1 files changed, 42 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/csum_diff_test.c b/tools/testing/selftests/bpf/progs/csum_diff_test.c
new file mode 100644
index 000000000000..9438f1773a58
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/csum_diff_test.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright Amazon.com Inc. or its affiliates */
+#include <linux/types.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#define BUFF_SZ 512
+
+/* Will be updated by benchmark before program loading */
+char to_buff[BUFF_SZ];
+const volatile unsigned int to_buff_len = 0;
+char from_buff[BUFF_SZ];
+const volatile unsigned int from_buff_len = 0;
+unsigned short seed = 0;
+
+short result;
+
+char _license[] SEC("license") = "GPL";
+
+SEC("tc")
+int compute_checksum(void *ctx)
+{
+	int to_len_half = to_buff_len / 2;
+	int from_len_half = from_buff_len / 2;
+	short result2;
+
+	/* Calculate checksum in one go */
+	result2 = bpf_csum_diff((void *)from_buff, from_buff_len,
+				(void *)to_buff, to_buff_len, seed);
+
+	/* Calculate checksum by concatenating bpf_csum_diff()*/
+	result = bpf_csum_diff((void *)from_buff, from_buff_len - from_len_half,
+			       (void *)to_buff, to_buff_len - to_len_half, seed);
+
+	result = bpf_csum_diff((void *)from_buff + (from_buff_len - from_len_half), from_len_half,
+			       (void *)to_buff + (to_buff_len - to_len_half), to_len_half, result);
+
+	result = (result == result2) ? result : 0;
+
+	return 0;
+}