1 files changed, 582 insertions, 271 deletions

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c0abe738e7d3..8c1d1a595701 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -16,6 +16,7 @@
 #include <net/inet_hashtables.h>
 #include <net/protocol.h>
 #include <net/tcp.h>
+#include <net/tcp_states.h>
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 #include <net/transp_v6.h>
 #endif
@@ -52,18 +53,10 @@ static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
 	return msk->subflow;
 }
 
-static bool __mptcp_needs_tcp_fallback(const struct mptcp_sock *msk)
-{
-	return msk->first && !sk_is_mptcp(msk->first);
-}
-
-static struct socket *mptcp_is_tcpsk(struct sock *sk)
+static bool mptcp_is_tcpsk(struct sock *sk)
 {
 	struct socket *sock = sk->sk_socket;
 
-	if (sock->sk != sk)
-		return NULL;
-
 	if (unlikely(sk->sk_prot == &tcp_prot)) {
 		/* we are being invoked after mptcp_accept() has
 		 * accepted a non-mp-capable flow: sk is a tcp_sk,
@@ -73,59 +66,37 @@ static struct socket *mptcp_is_tcpsk(struct sock *sk)
 		 * bypass mptcp.
 		 */
 		sock->ops = &inet_stream_ops;
-		return sock;
+		return true;
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 	} else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
 		sock->ops = &inet6_stream_ops;
-		return sock;
+		return true;
 #endif
 	}
 
-	return NULL;
+	return false;
 }
 
-static struct socket *__mptcp_tcp_fallback(struct mptcp_sock *msk)
+static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
 {
-	struct socket *sock;
-
 	sock_owned_by_me((const struct sock *)msk);
 
-	sock = mptcp_is_tcpsk((struct sock *)msk);
-	if (unlikely(sock))
-		return sock;
-
-	if (likely(!__mptcp_needs_tcp_fallback(msk)))
+	if (likely(!__mptcp_check_fallback(msk)))
 		return NULL;
 
-	return msk->subflow;
-}
-
-static bool __mptcp_can_create_subflow(const struct mptcp_sock *msk)
-{
-	return !msk->first;
+	return msk->first;
 }
 
-static struct socket *__mptcp_socket_create(struct mptcp_sock *msk, int state)
+static int __mptcp_socket_create(struct mptcp_sock *msk)
 {
 	struct mptcp_subflow_context *subflow;
 	struct sock *sk = (struct sock *)msk;
 	struct socket *ssock;
 	int err;
 
-	ssock = __mptcp_tcp_fallback(msk);
-	if (unlikely(ssock))
-		return ssock;
-
-	ssock = __mptcp_nmpc_socket(msk);
-	if (ssock)
-		goto set_state;
-
-	if (!__mptcp_can_create_subflow(msk))
-		return ERR_PTR(-EINVAL);
-
 	err = mptcp_subflow_create_socket(sk, &ssock);
 	if (err)
-		return ERR_PTR(err);
+		return err;
 
 	msk->first = ssock->sk;
 	msk->subflow = ssock;
@@ -133,10 +104,12 @@ static struct socket *__mptcp_socket_create(struct mptcp_sock *msk, int state)
 	list_add(&subflow->node, &msk->conn_list);
 	subflow->request_mptcp = 1;
 
-set_state:
-	if (state != MPTCP_SAME_STATE)
-		inet_sk_state_store(sk, state);
-	return ssock;
+	/* accept() will wait on first subflow sk_wq, and we always wakes up
+	 * via msk->sk_socket
+	 */
+	RCU_INIT_POINTER(msk->first->sk_wq, &sk->sk_socket->wq);
+
+	return 0;
 }
 
 static void __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
@@ -170,6 +143,14 @@ static void __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
 	MPTCP_SKB_CB(skb)->offset = offset;
 }
 
+static void mptcp_stop_timer(struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
+	mptcp_sk(sk)->timer_ival = 0;
+}
+
 /* both sockets must be locked */
 static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk,
 				    struct sock *ssk)
@@ -191,6 +172,139 @@ static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk,
 	return mptcp_subflow_data_available(ssk);
 }
 
