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mptcp: pm: only decrement add_addr_accepted for MPJ req

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Adding the following warning ...

  WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)

... before decrementing the add_addr_accepted counter helped to find a
bug when running the "remove single subflow" subtest from the
mptcp_join.sh selftest.

Removing a 'subflow' endpoint will first trigger a RM_ADDR, then the
subflow closure. Before this patch, and upon the reception of the
RM_ADDR, the other peer will then try to decrement this
add_addr_accepted. That's not correct because the attached subflows have
not been created upon the reception of an ADD_ADDR.

A way to solve that is to decrement the counter only if the attached
subflow was an MP_JOIN to a remote id that was not 0, and initiated by
the host receiving the RM_ADDR.

Fixes: d0876b2284 ("mptcp: add the incoming RM_ADDR support")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-9-38035d40de5b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Matthieu Baerts (NGI0) 2024-08-19 21:45:27 +02:00 committed by Jakub Kicinski
parent 322ea37789
commit 1c1f721375
1 changed files with 6 additions and 2 deletions
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8
net/mptcp/pm_netlink.c
View File

@ -829,7 +829,7 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
mptcp_close_ssk(sk, ssk, subflow);
spin_lock_bh(&msk->pm.lock);
removed = true;
removed |= subflow->request_join;
if (rm_type == MPTCP_MIB_RMSUBFLOW)
__MPTCP_INC_STATS(sock_net(sk), rm_type);
}
@ -843,7 +843,11 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
if (!mptcp_pm_is_kernel(msk))
continue;
if (rm_type == MPTCP_MIB_RMADDR) {
if (rm_type == MPTCP_MIB_RMADDR && rm_id &&
!WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) {
/* Note: if the subflow has been closed before, this
* add_addr_accepted counter will not be decremented.
*/
msk->pm.add_addr_accepted--;
WRITE_ONCE(msk->pm.accept_addr, true);
}