fix: Add DNS resolver to oidc crate as well

Because openidconnect vendors reqwest (??), we have to re-implement
the entire Resolve trait.

No I don't like it, but I can't think of a better solution.

src/service/client/dns_resolver.rs

@@ -4,18 +4,20 @@ use std::{
 };
 
 use hickory_resolver::{Resolver, net::runtime::TokioRuntimeProvider};
-use reqwest::dns::{Addrs, Name, Resolve, Resolving};
+use reqwest::dns::{Addrs, Resolving};
 
 /// A simple struct to implement reqwest::dns::Resolve, as that is what's
 /// required by the reqwest client builder. Most code is based on
 /// reqwest::dns::HickoryDnsResolver, which we here have to almost re-create
 /// because it's pub(crate) instead of pub:
-pub(crate) struct DnsResolver {
-	resolver: Arc<Resolver<TokioRuntimeProvider>>,
+pub struct DnsResolver {
+	resolver: Arc<TokioResolver>,
 }
 
+type TokioResolver = Resolver<TokioRuntimeProvider>;
+
 impl DnsResolver {
-	pub(crate) fn new(resolver: Arc<Resolver<TokioRuntimeProvider>>) -> Self { Self { resolver } }
+	pub(crate) fn new(resolver: Arc<TokioResolver>) -> Self { Self { resolver } }
 }
 
 struct SocketAddrs {
@@ -30,8 +32,23 @@ impl Iterator for SocketAddrs {
 	}
 }
 
-impl Resolve for DnsResolver {
-	fn resolve(&self, name: Name) -> Resolving {
+impl reqwest::dns::Resolve for DnsResolver {
+	fn resolve(&self, name: reqwest::dns::Name) -> Resolving {
+		let resolver = self.resolver.clone();
+		Box::pin(async move {
+			let lookup = resolver.lookup_ip(name.as_str()).await?;
+			let addrs: Addrs = Box::new(SocketAddrs {
+				iter: lookup.iter().collect::<Vec<_>>().into_iter(),
+			});
+			Ok(addrs)
+		})
+	}
+}
+
+// openidconnect is weird and vendors reqwest (?), therefore we have to
+// completely re-implement Resolve with different types
+impl openidconnect::reqwest::dns::Resolve for DnsResolver {
+	fn resolve(&self, name: openidconnect::reqwest::dns::Name) -> Resolving {
 		let resolver = self.resolver.clone();
 		Box::pin(async move {
 			let lookup = resolver.lookup_ip(name.as_str()).await?;