Make sure a new flow dissector program can be attached to replace the old
one with a single syscall. Also check that attaching the same program twice
is prohibited.
Signed-off-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
---
.../bpf/prog_tests/flow_dissector_reattach.c | 93 +++++++++++++++++++
1 file changed, 93 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/flow_dissector_reattach.c
diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector_reattach.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector_reattach.c
new file mode 100644
index 000000000000..0f0006c93956
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector_reattach.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test that the flow_dissector program can be updated with a single
+ * syscall by attaching a new program that replaces the existing one.
+ *
+ * Corner case - the same program cannot be attached twice.
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#include <linux/bpf.h>
+#include <bpf/bpf.h>
+
+#include "test_progs.h"
+
+/* Not used here. For CHECK macro sake only. */
+static int duration;
+
+static bool is_attached(void)
+{
+ bool attached = true;
+ int err, net_fd = -1;
+ __u32 cnt;
+
+ net_fd = open("/proc/self/ns/net", O_RDONLY);
+ if (net_fd < 0)
+ goto out;
+
+ err = bpf_prog_query(net_fd, BPF_FLOW_DISSECTOR, 0, NULL, NULL, &cnt);
+ if (CHECK(err, "bpf_prog_query", "ret %d errno %d\n", err, errno))
+ goto out;
+
+ attached = (cnt > 0);
+out:
+ close(net_fd);
+ return attached;
+}
+
+static int load_prog(void)
+{
+ struct bpf_insn prog[] = {
+ BPF_MOV64_IMM(BPF_REG_0, BPF_OK),
+ BPF_EXIT_INSN(),
+ };
+ int fd;
+
+ fd = bpf_load_program(BPF_PROG_TYPE_FLOW_DISSECTOR, prog,
+ ARRAY_SIZE(prog), "GPL", 0, NULL, 0);
+ CHECK(fd < 0, "bpf_load_program", "ret %d errno %d\n", fd, errno);
+
+ return fd;
+}
+
+void test_flow_dissector_reattach(void)
+{
+ int prog_fd[2] = { -1, -1 };
+ int err;
+
+ if (is_attached())
+ return;
+
+ prog_fd[0] = load_prog();
+ if (prog_fd[0] < 0)
+ return;
+
+ prog_fd[1] = load_prog();
+ if (prog_fd[1] < 0)
+ goto out_close;
+
+ err = bpf_prog_attach(prog_fd[0], 0, BPF_FLOW_DISSECTOR, 0);
+ if (CHECK(err, "bpf_prog_attach-0", "ret %d errno %d\n", err, errno))
+ goto out_close;
+
+ /* Expect success when attaching a different program */
+ err = bpf_prog_attach(prog_fd[1], 0, BPF_FLOW_DISSECTOR, 0);
+ if (CHECK(err, "bpf_prog_attach-1", "ret %d errno %d\n", err, errno))
+ goto out_detach;
+
+ /* Expect failure when attaching the same program twice */
+ err = bpf_prog_attach(prog_fd[1], 0, BPF_FLOW_DISSECTOR, 0);
+ CHECK(!err || errno != EINVAL, "bpf_prog_attach-2",
+ "ret %d errno %d\n", err, errno);
+
+out_detach:
+ err = bpf_prog_detach(0, BPF_FLOW_DISSECTOR);
+ CHECK(err, "bpf_prog_detach", "ret %d errno %d\n", err, errno);
+
+out_close:
+ close(prog_fd[1]);
+ close(prog_fd[0]);
+}
--
2.20.1
