[PATCH net 2/5] mptcp: fix NL PM announced address accounting

[Matthieu Baerts (NGI0)]

From: Paolo Abeni <pabeni@xxxxxxxxxx>

Currently the per connection announced address counter is never
decreased. As a consequence, after connection establishment, if
the NL PM deletes an endpoint and adds a new/different one, no
additional subflow is created for the new endpoint even if the
current limits allow that.

Address the issue properly updating the signaled address counter
every time the NL PM removes such addresses.

Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
 net/mptcp/pm_netlink.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index b399f2b7a369..f65831de5c1a 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1401,6 +1401,7 @@ static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
 	ret = remove_anno_list_by_saddr(msk, addr);
 	if (ret || force) {
 		spin_lock_bh(&msk->pm.lock);
+		msk->pm.add_addr_signaled -= ret;
 		mptcp_pm_remove_addr(msk, &list);
 		spin_unlock_bh(&msk->pm.lock);
 	}
@@ -1565,17 +1566,18 @@ static void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
 	struct mptcp_pm_addr_entry *entry;
 
 	list_for_each_entry(entry, rm_list, list) {
-		if (lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) &&
-		    slist.nr < MPTCP_RM_IDS_MAX)
+		if (slist.nr < MPTCP_RM_IDS_MAX &&
+		    lookup_subflow_by_saddr(&msk->conn_list, &entry->addr))
 			slist.ids[slist.nr++] = entry->addr.id;
 
-		if (remove_anno_list_by_saddr(msk, &entry->addr) &&
-		    alist.nr < MPTCP_RM_IDS_MAX)
+		if (alist.nr < MPTCP_RM_IDS_MAX &&
+		    remove_anno_list_by_saddr(msk, &entry->addr))
 			alist.ids[alist.nr++] = entry->addr.id;
 	}
 
 	if (alist.nr) {
 		spin_lock_bh(&msk->pm.lock);
+		msk->pm.add_addr_signaled -= alist.nr;
 		mptcp_pm_remove_addr(msk, &alist);
 		spin_unlock_bh(&msk->pm.lock);
 	}

-- 
2.45.2