[PATCH bpf-next v3 1/8] selftests/bpf: Fix sk_assign on s390x

Ilya Leoshkevich
2023-01-29T19:05:37Z

sk_assign is failing on an s390x machine running Debian "bookworm" for
2 reasons: legacy server_map definition and uninitialized addrlen in
recvfrom() call.

Fix by adding a new-style server_map definition and dropping addrlen
(recvfrom() allows NULL values for src_addr and addrlen).

Since the test should support tc built without libbpf, build the prog
twice: with the old-style definition and with the new-style definition,
then select the right one at runtime. This could be done at compile
time too, but this would not be cross-compilation friendly.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
.../selftests/bpf/prog_tests/sk_assign.c | 25 ++++++++++++++-----
.../selftests/bpf/progs/test_sk_assign.c | 11 ++++++++
.../bpf/progs/test_sk_assign_libbpf.c | 3 +++
3 files changed, 33 insertions(+), 6 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/test_sk_assign_libbpf.c

diff --git a/tools/testing/selftests/bpf/prog_tests/sk_assign.c b/tools/testing/selftests/bpf/prog_tests/sk_assign.c
index 3e190ed63976..1374b626a985 100644
--- a/tools/testing/selftests/bpf/prog_tests/sk_assign.c
+++ b/tools/testing/selftests/bpf/prog_tests/sk_assign.c
@@ -29,7 +29,23 @@ static int stop, duration;
static bool
configure_stack(void)
{
+ char tc_version[128];
char tc_cmd[BUFSIZ];
+ char *prog;
+ FILE *tc;
+
+ /* Check whether tc is built with libbpf. */
+ tc = popen("tc -V", "r");
+ if (CHECK_FAIL(!tc))
+ return false;
+ if (CHECK_FAIL(!fgets(tc_version, sizeof(tc_version), tc)))
+ return false;
+ if (strstr(tc_version, ", libbpf "))
+ prog = "test_sk_assign_libbpf.bpf.o";
+ else
+ prog = "test_sk_assign.bpf.o";
+ if (CHECK_FAIL(pclose(tc)))
+ return false;

/* Move to a new networking namespace */
if (CHECK_FAIL(unshare(CLONE_NEWNET)))
@@ -46,8 +62,8 @@ configure_stack(void)
/* Load qdisc, BPF program */
if (CHECK_FAIL(system("tc qdisc add dev lo clsact")))
return false;
- sprintf(tc_cmd, "%s %s %s %s", "tc filter add dev lo ingress bpf",
- "direct-action object-file ./test_sk_assign.bpf.o",
+ sprintf(tc_cmd, "%s %s %s %s %s", "tc filter add dev lo ingress bpf",
+ "direct-action object-file", prog,
"section tc",
(env.verbosity < VERBOSE_VERY) ? " 2>/dev/null" : "verbose");
if (CHECK(system(tc_cmd), "BPF load failed;",
@@ -129,15 +145,12 @@ get_port(int fd)
static ssize_t
rcv_msg(int srv_client, int type)
{
- struct sockaddr_storage ss;
char buf[BUFSIZ];
- socklen_t slen;

if (type == SOCK_STREAM)
return read(srv_client, &buf, sizeof(buf));
else
- return recvfrom(srv_client, &buf, sizeof(buf), 0,
- (struct sockaddr *)&ss, &slen);
+ return recvfrom(srv_client, &buf, sizeof(buf), 0, NULL, NULL);
}

static int
diff --git a/tools/testing/selftests/bpf/progs/test_sk_assign.c b/tools/testing/selftests/bpf/progs/test_sk_assign.c
index 98c6493d9b91..21b19b758c4e 100644
--- a/tools/testing/selftests/bpf/progs/test_sk_assign.c
+++ b/tools/testing/selftests/bpf/progs/test_sk_assign.c
@@ -16,6 +16,16 @@
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>

+#if defined(IPROUTE2_HAVE_LIBBPF)
+/* Use a new-style map definition. */
+struct {
+ __uint(type, BPF_MAP_TYPE_SOCKMAP);
+ __type(key, int);
+ __type(value, __u64);
+ __uint(pinning, LIBBPF_PIN_BY_NAME);
+ __uint(max_entries, 1);
+} server_map SEC(".maps");
+#else
/* Pin map under /sys/fs/bpf/tc/globals/ */
#define PIN_GLOBAL_NS 2

@@ -35,6 +45,7 @@ struct {
.max_elem = 1,
.pinning = PIN_GLOBAL_NS,
};
+#endif

char _license[] SEC("license") = "GPL";

diff --git a/tools/testing/selftests/bpf/progs/test_sk_assign_libbpf.c b/tools/testing/selftests/bpf/progs/test_sk_assign_libbpf.c
new file mode 100644
index 000000000000..dcf46adfda04
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_sk_assign_libbpf.c
@@ -0,0 +1,3 @@
+// SPDX-License-Identifier: GPL-2.0
+#define IPROUTE2_HAVE_LIBBPF
+#include "test_sk_assign.c"
--
2.39.1