doh-dns

A library to make DNS over HTTPS requests.

Documentation

Overview

This DNS over HTTPS (DoH) library queries public DoH servers provided by Google and Clouflare. It is based on async/await with the help of hyper and tokio.

The library supports timeouts and retries which can be fully customized. A utility in the dohdns directory is provided in this crate to use this library in the command line.

Quick Start

To quickly get started, a default client can be created with Dns:default() and A records can be queried using Dns::resolve_a(). The default resolvers use Google first with a timeout of 3 seconds and Clouflare second with a timeout of 10 seconds. Note: Cloudlare does not support queries for ANY records. You can use the Google resolver for that.

Example

use doh_dns::{client::HyperDnsClient, Dns, DnsHttpsServer};
use std::time::Duration;
use tokio;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // The following sets up the main DoH server to be Google with a default timeout
    // of 2 seconds. If a retry is needed, the Cloudflare's 1.1.1.1 server is used.
    // Alternatively, the default server setup can be used with:
    // let dns = Dns::default();
    let dns: Dns<HyperDnsClient> = Dns::with_servers(&[
        DnsHttpsServer::Google(Duration::from_secs(2)),
        DnsHttpsServer::Cloudflare1_1_1_1(Duration::from_secs(10)),
    ])
    .unwrap();
    match dns.resolve_a("www.cloudflare.com").await {
        Ok(responses) => {
            if responses.is_empty() {
                println!("No entries found.");
            } else {
                for res in responses {
                    println!(
                        "name: {}, type: {}, TTL: {}, data: {}",
                        res.name,
                        dns.rtype_to_name(res.r#type),
                        res.TTL,
                        res.data
                    );
                }
            }
        }
        Err(err) => println!("Error: {}", err),
    }
    Ok(())
}

Logging

This library uses the log crate to log errors during retries. Please see that create on methods on display such errors. If no logger is setup, nothing will be logged.