tlsa = ((ValueBlob)textlib.GetAttribute(Ids.TextLibraryStringArea)).GetValue();
 
             var tloa_1 = tloa[0].GetValue();
             var tloa_2 = tloa[1].GetValue();
diff --git a/src/S7CommPlusDriver/Core/ExploreResponse.cs b/src/S7CommPlusDriver/Core/ExploreResponse.cs
@@ -15,6 +15,7 @@
 
 using System;
 using System.IO;
+using System.Collections.Generic;
 
 namespace S7CommPlusDriver
 {
@@ -23,7 +24,7 @@ public class ExploreResponse : IS7pResponse
         public byte TransportFlags;
         public UInt64 ReturnValue;
         public UInt32 ExploreId;
-        public PObject ResponseObject;
+        public List<PObject> Objects;
 
         public byte ProtocolVersion { get; set; }
         public ushort FunctionCode { get => Functioncode.Explore; }
@@ -53,8 +54,10 @@ public int Deserialize(Stream buffer)
                 ret += S7p.DecodeUInt32Vlq(buffer, out uint iid);
                 IntegrityId = iid;
             }
-            // See comment in Wireshark dissector code
-            ret += S7p.DecodeObject(buffer, ref ResponseObject);
+
+            // This is a List of objects
+            Objects = new List<PObject>();
+            ret += S7p.DecodeObjectList(buffer, ref Objects);
             return ret;
         }
 
@@ -68,7 +71,12 @@ public override string ToString()
             s += "<ResponseSet>" + Environment.NewLine;
             s += "<ReturnValue>" + ReturnValue.ToString() + "</ReturnValue>" + Environment.NewLine;
             s += "<ExploreId>" + ExploreId.ToString() + "</ExploreId>" + Environment.NewLine;
-            s += "<ResponseObject>" + ResponseObject.ToString() + "</ResponseObject>" + Environment.NewLine;
+            s += "<Objects>";
+            foreach (var obj in Objects)
+            {
+                s += obj.ToString();
+            }
+            s += "</Objects>" + Environment.NewLine;
             s += "</ResponseSet>" + Environment.NewLine;
             s += "</ExploreResponse>" + Environment.NewLine;
             return s;
diff --git a/src/S7CommPlusDriver/Core/Ids.cs b/src/S7CommPlusDriver/Core/Ids.cs
@@ -37,7 +37,9 @@ public static class Ids
         public const int ServerSessionClientRID = 300;
         public const int ServerSessionVersion = 306;
         public const int ClassTypeInfo = 511;
+        public const int ClassOMSTypeInfoContainer = 534;
         public const int ObjectOMSTypeInfoContainer = 537;
+        public const int TextLibraryClassRID = 606;
         public const int TextLibraryOffsetArea = 608;
         public const int TextLibraryStringArea = 609;
         public const int SystemLimits = 1037;
@@ -51,6 +53,7 @@ public static class Ids
         public const int CompositionAID = 1258;
         public const int KeyQualifier = 1259;
         public const int CPUexecUnit_operatingStateReq = 2167;
+        public const int PLCProgram_Class_Rid = 2520;
         public const int Block_BlockNumber = 2521;
         public const int DB_ValueInitial = 2548;
         public const int DB_ValueActual = 2550;
diff --git a/src/S7CommPlusDriver/Core/S7p.cs b/src/S7CommPlusDriver/Core/S7p.cs
@@ -15,6 +15,7 @@
 
 using System;
 using System.Text;
+using System.Collections.Generic;
 
 namespace S7CommPlusDriver
 {
@@ -634,7 +635,26 @@ public static int DecodeOctets(System.IO.Stream buffer, int length, out byte[] v
         ///////////////////////////////////////////////////////////////////////////////////////
         // High Level Decode/Encode methods
 
-        public static int DecodeObject(System.IO.Stream buffer, ref PObject obj)
+        public static int DecodeObjectList(System.IO.Stream buffer, ref List<PObject> objList)
+        {
+            int ret = 0;
+            byte tagId;
+            objList = new List<PObject>();
+            // Peek one byte and set buffer back
+            S7p.DecodeByte(buffer, out tagId);
+            buffer.Position -= 1;
+            while (tagId == ElementID.StartOfObject)
+            {
+                PObject obj = null;
+                ret += S7p.DecodeObject(buffer, ref obj, AsList: true);
+                objList.Add(obj);
+                S7p.DecodeByte(buffer, out tagId);
+                buffer.Position -= 1;
+            }
+            return ret;
+        }
+
+        public static int DecodeObject(System.IO.Stream buffer, ref PObject obj, bool AsList = false)
         {
             byte tagId;
             UInt32 id;
@@ -653,7 +673,12 @@ public static int DecodeObject(System.IO.Stream buffer, ref PObject obj)
                             ret += DecodeUInt32Vlq(buffer, out obj.ClassId);
                             ret += DecodeUInt32Vlq(buffer, out obj.ClassFlags);
                             ret += DecodeUInt32Vlq(buffer, out obj.AttributeId);
-                            ret += DecodeObject(buffer, ref obj);
+                            // If a List is expected, don't add the objects coming next to the parent object
+                            // TODO: May be it's better to always expect a list? Adding the following objects to the first as children must always be wrong.
+                            if (AsList == false)
+                            {
+                                ret += DecodeObject(buffer, ref obj);
+                            }
                         }
                         else
                         {
diff --git a/src/S7CommPlusDriver/S7CommPlusConnection.cs b/src/S7CommPlusDriver/S7CommPlusConnection.cs
@@ -18,6 +18,7 @@
 using System.Text;
 using System.Threading;
 using System.IO;
+using System.Linq;
 
 namespace S7CommPlusDriver
 {
@@ -717,9 +718,9 @@ public int Browse(out List<VarInfo> varInfoList)
 
