Commit 6719331c authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: trigger msk processing even for OoO data 



This is a prerequisite to allow receiving data from multiple
subflows without re-injection.

Instead of dropping the OoO - "future" data in
subflow_check_data_avail(), call into __mptcp_move_skbs()
and let the msk drop that.

To avoid code duplication factor out the mptcp_subflow_discard_data()
helper.

Note that __mptcp_move_skbs() can now find multiple subflows
with data avail (comprising to-be-discarded data), so must
update the byte counter incrementally.

v1 -> v2:
 - fix checkpatch issues (unsigned -> unsigned int)

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 47bebdf3

net/mptcp/protocol.c

+27 −6
Original line number Diff line number Diff line
@@ -167,7 +167,8 @@ static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk, 
		return true;



	subflow->data_avail = 0;

	return mptcp_subflow_data_available(ssk);

	mptcp_subflow_data_available(ssk);

	return subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;

}



static void mptcp_check_data_fin_ack(struct sock *sk)
@@ -313,11 +314,18 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, 
	struct tcp_sock *tp;

	bool done = false;



	if (!mptcp_subflow_dsn_valid(msk, ssk)) {

		*bytes = 0;

	pr_debug("msk=%p ssk=%p data avail=%d valid=%d empty=%d",

		 msk, ssk, subflow->data_avail,

		 mptcp_subflow_dsn_valid(msk, ssk),

		 !skb_peek(&ssk->sk_receive_queue));

	if (subflow->data_avail == MPTCP_SUBFLOW_OOO_DATA) {

		mptcp_subflow_discard_data(ssk, subflow->map_data_len);

		return false;

	}



	if (!mptcp_subflow_dsn_valid(msk, ssk))

		return false;



	tp = tcp_sk(ssk);

	do {

		u32 map_remaining, offset;
@@ -376,7 +384,7 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, 
		}

	} while (more_data_avail);



	*bytes = moved;

	*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
@@ -415,8 +423,16 @@ static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) 


void mptcp_data_ready(struct sock *sk, struct sock *ssk)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);

	struct mptcp_sock *msk = mptcp_sk(sk);

	bool wake;



	/* move_skbs_to_msk below can legitly clear the data_avail flag,

	 * but we will need later to properly woke the reader, cache its

	 * value

	 */

	wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;

	if (wake)

		set_bit(MPTCP_DATA_READY, &msk->flags);



	if (atomic_read(&sk->sk_rmem_alloc) < READ_ONCE(sk->sk_rcvbuf) &&
@@ -438,6 +454,7 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) 
		move_skbs_to_msk(msk, ssk);

	}

wake:

	if (wake)

		sk->sk_data_ready(sk);

}
@@ -1281,6 +1298,9 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 
		set_bit(MPTCP_DATA_READY, &msk->flags);

	}

out_err:

	pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d",

		 msk, test_bit(MPTCP_DATA_READY, &msk->flags),

		 skb_queue_empty(&sk->sk_receive_queue), copied);

	mptcp_rcv_space_adjust(msk, copied);



	release_sock(sk);
@@ -2308,6 +2328,7 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock, 
	sock_poll_wait(file, sock, wait);



	state = inet_sk_state_load(sk);

	pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);

	if (state == TCP_LISTEN)

		return mptcp_check_readable(msk);

net/mptcp/protocol.h

+8 −1
Original line number Diff line number Diff line
@@ -268,6 +268,12 @@ mptcp_subflow_rsk(const struct request_sock *rsk) 
	return (struct mptcp_subflow_request_sock *)rsk;

}



enum mptcp_data_avail {

	MPTCP_SUBFLOW_NODATA,

	MPTCP_SUBFLOW_DATA_AVAIL,

	MPTCP_SUBFLOW_OOO_DATA

};



