* [PATCH v1 net] selftests: af_unix: drain after peek and verify SO_PEEK_OFF reset
@ 2026-01-22 3:36 Soichiro Ueda
2026-01-22 21:33 ` Willem de Bruijn
0 siblings, 1 reply; 3+ messages in thread
From: Soichiro Ueda @ 2026-01-22 3:36 UTC (permalink / raw)
To: Kuniyuki Iwashima, David S. Miller, Eric Dumazet, Jakub Kicinski,
netdev
Cc: Simon Horman, Soichiro Ueda, Miao Wang
Extend the so_peek_off selftest to validate behavior after MSG_PEEK.
After exercising SO_PEEK_OFF via MSG_PEEK, drain the receive queue with a
non-peek recv() and verify that it can receive all the content in the
buffer and SO_PEEK_OFF returns back to 0.
This improvement is suggested by Miao Wang when the so_peek_off selftest
was added.
Link: https://lore.kernel.org/all/7B657CC7-B5CA-46D2-8A4B-8AB5FB83C6DA@gmail.com/
Suggested-by: Miao Wang <shankerwangmiao@gmail.com>
Signed-off-by: Soichiro Ueda <the.latticeheart@gmail.com>
---
.../selftests/net/af_unix/so_peek_off.c | 49 +++++++++++++++++++
1 file changed, 49 insertions(+)
diff --git a/tools/testing/selftests/net/af_unix/so_peek_off.c b/tools/testing/selftests/net/af_unix/so_peek_off.c
index 86e7b0fb522d..813e3b3655d3 100644
--- a/tools/testing/selftests/net/af_unix/so_peek_off.c
+++ b/tools/testing/selftests/net/af_unix/so_peek_off.c
@@ -76,6 +76,19 @@ FIXTURE_TEARDOWN(so_peek_off)
ASSERT_STREQ(str, buf); \
} while (0)
+#define peekoffeq(fd, expected) \
+ do { \
+ int off = -1; \
+ socklen_t optlen = sizeof(off); \
+ int ret; \
+ \
+ ret = getsockopt(fd, SOL_SOCKET, SO_PEEK_OFF, \
+ &off, &optlen); \
+ ASSERT_EQ(0, ret); \
+ ASSERT_EQ((socklen_t)sizeof(off), optlen); \
+ ASSERT_EQ(expected, off); \
+ } while (0)
+
#define async \
for (pid_t pid = (pid = fork(), \
pid < 0 ? \
@@ -92,6 +105,14 @@ TEST_F(so_peek_off, single_chunk)
recveq(self->fd[1], "aaaa", 4, MSG_PEEK);
recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
+
+ if (variant->type == SOCK_STREAM) {
+ recveq(self->fd[1], "aaaa", 4, 0);
+ recveq(self->fd[1], "bbbb", 100, 0);
+ } else {
+ recveq(self->fd[1], "aaaabbbb", 100, 0);
+ }
+ peekoffeq(self->fd[1], 0);
}
TEST_F(so_peek_off, two_chunks)
@@ -101,6 +122,13 @@ TEST_F(so_peek_off, two_chunks)
recveq(self->fd[1], "aaaa", 4, MSG_PEEK);
recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
+
+ if (variant->type == SOCK_STREAM)
+ recveq(self->fd[1], "aaaa", 4, 0);
+ else
+ recveq(self->fd[1], "aaaa", 100, 0);
+ recveq(self->fd[1], "bbbb", 100, 0);
+ peekoffeq(self->fd[1], 0);
}
TEST_F(so_peek_off, two_chunks_blocking)
@@ -119,6 +147,13 @@ TEST_F(so_peek_off, two_chunks_blocking)
/* goto again; -> goto redo; in unix_stream_read_generic(). */
recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
+
+ if (variant->type == SOCK_STREAM)
+ recveq(self->fd[1], "aaaa", 4, 0);
+ else
+ recveq(self->fd[1], "aaaa", 100, 0);
+ recveq(self->fd[1], "bbbb", 100, 0);
+ peekoffeq(self->fd[1], 0);
}
TEST_F(so_peek_off, two_chunks_overlap)
@@ -137,6 +172,13 @@ TEST_F(so_peek_off, two_chunks_overlap)
recveq(self->fd[1], "aa", 100, MSG_PEEK);
recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
}
+
+ if (variant->type == SOCK_STREAM)
+ recveq(self->fd[1], "aaaa", 4, 0);
+ else
+ recveq(self->fd[1], "aaaa", 100, 0);
+ recveq(self->fd[1], "bbbb", 100, 0);
+ peekoffeq(self->fd[1], 0);
}
TEST_F(so_peek_off, two_chunks_overlap_blocking)
@@ -157,6 +199,13 @@ TEST_F(so_peek_off, two_chunks_overlap_blocking)
recveq(self->fd[1], "aa", 100, MSG_PEEK);
recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
+
+ if (variant->type == SOCK_STREAM)
+ recveq(self->fd[1], "aaaa", 4, 0);
+ else
+ recveq(self->fd[1], "aaaa", 100, 0);
+ recveq(self->fd[1], "bbbb", 100, 0);
+ peekoffeq(self->fd[1], 0);
}
TEST_HARNESS_MAIN
--
2.52.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v1 net] selftests: af_unix: drain after peek and verify SO_PEEK_OFF reset
2026-01-22 3:36 [PATCH v1 net] selftests: af_unix: drain after peek and verify SO_PEEK_OFF reset Soichiro Ueda
@ 2026-01-22 21:33 ` Willem de Bruijn
2026-02-12 22:49 ` Soichiro Ueda
0 siblings, 1 reply; 3+ messages in thread
From: Willem de Bruijn @ 2026-01-22 21:33 UTC (permalink / raw)
To: Soichiro Ueda, Kuniyuki Iwashima, David S. Miller, Eric Dumazet,
Jakub Kicinski, netdev
Cc: Simon Horman, Soichiro Ueda, Miao Wang
Soichiro Ueda wrote:
> Extend the so_peek_off selftest to validate behavior after MSG_PEEK.
