Function recvfrom 

pub unsafe fn recvfrom(
    socket: CSocket,
    buf: MutBuf,
    len: BufLen,
    flags: c_int,
    addr: *mut SockAddr,
    addrlen: *mut SockLen,
) -> CouldFail

Call recvfrom(2) using raw socket arguments.

Safety

buf must be valid for writes of len bytes. addr and addrlen must point to writable storage for the returned socket address.