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From: Geliang Tang <geliangtang@gmail.com>
To: Jianguo Wu <wujianguo106@163.com>
Cc: mptcp@lists.linux.dev, Paolo Abeni <pabeni@redhat.com>,
	 Mat Martineau <mathew.j.martineau@linux.intel.com>
Subject: Re: [PATCH mptcp-net v7 4/5] mptcp: avoid processing packet if a subflow reset
Date: Fri, 25 Jun 2021 16:58:19 +0800	[thread overview]
Message-ID: <CA+WQbwtE-UTpORMrSZFidAbcGaZBoRQv-BzR+2juxOt7kjfurA@mail.gmail.com> (raw)
In-Reply-To: <1624609559-6786-5-git-send-email-wujianguo106@163.com>

Hi Jianguo,

Thank you for this patchset!

<wujianguo106@163.com> 于2021年6月25日周五 下午4:26写道:
>
> From: Jianguo Wu <wujianguo@chinatelecom.cn>
>
> If check_fully_established() causes a subflow reset, it should not
> continue to process the packet in tcp_data_queue().
> Add a return value to mptcp_incoming_options(), and return 0 if a
> subflow has been reset, else return 1. Then drop the packet in
> tcp_data_queue()/tcp_rcv_state_process() if mptcp_incoming_options()
> return 0.
>
> Fixes: d582484726c4 ("mptcp: fix fallback for MP_JOIN subflows")
> Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn>
> ---
>  include/net/mptcp.h  |  5 +++--
>  net/ipv4/tcp_input.c | 19 +++++++++++++++----
>  net/mptcp/options.c  | 22 ++++++++++++++--------
>  3 files changed, 32 insertions(+), 14 deletions(-)
>
> diff --git a/include/net/mptcp.h b/include/net/mptcp.h
> index cb580b0..cbd511c 100644
> --- a/include/net/mptcp.h
> +++ b/include/net/mptcp.h
> @@ -105,7 +105,7 @@ bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
>  bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
>                                unsigned int *size, unsigned int remaining,
>                                struct mptcp_out_options *opts);
> -void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
> +int mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
>
>  void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
>                          struct mptcp_out_options *opts);
> @@ -227,9 +227,10 @@ static inline bool mptcp_established_options(struct sock *sk,
>         return false;
>  }
>
> -static inline void mptcp_incoming_options(struct sock *sk,
> +static inline int mptcp_incoming_options(struct sock *sk,
>                                           struct sk_buff *skb)
>  {
> +       return 1;
>  }
>
>  static inline void mptcp_skb_ext_move(struct sk_buff *to,
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 7d5e59f..4bacd7d 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -4247,6 +4247,9 @@ void tcp_reset(struct sock *sk, struct sk_buff *skb)
>  {
>         trace_tcp_receive_reset(sk);
>
> +       /* mptcp can't tell us to ignore reset pkts,
> +        * so just ignore the return value of mptcp_incoming_options().
> +        */
>         if (sk_is_mptcp(sk))
>                 mptcp_incoming_options(sk, skb);
>
> @@ -4941,8 +4944,13 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
>         bool fragstolen;
>         int eaten;
>
> -       if (sk_is_mptcp(sk))
> -               mptcp_incoming_options(sk, skb);
> +       /* If a subflow has been reset, the packet should not continue
> +        * to be processed, drop the packet.
> +        */
> +       if (sk_is_mptcp(sk) && !mptcp_incoming_options(sk, skb)) {
> +               __kfree_skb(skb);
> +               return;
> +       }
>
>         if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
>                 __kfree_skb(skb);
> @@ -6523,8 +6531,11 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
>         case TCP_CLOSING:
>         case TCP_LAST_ACK:
>                 if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
> -                       if (sk_is_mptcp(sk))
> -                               mptcp_incoming_options(sk, skb);
> +                       /* If a subflow has been reset, the packet should not
> +                        * continue to be processed, drop the packet.
> +                        */
> +                       if (sk_is_mptcp(sk) && !mptcp_incoming_options(sk, skb))
> +                               goto discard;
>                         break;
>                 }
>                 fallthrough;
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index b5850af..f4842b5 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -856,7 +856,8 @@ bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
>  static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
>                                     struct mptcp_subflow_context *subflow,
>                                     struct sk_buff *skb,
> -                                   struct mptcp_options_received *mp_opt)
> +                                   struct mptcp_options_received *mp_opt,
> +                                   bool *subflow_is_rst)
>  {
>         /* here we can process OoO, in-window pkts, only in-sequence 4th ack
>          * will make the subflow fully established
> @@ -938,6 +939,7 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
>         return true;
>
>  reset:
> +       *subflow_is_rst = true;
>         mptcp_subflow_reset(ssk);
>         return false;
>  }
> @@ -1035,12 +1037,14 @@ static bool add_addr_hmac_valid(struct mptcp_sock *msk,
>         return hmac == mp_opt->ahmac;
>  }
>
> -void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
> +/* Return 0 if a subflow has been reset, else return 1 */