>
> After exercising SO_PEEK_OFF via MSG_PEEK, drain the receive queue with a
> non-peek recv() and verify that it can receive all the content in the
> buffer and SO_PEEK_OFF returns back to 0.
>
> This improvement is suggested by Miao Wang when the so_peek_off selftest
> was added.
>
> Link: https://lore.kernel.org/all/7B657CC7-B5CA-46D2-8A4B-8AB5FB83C6DA@gmail.com/
> Suggested-by: Miao Wang <shankerwangmiao@gmail.com>
> Signed-off-by: Soichiro Ueda <the.latticeheart@gmail.com>
> ---
> .../selftests/net/af_unix/so_peek_off.c | 49 +++++++++++++++++++
> 1 file changed, 49 insertions(+)
>
> diff --git a/tools/testing/selftests/net/af_unix/so_peek_off.c b/tools/testing/selftests/net/af_unix/so_peek_off.c
> index 86e7b0fb522d..813e3b3655d3 100644
> --- a/tools/testing/selftests/net/af_unix/so_peek_off.c
> +++ b/tools/testing/selftests/net/af_unix/so_peek_off.c
> @@ -76,6 +76,19 @@ FIXTURE_TEARDOWN(so_peek_off)
> ASSERT_STREQ(str, buf); \
> } while (0)
>
> +#define peekoffeq(fd, expected) \
> + do { \
> + int off = -1; \
> + socklen_t optlen = sizeof(off); \
> + int ret; \
> + \
> + ret = getsockopt(fd, SOL_SOCKET, SO_PEEK_OFF, \
> + &off, &optlen); \
> + ASSERT_EQ(0, ret); \
> + ASSERT_EQ((socklen_t)sizeof(off), optlen); \
> + ASSERT_EQ(expected, off); \
> + } while (0)
> +
> #define async \
> for (pid_t pid = (pid = fork(), \
> pid < 0 ? \
> @@ -92,6 +105,14 @@ TEST_F(so_peek_off, single_chunk)
>
> recveq(self->fd[1], "aaaa", 4, MSG_PEEK);
> recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
> +
> + if (variant->type == SOCK_STREAM) {
> + recveq(self->fd[1], "aaaa", 4, 0);
> + recveq(self->fd[1], "bbbb", 100, 0);
> + } else {
> + recveq(self->fd[1], "aaaabbbb", 100, 0);
> + }
> + peekoffeq(self->fd[1], 0);
Do you want to test peekoffeq before the non-peek read too?
> }
>
> TEST_F(so_peek_off, two_chunks)
> @@ -101,6 +122,13 @@ TEST_F(so_peek_off, two_chunks)
>
> recveq(self->fd[1], "aaaa", 4, MSG_PEEK);
> recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
> +
> + if (variant->type == SOCK_STREAM)
> + recveq(self->fd[1], "aaaa", 4, 0);
> + else
> + recveq(self->fd[1], "aaaa", 100, 0);
Why this difference in length?
Because stream read will block if > 4, while datagram does not?
If so, can perhaps use 4 for both or explicitly use non-blocking read.
