unimore/kernel-hacking-2024-linux-steffo
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mptcp: send explicit ack on delayed ack_seq incr

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When the worker moves some bytes from the OoO queue into
the receive queue, the msk->ask_seq is updated, the MPTCP-level
ack carrying that value needs to wait the next ingress packet,
possibly slowing down or hanging the peer

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Paolo Abeni 2020-11-16 10:48:14 +01:00 committed by Jakub Kicinski
parent 6f8a612a33
commit 7ed90803a2
1 changed files with 21 additions and 13 deletions
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34
net/mptcp/protocol.c
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@ -407,13 +407,27 @@ static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
}
static void mptcp_check_data_fin(struct sock *sk)
static void mptcp_send_ack(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
lock_sock(ssk);
tcp_send_ack(ssk);
release_sock(ssk);
}
}
static bool mptcp_check_data_fin(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
u64 rcv_data_fin_seq;
bool ret = false;
if (__mptcp_check_fallback(msk) || !msk->first)
return;
return ret;
/* Need to ack a DATA_FIN received from a peer while this side
* of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
@ -429,8 +443,6 @@ static void mptcp_check_data_fin(struct sock *sk)
*/
if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
struct mptcp_subflow_context *subflow;
WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
WRITE_ONCE(msk->rcv_data_fin, 0);
@ -454,17 +466,12 @@ static void mptcp_check_data_fin(struct sock *sk)
break;
}
ret = true;
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);
}
mptcp_send_ack(msk);
mptcp_close_wake_up(sk);
}
return ret;
}
static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
@ -1547,7 +1554,8 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk)
} while (!done);
if (mptcp_ofo_queue(msk) || moved > 0) {
mptcp_check_data_fin((struct sock *)msk);
if (!mptcp_check_data_fin((struct sock *)msk))
mptcp_send_ack(msk);
return true;
}
return false;