OpenWrt helper scripts

Lightweight collection of small shell scripts and helpers aimed at OpenWrt-based routers and devices. Each script is self-contained and lives under Scripts/ with its own README detailing options and examples.

Contents

• Scripts/nft-ttl-adjust/ - Helper to adjust packet TTLs (nftables-based helper). See Scripts/nft-ttl-adjust/README.md for details and usage examples.
• Scripts/usb-tether-monitor/ - Monitor USB tethering state and run user-defined hooks (bring interface up/down, notify, log). See Scripts/usb-tether-monitor/README.md for details.

Intended use / contract

• Inputs: shell environment on an OpenWrt or Linux-based router, installed dependencies noted in each script's README (usually nft, ip, grep, awk, busybox utilities).
• Outputs: script-specific actions (nft rules adjustments, interface state changes, logs) and informative exit codes (0 on success, non-zero on error).
• Error modes: missing dependencies, insufficient permissions (scripts need to run as root), unsupported kernel/netfilter configuration.

If something needs root privileges the script will usually indicate it — run under root or via an init/hotplug mechanism on OpenWrt.

Quick start

1. Inspect the per-script README files for configuration and examples:

   • Scripts/nft-ttl-adjust/README.md
   • Scripts/usb-tether-monitor/README.md

2. Make a copy to your router and mark executable:

# copy to router (example using scp)
scp -r Scripts/* root@your-router:/usr/local/bin/

# on the router
chmod +x /usr/local/bin/nft-ttl-adjust.sh
chmod +x /usr/local/bin/usb-tether-monitor.sh

1. Run manually for testing, then install as a service, hotplug or cron job as appropriate for your setup. On OpenWrt you can integrate scripts via /etc/init.d/ or add them to hotplug events.

Examples

See the embedded README in each script's folder for concrete command-line examples. Example (testing on a router shell):

# run the USB tether monitor once (interactive test)
/usr/local/bin/usb-tether-monitor.sh --test

# show nft-ttl-adjust help
/usr/local/bin/nft-ttl-adjust.sh --help

Requirements

• OpenWrt or a Linux-based router
• nft (nftables) for nft-ttl-adjust if you plan to use nft-based rules
• BusyBox coreutils (installed by default on OpenWrt)
• Root or equivalent privileges to modify interfaces and firewall/nft rules

If you're missing a tool, check the per-script README where common requirements are listed.

Troubleshooting

• Script exits with permission errors: re-run as root or via sudo/procd/init.d.
• nft operations fail: verify nft is installed and kernel supports nftables.
• USB tethering not detected: check dmesg and logread on OpenWrt; ensure your device enumerates as a network interface.

For persistent issues, enable debug/logging shown in each script's README and file an issue with logs attached.

Contributing

Contributions are welcome. Please open a pull request with:

• A short description of the change
• Why it's needed (bug, feature, portability)
• Minimal test instructions

Keep changes small and script-compatible with BusyBox shells where possible.

License

These scripts are provided under the MIT License — see LICENSE if present in this repository. If no license file exists, contact the repository owner for clarification before reuse in production.

Notes / assumptions

• These scripts were written as small utilities for OpenWrt-style environments; they assume a POSIX-like shell and common utilities are available.
• For full, authoritative usage follow each script's README in Scripts/<script-name>/README.md.

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If you'd like, I can also:

• Extract and summarize the usage examples from each script's README and embed them into this root README.
• Add an explicit LICENSE file (MIT) if you want to publish this repository with permissive licensing.