plugin/etcd+kubernetes: Persist truncated state to client if CNAME lookup response is truncated (#4715)

Persist the TC bit to client response for truncated CNAME lookups.
Signed-off-by: Chris O'Haver <cohaver@infoblox.com>

1 files changed, 155 insertions, 81 deletions

diff --git a/plugin/kubernetes/handler_test.go b/plugin/kubernetes/handler_test.go
index 4ff931ba1..523341fda 100644
--- a/plugin/kubernetes/handler_test.go
+++ b/plugin/kubernetes/handler_test.go
@@ -8,48 +8,56 @@ import (
 	"github.com/coredns/coredns/plugin/kubernetes/object"
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
 	"github.com/coredns/coredns/plugin/test"
+	"github.com/coredns/coredns/request"
 
 	"github.com/miekg/dns"
 	api "k8s.io/api/core/v1"
 	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
-var dnsTestCases = []test.Case{
+type kubeTestCase struct {
+	Upstream  Upstreamer
+	Truncated bool
+	test.Case
+}
+
+var dnsTestCases = []kubeTestCase{
 	// A Service
-	{
+	{Case: test.Case{
 		Qname: "svc1.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("svc1.testns.svc.cluster.local.	5	IN	A	10.0.0.1"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "svcempty.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("svcempty.testns.svc.cluster.local.	5	IN	A	10.0.0.1"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "svc1.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{test.SRV("svc1.testns.svc.cluster.local.	5	IN	SRV	0 100 80 svc1.testns.svc.cluster.local.")},
 		Extra: []dns.RR{test.A("svc1.testns.svc.cluster.local.  5       IN      A       10.0.0.1")},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "svcempty.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{test.SRV("svcempty.testns.svc.cluster.local.	5	IN	SRV	0 100 80 svcempty.testns.svc.cluster.local.")},
 		Extra: []dns.RR{test.A("svcempty.testns.svc.cluster.local.  5       IN      A       10.0.0.1")},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "svc6.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{test.SRV("svc6.testns.svc.cluster.local.	5	IN	SRV	0 100 80 svc6.testns.svc.cluster.local.")},
 		Extra: []dns.RR{test.AAAA("svc6.testns.svc.cluster.local.  5       IN      AAAA       1234:abcd::1")},
-	},
+	}},
 	// SRV Service
-	{
+	{Case: test.Case{
+
 		Qname: "_http._tcp.svc1.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
@@ -58,8 +66,9 @@ var dnsTestCases = []test.Case{
 		Extra: []dns.RR{
 			test.A("svc1.testns.svc.cluster.local.	5	IN	A	10.0.0.1"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
+
 		Qname: "_http._tcp.svcempty.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
@@ -68,9 +77,9 @@ var dnsTestCases = []test.Case{
 		Extra: []dns.RR{
 			test.A("svcempty.testns.svc.cluster.local.	5	IN	A	10.0.0.1"),
 		},
-	},
+	}},
 	// A Service (Headless)
-	{
+	{Case: test.Case{
 		Qname: "hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
@@ -79,50 +88,50 @@ var dnsTestCases = []test.Case{
 			test.A("hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.4"),
 			test.A("hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.5"),
 		},
-	},
+	}},
 	// A Service (Headless and Portless)
-	{
+	{Case: test.Case{
 		Qname: "hdlsprtls.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("hdlsprtls.testns.svc.cluster.local.	5	IN	A	172.0.0.20"),
 		},
-	},
+	}},
 	// An Endpoint with no port
-	{
+	{Case: test.Case{
 		Qname: "172-0-0-20.hdlsprtls.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("172-0-0-20.hdlsprtls.testns.svc.cluster.local.	5	IN	A	172.0.0.20"),
 		},
-	},
+	}},
 	// An Endpoint ip
-	{
+	{Case: test.Case{
 		Qname: "172-0-0-2.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("172-0-0-2.hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.2"),
 		},
-	},
+	}},
 	// A Endpoint ip
-	{
+	{Case: test.Case{
 		Qname: "172-0-0-3.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("172-0-0-3.hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.3"),
 		},
-	},
+	}},
 	// An Endpoint by name
-	{
+	{Case: test.Case{
 		Qname: "dup-name.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("dup-name.hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.4"),
 			test.A("dup-name.hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.5"),
 		},
-	},
+	}},
 	// SRV Service (Headless)
-	{
+	{Case: test.Case{
 		Qname: "_http._tcp.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
@@ -140,8 +149,8 @@ var dnsTestCases = []test.Case{
 			test.A("dup-name.hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.4"),
