Complete list of subnets?

[==Troy==]

I am working on a subnet bans patch (in parallel with a lot of other stuff). And I would like to ask if there is any source, preferably up-to-date source, which can provide subnets (to the smallest sets) ? Would be perfect if they were in the form  XXX.XXX.XXX.XXX/YY but that does not matter much. It has to be a list of them, rather than a search ip - find subnet service.

Thank you in advance ).