NFD » ndn-cxx

This property should be applied per InterestFilter, not per face. ChronoSync, among others, depends on being able to send Interests to the network even if they match a local InterestFilter. At the same time, an application using ChronoSync may simultaneously export per-instance certificates to be collected by BundleBuilder.

I suggest the name "Interest loopback". This name is analogous to IP_MULTICAST_LOOP socket option.

I recommend this API:

face.setInterestFilter(
  InterestFilter("/my-app").allowLoopback(false),
  [] (const InterestFilter&, const Interest&) {});

Interest interest("/A");
interest.setTag(make_shared<InterestLoopbackTag>(true));
face.expressInterest(interest, nullptr, nullptr, nullptr);

The default on InterestFilter is allowing Interest loopback, while the default on expressInterest is disallowing Interest loopback. Having at least one default as "disallowed" avoids changing behavior of existing applications.

20170807 NFD call approves the name "Interest loopback".

It's decided that a client face shall behave like NFD's multicast strategy.
InterestFilter("/my-app").allowLoopback(false) API is needed, so that ChronoSync and the likes could disable this feature.
There's no need to have an option on expressInterest side.

When Interest loopback is enabled, even if the Interest is dispatched to one or more InterestCallbacks, it should still be sent to NFD simultaneously. In BundleBuilder's use case, in case the application itself doesn't have the certificate, the certificate may still be available elsewhere through NFD.

https://gerrit.named-data.net/4233

https://gerrit.named-data.net/4356 ChronoSync

It's sufficient to disallow Interest loopback on "sync prefix" (in logic.cpp) only.
A party does not send Interest to its own "user prefix" (in socket.cpp), so that Interest loopback can remain at the default "allowed" setting.