1 files changed, 70 insertions, 0 deletions
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..2643d896ddae
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/udp_limit.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "udp_limit.skel.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+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 (!ASSERT_GE(cgroup_fd, 0, "cg-join"))
+		return;
+
+	skel = udp_limit__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel-load"))
+		goto close_cgroup_fd;
+
+	skel->links.sock = bpf_program__attach_cgroup(skel->progs.sock, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.sock, "cg_attach_sock"))
+		goto close_skeleton;
+	skel->links.sock_release = bpf_program__attach_cgroup(skel->progs.sock_release, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.sock_release, "cg_attach_sock_release"))
+		goto close_skeleton;
+
+	/* BPF program enforces a single UDP socket per cgroup,
+	 * verify that.
+	 */
+	fd1 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (!ASSERT_GE(fd1, 0, "socket(fd1)"))
+		goto close_skeleton;
+
+	fd2 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (!ASSERT_LT(fd2, 0, "socket(fd2)"))
+		goto close_skeleton;
+
+	/* We can reopen again after close. */
+	close(fd1);
+	fd1 = -1;
+
+	fd1 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (!ASSERT_GE(fd1, 0, "socket(fd1-again)"))
+		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 (!ASSERT_EQ(skel->bss->invocations, 4, "bss-invocations"))
+		goto close_skeleton;
+
+	/* We should still have a single socket in use */
+	if (!ASSERT_EQ(skel->bss->in_use, 1, "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);
+}