Subject: Re: [PATCH bpf-next v4 2/3] selftests/bpf: Add connmark read test

From: Martin KaFai Lau <[email-masked]>
Date: Tue, 11 Oct 2022 22:49:32 -0700

On 8/11/22 2:55 PM, Daniel Xu wrote:
> Test that the prog can read from the connection mark. This test is nice
> because it ensures progs can interact with netfilter subsystem
> correctly.
> 
> Signed-off-by: Daniel Xu <[email-masked]>
> Acked-by: Kumar Kartikeya Dwivedi <[email-masked]>
> ---
>   tools/testing/selftests/bpf/prog_tests/bpf_nf.c | 3 ++-
>   tools/testing/selftests/bpf/progs/test_bpf_nf.c | 3 +++
>   2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> index 88a2c0bdefec..544bf90ac2a7 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> @@ -44,7 +44,7 @@ static int connect_to_server(int srv_fd)
>   
>   static void test_bpf_nf_ct(int mode)
>   {
> -	const char *iptables = "iptables -t raw %s PREROUTING -j CT";
> +	const char *iptables = "iptables -t raw %s PREROUTING -j CONNMARK --set-mark 42/0";
Hi Daniel Xu, this test starts failing recently in CI [0]:

Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id: Invalid 
argument

   Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id: Invalid 
argument

   Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id: Invalid 
argument

   Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id: Invalid 
argument

   test_bpf_nf_ct:PASS:test_bpf_nf__open_and_load 0 nsec
   test_bpf_nf_ct:FAIL:iptables unexpected error: 1024 (errno 0)

Could you help to take a look? Thanks.

[0]: https://github.com/kernel-patches/bpf/actions/runs/3231598391/jobs/5291529292

>   	int srv_fd = -1, client_fd = -1, srv_client_fd = -1;
>   	struct sockaddr_in peer_addr = {};
>   	struct test_bpf_nf *skel;
> @@ -114,6 +114,7 @@ static void test_bpf_nf_ct(int mode)
>   	/* expected status is IPS_SEEN_REPLY */
>   	ASSERT_EQ(skel->bss->test_status, 2, "Test for ct status update ");
>   	ASSERT_EQ(skel->data->test_exist_lookup, 0, "Test existing connection lookup");
> +	ASSERT_EQ(skel->bss->test_exist_lookup_mark, 43, "Test existing connection lookup ctmark");
>   end:
>   	if (srv_client_fd != -1)
>   		close(srv_client_fd);
> diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> index 84e0fd479794..2722441850cc 100644
> --- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> +++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> @@ -28,6 +28,7 @@ __be16 sport = 0;
>   __be32 daddr = 0;
>   __be16 dport = 0;
>   int test_exist_lookup = -ENOENT;
> +u32 test_exist_lookup_mark = 0;
>   
>   struct nf_conn;
>   
> @@ -174,6 +175,8 @@ nf_ct_test(struct nf_conn *(*lookup_fn)(void *, struct bpf_sock_tuple *, u32,
>   		       sizeof(opts_def));
>   	if (ct) {
>   		test_exist_lookup = 0;
> +		if (ct->mark == 42)
> +			test_exist_lookup_mark = 43;
>   		bpf_ct_release(ct);
>   	} else {
>   		test_exist_lookup = opts_def.error;