 			test.A("dup-name.hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.5"),
 		},
-	},
-	{ // An A record query for an existing headless service should return a record for each of its ipv4 endpoints
+	}},
+	{Case: test.Case{ // An A record query for an existing headless service should return a record for each of its ipv4 endpoints
 		Qname: "hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
@@ -150,96 +159,120 @@ var dnsTestCases = []test.Case{
 			test.A("hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.4"),
 			test.A("hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.5"),
 		},
-	},
+	}},
 	// AAAA
-	{
+	{Case: test.Case{
 		Qname: "5678-abcd--2.hdls1.testns.svc.cluster.local", Qtype: dns.TypeAAAA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{test.AAAA("5678-abcd--2.hdls1.testns.svc.cluster.local.	5	IN	AAAA	5678:abcd::2")},
-	},
+	}},
 	// CNAME External
-	{
+	{Case: test.Case{
 		Qname: "external.testns.svc.cluster.local.", Qtype: dns.TypeCNAME,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.CNAME("external.testns.svc.cluster.local.	5	IN	CNAME	ext.interwebs.test."),
 		},
+	}},
+	// CNAME External Truncated Lookup
+	{
+		Case: test.Case{
+			Qname: "external.testns.svc.cluster.local.", Qtype: dns.TypeA,
+			Rcode: dns.RcodeSuccess,
+			Answer: []dns.RR{
+				test.A("ext.interwebs.test.	5	IN	A	1.2.3.4"),
+				test.CNAME("external.testns.svc.cluster.local.	5	IN	CNAME	ext.interwebs.test."),
+			},
+		},
+		Upstream: &Upstub{
+			Truncated: true,
+			Qclass:    dns.ClassINET,
+			Case: test.Case{
+				Qname: "external.testns.svc.cluster.local.",
+				Qtype: dns.TypeA,
+				Answer: []dns.RR{
+					test.A("ext.interwebs.test.	5	IN	A	1.2.3.4"),
+					test.CNAME("external.testns.svc.cluster.local.	5	IN	CNAME	ext.interwebs.test."),
+				},
+			},
+		},
+		Truncated: true,
 	},
 	// CNAME External To Internal Service
-	{
+	{Case: test.Case{
 		Qname: "external-to-service.testns.svc.cluster.local", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.CNAME("external-to-service.testns.svc.cluster.local.	5	IN	CNAME	svc1.testns.svc.cluster.local."),
 			test.A("svc1.testns.svc.cluster.local.	5	IN	A	10.0.0.1"),
 		},
-	},
+	}},
 	// AAAA Service (with an existing A record, but no AAAA record)
-	{
+	{Case: test.Case{
 		Qname: "svc1.testns.svc.cluster.local.", Qtype: dns.TypeAAAA,
 		Rcode: dns.RcodeSuccess,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// AAAA Service (non-existing service)
-	{
+	{Case: test.Case{
 		Qname: "svc0.testns.svc.cluster.local.", Qtype: dns.TypeAAAA,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// A Service (non-existing service)
-	{
+	{Case: test.Case{
 		Qname: "svc0.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// A Service (non-existing namespace)
-	{
+	{Case: test.Case{
 		Qname: "svc0.svc-nons.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// TXT Schema
-	{
+	{Case: test.Case{
 		Qname: "dns-version.cluster.local.", Qtype: dns.TypeTXT,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.TXT("dns-version.cluster.local 28800 IN TXT 1.1.0"),
 		},
-	},
+	}},
 	// A Service (Headless) does not exist
-	{
+	{Case: test.Case{
 		Qname: "bogusendpoint.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// A Service does not exist
-	{
+	{Case: test.Case{
 		Qname: "bogusendpoint.svc0.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// AAAA Service
-	{
+	{Case: test.Case{
 		Qname: "svc6.testns.svc.cluster.local.", Qtype: dns.TypeAAAA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.AAAA("svc6.testns.svc.cluster.local.	5	IN	AAAA	1234:abcd::1"),
 		},
-	},
+	}},
 	// SRV
-	{
+	{Case: test.Case{
 		Qname: "_http._tcp.svc6.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
@@ -248,94 +281,94 @@ var dnsTestCases = []test.Case{
 		Extra: []dns.RR{
 			test.AAAA("svc6.testns.svc.cluster.local.	5	IN	AAAA	1234:abcd::1"),
 		},
-	},
+	}},
 	// AAAA Service (Headless)
-	{
+	{Case: test.Case{
 		Qname: "hdls1.testns.svc.cluster.local.", Qtype: dns.TypeAAAA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.AAAA("hdls1.testns.svc.cluster.local.	5	IN	AAAA	5678:abcd::1"),
 			test.AAAA("hdls1.testns.svc.cluster.local.	5	IN	AAAA	5678:abcd::2"),
 		},
-	},
+	}},
 	// AAAA Endpoint
-	{
+	{Case: test.Case{
 		Qname: "5678-abcd--1.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeAAAA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.AAAA("5678-abcd--1.hdls1.testns.svc.cluster.local.	5	IN	AAAA	5678:abcd::1"),
 		},
-	},
+	}},
 
