On 7/7/20 1:01 AM, Stanislav Fomichev wrote:
Simple test that enforces a single SOCK_DGRAM socker per cgroup.
Signed-off-by: Stanislav Fomichev <[email protected]>
---
.../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 000000000000..2aba09d4d01b
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/udp_limit.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "udp_limit.skel.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+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 000000000000..edbb30a27e63
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/udp_limit.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <sys/socket.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+int invocations = 0, in_use = 0;
+
+SEC("cgroup/sock")
nit: Doesn't matter overly much, but given you've added `cgroup/sock_create`
earlier in patch 2/4 intention was probably to use it as well. But either is
fine as it resolved to the same.
+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;
+}
