Detect broken GS encapsulation.

.gitignore

@@ -129,3 +129,4 @@ imgui.ini
 /skyscraper8.Manual/skyscraper8.Manual.out
 /skyscraper8.Manual/skyscraper8.Manual.pdf
 /skyscraper8.Manual/skyscraper8.Manual.synctex.gz
+/.vs/skyscraper8/CopilotIndices/17.14.1231.31060

skyscraper8/GSE/BbframeDeencapsulator.cs

@@ -90,6 +90,11 @@ namespace skyscraper8.GSE
 					break;
 				}
 
+				if (!packet.Valid)
+				{
+					break;
+				}
+
 				if (packet.IsCompletePacket)
 				{
 					if (ValidateEthertype(packet.ProtocolType.Value))
@@ -113,6 +118,25 @@ namespace skyscraper8.GSE
 					continue;
 				}
 
+				if (!packet.StartIndicator && packet.EndIndicator)
+				{
+					if (gseFragmentations == null)
+						continue;
+					if (gseFragmentations[packet.FragmentId.Value] == null)
+						continue;
+
+					gseFragmentations[packet.FragmentId.Value].AddPacket(packet);
+					continue;
+				}
+
+				if (!packet.StartIndicator && !packet.EndIndicator)
+				{
+					if (gseFragmentations == null)
+						continue;
+
+					throw new NotImplementedException();
+				}
+
 				throw new NotImplementedException();
 			}
 		}
@@ -129,8 +153,8 @@ namespace skyscraper8.GSE
 
 			long availableBytes = ms.GetAvailableBytes();
 			byte[] readBytes = ms.ReadBytes(availableBytes);
-			
-			GseAssemblyState assemblyState = ValidateGse(gseAssembler);
+
+			GseAssemblyState assemblyState = ValidateGse(gseAssembler, true);
 			if (assemblyState == GseAssemblyState.NOT_YET_BEGUN)
 			{
 				if ((syncByte & 0xc0) == 0xc0)
@@ -195,7 +219,7 @@ namespace skyscraper8.GSE
 			VALID_NULL_PACKET,	//somehow these only show up on TBS6903x, not DD Max SX8?
 		}
 
-		private GseAssemblyState ValidateGse(MemoryStream ms)
+		private GseAssemblyState ValidateGse(MemoryStream ms, bool tryFix = false)
 		{
 			if (ms == null)
 				return GseAssemblyState.NOT_YET_BEGUN;
@@ -204,6 +228,8 @@ namespace skyscraper8.GSE
 			ms.Position = 0;
 			while (ms.GetAvailableBytes() > 2)
 			{
+				long fixPosition = ms.Position;
+
 				//GSE-Header
 				byte byteA = ms.ReadUInt8();
 				bool startIndicator = (byteA & 0x80) != 0;
@@ -224,6 +250,12 @@ namespace skyscraper8.GSE
 					//Console.WriteLine("GSE Length: {0}", gseLength);
 					if (gseLength > 9000)
 					{
+						if (tryFix)
+						{
+							ms.Position = fixPosition;
+							ms.WriteUInt8Repeat(0, (int)ms.GetAvailableBytes());
+							break;
+						}
 						ms.Position = backupPosition;
 						return GseAssemblyState.BROKEN_SUSPECT_LENGTH;
 					}
@@ -236,6 +268,11 @@ namespace skyscraper8.GSE
 
 					if (startIndicator && !endIndicator)
 					{
+						if (2 > ms.GetAvailableBytes())
+						{
+							ms.Position = backupPosition;
+							return GseAssemblyState.NEED_MORE_DATA;
+						}
 						ushort totalLength = ms.ReadUInt16BE();
 						gseLength -= 2;
 					}
@@ -250,6 +287,12 @@ namespace skyscraper8.GSE
 						ushort protocolType = ms.ReadUInt16BE();
 						if (!ValidateEthertype(protocolType))
 						{
+							if (tryFix)
+							{
+								ms.Position = fixPosition;
+								ms.WriteUInt8Repeat(0, (int)ms.GetAvailableBytes());
+								break;
+							}
 							ms.Position = backupPosition;
 							return GseAssemblyState.BROKEN_SUSPECT_ETHERTYPE;
 						}
@@ -278,6 +321,12 @@ namespace skyscraper8.GSE
 