> + recveq(self->fd[1], "bbbb", 100, 0);
> + peekoffeq(self->fd[1], 0);
> }
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v1 net] selftests: af_unix: drain after peek and verify SO_PEEK_OFF reset
2026-01-22 21:33 ` Willem de Bruijn
@ 2026-02-12 22:49 ` Soichiro Ueda
0 siblings, 0 replies; 3+ messages in thread
From: Soichiro Ueda @ 2026-02-12 22:49 UTC (permalink / raw)
To: Willem de Bruijn
Cc: Kuniyuki Iwashima, David S. Miller, Eric Dumazet, Jakub Kicinski,
netdev, Simon Horman, Miao Wang
Hi Willem,
Thank you for your review and helpful comments.
> Soichiro Ueda wrote:
> > Extend the so_peek_off selftest to validate behavior after MSG_PEEK.
> >
> > After exercising SO_PEEK_OFF via MSG_PEEK, drain the receive queue with a
> > non-peek recv() and verify that it can receive all the content in the
> > buffer and SO_PEEK_OFF returns back to 0.
> >
> > This improvement is suggested by Miao Wang when the so_peek_off selftest
> > was added.
> >
> > Link: https://lore.kernel.org/all/7B657CC7-B5CA-46D2-8A4B-8AB5FB83C6DA@gmail.com/
> > Suggested-by: Miao Wang <shankerwangmiao@gmail.com>
> > Signed-off-by: Soichiro Ueda <the.latticeheart@gmail.com>
> > ---
> > .../selftests/net/af_unix/so_peek_off.c | 49 +++++++++++++++++++
> > 1 file changed, 49 insertions(+)
> >
> > diff --git a/tools/testing/selftests/net/af_unix/so_peek_off.c b/tools/testing/selftests/net/af_unix/so_peek_off.c
> > index 86e7b0fb522d..813e3b3655d3 100644
> > --- a/tools/testing/selftests/net/af_unix/so_peek_off.c
> > +++ b/tools/testing/selftests/net/af_unix/so_peek_off.c
> > @@ -76,6 +76,19 @@ FIXTURE_TEARDOWN(so_peek_off)
> > ASSERT_STREQ(str, buf); \
> > } while (0)
> >
> > +#define peekoffeq(fd, expected) \
> > + do { \
> > + int off = -1; \
> > + socklen_t optlen = sizeof(off); \
> > + int ret; \
> > + \
> > + ret = getsockopt(fd, SOL_SOCKET, SO_PEEK_OFF, \
> > + &off, &optlen); \
> > + ASSERT_EQ(0, ret); \
> > + ASSERT_EQ((socklen_t)sizeof(off), optlen); \
> > + ASSERT_EQ(expected, off); \
> > + } while (0)
> > +
> > #define async \
> > for (pid_t pid = (pid = fork(), \
> > pid < 0 ? \
> > @@ -92,6 +105,14 @@ TEST_F(so_peek_off, single_chunk)
> >
> > recveq(self->fd[1], "aaaa", 4, MSG_PEEK);
> > recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
> > +
> > + if (variant->type == SOCK_STREAM) {
> > + recveq(self->fd[1], "aaaa", 4, 0);
> > + recveq(self->fd[1], "bbbb", 100, 0);
> > + } else {
> > + recveq(self->fd[1], "aaaabbbb", 100, 0);
> > + }
> > + peekoffeq(self->fd[1], 0);
>
> Do you want to test peekoffeq before the non-peek read too?
>
That is a great point. I should verify that the offset has correctly
advanced before it gets reset to 0 by the non-peek read. I will add
this check in v2.
> > }
> >
> > TEST_F(so_peek_off, two_chunks)
> > @@ -101,6 +122,13 @@ TEST_F(so_peek_off, two_chunks)
> >
> > recveq(self->fd[1], "aaaa", 4, MSG_PEEK);
> > recveq(self->fd[1], "bbbb", 100, MSG_PEEK);
> > +
> > + if (variant->type == SOCK_STREAM)
> > + recveq(self->fd[1], "aaaa", 4, 0);
> > + else
> > + recveq(self->fd[1], "aaaa", 100, 0);
>
> Why this difference in length?
>
> Because stream read will block if > 4, while datagram does not?
>
> If so, can perhaps use 4 for both or explicitly use non-blocking read.
>
> > + recveq(self->fd[1], "bbbb", 100, 0);
> > + peekoffeq(self->fd[1], 0);
> > }
For SOCK_DGRAM, I used 100 simply to ensure the entire first packet
was consumed. But using 4 for both is cleaner and consistent. I will
unify the length to 4 in the next version.
I will send v2 shortly with these changes.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-01-22 3:36 [PATCH v1 net] selftests: af_unix: drain after peek and verify SO_PEEK_OFF reset Soichiro Ueda
2026-01-22 21:33 ` Willem de Bruijn
2026-02-12 22:49 ` Soichiro Ueda
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