Re: [PATCH net-next v2] net: Add support for filtering neigh dump by master device

[David Ahern <dsa@cumulusnetworks.com>]

On 10/2/15 11:18 AM, Eric W. Biederman wrote:
> What is the thinking here because it sure looks like you are busily
> adding layer two functionality you swore you did not want.

Interfaces are enslaved to a VRF device, but neighbor entries are 
installed with a reference to the actual interface not the VRF device.

This patch (plus the iproute2 one) fills a gap for usability and 
debugging. I have one more patch to go and then I will send an update to 
the documentation, but here is a preview (documentation update has more 
detail via examples):

Using iproute2 for VRFs
1. Create a VRF
    ip link add dev NAME type vrf table ID

2. List VRFs
    ip [-d] link show type vrf
    --> -d is needed to show table id

3. Assign a Network Interface to a VRF
    ip link set dev NAME master VRF-NAME

4. Show Devices Assigned to a VRF
    ip [-br] link show master VRF-NAME

5. Show Neighbor Entries for a VRF
    ip [-6] neigh show master VRF-NAME

    (This patch is what makes this command work efficiently.)

6. Show Addresses Assigned to Interfaces in a VRF
    ip [-br][-6] addr show master VRF-NAME

7. Show Routes for a VRF
    ip [-6] route show table ID

8. Route Lookup for a VRF
    ip [-6] route get oif VRF-NAME ADDRESS

    (This one needs a kernel patch to display the correct entry.)

David