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[release-1.28] removing CNAME record answer for wildcards (#1664) #1680

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Merged
istio-testing merged 1 commit into from
Nov 27, 2025
Merged

[release-1.28] removing CNAME record answer for wildcards (#1664) #1680

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69 changes: 15 additions & 54 deletions src/dns/server.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -258,20 +258,14 @@ impl Store {
// Insert an alias for a stripped search domain.
add_alias(Alias {
name: stripped_name.clone(),
stripped: Some(Stripped {
name: stripped_name.clone(),
search_domain: search_domain.clone(),
}),
stripped: Some(stripped_name.clone()),
});

// If the name can be expanded to a k8s FQDN, add that as well.
for kube_fqdn in self.to_kube_fqdns(&stripped_name, &namespaced_domain) {
add_alias(Alias {
name: kube_fqdn,
stripped: Some(Stripped {
name: stripped_name.clone(),
search_domain: search_domain.clone(),
}),
stripped: Some(stripped_name.clone()),
});
}
}
Expand Down Expand Up @@ -678,31 +672,14 @@ impl Resolver for Store {

// If the service was found by stripping off one of the search domains, create a
// CNAME record to map to the appropriate canonical name.
if let Some(stripped) = service_match.alias.stripped {
if service_match.name.is_wildcard() {
// The match is a wildcard...

// Create a CNAME record that maps from the wildcard with the search domain to
// the wildcard without it.
let cname_record_name = service_match
.name
.clone()
.append_domain(&stripped.search_domain)
.unwrap();
let canonical_name = service_match.name;
records.push(cname_record(cname_record_name, canonical_name));

// For wildcards, continue using the original requested hostname for IP records.
} else {
// The match is NOT a wildcard...

// Create a CNAME record to map from the requested name -> stripped name.
let canonical_name = stripped.name;
records.push(cname_record(requested_name.clone(), canonical_name.clone()));

// Also use the stripped name as the IP record name.
ip_record_name = canonical_name;
}
if let Some(stripped) = service_match.alias.stripped
&& !service_match.name.is_wildcard()
{
// Create a CNAME record to map from the requested name -> stripped name.
records.push(cname_record(requested_name.clone(), stripped.clone()));

// Also use the stripped name as the IP record name.
ip_record_name = stripped;
}

access_log(request, Some(&client), "success", records.len());
Expand Down Expand Up @@ -743,7 +720,7 @@ struct Alias {

/// If `Some`, indicates that this alias was generated from the requested host that
/// was stripped of
stripped: Option<Stripped>,
stripped: Option<Name>,
}

impl Display for Alias {
Expand All @@ -752,16 +729,6 @@ impl Display for Alias {
}
}

/// Created for an alias generated by stripping a search domain from the requested host.
#[derive(Debug)]
struct Stripped {
/// The requested hostname with the `search_domain` removed.
name: Name,

/// The search domain that was removed from the requested host to generate `name`.
search_domain: Name,
}

/// Returned when a server was successfully found for the requested hostname.
#[derive(Debug)]
struct ServerMatch {
Expand Down Expand Up @@ -1329,16 +1296,10 @@ mod tests {
Case {
name: "success: wild card with search domain returns A record correctly",
host: "foo.svc.mesh.company.net.ns1.svc.cluster.local.",
expect_records: vec![
cname(
n("*.svc.mesh.company.net.ns1.svc.cluster.local."),
n("*.svc.mesh.company.net."),
),
a(
n("foo.svc.mesh.company.net.ns1.svc.cluster.local."),
ipv4("10.1.2.3"),
),
],
expect_records: vec![a(
n("foo.svc.mesh.company.net.ns1.svc.cluster.local."),
ipv4("10.1.2.3"),
)],
..Default::default()
},
Case {
Expand Down