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package resolver
import (
"context"
"net"
"testing"
"time"
"github.com/miekg/dns"
)
func startTestServer(t *testing.T, addr string, handler dns.Handler) *dns.Server {
t.Helper()
srv := &dns.Server{
Addr: addr,
Net: "udp",
Handler: handler,
UDPSize: 4096,
}
go func() {
if err := srv.ListenAndServe(); err != nil {
}
}()
return srv
}
func TestLookupDirectAnswer(t *testing.T) {
mux := dns.NewServeMux()
mux.HandleFunc(".", func(w dns.ResponseWriter, req *dns.Msg) {
resp := new(dns.Msg)
resp.SetReply(req)
resp.Authoritative = true
if req.Question[0].Name == "example.com." &&
req.Question[0].Qtype == dns.TypeA {
resp.Answer = append(resp.Answer, &dns.A{
Hdr: dns.RR_Header{
Name: "example.com.",
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: 60,
},
A: net.IPv4(127, 0, 0, 1),
})
} else {
resp.Rcode = dns.RcodeNameError
}
w.WriteMsg(resp)
})
srv := startTestServer(t, "127.0.0.1:15353", mux)
defer srv.Shutdown()
time.Sleep(50 * time.Millisecond)
r := New(
WithRootAddresses([]string{"127.0.0.1:15353"}),
WithTimeout(500*time.Millisecond),
)
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
resp, err := r.Lookup(ctx, "example.com.", dns.TypeA)
if err != nil {
t.Fatalf("Lookup failed: %v", err)
}
if resp.Rcode != dns.RcodeSuccess {
t.Fatalf("expected NOERROR, got %d (%s)",
resp.Rcode, dns.RcodeToString[resp.Rcode])
}
if len(resp.Answer) != 1 {
t.Fatalf("expected 1 answer, got %d", len(resp.Answer))
}
a, ok := resp.Answer[0].(*dns.A)
if !ok {
t.Fatal("expected A record")
}
if !a.A.Equal(net.IPv4(127, 0, 0, 1)) {
t.Fatalf("expected 127.0.0.1, got %s", a.A)
}
}
func TestLookupNXDOMAIN(t *testing.T) {
mux := dns.NewServeMux()
mux.HandleFunc(".", func(w dns.ResponseWriter, req *dns.Msg) {
resp := new(dns.Msg)
resp.SetReply(req)
resp.Rcode = dns.RcodeNameError
w.WriteMsg(resp)
})
srv := startTestServer(t, "127.0.0.1:15354", mux)
defer srv.Shutdown()
time.Sleep(50 * time.Millisecond)
r := New(
WithRootAddresses([]string{"127.0.0.1:15354"}),
WithTimeout(500*time.Millisecond),
)
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
resp, err := r.Lookup(ctx, "nonexistent.xyz.", dns.TypeA)
if err != nil {
t.Fatalf("Lookup failed: %v", err)
}
if resp.Rcode != dns.RcodeNameError {
t.Fatalf("expected NXDOMAIN, got %d", resp.Rcode)
}
}
func TestNextServersWithGlue(t *testing.T) {
msg := new(dns.Msg)
msg.Authoritative = false
msg.Ns = append(msg.Ns, &dns.NS{
Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeNS, Ttl: 300},
Ns: "ns1.example.com.",
})
msg.Extra = append(msg.Extra, &dns.A{
Hdr: dns.RR_Header{Name: "ns1.example.com.", Rrtype: dns.TypeA, Ttl: 300},
A: net.ParseIP("192.0.2.1").To4(),
})
msg.Extra = append(msg.Extra, &dns.AAAA{
Hdr: dns.RR_Header{Name: "ns1.example.com.", Rrtype: dns.TypeAAAA, Ttl: 300},
AAAA: net.ParseIP("2001:db8::1"),
})
r := &Resolver{}
addrs, err := r.nextServers(context.Background(), msg)
if err != nil {
t.Fatalf("nextServers failed: %v", err)
}
if len(addrs) != 1 || addrs[0] != "192.0.2.1" {
t.Fatalf("expected [192.0.2.1], got %v", addrs)
}
}
func TestNextServersNoGlue(t *testing.T) {
msg := new(dns.Msg)
msg.Authoritative = false
msg.Ns = append(msg.Ns, &dns.NS{
Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeNS, Ttl: 300},
Ns: "ns1.example.com.",
})
r := &Resolver{maxDelegations: 30, timeout: time.Second, retries: 1}
_, err := r.nextServers(context.Background(), msg)
if err == nil {
t.Fatal("expected error when no glue and no roots")
}
}
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