chore: adjust the internal code structure of the dns module

component/resolver/service.go

@@ -6,15 +6,15 @@ import (
 	D "github.com/miekg/dns"
 )
 
-var DefaultLocalServer LocalServer
+var DefaultService Service
 
-type LocalServer interface {
+type Service interface {
 	ServeMsg(ctx context.Context, msg *D.Msg) (*D.Msg, error)
 }
 
 // ServeMsg with a dns.Msg, return resolve dns.Msg
 func ServeMsg(ctx context.Context, msg *D.Msg) (*D.Msg, error) {
-	if server := DefaultLocalServer; server != nil {
+	if server := DefaultService; server != nil {
 		return server.ServeMsg(ctx, msg)
 	}
 

context/dns.go

@@ -2,10 +2,10 @@ package context
 
 import (
 	"context"
+
 	"github.com/metacubex/mihomo/common/utils"
 
 	"github.com/gofrs/uuid/v5"
-	"github.com/miekg/dns"
 )
 
 const (
@@ -17,17 +17,15 @@ const (
 type DNSContext struct {
 	context.Context
 
-	id  uuid.UUID
-	msg *dns.Msg
-	tp  string
+	id uuid.UUID
+	tp string
 }
 
-func NewDNSContext(ctx context.Context, msg *dns.Msg) *DNSContext {
+func NewDNSContext(ctx context.Context) *DNSContext {
 	return &DNSContext{
 		Context: ctx,
 
-		id:  utils.NewUUIDV4(),
-		msg: msg,
+		id: utils.NewUUIDV4(),
 	}
 }
 

dns/local.go

@@ -1,20 +0,0 @@
-package dns
-
-import (
-	"context"
-
-	D "github.com/miekg/dns"
-)
-
-type LocalServer struct {
-	handler handler
-}
-
-// ServeMsg implement resolver.LocalServer ResolveMsg
-func (s *LocalServer) ServeMsg(ctx context.Context, msg *D.Msg) (*D.Msg, error) {
-	return handlerWithContext(ctx, s.handler, msg)
-}
-
-func NewLocalServer(resolver *Resolver, mapper *ResolverEnhancer) *LocalServer {
-	return &LocalServer{handler: NewHandler(resolver, mapper)}
-}

dns/middleware.go

@@ -7,22 +7,22 @@ import (
 
 	"github.com/metacubex/mihomo/common/lru"
 	"github.com/metacubex/mihomo/component/fakeip"
-	R "github.com/metacubex/mihomo/component/resolver"
+	"github.com/metacubex/mihomo/component/resolver"
 	C "github.com/metacubex/mihomo/constant"
-	"github.com/metacubex/mihomo/context"
+	icontext "github.com/metacubex/mihomo/context"
 	"github.com/metacubex/mihomo/log"
 
 	D "github.com/miekg/dns"
 )
 
 type (
-	handler    func(ctx *context.DNSContext, r *D.Msg) (*D.Msg, error)
+	handler    func(ctx *icontext.DNSContext, r *D.Msg) (*D.Msg, error)
 	middleware func(next handler) handler
 )
 
 func withHosts(mapping *lru.LruCache[netip.Addr, string]) middleware {
 	return func(next handler) handler {
-		return func(ctx *context.DNSContext, r *D.Msg) (*D.Msg, error) {
+		return func(ctx *icontext.DNSContext, r *D.Msg) (*D.Msg, error) {
 			q := r.Question[0]
 
 			if !isIPRequest(q) {
@@ -36,7 +36,7 @@ func withHosts(mapping *lru.LruCache[netip.Addr, string]) middleware {
 				rr.Target = domain + "."
 				resp.Answer = append([]D.RR{rr}, resp.Answer...)
 			}
-			record, ok := R.DefaultHosts.Search(host, q.Qtype != D.TypeA && q.Qtype != D.TypeAAAA)
+			record, ok := resolver.DefaultHosts.Search(host, q.Qtype != D.TypeA && q.Qtype != D.TypeAAAA)
 			if !ok {
 				if record != nil && record.IsDomain {
 					// replace request domain
@@ -88,7 +88,7 @@ func withHosts(mapping *lru.LruCache[netip.Addr, string]) middleware {
 				return next(ctx, r)
 			}
 
