Move predefined DNS server to rule action

common/dialer/resolve.go

@@ -44,6 +44,20 @@ type resolveDialer struct {
 }
 
 func NewResolveDialer(ctx context.Context, dialer N.Dialer, parallel bool, server string, queryOptions adapter.DNSQueryOptions, fallbackDelay time.Duration) ResolveDialer {
+	if parallelDialer, isParallel := dialer.(ParallelInterfaceDialer); isParallel {
+		return &resolveParallelNetworkDialer{
+			resolveDialer{
+				transport:     service.FromContext[adapter.DNSTransportManager](ctx),
+				router:        service.FromContext[adapter.DNSRouter](ctx),
+				dialer:        dialer,
+				parallel:      parallel,
+				server:        server,
+				queryOptions:  queryOptions,
+				fallbackDelay: fallbackDelay,
+			},
+			parallelDialer,
+		}
+	}
 	return &resolveDialer{
 		transport:     service.FromContext[adapter.DNSTransportManager](ctx),
 		router:        service.FromContext[adapter.DNSRouter](ctx),
@@ -60,21 +74,6 @@ type resolveParallelNetworkDialer struct {
 	dialer ParallelInterfaceDialer
 }
 
-func NewResolveParallelInterfaceDialer(ctx context.Context, dialer ParallelInterfaceDialer, parallel bool, server string, queryOptions adapter.DNSQueryOptions, fallbackDelay time.Duration) ParallelInterfaceResolveDialer {
-	return &resolveParallelNetworkDialer{
-		resolveDialer{
-			transport:     service.FromContext[adapter.DNSTransportManager](ctx),
-			router:        service.FromContext[adapter.DNSRouter](ctx),
-			dialer:        dialer,
-			parallel:      parallel,
-			server:        server,
-			queryOptions:  queryOptions,
-			fallbackDelay: fallbackDelay,
-		},
-		dialer,
-	}
-}
-
 func (d *resolveDialer) initialize() error {
 	d.initOnce.Do(d.initServer)
 	return d.initErr

constant/dns.go

@@ -15,19 +15,19 @@ const (
 )
 
 const (
-	DNSTypeLegacy     = "legacy"
-	DNSTypeUDP        = "udp"
-	DNSTypeTCP        = "tcp"
-	DNSTypeTLS        = "tls"
-	DNSTypeHTTPS      = "https"
-	DNSTypeQUIC       = "quic"
-	DNSTypeHTTP3      = "h3"
-	DNSTypeHosts      = "hosts"
-	DNSTypeLocal      = "local"
-	DNSTypePreDefined = "predefined"
-	DNSTypeFakeIP     = "fakeip"
-	DNSTypeDHCP       = "dhcp"
-	DNSTypeTailscale  = "tailscale"
+	DNSTypeLegacy      = "legacy"
+	DNSTypeLegacyRcode = "legacy_rcode"
+	DNSTypeUDP         = "udp"
+	DNSTypeTCP         = "tcp"
+	DNSTypeTLS         = "tls"
+	DNSTypeHTTPS       = "https"
+	DNSTypeQUIC        = "quic"
+	DNSTypeHTTP3       = "h3"
+	DNSTypeLocal       = "local"
+	DNSTypeHosts       = "hosts"
+	DNSTypeFakeIP      = "fakeip"
+	DNSTypeDHCP        = "dhcp"
+	DNSTypeTailscale   = "tailscale"
 )
 
 const (

constant/rule.go

@@ -33,6 +33,7 @@ const (
 	RuleActionTypeHijackDNS    = "hijack-dns"
 	RuleActionTypeSniff        = "sniff"
 	RuleActionTypeResolve      = "resolve"
+	RuleActionTypePredefined   = "predefined"
 )
 
