selftests/bpf: Add a selftest for bpf_csum_diff()

Add a selftest for the bpf_csum_diff() helper. This selftests runs the
helper in all three configurations(push, pull, and diff) and verifies
its output. The correct results have been computed by hand and by the
helper's older implementation.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20241026125339.26459-5-puranjay@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/test_csum_diff.c b/tools/testing/selftests/bpf/prog_tests/test_csum_diff.c
new file mode 100644 (file)
index 0000000..107b20d
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_csum_diff.c
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright Amazon.com Inc. or its affiliates */
+#include <test_progs.h>
+#include "csum_diff_test.skel.h"
+
+#define BUFF_SZ 512
+
+struct testcase {
+       unsigned long long to_buff[BUFF_SZ / 8];
+       unsigned int to_buff_len;
+       unsigned long long from_buff[BUFF_SZ / 8];
+       unsigned int from_buff_len;
+       unsigned short seed;
+       unsigned short result;
+};
+
+#define NUM_PUSH_TESTS 4
+
+struct testcase push_tests[NUM_PUSH_TESTS] = {
+       {
+               .to_buff = {
+                       0xdeadbeefdeadbeef,
+               },
+               .to_buff_len = 8,
+               .from_buff = {},
+               .from_buff_len = 0,
+               .seed = 0,
+               .result = 0x3b3b
+       },
+       {
+               .to_buff = {
+                       0xdeadbeefdeadbeef,
+                       0xbeefdeadbeefdead,
+               },
+               .to_buff_len = 16,
+               .from_buff = {},
+               .from_buff_len = 0,
+               .seed = 0x1234,
+               .result = 0x88aa
+       },
+       {
+               .to_buff = {
+                       0xdeadbeefdeadbeef,
+                       0xbeefdeadbeefdead,
+               },
+               .to_buff_len = 15,
+               .from_buff = {},
+               .from_buff_len = 0,
+               .seed = 0x1234,
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+               .result = 0xcaa9
+#else
+               .result = 0x87fd
+#endif
+       },
+       {
+               .to_buff = {
+                       0x327b23c66b8b4567,
+                       0x66334873643c9869,
+                       0x19495cff74b0dc51,
+                       0x625558ec2ae8944a,
+                       0x46e87ccd238e1f29,
+                       0x507ed7ab3d1b58ba,
+                       0x41b71efb2eb141f2,
+                       0x7545e14679e2a9e3,
+                       0x5bd062c2515f007c,
+                       0x4db127f812200854,
+                       0x1f16e9e80216231b,
+                       0x66ef438d1190cde7,
+                       0x3352255a140e0f76,
+                       0x0ded7263109cf92e,
+                       0x1befd79f7fdcc233,
+                       0x6b68079a41a7c4c9,
+                       0x25e45d324e6afb66,
+                       0x431bd7b7519b500d,
+                       0x7c83e4583f2dba31,
+                       0x62bbd95a257130a3,
+                       0x628c895d436c6125,
+                       0x721da317333ab105,
+                       0x2d1d5ae92443a858,
+                       0x75a2a8d46763845e,
+                       0x79838cb208edbdab,
+                       0x0b03e0c64353d0cd,
+                       0x54e49eb4189a769b,
+                       0x2ca8861171f32454,
+                       0x02901d820836c40e,
+                       0x081386413a95f874,
+                       0x7c3dbd3d1e7ff521,
+                       0x6ceaf087737b8ddc,
+                       0x4516dde922221a70,
+                       0x614fd4a13006c83e,
+                       0x5577f8e1419ac241,
+                       0x05072367440badfc,
+                       0x77465f013804823e,
+                       0x5c482a977724c67e,
+                       0x5e884adc2463b9ea,
+                       0x2d51779651ead36b,
+                       0x153ea438580bd78f,
+                       0x70a64e2a3855585c,
+                       0x2a487cb06a2342ec,
+                       0x725a06fb1d4ed43b,
+                       0x57e4ccaf2cd89a32,
+                       0x4b588f547a6d8d3c,
+                       0x6de91b18542289ec,
+                       0x7644a45c38437fdb,
+                       0x684a481a32fff902,
+                       0x749abb43579478fe,
+                       0x1ba026fa3dc240fb,
+                       0x75c6c33a79a1deaa,
+                       0x70c6a52912e685fb,
+                       0x374a3fe6520eedd1,
+                       0x23f9c13c4f4ef005,
+                       0x275ac794649bb77c,
+                       0x1cf10fd839386575,
+                       0x235ba861180115be,
