selftests/bpf: add sockopt test that exercises BPF_F_ALLOW_MULTI
sockopt test that verifies chaining behavior.
v9:
* setsockopt chaining example
v7:
* rework the test to verify cgroup getsockopt chaining
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/tools/testing/selftests/bpf/test_sockopt_multi.c b/tools/testing/selftests/bpf/test_sockopt_multi.c
new file mode 100644
index 0000000..4be3441
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_sockopt_multi.c
@@ -0,0 +1,374 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <error.h>
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include <linux/filter.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "bpf_rlimit.h"
+#include "bpf_util.h"
+#include "cgroup_helpers.h"
+
+static int prog_attach(struct bpf_object *obj, int cgroup_fd, const char *title)
+{
+ enum bpf_attach_type attach_type;
+ enum bpf_prog_type prog_type;
+ struct bpf_program *prog;
+ int err;
+
+ err = libbpf_prog_type_by_name(title, &prog_type, &attach_type);
+ if (err) {
+ log_err("Failed to deduct types for %s BPF program", title);
+ return -1;
+ }
+
+ prog = bpf_object__find_program_by_title(obj, title);
+ if (!prog) {
+ log_err("Failed to find %s BPF program", title);
+ return -1;
+ }
+
+ err = bpf_prog_attach(bpf_program__fd(prog), cgroup_fd,
+ attach_type, BPF_F_ALLOW_MULTI);
+ if (err) {
+ log_err("Failed to attach %s BPF program", title);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int prog_detach(struct bpf_object *obj, int cgroup_fd, const char *title)
+{
+ enum bpf_attach_type attach_type;
+ enum bpf_prog_type prog_type;
+ struct bpf_program *prog;
+ int err;
+
+ err = libbpf_prog_type_by_name(title, &prog_type, &attach_type);
+ if (err)
+ return -1;
+
+ prog = bpf_object__find_program_by_title(obj, title);
+ if (!prog)
+ return -1;
+
+ err = bpf_prog_detach2(bpf_program__fd(prog), cgroup_fd,
+ attach_type);
+ if (err)
+ return -1;
+
+ return 0;
+}
+
+static int run_getsockopt_test(struct bpf_object *obj, int cg_parent,
+ int cg_child, int sock_fd)
+{
+ socklen_t optlen;
+ __u8 buf;
+ int err;
+
+ /* Set IP_TOS to the expected value (0x80). */
+
+ buf = 0x80;
+ err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
+ if (err < 0) {
+ log_err("Failed to call setsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ if (buf != 0x80) {
+ log_err("Unexpected getsockopt 0x%x != 0x80 without BPF", buf);
+ err = -1;
+ goto detach;
+ }
+
+ /* Attach child program and make sure it returns new value:
+ * - kernel: -> 0x80
+ * - child: 0x80 -> 0x90
+ */
+
+ err = prog_attach(obj, cg_child, "cgroup/getsockopt/child");
+ if (err)
+ goto detach;
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ if (buf != 0x90) {
+ log_err("Unexpected getsockopt 0x%x != 0x90", buf);
+ err = -1;
+ goto detach;
+ }
+
+ /* Attach parent program and make sure it returns new value:
+ * - kernel: -> 0x80
+ * - child: 0x80 -> 0x90
+ * - parent: 0x90 -> 0xA0
+ */
+
+ err = prog_attach(obj, cg_parent, "cgroup/getsockopt/parent");
+ if (err)
+ goto detach;
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ if (buf != 0xA0) {
+ log_err("Unexpected getsockopt 0x%x != 0xA0", buf);
+ err = -1;
+ goto detach;
+ }
+
+ /* Setting unexpected initial sockopt should return EPERM:
+ * - kernel: -> 0x40
+ * - child: unexpected 0x40, EPERM
+ * - parent: unexpected 0x40, EPERM
+ */
+
+ buf = 0x40;
+ if (setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1) < 0) {
+ log_err("Failed to call setsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (!err) {
+ log_err("Unexpected success from getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ /* Detach child program and make sure we still get EPERM:
+ * - kernel: -> 0x40
+ * - parent: unexpected 0x40, EPERM
+ */
+
+ err = prog_detach(obj, cg_child, "cgroup/getsockopt/child");
+ if (err) {
+ log_err("Failed to detach child program");
+ goto detach;
