mptcp: update local address flags when setting it

commit e0266319 upstream.

Just like in-kernel pm, when userspace pm does set_flags, it needs to send
out MP_PRIO signal, and also modify the flags of the corresponding address
entry in the local address list. This patch implements the missing logic.

Traverse all address entries on userspace_pm_local_addr_list to find the
local address entry, if bkup is true, set the flags of this entry with
FLAG_BACKUP, otherwise, clear FLAG_BACKUP.

Fixes: 892f396c ("mptcp: netlink: issue MP_PRIO signals from userspace PMs")
Cc: stable@vger.kernel.org
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241112-net-mptcp-misc-6-12-pm-v1-1-b835580cefa8@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ Conflicts in pm_userspace.c, because commit 6a42477f ("mptcp:
  update set_flags interfaces"), is not in this version, and causes too
  many conflicts when backporting it. The same code can still be added
  at the same place, before sending the ACK. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/mptcp/pm_userspace.c

@@ -565,6 +565,7 @@ int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
 				 struct mptcp_pm_addr_entry *loc,
 				 struct mptcp_pm_addr_entry *rem, u8 bkup)
 {
+	struct mptcp_pm_addr_entry *entry;
 	struct mptcp_sock *msk;
 	int ret = -EINVAL;
 	struct sock *sk;
@@ -585,6 +586,17 @@ int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
 	    rem->addr.family == AF_UNSPEC)
 		goto set_flags_err;
 
+	spin_lock_bh(&msk->pm.lock);
+	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
+		if (mptcp_addresses_equal(&entry->addr, &loc->addr, false)) {
+			if (bkup)
+				entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
+			else
+				entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+		}
+	}
+	spin_unlock_bh(&msk->pm.lock);
+
 	lock_sock(sk);
 	ret = mptcp_pm_nl_mp_prio_send_ack(msk, &loc->addr, &rem->addr, bkup);
 	release_sock(sk);