[PATCH net-next] vlan: implement vlan id and protocol changes

[Chas Williams <3chas3@gmail.com>]

From: "Charles (Chas) Williams" <ciwillia@mail.eng.vyatta.net>

vlan_changelink silently ignores attempts to change the vlan id
or protocol id of an existing vlan interface.  Implement by adding
the new vlan id and protocol to the interface's vlan group and then
removing the old vlan id and protocol from the vlan group.

Signed-off-by: Chas Williams <3chas3@gmail.com>
---
 include/linux/netdevice.h |  1 +
 net/8021q/vlan.c          |  4 ++--
 net/8021q/vlan.h          |  2 ++
 net/8021q/vlan_netlink.c  | 38 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3ec9850c7936..a95ae238addf 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2409,6 +2409,7 @@ enum netdev_cmd {
 	NETDEV_CVLAN_FILTER_DROP_INFO,
 	NETDEV_SVLAN_FILTER_PUSH_INFO,
 	NETDEV_SVLAN_FILTER_DROP_INFO,
+	NETDEV_CHANGEVLAN,
 };
 const char *netdev_cmd_to_name(enum netdev_cmd cmd);
 
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index 73a65789271b..b5e0ad1a581a 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -51,8 +51,8 @@ const char vlan_version[] = DRV_VERSION;
 
 /* End of global variables definitions. */
 
-static int vlan_group_prealloc_vid(struct vlan_group *vg,
-				   __be16 vlan_proto, u16 vlan_id)
+int vlan_group_prealloc_vid(struct vlan_group *vg,
+			    __be16 vlan_proto, u16 vlan_id)
 {
 	struct net_device **array;
 	unsigned int pidx, vidx;
diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h
index 44df1c3df02d..c734dd21d70d 100644
--- a/net/8021q/vlan.h
+++ b/net/8021q/vlan.h
@@ -116,6 +116,8 @@ int register_vlan_dev(struct net_device *dev, struct netlink_ext_ack *extack);
 void unregister_vlan_dev(struct net_device *dev, struct list_head *head);
 bool vlan_dev_inherit_address(struct net_device *dev,
 			      struct net_device *real_dev);
+int vlan_group_prealloc_vid(struct vlan_group *vg,
+			    __be16 vlan_proto, u16 vlan_id);
 
 static inline u32 vlan_get_ingress_priority(struct net_device *dev,
 					    u16 vlan_tci)
diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c
index 9b60c1e399e2..0e59babe6651 100644
--- a/net/8021q/vlan_netlink.c
+++ b/net/8021q/vlan_netlink.c
@@ -107,10 +107,48 @@ static int vlan_changelink(struct net_device *dev, struct nlattr *tb[],
 			   struct nlattr *data[],
 			   struct netlink_ext_ack *extack)
 {
+	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
 	struct ifla_vlan_flags *flags;
 	struct ifla_vlan_qos_mapping *m;
 	struct nlattr *attr;
 	int rem;
+	int err;
+	__be16 vlan_proto = vlan->vlan_proto;
+	u16 vlan_id = vlan->vlan_id;
+
+	if (data[IFLA_VLAN_ID])
+		vlan_id = nla_get_u16(data[IFLA_VLAN_ID]);
+
+	if (data[IFLA_VLAN_PROTOCOL])
+		vlan_proto = nla_get_be16(data[IFLA_VLAN_PROTOCOL]);
+
+	if (vlan->vlan_id != vlan_id || vlan->vlan_proto != vlan_proto) {
+		struct net_device *real_dev = vlan->real_dev;
+		struct vlan_info *vlan_info;
+		struct vlan_group *grp;
+		__be16 old_vlan_proto = vlan->vlan_proto;
+		u16 old_vlan_id = vlan->vlan_id;
+
+		err = vlan_vid_add(real_dev, vlan_proto, vlan_id);
+		if (err)
+			return err;
+		vlan_info = rtnl_dereference(real_dev->vlan_info);
+		grp = &vlan_info->grp;
+		err = vlan_group_prealloc_vid(grp, vlan_proto, vlan_id);
+		if (err < 0) {
+			vlan_vid_del(real_dev, vlan_proto, vlan_id);
+			return err;
+		}
+		vlan_group_set_device(grp, vlan_proto, vlan_id, dev);
+		vlan->vlan_proto = vlan_proto;
+		vlan->vlan_id = vlan_id;
+
+		vlan_group_set_device(grp, old_vlan_proto, old_vlan_id, NULL);
+		vlan_vid_del(real_dev, old_vlan_proto, old_vlan_id);
+
+		err = call_netdevice_notifiers(NETDEV_CHANGEVLAN, dev);
+		notifier_to_errno(err);
+	}
 
 	if (data[IFLA_VLAN_FLAGS]) {
 		flags = nla_data(data[IFLA_VLAN_FLAGS]);
-- 
2.14.3