53 lines
1.4 KiB
Rust
53 lines
1.4 KiB
Rust
extern crate dns_parser;
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use std::env;
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use std::error::Error;
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use std::net::UdpSocket;
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use std::process;
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use dns_parser::{Builder, Packet, RData, ResponseCode};
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use dns_parser::rdata::a::Record;
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use dns_parser::{QueryType, QueryClass};
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fn main() {
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let mut code = 0;
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for name in env::args().skip(1) {
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match resolve(&name) {
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Ok(()) => {},
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Err(e) => {
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eprintln!("Error resolving {:?}: {}", name, e);
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code = 1;
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}
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}
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}
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process::exit(code);
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}
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fn resolve(name: &str) -> Result<(), Box<Error>> {
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let sock = UdpSocket::bind("127.0.0.1:0")?;
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sock.connect("127.0.0.1:53")?;
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let mut builder = Builder::new_query(1, true);
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builder.add_question(name, false, QueryType::A, QueryClass::IN);
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let packet = builder.build().map_err(|_| "truncated packet")?;
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sock.send(&packet)?;
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let mut buf = vec![0u8; 4096];
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sock.recv(&mut buf)?;
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let pkt = Packet::parse(&buf)?;
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if pkt.header.response_code != ResponseCode::NoError {
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return Err(pkt.header.response_code.into());
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}
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if pkt.answers.len() == 0 {
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return Err("No records received".into());
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}
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for ans in pkt.answers {
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match ans.data {
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RData::A(Record(ip)) => {
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println!("{}", ip);
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}
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_ => {} // ignore
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}
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}
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Ok(())
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}
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