lwAFTR doesn't respond to pings at internal-interface

[dpino]

The script that tests pings to internal and external interfaces is no longer working.

sudo SNABB_PCI0=0000:82:00.0 SNABB_PCI1=0000:02:00.0 program/lwaftr/tests/hw/test_ping_on_a_stick.sh
Error: Couldn't ping to internal interface

I debugged the error and the last known good commit is 3d9ad9ac013f253579f3f0bb05067dd2e0eb015b. One commit after, ae714b66285c2f2becfe48f38bdb49620747cb14, the script fails.

NOTES:

• At this moment there's an error in the script. Command ping6 should be ping -6.
• This test is not a selftest because the test doesn't work when run inside a Docket container.

[dpino]

NA response in ae714b6 is wrong due to bad formatting of the frame (checksum is not correct). When comparing NA from 3d9ad9a with NA from lwaftr, there are no differences.

[dpino]

I learned that if running lwaftr with two physical interfaces, ping to the internal interface works.

$ sudo ./snabb lwaftr run --conf program/lwaftr/tests/data/lwaftr-vlan.conf \
   --v4 82:00.0 --v6 82:00.1

$ sudo SNABB_PCI0=0000:82:00.0 SNABB_PCI1=0000:02:00.1 \ 
   program/lwaftr/tests/hw/test_ping_on_a_stick.sh