+static void mptcp_check_data_fin_ack(struct sock *sk)
+{
+	struct mptcp_sock *msk = mptcp_sk(sk);
+
+	if (__mptcp_check_fallback(msk))
+		return;
+
+	/* Look for an acknowledged DATA_FIN */
+	if (((1 << sk->sk_state) &
+	     (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
+	    msk->write_seq == atomic64_read(&msk->snd_una)) {
+		mptcp_stop_timer(sk);
+
+		WRITE_ONCE(msk->snd_data_fin_enable, 0);
+
+		switch (sk->sk_state) {
+		case TCP_FIN_WAIT1:
+			inet_sk_state_store(sk, TCP_FIN_WAIT2);
+			sk->sk_state_change(sk);
+			break;
+		case TCP_CLOSING:
+			fallthrough;
+		case TCP_LAST_ACK:
+			inet_sk_state_store(sk, TCP_CLOSE);
+			sk->sk_state_change(sk);
+			break;
+		}
+
+		if (sk->sk_shutdown == SHUTDOWN_MASK ||
+		    sk->sk_state == TCP_CLOSE)
+			sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+		else
+			sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+	}
+}
+
+static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
+{
+	struct mptcp_sock *msk = mptcp_sk(sk);
+
+	if (READ_ONCE(msk->rcv_data_fin) &&
+	    ((1 << sk->sk_state) &
+	     (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
+		u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
+
+		if (msk->ack_seq == rcv_data_fin_seq) {
+			if (seq)
+				*seq = rcv_data_fin_seq;
+
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
+{
+	long tout = ssk && inet_csk(ssk)->icsk_pending ?
+				      inet_csk(ssk)->icsk_timeout - jiffies : 0;
+
+	if (tout <= 0)
+		tout = mptcp_sk(sk)->timer_ival;
+	mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
+}
+
+static void mptcp_check_data_fin(struct sock *sk)
+{
+	struct mptcp_sock *msk = mptcp_sk(sk);
+	u64 rcv_data_fin_seq;
+
+	if (__mptcp_check_fallback(msk) || !msk->first)
+		return;
+
+	/* Need to ack a DATA_FIN received from a peer while this side
+	 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
+	 * msk->rcv_data_fin was set when parsing the incoming options
+	 * at the subflow level and the msk lock was not held, so this
+	 * is the first opportunity to act on the DATA_FIN and change
+	 * the msk state.
+	 *
+	 * If we are caught up to the sequence number of the incoming
+	 * DATA_FIN, send the DATA_ACK now and do state transition.  If
+	 * not caught up, do nothing and let the recv code send DATA_ACK
+	 * when catching up.
+	 */
+
+	if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
+		struct mptcp_subflow_context *subflow;
+
+		msk->ack_seq++;
+		WRITE_ONCE(msk->rcv_data_fin, 0);
+
+		sk->sk_shutdown |= RCV_SHUTDOWN;
+		smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+		set_bit(MPTCP_DATA_READY, &msk->flags);
+
+		switch (sk->sk_state) {
+		case TCP_ESTABLISHED:
+			inet_sk_state_store(sk, TCP_CLOSE_WAIT);
+			break;
+		case TCP_FIN_WAIT1:
+			inet_sk_state_store(sk, TCP_CLOSING);
+			break;
+		case TCP_FIN_WAIT2:
+			inet_sk_state_store(sk, TCP_CLOSE);
+			// @@ Close subflows now?
+			break;
+		default:
+			/* Other states not expected */
+			WARN_ON_ONCE(1);
+			break;
+		}
+
+		mptcp_set_timeout(sk, NULL);
+		mptcp_for_each_subflow(msk, subflow) {
+			struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+			lock_sock(ssk);
+			tcp_send_ack(ssk);
+			release_sock(ssk);
+		}
+
+		sk->sk_state_change(sk);
+
+		if (sk->sk_shutdown == SHUTDOWN_MASK ||
+		    sk->sk_state == TCP_CLOSE)
+			sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+		else
+			sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+	}
+}
+
 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 					   struct sock *ssk,
 					   unsigned int *bytes)
@@ -207,13 +321,6 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 		return false;
 	}
 
-	if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
-		int rcvbuf = max(ssk->sk_rcvbuf, sk->sk_rcvbuf);
-
-		if (rcvbuf > sk->sk_rcvbuf)
-			sk->sk_rcvbuf = rcvbuf;
-	}
-
 	tp = tcp_sk(ssk);
 	do {
 		u32 map_remaining, offset;
@@ -229,6 +336,15 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 		if (!skb)
 			break;
 
+		if (__mptcp_check_fallback(msk)) {
+			/* if we are running under the workqueue, TCP could have
+			 * collapsed skbs between dummy map creation and now
+			 * be sure to adjust the size
+			 */
+			map_remaining = skb->len;
+			subflow->map_data_len = skb->len;
+		}
+
 		offset = seq - TCP_SKB_CB(skb)->seq;
 		fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
 		if (fin) {
@@ -265,6 +381,15 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 
 	*bytes = moved;
 
+	/* If the moves have caught up with the DATA_FIN sequence number
+	 * it's time to ack the DATA_FIN and change socket state, but
+	 * this is not a good place to change state. Let the workqueue
+	 * do it.
+	 */
+	if (mptcp_pending_data_fin(sk, NULL) &&
+	    schedule_work(&msk->work))
+		sock_hold(sk);
+
 	return done;
 }
 
@@ -329,16 +454,6 @@ static void __mptcp_flush_join_list(struct mptcp_sock *msk)
 	spin_unlock_bh(&msk->join_list_lock);
 }
 
-static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
-{
-	long tout = ssk && inet_csk(ssk)->icsk_pending ?
-				      inet_csk(ssk)->icsk_timeout - jiffies : 0;
-
-	if (tout <= 0)
-		tout = mptcp_sk(sk)->timer_ival;
-	mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
-}
-
 static bool mptcp_timer_pending(struct sock *sk)
 {
 	return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
@@ -360,7 +475,8 @@ void mptcp_data_acked(struct sock *sk)
 {
 	mptcp_reset_timer(sk);
 
-	if (!sk_stream_is_writeable(sk) &&
+	if ((!sk_stream_is_writeable(sk) ||
+	     (inet_sk_state_load(sk) != TCP_ESTABLISHED)) &&
 	    schedule_work(&mptcp_sk(sk)->work))
 		sock_hold(sk);
 }
@@ -395,14 +511,6 @@ static void mptcp_check_for_eof(struct mptcp_sock *msk)
 	}
 }
 
-static void mptcp_stop_timer(struct sock *sk)
-{
-	struct inet_connection_sock *icsk = inet_csk(sk);
-
-	sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
-	mptcp_sk(sk)->timer_ival = 0;
-}
-
 static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
 {
 	const struct sock *sk = (const struct sock *)msk;
@@ -466,8 +574,15 @@ static void mptcp_clean_una(struct sock *sk)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_data_frag *dtmp, *dfrag;
-	u64 snd_una = atomic64_read(&msk->snd_una);
 	bool cleaned = false;
+	u64 snd_una;
+
+	/* on fallback we just need to ignore snd_una, as this is really
+	 * plain TCP
+	 */
+	if (__mptcp_check_fallback(msk))
+		atomic64_set(&msk->snd_una, msk->write_seq);
+	snd_una = atomic64_read(&msk->snd_una);
 
 	list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
 		if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
@@ -479,15 +594,20 @@ static void mptcp_clean_una(struct sock *sk)
 
 	dfrag = mptcp_rtx_head(sk);
 	if (dfrag && after64(snd_una, dfrag->data_seq)) {
-		u64 delta = dfrag->data_seq + dfrag->data_len - snd_una;
+		u64 delta = snd_una - dfrag->data_seq;
+
+		if (WARN_ON_ONCE(delta > dfrag->data_len))
+			goto out;
 
 		dfrag->data_seq += delta;
+		dfrag->offset += delta;
 		dfrag->data_len -= delta;
 
 		dfrag_uncharge(sk, delta);
 		cleaned = true;
 	}
 
+out:
 	if (cleaned) {
 		sk_mem_reclaim_partial(sk);
 