+                       0x354fe9f947398c89,
+                       0x741226bb15b5af5c,
+                       0x10233c990d34b6a8,
+                       0x615740953f6ab60f,
+                       0x77ae35eb7e0c57b1,
+                       0x310c50b3579be4f1,
+               },
+               .to_buff_len = 512,
+               .from_buff = {},
+               .from_buff_len = 0,
+               .seed = 0xffff,
+               .result = 0xca45
+       },
+};
+
+#define NUM_PULL_TESTS 4
+
+struct testcase pull_tests[NUM_PULL_TESTS] = {
+       {
+               .from_buff = {
+                       0xdeadbeefdeadbeef,
+               },
+               .from_buff_len = 8,
+               .to_buff = {},
+               .to_buff_len = 0,
+               .seed = 0,
+               .result = 0xc4c4
+       },
+       {
+               .from_buff = {
+                       0xdeadbeefdeadbeef,
+                       0xbeefdeadbeefdead,
+               },
+               .from_buff_len = 16,
+               .to_buff = {},
+               .to_buff_len = 0,
+               .seed = 0x1234,
+               .result = 0x9bbd
+       },
+       {
+               .from_buff = {
+                       0xdeadbeefdeadbeef,
+                       0xbeefdeadbeefdead,
+               },
+               .from_buff_len = 15,
+               .to_buff = {},
+               .to_buff_len = 0,
+               .seed = 0x1234,
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+               .result = 0x59be
+#else
+               .result = 0x9c6a
+#endif
+       },
+       {
+               .from_buff = {
+                       0x327b23c66b8b4567,
+                       0x66334873643c9869,
+                       0x19495cff74b0dc51,
+                       0x625558ec2ae8944a,
+                       0x46e87ccd238e1f29,
+                       0x507ed7ab3d1b58ba,
+                       0x41b71efb2eb141f2,
+                       0x7545e14679e2a9e3,
+                       0x5bd062c2515f007c,
+                       0x4db127f812200854,
+                       0x1f16e9e80216231b,
+                       0x66ef438d1190cde7,
+                       0x3352255a140e0f76,
+                       0x0ded7263109cf92e,
+                       0x1befd79f7fdcc233,
+                       0x6b68079a41a7c4c9,
+                       0x25e45d324e6afb66,
+                       0x431bd7b7519b500d,
+                       0x7c83e4583f2dba31,
+                       0x62bbd95a257130a3,
+                       0x628c895d436c6125,
+                       0x721da317333ab105,
+                       0x2d1d5ae92443a858,
+                       0x75a2a8d46763845e,
+                       0x79838cb208edbdab,
+                       0x0b03e0c64353d0cd,
+                       0x54e49eb4189a769b,
+                       0x2ca8861171f32454,
+                       0x02901d820836c40e,
+                       0x081386413a95f874,
+                       0x7c3dbd3d1e7ff521,
+                       0x6ceaf087737b8ddc,
+                       0x4516dde922221a70,
+                       0x614fd4a13006c83e,
+                       0x5577f8e1419ac241,
+                       0x05072367440badfc,
+                       0x77465f013804823e,
+                       0x5c482a977724c67e,
+                       0x5e884adc2463b9ea,
+                       0x2d51779651ead36b,
+                       0x153ea438580bd78f,
+                       0x70a64e2a3855585c,
+                       0x2a487cb06a2342ec,
+                       0x725a06fb1d4ed43b,
+                       0x57e4ccaf2cd89a32,
+                       0x4b588f547a6d8d3c,
+                       0x6de91b18542289ec,
+                       0x7644a45c38437fdb,
+                       0x684a481a32fff902,
+                       0x749abb43579478fe,
+                       0x1ba026fa3dc240fb,
+                       0x75c6c33a79a1deaa,
+                       0x70c6a52912e685fb,
+                       0x374a3fe6520eedd1,
+                       0x23f9c13c4f4ef005,
+                       0x275ac794649bb77c,
+                       0x1cf10fd839386575,
+                       0x235ba861180115be,
+                       0x354fe9f947398c89,
+                       0x741226bb15b5af5c,
+                       0x10233c990d34b6a8,
+                       0x615740953f6ab60f,
+                       0x77ae35eb7e0c57b1,
+                       0x310c50b3579be4f1,
+               },
+               .from_buff_len = 512,
+               .to_buff = {},
+               .to_buff_len = 0,
+               .seed = 0xffff,
+               .result = 0x35ba
+       },
+};
+
+#define NUM_DIFF_TESTS 4
+
+struct testcase diff_tests[NUM_DIFF_TESTS] = {
+       {
+               .from_buff = {
