mptcp: update userspace pm infos

BugLink: https://bugs.launchpad.net/bugs/2029808

commit 77e4b94 upstream.

Increase pm subflows counter on both server side and client side when
userspace pm creates a new subflow, and decrease the counter when it
closes a subflow.

Increase add_addr_signaled counter in mptcp_nl_cmd_announce() when the
address is announced by userspace PM.

This modification is similar to how the in-kernel PM is updating the
counter: when additional subflows are created/removed.

Fixes: 9ab4807 ("mptcp: netlink: Add MPTCP_PM_CMD_ANNOUNCE")
Fixes: 702c2f6 ("mptcp: netlink: allow userspace-driven subflow establishment")
Closes: multipath-tcp/mptcp_net-next#329
Cc: stable@vger.kernel.org
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

net/mptcp/pm.c

@@ -87,8 +87,15 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
 	unsigned int subflows_max;
 	int ret = 0;
 
-	if (mptcp_pm_is_userspace(msk))
-		return mptcp_userspace_pm_active(msk);
+	if (mptcp_pm_is_userspace(msk)) {
+		if (mptcp_userspace_pm_active(msk)) {
+			spin_lock_bh(&pm->lock);
+			pm->subflows++;
+			spin_unlock_bh(&pm->lock);
+			return true;
+		}
+		return false;
+	}
 
 	subflows_max = mptcp_pm_get_subflows_max(msk);
 
@@ -181,8 +188,16 @@ void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, const struct sock *ssk,
 	struct mptcp_pm_data *pm = &msk->pm;
 	bool update_subflows;
 
-	update_subflows = (subflow->request_join || subflow->mp_join) &&
-			  mptcp_pm_is_kernel(msk);
+	update_subflows = subflow->request_join || subflow->mp_join;
+	if (mptcp_pm_is_userspace(msk)) {
+		if (update_subflows) {
+			spin_lock_bh(&pm->lock);
+			pm->subflows--;
+			spin_unlock_bh(&pm->lock);
+		}
+		return;
+	}
+
 	if (!READ_ONCE(pm->work_pending) && !update_subflows)
 		return;
 

net/mptcp/pm_userspace.c

@@ -69,6 +69,7 @@ int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 							MPTCP_PM_MAX_ADDR_ID + 1,
 							1);
 		list_add_tail_rcu(&e->list, &msk->pm.userspace_pm_local_addr_list);
+		msk->pm.local_addr_used++;
 		ret = e->addr.id;
 	} else if (match) {
 		ret = entry->addr.id;
@@ -95,6 +96,7 @@ static int mptcp_userspace_pm_delete_local_addr(struct mptcp_sock *msk,
 			 */
 			list_del_rcu(&entry->list);
 			kfree(entry);
+			msk->pm.local_addr_used--;
 			return 0;
 		}
 	}
@@ -194,6 +196,7 @@ int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info)
 	spin_lock_bh(&msk->pm.lock);
 
 	if (mptcp_pm_alloc_anno_list(msk, &addr_val)) {
+		msk->pm.add_addr_signaled++;
 		mptcp_pm_announce_addr(msk, &addr_val.addr, false);
 		mptcp_pm_nl_addr_send_ack(msk);
 	}
@@ -342,6 +345,8 @@ int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
 	spin_lock_bh(&msk->pm.lock);
 	if (err)
 		mptcp_userspace_pm_delete_local_addr(msk, &local);
+	else
+		msk->pm.subflows++;
 	spin_unlock_bh(&msk->pm.lock);
 
  create_err: