### Summary
- Bump IORingGroup 1.0.0 → 1.0.1 — fixes a disconnect handling bug in the native ring layer
- Fix ghost NetStates — Dispose() set _running = false before checking it, so the "force immediate disconnect" path
was dead code. Capture wasRunning before clearing it, add [Obsolete] guard, and route internal callers through
DisposeInternal()
- Fix unauthenticated socket cleanup — graceful disconnect on unauthed connections could get stuck with pending sends;
now force-immediate after Disconnect() if DisconnectPending is already set
- Replace ConcurrentQueue<NetState> _disposed with Queue<NetState> — server is single-threaded; moved the field into
the Network partial class where it's consumed
- Move ConnectingSocketIdleLimit into the Network partial class alongside DisconnectUnattachedSockets
- Reset activity timer on receive, not just send — receiving data directly proves liveness instead of relying on the
ping→pong→send round-trip to reset the timer
- Move CheckAllAlive from Timer into Slice — the timer fired before I/O completions were processed, so after server
stalls (world saves), buffered client pings hadn't reset timestamps yet, causing false disconnects. Now runs at the
end of Slice() after all recv completions are handled
- Lower inactivity timeout 90s → 30s, check interval 90s → 5s — clients ping every ~1s, so 30s of silence is ~30
missed pings; worst-case detection drops from ~180s to ~35s
- Simplify CheckAlive — early-return when socket is null or alive; force-kill stuck DisconnectPending sockets
immediately instead of calling Disconnect() again
- Remove unused imports from GameEncryption.cs
> [!IMPORTANT]
> **Breaking Changes**
> - DecodePacket and EncodePacket delegates replaced with IClientEncryption interface
> - NetState.Connection (Socket) replaced with internal RingSocket management
> - NetState.RecvPipe and NetState.SendPipe removed (buffers managed internally)
## Summary
Upgrades the networking stack from PollGroup-based I/O to io_uring, significantly improving I/O performance on Linux.
This also adds native client encryption support for encrypted UO clients.
## Major Changes
io_uring Networking Architecture
- Replaced PollGroup with IORingGroup for async socket I/O operations
- Removed Pipe.cs (mirrored ring buffer) and TcpServer.cs in favor of RingSocketManager
- Added NetState.Network.cs - centralized network infrastructure handling accept, recv, send, and disconnect
completions
- Added SocketHelper.cs - platform-specific socket utilities for raw socket handle operations (getpeername,
getsockname)
- Buffer management now handled by RingSocketManager with configurable slab allocation
### Client Encryption Support
- Added full encryption stack in Network/Encryption/:
- EncryptionConfig.cs - configurable encryption modes (None, Unencrypted, Encrypted, Both)
- EncryptionManager.cs - encryption detection and initialization for login/game packets
- LoginEncryption.cs - handles login packet encryption with version-derived keys
- GameEncryption.cs - handles game server encryption using Twofish
- TwofishEngine.cs - optimized Twofish block cipher implementation
- LoginKeys.cs - encryption key table for client versions
- IClientEncryption.cs - interface for client encryption implementations
### NetState Improvements
- Replaced Socket Connection with RingSocket _socket for managed socket lifecycle
- Changed from GCHandle polling to event-based completion processing
- Disconnect handling now properly waits for pending sends to flush
- Simplified connecting socket management using lazy queue removal
### Configuration
- New settings: network.encryptionMode and network.encryptionDebug
- Encryption mode flags: Unencrypted, Encrypted, or Both
### Dependencies
- Replaced PollGroup NuGet package with IORingGroup
- Linux requires liburing-dev / liburing-devel package
### Test plan
- Verify server starts and accepts connections on Linux with io_uring
- Verify server starts and accepts connections on Windows (fallback to IOCP)
- Test unencrypted client connections (ClassicUO with encryption disabled)
- Test encrypted client connections if available
- Verify graceful disconnect flushes pending data
- Confirm CI builds pass on all target platforms