-			ctx.SetType(context.DNSTypeHost)
+			ctx.SetType(icontext.DNSTypeHost)
 			msg.SetRcode(r, D.RcodeSuccess)
 			msg.Authoritative = true
 			msg.RecursionAvailable = true
@@ -99,7 +99,7 @@ func withHosts(mapping *lru.LruCache[netip.Addr, string]) middleware {
 
 func withMapping(mapping *lru.LruCache[netip.Addr, string]) middleware {
 	return func(next handler) handler {
-		return func(ctx *context.DNSContext, r *D.Msg) (*D.Msg, error) {
+		return func(ctx *icontext.DNSContext, r *D.Msg) (*D.Msg, error) {
 			q := r.Question[0]
 
 			if !isIPRequest(q) {
@@ -149,7 +149,7 @@ func withMapping(mapping *lru.LruCache[netip.Addr, string]) middleware {
 
 func withFakeIP(fakePool *fakeip.Pool) middleware {
 	return func(next handler) handler {
-		return func(ctx *context.DNSContext, r *D.Msg) (*D.Msg, error) {
+		return func(ctx *icontext.DNSContext, r *D.Msg) (*D.Msg, error) {
 			q := r.Question[0]
 
 			host := strings.TrimRight(q.Name, ".")
@@ -173,7 +173,7 @@ func withFakeIP(fakePool *fakeip.Pool) middleware {
 			msg := r.Copy()
 			msg.Answer = []D.RR{rr}
 
-			ctx.SetType(context.DNSTypeFakeIP)
+			ctx.SetType(icontext.DNSTypeFakeIP)
 			setMsgTTL(msg, 1)
 			msg.SetRcode(r, D.RcodeSuccess)
 			msg.Authoritative = true
@@ -185,8 +185,8 @@ func withFakeIP(fakePool *fakeip.Pool) middleware {
 }
 
 func withResolver(resolver *Resolver) handler {
-	return func(ctx *context.DNSContext, r *D.Msg) (*D.Msg, error) {
-		ctx.SetType(context.DNSTypeRaw)
+	return func(ctx *icontext.DNSContext, r *D.Msg) (*D.Msg, error) {
+		ctx.SetType(icontext.DNSTypeRaw)
 
 		q := r.Question[0]
 
@@ -218,8 +218,8 @@ func compose(middlewares []middleware, endpoint handler) handler {
 	return h
 }
 
-func NewHandler(resolver *Resolver, mapper *ResolverEnhancer) handler {
-	middlewares := []middleware{}
+func newHandler(resolver *Resolver, mapper *ResolverEnhancer) handler {
+	var middlewares []middleware
 
 	if mapper.useHosts {
 		middlewares = append(middlewares, withHosts(mapper.mapping))

dns/server.go

@@ -1,13 +1,12 @@
 package dns
 
 import (
-	stdContext "context"
-	"errors"
+	"context"
 	"net"
 
 	"github.com/metacubex/mihomo/adapter/inbound"
 	"github.com/metacubex/mihomo/common/sockopt"
-	"github.com/metacubex/mihomo/context"
+	"github.com/metacubex/mihomo/component/resolver"
 	"github.com/metacubex/mihomo/log"
 
 	D "github.com/miekg/dns"
@@ -21,39 +20,32 @@ var (
 )
 
 type Server struct {
-	handler   handler
+	service   resolver.Service
 	tcpServer *D.Server
 	udpServer *D.Server
 }
 
 // ServeDNS implement D.Handler ServeDNS
 func (s *Server) ServeDNS(w D.ResponseWriter, r *D.Msg) {
-	msg, err := handlerWithContext(stdContext.Background(), s.handler, r)
+	msg, err := s.service.ServeMsg(context.Background(), r)
 	if err != nil {
-		D.HandleFailed(w, r)
+		m := new(D.Msg)
+		m.SetRcode(r, D.RcodeServerFailure)
+		// does not matter if this write fails
+		w.WriteMsg(m)
 		return
 	}
 	msg.Compress = true
 	w.WriteMsg(msg)
 }
 
