Fixed object header issues and "trying to read past the buffer size" errors caused by NetEntityEvents for removed entities.

EntityEventManager sends an empty event with an ID of 0 if the entity doesn't exist anymore when writing the event. The recipient should simply skip over these messages and read the next one, but clients only did so if the event is the next unreceived one, causing the rest of the messages to be read incorrectly (which could lead to various sorts of problems in addition to the header and buffer size errors). The server didn't deal with the empty events correctly either, it increased the last received ID even if the received event was not the one the server is waiting for, potentially causing other non-empty events to be ignored.

+ Added an error message if the size of an NetEntityEvent is larger than 255 bytes. Not only is that excessively large for an event, but the length of the event is written as a byte and larger ones may again cause messages to be read incorrectly. Most events should be nowhere near 255 bytes, but now that the descriptions and tags of a spawned item are included in the item spawn messages there's the possibility that some events are too large.

Barotrauma/BarotraumaClient/Source/Networking/NetEntityEvent/ClientEntityEventManager.cs

@@ -132,21 +132,21 @@ namespace Barotrauma.Networking
 
             UInt16 firstEventID = msg.ReadUInt16();
             int eventCount = msg.ReadByte();
-
+            
             for (int i = 0; i < eventCount; i++)
             {
-                UInt16 thisEventID = (UInt16)(firstEventID + (UInt16)i);
+                UInt16 thisEventID = (UInt16)(firstEventID + (UInt16)i);                
                 UInt16 entityID = msg.ReadUInt16();
                 
-                if (entityID == 0 && thisEventID == (UInt16)(lastReceivedID + 1))
+                if (entityID == 0)
                 {
                     msg.ReadPadBits();
-                    lastReceivedID++;
+                    if (thisEventID == (UInt16)(lastReceivedID + 1)) lastReceivedID++;
                     continue;
                 }
 
                 byte msgLength = msg.ReadByte();
-
+                
                 IServerSerializable entity = Entity.FindEntityByID(entityID) as IServerSerializable;
                 entities.Add(entity);
 

Barotrauma/BarotraumaShared/Source/Networking/NetEntityEvent/NetEntityEventManager.cs

@@ -45,7 +45,12 @@ namespace Barotrauma.Networking
                     //no more room in this packet
                     break;
                 }
-                
+
+                if (tempEventBuffer.LengthBytes > 255)
+                {
+                    DebugConsole.ThrowError("Too much data in network event for entity \"" + e.Entity.ToString() + "\" (" + tempEventBuffer.LengthBytes + " bytes");
+                }
+
                 //the ID has been taken by another entity (the original entity has been removed) -> write an empty event
                 if (Entity.FindEntityByID(e.Entity.ID) != e.Entity)
                 {

Barotrauma/BarotraumaShared/Source/Networking/NetEntityEvent/ServerEntityEventManager.cs

@@ -326,7 +326,7 @@ namespace Barotrauma.Networking
                 if (entityID == 0)
                 {
                     msg.ReadPadBits();
-                    sender.LastSentEntityEventID++;
+                    if (thisEventID == (UInt16)(sender.LastSentEntityEventID + 1)) sender.LastSentEntityEventID++;
                     continue;
                 }