 const (

dns/router.go

@@ -190,6 +190,8 @@ func (r *Router) matchDNS(ctx context.Context, allowFakeIP bool, ruleIndex int,
 				}
 			case *R.RuleActionReject:
 				return nil, currentRule, currentRuleIndex
+			case *R.RuleActionPredefined:
+				return nil, currentRule, currentRuleIndex
 			}
 		}
 	}
@@ -260,6 +262,21 @@ func (r *Router) Exchange(ctx context.Context, message *mDNS.Msg, options adapte
 						case C.RuleActionRejectMethodDrop:
 							return nil, tun.ErrDrop
 						}
+					case *R.RuleActionPredefined:
+						return &mDNS.Msg{
+							MsgHdr: mDNS.MsgHdr{
+								Id:                 message.Id,
+								Response:           true,
+								Authoritative:      true,
+								RecursionDesired:   true,
+								RecursionAvailable: true,
+								Rcode:              action.Rcode,
+							},
+							Question: message.Question,
+							Answer:   action.Answer,
+							Ns:       action.Ns,
+							Extra:    action.Extra,
+						}, nil
 					}
 				}
 				var responseCheck func(responseAddrs []netip.Addr) bool
@@ -376,6 +393,20 @@ func (r *Router) Lookup(ctx context.Context, domain string, options adapter.DNSQ
 					case C.RuleActionRejectMethodDrop:
 						return nil, tun.ErrDrop
 					}
+				case *R.RuleActionPredefined:
+					if action.Rcode != mDNS.RcodeSuccess {
+						err = RcodeError(action.Rcode)
+					} else {
+						for _, answer := range action.Answer {
+							switch record := answer.(type) {
+							case *mDNS.A:
+								responseAddrs = append(responseAddrs, M.AddrFromIP(record.A))
+							case *mDNS.AAAA:
+								responseAddrs = append(responseAddrs, M.AddrFromIP(record.AAAA))
+							}
+						}
+					}
+					goto response
 				}
 			}
 			var responseCheck func(responseAddrs []netip.Addr) bool
@@ -395,6 +426,7 @@ func (r *Router) Lookup(ctx context.Context, domain string, options adapter.DNSQ
 			printResult()
 		}
 	}
+response:
 	printResult()
 	if len(responseAddrs) > 0 {
 		r.logger.InfoContext(ctx, "lookup succeed for ", domain, ": ", strings.Join(F.MapToString(responseAddrs), " "))

include/registry.go

@@ -107,7 +107,6 @@ func DNSTransportRegistry() *dns.TransportRegistry {
 	transport.RegisterUDP(registry)
 	transport.RegisterTLS(registry)
 	transport.RegisterHTTPS(registry)
-	transport.RegisterPredefined(registry)
 	hosts.RegisterTransport(registry)
 	local.RegisterTransport(registry)
 	fakeip.RegisterTransport(registry)

option/dns.go

@@ -46,7 +46,46 @@ func (o *DNSOptions) UnmarshalJSONContext(ctx context.Context, content []byte) e
 	}
 	legacyOptions := o.LegacyDNSOptions
 	o.LegacyDNSOptions = LegacyDNSOptions{}
-	return badjson.UnmarshallExcludedContext(ctx, content, legacyOptions, &o.RawDNSOptions)
+	err = badjson.UnmarshallExcludedContext(ctx, content, legacyOptions, &o.RawDNSOptions)
+	if err != nil {
+		return err
+	}
+	rcodeMap := make(map[string]int)
+	o.Servers = common.Filter(o.Servers, func(it NewDNSServerOptions) bool {
+		if it.Type == C.DNSTypeLegacyRcode {
+			rcodeMap[it.Tag] = it.Options.(int)
+			return false
+		}
+		return true
+	})
+	if len(rcodeMap) > 0 {
+		for i := 0; i < len(o.Rules); i++ {
+			rewriteRcode(rcodeMap, &o.Rules[i])
+		}
+	}
+	return nil
+}
+
+func rewriteRcode(rcodeMap map[string]int, rule *DNSRule) {
+	switch rule.Type {
+	case C.RuleTypeDefault:
+		rewriteRcodeAction(rcodeMap, &rule.DefaultOptions.DNSRuleAction)
+	case C.RuleTypeLogical:
+		rewriteRcodeAction(rcodeMap, &rule.LogicalOptions.DNSRuleAction)
+	}
+}
+
+func rewriteRcodeAction(rcodeMap map[string]int, ruleAction *DNSRuleAction) {
+	if ruleAction.Action != C.RuleActionTypeRoute {
+		return
+	}
+	rcode, loaded := rcodeMap[ruleAction.RouteOptions.Server]
+	if !loaded {
+		return
+	}
+	ruleAction.Action = C.RuleActionTypePredefined
+	ruleAction.PredefinedOptions.Rcode = common.Ptr(DNSRCode(rcode))
+	return
 }
 
