NativeSockets2 1.6.0

NativeSockets2

A P/Invoke wrapper over a native C UDP socket library, providing the same API as NativeSockets with a native backend.

About

• NativeSockets2 is a lightweight, cross‑platform library for UDP networking.
• It is a P/Invoke wrapper around a native C library, delivering high performance through a native implementation.
• The library exposes the exact same public API as NativeSockets, making it a drop‑in replacement.
• Precompiled native binaries are included for all supported platforms and architectures.

Supported Platforms

• Windows
• Linux
• Android
• macOS
• iOS
• tvOS
• watchOS
• visionOS

Key Features

• Zero garbage collection pressure
• Same API as NativeSockets – seamless switching between managed and native backends.
• Complete UDP support – create, bind, connect, send, receive, and poll sockets.
• Ipv4 and Ipv6 with dual‑mode support.
• Scatter/gather I/O – Efficient vectored send and receive operations.

Native Library Dependency

• The NuGet package includes the native C library for all supported platforms.
• The correct binary is loaded automatically at runtime – no extra installation or configuration is needed.
• Just add the package and use the same API as you would with the original NativeSockets.
• You can build binaries using GitHub Actions.

VirtualSocket

A unified socket type that automatically picks the best available backend at runtime:

• When NativeSocketPal.IsSupported is true, VirtualSocket is backed by the native socket implementation.
• Otherwise, it transparently falls back to System.Net.Sockets.Socket.

Key Points

• No manual NativeSocketPal.Startup / NativeSocketPal.Cleanup calls are required – the underlying socket subsystem is managed automatically.
• The send/receive API mirrors the native socket API and returns an IoResult (byte count plus SocketError).
• SocketFlags are restricted: send operations honor only None and DontRoute; receive operations honor only None and Peek. Any other flags are silently ignored.
• For vectored receive operations, truncated data is reported as IoResult.Err with SocketError.MessageSize, even when the underlying operation succeeded.

Notes

• On the managed fallback path, a SendTo that triggers an implicit bind leaves the socket actually bound, but LocalEndPoint cannot be queried and throws. This only occurs on .NET 8 and later, because the SendTo(ReadOnlySpan<byte>, SocketFlags, SocketAddress) overload does not set the underlying _rightEndPoint field. In that state GetName reports an error even though the datagram was delivered.
• The managed fallback path carries the overhead of System.Net.Sockets; prefer the native backend when performance matters.
• When NativeSocketPal.IsSupported is false and the socket is non-blocking, consider polling with Poll or PollFlags before sending or receiving, because frequent SocketError.WouldBlock exceptions have a severe impact on performance.