[v1] Squash to "selftests/bpf: Add mptcp subflow subtest"

[PATCH mptcp-next] Squash to "selftests/bpf: Add mptcp subflow subtest"

Posted by Geliang Tang 8 months, 1 week ago

From: Geliang Tang <tanggeliang@kylinos.cn>

Add pm_nl_ctl.
Use SYS_NOFAIL in _ss_search().

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 tools/testing/selftests/bpf/Makefile           |  2 +-
 tools/testing/selftests/bpf/pm_nl_ctl.c        |  1 +
 tools/testing/selftests/bpf/prog_tests/mptcp.c | 15 ++++-----------
 3 files changed, 6 insertions(+), 12 deletions(-)
 create mode 120000 tools/testing/selftests/bpf/pm_nl_ctl.c

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index b90c718218ae..bd2e3b138a5c 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -131,7 +131,7 @@ TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
 	flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
 	test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \
 	xskxceiver xdp_redirect_multi xdp_synproxy veristat xdp_hw_metadata \
-	xdp_features bpf_test_no_cfi.ko
+	xdp_features bpf_test_no_cfi.ko pm_nl_ctl
 
 TEST_GEN_FILES += liburandom_read.so urandom_read sign-file uprobe_multi
 
diff --git a/tools/testing/selftests/bpf/pm_nl_ctl.c b/tools/testing/selftests/bpf/pm_nl_ctl.c
new file mode 120000
index 000000000000..5a08c255b278
--- /dev/null
+++ b/tools/testing/selftests/bpf/pm_nl_ctl.c
@@ -0,0 +1 @@
+../net/mptcp/pm_nl_ctl.c
\ No newline at end of file
diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index 793b4b9c2bd2..9c6d1e4f6f35 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -362,7 +362,8 @@ static int endpoint_init(char *flags)
 	SYS(fail, "ip -net %s link set dev veth1 up", NS_TEST);
 	SYS(fail, "ip -net %s addr add %s/24 dev veth2", NS_TEST, ADDR_2);
 	SYS(fail, "ip -net %s link set dev veth2 up", NS_TEST);
-	SYS(fail, "ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags);
+	if (SYS_NOFAIL("ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags))
+		SYS(fail, "ip netns exec %s ./pm_nl_ctl add %s flags %s", NS_TEST, ADDR_2, flags);
 
 	return 0;
 fail:
@@ -371,16 +372,8 @@ static int endpoint_init(char *flags)
 
 static int _ss_search(char *src, char *dst, char *port, char *keyword)
 {
-	char cmd[128];
-	int n;
-
-	n = snprintf(cmd, sizeof(cmd),
-		     "ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
-		     NS_TEST, src, dst, port, PORT_1, keyword);
-	if (n < 0 || n >= sizeof(cmd))
-		return -1;
-
-	return system(cmd);
+	return SYS_NOFAIL("ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
+			  NS_TEST, src, dst, port, PORT_1, keyword);
 }
 
 static int ss_search(char *src, char *keyword)
-- 
2.43.0

Re: [PATCH mptcp-next] Squash to "selftests/bpf: Add mptcp subflow subtest"

Posted by Matthieu Baerts 8 months, 1 week ago

Hi Geliang,

Thank you for this fix!

11 May 2024 12:42:08 Geliang Tang <geliang@kernel.org>:

> From: Geliang Tang <tanggeliang@kylinos.cn>
>
> Add pm_nl_ctl.
> Use SYS_NOFAIL in _ss_search().
>
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
> tools/testing/selftests/bpf/Makefile           |  2 +-
> tools/testing/selftests/bpf/pm_nl_ctl.c        |  1 +
> tools/testing/selftests/bpf/prog_tests/mptcp.c | 15 ++++-----------
> 3 files changed, 6 insertions(+), 12 deletions(-)
> create mode 120000 tools/testing/selftests/bpf/pm_nl_ctl.c
>
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index b90c718218ae..bd2e3b138a5c 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -131,7 +131,7 @@ TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
>     flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
>     test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \
>     xskxceiver xdp_redirect_multi xdp_synproxy veristat xdp_hw_metadata \
> -   xdp_features bpf_test_no_cfi.ko
> +   xdp_features bpf_test_no_cfi.ko pm_nl_ctl
>
> TEST_GEN_FILES += liburandom_read.so urandom_read sign-file uprobe_multi
>
> diff --git a/tools/testing/selftests/bpf/pm_nl_ctl.c b/tools/testing/selftests/bpf/pm_nl_ctl.c
> new file mode 120000
> index 000000000000..5a08c255b278
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/pm_nl_ctl.c

Best to prefix it with "mptcp_": clearer and it will be linked to MPTCP in the maintainers file.

