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Fix NSID not being set on cached responses (#3822)

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* Add NSID to the cached responses

Signed-off-by: Erfan Besharat <erbesharat@gmail.com>

* Add test for NSID being set on cached responses

Signed-off-by: Erfan Besharat <erbesharat@gmail.com>
This commit is contained in:
Erfan Besharat 2020-04-27 20:19:56 +04:30 • committed by GitHub
parent 758f82631c
commit dcdbec53e4
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 83 additions and 4 deletions
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24
plugin/nsid/nsid.go
View file

@ -19,7 +19,8 @@ type Nsid struct {
// ResponseWriter is a response writer that adds NSID response
type ResponseWriter struct {
dns.ResponseWriter
Data string
Data string
request *dns.Msg
}
// ServeDNS implements the plugin.Handler interface.
@ -27,7 +28,7 @@ func (n Nsid) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
if option := r.IsEdns0(); option != nil {
for _, o := range option.Option {
if _, ok := o.(*dns.EDNS0_NSID); ok {
nw := &ResponseWriter{ResponseWriter: w, Data: n.Data}
nw := &ResponseWriter{ResponseWriter: w, Data: n.Data, request: r}
return plugin.NextOrFailure(n.Name(), n.Next, ctx, nw, r)
}
}
@ -37,16 +38,31 @@ func (n Nsid) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
// WriteMsg implements the dns.ResponseWriter interface.
func (w *ResponseWriter) WriteMsg(res *dns.Msg) error {
if w.request.IsEdns0() != nil && res.IsEdns0() == nil {
res.SetEdns0(w.request.IsEdns0().UDPSize(), true)
}
if option := res.IsEdns0(); option != nil {
var exists bool
for _, o := range option.Option {
if e, ok := o.(*dns.EDNS0_NSID); ok {
e.Code = dns.EDNS0NSID
e.Nsid = hex.EncodeToString([]byte(w.Data))
exists = true
}
}
// Append the NSID if it doesn't exist in EDNS0 options
if !exists {
option.Option = append(option.Option, &dns.EDNS0_NSID{
Code: dns.EDNS0NSID,
Nsid: hex.EncodeToString([]byte(w.Data)),
})
}
}
returned := w.ResponseWriter.WriteMsg(res)
return returned
return w.ResponseWriter.WriteMsg(res)
}
// Name implements the Handler interface.

63
plugin/nsid/nsid_test.go
View file

@ -6,6 +6,7 @@ import (
"testing"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/cache"
"github.com/coredns/coredns/plugin/pkg/dnstest"
"github.com/coredns/coredns/plugin/test"
"github.com/coredns/coredns/plugin/whoami"
@ -71,3 +72,65 @@ func TestNsid(t *testing.T) {
}
}
}
func TestNsidCache(t *testing.T) {
em := Nsid{
Data: "NSID",
}
c := cache.New()
tests := []struct {
next plugin.Handler
qname string
qtype uint16
expectedCode int
expectedReply string
expectedErr error
}{
{
next: whoami.Whoami{},
qname: ".",
expectedCode: dns.RcodeSuccess,
expectedReply: hex.EncodeToString([]byte("NSID")),
expectedErr: nil,
},
}
ctx := context.TODO()
for i, tc := range tests {
req := new(dns.Msg)
if tc.qtype == 0 {
tc.qtype = dns.TypeA
}
req.SetQuestion(dns.Fqdn(tc.qname), tc.qtype)
req.Question[0].Qclass = dns.ClassINET
req.SetEdns0(4096, false)
option := req.Extra[0].(*dns.OPT)
option.Option = append(option.Option, &dns.EDNS0_NSID{Code: dns.EDNS0NSID, Nsid: ""})
em.Next = tc.next
rec := dnstest.NewRecorder(&test.ResponseWriter{})
c.Next = em
code, err := c.ServeDNS(ctx, rec, req)
if err != tc.expectedErr {
t.Errorf("Test %d: Expected error %v, but got %v", i, tc.expectedErr, err)
}
if code != int(tc.expectedCode) {
t.Errorf("Test %d: Expected status code %d, but got %d", i, tc.expectedCode, code)
}
if tc.expectedReply != "" {
for _, extra := range rec.Msg.Extra {
if option, ok := extra.(*dns.OPT); ok {
e := option.Option[0].(*dns.EDNS0_NSID)
if e.Nsid != tc.expectedReply {
t.Errorf("Test %d: Expected answer %s, but got %s", i, tc.expectedReply, e.Nsid)
}
}
}
}
}
}