[PATCH mptcp-next v4 0/2] send MP_FAIL with MP_RST and others

[PATCH mptcp-next v4 0/2] send MP_FAIL with MP_RST and others

[Geliang Tang]

v4:
 - add Matt's patch, fix the missing ";" in it, dropped two empty lines
and added my Tested-by tag.

v3:
 - update patch 1 as Matt suggested.
 - do more cleanups in patch 1.

v2:
 - rename patch 1 as a squash-to patch.
 - print out reset_transient in patch 2 too. Please keep patch 2 as a
standalone patch, not a squash-to patch.

Two small patches about sending MP_FAIL with MP_RST.

Geliang Tang (1):
  mptcp: print out reset infos of MP_RST

Matthieu Baerts (1):
  Squash to "mptcp: implement fastclose xmit path"

 net/mptcp/options.c | 62 +++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 25 deletions(-)

-- 
2.31.1

[PATCH mptcp-next v4 1/2] Squash to "mptcp: implement fastclose xmit path"

[Geliang Tang]

From: Matthieu Baerts <matthieu.baerts@tessares.net>

This is linked to Geliang's patch with the same title.

If I understand the RFC properly, we can use MP_RST with an MP_FASTCLOSE
and an MP_FAIL (or none of them) but we cannot use MP_FASTCLOSE and
MP_FAIL together.

This patch implements this logic in both mptcp_established_options() and
mptcp_write_options(). Before this patch, the first function was not
allowing any of these 3 options to be used at the same time while the
second one was allowing MP_FAIL to be used with either MP_FASTCLOSE or
MP_RST.

Small note: I tried to keep Paolo's idea of reducing conditions for
"normal" options by moving MP_RST at the end and allow to jump there
from MP_FAIL and MP_FASTCLOSE but I'm not sure it makes it easy to read
and really improves perfs. We can also move MP_RST check at the
beginning.

Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Tested-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
 net/mptcp/options.c | 60 ++++++++++++++++++++++++++-------------------
 1 file changed, 35 insertions(+), 25 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 8a1020e4285c..078187456467 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -829,8 +829,12 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 
 	if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) {
 		if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) ||
-		    mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts) ||
-		    mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
+		    mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
+			*size += opt_size;
+			remaining -= opt_size;
+		}
+		/* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */
+		if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
 			*size += opt_size;
 			remaining -= opt_size;
 		}
@@ -1257,21 +1261,7 @@ static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 			 struct mptcp_out_options *opts)
 {
-	if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
-		const struct sock *ssk = (const struct sock *)tp;
-		struct mptcp_subflow_context *subflow;
-
-		subflow = mptcp_subflow_ctx(ssk);
-		subflow->send_mp_fail = 0;
-
-		*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
-				      TCPOLEN_MPTCP_FAIL,
-				      0, 0);
-		put_unaligned_be64(opts->fail_seq, ptr);
-		ptr += 2;
-	}
-
-	/* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,
+	/* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and FAIL are mutually exclusive,
 	 * see mptcp_established_options*()
 	 */
 	if (likely(OPTION_MPTCP_DSS & opts->suboptions)) {
@@ -1458,19 +1448,39 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 				ptr += 1;
 			}
 		}
-	} else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) {
-		/* RST is mutually exclusive with everything else */
-		*ptr++ = mptcp_option(MPTCPOPT_RST,
-				      TCPOLEN_MPTCP_RST,
-				      opts->reset_transient,
-				      opts->reset_reason);
-		return;
 	} else if (unlikely(OPTION_MPTCP_FASTCLOSE & opts->suboptions)) {
-		/* FASTCLOSE is mutually exclusive with everything else */
+		/* FASTCLOSE is mutually exclusive with others except RST */
 		*ptr++ = mptcp_option(MPTCPOPT_MP_FASTCLOSE,
 				      TCPOLEN_MPTCP_FASTCLOSE,
 				      0, 0);
 		put_unaligned_be64(opts->rcvr_key, ptr);
+
+		if (OPTION_MPTCP_RST & opts->suboptions)
+			goto mp_rst;
+		return;
+	} else if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
+		/* MP_FAIL is mutually exclusive with others except RST */
+		const struct sock *ssk = (const struct sock *)tp;
+		struct mptcp_subflow_context *subflow;
+
+		subflow = mptcp_subflow_ctx(ssk);
+		subflow->send_mp_fail = 0;
+
+		*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
+				      TCPOLEN_MPTCP_FAIL,
+				      0, 0);
+		put_unaligned_be64(opts->fail_seq, ptr);
+		ptr += 2;
+
+		if (OPTION_MPTCP_RST & opts->suboptions)
+			goto mp_rst;
+		return;
+	} else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) {
+mp_rst:
+		*ptr++ = mptcp_option(MPTCPOPT_RST,
+				      TCPOLEN_MPTCP_RST,
+				      opts->reset_transient,
+				      opts->reset_reason);
 		return;
 	}
 
-- 
2.31.1

[PATCH mptcp-next v4 2/2] mptcp: print out reset infos of MP_RST

[Geliang Tang]

This patch printed out the reset infos, reset_transient and reset_reason,
of MP_RST in mptcp_parse_option() to show that MP_RST is received.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/options.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 078187456467..efb828a4edaa 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -336,6 +336,8 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 		flags = *ptr++;
 		mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT;
 		mp_opt->reset_reason = *ptr;
+		pr_debug("MP_RST: transient=%u reason=%u",
+			 mp_opt->reset_transient, mp_opt->reset_reason);
 		break;
 
 	case MPTCPOPT_MP_FAIL:
-- 
2.31.1

Re: [PATCH mptcp-next v4 1/2] Squash to "mptcp: implement fastclose xmit path"

[Geliang Tang]

Sorry, this patch still needs to be improved.

