From 779475eb3e30cecf6a8f925d2058d450a5ca0b47 Mon Sep 17 00:00:00 2001
From: Dan Fuhry <dan@fuhry.com>
Date: Sat, 29 Mar 2025 22:06:15 -0400
Subject: [PATCH] coredns_plugin: wildcard support for DNS records

---
 machines/coredns_plugin/registry.go       | 11 ++++++++++-
 machines/coredns_plugin/registry_store.go | 10 ++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/machines/coredns_plugin/registry.go b/machines/coredns_plugin/registry.go
index 43c4d19..0b6b608 100644
--- a/machines/coredns_plugin/registry.go
+++ b/machines/coredns_plugin/registry.go
@@ -292,7 +292,16 @@ func (r *registry) LookupRecord(ques dns.Question) (int, []dns.RR) {
 
 		records, ok := r.store.Records[domain.ID()][key]
 		if !ok {
-			continue
+			for _, wc := range key.Wildcards() {
+				records, ok = r.store.Records[domain.ID()][wc]
+				if ok {
+					r.log.V(2).Debugf("  query for %q matched on wildcard candidate %s", key, wc)
+					break
+				}
+			}
+			if !ok {
+				continue
+			}
 		}
 
 		answers := make([]dns.RR, 0)
diff --git a/machines/coredns_plugin/registry_store.go b/machines/coredns_plugin/registry_store.go
index 2fbece8..8958365 100644
--- a/machines/coredns_plugin/registry_store.go
+++ b/machines/coredns_plugin/registry_store.go
@@ -32,6 +32,16 @@ type registryStore struct {
 
 type recordKey string
 
+func (rk recordKey) Wildcards() []recordKey {
+	parts := strings.Split(string(rk), ".")
+	wildcards := make([]recordKey, len(parts))
+	for i, _ := range parts {
+		parts[i] = "*"
+		wildcards = append(wildcards, recordKey(strings.Join(parts[i:], ".")))
+	}
+	return wildcards
+}
+
 var machinesRegistryStorePath string
 
 func init() {
-- 
2.50.1