Commit 12a18341 authored by Yonglong Li's avatar Yonglong Li Committed by Jakub Kicinski
Browse files

mptcp: send ADD_ADDR echo before create subflows 



In some corner cases, the peer handing an incoming ADD_ADDR option, can
receive a retransmitted ADD_ADDR for the same address before the subflow
creation completes.

We can avoid the above issue by generating and sending the ADD_ADDR echo
before starting the MPJ subflow connection.

This slightly changes the behaviour of the packetdrill tests as the
ADD_ADDR echo packet is sent earlier.

Acked-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarYonglong Li <liyonglong@chinatelecom.cn>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/20220317221444.426335-1-mathew.j.martineau@linux.intel.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 4edf21aa

net/mptcp/pm_netlink.c

+5 −13
Original line number Diff line number Diff line
@@ -650,7 +650,6 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk) 
	unsigned int add_addr_accept_max;

	struct mptcp_addr_info remote;

	unsigned int subflows_max;

	bool reset_port = false;

	int i, nr;



	add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
@@ -661,14 +660,15 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk) 
		 msk->pm.remote.family);



	remote = msk->pm.remote;

	mptcp_pm_announce_addr(msk, &remote, true);

	mptcp_pm_nl_addr_send_ack(msk);



	if (lookup_subflow_by_daddr(&msk->conn_list, &remote))

		goto add_addr_echo;

		return;



	/* pick id 0 port, if none is provided the remote address */

	if (!remote.port) {

		reset_port = true;

	if (!remote.port)

		remote.port = sk->sk_dport;

	}



	/* connect to the specified remote address, using whatever

	 * local address the routing configuration will pick.
@@ -684,14 +684,6 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk) 
	for (i = 0; i < nr; i++)

		__mptcp_subflow_connect(sk, &addrs[i], &remote);

	spin_lock_bh(&msk->pm.lock);



	/* be sure to echo exactly the received address */

	if (reset_port)

		remote.port = 0;



add_addr_echo:

	mptcp_pm_announce_addr(msk, &remote, true);

	mptcp_pm_nl_addr_send_ack(msk);

}



void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)