Pin native Xray transport params to xray-core defaults; keep only safe knobs

Remove the transport-shaping tuning footguns that could break data flow if
misconfigured, and hardcode them to xray-core / Go net/http2 defaults instead:

- HTTP/2: stop overriding MaxConcurrentStreams and the per-conn/per-stream upload
  buffers; use Go's defaults exactly like xray-core's splithttp hub does.
- XHTTP reorder buffer default is now 30 (xray-core scMaxBufferedPosts), still
  overridable per-inbound from the generated config.
- Mux per-connection session cap, mux UDP idle/read/write buffers, and the XHTTP
  session cap are now fixed constants rather than admin knobs.

The XrayNativeTuning struct and admin UI keep only the operator-safe controls:
Go GOMAXPROCS, the global mux-session DoS cap, and the packet-trace debug toggle.
Old config.json files with the removed keys still load (unknown fields ignored).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

admin/assets/js/08-server-config.js

@@ -29,49 +29,25 @@ function toggleUdpgwFields(on) {
 }
 
 
+// Only operator-safe knobs remain. Transport buffers (HTTP/2 flow control, XHTTP
+// reorder buffer, mux/UDP buffers) are fixed to xray-core defaults in the backend
+// and are no longer exposed here, so they cannot be misconfigured.
 const XRAY_NATIVE_TUNING_DEFAULTS = {
   safe: {
     runtime_gomaxprocs: 0,
-    mux_max_sessions: 64,
     mux_global_sessions: 8192,
-    mux_udp_idle_ms: 120000,
-    mux_udp_read_buffer: 131072,
-    mux_udp_write_buffer: 131072,
-    xhttp_max_sessions: 4096,
-    xhttp_buffered_posts: 128,
-    h2_max_concurrent_streams: 256,
-    h2_upload_buffer_conn: 1048576,
-    h2_upload_buffer_stream: 262144,
     trace_packets: false,
   },
   "2k": {
     runtime_gomaxprocs: 0,
-    mux_max_sessions: 128,
     mux_global_sessions: 32768,
-    mux_udp_idle_ms: 120000,
-    mux_udp_read_buffer: 262144,
-    mux_udp_write_buffer: 262144,
-    xhttp_max_sessions: 16384,
-    xhttp_buffered_posts: 256,
-    h2_max_concurrent_streams: 1024,
-    h2_upload_buffer_conn: 1048576,
-    h2_upload_buffer_stream: 262144,
     trace_packets: false,
   },
 };
 
 const XRAY_NATIVE_TUNING_FIELDS = {
   runtime_gomaxprocs: "cfgXrayRuntimeGomaxprocs",
-  mux_max_sessions: "cfgXrayMuxMaxSessions",
   mux_global_sessions: "cfgXrayMuxGlobalSessions",
-  mux_udp_idle_ms: "cfgXrayMuxUdpIdleMs",
-  mux_udp_read_buffer: "cfgXrayMuxUdpRbuf",
-  mux_udp_write_buffer: "cfgXrayMuxUdpWbuf",
-  xhttp_max_sessions: "cfgXrayXhttpMaxSessions",
-  xhttp_buffered_posts: "cfgXrayXhttpBufferedPosts",
-  h2_max_concurrent_streams: "cfgXrayH2MaxStreams",
-  h2_upload_buffer_conn: "cfgXrayH2UploadConn",
-  h2_upload_buffer_stream: "cfgXrayH2UploadStream",
 };
 