-	{
+	{Case: test.Case{
 		Qname: "svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "pod.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// NS query for qname != zone (existing domain)
-	{
+	{Case: test.Case{
 		Qname: "svc.cluster.local.", Qtype: dns.TypeNS,
 		Rcode: dns.RcodeSuccess,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// NS query for qname != zone (existing domain)
-	{
+	{Case: test.Case{
 		Qname: "testns.svc.cluster.local.", Qtype: dns.TypeNS,
 		Rcode: dns.RcodeSuccess,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// NS query for qname != zone (non existing domain)
-	{
+	{Case: test.Case{
 		Qname: "foo.cluster.local.", Qtype: dns.TypeNS,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// NS query for qname != zone (non existing domain)
-	{
+	{Case: test.Case{
 		Qname: "foo.svc.cluster.local.", Qtype: dns.TypeNS,
 		Rcode: dns.RcodeNameError,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 	// Dual Stack ClusterIP Services
-	{
+	{Case: test.Case{
 		Qname: "svc-dual-stack.testns.svc.cluster.local.", Qtype: dns.TypeA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.A("svc-dual-stack.testns.svc.cluster.local.	5	IN	A	10.0.0.3"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "svc-dual-stack.testns.svc.cluster.local.", Qtype: dns.TypeAAAA,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
 			test.AAAA("svc-dual-stack.testns.svc.cluster.local.	5	IN	AAAA	10::3"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "svc-dual-stack.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{test.SRV("svc-dual-stack.testns.svc.cluster.local.	5	IN	SRV	0 50 80 svc-dual-stack.testns.svc.cluster.local.")},
@@ -343,14 +376,14 @@ var dnsTestCases = []test.Case{
 			test.A("svc-dual-stack.testns.svc.cluster.local.  5       IN      A       10.0.0.3"),
 			test.AAAA("svc-dual-stack.testns.svc.cluster.local.  5       IN      AAAA       10::3"),
 		},
-	},
-	{
+	}},
+	{Case: test.Case{
 		Qname: "svc1.testns.svc.cluster.local.", Qtype: dns.TypeSOA,
 		Rcode: dns.RcodeSuccess,
 		Ns: []dns.RR{
 			test.SOA("cluster.local.	5	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
 		},
-	},
+	}},
 }
 
 func TestServeDNS(t *testing.T) {
@@ -361,6 +394,8 @@ func TestServeDNS(t *testing.T) {
 	ctx := context.TODO()
 
 	for i, tc := range dnsTestCases {
+		k.Upstream = tc.Upstream
+
 		r := tc.Msg()
 
 		w := dnstest.NewRecorder(&test.ResponseWriter{})
@@ -379,12 +414,16 @@ func TestServeDNS(t *testing.T) {
 			t.Fatalf("Test %d, got nil message and no error for %q", i, r.Question[0].Name)
 		}
 
+		if tc.Truncated != resp.Truncated {
+			t.Errorf("Expected truncation %t, got truncation %t", tc.Truncated, resp.Truncated)
+		}
+
 		// Before sorting, make sure that CNAMES do not appear after their target records
 		if err := test.CNAMEOrder(resp); err != nil {
 			t.Errorf("Test %d, %v", i, err)
 		}
 
-		if err := test.SortAndCheck(resp, tc); err != nil {
+		if err := test.SortAndCheck(resp, tc.Case); err != nil {
 			t.Errorf("Test %d, %v", i, err)
 		}
 	}
@@ -740,3 +779,38 @@ func (APIConnServeTest) GetNamespaceByName(name string) (*object.Namespace, erro
 		Name: name,
 	}, nil
 }
+
+// Upstub implements an Upstreamer that returns a set response for test purposes
+type Upstub struct {
+	test.Case
+	Truncated bool
+	Qclass    uint16
+}
+
+// Lookup returns a set response
+func (t *Upstub) Lookup(ctx context.Context, state request.Request, name string, typ uint16) (*dns.Msg, error) {
+	var answer []dns.RR
+	// if query type is not CNAME, remove any CNAME with same name as qname from the answer
+	if t.Qtype != dns.TypeCNAME {
+		for _, a := range t.Answer {
+			if c, ok := a.(*dns.CNAME); ok && c.Header().Name == t.Qname {
+				continue
+			}
+			answer = append(answer, a)
+		}
+	} else {
+		answer = t.Answer
+	}
+
+	return &dns.Msg{
+		MsgHdr: dns.MsgHdr{
+			Response:  true,
+			Truncated: t.Truncated,
+			Rcode:     t.Rcode,
+		},
+		Question: []dns.Question{{Name: t.Qname, Qtype: t.Qtype, Qclass: t.Qclass}},
+		Answer:   answer,
+		Extra:    t.Extra,
+		Ns:       t.Ns,
+	}, nil
+}