Re: [PATCH v3 bpf-next 5/5] selftests/bpf: add selftest for bpf_xdp_ct_add and bpf_ct_refresh_timeout kfunc

[Yonghong Song <yhs@xxxxxx>]

On 5/18/22 3:43 AM, Lorenzo Bianconi wrote:
> Introduce selftests for the following kfunc helpers:
> - bpf_xdp_ct_add
> - bpf_skb_ct_add
> - bpf_ct_refresh_timeout
>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> ---
>   .../testing/selftests/bpf/prog_tests/bpf_nf.c |  4 ++
>   .../testing/selftests/bpf/progs/test_bpf_nf.c | 72 +++++++++++++++----
>   2 files changed, 64 insertions(+), 12 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> index dd30b1e3a67c..be6c5650892f 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> @@ -39,6 +39,10 @@ void test_bpf_nf_ct(int mode)
>   	ASSERT_EQ(skel->bss->test_enonet_netns_id, -ENONET, "Test ENONET for bad but valid netns_id");
>   	ASSERT_EQ(skel->bss->test_enoent_lookup, -ENOENT, "Test ENOENT for failed lookup");
>   	ASSERT_EQ(skel->bss->test_eafnosupport, -EAFNOSUPPORT, "Test EAFNOSUPPORT for invalid len__tuple");
> +	ASSERT_EQ(skel->bss->test_add_entry, 0, "Test for adding new entry");
> +	ASSERT_EQ(skel->bss->test_succ_lookup, 0, "Test for successful lookup");

The default value for test_add_entry/test_succ_lookup are 0. So even if 
the program didn't execute, the above still succeeds. So testing with
a non-default value (0) might be a better choice.

> +	ASSERT_TRUE(skel->bss->test_delta_timeout > 9 && skel->bss->test_delta_timeout <= 10,
> +		    "Test for ct timeout update");

ASSERT_TRUE(skel->bss->test_delta_timeout == 10, ...)? Could you add 
some comments on why the value should be 10. It is not obvious by
inspecting the code.