 function setXrayNativeTuningDefaults(profile = "2k") {

admin/index.html

@@ -1192,22 +1192,13 @@
             <summary style="cursor:pointer;font-size:.76rem;font-weight:700;color:var(--text);">Native Xray scale tuning</summary>
             <div class="grid2" style="margin-top:10px;gap:8px;">
               <div class="field"><label>Go CPU threads (GOMAXPROCS)</label><input type="number" min="0" id="cfgXrayRuntimeGomaxprocs" placeholder="0 = all CPU cores"/></div>
-              <div class="field"><label>Mux sessions per connection</label><input type="number" min="1" id="cfgXrayMuxMaxSessions" placeholder="128"/></div>
               <div class="field"><label>Global mux backend sessions</label><input type="number" min="1" id="cfgXrayMuxGlobalSessions" placeholder="32768"/></div>
-              <div class="field"><label>Mux UDP idle ms</label><input type="number" min="1000" id="cfgXrayMuxUdpIdleMs" placeholder="15000"/></div>
-              <div class="field"><label>Mux UDP read buffer bytes</label><input type="number" min="4096" id="cfgXrayMuxUdpRbuf" placeholder="262144"/></div>
-              <div class="field"><label>Mux UDP write buffer bytes</label><input type="number" min="4096" id="cfgXrayMuxUdpWbuf" placeholder="262144"/></div>
-              <div class="field"><label>XHTTP max active sessions</label><input type="number" min="1" id="cfgXrayXhttpMaxSessions" placeholder="16384"/></div>
-              <div class="field"><label>XHTTP buffered posts</label><input type="number" min="1" id="cfgXrayXhttpBufferedPosts" placeholder="64"/></div>
-              <div class="field"><label>HTTP/2 max streams</label><input type="number" min="1" id="cfgXrayH2MaxStreams" placeholder="1024"/></div>
-              <div class="field"><label>HTTP/2 upload buffer / conn</label><input type="number" min="65536" id="cfgXrayH2UploadConn" placeholder="1048576"/></div>
-              <div class="field"><label>HTTP/2 upload buffer / stream</label><input type="number" min="32768" id="cfgXrayH2UploadStream" placeholder="262144"/></div>
               <label style="font-size:.73rem;display:flex;align-items:center;gap:5px;cursor:pointer;grid-column:1/-1"><input type="checkbox" id="cfgXrayTracePackets"/> Trace every XHTTP/mux packet <span class="hint">debug only, slows QUIC</span></label>
               <div class="card-actions" style="grid-column:1/-1;">
                 <button class="btn btn-ghost btn-sm" type="button" onclick="setXrayNativeTuningDefaults('2k')">Apply 2K defaults</button>
                 <button class="btn btn-ghost btn-sm" type="button" onclick="setXrayNativeTuningDefaults('safe')">Apply safe defaults</button>
               </div>
-              <div class="hint" style="grid-column:1/-1;margin-top:-4px;">These values are saved in the panel config and applied live on restart/reload. Go CPU threads = 0 means all detected CPU cores. No systemd Environment lines are needed.</div>
+              <div class="hint" style="grid-column:1/-1;margin-top:-4px;">Transport buffers (HTTP/2 flow control, XHTTP reorder buffer, mux/UDP buffers) are fixed to xray-core defaults and no longer tunable, so they can't be misconfigured. Go CPU threads = 0 means all detected cores. Saved in the panel config and applied live on restart/reload.</div>
             </div>
           </details>
         </div>

xray_native_tuning.go

@@ -6,53 +6,45 @@ import (
 	"time"
 )
 
-// XrayNativeTuning contains native-emulator performance limits that are edited
+// XrayNativeTuning holds the few operator-facing knobs for the in-process native
-// from the admin panel and saved in config.json under xray.native_tuning.
+// Xray. Transport-shaping parameters (HTTP/2 flow control, the XHTTP reorder
-// Values are process/runtime settings, not generated Xray JSON settings.
+// buffer, mux/UDP socket buffers) are intentionally NOT exposed: they are pinned
+// to xray-core / Go defaults so they cannot be misconfigured into breakage. Only
+// safe operational controls remain here: CPU parallelism, a global mux-session
+// DoS cap, and a packet-level trace toggle for debugging.
 type XrayNativeTuning struct {
-	// RuntimeGOMAXPROCS controls Go CPU parallelism for the in-process native Xray.
+	// RuntimeGOMAXPROCS controls Go CPU parallelism. 0 or negative = all cores.
-	// 0 or negative means use all detected CPU cores.
+	RuntimeGOMAXPROCS int `json:"runtime_gomaxprocs,omitempty"`
-	RuntimeGOMAXPROCS      int  `json:"runtime_gomaxprocs,omitempty"`
+	// MuxGlobalSessions caps total concurrent mux child sessions across every
-	MuxMaxSessions         int  `json:"mux_max_sessions,omitempty"`
+	// client connection (a DoS guard for the multi-tenant panel). 0 = default.
-	MuxGlobalSessions      int  `json:"mux_global_sessions,omitempty"`
+	MuxGlobalSessions int `json:"mux_global_sessions,omitempty"`
-	MuxUDPIdleMS           int  `json:"mux_udp_idle_ms,omitempty"`
+	// TracePackets enables very verbose per-packet XHTTP/mux logging. Debug only.
-	MuxUDPReadBuffer       int  `json:"mux_udp_read_buffer,omitempty"`
+	TracePackets bool `json:"trace_packets,omitempty"`
-	MuxUDPWriteBuffer      int  `json:"mux_udp_write_buffer,omitempty"`
-	XHTTPMaxSessions       int  `json:"xhttp_max_sessions,omitempty"`
-	XHTTPBufferedPosts     int  `json:"xhttp_buffered_posts,omitempty"`
-	H2MaxConcurrentStreams int  `json:"h2_max_concurrent_streams,omitempty"`
-	H2UploadBufferConn     int  `json:"h2_upload_buffer_conn,omitempty"`
-	H2UploadBufferStream   int  `json:"h2_upload_buffer_stream,omitempty"`
-	TracePackets           bool `json:"trace_packets,omitempty"`
 }
 