How about returning a bool here, return true or return false?

-Geliang

> +int mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
>  {
>         struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
>         struct mptcp_sock *msk = mptcp_sk(subflow->conn);
>         struct mptcp_options_received mp_opt;
>         struct mptcp_ext *mpext;
> +       bool subflow_is_rst = false;
>
>         if (__mptcp_check_fallback(msk)) {
>                 /* Keep it simple and unconditionally trigger send data cleanup and
> @@ -1053,12 +1057,12 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
>                         __mptcp_check_push(subflow->conn, sk);
>                 __mptcp_data_acked(subflow->conn);
>                 mptcp_data_unlock(subflow->conn);
> -               return;
> +               return 1;
>         }
>
>         mptcp_get_options(sk, skb, &mp_opt);
> -       if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
> -               return;
> +       if (!check_fully_established(msk, sk, subflow, skb, &mp_opt, &subflow_is_rst))
> +               return subflow_is_rst ? 0 : 1;
>
>         if (mp_opt.fastclose &&
>             msk->local_key == mp_opt.rcvr_key) {
> @@ -1100,7 +1104,7 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
>         }
>
>         if (!mp_opt.dss)
> -               return;
> +               return 1;
>
>         /* we can't wait for recvmsg() to update the ack_seq, otherwise
>          * monodirectional flows will stuck
> @@ -1119,12 +1123,12 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
>                     schedule_work(&msk->work))
>                         sock_hold(subflow->conn);
>
> -               return;
> +               return 1;
>         }
>
>         mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
>         if (!mpext)
> -               return;
> +               return 1;
>
>         memset(mpext, 0, sizeof(*mpext));
>
> @@ -1153,6 +1157,8 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
>                 if (mpext->csum_reqd)
>                         mpext->csum = mp_opt.csum;
>         }
> +
> +       return 1;
>  }
>
>  static void mptcp_set_rwin(const struct tcp_sock *tp)
> --
> 1.8.3.1
>
>
>

  reply	other threads:[~2021-06-25  8:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-25  8:25 [PATCH mptcp-net v7 0/5] Fix some mptcp syncookie process bugs wujianguo106
2021-06-25  8:25 ` [PATCH mptcp-net v7 1/5] mptcp: fix warning in __skb_flow_dissect() when do syn cookie for subflow join wujianguo106
2021-06-25  8:25 ` [PATCH mptcp-net v7 2/5] mptcp: remove redundant req destruct in subflow_check_req() wujianguo106
2021-06-25  8:25 ` [PATCH mptcp-net v7 3/5] mptcp: fix syncookie process if mptcp can not_accept new subflow wujianguo106
2021-06-25  8:25 ` [PATCH mptcp-net v7 4/5] mptcp: avoid processing packet if a subflow reset wujianguo106
2021-06-25  8:58   ` Geliang Tang [this message]
2021-06-25  9:07   ` Matthieu Baerts
2021-06-25  9:46     ` Jianguo Wu
2021-06-26  1:07       ` Mat Martineau
2021-06-25 10:38   ` Paolo Abeni
2021-06-25 10:45   ` Paolo Abeni
2021-06-26  8:59     ` Jianguo Wu
2021-06-25  8:25 ` [PATCH mptcp-net v7 5/5] selftests: mptcp: fix case multiple subflows limited by server wujianguo106

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