Map of maps

[geyslan]

Close: #93
Context: #343 #213

commit faa3599 (HEAD -> map-of-maps, origin/map-of-maps)
Author: Geyslan Gregório geyslan@gmail.com
Date: Wed Aug 16 09:27:09 2023 -0300

feat(btf): introduce GetBTFFDByID()

This allows to get a FD to a BTF by its ID. This is useful to create a
BPFMapLow passing options set with a BTF ID.

commit cbd23d8
Author: Geyslan Gregório geyslan@gmail.com
Date: Mon Aug 14 09:17:20 2023 -0300

chore(selftest): map-of-maps-outer-low-inner-low

Introduce a new selftest that tests a map of maps with outer and inner
maps not pre-allocated in the BPF program.

commit 8634026
Author: Geyslan Gregório geyslan@gmail.com
Date: Mon Aug 14 09:00:56 2023 -0300

chore(selftest): map-of-maps-outer-high-inner-low

Introduce a new selftest that tests a map of maps with outer map
pre-allocated in the BPF program and an inner map from other origin -
not pre-allocated in the BPF program.

commit 00f47dd
Author: Geyslan Gregório geyslan@gmail.com
Date: Mon Aug 14 08:29:21 2023 -0300

chore(selftest): map-of-maps-outer-high-inner-high

Introduce a new selftest that tests a map of maps with outer and inner
maps pre-allocated in the BPF program.

commit bc7cb55
Author: Geyslan Gregório geyslan@gmail.com
Date: Fri Aug 11 18:30:23 2023 -0300

feat(map): introduce InnerMapInfo()

This allows to query the inner map information from the outer map before
the module is loaded.

Despite acting as a wrapper around bpf_map__inner_map(), which returns a
pointer to a libbpf bpf_map, it is not safe to use it as a BPFMap since
it will never be created. As soon as the module is loaded, the bpf_map
is destroyed. This is the reason why it returns a BPFMapInfo instead.

commit c834f37
Author: Geyslan Gregório geyslan@gmail.com
Date: Fri Aug 11 16:32:48 2023 -0300

feat(map): introduce SetInnerMapFD()

This allows to set the inner map prototype of a map of maps which
doesn't have a pre-allocated inner map.

Initial effort: #213

Co-authored-by: Kemal Akkoyun <kakkoyun@gmail.com>

commit b28c448
Author: Geyslan Gregório geyslan@gmail.com
Date: Thu Aug 10 18:53:04 2023 -0300

feat(map): introduce GetMapByID()

This function allows to retrieve a map (BPFMapLow) by its ID. This is
useful when a map is created by a different origin.

Initial effort: #213

Co-authored-by: Kemal Akkoyun <kakkoyun@gmail.com>

commit 26259e3
Author: Geyslan Gregório geyslan@gmail.com
Date: Thu Aug 10 14:41:57 2023 -0300

feat(map): introduce GetMapFDByID()

This function allows to get a file descriptor of a map by its ID.

[yanivagman]

LGTM