Re: [PATCH net v4 2/2] selftests: net: add TAP socket filter attach tests

Rongguang Wei wrote:

From: Rongguang Wei <redacted>

reattach_filter_without_user_buffer() attaches a filter, makes the buffer
the program was copied from unreadable, detaches the queue and attaches it
again. It then attaches a second queue from a fresh socket, which starts
without a filter of its own, so a clear IFF_NOFILTER shows that the filter
was installed again from the kernel copy.

attach_filter_bad_len_keeps_program() checks that a rejected
TUNATTACHFILTER leaves the installed program and the filter state that
TUNGETIFF reports alone, and that a queue attached afterwards still gets
the filter.

attach_filter_nofilter_flag() and detach_filter_clears_reattach() cover the
ways to attach a queue without a filter.

Signed-off-by: Rongguang Wei <redacted>

Reviewed-by: Willem de Bruijn <willemb@google.com>