{"record":{"id":"b8ee8e56e6d40ccc","repo":"XTLS/Xray-core","slug":"invalid-xray-tun-fd","errorCode":null,"errorMessage":"invalid xray.tun.fd","messagePattern":"invalid xray\\.tun\\.fd","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"proxy/tun/tun_linux.go","lineNumber":81,"sourceCode":"\tlinuxTun := &LinuxTun{\n\t\ttunFd:   tunFd,\n\t\ttunLink: tunLink,\n\t\toptions: options,\n\t\townsTun: true,\n\t}\n\n\treturn linuxTun, nil\n}\n\nfunc openFromEnv(expectedName string) (int, netlink.Link, bool, error) {\n\tfdStr := platform.NewEnvFlag(platform.TunFdKey).GetValue(func() string { return \"\" })\n\tif fdStr == \"\" {\n\t\treturn -1, nil, false, nil\n\t}\n\n\tfd, err := strconv.Atoi(fdStr)\n\tif err != nil {\n\t\treturn -1, nil, true, errors.New(\"invalid \", platform.TunFdKey).Base(err)\n\t}\n\tif fd < 3 {\n\t\treturn -1, nil, true, errors.New(\"invalid \", platform.TunFdKey, \": file descriptor must be >= 3\")\n\t}\n\n\tifr, err := unix.NewIfreq(\"\")\n\tif err != nil {\n\t\treturn -1, nil, true, err\n\t}\n\tif err = unix.IoctlIfreq(fd, unix.TUNGETIFF, ifr); err != nil {\n\t\treturn -1, nil, true, err\n\t}\n\n\tflags := ifr.Uint16()\n\tif flags&unix.IFF_TUN == 0 {\n\t\treturn -1, nil, true, errors.New(\"invalid \", platform.TunFdKey, \": file descriptor is not a TUN device\")\n\t}\n\tif flags&unix.IFF_NO_PI == 0 {","sourceCodeStart":63,"sourceCodeEnd":99,"githubUrl":"https://github.com/XTLS/Xray-core/blob/7d214f8b094f75322fa3990f8aadad1c912f24f5/proxy/tun/tun_linux.go#L63-L99","documentation":"Error \"invalid xray.tun.fd\" thrown in XTLS/Xray-core.","triggerScenarios":"Thrown at proxy/tun/tun_linux.go:81 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"7d214f8b094f75322fa3990f8aadad1c912f24f5","analyzedAt":"2026-08-15T14:26:24.325Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}