> @@ -0,0 +1 @@
> +../net/mptcp/pm_nl_ctl.c
> \ No newline at end of file
> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> index 793b4b9c2bd2..9c6d1e4f6f35 100644
> --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> @@ -362,7 +362,8 @@ static int endpoint_init(char *flags)
>     SYS(fail, "ip -net %s link set dev veth1 up", NS_TEST);
>     SYS(fail, "ip -net %s addr add %s/24 dev veth2", NS_TEST, ADDR_2);
>     SYS(fail, "ip -net %s link set dev veth2 up", NS_TEST);
> -   SYS(fail, "ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags);
> +   if (SYS_NOFAIL("ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags))

It is maybe better to only use mptcp_pm_nl_ctl here: to maintain one way here, our CI will do the same as what the BPF one will do, and we avoid errors printed in stderr if "ip mptcp" is not supported.

> +       SYS(fail, "ip netns exec %s ./pm_nl_ctl add %s flags %s", NS_TEST, ADDR_2, flags);
>
>     return 0;
> fail:
> @@ -371,16 +372,8 @@ static int endpoint_init(char *flags)
>
> static int _ss_search(char *src, char *dst, char *port, char *keyword)
> {
> -   char cmd[128];
> -   int n;
> -
> -   n = snprintf(cmd, sizeof(cmd),
> -            "ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
> -            NS_TEST, src, dst, port, PORT_1, keyword);
> -   if (n < 0 || n >= sizeof(cmd))
> -       return -1;
> -
> -   return system(cmd);
> +   return SYS_NOFAIL("ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
> +             NS_TEST, src, dst, port, PORT_1, keyword);

If "ip mptcp" is not supported, I guess "ss -M" will not be supported as well, no?

Do we need -M here for these tests?

Cheers,
Matt

> }
>
> static int ss_search(char *src, char *keyword)
> --
> 2.43.0

Re: [PATCH mptcp-next] Squash to "selftests/bpf: Add mptcp subflow subtest"

Posted by Geliang Tang 8 months, 1 week ago

On Sat, May 11, 2024 at 03:50:29PM +0200, Matthieu Baerts wrote:
> Hi Geliang,
> 
> Thank you for this fix!
> 
> 11 May 2024 12:42:08 Geliang Tang <geliang@kernel.org>:
> 
> > From: Geliang Tang <tanggeliang@kylinos.cn>
> >
> > Add pm_nl_ctl.
> > Use SYS_NOFAIL in _ss_search().
> >
> > Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> > ---
> > tools/testing/selftests/bpf/Makefile           |  2 +-
> > tools/testing/selftests/bpf/pm_nl_ctl.c        |  1 +
> > tools/testing/selftests/bpf/prog_tests/mptcp.c | 15 ++++-----------
> > 3 files changed, 6 insertions(+), 12 deletions(-)
> > create mode 120000 tools/testing/selftests/bpf/pm_nl_ctl.c
> >
> > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> > index b90c718218ae..bd2e3b138a5c 100644
> > --- a/tools/testing/selftests/bpf/Makefile
> > +++ b/tools/testing/selftests/bpf/Makefile
> > @@ -131,7 +131,7 @@ TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
> >     flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
> >     test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \
> >     xskxceiver xdp_redirect_multi xdp_synproxy veristat xdp_hw_metadata \
> > -   xdp_features bpf_test_no_cfi.ko
> > +   xdp_features bpf_test_no_cfi.ko pm_nl_ctl
> >
> > TEST_GEN_FILES += liburandom_read.so urandom_read sign-file uprobe_multi
> >
> > diff --git a/tools/testing/selftests/bpf/pm_nl_ctl.c b/tools/testing/selftests/bpf/pm_nl_ctl.c
> > new file mode 120000
> > index 000000000000..5a08c255b278
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/pm_nl_ctl.c
> 
> Best to prefix it with "mptcp_": clearer and it will be linked to MPTCP in the maintainers file.

mptcp_ prefix has already added in v2. Please update the maintainers
file when merging this.

