pfil information, instead, struct protosw now contains a structure
which caontains list heads, etc. The per-protosw pfil struct is passed
to pfil_hook_get(), along with an in/out flag to get the head of the
relevant filter list. This has been done for only IPv4 and IPv6, at
present, with these patches only enabling filtering for IPPROTO_IP and
IPPROTO_IPV6, although it is possible to have tcp/udp, etc, dedicated
filters now also. The ipfilter code has been updated to only filter
IPv4 packets - next major release of ipfilter is required for ipv6.
fd7edad6c3