Revert "DNS: fix typo & refine code (#1183)"

This reverts commit 73470e8dd8d020f3f19d77545cce00a9dbb96c2e.

app/dns/nameserver_doh.go

@@ -33,7 +33,7 @@ import (
 // thus most of the DOH implementation is copied from udpns.go
 type DoHNameServer struct {
 	sync.RWMutex
-	ips        map[string]*record
+	ips        map[string]record
 	pub        *pubsub.Service
 	cleanup    *task.Periodic
 	reqID      uint32
@@ -113,7 +113,7 @@ func NewDoHLocalNameServer(url *url.URL) *DoHNameServer {
 
 func baseDOHNameServer(url *url.URL, prefix string) *DoHNameServer {
 	s := &DoHNameServer{
-		ips:    make(map[string]*record),
+		ips:    make(map[string]record),
 		pub:    pubsub.NewService(),
 		name:   prefix + "//" + url.Host,
 		dohURL: url.String(),
@@ -157,7 +157,7 @@ func (s *DoHNameServer) Cleanup() error {
 	}
 
 	if len(s.ips) == 0 {
-		s.ips = make(map[string]*record)
+		s.ips = make(map[string]record)
 	}
 
 	return nil
@@ -167,10 +167,7 @@ func (s *DoHNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
 	elapsed := time.Since(req.start)
 
 	s.Lock()
-	rec, found := s.ips[req.domain]
-	if !found {
-		rec = &record{}
-	}
+	rec := s.ips[req.domain]
 	updated := false
 
 	switch req.reqType {
@@ -180,7 +177,7 @@ func (s *DoHNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
 			updated = true
 		}
 	case dnsmessage.TypeAAAA:
-		addr := make([]net.Address, 0, len(ipRec.IP))
+		addr := make([]net.Address, 0)
 		for _, ip := range ipRec.IP {
 			if len(ip.IP()) == net.IPv6len {
 				addr = append(addr, ip)
@@ -299,30 +296,34 @@ func (s *DoHNameServer) findIPsForDomain(domain string, option dns_feature.IPOpt
 		return nil, errRecordNotFound
 	}
 
-	var err4 error
-	var err6 error
 	var ips []net.Address
-	var ip6 []net.Address
-
-	switch {
-	case option.IPv4Enable:
-		ips, err4 = record.A.getIPs()
-		fallthrough
-	case option.IPv6Enable:
-		ip6, err6 = record.AAAA.getIPs()
-		ips = append(ips, ip6...)
+	var lastErr error
+	if option.IPv6Enable && record.AAAA != nil && record.AAAA.RCode == dnsmessage.RCodeSuccess {
+		aaaa, err := record.AAAA.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, aaaa...)
+	}
+
+	if option.IPv4Enable && record.A != nil && record.A.RCode == dnsmessage.RCodeSuccess {
+		a, err := record.A.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, a...)
 	}
 
 	if len(ips) > 0 {
 		return toNetIP(ips)
 	}
 
-	if err4 != nil {
-		return nil, err4
+	if lastErr != nil {
+		return nil, lastErr
 	}
 
-	if err6 != nil {
-		return nil, err6
+	if (option.IPv4Enable && record.A != nil) || (option.IPv6Enable && record.AAAA != nil) {
+		return nil, dns_feature.ErrEmptyResponse
 	}
 
 	return nil, errRecordNotFound

app/dns/nameserver_quic.go

@@ -31,12 +31,12 @@ const handshakeIdleTimeout = time.Second * 8
 // QUICNameServer implemented DNS over QUIC
 type QUICNameServer struct {
 	sync.RWMutex
-	ips         map[string]*record
+	ips         map[string]record
 	pub         *pubsub.Service
 	cleanup     *task.Periodic
 	reqID       uint32
 	name        string
-	destination *net.Destination
+	destination net.Destination
 	session     quic.Session
 }
 
@@ -55,10 +55,10 @@ func NewQUICNameServer(url *url.URL) (*QUICNameServer, error) {
 	dest := net.UDPDestination(net.ParseAddress(url.Hostname()), port)
 
 	s := &QUICNameServer{
-		ips:         make(map[string]*record),
+		ips:         make(map[string]record),
 		pub:         pubsub.NewService(),
 		name:        url.String(),
-		destination: &dest,
+		destination: dest,
 	}
 	s.cleanup = &task.Periodic{
 		Interval: time.Minute,
@@ -100,7 +100,7 @@ func (s *QUICNameServer) Cleanup() error {
 	}
 
 	if len(s.ips) == 0 {
-		s.ips = make(map[string]*record)
+		s.ips = make(map[string]record)
 	}
 
 	return nil
@@ -110,10 +110,7 @@ func (s *QUICNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
 	elapsed := time.Since(req.start)
 
 	s.Lock()
-	rec, found := s.ips[req.domain]
-	if !found {
-		rec = &record{}
-	}
+	rec := s.ips[req.domain]
 	updated := false
 
 	switch req.reqType {
@@ -233,30 +230,34 @@ func (s *QUICNameServer) findIPsForDomain(domain string, option dns_feature.IPOp
 		return nil, errRecordNotFound
 	}
 
