Commit 70c708e8 authored by Kishen Maloor's avatar Kishen Maloor Committed by Jakub Kicinski
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mptcp: establish subflows from either end of connection 



This change updates internal logic to permit subflows to be
established from either the client or server ends of MPTCP
connections. This symmetry and added flexibility may be
harnessed by PM implementations running on either end in
creating new subflows.

The essence of this change lies in not relying on the
"server_side" flag (which continues to be available if needed).

Acked-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarKishen Maloor <kishen.maloor@intel.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d1ace2d9

net/mptcp/options.c

+1 −1
Original line number Diff line number Diff line
@@ -931,7 +931,7 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, 
		if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 &&

		    TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&

		    subflow->mp_join && (mp_opt->suboptions & OPTIONS_MPTCP_MPJ) &&

		    READ_ONCE(msk->pm.server_side))

		    !subflow->request_join)

			tcp_send_ack(ssk);

		goto fully_established;

	}

net/mptcp/protocol.c

+1 −4
Original line number Diff line number Diff line
@@ -3321,15 +3321,12 @@ bool mptcp_finish_join(struct sock *ssk) 
		return false;

	}



	if (!msk->pm.server_side)

	if (!list_empty(&subflow->node))

		goto out;



	if (!mptcp_pm_allow_new_subflow(msk))

		goto err_prohibited;



	if (WARN_ON_ONCE(!list_empty(&subflow->node)))

		goto err_prohibited;



	/* active connections are already on conn_list.

	 * If we can't acquire msk socket lock here, let the release callback

	 * handle it

net/mptcp/protocol.h

+6 −2
Original line number Diff line number Diff line
@@ -911,13 +911,17 @@ static inline bool mptcp_check_infinite_map(struct sk_buff *skb) 
	return false;

}



static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)

{

	return (subflow->request_mptcp || subflow->request_join);

}



static inline bool subflow_simultaneous_connect(struct sock *sk)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);

	struct sock *parent = subflow->conn;



	return sk->sk_state == TCP_ESTABLISHED &&

	       !mptcp_sk(parent)->pm.server_side &&

	       is_active_ssk(subflow) &&

	       !subflow->conn_finished;

}