add integration tests for dns server

hcdns/server.go

@@ -1,4 +1,4 @@
-package dns
+package hcdns
 
 import (
 	"database/sql"
@@ -9,7 +9,7 @@ import (
 	"log"
 )
 
-const MAX_RECURSION = 10
+const MAX_RECURSION = 15
 
 func resolveInternalCNAMEs(dbConn *sql.DB, domain string, qtype uint16, maxDepth int) ([]dns.RR, error) {
 	internalCnames, err := database.FindDNSRecords(dbConn, domain, "CNAME")
@@ -21,12 +21,14 @@ func resolveInternalCNAMEs(dbConn *sql.DB, domain string, qtype uint16, maxDepth
 	for _, record := range internalCnames {
 		cname, err := dns.NewRR(fmt.Sprintf("%s %d IN CNAME %s", record.Name, record.TTL, record.Content))
 		if err != nil {
+			log.Println(err)
 			return nil, err
 		}
 		answers = append(answers, cname)
 
 		cnameRecursive, err := resolveDNS(dbConn, record.Content, qtype, maxDepth-1)
 		if err != nil {
+			log.Println(err)
 			return nil, err
 		}
 		answers = append(answers, cnameRecursive...)
@@ -62,11 +64,7 @@ func resolveDNS(dbConn *sql.DB, domain string, qtype uint16, maxDepth int) ([]dn
 		return nil, err
 	}
 
-	if len(answers) > 0 {
 	return answers, nil
-	}
-
-	return nil, fmt.Errorf("no records found for %s", domain)
 }
 
 type DnsHandler struct {
@@ -83,7 +81,9 @@ func (h *DnsHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 		answers, err := resolveDNS(h.DbConn, question.Name, question.Qtype, MAX_RECURSION)
 		if err != nil {
 			fmt.Println(err)
-			continue
+			msg.SetRcode(r, dns.RcodeServerFailure)
+			w.WriteMsg(msg)
+			return
 		}
 		msg.Answer = append(msg.Answer, answers...)
 	}
@@ -98,7 +98,6 @@ func (h *DnsHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 
 func MakeServer(argv *args.Arguments, dbConn *sql.DB) *dns.Server {
 	handler := &DnsHandler{
-		DnsResolvers: argv.DnsRecursion,
 		DbConn: dbConn,
 	}
 	addr := fmt.Sprintf(":%d", argv.DnsPort)

main.go

@@ -6,7 +6,7 @@ import (
 	"git.hatecomputers.club/hatecomputers/hatecomputers.club/api"
 	"git.hatecomputers.club/hatecomputers/hatecomputers.club/args"
 	"git.hatecomputers.club/hatecomputers/hatecomputers.club/database"
-	"git.hatecomputers.club/hatecomputers/hatecomputers.club/dns"
+	"git.hatecomputers.club/hatecomputers/hatecomputers.club/hcdns"
 	"git.hatecomputers.club/hatecomputers/hatecomputers.club/scheduler"
 	"github.com/joho/godotenv"
 )
@@ -52,7 +52,7 @@ func main() {
 	}
 
 	if argv.Dns {
-		server := dns.MakeServer(argv, dbConn)
+		server := hcdns.MakeServer(argv, dbConn)
 		log.Println("🚀🚀 DNS resolver listening on port", argv.DnsPort)
 		go func() {
 			err = server.ListenAndServe()

