Current versions of both FreeBSD and NetBSD include up-to-date ppp
code in the kernel sources.  You may have to edit your kernel
configuration file and recompile your kernel to get the ppp driver
(line-discipline) code compiled into the kernel.  NetBSD-current
(at least) also includes a recent version of pppd in /usr/src/sbin/pppd.
The following comments apply to 386bsd and older versions of FreeBSD
and NetBSD.

The following kernel files must be modified in order to make ppp work.
I've included both the final files and diffs from the "patchkit 0.2.1"
release.

	/sys/conf/files		- add pp pseudo device
	/sys/sys/ioctl.h	- add ioctl's for interface
	/sys/net/if.c		- add ioctl's
	/sys/net/if_types.h	- add ppp interface type
	/sys/kern/init_main.c	- init ppp
	/sys/kern/tty_conf.c	- add ppp line discipline
	/sys/kern/tty_pty.c	- pass ioctl's

These files must be added to the kernel

	/sys/net/if_ppp.c	- pseudo device/line discipline
	/sys/net/if_ppp.h

The include file "if_ppp.h" is in ../net as it's used by pppd as 
well as the kernel.

The file "386bsd.diff" contains diffs to the existing files.
