[hysteria2] Masquerade inbound option style refactor. Mainly for supporting rewriteHost

docs/configuration/inbound/hysteria2.md

@@ -21,7 +21,15 @@
   ],
   "ignore_client_bandwidth": false,
   "tls": {},
-  "masquerade": "",
+  "masquerade": {
+    "type": "proxy",
+    "proxy": {
+      "url": "",
+      "rewriteHost": true
+    },
+    "file": "/var/www",
+    "string": "Some-Stuffs"
+  },
   "brutal_debug": false
 }
 ```
@@ -81,10 +89,13 @@ TLS configuration, see [TLS](/configuration/shared/tls/#inbound).
 
 HTTP3 server behavior when authentication fails.
 
-| Scheme       | Example                 | Description        |
-|--------------|-------------------------|--------------------|
-| `file`       | `file:///var/www`       | As a file server   |
-| `http/https` | `http://127.0.0.1:8080` | As a reverse proxy |
+| Key          | Example                        | Description          |
+|--------------|--------------------------------|----------------------|
+| `type`       | `file \| proxy \| string`      | masquerade modes     |
+| `file`       | `/var/www`                     | As a file server     |
+| `proxy.url`         | `http://127.0.0.1:8080` | As a reverse proxy   |
+| `proxy.rewriteHost` | `true \| false`         | Rewrite the Host header to match the proxied website |
+| `string`            | `Some-Stuffs`           | as a constant string server |
 
 A 404 page will be returned if empty.
 

docs/configuration/inbound/hysteria2.zh.md

@@ -21,7 +21,15 @@
   ],
   "ignore_client_bandwidth": false,
   "tls": {},
-  "masquerade": "",
+  "masquerade": {
+    "type": "proxy",
+    "proxy": {
+      "url": "",
+      "rewriteHost": true
+    },
+    "file": "/var/www",
+    "string": "Some-Stuffs"
+  },
   "brutal_debug": false
 }
 ```
@@ -83,6 +91,14 @@ HTTP3 服务器认证失败时的行为。
 | `file`       | `file:///var/www`       | 作为文件服务器 |
 | `http/https` | `http://127.0.0.1:8080` | 作为反向代理  |
 
+| Key          | 示例                           | 描述                 |
+|--------------|--------------------------------|----------------------|
+| `type`       | `file \| proxy \| string`      | 模式     |
+| `file`       | `/var/www`                     | 作为文件服务器 |
+| `proxy.url`         | `http://127.0.0.1:8080` | 作为反向代理   |
+| `proxy.rewriteHost` | `true \| false`         | 重写 `Host` 头以匹配被代理的网站 |
+| `string`            | `Some-Stuffs`           | 作为常量字符服务器 |
+
 如果为空，则返回 404 页。
 
 #### brutal_debug

option/hysteria2.go

@@ -1,5 +1,11 @@
 package option
 
+import (
+	"net/url"
+
+	"github.com/sagernet/sing/common/json"
+)
+
 type Hysteria2InboundOptions struct {
 	ListenOptions
 	UpMbps                int             `json:"up_mbps,omitempty"`
@@ -8,7 +14,7 @@ type Hysteria2InboundOptions struct {
 	Users                 []Hysteria2User `json:"users,omitempty"`
 	IgnoreClientBandwidth bool            `json:"ignore_client_bandwidth,omitempty"`
 	InboundTLSOptionsContainer
-	Masquerade  string `json:"masquerade,omitempty"`
+	Masquerade  Hysteria2Masquerade `json:"masquerade,omitempty"`
 	BrutalDebug bool                `json:"brutal_debug,omitempty"`
 }
 
@@ -33,3 +39,49 @@ type Hysteria2OutboundOptions struct {
 	OutboundTLSOptionsContainer
 	BrutalDebug bool `json:"brutal_debug,omitempty"`
 }
+
+type Hysteria2Masquerade struct {
+	Type   string                   `json:"type,omitempty"`
+	File   string                   `json:"file,omitempty"`
+	Proxy  Hysteria2MasqueradeProxy `json:"proxy,omitempty"`
+	String string                   `json:"string,omitempty"`
+}
+
+type Hysteria2MasqueradeProxy struct {
+	URL         string `json:"url,omitempty"`
+	RewriteHost bool   `json:"rewriteHost,omitempty"`
+}
+
+func (m *Hysteria2Masquerade) UnmarshalJSON(data []byte) error {
+	// Attempt to unmarshal data as a string
+	var str string
+	if err := json.Unmarshal(data, &str); err == nil {
+		masqueradeURL, err := url.Parse(str)
+		if err != nil || masqueradeURL.Scheme == "" {
+			m.String = str
+			m.Type = "string"
+			return nil
+		}
+		switch masqueradeURL.Scheme {
+		case "file":
+			m.File = masqueradeURL.Path
+			m.Type = "file"
+		case "http", "https":
+			m.Proxy.URL = str
+			m.Type = "proxy"
+		default:
+		}
+		return nil
+	}
+	// If not a string, attempt to unmarshal into the struct
+	type Alias Hysteria2Masquerade
+	aux := &struct {
+		*Alias
+	}{
+		Alias: (*Alias)(m),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	return nil
+}