/* MPTCP subflow context */

struct mptcp_subflow_context {

	struct	list_head node;/* conn_list of subflows */
@@ -292,10 +298,10 @@ struct mptcp_subflow_context { 
		map_valid : 1,

		mpc_map : 1,

		backup : 1,

		data_avail : 1,

		rx_eof : 1,

		use_64bit_ack : 1, /* Set when we received a 64-bit DSN */

		can_ack : 1;	    /* only after processing the remote a key */

	enum mptcp_data_avail data_avail;

	u32	remote_nonce;

	u64	thmac;

	u32	local_nonce;
@@ -347,6 +353,7 @@ int mptcp_is_enabled(struct net *net); 
void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,

				     struct mptcp_options_received *mp_opt);

bool mptcp_subflow_data_available(struct sock *sk);

int mptcp_subflow_discard_data(struct sock *sk, unsigned int limit);

void __init mptcp_subflow_init(void);



/* called with sk socket lock held */

net/mptcp/subflow.c

+43 −35
Original line number Diff line number Diff line
@@ -816,6 +816,40 @@ static int subflow_read_actor(read_descriptor_t *desc, 
	return copy_len;

}



int mptcp_subflow_discard_data(struct sock *ssk, unsigned int limit)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);

	u32 map_remaining;

	size_t delta;



	map_remaining = subflow->map_data_len -

			mptcp_subflow_get_map_offset(subflow);

	delta = min_t(size_t, limit, map_remaining);



	/* discard mapped data */

	pr_debug("discarding %zu bytes, current map len=%d", delta,

		 map_remaining);

	if (delta) {

		read_descriptor_t desc = {

			.count = delta,

		};

		int ret;



		ret = tcp_read_sock(ssk, &desc, subflow_read_actor);

		if (ret < 0) {

			ssk->sk_err = -ret;

			return ret;

		}

		if (ret < delta)

			return 0;

		if (delta == map_remaining) {

			subflow->data_avail = 0;

			subflow->map_valid = 0;

		}

	}

	return 0;

}



static bool subflow_check_data_avail(struct sock *ssk)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
@@ -832,8 +866,6 @@ static bool subflow_check_data_avail(struct sock *ssk) 


	msk = mptcp_sk(subflow->conn);

	for (;;) {

		u32 map_remaining;

		size_t delta;

		u64 ack_seq;

		u64 old_ack;
@@ -851,7 +883,7 @@ static bool subflow_check_data_avail(struct sock *ssk) 
			subflow->map_data_len = skb->len;

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

						   subflow->ssn_offset;

			subflow->data_avail = 1;

			subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;

			return true;

		}
@@ -880,43 +912,19 @@ static bool subflow_check_data_avail(struct sock *ssk) 
		pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,

			 ack_seq);

		if (ack_seq == old_ack) {

			subflow->data_avail = 1;

			subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;

			break;

		} else if (after64(ack_seq, old_ack)) {

			subflow->data_avail = MPTCP_SUBFLOW_OOO_DATA;

			break;

		}



		/* only accept in-sequence mapping. Old values are spurious

		 * retransmission; we can hit "future" values on active backup

		 * subflow switch, we relay on retransmissions to get

		 * in-sequence data.

		 * Cuncurrent subflows support will require subflow data

		 * reordering

		 * retransmission

		 */

		map_remaining = subflow->map_data_len -

				mptcp_subflow_get_map_offset(subflow);

		if (before64(ack_seq, old_ack))

			delta = min_t(size_t, old_ack - ack_seq, map_remaining);

		else

			delta = min_t(size_t, ack_seq - old_ack, map_remaining);



		/* discard mapped data */

		pr_debug("discarding %zu bytes, current map len=%d", delta,

			 map_remaining);

		if (delta) {

			read_descriptor_t desc = {

				.count = delta,

			};

			int ret;



			ret = tcp_read_sock(ssk, &desc, subflow_read_actor);

			if (ret < 0) {

				ssk->sk_err = -ret;

		if (mptcp_subflow_discard_data(ssk, old_ack - ack_seq))

			goto fatal;

			}

			if (ret < delta)

		return false;

			if (delta == map_remaining)

				subflow->map_valid = 0;

		}

	}

	return true;

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