Add one metrics field to record the cause of DNS query internal error

    RC_EAI_BADHINTS = 12;

    RC_EAI_PROTOCOL = 13;

    RC_EAI_OVERFLOW = 14;

    RC_RESOLV_INTERNAL_ERROR = 254;

    RC_RESOLV_TIMEOUT = 255;

    RC_EAI_MAX = 256;

}

    CS_SKIP = 3;

}

// The enum LinuxErrno is defined in the following 2 files.

// 1. bionic/libc/kernel/uapi/asm-generic/errno-base.h

// 2. bionic/libc/kernel/uapi/asm-generic/errno.h

enum LinuxErrno {

    SYS_UNKNOWN = 0;

    SYS_EPERM = 1;              // Not super-user

    SYS_ENOENT = 2;             // No such file or directory

    SYS_ESRCH = 3;              // No such process

    SYS_EINTR = 4;              // Interrupted system call

    SYS_EIO = 5;                // I/O error

    SYS_ENXIO = 6;              // No such device or address

    SYS_E2BIG = 7;              // Arg list too long

    SYS_ENOEXEC = 8;            // Exec format error

    SYS_EBADF = 9;              // Bad file number

    SYS_ECHILD = 10;            // No children

    SYS_EAGAIN = 11;            // No more processes

    SYS_ENOMEM = 12;            // Not enough core

    SYS_EACCES = 13;            // Permission denied

    SYS_EFAULT = 14;            // Bad address

    SYS_ENOTBLK = 15;           // Block device required

    SYS_EBUSY = 16;             // Mount device busy

    SYS_EEXIST = 17;            // File exists

    SYS_EXDEV = 18;             // Cross-device link

    SYS_ENODEV = 19;            // No such device

    SYS_ENOTDIR = 20;           // Not a directory

    SYS_EISDIR = 21;            // Is a directory

    SYS_EINVAL = 22;            // Invalid argument

    SYS_ENFILE = 23;            // Too many open files in system

    SYS_EMFILE = 24;            // Too many open files

    SYS_ENOTTY = 25;            // Not a typewriter

    SYS_ETXTBSY = 26;           // Text file busy

    SYS_EFBIG = 27;             // File too large

    SYS_ENOSPC = 28;            // No space left on device

    SYS_ESPIPE = 29;            // Illegal seek

    SYS_EROFS = 30;             // Read only file system

    SYS_EMLINK = 31;            // Too many links

    SYS_EPIPE = 32;             // Broken pipe

    SYS_EDOM = 33;              // Math arg out of domain of func

    SYS_ERANGE = 34;            // Math result not representable

    SYS_EDEADLOCK = 35;         // File locking deadlock error

    SYS_ENAMETOOLONG = 36;      // File or path name too long

    SYS_ENOLCK = 37;            // No record locks available

    SYS_ENOSYS = 38;            // Function not implemented

    SYS_ENOTEMPTY = 39;         // Directory not empty

    SYS_ELOOP = 40;             // Too many symbolic links

    SYS_ENOMSG = 42;            // No message of desired type

    SYS_EIDRM = 43;             // Identifier removed

    SYS_ECHRNG = 44;            // Channel number out of range

    SYS_EL2NSYNC = 45;          // Level 2 not synchronized

    SYS_EL3HLT = 46;            // Level 3 halted

    SYS_EL3RST = 47;            // Level 3 reset

    SYS_ELNRNG = 48;            // Link number out of range

    SYS_EUNATCH = 49;           // rotocol driver not attached

    SYS_ENOCSI = 50;            // No CSI structure available

    SYS_EL2HLT = 51;            // Level 2 halted

    SYS_EBADE = 52;             // Invalid exchange

    SYS_EBADR = 53;             // Invalid request descriptor

    SYS_EXFULL = 54;            // Exchange full

    SYS_ENOANO = 55;            // No anode

    SYS_EBADRQC = 56;           // Invalid request code

    SYS_EBADSLT = 57;           // Invalid slot

    SYS_EBFONT = 59;            // Bad font file fmt

    SYS_ENOSTR = 60;            // Device not a stream

    SYS_ENODATA = 61;           // No data (for no delay io)

