diff options
| -rw-r--r-- | request/request.go | 16 | ||||
| -rw-r--r-- | request/request_test.go | 55 |
2 files changed, 63 insertions, 8 deletions
diff --git a/request/request.go b/request/request.go index 06f840f89..3ee4c2126 100644 --- a/request/request.go +++ b/request/request.go @@ -263,12 +263,16 @@ func (r *Request) Scrub(reply *dns.Msg) (*dns.Msg, Result) { // Account for the OPT record that gets added in SizeAndDo(), subtract that length. sub := 0 - if r.Do() { + if r.Req.IsEdns0() != nil { sub = optLen } - origExtra := reply.Extra + + // substract to make spaces for re-added EDNS0 OPT RR. re := len(reply.Extra) - sub + size -= sub + l, m := 0, 0 + origExtra := reply.Extra for l < re { m = (l + re) / 2 reply.Extra = origExtra[:m] @@ -297,9 +301,9 @@ func (r *Request) Scrub(reply *dns.Msg) (*dns.Msg, Result) { return reply, ScrubExtra } - origAnswer := reply.Answer ra := len(reply.Answer) l, m = 0, 0 + origAnswer := reply.Answer for l < ra { m = (l + ra) / 2 reply.Answer = origAnswer[:m] @@ -324,14 +328,12 @@ func (r *Request) Scrub(reply *dns.Msg) (*dns.Msg, Result) { // this extra m-1 step does make it fit in the client's buffer however. } - // It now fits, but Truncated. We can't call sizeAndDo() because that adds a new record (OPT) - // in the additional section. + r.SizeAndDo(reply) reply.Truncated = true return reply, ScrubAnswer } -// Type returns the type of the question as a string. If the request is malformed -// the empty string is returned. +// Type returns the type of the question as a string. If the request is malformed the empty string is returned. func (r *Request) Type() string { if r.Req == nil { return "" diff --git a/request/request_test.go b/request/request_test.go index c58612605..cad2dce0d 100644 --- a/request/request_test.go +++ b/request/request_test.go @@ -138,6 +138,39 @@ func TestRequestScrubExtraEdns0(t *testing.T) { } } +func TestRequestScrubExtraRegression(t *testing.T) { + m := new(dns.Msg) + m.SetQuestion("large.example.com.", dns.TypeSRV) + m.SetEdns0(2048, true) + req := Request{W: &test.ResponseWriter{}, Req: m} + + reply := new(dns.Msg) + reply.SetReply(m) + for i := 1; i < 33; i++ { + reply.Answer = append(reply.Answer, test.SRV( + fmt.Sprintf("large.example.com. 10 IN SRV 0 0 80 10-0-0-%d.default.pod.k8s.example.com.", i))) + } + for i := 1; i < 33; i++ { + reply.Extra = append(reply.Extra, test.A( + fmt.Sprintf("10-0-0-%d.default.pod.k8s.example.com. 10 IN A 10.0.0.%d", i, i))) + } + + _, got := req.Scrub(reply) + if want := ScrubExtra; want != got { + t.Errorf("Want scrub result %d, got %d", want, got) + } + if want, got := req.Size(), reply.Len(); want < got { + t.Errorf("Want scrub to reduce message length below %d bytes, got %d bytes", want, got) + } + if reply.Truncated { + t.Errorf("Want scrub to not set truncated bit") + } + opt := reply.Extra[len(reply.Extra)-1] + if opt.Header().Rrtype != dns.TypeOPT { + t.Errorf("Last RR must be OPT record") + } +} + func TestRequestScrubAnswerExact(t *testing.T) { m := new(dns.Msg) m.SetQuestion("large.example.com.", dns.TypeSRV) @@ -196,10 +229,30 @@ func BenchmarkRequestSize(b *testing.B) { } } +func BenchmarkRequestScrub(b *testing.B) { + st := testRequest() + + reply := new(dns.Msg) + reply.SetReply(st.Req) + for i := 1; i < 33; i++ { + reply.Answer = append(reply.Answer, test.SRV( + fmt.Sprintf("large.example.com. 10 IN SRV 0 0 80 10-0-0-%d.default.pod.k8s.example.com.", i))) + } + for i := 1; i < 33; i++ { + reply.Extra = append(reply.Extra, test.A( + fmt.Sprintf("10-0-0-%d.default.pod.k8s.example.com. 10 IN A 10.0.0.%d", i, i))) + } + + b.ResetTimer() + for i := 0; i < b.N; i++ { + st.Scrub(reply.Copy()) + } +} + func testRequest() Request { m := new(dns.Msg) m.SetQuestion("example.com.", dns.TypeA) - m.SetEdns0(4097, true) + m.SetEdns0(4096, true) return Request{W: &test.ResponseWriter{}, Req: m} } |