Re: Re: [PATCH bpf-next v2] bpf: Fix bpf_get/setsockopt to tos not take effect when TCP over IPv4 via INET6 API

[Feng Zhou]

在 2024/9/13 22:44, Eric Dumazet 写道:
> On Tue, Aug 27, 2024 at 10:08 AM Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx> wrote:
> > 在 2024/8/24 02:53, Eric Dumazet 写道:
> > > On Fri, Aug 23, 2024 at 8:49 PM Martin KaFai Lau <martin.lau@xxxxxxxxx> wrote:
> > > > On 8/23/24 6:35 AM, Eric Dumazet wrote:
> > > > > On Fri, Aug 23, 2024 at 10:53 AM Feng zhou <zhoufeng.zf@xxxxxxxxxxxxx> wrote:
> > > > > > From: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
> > > > > >
> > > > > > when TCP over IPv4 via INET6 API, bpf_get/setsockopt with ipv4 will
> > > > > > fail, because sk->sk_family is AF_INET6. With ipv6 will success, not
> > > > > > take effect, because inet_csk(sk)->icsk_af_ops is ipv6_mapped and
> > > > > > use ip_queue_xmit, inet_sk(sk)->tos.
> > > > > >
> > > > > > So bpf_get/setsockopt needs add the judgment of this case. Just check
> > > > > > "inet_csk(sk)->icsk_af_ops == &ipv6_mapped".
> > > > > >
> > > > > > | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > > > > > | Closes: https://lore.kernel.org/oe-kbuild-all/202408152034.lw9Ilsj6-lkp@xxxxxxxxx/
> > > > > > Signed-off-by: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
> > > > > > ---
> > > > > > Changelog:
> > > > > > v1->v2: Addressed comments from kernel test robot
> > > > > > - Fix compilation error
> > > > > > Details in here:
> > > > > > https://lore.kernel.org/bpf/202408152058.YXAnhLgZ-lkp@xxxxxxxxx/T/
> > > > > >
> > > > > >     include/net/tcp.h   | 2 ++
> > > > > >     net/core/filter.c   | 6 +++++-
> > > > > >     net/ipv6/tcp_ipv6.c | 6 ++++++
> > > > > >     3 files changed, 13 insertions(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/include/net/tcp.h b/include/net/tcp.h
> > > > > > index 2aac11e7e1cc..ea673f88c900 100644
> > > > > > --- a/include/net/tcp.h
> > > > > > +++ b/include/net/tcp.h
> > > > > > @@ -493,6 +493,8 @@ struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
> > > > > >                                                struct tcp_options_received *tcp_opt,
> > > > > >                                                int mss, u32 tsoff);
> > > > > >
> > > > > > +bool is_tcp_sock_ipv6_mapped(struct sock *sk);
> > > > > > +
> > > > > >     #if IS_ENABLED(CONFIG_BPF)
> > > > > >     struct bpf_tcp_req_attrs {
> > > > > >            u32 rcv_tsval;
> > > > > > diff --git a/net/core/filter.c b/net/core/filter.c
> > > > > > index ecf2ddf633bf..02a825e35c4d 100644
> > > > > > --- a/net/core/filter.c
> > > > > > +++ b/net/core/filter.c
> > > > > > @@ -5399,7 +5399,11 @@ static int sol_ip_sockopt(struct sock *sk, int optname,
> > > > > >                              char *optval, int *optlen,
> > > > > >                              bool getopt)
> > > > > >     {
> > > > > > -       if (sk->sk_family != AF_INET)
> > > > > > +       if (sk->sk_family != AF_INET
> > > > > > +#if IS_BUILTIN(CONFIG_IPV6)
> > > > > > +           && !is_tcp_sock_ipv6_mapped(sk)
> > > > > > +#endif
> > > > > > +           )
> > > > > >                    return -EINVAL;
> > > > >
> > > > > This does not look right to me.
> > > > >
> > > > > I would remove the test completely.
> > > > >
> > > > > SOL_IP socket options are available on AF_INET6 sockets just fine.
> > > >
> > > > Good point on the SOL_IP options.
> > > >
> > > > The sk could be neither AF_INET nor AF_INET6. e.g. the bpf_get/setsockopt
> > > > calling from the bpf_lsm's socket_post_create). so the AF_INET test is still needed.
> > >
> > > OK, then I suggest using sk_is_inet() helper.
> > >
> > > > Adding "&& sk->sk_family != AF_INET6" should do. From ipv6_setsockopt, I think
> > > > it also needs to consider the "sk->sk_type != SOCK_RAW".
> > > >
> > > > Please add a test in the next re-spin.
> > > >
> > > > pw-bot: cr
> >
> > Thanks for your suggestion, I will add it in the next version.
>
> Gentle ping.
>
> Have you sent the new version ?

Sorry, there have been a lot of delays in work recently. V3 will be sent 
in two days. Thanks.