[ovs-discuss] Ignore packets of a certain mac type

[Ben Pfaff]

On Tue, Oct 08, 2013 at 10:44:34AM -0700, Nithin Nayak Sujir wrote:
> 
> On 10/07/2013 06:39 PM, Ben Pfaff wrote:
> 
> >>Final flow: unchanged
> >>Relevant fields: skb_priority=0,in_port=ANY,dl_type=0x8914,nw_frag=no
> >>Datapath actions: 1
> >
> >This looks correct.  The next step is to use "ovs-dpctl dump-flows" to
> >see what's happening to the actual packets when the kernel handles them.
> >
> 
> 
> Thanks for the pointer, Ben.
> 
> Here is the output of dump-flows
> # ovs-dpctl dump-flows
> skb_priority(0),in_port(2),eth_type(0x8100),encap(eth_type(0x8914)),
> packets:38, bytes:2776, used:0.794s, actions:1
[...]
> 
> 
> It's showing the eth_type as 0x8100 and encap(eth_type(0x8914)). Is
> this a bug in parsing the packet? Here is the packet detail from
> wireshark. There is no vlan 0x8100 header as you can see.

I don't understand how there could be a bug of that magnitude.
Wireshark calls this packet a "FIP VLAN Response".  Knowing nothing
about FIP, a packet with that name sounds to me quite likely to be
inside a VLAN.

Either way, this flow dump shows that the packet is being sent out
port 1.  The next step is to use "ovs-dpctl show" to find out what
port 1 is, and then tcpdump or otherwise watch what is going out port
1.