protocol/hysteria2/inbound.go

@@ -60,25 +60,37 @@ func NewInbound(ctx context.Context, router adapter.Router, logger log.ContextLo
 		}
 	}
 	var masqueradeHandler http.Handler
-	if options.Masquerade != "" {
-		masqueradeURL, err := url.Parse(options.Masquerade)
+	if options.Masquerade != (option.Hysteria2Masquerade{}) {
+		switch options.Masquerade.Type {
+		case "file":
+			masqueradeHandler = http.FileServer(http.Dir(options.Masquerade.File))
+		case "proxy":
+			masqueradeURL, err := url.Parse(options.Masquerade.Proxy.URL)
 			if err != nil {
 				return nil, E.Cause(err, "parse masquerade URL")
 			}
-		switch masqueradeURL.Scheme {
-		case "file":
-			masqueradeHandler = http.FileServer(http.Dir(masqueradeURL.Path))
-		case "http", "https":
 			masqueradeHandler = &httputil.ReverseProxy{
 				Rewrite: func(r *httputil.ProxyRequest) {
 					r.SetURL(masqueradeURL)
+					// SetURL rewrites the Host header,
+					// but we don't want that if rewriteHost is false
+					if !options.Masquerade.Proxy.RewriteHost {
+						r.Out.Host = r.In.Host
+					}
 				},
 				ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
 					w.WriteHeader(http.StatusBadGateway)
 				},
 			}
+		case "string":
+			if options.Masquerade.String != "" {
+				masqueradeHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+					w.WriteHeader(http.StatusOK) // Use 200 OK by default
+					_, _ = w.Write([]byte(options.Masquerade.String))
+				})
+			}
 		default:
-			return nil, E.New("unknown masquerade URL scheme: ", masqueradeURL.Scheme)
+			return nil, E.New("unknown masquerade type: ", options.Masquerade.Type)
 		}
 	}
 	inbound := &Inbound{

test/hysteria2_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"net/netip"
 	"testing"
 
@@ -11,6 +12,35 @@ import (
 	"github.com/sagernet/sing/common/json/badoption"
 )
 
+func TestHysteria2InboundOptionsMasqueradeUnmarshalJSON(t *testing.T) {
+	t.Run("schema-file", func(t *testing.T) {
+		m := testMasqueradeUnmarshalJSON(t, []byte(`"file:///var/www"`))
+		if m.Type != "file" || m.File != "/var/www" {
+			t.Errorf("Unexpected values: %+v", m)
+		}
+	})
+	t.Run("schema-https", func(t *testing.T) {
+		m := testMasqueradeUnmarshalJSON(t, []byte(`"https://example.org:443"`))
+		if m.Type != "proxy" || m.Proxy.URL != "https://example.org:443" || m.Proxy.RewriteHost != false {
+			t.Errorf("Unexpected values: %+v", m)
+		}
+	})
+	t.Run("schema-string", func(t *testing.T) {
+		m := testMasqueradeUnmarshalJSON(t, []byte(`"Some-Stuffs"`))
+		if m.Type != "string" || m.String != "Some-Stuffs" {
+			t.Errorf("Unexpected values: %+v", m)
+		}
+	})
+}
+
+func testMasqueradeUnmarshalJSON(t *testing.T, jsonData []byte) option.Hysteria2Masquerade {
+	var m option.Hysteria2Masquerade
+	if err := json.Unmarshal(jsonData, &m); err != nil {
+		t.Fatalf("Unmarshal failed: %v", err)
+	}
+	return m
+}
+
 func TestHysteria2Self(t *testing.T) {
 	t.Run("self", func(t *testing.T) {
 		testHysteria2Self(t, "")