Commit a29b56c4 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'mptcp-Improve-DATA_FIN-transmission' 



Mat Martineau says:

====================
mptcp: Improve DATA_FIN transmission

MPTCP's DATA_FIN flag is sent in a DSS option when closing the
MPTCP-level connection. This patch series prepares for correct DATA_FIN
handling across multiple subflows (where individual subflows may
disconnect without closing the entire MPTCP connection) by changing the
way the MPTCP-level socket requests a DATA_FIN on a subflow and
propagates the necessary data for the TCP option.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 0a303214 6d37a0b8

net/mptcp/options.c

+8 −8
Original line number Diff line number Diff line
@@ -304,21 +304,22 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, 
static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,

				 struct mptcp_ext *ext)

{

	ext->data_fin = 1;



	if (!ext->use_map) {

		/* RFC6824 requires a DSS mapping with specific values

		 * if DATA_FIN is set but no data payload is mapped

		 */

		ext->data_fin = 1;

		ext->use_map = 1;

		ext->dsn64 = 1;

		ext->data_seq = mptcp_sk(subflow->conn)->write_seq;

		ext->data_seq = subflow->data_fin_tx_seq;

		ext->subflow_seq = 0;

		ext->data_len = 1;

	} else {

		/* If there's an existing DSS mapping, DATA_FIN consumes

		 * 1 additional byte of mapping space.

	} else if (ext->data_seq + ext->data_len == subflow->data_fin_tx_seq) {

		/* If there's an existing DSS mapping and it is the

		 * final mapping, DATA_FIN consumes 1 additional byte of

		 * mapping space.

		 */

		ext->data_fin = 1;

		ext->data_len++;

	}

}
@@ -354,8 +355,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, 
		if (mpext)

			opts->ext_copy = *mpext;



		if (skb && tcp_fin &&

		    subflow->conn->sk_state != TCP_ESTABLISHED)

		if (skb && tcp_fin && subflow->data_fin_tx_enable)

			mptcp_write_data_fin(subflow, &opts->ext_copy);

		ret = true;

	}

net/mptcp/protocol.c

+27 −5
Original line number Diff line number Diff line
@@ -419,6 +419,15 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
		return -EOPNOTSUPP;



	lock_sock(sk);



	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);



	if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {

		ret = sk_stream_wait_connect(sk, &timeo);

		if (ret)

			goto out;

	}



	ssock = __mptcp_tcp_fallback(msk);

	if (unlikely(ssock)) {

fallback:
@@ -427,8 +436,6 @@ fallback: 
		return ret >= 0 ? ret + copied : (copied ? copied : ret);

	}



	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);



	ssk = mptcp_subflow_get(msk);

	if (!ssk) {

		release_sock(sk);
@@ -460,6 +467,7 @@ fallback: 


	ssk_check_wmem(msk, ssk);

	release_sock(ssk);

out:

	release_sock(sk);

	return ret;

}
@@ -712,7 +720,8 @@ static void mptcp_cancel_work(struct sock *sk) 
		sock_put(sk);

}



static void mptcp_subflow_shutdown(struct sock *ssk, int how)

static void mptcp_subflow_shutdown(struct sock *ssk, int how,

				   bool data_fin_tx_enable, u64 data_fin_tx_seq)

{

	lock_sock(ssk);
@@ -725,6 +734,14 @@ 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;

		}



		ssk->sk_shutdown |= how;

		tcp_shutdown(ssk, how);

		break;
@@ -741,6 +758,7 @@ 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);
@@ -749,11 +767,15 @@ static void mptcp_close(struct sock *sk, long timeout) 


	list_splice_init(&msk->conn_list, &conn_list);



	data_fin_tx_seq = msk->write_seq;



	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);

	}
@@ -846,7 +868,7 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 
			*err = -ENOBUFS;

			local_bh_enable();

			release_sock(sk);

			mptcp_subflow_shutdown(newsk, SHUT_RDWR + 1);

			mptcp_subflow_shutdown(newsk, SHUT_RDWR + 1, 0, 0);

			tcp_close(newsk, 0);

			return NULL;

		}
@@ -1301,7 +1323,7 @@ static int mptcp_shutdown(struct socket *sock, int how) 
	mptcp_for_each_subflow(msk, subflow) {

		struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);



		mptcp_subflow_shutdown(tcp_sk, how);

		mptcp_subflow_shutdown(tcp_sk, how, 1, msk->write_seq);

	}



out_unlock:

net/mptcp/protocol.h

+2 −0
Original line number Diff line number Diff line
@@ -125,7 +125,9 @@ struct mptcp_subflow_context { 
		mpc_map : 1,

		data_avail : 1,

		rx_eof : 1,

		data_fin_tx_enable : 1,

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

	u64	data_fin_tx_seq;



	struct	sock *tcp_sock;	    /* tcp sk backpointer */

	struct	sock *conn;	    /* parent mptcp_sock */

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