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mptcp: Retransmit DATA_FIN

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With this change, the MPTCP-level retransmission timer is used to resend
DATA_FIN. The retranmit timer is not stopped while waiting for a
MPTCP-level ACK of DATA_FIN, and retransmitted DATA_FINs are sent on all
subflows. The retry interval starts at TCP_RTO_MIN and then doubles on
each attempt, up to TCP_RTO_MAX.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/146
Fixes: 43b54c6ee3 ("mptcp: Use full MPTCP-level disconnect state machine")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mat Martineau 2021-04-23 09:40:33 -07:00 committed by David S. Miller
parent d13f048dd4
commit 6477dd39e6
1 changed files with 23 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

25
net/mptcp/protocol.c
View file

@ -399,6 +399,14 @@ static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
return false;
}
static void mptcp_set_datafin_timeout(const struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
mptcp_sk(sk)->timer_ival = min(TCP_RTO_MAX,
TCP_RTO_MIN << icsk->icsk_retransmits);
}
static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
{
long tout = ssk && inet_csk(ssk)->icsk_pending ?
@ -1052,7 +1060,7 @@ static void __mptcp_clean_una(struct sock *sk)
}
if (snd_una == READ_ONCE(msk->snd_nxt)) {
if (msk->timer_ival)
if (msk->timer_ival && !mptcp_data_fin_enabled(msk))
mptcp_stop_timer(sk);
} else {
mptcp_reset_timer(sk);
@ -2276,8 +2284,19 @@ static void __mptcp_retrans(struct sock *sk)
__mptcp_clean_una_wakeup(sk);
dfrag = mptcp_rtx_head(sk);
if (!dfrag)
if (!dfrag) {
if (mptcp_data_fin_enabled(msk)) {
struct inet_connection_sock *icsk = inet_csk(sk);
icsk->icsk_retransmits++;
mptcp_set_datafin_timeout(sk);
mptcp_send_ack(msk);
goto reset_timer;
}
return;
}
ssk = mptcp_subflow_get_retrans(msk);
if (!ssk)
@ -2460,6 +2479,8 @@ void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
pr_debug("Sending DATA_FIN on subflow %p", ssk);
mptcp_set_timeout(sk, ssk);
tcp_send_ack(ssk);
if (!mptcp_timer_pending(sk))
mptcp_reset_timer(sk);
}
break;
}