NFD

When we initially implemented this part, we didn't have FaceQuery command that is required to check existence of the supplied face id. Now we have it, and I think we should add the sanity check and avoid confusion.

NFD Management protocol - RibMgmt specifies:

If face does not exist, the command fails with code 410.

This is a problem in RibManager rather than nfdc.
Attached tcpdump trace (obtained by setting transport=tcp4://127.0.0.1:6363 in client.conf then capture on lo interface) shows the response for rib/register command was 200.

I'm assigning this to Vince who implemented this command handler.

#2857 is in progress and will conflict with this fix.
The two assignees should coordinate with each other and decide in which order should the two issues be worked on.

NFD Management protocol - RibMgmt specifies:

If face does not exist, the command fails with code 410.

I realize that letting NFD-RIB fail a registration for non-existent face is not implementable: it may cause prefix registration errors on newly created faces. Consider this scenario:

1. NFD receives a prefix registration command at the very first Interest that caused the creation of an on-demand face.
2. A face event notification is generated when the on-demand face is created. NFD-RIB subscribes to this notification stream.
3. The prefix registration command is sent to NFD-RIB.

Recall that forwarding does not guarantee in-order delivery. Thus, NFD-RIB may receive the face creation notification and the prefix registration command in any order. In case the registration arrives before the notification, NFD-RIB would perceive the face as non-existent.

Thus, I think the solution is:

• In RibMgmt, rib/register should succeed even if face does not exist. A successful response simply means the registration request is accepted.
• nfdc route add command should check the existence of face (when FaceId is specified) before invoking rib/register command.

As explained in note-4, letting NFD-RIB fail a registration for non-existent face is not implementable.
410 error is deleted in RibMgmt r22.

nfdc register command is deprecated in favour of nfdc route add. nfdc route add behaves as specified in note-4:

vagrant@m0212:~/NFD$ nfdc route add /org/openmhealth 400
Face not found
vagrant@m0212:~/NFD$ echo $?
3