selftests/bpf: fix missing BPF object files

After commit afef88e65554 ("selftests/bpf: Store BPF object files with
.bpf.o extension"), we should use *.bpf.o instead of *.o.

In addition, use the BPF_FILE variable to save the BPF object file name,
which can be better identified and modified.

Fixes: afef88e65554 ("selftests/bpf: Store BPF object files with .bpf.o extension")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/1666235134-562-1-git-send-email-wangyufen@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf/test_xdp_meta: use temp netns for testing

Use temp netns instead of hard code name for testing in case the
netns already exists.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Link: https://lore.kernel.org/r/20220125081717.1260849-7-liuhangbin@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Use kselftest skip code for skipped tests

There are several test cases in the bpf directory are still using
exit 0 when they need to be skipped. Use kselftest framework skip
code instead so it can help us to distinguish the return status.

Criterion to filter out what should be fixed in bpf directory:
grep -r "exit 0" -B1 | grep -i skip

This change might cause some false-positives if people are running
these test scripts directly and only checking their return codes,
which will change from 0 to 4. However I think the impact should be
small as most of our scripts here are already using this skip code.
And there will be no such issue if running them with the kselftest
framework.

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210929051250.13831-1-po-hsu.lin@canonical.com

tools/bpf: fix batch-mode test failure of test_xdp_redirect.sh

The tests at tools/testing/selftests/bpf can run in patch mode, e.g.,
make -C tools/testing/selftests/bpf run_tests

With the batch mode, I experimented intermittent test failure of
test_xdp_redirect.sh.
....
selftests: test_xdp_redirect [PASS]
selftests: test_xdp_redirect.sh [PASS]
RTNETLINK answers: File exists
selftests: test_xdp_meta [FAILED]
selftests: test_xdp_meta.sh [FAIL]
....

The following illustrates what caused the failure:
(1). test_xdp_redirect creates veth pairs (veth1,veth11) and
(veth2,veth22), and assign veth11 and veth22 to namespace
ns1 and ns2 respectively.
(2). at the end of test_xdp_redirect test, ns1 and ns2 are
deleted. During this process, the deletion of actual
namespace resources, including deletion of veth1{1} and veth2{2},
is put into a workqueue to be processed asynchronously.
(3). test_xdp_meta tries to create veth pair (veth1, veth2).
The previous veth deletions in step (2) have not finished yet,
and veth1 or veth2 may be still valid in the kernel, thus
causing the failure.

The fix is to explicitly delete the veth pair before test_xdp_redirect
exits. Only one end of veth needs deletion as the kernel will delete
the other end automatically. Also test_xdp_meta is also fixed in
similar manner to avoid future potential issues.

Fixes: 996139e801fd ("selftests: bpf: add a test for XDP redirect")
Fixes: 22c8852624fc ("bpf: improve selftests and add tests for meta pointer")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

bpf: improve selftests and add tests for meta pointer

Add various test_verifier selftests, and a simple xdp/tc functional
test that is being attached to veths. Also let new versions of clang
use the recently added -mcpu=probe support [1] for the BPF target,
so that it can probe the underlying kernel for BPF insn set extensions.
We could also just set this options always, where older versions just
ignore it and give a note to the user that the -mcpu value is not
supported, but given emitting the note cannot be turned off from clang
side lets not confuse users running selftests with it, thus fallback
to the default generic one when we see that clang doesn't support it.
Also allow CPU option to be overridden in the Makefile from command
line.

[1] https://github.com/llvm-mirror/llvm/commit/d7276a40d87b89aed89978dec6457a5b8b3a0db5

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>