NAT (ipfw/natd) broken in latest -CURRENT

[Max Laier]

On Friday 19 December 2008 02:41:02 Li, Qing wrote:
> I have checked in a fix for this issue (r186308), which turned out to
> be a problem in the ppp module. The ppp module updates the p2p host
> route that was installed during the tunnel configuration, however, the
> ppp code always set the RTF_GATEWAY flag. The patch has been verified to
> be working by Joe.
>
> Please let me know if you run into any other issue.

There has been a similar report in freebsd-net@ just recently, OP CC'ed.  
Denis, can you check if the fix quoted above fixes your problem?

> Thanks,
>
> -- Qing
>
> > -----Original Message-----
> > From: Joe Marcus Clarke [mailto:marcus at freebsd.org]
> > Sent: Thursday, December 18, 2008 2:02 PM
> > To: Li, Qing
> > Cc: current
> > Subject: RE: NAT (ipfw/natd) broken in latest -CURRENT
> >
> > On Thu, 2008-12-18 at 12:53 -0800, Li, Qing wrote:
> > > Hi Joe,
> > >
> > > I have been trying to recreate your problem but my setup seem to
> > > work. I then noticed in your original netstat output the p2p
> > > host route installed by the tunnel interface has the "G" flag
> > > set. This will certainly cause a routing problem because that
> > > route is not an indirect route. I modified the kernel code to
> >
> > simulate
> >
> > > this condition and I do see the error on output, which is expected.
> > >
> > > I assume this problem is consistently reproducible in your setup ?
> >
> > Absolutely.  Every time I setup the p2p tunnel with the non-proxy ARP
> > address range.  Traffic flows outbound, but never inbound.  Your
> > analysis sounds correct.  The kernel doesn't know the interface on
> > which
> > to encapsulate the return traffic.
> >
> > Joe
> >
> > > -- Qing
> > >
> > > > -----Original Message-----
> > > > From: owner-freebsd-current at freebsd.org [mailto:owner-freebsd-
> > > > current at freebsd.org] On Behalf Of Joe Marcus Clarke
> > > > Sent: Tuesday, December 16, 2008 5:20 PM
> > > > To: current
> > > > Subject: NAT (ipfw/natd) broken in latest -CURRENT
> > > >
> > > > I just upgraded my i386 -CURRENT box from November 14 to today,
>
> and
>
> > > now
> > >
> > > > my SSH-over-PPP VPN tunnel no longer works.  I did some packet
> > >
> > > captures,
> > >
> > > > and it appears that NAT is no longer working.  If I send a telnet
> > > > packet
> > > > from my client side over the PPP tunnel, I see the SYN go out on
> >
> > the
> >
> > > > server side network properly translated.  The destination host
>
> ACKs
>
> > > > correctly, but the ACK never goes back across the tunnel.  It's as
> >
> > if
> >
> > > > natd is no longer translating the packet on the inbound path.
> >
> > Besides
> >
> > > > the upgrade, nothing has changed in my environment.
> > > >
> > > > My ipfw show looks like:
> > > >
> > > > 00050 22974 4677637 divert 8668 ip4 from any to any via em0
> > > > 00100   194   20696 allow ip from any to any via lo0
> > > > 00200     0       0 deny ip from any to 127.0.0.0/8
> > > > 00300     0       0 deny ip from 127.0.0.0/8 to any
> > > > 65000 24714 4934785 allow ip from any to any
> > > > 65535     5     396 deny ip from any to any
> > > >
> > > > I am running natd as:
> > > >
> > > > /sbin/natd -s -m -skinny_port 2000 -n em0
> > > >
> > > > The ifconfig for my tunnel interface is:
> > > >
> > > > tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu
> >
> > 1300
> >
> > > > 	inet 10.1.1.1 --> 10.1.1.76 netmask 0xffffff00
> > > > 	inet6 fe80::211:11ff:fe10:461e%tun0 prefixlen 64 scopeid 0x5
> > > > 	Opened by PID 8018
> > > >
> > > > My netstat on the server side looks like:
> > > >
> > > > Internet:
> > > > Destination        Gateway            Flags    Refs      Use
>
> Netif
>
> > > > Expire
> > > > default            172.18.254.1       UGS         0    46685
>
> em0
>
> > > > 10.1.1.76          link#5             UGH         0     1735
>
> tun0
>
> > > > 127.0.0.1          link#3             UH          0     1171
>
> lo0
>
> > > > 172.18.254.0/24    link#1             U           0        0
>
> em0
>
> > > > 172.18.254.237/32  link#1             U           0        8
>
> em0
>
> > > > The server's uname is:
> > > >
> > > > FreeBSD jclarke-pc.cisco.com 8.0-CURRENT FreeBSD 8.0-CURRENT #130:
> >
> > Tue
> >
> > > > Dec 16 15:42:09 EST 2008
> > > > marcus at jclarke-pc.cisco.com:/usr/obj/usr/src/sys/JCLARKE-PC  i386
> > > >
> > > > The previous, working uname was:
> > > >
> > > > FreeBSD 8.0-CURRENT #129: Fri Nov 14 13:51:50 EST 2008
> > > >     marcus at jclarke-pc.cisco.com:/usr/obj/usr/src/sys/JCLARKE-PC
> > > >
> > > > Joe
> > > >
> > > > --
> > > > Joe Marcus Clarke
> > > > FreeBSD GNOME Team      ::      gnome at FreeBSD.org
> > > > FreeNode / #freebsd-gnome
> > > > http://www.FreeBSD.org/gnome
> >
> > --
> > Joe Marcus Clarke
> > FreeBSD GNOME Team      ::      gnome at FreeBSD.org
> > FreeNode / #freebsd-gnome
> > http://www.FreeBSD.org/gnome
>
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