             #region Evaluate all data blocks that then need to be browsed
 
-            List<PObject> objList = exploreRes.ResponseObject.GetObjects();
+            var obj = exploreRes.Objects.First(o => o.ClassId == Ids.PLCProgram_Class_Rid);
 
-            foreach (var ob in objList)
+            foreach (var ob in obj.GetObjects())
             {
                 switch (ob.ClassId)
                 {
@@ -836,9 +837,9 @@ public int Browse(out List<VarInfo> varInfoList)
             {
                 return res;
             }
-            List<PObject> objs = exploreResponse.ResponseObject.GetObjectsByClassId(Ids.ClassTypeInfo);
+            var objs = exploreResponse.Objects.First(o => o.ClassId == Ids.ClassOMSTypeInfoContainer);
 
-            vars.SetTypeInfoContainerObjects(objs);
+            vars.SetTypeInfoContainerObjects(objs.GetObjects());
             vars.BuildTree();
             vars.BuildFlatList();
             varInfoList = vars.GetVarInfoList();
@@ -919,7 +920,7 @@ public int GetListOfDatablocks(out List<DatablockInfo> dbInfoList)
             }
 
             // Get the datablock information we want further informations from.
-            var objList = exploreRes.ResponseObject.GetObjects();
+            var objList = exploreRes.Objects;
 
             foreach (var ob in objList)
             {
@@ -1027,7 +1028,7 @@ public int GetTypeInformation(uint exploreId, out List<PObject> objList)
             {
                 return res;
             }
-            objList.Add(exploreRes.ResponseObject);
+            objList = exploreRes.Objects;
 
             return 0;
         }

Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,7 @@`
`18`	`18`	`using System.Text;`
`19`	`19`	`using System.Threading;`
`20`	`20`	`using System.IO;`
	`21`	`+using System.Linq;`
`21`	`22`
`22`	`23`	`namespace S7CommPlusDriver`
`23`	`24`	`{`
`@@ -717,9 +718,9 @@ public int Browse(out List<VarInfo> varInfoList)`
`717`	`718`
`718`	`719`	`#region Evaluate all data blocks that then need to be browsed`
`719`	`720`
`720`		`- List<PObject> objList = exploreRes.ResponseObject.GetObjects();`
	`721`	`+ var obj = exploreRes.Objects.First(o => o.ClassId == Ids.PLCProgram_Class_Rid);`
`721`	`722`
`722`		`- foreach (var ob in objList)`
	`723`	`+ foreach (var ob in obj.GetObjects())`
`723`	`724`	`{`
`724`	`725`	`switch (ob.ClassId)`
`725`	`726`	`{`
`@@ -836,9 +837,9 @@ public int Browse(out List<VarInfo> varInfoList)`
`836`	`837`	`{`
`837`	`838`	`return res;`
`838`	`839`	`}`
`839`		`- List<PObject> objs = exploreResponse.ResponseObject.GetObjectsByClassId(Ids.ClassTypeInfo);`
	`840`	`+ var objs = exploreResponse.Objects.First(o => o.ClassId == Ids.ClassOMSTypeInfoContainer);`
`840`	`841`
`841`		`- vars.SetTypeInfoContainerObjects(objs);`
	`842`	`+ vars.SetTypeInfoContainerObjects(objs.GetObjects());`
`842`	`843`	`vars.BuildTree();`
`843`	`844`	`vars.BuildFlatList();`
`844`	`845`	`varInfoList = vars.GetVarInfoList();`
`@@ -919,7 +920,7 @@ public int GetListOfDatablocks(out List<DatablockInfo> dbInfoList)`
`919`	`920`	`}`
`920`	`921`
`921`	`922`	`// Get the datablock information we want further informations from.`
`922`		`- var objList = exploreRes.ResponseObject.GetObjects();`
	`923`	`+ var objList = exploreRes.Objects;`
`923`	`924`
`924`	`925`	`foreach (var ob in objList)`
`925`	`926`	`{`
`@@ -1027,7 +1028,7 @@ public int GetTypeInformation(uint exploreId, out List<PObject> objList)`
`1027`	`1028`	`{`
`1028`	`1029`	`return res;`
`1029`	`1030`	`}`
`1030`		`- objList.Add(exploreRes.ResponseObject);`
	`1031`	`+ objList = exploreRes.Objects;`
`1031`	`1032`
`1032`	`1033`	`return 0;`
`1033`	`1034`	`}`