@@ -673,7 +793,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 out:
 	if (!retransmission)
 		pfrag->offset += frag_truesize;
-	*write_seq += ret;
+	WRITE_ONCE(*write_seq, *write_seq + ret);
 	mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
 
 	return ret;
@@ -740,7 +860,6 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	int mss_now = 0, size_goal = 0, ret = 0;
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct page_frag *pfrag;
-	struct socket *ssock;
 	size_t copied = 0;
 	struct sock *ssk;
 	bool tx_ok;
@@ -759,19 +878,15 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 			goto out;
 	}
 
-fallback:
-	ssock = __mptcp_tcp_fallback(msk);
-	if (unlikely(ssock)) {
-		release_sock(sk);
-		pr_debug("fallback passthrough");
-		ret = sock_sendmsg(ssock, msg);
-		return ret >= 0 ? ret + copied : (copied ? copied : ret);
-	}
-
 	pfrag = sk_page_frag(sk);
 restart:
 	mptcp_clean_una(sk);
 
+	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
+		ret = -EPIPE;
+		goto out;
+	}
+
 wait_for_sndbuf:
 	__mptcp_flush_join_list(msk);
 	ssk = mptcp_subflow_get_send(msk);
@@ -819,17 +934,6 @@ wait_for_sndbuf:
 			}
 			break;
 		}
-		if (ret == 0 && unlikely(__mptcp_needs_tcp_fallback(msk))) {
-			/* Can happen for passive sockets:
-			 * 3WHS negotiated MPTCP, but first packet after is
-			 * plain TCP (e.g. due to middlebox filtering unknown
-			 * options).
-			 *
-			 * Fall back to TCP.
-			 */
-			release_sock(ssk);
-			goto fallback;
-		}
 
 		copied += ret;
 
@@ -880,7 +984,6 @@ wait_for_sndbuf:
 
 	mptcp_set_timeout(sk, ssk);
 	if (copied) {
-		ret = copied;
 		tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,
 			 size_goal);
 
@@ -893,7 +996,7 @@ wait_for_sndbuf:
 	release_sock(ssk);
 out:
 	release_sock(sk);
-	return ret;
+	return copied ? : ret;
 }
 
 static void mptcp_wait_data(struct sock *sk, long *timeo)
@@ -949,6 +1052,100 @@ static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
 	return copied;
 }
 
+/* receive buffer autotuning.  See tcp_rcv_space_adjust for more information.
+ *
+ * Only difference: Use highest rtt estimate of the subflows in use.
+ */
+static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
+{
+	struct mptcp_subflow_context *subflow;
+	struct sock *sk = (struct sock *)msk;
+	u32 time, advmss = 1;
+	u64 rtt_us, mstamp;
+
+	sock_owned_by_me(sk);
+
+	if (copied <= 0)
+		return;
+
+	msk->rcvq_space.copied += copied;
+
+	mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
+	time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
+
+	rtt_us = msk->rcvq_space.rtt_us;
+	if (rtt_us && time < (rtt_us >> 3))
+		return;
+
+	rtt_us = 0;
+	mptcp_for_each_subflow(msk, subflow) {
+		const struct tcp_sock *tp;
+		u64 sf_rtt_us;
+		u32 sf_advmss;
+
+		tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
+
+		sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
+		sf_advmss = READ_ONCE(tp->advmss);
+
+		rtt_us = max(sf_rtt_us, rtt_us);
+		advmss = max(sf_advmss, advmss);
+	}
+
+	msk->rcvq_space.rtt_us = rtt_us;
+	if (time < (rtt_us >> 3) || rtt_us == 0)
+		return;
+
+	if (msk->rcvq_space.copied <= msk->rcvq_space.space)
+		goto new_measure;
+
+	if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
+	    !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
+		int rcvmem, rcvbuf;
+		u64 rcvwin, grow;
+
+		rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
+
+		grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
+
+		do_div(grow, msk->rcvq_space.space);
+		rcvwin += (grow << 1);
+
+		rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
+		while (tcp_win_from_space(sk, rcvmem) < advmss)
+			rcvmem += 128;
+
+		do_div(rcvwin, advmss);
+		rcvbuf = min_t(u64, rcvwin * rcvmem,
+			       sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
+
+		if (rcvbuf > sk->sk_rcvbuf) {
+			u32 window_clamp;
+
+			window_clamp = tcp_win_from_space(sk, rcvbuf);
+			WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
+
+			/* Make subflows follow along.  If we do not do this, we
+			 * get drops at subflow level if skbs can't be moved to
+			 * the mptcp rx queue fast enough (announced rcv_win can
+			 * exceed ssk->sk_rcvbuf).
+			 */
+			mptcp_for_each_subflow(msk, subflow) {
+				struct sock *ssk;
+
+				ssk = mptcp_subflow_tcp_sock(subflow);
+				WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
+				tcp_sk(ssk)->window_clamp = window_clamp;
+			}
+		}
+	}
+
+	msk->rcvq_space.space = msk->rcvq_space.copied;
+new_measure:
+	msk->rcvq_space.copied = 0;
+	msk->rcvq_space.time = mstamp;
+}
+
 static bool __mptcp_move_skbs(struct mptcp_sock *msk)
 {
 	unsigned int moved = 0;
@@ -972,7 +1169,6 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 			 int nonblock, int flags, int *addr_len)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
-	struct socket *ssock;
 	int copied = 0;
 	int target;
 	long timeo;
@@ -981,16 +1177,6 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		return -EOPNOTSUPP;
 
