Split logic

[geyslan]

Close: #355
Close: #365
Close: #159
Close: #357

commit f1738f9 (HEAD -> split-logic, origin/split-logic)

chore: consider errno in NULL return

commit 62f0ccc

chore(prog): add TODO

commit 0228f12

chore: give breath to the code putting spaces

This adds spaces to the code to make it more readable.

This also puts RingBuffer.Stop() and PerfBuffer.Stop() happy path
out of the branching logic.

commit 77c521f

chore(prog): remove inner name field

The API must rely on the program name returned by the libbpf API.

commit 87088b6

chore: standardize defer use

Applied the use of 'defer' for better resource management.

commit 3aeb45b

fix(link)!: Unpin link API

The underlying bpf_link__unpin() does not receive a pointer to the
pin path, only for the link itself.

commit 1b882cf

chore: add information to SetStrictMode()

SetStrictMode is no-op as of libbpf v1.0.

commit 913d1ea

chore: use cgo_* helpers for struct lifecycle

Introduced struct helpers to manage the C struct lifecycle on the C side,
which avoids problems with structs which may contain bitfields. See #244.

  - cgo_bpf_map_info_new()
  - cgo_bpf_map_info_size()
  - cgo_bpf_map_info_free()

  - cgo_bpf_tc_opts_new()
  - cgo_bpf_tc_opts_free()

  - cgo_bpf_tc_hook_new()
  - cgo_bpf_tc_hook_free()

Based on the same #244 concerns, introduced bpf_map_info getters:

  - cgo_bpf_map_info_type()
  - cgo_bpf_map_info_id()
  - cgo_bpf_map_info_key_size()
  - cgo_bpf_map_info_value_size()
  - cgo_bpf_map_info_max_entries()
  - cgo_bpf_map_info_map_flags()
  - cgo_bpf_map_info_name()
  - cgo_bpf_map_info_ifindex()
  - cgo_bpf_map_info_btf_vmlinux_value_type_id()
  - cgo_bpf_map_info_netns_dev()
  - cgo_bpf_map_info_netns_ino()
  - cgo_bpf_map_info_btf_id()
  - cgo_bpf_map_info_btf_key_type_id()
  - cgo_bpf_map_info_btf_value_type_id()
  - cgo_bpf_map_info_map_extra()

  - cgo_bpf_tc_opts_prog_fd()
  - cgo_bpf_tc_opts_flags()
  - cgo_bpf_tc_opts_prog_id()
  - cgo_bpf_tc_opts_handle()
  - cgo_bpf_tc_opts_priority()

Changed these functions to use cgo_* struct handlers:

  - NewModuleFromFileArgs()
  - GetMapInfoByFD()
  - TcHook.Destroy()
  - TcHook.Attach()
  - TcHook.Detach()
  - TcHook.Query()

commit a4c5f50

chore(go): rename C variables

- Changed C function returns to 'retC' in functions that return error
  values to avoid confusion with possible use of errno.
- Changed returns to 'valueC' in functions that return 'value' or
  pointers to 'value'.

This also changed comparisons to "< 0" instead of "!= 0".

commit 0c6a05f

chore(link): make BPF link legacy a private type

It has no methods, and is only used embedded in the BPFLink type.

commit c192943

chore: split logic into multiple files

This only moves code around, no functional changes.