test/dns_test.go

@@ -0,0 +1,244 @@
+package hcdns
+
+import (
+	"database/sql"
+	"os"
+	"sync"
+	"testing"
+
+	"git.hatecomputers.club/hatecomputers/hatecomputers.club/args"
+	"git.hatecomputers.club/hatecomputers/hatecomputers.club/database"
+	"git.hatecomputers.club/hatecomputers/hatecomputers.club/hcdns"
+	"github.com/miekg/dns"
+)
+
+const (
+	testDBPath = "test.db"
+	address    = "127.0.0.1:8353"
+	dnsPort    = 8353
+)
+
+func setup(dbPath string) (*sql.DB, *dns.Server, *sync.WaitGroup) {
+	testDb := database.MakeConn(&dbPath)
+	database.Migrate(testDb)
+	testUser := &database.User{
+		ID: "test",
+	}
+	database.FindOrSaveUser(testDb, testUser)
+
+	server := hcdns.MakeServer(&args.Arguments{
+		DnsPort: dnsPort,
+	}, testDb)
+
+	waitGroup := sync.WaitGroup{}
+	waitGroup.Add(1)
+	go func() {
+		server.ListenAndServe()
+		waitGroup.Done()
+	}()
+
+	return testDb, server, &waitGroup
+}
+
+func destroy(conn *sql.DB, path string) {
+	conn.Close()
+	os.Remove(path)
+}
+
+func TestWhenCNAMEIsResolved(t *testing.T) {
+	t.Log("TestWhenCNAMEIsResolved")
+
+	testDb, server, _ := setup(testDBPath)
+	defer destroy(testDb, testDBPath)
+	defer server.Shutdown()
+
+	cname := &database.DNSRecord{
+		ID:       "1",
+		UserID:   "test",
+		Name:     "cname.internal.example.com.",
+		Type:     "CNAME",
+		Content:  "res.example.com.",
+		TTL:      300,
+		Internal: true,
+	}
+	a := &database.DNSRecord{
+		ID:       "2",
+		UserID:   "test",
+		Name:     "res.example.com.",
+		Type:     "A",
+		Content:  "127.0.0.1",
+		TTL:      300,
+		Internal: true,
+	}
+	database.SaveDNSRecord(testDb, cname)
+	database.SaveDNSRecord(testDb, a)
+
+	qtype := dns.TypeA
+	domain := dns.Fqdn(cname.Name)
+	client := new(dns.Client)
+	message := new(dns.Msg)
+	message.SetQuestion(domain, qtype)
+
+	in, _, err := client.Exchange(message, address)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(in.Answer) != 2 {
+		t.Fatalf("expected 2 answers, got %d", len(in.Answer))
+	}
+
+	if in.Answer[0].Header().Name != cname.Name {
+		t.Fatalf("expected cname.internal.example.com., got %s", in.Answer[0].Header().Name)
+	}
+
+	if in.Answer[1].Header().Name != a.Name {
+		t.Fatalf("expected res.example.com., got %s", in.Answer[1].Header().Name)
+	}
+
+	if in.Answer[0].(*dns.CNAME).Target != a.Name {
+		t.Fatalf("expected res.example.com., got %s", in.Answer[0].(*dns.CNAME).Target)
+	}
+
+	if in.Answer[1].(*dns.A).A.String() != a.Content {
+		t.Fatalf("expected %s, got %s", a.Content, in.Answer[1].(*dns.A).A.String())
+	}
+
+	if in.Answer[0].Header().Rrtype != dns.TypeCNAME {
+		t.Fatalf("expected CNAME, got %d", in.Answer[0].Header().Rrtype)
+	}
+
+	if in.Answer[1].Header().Rrtype != dns.TypeA {
+		t.Fatalf("expected A, got %d", in.Answer[1].Header().Rrtype)
+	}
+
+	if int(in.Answer[0].Header().Ttl) != cname.TTL {
+		t.Fatalf("expected %d, got %d", cname.TTL, in.Answer[0].Header().Ttl)
+	}
+
+	if !in.Authoritative {
+		t.Fatalf("expected authoritative response")
+	}
+}
+
+func TestWhenNoRecordNxDomain(t *testing.T) {
+	t.Log("TestWhenNoRecordNxDomain")
+
+	testDb, server, _ := setup(testDBPath)
+	defer destroy(testDb, testDBPath)
+	defer server.Shutdown()
+
+	qtype := dns.TypeA
+	domain := dns.Fqdn("nonexistant.example.com.")
+	client := new(dns.Client)
+	message := new(dns.Msg)
+	message.SetQuestion(domain, qtype)
+
+	in, _, err := client.Exchange(message, address)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(in.Answer) != 0 {
+		t.Fatalf("expected 0 answers, got %d", len(in.Answer))
+	}
+
+	if in.Rcode != dns.RcodeNameError {
+		t.Fatalf("expected NXDOMAIN, got %d", in.Rcode)
+	}
+}
+
+func TestWhenUnresolvingCNAME(t *testing.T) {
+	t.Log("TestWhenUnresolvingCNAME")
+
+	testDb, server, _ := setup(testDBPath)
+	defer destroy(testDb, testDBPath)
+	defer server.Shutdown()
+
+	cname := &database.DNSRecord{
+		ID:       "1",
+		UserID:   "test",
+		Name:     "cname.internal.example.com.",
+		Type:     "CNAME",
+		Content:  "nonexistant.example.com.",
+		TTL:      300,
+		Internal: true,
+	}
+	database.SaveDNSRecord(testDb, cname)
+
+	qtype := dns.TypeA
+	domain := dns.Fqdn(cname.Name)
+	client := new(dns.Client)
+	message := new(dns.Msg)
+	message.SetQuestion(domain, qtype)
+
+	in, _, err := client.Exchange(message, address)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(in.Answer) != 1 {
+		t.Fatalf("expected 1 answer, got %d", len(in.Answer))
+	}
+
+	if !in.Authoritative {
+		t.Fatalf("expected authoritative response")
+	}
+
+	if in.Answer[0].Header().Name != cname.Name {
+		t.Fatalf("expected cname.internal.example.com., got %s", in.Answer[0].Header().Name)
+	}
+
+	if in.Answer[0].Header().Rrtype != dns.TypeCNAME {
+		t.Fatalf("expected CNAME, got %d", in.Answer[0].Header().Rrtype)
+	}
+
+	if in.Answer[0].(*dns.CNAME).Target != cname.Content {
+		t.Fatalf("expected nonexistant.example.com., got %s", in.Answer[0].(*dns.CNAME).Target)
+	}
+
+	if in.Rcode == dns.RcodeNameError {
+		t.Fatalf("expected no NXDOMAIN, got %d", in.Rcode)
+	}
+}
+
+func TestWhenUnresolvingCNAMEWithMaxDepth(t *testing.T) {
+	t.Log("TestWhenUnresolvingCNAMEWithMaxDepth")
+
+	testDb, server, _ := setup(testDBPath)
+	defer destroy(testDb, testDBPath)
+	defer server.Shutdown()
+
+	cname := &database.DNSRecord{
+		ID:       "1",
+		UserID:   "test",
+		Name:     "cname.internal.example.com.",
+		Type:     "CNAME",
+		Content:  "cname.internal.example.com.",
+		TTL:      300,
+		Internal: true,
+	}
+	database.SaveDNSRecord(testDb, cname)
+
+	qtype := dns.TypeA
+	domain := dns.Fqdn(cname.Name)
+	client := new(dns.Client)
+	message := new(dns.Msg)
+	message.SetQuestion(domain, qtype)
+
+	in, _, err := client.Exchange(message, address)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(in.Answer) > 0 {
+		t.Fatalf("expected 0 answers, got %d", len(in.Answer))
+	}
+	if in.Rcode != dns.RcodeServerFailure {
+		t.Fatalf("expected SERVFAIL, got %d", in.Rcode)
+	}
+}