[ovs-discuss] OVS drops icmpv6 packets for actions:NORMAL

Ben Pfaff blp at ovn.org
Wed Oct 16 22:18:32 UTC 2019


On Tue, Oct 15, 2019 at 04:11:16PM -0700, Gregory Rose wrote:
> 
> On 10/15/2019 3:18 PM, PATEL Harsh wrote:
> > Hey Ben,
> > Thanks for your response. I am using Linux 4.1.52 os. And can you please
> > tell me what happens when this Normal flows drops packet I mean which
> > part is responsible for this failure. Because for some traffics like
> > ipv4 unicast and ipv6 unicast this flow works. Just for icmpv6 it drops
> > the packet.
> > 
> 
> Could be your kernel - I'd try a newer one.

Do you have a reason to believe that?  How OVS translates flows isn't
too kernel version dependent.

> > ------------------------------------------------------------------------
> > *From:* Ben Pfaff <blp at ovn.org>
> > *Sent:* Tuesday, October 15, 2019 1:30 PM
> > *To:* PATEL Harsh <harsh.patel at sagemcom.com>
> > *Cc:* ovs-discuss at openvswitch.org <ovs-discuss at openvswitch.org>
> > *Subject:* Re: [ovs-discuss] OVS drops icmpv6 packets for actions:NORMAL
> > On Tue, Oct 15, 2019 at 07:22:11PM +0000, PATEL Harsh wrote:
> > > Hi,
> > > I have been using openvswitch version 2.8.2. And I haven't added any
> > > flows to forward traffic. Just the default one that is as followed.
> > With
> > > this flow seems like my bridge BR_LAN drops incoming icmpv6 traffice
> > > from LAN client. There is also detailed flow as follows in that it says
> > > datapath actions: drop. I don't know why this is happening can you
> > > please help me with that?
> > >
> > >   ovs-ofctl dump-flows BR_LAN
> > >   cookie=0x0, duration=7210.426s, table=0, n_packets=117886,
> > > n_bytes=85217235, priority=0 actions=NORMAL
> > >
> > >
> > > Detailed flow for LAN client:
> > >
> > > ovs-appctl ofproto/trace BR_LAN dl_src=00:00:00:04:eb:d0,dl_dst=
> > > 33:33:00:00:00:fb,dl_type=0x86dd
> > > Flow:
> > > ipv6,in_port=ANY,vlan_tci=0x0000,dl_src=00:00:00:04:eb:d0,dl_dst=33:33:00:00:00:fb,ipv6_src=::,ipv6_dst=::,ipv6_label=0x00000,nw_proto=0,nw_tos=0,nw_ecn=0,nw_ttl=0
> > >
> > > bridge("BR_LAN")
> > > ----------------
> > >   0. priority 0
> > >      NORMAL
> > >
> > > Final flow: unchanged
> > > Megaflow:
> > > recirc_id=0,eth,ipv6,in_port=ANY,vlan_tci=0x0000/0x1fff,dl_src=00:00:00:04:eb:d0,dl_dst=33:33:00:00:00:fb,ipv6_dst=::,nw_proto=0,nw_frag=no
> > > Datapath actions: drop
> > 
> > With recent OVS, I'm not seeing this problem:
> > 
> >     [bpfaff at sigfpe tutorial]$ ovs-vsctl add-br BR_LAN
> >     [bpfaff at sigfpe tutorial]$ ovs-vsctl add-port BR_LAN p0
> >     [bpfaff at sigfpe tutorial]$ ovs-vsctl add-port BR_LAN p1
> >     [bpfaff at sigfpe tutorial]$ ovs-vsctl add-port BR_LAN p2
> >     [bpfaff at sigfpe tutorial]$ ovs-appctl ofproto/trace BR_LAN
> > dl_src=00:00:00:04:eb:d0,dl_dst=33:33:00:00:00:fb,dl_type=0x86dd
> >     Flow: ipv6,in_port=ANY,vlan_tci=0x0000,dl_src=00:00:00:04:eb:d0,dl_dst=33:33:00:00:00:fb,ipv6_src=::,ipv6_dst=::,ipv6_label=0x00000,nw_proto=0,nw_tos=0,nw_ecn=0,nw_ttl=0
> > 
> >     bridge("BR_LAN")
> >     ----------------
> >      0. priority 0
> >         NORMAL
> >          -> no learned MAC for destination, flooding
> > 
> >     Final flow: unchanged
> >     Megaflow: recirc_id=0,eth,ipv6,in_port=ANY,dl_src=00:00:00:04:eb:d0,dl_dst=33:33:00:00:00:fb,nw_frag=no
> >     Datapath actions: 1,2,3,4
> >     [bpfaff at sigfpe tutorial]$
> > 
> > I also don't see the problem when I go back to the latest 2.8.x.
> > 
> > I wonder what's different about your setup.
> > ------------------------------------------------------------------------
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