 const (
-	defaultNativeRuntimeGOMAXPROCS      = 0
+	defaultNativeRuntimeGOMAXPROCS = 0
-	defaultNativeMuxMaxSessions         = 128
+	defaultNativeMuxGlobalSessions = 32768
-	defaultNativeMuxGlobalSessions      = 32768
+
-	defaultNativeMuxUDPIdleMS           = 120000
+	// Fixed transport defaults, aligned with xray-core / Go's net/http2. These are
-	defaultNativeMuxUDPReadBuffer       = 256 * 1024
+	// deliberately not operator-tunable: wrong values silently break data flow.
-	defaultNativeMuxUDPWriteBuffer      = 256 * 1024
+	fixedNativeMuxMaxSessions    = 128        // per-connection mux child-session guard
-	defaultNativeXHTTPMaxSessions       = 16384
+	fixedNativeMuxUDPIdleMS      = 120000     // mux UDP backend idle cleanup (ms)
-	defaultNativeXHTTPBufferedPosts     = 256
+	fixedNativeMuxUDPReadBuffer  = 256 * 1024 // mux UDP socket read buffer
-	defaultNativeH2MaxConcurrentStreams = 1024
+	fixedNativeMuxUDPWriteBuffer = 256 * 1024 // mux UDP socket write buffer
-	defaultNativeH2UploadBufferConn     = 1 * 1024 * 1024
+
-	defaultNativeH2UploadBufferStream   = 256 * 1024
+	// XHTTP: max tracked sessions (DoS guard) and the packet-up reorder buffer.
+	// defaultNativeXHTTPBufferedPosts matches xray-core's scMaxBufferedPosts
+	// default; the per-inbound scMaxBufferedPosts from the config still overrides
+	// it, exactly like upstream.
+	defaultNativeXHTTPMaxSessions   = 16384
+	defaultNativeXHTTPBufferedPosts = 30
 )
 
 var (
-	nativeTuneRuntimeGOMAXPROCS      atomic.Int64
+	nativeTuneRuntimeGOMAXPROCS atomic.Int64
-	nativeTuneMuxMaxSessions         atomic.Int64
+	nativeTuneMuxGlobalSessions atomic.Int64
-	nativeTuneMuxGlobalSessions      atomic.Int64
+	nativeTuneTracePackets      atomic.Bool
-	nativeTuneMuxUDPIdleMS           atomic.Int64
-	nativeTuneMuxUDPReadBuffer       atomic.Int64
-	nativeTuneMuxUDPWriteBuffer      atomic.Int64
-	nativeTuneXHTTPMaxSessions       atomic.Int64
-	nativeTuneXHTTPBufferedPosts     atomic.Int64
-	nativeTuneH2MaxConcurrentStreams atomic.Int64
-	nativeTuneH2UploadBufferConn     atomic.Int64
-	nativeTuneH2UploadBufferStream   atomic.Int64
-	nativeTuneTracePackets           atomic.Bool
 )
 
 func init() {
@@ -67,36 +59,9 @@ func normalizeNativeXrayTuning(t *XrayNativeTuning) XrayNativeTuning {
 	if out.RuntimeGOMAXPROCS < 0 {
 		out.RuntimeGOMAXPROCS = defaultNativeRuntimeGOMAXPROCS
 	}
-	if out.MuxMaxSessions <= 0 {
-		out.MuxMaxSessions = defaultNativeMuxMaxSessions
-	}
 	if out.MuxGlobalSessions <= 0 {
 		out.MuxGlobalSessions = defaultNativeMuxGlobalSessions
 	}
-	if out.MuxUDPIdleMS <= 0 {
-		out.MuxUDPIdleMS = defaultNativeMuxUDPIdleMS
-	}
-	if out.MuxUDPReadBuffer <= 0 {
-		out.MuxUDPReadBuffer = defaultNativeMuxUDPReadBuffer
-	}
-	if out.MuxUDPWriteBuffer <= 0 {
-		out.MuxUDPWriteBuffer = defaultNativeMuxUDPWriteBuffer
-	}
-	if out.XHTTPMaxSessions <= 0 {
-		out.XHTTPMaxSessions = defaultNativeXHTTPMaxSessions
-	}
-	if out.XHTTPBufferedPosts <= 0 {
-		out.XHTTPBufferedPosts = defaultNativeXHTTPBufferedPosts
-	}
-	if out.H2MaxConcurrentStreams <= 0 {
-		out.H2MaxConcurrentStreams = defaultNativeH2MaxConcurrentStreams
-	}
-	if out.H2UploadBufferConn <= 0 {
-		out.H2UploadBufferConn = defaultNativeH2UploadBufferConn
-	}
-	if out.H2UploadBufferStream <= 0 {
-		out.H2UploadBufferStream = defaultNativeH2UploadBufferStream
-	}
 	return out
 }
 
