and "pass-filter" and "inbound" and "outbound" qualifiers in the filter
expression, use new "active-filter-in", "active-filter-out", "pass-filter-in",
and "pass-filter-out" without these qualifiers.
This is necessary due to the horrible, awful way "inbound" and "outbound"
were specified for the filter programs when a packet was passed through them.
Basically, the "address" byte in the serial PPP header was overwritten with
a value to indicate the direction. However, the "address" byte doesn't even
exist on PPP headers for all other PPP encaps! So, this old method worked
only for serial encaps, and corrupted packets for all others (PPPoE, ATM, etc.)
device and a printable "external name" (name + unit number), thus eliminating
if_name and if_unit. Updated interface to (*if_watchdog)() and (*if_reset)()
to take a struct ifnet *, rather than a unit number.
trivial multicast support, and support for xon/xoff output flow
control to the PPP subsystem. Fixed several bugs, including making
the accumulation and resetting of statistics more consistent. State
for the VJ compressor is now dynamically allocated.
improvements. The PPP kernel code is now split into if_ppp.c,
containing generic PPP support, and ppp_tty.c, which specifically
supports PPP on async tty devices (as a line discipline). This is
so that other devices can be supported without making them look
like ttys.