121 lines
3.7 KiB
Rust

//! DNS client compatible with the `embedded-nal-async` traits.
//!
//! This exists only for compatibility with crates that use `embedded-nal-async`.
//! Prefer using [`Stack::dns_query`](crate::Stack::dns_query) directly if you're
//! not using `embedded-nal-async`.
use heapless::Vec;
pub use smoltcp::socket::dns::{DnsQuery, Socket};
pub(crate) use smoltcp::socket::dns::{GetQueryResultError, StartQueryError};
pub use smoltcp::wire::{DnsQueryType, IpAddress};
use crate::Stack;
/// Errors returned by DnsSocket.
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum Error {
/// Invalid name
InvalidName,
/// Name too long
NameTooLong,
/// Name lookup failed
Failed,
}
impl From<GetQueryResultError> for Error {
fn from(_: GetQueryResultError) -> Self {
Self::Failed
}
}
impl From<StartQueryError> for Error {
fn from(e: StartQueryError) -> Self {
match e {
StartQueryError::NoFreeSlot => Self::Failed,
StartQueryError::InvalidName => Self::InvalidName,
StartQueryError::NameTooLong => Self::NameTooLong,
}
}
}
/// DNS client compatible with the `embedded-nal-async` traits.
///
/// This exists only for compatibility with crates that use `embedded-nal-async`.
/// Prefer using [`Stack::dns_query`](crate::Stack::dns_query) directly if you're
/// not using `embedded-nal-async`.
pub struct DnsSocket<'a> {
stack: Stack<'a>,
}
impl<'a> DnsSocket<'a> {
/// Create a new DNS socket using the provided stack.
///
/// NOTE: If using DHCP, make sure it has reconfigured the stack to ensure the DNS servers are updated.
pub fn new(stack: Stack<'a>) -> Self {
Self { stack }
}
/// Make a query for a given name and return the corresponding IP addresses.
pub async fn query(
&self,
name: &str,
qtype: DnsQueryType,
) -> Result<Vec<IpAddress, { smoltcp::config::DNS_MAX_RESULT_COUNT }>, Error> {
self.stack.dns_query(name, qtype).await
}
}
impl<'a> embedded_nal_async::Dns for DnsSocket<'a> {
type Error = Error;
async fn get_host_by_name(
&self,
host: &str,
addr_type: embedded_nal_async::AddrType,
) -> Result<core::net::IpAddr, Self::Error> {
use core::net::IpAddr;
use embedded_nal_async::AddrType;
let (qtype, secondary_qtype) = match addr_type {
AddrType::IPv4 => (DnsQueryType::A, None),
AddrType::IPv6 => (DnsQueryType::Aaaa, None),
AddrType::Either => {
#[cfg(not(feature = "proto-ipv6"))]
let v6_first = false;
#[cfg(feature = "proto-ipv6")]
let v6_first = self.stack.config_v6().is_some();
match v6_first {
true => (DnsQueryType::Aaaa, Some(DnsQueryType::A)),
false => (DnsQueryType::A, Some(DnsQueryType::Aaaa)),
}
}
};
let mut addrs = self.query(host, qtype).await?;
if addrs.is_empty() {
if let Some(qtype) = secondary_qtype {
addrs = self.query(host, qtype).await?
}
}
if let Some(first) = addrs.get(0) {
Ok(match first {
#[cfg(feature = "proto-ipv4")]
IpAddress::Ipv4(addr) => IpAddr::V4(*addr),
#[cfg(feature = "proto-ipv6")]
IpAddress::Ipv6(addr) => IpAddr::V6(*addr),
})
} else {
Err(Error::Failed)
}
}
async fn get_host_by_address(&self, _addr: core::net::IpAddr, _result: &mut [u8]) -> Result<usize, Self::Error> {
todo!()
}
}
fn _assert_covariant<'a, 'b: 'a>(x: DnsSocket<'b>) -> DnsSocket<'a> {
x
}