Add fakeip support

transport/fakeip/server.go

@@ -0,0 +1,83 @@
+package fakeip
+
+import (
+	"context"
+	"net/netip"
+	"os"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-dns"
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/logger"
+	N "github.com/sagernet/sing/common/network"
+
+	mDNS "github.com/miekg/dns"
+)
+
+var _ dns.Transport = (*Server)(nil)
+
+func init() {
+	dns.RegisterTransport([]string{"fakeip"}, NewTransport)
+}
+
+type Server struct {
+	name   string
+	router adapter.Router
+	store  adapter.FakeIPStore
+	logger logger.ContextLogger
+}
+
+func NewTransport(name string, ctx context.Context, logger logger.ContextLogger, dialer N.Dialer, link string) (dns.Transport, error) {
+	router := adapter.RouterFromContext(ctx)
+	if router == nil {
+		return nil, E.New("missing router in context")
+	}
+	return &Server{
+		name:   name,
+		router: router,
+		logger: logger,
+	}, nil
+}
+
+func (s *Server) Name() string {
+	return s.name
+}
+
+func (s *Server) Start() error {
+	s.store = s.router.FakeIPStore()
+	if s.store == nil {
+		return E.New("fakeip not enabled")
+	}
+	return nil
+}
+
+func (s *Server) Close() error {
+	return nil
+}
+
+func (s *Server) Raw() bool {
+	return false
+}
+
+func (s *Server) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, error) {
+	return nil, os.ErrInvalid
+}
+
+func (s *Server) Lookup(ctx context.Context, domain string, strategy dns.DomainStrategy) ([]netip.Addr, error) {
+	var addresses []netip.Addr
+	if strategy != dns.DomainStrategyUseIPv6 {
+		inet4Address, err := s.store.Create(domain, dns.DomainStrategyUseIPv4)
+		if err != nil {
+			return nil, err
+		}
+		addresses = append(addresses, inet4Address)
+	}
+	if strategy != dns.DomainStrategyUseIPv4 {
+		inet6Address, err := s.store.Create(domain, dns.DomainStrategyUseIPv6)
+		if err != nil {
+			return nil, err
+		}
+		addresses = append(addresses, inet6Address)
+	}
+	return addresses, nil
+}