Commit 15cc1045 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
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mptcp: deliver ssk errors to msk 



Currently all errors received on msk subflows are ignored.
We need to catch at least the errors on connect() and
on fallback sockets.

Use a custom sk_error_report callback at subflow level,
and do the real action under the msk socket lock - via
the usual sock_owned_by_user()/release_callback() schema.

Fixes: 6e628cd3 ("mptcp: use mptcp release_cb for delayed tasks")
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4c0d2e96

net/mptcp/protocol.c

+7 −0
Original line number Diff line number Diff line
@@ -2959,6 +2959,8 @@ static void mptcp_release_cb(struct sock *sk) 
		mptcp_push_pending(sk, 0);

		spin_lock_bh(&sk->sk_lock.slock);

	}

	if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags))

		__mptcp_error_report(sk);



	/* clear any wmem reservation and errors */

	__mptcp_update_wmem(sk);
@@ -3355,6 +3357,11 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock, 
	if (sk->sk_shutdown & RCV_SHUTDOWN)

		mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;



	/* This barrier is coupled with smp_wmb() in tcp_reset() */

	smp_rmb();

	if (sk->sk_err)

		mask |= EPOLLERR;



	return mask;

}

net/mptcp/protocol.h

+4 −0
Original line number Diff line number Diff line
@@ -95,6 +95,7 @@ 
#define MPTCP_WORK_CLOSE_SUBFLOW 5

#define MPTCP_PUSH_PENDING	6

#define MPTCP_CLEAN_UNA		7

#define MPTCP_ERROR_REPORT	8



static inline bool before64(__u64 seq1, __u64 seq2)

{
@@ -414,6 +415,7 @@ struct mptcp_subflow_context { 
	void	(*tcp_data_ready)(struct sock *sk);

	void	(*tcp_state_change)(struct sock *sk);

	void	(*tcp_write_space)(struct sock *sk);

	void	(*tcp_error_report)(struct sock *sk);



	struct	rcu_head rcu;

};
@@ -478,6 +480,7 @@ static inline void mptcp_subflow_tcp_fallback(struct sock *sk, 
	sk->sk_data_ready = ctx->tcp_data_ready;

	sk->sk_state_change = ctx->tcp_state_change;

	sk->sk_write_space = ctx->tcp_write_space;

	sk->sk_error_report = ctx->tcp_error_report;



	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;

}
@@ -505,6 +508,7 @@ bool mptcp_finish_join(struct sock *sk); 
bool mptcp_schedule_work(struct sock *sk);

void __mptcp_check_push(struct sock *sk, struct sock *ssk);

void __mptcp_data_acked(struct sock *sk);

void __mptcp_error_report(struct sock *sk);

void mptcp_subflow_eof(struct sock *sk);

bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);

void __mptcp_flush_join_list(struct mptcp_sock *msk);

net/mptcp/subflow.c

+43 −0
Original line number Diff line number Diff line
@@ -1043,6 +1043,46 @@ static void subflow_write_space(struct sock *ssk) 
	/* we take action in __mptcp_clean_una() */

}



void __mptcp_error_report(struct sock *sk)

{

	struct mptcp_subflow_context *subflow;

	struct mptcp_sock *msk = mptcp_sk(sk);



	mptcp_for_each_subflow(msk, subflow) {

		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);

		int err = sock_error(ssk);



		if (!err)

			continue;



		/* only propagate errors on fallen-back sockets or

		 * on MPC connect

		 */

		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))

			continue;



		inet_sk_state_store(sk, inet_sk_state_load(ssk));

		sk->sk_err = -err;



		/* This barrier is coupled with smp_rmb() in mptcp_poll() */

		smp_wmb();

		sk->sk_error_report(sk);

		break;

	}

}



static void subflow_error_report(struct sock *ssk)

{

	struct sock *sk = mptcp_subflow_ctx(ssk)->conn;



	mptcp_data_lock(sk);

	if (!sock_owned_by_user(sk))

		__mptcp_error_report(sk);

	else

		set_bit(MPTCP_ERROR_REPORT,  &mptcp_sk(sk)->flags);

	mptcp_data_unlock(sk);

}



static struct inet_connection_sock_af_ops *

subflow_default_af_ops(struct sock *sk)

{
@@ -1352,9 +1392,11 @@ static int subflow_ulp_init(struct sock *sk) 
	ctx->tcp_data_ready = sk->sk_data_ready;

	ctx->tcp_state_change = sk->sk_state_change;

	ctx->tcp_write_space = sk->sk_write_space;

	ctx->tcp_error_report = sk->sk_error_report;

	sk->sk_data_ready = subflow_data_ready;

	sk->sk_write_space = subflow_write_space;

	sk->sk_state_change = subflow_state_change;

	sk->sk_error_report = subflow_error_report;

out:

	return err;

}
@@ -1407,6 +1449,7 @@ static void subflow_ulp_clone(const struct request_sock *req, 
	new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;

	new_ctx->tcp_state_change = old_ctx->tcp_state_change;

	new_ctx->tcp_write_space = old_ctx->tcp_write_space;

	new_ctx->tcp_error_report = old_ctx->tcp_error_report;

	new_ctx->rel_write_seq = 1;

	new_ctx->tcp_sock = newsk;