Fix name generation for BPF metrics

[marctc]

• Fixed how names are fetched, making possible to get the full name!
• Bump cillium to 0.17
• Simplified logic of metrics collection
• Fetch only probes that are Kprobes (this includes all Beyla probes)
• Fetch only maps that are LRUHash (this includes all Beyla maps)

[codecov]

Codecov Report

Attention: Patch coverage is 3.89610% with 74 lines in your changes missing coverage. Please review.

Project coverage is 34.66%. Comparing base (b535e56) to head (90c0387).

Files with missing lines	Patch %	Lines
pkg/export/prom/prom_bpf.go	0.00%	56 Missing ⚠️
pkg/internal/netolly/ebpf/sock_tracer.go	0.00%	8 Missing ⚠️
pkg/internal/netolly/ebpf/tracer.go	0.00%	7 Missing ⚠️
pkg/internal/ebpf/tracer_linux.go	50.00%	2 Missing and 1 partial ⚠️

❗ There is a different number of reports uploaded between BASE (b535e56) and HEAD (90c0387). Click for more details.

HEAD has 4 uploads less than BASE

Flag	BASE (b535e56)	HEAD (90c0387)
oats-test	2	1
integration-test	2	0
unittests	1	0

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1552       +/-   ##
===========================================
- Coverage   67.74%   34.66%   -33.08%     
===========================================
  Files         197      193        -4     
  Lines       19755    19598      -157     
===========================================
- Hits        13383     6794     -6589     
- Misses       5685    12214     +6529     
+ Partials      687      590       -97     

Flag	Coverage Δ
integration-test	?
oats-test	34.66% <3.89%> (+0.01%)	⬆️
unittests	?

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[rafaelroquetto]

LGTM! The way you encapsulated the name fetching is really elegant. I've added a few suggestions, which are mere ... suggestions (and very personal taste, so feel free to ignore).

[rafaelroquetto]

Looking closer at the ebpf code, it turns out this may require CAP_SYS_ADMIN, which could be problematic:

// FuncInfos returns the offset and function information of all (sub)programs in
// a BPF program.
//
// Available from 5.0.
//
// Requires CAP_SYS_ADMIN or equivalent for reading BTF information. Returns
// ErrNotSupported if the program was created without BTF or if the kernel
// doesn't support the field.
func (pi *ProgramInfo) FuncInfos() (btf.FuncOffsets, error) { ... }

I don't see a simple way out (without BTF and without renaming the probes) apart from generating a go map matching the 16 first chars as a key and the full probe name as a value. I hacked a quick script that does it just a a POC, so we could maybe do something similar in go and invoke with //go:generate inside prom_bpf.go.

Here's the script (place it inside the ebpf dir if you want to run it)
gen_probe_map.pl.gz

And the proposed (generated) output:
probe_map.go.txt