[PATCH bpf-next 1/5] selftests/bpf: sockmap_redir: Simplify try_recv()

Michal Luczaj
2025-09-05T11:12:10Z

try_recv() was meant to support both @expect_success cases, but all the
callers use @expect_success=false anyway. Drop the unused logic and fold in
MSG_DONTWAIT. Adapt callers.

Subtle change here: recv() return value of 0 will also be considered (an
unexpected) success.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
.../selftests/bpf/prog_tests/sockmap_redir.c | 25 +++++++++-------------
1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c b/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c
index 9c461d93113db20de65ac353f92dfdbe32ffbd3b..c1bf1076e8152b7d83c3e07e2dce746b5a39cf7e 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c
@@ -144,17 +144,14 @@ static void get_redir_params(struct redir_spec *redir,
*redirect_flags = 0;
}

-static void try_recv(const char *prefix, int fd, int flags, bool expect_success)
+static void fail_recv(const char *prefix, int fd, int more_flags)
{
ssize_t n;
char buf;

- errno = 0;
- n = recv(fd, &buf, 1, flags);
- if (n < 0 && expect_success)
- FAIL_ERRNO("%s: unexpected failure: retval=%zd", prefix, n);
- if (!n && !expect_success)
- FAIL("%s: expected failure: retval=%zd", prefix, n);
+ n = recv(fd, &buf, 1, MSG_DONTWAIT | more_flags);
+ if (n >= 0)
+ FAIL("%s: unexpected success: retval=%zd", prefix, n);
}

static void handle_unsupported(int sd_send, int sd_peer, int sd_in, int sd_out,
@@ -188,13 +185,13 @@ static void handle_unsupported(int sd_send, int sd_peer, int sd_in, int sd_out,
}

/* Ensure queues are empty */
- try_recv("bpf.recv(sd_send)", sd_send, MSG_DONTWAIT, false);
+ fail_recv("bpf.recv(sd_send)", sd_send, 0);
if (sd_in != sd_send)
- try_recv("bpf.recv(sd_in)", sd_in, MSG_DONTWAIT, false);
+ fail_recv("bpf.recv(sd_in)", sd_in, 0);

- try_recv("bpf.recv(sd_out)", sd_out, MSG_DONTWAIT, false);
+ fail_recv("bpf.recv(sd_out)", sd_out, 0);
if (sd_recv != sd_out)
- try_recv("bpf.recv(sd_recv)", sd_recv, MSG_DONTWAIT, false);
+ fail_recv("bpf.recv(sd_recv)", sd_recv, 0);
}

static void test_send_redir_recv(int sd_send, int send_flags, int sd_peer,
@@ -257,15 +254,13 @@ static void test_send_redir_recv(int sd_send, int send_flags, int sd_peer,

if (send_flags & MSG_OOB) {
/* Fail reading OOB while in sockmap */
- try_recv("bpf.recv(sd_out, MSG_OOB)", sd_out,
- MSG_OOB | MSG_DONTWAIT, false);
+ fail_recv("bpf.recv(sd_out, MSG_OOB)", sd_out, MSG_OOB);

/* Remove sd_out from sockmap */
xbpf_map_delete_elem(maps->out, &u32(0));

/* Check that OOB was dropped on redirect */
- try_recv("recv(sd_out, MSG_OOB)", sd_out,
- MSG_OOB | MSG_DONTWAIT, false);
+ fail_recv("recv(sd_out, MSG_OOB)", sd_out, MSG_OOB);

goto del_in;
}

--
2.50.1