Deterministic lockup / panic in networking stack with ipfw /
natd enabled on recent amd64 STABLE / CURRENT
yanefbsd at gmail.com
Sat Jul 3 03:53:36 UTC 2010
On Fri, Jul 2, 2010 at 8:26 PM, Ian Smith <smithi at nimnet.asn.au> wrote:
> On Sat, 3 Jul 2010, Ian Smith wrote:
> > On Tue, 15 Jun 2010, Garrett Cooper wrote:
> > > Hi,
> > > I'm experiencing a deterministic situation on a development box I
> > > manage when I do the following to enable ipfw and natd to bridge a
> > > network with two bce(4) enabled NICs, where if I do the following
> > > steps below, then try to push a few tcp frames through, the kernel
> > > either hardlocks, or panics in the bce(4) code, ipfw(4) code or
> > > networking stack code.
> > > My kernel is relatively vanilla (I just turned off a number of
> > > drivers that I don't use because the hardware support isn't there),
> > > and all of the networking options available in GENERIC are enabled as
> > > well. I have ipfw, ipfw_nat, and libalias built as modules, along with
> > > bce and em.
> > > I've included the stats on the machine. Note that it is a dual
> > > SMT-enabled quad core machine with 8GB of RAM. I haven't done anything
> > > to pimp the box settings via make.conf whatsoever. I would provide a
> > > crashdump, but dumpon is broken on the box (which is extremely
> > > annoying). Please note that pf doesn't have any issues pushing packets
> > > with similar rules.
> > > This has occurred on both 8-STABLE (r209169), and 9-CURRENT (r208809).
> > > Here's the manual procedure for reproducing the issue:
> > >
> > > # Do the following steps (this isn't automated apparently as it
> > > completely blocks off a running box, when using ipfw restart is run).
> > >
> > > # Copy the 8.0-RELEASE copy of rc.firewall over
> > > cp -p /usr/src/etc/rc.firewall /etc
> > >
> > > # Make sure you have access via ssh being redirected via natd.
> > > echo "redirect_port tcp 192.168.10.1:22 22" > /etc/natd.conf
> > >
> > > # Enable all of the required services and knobs
> > > cat >> /etc/rc.conf <<EOF
> > > firewall_enable="YES"
> > > firewall_logging="YES"
> > > firewall_nat_enable="YES"
> > > firewall_nat_interface="bce1"
> > > firewall_type="open"
> > > gateway_enable="YES"
> > > ipfw_enable="YES"
> > > natd_enable="YES"
> > > natd_interface="bce1"
> > > natd_flags="-dynamic -d -m"
> > > EOF
> > Garrett I missed this earlier; here from your ref in the TSO thread.
> > If you enable both firewall_nat and natd as above, on that config you
> > should have wound up with two of ipfw rule 50, like
> > 50 divert 8668 ip4 from any to any via bce1
> > 50 nat 123 ip4 from any to any via bce1
> > but I don't think you really wanted to run natd then firewall_nat again
> > like that?
> Oh, sorry .. that's not right; I quite forgot the discussions in ipfw@
> about this a while ago, until I re-browsed natd(8):
> After translation by natd, packets re-enter the firewall at the rule
> number following the rule number that caused the diversion (not the
> next rule if there are several at the same number).
> so in this case only natd should be invoked and the ipfw nat skipped.
> > Also I'm pretty sure you'd need to include '-f /etc/natd.conf' in your
> > natd_flags for your redirect_port config, here's no default configfile
> > for natd (AFAIK)
> I think that's right - or you can specify -redirect_port in natd_flags.
> > I guess rc.firewall ought to be checking that natd_enable and
> > firewall_nat_enable aren't both YES ..
> .. and that becomes irrelevant, though it's still an ambiguous config.
I'll look into this more closely on Sunday when I come in to repro
Thanks for the feedback :)!
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