Ukranian Military, Why Can't They Attack Russia?

Ukrane allegedly fired some artillery into russian territory. Why is ukraine waiting so long to attack russia? Who made the rule that only russia can attack inside ukraine? Is it because put will get mad? I mean, he act acts like he's kind of mad right now, little bit. Are you telling me that they can't even get a terrorist attack into moscow? Not recommending it, not recommending it. But i'm wondering about the strategy. How do you send the message? That's how i'd send it if i were an unscrupulous leader and didn't care about casualties. It wouldn't be straightforward, but, ah, i mean,