test(dns): add dns test cases for nodata

dns/dns_proxy_test.go

@@ -0,0 +1,178 @@
+package dns
+
+import (
+	"net"
+	"testing"
+
+	"github.com/miekg/dns"
+)
+
+func TestCheckLocalRecordsNODATAForAAAA(t *testing.T) {
+	proxy := &DNSProxy{
+		recordStore: NewDNSRecordStore(),
+	}
+
+	// Add an A record for a domain (no AAAA record)
+	ip := net.ParseIP("10.0.0.1")
+	err := proxy.recordStore.AddRecord("myservice.internal", ip)
+	if err != nil {
+		t.Fatalf("Failed to add A record: %v", err)
+	}
+
+	// Query AAAA for domain with only A record - should return NODATA
+	query := new(dns.Msg)
+	query.SetQuestion("myservice.internal.", dns.TypeAAAA)
+	response := proxy.checkLocalRecords(query, query.Question[0])
+
+	if response == nil {
+		t.Fatal("Expected NODATA response, got nil (would forward to upstream)")
+	}
+	if response.Rcode != dns.RcodeSuccess {
+		t.Errorf("Expected Rcode NOERROR (0), got %d", response.Rcode)
+	}
+	if len(response.Answer) != 0 {
+		t.Errorf("Expected empty answer section for NODATA, got %d answers", len(response.Answer))
+	}
+	if !response.Authoritative {
+		t.Error("Expected response to be authoritative")
+	}
+
+	// Query A for same domain - should return the record
+	query = new(dns.Msg)
+	query.SetQuestion("myservice.internal.", dns.TypeA)
+	response = proxy.checkLocalRecords(query, query.Question[0])
+
+	if response == nil {
+		t.Fatal("Expected response with A record, got nil")
+	}
+	if len(response.Answer) != 1 {
+		t.Fatalf("Expected 1 answer, got %d", len(response.Answer))
+	}
+	aRecord, ok := response.Answer[0].(*dns.A)
+	if !ok {
+		t.Fatal("Expected A record in answer")
+	}
+	if !aRecord.A.Equal(ip.To4()) {
+		t.Errorf("Expected IP %v, got %v", ip.To4(), aRecord.A)
+	}
+}
+
+func TestCheckLocalRecordsNODATAForA(t *testing.T) {
+	proxy := &DNSProxy{
+		recordStore: NewDNSRecordStore(),
+	}
+
+	// Add an AAAA record for a domain (no A record)
+	ip := net.ParseIP("2001:db8::1")
+	err := proxy.recordStore.AddRecord("ipv6only.internal", ip)
+	if err != nil {
+		t.Fatalf("Failed to add AAAA record: %v", err)
+	}
+
+	// Query A for domain with only AAAA record - should return NODATA
+	query := new(dns.Msg)
+	query.SetQuestion("ipv6only.internal.", dns.TypeA)
+	response := proxy.checkLocalRecords(query, query.Question[0])
+
+	if response == nil {
+		t.Fatal("Expected NODATA response, got nil")
+	}
+	if response.Rcode != dns.RcodeSuccess {
+		t.Errorf("Expected Rcode NOERROR (0), got %d", response.Rcode)
+	}
+	if len(response.Answer) != 0 {
+		t.Errorf("Expected empty answer section, got %d answers", len(response.Answer))
+	}
+	if !response.Authoritative {
+		t.Error("Expected response to be authoritative")
+	}
+
+	// Query AAAA for same domain - should return the record
+	query = new(dns.Msg)
+	query.SetQuestion("ipv6only.internal.", dns.TypeAAAA)
+	response = proxy.checkLocalRecords(query, query.Question[0])
+
+	if response == nil {
+		t.Fatal("Expected response with AAAA record, got nil")
+	}
+	if len(response.Answer) != 1 {
+		t.Fatalf("Expected 1 answer, got %d", len(response.Answer))
+	}
+	aaaaRecord, ok := response.Answer[0].(*dns.AAAA)
+	if !ok {
+		t.Fatal("Expected AAAA record in answer")
+	}
+	if !aaaaRecord.AAAA.Equal(ip) {
+		t.Errorf("Expected IP %v, got %v", ip, aaaaRecord.AAAA)
+	}
+}
+
+func TestCheckLocalRecordsNonExistentDomain(t *testing.T) {
+	proxy := &DNSProxy{
+		recordStore: NewDNSRecordStore(),
+	}
+
+	// Add a record so the store isn't empty
+	err := proxy.recordStore.AddRecord("exists.internal", net.ParseIP("10.0.0.1"))
+	if err != nil {
+		t.Fatalf("Failed to add record: %v", err)
+	}
+
+	// Query A for non-existent domain - should return nil (forward to upstream)
+	query := new(dns.Msg)
+	query.SetQuestion("unknown.internal.", dns.TypeA)
+	response := proxy.checkLocalRecords(query, query.Question[0])
+
+	if response != nil {
+		t.Error("Expected nil for non-existent domain, got response")
+	}
+
+	// Query AAAA for non-existent domain - should also return nil
+	query = new(dns.Msg)
+	query.SetQuestion("unknown.internal.", dns.TypeAAAA)
+	response = proxy.checkLocalRecords(query, query.Question[0])
+
+	if response != nil {
+		t.Error("Expected nil for non-existent domain, got response")
+	}
+}
+
+func TestCheckLocalRecordsNODATAWildcard(t *testing.T) {
+	proxy := &DNSProxy{
+		recordStore: NewDNSRecordStore(),
+	}
+
+	// Add a wildcard A record (no AAAA)
+	ip := net.ParseIP("10.0.0.1")
+	err := proxy.recordStore.AddRecord("*.wildcard.internal", ip)
+	if err != nil {
+		t.Fatalf("Failed to add wildcard A record: %v", err)
+	}
+
+	// Query AAAA for wildcard-matched domain - should return NODATA
+	query := new(dns.Msg)
+	query.SetQuestion("host.wildcard.internal.", dns.TypeAAAA)
+	response := proxy.checkLocalRecords(query, query.Question[0])
+
+	if response == nil {
+		t.Fatal("Expected NODATA response for wildcard match, got nil")
+	}
+	if response.Rcode != dns.RcodeSuccess {
+		t.Errorf("Expected Rcode NOERROR (0), got %d", response.Rcode)
+	}
+	if len(response.Answer) != 0 {
+		t.Errorf("Expected empty answer section, got %d answers", len(response.Answer))
+	}
+
+	// Query A for wildcard-matched domain - should return the record
+	query = new(dns.Msg)
+	query.SetQuestion("host.wildcard.internal.", dns.TypeA)
+	response = proxy.checkLocalRecords(query, query.Question[0])
+
+	if response == nil {
+		t.Fatal("Expected response with A record, got nil")
+	}
+	if len(response.Answer) != 1 {
+		t.Fatalf("Expected 1 answer, got %d", len(response.Answer))
+	}
+}