Commit 76c42a29 authored by Mat Martineau's avatar Mat Martineau Committed by David S. Miller
Browse files

mptcp: Use per-subflow storage for DATA_FIN sequence number 



Instead of reading the MPTCP-level sequence number when sending DATA_FIN,
store the data in the subflow so it can be safely accessed when the
subflow TCP headers are written to the packet without the MPTCP-level
lock held. This also allows the MPTCP-level socket to close individual
subflows without closing the MPTCP connection.

Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1954b860

net/mptcp/options.c

+2 −3
Original line number Diff line number Diff line
@@ -312,7 +312,7 @@ static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, 
		 */

		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 {
@@ -354,8 +354,7 @@ 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

+17 −3
Original line number Diff line number Diff line
@@ -720,7 +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);
@@ -733,6 +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;
@@ -749,6 +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);
@@ -757,11 +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);

	}
@@ -854,7 +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;

		}
@@ -1309,7 +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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