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

PATEL Harsh harsh.patel at sagemcom.com
Thu Oct 17 21:32:57 UTC 2019


Just to let you know Gregory. I have not configured any iptables or 
ip6tables rule. And i am accepting all input and output traffic.


Thanks,
Harsh

On 10/17/2019 11:30 PM, Gregory Rose wrote:
> Real sender is: gvrose8192 at gmail.com
>
> ----------------------------------------------------------------------
>
> On 10/16/2019 3:18 PM, Ben Pfaff wrote:
>> 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.
>
> I have seen a lot of kernel bugs (maybe we should call them unintended 
> side effects) in ICMPV6 handling.  It's just
> a suggestion to see if it makes a difference.  Depending on how other 
> rules on the system are set up the ICMPv6
> packets might get dropped in the kernel.
>
> I noted that you are not having the same issue when you try branch 
> 2.8.2 so I'm wondering if there's
> a kernel issue or perhaps other system rules (IP tables?) that are 
> interfering.
>
> Thanks,
>
> - Greg
>
>>
>>>> ------------------------------------------------------------------------ 
>>>>
>>>> *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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