It goes more into a preventative strategy for me. Once I have seen a child bites-- I try to see what triggers it.
You seem to indicate your son does it when he is frustrated or because of a toy so I would watch them like a hawk during play time and try to swoop in if you see your son about to bite.
Then I make eye contact and say a stern/angry NO ! We don't bite and then I explain that it hurts and that teeth are not for biting
I would then redirect him.

If he bites and you don't notice until the action has happened and he has hurt the other child I would say the same verbage but give a 2 min time out. after the time out I would again have a stern reminder that he is not allowed to bite.

I don't think there is a fast easy cure. It is going to mean you really watching and trying to catch him before he does it and showing a negative reaction to his behaviour and showing him that it does not get the results he wants