BSDSocker

Author's Note (2020.2.9) ↝ I do not plan to pick this project back up again. A significant amount of its functionality – such as sniffing packets containing payloads in a variety of formats and determining many details about them – is complete. Other features, such as injection, are not – but should be easy to figure out based on the existing code. Hopefully it can serve as a starting-point or an educational example for others.

A basic command-line packet sniffer and injector for BSD-based systems (e.g. macOS). The goal of this project is that it:

• Compiles with any C compiler on any BSD-based system
• Works on any BSD-based system that provides the BPF device (try man bpf)
• Is written and architected in an extremely clean, readable, and thus referenceable way

Because BSD-based systems handle raw sockets differently than other Unix-y systems, packet sniffers and injectors have to be written differently. Specifically, BSD provides a special system device for interacting with the raw network data coming over a given network device. This project is an attempt to make use of said special device.

For more information, check out Using FreeBSD's BPF device with C/C++ by Bastian Rieck.