feat/fix: dns query subscriptions group by A and AAAA. fix problem th…

…at empty result would poll dns server in DoH mode

app/dns/dohdns.go

@@ -12,6 +12,7 @@ import (
  "sync"
  "sync/atomic"
  "time"
+ dns_feature "v2ray.com/core/features/dns"
 
  "golang.org/x/net/dns/dnsmessage"
  "v2ray.com/core/common"
@@ -213,9 +214,13 @@ func (s *DoHNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
 
  if updated {
  s.ips[req.domain] = rec
- s.pub.Publish(req.domain, nil)
  }
-
+ switch req.reqType {
+ case dnsmessage.TypeA:
+ s.pub.Publish(req.domain+"4", nil)
+ case dnsmessage.TypeAAAA:
+ s.pub.Publish(req.domain+"6", nil)
+ }
  s.Unlock()
  common.Must(s.cleanup.Start())
 }
@@ -336,12 +341,15 @@ func (s *DoHNameServer) findIPsForDomain(domain string, option IPOption) ([]net.
  return nil, lastErr
  }
 
+ if (option.IPv4Enable && record.A != nil) || (option.IPv6Enable && record.AAAA != nil) {
+ return nil, dns_feature.ErrEmptyResponse
+ }
+
  return nil, errRecordNotFound
 }
 
 // QueryIP is called from dns.Server->queryIPTimeout
 func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option IPOption) ([]net.IP, error) {
-
  fqdn := Fqdn(domain)
 
  ips, err := s.findIPsForDomain(fqdn, option)
@@ -350,9 +358,32 @@ func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option IPOpt
  return ips, err
  }
 
- sub := s.pub.Subscribe(fqdn)
- defer sub.Close()
-
+ // ipv4 and ipv6 belong to different subscription groups
+ var sub4, sub6 *pubsub.Subscriber
+ if option.IPv4Enable {
+ sub4 = s.pub.Subscribe(fqdn + "4")
+ defer sub4.Close()
+ }
+ if option.IPv6Enable {
+ sub6 = s.pub.Subscribe(fqdn + "6")
+ defer sub6.Close()
+ }
+ done := make(chan interface{})
+ go func() {
+ if sub4 != nil {
+ select {
+ case <-sub4.Wait():
+ case <-ctx.Done():
+ }
+ }
+ if sub6 != nil {
+ select {
+ case <-sub6.Wait():
+ case <-ctx.Done():
+ }
+ }
+ close(done)
+ }()
  s.sendQuery(ctx, fqdn, option)
 
  for {
@@ -364,7 +395,7 @@ func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option IPOpt
  select {
  case <-ctx.Done():
  return nil, ctx.Err()
- case <-sub.Wait():
+ case <-done:
  }
  }
 }

app/dns/udpns.go

@@ -158,9 +158,13 @@ func (s *ClassicNameServer) updateIP(domain string, newRec record) {
 
  if updated {
  s.ips[domain] = rec
- s.pub.Publish(domain, nil)
  }
-
+ if newRec.A != nil {
+ s.pub.Publish(domain+"4", nil)
+ }
+ if newRec.AAAA != nil {
+ s.pub.Publish(domain+"6", nil)
+ }
  s.Unlock()
  common.Must(s.cleanup.Start())
 }
@@ -245,9 +249,32 @@ func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, option I
  return ips, err
  }
 
- sub := s.pub.Subscribe(fqdn)
- defer sub.Close()
-
+ // ipv4 and ipv6 belong to different subscription groups
+ var sub4, sub6 *pubsub.Subscriber
+ if option.IPv4Enable {
+ sub4 = s.pub.Subscribe(fqdn + "4")
+ defer sub4.Close()
+ }
+ if option.IPv6Enable {
+ sub6 = s.pub.Subscribe(fqdn + "6")
+ defer sub6.Close()
+ }
+ done := make(chan interface{})
+ go func() {
+ if sub4 != nil {
+ select {
+ case <-sub4.Wait():
+ case <-ctx.Done():
+ }
+ }
+ if sub6 != nil {
+ select {
+ case <-sub6.Wait():
+ case <-ctx.Done():
+ }
+ }
+ close(done)
+ }()
  s.sendQuery(ctx, fqdn, option)
 
  for {
@@ -259,7 +286,7 @@ func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, option I
  select {
  case <-ctx.Done():
  return nil, ctx.Err()
- case <-sub.Wait():
+ case <-done:
  }
  }
 }