 	lock_sock(sk);
-	ssock = __mptcp_tcp_fallback(msk);
-	if (unlikely(ssock)) {
-fallback:
-		release_sock(sk);
-		pr_debug("fallback-read subflow=%p",
-			 mptcp_subflow_ctx(ssock->sk));
-		copied = sock_recvmsg(ssock, msg, flags);
-		return copied;
-	}
-
 	timeo = sock_rcvtimeo(sk, nonblock);
 
 	len = min_t(size_t, len, INT_MAX);
@@ -1056,9 +1242,6 @@ fallback:
 
 		pr_debug("block timeout %ld", timeo);
 		mptcp_wait_data(sk, &timeo);
-		ssock = __mptcp_tcp_fallback(msk);
-		if (unlikely(ssock))
-			goto fallback;
 	}
 
 	if (skb_queue_empty(&sk->sk_receive_queue)) {
@@ -1075,6 +1258,8 @@ fallback:
 		set_bit(MPTCP_DATA_READY, &msk->flags);
 	}
 out_err:
+	mptcp_rcv_space_adjust(msk, copied);
+
 	release_sock(sk);
 	return copied;
 }
@@ -1083,7 +1268,7 @@ static void mptcp_retransmit_handler(struct sock *sk)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
-	if (atomic64_read(&msk->snd_una) == msk->write_seq) {
+	if (atomic64_read(&msk->snd_una) == READ_ONCE(msk->write_seq)) {
 		mptcp_stop_timer(sk);
 	} else {
 		set_bit(MPTCP_WORK_RTX, &msk->flags);
@@ -1172,6 +1357,29 @@ static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
 	return 0;
 }
 
+static void pm_work(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_data *pm = &msk->pm;
+
+	spin_lock_bh(&msk->pm.lock);
+
+	pr_debug("msk=%p status=%x", msk, pm->status);
+	if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
+		pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
+		mptcp_pm_nl_add_addr_received(msk);
+	}
+	if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
+		pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
+		mptcp_pm_nl_fully_established(msk);
+	}
+	if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
+		pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
+		mptcp_pm_nl_subflow_established(msk);
+	}
+
+	spin_unlock_bh(&msk->pm.lock);
+}
+
 static void mptcp_worker(struct work_struct *work)
 {
 	struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
@@ -1185,12 +1393,18 @@ static void mptcp_worker(struct work_struct *work)
 
 	lock_sock(sk);
 	mptcp_clean_una(sk);
+	mptcp_check_data_fin_ack(sk);
 	__mptcp_flush_join_list(msk);
 	__mptcp_move_skbs(msk);
 
+	if (msk->pm.status)
+		pm_work(msk);
+
 	if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
 		mptcp_check_for_eof(msk);
 
+	mptcp_check_data_fin(sk);
+
 	if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
 		goto unlock;
 
@@ -1283,7 +1497,12 @@ static int mptcp_init_sock(struct sock *sk)
 	if (ret)
 		return ret;
 
+	ret = __mptcp_socket_create(mptcp_sk(sk));
+	if (ret)
+		return ret;
+
 	sk_sockets_allocated_inc(sk);
+	sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
 	sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[2];
 
 	return 0;
@@ -1308,8 +1527,7 @@ static void mptcp_cancel_work(struct sock *sk)
 		sock_put(sk);
 }
 
-static void mptcp_subflow_shutdown(struct sock *ssk, int how,
-				   bool data_fin_tx_enable, u64 data_fin_tx_seq)
+static void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
 {
 	lock_sock(ssk);
 
@@ -1322,36 +1540,84 @@ static void mptcp_subflow_shutdown(struct sock *ssk, int how,
 		tcp_disconnect(ssk, O_NONBLOCK);
 		break;
 	default:
-		if (data_fin_tx_enable) {
-			struct mptcp_subflow_context *subflow;
-
-			subflow = mptcp_subflow_ctx(ssk);
-			subflow->data_fin_tx_seq = data_fin_tx_seq;
-			subflow->data_fin_tx_enable = 1;
+		if (__mptcp_check_fallback(mptcp_sk(sk))) {
+			pr_debug("Fallback");
+			ssk->sk_shutdown |= how;
+			tcp_shutdown(ssk, how);
+		} else {
+			pr_debug("Sending DATA_FIN on subflow %p", ssk);
+			mptcp_set_timeout(sk, ssk);
+			tcp_send_ack(ssk);
 		}
-
-		ssk->sk_shutdown |= how;
-		tcp_shutdown(ssk, how);
 		break;
 	}
 
-	/* Wake up anyone sleeping in poll. */
-	ssk->sk_state_change(ssk);
 	release_sock(ssk);
 }
 
-/* Called with msk lock held, releases such lock before returning */
+static const unsigned char new_state[16] = {
+	/* current state:     new state:      action:	*/
+	[0 /* (Invalid) */] = TCP_CLOSE,
+	[TCP_ESTABLISHED]   = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
+	[TCP_SYN_SENT]      = TCP_CLOSE,
+	[TCP_SYN_RECV]      = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
+	[TCP_FIN_WAIT1]     = TCP_FIN_WAIT1,
+	[TCP_FIN_WAIT2]     = TCP_FIN_WAIT2,
+	[TCP_TIME_WAIT]     = TCP_CLOSE,	/* should not happen ! */
+	[TCP_CLOSE]         = TCP_CLOSE,
+	[TCP_CLOSE_WAIT]    = TCP_LAST_ACK  | TCP_ACTION_FIN,
+	[TCP_LAST_ACK]      = TCP_LAST_ACK,
+	[TCP_LISTEN]        = TCP_CLOSE,
+	[TCP_CLOSING]       = TCP_CLOSING,
+	[TCP_NEW_SYN_RECV]  = TCP_CLOSE,	/* should not happen ! */
+};
+
+static int mptcp_close_state(struct sock *sk)
+{
+	int next = (int)new_state[sk->sk_state];
+	int ns = next & TCP_STATE_MASK;
+
+	inet_sk_state_store(sk, ns);
+
+	return next & TCP_ACTION_FIN;
+}
+
 static void mptcp_close(struct sock *sk, long timeout)
 {
 	struct mptcp_subflow_context *subflow, *tmp;
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	LIST_HEAD(conn_list);
-	u64 data_fin_tx_seq;
 