 					if (gseLength < 0)
 					{
+						if (tryFix)
+						{
+							ms.Position = fixPosition;
+							ms.WriteUInt8Repeat(0, (int)ms.GetAvailableBytes());
+							break;
+						}
 						ms.Position = backupPosition;
 						return GseAssemblyState.BROKEN_NEGATIVE_LENGTH;
 					}
@@ -291,6 +340,11 @@ namespace skyscraper8.GSE
 					ms.Position += gseLength;
 					if (!startIndicator && endIndicator)
 					{
+						if (4 > ms.GetAvailableBytes())
+						{
+							ms.Position = backupPosition;
+							return GseAssemblyState.NEED_MORE_DATA;
+						}
 						uint crc32 = ms.ReadUInt32BE();
 						int endCrc32 = (int)ms.Position;
 						DvbCrc32.ValidateCrc(ms, startCrc32, endCrc32);

skyscraper8/GSE/GsePacket.cs

@@ -9,7 +9,7 @@ using skyscraper5.Skyscraper;
 
 namespace skyscraper8.GSE
 {
-	internal class GsePacket
+	internal class GsePacket : Validatable
 	{
 		public static GsePacket Read(MemoryStream ms)
 		{
@@ -62,12 +62,23 @@ namespace skyscraper8.GSE
 				if (!packet.StartIndicator && packet.EndIndicator)
 					gseLength -= 4;
 
+				if (gseLength < 0)
+				{
+					packet.Valid = false;
+					return packet;
+				}
+				if (gseLength > ms.GetAvailableBytes())
+				{
+					packet.Valid = false;
+					return packet;
+				}
 				packet.GseData = ms.ReadBytes(gseLength);
 
 				if (!packet.StartIndicator && packet.EndIndicator)
 					packet.Crc32 = ms.ReadUInt32BE();
 			}
 
+			packet.Valid = true;
 			return packet;
 		}
 

skyscraper8/Mpeg2/TsContext.cs

@@ -1,15 +1,17 @@
-using System;
+using log4net;
+using skyscraper5.Skyscraper;
+using skyscraper5.src.Mpeg2.PacketFilter;
+using System;
 using System.Collections.Generic;
 using System.Net;
 using System.Runtime.CompilerServices;
-using skyscraper5.Skyscraper;
-using skyscraper5.src.Mpeg2.PacketFilter;
 
 namespace skyscraper5.Mpeg2
 {
     public class TsContext : ITsPacketProcessor
     {
-        private ITsPacketProcessor[] processors;
+		private static readonly ILog logger = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType.Name);
+		private ITsPacketProcessor[] processors;
         private uint[] continuities;
         private ulong[] pidPackets;
 
@@ -42,6 +44,8 @@ namespace skyscraper5.Mpeg2
 			if (FilterChain == null || FilterChain.Count == 0)
 				throw new InvalidOperationException("The filter chain has not been initialized.");
 
+			CheckBrokenEncapsulation(packet);
+
 			for (int i = 0; i < FilterChain.Count; i++)
 			{
                 if (FilterChain[i] == null)
@@ -61,6 +65,44 @@ namespace skyscraper5.Mpeg2
             processors[packet.PID].PushPacket(packet);
         }
 
+        private bool encapsulationBrokenConfirmed;
+        private bool CheckBrokenEncapsulation(TsPacket packet)
+        {
+	        if (encapsulationBrokenConfirmed)
+		        return true;
+
+	        switch (packet.PID)
+	        {
+                case 0x0000:
+                case 0x0001:
+	                break;
+                default:
+	                return false;
+	        }
+
+	        int occupiedPids = CountOccupiedPids();
+	        if (occupiedPids < 1000)
+		        return false;
+
+	        if (packet.TSC == 0)
+		        return false;
+
+            logger.WarnFormat("It looks like you're either having bad reception or this is a GS with broken encapsulation. This means that you either have FrameMode enabled, or are not using a STiD135.");
+            encapsulationBrokenConfirmed = true;
+            return true;
+        }
+
+        private int CountOccupiedPids()
+        {
+	        int result = 0;
+	        for (int i = 0; i < pidPackets.Length; i++)
+	        {
+		        if (pidPackets[i] > 0)
+			        result++;
+	        }
+	        return result;
+        }
+
         private bool EnsureContinuity(TsPacket packet)
         {
             //Found in ISO 13818-1.pdf, page 38

skyscraper8/Properties/launchSettings.json

@@ -2,7 +2,7 @@
   "profiles": {
     "skyscraper8": {
       "commandName": "Project",
-      "commandLineArgs": "\"\\\\utena\\mergerfs\\Skyscraper\\ipProto253_eutelsat7_10803h-max-sx8.ts\"",
+      "commandLineArgs": "cscan tcp://172.20.20.203:6969",
       "remoteDebugEnabled": false
     },
     "Container (Dockerfile)": {