ipfw2 (was Re: Hard-coded M_* flags)

[YONETANI Tomokazu]

On Sun, Jun 11, 2006 at 08:29:37PM +0200, joerg at xxxxxxxxxxxxxxxxx wrote:
> One thing you should look at is whether or not the flag needs to be kept
> when copying the mbuf. I don't know whether it is an issue for this
> application, but it might need special handling.

Good catch, it must be copied, but apparently the original ip_fw2.c code
we inherited from FreeBSD 4.8 didn't:
  http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/sys/mbuf.h?rev=1.128&content-type=text/x-cvsweb-markup

Since M_SKIP_FIREWALL is set only on pkthdr, and duplication of pkthdr
is performed by structure copy of m_pkthdr(which contains fw_flags),
the patch should retain the current behavior.