Add bufsize plugin for preparing the DNS Flag Day and avoiding IP fragmentation (#3401)

* add bufsize plugin Signed-off-by: ykhr53 <yukihira.lab@gmail.com> * add docstring and comment Signed-off-by: ykhr53 <yukihira.lab@gmail.com> * delete stdout messages when get an error Signed-off-by: ykhr53 <yukihira.lab@gmail.com> * change to context.Background from TODO Signed-off-by: ykhr53 <yukihira.lab@gmail.com> * define default bufsize as defaultBufSize constant Signed-off-by: ykhr53 <yukihira.lab@gmail.com> * fix some comments Signed-off-by: ykhr53 <yukihira.lab@gmail.com> * function name change: parse Signed-off-by: ykhr53 <yukihira.lab@gmail.com> * function name change: parse Signed-off-by: ykhr53 <yukihira.lab@gmail.com>
2019-11-10 08:10:12 +00:00 · 2019-11-10 08:10:12 +00:00 · e23a34abb4
commit e23a34abb4
parent 113783ed91
8 changed files with 234 additions and 0 deletions
--- a/plugin/bufsize/bufsize_test.go
+++ b/plugin/bufsize/bufsize_test.go
@ -0,0 +1,72 @@
+package bufsize
+
+import (
+	"context"
+	"testing"
+
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/test"
+	"github.com/coredns/coredns/plugin/whoami"
+
+	"github.com/miekg/dns"
+)
+
+func TestBufsize(t *testing.T) {
+	em := Bufsize{
+		Size: 512,
+	}
+
+	tests := []struct {
+		next            plugin.Handler
+		qname           string
+		inputBufsize    uint16
+		outgoingBufsize uint16
+		expectedErr     error
+	}{
+		// This plugin is responsible for limiting outgoing query's bufize
+		{
+			next:            whoami.Whoami{},
+			qname:           ".",
+			inputBufsize:    1200,
+			outgoingBufsize: 512,
+			expectedErr:     nil,
+		},
+		// If EDNS is not enabled, this plugin adds it
+		{
+			next:            whoami.Whoami{},
+			qname:           ".",
+			outgoingBufsize: 512,
+			expectedErr:     nil,
+		},
+	}
+
+	for i, tc := range tests {
+		req := new(dns.Msg)
+		req.SetQuestion(dns.Fqdn(tc.qname), dns.TypeA)
+		req.Question[0].Qclass = dns.ClassINET
+		em.Next = tc.next
+
+		if tc.inputBufsize != 0 {
+			req.SetEdns0(tc.inputBufsize, false)
+		}
+
+		_, err := em.ServeDNS(context.Background(), &test.ResponseWriter{}, req)
+
+		if err != tc.expectedErr {
+			t.Errorf("Test %d: Expected error is %v, but got %v", i, tc.expectedErr, err)
+		}
+
+		if tc.outgoingBufsize != 0 {
+			for _, extra := range req.Extra {
+				if option, ok := extra.(*dns.OPT); ok {
+					b := option.UDPSize()
+					if b != tc.outgoingBufsize {
+						t.Errorf("Test %d: Expected outgoing bufsize is %d, but got %d", i, tc.outgoingBufsize, b)
+					}
+				} else {
+					t.Errorf("Test %d: Not found OPT RR.", i)
+				}
+			}
+		}
+	}
+}