[PATCH net-next v5 17/21] lib/bitmap: add tests for IP tunnel flags conversion helpers

Alexander Lobakin
2024-02-01T12:25:01Z

Now that there are helpers for converting IP tunnel flags between the
old __be16 format and the bitmap format, make sure they work as expected
by adding a couple of tests to the bitmap testing suite. The helpers are
all inline, so no dependencies on the related CONFIG_* (or a standalone
module) are needed.

Cover three possible cases:

1. No bits past BIT(15) are set, VTI/SIT bits are not set. This
conversion is almost a direct assignment.
2. No bits past BIT(15) are set, but VTI/SIT bit is set. During the
conversion, it must be transformed into BIT(16) in the bitmap,
but still compatible with the __be16 format.
3. The bitmap has bits past BIT(15) set (not the VTI/SIT one). The
result will be truncated.
Note that currently __IP_TUNNEL_FLAG_NUM is 17 (incl. special),
which means that the result of this case is currently
semi-false-positive. When BIT(17) is finally here, it will be
adjusted accordingly.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
lib/test_bitmap.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 105 insertions(+)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 4ee1f8ceb51d..270afc0cba5c 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -14,6 +14,8 @@
#include <linux/string.h>
#include <linux/uaccess.h>

+#include <net/ip_tunnels.h>
+
#include "../tools/testing/selftests/kselftest_module.h"

#define EXP1_IN_BITS (sizeof(exp1) * 8)
@@ -1409,6 +1411,108 @@ static void __init test_bitmap_write_perf(void)

#undef TEST_BIT_LEN

+struct ip_tunnel_flags_test {
+ const u16 *src_bits;
+ const u16 *exp_bits;
+ u8 src_num;
+ u8 exp_num;
+ __be16 exp_val;
+ bool exp_comp:1;
+};
+
+#define IP_TUNNEL_FLAGS_TEST(src, comp, eval, exp) { \
+ .src_bits = (src), \
+ .src_num = ARRAY_SIZE(src), \
+ .exp_comp = (comp), \
+ .exp_val = (eval), \
+ .exp_bits = (exp), \
+ .exp_num = ARRAY_SIZE(exp), \
+}
+
+/* These are __be16-compatible and can be compared as is */
+static const u16 ip_tunnel_flags_1[] __initconst = {
+ IP_TUNNEL_KEY_BIT,
+ IP_TUNNEL_STRICT_BIT,
+ IP_TUNNEL_ERSPAN_OPT_BIT,
+};
+
+/*
+ * Due to the previous flags design limitation, setting either
+ * ``IP_TUNNEL_CSUM_BIT`` (on Big Endian) or ``IP_TUNNEL_DONT_FRAGMENT_BIT``
+ * (on Little) also sets VTI/ISATAP bit. In the bitmap implementation, they
+ * correspond to ``BIT(16)``, which is bigger than ``U16_MAX``, but still is
+ * backward-compatible.
+ */
+#ifdef __BIG_ENDIAN
+#define IP_TUNNEL_CONFLICT_BIT IP_TUNNEL_CSUM_BIT
+#else
+#define IP_TUNNEL_CONFLICT_BIT IP_TUNNEL_DONT_FRAGMENT_BIT
+#endif
+
+static const u16 ip_tunnel_flags_2_src[] __initconst = {
+ IP_TUNNEL_CONFLICT_BIT,
+};
+
+static const u16 ip_tunnel_flags_2_exp[] __initconst = {
+ IP_TUNNEL_CONFLICT_BIT,
+ IP_TUNNEL_SIT_ISATAP_BIT,
+};
+
+/* Bits 17 and higher are not compatible with __be16 flags */
+static const u16 ip_tunnel_flags_3_src[] __initconst = {
+ IP_TUNNEL_VXLAN_OPT_BIT,
+ 17,
+ 18,
+ 20,
+};
+
+static const u16 ip_tunnel_flags_3_exp[] __initconst = {
+ IP_TUNNEL_VXLAN_OPT_BIT,
+};
+
+static const struct ip_tunnel_flags_test ip_tunnel_flags_test[] __initconst = {
+ IP_TUNNEL_FLAGS_TEST(ip_tunnel_flags_1, true,
+ cpu_to_be16(BIT(IP_TUNNEL_KEY_BIT) |
+ BIT(IP_TUNNEL_STRICT_BIT) |
+ BIT(IP_TUNNEL_ERSPAN_OPT_BIT)),
+ ip_tunnel_flags_1),
+ IP_TUNNEL_FLAGS_TEST(ip_tunnel_flags_2_src, true, VTI_ISVTI,
+ ip_tunnel_flags_2_exp),
+ IP_TUNNEL_FLAGS_TEST(ip_tunnel_flags_3_src,
+ /*
+ * This must be set to ``false`` once
+ * ``__IP_TUNNEL_FLAG_NUM`` goes above 17.
+ */
+ true,
+ cpu_to_be16(BIT(IP_TUNNEL_VXLAN_OPT_BIT)),
+ ip_tunnel_flags_3_exp),
+};
+
+static void __init test_ip_tunnel_flags(void)
+{
+ for (u32 i = 0; i < ARRAY_SIZE(ip_tunnel_flags_test); i++) {
+ typeof(*ip_tunnel_flags_test) *test = &ip_tunnel_flags_test[i];
+ IP_TUNNEL_DECLARE_FLAGS(src) = { };
+ IP_TUNNEL_DECLARE_FLAGS(exp) = { };
+ IP_TUNNEL_DECLARE_FLAGS(out);
+
+ for (u32 j = 0; j < test->src_num; j++)
+ __set_bit(test->src_bits[j], src);
+
+ for (u32 j = 0; j < test->exp_num; j++)
+ __set_bit(test->exp_bits[j], exp);
+
+ ip_tunnel_flags_from_be16(out, test->exp_val);
+
+ expect_eq_uint(test->exp_comp,
+ ip_tunnel_flags_is_be16_compat(src));
+ expect_eq_uint((__force u16)test->exp_val,
+ (__force u16)ip_tunnel_flags_to_be16(src));
+
+ __ipt_flag_op(expect_eq_bitmap, exp, out);
+ }
+}
+
static void __init selftest(void)
{
test_zero_clear();
@@ -1428,6 +1532,7 @@ static void __init selftest(void)
test_bitmap_read_write();
test_bitmap_read_perf();
test_bitmap_write_perf();
+ test_ip_tunnel_flags();

test_find_nth_bit();
test_for_each_set_bit();
--
2.43.0