-	var err4 error
-	var err6 error
 	var ips []net.Address
-	var ip6 []net.Address
-
-	switch {
-	case option.IPv4Enable:
-		ips, err4 = record.A.getIPs()
-		fallthrough
-	case option.IPv6Enable:
-		ip6, err6 = record.AAAA.getIPs()
-		ips = append(ips, ip6...)
+	var lastErr error
+	if option.IPv6Enable && record.AAAA != nil && record.AAAA.RCode == dnsmessage.RCodeSuccess {
+		aaaa, err := record.AAAA.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, aaaa...)
+	}
+
+	if option.IPv4Enable && record.A != nil && record.A.RCode == dnsmessage.RCodeSuccess {
+		a, err := record.A.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, a...)
 	}
 
 	if len(ips) > 0 {
 		return toNetIP(ips)
 	}
 
-	if err4 != nil {
-		return nil, err4
+	if lastErr != nil {
+		return nil, lastErr
 	}
 
-	if err6 != nil {
-		return nil, err6
+	if (option.IPv4Enable && record.A != nil) || (option.IPv6Enable && record.AAAA != nil) {
+		return nil, dns_feature.ErrEmptyResponse
 	}
 
 	return nil, errRecordNotFound

app/dns/nameserver_tcp.go

@@ -30,8 +30,8 @@ import (
 type TCPNameServer struct {
 	sync.RWMutex
 	name        string
-	destination *net.Destination
-	ips         map[string]*record
+	destination net.Destination
+	ips         map[string]record
 	pub         *pubsub.Service
 	cleanup     *task.Periodic
 	reqID       uint32
@@ -46,7 +46,7 @@ func NewTCPNameServer(url *url.URL, dispatcher routing.Dispatcher) (*TCPNameServ
 	}
 
 	s.dial = func(ctx context.Context) (net.Conn, error) {
-		link, err := dispatcher.Dispatch(ctx, *s.destination)
+		link, err := dispatcher.Dispatch(ctx, s.destination)
 		if err != nil {
 			return nil, err
 		}
@@ -68,7 +68,7 @@ func NewTCPLocalNameServer(url *url.URL) (*TCPNameServer, error) {
 	}
 
 	s.dial = func(ctx context.Context) (net.Conn, error) {
-		return internet.DialSystem(ctx, *s.destination, nil)
+		return internet.DialSystem(ctx, s.destination, nil)
 	}
 
 	return s, nil
@@ -86,8 +86,8 @@ func baseTCPNameServer(url *url.URL, prefix string) (*TCPNameServer, error) {
 	dest := net.TCPDestination(net.ParseAddress(url.Hostname()), port)
 
 	s := &TCPNameServer{
-		destination: &dest,
-		ips:         make(map[string]*record),
+		destination: dest,
+		ips:         make(map[string]record),
 		pub:         pubsub.NewService(),
 		name:        prefix + "//" + dest.NetAddr(),
 	}
@@ -131,7 +131,7 @@ func (s *TCPNameServer) Cleanup() error {
 	}
 
 	if len(s.ips) == 0 {
-		s.ips = make(map[string]*record)
+		s.ips = make(map[string]record)
 	}
 
 	return nil
@@ -141,10 +141,7 @@ func (s *TCPNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
 	elapsed := time.Since(req.start)
 
 	s.Lock()
-	rec, found := s.ips[req.domain]
-	if !found {
-		rec = &record{}
-	}
+	rec := s.ips[req.domain]
 	updated := false
 
 	switch req.reqType {
@@ -278,30 +275,30 @@ func (s *TCPNameServer) findIPsForDomain(domain string, option dns_feature.IPOpt
 		return nil, errRecordNotFound
 	}
 
-	var err4 error
-	var err6 error
 	var ips []net.Address
-	var ip6 []net.Address
-
-	switch {
-	case option.IPv4Enable:
-		ips, err4 = record.A.getIPs()
-		fallthrough
-	case option.IPv6Enable:
-		ip6, err6 = record.AAAA.getIPs()
-		ips = append(ips, ip6...)
+	var lastErr error
+	if option.IPv4Enable {
+		a, err := record.A.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, a...)
 	}
 
-	if len(ips) > 0 {
-		return toNetIP(ips)
+	if option.IPv6Enable {
+		aaaa, err := record.AAAA.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, aaaa...)
 	}
 
-	if err4 != nil {
-		return nil, err4
+	if len(ips) > 0 {
+		return toNetIP(ips)
 	}
 
