Commit 478d7700 authored by Geliang Tang's avatar Geliang Tang Committed by David S. Miller
Browse files

mptcp: send out MP_FAIL when data checksum fails 



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: default avatarGeliang Tang <geliangtang@xiaomi.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5580d41b

net/mptcp/protocol.h

+13 −0
Original line number Diff line number Diff line
@@ -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);

net/mptcp/subflow.c

+15 −0
Original line number Diff line number Diff line
@@ -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 @@ static bool subflow_check_data_avail(struct sock *ssk) 


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