Add GFK_TCP_FLAGS setting to allow customizing TCP flags used in
violated TCP packets. This addresses cases where different flag
combinations (e.g. 'S', 'RA') may work better for certain networks.
Changes:
- Add tcp_flags parameter to vio_server.py and vio_client.py
- Add GFK_TCP_FLAGS to settings save/load with validation
- Add TCP flags menu option in change config for both server/client
- Default remains 'AP' for backwards compatibility
Validation: Only uppercase TCP flags allowed (F,S,R,P,A,U,E,C)
Features:
- Dual backend support: paqet (KCP) and GFW-knocker (violated TCP + QUIC)
- Both backends can run simultaneously when both are installed
- Automatic config.yaml generation for paqet backend
- Windows client support with PowerShell script
- Telegram monitoring integration
- Systemd service management
Backends:
- paqet: Single Go binary with built-in SOCKS5 (port 1080)
- GFW-knocker: Python-based with violated TCP tunneling (port 14000)