> 
> > @@ -0,0 +1 @@
> > +../net/mptcp/pm_nl_ctl.c
> > \ No newline at end of file
> > diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> > index 793b4b9c2bd2..9c6d1e4f6f35 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> > @@ -362,7 +362,8 @@ static int endpoint_init(char *flags)
> >     SYS(fail, "ip -net %s link set dev veth1 up", NS_TEST);
> >     SYS(fail, "ip -net %s addr add %s/24 dev veth2", NS_TEST, ADDR_2);
> >     SYS(fail, "ip -net %s link set dev veth2 up", NS_TEST);
> > -   SYS(fail, "ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags);
> > +   if (SYS_NOFAIL("ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags))
> 
> It is maybe better to only use mptcp_pm_nl_ctl here: to maintain one way here, our CI will do the same as what the BPF one will do, and we avoid errors printed in stderr if "ip mptcp" is not supported.
>

No, I prefer this one. "ip mptcp" should be used here since it's
the normal way to set mptcp. pm_nl_ctl is just a work-around for it.

No error printed in stderr if "ip mptcp" is not supported since
SYS_NOFAIL is used here, not SYS. I have tested this case already.

> > +       SYS(fail, "ip netns exec %s ./pm_nl_ctl add %s flags %s", NS_TEST, ADDR_2, flags);
> >
> >     return 0;
> > fail:
> > @@ -371,16 +372,8 @@ static int endpoint_init(char *flags)
> >
> > static int _ss_search(char *src, char *dst, char *port, char *keyword)
> > {
> > -   char cmd[128];
> > -   int n;
> > -
> > -   n = snprintf(cmd, sizeof(cmd),
> > -            "ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
> > -            NS_TEST, src, dst, port, PORT_1, keyword);
> > -   if (n < 0 || n >= sizeof(cmd))
> > -       return -1;
> > -
> > -   return system(cmd);
> > +   return SYS_NOFAIL("ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
> > +             NS_TEST, src, dst, port, PORT_1, keyword);
> 
> If "ip mptcp" is not supported, I guess "ss -M" will not be supported as well, no?
> 
> Do we need -M here for these tests?

No need to do this yet until we actually encounter it.

Regards,
Geliang

> 
> Cheers,
> Matt
> 
> > }
> >
> > static int ss_search(char *src, char *keyword)
> > --
> > 2.43.0

Re: [PATCH mptcp-next] Squash to "selftests/bpf: Add mptcp subflow subtest"

Posted by Matthieu Baerts 8 months, 1 week ago

Hi Geliang,

12 May 2024 01:17:13 Geliang Tang <geliang@kernel.org>:
> On Sat, May 11, 2024 at 03:50:29PM +0200, Matthieu Baerts wrote:
>> 11 May 2024 12:42:08 Geliang Tang <geliang@kernel.org>:
>>> From: Geliang Tang <tanggeliang@kylinos.cn>

(...)

>>> @@ -0,0 +1 @@
>>> +../net/mptcp/pm_nl_ctl.c
>>> \ No newline at end of file
>>> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>> index 793b4b9c2bd2..9c6d1e4f6f35 100644
>>> --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>> @@ -362,7 +362,8 @@ static int endpoint_init(char *flags)
>>>     SYS(fail, "ip -net %s link set dev veth1 up", NS_TEST);
>>>     SYS(fail, "ip -net %s addr add %s/24 dev veth2", NS_TEST, ADDR_2);
>>>     SYS(fail, "ip -net %s link set dev veth2 up", NS_TEST);
>>> -   SYS(fail, "ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags);
>>> +   if (SYS_NOFAIL("ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags))
>>
>> It is maybe better to only use mptcp_pm_nl_ctl here: to maintain one way here, our CI will do the same as what the BPF one will do, and we avoid errors printed in stderr if "ip mptcp" is not supported.
>>
>
> No, I prefer this one. "ip mptcp" should be used here since it's
> the normal way to set mptcp. pm_nl_ctl is just a work-around for it.
>
> No error printed in stderr if "ip mptcp" is not supported since
> SYS_NOFAIL is used here, not SYS. I have tested this case already.

