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2cha - High-Performance VPN Utility

Minimalist VPN tool with IPv4/IPv6 dual-stack support, powered by ChaCha20-Poly1305 encryption.

Features

• IPv4/IPv6 Dual-Stack - Full support for both protocols
• High Performance - Optimized crypto and I/O
• Static Binary - Compile with musl for portable binaries
• Flexible Routing - Full tunnel or split tunnel modes
• Modern Crypto - ChaCha20-Poly1305 or AES-256-GCM

Quick Start

# Clone
git clone https://github.com/keepinfov/2cha
cd 2cha

# Build
cargo install --path .

# Generate key (save this!)
2cha genkey > vpn.key

# Create configs
2cha init server > server.toml
2cha init client > client.toml

# Edit configs, add key, then:

# On server
sudo 2cha server -c server.toml

# On client
sudo 2cha up -c client.toml

# Check status
2cha status

# Disconnect
sudo 2cha down

Static Build (Portable Binary)

# Install musl target
rustup target add x86_64-unknown-linux-musl

# Build static binary
cargo build --release --target x86_64-unknown-linux-musl

# Or use build script
./build.sh static

# For ARM64 (Raspberry Pi, etc.)
rustup target add aarch64-unknown-linux-musl
./build.sh static-arm

Configuration

Client (client.toml)

[client]
server = "vpn.example.com:51820"

[tun]
name = "tun0"
mtu = 1420

[crypto]
cipher = "chacha20-poly1305"
key = "your_64_char_hex_key"

# IPv4 settings
[ipv4]
enable = true
address = "10.0.0.2"
prefix = 24
route_all = true              # Full tunnel

# IPv6 settings
[ipv6]
enable = true
address = "fd00:2cha::2"
prefix = 64
route_all = true

# DNS
[dns]
servers_v4 = ["1.1.1.1", "8.8.8.8"]
servers_v6 = ["2606:4700:4700::1111"]

Server (server.toml)

[server]
listen = "0.0.0.0:51820"
max_clients = 256

[tun]
name = "tun0"
mtu = 1420

[crypto]
key = "same_key_as_clients"

[ipv4]
enable = true
address = "10.0.0.1"
prefix = 24

[ipv6]
enable = true
address = "fd00:2cha::1"
prefix = 64

[gateway]
ip_forward = true
ip6_forward = true
masquerade_v4 = true
masquerade_v6 = true
external_interface = "eth0"

Commands

Options

-c, --config <FILE>   Config file path
-d, --daemon          Run in background
-v, --verbose         Detailed output
-q, --quiet           Minimal output

Routing Modes

Split Tunnel (default)

Only VPN network traffic goes through VPN:

[ipv4]
route_all = false
routes = ["10.0.0.0/24", "192.168.100.0/24"]

Full Tunnel

ALL traffic goes through VPN:

[ipv4]
route_all = true

[ipv6]
route_all = true

[dns]
servers_v4 = ["1.1.1.1"]

Status Output

  2cha VPN Status
  ════════════════════════════════════════
  Status:     ● Connected
  Interface:  ● tun0
  IPv4:       10.0.0.2/24
  IPv6:       fd00:2cha::2/64
  Routing:    ● Full tunnel (v4+v6)
  Traffic:    ↓ 15.24 MB / ↑ 3.12 MB
  Public IP:  203.0.113.42

Performance Tuning

[performance]
socket_recv_buffer = 4194304  # 4MB for high throughput
socket_send_buffer = 4194304
batch_size = 64               # Larger batches
multi_queue = true            # Multi-queue TUN
cpu_affinity = [0, 1]         # Pin to CPUs

NixOS

You can build it using

# dynamic version 
nix build github:keepinfov/2cha

# static version (musl, supports aarch64 and x86_64) 
nix build github:keepinfov/2cha#static

# or if you wanna build by your own
git clone https://github.com/keepinfov/2cha
nix develop
cargo build --release

or you can just run it using

nix run github:keepinfov/2cha

License

MIT