Re: [PATCH bpf-next] net: netfilter: Make ct zone id configurable for bpf ct helper functions

[Martin KaFai Lau <martin.lau@linux.dev>]

On 3/28/24 9:14 PM, Brad Cowie wrote:
> Add ct zone id to bpf_ct_opts so that arbitrary ct zone can be
> set for xdp/tc bpf ct helper functions bpf_{xdp,skb}_ct_alloc
> and bpf_{xdp,skb}_ct_lookup.
> 
> Signed-off-by: Brad Cowie <brad@faucet.nz>
> ---
>   net/netfilter/nf_conntrack_bpf.c              | 23 ++++++++++---------
>   .../testing/selftests/bpf/prog_tests/bpf_nf.c |  1 -
>   .../testing/selftests/bpf/progs/test_bpf_nf.c | 13 ++---------
>   3 files changed, 14 insertions(+), 23 deletions(-)
> 
> diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
> index d2492d050fe6..a0f8a64751ec 100644
> --- a/net/netfilter/nf_conntrack_bpf.c
> +++ b/net/netfilter/nf_conntrack_bpf.c
> @@ -30,7 +30,6 @@
>    * @error      - Out parameter, set for any errors encountered
>    *		 Values:
>    *		   -EINVAL - Passed NULL for bpf_tuple pointer
> - *		   -EINVAL - opts->reserved is not 0
>    *		   -EINVAL - netns_id is less than -1
>    *		   -EINVAL - opts__sz isn't NF_BPF_CT_OPTS_SZ (12)
>    *		   -EPROTO - l4proto isn't one of IPPROTO_TCP or IPPROTO_UDP
> @@ -42,16 +41,14 @@
>    *		 Values:
>    *		   IPPROTO_TCP, IPPROTO_UDP
>    * @dir:       - connection tracking tuple direction.
> - * @reserved   - Reserved member, will be reused for more options in future
> - *		 Values:
> - *		   0
> + * @ct_zone    - connection tracking zone id.
>    */
>   struct bpf_ct_opts {
>   	s32 netns_id;
>   	s32 error;
>   	u8 l4proto;
>   	u8 dir;
> -	u8 reserved[2];
> +	u16 ct_zone;

How about the other fields (flags and dir) in the "struct nf_conntrack_zone" and 
would it be useful to have values other than the default?

[ ... ]

> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> index b30ff6b3b81a..25c3c4e87ed5 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> @@ -103,7 +103,6 @@ static void test_bpf_nf_ct(int mode)
>   		goto end;
>   
>   	ASSERT_EQ(skel->bss->test_einval_bpf_tuple, -EINVAL, "Test EINVAL for NULL bpf_tuple");
> -	ASSERT_EQ(skel->bss->test_einval_reserved, -EINVAL, "Test EINVAL for reserved not set to 0");
>   	ASSERT_EQ(skel->bss->test_einval_netns_id, -EINVAL, "Test EINVAL for netns_id < -1");
>   	ASSERT_EQ(skel->bss->test_einval_len_opts, -EINVAL, "Test EINVAL for len__opts != NF_BPF_CT_OPTS_SZ");
>   	ASSERT_EQ(skel->bss->test_eproto_l4proto, -EPROTO, "Test EPROTO for l4proto != TCP or UDP");
> diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> index 77ad8adf68da..4adb73bc1b33 100644
> --- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> +++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> @@ -45,7 +45,8 @@ struct bpf_ct_opts___local {
>   	s32 netns_id;
>   	s32 error;
>   	u8 l4proto;
> -	u8 reserved[3];
> +	u8 dir;
> +	u16 ct_zone;
>   } __attribute__((preserve_access_index));
>   
>   struct nf_conn *bpf_xdp_ct_alloc(struct xdp_md *, struct bpf_sock_tuple *, u32,
> @@ -84,16 +85,6 @@ nf_ct_test(struct nf_conn *(*lookup_fn)(void *, struct bpf_sock_tuple *, u32,
>   	else
>   		test_einval_bpf_tuple = opts_def.error;
>   
> -	opts_def.reserved[0] = 1;
> -	ct = lookup_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> -		       sizeof(opts_def));
> -	opts_def.reserved[0] = 0;
> -	opts_def.l4proto = IPPROTO_TCP;
> -	if (ct)
> -		bpf_ct_release(ct);
> -	else
> -		test_einval_reserved = opts_def.error;
> -

Can it actually test an alloc and lookup of a non default zone id?

Please also separate the selftest into another patch.

pw-bot: cr

>   	opts_def.netns_id = -2;
>   	ct = lookup_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
>   		       sizeof(opts_def));