Function rawsocket_helper::send::build_l2_tcp_packet

pub fn build_l2_tcp_packet(
    tx_packet: &mut [u8], 
    body_size: usize, 
    src_mac: &MacAddr, 
    dst_mac: &MacAddr, 
    src_ip: &Ipv4Addr, 
    dst_ip: &Ipv4Addr, 
    src_port: u16, 
    dst_port: u16, 
    seq: u32, 
    rng: &mut ThreadRng
)

构造 L2 + L3 + L4 TCP 包