Given an IPv4 address and prefix for a shared config, figure out
the DHCP address range automatically.  To keep things simple we
allow a max of 252 addresses (not including network address,
broadcast address, and the hotspot) no matter what prefix you use,
so if the address is 10.0.10.1, you still only get a range of
10.0.10.2 -> 10.0.10.254.

But we also leave some addresses available above the host address
for static stuff, like we did before.  This is done on a sliding
scale from 0 to 8 addresses, where about 1/10th the number of
available addresses are reserved.

https://bugzilla.gnome.org/show_bug.cgi?id=675973