fix(xhttp): stop injecting scMaxEachPostBytes/scMinPostsIntervalMs defaults (#5141)

The panel seeded xhttp configs with scMaxEachPostBytes=1000000 and
scMinPostsIntervalMs=30 — xray-core''s own defaults — and emitted them
into every generated config and share link. The literal
scMinPostsIntervalMs=30 is a stable DPI fingerprint that Russia''s TSPU
keys on to block connections on mobile networks.

New configs no longer seed these values (empty schema/template defaults,
so xray-core applies its internal defaults). For configs already stored
with the old defaults, the link/subscription builders now drop values
equal to xray-core''s defaults instead of advertising them — covering
panel share links, the raw subscription, and the JSON subscription
without requiring every inbound to be re-saved. Non-default values the
user set deliberately are still emitted.

internal/sub/json_service.go

@@ -217,6 +217,15 @@ func (s *SubJsonService) streamData(stream string) map[string]any {
 			delete(xhttp, "scMaxBufferedPosts")
 			delete(xhttp, "scStreamUpServerSecs")
 			delete(xhttp, "serverMaxHeaderBytes")
+			// Values matching xray-core's own defaults stay off the wire:
+			// old panels seeded them into every stored config and the
+			// literal scMinPostsIntervalMs=30 is a DPI fingerprint (#5141).
+			if v, _ := xhttp["scMaxEachPostBytes"].(string); v == "" || v == "1000000" {
+				delete(xhttp, "scMaxEachPostBytes")
+			}
+			if v, _ := xhttp["scMinPostsIntervalMs"].(string); v == "" || v == "30" {
+				delete(xhttp, "scMinPostsIntervalMs")
+			}
 		}
 	}
 	return streamSettings

internal/sub/service.go

@@ -1661,8 +1661,16 @@ func buildXhttpExtra(xhttp map[string]any) map[string]any {
 		"uplinkDataPlacement", "uplinkDataKey",
 		"scMaxEachPostBytes", "scMinPostsIntervalMs",
 	}
+	// Values matching xray-core's own defaults are redundant on the wire and
+	// the literal scMinPostsIntervalMs=30 is a known DPI fingerprint (#5141).
+	// Old panels seeded these defaults into every xhttp inbound, so filter
+	// them here instead of requiring every stored config to be re-saved.
+	coreDefaults := map[string]string{
+		"scMaxEachPostBytes":   "1000000",
+		"scMinPostsIntervalMs": "30",
+	}
 	for _, field := range stringFields {
-		if v, ok := xhttp[field].(string); ok && len(v) > 0 {
+		if v, ok := xhttp[field].(string); ok && len(v) > 0 && v != coreDefaults[field] {
 			extra[field] = v
 		}
 	}

internal/util/link/outbound.go

@@ -545,9 +545,11 @@ func buildStream(network, security string) map[string]any {
 	case "httpupgrade":
 		stream["httpupgradeSettings"] = map[string]any{"path": "/", "host": "", "headers": map[string]any{}}
 	case "xhttp":
+		// No scMaxEachPostBytes/scMinPostsIntervalMs seed: xray-core's own
+		// defaults apply, and the literal values fingerprint traffic (#5141).
 		stream["xhttpSettings"] = map[string]any{
 			"path": "/", "host": "", "mode": "auto", "headers": map[string]any{},
-			"xPaddingBytes": "100-1000", "scMaxEachPostBytes": "1000000",
+			"xPaddingBytes": "100-1000",
 		}
 	default:
 		stream["tcpSettings"] = map[string]any{"header": map[string]any{"type": "none"}}