SYS_NOFAIL doesn't redirect stderr to /dev/null, does it?
If "ip mptcp" is not supported and a fatal error happens, will you not see
in the logs "ip mptcp is not supported" as well, creating confusions?

I would also prefer to use "ip mptcp" if available, but my main reason to
use only the workaround, is: if we change the syntax of pm_nl_ctl, not
realising we have to modify the code here as well, our CI will not
complain, but BPF CI will later, likely when validating something else.
We want our CI to catch such issues before upstreaming patches.

Why not adding a comment instead?

  /* Equivalent of: "ip -net %s mptcp endpoint add %s %s" */

So people interested in knowing how to do that the "proper" way will see
what to do, no?

>
>>> +       SYS(fail, "ip netns exec %s ./pm_nl_ctl add %s flags %s", NS_TEST, ADDR_2, flags);
>>>
>>>     return 0;
>>> fail:
>>> @@ -371,16 +372,8 @@ static int endpoint_init(char *flags)
>>>
>>> static int _ss_search(char *src, char *dst, char *port, char *keyword)
>>> {
>>> -   char cmd[128];
>>> -   int n;
>>> -
>>> -   n = snprintf(cmd, sizeof(cmd),
>>> -            "ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
>>> -            NS_TEST, src, dst, port, PORT_1, keyword);
>>> -   if (n < 0 || n >= sizeof(cmd))
>>> -       return -1;
>>> -
>>> -   return system(cmd);
>>> +   return SYS_NOFAIL("ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
>>> +             NS_TEST, src, dst, port, PORT_1, keyword);
>>
>> If "ip mptcp" is not supported, I guess "ss -M" will not be supported as well, no?
>>
>> Do we need -M here for these tests?
>
> No need to do this yet until we actually encounter it.

"-e" is not needed as well I think. Don't hesitate to remove it as well.

Re: [PATCH mptcp-next] Squash to "selftests/bpf: Add mptcp subflow subtest"

Posted by Geliang Tang 8 months, 1 week ago

On Sun, May 12, 2024 at 11:14:38AM +0200, Matthieu Baerts wrote:
> Hi Geliang,
> 
> 12 May 2024 01:17:13 Geliang Tang <geliang@kernel.org>:
> > On Sat, May 11, 2024 at 03:50:29PM +0200, Matthieu Baerts wrote:
> >> 11 May 2024 12:42:08 Geliang Tang <geliang@kernel.org>:
> >>> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> (...)
> 
> >>> @@ -0,0 +1 @@
> >>> +../net/mptcp/pm_nl_ctl.c
> >>> \ No newline at end of file
> >>> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> >>> index 793b4b9c2bd2..9c6d1e4f6f35 100644
> >>> --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
> >>> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> >>> @@ -362,7 +362,8 @@ static int endpoint_init(char *flags)
> >>>     SYS(fail, "ip -net %s link set dev veth1 up", NS_TEST);
> >>>     SYS(fail, "ip -net %s addr add %s/24 dev veth2", NS_TEST, ADDR_2);
> >>>     SYS(fail, "ip -net %s link set dev veth2 up", NS_TEST);
> >>> -   SYS(fail, "ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags);
> >>> +   if (SYS_NOFAIL("ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags))
> >>
> >> It is maybe better to only use mptcp_pm_nl_ctl here: to maintain one way here, our CI will do the same as what the BPF one will do, and we avoid errors printed in stderr if "ip mptcp" is not supported.
> >>
> >
> > No, I prefer this one. "ip mptcp" should be used here since it's
> > the normal way to set mptcp. pm_nl_ctl is just a work-around for it.
> >
> > No error printed in stderr if "ip mptcp" is not supported since
> > SYS_NOFAIL is used here, not SYS. I have tested this case already.
> 
> SYS_NOFAIL doesn't redirect stderr to /dev/null, does it?
> If "ip mptcp" is not supported and a fatal error happens, will you not see
> in the logs "ip mptcp is not supported" as well, creating confusions?
> 
> I would also prefer to use "ip mptcp" if available, but my main reason to
> use only the workaround, is: if we change the syntax of pm_nl_ctl, not
> realising we have to modify the code here as well, our CI will not
> complain, but BPF CI will later, likely when validating something else.
> We want our CI to catch such issues before upstreaming patches.
> 
> Why not adding a comment instead?
> 
>   /* Equivalent of: "ip -net %s mptcp endpoint add %s %s" */
> 
> So people interested in knowing how to do that the "proper" way will see
> what to do, no?