-	if err6 != nil {
-		return nil, err6
+	if lastErr != nil {
+		return nil, lastErr
 	}
 
 	return nil, dns_feature.ErrEmptyResponse

app/dns/nameserver_udp.go

@@ -29,9 +29,9 @@ import (
 type ClassicNameServer struct {
 	sync.RWMutex
 	name      string
-	address   *net.Destination
-	ips       map[string]*record
-	requests  map[uint16]*dnsRequest
+	address   net.Destination
+	ips       map[string]record
+	requests  map[uint16]dnsRequest
 	pub       *pubsub.Service
 	udpServer *udp.Dispatcher
 	cleanup   *task.Periodic
@@ -46,9 +46,9 @@ func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher
 	}
 
 	s := &ClassicNameServer{
-		address:  &address,
-		ips:      make(map[string]*record),
-		requests: make(map[uint16]*dnsRequest),
+		address:  address,
+		ips:      make(map[string]record),
+		requests: make(map[uint16]dnsRequest),
 		pub:      pubsub.NewService(),
 		name:     strings.ToUpper(address.String()),
 	}
@@ -85,7 +85,6 @@ func (s *ClassicNameServer) Cleanup() error {
 		}
 
 		if record.A == nil && record.AAAA == nil {
-			newError(s.name, " cleanup ", domain).AtDebug().WriteToLog()
 			delete(s.ips, domain)
 		} else {
 			s.ips[domain] = record
@@ -93,7 +92,7 @@ func (s *ClassicNameServer) Cleanup() error {
 	}
 
 	if len(s.ips) == 0 {
-		s.ips = make(map[string]*record)
+		s.ips = make(map[string]record)
 	}
 
 	for id, req := range s.requests {
@@ -103,7 +102,7 @@ func (s *ClassicNameServer) Cleanup() error {
 	}
 
 	if len(s.requests) == 0 {
-		s.requests = make(map[uint16]*dnsRequest)
+		s.requests = make(map[uint16]dnsRequest)
 	}
 
 	return nil
@@ -141,17 +140,15 @@ func (s *ClassicNameServer) HandleResponse(ctx context.Context, packet *udp_prot
 	elapsed := time.Since(req.start)
 	newError(s.name, " got answer: ", req.domain, " ", req.reqType, " -> ", ipRec.IP, " ", elapsed).AtInfo().WriteToLog()
 	if len(req.domain) > 0 && (rec.A != nil || rec.AAAA != nil) {
-		s.updateIP(req.domain, &rec)
+		s.updateIP(req.domain, rec)
 	}
 }
 
-func (s *ClassicNameServer) updateIP(domain string, newRec *record) {
+func (s *ClassicNameServer) updateIP(domain string, newRec record) {
 	s.Lock()
 
-	rec, found := s.ips[domain]
-	if !found {
-		rec = &record{}
-	}
+	newError(s.name, " updating IP records for domain:", domain).AtDebug().WriteToLog()
+	rec := s.ips[domain]
 
 	updated := false
 	if isNewer(rec.A, newRec.A) {
@@ -164,7 +161,6 @@ func (s *ClassicNameServer) updateIP(domain string, newRec *record) {
 	}
 
 	if updated {
-		newError(s.name, " updating IP records for domain:", domain).AtDebug().WriteToLog()
 		s.ips[domain] = rec
 	}
 	if newRec.A != nil {
@@ -187,7 +183,7 @@ func (s *ClassicNameServer) addPendingRequest(req *dnsRequest) {
 
 	id := req.msg.ID
 	req.expire = time.Now().Add(time.Second * 8)
-	s.requests[id] = req
+	s.requests[id] = *req
 }
 
 func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption) {
@@ -205,7 +201,7 @@ func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string, client
 		udpCtx = session.ContextWithContent(udpCtx, &session.Content{
 			Protocol: "dns",
 		})
-		s.udpServer.Dispatch(udpCtx, *s.address, b)
+		s.udpServer.Dispatch(udpCtx, s.address, b)
 	}
 }
 
@@ -218,30 +214,30 @@ func (s *ClassicNameServer) findIPsForDomain(domain string, option dns_feature.I
 		return nil, errRecordNotFound
 	}
 
-	var err4 error
-	var err6 error
 	var ips []net.Address
-	var ip6 []net.Address
-
-	switch {
-	case option.IPv4Enable:
-		ips, err4 = record.A.getIPs()
-		fallthrough
-	case option.IPv6Enable:
-		ip6, err6 = record.AAAA.getIPs()
-		ips = append(ips, ip6...)
+	var lastErr error
+	if option.IPv4Enable {
+		a, err := record.A.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, a...)
 	}
 
-	if len(ips) > 0 {
-		return toNetIP(ips)
+	if option.IPv6Enable {
+		aaaa, err := record.AAAA.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, aaaa...)
 	}
 
-	if err4 != nil {
-		return nil, err4
+	if len(ips) > 0 {
+		return toNetIP(ips)
 	}
 
-	if err6 != nil {
-		return nil, err6
+	if lastErr != nil {
+		return nil, lastErr
 	}
 
 	return nil, dns_feature.ErrEmptyResponse