dns recursive resolver(iterative, root hints, delegfation, glue, fallback), adblocker, dns cache

1 files changed, 140 insertions, 0 deletions

diff --git a/internal/cache/cache_test.go b/internal/cache/cache_test.go
new file mode 100644
index 0000000..6556dcb
--- /dev/null
+++ b/internal/cache/cache_test.go
@@ -0,0 +1,140 @@
+package cache
+
+import (
+	"fmt"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/miekg/dns"
+)
+
+func TestSetGet(t *testing.T) {
+	c, err := NewCache(100, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Stop()
+
+	msg := new(dns.Msg)
+	msg.Answer = append(msg.Answer, &dns.A{
+		Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeA, Ttl:300},
+		A: net.IPv4(1,2,3,4),
+	})
+
+	key := Key{Name: "example.com.", Qtype: dns.TypeA, Class: dns.ClassINET}
+	c.Set(key, msg, 300*time.Second)
+
+	got, ok := c.Get(key)
+	if !ok {
+		t.Fatal("expected cache hit")
+	}
+	if len(got.Answer) != 1 {
+		t.Fatalf("expected 1 answer, got %d", len(got.Answer))
+	}
+	a, _ := got.Answer[0].(*dns.A)
+	if !a.A.Equal(net.IPv4(1,2,3,4)) {
+		t.Errorf("IP = %s, want 1.2.3.4", a.A)
+	}
+}
+
+func TestExpiry(t *testing.T) {
+	c, _ := NewCache(10, "")
+	defer c.Stop()
+	msg := new(dns.Msg)
+	key := Key{Name: "x.com.", Qtype: dns.TypeA, Class: dns.ClassINET}
+	c.Set(key, msg, 30*time.Millisecond)
+	time.Sleep(60 * time.Millisecond)
+	_, ok := c.Get(key)
+	if ok {
+		t.Fatal("expected miss after expiry")
+	}
+}
+
+func TestEviction(t *testing.T) {
+	c, _ := NewCache(2, "")
+	defer c.Stop()
+	for i := 0; i < 5; i++ {
+		name := fmt.Sprintf("d%d.com.", i)
+		msg := new(dns.Msg)
+		c.Set(Key{Name: name, Qtype: dns.TypeA, Class: dns.ClassINET}, msg, 60*time.Second)
+	}
+	if c.Len() > 2 {
+		t.Errorf("expected ≤2 entries, got %d", c.Len())
+	}
+}
+
+func TestComputeTTL(t *testing.T) {
+	msg := new(dns.Msg)
+	msg.Answer = append(msg.Answer, &dns.A{
+		Hdr: dns.RR_Header{Name: "x.", Rrtype: dns.TypeA, Ttl: 120},
+	})
+	if d := computeTTL(msg); d != 120*time.Second {
+		t.Errorf("TTL = %v, want 120s", d)
+	}
+}
+
+func TestNegativeTTL(t *testing.T) {
+	msg := new(dns.Msg)
+	msg.Rcode = dns.RcodeNameError
+	msg.Ns = append(msg.Ns, &dns.SOA{
+		Hdr:   dns.RR_Header{Name: "com.", Rrtype: dns.TypeSOA, Ttl: 900},
+		Minttl: 300,
+	})
+	if d := computeTTL(msg); d != 300*time.Second {
+		t.Errorf("negative TTL = %v, want 300s", d)
+	}
+}
+
+func TestRace(t *testing.T) {
+	c, _ := NewCache(1000, "")
+	defer c.Stop()
+	done := make(chan struct{})
+	go func() {
+		for i := 0; i < 100; i++ {
+			msg := new(dns.Msg)
+			c.Set(Key{Name: fmt.Sprintf("d%d.com.", i), Qtype: dns.TypeA, Class: dns.ClassINET}, msg, time.Second)
+		}
+		close(done)
+	}()
+	for i := 0; i < 100; i++ {
+		c.Get(Key{Name: fmt.Sprintf("d%d.com.", i), Qtype: dns.TypeA, Class: dns.ClassINET})
+	}
+	<-done
+	c.Stats()
+	c.Len()
+}
+
+func TestSQLitePersistence(t *testing.T) {
+	dir := t.TempDir()
+	dbPath := dir + "/cache.db"
+
+	c, err := NewCache(100, dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	msg := new(dns.Msg)
+	msg.Answer = append(msg.Answer, &dns.A{
+		Hdr: dns.RR_Header{Name: "x.com.", Rrtype: dns.TypeA, Ttl: 300},
+		A:   net.IPv4(1, 2, 3, 4),
+	})
+	key := Key{Name: "x.com.", Qtype: dns.TypeA, Class: dns.ClassINET}
+	c.Set(key, msg, 300*time.Second)
+	c.Stop()
+
+	c2, err := NewCache(100, dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c2.Stop()
+
+	got, ok := c2.Get(key)
+	if !ok {
+		t.Fatal("expected cache hit from SQLite load")
+	}
+	a, _ := got.Answer[0].(*dns.A)
+	if !a.A.Equal(net.IPv4(1, 2, 3, 4)) {
+		t.Errorf("IP = %s, want 1.2.3.4", a.A)
+	}
+}