 	lock_sock(sk);
+	sk->sk_shutdown = SHUTDOWN_MASK;
+
+	if (sk->sk_state == TCP_LISTEN) {
+		inet_sk_state_store(sk, TCP_CLOSE);
+		goto cleanup;
+	} else if (sk->sk_state == TCP_CLOSE) {
+		goto cleanup;
+	}
+
+	if (__mptcp_check_fallback(msk)) {
+		goto update_state;
+	} else if (mptcp_close_state(sk)) {
+		pr_debug("Sending DATA_FIN sk=%p", sk);
+		WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
+		WRITE_ONCE(msk->snd_data_fin_enable, 1);
+
+		mptcp_for_each_subflow(msk, subflow) {
+			struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+			mptcp_subflow_shutdown(sk, tcp_sk, SHUTDOWN_MASK);
+		}
+	}
+
+	sk_stream_wait_close(sk, timeout);
 
+update_state:
 	inet_sk_state_store(sk, TCP_CLOSE);
 
+cleanup:
 	/* be sure to always acquire the join list lock, to sync vs
 	 * mptcp_finish_join().
 	 */
@@ -1360,22 +1626,16 @@ static void mptcp_close(struct sock *sk, long timeout)
 	spin_unlock_bh(&msk->join_list_lock);
 	list_splice_init(&msk->conn_list, &conn_list);
 
-	data_fin_tx_seq = msk->write_seq;
-
 	__mptcp_clear_xmit(sk);
 
 	release_sock(sk);
 
 	list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-
-		subflow->data_fin_tx_seq = data_fin_tx_seq;
-		subflow->data_fin_tx_enable = 1;
 		__mptcp_close_ssk(sk, ssk, subflow, timeout);
 	}
 
 	mptcp_cancel_work(sk);
-	mptcp_pm_close(msk);
 
 	__skb_queue_purge(&sk->sk_receive_queue);
 
@@ -1447,20 +1707,7 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
 	msk->local_key = subflow_req->local_key;
 	msk->token = subflow_req->token;
 	msk->subflow = NULL;
-
-	if (unlikely(mptcp_token_new_accept(subflow_req->token, nsk))) {
-		nsk->sk_state = TCP_CLOSE;
-		bh_unlock_sock(nsk);
-
-		/* we can't call into mptcp_close() here - possible BH context
-		 * free the sock directly.
-		 * sk_clone_lock() sets nsk refcnt to two, hence call sk_free()
-		 * too.
-		 */
-		sk_common_release(nsk);
-		sk_free(nsk);
-		return NULL;
-	}
+	WRITE_ONCE(msk->fully_established, false);
 
 	msk->write_seq = subflow_req->idsn + 1;
 	atomic64_set(&msk->snd_una, msk->write_seq);
@@ -1482,6 +1729,22 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
 	return nsk;
 }
 
+void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
+{
+	const struct tcp_sock *tp = tcp_sk(ssk);
+
+	msk->rcvq_space.copied = 0;
+	msk->rcvq_space.rtt_us = 0;
+
+	msk->rcvq_space.time = tp->tcp_mstamp;
+
+	/* initial rcv_space offering made to peer */
+	msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
+				      TCP_INIT_CWND * tp->advmss);
+	if (msk->rcvq_space.space == 0)
+		msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
+}
+
 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
 				 bool kern)
 {
@@ -1501,7 +1764,6 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
 		return NULL;
 
 	pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
-
 	if (sk_is_mptcp(newsk)) {
 		struct mptcp_subflow_context *subflow;
 		struct sock *new_mptcp_sock;
@@ -1529,8 +1791,8 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
 		newsk = new_mptcp_sock;
 		mptcp_copy_inaddrs(newsk, ssk);
 		list_add(&subflow->node, &msk->conn_list);
-		inet_sk_state_store(newsk, TCP_ESTABLISHED);
 
+		mptcp_rcv_space_init(msk, ssk);
 		bh_unlock_sock(new_mptcp_sock);
 
 		__MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
@@ -1547,21 +1809,82 @@ static void mptcp_destroy(struct sock *sk)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
-	mptcp_token_destroy(msk->token);
+	mptcp_token_destroy(msk);
 	if (msk->cached_ext)
 		__skb_ext_put(msk->cached_ext);
 
 	sk_sockets_allocated_dec(sk);
 }
 
+static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
+				       sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = (struct sock *)msk;
+	struct socket *ssock;
+	int ret;
+
+	switch (optname) {
+	case SO_REUSEPORT:
+	case SO_REUSEADDR:
+		lock_sock(sk);
+		ssock = __mptcp_nmpc_socket(msk);
+		if (!ssock) {
+			release_sock(sk);
+			return -EINVAL;
+		}
+
+		ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
+		if (ret == 0) {
+			if (optname == SO_REUSEPORT)
+				sk->sk_reuseport = ssock->sk->sk_reuseport;
+			else if (optname == SO_REUSEADDR)
+				sk->sk_reuse = ssock->sk->sk_reuse;
+		}
+		release_sock(sk);
+		return ret;
+	}
+
+	return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
+}
+
+static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
+			       sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = (struct sock *)msk;
+	int ret = -EOPNOTSUPP;
+	struct socket *ssock;
+
+	switch (optname) {
+	case IPV6_V6ONLY:
+		lock_sock(sk);
+		ssock = __mptcp_nmpc_socket(msk);
+		if (!ssock) {
+			release_sock(sk);
+			return -EINVAL;
+		}
+
+		ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
+		if (ret == 0)
+			sk->sk_ipv6only = ssock->sk->sk_ipv6only;
+
+		release_sock(sk);
+		break;
+	}
+
+	return ret;
+}
+
 static int mptcp_setsockopt(struct sock *sk, int level, int optname,
-			    char __user *optval, unsigned int optlen)
+			    sockptr_t optval, unsigned int optlen)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
-	struct socket *ssock;
+	struct sock *ssk;
 
 	pr_debug("msk=%p", msk);
 
