Add trojan connection fallback

common/geosite/writer.go

@@ -20,13 +20,11 @@ func Write(writer io.Writer, domains map[string][]Item) error {
 	for _, code := range keys {
 		index[code] = content.Len()
 		for _, domain := range domains[code] {
-			err := rw.WriteByte(content, domain.Type)
+			content.WriteByte(domain.Type)
+			err := rw.WriteVString(content, domain.Value)
 			if err != nil {
 				return err
 			}
-			if err = rw.WriteVString(content, domain.Value); err != nil {
-				return err
-			}
 		}
 	}
 

docs/changelog.md

@@ -1,3 +1,13 @@
+#### 2022/08/20
+
+* Attempt to unwrap ip-in-fqdn socksaddr
+* Fix read packages in android 12
+* Fix route on some android devices
+* Improve linux process searcher
+* Fix write socks5 username password auth request
+* Skip bind connection with private destination to interface
+* Add trojan connection fallback
+
 #### 2022/08/19
 
 * Add Hysteria [Inbound](/configuration/inbound/hysteria) and [Outbund](/configuration/outbound/hysteria)

docs/configuration/inbound/trojan.md

@@ -20,7 +20,11 @@
           "password": "8JCsPssfgS8tiRwiMlhARg=="
         }
       ],
-      "tls": {}
+      "tls": {},
+      "fallback": {
+        "server": "127.0.0.0.1",
+        "server_port": 8080
+      }
     }
   ]
 }
@@ -73,3 +77,11 @@ Trojan users.
 #### tls
 
 TLS configuration, see [TLS inbound structure](/configuration/shared/tls/#inbound-structure).
+
+#### fallback
+
+!!! error ""
+
+    There is no evidence that GFW detects and blocks Trojan servers based on HTTP responses, and opening the standard http/s port on the server is a much bigger signature.
+
+Fallback server configuration. Disabled if empty.

go.mod

@@ -17,7 +17,7 @@ require (
 	github.com/sagernet/certmagic v0.0.0-20220819042630-4a57f8b6853a
 	github.com/sagernet/netlink v0.0.0-20220820041223-3cd8365d17ac
 	github.com/sagernet/quic-go v0.0.0-20220818150011-de611ab3e2bb
-	github.com/sagernet/sing v0.0.0-20220820042914-5304a2876b82
+	github.com/sagernet/sing v0.0.0-20220820125206-f0c2e5a0dcc2
 	github.com/sagernet/sing-dns v0.0.0-20220819010310-839eab1578c9
 	github.com/sagernet/sing-shadowsocks v0.0.0-20220819002358-7461bb09a8f6
 	github.com/sagernet/sing-tun v0.0.0-20220820054007-ce3573838b1e

go.sum

@@ -96,8 +96,8 @@ github.com/sagernet/quic-go v0.0.0-20220818150011-de611ab3e2bb h1:wc0yQ+SBn4TaTY
 github.com/sagernet/quic-go v0.0.0-20220818150011-de611ab3e2bb/go.mod h1:MIccjRKnPTjWwAOpl+AUGWOkzyTd9tERytudxu+1ra4=
 github.com/sagernet/sing v0.0.0-20220812082120-05f9836bff8f/go.mod h1:QVsS5L/ZA2Q5UhQwLrn0Trw+msNd/NPGEhBKR/ioWiY=
 github.com/sagernet/sing v0.0.0-20220817130738-ce854cda8522/go.mod h1:QVsS5L/ZA2Q5UhQwLrn0Trw+msNd/NPGEhBKR/ioWiY=
-github.com/sagernet/sing v0.0.0-20220820042914-5304a2876b82 h1:sKYbF5EN2AZXH0owjr4vHjFh/lmN3xHLVO8dm9eSnXE=
-github.com/sagernet/sing v0.0.0-20220820042914-5304a2876b82/go.mod h1:QVsS5L/ZA2Q5UhQwLrn0Trw+msNd/NPGEhBKR/ioWiY=
+github.com/sagernet/sing v0.0.0-20220820125206-f0c2e5a0dcc2 h1:9wlER8wPHDjqzDGpqoBWcZ6/MBUL00my7D+hdCCaNiI=
+github.com/sagernet/sing v0.0.0-20220820125206-f0c2e5a0dcc2/go.mod h1:QVsS5L/ZA2Q5UhQwLrn0Trw+msNd/NPGEhBKR/ioWiY=
 github.com/sagernet/sing-dns v0.0.0-20220819010310-839eab1578c9 h1:XgXSOJv8e7+98SJvg1f0luuPR33r4yFcmzxb3R//BTI=
 github.com/sagernet/sing-dns v0.0.0-20220819010310-839eab1578c9/go.mod h1:MAHy2IKZAA101t3Gr2x0ldwn6XuAs2cjGzSzHy5RhWk=
 github.com/sagernet/sing-shadowsocks v0.0.0-20220819002358-7461bb09a8f6 h1:JJfDeYYhWunvtxsU/mOVNTmFQmnzGx9dY034qG6G3g4=

