selftests/bpf: Add mprog API tests for BPF tcx opts

Add a big batch of test coverage to assert all aspects of the tcx opts
attach, detach and query API:

  # ./vmtest.sh -- ./test_progs -t tc_opts
  [...]
  + /etc/rcS.d/S50-startup
  ./test_progs -t tc_opts
  [   11.645647] bpf_testmod: loading out-of-tree module taints kernel.
  [   11.647546] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  [   11.710400] tsc: Refined TSC clocksource calibration: 3407.988 MHz
  [   11.712352] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc932722, max_idle_ns: 440795381586 ns
  [   11.715657] clocksource: Switched to clocksource tsc
  torvalds#237     tc_opts_after:OK
  torvalds#238     tc_opts_append:OK
  torvalds#239     tc_opts_basic:OK
  torvalds#240     tc_opts_before:OK
  torvalds#241     tc_opts_both:OK
  torvalds#242     tc_opts_chain_classic:OK
  torvalds#243     tc_opts_dev_cleanup:OK
  torvalds#244     tc_opts_first:OK
  torvalds#245     tc_opts_invalid:OK
  torvalds#246     tc_opts_last:OK
  torvalds#247     tc_opts_mixed:OK
  torvalds#248     tc_opts_prepend:OK
  torvalds#249     tc_opts_replace:OK
  torvalds#250     tc_opts_revision:OK
  Summary: 14/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/prog_tests/tc_helpers.h

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Isovalent */
+#ifndef TC_HELPERS
+#define TC_HELPERS
+#include <test_progs.h>
+
+static inline __u32 id_from_prog_fd(int fd)
+{
+	struct bpf_prog_info prog_info = {};
+	__u32 prog_info_len = sizeof(prog_info);
+	int err;
+
+	err = bpf_obj_get_info_by_fd(fd, &prog_info, &prog_info_len);
+	if (!ASSERT_OK(err, "id_from_prog_fd"))
+		return 0;
+
+	ASSERT_NEQ(prog_info.id, 0, "prog_info.id");
+	return prog_info.id;
+}
+
+static inline __u32 id_from_link_fd(int fd)
+{
+	struct bpf_link_info link_info = {};
+	__u32 link_info_len = sizeof(link_info);
+	int err;
+
+	err = bpf_link_get_info_by_fd(fd, &link_info, &link_info_len);
+	if (!ASSERT_OK(err, "id_from_link_fd"))
+		return 0;
+
+	ASSERT_NEQ(link_info.id, 0, "link_info.id");
+	return link_info.id;
+}
+
+static inline __u32 ifindex_from_link_fd(int fd)
+{
+	struct bpf_link_info link_info = {};
+	__u32 link_info_len = sizeof(link_info);
+	int err;
+
+	err = bpf_link_get_info_by_fd(fd, &link_info, &link_info_len);
+	if (!ASSERT_OK(err, "id_from_link_fd"))
+		return 0;
+
+	return link_info.tcx.ifindex;
+}
+
+static inline void __assert_mprog_count(int target, int expected, bool miniq, int ifindex)
+{
+	__u32 count = 0, attach_flags = 0;
+	int err;
+
+	err = bpf_prog_query(ifindex, target, 0, &attach_flags,
+			     NULL, &count);
+	ASSERT_EQ(count, expected, "count");
+	if (!expected && !miniq)
+		ASSERT_EQ(err, -ENOENT, "prog_query");
+	else
+		ASSERT_EQ(err, 0, "prog_query");
+}
+
+static inline void assert_mprog_count(int target, int expected)
+{
+	__assert_mprog_count(target, expected, false, loopback);
+}
+
+static inline void assert_mprog_count_ifindex(int ifindex, int target, int expected)
+{
+	__assert_mprog_count(target, expected, false, ifindex);
+}
+
+#endif /* TC_HELPERS */