SYS_NOFAIL is defined in test_progs.h:

388 #define ALL_TO_DEV_NULL " >/dev/null 2>&1"
389
390 #define SYS_NOFAIL(fmt, ...)                                            \
391         ({                                                              \
392                 char cmd[1024];                                         \
393                 int n;                                                  \
394                 n = snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);     \
395                 if (n < sizeof(cmd) && sizeof(cmd) - n >= sizeof(ALL_TO_DEV_NULL)) \
396                         strcat(cmd, ALL_TO_DEV_NULL);                   \
397                 system(cmd);                                            \
398         })

See ALL_TO_DEV_NULL here.

> 
> >
> >>> +       SYS(fail, "ip netns exec %s ./pm_nl_ctl add %s flags %s", NS_TEST, ADDR_2, flags);
> >>>
> >>>     return 0;
> >>> fail:
> >>> @@ -371,16 +372,8 @@ static int endpoint_init(char *flags)
> >>>
> >>> static int _ss_search(char *src, char *dst, char *port, char *keyword)
> >>> {
> >>> -   char cmd[128];
> >>> -   int n;
> >>> -
> >>> -   n = snprintf(cmd, sizeof(cmd),
> >>> -            "ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
> >>> -            NS_TEST, src, dst, port, PORT_1, keyword);
> >>> -   if (n < 0 || n >= sizeof(cmd))
> >>> -       return -1;
> >>> -
> >>> -   return system(cmd);
> >>> +   return SYS_NOFAIL("ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
> >>> +             NS_TEST, src, dst, port, PORT_1, keyword);
> >>
> >> If "ip mptcp" is not supported, I guess "ss -M" will not be supported as well, no?
> >>
> >> Do we need -M here for these tests?
> >
> > No need to do this yet until we actually encounter it.
> 
> "-e" is not needed as well I think. Don't hesitate to remove it as well.

"-e" is needed by has_bytes_sent:

458 static int has_bytes_sent(char *dst)
459 {
460         return _ss_search(ADDR_1, dst, "sport", "bytes_sent:");
461 }

BPF sched tests fail if remove it.

Regards,
Geliang

Re: [PATCH mptcp-next] Squash to "selftests/bpf: Add mptcp subflow subtest"

