[MPTCP][PATCH v2 mptcp-next 06/10] mptcp: add netdev down event handler

[Geliang Tang <geliangtang@gmail.com>]

This patch added the net device DOWN event handler function named
mptcp_fm_cmd_del_addr. In it, traverse the local address list to find
the deleting address entry, pass this entry to mptcp_pm_free_addr_entry,
then start the rcu_work to remove the subflow and signal the RM_ADDR
suboption.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
 net/mptcp/pm_fullmesh.c |  2 ++
 net/mptcp/pm_netlink.c  | 20 ++++++++++++++++++++
 net/mptcp/protocol.h    |  1 +
 3 files changed, 23 insertions(+)

diff --git a/net/mptcp/pm_fullmesh.c b/net/mptcp/pm_fullmesh.c
index 6c52a64657f4..beb6e4c7cf46 100644
--- a/net/mptcp/pm_fullmesh.c
+++ b/net/mptcp/pm_fullmesh.c
@@ -17,6 +17,8 @@ static void addr_event_handler(unsigned long event, struct net *net,
 
 	if (event == NETDEV_UP)
 		mptcp_fm_cmd_add_addr(net, addr);
+	else if (event == NETDEV_DOWN)
+		mptcp_fm_cmd_del_addr(net, addr);
 }
 
 static int mptcp_pm_addr4_event(struct notifier_block *this,
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 533818b4dba2..765d59dd2a5d 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1984,6 +1984,26 @@ int mptcp_fm_cmd_add_addr(struct net *net, const struct mptcp_addr_info *addr)
 	return 0;
 }
 
+int mptcp_fm_cmd_del_addr(struct net *net, struct mptcp_addr_info *addr)
+{
+	struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
+	struct mptcp_pm_addr_entry *entry, *tmp;
+
+	spin_lock_bh(&pernet->lock);
+	list_for_each_entry_safe(entry, tmp, &pernet->local_addr_list, list) {
+		if (addresses_equal(&entry->addr, addr, false)) {
+			list_del_rcu(&entry->list);
+			spin_unlock_bh(&pernet->lock);
+			mptcp_pm_free_addr_entry(net, entry);
+
+			return 0;
+		}
+	}
+	spin_unlock_bh(&pernet->lock);
+
+	return 0;
+}
+
 #endif
 
 static int __net_init pm_nl_init_net(struct net *net)
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 78a9cd90b0f9..1dbd8de17a22 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -813,6 +813,7 @@ unsigned int mptcp_pm_get_local_addr_max(struct mptcp_sock *msk);
 #if IS_ENABLED(CONFIG_MPTCP_FULLMESH)
 void __init mptcp_pm_fm_init(void);
 int mptcp_fm_cmd_add_addr(struct net *net, const struct mptcp_addr_info *addr);
+int mptcp_fm_cmd_del_addr(struct net *net, struct mptcp_addr_info *addr);
 #endif
 
 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
-- 
2.31.1