On Tue, Feb 5, 2019 at 1:35 AM Alexei Starovoitov
<alexei.starovoi...@gmail.com> wrote:
>
> On Sun, Feb 03, 2019 at 04:15:07PM +0800, Yafang Shao wrote:
> > Then we can enable/disable socket debugging without modifying user code.
> > That is more convenient for debugging.
> >
> > Signed-off-by: Yafang Shao <laoar.s...@gmail.com>
> > ---
> > include/net/sock.h | 8 ++++++++
> > net/core/filter.c | 3 +++
> > net/core/sock.c | 8 --------
> > 3 files changed, 11 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/net/sock.h b/include/net/sock.h
> > index 2b229f7..8decee9 100644
> > --- a/include/net/sock.h
> > +++ b/include/net/sock.h
> > @@ -1935,6 +1935,14 @@ static inline void sock_confirm_neigh(struct sk_buff
> > *skb, struct neighbour *n)
> > }
> > }
> >
> > +static inline void sock_valbool_flag(struct sock *sk, int bit, int valbool)
> > +{
> > + if (valbool)
> > + sock_set_flag(sk, bit);
> > + else
> > + sock_reset_flag(sk, bit);
> > +}
> > +
> > bool sk_mc_loop(struct sock *sk);
> >
> > static inline bool sk_can_gso(const struct sock *sk)
> > diff --git a/net/core/filter.c b/net/core/filter.c
> > index 3a49f68..ce5da57 100644
> > --- a/net/core/filter.c
> > +++ b/net/core/filter.c
> > @@ -4111,6 +4111,9 @@ static unsigned long bpf_xdp_copy(void *dst_buff,
> > const void *src_buff,
> >
> > /* Only some socketops are supported */
> > switch (optname) {
> > + case SO_DEBUG:
> > + sock_valbool_flag(sk, SOCK_DBG, val);
> > + break;
>
> I'm missing the point here.
> This flag has any effect only when SOCK_DEBUGGING is set.
> But it is off in distros.
It's not off in distros. At least it is set in RHEL.
Pls. see the comment in include/net/sock.h,
/* Define this to get the SOCK_DBG debugging facility. */
#define SOCK_DEBUGGING
> Since it's for custom debug kernel only why bother with
> setting the flag via bpf prog?
>