>   end:
>   	test_bpf_nf__destroy(skel);
>   }
> diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> index f00a9731930e..361430dde3f7 100644
> --- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> +++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> @@ -1,6 +1,7 @@
>   // SPDX-License-Identifier: GPL-2.0
>   #include <vmlinux.h>
>   #include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_endian.h>
>   
>   #define EAFNOSUPPORT 97
>   #define EPROTO 71
> @@ -8,6 +9,8 @@
>   #define EINVAL 22
>   #define ENOENT 2
>   
> +extern unsigned long CONFIG_HZ __kconfig;
> +
>   int test_einval_bpf_tuple = 0;
>   int test_einval_reserved = 0;
>   int test_einval_netns_id = 0;
> @@ -16,6 +19,9 @@ int test_eproto_l4proto = 0;
>   int test_enonet_netns_id = 0;
>   int test_enoent_lookup = 0;
>   int test_eafnosupport = 0;
> +int test_add_entry = 0;
> +int test_succ_lookup = 0;
> +u32 test_delta_timeout = 0;
>   
>   struct nf_conn;
>   
> @@ -26,31 +32,40 @@ struct bpf_ct_opts___local {
>   	u8 reserved[3];
>   } __attribute__((preserve_access_index));
>   
> +struct nf_conn *bpf_xdp_ct_add(struct xdp_md *, struct bpf_sock_tuple *, u32,
> +			       struct bpf_ct_opts___local *, u32) __ksym;
>   struct nf_conn *bpf_xdp_ct_lookup(struct xdp_md *, struct bpf_sock_tuple *, u32,
>   				  struct bpf_ct_opts___local *, u32) __ksym;
> +struct nf_conn *bpf_skb_ct_add(struct __sk_buff *, struct bpf_sock_tuple *, u32,
> +			       struct bpf_ct_opts___local *, u32) __ksym;
>   struct nf_conn *bpf_skb_ct_lookup(struct __sk_buff *, struct bpf_sock_tuple *, u32,
>   				  struct bpf_ct_opts___local *, u32) __ksym;
>   void bpf_ct_release(struct nf_conn *) __ksym;
> +void bpf_ct_refresh_timeout(struct nf_conn *, u32) __ksym;
>   
>   static __always_inline void
> -nf_ct_test(struct nf_conn *(*func)(void *, struct bpf_sock_tuple *, u32,
> -				   struct bpf_ct_opts___local *, u32),
> +nf_ct_test(struct nf_conn *(*look_fn)(void *, struct bpf_sock_tuple *, u32,
> +				      struct bpf_ct_opts___local *, u32),
> +	   struct nf_conn *(*add_fn)(void *, struct bpf_sock_tuple *, u32,
> +				     struct bpf_ct_opts___local *, u32),
>   	   void *ctx)
>   {
>   	struct bpf_ct_opts___local opts_def = { .l4proto = IPPROTO_TCP, .netns_id = -1 };
>   	struct bpf_sock_tuple bpf_tuple;
>   	struct nf_conn *ct;
> +	int err;
>   
>   	__builtin_memset(&bpf_tuple, 0, sizeof(bpf_tuple.ipv4));
>   
> -	ct = func(ctx, NULL, 0, &opts_def, sizeof(opts_def));
> +	ct = look_fn(ctx, NULL, 0, &opts_def, sizeof(opts_def));
>   	if (ct)
>   		bpf_ct_release(ct);
>   	else
>   		test_einval_bpf_tuple = opts_def.error;
>   
>   	opts_def.reserved[0] = 1;
> -	ct = func(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def, sizeof(opts_def));
> +	ct = look_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)
> @@ -59,21 +74,24 @@ nf_ct_test(struct nf_conn *(*func)(void *, struct bpf_sock_tuple *, u32,
>   		test_einval_reserved = opts_def.error;
>   
>   	opts_def.netns_id = -2;
> -	ct = func(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def, sizeof(opts_def));
> +	ct = look_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> +		     sizeof(opts_def));
>   	opts_def.netns_id = -1;
>   	if (ct)
>   		bpf_ct_release(ct);
>   	else
>   		test_einval_netns_id = opts_def.error;
>   
> -	ct = func(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def, sizeof(opts_def) - 1);
> +	ct = look_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> +		     sizeof(opts_def) - 1);
>   	if (ct)
>   		bpf_ct_release(ct);
>   	else
>   		test_einval_len_opts = opts_def.error;
>   
>   	opts_def.l4proto = IPPROTO_ICMP;
> -	ct = func(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def, sizeof(opts_def));
> +	ct = look_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> +		     sizeof(opts_def));
>   	opts_def.l4proto = IPPROTO_TCP;
>   	if (ct)
>   		bpf_ct_release(ct);
> @@ -81,37 +99,67 @@ nf_ct_test(struct nf_conn *(*func)(void *, struct bpf_sock_tuple *, u32,
>   		test_eproto_l4proto = opts_def.error;
>   
>   	opts_def.netns_id = 0xf00f;
> -	ct = func(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def, sizeof(opts_def));
> +	ct = look_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> +		     sizeof(opts_def));
>   	opts_def.netns_id = -1;
>   	if (ct)
>   		bpf_ct_release(ct);
>   	else
>   		test_enonet_netns_id = opts_def.error;
>   
> -	ct = func(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def, sizeof(opts_def));
> +	ct = look_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> +		     sizeof(opts_def));
>   	if (ct)
>   		bpf_ct_release(ct);
>   	else
>   		test_enoent_lookup = opts_def.error;
>   
> -	ct = func(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4) - 1, &opts_def, sizeof(opts_def));
> +	ct = look_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4) - 1, &opts_def,
> +		     sizeof(opts_def));
>   	if (ct)
>   		bpf_ct_release(ct);
>   	else
>   		test_eafnosupport = opts_def.error;
> +
> +	bpf_tuple.ipv4.saddr = bpf_get_prandom_u32(); /* src IP */
> +	bpf_tuple.ipv4.daddr = bpf_get_prandom_u32(); /* dst IP */
> +	bpf_tuple.ipv4.sport = bpf_htons(bpf_get_prandom_u32()); /* src port */
> +	bpf_tuple.ipv4.dport = bpf_htons(bpf_get_prandom_u32()); /* dst port */

Since it is already random number, bpf_htons is not needed here.
bpf_endian.h can also be removed.

> +
> +	ct = add_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> +		    sizeof(opts_def));
> +	if (ct) {
> +		struct nf_conn *ct_lk;
> +
> +		ct_lk = look_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4),
> +				&opts_def, sizeof(opts_def));
> +		if (ct_lk) {
> +			/* update ct entry timeout */
> +			bpf_ct_refresh_timeout(ct_lk, 10000);
> +			test_delta_timeout = ct_lk->timeout - bpf_jiffies64();
> +			test_delta_timeout /= CONFIG_HZ;
> +			bpf_ct_release(ct_lk);
> +		} else {
> +			test_succ_lookup = opts_def.error;
> +		}
> +		bpf_ct_release(ct);
> +	} else {
> +		test_add_entry = opts_def.error;
> +		test_succ_lookup = opts_def.error;
> +	}
>   }
>   
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