+	if (level == SOL_SOCKET)
+		return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
+
 	/* @@ the meaning of setsockopt() when the socket is connected and
 	 * there are multiple subflows is not yet defined. It is up to the
 	 * MPTCP-level socket to configure the subflows until the subflow
@@ -1569,11 +1892,13 @@ static int mptcp_setsockopt(struct sock *sk, int level, int optname,
 	 * to the one remaining subflow.
 	 */
 	lock_sock(sk);
-	ssock = __mptcp_tcp_fallback(msk);
+	ssk = __mptcp_tcp_fallback(msk);
 	release_sock(sk);
-	if (ssock)
-		return tcp_setsockopt(ssock->sk, level, optname, optval,
-				      optlen);
+	if (ssk)
+		return tcp_setsockopt(ssk, level, optname, optval, optlen);
+
+	if (level == SOL_IPV6)
+		return mptcp_setsockopt_v6(msk, optname, optval, optlen);
 
 	return -EOPNOTSUPP;
 }
@@ -1582,7 +1907,7 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname,
 			    char __user *optval, int __user *option)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
-	struct socket *ssock;
+	struct sock *ssk;
 
 	pr_debug("msk=%p", msk);
 
@@ -1593,11 +1918,10 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname,
 	 * to the one remaining subflow.
 	 */
 	lock_sock(sk);
-	ssock = __mptcp_tcp_fallback(msk);
+	ssk = __mptcp_tcp_fallback(msk);
 	release_sock(sk);
-	if (ssock)
-		return tcp_getsockopt(ssock->sk, level, optname, optval,
-				      option);
+	if (ssk)
+		return tcp_getsockopt(ssk, level, optname, optval, option);
 
 	return -EOPNOTSUPP;
 }
@@ -1636,6 +1960,20 @@ static void mptcp_release_cb(struct sock *sk)
 	}
 }
 
+static int mptcp_hash(struct sock *sk)
+{
+	/* should never be called,
+	 * we hash the TCP subflows not the master socket
+	 */
+	WARN_ON_ONCE(1);
+	return 0;
+}
+
+static void mptcp_unhash(struct sock *sk)
+{
+	/* called from sk_common_release(), but nothing to do here */
+}
+
 static int mptcp_get_port(struct sock *sk, unsigned short snum)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
@@ -1660,32 +1998,26 @@ void mptcp_finish_connect(struct sock *ssk)
 	sk = subflow->conn;
 	msk = mptcp_sk(sk);
 
-	if (!subflow->mp_capable) {
-		MPTCP_INC_STATS(sock_net(sk),
-				MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
-		return;
-	}
-
 	pr_debug("msk=%p, token=%u", sk, subflow->token);
 
 	mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
 	ack_seq++;
 	subflow->map_seq = ack_seq;
 	subflow->map_subflow_seq = 1;
-	subflow->rel_write_seq = 1;
 
 	/* the socket is not connected yet, no msk/subflow ops can access/race
 	 * accessing the field below
 	 */
 	WRITE_ONCE(msk->remote_key, subflow->remote_key);
 	WRITE_ONCE(msk->local_key, subflow->local_key);
-	WRITE_ONCE(msk->token, subflow->token);
 	WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
 	WRITE_ONCE(msk->ack_seq, ack_seq);
 	WRITE_ONCE(msk->can_ack, 1);
 	atomic64_set(&msk->snd_una, msk->write_seq);
 
 	mptcp_pm_new_connection(msk, 0);
+
+	mptcp_rcv_space_init(msk, ssk);
 }
 
 static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
@@ -1708,7 +2040,7 @@ bool mptcp_finish_join(struct sock *sk)
 	pr_debug("msk=%p, subflow=%p", msk, subflow);
 
 	/* mptcp socket already closing? */
-	if (inet_sk_state_load(parent) != TCP_ESTABLISHED)
+	if (!mptcp_is_fully_established(parent))
 		return false;
 
 	if (!msk->pm.server_side)
@@ -1761,8 +2093,8 @@ static struct proto mptcp_prot = {
 	.sendmsg	= mptcp_sendmsg,
 	.recvmsg	= mptcp_recvmsg,
 	.release_cb	= mptcp_release_cb,
-	.hash		= inet_hash,
-	.unhash		= inet_unhash,
+	.hash		= mptcp_hash,
+	.unhash		= mptcp_unhash,
 	.get_port	= mptcp_get_port,
 	.sockets_allocated	= &mptcp_sockets_allocated,
 	.memory_allocated	= &tcp_memory_allocated,
@@ -1771,6 +2103,7 @@ static struct proto mptcp_prot = {
 	.sysctl_wmem_offset	= offsetof(struct net, ipv4.sysctl_tcp_wmem),
 	.sysctl_mem	= sysctl_tcp_mem,
 	.obj_size	= sizeof(struct mptcp_sock),
+	.slab_flags	= SLAB_TYPESAFE_BY_RCU,
 	.no_autobind	= true,
 };
 
@@ -1781,9 +2114,9 @@ static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	int err;
 
 	lock_sock(sock->sk);
-	ssock = __mptcp_socket_create(msk, MPTCP_SAME_STATE);
-	if (IS_ERR(ssock)) {
-		err = PTR_ERR(ssock);
+	ssock = __mptcp_nmpc_socket(msk);
+	if (!ssock) {
+		err = -EINVAL;
 		goto unlock;
 	}
 