inbound/trojan.go

@@ -14,6 +14,7 @@ import (
 	"github.com/sagernet/sing/common/auth"
 	E "github.com/sagernet/sing/common/exceptions"
 	F "github.com/sagernet/sing/common/format"
+	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
 	"github.com/sagernet/sing/protocol/trojan"
 )
@@ -22,9 +23,10 @@ var _ adapter.Inbound = (*Trojan)(nil)
 
 type Trojan struct {
 	myInboundAdapter
-	service   *trojan.Service[int]
-	users     []option.TrojanUser
-	tlsConfig *TLSConfig
+	service      *trojan.Service[int]
+	users        []option.TrojanUser
+	tlsConfig    *TLSConfig
+	fallbackAddr M.Socksaddr
 }
 
 func NewTrojan(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.TrojanInboundOptions) (*Trojan, error) {
@@ -40,7 +42,12 @@ func NewTrojan(ctx context.Context, router adapter.Router, logger log.ContextLog
 		},
 		users: options.Users,
 	}
-	service := trojan.NewService[int](adapter.NewUpstreamContextHandler(inbound.newConnection, inbound.newPacketConnection, inbound))
+	var fallbackHandler N.TCPConnectionHandler
+	if options.Fallback != nil && options.Fallback.Server != "" {
+		inbound.fallbackAddr = options.Fallback.Build()
+		fallbackHandler = adapter.NewUpstreamContextHandler(inbound.fallbackConnection, nil, nil)
+	}
+	service := trojan.NewService[int](adapter.NewUpstreamContextHandler(inbound.newConnection, inbound.newPacketConnection, inbound), fallbackHandler)
 	err := service.UpdateUsers(common.MapIndexed(options.Users, func(index int, it option.TrojanUser) int {
 		return index
 	}), common.Map(options.Users, func(it option.TrojanUser) string {
@@ -104,6 +111,12 @@ func (h *Trojan) newConnection(ctx context.Context, conn net.Conn, metadata adap
 	return h.router.RouteConnection(ctx, conn, metadata)
 }
 
+func (h *Trojan) fallbackConnection(ctx context.Context, conn net.Conn, metadata adapter.InboundContext) error {
+	h.logger.InfoContext(ctx, "fallback connection to ", h.fallbackAddr)
+	metadata.Destination = h.fallbackAddr
+	return h.router.RouteConnection(ctx, conn, metadata)
+}
+
 func (h *Trojan) newPacketConnection(ctx context.Context, conn N.PacketConn, metadata adapter.InboundContext) error {
 	userIndex, loaded := auth.UserFromContext[int](ctx)
 	if !loaded {

option/trojan.go

@@ -2,8 +2,9 @@ package option
 
 type TrojanInboundOptions struct {
 	ListenOptions
-	Users []TrojanUser       `json:"users,omitempty"`
-	TLS   *InboundTLSOptions `json:"tls,omitempty"`
+	Users    []TrojanUser       `json:"users,omitempty"`
+	TLS      *InboundTLSOptions `json:"tls,omitempty"`
+	Fallback *ServerOptions     `json:"fallback,omitempty"`
 }
 
 type TrojanUser struct {