Re: [PATCH net v2 2/2] selftests/net: psp: test bidirectional data transfer

[Wei Wang]

On Wed, Nov 4, 2026 at 1:26 PM Daniel Zahka <daniel.zahka@xxxxxxxxx> wrote:
>
> On Fri Oct 30, 2026 at 12:31 AM EDT, Wei Wang wrote:
> > _data_basic_send() and _data_basic_send_netkit_psp_assoc() currently
> > only verify unidirectional data transmission from the test socket to
> > psp_responder. As a result, they do not exercise the receive path for
> > PSP-encrypted TCP data segments arriving at the test socket (such as
> > packets redirected across a netkit interface associated via dev-assoc,
> > which relies on SKB_EXT_PSP surviving packet scrubbing).
> >
> > Use the existing "data echo" command in psp_responder to verify that the
> > test socket can also receive PSP-encrypted data from the peer in both
> > _data_basic_send() and _data_basic_send_netkit_psp_assoc().
> >
> > Signed-off-by: Wei Wang <weiwan@xxxxxxxxxx>
> > ---
> >  tools/testing/selftests/drivers/net/psp.py | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/tools/testing/selftests/drivers/net/psp.py b/tools/testing/selftests/drivers/net/psp.py
> > index 473500901879..e507951b440b 100755
> > --- a/tools/testing/selftests/drivers/net/psp.py
> > +++ b/tools/testing/selftests/drivers/net/psp.py
> > @@ -120,6 +120,12 @@ def _check_data_rx(cfg, exp_len):
> >      ksft_eq(read_len, exp_len)
> >
> >
> > +def _check_data_echo(cfg, s):
> > +    _send_with_ack(cfg, b'data echo\0')
> > +    s.settimeout(1.0)
>
> I'm not a huge fan of setting the blocking timeout here. If we are going
> to set a timeout it should be when the socket is created. Otherwise this
> function has an unexpected side-effect. Another option is to use non
> blocking reads with timeout like:
>

Will switch to non blocking reads in next version.

> def _recv_careful(s, target, timeout=2):
>     """Read exactly target bytes, tolerating short reads"""
>     data = b''
>     end = time.monotonic() + timeout
>     while time.monotonic() < end:
>         try:
>             data += s.recv(target - len(data), socket.MSG_DONTWAIT)
>             if len(data) == target:
>                 return data
>         except BlockingIOError:
>             time.sleep(0.001)
>     raise KsftFailEx(f"short read, got {len(data)} of {target} bytes")
>
>
> def _req_echo(cfg, s):
>     """Ask the peer to echo, and check the reply arrives intact"""
>     _send_with_ack(cfg, b'data echo\0')
>     ksft_eq(_recv_careful(s, 5), b'echo\0')
>
> > +    ksft_eq(s.recv(5), b'echo\0')
> > +
> > +
> >  def _check_data_outq(s, exp_len, force_wait=False):
> >      outq = 0
> >      for _ in range(10):
> > @@ -478,6 +484,7 @@ def _data_basic_send(cfg, version, ipver):
> >
> >      data_len = _send_careful(cfg, s, 100)
> >      _check_data_rx(cfg, data_len)
> > +    _check_data_echo(cfg, s)
> >      _close_psp_conn(cfg, s)
> >
> >
> > @@ -726,6 +733,7 @@ def _data_basic_send_netkit_psp_assoc(cfg, version, ipver):
> >
> >          data_len = _send_careful(cfg, sock, 100)
> >          _check_data_rx(cfg, data_len)
> > +        _check_data_echo(cfg, sock)
> >          _close_psp_conn(cfg, sock)
> >
> >
>
> I'm ok with the approach overall. The coverage is sufficient for the
> purposes of the series.