Be paranoid and check that the prefix length in addresses from
used_addr4_list are not zero (they shouldn't be) and that address family
is AF_INET (it should be), mainly to quiet coverity warnings:
While there also fix one line's indentation.
At the end of ip_pool_select_addr4() we'd check if the selected address
is equal to the subnet address and increment it by 1 to produce a valid
host address for the AP. That check was always correct only with 24-bit
prefix, extend it to actually use the prefix-dependent mask instead of
0xff. Fixes a testAP failure triggered 50% of the times because the
netmask is 28 bit long there.
Add the ip_pool_select_addr4 function to select a random subnet of requested
size from an address space defined by a string list (for use with the
AP profile [IPv4].Address and the global [IPv4].APAddressPool settings),
avoiding those subnets that conflict with subnets in use. We take care
to give a similar weight to all subnets contained in the specified
ranges regardless of how many ranges contain each, basically so that
overlapping ranges don't affect the probabilities (debatable.)
Add the ip-pool submodule that tracks IPv4 addresses in use on the
system for use when selecting the address for a new AP. l_rtnl_address
is used internally because if we're going to return l_rtnl_address
objects it would be misleading if we didn't fill in all of their
properties like flags etc.
