Commit 6850ec97 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'mptcp-fixes-for-5-13' 

Mat Martineau says:

====================
mptcp: Fixes for 5.13

These patches address two issues in MPTCP.

Patch 1 fixes a locking issue affecting MPTCP-level retransmissions.

Patches 2-4 improve handling of out-of-order packet arrival early
in a connection, so it falls back to TCP rather than forcing a
reset. Includes a selftest.
====================

Link: https://lore.kernel.org/r/20210527233140.182728-1-mathew.j.martineau@linux.intel.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 44991d61 69ca3d29

net/mptcp/protocol.c

+15 −1
Original line number Diff line number Diff line
@@ -947,6 +947,10 @@ static void __mptcp_update_wmem(struct sock *sk) 
{

	struct mptcp_sock *msk = mptcp_sk(sk);



#ifdef CONFIG_LOCKDEP

	WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock));

#endif



	if (!msk->wmem_reserved)

		return;
@@ -1085,10 +1089,20 @@ static void __mptcp_clean_una(struct sock *sk) 


static void __mptcp_clean_una_wakeup(struct sock *sk)

{

#ifdef CONFIG_LOCKDEP

	WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock));

#endif

	__mptcp_clean_una(sk);

	mptcp_write_space(sk);

}



static void mptcp_clean_una_wakeup(struct sock *sk)

{

	mptcp_data_lock(sk);

	__mptcp_clean_una_wakeup(sk);

	mptcp_data_unlock(sk);

}



static void mptcp_enter_memory_pressure(struct sock *sk)

{

	struct mptcp_subflow_context *subflow;
@@ -2299,7 +2313,7 @@ static void __mptcp_retrans(struct sock *sk) 
	struct sock *ssk;

	int ret;



	__mptcp_clean_una_wakeup(sk);

	mptcp_clean_una_wakeup(sk);

	dfrag = mptcp_rtx_head(sk);

	if (!dfrag) {

		if (mptcp_data_fin_enabled(msk)) {

net/mptcp/subflow.c

+40 −39
Original line number Diff line number Diff line
@@ -630,21 +630,20 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 


	/* if the sk is MP_CAPABLE, we try to fetch the client key */

	if (subflow_req->mp_capable) {

		if (TCP_SKB_CB(skb)->seq != subflow_req->ssn_offset + 1) {

			/* here we can receive and accept an in-window,

			 * out-of-order pkt, which will not carry the MP_CAPABLE

			 * opt even on mptcp enabled paths

		/* we can receive and accept an in-window, out-of-order pkt,

		 * which may not carry the MP_CAPABLE opt even on mptcp enabled

		 * paths: always try to extract the peer key, and fallback

		 * for packets missing it.

		 * Even OoO DSS packets coming legitly after dropped or

		 * reordered MPC will cause fallback, but we don't have other

		 * options.

		 */

			goto create_msk;

		}



		mptcp_get_options(skb, &mp_opt);

		if (!mp_opt.mp_capable) {

			fallback = true;

			goto create_child;

		}



create_msk:

		new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);

		if (!new_msk)

			fallback = true;
@@ -1012,21 +1011,11 @@ static bool subflow_check_data_avail(struct sock *ssk) 


		status = get_mapping_status(ssk, msk);

		trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue));

		if (status == MAPPING_INVALID) {

			ssk->sk_err = EBADMSG;

			goto fatal;

		}

		if (status == MAPPING_DUMMY) {

			__mptcp_do_fallback(msk);

			skb = skb_peek(&ssk->sk_receive_queue);

			subflow->map_valid = 1;

			subflow->map_seq = READ_ONCE(msk->ack_seq);

			subflow->map_data_len = skb->len;

			subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -

						   subflow->ssn_offset;

			subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;

			return true;

		}

		if (unlikely(status == MAPPING_INVALID))

			goto fallback;



		if (unlikely(status == MAPPING_DUMMY))

			goto fallback;



		if (status != MAPPING_OK)

			goto no_data;
@@ -1039,10 +1028,8 @@ static bool subflow_check_data_avail(struct sock *ssk) 
		 * MP_CAPABLE-based mapping

		 */

		if (unlikely(!READ_ONCE(msk->can_ack))) {

			if (!subflow->mpc_map) {

				ssk->sk_err = EBADMSG;

				goto fatal;

			}

			if (!subflow->mpc_map)

				goto fallback;

			WRITE_ONCE(msk->remote_key, subflow->remote_key);

			WRITE_ONCE(msk->ack_seq, subflow->map_seq);

			WRITE_ONCE(msk->can_ack, true);
@@ -1070,10 +1057,14 @@ static bool subflow_check_data_avail(struct sock *ssk) 
no_data:

	subflow_sched_work_if_closed(msk, ssk);

	return false;

fatal:

	/* fatal protocol error, close the socket */

	/* This barrier is coupled with smp_rmb() in tcp_poll() */

	smp_wmb();



fallback:

	/* RFC 8684 section 3.7. */

	if (subflow->mp_join || subflow->fully_established) {

		/* fatal protocol error, close the socket.

		 * subflow_error_report() will introduce the appropriate barriers

		 */

		ssk->sk_err = EBADMSG;

		ssk->sk_error_report(ssk);

		tcp_set_state(ssk, TCP_CLOSE);

		subflow->reset_transient = 0;
@@ -1083,6 +1074,16 @@ static bool subflow_check_data_avail(struct sock *ssk) 
		return false;

	}



	__mptcp_do_fallback(msk);

	skb = skb_peek(&ssk->sk_receive_queue);

	subflow->map_valid = 1;

	subflow->map_seq = READ_ONCE(msk->ack_seq);

	subflow->map_data_len = skb->len;

	subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;

	subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;

	return true;

}



bool mptcp_subflow_data_available(struct sock *sk)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);

tools/testing/selftests/net/mptcp/mptcp_connect.sh

+9 −4
Original line number Diff line number Diff line
@@ -501,6 +501,7 @@ do_transfer() 
	local stat_ackrx_now_l=$(get_mib_counter "${listener_ns}" "MPTcpExtMPCapableACKRX")

	local stat_cookietx_now=$(get_mib_counter "${listener_ns}" "TcpExtSyncookiesSent")

	local stat_cookierx_now=$(get_mib_counter "${listener_ns}" "TcpExtSyncookiesRecv")

	local stat_ooo_now=$(get_mib_counter "${listener_ns}" "TcpExtTCPOFOQueue")



	expect_synrx=$((stat_synrx_last_l))

	expect_ackrx=$((stat_ackrx_last_l))
@@ -518,10 +519,14 @@ do_transfer() 
			"${stat_synrx_now_l}" "${expect_synrx}" 1>&2

		retc=1

	fi

	if [ ${stat_ackrx_now_l} -lt ${expect_ackrx} ]; then

	if [ ${stat_ackrx_now_l} -lt ${expect_ackrx} -a ${stat_ooo_now} -eq 0 ]; then

		if [ ${stat_ooo_now} -eq 0 ]; then

			printf "[ FAIL ] lower MPC ACK rx (%d) than expected (%d)\n" \

				"${stat_ackrx_now_l}" "${expect_ackrx}" 1>&2

			rets=1

		else

			printf "[ Note ] fallback due to TCP OoO"

		fi

	fi



	if [ $retc -eq 0 ] && [ $rets -eq 0 ]; then