TNT - Terminal Network Talk

A minimalist terminal chat server with Vim-style interface over SSH.

Features

• Zero config - Download and run, auto-generates SSH keys
• SSH-based - Leverage mature SSH protocol for encryption and auth
• Vim-style UI - Modal editing (INSERT/NORMAL/COMMAND)
• UTF-8 native - Full Unicode support
• High performance - Pure C, multi-threaded, sub-100ms startup
• Secure - Rate limiting, auth failure protection, input validation
• Persistent - Auto-saves chat history
• Elegant - Flicker-free TUI rendering

Quick Start

Installation

One-liner:

curl -sSL https://raw.githubusercontent.com/m1ngsama/TNT/main/install.sh | sh

From source:

git clone https://github.com/m1ngsama/TNT.git
cd TNT
make
sudo make install

Binary releases: https://github.com/m1ngsama/TNT/releases

Running

tnt              # default port 2222
tnt -p 3333      # custom port
PORT=3333 tnt    # via env var

Connecting

ssh -p 2222 localhost

Anonymous access by default: Users can connect with ANY username/password (or empty password). No SSH keys required. Perfect for public chat servers.

Usage

Keybindings

INSERT mode (default)

ESC        - Enter NORMAL mode
Enter      - Send message
Backspace  - Delete character
Ctrl+W     - Delete last word
Ctrl+U     - Delete line
Ctrl+C     - Enter NORMAL mode

NORMAL mode

i          - Return to INSERT mode
:          - Enter COMMAND mode
j/k        - Scroll down/up
g/G        - Scroll to top/bottom
?          - Show help

COMMAND mode

:list, :users, :who  - Show online users
:help, :commands     - Show available commands
:clear, :cls         - Clear command output
ESC                  - Return to NORMAL mode

Security Configuration

Access control:

# Require password
TNT_ACCESS_TOKEN="secret" tnt

# Bind to localhost only
TNT_BIND_ADDR=127.0.0.1 tnt

# Bind to specific IP
TNT_BIND_ADDR=192.168.1.100 tnt

Rate limiting:

# Max total connections (default 64)
TNT_MAX_CONNECTIONS=100 tnt

# Max connections per IP (default 5)
TNT_MAX_CONN_PER_IP=10 tnt

# Disable rate limiting (testing only)
TNT_RATE_LIMIT=0 tnt

SSH logging:

# 0=none, 1=warning, 2=protocol, 3=packet, 4=functions (default 1)
TNT_SSH_LOG_LEVEL=3 tnt

Production example:

TNT_ACCESS_TOKEN="strong-password-123" \
TNT_BIND_ADDR=0.0.0.0 \
TNT_MAX_CONNECTIONS=200 \
TNT_MAX_CONN_PER_IP=3 \
TNT_SSH_LOG_LEVEL=1 \
tnt -p 2222

Development

Building

make              # standard build
make debug        # debug build (with symbols)
make asan         # AddressSanitizer build
make check        # static analysis (cppcheck)
make clean        # clean build artifacts

Testing

make test         # run comprehensive test suite

# Individual tests
cd tests
./test_basic.sh              # basic functionality
./test_security_features.sh  # security features
./test_anonymous_access.sh   # anonymous access
./test_stress.sh             # stress test

Test coverage:

• Basic functionality: 3 tests
• Anonymous access: 2 tests
• Security features: 11 tests
• Stress test: concurrent connections

Dependencies

• libssh (>= 0.9.0) - SSH protocol library
• pthread - POSIX threads
• gcc/clang - C11 compiler

Ubuntu/Debian:

sudo apt-get install libssh-dev

macOS:

brew install libssh

Fedora/RHEL:

sudo dnf install libssh-devel

Project Structure

TNT/
├── src/              # source code
│   ├── main.c        # entry point
│   ├── ssh_server.c  # SSH server implementation
│   ├── chat_room.c   # chat room logic
│   ├── message.c     # message persistence
│   ├── tui.c         # terminal UI rendering
│   └── utf8.c        # UTF-8 character handling
├── include/          # header files
├── tests/            # test scripts
├── docs/             # documentation
├── scripts/          # operational scripts
├── Makefile          # build configuration
└── README.md         # this file

Deployment

systemd Service

sudo cp tnt.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable tnt
sudo systemctl start tnt

Docker

FROM alpine:latest
RUN apk add --no-cache libssh
COPY tnt /usr/local/bin/
EXPOSE 2222
CMD ["tnt"]

See docs/DEPLOYMENT.md for details.

Files

messages.log    - Chat history (RFC3339 format)
host_key        - SSH host key (auto-generated, 4096-bit RSA)
tnt.service     - systemd service unit

Documentation

• Development Guide - Complete development manual
• Quick Setup - 5-minute deployment guide
• Security Reference - Security config quick reference
• Contributing - How to contribute
• Changelog - Version history
• CI/CD - Continuous integration setup
• Quick Reference - Command cheat sheet

Performance

• Startup: < 100ms (even with 100k+ message history)
• Memory: ~2MB (idle)
• Concurrency: Supports 100+ concurrent connections
• Throughput: 1000+ messages/second

Known Limitations

• Single chat room (no multi-room support yet)
• Keeps only last 100 messages in memory
• Ctrl+W only recognizes ASCII space as word boundary

Contributing

Contributions welcome! See CONTRIBUTING.md

Process:

1. Fork the repository
2. Create feature branch (git checkout -b feature/AmazingFeature)
3. Commit changes (git commit -m 'Add some AmazingFeature')
4. Push to branch (git push origin feature/AmazingFeature)
5. Open Pull Request

License

MIT License - see LICENSE

Acknowledgments

• libssh - SSH protocol implementation
• Linux kernel community - Code style and engineering practices

Contact

• Issues: https://github.com/m1ngsama/TNT/issues
• Pull Requests: https://github.com/m1ngsama/TNT/pulls

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"Talk is cheap. Show me the code." - Linus Torvalds