- All packets are passed to PFIL_HOOKS as they come off the wire, i.e.
fields in protocol headers in network order, etc.
- Allow for multiple hooks to be registered, using a "key" and a "dlt".
The "dlt" is a BPF data link type, indicating what type of header is
present.
- INET and INET6 register with key == AF_INET or AF_INET6, and
dlt == DLT_RAW.
- PFIL_HOOKS now take an argument for the filter hook, and mbuf **,
an ifnet *, and a direction (PFIL_IN or PFIL_OUT), thus making them
less IP (really, IP Filter) centric.
Maintain compatibility with IP Filter by adding wrapper functions for
IP Filter.
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