+                       0xdeadbeefdeadbeef,
+               },
+               .from_buff_len = 8,
+               .to_buff = {
+                       0xabababababababab,
+               },
+               .to_buff_len = 8,
+               .seed = 0,
+               .result = 0x7373
+       },
+       {
+               .from_buff = {
+                       0xdeadbeefdeadbeef,
+               },
+               .from_buff_len = 7,
+               .to_buff = {
+                       0xabababababababab,
+               },
+               .to_buff_len = 7,
+               .seed = 0,
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+               .result = 0xa673
+#else
+               .result = 0x73b7
+#endif
+       },
+       {
+               .from_buff = {
+                       0,
+               },
+               .from_buff_len = 8,
+               .to_buff = {
+                       0xabababababababab,
+               },
+               .to_buff_len = 8,
+               .seed = 0,
+               .result = 0xaeae
+       },
+       {
+               .from_buff = {
+                       0xdeadbeefdeadbeef
+               },
+               .from_buff_len = 8,
+               .to_buff = {
+                       0,
+               },
+               .to_buff_len = 8,
+               .seed = 0xffff,
+               .result = 0xc4c4
+       },
+};
+
+#define NUM_EDGE_TESTS 4
+
+struct testcase edge_tests[NUM_EDGE_TESTS] = {
+       {
+               .from_buff = {},
+               .from_buff_len = 0,
+               .to_buff = {},
+               .to_buff_len = 0,
+               .seed = 0,
+               .result = 0
+       },
+       {
+               .from_buff = {
+                       0x1234
+               },
+               .from_buff_len = 0,
+               .to_buff = {
+                       0x1234
+               },
+               .to_buff_len = 0,
+               .seed = 0,
+               .result = 0
+       },
+       {
+               .from_buff = {},
+               .from_buff_len = 0,
+               .to_buff = {},
+               .to_buff_len = 0,
+               .seed = 0x1234,
+               .result = 0x1234
+       },
+       {
+               .from_buff = {},
+               .from_buff_len = 512,
+               .to_buff = {},
+               .to_buff_len = 0,
+               .seed = 0xffff,
+               .result = 0xffff
+       },
+};
+
+static unsigned short trigger_csum_diff(const struct csum_diff_test *skel)
+{
+       u8 tmp_out[64 << 2] = {};
+       u8 tmp_in[64] = {};
+       int err;
+       int pfd;
+
+       LIBBPF_OPTS(bpf_test_run_opts, topts,
+               .data_in = tmp_in,
+               .data_size_in = sizeof(tmp_in),
+               .data_out = tmp_out,
+               .data_size_out = sizeof(tmp_out),
+               .repeat = 1,
+       );
+       pfd = bpf_program__fd(skel->progs.compute_checksum);
+       err = bpf_prog_test_run_opts(pfd, &topts);
+       if (err)
+               return -1;
+
+       return skel->bss->result;
+}
+
+static void test_csum_diff(struct testcase *tests, int num_tests)
+{
+       struct csum_diff_test *skel;
+       unsigned short got;
+       int err;
+
+       for (int i = 0; i < num_tests; i++) {
+               skel = csum_diff_test__open();
+               if (!ASSERT_OK_PTR(skel, "csum_diff_test open"))
+                       return;
+
+               skel->rodata->to_buff_len = tests[i].to_buff_len;
+               skel->rodata->from_buff_len = tests[i].from_buff_len;
+
+               err = csum_diff_test__load(skel);
+               if (!ASSERT_EQ(err, 0, "csum_diff_test load"))
+                       goto out;
+
+               memcpy(skel->bss->to_buff, tests[i].to_buff, tests[i].to_buff_len);
+               memcpy(skel->bss->from_buff, tests[i].from_buff, tests[i].from_buff_len);
+               skel->bss->seed = tests[i].seed;
+
+               got = trigger_csum_diff(skel);
+               ASSERT_EQ(got, tests[i].result, "csum_diff result");
+
+               csum_diff_test__destroy(skel);
+       }
+
+       return;
+out:
+       csum_diff_test__destroy(skel);
+}
+
+void test_test_csum_diff(void)
+{
+       if (test__start_subtest("csum_diff_push"))
+               test_csum_diff(push_tests, NUM_PUSH_TESTS);
+       if (test__start_subtest("csum_diff_pull"))
+               test_csum_diff(pull_tests, NUM_PULL_TESTS);
+       if (test__start_subtest("csum_diff_diff"))
+               test_csum_diff(diff_tests, NUM_DIFF_TESTS);
+       if (test__start_subtest("csum_diff_edge"))
+               test_csum_diff(edge_tests, NUM_EDGE_TESTS);
+}

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 (file)
index 0000000..9438f17
--- /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;
+}