tcpdump privilege separation

[Andre Nathan]

Hi

I have addapted OpenBSD's work to provide privilege separation for tcpdump
([1], [2]) to DragonFly.

The patches are available at [3]. Beside's applying the patches, you'll
need to add the ``_tcpdump'' user on your system.

These patches break the buildwolrd on usr.sbin/ndp, because it relies on
the gmt2local.{c,h} files from tcpdump. I took the easy way and just
copied the original ones to the ndp directory, and edited the Makefile to
add the new files and remove the now unnecessary include directories.

Best regards,
Andre

[1]http://marc.theaimsgroup.com/?l=openbsd-cvs&m=107531986114887&w=2
[2]http://marc.theaimsgroup.com/?l=openbsd-cvs&m=106684834031056&w=2
[3]http://andre.people.digirati.com.br/dragonfly/tcpdump-privsep/