Of course. You can't do anything fundamentally in Rust that you couldn't do in C or C++ or Assembly. You can just do it a lot easier and with fewer bugs.
I think Rust+C is way more effective (and by that i mean easy to write) than Rust or C alone, and i would bet that "Rust-written" in the title really mean "Rust+C".
It's BPF-based so I imagine the meaningful part is already written in C.