Re: [PATCH bpf-next v3 9/9] selftests/bpf: Add test for unstable CT lookup API

Maxim Mikityanskiy
2021-12-14T14:13:53Z

On 2021-12-10 15:02, Kumar Kartikeya Dwivedi wrote:
> This tests that we return errors as documented, and also that the kfunc
> calls work from both XDP and TC hooks.
>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> ---
> tools/testing/selftests/bpf/config | 4 +
> .../testing/selftests/bpf/prog_tests/bpf_nf.c | 48 ++++++++
> .../testing/selftests/bpf/progs/test_bpf_nf.c | 113 ++++++++++++++++++
> 3 files changed, 165 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> create mode 100644 tools/testing/selftests/bpf/progs/test_bpf_nf.c
>
> diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
> index 5192305159ec..4a2a47fcd6ef 100644
> --- a/tools/testing/selftests/bpf/config
> +++ b/tools/testing/selftests/bpf/config
> @@ -46,3 +46,7 @@ CONFIG_IMA_READ_POLICY=y
> CONFIG_BLK_DEV_LOOP=y
> CONFIG_FUNCTION_TRACER=y
> CONFIG_DYNAMIC_FTRACE=y
> +CONFIG_NETFILTER=y
> +CONFIG_NF_DEFRAG_IPV4=y
> +CONFIG_NF_DEFRAG_IPV6=y
> +CONFIG_NF_CONNTRACK=y
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> new file mode 100644
> index 000000000000..56e8d745b8c8
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <test_progs.h>
> +#include <network_helpers.h>
> +#include "test_bpf_nf.skel.h"
> +
> +enum {
> + TEST_XDP,
> + TEST_TC_BPF,
> +};
> +
> +void test_bpf_nf_ct(int mode)
> +{
> + struct test_bpf_nf *skel;
> + int prog_fd, err, retval;
> +
> + skel = test_bpf_nf__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "test_bpf_nf__open_and_load"))
> + return;
> +
> + if (mode == TEST_XDP)
> + prog_fd = bpf_program__fd(skel->progs.nf_xdp_ct_test);
> + else
> + prog_fd = bpf_program__fd(skel->progs.nf_skb_ct_test);
> +
> + err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4), NULL, NULL,
> + (__u32 *)&retval, NULL);
> + if (!ASSERT_OK(err, "bpf_prog_test_run"))
> + 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");
> + 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");
> +end:
> + test_bpf_nf__destroy(skel);
> +}
> +
> +void test_bpf_nf(void)
> +{
> + if (test__start_subtest("xdp-ct"))
> + test_bpf_nf_ct(TEST_XDP);
> + if (test__start_subtest("tc-bpf-ct"))
> + test_bpf_nf_ct(TEST_TC_BPF);
> +}
> diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> new file mode 100644
> index 000000000000..7cfff245b24f
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> @@ -0,0 +1,113 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <vmlinux.h>
> +#include <bpf/bpf_helpers.h>
> +
> +#define EAFNOSUPPORT 97
> +#define EPROTO 71
> +#define ENONET 64
> +#define EINVAL 22
> +#define ENOENT 2
> +
> +int test_einval_bpf_tuple = 0;
> +int test_einval_reserved = 0;
> +int test_einval_netns_id = 0;
> +int test_einval_len_opts = 0;
> +int test_eproto_l4proto = 0;
> +int test_enonet_netns_id = 0;
> +int test_enoent_lookup = 0;
> +int test_eafnosupport = 0;
> +
> +struct nf_conn *bpf_xdp_ct_lookup(struct xdp_md *, struct bpf_sock_tuple *, u32,
> + struct bpf_ct_opts *, u32) __weak __ksym;
> +struct nf_conn *bpf_skb_ct_lookup(struct __sk_buff *, struct bpf_sock_tuple *, u32,
> + struct bpf_ct_opts *, u32) __weak __ksym;
> +void bpf_ct_release(struct nf_conn *) __weak __ksym;
> +
> +#define nf_ct_test(func, ctx) \
> + ({ \
> + struct bpf_ct_opts opts_def = { .l4proto = IPPROTO_TCP, \
> + .netns_id = -1 }; \

I noticed that when CONFIG_NF_CONNTRACK=m, struct bpf_ct_opts doesn't
get added to vmlinux.h. What is the right way to get definitions of
structs from modules in BPF programs? Are they supposed to be part of
vmlinux.h?

> + struct bpf_sock_tuple bpf_tuple; \
> + struct nf_conn *ct; \
> + \
> + __builtin_memset(&bpf_tuple, 0, sizeof(bpf_tuple.ipv4)); \
> + ct = func(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)); \
> + opts_def.reserved[0] = 0; \
> + opts_def.l4proto = IPPROTO_TCP; \
> + if (ct) \
> + bpf_ct_release(ct); \
> + else \
> + 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)); \
> + 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); \
> + 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)); \
> + opts_def.l4proto = IPPROTO_TCP; \
> + if (ct) \
> + bpf_ct_release(ct); \
> + else \
> + 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)); \
> + 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)); \
> + 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)); \
> + if (ct) \
> + bpf_ct_release(ct); \
> + else \
> + test_eafnosupport = opts_def.error; \
> + })
> +
> +SEC("xdp")
> +int nf_xdp_ct_test(struct xdp_md *ctx)
> +{
> + nf_ct_test(bpf_xdp_ct_lookup, ctx);
> + return 0;
> +}
> +
> +SEC("tc")
> +int nf_skb_ct_test(struct __sk_buff *ctx)
> +{
> + nf_ct_test(bpf_skb_ct_lookup, ctx);
> + return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";