Posted by Matthieu Baerts 8 months, 1 week ago

12 May 2024 13:45:15 Geliang Tang <geliang@kernel.org>:

> On Sun, May 12, 2024 at 11:14:38AM +0200, Matthieu Baerts wrote:
>> Hi Geliang,
>>
>> 12 May 2024 01:17:13 Geliang Tang <geliang@kernel.org>:
>>> On Sat, May 11, 2024 at 03:50:29PM +0200, Matthieu Baerts wrote:
>>>> 11 May 2024 12:42:08 Geliang Tang <geliang@kernel.org>:
>>>>> From: Geliang Tang <tanggeliang@kylinos.cn>
>>
>> (...)
>>
>>>>> @@ -0,0 +1 @@
>>>>> +../net/mptcp/pm_nl_ctl.c
>>>>> \ No newline at end of file
>>>>> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>>>> index 793b4b9c2bd2..9c6d1e4f6f35 100644
>>>>> --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>>>> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>>>> @@ -362,7 +362,8 @@ static int endpoint_init(char *flags)
>>>>>     SYS(fail, "ip -net %s link set dev veth1 up", NS_TEST);
>>>>>     SYS(fail, "ip -net %s addr add %s/24 dev veth2", NS_TEST, ADDR_2);
>>>>>     SYS(fail, "ip -net %s link set dev veth2 up", NS_TEST);
>>>>> -   SYS(fail, "ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags);
>>>>> +   if (SYS_NOFAIL("ip -net %s mptcp endpoint add %s %s", NS_TEST, ADDR_2, flags))
>>>>
>>>> It is maybe better to only use mptcp_pm_nl_ctl here: to maintain one way here, our CI will do the same as what the BPF one will do, and we avoid errors printed in stderr if "ip mptcp" is not supported.
>>>>
>>>
>>> No, I prefer this one. "ip mptcp" should be used here since it's
>>> the normal way to set mptcp. pm_nl_ctl is just a work-around for it.
>>>
>>> No error printed in stderr if "ip mptcp" is not supported since
>>> SYS_NOFAIL is used here, not SYS. I have tested this case already.
>>
>> SYS_NOFAIL doesn't redirect stderr to /dev/null, does it?
>> If "ip mptcp" is not supported and a fatal error happens, will you not see
>> in the logs "ip mptcp is not supported" as well, creating confusions?
>>
>> I would also prefer to use "ip mptcp" if available, but my main reason to
>> use only the workaround, is: if we change the syntax of pm_nl_ctl, not
>> realising we have to modify the code here as well, our CI will not
>> complain, but BPF CI will later, likely when validating something else.
>> We want our CI to catch such issues before upstreaming patches.
>>
>> Why not adding a comment instead?
>>
>>   /* Equivalent of: "ip -net %s mptcp endpoint add %s %s" */
>>
>> So people interested in knowing how to do that the "proper" way will see
>> what to do, no?
>
> SYS_NOFAIL is defined in test_progs.h:
>
> 388 #define ALL_TO_DEV_NULL " >/dev/null 2>&1"
> 389
> 390 #define SYS_NOFAIL(fmt, ...)                                            \
> 391         ({                                                              \
> 392                 char cmd[1024];                                         \
> 393                 int n;                                                  \
> 394                 n = snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);     \
> 395                 if (n < sizeof(cmd) && sizeof(cmd) - n >= sizeof(ALL_TO_DEV_NULL)) \
> 396                         strcat(cmd, ALL_TO_DEV_NULL);                   \
> 397                 system(cmd);                                            \
> 398         })
>
> See ALL_TO_DEV_NULL here.

My bad, I was looking at the code from v6.8.

But still, I think it would be better to avoid sending patches upstream
and potentially breaking stuff on BPF side because we didn't test
the same way as what is done on their side, no?

>
>>
>>>
>>>>> +       SYS(fail, "ip netns exec %s ./pm_nl_ctl add %s flags %s", NS_TEST, ADDR_2, flags);
>>>>>
>>>>>     return 0;
>>>>> fail:
>>>>> @@ -371,16 +372,8 @@ static int endpoint_init(char *flags)
>>>>>
>>>>> static int _ss_search(char *src, char *dst, char *port, char *keyword)
>>>>> {
>>>>> -   char cmd[128];
>>>>> -   int n;
>>>>> -
>>>>> -   n = snprintf(cmd, sizeof(cmd),
>>>>> -            "ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
>>>>> -            NS_TEST, src, dst, port, PORT_1, keyword);
>>>>> -   if (n < 0 || n >= sizeof(cmd))
>>>>> -       return -1;
>>>>> -
>>>>> -   return system(cmd);
>>>>> +   return SYS_NOFAIL("ip netns exec %s ss -Menita src %s dst %s %s %d | grep -q '%s'",
>>>>> +             NS_TEST, src, dst, port, PORT_1, keyword);
>>>>
>>>> If "ip mptcp" is not supported, I guess "ss -M" will not be supported as well, no?
>>>>
>>>> Do we need -M here for these tests?
>>>
>>> No need to do this yet until we actually encounter it.
>>
>> "-e" is not needed as well I think. Don't hesitate to remove it as well.
>
> "-e" is needed by has_bytes_sent:
>
> 458 static int has_bytes_sent(char *dst)
> 459 {
> 460         return _ss_search(ADDR_1, dst, "sport", "bytes_sent:");
> 461 }
>
> BPF sched tests fail if remove it.

Thank you for having checked! It looks like ss' man page is missing
this case.

Cheers,
Matt