@@ -1796,10 +2129,18 @@ unlock:
 	return err;
 }
 
+static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
+					 struct mptcp_subflow_context *subflow)
+{
+	subflow->request_mptcp = 0;
+	__mptcp_do_fallback(msk);
+}
+
 static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 				int addr_len, int flags)
 {
 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
+	struct mptcp_subflow_context *subflow;
 	struct socket *ssock;
 	int err;
 
@@ -1812,19 +2153,24 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 		goto do_connect;
 	}
 
-	ssock = __mptcp_socket_create(msk, TCP_SYN_SENT);
-	if (IS_ERR(ssock)) {
-		err = PTR_ERR(ssock);
+	ssock = __mptcp_nmpc_socket(msk);
+	if (!ssock) {
+		err = -EINVAL;
 		goto unlock;
 	}
 
+	mptcp_token_destroy(msk);
+	inet_sk_state_store(sock->sk, TCP_SYN_SENT);
+	subflow = mptcp_subflow_ctx(ssock->sk);
 #ifdef CONFIG_TCP_MD5SIG
 	/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
 	 * TCP option space.
 	 */
 	if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
-		mptcp_subflow_ctx(ssock->sk)->request_mptcp = 0;
+		mptcp_subflow_early_fallback(msk, subflow);
 #endif
+	if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk))
+		mptcp_subflow_early_fallback(msk, subflow);
 
 do_connect:
 	err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
@@ -1843,42 +2189,6 @@ unlock:
 	return err;
 }
 
-static int mptcp_v4_getname(struct socket *sock, struct sockaddr *uaddr,
-			    int peer)
-{
-	if (sock->sk->sk_prot == &tcp_prot) {
-		/* we are being invoked from __sys_accept4, after
-		 * mptcp_accept() has just accepted a non-mp-capable
-		 * flow: sk is a tcp_sk, not an mptcp one.
-		 *
-		 * Hand the socket over to tcp so all further socket ops
-		 * bypass mptcp.
-		 */
-		sock->ops = &inet_stream_ops;
-	}
-
-	return inet_getname(sock, uaddr, peer);
-}
-
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-static int mptcp_v6_getname(struct socket *sock, struct sockaddr *uaddr,
-			    int peer)
-{
-	if (sock->sk->sk_prot == &tcpv6_prot) {
-		/* we are being invoked from __sys_accept4 after
-		 * mptcp_accept() has accepted a non-mp-capable
-		 * subflow: sk is a tcp_sk, not mptcp.
-		 *
-		 * Hand the socket over to tcp so all further
-		 * socket ops bypass mptcp.
-		 */
-		sock->ops = &inet6_stream_ops;
-	}
-
-	return inet6_getname(sock, uaddr, peer);
-}
-#endif
-
 static int mptcp_listen(struct socket *sock, int backlog)
 {
 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
@@ -1888,12 +2198,14 @@ static int mptcp_listen(struct socket *sock, int backlog)
 	pr_debug("msk=%p", msk);
 
 	lock_sock(sock->sk);
-	ssock = __mptcp_socket_create(msk, TCP_LISTEN);
-	if (IS_ERR(ssock)) {
-		err = PTR_ERR(ssock);
+	ssock = __mptcp_nmpc_socket(msk);
+	if (!ssock) {
+		err = -EINVAL;
 		goto unlock;
 	}
 
+	mptcp_token_destroy(msk);
+	inet_sk_state_store(sock->sk, TCP_LISTEN);
 	sock_set_flag(sock->sk, SOCK_RCU_FREE);
 
 	err = ssock->ops->listen(ssock, backlog);
@@ -1906,15 +2218,6 @@ unlock:
 	return err;
 }
 
-static bool is_tcp_proto(const struct proto *p)
-{
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-	return p == &tcp_prot || p == &tcpv6_prot;
-#else
-	return p == &tcp_prot;
-#endif
-}
-
 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 			       int flags, bool kern)
 {
@@ -1932,11 +2235,12 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 	if (!ssock)
 		goto unlock_fail;
 
+	clear_bit(MPTCP_DATA_READY, &msk->flags);
 	sock_hold(ssock->sk);
 	release_sock(sock->sk);
 
 	err = ssock->ops->accept(sock, newsock, flags, kern);
-	if (err == 0 && !is_tcp_proto(newsock->sk->sk_prot)) {
+	if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
 		struct mptcp_sock *msk = mptcp_sk(newsock->sk);
 		struct mptcp_subflow_context *subflow;
 
@@ -1944,7 +2248,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 		 * This is needed so NOSPACE flag can be set from tcp stack.
 		 */
 		__mptcp_flush_join_list(msk);
-		list_for_each_entry(subflow, &msk->conn_list, node) {
+		mptcp_for_each_subflow(msk, subflow) {
 			struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 
 			if (!ssk->sk_socket)
@@ -1952,6 +2256,8 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
 		}
 	}
 
+	if (inet_csk_listen_poll(ssock->sk))
+		set_bit(MPTCP_DATA_READY, &msk->flags);
 	sock_put(ssock->sk);
 	return err;
 
@@ -1960,39 +2266,36 @@ unlock_fail:
 	return -EINVAL;
 }
 
+static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
+{
+	return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM :
+	       0;
+}
+
 static __poll_t mptcp_poll(struct file *file, struct socket *sock,
 			   struct poll_table_struct *wait)
 {
 	struct sock *sk = sock->sk;
 	struct mptcp_sock *msk;
-	struct socket *ssock;
 	__poll_t mask = 0;
+	int state;
 
 	msk = mptcp_sk(sk);
-	lock_sock(sk);
-	ssock = __mptcp_tcp_fallback(msk);
-	if (!ssock)
-		ssock = __mptcp_nmpc_socket(msk);
-	if (ssock) {
-		mask = ssock->ops->poll(file, ssock, wait);
-		release_sock(sk);
-		return mask;
-	}
-
-	release_sock(sk);
 	sock_poll_wait(file, sock, wait);
-	lock_sock(sk);
 
