w5500-dns

DNS client for the Wiznet W5500 SPI internet offload chip.

Warning

Please proceed with caution, and review the code before use in a production environment.

This code was developed for one-off hobby projects.

Limitations

• No DNS caching.
• Only supports A queries.
• Only supports a single outstanding query.
• Only supports a single question in a query.

Example

use w5500_dns::{hl::block, ll::Sn, servers, Client as DnsClient, Hostname, Response};

const DNS_SOCKET: Sn = Sn::Sn3;
const DNS_SRC_PORT: u16 = 45917;

let mut dns_client: DnsClient =
    DnsClient::new(DNS_SOCKET, DNS_SRC_PORT, servers::CLOUDFLARE, random_number);
let hostname: Hostname = Hostname::new("docs.rs").expect("hostname is invalid");

let mut hostname_buffer: [u8; 16] = [0; 16];

let query_id: u16 = dns_client.a_question(&mut w5500, &hostname)?;
let mut response: Response<_> =
    block!(dns_client.response(&mut w5500, &mut hostname_buffer, query_id))?;

while let Some(rr) = response.next_rr()? {
    println!("name: {:?}", rr.name);
    println!("TTL: {}", rr.ttl);
    println!("IP: {:?}", rr.rdata);
}
response.done()?;

Relevant Specifications

• RFC 1035

Feature Flags

All features are disabled by default.

• eh0: Passthrough to w5500-hl.
• eh1: Passthrough to w5500-hl.
• defmt: Enable logging with defmt. Also a passthrough to w5500-hl.
• log: Enable logging with log.