You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: linux.rs
    path of file: ./repos/shadowsocks-rust/crates/shadowsocks-service/src/local/redir/tcprelay/sys/unix
    
    the code of the file until where you have to start completion: use std::{
    io::{self, Error, ErrorKind},
    mem,
    net::SocketAddr,
    os::unix::io::AsRawFd,
};

use async_trait::async_trait;
use log::warn;
use shadowsocks::net::{is_dual_stack_addr, set_tc
    
    fn destination_addr(&self, ty: RedirType) -> io::Result<SocketAddr> {
        match ty {
            RedirType::Redirect => get_original_destination_addr(self),
            RedirType::TProxy => {
                // For TPROXY, uses getsockname() to retrieve original destination address
                self.local_addr()
            }
            _ => unreachable!("not supported tcp transparent proxy type"),
        }
    }