From d95b49ecc38ef609e94b5ec602e4e77bce8e557f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Wed, 14 Dec 2022 02:05:16 +0100 Subject: [PATCH] selftests/bpf: Add a test for using a cpumap from an freplace-to-XDP program MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds a simple test for inserting an XDP program into a cpumap that is "owned" by an XDP program that was loaded as PROG_TYPE_EXT (as libxdp does). Prior to the kernel fix this would fail because the map type ownership would be set to PROG_TYPE_EXT instead of being resolved to PROG_TYPE_XDP. v4: - Use skeletons for selftest v3: - Update comment to better explain the cause - Add Yonghong's ACK Acked-by: Yonghong Song Signed-off-by: Toke Høiland-Jørgensen --- .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 54 +++++++++++++++++++ .../selftests/bpf/progs/freplace_progmap.c | 24 +++++++++ 2 files changed, 78 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/freplace_progmap.c diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c index d1e32e792536c..efa1fc65840de 100644 --- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c +++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c @@ -4,6 +4,8 @@ #include #include #include "bind4_prog.skel.h" +#include "freplace_progmap.skel.h" +#include "xdp_dummy.skel.h" typedef int (*test_cb)(struct bpf_object *obj); @@ -500,6 +502,56 @@ static void test_fentry_to_cgroup_bpf(void) bind4_prog__destroy(skel); } +static void test_func_replace_progmap(void) +{ + struct bpf_cpumap_val value = { .qsize = 1 }; + struct freplace_progmap *skel = NULL; + struct xdp_dummy *tgt_skel = NULL; + int err, tgt_fd; + __u32 key = 0; + + skel = freplace_progmap__open(); + if (!ASSERT_OK_PTR(skel, "prog_open")) + return; + + tgt_skel = xdp_dummy__open_and_load(); + if (!ASSERT_OK_PTR(tgt_skel, "tgt_prog_load")) + goto out; + + tgt_fd = bpf_program__fd(tgt_skel->progs.xdp_dummy_prog); + + /* Change the 'redirect' program type to be a PROG_TYPE_EXT + * with an XDP target + */ + bpf_program__set_type(skel->progs.xdp_cpumap_prog, BPF_PROG_TYPE_EXT); + bpf_program__set_expected_attach_type(skel->progs.xdp_cpumap_prog, 0); + err = bpf_program__set_attach_target(skel->progs.xdp_cpumap_prog, + tgt_fd, "xdp_dummy_prog"); + if (!ASSERT_OK(err, "set_attach_target")) + goto out; + + err = freplace_progmap__load(skel); + if (!ASSERT_OK(err, "obj_load")) + goto out; + + /* Prior to fixing the kernel, loading the PROG_TYPE_EXT 'redirect' + * program above will cause the map owner type of 'cpumap' to be set to + * PROG_TYPE_EXT. This in turn will cause the bpf_map_update_elem() + * below to fail, because the program we are inserting into the map is + * of PROG_TYPE_XDP. After fixing the kernel, the initial ownership will + * be correctly resolved to the *target* of the PROG_TYPE_EXT program + * (i.e., PROG_TYPE_XDP) and the map update will succeed. + */ + value.bpf_prog.fd = bpf_program__fd(skel->progs.xdp_drop_prog); + err = bpf_map_update_elem(bpf_map__fd(skel->maps.cpu_map), + &key, &value, 0); + ASSERT_OK(err, "map_update"); + +out: + xdp_dummy__destroy(tgt_skel); + freplace_progmap__destroy(skel); +} + /* NOTE: affect other tests, must run in serial mode */ void serial_test_fexit_bpf2bpf(void) { @@ -525,4 +577,6 @@ void serial_test_fexit_bpf2bpf(void) test_func_replace_global_func(); if (test__start_subtest("fentry_to_cgroup_bpf")) test_fentry_to_cgroup_bpf(); + if (test__start_subtest("func_replace_progmap")) + test_func_replace_progmap(); } diff --git a/tools/testing/selftests/bpf/progs/freplace_progmap.c b/tools/testing/selftests/bpf/progs/freplace_progmap.c new file mode 100644 index 0000000000000..68174c3d7b371 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/freplace_progmap.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +struct { + __uint(type, BPF_MAP_TYPE_CPUMAP); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(struct bpf_cpumap_val)); + __uint(max_entries, 1); +} cpu_map SEC(".maps"); + +SEC("xdp/cpumap") +int xdp_drop_prog(struct xdp_md *ctx) +{ + return XDP_DROP; +} + +SEC("xdp") +int xdp_cpumap_prog(struct xdp_md *ctx) +{ + return bpf_redirect_map(&cpu_map, 0, XDP_PASS); +} + +char _license[] SEC("license") = "GPL";