+ )
+ }
+
+ // split the string by ':' and convert the second part to u16
+ let mut parts_iter = s.rsplitn(2, ':');
+ let port_str = try_opt!(parts_iter.next(), "invalid socket address");
+ let host = try_opt!(parts_iter.next(), "invalid socket address");
+ let port: u16 = try_opt!(port_str.parse().ok(), "invalid port value");
+
+ (host, port).try_into()
+ }
+}
+
+impl<'a> TryFrom<(&'a str, u16)> for LookupHost {
+ type Error = io::Error;
+
+ fn try_from((host, port): (&'a str, u16)) -> io::Result<LookupHost> {
+ let mut ip_string = String::new();
+ File::open("/etc/net/ip")?.read_to_string(&mut ip_string)?;
+ let ip: Vec<u8> = ip_string.trim().split('.').map(|part| part.parse::<u8>()
+ .unwrap_or(0)).collect();
+
+ let mut dns_string = String::new();
+ File::open("/etc/net/dns")?.read_to_string(&mut dns_string)?;
+ let dns: Vec<u8> = dns_string.trim().split('.').map(|part| part.parse::<u8>()
+ .unwrap_or(0)).collect();
+
+ if ip.len() == 4 && dns.len() == 4 {
+ let time = time::SystemTime::now().duration_since(time::UNIX_EPOCH).unwrap();
+ let tid = (time.subsec_nanos() >> 16) as u16;
+
+ let packet = Dns {
+ transaction_id: tid,
+ flags: 0x0100,
+ queries: vec![DnsQuery {
+ name: host.to_string(),
+ q_type: 0x0001,
+ q_class: 0x0001,
+ }],
+ answers: vec![]
+ };
+
+ let packet_data = packet.compile();
+
+ let my_ip = Ipv4Addr::new(ip[0], ip[1], ip[2], ip[3]);
+ let dns_ip = Ipv4Addr::new(dns[0], dns[1], dns[2], dns[3]);
+ let socket = UdpSocket::bind(Ok(&SocketAddr::V4(SocketAddrV4::new(my_ip, 0))))?;
+ socket.set_read_timeout(Some(Duration::new(5, 0)))?;
+ socket.set_write_timeout(Some(Duration::new(5, 0)))?;
+ socket.connect(Ok(&SocketAddr::V4(SocketAddrV4::new(dns_ip, 53))))?;
+ socket.send(&packet_data)?;
+
+ let mut buf = [0; 65536];
+ let count = socket.recv(&mut buf)?;
+
+ match Dns::parse(&buf[.. count]) {
+ Ok(response) => {
+ let mut addrs = vec![];
+ for answer in response.answers.iter() {
+ if answer.a_type == 0x0001 && answer.a_class == 0x0001
+ && answer.data.len() == 4
+ {
+ let answer_ip = Ipv4Addr::new(answer.data[0],
+ answer.data[1],
+ answer.data[2],
+ answer.data[3]);
+ addrs.push(SocketAddr::V4(SocketAddrV4::new(answer_ip, 0)));
+ }
+ }
+ Ok(LookupHost(addrs.into_iter(), port))
+ },
+ Err(_err) => Err(Error::from_raw_os_error(EINVAL))
+ }
+ } else {
+ Err(Error::from_raw_os_error(EINVAL))