Re: [PATCH bpf-next v3 1/3] selftests/bpf: Add existing connection bpf_*_ct_lookup() test

[Kumar Kartikeya Dwivedi]

On Thu, 11 Aug 2022 at 01:16, Daniel Xu <dxu@xxxxxxxxx> wrote:
>
> Add a test where we do a conntrack lookup on an existing connection.
> This is nice because it's a more realistic test than artifically
> creating a ct entry and looking it up afterwards.
>
> Signed-off-by: Daniel Xu <dxu@xxxxxxxxx>
> ---
>  .../testing/selftests/bpf/prog_tests/bpf_nf.c | 59 +++++++++++++++++++
>  .../testing/selftests/bpf/progs/test_bpf_nf.c | 18 ++++++
>  2 files changed, 77 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> index 7a74a1579076..317978cac029 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> @@ -24,10 +24,34 @@ enum {
>         TEST_TC_BPF,
>  };
>
> +#define TIMEOUT_MS 3000
> +
> +static int connect_to_server(int srv_fd)
> +{
> +       int fd = -1;
> +
> +       fd = socket(AF_INET, SOCK_STREAM, 0);
> +       if (!ASSERT_GE(fd, 0, "socket"))
> +               goto out;
> +
> +       if (CHECK_FAIL(connect_fd_to_fd(fd, srv_fd, TIMEOUT_MS))) {

CHECK_FAIL is deprecated, please consider using ASSERT_*. Sorry for
not catching this before your respin...

> +               close(fd);
> +               fd = -1;
> +       }
> +out:
> +       return fd;
> +}
> +
>  static void test_bpf_nf_ct(int mode)
>  {
> +       const char *iptables = "iptables -t raw %s PREROUTING -j CT";
> +       int srv_fd = -1, client_fd = -1, srv_client_fd = -1;
> +       struct sockaddr_in peer_addr = {};
>         struct test_bpf_nf *skel;
>         int prog_fd, err;
> +       socklen_t len;
> +       u16 srv_port;
> +       char cmd[64];
>         LIBBPF_OPTS(bpf_test_run_opts, topts,
>                 .data_in = &pkt_v4,
>                 .data_size_in = sizeof(pkt_v4),
> @@ -38,6 +62,32 @@ static void test_bpf_nf_ct(int mode)
>         if (!ASSERT_OK_PTR(skel, "test_bpf_nf__open_and_load"))
>                 return;
>
> +       /* Enable connection tracking */
> +       snprintf(cmd, sizeof(cmd), iptables, "-A");
> +       if (!ASSERT_OK(system(cmd), "iptables"))
> +               goto end;
> +
> +       srv_port = (mode == TEST_XDP) ? 5005 : 5006;
> +       srv_fd = start_server(AF_INET, SOCK_STREAM, "127.0.0.1", srv_port, TIMEOUT_MS);
> +       if (!ASSERT_GE(srv_fd, 0, "start_server"))
> +               goto end;
> +
> +       client_fd = connect_to_server(srv_fd);
> +       if (!ASSERT_GE(client_fd, 0, "connect_to_server"))
> +               goto end;
> +
> +       len = sizeof(peer_addr);
> +       srv_client_fd = accept(srv_fd, (struct sockaddr *)&peer_addr, &len);
> +       if (!ASSERT_GE(srv_client_fd, 0, "accept"))
> +               goto end;
> +       if (!ASSERT_EQ(len, sizeof(struct sockaddr_in), "sockaddr len"))
> +               goto end;
> +
> +       skel->bss->saddr = peer_addr.sin_addr.s_addr;
> +       skel->bss->sport = peer_addr.sin_port;
> +       skel->bss->daddr = peer_addr.sin_addr.s_addr;
> +       skel->bss->dport = htons(srv_port);
> +
>         if (mode == TEST_XDP)
>                 prog_fd = bpf_program__fd(skel->progs.nf_xdp_ct_test);
>         else
> @@ -63,7 +113,16 @@ static void test_bpf_nf_ct(int mode)
>         ASSERT_LE(skel->bss->test_delta_timeout, 10, "Test for max ct timeout update");
>         /* 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");
>  end:
> +       if (srv_client_fd != -1)
> +               close(srv_client_fd);
> +       if (client_fd != -1)
> +               close(client_fd);
> +       if (srv_fd != -1)
> +               close(srv_fd);
> +       snprintf(cmd, sizeof(cmd), iptables, "-D");
> +       system(cmd);
>         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 196cd8dfe42a..84e0fd479794 100644
> --- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> +++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
> @@ -23,6 +23,11 @@ int test_insert_entry = -EAFNOSUPPORT;
>  int test_succ_lookup = -ENOENT;
>  u32 test_delta_timeout = 0;
>  u32 test_status = 0;
> +__be32 saddr = 0;
> +__be16 sport = 0;
> +__be32 daddr = 0;
> +__be16 dport = 0;
> +int test_exist_lookup = -ENOENT;
>
>  struct nf_conn;
>
> @@ -160,6 +165,19 @@ nf_ct_test(struct nf_conn *(*lookup_fn)(void *, struct bpf_sock_tuple *, u32,
>                 }
>                 test_alloc_entry = 0;
>         }
> +
> +       bpf_tuple.ipv4.saddr = saddr;
> +       bpf_tuple.ipv4.daddr = daddr;
> +       bpf_tuple.ipv4.sport = sport;
> +       bpf_tuple.ipv4.dport = dport;
> +       ct = lookup_fn(ctx, &bpf_tuple, sizeof(bpf_tuple.ipv4), &opts_def,
> +                      sizeof(opts_def));
> +       if (ct) {
> +               test_exist_lookup = 0;
> +               bpf_ct_release(ct);
> +       } else {
> +               test_exist_lookup = opts_def.error;
> +       }
>  }
>
>  SEC("xdp")
> --
> 2.37.1
>