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DNS: Fix some bugs; Refactors; Optimizations (#4659)
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patterniha
GitHub
parent
1c4e246788
commit
aa4134f4a6
22 changed files with 658 additions and 978 deletions
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@ -2,6 +2,7 @@ package dns
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import (
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"context"
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go_errors "errors"
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"strings"
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"sync"
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"sync/atomic"
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@ -13,7 +14,6 @@ import (
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"github.com/xtls/xray-core/common/net"
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"github.com/xtls/xray-core/common/protocol/dns"
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udp_proto "github.com/xtls/xray-core/common/protocol/udp"
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"github.com/xtls/xray-core/common/signal/pubsub"
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"github.com/xtls/xray-core/common/task"
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dns_feature "github.com/xtls/xray-core/features/dns"
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"github.com/xtls/xray-core/features/routing"
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@ -24,15 +24,13 @@ import (
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// ClassicNameServer implemented traditional UDP DNS.
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type ClassicNameServer struct {
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sync.RWMutex
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name string
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address *net.Destination
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ips map[string]*record
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requests map[uint16]*udpDnsRequest
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pub *pubsub.Service
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udpServer *udp.Dispatcher
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cleanup *task.Periodic
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reqID uint32
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queryStrategy QueryStrategy
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cacheController *CacheController
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address *net.Destination
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requests map[uint16]*udpDnsRequest
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udpServer *udp.Dispatcher
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requestsCleanup *task.Periodic
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reqID uint32
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clientIP net.IP
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}
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type udpDnsRequest struct {
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@ -41,23 +39,21 @@ type udpDnsRequest struct {
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}
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// NewClassicNameServer creates udp server object for remote resolving.
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func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher, queryStrategy QueryStrategy) *ClassicNameServer {
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func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher, disableCache bool, clientIP net.IP) *ClassicNameServer {
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// default to 53 if unspecific
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if address.Port == 0 {
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address.Port = net.Port(53)
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}
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s := &ClassicNameServer{
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address: &address,
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ips: make(map[string]*record),
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requests: make(map[uint16]*udpDnsRequest),
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pub: pubsub.NewService(),
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name: strings.ToUpper(address.String()),
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queryStrategy: queryStrategy,
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cacheController: NewCacheController(strings.ToUpper(address.String()), disableCache),
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address: &address,
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requests: make(map[uint16]*udpDnsRequest),
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clientIP: clientIP,
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}
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s.cleanup = &task.Periodic{
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s.requestsCleanup = &task.Periodic{
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Interval: time.Minute,
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Execute: s.Cleanup,
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Execute: s.RequestsCleanup,
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}
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s.udpServer = udp.NewDispatcher(dispatcher, s.HandleResponse)
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errors.LogInfo(context.Background(), "DNS: created UDP client initialized for ", address.NetAddr())
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@ -66,37 +62,17 @@ func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher
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// Name implements Server.
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func (s *ClassicNameServer) Name() string {
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return s.name
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return s.cacheController.name
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}
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// Cleanup clears expired items from cache
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func (s *ClassicNameServer) Cleanup() error {
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// RequestsCleanup clears expired items from cache
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func (s *ClassicNameServer) RequestsCleanup() error {
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now := time.Now()
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s.Lock()
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defer s.Unlock()
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if len(s.ips) == 0 && len(s.requests) == 0 {
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return errors.New(s.name, " nothing to do. stopping...")
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}
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for domain, record := range s.ips {
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if record.A != nil && record.A.Expire.Before(now) {
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record.A = nil
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}
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if record.AAAA != nil && record.AAAA.Expire.Before(now) {
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record.AAAA = nil
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}
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if record.A == nil && record.AAAA == nil {
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errors.LogDebug(context.Background(), s.name, " cleanup ", domain)
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delete(s.ips, domain)
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} else {
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s.ips[domain] = record
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}
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}
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if len(s.ips) == 0 {
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s.ips = make(map[string]*record)
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if len(s.requests) == 0 {
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return errors.New(s.Name(), " nothing to do. stopping...")
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}
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for id, req := range s.requests {
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@ -116,7 +92,7 @@ func (s *ClassicNameServer) Cleanup() error {
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func (s *ClassicNameServer) HandleResponse(ctx context.Context, packet *udp_proto.Packet) {
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ipRec, err := parseResponse(packet.Payload.Bytes())
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if err != nil {
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errors.LogError(ctx, s.name, " fail to parse responded DNS udp")
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errors.LogError(ctx, s.Name(), " fail to parse responded DNS udp")
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return
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}
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@ -129,14 +105,14 @@ func (s *ClassicNameServer) HandleResponse(ctx context.Context, packet *udp_prot
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}
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s.Unlock()
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if !ok {
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errors.LogError(ctx, s.name, " cannot find the pending request")
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errors.LogError(ctx, s.Name(), " cannot find the pending request")
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return
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}
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// if truncated, retry with EDNS0 option(udp payload size: 1350)
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if ipRec.RawHeader.Truncated {
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// if already has EDNS0 option, no need to retry
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if ok && len(req.msg.Additionals) == 0 {
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if len(req.msg.Additionals) == 0 {
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// copy necessary meta data from original request
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// and add EDNS0 option
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opt := new(dnsmessage.Resource)
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@ -154,51 +130,7 @@ func (s *ClassicNameServer) HandleResponse(ctx context.Context, packet *udp_prot
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}
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}
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var rec record
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switch req.reqType {
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case dnsmessage.TypeA:
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rec.A = ipRec
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case dnsmessage.TypeAAAA:
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rec.AAAA = ipRec
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}
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elapsed := time.Since(req.start)
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errors.LogInfo(ctx, s.name, " got answer: ", req.domain, " ", req.reqType, " -> ", ipRec.IP, " ", elapsed)
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if len(req.domain) > 0 && (rec.A != nil || rec.AAAA != nil) {
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s.updateIP(req.domain, &rec)
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}
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}
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func (s *ClassicNameServer) updateIP(domain string, newRec *record) {
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s.Lock()
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rec, found := s.ips[domain]
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if !found {
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rec = &record{}
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}
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updated := false
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if isNewer(rec.A, newRec.A) {
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rec.A = newRec.A
