libbpf: Add selftests for TC-BPF management API

This adds some basic tests for the low level bpf_tc_* API.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210512103451.989420-4-memxor@gmail.com

tools/testing/selftests/bpf/prog_tests/tc_bpf.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include <linux/pkt_cls.h>
+
+#include "test_tc_bpf.skel.h"
+
+#define LO_IFINDEX 1
+
+#define TEST_DECLARE_OPTS(__fd)                                                                   \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_h, .handle = 1);                                     \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_p, .priority = 1);                                   \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_f, .prog_fd = __fd);                                 \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_hp, .handle = 1, .priority = 1);                     \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_hf, .handle = 1, .prog_fd = __fd);                   \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_pf, .priority = 1, .prog_fd = __fd);                 \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_hpf, .handle = 1, .priority = 1, .prog_fd = __fd);   \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_hpi, .handle = 1, .priority = 1, .prog_id = 42);     \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_hpr, .handle = 1, .priority = 1,                     \
+			    .flags = BPF_TC_F_REPLACE);                                            \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_hpfi, .handle = 1, .priority = 1, .prog_fd = __fd,   \
+			    .prog_id = 42);                                                        \
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts_prio_max, .handle = 1, .priority = UINT16_MAX + 1);
+
+static int test_tc_bpf_basic(const struct bpf_tc_hook *hook, int fd)
+{
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 1, .prog_fd = fd);
+	struct bpf_prog_info info = {};
+	__u32 info_len = sizeof(info);
+	int ret;
+
+	ret = bpf_obj_get_info_by_fd(fd, &info, &info_len);
+	if (!ASSERT_OK(ret, "bpf_obj_get_info_by_fd"))
+		return ret;
+
+	ret = bpf_tc_attach(hook, &opts);
+	if (!ASSERT_OK(ret, "bpf_tc_attach"))
+		return ret;
+
+	if (!ASSERT_EQ(opts.handle, 1, "handle set") ||
+	    !ASSERT_EQ(opts.priority, 1, "priority set") ||
+	    !ASSERT_EQ(opts.prog_id, info.id, "prog_id set"))
+		goto end;
+
+	opts.prog_id = 0;
+	opts.flags = BPF_TC_F_REPLACE;
+	ret = bpf_tc_attach(hook, &opts);
+	if (!ASSERT_OK(ret, "bpf_tc_attach replace mode"))
+		goto end;
+
+	opts.flags = opts.prog_fd = opts.prog_id = 0;
+	ret = bpf_tc_query(hook, &opts);
+	if (!ASSERT_OK(ret, "bpf_tc_query"))
+		goto end;
+
+	if (!ASSERT_EQ(opts.handle, 1, "handle set") ||
+	    !ASSERT_EQ(opts.priority, 1, "priority set") ||
+	    !ASSERT_EQ(opts.prog_id, info.id, "prog_id set"))
+		goto end;
+
+end:
+	opts.flags = opts.prog_fd = opts.prog_id = 0;
+	ret = bpf_tc_detach(hook, &opts);
+	ASSERT_OK(ret, "bpf_tc_detach");
+	return ret;
+}
+
+static int test_tc_bpf_api(struct bpf_tc_hook *hook, int fd)
+{
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, attach_opts, .handle = 1, .priority = 1, .prog_fd = fd);
+	DECLARE_LIBBPF_OPTS(bpf_tc_hook, inv_hook, .attach_point = BPF_TC_INGRESS);
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 1);
+	int ret;
+
+	ret = bpf_tc_hook_create(NULL);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_create invalid hook = NULL"))
+		return -EINVAL;
+
+	/* hook ifindex = 0 */
+	ret = bpf_tc_hook_create(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_create invalid hook ifindex == 0"))
+		return -EINVAL;
+
+	ret = bpf_tc_hook_destroy(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_destroy invalid hook ifindex == 0"))
+		return -EINVAL;
+
+	ret = bpf_tc_attach(&inv_hook, &attach_opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid hook ifindex == 0"))
+		return -EINVAL;
+	attach_opts.prog_id = 0;
+
+	ret = bpf_tc_detach(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid hook ifindex == 0"))
+		return -EINVAL;
+
+	ret = bpf_tc_query(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid hook ifindex == 0"))
+		return -EINVAL;
+
+	/* hook ifindex < 0 */
+	inv_hook.ifindex = -1;
+
+	ret = bpf_tc_hook_create(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_create invalid hook ifindex < 0"))