    SYS_ETIME = 62;             // Timer expired

    SYS_ENOSR = 63;             // Out of streams resources

    SYS_ENONET = 64;            // Machine is not on the network

    SYS_ENOPKG = 65;            // Package not installed

    SYS_EREMOTE = 66;           // The object is remote

    SYS_ENOLINK = 67;           // The link has been severed

    SYS_EADV = 68;              // Advertise error

    SYS_ESRMNT = 69;            // Srmount error

    SYS_ECOMM = 70;             // Communication error on send

    SYS_EPROTO = 71;            // Protocol error

    SYS_EMULTIHOP = 72;         // Multihop attempted

    SYS_EDOTDOT = 73;           // Cross mount point (not really error)

    SYS_EBADMSG = 74;           // Trying to read unreadable message

    SYS_EOVERFLOW = 75;         // Value too large for defined data type

    SYS_ENOTUNIQ = 76;          // Given log. name not unique

    SYS_EBADFD = 77;            // f.d. invalid for this operation

    SYS_EREMCHG = 78;           // Remote address changed

    SYS_ELIBACC = 79;           // Can't access a needed shared lib

    SYS_ELIBBAD = 80;           // Accessing a corrupted shared lib

    SYS_ELIBSCN = 81;           // .lib section in a.out corrupted

    SYS_ELIBMAX = 82;           // Attempting to link in too many libs

    SYS_ELIBEXEC = 83;          // Attempting to exec a shared library

    SYS_EILSEQ = 84;

    SYS_ERESTART = 85;

    SYS_ESTRPIPE = 86;

    SYS_EUSERS = 87;

    SYS_ENOTSOCK = 88;          // Socket operation on non-socket

    SYS_EDESTADDRREQ = 89;      // Destination address required

    SYS_EMSGSIZE = 90;          // Message too long

    SYS_EPROTOTYPE = 91;        // Protocol wrong type for socket

    SYS_ENOPROTOOPT = 92;       // Protocol not available

    SYS_EPROTONOSUPPORT = 93;   // Unknown protocol

    SYS_ESOCKTNOSUPPORT = 94;   // Socket type not supported

    SYS_EOPNOTSUPP = 95;        // Operation not supported on transport endpoint

    SYS_EPFNOSUPPORT = 96;      // Protocol family not supported

    SYS_EAFNOSUPPORT = 97;      // Address family not supported by protocol family

    SYS_EADDRINUSE = 98;        // Address already in use

    SYS_EADDRNOTAVAIL = 99;     // Address not available

    SYS_ENETDOWN = 100;         // Network interface is not configured

    SYS_ENETUNREACH = 101;      // Network is unreachable

    SYS_ENETRESET = 102;

    SYS_ECONNABORTED = 103;     // Connection aborted

    SYS_ECONNRESET = 104;       // Connection reset by peer

    SYS_ENOBUFS = 105;          // No buffer space available

    SYS_EISCONN = 106;          // Socket is already connected

    SYS_ENOTCONN = 107;         // Socket is not connected

    SYS_ESHUTDOWN = 108;        // Can't send after socket shutdown

    SYS_ETOOMANYREFS = 109;

    SYS_ETIMEDOUT = 110;        // Connection timed out

    SYS_ECONNREFUSED = 111;     // Connection refused

    SYS_EHOSTDOWN = 112;        // Host is down

    SYS_EHOSTUNREACH = 113;     // Host is unreachable

    SYS_EALREADY = 114;         // Socket already connected

    SYS_EINPROGRESS = 115;      // Connection already in progress

    SYS_ESTALE = 116;

    SYS_EUCLEAN = 117;

    SYS_ENOTNAM = 118;

    SYS_ENAVAIL = 119;

    SYS_EISNAM = 120;

    SYS_EREMOTEIO = 121;

    SYS_EDQUOT = 122;

    SYS_ENOMEDIUM = 123;        // No medium (in tape drive)

    SYS_EMEDIUMTYPE = 124;

    SYS_ECANCELED = 125;

    SYS_ENOKEY = 126;

    SYS_EKEYEXPIRED = 127;

    SYS_EKEYREVOKED = 128;

    SYS_EKEYREJECTED = 129;

    SYS_EOWNERDEAD = 130;

    SYS_ENOTRECOVERABLE = 131;

    SYS_ERFKILL = 132;

    SYS_EHWPOISON = 133;

}

message DnsQueryEvent {

    optional NsRcode rcode = 1;

    optional bool connected = 8;

    optional int32 latency_micros = 9;

    optional LinuxErrno linux_errno = 10;

}

message DnsQueryEvents {