Date: Wed, 16 Aug 2017 13:08:47 -0700 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Emmanuel Vadot <manu@bidouilliste.com> Cc: Emmanuel Vadot <manu@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r320944 - head/etc/rc.d Message-ID: <20170816200847.GJ1113@FreeBSD.org> In-Reply-To: <20170816160850.1b695e1e292f46f892301db5@bidouilliste.com> References: <201707131340.v6DDeIE9086139@repo.freebsd.org> <20170815224929.GC1113@FreeBSD.org> <20170816160850.1b695e1e292f46f892301db5@bidouilliste.com>
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Emmanuel, On Wed, Aug 16, 2017 at 04:08:50PM +0200, Emmanuel Vadot wrote: E> > It could be that using "netgraph" action instead of "ngtee" and then E> > returning packet back from netgraph to ipfw would show lower overhead. E> > However, this setup is definitely going to be less robust and more prone E> > to bugs in case of complex ipfw configurations. E> E> I should have been more clear, I didn't mean that it would have less E> overhead in memory but in process time. E> Reading the source code I saw that ngtee simply m_dup the packet E> and then ipfw directly continue with the original one, so it seems to E> me that this would be the the fastest way to process packets. Allocating memory, doing a memory copy, and freeing memory is also process time. E> Could you expand on "less robust and more prone to bugs" for the E> "netgraph" case ? The "netgraph" action send packet to netgraph allocating a tag so that if later the ng_ipfw node receives the tagged packet back, it can inject it to the next rule after the rule with "netgraph" action. This all is documented. -- Totus tuus, Glebius.
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