+		return -EINVAL;
+
+	ret = bpf_tc_hook_destroy(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_destroy invalid hook ifindex < 0"))
+		return -EINVAL;
+
+	ret = bpf_tc_attach(&inv_hook, &attach_opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid hook ifindex < 0"))
+		return -EINVAL;
+	attach_opts.prog_id = 0;
+
+	ret = bpf_tc_detach(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid hook ifindex < 0"))
+		return -EINVAL;
+
+	ret = bpf_tc_query(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid hook ifindex < 0"))
+		return -EINVAL;
+
+	inv_hook.ifindex = LO_IFINDEX;
+
+	/* hook.attach_point invalid */
+	inv_hook.attach_point = 0xabcd;
+	ret = bpf_tc_hook_create(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_create invalid hook.attach_point"))
+		return -EINVAL;
+
+	ret = bpf_tc_hook_destroy(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_destroy invalid hook.attach_point"))
+		return -EINVAL;
+
+	ret = bpf_tc_attach(&inv_hook, &attach_opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid hook.attach_point"))
+		return -EINVAL;
+
+	ret = bpf_tc_detach(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid hook.attach_point"))
+		return -EINVAL;
+
+	ret = bpf_tc_query(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid hook.attach_point"))
+		return -EINVAL;
+
+	inv_hook.attach_point = BPF_TC_INGRESS;
+
+	/* hook.attach_point valid, but parent invalid */
+	inv_hook.parent = TC_H_MAKE(1UL << 16, 10);
+	ret = bpf_tc_hook_create(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_create invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_hook_destroy(&inv_hook);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_hook_destroy invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_attach(&inv_hook, &attach_opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_detach(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_query(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid hook parent"))
+		return -EINVAL;
+
+	inv_hook.attach_point = BPF_TC_CUSTOM;
+	inv_hook.parent = 0;
+	/* These return EOPNOTSUPP instead of EINVAL as parent is checked after
+	 * attach_point of the hook.
+	 */
+	ret = bpf_tc_hook_create(&inv_hook);
+	if (!ASSERT_EQ(ret, -EOPNOTSUPP, "bpf_tc_hook_create invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_hook_destroy(&inv_hook);
+	if (!ASSERT_EQ(ret, -EOPNOTSUPP, "bpf_tc_hook_destroy invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_attach(&inv_hook, &attach_opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_detach(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid hook parent"))
+		return -EINVAL;
+
+	ret = bpf_tc_query(&inv_hook, &opts);
+	if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid hook parent"))
+		return -EINVAL;
+
+	inv_hook.attach_point = BPF_TC_INGRESS;
+
+	/* detach */
+	{
+		TEST_DECLARE_OPTS(fd);
+
+		ret = bpf_tc_detach(NULL, &opts_hp);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid hook = NULL"))
+			return -EINVAL;
+
+		ret = bpf_tc_detach(hook, NULL);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid opts = NULL"))
+			return -EINVAL;
+
+		ret = bpf_tc_detach(hook, &opts_hpr);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid flags set"))
+			return -EINVAL;
+
+		ret = bpf_tc_detach(hook, &opts_hpf);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid prog_fd set"))
+			return -EINVAL;
+
+		ret = bpf_tc_detach(hook, &opts_hpi);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid prog_id set"))
+			return -EINVAL;
+
+		ret = bpf_tc_detach(hook, &opts_p);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid handle unset"))
+			return -EINVAL;
+
+		ret = bpf_tc_detach(hook, &opts_h);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid priority unset"))
+			return -EINVAL;
+
+		ret = bpf_tc_detach(hook, &opts_prio_max);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_detach invalid priority > UINT16_MAX"))
+			return -EINVAL;
+	}
+
+	/* query */
+	{
+		TEST_DECLARE_OPTS(fd);
+
+		ret = bpf_tc_query(NULL, &opts);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid hook = NULL"))
+			return -EINVAL;
+
+		ret = bpf_tc_query(hook, NULL);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid opts = NULL"))
+			return -EINVAL;
+
+		ret = bpf_tc_query(hook, &opts_hpr);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid flags set"))
+			return -EINVAL;
+
