l2tp: export l2tp_tunnel_closeall

l2tp_core internally uses l2tp_tunnel_closeall to close all sessions in a
tunnel when a UDP-encapsulation socket is destroyed.  We need to do something
similar for IP-encapsulation sockets.

Export l2tp_tunnel_closeall as a GPL symbol to enable l2tp_ip and l2tp_ip6 to
call it from their .destroy handlers.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/l2tp/l2tp_core.c

@@ -114,7 +114,6 @@ struct l2tp_net {
 
 static void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
-static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 
 static inline struct l2tp_net *l2tp_pernet(struct net *net)
 {
@@ -1312,7 +1311,7 @@ static void l2tp_tunnel_destruct(struct sock *sk)
 
 /* When the tunnel is closed, all the attached sessions need to go too.
  */
-static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
+void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
 {
 	int hash;
 	struct hlist_node *walk;
@@ -1375,6 +1374,7 @@ static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
 	}
 	write_unlock_bh(&tunnel->hlist_lock);
 }
+EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall);
 
 /* Tunnel socket destroy hook for UDP encapsulation */
 static void l2tp_udp_encap_destroy(struct sock *sk)

net/l2tp/l2tp_core.h

@@ -240,6 +240,7 @@ extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 
 extern int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp);
+extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 extern struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 extern int l2tp_session_delete(struct l2tp_session *session);