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package server
import (
"log/slog"
"context"
"testing"
"time"
"github.com/miekg/dns"
"linum/internal/resolver"
)
func testServer(t *testing.T) *Server {
t.Helper()
r := resolver.New(
resolver.WithRootAddresses([]string{"127.0.0.1:1"}),
resolver.WithTimeout(50*time.Millisecond),
)
baseCtx, cancel := context.WithCancel(context.Background())
t.Cleanup(cancel)
return &Server{logger: slog.Default(), resolver: r, baseCtx: baseCtx}
}
func TestBuildResponse(t *testing.T) {
s := testServer(t)
tests := []struct {
name string
req *dns.Msg
wantRcode int
wantAnswers int
wantEdns0 bool
}{
{
name: "no questions returns FORMERR",
req: func() *dns.Msg {
return new(dns.Msg)
}(),
wantRcode: dns.RcodeFormatError,
wantAnswers: 0,
wantEdns0: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
resp, _ := s.buildResponse(tt.req)
if resp.Rcode != tt.wantRcode {
t.Errorf("rcode: got %d, want %d", resp.Rcode, tt.wantRcode)
}
if len(resp.Answer) != tt.wantAnswers {
t.Errorf("answers: got %d, want %d", len(resp.Answer), tt.wantAnswers)
}
if tt.wantEdns0 {
if opt := resp.IsEdns0(); opt == nil {
t.Error("expected EDNS0 in response, got none")
} else if opt.UDPSize() != 4096 {
t.Errorf("edns0 udp size: got %d, want 4096", opt.UDPSize())
}
}
})
}
}
func TestBuildResponseWithQuery(t *testing.T) {
s := testServer(t)
// Valid query → must not panic, rcode must be valid
m := new(dns.Msg)
m.SetQuestion("example.com.", dns.TypeA)
resp, _ := s.buildResponse(m)
if resp == nil {
t.Fatal("buildResponse returned nil")
}
if resp.Rcode != dns.RcodeSuccess && resp.Rcode != dns.RcodeServerFailure {
t.Errorf("expected success or server failure, got %d", resp.Rcode)
}
}
func FuzzBuildResponse(f *testing.F) {
baseCtx, cancel := context.WithCancel(context.Background())
defer cancel()
s := &Server{logger: slog.Default(), baseCtx: baseCtx}
// For fuzz, use a resolver that won't make real network calls
s.resolver = resolver.New(
resolver.WithRootAddresses([]string{"127.0.0.1:1"}),
resolver.WithTimeout(10*time.Millisecond),
)
seed := []byte{
0x00, 0x00, // ID
0x01, 0x00, // flags: RD
0x00, 0x01, // QDCOUNT: 1
0x00, 0x00, // ANCOUNT
0x00, 0x00, // NSCOUNT
0x00, 0x00, // ARCOUNT
// Question: example.com A
0x07, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65,
0x03, 0x63, 0x6f, 0x6d,
0x00,
0x00, 0x01, // QTYPE: A
0x00, 0x01, // QCLASS: IN
}
f.Add(seed)
f.Fuzz(func(t *testing.T, data []byte) {
msg := new(dns.Msg)
if err := msg.Unpack(data); err != nil {
return
}
resp, _ := s.buildResponse(msg)
if resp == nil {
t.Fatal("buildResponse returned nil")
}
if _, err := resp.Pack(); err != nil {
t.Errorf("pack failed: %v", err)
}
})
}
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