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mptcp: send out MP_FAIL when data checksum fails

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When a bad checksum is detected, set the send_mp_fail flag to send out
the MP_FAIL option.

Add a new function mptcp_has_another_subflow() to check whether there's
only a single subflow.

When multiple subflows are in use, close the affected subflow with a RST
that includes an MP_FAIL option and discard the data with the bad
checksum.

Set the sk_state of the subsocket to TCP_CLOSE, then the flag
MPTCP_WORK_CLOSE_SUBFLOW will be set in subflow_sched_work_if_closed,
and the subflow will be closed.

When a single subfow is in use, temporarily handled by sending MP_FAIL
with a RST too.

Signed-off-by: Geliang Tang <geliangtang@xiaomi.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:
Geliang Tang 2021-08-24 16:26:17 -07:00 committed by David S. Miller
parent 5580d41b75
commit 478d770008
2 changed files with 28 additions and 0 deletions
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13
net/mptcp/protocol.h
View File

@ -614,6 +614,19 @@ static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
}
static inline bool mptcp_has_another_subflow(struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk), *tmp;
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
mptcp_for_each_subflow(msk, tmp) {
if (tmp != subflow)
return true;
}
return false;
}
void __init mptcp_proto_init(void);
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
int __init mptcp_proto_v6_init(void);

15
net/mptcp/subflow.c
View File

@ -910,6 +910,7 @@ static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *
csum = csum_partial(&header, sizeof(header), subflow->map_data_csum);
if (unlikely(csum_fold(csum))) {
MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DATACSUMERR);
subflow->send_mp_fail = 1;
return subflow->mp_join ? MAPPING_INVALID : MAPPING_DUMMY;
}
@ -1157,6 +1158,20 @@ no_data:
fallback:
/* RFC 8684 section 3.7. */
if (subflow->send_mp_fail) {
if (mptcp_has_another_subflow(ssk)) {
while ((skb = skb_peek(&ssk->sk_receive_queue)))
sk_eat_skb(ssk, skb);
}
ssk->sk_err = EBADMSG;
tcp_set_state(ssk, TCP_CLOSE);
subflow->reset_transient = 0;
subflow->reset_reason = MPTCP_RST_EMIDDLEBOX;
tcp_send_active_reset(ssk, GFP_ATOMIC);
WRITE_ONCE(subflow->data_avail, 0);
return true;
}
if (subflow->mp_join || subflow->fully_established) {
/* fatal protocol error, close the socket.
* subflow_error_report() will introduce the appropriate barriers