plugin/k8s_external: Persist tc bit from lookup to client response (#4716)

* persist reponse tc bit from lookup to client
Signed-off-by: Chris O'Haver <cohaver@infoblox.com>

plugin/k8s_external/external.go

@@ -99,9 +99,9 @@ func (e *External) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Ms
 
 	switch state.QType() {
 	case dns.TypeA:
-		m.Answer = e.a(ctx, svc, state)
+		m.Answer, m.Truncated = e.a(ctx, svc, state)
 	case dns.TypeAAAA:
-		m.Answer = e.aaaa(ctx, svc, state)
+		m.Answer, m.Truncated = e.aaaa(ctx, svc, state)
 	case dns.TypeSRV:
 		m.Answer, m.Extra = e.srv(ctx, svc, state)
 	default:

plugin/k8s_external/external_test.go

@@ -62,7 +62,7 @@ var tests = []test.Case{
 	{
 		Qname: "svc1.testns.example.com.", Qtype: dns.TypeSRV, Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{test.SRV("svc1.testns.example.com.	5	IN	SRV	0 100 80 svc1.testns.example.com.")},
-		Extra: []dns.RR{test.A("svc1.testns.example.com.  5       IN      A       1.2.3.4")},
+		Extra:  []dns.RR{test.A("svc1.testns.example.com.  5       IN      A       1.2.3.4")},
 	},
 	// SRV Service Not udp/tcp
 	{

plugin/k8s_external/msg_to_dns.go

@@ -10,7 +10,7 @@ import (
 	"github.com/miekg/dns"
 )
 
-func (e *External) a(ctx context.Context, services []msg.Service, state request.Request) (records []dns.RR) {
+func (e *External) a(ctx context.Context, services []msg.Service, state request.Request) (records []dns.RR, truncated bool) {
 	dup := make(map[string]struct{})
 
 	for _, s := range services {
@@ -23,6 +23,9 @@ func (e *External) a(ctx context.Context, services []msg.Service, state request.
 			records = append(records, rr)
 			if resp, err := e.upstream.Lookup(ctx, state, dns.Fqdn(s.Host), dns.TypeA); err == nil {
 				records = append(records, resp.Answer...)
+				if resp.Truncated {
+					truncated = true
+				}
 			}
 
 		case dns.TypeA:
@@ -37,10 +40,10 @@ func (e *External) a(ctx context.Context, services []msg.Service, state request.
 			// nada
 		}
 	}
-	return records
+	return records, truncated
 }
 
-func (e *External) aaaa(ctx context.Context, services []msg.Service, state request.Request) (records []dns.RR) {
+func (e *External) aaaa(ctx context.Context, services []msg.Service, state request.Request) (records []dns.RR, truncated bool) {
 	dup := make(map[string]struct{})
 
 	for _, s := range services {
@@ -53,6 +56,9 @@ func (e *External) aaaa(ctx context.Context, services []msg.Service, state reque
 			records = append(records, rr)
 			if resp, err := e.upstream.Lookup(ctx, state, dns.Fqdn(s.Host), dns.TypeAAAA); err == nil {
 				records = append(records, resp.Answer...)
+				if resp.Truncated {
+					truncated = true
+				}
 			}
 
 		case dns.TypeA:
@@ -67,7 +73,7 @@ func (e *External) aaaa(ctx context.Context, services []msg.Service, state reque
 			}
 		}
 	}
-	return records
+	return records, truncated
 }
 
 func (e *External) srv(ctx context.Context, services []msg.Service, state request.Request) (records, extra []dns.RR) {

plugin/k8s_external/transfer.go

@@ -55,11 +55,11 @@ func (e *External) Transfer(zone string, serial uint32) (<-chan []dns.RR, error)
 			if svcs[i].TargetStrip == 0 {
 				// Add Service A/AAAA records
 				s := request.Request{Req: &dns.Msg{Question: []dns.Question{{Name: name}}}}
-				as := e.a(ctx, []msg.Service{svcs[i]}, s)
+				as, _ := e.a(ctx, []msg.Service{svcs[i]}, s)
 				if len(as) > 0 {
 					ch <- as
 				}
-				aaaas := e.aaaa(ctx, []msg.Service{svcs[i]}, s)
+				aaaas, _ := e.aaaa(ctx, []msg.Service{svcs[i]}, s)
 				if len(aaaas) > 0 {
 					ch <- aaaas
 				}