-func handlerWithContext(stdCtx stdContext.Context, handler handler, msg *D.Msg) (*D.Msg, error) {
-	if len(msg.Question) == 0 {
-		return nil, errors.New("at least one question is required")
-	}
-
-	ctx := context.NewDNSContext(stdCtx, msg)
-	return handler(ctx, msg)
+func (s *Server) SetService(service resolver.Service) {
+	s.service = service
 }
 
-func (s *Server) SetHandler(handler handler) {
-	s.handler = handler
-}
-
-func ReCreateServer(addr string, resolver *Resolver, mapper *ResolverEnhancer) {
-	if addr == address && resolver != nil && mapper != nil {
-		handler := NewHandler(resolver, mapper)
-		server.SetHandler(handler)
+func ReCreateServer(addr string, service resolver.Service) {
+	if addr == address && service != nil {
+		server.SetService(service)
 		return
 	}
 
@@ -67,10 +59,10 @@ func ReCreateServer(addr string, resolver *Resolver, mapper *ResolverEnhancer) {
 		server.udpServer = nil
 	}
 
-	server.handler = nil
+	server.service = nil
 	address = ""
 
-	if addr == "" || resolver == nil || mapper == nil {
+	if addr == "" || service == nil {
 		return
 	}
 
@@ -87,8 +79,7 @@ func ReCreateServer(addr string, resolver *Resolver, mapper *ResolverEnhancer) {
 	}
 
 	address = addr
-	handler := NewHandler(resolver, mapper)
-	server = &Server{handler: handler}
+	server = &Server{service: service}
 
 	go func() {
 		p, err := inbound.ListenPacket("udp", addr)

dns/service.go

@@ -0,0 +1,29 @@
+package dns
+
+import (
+	"context"
+	"errors"
+
+	"github.com/metacubex/mihomo/component/resolver"
+	icontext "github.com/metacubex/mihomo/context"
+	D "github.com/miekg/dns"
+)
+
+type Service struct {
+	handler handler
+}
+
+// ServeMsg implement [resolver.Service] ResolveMsg
+func (s *Service) ServeMsg(ctx context.Context, msg *D.Msg) (*D.Msg, error) {
+	if len(msg.Question) == 0 {
+		return nil, errors.New("at least one question is required")
+	}
+
+	return s.handler(icontext.NewDNSContext(ctx), msg)
+}
+
+var _ resolver.Service = (*Service)(nil)
+
+func NewService(resolver *Resolver, mapper *ResolverEnhancer) *Service {
+	return &Service{handler: newHandler(resolver, mapper)}
+}

hub/executor/executor.go

@@ -240,10 +240,10 @@ func updateDNS(c *config.DNS, generalIPv6 bool) {
 	if !c.Enable {
 		resolver.DefaultResolver = nil
 		resolver.DefaultHostMapper = nil
-		resolver.DefaultLocalServer = nil
+		resolver.DefaultService = nil
 		resolver.ProxyServerHostResolver = nil
 		resolver.DirectHostResolver = nil
-		dns.ReCreateServer("", nil, nil)
+		dns.ReCreateServer("", nil)
 		return
 	}
 
@@ -273,9 +273,11 @@ func updateDNS(c *config.DNS, generalIPv6 bool) {
 		m.PatchFrom(old.(*dns.ResolverEnhancer))
 	}
 
+	s := dns.NewService(r.Resolver, m)
+
 	resolver.DefaultResolver = r
 	resolver.DefaultHostMapper = m
-	resolver.DefaultLocalServer = dns.NewLocalServer(r.Resolver, m)
+	resolver.DefaultService = s
 	resolver.UseSystemHosts = c.UseSystemHosts
 
 	if r.ProxyResolver.Invalid() {
@@ -290,7 +292,7 @@ func updateDNS(c *config.DNS, generalIPv6 bool) {
 		resolver.DirectHostResolver = r.Resolver
 	}
 
-	dns.ReCreateServer(c.Listen, r.Resolver, m)
+	dns.ReCreateServer(c.Listen, s)
 }
 
 func updateHosts(tree *trie.DomainTrie[resolver.HostValue]) {