Resolv-conf

Status: Beta

A /etc/resolv.conf parser crate for rust.

Why?

1. There is no bare file parser in the crates.io at the moment
2. I needed one to make dns resolver for rotor

License

Licensed under either of

• Apache License, Version 2.0, (./LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (./LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

lib.rs:

The crate simply parses /etc/resolv.conf file and creates a config object

Examples

Parsing a config from a string

extern crate resolv_conf;

use std::net::{Ipv4Addr, Ipv6Addr};
use resolv_conf::{ScopedIp, Config, Network};

fn main() {
    let config_str = "
options ndots:8 timeout:8 attempts:8

domain example.com
search example.com sub.example.com

nameserver 2001:4860:4860::8888
nameserver 2001:4860:4860::8844
nameserver 8.8.8.8
nameserver 8.8.4.4

options rotate
options inet6 no-tld-query

sortlist 130.155.160.0/255.255.240.0 130.155.0.0";

    // Parse the config.
    let parsed_config = Config::parse(&config_str).expect("Failed to parse config");

    // We can build configs manually as well, either directly or with Config::new()
    let mut expected_config = Config::new();
    expected_config.nameservers = vec![
        ScopedIp::V6(Ipv6Addr::new(0x2001, 0x4860, 0x4860, 0, 0, 0, 0, 0x8888), None),
        ScopedIp::V6(Ipv6Addr::new(0x2001, 0x4860, 0x4860, 0, 0, 0, 0, 0x8844), None),
        ScopedIp::V4(Ipv4Addr::new(8, 8, 8, 8)),
        ScopedIp::V4(Ipv4Addr::new(8, 8, 4, 4)),
    ];
    expected_config.sortlist = vec![
        Network::V4(Ipv4Addr::new(130, 155, 160, 0), Ipv4Addr::new(255, 255, 240, 0)),
        Network::V4(Ipv4Addr::new(130, 155, 0, 0), Ipv4Addr::new(255, 255, 0, 0)),
    ];
    expected_config.debug = false;
    expected_config.ndots = 8;
    expected_config.timeout = 8;
    expected_config.attempts = 8;
    expected_config.rotate = true;
    expected_config.no_check_names = false;
    expected_config.inet6 = true;
    expected_config.ip6_bytestring = false;
    expected_config.ip6_dotint = false;
    expected_config.edns0 = false;
    expected_config.single_request = false;
    expected_config.single_request_reopen = false;
    expected_config.no_tld_query = true;
    expected_config.use_vc = false;
    expected_config.set_domain(String::from("example.com"));
    expected_config.set_search(vec![
        String::from("example.com"),
        String::from("sub.example.com")
    ]);

    // We can compare configurations, since resolv_conf::Config implements Eq
    assert_eq!(parsed_config, expected_config);
}

Parsing a file

use std::io::Read;
use std::fs::File;

extern crate resolv_conf;

fn main() {
    // Read the file
    let mut buf = Vec::with_capacity(4096);
    let mut f = File::open("/etc/resolv.conf").unwrap();
    f.read_to_end(&mut buf).unwrap();

    // Parse the buffer
    let cfg = resolv_conf::Config::parse(&buf).unwrap();

    // Print the config
    println!("---- Parsed /etc/resolv.conf -----\n{:#?}\n", cfg);
}