I just notice that MP_FAIL will be sent with DSS too.

In the multiple subflow case, MP_FAIL will be sent with MP_RST,
But in the single subflow case, MP_FAIL will be sent with DSS.

I'll sent a new version of this squash-to patch later.

Thanks,
-Geliang

Geliang Tang <geliang.tang@suse.com> 于2021年12月2日周四 12:26写道：
>
> From: Matthieu Baerts <matthieu.baerts@tessares.net>
>
> This is linked to Geliang's patch with the same title.
>
> If I understand the RFC properly, we can use MP_RST with an MP_FASTCLOSE
> and an MP_FAIL (or none of them) but we cannot use MP_FASTCLOSE and
> MP_FAIL together.
>
> This patch implements this logic in both mptcp_established_options() and
> mptcp_write_options(). Before this patch, the first function was not
> allowing any of these 3 options to be used at the same time while the
> second one was allowing MP_FAIL to be used with either MP_FASTCLOSE or
> MP_RST.
>
> Small note: I tried to keep Paolo's idea of reducing conditions for
> "normal" options by moving MP_RST at the end and allow to jump there
> from MP_FAIL and MP_FASTCLOSE but I'm not sure it makes it easy to read
> and really improves perfs. We can also move MP_RST check at the
> beginning.
>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Geliang Tang <geliang.tang@suse.com>
> Tested-by: Geliang Tang <geliang.tang@suse.com>
> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
> ---
>  net/mptcp/options.c | 60 ++++++++++++++++++++++++++-------------------
>  1 file changed, 35 insertions(+), 25 deletions(-)
>
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index 8a1020e4285c..078187456467 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -829,8 +829,12 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
>
>         if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) {
>                 if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) ||
> -                   mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts) ||
> -                   mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
> +                   mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
> +                       *size += opt_size;
> +                       remaining -= opt_size;
> +               }
> +               /* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */
> +               if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
>                         *size += opt_size;
>                         remaining -= opt_size;
>                 }
> @@ -1257,21 +1261,7 @@ static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
>  void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
>                          struct mptcp_out_options *opts)
>  {
> -       if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
> -               const struct sock *ssk = (const struct sock *)tp;
> -               struct mptcp_subflow_context *subflow;
> -
> -               subflow = mptcp_subflow_ctx(ssk);
> -               subflow->send_mp_fail = 0;
> -
> -               *ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
> -                                     TCPOLEN_MPTCP_FAIL,
> -                                     0, 0);
> -               put_unaligned_be64(opts->fail_seq, ptr);
> -               ptr += 2;
> -       }
> -
> -       /* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,
> +       /* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and FAIL are mutually exclusive,
>          * see mptcp_established_options*()
>          */
>         if (likely(OPTION_MPTCP_DSS & opts->suboptions)) {
> @@ -1458,19 +1448,39 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
>                                 ptr += 1;
>                         }
>                 }
> -       } else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) {
> -               /* RST is mutually exclusive with everything else */
> -               *ptr++ = mptcp_option(MPTCPOPT_RST,
> -                                     TCPOLEN_MPTCP_RST,
> -                                     opts->reset_transient,
> -                                     opts->reset_reason);
> -               return;
>         } else if (unlikely(OPTION_MPTCP_FASTCLOSE & opts->suboptions)) {
> -               /* FASTCLOSE is mutually exclusive with everything else */
> +               /* FASTCLOSE is mutually exclusive with others except RST */
>                 *ptr++ = mptcp_option(MPTCPOPT_MP_FASTCLOSE,
>                                       TCPOLEN_MPTCP_FASTCLOSE,
>                                       0, 0);
>                 put_unaligned_be64(opts->rcvr_key, ptr);
> +
> +               if (OPTION_MPTCP_RST & opts->suboptions)
> +                       goto mp_rst;
> +               return;
> +       } else if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
> +               /* MP_FAIL is mutually exclusive with others except RST */
> +               const struct sock *ssk = (const struct sock *)tp;
> +               struct mptcp_subflow_context *subflow;
> +
> +               subflow = mptcp_subflow_ctx(ssk);
> +               subflow->send_mp_fail = 0;
> +
> +               *ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
> +                                     TCPOLEN_MPTCP_FAIL,
> +                                     0, 0);
> +               put_unaligned_be64(opts->fail_seq, ptr);
> +               ptr += 2;
> +
> +               if (OPTION_MPTCP_RST & opts->suboptions)
> +                       goto mp_rst;
> +               return;
> +       } else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) {
> +mp_rst:
> +               *ptr++ = mptcp_option(MPTCPOPT_RST,
> +                                     TCPOLEN_MPTCP_RST,
> +                                     opts->reset_transient,
> +                                     opts->reset_reason);
>                 return;
>         }
>
> --
> 2.31.1
>
>