+		ret = bpf_tc_query(hook, &opts_hpf);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid prog_fd set"))
+			return -EINVAL;
+
+		ret = bpf_tc_query(hook, &opts_hpi);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid prog_id set"))
+			return -EINVAL;
+
+		ret = bpf_tc_query(hook, &opts_p);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid handle unset"))
+			return -EINVAL;
+
+		ret = bpf_tc_query(hook, &opts_h);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid priority unset"))
+			return -EINVAL;
+
+		ret = bpf_tc_query(hook, &opts_prio_max);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query invalid priority > UINT16_MAX"))
+			return -EINVAL;
+
+		/* when chain is not present, kernel returns -EINVAL */
+		ret = bpf_tc_query(hook, &opts_hp);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_query valid handle, priority set"))
+			return -EINVAL;
+	}
+
+	/* attach */
+	{
+		TEST_DECLARE_OPTS(fd);
+
+		ret = bpf_tc_attach(NULL, &opts_hp);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid hook = NULL"))
+			return -EINVAL;
+
+		ret = bpf_tc_attach(hook, NULL);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid opts = NULL"))
+			return -EINVAL;
+
+		opts_hp.flags = 42;
+		ret = bpf_tc_attach(hook, &opts_hp);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid flags"))
+			return -EINVAL;
+
+		ret = bpf_tc_attach(hook, NULL);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid prog_fd unset"))
+			return -EINVAL;
+
+		ret = bpf_tc_attach(hook, &opts_hpi);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid prog_id set"))
+			return -EINVAL;
+
+		ret = bpf_tc_attach(hook, &opts_pf);
+		if (!ASSERT_OK(ret, "bpf_tc_attach valid handle unset"))
+			return -EINVAL;
+		opts_pf.prog_fd = opts_pf.prog_id = 0;
+		ASSERT_OK(bpf_tc_detach(hook, &opts_pf), "bpf_tc_detach");
+
+		ret = bpf_tc_attach(hook, &opts_hf);
+		if (!ASSERT_OK(ret, "bpf_tc_attach valid priority unset"))
+			return -EINVAL;
+		opts_hf.prog_fd = opts_hf.prog_id = 0;
+		ASSERT_OK(bpf_tc_detach(hook, &opts_hf), "bpf_tc_detach");
+
+		ret = bpf_tc_attach(hook, &opts_prio_max);
+		if (!ASSERT_EQ(ret, -EINVAL, "bpf_tc_attach invalid priority > UINT16_MAX"))
+			return -EINVAL;
+
+		ret = bpf_tc_attach(hook, &opts_f);
+		if (!ASSERT_OK(ret, "bpf_tc_attach valid both handle and priority unset"))
+			return -EINVAL;
+		opts_f.prog_fd = opts_f.prog_id = 0;
+		ASSERT_OK(bpf_tc_detach(hook, &opts_f), "bpf_tc_detach");
+	}
+
+	return 0;
+}
+
+void test_tc_bpf(void)
+{
+	DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook, .ifindex = LO_IFINDEX,
+			    .attach_point = BPF_TC_INGRESS);
+	struct test_tc_bpf *skel = NULL;
+	bool hook_created = false;
+	int cls_fd, ret;
+
+	skel = test_tc_bpf__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_tc_bpf__open_and_load"))
+		return;
+
+	cls_fd = bpf_program__fd(skel->progs.cls);
+
+	ret = bpf_tc_hook_create(&hook);
+	if (ret == 0)
+		hook_created = true;
+
+	ret = ret == -EEXIST ? 0 : ret;
+	if (!ASSERT_OK(ret, "bpf_tc_hook_create(BPF_TC_INGRESS)"))
+		goto end;
+
+	hook.attach_point = BPF_TC_CUSTOM;
+	hook.parent = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
+	ret = bpf_tc_hook_create(&hook);
+	if (!ASSERT_EQ(ret, -EOPNOTSUPP, "bpf_tc_hook_create invalid hook.attach_point"))
+		goto end;
+
+	ret = test_tc_bpf_basic(&hook, cls_fd);
+	if (!ASSERT_OK(ret, "test_tc_internal ingress"))
+		goto end;
+
+	ret = bpf_tc_hook_destroy(&hook);
+	if (!ASSERT_EQ(ret, -EOPNOTSUPP, "bpf_tc_hook_destroy invalid hook.attach_point"))
+		goto end;
+
+	hook.attach_point = BPF_TC_INGRESS;
+	hook.parent = 0;
+	bpf_tc_hook_destroy(&hook);
+
+	ret = test_tc_bpf_basic(&hook, cls_fd);
+	if (!ASSERT_OK(ret, "test_tc_internal ingress"))
+		goto end;
+
+	bpf_tc_hook_destroy(&hook);
+
+	hook.attach_point = BPF_TC_EGRESS;
+	ret = test_tc_bpf_basic(&hook, cls_fd);
+	if (!ASSERT_OK(ret, "test_tc_internal egress"))
+		goto end;
+
+	bpf_tc_hook_destroy(&hook);
+
+	ret = test_tc_bpf_api(&hook, cls_fd);
+	if (!ASSERT_OK(ret, "test_tc_bpf_api"))
+		goto end;
+
+	bpf_tc_hook_destroy(&hook);
+
+end:
+	if (hook_created) {
+		hook.attach_point = BPF_TC_INGRESS | BPF_TC_EGRESS;
+		bpf_tc_hook_destroy(&hook);
+	}
+	test_tc_bpf__destroy(skel);
+}

tools/testing/selftests/bpf/progs/test_tc_bpf.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+/* Dummy prog to test TC-BPF API */
+
+SEC("classifier")
+int cls(struct __sk_buff *skb)
+{
+	return 0;
+}