netdev - Re: [PATCH net-next v4 4/6] tcp: support rstreason for passive reset

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Message-ID: <CAL+tcoB=Hr8s+j7Sm8viF-=3aHwhEevZZcpn5ek0RYmNowAtoQ@mail.gmail.com>
Date: Tue, 16 Apr 2024 15:45:07 +0800
From: Jason Xing <kerneljasonxing@...il.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: dsahern@...nel.org, matttbe@...nel.org, martineau@...nel.org, 
	geliang@...nel.org, kuba@...nel.org, pabeni@...hat.com, davem@...emloft.net, 
	rostedt@...dmis.org, mhiramat@...nel.org, mathieu.desnoyers@...icios.com, 
	atenart@...nel.org, mptcp@...ts.linux.dev, netdev@...r.kernel.org, 
	Jason Xing <kernelxing@...cent.com>
Subject: Re: [PATCH net-next v4 4/6] tcp: support rstreason for passive reset

On Tue, Apr 16, 2024 at 2:34 PM Eric Dumazet <edumazet@...gle.com> wrote:
>
> On Thu, Apr 11, 2024 at 1:57 PM Jason Xing <kerneljasonxing@...il.com> wrote:
> >
> > From: Jason Xing <kernelxing@...cent.com>
> >
> > Reuse the dropreason logic to show the exact reason of tcp reset,
> > so we don't need to implement those duplicated reset reasons.
> > This patch replaces all the prior NOT_SPECIFIED reasons.
> >
> > Signed-off-by: Jason Xing <kernelxing@...cent.com>
> > ---
> >  net/ipv4/tcp_ipv4.c | 8 ++++----
> >  net/ipv6/tcp_ipv6.c | 8 ++++----
> >  2 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> > index 441134aebc51..863397c2a47b 100644
> > --- a/net/ipv4/tcp_ipv4.c
> > +++ b/net/ipv4/tcp_ipv4.c
> > @@ -1935,7 +1935,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
> >         return 0;
> >
> >  reset:
> > -       tcp_v4_send_reset(rsk, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +       tcp_v4_send_reset(rsk, skb, (u32)reason);
> >  discard:
> >         kfree_skb_reason(skb, reason);
> >         /* Be careful here. If this function gets more complicated and
> > @@ -2278,7 +2278,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
> >                 } else {
> >                         drop_reason = tcp_child_process(sk, nsk, skb);
> >                         if (drop_reason) {
> > -                               tcp_v4_send_reset(nsk, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +                               tcp_v4_send_reset(nsk, skb, (u32)drop_reason);
>
> Are all these casts really needed ?

Not really. If without, the compiler wouldn't complain about it.

>
> enum sk_rst_reason is not the same as u32 anyway ?

I will remove the cast in the next version.

Thanks,
Jason

>
>
>
> >                                 goto discard_and_relse;
> >                         }
> >                         sock_put(sk);
> > @@ -2356,7 +2356,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
> >  bad_packet:
> >                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
> >         } else {
> > -               tcp_v4_send_reset(NULL, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +               tcp_v4_send_reset(NULL, skb, (u32)drop_reason);
> >         }
> >
> >  discard_it:
> > @@ -2407,7 +2407,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
> >                 tcp_v4_timewait_ack(sk, skb);
> >                 break;
> >         case TCP_TW_RST:
> > -               tcp_v4_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +               tcp_v4_send_reset(sk, skb, (u32)drop_reason);
> >                 inet_twsk_deschedule_put(inet_twsk(sk));
> >                 goto discard_it;
> >         case TCP_TW_SUCCESS:;
> > diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
> > index 6cad32430a12..ba9d9ceb7e89 100644
> > --- a/net/ipv6/tcp_ipv6.c
> > +++ b/net/ipv6/tcp_ipv6.c
> > @@ -1678,7 +1678,7 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
> >         return 0;
> >
> >  reset:
> > -       tcp_v6_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +       tcp_v6_send_reset(sk, skb, (u32)reason);
> >  discard:
> >         if (opt_skb)
> >                 __kfree_skb(opt_skb);
> > @@ -1864,7 +1864,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
> >                 } else {
> >                         drop_reason = tcp_child_process(sk, nsk, skb);
> >                         if (drop_reason) {
> > -                               tcp_v6_send_reset(nsk, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +                               tcp_v6_send_reset(nsk, skb, (u32)drop_reason);
> >                                 goto discard_and_relse;
> >                         }
> >                         sock_put(sk);
> > @@ -1940,7 +1940,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
> >  bad_packet:
> >                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
> >         } else {
> > -               tcp_v6_send_reset(NULL, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +               tcp_v6_send_reset(NULL, skb, (u32)drop_reason);
> >         }
> >
> >  discard_it:
> > @@ -1995,7 +1995,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
> >                 tcp_v6_timewait_ack(sk, skb);
> >                 break;
> >         case TCP_TW_RST:
> > -               tcp_v6_send_reset(sk, skb, SK_RST_REASON_NOT_SPECIFIED);
> > +               tcp_v6_send_reset(sk, skb, (u32)drop_reason);
> >                 inet_twsk_deschedule_put(inet_twsk(sk));
> >                 goto discard_it;
> >         case TCP_TW_SUCCESS:
> > --
> > 2.37.3
> >