Commit 0397c6d8 authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: keep unaccepted MPC subflow into join list 



This will simplify all operation dealing with subflows
before accept time (e.g. data fin processing, add_addr).

The join list is already flushed by mptcp_stream_accept()
before returning the newly created msk to the user space.

This also fixes an potential bug present into the old code:
conn_list was manipulated without helding the msk lock
in mptcp_stream_accept().

Tested-by: default avatarGeliang Tang <geliangtang@gmail.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8b819a84

net/mptcp/protocol.c

+8 −16
Original line number Diff line number Diff line
@@ -2343,7 +2343,6 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 
	if (sk_is_mptcp(newsk)) {

		struct mptcp_subflow_context *subflow;

		struct sock *new_mptcp_sock;

		struct sock *ssk = newsk;



		subflow = mptcp_subflow_ctx(newsk);

		new_mptcp_sock = subflow->conn;
@@ -2358,22 +2357,8 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 


		/* acquire the 2nd reference for the owning socket */

		sock_hold(new_mptcp_sock);



		local_bh_disable();

		bh_lock_sock(new_mptcp_sock);

		msk = mptcp_sk(new_mptcp_sock);

		msk->first = newsk;



		newsk = new_mptcp_sock;

		mptcp_copy_inaddrs(newsk, ssk);

		list_add(&subflow->node, &msk->conn_list);

		sock_hold(ssk);



		mptcp_rcv_space_init(msk, ssk);

		bh_unlock_sock(new_mptcp_sock);



		__MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);

		local_bh_enable();

		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);

	} else {

		MPTCP_INC_STATS(sock_net(sk),

				MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
@@ -2824,6 +2809,12 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 
	if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {

		struct mptcp_sock *msk = mptcp_sk(newsock->sk);

		struct mptcp_subflow_context *subflow;

		struct sock *newsk = newsock->sk;

		bool slowpath;



		slowpath = lock_sock_fast(newsk);

		mptcp_copy_inaddrs(newsk, msk->first);

		mptcp_rcv_space_init(msk, msk->first);



		/* set ssk->sk_socket of accept()ed flows to mptcp socket.

		 * This is needed so NOSPACE flag can be set from tcp stack.
@@ -2835,6 +2826,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 
			if (!ssk->sk_socket)

				mptcp_sock_graft(ssk, newsock);

		}

		unlock_sock_fast(newsk, slowpath);

	}



	if (inet_csk_listen_poll(ssock->sk))

net/mptcp/protocol.h

+9 −0
Original line number Diff line number Diff line
@@ -403,6 +403,15 @@ mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow) 
	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);

}



static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,

					     struct mptcp_subflow_context *subflow)

{

	sock_hold(mptcp_subflow_tcp_sock(subflow));

	spin_lock_bh(&msk->join_list_lock);

	list_add_tail(&subflow->node, &msk->join_list);

	spin_unlock_bh(&msk->join_list_lock);

}



int mptcp_is_enabled(struct net *net);

unsigned int mptcp_get_add_addr_timeout(struct net *net);

void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,

net/mptcp/subflow.c

+5 −5
Original line number Diff line number Diff line
@@ -578,6 +578,10 @@ create_child: 
			 */

			inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);



			/* link the newly created socket to the msk */

			mptcp_add_pending_subflow(mptcp_sk(new_msk), ctx);

			WRITE_ONCE(mptcp_sk(new_msk)->first, child);



			/* new mpc subflow takes ownership of the newly

			 * created mptcp socket

			 */
@@ -1124,11 +1128,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, 
	if (err && err != -EINPROGRESS)

		goto failed;



	sock_hold(ssk);

	spin_lock_bh(&msk->join_list_lock);

	list_add_tail(&subflow->node, &msk->join_list);

	spin_unlock_bh(&msk->join_list_lock);



	mptcp_add_pending_subflow(msk, subflow);

	return err;



failed:

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