-	if (test_bit(MPTCP_DATA_READY, &msk->flags))
-		mask = EPOLLIN | EPOLLRDNORM;
-	if (sk_stream_is_writeable(sk) &&
-	    test_bit(MPTCP_SEND_SPACE, &msk->flags))
-		mask |= EPOLLOUT | EPOLLWRNORM;
+	state = inet_sk_state_load(sk);
+	if (state == TCP_LISTEN)
+		return mptcp_check_readable(msk);
+
+	if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
+		mask |= mptcp_check_readable(msk);
+		if (sk_stream_is_writeable(sk) &&
+		    test_bit(MPTCP_SEND_SPACE, &msk->flags))
+			mask |= EPOLLOUT | EPOLLWRNORM;
+	}
 	if (sk->sk_shutdown & RCV_SHUTDOWN)
 		mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
 
-	release_sock(sk);
-
 	return mask;
 }
 
@@ -2000,23 +2303,13 @@ static int mptcp_shutdown(struct socket *sock, int how)
 {
 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
 	struct mptcp_subflow_context *subflow;
-	struct socket *ssock;
 	int ret = 0;
 
 	pr_debug("sk=%p, how=%d", msk, how);
 
 	lock_sock(sock->sk);
-	ssock = __mptcp_tcp_fallback(msk);
-	if (ssock) {
-		release_sock(sock->sk);
-		return inet_shutdown(ssock, how);
-	}
-
-	if (how == SHUT_WR || how == SHUT_RDWR)
-		inet_sk_state_store(sock->sk, TCP_FIN_WAIT1);
 
 	how++;
-
 	if ((how & ~SHUTDOWN_MASK) || !how) {
 		ret = -EINVAL;
 		goto out_unlock;
@@ -2030,13 +2323,36 @@ static int mptcp_shutdown(struct socket *sock, int how)
 			sock->state = SS_CONNECTED;
 	}
 
-	__mptcp_flush_join_list(msk);
-	mptcp_for_each_subflow(msk, subflow) {
-		struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+	/* If we've already sent a FIN, or it's a closed state, skip this. */
+	if (__mptcp_check_fallback(msk)) {
+		if (how == SHUT_WR || how == SHUT_RDWR)
+			inet_sk_state_store(sock->sk, TCP_FIN_WAIT1);
 
-		mptcp_subflow_shutdown(tcp_sk, how, 1, msk->write_seq);
+		mptcp_for_each_subflow(msk, subflow) {
+			struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+			mptcp_subflow_shutdown(sock->sk, tcp_sk, how);
+		}
+	} else if ((how & SEND_SHUTDOWN) &&
+		   ((1 << sock->sk->sk_state) &
+		    (TCPF_ESTABLISHED | TCPF_SYN_SENT |
+		     TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) &&
+		   mptcp_close_state(sock->sk)) {
+		__mptcp_flush_join_list(msk);
+
+		WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
+		WRITE_ONCE(msk->snd_data_fin_enable, 1);
+
+		mptcp_for_each_subflow(msk, subflow) {
+			struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+			mptcp_subflow_shutdown(sock->sk, tcp_sk, how);
+		}
 	}
 
+	/* Wake up anyone sleeping in poll. */
+	sock->sk->sk_state_change(sock->sk);
+
 out_unlock:
 	release_sock(sock->sk);
 
@@ -2051,7 +2367,7 @@ static const struct proto_ops mptcp_stream_ops = {
 	.connect	   = mptcp_stream_connect,
 	.socketpair	   = sock_no_socketpair,
 	.accept		   = mptcp_stream_accept,
-	.getname	   = mptcp_v4_getname,
+	.getname	   = inet_getname,
 	.poll		   = mptcp_poll,
 	.ioctl		   = inet_ioctl,
 	.gettstamp	   = sock_gettstamp,
@@ -2063,10 +2379,6 @@ static const struct proto_ops mptcp_stream_ops = {
 	.recvmsg	   = inet_recvmsg,
 	.mmap		   = sock_no_mmap,
 	.sendpage	   = inet_sendpage,
-#ifdef CONFIG_COMPAT
-	.compat_setsockopt = compat_sock_common_setsockopt,
-	.compat_getsockopt = compat_sock_common_getsockopt,
-#endif
 };
 
 static struct inet_protosw mptcp_protosw = {
@@ -2077,7 +2389,7 @@ static struct inet_protosw mptcp_protosw = {
 	.flags		= INET_PROTOSW_ICSK,
 };
 
-void mptcp_proto_init(void)
+void __init mptcp_proto_init(void)
 {
 	mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
 
@@ -2086,6 +2398,7 @@ void mptcp_proto_init(void)
 
 	mptcp_subflow_init();
 	mptcp_pm_init();
+	mptcp_token_init();
 
 	if (proto_register(&mptcp_prot, 1) != 0)
 		panic("Failed to register MPTCP proto.\n");
@@ -2104,7 +2417,7 @@ static const struct proto_ops mptcp_v6_stream_ops = {
 	.connect	   = mptcp_stream_connect,
 	.socketpair	   = sock_no_socketpair,
 	.accept		   = mptcp_stream_accept,
-	.getname	   = mptcp_v6_getname,
+	.getname	   = inet6_getname,
 	.poll		   = mptcp_poll,
 	.ioctl		   = inet6_ioctl,
 	.gettstamp	   = sock_gettstamp,
@@ -2118,8 +2431,6 @@ static const struct proto_ops mptcp_v6_stream_ops = {
 	.sendpage	   = inet_sendpage,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	   = inet6_compat_ioctl,
-	.compat_setsockopt = compat_sock_common_setsockopt,
-	.compat_getsockopt = compat_sock_common_getsockopt,
 #endif
 };
 
@@ -2139,7 +2450,7 @@ static struct inet_protosw mptcp_v6_protosw = {
 	.flags		= INET_PROTOSW_ICSK,
 };
 
-int mptcp_proto_v6_init(void)
+int __init mptcp_proto_v6_init(void)
 {
 	int err;