 type DNSClientOptions struct {
@@ -243,14 +282,8 @@ func (o *NewDNSServerOptions) Upgrade(ctx context.Context) error {
 		default:
 			return E.New("unknown rcode: ", serverURL.Host)
 		}
-		o.Type = C.DNSTypePreDefined
-		o.Options = &PredefinedDNSServerOptions{
-			Responses: []DNSResponseOptions{
-				{
-					RCode: common.Ptr(DNSRCode(rcode)),
-				},
-			},
-		}
+		o.Type = C.DNSTypeLegacyRcode
+		o.Options = rcode
 	case C.DNSTypeDHCP:
 		o.Type = C.DNSTypeDHCP
 		dhcpOptions := DHCPDNSServerOptions{}

option/dns_record.go

@@ -3,30 +3,14 @@ package option
 import (
 	"encoding/base64"
 
-	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
 	E "github.com/sagernet/sing/common/exceptions"
 	"github.com/sagernet/sing/common/json"
-	"github.com/sagernet/sing/common/json/badoption"
 	M "github.com/sagernet/sing/common/metadata"
 
 	"github.com/miekg/dns"
 )
 
-type PredefinedDNSServerOptions struct {
-	Responses []DNSResponseOptions `json:"responses,omitempty"`
-}
-
-type DNSResponseOptions struct {
-	Query     badoption.Listable[string]       `json:"query,omitempty"`
-	QueryType badoption.Listable[DNSQueryType] `json:"query_type,omitempty"`
-
-	RCode  *DNSRCode                            `json:"rcode,omitempty"`
-	Answer badoption.Listable[DNSRecordOptions] `json:"answer,omitempty"`
-	Ns     badoption.Listable[DNSRecordOptions] `json:"ns,omitempty"`
-	Extra  badoption.Listable[DNSRecordOptions] `json:"extra,omitempty"`
-}
-
 type DNSRCode int
 
 func (r DNSRCode) MarshalJSON() ([]byte, error) {
@@ -64,49 +48,6 @@ func (r *DNSRCode) Build() int {
 	return int(*r)
 }
 
-func (o DNSResponseOptions) Build() ([]dns.Question, *dns.Msg, error) {
-	var questions []dns.Question
-	if len(o.Query) == 0 && len(o.QueryType) == 0 {
-		questions = []dns.Question{{Qclass: dns.ClassINET}}
-	} else if len(o.Query) == 0 {
-		for _, queryType := range o.QueryType {
-			questions = append(questions, dns.Question{
-				Qtype:  uint16(queryType),
-				Qclass: dns.ClassINET,
-			})
-		}
-	} else if len(o.QueryType) == 0 {
-		for _, domain := range o.Query {
-			questions = append(questions, dns.Question{
-				Name:   dns.Fqdn(domain),
-				Qclass: dns.ClassINET,
-			})
-		}
-	} else {
-		for _, queryType := range o.QueryType {
-			for _, domain := range o.Query {
-				questions = append(questions, dns.Question{
-					Name:   dns.Fqdn(domain),
-					Qtype:  uint16(queryType),
-					Qclass: dns.ClassINET,
-				})
-			}
-		}
-	}
-	return questions, &dns.Msg{
-		MsgHdr: dns.MsgHdr{
-			Response:           true,
-			Rcode:              o.RCode.Build(),
-			Authoritative:      true,
-			RecursionDesired:   true,
-			RecursionAvailable: true,
-		},
-		Answer: common.Map(o.Answer, DNSRecordOptions.build),
-		Ns:     common.Map(o.Ns, DNSRecordOptions.build),
-		Extra:  common.Map(o.Extra, DNSRecordOptions.build),
-	}, nil
-}
-
 type DNSRecordOptions struct {
 	dns.RR
 	fromBase64 bool
@@ -156,6 +97,6 @@ func (o *DNSRecordOptions) unmarshalBase64(binary []byte) error {
 	return nil
 }
 
-func (o DNSRecordOptions) build() dns.RR {
+func (o DNSRecordOptions) Build() dns.RR {
 	return o.RR
 }