[bpf-next PATCH v3 5/5] bpf: selftests, test probe_* helpers from SCHED_CLS

[John Fastabend <john.fastabend@gmail.com>]

Lets test using probe* in SCHED_CLS network programs as well just
to be sure these keep working. Its cheap to add the extra test
and provides a second context to test outside of sk_msg after
we generalized probe* helpers to all networking types.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
 .../testing/selftests/bpf/prog_tests/skb_helpers.c |   30 ++++++++++++++++++
 .../testing/selftests/bpf/progs/test_skb_helpers.c |   33 ++++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/skb_helpers.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_skb_helpers.c

diff --git a/tools/testing/selftests/bpf/prog_tests/skb_helpers.c b/tools/testing/selftests/bpf/prog_tests/skb_helpers.c
new file mode 100644
index 0000000..5a865c4
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/skb_helpers.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <network_helpers.h>
+
+void test_skb_helpers(void)
+{
+	struct __sk_buff skb = {
+		.wire_len = 100,
+		.gso_segs = 8,
+		.gso_size = 10,
+	};
+	struct bpf_prog_test_run_attr tattr = {
+		.data_in = &pkt_v4,
+		.data_size_in = sizeof(pkt_v4),
+		.ctx_in = &skb,
+		.ctx_size_in = sizeof(skb),
+		.ctx_out = &skb,
+		.ctx_size_out = sizeof(skb),
+	};
+	struct bpf_object *obj;
+	int err;
+
+	err = bpf_prog_load("./test_skb_helpers.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
+			    &tattr.prog_fd);
+	if (CHECK_ATTR(err, "load", "err %d errno %d\n", err, errno))
+		return;
+
+	err = bpf_prog_test_run_xattr(&tattr);
+	CHECK_ATTR(err != 0, "len", "err %d errno %d\n", err, errno);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_skb_helpers.c b/tools/testing/selftests/bpf/progs/test_skb_helpers.c
new file mode 100644
index 0000000..05a1260
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_skb_helpers.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+int _version SEC("version") = 1;
+
+#define TEST_COMM_LEN 10
+
+struct bpf_map_def SEC("maps") cgroup_map = {
+	.type			= BPF_MAP_TYPE_CGROUP_ARRAY,
+	.key_size		= sizeof(u32),
+	.value_size		= sizeof(u32),
+	.max_entries	= 1,
+};
+
+char _license[] SEC("license") = "GPL";
+
+SEC("classifier/test_skb_helpers")
+int test_skb_helpers(struct __sk_buff *skb)
+{
+	struct task_struct *task;
+	char *comm[TEST_COMM_LEN];
+	__u32 tpid;
+	int ctask;
+
+	ctask = bpf_current_task_under_cgroup(&cgroup_map, 0);
+	task = (struct task_struct *)bpf_get_current_task();
+
+	bpf_probe_read_kernel(&tpid , sizeof(tpid), &task->tgid);
+	bpf_probe_read_kernel_str(&comm, sizeof(comm), &task->comm);
+	return 0;
+}