+ }
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (!err) {
+ log_err("Unexpected success from getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ /* Set initial value to the one the parent program expects:
+ * - kernel: -> 0x90
+ * - parent: 0x90 -> 0xA0
+ */
+
+ buf = 0x90;
+ err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
+ if (err < 0) {
+ log_err("Failed to call setsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ if (buf != 0xA0) {
+ log_err("Unexpected getsockopt 0x%x != 0xA0", buf);
+ err = -1;
+ goto detach;
+ }
+
+detach:
+ prog_detach(obj, cg_child, "cgroup/getsockopt/child");
+ prog_detach(obj, cg_parent, "cgroup/getsockopt/parent");
+
+ return err;
+}
+
+static int run_setsockopt_test(struct bpf_object *obj, int cg_parent,
+ int cg_child, int sock_fd)
+{
+ socklen_t optlen;
+ __u8 buf;
+ int err;
+
+ /* Set IP_TOS to the expected value (0x80). */
+
+ buf = 0x80;
+ err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
+ if (err < 0) {
+ log_err("Failed to call setsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ if (buf != 0x80) {
+ log_err("Unexpected getsockopt 0x%x != 0x80 without BPF", buf);
+ err = -1;
+ goto detach;
+ }
+
+ /* Attach child program and make sure it adds 0x10. */
+
+ err = prog_attach(obj, cg_child, "cgroup/setsockopt");
+ if (err)
+ goto detach;
+
+ buf = 0x80;
+ err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
+ if (err < 0) {
+ log_err("Failed to call setsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ if (buf != 0x80 + 0x10) {
+ log_err("Unexpected getsockopt 0x%x != 0x80 + 0x10", buf);
+ err = -1;
+ goto detach;
+ }
+
+ /* Attach parent program and make sure it adds another 0x10. */
+
+ err = prog_attach(obj, cg_parent, "cgroup/setsockopt");
+ if (err)
+ goto detach;
+
+ buf = 0x80;
+ err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
+ if (err < 0) {
+ log_err("Failed to call setsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ buf = 0x00;
+ optlen = 1;
+ err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
+ if (err) {
+ log_err("Failed to call getsockopt(IP_TOS)");
+ goto detach;
+ }
+
+ if (buf != 0x80 + 2 * 0x10) {
+ log_err("Unexpected getsockopt 0x%x != 0x80 + 2 * 0x10", buf);
+ err = -1;
+ goto detach;
+ }
+
+detach:
+ prog_detach(obj, cg_child, "cgroup/setsockopt");
+ prog_detach(obj, cg_parent, "cgroup/setsockopt");
+
+ return err;
+}
+
+int main(int argc, char **argv)
+{
+ struct bpf_prog_load_attr attr = {
+ .file = "./sockopt_multi.o",
+ };
+ int cg_parent = -1, cg_child = -1;
+ struct bpf_object *obj = NULL;
+ int sock_fd = -1;
+ int err = -1;
+ int ignored;
+
+ if (setup_cgroup_environment()) {
+ log_err("Failed to setup cgroup environment\n");
+ goto out;
+ }
+
+ cg_parent = create_and_get_cgroup("/parent");
+ if (cg_parent < 0) {
+ log_err("Failed to create cgroup /parent\n");
+ goto out;
+ }
+
+ cg_child = create_and_get_cgroup("/parent/child");
+ if (cg_child < 0) {
+ log_err("Failed to create cgroup /parent/child\n");
+ goto out;
+ }
+
+ if (join_cgroup("/parent/child")) {
+ log_err("Failed to join cgroup /parent/child\n");
+ goto out;
+ }
+
+ err = bpf_prog_load_xattr(&attr, &obj, &ignored);
+ if (err) {
+ log_err("Failed to load BPF object");
+ goto out;
+ }
+
+ sock_fd = socket(AF_INET, SOCK_STREAM, 0);
+ if (sock_fd < 0) {
+ log_err("Failed to create socket");
+ goto out;
+ }
+
+ if (run_getsockopt_test(obj, cg_parent, cg_child, sock_fd))
+ err = -1;
+ printf("test_sockopt_multi: getsockopt %s\n",
+ err ? "FAILED" : "PASSED");
+
+ if (run_setsockopt_test(obj, cg_parent, cg_child, sock_fd))
+ err = -1;
+ printf("test_sockopt_multi: setsockopt %s\n",
+ err ? "FAILED" : "PASSED");
+
+out:
+ close(sock_fd);
+ bpf_object__close(obj);
+ close(cg_child);
+ close(cg_parent);
+
+ printf("test_sockopt_multi: %s\n", err ? "FAILED" : "PASSED");
+ return err ? EXIT_FAILURE : EXIT_SUCCESS;
+}
