Testing of 3.1-features

[leakingmemory]

With 3.0.7 the full set of features that I plan to add in 3.1.0 has been added under experimental configurations. By default vtun-embedded is going to run as similarly as possible to vtun 3.0.4. Please be aware that experimental features may not receive any security support like advisories and may change without backward and forward compatibility.

Features that are being tested for 3.1.0 are:

• Bidirectional authentication where the server also has to prove to the client that it knows the secret.
• Dropcaps, and dropping to non-root user in network context. This needs forking because the up and down commands usually requires root and capabilities.
• New configuration options for the client to validate minimum security requirements for the connection. (requires and accept_encrypt configs)
• New ciphers: aes128gcm, aes256gcm, aes128gcmsiv, aes256gcmsiv, chacha20poly1305.

Vtun-ng (rust) and vtun-embedded (C) are now companion projects. I'll try to keep them in sync.

The milestone 3.1.0 release can probably be expected in early 2026.

Long term compatibility:

• 3.1.0 and all other 3.X.X-releases are going to be compatible with vtun 3.0.4 by default.
• 4.X.X will be compatible with most of vtun 3.0.4 modes of operation, but not by default. (long term, 2028ish)