Commit dea2b1ea authored by Paolo Abeni's avatar Paolo Abeni Committed by Jakub Kicinski

mptcp: do not reset MP_CAPABLE subflow on mapping errors

When some mapping related errors occurs we close the main
MPC subflow with a RST. We should instead fallback gracefully
to TCP, and do the reset only for MPJ subflows.

Fixes: d22f4988 ("mptcp: process MP_CAPABLE data option")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/192Reported-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
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 avatarJakub Kicinski <kuba@kernel.org>
parent 06f9a435
......@@ -1011,21 +1011,11 @@ static bool subflow_check_data_avail(struct sock *ssk)
status = get_mapping_status(ssk, msk);
trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue));
if (status == MAPPING_INVALID) {
ssk->sk_err = EBADMSG;
goto fatal;
}
if (status == MAPPING_DUMMY) {
__mptcp_do_fallback(msk);
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->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
return true;
}
if (unlikely(status == MAPPING_INVALID))
goto fallback;
if (unlikely(status == MAPPING_DUMMY))
goto fallback;
if (status != MAPPING_OK)
goto no_data;
......@@ -1038,10 +1028,8 @@ static bool subflow_check_data_avail(struct sock *ssk)
* MP_CAPABLE-based mapping
*/
if (unlikely(!READ_ONCE(msk->can_ack))) {
if (!subflow->mpc_map) {
ssk->sk_err = EBADMSG;
goto fatal;
}
if (!subflow->mpc_map)
goto fallback;
WRITE_ONCE(msk->remote_key, subflow->remote_key);
WRITE_ONCE(msk->ack_seq, subflow->map_seq);
WRITE_ONCE(msk->can_ack, true);
......@@ -1069,17 +1057,31 @@ static bool subflow_check_data_avail(struct sock *ssk)
no_data:
subflow_sched_work_if_closed(msk, ssk);
return false;
fatal:
/* fatal protocol error, close the socket */
/* This barrier is coupled with smp_rmb() in tcp_poll() */
smp_wmb();
ssk->sk_error_report(ssk);
tcp_set_state(ssk, TCP_CLOSE);
subflow->reset_transient = 0;
subflow->reset_reason = MPTCP_RST_EMPTCP;
tcp_send_active_reset(ssk, GFP_ATOMIC);
subflow->data_avail = 0;
return false;
fallback:
/* RFC 8684 section 3.7. */
if (subflow->mp_join || subflow->fully_established) {
/* fatal protocol error, close the socket.
* subflow_error_report() will introduce the appropriate barriers
*/
ssk->sk_err = EBADMSG;
ssk->sk_error_report(ssk);
tcp_set_state(ssk, TCP_CLOSE);
subflow->reset_transient = 0;
subflow->reset_reason = MPTCP_RST_EMPTCP;
tcp_send_active_reset(ssk, GFP_ATOMIC);
subflow->data_avail = 0;
return false;
}
__mptcp_do_fallback(msk);
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->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
return true;
}
bool mptcp_subflow_data_available(struct sock *sk)
......
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