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updated = true
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}
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if isNewer(rec.AAAA, newRec.AAAA) {
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rec.AAAA = newRec.AAAA
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updated = true
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}
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if updated {
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errors.LogDebug(context.Background(), s.name, " updating IP records for domain:", domain)
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s.ips[domain] = rec
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}
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if newRec.A != nil {
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s.pub.Publish(domain+"4", nil)
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}
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if newRec.AAAA != nil {
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s.pub.Publish(domain+"6", nil)
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}
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s.Unlock()
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common.Must(s.cleanup.Start())
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s.cacheController.updateIP(&req.dnsRequest, ipRec)
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}
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func (s *ClassicNameServer) newReqID() uint16 {
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@ -207,17 +139,17 @@ func (s *ClassicNameServer) newReqID() uint16 {
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func (s *ClassicNameServer) addPendingRequest(req *udpDnsRequest) {
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s.Lock()
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defer s.Unlock()
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id := req.msg.ID
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req.expire = time.Now().Add(time.Second * 8)
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s.requests[id] = req
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s.Unlock()
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common.Must(s.requestsCleanup.Start())
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}
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func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption) {
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errors.LogDebug(ctx, s.name, " querying DNS for: ", domain)
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func (s *ClassicNameServer) sendQuery(ctx context.Context, _ chan<- error, domain string, option dns_feature.IPOption) {
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errors.LogDebug(ctx, s.Name(), " querying DNS for: ", domain)
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reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(clientIP, 0))
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reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(s.clientIP, 0))
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for _, req := range reqs {
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udpReq := &udpDnsRequest{
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@ -230,105 +162,50 @@ func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string, client
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}
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}
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func (s *ClassicNameServer) findIPsForDomain(domain string, option dns_feature.IPOption) ([]net.IP, uint32, error) {
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s.RLock()
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record, found := s.ips[domain]
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s.RUnlock()
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if !found {
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return nil, 0, errRecordNotFound
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}
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var err4 error
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var err6 error
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var ips []net.Address
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var ip6 []net.Address
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var ttl uint32
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if option.IPv4Enable {
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ips, ttl, err4 = record.A.getIPs()
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}
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if option.IPv6Enable {
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ip6, ttl, err6 = record.AAAA.getIPs()
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ips = append(ips, ip6...)
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}
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if len(ips) > 0 {
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netips, err := toNetIP(ips)
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return netips, ttl, err
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}
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if err4 != nil {
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return nil, 0, err4
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}
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if err6 != nil {
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return nil, 0, err6
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}
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return nil, 0, dns_feature.ErrEmptyResponse
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}
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// QueryIP implements Server.
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func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption, disableCache bool) ([]net.IP, uint32, error) {
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func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, option dns_feature.IPOption) ([]net.IP, uint32, error) {
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fqdn := Fqdn(domain)
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option = ResolveIpOptionOverride(s.queryStrategy, option)
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if !option.IPv4Enable && !option.IPv6Enable {
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return nil, 0, dns_feature.ErrEmptyResponse
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}
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sub4, sub6 := s.cacheController.registerSubscribers(fqdn, option)
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defer closeSubscribers(sub4, sub6)
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if disableCache {
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errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.name)
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if s.cacheController.disableCache {
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errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.Name())
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} else {
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ips, ttl, err := s.findIPsForDomain(fqdn, option)
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if err == nil || err == dns_feature.ErrEmptyResponse || dns_feature.RCodeFromError(err) == 3 {
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errors.LogDebugInner(ctx, err, s.name, " cache HIT ", domain, " -> ", ips)
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log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
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ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
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if !go_errors.Is(err, errRecordNotFound) {
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errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
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log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
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return ips, ttl, err
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}
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}
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// ipv4 and ipv6 belong to different subscription groups
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var sub4, sub6 *pubsub.Subscriber
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if option.IPv4Enable {
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sub4 = s.pub.Subscribe(fqdn + "4")
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defer sub4.Close()
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}
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if option.IPv6Enable {
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sub6 = s.pub.Subscribe(fqdn + "6")
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defer sub6.Close()
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}
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done := make(chan interface{})
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go func() {
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if sub4 != nil {
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select {
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case <-sub4.Wait():
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case <-ctx.Done():
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}
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}
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if sub6 != nil {
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select {
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case <-sub6.Wait():
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case <-ctx.Done():
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}
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}
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close(done)
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}()
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s.sendQuery(ctx, fqdn, clientIP, option)
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noResponseErrCh := make(chan error, 2)
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s.sendQuery(ctx, noResponseErrCh, fqdn, option)
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start := time.Now()
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for {
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ips, ttl, err := s.findIPsForDomain(fqdn, option)
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if err != errRecordNotFound {
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log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
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return ips, ttl, err
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}
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if sub4 != nil {
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select {
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case <-ctx.Done():
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return nil, 0, ctx.Err()
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case <-done:
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case err := <-noResponseErrCh:
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return nil, 0, err
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case <-sub4.Wait():
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sub4.Close()
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}
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}
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if sub6 != nil {
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select {
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case <-ctx.Done():
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return nil, 0, ctx.Err()
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case err := <-noResponseErrCh:
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return nil, 0, err
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case <-sub6.Wait():
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sub6.Close()
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}
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}
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ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
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log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
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return ips, ttl, err
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}
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