Commit 3721b9b6 authored by Mat Martineau's avatar Mat Martineau Committed by David S. Miller
Browse files

mptcp: Track received DATA_FIN sequence number and add related helpers 



Incoming DATA_FIN headers need to propagate the presence of the DATA_FIN
bit and the associated sequence number to the MPTCP layer, even when
arriving on a bare ACK that does not get added to the receive queue. Add
structure members to store the DATA_FIN information and helpers to set
and check those values.

Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7279da61

net/mptcp/options.c

+16 −0
Original line number Diff line number Diff line
@@ -782,6 +782,22 @@ static void update_una(struct mptcp_sock *msk, 
	}

}



bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq)

{

	/* Skip if DATA_FIN was already received.

	 * If updating simultaneously with the recvmsg loop, values

	 * should match. If they mismatch, the peer is misbehaving and

	 * we will prefer the most recent information.

	 */

	if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first))

		return false;



	WRITE_ONCE(msk->rcv_data_fin_seq, data_fin_seq);

	WRITE_ONCE(msk->rcv_data_fin, 1);



	return true;

}



static bool add_addr_hmac_valid(struct mptcp_sock *msk,

				struct mptcp_options_received *mp_opt)

{

net/mptcp/protocol.c

+96 −10
Original line number Diff line number Diff line
@@ -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
@@ -163,6 +164,101 @@ static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk, 
	return mptcp_subflow_data_available(ssk);

}



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;



		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)
@@ -303,16 +399,6 @@ 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);

net/mptcp/protocol.h

+3 −0
Original line number Diff line number Diff line
@@ -193,12 +193,14 @@ struct mptcp_sock { 
	u64		remote_key;

	u64		write_seq;

	u64		ack_seq;

	u64		rcv_data_fin_seq;

	atomic64_t	snd_una;

	unsigned long	timer_ival;

	u32		token;

	unsigned long	flags;

	bool		can_ack;

	bool		fully_established;

	bool		rcv_data_fin;

	bool		snd_data_fin_enable;

	spinlock_t	join_list_lock;

	struct work_struct work;
@@ -385,6 +387,7 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk); 
bool mptcp_finish_join(struct sock *sk);

void mptcp_data_acked(struct sock *sk);

void mptcp_subflow_eof(struct sock *sk);

bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq);



void __init mptcp_token_init(void);

static inline void mptcp_token_init_request(struct request_sock *req)

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