Unfortunately some distros don't have their kernel version defined
accurately in <linux/version.h> due to different long term support
reasons.
It is important to have a way to override the bpf kern_version
attribute during runtime: some old kernels might still check for
kern_version attribute during bpf_prog_load().
Signed-off-by: Rafael David Tinoco <rafaeldtinoco@xxxxxxxxxx>
---
tools/lib/bpf/libbpf.c | 10 ++++++++++
tools/lib/bpf/libbpf.h | 1 +
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 12 insertions(+)
Hi Andrii and Rafael,
Did you consider making kernel version an attribute of the load
API, bpf_prog_load_xattr()? This feels slightly more natural
to me, to tell the API the kernel you need at load time.
Hi John,
This is how I'm using:
https://github.com/rafaeldtinoco/portablebpf/blob/master/mine.c#L285
Although, I don't use the skeleton pieces so maybe it would be
awkward for that usage.
having a xxx_bpf object:
xxx_bpf__open_and_load() -> xxx_bpf__load() ->
bpf_object__load_skeleton() -> bpf_object_load() -> bpf_object__loadxattr()
We would have to add kern_version to 'bpf_object_skeleton' struct, to be
passed to 'bpf_object__load_skeleton()' to have it passed on.
I'll let Andrii to see what he prefers.
Note:
Reason for all this (including the legacy kprobe logic, in other commit)
is to continue the
https://github.com/rafaeldtinoco/conntracker/tree/poc-cmd project,
making sure it supports 4.x kernels. Still adding bpf support to it
(identify task/pid per flow) and will replace the libnf* usage with bpf
after that.
Thanks
-rafaeldtinoco
