def isReachableByEcho(ip: String, timeout: Int): Boolean = {
    Zone { implicit z =>
      val cIP   = toCString(ip)
      var hints = stackalloc[addrinfo]
      var ret   = z.alloc(sizeof[addrinfo]).cast[Ptr[addrinfo]]

      string.memset(hints.cast[Ptr[Byte]], 0, sizeof[addrinfo])
      hints.ai_family = AF_UNSPEC
      hints.ai_protocol = 0
      hints.ai_addr = null
      hints.ai_flags = 4 // AI_NUMERICHOST
      hints.ai_socktype = SOCK_STREAM
      hints.ai_next = null
      ret.ai_next = null

      if (getaddrinfo(cIP, toCString("7"), hints, ret) != 0) {
        return false
      }

      val sock = socket(ret.ai_family, SOCK_STREAM, ret.ai_protocol);
      if (sock < 0) {
        freeaddrinfo(ret)
        return false
      }
      val connectRes = connect(sock, ret.ai_addr, ret.ai_addrlen)
      if (connectRes < 0) {
        close(sock)
        freeaddrinfo(ret)
        return false
      }

      freeaddrinfo(ret)

      val sentBytes = send(sock, toCString("echo"), 4, 0)
      if (sentBytes < 4) {
        close(sock)
        return false
      }

      val rfds = stackalloc[fd_set](FD_SETSIZE / sizeof[CInt])
      FD_ZERO(rfds)
      FD_SET(sock, rfds)

      val time = stackalloc[timeval]
      time.tv_sec = timeout / 1000
      time.tv_usec = (timeout % 1000) * 1000

      // name conflict
      var res =
        scalanative.posix.sys.select.select(sock + 1, rfds, null, null, time)

      val buf      = stackalloc[CChar](5)
      val recBytes = recv(sock, buf, 5, 0)
      if (recBytes < 4) {
        close(sock)
        return false
      }

      close(sock)
    }
    true
  }