ip_vti: not register vti_ipip_handler twice

An xfrm_tunnel object is linked into the list when registering,
so vti_ipip_handler can not be registered twice, otherwise its
next pointer will be overwritten on the second time.

So this patch is to define a new xfrm_tunnel object to register
for AF_INET6.

Fixes: e6ce6457 ("ip_vti: support IPIP6 tunnel processing")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/ipv4/ip_vti.c

@@ -484,6 +484,13 @@ static struct xfrm_tunnel vti_ipip_handler __read_mostly = {
 	.err_handler	=	vti4_err,
 	.priority	=	0,
 };
+
+static struct xfrm_tunnel vti_ipip6_handler __read_mostly = {
+	.handler	=	vti_rcv_tunnel,
+	.cb_handler	=	vti_rcv_cb,
+	.err_handler	=	vti4_err,
+	.priority	=	0,
+};
 #endif
 
 static int __net_init vti_init_net(struct net *net)
@@ -660,7 +667,7 @@ static int __init vti_init(void)
 	if (err < 0)
 		goto xfrm_tunnel_ipip_failed;
 #if IS_ENABLED(CONFIG_IPV6)
-	err = xfrm4_tunnel_register(&vti_ipip_handler, AF_INET6);
+	err = xfrm4_tunnel_register(&vti_ipip6_handler, AF_INET6);
 	if (err < 0)
 		goto xfrm_tunnel_ipip6_failed;
 #endif
@@ -676,7 +683,7 @@ static int __init vti_init(void)
 rtnl_link_failed:
 #if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
 #if IS_ENABLED(CONFIG_IPV6)
-	xfrm4_tunnel_deregister(&vti_ipip_handler, AF_INET6);
+	xfrm4_tunnel_deregister(&vti_ipip6_handler, AF_INET6);
 xfrm_tunnel_ipip6_failed:
 #endif
 	xfrm4_tunnel_deregister(&vti_ipip_handler, AF_INET);
@@ -699,7 +706,7 @@ static void __exit vti_fini(void)
 	rtnl_link_unregister(&vti_link_ops);
 #if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
 #if IS_ENABLED(CONFIG_IPV6)
-	xfrm4_tunnel_deregister(&vti_ipip_handler, AF_INET6);
+	xfrm4_tunnel_deregister(&vti_ipip6_handler, AF_INET6);
 #endif
 	xfrm4_tunnel_deregister(&vti_ipip_handler, AF_INET);
 #endif