Date: Fri, 29 Apr 2011 11:28:07 -0700 From: YongHyeon PYUN <pyunyh@gmail.com> To: freebsd-net@freebsd.org Subject: Re: collisions on tun interfaces ... Message-ID: <20110429182807.GA21084@michelle.cdnetworks.com> In-Reply-To: <20110429095231.GA17786@relay.ibs.dn.ua> References: <201104290001.p3T01EvQ082443@artema.vpn.ibs> <20110429095231.GA17786@relay.ibs.dn.ua>
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On Fri, Apr 29, 2011 at 12:52:31PM +0300, Zeus V Panchenko wrote:
> Hi,
>
> may somebody epxplain it for me, what can cause collisions on tun
> interfaces created by ppp(8) and openvpn?
>
> > uname -a
> FreeBSD 8.2-STABLE #0 i386
>
> > netstat -i
> Name Mtu Network Address Ipkts Ierrs Idrop Opkts Oerrs Coll
> tun0 1492 <Link#7> 18940349 0 0 15737760 0 45668
> tun0 1492 A.B.C.D A-B-C-D.domain 15623965 - - 12429351 - -
> tun1 1500 <Link#8> 12721670 0 0 9957662 0 11161
> tun1 1500 E.F.G.H E-F-G-H.vpn 6454 - - 445751 - -
>
>
> rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> options=3808<VLAN_MTU,WOL_UCAST,WOL_MCAST,WOL_MAGIC>
> ether 00:30:4f:67:cf:81
> media: Ethernet autoselect (100baseTX <full-duplex>)
> status: active
> tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1492
> options=80000<LINKSTATE>
> inet A.B.C.D --> A1.B1.C1.D1 netmask 0xffffffff
> Opened by PID 3943
> tun1: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1500
> options=80000<LINKSTATE>
> inet E.F.G.H --> E1.F1.G1.H1 netmask 0xffffffff
> Opened by PID 1387
>
> tun0 is created by ppp(8)
>
> in /etc/ppp.conf is:
> default:
> set log Phase Chat LCP IPCP CCP tun command
> set server /var/run/ppp/internet "" 0177
> set device PPPoE:rl0
> set speed sync
> enable lqr echo
> set lqrperiod 30
> set login
> set ctsrts off
> add default HISADDR
> set timeout 0
> set redial 0 0
> set cd 5
>
> tun1 is created by OpenVPN with configuration:
> client
> dev tun1
> proto udp
> ...
>
> so, what can cause the collisions and can i fix them?
>
It seems tun(4) just increments collision counter whenever it
can't enqueue packet. Because it's not collision at all I think
it's a bug that had been there from day 1. Just nuking updating the
counter will address the issue. You still can get the previous
collision counter of tun(4) with d option of netstat which shows
number of packets dropped due to send queue full.
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Index: sys/net/if_tun.c
===================================================================
--- sys/net/if_tun.c (revision 221175)
+++ sys/net/if_tun.c (working copy)
@@ -661,10 +661,8 @@
}
error = (ifp->if_transmit)(ifp, m0);
- if (error) {
- ifp->if_collisions++;
+ if (error)
return (ENOBUFS);
- }
ifp->if_opackets++;
return (0);
}
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