Commit 2834f8ed authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski
Browse files

mptcp: cleanup fallback dummy mapping generation 



MPTCP currently access ack_seq outside the msk socket log scope to
generate the dummy mapping for fallback socket. Soon we are going
to introduce backlog usage and even for fallback socket the ack_seq
value will be significantly off outside of the msk socket lock scope.

Avoid relying on ack_seq for dummy mapping generation, using instead
the subflow sequence number. Note that in case of disconnect() and
(re)connect() we must ensure that any previous state is re-set.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarGeliang Tang <geliang@kernel.org>
Tested-by: default avatarGeliang Tang <geliang@kernel.org>
Reviewed-by: default avatarMat Martineau <martineau@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-6-1f34b6c1e0b1@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 85f22b8e

net/mptcp/protocol.c

+3 −0
Original line number Diff line number Diff line
@@ -3274,6 +3274,9 @@ static int mptcp_disconnect(struct sock *sk, int flags) 
	msk->bytes_retrans = 0;

	msk->rcvspace_init = 0;



	/* for fallback's sake */

	WRITE_ONCE(msk->ack_seq, 0);



	WRITE_ONCE(sk->sk_shutdown, 0);

	sk_error_report(sk);

	return 0;

net/mptcp/subflow.c

+7 −1
Original line number Diff line number Diff line
@@ -491,6 +491,9 @@ static void subflow_set_remote_key(struct mptcp_sock *msk, 
	mptcp_crypto_key_sha(subflow->remote_key, NULL, &subflow->iasn);

	subflow->iasn++;



	/* for fallback's sake */

	subflow->map_seq = subflow->iasn;



	WRITE_ONCE(msk->remote_key, subflow->remote_key);

	WRITE_ONCE(msk->ack_seq, subflow->iasn);

	WRITE_ONCE(msk->can_ack, true);
@@ -1435,9 +1438,12 @@ static bool subflow_check_data_avail(struct sock *ssk) 


	skb = skb_peek(&ssk->sk_receive_queue);

	subflow->map_valid = 1;

	subflow->map_seq = READ_ONCE(msk->ack_seq);

	subflow->map_data_len = skb->len;

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

	subflow->map_seq = __mptcp_expand_seq(subflow->map_seq,

					      subflow->iasn +

					      TCP_SKB_CB(skb)->seq -

					      subflow->ssn_offset - 1);

	WRITE_ONCE(subflow->data_avail, true);

	return true;

}