## Summary
Two small additive changes that an external content assembly (ModernSpawner) needs, as separable commits.
**1. `SkillEvents.SkillUsed`** (`Projects/UOContent/Skills/SkillEvents.cs`, namespace `Server.Misc`): a plain C# event `Action<Mobile, Skill, bool success>` raised once per skill attempt from each of the four `Mobile_SkillCheck*` handlers, with the handler's own result. Attempts the handler resolves without a roll (too difficult, no challenge) raise too, so a grandmaster's trivial success and a guaranteed combat roll are observable. Not raised when the mobile lacks the skill. Each handler keeps its logic in a private core method and raises on the way out, so there is exactly one raise per attempt and `CheckSkill` itself is unchanged.
- **Why a plain event and not a `[GeneratedEvent]`:** generated events are compile-time static dispatch inside the UOContent compilation, so a subscriber in another assembly cannot use `[OnEvent]`. Shape follows `HelpEvents`.
- **Why "used", not "gained":** this is the XmlSpawner skill-trigger semantic (it wrapped the same four handlers and passed their result as `success`; its grammar was `Skill[+/-]` for success-only or failure-only). Gains are already observable through the existing skill-change notification on `Mobile`.
- **Cost:** one delegate null-check per attempt when nothing is subscribed; no boxing, no closure, no allocation. The handlers sit on the combat swing path.
- **Exception contract:** subscriber exceptions propagate, matching `EventSink`/`HelpEvents`; no try/catch by design.
**2. `InternalsVisibleTo("ModernSpawner.Tests")`** on `Server.csproj`, beside the existing `Server.Tests`/`UOContent.Tests` entries, so an external test host can seed `Core._now` the way the engine's own test initializers do. Separable; a public test seam on `Core` would serve the same need without naming a downstream assembly.
## Open question
The payload is the `Skill` object plus a positional `bool`. A `readonly struct` args type passed `in` would leave room to add `chance` or the target later without breaking subscribers. Happy to change before merge.
## Test plan
- [x] `UOContent.Tests`: 4 tests — a rolled attempt raises once with the returned outcome; each short-circuit path (no challenge, too difficult, on both the direct and value-window handlers) raises with the handler's result; a direct `CheckSkill` call does not raise; no subscriber does not throw. Full suite green.
- [x] `Server` and `UOContent` build clean with `TreatWarningsAsErrors`.
- [ ] CI
> [!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
> [!Important]
> **Developer Note**
> This code change will **completely move gumps out of the core**
### Summary
- Adds `GetGumps()` convenience which exposes methods to Find/Close/Send multiple gumps. This helper is a performance improvement by eliminating the Dictionary<Player, List> lookup for gumps.
### Summary
* Removes old gump packet support
* Removes support for v4 clients
* Removes `Unpack` flag and assumes it is always true.
* Removes StringToBuffer since this is built into .NET now.
> [!Note]
> View the file changes with white space off: https://github.com/modernuo/ModernUO/pull/1739/files?diff=split&w=1
## Breaking Changes
Incoming packet registration signature has changed to:
```cs
delegate* void OnReceiveCallback(NetState state, SpanReader reader, int packetLength);
IncomingPackets.Register(int packetID, int length, bool ingame, OnReceiveCallback onReceive);
```
For example, an incoming packet handler signature would now look like this:
```cs
public static void SomeIncomingPacket(NetState state, SpanReader reader, int packetLength)
{
// Parse the data
}
```
## Summary
Updates the network Pipe class to use a mirrored memory technique. This technique involves mapping the same physical memory to two contiguous virtual memory spaces so the byte buffer appears duplicated. This allows writing to a double-sized array to wrap around without the need for the `CircularBuffer` classes.
In practice this allows us to use `Span<byte>` as if the buffer was a regular array.
### Bug Fixes
- [X] Fixes bad fixed length string parsing
- [X] Cleans up gump packets
- [X] Adds event loop task synchronization
- [X] Moves timer pause and cleans up the delay task timer class
- [X] Cleans up the conserve cpu
- [X] Renames variables to make them consistent with the new style
- [X] Removes process delta recursion checking.
- [X] Properly diposes net states. This fixes edge cases that may cause hanging connections to stay open longer than they should.
- [X] Fixes an issue with gump items not compiling properly
Users can now utilize `Timer.Pause()` since the code will be executed on the proper thread.
```cs
public void async void Talk()
{
_canTalk = false;
await Timer.Pause(Utility.RandomMinMax(5000, 8000)); // Talk after 5-8 seconds
DoTalk();
await Timer.Pause(Utility.RandomMinMax(12000, 25000)); // Reset ability to talk after 12-25 seconds
_canTalk = true;
}
```
