EllanJiang/GameFramework · error · GameFrameworkException

Target length is invalid.

Error message

Target length is invalid.

What it means

ReceiveState.Reset sizes the internal receive stream to the incoming packet's length; a negative targetLength is invalid and throws GameFrameworkException. Called from PrepareForPacketHeader and PrepareForPacket, so a header reporting a negative packet length triggers it.

Solutions

1. Fix the header deserialization so PacketLength is read with the correct endianness and width used by the server.
2. Validate PacketLength >= 0 (and <= a sane maximum) in your DeserializePacketHeader and fail the header step there.
3. Check for signed/unsigned conversion bugs on the length field (use uint/long parsing where the protocol is unsigned).

Example fix

// before
int length = reader.ReadInt16(); // wrong width/endianness
// after
int length = (int)BinaryPrimitives.ReadUInt32BigEndian(buffer); // matches server header layout

public static bool IsValidHeader(IPacketHeader h) => h != null && h.PacketLength >= 0 && h.PacketLength <= MaxPacketSize;

public static bool HasValidLength(IPacketHeader h) => h is { PacketLength: >= 0 };

try { PrepareReceive(header); } catch (GameFrameworkException ex) when (ex.Message == "Target length is invalid.") { CloseAndReconnect(channel); }

When it happens

Trigger: A deserialized IPacketHeader whose PacketLength is negative (corrupted header data, wrong endianness when reading the length field, signed overflow); custom headers computing length incorrectly.

Common situations: Header length field parsed with wrong byte order producing huge/negative values; protocol mismatch where a payload byte is interpreted as part of the length; int overflow when the length field is unsigned in the protocol but signed in C#.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• Packet header is invalid.
• You must connect first.
• Socket is not active.
• Packet is invalid.
• Serialized packet failure.

AI-assisted analysis of EllanJiang/GameFramework@d0c010b051 (2026-09-15). Data as JSON: /api/errors/1f5c249e2decaada. Report an issue: GitHub.

Appendix: source

Thrown at GameFramework/Network/NetworkManager.ReceiveState.cs:89

                }

                if (disposing)
                {
                    if (m_Stream != null)
                    {
                        m_Stream.Dispose();
                        m_Stream = null;
                    }
                }

                m_Disposed = true;
            }

            private void Reset(int targetLength, IPacketHeader packetHeader)
            {
                if (targetLength < 0)
                {
                    throw new GameFrameworkException("Target length is invalid.");
                }

                m_Stream.Position = 0L;
                m_Stream.SetLength(targetLength);
                m_PacketHeader = packetHeader;
            }
        }
    }
}

View on GitHub (pinned to d0c010b051)