@@ -111,31 +76,22 @@ func applyNativeXrayTuning(t *XrayNativeTuning) XrayNativeTuning {
 	}
 	runtime.GOMAXPROCS(gomax)
 	nativeTuneRuntimeGOMAXPROCS.Store(int64(gomax))
-	nativeTuneMuxMaxSessions.Store(int64(out.MuxMaxSessions))
 	nativeTuneMuxGlobalSessions.Store(int64(out.MuxGlobalSessions))
-	nativeTuneMuxUDPIdleMS.Store(int64(out.MuxUDPIdleMS))
-	nativeTuneMuxUDPReadBuffer.Store(int64(out.MuxUDPReadBuffer))
-	nativeTuneMuxUDPWriteBuffer.Store(int64(out.MuxUDPWriteBuffer))
-	nativeTuneXHTTPMaxSessions.Store(int64(out.XHTTPMaxSessions))
-	nativeTuneXHTTPBufferedPosts.Store(int64(out.XHTTPBufferedPosts))
-	nativeTuneH2MaxConcurrentStreams.Store(int64(out.H2MaxConcurrentStreams))
-	nativeTuneH2UploadBufferConn.Store(int64(out.H2UploadBufferConn))
-	nativeTuneH2UploadBufferStream.Store(int64(out.H2UploadBufferStream))
 	nativeTuneTracePackets.Store(out.TracePackets)
 	return out
 }
 
+// Operator-tunable values.
 func nativeRuntimeGOMAXPROCS() int     { return int(nativeTuneRuntimeGOMAXPROCS.Load()) }
-func nativeMuxMaxSessionLimit() int    { return int(nativeTuneMuxMaxSessions.Load()) }
 func nativeMuxGlobalSessionLimit() int { return int(nativeTuneMuxGlobalSessions.Load()) }
+func nativeTracePacketsEnabled() bool  { return nativeTuneTracePackets.Load() }
+
+// Fixed transport limits (see the const block for rationale).
+func nativeMuxMaxSessionLimit() int     { return fixedNativeMuxMaxSessions }
+func nativeMuxUDPReadBufferSize() int   { return fixedNativeMuxUDPReadBuffer }
+func nativeMuxUDPWriteBufferSize() int  { return fixedNativeMuxUDPWriteBuffer }
+func nativeXHTTPMaxSessionLimit() int   { return defaultNativeXHTTPMaxSessions }
+func nativeXHTTPBufferedPostLimit() int { return defaultNativeXHTTPBufferedPosts }
 func nativeMuxUDPIdleTimeout() time.Duration {
-	return time.Duration(nativeTuneMuxUDPIdleMS.Load()) * time.Millisecond
+	return fixedNativeMuxUDPIdleMS * time.Millisecond
 }
-func nativeMuxUDPReadBufferSize() int   { return int(nativeTuneMuxUDPReadBuffer.Load()) }
-func nativeMuxUDPWriteBufferSize() int  { return int(nativeTuneMuxUDPWriteBuffer.Load()) }
-func nativeXHTTPMaxSessionLimit() int   { return int(nativeTuneXHTTPMaxSessions.Load()) }
-func nativeXHTTPBufferedPostLimit() int { return int(nativeTuneXHTTPBufferedPosts.Load()) }
-func nativeH2MaxConcurrentStreams() int { return int(nativeTuneH2MaxConcurrentStreams.Load()) }
-func nativeH2UploadBufferConn() int     { return int(nativeTuneH2UploadBufferConn.Load()) }
-func nativeH2UploadBufferStream() int   { return int(nativeTuneH2UploadBufferStream.Load()) }
-func nativeTracePacketsEnabled() bool   { return nativeTuneTracePackets.Load() }

xray_xhttp.go

@@ -99,11 +99,9 @@ func mergeNativeXHTTPSettings(primary, fallback nativeXHTTPSettingsJSON) nativeX
 
 func (ib *nativeInbound) serveXHTTPListener(ln net.Listener) {
 	defer xrayRecover(fmt.Sprintf("native xray XHTTP listener inbound=%q addr=%s", ib.tag, ln.Addr()))
-	h2s := &http2.Server{
+	// Match xray-core: let net/http's HTTP/2 use its own defaults for flow
-		MaxConcurrentStreams:         uint32(nativeH2MaxConcurrentStreams()),
+	// control, stream limits and upload buffers instead of overriding them.
-		MaxUploadBufferPerConnection: int32(nativeH2UploadBufferConn()),
+	h2s := &http2.Server{}
-		MaxUploadBufferPerStream:     int32(nativeH2UploadBufferStream()),
-	}
 	handler := http.Handler(ib)
 	// Official Xray accepts plaintext HTTP/1.1 and h2c on non-TLS XHTTP
 	// listeners, and negotiates h2/http1 through ALPN on TLS listeners. Without