mirror of
https://github.com/coredns/coredns.git
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697e2b4bda
* Fix truncation of messages longer than permitted by the client CoreDNS currently doesn't respect the maximum response size advertised by the client and returns the full answer on a message with the TC bit set. This breaks client implementations which rely on DNS servers respecting the advertised size limit, for example the Ruby stdlib client. It also has negative network performance implications, as large messages will be split up into multiple UDP packets, even though the client will discard the truncated response anyway. While RFC 2181 permits the response of partial RRSets, finding the correct number of records fitting into the advertised response size is non-trivial. As clients should ignore truncated messages, this change simply removes the full RRSet on truncated messages. * Remove incorrect etcd test assertion If a client requests a TXT record larger than its advertised buffer size, a DNS server should _not_ respond with the answer, but truncate the message and set the TC bit, so that the client can retry using TCP.
112 lines
2.1 KiB
Go
112 lines
2.1 KiB
Go
package request
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import (
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"fmt"
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"testing"
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"github.com/coredns/coredns/plugin/test"
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"github.com/miekg/dns"
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)
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func TestRequestDo(t *testing.T) {
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st := testRequest()
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st.Do()
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if st.do == 0 {
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t.Fatalf("Expected st.do to be set")
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}
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}
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func TestRequestRemote(t *testing.T) {
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st := testRequest()
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if st.IP() != "10.240.0.1" {
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t.Fatalf("Wrong IP from request")
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}
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p := st.Port()
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if p == "" {
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t.Fatalf("Failed to get Port from request")
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}
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if p != "40212" {
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t.Fatalf("Wrong port from request")
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}
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}
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func TestRequestMalformed(t *testing.T) {
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m := new(dns.Msg)
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st := Request{Req: m}
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if x := st.QType(); x != 0 {
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t.Errorf("Expected 0 Qtype, got %d", x)
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}
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if x := st.QClass(); x != 0 {
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t.Errorf("Expected 0 QClass, got %d", x)
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}
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if x := st.QName(); x != "." {
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t.Errorf("Expected . Qname, got %s", x)
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}
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if x := st.Name(); x != "." {
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t.Errorf("Expected . Name, got %s", x)
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}
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if x := st.Type(); x != "" {
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t.Errorf("Expected empty Type, got %s", x)
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}
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if x := st.Class(); x != "" {
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t.Errorf("Expected empty Class, got %s", x)
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}
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}
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func TestRequestScrub(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion("large.example.com.", dns.TypeSRV)
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req := Request{W: &test.ResponseWriter{}, Req: m}
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reply := new(dns.Msg)
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reply.SetReply(m)
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for i := 1; i < 200; i++ {
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reply.Answer = append(reply.Answer, test.SRV(fmt.Sprintf(
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"large.example.com. 10 IN SRV 0 0 80 10-0-0-%d.default.pod.k8s.example.com.",
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i,
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)))
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}
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msg, got := req.Scrub(reply)
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if want := ScrubDone; want != got {
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t.Errorf("want scrub result %d, got %d", want, got)
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}
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if want, got := req.Size(), msg.Len(); want < got {
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t.Errorf("want scrub to reduce message length below %d bytes, got %d bytes", want, got)
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}
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if !msg.Truncated {
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t.Errorf("want scrub to set truncated bit")
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}
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}
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func BenchmarkRequestDo(b *testing.B) {
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st := testRequest()
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for i := 0; i < b.N; i++ {
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st.Do()
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}
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}
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func BenchmarkRequestSize(b *testing.B) {
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st := testRequest()
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for i := 0; i < b.N; i++ {
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st.Size()
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}
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}
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func testRequest() Request {
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m := new(dns.Msg)
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m.SetQuestion("example.com.", dns.TypeA)
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m.SetEdns0(4097, true)
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return Request{W: &test.ResponseWriter{}, Req: m}
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}
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