From 65ffd797861a44ff97081de1db01e4aef716ed46 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Mon, 6 Jul 2020 16:01:28 -0700 Subject: [PATCH] selftests/bpf: Test BPF_CGROUP_INET_SOCK_RELEASE Simple test that enforces a single SOCK_DGRAM socket per cgroup. Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200706230128.4073544-5-sdf@google.com --- tools/testing/selftests/bpf/prog_tests/udp_limit.c | 75 ++++++++++++++++++++++ tools/testing/selftests/bpf/progs/udp_limit.c | 42 ++++++++++++ 2 files changed, 117 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/udp_limit.c create mode 100644 tools/testing/selftests/bpf/progs/udp_limit.c diff --git a/tools/testing/selftests/bpf/prog_tests/udp_limit.c b/tools/testing/selftests/bpf/prog_tests/udp_limit.c new file mode 100644 index 0000000..2aba09d --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/udp_limit.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include "udp_limit.skel.h" + +#include +#include + +static int duration; + +void test_udp_limit(void) +{ + struct udp_limit *skel; + int fd1 = -1, fd2 = -1; + int cgroup_fd; + + cgroup_fd = test__join_cgroup("/udp_limit"); + if (CHECK(cgroup_fd < 0, "cg-join", "errno %d", errno)) + return; + + skel = udp_limit__open_and_load(); + if (CHECK(!skel, "skel-load", "errno %d", errno)) + goto close_cgroup_fd; + + skel->links.sock = bpf_program__attach_cgroup(skel->progs.sock, cgroup_fd); + skel->links.sock_release = bpf_program__attach_cgroup(skel->progs.sock_release, cgroup_fd); + if (CHECK(IS_ERR(skel->links.sock) || IS_ERR(skel->links.sock_release), + "cg-attach", "sock %ld sock_release %ld", + PTR_ERR(skel->links.sock), + PTR_ERR(skel->links.sock_release))) + goto close_skeleton; + + /* BPF program enforces a single UDP socket per cgroup, + * verify that. + */ + fd1 = socket(AF_INET, SOCK_DGRAM, 0); + if (CHECK(fd1 < 0, "fd1", "errno %d", errno)) + goto close_skeleton; + + fd2 = socket(AF_INET, SOCK_DGRAM, 0); + if (CHECK(fd2 >= 0, "fd2", "errno %d", errno)) + goto close_skeleton; + + /* We can reopen again after close. */ + close(fd1); + fd1 = -1; + + fd1 = socket(AF_INET, SOCK_DGRAM, 0); + if (CHECK(fd1 < 0, "fd1-again", "errno %d", errno)) + goto close_skeleton; + + /* Make sure the program was invoked the expected + * number of times: + * - open fd1 - BPF_CGROUP_INET_SOCK_CREATE + * - attempt to openfd2 - BPF_CGROUP_INET_SOCK_CREATE + * - close fd1 - BPF_CGROUP_INET_SOCK_RELEASE + * - open fd1 again - BPF_CGROUP_INET_SOCK_CREATE + */ + if (CHECK(skel->bss->invocations != 4, "bss-invocations", + "invocations=%d", skel->bss->invocations)) + goto close_skeleton; + + /* We should still have a single socket in use */ + if (CHECK(skel->bss->in_use != 1, "bss-in_use", + "in_use=%d", skel->bss->in_use)) + goto close_skeleton; + +close_skeleton: + if (fd1 >= 0) + close(fd1); + if (fd2 >= 0) + close(fd2); + udp_limit__destroy(skel); +close_cgroup_fd: + close(cgroup_fd); +} diff --git a/tools/testing/selftests/bpf/progs/udp_limit.c b/tools/testing/selftests/bpf/progs/udp_limit.c new file mode 100644 index 0000000..8429b22 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/udp_limit.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include + +int invocations = 0, in_use = 0; + +SEC("cgroup/sock_create") +int sock(struct bpf_sock *ctx) +{ + __u32 key; + + if (ctx->type != SOCK_DGRAM) + return 1; + + __sync_fetch_and_add(&invocations, 1); + + if (in_use > 0) { + /* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called + * when we return an error from the BPF + * program! + */ + return 0; + } + + __sync_fetch_and_add(&in_use, 1); + return 1; +} + +SEC("cgroup/sock_release") +int sock_release(struct bpf_sock *ctx) +{ + __u32 key; + + if (ctx->type != SOCK_DGRAM) + return 1; + + __sync_fetch_and_add(&invocations, 1); + __sync_fetch_and_add(&in_use, -1); + return 1; +} -- 2.7.4